Merge branch 'master' of /usr/src/ntfs-2.6/
authorAnton Altaparmakov <aia21@cantab.net>
Wed, 19 Oct 2005 11:13:58 +0000 (12:13 +0100)
committerAnton Altaparmakov <aia21@cantab.net>
Wed, 19 Oct 2005 11:13:58 +0000 (12:13 +0100)
12 files changed:
Documentation/filesystems/ntfs.txt
fs/ntfs/ChangeLog
fs/ntfs/Makefile
fs/ntfs/aops.c
fs/ntfs/attrib.c
fs/ntfs/attrib.h
fs/ntfs/file.c
fs/ntfs/inode.c
fs/ntfs/lcnalloc.c
fs/ntfs/lcnalloc.h
fs/ntfs/malloc.h
fs/ntfs/mft.c

index a5fbc8e897fa6f2f4a768241c66372de7b3366e7..614de31249019d6ab29d0f59a0fccb90c971e5e1 100644 (file)
@@ -50,9 +50,14 @@ userspace utilities, etc.
 Features
 ========
 
-- This is a complete rewrite of the NTFS driver that used to be in the kernel.
-  This new driver implements NTFS read support and is functionally equivalent
-  to the old ntfs driver.
+- This is a complete rewrite of the NTFS driver that used to be in the 2.4 and
+  earlier kernels.  This new driver implements NTFS read support and is
+  functionally equivalent to the old ntfs driver and it also implements limited
+  write support.  The biggest limitation at present is that files/directories
+  cannot be created or deleted.  See below for the list of write features that
+  are so far supported.  Another limitation is that writing to compressed files
+  is not implemented at all.  Also, neither read nor write access to encrypted
+  files is so far implemented.
 - The new driver has full support for sparse files on NTFS 3.x volumes which
   the old driver isn't happy with.
 - The new driver supports execution of binaries due to mmap() now being
@@ -78,7 +83,20 @@ Features
 - The new driver supports fsync(2), fdatasync(2), and msync(2).
 - The new driver supports readv(2) and writev(2).
 - The new driver supports access time updates (including mtime and ctime).
-
+- The new driver supports truncate(2) and open(2) with O_TRUNC.  But at present
+  only very limited support for highly fragmented files, i.e. ones which have
+  their data attribute split across multiple extents, is included.  Another
+  limitation is that at present truncate(2) will never create sparse files,
+  since to mark a file sparse we need to modify the directory entry for the
+  file and we do not implement directory modifications yet.
+- The new driver supports write(2) which can both overwrite existing data and
+  extend the file size so that you can write beyond the existing data.  Also,
+  writing into sparse regions is supported and the holes are filled in with
+  clusters.  But at present only limited support for highly fragmented files,
+  i.e. ones which have their data attribute split across multiple extents, is
+  included.  Another limitation is that write(2) will never create sparse
+  files, since to mark a file sparse we need to modify the directory entry for
+  the file and we do not implement directory modifications yet.
 
 Supported mount options
 =======================
@@ -439,6 +457,22 @@ ChangeLog
 
 Note, a technical ChangeLog aimed at kernel hackers is in fs/ntfs/ChangeLog.
 
+2.1.25:
+       - Write support is now extended with write(2) being able to both
+         overwrite existing file data and to extend files.  Also, if a write
+         to a sparse region occurs, write(2) will fill in the hole.  Note,
+         mmap(2) based writes still do not support writing into holes or
+         writing beyond the initialized size.
+       - Write support has a new feature and that is that truncate(2) and
+         open(2) with O_TRUNC are now implemented thus files can be both made
+         smaller and larger.
+       - Note: Both write(2) and truncate(2)/open(2) with O_TRUNC still have
+         limitations in that they
+         - only provide limited support for highly fragmented files.
+         - only work on regular, i.e. uncompressed and unencrypted files.
+         - never create sparse files although this will change once directory
+           operations are implemented.
+       - Lots of bug fixes and enhancements across the board.
 2.1.24:
        - Support journals ($LogFile) which have been modified by chkdsk.  This
          means users can boot into Windows after we marked the volume dirty.
index de58579a1d0e77a84e4f7d5fcc63c8eadcbb494d..03015c7b236cd3fb8b38192ea875d6f2944c8f2f 100644 (file)
@@ -1,18 +1,15 @@
 ToDo/Notes:
        - Find and fix bugs.
-       - In between ntfs_prepare/commit_write, need exclusion between
-         simultaneous file extensions.  This is given to us by holding i_sem
-         on the inode.  The only places in the kernel when a file is resized
-         are prepare/commit write and truncate for both of which i_sem is
-         held.  Just have to be careful in readpage/writepage and all other
-         helpers not running under i_sem that we play nice...
-         Also need to be careful with initialized_size extention in
-         ntfs_prepare_write. Basically, just be _very_ careful in this code...
-         UPDATE: The only things that need to be checked are read/writepage
-         which do not hold i_sem.  Note writepage cannot change i_size but it
-         needs to cope with a concurrent i_size change, just like readpage.
-         Also both need to cope with concurrent changes to the other sizes,
-         i.e. initialized/allocated/compressed size, as well.
+       - The only places in the kernel where a file is resized are
+         ntfs_file_write*() and ntfs_truncate() for both of which i_sem is
+         held.  Just have to be careful in read-/writepage and other helpers
+         not running under i_sem that we play nice...  Also need to be careful
+         with initialized_size extension in ntfs_file_write*() and writepage.
+         UPDATE: The only things that need to be checked are the compressed
+         write and the other attribute resize/write cases like index
+         attributes, etc.  For now none of these are implemented so are safe.
+       - Implement filling in of holes in aops.c::ntfs_writepage() and its
+         helpers.
        - Implement mft.c::sync_mft_mirror_umount().  We currently will just
          leave the volume dirty on umount if the final iput(vol->mft_ino)
          causes a write of any mirrored mft records due to the mft mirror
@@ -22,6 +19,63 @@ ToDo/Notes:
        - Enable the code for setting the NT4 compatibility flag when we start
          making NTFS 1.2 specific modifications.
 
+2.1.25 - (Almost) fully implement write(2) and truncate(2).
+
+       - Change ntfs_map_runlist_nolock(), ntfs_attr_find_vcn_nolock() and
+         {__,}ntfs_cluster_free() to also take an optional attribute search
+         context as argument.  This allows calling these functions with the
+         mft record mapped.  Update all callers.
+       - Fix potential deadlock in ntfs_mft_data_extend_allocation_nolock()
+         error handling by passing in the active search context when calling
+         ntfs_cluster_free().
+       - Change ntfs_cluster_alloc() to take an extra boolean parameter
+         specifying whether the cluster are being allocated to extend an
+         attribute or to fill a hole.
+       - Change ntfs_attr_make_non_resident() to call ntfs_cluster_alloc()
+         with @is_extension set to TRUE and remove the runlist terminator
+         fixup code as this is now done by ntfs_cluster_alloc().
+       - Change ntfs_attr_make_non_resident to take the attribute value size
+         as an extra parameter.  This is needed since we need to know the size
+         before we can map the mft record and our callers always know it.  The
+         reason we cannot simply read the size from the vfs inode i_size is
+         that this is not necessarily uptodate.  This happens when
+         ntfs_attr_make_non_resident() is called in the ->truncate call path.
+       - Fix ntfs_attr_make_non_resident() to update the vfs inode i_blocks
+         which is zero for a resident attribute but should no longer be zero
+         once the attribute is non-resident as it then has real clusters
+         allocated.
+       - Add fs/ntfs/attrib.[hc]::ntfs_attr_extend_allocation(), a function to
+         extend the allocation of an attributes.  Optionally, the data size,
+         but not the initialized size can be extended, too.
+       - Implement fs/ntfs/inode.[hc]::ntfs_truncate().  It only supports
+         uncompressed and unencrypted files and it never creates sparse files
+         at least for the moment (making a file sparse requires us to modify
+         its directory entries and we do not support directory operations at
+         the moment).  Also, support for highly fragmented files, i.e. ones
+         whose data attribute is split across multiple extents, is severly
+         limited.  When such a case is encountered, EOPNOTSUPP is returned.
+       - Enable ATTR_SIZE attribute changes in ntfs_setattr().  This completes
+         the initial implementation of file truncation.  Now both open(2)ing
+         a file with the O_TRUNC flag and the {,f}truncate(2) system calls
+         will resize a file appropriately.  The limitations are that only
+         uncompressed and unencrypted files are supported.  Also, there is
+         only very limited support for highly fragmented files (the ones whose
+         $DATA attribute is split into multiple attribute extents).
+       - In attrib.c::ntfs_attr_set() call balance_dirty_pages_ratelimited()
+         and cond_resched() in the main loop as we could be dirtying a lot of
+         pages and this ensures we play nice with the VM and the system as a
+         whole.
+       - Implement file operations ->write, ->aio_write, ->writev for regular
+         files.  This replaces the old use of generic_file_write(), et al and
+         the address space operations ->prepare_write and ->commit_write.
+         This means that both sparse and non-sparse (unencrypted and
+         uncompressed) files can now be extended using the normal write(2)
+         code path.  There are two limitations at present and these are that
+         we never create sparse files and that we only have limited support
+         for highly fragmented files, i.e. ones whose data attribute is split
+         across multiple extents.   When such a case is encountered,
+         EOPNOTSUPP is returned.
+
 2.1.24 - Lots of bug fixes and support more clean journal states.
 
        - Support journals ($LogFile) which have been modified by chkdsk.  This
index 894b2b876d353b5c61a81e30d39ef608993f9000..d0d45d1c853a95f495755d9339b92f23b489ee13 100644 (file)
@@ -6,7 +6,7 @@ ntfs-objs := aops.o attrib.o collate.o compress.o debug.o dir.o file.o \
             index.o inode.o mft.o mst.o namei.o runlist.o super.o sysctl.o \
             unistr.o upcase.o
 
-EXTRA_CFLAGS = -DNTFS_VERSION=\"2.1.24\"
+EXTRA_CFLAGS = -DNTFS_VERSION=\"2.1.25\"
 
 ifeq ($(CONFIG_NTFS_DEBUG),y)
 EXTRA_CFLAGS += -DDEBUG
index 5e80c07c6a4d2b0a9c141602efeac6f9b5b59614..8f23c60030c010e59a8616488c1a344eeec36662 100644 (file)
@@ -1542,830 +1542,6 @@ err_out:
        return err;
 }
 
-/**
- * ntfs_prepare_nonresident_write -
- *
- */
-static int ntfs_prepare_nonresident_write(struct page *page,
-               unsigned from, unsigned to)
-{
-       VCN vcn;
-       LCN lcn;
-       s64 initialized_size;
-       loff_t i_size;
-       sector_t block, ablock, iblock;
-       struct inode *vi;
-       ntfs_inode *ni;
-       ntfs_volume *vol;
-       runlist_element *rl;
-       struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
-       unsigned long flags;
-       unsigned int vcn_ofs, block_start, block_end, blocksize;
-       int err;
-       BOOL is_retry;
-       unsigned char blocksize_bits;
-
-       vi = page->mapping->host;
-       ni = NTFS_I(vi);
-       vol = ni->vol;
-
-       ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
-                       "0x%lx, from = %u, to = %u.", ni->mft_no, ni->type,
-                       page->index, from, to);
-
-       BUG_ON(!NInoNonResident(ni));
-
-       blocksize_bits = vi->i_blkbits;
-       blocksize = 1 << blocksize_bits;
-
-       /*
-        * create_empty_buffers() will create uptodate/dirty buffers if the
-        * page is uptodate/dirty.
-        */
-       if (!page_has_buffers(page))
-               create_empty_buffers(page, blocksize, 0);
-       bh = head = page_buffers(page);
-       if (unlikely(!bh))
-               return -ENOMEM;
-
-       /* The first block in the page. */
-       block = (s64)page->index << (PAGE_CACHE_SHIFT - blocksize_bits);
-
-       read_lock_irqsave(&ni->size_lock, flags);
-       /*
-        * The first out of bounds block for the allocated size.  No need to
-        * round up as allocated_size is in multiples of cluster size and the
-        * minimum cluster size is 512 bytes, which is equal to the smallest
-        * blocksize.
-        */
-       ablock = ni->allocated_size >> blocksize_bits;
-       i_size = i_size_read(vi);
-       initialized_size = ni->initialized_size;
-       read_unlock_irqrestore(&ni->size_lock, flags);
-
-       /* The last (fully or partially) initialized block. */
-       iblock = initialized_size >> blocksize_bits;
-
-       /* Loop through all the buffers in the page. */
-       block_start = 0;
-       rl = NULL;
-       err = 0;
-       do {
-               block_end = block_start + blocksize;
-               /*
-                * If buffer @bh is outside the write, just mark it uptodate
-                * if the page is uptodate and continue with the next buffer.
-                */
-               if (block_end <= from || block_start >= to) {
-                       if (PageUptodate(page)) {
-                               if (!buffer_uptodate(bh))
-                                       set_buffer_uptodate(bh);
-                       }
-                       continue;
-               }
-               /*
-                * @bh is at least partially being written to.
-                * Make sure it is not marked as new.
-                */
-               //if (buffer_new(bh))
-               //      clear_buffer_new(bh);
-
-               if (block >= ablock) {
-                       // TODO: block is above allocated_size, need to
-                       // allocate it. Best done in one go to accommodate not
-                       // only block but all above blocks up to and including:
-                       // ((page->index << PAGE_CACHE_SHIFT) + to + blocksize
-                       // - 1) >> blobksize_bits. Obviously will need to round
-                       // up to next cluster boundary, too. This should be
-                       // done with a helper function, so it can be reused.
-                       ntfs_error(vol->sb, "Writing beyond allocated size "
-                                       "is not supported yet. Sorry.");
-                       err = -EOPNOTSUPP;
-                       goto err_out;
-                       // Need to update ablock.
-                       // Need to set_buffer_new() on all block bhs that are
-                       // newly allocated.
-               }
-               /*
-                * Now we have enough allocated size to fulfill the whole
-                * request, i.e. block < ablock is true.
-                */
-               if (unlikely((block >= iblock) &&
-                               (initialized_size < i_size))) {
-                       /*
-                        * If this page is fully outside initialized size, zero
-                        * out all pages between the current initialized size
-                        * and the current page. Just use ntfs_readpage() to do
-                        * the zeroing transparently.
-                        */
-                       if (block > iblock) {
-                               // TODO:
-                               // For each page do:
-                               // - read_cache_page()
-                               // Again for each page do:
-                               // - wait_on_page_locked()
-                               // - Check (PageUptodate(page) &&
-                               //                      !PageError(page))
-                               // Update initialized size in the attribute and
-                               // in the inode.
-                               // Again, for each page do:
-                               //      __set_page_dirty_buffers();
-                               // page_cache_release()
-                               // We don't need to wait on the writes.
-                               // Update iblock.
-                       }
-                       /*
-                        * The current page straddles initialized size. Zero
-                        * all non-uptodate buffers and set them uptodate (and
-                        * dirty?). Note, there aren't any non-uptodate buffers
-                        * if the page is uptodate.
-                        * FIXME: For an uptodate page, the buffers may need to
-                        * be written out because they were not initialized on
-                        * disk before.
-                        */
-                       if (!PageUptodate(page)) {
-                               // TODO:
-                               // Zero any non-uptodate buffers up to i_size.
-                               // Set them uptodate and dirty.
-                       }
-                       // TODO:
-                       // Update initialized size in the attribute and in the
-                       // inode (up to i_size).
-                       // Update iblock.
-                       // FIXME: This is inefficient. Try to batch the two
-                       // size changes to happen in one go.
-                       ntfs_error(vol->sb, "Writing beyond initialized size "
-                                       "is not supported yet. Sorry.");
-                       err = -EOPNOTSUPP;
-                       goto err_out;
-                       // Do NOT set_buffer_new() BUT DO clear buffer range
-                       // outside write request range.
-                       // set_buffer_uptodate() on complete buffers as well as
-                       // set_buffer_dirty().
-               }
-
-               /* Need to map unmapped buffers. */
-               if (!buffer_mapped(bh)) {
-                       /* Unmapped buffer. Need to map it. */
-                       bh->b_bdev = vol->sb->s_bdev;
-
-                       /* Convert block into corresponding vcn and offset. */
-                       vcn = (VCN)block << blocksize_bits >>
-                                       vol->cluster_size_bits;
-                       vcn_ofs = ((VCN)block << blocksize_bits) &
-                                       vol->cluster_size_mask;
-
-                       is_retry = FALSE;
-                       if (!rl) {
-lock_retry_remap:
-                               down_read(&ni->runlist.lock);
-                               rl = ni->runlist.rl;
-                       }
-                       if (likely(rl != NULL)) {
-                               /* Seek to element containing target vcn. */
-                               while (rl->length && rl[1].vcn <= vcn)
-                                       rl++;
-                               lcn = ntfs_rl_vcn_to_lcn(rl, vcn);
-                       } else
-                               lcn = LCN_RL_NOT_MAPPED;
-                       if (unlikely(lcn < 0)) {
-                               /*
-                                * We extended the attribute allocation above.
-                                * If we hit an ENOENT here it means that the
-                                * allocation was insufficient which is a bug.
-                                */
-                               BUG_ON(lcn == LCN_ENOENT);
-
-                               /* It is a hole, need to instantiate it. */
-                               if (lcn == LCN_HOLE) {
-                                       // TODO: Instantiate the hole.
-                                       // clear_buffer_new(bh);
-                                       // unmap_underlying_metadata(bh->b_bdev,
-                                       //              bh->b_blocknr);
-                                       // For non-uptodate buffers, need to
-                                       // zero out the region outside the
-                                       // request in this bh or all bhs,
-                                       // depending on what we implemented
-                                       // above.
-                                       // Need to flush_dcache_page().
-                                       // Or could use set_buffer_new()
-                                       // instead?
-                                       ntfs_error(vol->sb, "Writing into "
-                                                       "sparse regions is "
-                                                       "not supported yet. "
-                                                       "Sorry.");
-                                       err = -EOPNOTSUPP;
-                                       if (!rl)
-                                               up_read(&ni->runlist.lock);
-                                       goto err_out;
-                               } else if (!is_retry &&
-                                               lcn == LCN_RL_NOT_MAPPED) {
-                                       is_retry = TRUE;
-                                       /*
-                                        * Attempt to map runlist, dropping
-                                        * lock for the duration.
-                                        */
-                                       up_read(&ni->runlist.lock);
-                                       err = ntfs_map_runlist(ni, vcn);
-                                       if (likely(!err))
-                                               goto lock_retry_remap;
-                                       rl = NULL;
-                               } else if (!rl)
-                                       up_read(&ni->runlist.lock);
-                               /*
-                                * Failed to map the buffer, even after
-                                * retrying.
-                                */
-                               if (!err)
-                                       err = -EIO;
-                               bh->b_blocknr = -1;
-                               ntfs_error(vol->sb, "Failed to write to inode "
-                                               "0x%lx, attribute type 0x%x, "
-                                               "vcn 0x%llx, offset 0x%x "
-                                               "because its location on disk "
-                                               "could not be determined%s "
-                                               "(error code %i).",
-                                               ni->mft_no, ni->type,
-                                               (unsigned long long)vcn,
-                                               vcn_ofs, is_retry ? " even "
-                                               "after retrying" : "", err);
-                               goto err_out;
-                       }
-                       /* We now have a successful remap, i.e. lcn >= 0. */
-
-                       /* Setup buffer head to correct block. */
-                       bh->b_blocknr = ((lcn << vol->cluster_size_bits)
-                                       + vcn_ofs) >> blocksize_bits;
-                       set_buffer_mapped(bh);
-
-                       // FIXME: Something analogous to this is needed for
-                       // each newly allocated block, i.e. BH_New.
-                       // FIXME: Might need to take this out of the
-                       // if (!buffer_mapped(bh)) {}, depending on how we
-                       // implement things during the allocated_size and
-                       // initialized_size extension code above.
-                       if (buffer_new(bh)) {
-                               clear_buffer_new(bh);
-                               unmap_underlying_metadata(bh->b_bdev,
-                                               bh->b_blocknr);
-                               if (PageUptodate(page)) {
-                                       set_buffer_uptodate(bh);
-                                       continue;
-                               }
-                               /*
-                                * Page is _not_ uptodate, zero surrounding
-                                * region. NOTE: This is how we decide if to
-                                * zero or not!
-                                */
-                               if (block_end > to || block_start < from) {
-                                       void *kaddr;
-
-                                       kaddr = kmap_atomic(page, KM_USER0);
-                                       if (block_end > to)
-                                               memset(kaddr + to, 0,
-                                                               block_end - to);
-                                       if (block_start < from)
-                                               memset(kaddr + block_start, 0,
-                                                               from -
-                                                               block_start);
-                                       flush_dcache_page(page);
-                                       kunmap_atomic(kaddr, KM_USER0);
-                               }
-                               continue;
-                       }
-               }
-               /* @bh is mapped, set it uptodate if the page is uptodate. */
-               if (PageUptodate(page)) {
-                       if (!buffer_uptodate(bh))
-                               set_buffer_uptodate(bh);
-                       continue;
-               }
-               /*
-                * The page is not uptodate. The buffer is mapped. If it is not
-                * uptodate, and it is only partially being written to, we need
-                * to read the buffer in before the write, i.e. right now.
-                */
-               if (!buffer_uptodate(bh) &&
-                               (block_start < from || block_end > to)) {
-                       ll_rw_block(READ, 1, &bh);
-                       *wait_bh++ = bh;
-               }
-       } while (block++, block_start = block_end,
-                       (bh = bh->b_this_page) != head);
-
-       /* Release the lock if we took it. */
-       if (rl) {
-               up_read(&ni->runlist.lock);
-               rl = NULL;
-       }
-
-       /* If we issued read requests, let them complete. */
-       while (wait_bh > wait) {
-               wait_on_buffer(*--wait_bh);
-               if (!buffer_uptodate(*wait_bh))
-                       return -EIO;
-       }
-
-       ntfs_debug("Done.");
-       return 0;
-err_out:
-       /*
-        * Zero out any newly allocated blocks to avoid exposing stale data.
-        * If BH_New is set, we know that the block was newly allocated in the
-        * above loop.
-        * FIXME: What about initialized_size increments? Have we done all the
-        * required zeroing above? If not this error handling is broken, and
-        * in particular the if (block_end <= from) check is completely bogus.
-        */
-       bh = head;
-       block_start = 0;
-       is_retry = FALSE;
-       do {
-               block_end = block_start + blocksize;
-               if (block_end <= from)
-                       continue;
-               if (block_start >= to)
-                       break;
-               if (buffer_new(bh)) {
-                       void *kaddr;
-
-                       clear_buffer_new(bh);
-                       kaddr = kmap_atomic(page, KM_USER0);
-                       memset(kaddr + block_start, 0, bh->b_size);
-                       kunmap_atomic(kaddr, KM_USER0);
-                       set_buffer_uptodate(bh);
-                       mark_buffer_dirty(bh);
-                       is_retry = TRUE;
-               }
-       } while (block_start = block_end, (bh = bh->b_this_page) != head);
-       if (is_retry)
-               flush_dcache_page(page);
-       if (rl)
-               up_read(&ni->runlist.lock);
-       return err;
-}
-
-/**
- * ntfs_prepare_write - prepare a page for receiving data
- *
- * This is called from generic_file_write() with i_sem held on the inode
- * (@page->mapping->host).  The @page is locked but not kmap()ped.  The source
- * data has not yet been copied into the @page.
- *
- * Need to extend the attribute/fill in holes if necessary, create blocks and
- * make partially overwritten blocks uptodate,
- *
- * i_size is not to be modified yet.
- *
- * Return 0 on success or -errno on error.
- *
- * Should be using block_prepare_write() [support for sparse files] or
- * cont_prepare_write() [no support for sparse files].  Cannot do that due to
- * ntfs specifics but can look at them for implementation guidance.
- *
- * Note: In the range, @from is inclusive and @to is exclusive, i.e. @from is
- * the first byte in the page that will be written to and @to is the first byte
- * after the last byte that will be written to.
- */
-static int ntfs_prepare_write(struct file *file, struct page *page,
-               unsigned from, unsigned to)
-{
-       s64 new_size;
-       loff_t i_size;
-       struct inode *vi = page->mapping->host;
-       ntfs_inode *base_ni = NULL, *ni = NTFS_I(vi);
-       ntfs_volume *vol = ni->vol;
-       ntfs_attr_search_ctx *ctx = NULL;
-       MFT_RECORD *m = NULL;
-       ATTR_RECORD *a;
-       u8 *kaddr;
-       u32 attr_len;
-       int err;
-
-       ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
-                       "0x%lx, from = %u, to = %u.", vi->i_ino, ni->type,
-                       page->index, from, to);
-       BUG_ON(!PageLocked(page));
-       BUG_ON(from > PAGE_CACHE_SIZE);
-       BUG_ON(to > PAGE_CACHE_SIZE);
-       BUG_ON(from > to);
-       BUG_ON(NInoMstProtected(ni));
-       /*
-        * If a previous ntfs_truncate() failed, repeat it and abort if it
-        * fails again.
-        */
-       if (unlikely(NInoTruncateFailed(ni))) {
-               down_write(&vi->i_alloc_sem);
-               err = ntfs_truncate(vi);
-               up_write(&vi->i_alloc_sem);
-               if (err || NInoTruncateFailed(ni)) {
-                       if (!err)
-                               err = -EIO;
-                       goto err_out;
-               }
-       }
-       /* If the attribute is not resident, deal with it elsewhere. */
-       if (NInoNonResident(ni)) {
-               /*
-                * Only unnamed $DATA attributes can be compressed, encrypted,
-                * and/or sparse.
-                */
-               if (ni->type == AT_DATA && !ni->name_len) {
-                       /* If file is encrypted, deny access, just like NT4. */
-                       if (NInoEncrypted(ni)) {
-                               ntfs_debug("Denying write access to encrypted "
-                                               "file.");
-                               return -EACCES;
-                       }
-                       /* Compressed data streams are handled in compress.c. */
-                       if (NInoCompressed(ni)) {
-                               // TODO: Implement and replace this check with
-                               // return ntfs_write_compressed_block(page);
-                               ntfs_error(vi->i_sb, "Writing to compressed "
-                                               "files is not supported yet. "
-                                               "Sorry.");
-                               return -EOPNOTSUPP;
-                       }
-                       // TODO: Implement and remove this check.
-                       if (NInoSparse(ni)) {
-                               ntfs_error(vi->i_sb, "Writing to sparse files "
-                                               "is not supported yet. Sorry.");
-                               return -EOPNOTSUPP;
-                       }
-               }
-               /* Normal data stream. */
-               return ntfs_prepare_nonresident_write(page, from, to);
-       }
-       /*
-        * Attribute is resident, implying it is not compressed, encrypted, or
-        * sparse.
-        */
-       BUG_ON(page_has_buffers(page));
-       new_size = ((s64)page->index << PAGE_CACHE_SHIFT) + to;
-       /* If we do not need to resize the attribute allocation we are done. */
-       if (new_size <= i_size_read(vi))
-               goto done;
-       /* Map, pin, and lock the (base) mft record. */
-       if (!NInoAttr(ni))
-               base_ni = ni;
-       else
-               base_ni = ni->ext.base_ntfs_ino;
-       m = map_mft_record(base_ni);
-       if (IS_ERR(m)) {
-               err = PTR_ERR(m);
-               m = NULL;
-               ctx = NULL;
-               goto err_out;
-       }
-       ctx = ntfs_attr_get_search_ctx(base_ni, m);
-       if (unlikely(!ctx)) {
-               err = -ENOMEM;
-               goto err_out;
-       }
-       err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
-                       CASE_SENSITIVE, 0, NULL, 0, ctx);
-       if (unlikely(err)) {
-               if (err == -ENOENT)
-                       err = -EIO;
-               goto err_out;
-       }
-       m = ctx->mrec;
-       a = ctx->attr;
-       /* The total length of the attribute value. */
-       attr_len = le32_to_cpu(a->data.resident.value_length);
-       /* Fix an eventual previous failure of ntfs_commit_write(). */
-       i_size = i_size_read(vi);
-       if (unlikely(attr_len > i_size)) {
-               attr_len = i_size;
-               a->data.resident.value_length = cpu_to_le32(attr_len);
-       }
-       /* If we do not need to resize the attribute allocation we are done. */
-       if (new_size <= attr_len)
-               goto done_unm;
-       /* Check if new size is allowed in $AttrDef. */
-       err = ntfs_attr_size_bounds_check(vol, ni->type, new_size);
-       if (unlikely(err)) {
-               if (err == -ERANGE) {
-                       ntfs_error(vol->sb, "Write would cause the inode "
-                                       "0x%lx to exceed the maximum size for "
-                                       "its attribute type (0x%x).  Aborting "
-                                       "write.", vi->i_ino,
-                                       le32_to_cpu(ni->type));
-               } else {
-                       ntfs_error(vol->sb, "Inode 0x%lx has unknown "
-                                       "attribute type 0x%x.  Aborting "
-                                       "write.", vi->i_ino,
-                                       le32_to_cpu(ni->type));
-                       err = -EIO;
-               }
-               goto err_out2;
-       }
-       /*
-        * Extend the attribute record to be able to store the new attribute
-        * size.
-        */
-       if (new_size >= vol->mft_record_size || ntfs_attr_record_resize(m, a,
-                       le16_to_cpu(a->data.resident.value_offset) +
-                       new_size)) {
-               /* Not enough space in the mft record. */
-               ntfs_error(vol->sb, "Not enough space in the mft record for "
-                               "the resized attribute value.  This is not "
-                               "supported yet.  Aborting write.");
-               err = -EOPNOTSUPP;
-               goto err_out2;
-       }
-       /*
-        * We have enough space in the mft record to fit the write.  This
-        * implies the attribute is smaller than the mft record and hence the
-        * attribute must be in a single page and hence page->index must be 0.
-        */
-       BUG_ON(page->index);
-       /*
-        * If the beginning of the write is past the old size, enlarge the
-        * attribute value up to the beginning of the write and fill it with
-        * zeroes.
-        */
-       if (from > attr_len) {
-               memset((u8*)a + le16_to_cpu(a->data.resident.value_offset) +
-                               attr_len, 0, from - attr_len);
-               a->data.resident.value_length = cpu_to_le32(from);
-               /* Zero the corresponding area in the page as well. */
-               if (PageUptodate(page)) {
-                       kaddr = kmap_atomic(page, KM_USER0);
-                       memset(kaddr + attr_len, 0, from - attr_len);
-                       kunmap_atomic(kaddr, KM_USER0);
-                       flush_dcache_page(page);
-               }
-       }
-       flush_dcache_mft_record_page(ctx->ntfs_ino);
-       mark_mft_record_dirty(ctx->ntfs_ino);
-done_unm:
-       ntfs_attr_put_search_ctx(ctx);
-       unmap_mft_record(base_ni);
-       /*
-        * Because resident attributes are handled by memcpy() to/from the
-        * corresponding MFT record, and because this form of i/o is byte
-        * aligned rather than block aligned, there is no need to bring the
-        * page uptodate here as in the non-resident case where we need to
-        * bring the buffers straddled by the write uptodate before
-        * generic_file_write() does the copying from userspace.
-        *
-        * We thus defer the uptodate bringing of the page region outside the
-        * region written to to ntfs_commit_write(), which makes the code
-        * simpler and saves one atomic kmap which is good.
-        */
-done:
-       ntfs_debug("Done.");
-       return 0;
-err_out:
-       if (err == -ENOMEM)
-               ntfs_warning(vi->i_sb, "Error allocating memory required to "
-                               "prepare the write.");
-       else {
-               ntfs_error(vi->i_sb, "Resident attribute prepare write failed "
-                               "with error %i.", err);
-               NVolSetErrors(vol);
-               make_bad_inode(vi);
-       }
-err_out2:
-       if (ctx)
-               ntfs_attr_put_search_ctx(ctx);
-       if (m)
-               unmap_mft_record(base_ni);
-       return err;
-}
-
-/**
- * ntfs_commit_nonresident_write -
- *
- */
-static int ntfs_commit_nonresident_write(struct page *page,
-               unsigned from, unsigned to)
-{
-       s64 pos = ((s64)page->index << PAGE_CACHE_SHIFT) + to;
-       struct inode *vi = page->mapping->host;
-       struct buffer_head *bh, *head;
-       unsigned int block_start, block_end, blocksize;
-       BOOL partial;
-
-       ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
-                       "0x%lx, from = %u, to = %u.", vi->i_ino,
-                       NTFS_I(vi)->type, page->index, from, to);
-       blocksize = 1 << vi->i_blkbits;
-
-       // FIXME: We need a whole slew of special cases in here for compressed
-       // files for example...
-       // For now, we know ntfs_prepare_write() would have failed so we can't
-       // get here in any of the cases which we have to special case, so we
-       // are just a ripped off, unrolled generic_commit_write().
-
-       bh = head = page_buffers(page);
-       block_start = 0;
-       partial = FALSE;
-       do {
-               block_end = block_start + blocksize;
-               if (block_end <= from || block_start >= to) {
-                       if (!buffer_uptodate(bh))
-                               partial = TRUE;
-               } else {
-                       set_buffer_uptodate(bh);
-                       mark_buffer_dirty(bh);
-               }
-       } while (block_start = block_end, (bh = bh->b_this_page) != head);
-       /*
-        * If this is a partial write which happened to make all buffers
-        * uptodate then we can optimize away a bogus ->readpage() for the next
-        * read().  Here we 'discover' whether the page went uptodate as a
-        * result of this (potentially partial) write.
-        */
-       if (!partial)
-               SetPageUptodate(page);
-       /*
-        * Not convinced about this at all.  See disparity comment above.  For
-        * now we know ntfs_prepare_write() would have failed in the write
-        * exceeds i_size case, so this will never trigger which is fine.
-        */
-       if (pos > i_size_read(vi)) {
-               ntfs_error(vi->i_sb, "Writing beyond the existing file size is "
-                               "not supported yet.  Sorry.");
-               return -EOPNOTSUPP;
-               // vi->i_size = pos;
-               // mark_inode_dirty(vi);
-       }
-       ntfs_debug("Done.");
-       return 0;
-}
-
-/**
- * ntfs_commit_write - commit the received data
- *
- * This is called from generic_file_write() with i_sem held on the inode
- * (@page->mapping->host).  The @page is locked but not kmap()ped.  The source
- * data has already been copied into the @page.  ntfs_prepare_write() has been
- * called before the data copied and it returned success so we can take the
- * results of various BUG checks and some error handling for granted.
- *
- * Need to mark modified blocks dirty so they get written out later when
- * ntfs_writepage() is invoked by the VM.
- *
- * Return 0 on success or -errno on error.
- *
- * Should be using generic_commit_write().  This marks buffers uptodate and
- * dirty, sets the page uptodate if all buffers in the page are uptodate, and
- * updates i_size if the end of io is beyond i_size.  In that case, it also
- * marks the inode dirty.
- *
- * Cannot use generic_commit_write() due to ntfs specialities but can look at
- * it for implementation guidance.
- *
- * If things have gone as outlined in ntfs_prepare_write(), then we do not
- * need to do any page content modifications here at all, except in the write
- * to resident attribute case, where we need to do the uptodate bringing here
- * which we combine with the copying into the mft record which means we save
- * one atomic kmap.
- */
-static int ntfs_commit_write(struct file *file, struct page *page,
-               unsigned from, unsigned to)
-{
-       struct inode *vi = page->mapping->host;
-       ntfs_inode *base_ni, *ni = NTFS_I(vi);
-       char *kaddr, *kattr;
-       ntfs_attr_search_ctx *ctx;
-       MFT_RECORD *m;
-       ATTR_RECORD *a;
-       u32 attr_len;
-       int err;
-
-       ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
-                       "0x%lx, from = %u, to = %u.", vi->i_ino, ni->type,
-                       page->index, from, to);
-       /* If the attribute is not resident, deal with it elsewhere. */
-       if (NInoNonResident(ni)) {
-               /* Only unnamed $DATA attributes can be compressed/encrypted. */
-               if (ni->type == AT_DATA && !ni->name_len) {
-                       /* Encrypted files need separate handling. */
-                       if (NInoEncrypted(ni)) {
-                               // We never get here at present!
-                               BUG();
-                       }
-                       /* Compressed data streams are handled in compress.c. */
-                       if (NInoCompressed(ni)) {
-                               // TODO: Implement this!
-                               // return ntfs_write_compressed_block(page);
-                               // We never get here at present!
-                               BUG();
-                       }
-               }
-               /* Normal data stream. */
-               return ntfs_commit_nonresident_write(page, from, to);
-       }
-       /*
-        * Attribute is resident, implying it is not compressed, encrypted, or
-        * sparse.
-        */
-       if (!NInoAttr(ni))
-               base_ni = ni;
-       else
-               base_ni = ni->ext.base_ntfs_ino;
-       /* Map, pin, and lock the mft record. */
-       m = map_mft_record(base_ni);
-       if (IS_ERR(m)) {
-               err = PTR_ERR(m);
-               m = NULL;
-               ctx = NULL;
-               goto err_out;
-       }
-       ctx = ntfs_attr_get_search_ctx(base_ni, m);
-       if (unlikely(!ctx)) {
-               err = -ENOMEM;
-               goto err_out;
-       }
-       err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
-                       CASE_SENSITIVE, 0, NULL, 0, ctx);
-       if (unlikely(err)) {
-               if (err == -ENOENT)
-                       err = -EIO;
-               goto err_out;
-       }
-       a = ctx->attr;
-       /* The total length of the attribute value. */
-       attr_len = le32_to_cpu(a->data.resident.value_length);
-       BUG_ON(from > attr_len);
-       kattr = (u8*)a + le16_to_cpu(a->data.resident.value_offset);
-       kaddr = kmap_atomic(page, KM_USER0);
-       /* Copy the received data from the page to the mft record. */
-       memcpy(kattr + from, kaddr + from, to - from);
-       /* Update the attribute length if necessary. */
-       if (to > attr_len) {
-               attr_len = to;
-               a->data.resident.value_length = cpu_to_le32(attr_len);
-       }
-       /*
-        * If the page is not uptodate, bring the out of bounds area(s)
-        * uptodate by copying data from the mft record to the page.
-        */
-       if (!PageUptodate(page)) {
-               if (from > 0)
-                       memcpy(kaddr, kattr, from);
-               if (to < attr_len)
-                       memcpy(kaddr + to, kattr + to, attr_len - to);
-               /* Zero the region outside the end of the attribute value. */
-               if (attr_len < PAGE_CACHE_SIZE)
-                       memset(kaddr + attr_len, 0, PAGE_CACHE_SIZE - attr_len);
-               /*
-                * The probability of not having done any of the above is
-                * extremely small, so we just flush unconditionally.
-                */
-               flush_dcache_page(page);
-               SetPageUptodate(page);
-       }
-       kunmap_atomic(kaddr, KM_USER0);
-       /* Update i_size if necessary. */
-       if (i_size_read(vi) < attr_len) {
-               unsigned long flags;
-
-               write_lock_irqsave(&ni->size_lock, flags);
-               ni->allocated_size = ni->initialized_size = attr_len;
-               i_size_write(vi, attr_len);
-               write_unlock_irqrestore(&ni->size_lock, flags);
-       }
-       /* Mark the mft record dirty, so it gets written back. */
-       flush_dcache_mft_record_page(ctx->ntfs_ino);
-       mark_mft_record_dirty(ctx->ntfs_ino);
-       ntfs_attr_put_search_ctx(ctx);
-       unmap_mft_record(base_ni);
-       ntfs_debug("Done.");
-       return 0;
-err_out:
-       if (err == -ENOMEM) {
-               ntfs_warning(vi->i_sb, "Error allocating memory required to "
-                               "commit the write.");
-               if (PageUptodate(page)) {
-                       ntfs_warning(vi->i_sb, "Page is uptodate, setting "
-                                       "dirty so the write will be retried "
-                                       "later on by the VM.");
-                       /*
-                        * Put the page on mapping->dirty_pages, but leave its
-                        * buffers' dirty state as-is.
-                        */
-                       __set_page_dirty_nobuffers(page);
-                       err = 0;
-               } else
-                       ntfs_error(vi->i_sb, "Page is not uptodate.  Written "
-                                       "data has been lost.");
-       } else {
-               ntfs_error(vi->i_sb, "Resident attribute commit write failed "
-                               "with error %i.", err);
-               NVolSetErrors(ni->vol);
-               make_bad_inode(vi);
-       }
-       if (ctx)
-               ntfs_attr_put_search_ctx(ctx);
-       if (m)
-               unmap_mft_record(base_ni);
-       return err;
-}
-
 #endif /* NTFS_RW */
 
 /**
@@ -2377,9 +1553,6 @@ struct address_space_operations ntfs_aops = {
                                                   disk request queue. */
 #ifdef NTFS_RW
        .writepage      = ntfs_writepage,       /* Write dirty page to disk. */
-       .prepare_write  = ntfs_prepare_write,   /* Prepare page and buffers
-                                                  ready to receive data. */
-       .commit_write   = ntfs_commit_write,    /* Commit received data. */
 #endif /* NTFS_RW */
 };
 
index 3f9a4ff42ee51b07b75e57691997087df11a181d..338e47144fc950e049fb13b855f3e759e95a1743 100644 (file)
@@ -21,7 +21,9 @@
  */
 
 #include <linux/buffer_head.h>
+#include <linux/sched.h>
 #include <linux/swap.h>
+#include <linux/writeback.h>
 
 #include "attrib.h"
 #include "debug.h"
  * ntfs_map_runlist_nolock - map (a part of) a runlist of an ntfs inode
  * @ni:                ntfs inode for which to map (part of) a runlist
  * @vcn:       map runlist part containing this vcn
+ * @ctx:       active attribute search context if present or NULL if not
  *
  * Map the part of a runlist containing the @vcn of the ntfs inode @ni.
  *
+ * If @ctx is specified, it is an active search context of @ni and its base mft
+ * record.  This is needed when ntfs_map_runlist_nolock() encounters unmapped
+ * runlist fragments and allows their mapping.  If you do not have the mft
+ * record mapped, you can specify @ctx as NULL and ntfs_map_runlist_nolock()
+ * will perform the necessary mapping and unmapping.
+ *
+ * Note, ntfs_map_runlist_nolock() saves the state of @ctx on entry and
+ * restores it before returning.  Thus, @ctx will be left pointing to the same
+ * attribute on return as on entry.  However, the actual pointers in @ctx may
+ * point to different memory locations on return, so you must remember to reset
+ * any cached pointers from the @ctx, i.e. after the call to
+ * ntfs_map_runlist_nolock(), you will probably want to do:
+ *     m = ctx->mrec;
+ *     a = ctx->attr;
+ * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
+ * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
+ *
  * Return 0 on success and -errno on error.  There is one special error code
  * which is not an error as such.  This is -ENOENT.  It means that @vcn is out
  * of bounds of the runlist.
  * Note the runlist can be NULL after this function returns if @vcn is zero and
  * the attribute has zero allocated size, i.e. there simply is no runlist.
  *
- * Locking: - The runlist must be locked for writing.
- *         - This function modifies the runlist.
+ * WARNING: If @ctx is supplied, regardless of whether success or failure is
+ *         returned, you need to check IS_ERR(@ctx->mrec) and if TRUE the @ctx
+ *         is no longer valid, i.e. you need to either call
+ *         ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
+ *         In that case PTR_ERR(@ctx->mrec) will give you the error code for
+ *         why the mapping of the old inode failed.
+ *
+ * Locking: - The runlist described by @ni must be locked for writing on entry
+ *           and is locked on return.  Note the runlist will be modified.
+ *         - If @ctx is NULL, the base mft record of @ni must not be mapped on
+ *           entry and it will be left unmapped on return.
+ *         - If @ctx is not NULL, the base mft record must be mapped on entry
+ *           and it will be left mapped on return.
  */
-int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
+int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn, ntfs_attr_search_ctx *ctx)
 {
        VCN end_vcn;
+       unsigned long flags;
        ntfs_inode *base_ni;
        MFT_RECORD *m;
        ATTR_RECORD *a;
-       ntfs_attr_search_ctx *ctx;
        runlist_element *rl;
-       unsigned long flags;
+       struct page *put_this_page = NULL;
        int err = 0;
+       BOOL ctx_is_temporary, ctx_needs_reset;
+       ntfs_attr_search_ctx old_ctx;
 
        ntfs_debug("Mapping runlist part containing vcn 0x%llx.",
                        (unsigned long long)vcn);
@@ -66,20 +99,77 @@ int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
                base_ni = ni;
        else
                base_ni = ni->ext.base_ntfs_ino;
-       m = map_mft_record(base_ni);
-       if (IS_ERR(m))
-               return PTR_ERR(m);
-       ctx = ntfs_attr_get_search_ctx(base_ni, m);
-       if (unlikely(!ctx)) {
-               err = -ENOMEM;
-               goto err_out;
+       if (!ctx) {
+               ctx_is_temporary = ctx_needs_reset = TRUE;
+               m = map_mft_record(base_ni);
+               if (IS_ERR(m))
+                       return PTR_ERR(m);
+               ctx = ntfs_attr_get_search_ctx(base_ni, m);
+               if (unlikely(!ctx)) {
+                       err = -ENOMEM;
+                       goto err_out;
+               }
+       } else {
+               VCN allocated_size_vcn;
+
+               BUG_ON(IS_ERR(ctx->mrec));
+               a = ctx->attr;
+               BUG_ON(!a->non_resident);
+               ctx_is_temporary = FALSE;
+               end_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn);
+               read_lock_irqsave(&ni->size_lock, flags);
+               allocated_size_vcn = ni->allocated_size >>
+                               ni->vol->cluster_size_bits;
+               read_unlock_irqrestore(&ni->size_lock, flags);
+               if (!a->data.non_resident.lowest_vcn && end_vcn <= 0)
+                       end_vcn = allocated_size_vcn - 1;
+               /*
+                * If we already have the attribute extent containing @vcn in
+                * @ctx, no need to look it up again.  We slightly cheat in
+                * that if vcn exceeds the allocated size, we will refuse to
+                * map the runlist below, so there is definitely no need to get
+                * the right attribute extent.
+                */
+               if (vcn >= allocated_size_vcn || (a->type == ni->type &&
+                               a->name_length == ni->name_len &&
+                               !memcmp((u8*)a + le16_to_cpu(a->name_offset),
+                               ni->name, ni->name_len) &&
+                               sle64_to_cpu(a->data.non_resident.lowest_vcn)
+                               <= vcn && end_vcn >= vcn))
+                       ctx_needs_reset = FALSE;
+               else {
+                       /* Save the old search context. */
+                       old_ctx = *ctx;
+                       /*
+                        * If the currently mapped (extent) inode is not the
+                        * base inode we will unmap it when we reinitialize the
+                        * search context which means we need to get a
+                        * reference to the page containing the mapped mft
+                        * record so we do not accidentally drop changes to the
+                        * mft record when it has not been marked dirty yet.
+                        */
+                       if (old_ctx.base_ntfs_ino && old_ctx.ntfs_ino !=
+                                       old_ctx.base_ntfs_ino) {
+                               put_this_page = old_ctx.ntfs_ino->page;
+                               page_cache_get(put_this_page);
+                       }
+                       /*
+                        * Reinitialize the search context so we can lookup the
+                        * needed attribute extent.
+                        */
+                       ntfs_attr_reinit_search_ctx(ctx);
+                       ctx_needs_reset = TRUE;
+               }
        }
-       err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
-                       CASE_SENSITIVE, vcn, NULL, 0, ctx);
-       if (unlikely(err)) {
-               if (err == -ENOENT)
-                       err = -EIO;
-               goto err_out;
+       if (ctx_needs_reset) {
+               err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+                               CASE_SENSITIVE, vcn, NULL, 0, ctx);
+               if (unlikely(err)) {
+                       if (err == -ENOENT)
+                               err = -EIO;
+                       goto err_out;
+               }
+               BUG_ON(!ctx->attr->non_resident);
        }
        a = ctx->attr;
        /*
@@ -89,11 +179,9 @@ int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
         * ntfs_mapping_pairs_decompress() fails.
         */
        end_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn) + 1;
-       if (unlikely(!a->data.non_resident.lowest_vcn && end_vcn <= 1)) {
-               read_lock_irqsave(&ni->size_lock, flags);
-               end_vcn = ni->allocated_size >> ni->vol->cluster_size_bits;
-               read_unlock_irqrestore(&ni->size_lock, flags);
-       }
+       if (!a->data.non_resident.lowest_vcn && end_vcn == 1)
+               end_vcn = sle64_to_cpu(a->data.non_resident.allocated_size) >>
+                               ni->vol->cluster_size_bits;
        if (unlikely(vcn >= end_vcn)) {
                err = -ENOENT;
                goto err_out;
@@ -104,9 +192,93 @@ int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
        else
                ni->runlist.rl = rl;
 err_out:
-       if (likely(ctx))
-               ntfs_attr_put_search_ctx(ctx);
-       unmap_mft_record(base_ni);
+       if (ctx_is_temporary) {
+               if (likely(ctx))
+                       ntfs_attr_put_search_ctx(ctx);
+               unmap_mft_record(base_ni);
+       } else if (ctx_needs_reset) {
+               /*
+                * If there is no attribute list, restoring the search context
+                * is acomplished simply by copying the saved context back over
+                * the caller supplied context.  If there is an attribute list,
+                * things are more complicated as we need to deal with mapping
+                * of mft records and resulting potential changes in pointers.
+                */
+               if (NInoAttrList(base_ni)) {
+                       /*
+                        * If the currently mapped (extent) inode is not the
+                        * one we had before, we need to unmap it and map the
+                        * old one.
+                        */
+                       if (ctx->ntfs_ino != old_ctx.ntfs_ino) {
+                               /*
+                                * If the currently mapped inode is not the
+                                * base inode, unmap it.
+                                */
+                               if (ctx->base_ntfs_ino && ctx->ntfs_ino !=
+                                               ctx->base_ntfs_ino) {
+                                       unmap_extent_mft_record(ctx->ntfs_ino);
+                                       ctx->mrec = ctx->base_mrec;
+                                       BUG_ON(!ctx->mrec);
+                               }
+                               /*
+                                * If the old mapped inode is not the base
+                                * inode, map it.
+                                */
+                               if (old_ctx.base_ntfs_ino &&
+                                               old_ctx.ntfs_ino !=
+                                               old_ctx.base_ntfs_ino) {
+retry_map:
+                                       ctx->mrec = map_mft_record(
+                                                       old_ctx.ntfs_ino);
+                                       /*
+                                        * Something bad has happened.  If out
+                                        * of memory retry till it succeeds.
+                                        * Any other errors are fatal and we
+                                        * return the error code in ctx->mrec.
+                                        * Let the caller deal with it...  We
+                                        * just need to fudge things so the
+                                        * caller can reinit and/or put the
+                                        * search context safely.
+                                        */
+                                       if (IS_ERR(ctx->mrec)) {
+                                               if (PTR_ERR(ctx->mrec) ==
+                                                               -ENOMEM) {
+                                                       schedule();
+                                                       goto retry_map;
+                                               } else
+                                                       old_ctx.ntfs_ino =
+                                                               old_ctx.
+                                                               base_ntfs_ino;
+                                       }
+                               }
+                       }
+                       /* Update the changed pointers in the saved context. */
+                       if (ctx->mrec != old_ctx.mrec) {
+                               if (!IS_ERR(ctx->mrec))
+                                       old_ctx.attr = (ATTR_RECORD*)(
+                                                       (u8*)ctx->mrec +
+                                                       ((u8*)old_ctx.attr -
+                                                       (u8*)old_ctx.mrec));
+                               old_ctx.mrec = ctx->mrec;
+                       }
+               }
+               /* Restore the search context to the saved one. */
+               *ctx = old_ctx;
+               /*
+                * We drop the reference on the page we took earlier.  In the
+                * case that IS_ERR(ctx->mrec) is true this means we might lose
+                * some changes to the mft record that had been made between
+                * the last time it was marked dirty/written out and now.  This
+                * at this stage is not a problem as the mapping error is fatal
+                * enough that the mft record cannot be written out anyway and
+                * the caller is very likely to shutdown the whole inode
+                * immediately and mark the volume dirty for chkdsk to pick up
+                * the pieces anyway.
+                */
+               if (put_this_page)
+                       page_cache_release(put_this_page);
+       }
        return err;
 }
 
@@ -122,8 +294,8 @@ err_out:
  * of bounds of the runlist.
  *
  * Locking: - The runlist must be unlocked on entry and is unlocked on return.
- *         - This function takes the runlist lock for writing and modifies the
- *           runlist.
+ *         - This function takes the runlist lock for writing and may modify
+ *           the runlist.
  */
 int ntfs_map_runlist(ntfs_inode *ni, VCN vcn)
 {
@@ -133,7 +305,7 @@ int ntfs_map_runlist(ntfs_inode *ni, VCN vcn)
        /* Make sure someone else didn't do the work while we were sleeping. */
        if (likely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) <=
                        LCN_RL_NOT_MAPPED))
-               err = ntfs_map_runlist_nolock(ni, vcn);
+               err = ntfs_map_runlist_nolock(ni, vcn, NULL);
        up_write(&ni->runlist.lock);
        return err;
 }
@@ -212,7 +384,7 @@ retry_remap:
                                goto retry_remap;
                        }
                }
-               err = ntfs_map_runlist_nolock(ni, vcn);
+               err = ntfs_map_runlist_nolock(ni, vcn, NULL);
                if (!write_locked) {
                        up_write(&ni->runlist.lock);
                        down_read(&ni->runlist.lock);
@@ -236,9 +408,9 @@ retry_remap:
 
 /**
  * ntfs_attr_find_vcn_nolock - find a vcn in the runlist of an ntfs inode
- * @ni:                        ntfs inode describing the runlist to search
- * @vcn:               vcn to find
- * @write_locked:      true if the runlist is locked for writing
+ * @ni:                ntfs inode describing the runlist to search
+ * @vcn:       vcn to find
+ * @ctx:       active attribute search context if present or NULL if not
  *
  * Find the virtual cluster number @vcn in the runlist described by the ntfs
  * inode @ni and return the address of the runlist element containing the @vcn.
@@ -246,9 +418,22 @@ retry_remap:
  * If the @vcn is not mapped yet, the attempt is made to map the attribute
  * extent containing the @vcn and the vcn to lcn conversion is retried.
  *
- * If @write_locked is true the caller has locked the runlist for writing and
- * if false for reading.
- *
+ * If @ctx is specified, it is an active search context of @ni and its base mft
+ * record.  This is needed when ntfs_attr_find_vcn_nolock() encounters unmapped
+ * runlist fragments and allows their mapping.  If you do not have the mft
+ * record mapped, you can specify @ctx as NULL and ntfs_attr_find_vcn_nolock()
+ * will perform the necessary mapping and unmapping.
+ *
+ * Note, ntfs_attr_find_vcn_nolock() saves the state of @ctx on entry and
+ * restores it before returning.  Thus, @ctx will be left pointing to the same
+ * attribute on return as on entry.  However, the actual pointers in @ctx may
+ * point to different memory locations on return, so you must remember to reset
+ * any cached pointers from the @ctx, i.e. after the call to
+ * ntfs_attr_find_vcn_nolock(), you will probably want to do:
+ *     m = ctx->mrec;
+ *     a = ctx->attr;
+ * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
+ * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
  * Note you need to distinguish between the lcn of the returned runlist element
  * being >= 0 and LCN_HOLE.  In the later case you have to return zeroes on
  * read and allocate clusters on write.
@@ -263,22 +448,31 @@ retry_remap:
  *     -ENOMEM - Not enough memory to map runlist.
  *     -EIO    - Critical error (runlist/file is corrupt, i/o error, etc).
  *
- * Locking: - The runlist must be locked on entry and is left locked on return.
- *         - If @write_locked is FALSE, i.e. the runlist is locked for reading,
- *           the lock may be dropped inside the function so you cannot rely on
- *           the runlist still being the same when this function returns.
+ * WARNING: If @ctx is supplied, regardless of whether success or failure is
+ *         returned, you need to check IS_ERR(@ctx->mrec) and if TRUE the @ctx
+ *         is no longer valid, i.e. you need to either call
+ *         ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
+ *         In that case PTR_ERR(@ctx->mrec) will give you the error code for
+ *         why the mapping of the old inode failed.
+ *
+ * Locking: - The runlist described by @ni must be locked for writing on entry
+ *           and is locked on return.  Note the runlist may be modified when
+ *           needed runlist fragments need to be mapped.
+ *         - If @ctx is NULL, the base mft record of @ni must not be mapped on
+ *           entry and it will be left unmapped on return.
+ *         - If @ctx is not NULL, the base mft record must be mapped on entry
+ *           and it will be left mapped on return.
  */
 runlist_element *ntfs_attr_find_vcn_nolock(ntfs_inode *ni, const VCN vcn,
-               const BOOL write_locked)
+               ntfs_attr_search_ctx *ctx)
 {
        unsigned long flags;
        runlist_element *rl;
        int err = 0;
        BOOL is_retry = FALSE;
 
-       ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, %s_locked.",
-                       ni->mft_no, (unsigned long long)vcn,
-                       write_locked ? "write" : "read");
+       ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, with%s ctx.",
+                       ni->mft_no, (unsigned long long)vcn, ctx ? "" : "out");
        BUG_ON(!ni);
        BUG_ON(!NInoNonResident(ni));
        BUG_ON(vcn < 0);
@@ -312,33 +506,22 @@ retry_remap:
        }
        if (!err && !is_retry) {
                /*
-                * The @vcn is in an unmapped region, map the runlist and
-                * retry.
+                * If the search context is invalid we cannot map the unmapped
+                * region.
                 */
-               if (!write_locked) {
-                       up_read(&ni->runlist.lock);
-                       down_write(&ni->runlist.lock);
-                       if (unlikely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) !=
-                                       LCN_RL_NOT_MAPPED)) {
-                               up_write(&ni->runlist.lock);
-                               down_read(&ni->runlist.lock);
+               if (IS_ERR(ctx->mrec))
+                       err = PTR_ERR(ctx->mrec);
+               else {
+                       /*
+                        * The @vcn is in an unmapped region, map the runlist
+                        * and retry.
+                        */
+                       err = ntfs_map_runlist_nolock(ni, vcn, ctx);
+                       if (likely(!err)) {
+                               is_retry = TRUE;
                                goto retry_remap;
                        }
                }
-               err = ntfs_map_runlist_nolock(ni, vcn);
-               if (!write_locked) {
-                       up_write(&ni->runlist.lock);
-                       down_read(&ni->runlist.lock);
-               }
-               if (likely(!err)) {
-                       is_retry = TRUE;
-                       goto retry_remap;
-               }
-               /*
-                * -EINVAL coming from a failed mapping attempt is equivalent
-                * to i/o error for us as it should not happen in our code
-                * paths.
-                */
                if (err == -EINVAL)
                        err = -EIO;
        } else if (!err)
@@ -1011,6 +1194,7 @@ int ntfs_attr_lookup(const ATTR_TYPE type, const ntfschar *name,
        ntfs_inode *base_ni;
 
        ntfs_debug("Entering.");
+       BUG_ON(IS_ERR(ctx->mrec));
        if (ctx->base_ntfs_ino)
                base_ni = ctx->base_ntfs_ino;
        else
@@ -1319,10 +1503,17 @@ int ntfs_resident_attr_value_resize(MFT_RECORD *m, ATTR_RECORD *a,
 /**
  * ntfs_attr_make_non_resident - convert a resident to a non-resident attribute
  * @ni:                ntfs inode describing the attribute to convert
+ * @data_size: size of the resident data to copy to the non-resident attribute
  *
  * Convert the resident ntfs attribute described by the ntfs inode @ni to a
  * non-resident one.
  *
+ * @data_size must be equal to the attribute value size.  This is needed since
+ * we need to know the size before we can map the mft record and our callers
+ * always know it.  The reason we cannot simply read the size from the vfs
+ * inode i_size is that this is not necessarily uptodate.  This happens when
+ * ntfs_attr_make_non_resident() is called in the ->truncate call path(s).
+ *
  * Return 0 on success and -errno on error.  The following error return codes
  * are defined:
  *     -EPERM  - The attribute is not allowed to be non-resident.
@@ -1343,7 +1534,7 @@ int ntfs_resident_attr_value_resize(MFT_RECORD *m, ATTR_RECORD *a,
  *
  * Locking: - The caller must hold i_sem on the inode.
  */
-int ntfs_attr_make_non_resident(ntfs_inode *ni)
+int ntfs_attr_make_non_resident(ntfs_inode *ni, const u32 data_size)
 {
        s64 new_size;
        struct inode *vi = VFS_I(ni);
@@ -1381,11 +1572,9 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
         * The size needs to be aligned to a cluster boundary for allocation
         * purposes.
         */
-       new_size = (i_size_read(vi) + vol->cluster_size - 1) &
+       new_size = (data_size + vol->cluster_size - 1) &
                        ~(vol->cluster_size - 1);
        if (new_size > 0) {
-               runlist_element *rl2;
-
                /*
                 * Will need the page later and since the page lock nests
                 * outside all ntfs locks, we need to get the page now.
@@ -1396,7 +1585,7 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
                        return -ENOMEM;
                /* Start by allocating clusters to hold the attribute value. */
                rl = ntfs_cluster_alloc(vol, 0, new_size >>
-                               vol->cluster_size_bits, -1, DATA_ZONE);
+                               vol->cluster_size_bits, -1, DATA_ZONE, TRUE);
                if (IS_ERR(rl)) {
                        err = PTR_ERR(rl);
                        ntfs_debug("Failed to allocate cluster%s, error code "
@@ -1405,12 +1594,6 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
                                        err);
                        goto page_err_out;
                }
-               /* Change the runlist terminator to LCN_ENOENT. */
-               rl2 = rl;
-               while (rl2->length)
-                       rl2++;
-               BUG_ON(rl2->lcn != LCN_RL_NOT_MAPPED);
-               rl2->lcn = LCN_ENOENT;
        } else {
                rl = NULL;
                page = NULL;
@@ -1473,7 +1656,7 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
         * attribute value.
         */
        attr_size = le32_to_cpu(a->data.resident.value_length);
-       BUG_ON(attr_size != i_size_read(vi));
+       BUG_ON(attr_size != data_size);
        if (page && !PageUptodate(page)) {
                kaddr = kmap_atomic(page, KM_USER0);
                memcpy(kaddr, (u8*)a +
@@ -1538,7 +1721,9 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
                                ffs(ni->itype.compressed.block_size) - 1;
                ni->itype.compressed.block_clusters = 1U <<
                                a->data.non_resident.compression_unit;
-       }
+               vi->i_blocks = ni->itype.compressed.size >> 9;
+       } else
+               vi->i_blocks = ni->allocated_size >> 9;
        write_unlock_irqrestore(&ni->size_lock, flags);
        /*
         * This needs to be last since the address space operations ->readpage
@@ -1651,6 +1836,640 @@ page_err_out:
        return err;
 }
 
+/**
+ * ntfs_attr_extend_allocation - extend the allocated space of an attribute
+ * @ni:                        ntfs inode of the attribute whose allocation to extend
+ * @new_alloc_size:    new size in bytes to which to extend the allocation to
+ * @new_data_size:     new size in bytes to which to extend the data to
+ * @data_start:                beginning of region which is required to be non-sparse
+ *
+ * Extend the allocated space of an attribute described by the ntfs inode @ni
+ * to @new_alloc_size bytes.  If @data_start is -1, the whole extension may be
+ * implemented as a hole in the file (as long as both the volume and the ntfs
+ * inode @ni have sparse support enabled).  If @data_start is >= 0, then the
+ * region between the old allocated size and @data_start - 1 may be made sparse
+ * but the regions between @data_start and @new_alloc_size must be backed by
+ * actual clusters.
+ *
+ * If @new_data_size is -1, it is ignored.  If it is >= 0, then the data size
+ * of the attribute is extended to @new_data_size.  Note that the i_size of the
+ * vfs inode is not updated.  Only the data size in the base attribute record
+ * is updated.  The caller has to update i_size separately if this is required.
+ * WARNING: It is a BUG() for @new_data_size to be smaller than the old data
+ * size as well as for @new_data_size to be greater than @new_alloc_size.
+ *
+ * For resident attributes this involves resizing the attribute record and if
+ * necessary moving it and/or other attributes into extent mft records and/or
+ * converting the attribute to a non-resident attribute which in turn involves
+ * extending the allocation of a non-resident attribute as described below.
+ *
+ * For non-resident attributes this involves allocating clusters in the data
+ * zone on the volume (except for regions that are being made sparse) and
+ * extending the run list to describe the allocated clusters as well as
+ * updating the mapping pairs array of the attribute.  This in turn involves
+ * resizing the attribute record and if necessary moving it and/or other
+ * attributes into extent mft records and/or splitting the attribute record
+ * into multiple extent attribute records.
+ *
+ * Also, the attribute list attribute is updated if present and in some of the
+ * above cases (the ones where extent mft records/attributes come into play),
+ * an attribute list attribute is created if not already present.
+ *
+ * Return the new allocated size on success and -errno on error.  In the case
+ * that an error is encountered but a partial extension at least up to
+ * @data_start (if present) is possible, the allocation is partially extended
+ * and this is returned.  This means the caller must check the returned size to
+ * determine if the extension was partial.  If @data_start is -1 then partial
+ * allocations are not performed.
+ *
+ * WARNING: Do not call ntfs_attr_extend_allocation() for $MFT/$DATA.
+ *
+ * Locking: This function takes the runlist lock of @ni for writing as well as
+ * locking the mft record of the base ntfs inode.  These locks are maintained
+ * throughout execution of the function.  These locks are required so that the
+ * attribute can be resized safely and so that it can for example be converted
+ * from resident to non-resident safely.
+ *
+ * TODO: At present attribute list attribute handling is not implemented.
+ *
+ * TODO: At present it is not safe to call this function for anything other
+ * than the $DATA attribute(s) of an uncompressed and unencrypted file.
+ */
+s64 ntfs_attr_extend_allocation(ntfs_inode *ni, s64 new_alloc_size,
+               const s64 new_data_size, const s64 data_start)
+{
+       VCN vcn;
+       s64 ll, allocated_size, start = data_start;
+       struct inode *vi = VFS_I(ni);
+       ntfs_volume *vol = ni->vol;
+       ntfs_inode *base_ni;
+       MFT_RECORD *m;
+       ATTR_RECORD *a;
+       ntfs_attr_search_ctx *ctx;
+       runlist_element *rl, *rl2;
+       unsigned long flags;
+       int err, mp_size;
+       u32 attr_len = 0; /* Silence stupid gcc warning. */
+       BOOL mp_rebuilt;
+
+#ifdef NTFS_DEBUG
+       read_lock_irqsave(&ni->size_lock, flags);
+       allocated_size = ni->allocated_size;
+       read_unlock_irqrestore(&ni->size_lock, flags);
+       ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, "
+                       "old_allocated_size 0x%llx, "
+                       "new_allocated_size 0x%llx, new_data_size 0x%llx, "
+                       "data_start 0x%llx.", vi->i_ino,
+                       (unsigned)le32_to_cpu(ni->type),
+                       (unsigned long long)allocated_size,
+                       (unsigned long long)new_alloc_size,
+                       (unsigned long long)new_data_size,
+                       (unsigned long long)start);
+#endif
+retry_extend:
+       /*
+        * For non-resident attributes, @start and @new_size need to be aligned
+        * to cluster boundaries for allocation purposes.
+        */
+       if (NInoNonResident(ni)) {
+               if (start > 0)
+                       start &= ~(s64)vol->cluster_size_mask;
+               new_alloc_size = (new_alloc_size + vol->cluster_size - 1) &
+                               ~(s64)vol->cluster_size_mask;
+       }
+       BUG_ON(new_data_size >= 0 && new_data_size > new_alloc_size);
+       /* Check if new size is allowed in $AttrDef. */
+       err = ntfs_attr_size_bounds_check(vol, ni->type, new_alloc_size);
+       if (unlikely(err)) {
+               /* Only emit errors when the write will fail completely. */
+               read_lock_irqsave(&ni->size_lock, flags);
+               allocated_size = ni->allocated_size;
+               read_unlock_irqrestore(&ni->size_lock, flags);
+               if (start < 0 || start >= allocated_size) {
+                       if (err == -ERANGE) {
+                               ntfs_error(vol->sb, "Cannot extend allocation "
+                                               "of inode 0x%lx, attribute "
+                                               "type 0x%x, because the new "
+                                               "allocation would exceed the "
+                                               "maximum allowed size for "
+                                               "this attribute type.",
+                                               vi->i_ino, (unsigned)
+                                               le32_to_cpu(ni->type));
+                       } else {
+                               ntfs_error(vol->sb, "Cannot extend allocation "
+                                               "of inode 0x%lx, attribute "
+                                               "type 0x%x, because this "
+                                               "attribute type is not "
+                                               "defined on the NTFS volume.  "
+                                               "Possible corruption!  You "
+                                               "should run chkdsk!",
+                                               vi->i_ino, (unsigned)
+                                               le32_to_cpu(ni->type));
+                       }
+               }
+               /* Translate error code to be POSIX conformant for write(2). */
+               if (err == -ERANGE)
+                       err = -EFBIG;
+               else
+                       err = -EIO;
+               return err;
+       }
+       if (!NInoAttr(ni))
+               base_ni = ni;
+       else
+               base_ni = ni->ext.base_ntfs_ino;
+       /*
+        * We will be modifying both the runlist (if non-resident) and the mft
+        * record so lock them both down.
+        */
+       down_write(&ni->runlist.lock);
+       m = map_mft_record(base_ni);
+       if (IS_ERR(m)) {
+               err = PTR_ERR(m);
+               m = NULL;
+               ctx = NULL;
+               goto err_out;
+       }
+       ctx = ntfs_attr_get_search_ctx(base_ni, m);
+       if (unlikely(!ctx)) {
+               err = -ENOMEM;
+               goto err_out;
+       }
+       read_lock_irqsave(&ni->size_lock, flags);
+       allocated_size = ni->allocated_size;
+       read_unlock_irqrestore(&ni->size_lock, flags);
+       /*
+        * If non-resident, seek to the last extent.  If resident, there is
+        * only one extent, so seek to that.
+        */
+       vcn = NInoNonResident(ni) ? allocated_size >> vol->cluster_size_bits :
+                       0;
+       /*
+        * Abort if someone did the work whilst we waited for the locks.  If we
+        * just converted the attribute from resident to non-resident it is
+        * likely that exactly this has happened already.  We cannot quite
+        * abort if we need to update the data size.
+        */
+       if (unlikely(new_alloc_size <= allocated_size)) {
+               ntfs_debug("Allocated size already exceeds requested size.");
+               new_alloc_size = allocated_size;
+               if (new_data_size < 0)
+                       goto done;
+               /*
+                * We want the first attribute extent so that we can update the
+                * data size.
+                */
+               vcn = 0;
+       }
+       err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+                       CASE_SENSITIVE, vcn, NULL, 0, ctx);
+       if (unlikely(err)) {
+               if (err == -ENOENT)
+                       err = -EIO;
+               goto err_out;
+       }
+       m = ctx->mrec;
+       a = ctx->attr;
+       /* Use goto to reduce indentation. */
+       if (a->non_resident)
+               goto do_non_resident_extend;
+       BUG_ON(NInoNonResident(ni));
+       /* The total length of the attribute value. */
+       attr_len = le32_to_cpu(a->data.resident.value_length);
+       /*
+        * Extend the attribute record to be able to store the new attribute
+        * size.  ntfs_attr_record_resize() will not do anything if the size is
+        * not changing.
+        */
+       if (new_alloc_size < vol->mft_record_size &&
+                       !ntfs_attr_record_resize(m, a,
+                       le16_to_cpu(a->data.resident.value_offset) +
+                       new_alloc_size)) {
+               /* The resize succeeded! */
+               write_lock_irqsave(&ni->size_lock, flags);
+               ni->allocated_size = le32_to_cpu(a->length) -
+                               le16_to_cpu(a->data.resident.value_offset);
+               write_unlock_irqrestore(&ni->size_lock, flags);
+               if (new_data_size >= 0) {
+                       BUG_ON(new_data_size < attr_len);
+                       a->data.resident.value_length =
+                                       cpu_to_le32((u32)new_data_size);
+               }
+               goto flush_done;
+       }
+       /*
+        * We have to drop all the locks so we can call
+        * ntfs_attr_make_non_resident().  This could be optimised by try-
+        * locking the first page cache page and only if that fails dropping
+        * the locks, locking the page, and redoing all the locking and
+        * lookups.  While this would be a huge optimisation, it is not worth
+        * it as this is definitely a slow code path.
+        */
+       ntfs_attr_put_search_ctx(ctx);
+       unmap_mft_record(base_ni);
+       up_write(&ni->runlist.lock);
+       /*
+        * Not enough space in the mft record, try to make the attribute
+        * non-resident and if successful restart the extension process.
+        */
+       err = ntfs_attr_make_non_resident(ni, attr_len);
+       if (likely(!err))
+               goto retry_extend;
+       /*
+        * Could not make non-resident.  If this is due to this not being
+        * permitted for this attribute type or there not being enough space,
+        * try to make other attributes non-resident.  Otherwise fail.
+        */
+       if (unlikely(err != -EPERM && err != -ENOSPC)) {
+               /* Only emit errors when the write will fail completely. */
+               read_lock_irqsave(&ni->size_lock, flags);
+               allocated_size = ni->allocated_size;
+               read_unlock_irqrestore(&ni->size_lock, flags);
+               if (start < 0 || start >= allocated_size)
+                       ntfs_error(vol->sb, "Cannot extend allocation of "
+                                       "inode 0x%lx, attribute type 0x%x, "
+                                       "because the conversion from resident "
+                                       "to non-resident attribute failed "
+                                       "with error code %i.", vi->i_ino,
+                                       (unsigned)le32_to_cpu(ni->type), err);
+               if (err != -ENOMEM)
+                       err = -EIO;
+               goto conv_err_out;
+       }
+       /* TODO: Not implemented from here, abort. */
+       read_lock_irqsave(&ni->size_lock, flags);
+       allocated_size = ni->allocated_size;
+       read_unlock_irqrestore(&ni->size_lock, flags);
+       if (start < 0 || start >= allocated_size) {
+               if (err == -ENOSPC)
+                       ntfs_error(vol->sb, "Not enough space in the mft "
+                                       "record/on disk for the non-resident "
+                                       "attribute value.  This case is not "
+                                       "implemented yet.");
+               else /* if (err == -EPERM) */
+                       ntfs_error(vol->sb, "This attribute type may not be "
+                                       "non-resident.  This case is not "
+                                       "implemented yet.");
+       }
+       err = -EOPNOTSUPP;
+       goto conv_err_out;
+#if 0
+       // TODO: Attempt to make other attributes non-resident.
+       if (!err)
+               goto do_resident_extend;
+       /*
+        * Both the attribute list attribute and the standard information
+        * attribute must remain in the base inode.  Thus, if this is one of
+        * these attributes, we have to try to move other attributes out into
+        * extent mft records instead.
+        */
+       if (ni->type == AT_ATTRIBUTE_LIST ||
+                       ni->type == AT_STANDARD_INFORMATION) {
+               // TODO: Attempt to move other attributes into extent mft
+               // records.
+               err = -EOPNOTSUPP;
+               if (!err)
+                       goto do_resident_extend;
+               goto err_out;
+       }
+       // TODO: Attempt to move this attribute to an extent mft record, but
+       // only if it is not already the only attribute in an mft record in
+       // which case there would be nothing to gain.
+       err = -EOPNOTSUPP;
+       if (!err)
+               goto do_resident_extend;
+       /* There is nothing we can do to make enough space. )-: */
+       goto err_out;
+#endif
+do_non_resident_extend:
+       BUG_ON(!NInoNonResident(ni));
+       if (new_alloc_size == allocated_size) {
+               BUG_ON(vcn);
+               goto alloc_done;
+       }
+       /*
+        * If the data starts after the end of the old allocation, this is a
+        * $DATA attribute and sparse attributes are enabled on the volume and
+        * for this inode, then create a sparse region between the old
+        * allocated size and the start of the data.  Otherwise simply proceed
+        * with filling the whole space between the old allocated size and the
+        * new allocated size with clusters.
+        */
+       if ((start >= 0 && start <= allocated_size) || ni->type != AT_DATA ||
+                       !NVolSparseEnabled(vol) || NInoSparseDisabled(ni))
+               goto skip_sparse;
+       // TODO: This is not implemented yet.  We just fill in with real
+       // clusters for now...
+       ntfs_debug("Inserting holes is not-implemented yet.  Falling back to "
+                       "allocating real clusters instead.");
+skip_sparse:
+       rl = ni->runlist.rl;
+       if (likely(rl)) {
+               /* Seek to the end of the runlist. */
+               while (rl->length)
+                       rl++;
+       }
+       /* If this attribute extent is not mapped, map it now. */
+       if (unlikely(!rl || rl->lcn == LCN_RL_NOT_MAPPED ||
+                       (rl->lcn == LCN_ENOENT && rl > ni->runlist.rl &&
+                       (rl-1)->lcn == LCN_RL_NOT_MAPPED))) {
+               if (!rl && !allocated_size)
+                       goto first_alloc;
+               rl = ntfs_mapping_pairs_decompress(vol, a, ni->runlist.rl);
+               if (IS_ERR(rl)) {
+                       err = PTR_ERR(rl);
+                       if (start < 0 || start >= allocated_size)
+                               ntfs_error(vol->sb, "Cannot extend allocation "
+                                               "of inode 0x%lx, attribute "
+                                               "type 0x%x, because the "
+                                               "mapping of a runlist "
+                                               "fragment failed with error "
+                                               "code %i.", vi->i_ino,
+                                               (unsigned)le32_to_cpu(ni->type),
+                                               err);
+                       if (err != -ENOMEM)
+                               err = -EIO;
+                       goto err_out;
+               }
+               ni->runlist.rl = rl;
+               /* Seek to the end of the runlist. */
+               while (rl->length)
+                       rl++;
+       }
+       /*
+        * We now know the runlist of the last extent is mapped and @rl is at
+        * the end of the runlist.  We want to begin allocating clusters
+        * starting at the last allocated cluster to reduce fragmentation.  If
+        * there are no valid LCNs in the attribute we let the cluster
+        * allocator choose the starting cluster.
+        */
+       /* If the last LCN is a hole or simillar seek back to last real LCN. */
+       while (rl->lcn < 0 && rl > ni->runlist.rl)
+               rl--;
+first_alloc:
+       // FIXME: Need to implement partial allocations so at least part of the
+       // write can be performed when start >= 0.  (Needed for POSIX write(2)
+       // conformance.)
+       rl2 = ntfs_cluster_alloc(vol, allocated_size >> vol->cluster_size_bits,
+                       (new_alloc_size - allocated_size) >>
+                       vol->cluster_size_bits, (rl && (rl->lcn >= 0)) ?
+                       rl->lcn + rl->length : -1, DATA_ZONE, TRUE);
+       if (IS_ERR(rl2)) {
+               err = PTR_ERR(rl2);
+               if (start < 0 || start >= allocated_size)
+                       ntfs_error(vol->sb, "Cannot extend allocation of "
+                                       "inode 0x%lx, attribute type 0x%x, "
+                                       "because the allocation of clusters "
+                                       "failed with error code %i.", vi->i_ino,
+                                       (unsigned)le32_to_cpu(ni->type), err);
+               if (err != -ENOMEM && err != -ENOSPC)
+                       err = -EIO;
+               goto err_out;
+       }
+       rl = ntfs_runlists_merge(ni->runlist.rl, rl2);
+       if (IS_ERR(rl)) {
+               err = PTR_ERR(rl);
+               if (start < 0 || start >= allocated_size)
+                       ntfs_error(vol->sb, "Cannot extend allocation of "
+                                       "inode 0x%lx, attribute type 0x%x, "
+                                       "because the runlist merge failed "
+                                       "with error code %i.", vi->i_ino,
+                                       (unsigned)le32_to_cpu(ni->type), err);
+               if (err != -ENOMEM)
+                       err = -EIO;
+               if (ntfs_cluster_free_from_rl(vol, rl2)) {
+                       ntfs_error(vol->sb, "Failed to release allocated "
+                                       "cluster(s) in error code path.  Run "
+                                       "chkdsk to recover the lost "
+                                       "cluster(s).");
+                       NVolSetErrors(vol);
+               }
+               ntfs_free(rl2);
+               goto err_out;
+       }
+       ni->runlist.rl = rl;
+       ntfs_debug("Allocated 0x%llx clusters.", (long long)(new_alloc_size -
+                       allocated_size) >> vol->cluster_size_bits);
+       /* Find the runlist element with which the attribute extent starts. */
+       ll = sle64_to_cpu(a->data.non_resident.lowest_vcn);
+       rl2 = ntfs_rl_find_vcn_nolock(rl, ll);
+       BUG_ON(!rl2);
+       BUG_ON(!rl2->length);
+       BUG_ON(rl2->lcn < LCN_HOLE);
+       mp_rebuilt = FALSE;
+       /* Get the size for the new mapping pairs array for this extent. */
+       mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, -1);
+       if (unlikely(mp_size <= 0)) {
+               err = mp_size;
+               if (start < 0 || start >= allocated_size)
+                       ntfs_error(vol->sb, "Cannot extend allocation of "
+                                       "inode 0x%lx, attribute type 0x%x, "
+                                       "because determining the size for the "
+                                       "mapping pairs failed with error code "
+                                       "%i.", vi->i_ino,
+                                       (unsigned)le32_to_cpu(ni->type), err);
+               err = -EIO;
+               goto undo_alloc;
+       }
+       /* Extend the attribute record to fit the bigger mapping pairs array. */
+       attr_len = le32_to_cpu(a->length);
+       err = ntfs_attr_record_resize(m, a, mp_size +
+                       le16_to_cpu(a->data.non_resident.mapping_pairs_offset));
+       if (unlikely(err)) {
+               BUG_ON(err != -ENOSPC);
+               // TODO: Deal with this by moving this extent to a new mft
+               // record or by starting a new extent in a new mft record,
+               // possibly by extending this extent partially and filling it
+               // and creating a new extent for the remainder, or by making
+               // other attributes non-resident and/or by moving other
+               // attributes out of this mft record.
+               if (start < 0 || start >= allocated_size)
+                       ntfs_error(vol->sb, "Not enough space in the mft "
+                                       "record for the extended attribute "
+                                       "record.  This case is not "
+                                       "implemented yet.");
+               err = -EOPNOTSUPP;
+               goto undo_alloc;
+       }
+       mp_rebuilt = TRUE;
+       /* Generate the mapping pairs array directly into the attr record. */
+       err = ntfs_mapping_pairs_build(vol, (u8*)a +
+                       le16_to_cpu(a->data.non_resident.mapping_pairs_offset),
+                       mp_size, rl2, ll, -1, NULL);
+       if (unlikely(err)) {
+               if (start < 0 || start >= allocated_size)
+                       ntfs_error(vol->sb, "Cannot extend allocation of "
+                                       "inode 0x%lx, attribute type 0x%x, "
+                                       "because building the mapping pairs "
+                                       "failed with error code %i.", vi->i_ino,
+                                       (unsigned)le32_to_cpu(ni->type), err);
+               err = -EIO;
+               goto undo_alloc;
+       }
+       /* Update the highest_vcn. */
+       a->data.non_resident.highest_vcn = cpu_to_sle64((new_alloc_size >>
+                       vol->cluster_size_bits) - 1);
+       /*
+        * We now have extended the allocated size of the attribute.  Reflect
+        * this in the ntfs_inode structure and the attribute record.
+        */
+       if (a->data.non_resident.lowest_vcn) {
+               /*
+                * We are not in the first attribute extent, switch to it, but
+                * first ensure the changes will make it to disk later.
+                */
+               flush_dcache_mft_record_page(ctx->ntfs_ino);
+               mark_mft_record_dirty(ctx->ntfs_ino);
+               ntfs_attr_reinit_search_ctx(ctx);
+               err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+                               CASE_SENSITIVE, 0, NULL, 0, ctx);
+               if (unlikely(err))
+                       goto restore_undo_alloc;
+               /* @m is not used any more so no need to set it. */
+               a = ctx->attr;
+       }
+       write_lock_irqsave(&ni->size_lock, flags);
+       ni->allocated_size = new_alloc_size;
+       a->data.non_resident.allocated_size = cpu_to_sle64(new_alloc_size);
+       /*
+        * FIXME: This would fail if @ni is a directory, $MFT, or an index,
+        * since those can have sparse/compressed set.  For example can be
+        * set compressed even though it is not compressed itself and in that
+        * case the bit means that files are to be created compressed in the
+        * directory...  At present this is ok as this code is only called for
+        * regular files, and only for their $DATA attribute(s).
+        * FIXME: The calculation is wrong if we created a hole above.  For now
+        * it does not matter as we never create holes.
+        */
+       if (NInoSparse(ni) || NInoCompressed(ni)) {
+               ni->itype.compressed.size += new_alloc_size - allocated_size;
+               a->data.non_resident.compressed_size =
+                               cpu_to_sle64(ni->itype.compressed.size);
+               vi->i_blocks = ni->itype.compressed.size >> 9;
+       } else
+               vi->i_blocks = new_alloc_size >> 9;
+       write_unlock_irqrestore(&ni->size_lock, flags);
+alloc_done:
+       if (new_data_size >= 0) {
+               BUG_ON(new_data_size <
+                               sle64_to_cpu(a->data.non_resident.data_size));
+               a->data.non_resident.data_size = cpu_to_sle64(new_data_size);
+       }
+flush_done:
+       /* Ensure the changes make it to disk. */
+       flush_dcache_mft_record_page(ctx->ntfs_ino);
+       mark_mft_record_dirty(ctx->ntfs_ino);
+done:
+       ntfs_attr_put_search_ctx(ctx);
+       unmap_mft_record(base_ni);
+       up_write(&ni->runlist.lock);
+       ntfs_debug("Done, new_allocated_size 0x%llx.",
+                       (unsigned long long)new_alloc_size);
+       return new_alloc_size;
+restore_undo_alloc:
+       if (start < 0 || start >= allocated_size)
+               ntfs_error(vol->sb, "Cannot complete extension of allocation "
+                               "of inode 0x%lx, attribute type 0x%x, because "
+                               "lookup of first attribute extent failed with "
+                               "error code %i.", vi->i_ino,
+                               (unsigned)le32_to_cpu(ni->type), err);
+       if (err == -ENOENT)
+               err = -EIO;
+       ntfs_attr_reinit_search_ctx(ctx);
+       if (ntfs_attr_lookup(ni->type, ni->name, ni->name_len, CASE_SENSITIVE,
+                       allocated_size >> vol->cluster_size_bits, NULL, 0,
+                       ctx)) {
+               ntfs_error(vol->sb, "Failed to find last attribute extent of "
+                               "attribute in error code path.  Run chkdsk to "
+                               "recover.");
+               write_lock_irqsave(&ni->size_lock, flags);
+               ni->allocated_size = new_alloc_size;
+               /*
+                * FIXME: This would fail if @ni is a directory...  See above.
+                * FIXME: The calculation is wrong if we created a hole above.
+                * For now it does not matter as we never create holes.
+                */
+               if (NInoSparse(ni) || NInoCompressed(ni)) {
+                       ni->itype.compressed.size += new_alloc_size -
+                                       allocated_size;
+                       vi->i_blocks = ni->itype.compressed.size >> 9;
+               } else
+                       vi->i_blocks = new_alloc_size >> 9;
+               write_unlock_irqrestore(&ni->size_lock, flags);
+               ntfs_attr_put_search_ctx(ctx);
+               unmap_mft_record(base_ni);
+               up_write(&ni->runlist.lock);
+               /*
+                * The only thing that is now wrong is the allocated size of the
+                * base attribute extent which chkdsk should be able to fix.
+                */
+               NVolSetErrors(vol);
+               return err;
+       }
+       ctx->attr->data.non_resident.highest_vcn = cpu_to_sle64(
+                       (allocated_size >> vol->cluster_size_bits) - 1);
+undo_alloc:
+       ll = allocated_size >> vol->cluster_size_bits;
+       if (ntfs_cluster_free(ni, ll, -1, ctx) < 0) {
+               ntfs_error(vol->sb, "Failed to release allocated cluster(s) "
+                               "in error code path.  Run chkdsk to recover "
+                               "the lost cluster(s).");
+               NVolSetErrors(vol);
+       }
+       m = ctx->mrec;
+       a = ctx->attr;
+       /*
+        * If the runlist truncation fails and/or the search context is no
+        * longer valid, we cannot resize the attribute record or build the
+        * mapping pairs array thus we mark the inode bad so that no access to
+        * the freed clusters can happen.
+        */
+       if (ntfs_rl_truncate_nolock(vol, &ni->runlist, ll) || IS_ERR(m)) {
+               ntfs_error(vol->sb, "Failed to %s in error code path.  Run "
+                               "chkdsk to recover.", IS_ERR(m) ?
+                               "restore attribute search context" :
+                               "truncate attribute runlist");
+               make_bad_inode(vi);
+               make_bad_inode(VFS_I(base_ni));
+               NVolSetErrors(vol);
+       } else if (mp_rebuilt) {
+               if (ntfs_attr_record_resize(m, a, attr_len)) {
+                       ntfs_error(vol->sb, "Failed to restore attribute "
+                                       "record in error code path.  Run "
+                                       "chkdsk to recover.");
+                       make_bad_inode(vi);
+                       make_bad_inode(VFS_I(base_ni));
+                       NVolSetErrors(vol);
+               } else /* if (success) */ {
+                       if (ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
+                                       a->data.non_resident.
+                                       mapping_pairs_offset), attr_len -
+                                       le16_to_cpu(a->data.non_resident.
+                                       mapping_pairs_offset), rl2, ll, -1,
+                                       NULL)) {
+                               ntfs_error(vol->sb, "Failed to restore "
+                                               "mapping pairs array in error "
+                                               "code path.  Run chkdsk to "
+                                               "recover.");
+                               make_bad_inode(vi);
+                               make_bad_inode(VFS_I(base_ni));
+                               NVolSetErrors(vol);
+                       }
+                       flush_dcache_mft_record_page(ctx->ntfs_ino);
+                       mark_mft_record_dirty(ctx->ntfs_ino);
+               }
+       }
+err_out:
+       if (ctx)
+               ntfs_attr_put_search_ctx(ctx);
+       if (m)
+               unmap_mft_record(base_ni);
+       up_write(&ni->runlist.lock);
+conv_err_out:
+       ntfs_debug("Failed.  Returning error code %i.", err);
+       return err;
+}
+
 /**
  * ntfs_attr_set - fill (a part of) an attribute with a byte
  * @ni:                ntfs inode describing the attribute to fill
@@ -1773,6 +2592,8 @@ int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val)
                /* Finally unlock and release the page. */
                unlock_page(page);
                page_cache_release(page);
+               balance_dirty_pages_ratelimited(mapping);
+               cond_resched();
        }
        /* If there is a last partial page, need to do it the slow way. */
        if (end_ofs) {
index 0618ed6fd7b35de101192db0a058baffd99158cf..9074886b44ba194d1c6cffed6f8bb838f2263f97 100644 (file)
@@ -60,14 +60,15 @@ typedef struct {
        ATTR_RECORD *base_attr;
 } ntfs_attr_search_ctx;
 
-extern int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn);
+extern int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn,
+               ntfs_attr_search_ctx *ctx);
 extern int ntfs_map_runlist(ntfs_inode *ni, VCN vcn);
 
 extern LCN ntfs_attr_vcn_to_lcn_nolock(ntfs_inode *ni, const VCN vcn,
                const BOOL write_locked);
 
 extern runlist_element *ntfs_attr_find_vcn_nolock(ntfs_inode *ni,
-               const VCN vcn, const BOOL write_locked);
+               const VCN vcn, ntfs_attr_search_ctx *ctx);
 
 int ntfs_attr_lookup(const ATTR_TYPE type, const ntfschar *name,
                const u32 name_len, const IGNORE_CASE_BOOL ic,
@@ -102,7 +103,10 @@ extern int ntfs_attr_record_resize(MFT_RECORD *m, ATTR_RECORD *a, u32 new_size);
 extern int ntfs_resident_attr_value_resize(MFT_RECORD *m, ATTR_RECORD *a,
                const u32 new_size);
 
-extern int ntfs_attr_make_non_resident(ntfs_inode *ni);
+extern int ntfs_attr_make_non_resident(ntfs_inode *ni, const u32 data_size);
+
+extern s64 ntfs_attr_extend_allocation(ntfs_inode *ni, s64 new_alloc_size,
+               const s64 new_data_size, const s64 data_start);
 
 extern int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt,
                const u8 val);
index be9fd1dd423d18de8bab0c320f52af5d5ba48392..cf2a0e2330dfdca288f08cbba86b9bc87b83ab55 100644 (file)
  * Foundation,Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#include <linux/pagemap.h>
 #include <linux/buffer_head.h>
+#include <linux/pagemap.h>
+#include <linux/pagevec.h>
+#include <linux/sched.h>
+#include <linux/swap.h>
+#include <linux/uio.h>
+#include <linux/writeback.h>
 
+#include <asm/page.h>
+#include <asm/uaccess.h>
+
+#include "attrib.h"
+#include "bitmap.h"
 #include "inode.h"
 #include "debug.h"
+#include "lcnalloc.h"
+#include "malloc.h"
+#include "mft.h"
 #include "ntfs.h"
 
 /**
@@ -55,6 +68,2176 @@ static int ntfs_file_open(struct inode *vi, struct file *filp)
 
 #ifdef NTFS_RW
 
+/**
+ * ntfs_attr_extend_initialized - extend the initialized size of an attribute
+ * @ni:                        ntfs inode of the attribute to extend
+ * @new_init_size:     requested new initialized size in bytes
+ * @cached_page:       store any allocated but unused page here
+ * @lru_pvec:          lru-buffering pagevec of the caller
+ *
+ * Extend the initialized size of an attribute described by the ntfs inode @ni
+ * to @new_init_size bytes.  This involves zeroing any non-sparse space between
+ * the old initialized size and @new_init_size both in the page cache and on
+ * disk (if relevant complete pages are zeroed in the page cache then these may
+ * simply be marked dirty for later writeout).  There is one caveat and that is
+ * that if any uptodate page cache pages between the old initialized size and
+ * the smaller of @new_init_size and the file size (vfs inode->i_size) are in
+ * memory, these need to be marked dirty without being zeroed since they could
+ * be non-zero due to mmap() based writes.
+ *
+ * As a side-effect, the file size (vfs inode->i_size) may be incremented as,
+ * in the resident attribute case, it is tied to the initialized size and, in
+ * the non-resident attribute case, it may not fall below the initialized size.
+ *
+ * Note that if the attribute is resident, we do not need to touch the page
+ * cache at all.  This is because if the page cache page is not uptodate we
+ * bring it uptodate later, when doing the write to the mft record since we
+ * then already have the page mapped.  And if the page is uptodate, the
+ * non-initialized region will already have been zeroed when the page was
+ * brought uptodate and the region may in fact already have been overwritten
+ * with new data via mmap() based writes, so we cannot just zero it.  And since
+ * POSIX specifies that the behaviour of resizing a file whilst it is mmap()ped
+ * is unspecified, we choose not to do zeroing and thus we do not need to touch
+ * the page at all.  For a more detailed explanation see ntfs_truncate() which
+ * is in fs/ntfs/inode.c.
+ *
+ * @cached_page and @lru_pvec are just optimisations for dealing with multiple
+ * pages.
+ *
+ * Return 0 on success and -errno on error.  In the case that an error is
+ * encountered it is possible that the initialized size will already have been
+ * incremented some way towards @new_init_size but it is guaranteed that if
+ * this is the case, the necessary zeroing will also have happened and that all
+ * metadata is self-consistent.
+ *
+ * Locking: This function locks the mft record of the base ntfs inode and
+ * maintains the lock throughout execution of the function.  This is required
+ * so that the initialized size of the attribute can be modified safely.
+ */
+static int ntfs_attr_extend_initialized(ntfs_inode *ni, const s64 new_init_size,
+               struct page **cached_page, struct pagevec *lru_pvec)
+{
+       s64 old_init_size;
+       loff_t old_i_size;
+       pgoff_t index, end_index;
+       unsigned long flags;
+       struct inode *vi = VFS_I(ni);
+       ntfs_inode *base_ni;
+       MFT_RECORD *m = NULL;
+       ATTR_RECORD *a;
+       ntfs_attr_search_ctx *ctx = NULL;
+       struct address_space *mapping;
+       struct page *page = NULL;
+       u8 *kattr;
+       int err;
+       u32 attr_len;
+
+       read_lock_irqsave(&ni->size_lock, flags);
+       old_init_size = ni->initialized_size;
+       old_i_size = i_size_read(vi);
+       BUG_ON(new_init_size > ni->allocated_size);
+       read_unlock_irqrestore(&ni->size_lock, flags);
+       ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, "
+                       "old_initialized_size 0x%llx, "
+                       "new_initialized_size 0x%llx, i_size 0x%llx.",
+                       vi->i_ino, (unsigned)le32_to_cpu(ni->type),
+                       (unsigned long long)old_init_size,
+                       (unsigned long long)new_init_size, old_i_size);
+       if (!NInoAttr(ni))
+               base_ni = ni;
+       else
+               base_ni = ni->ext.base_ntfs_ino;
+       /* Use goto to reduce indentation and we need the label below anyway. */
+       if (NInoNonResident(ni))
+               goto do_non_resident_extend;
+       BUG_ON(old_init_size != old_i_size);
+       m = map_mft_record(base_ni);
+       if (IS_ERR(m)) {
+               err = PTR_ERR(m);
+               m = NULL;
+               goto err_out;
+       }
+       ctx = ntfs_attr_get_search_ctx(base_ni, m);
+       if (unlikely(!ctx)) {
+               err = -ENOMEM;
+               goto err_out;
+       }
+       err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+                       CASE_SENSITIVE, 0, NULL, 0, ctx);
+       if (unlikely(err)) {
+               if (err == -ENOENT)
+                       err = -EIO;
+               goto err_out;
+       }
+       m = ctx->mrec;
+       a = ctx->attr;
+       BUG_ON(a->non_resident);
+       /* The total length of the attribute value. */
+       attr_len = le32_to_cpu(a->data.resident.value_length);
+       BUG_ON(old_i_size != (loff_t)attr_len);
+       /*
+        * Do the zeroing in the mft record and update the attribute size in
+        * the mft record.
+        */
+       kattr = (u8*)a + le16_to_cpu(a->data.resident.value_offset);
+       memset(kattr + attr_len, 0, new_init_size - attr_len);
+       a->data.resident.value_length = cpu_to_le32((u32)new_init_size);
+       /* Finally, update the sizes in the vfs and ntfs inodes. */
+       write_lock_irqsave(&ni->size_lock, flags);
+       i_size_write(vi, new_init_size);
+       ni->initialized_size = new_init_size;
+       write_unlock_irqrestore(&ni->size_lock, flags);
+       goto done;
+do_non_resident_extend:
+       /*
+        * If the new initialized size @new_init_size exceeds the current file
+        * size (vfs inode->i_size), we need to extend the file size to the
+        * new initialized size.
+        */
+       if (new_init_size > old_i_size) {
+               m = map_mft_record(base_ni);
+               if (IS_ERR(m)) {
+                       err = PTR_ERR(m);
+                       m = NULL;
+                       goto err_out;
+               }
+               ctx = ntfs_attr_get_search_ctx(base_ni, m);
+               if (unlikely(!ctx)) {
+                       err = -ENOMEM;
+                       goto err_out;
+               }
+               err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+                               CASE_SENSITIVE, 0, NULL, 0, ctx);
+               if (unlikely(err)) {
+                       if (err == -ENOENT)
+                               err = -EIO;
+                       goto err_out;
+               }
+               m = ctx->mrec;
+               a = ctx->attr;
+               BUG_ON(!a->non_resident);
+               BUG_ON(old_i_size != (loff_t)
+                               sle64_to_cpu(a->data.non_resident.data_size));
+               a->data.non_resident.data_size = cpu_to_sle64(new_init_size);
+               flush_dcache_mft_record_page(ctx->ntfs_ino);
+               mark_mft_record_dirty(ctx->ntfs_ino);
+               /* Update the file size in the vfs inode. */
+               i_size_write(vi, new_init_size);
+               ntfs_attr_put_search_ctx(ctx);
+               ctx = NULL;
+               unmap_mft_record(base_ni);
+               m = NULL;
+       }
+       mapping = vi->i_mapping;
+       index = old_init_size >> PAGE_CACHE_SHIFT;
+       end_index = (new_init_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+       do {
+               /*
+                * Read the page.  If the page is not present, this will zero
+                * the uninitialized regions for us.
+                */
+               page = read_cache_page(mapping, index,
+                               (filler_t*)mapping->a_ops->readpage, NULL);
+               if (IS_ERR(page)) {
+                       err = PTR_ERR(page);
+                       goto init_err_out;
+               }
+               wait_on_page_locked(page);
+               if (unlikely(!PageUptodate(page) || PageError(page))) {
+                       page_cache_release(page);
+                       err = -EIO;
+                       goto init_err_out;
+               }
+               /*
+                * Update the initialized size in the ntfs inode.  This is
+                * enough to make ntfs_writepage() work.
+                */
+               write_lock_irqsave(&ni->size_lock, flags);
+               ni->initialized_size = (index + 1) << PAGE_CACHE_SHIFT;
+               if (ni->initialized_size > new_init_size)
+                       ni->initialized_size = new_init_size;
+               write_unlock_irqrestore(&ni->size_lock, flags);
+               /* Set the page dirty so it gets written out. */
+               set_page_dirty(page);
+               page_cache_release(page);
+               /*
+                * Play nice with the vm and the rest of the system.  This is
+                * very much needed as we can potentially be modifying the
+                * initialised size from a very small value to a really huge
+                * value, e.g.
+                *      f = open(somefile, O_TRUNC);
+                *      truncate(f, 10GiB);
+                *      seek(f, 10GiB);
+                *      write(f, 1);
+                * And this would mean we would be marking dirty hundreds of
+                * thousands of pages or as in the above example more than
+                * two and a half million pages!
+                *
+                * TODO: For sparse pages could optimize this workload by using
+                * the FsMisc / MiscFs page bit as a "PageIsSparse" bit.  This
+                * would be set in readpage for sparse pages and here we would
+                * not need to mark dirty any pages which have this bit set.
+                * The only caveat is that we have to clear the bit everywhere
+                * where we allocate any clusters that lie in the page or that
+                * contain the page.
+                *
+                * TODO: An even greater optimization would be for us to only
+                * call readpage() on pages which are not in sparse regions as
+                * determined from the runlist.  This would greatly reduce the
+                * number of pages we read and make dirty in the case of sparse
+                * files.
+                */
+               balance_dirty_pages_ratelimited(mapping);
+               cond_resched();
+       } while (++index < end_index);
+       read_lock_irqsave(&ni->size_lock, flags);
+       BUG_ON(ni->initialized_size != new_init_size);
+       read_unlock_irqrestore(&ni->size_lock, flags);
+       /* Now bring in sync the initialized_size in the mft record. */
+       m = map_mft_record(base_ni);
+       if (IS_ERR(m)) {
+               err = PTR_ERR(m);
+               m = NULL;
+               goto init_err_out;
+       }
+       ctx = ntfs_attr_get_search_ctx(base_ni, m);
+       if (unlikely(!ctx)) {
+               err = -ENOMEM;
+               goto init_err_out;
+       }
+       err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+                       CASE_SENSITIVE, 0, NULL, 0, ctx);
+       if (unlikely(err)) {
+               if (err == -ENOENT)
+                       err = -EIO;
+               goto init_err_out;
+       }
+       m = ctx->mrec;
+       a = ctx->attr;
+       BUG_ON(!a->non_resident);
+       a->data.non_resident.initialized_size = cpu_to_sle64(new_init_size);
+done:
+       flush_dcache_mft_record_page(ctx->ntfs_ino);
+       mark_mft_record_dirty(ctx->ntfs_ino);
+       if (ctx)
+               ntfs_attr_put_search_ctx(ctx);
+       if (m)
+               unmap_mft_record(base_ni);
+       ntfs_debug("Done, initialized_size 0x%llx, i_size 0x%llx.",
+                       (unsigned long long)new_init_size, i_size_read(vi));
+       return 0;
+init_err_out:
+       write_lock_irqsave(&ni->size_lock, flags);
+       ni->initialized_size = old_init_size;
+       write_unlock_irqrestore(&ni->size_lock, flags);
+err_out:
+       if (ctx)
+               ntfs_attr_put_search_ctx(ctx);
+       if (m)
+               unmap_mft_record(base_ni);
+       ntfs_debug("Failed.  Returning error code %i.", err);
+       return err;
+}
+
+/**
+ * ntfs_fault_in_pages_readable -
+ *
+ * Fault a number of userspace pages into pagetables.
+ *
+ * Unlike include/linux/pagemap.h::fault_in_pages_readable(), this one copes
+ * with more than two userspace pages as well as handling the single page case
+ * elegantly.
+ *
+ * If you find this difficult to understand, then think of the while loop being
+ * the following code, except that we do without the integer variable ret:
+ *
+ *     do {
+ *             ret = __get_user(c, uaddr);
+ *             uaddr += PAGE_SIZE;
+ *     } while (!ret && uaddr < end);
+ *
+ * Note, the final __get_user() may well run out-of-bounds of the user buffer,
+ * but _not_ out-of-bounds of the page the user buffer belongs to, and since
+ * this is only a read and not a write, and since it is still in the same page,
+ * it should not matter and this makes the code much simpler.
+ */
+static inline void ntfs_fault_in_pages_readable(const char __user *uaddr,
+               int bytes)
+{
+       const char __user *end;
+       volatile char c;
+
+       /* Set @end to the first byte outside the last page we care about. */
+       end = (const char __user*)PAGE_ALIGN((ptrdiff_t __user)uaddr + bytes);
+
+       while (!__get_user(c, uaddr) && (uaddr += PAGE_SIZE, uaddr < end))
+               ;
+}
+
+/**
+ * ntfs_fault_in_pages_readable_iovec -
+ *
+ * Same as ntfs_fault_in_pages_readable() but operates on an array of iovecs.
+ */
+static inline void ntfs_fault_in_pages_readable_iovec(const struct iovec *iov,
+               size_t iov_ofs, int bytes)
+{
+       do {
+               const char __user *buf;
+               unsigned len;
+
+               buf = iov->iov_base + iov_ofs;
+               len = iov->iov_len - iov_ofs;
+               if (len > bytes)
+                       len = bytes;
+               ntfs_fault_in_pages_readable(buf, len);
+               bytes -= len;
+               iov++;
+               iov_ofs = 0;
+       } while (bytes);
+}
+
+/**
+ * __ntfs_grab_cache_pages - obtain a number of locked pages
+ * @mapping:   address space mapping from which to obtain page cache pages
+ * @index:     starting index in @mapping at which to begin obtaining pages
+ * @nr_pages:  number of page cache pages to obtain
+ * @pages:     array of pages in which to return the obtained page cache pages
+ * @cached_page: allocated but as yet unused page
+ * @lru_pvec:  lru-buffering pagevec of caller
+ *
+ * Obtain @nr_pages locked page cache pages from the mapping @maping and
+ * starting at index @index.
+ *
+ * If a page is newly created, increment its refcount and add it to the
+ * caller's lru-buffering pagevec @lru_pvec.
+ *
+ * This is the same as mm/filemap.c::__grab_cache_page(), except that @nr_pages
+ * are obtained at once instead of just one page and that 0 is returned on
+ * success and -errno on error.
+ *
+ * Note, the page locks are obtained in ascending page index order.
+ */
+static inline int __ntfs_grab_cache_pages(struct address_space *mapping,
+               pgoff_t index, const unsigned nr_pages, struct page **pages,
+               struct page **cached_page, struct pagevec *lru_pvec)
+{
+       int err, nr;
+
+       BUG_ON(!nr_pages);
+       err = nr = 0;
+       do {
+               pages[nr] = find_lock_page(mapping, index);
+               if (!pages[nr]) {
+                       if (!*cached_page) {
+                               *cached_page = page_cache_alloc(mapping);
+                               if (unlikely(!*cached_page)) {
+                                       err = -ENOMEM;
+                                       goto err_out;
+                               }
+                       }
+                       err = add_to_page_cache(*cached_page, mapping, index,
+                                       GFP_KERNEL);
+                       if (unlikely(err)) {
+                               if (err == -EEXIST)
+                                       continue;
+                               goto err_out;
+                       }
+                       pages[nr] = *cached_page;
+                       page_cache_get(*cached_page);
+                       if (unlikely(!pagevec_add(lru_pvec, *cached_page)))
+                               __pagevec_lru_add(lru_pvec);
+                       *cached_page = NULL;
+               }
+               index++;
+               nr++;
+       } while (nr < nr_pages);
+out:
+       return err;
+err_out:
+       while (nr > 0) {
+               unlock_page(pages[--nr]);
+               page_cache_release(pages[nr]);
+       }
+       goto out;
+}
+
+static inline int ntfs_submit_bh_for_read(struct buffer_head *bh)
+{
+       lock_buffer(bh);
+       get_bh(bh);
+       bh->b_end_io = end_buffer_read_sync;
+       return submit_bh(READ, bh);
+}
+
+/**
+ * ntfs_prepare_pages_for_non_resident_write - prepare pages for receiving data
+ * @pages:     array of destination pages
+ * @nr_pages:  number of pages in @pages
+ * @pos:       byte position in file at which the write begins
+ * @bytes:     number of bytes to be written
+ *
+ * This is called for non-resident attributes from ntfs_file_buffered_write()
+ * with i_sem held on the inode (@pages[0]->mapping->host).  There are
+ * @nr_pages pages in @pages which are locked but not kmap()ped.  The source
+ * data has not yet been copied into the @pages.
+ * 
+ * Need to fill any holes with actual clusters, allocate buffers if necessary,
+ * ensure all the buffers are mapped, and bring uptodate any buffers that are
+ * only partially being written to.
+ *
+ * If @nr_pages is greater than one, we are guaranteed that the cluster size is
+ * greater than PAGE_CACHE_SIZE, that all pages in @pages are entirely inside
+ * the same cluster and that they are the entirety of that cluster, and that
+ * the cluster is sparse, i.e. we need to allocate a cluster to fill the hole.
+ *
+ * i_size is not to be modified yet.
+ *
+ * Return 0 on success or -errno on error.
+ */
+static int ntfs_prepare_pages_for_non_resident_write(struct page **pages,
+               unsigned nr_pages, s64 pos, size_t bytes)
+{
+       VCN vcn, highest_vcn = 0, cpos, cend, bh_cpos, bh_cend;
+       LCN lcn;
+       s64 bh_pos, vcn_len, end, initialized_size;
+       sector_t lcn_block;
+       struct page *page;
+       struct inode *vi;
+       ntfs_inode *ni, *base_ni = NULL;
+       ntfs_volume *vol;
+       runlist_element *rl, *rl2;
+       struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
+       ntfs_attr_search_ctx *ctx = NULL;
+       MFT_RECORD *m = NULL;
+       ATTR_RECORD *a = NULL;
+       unsigned long flags;
+       u32 attr_rec_len = 0;
+       unsigned blocksize, u;
+       int err, mp_size;
+       BOOL rl_write_locked, was_hole, is_retry;
+       unsigned char blocksize_bits;
+       struct {
+               u8 runlist_merged:1;
+               u8 mft_attr_mapped:1;
+               u8 mp_rebuilt:1;
+               u8 attr_switched:1;
+       } status = { 0, 0, 0, 0 };
+
+       BUG_ON(!nr_pages);
+       BUG_ON(!pages);
+       BUG_ON(!*pages);
+       vi = pages[0]->mapping->host;
+       ni = NTFS_I(vi);
+       vol = ni->vol;
+       ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, start page "
+                       "index 0x%lx, nr_pages 0x%x, pos 0x%llx, bytes 0x%x.",
+                       vi->i_ino, ni->type, pages[0]->index, nr_pages,
+                       (long long)pos, bytes);
+       blocksize_bits = vi->i_blkbits;
+       blocksize = 1 << blocksize_bits;
+       u = 0;
+       do {
+               struct page *page = pages[u];
+               /*
+                * create_empty_buffers() will create uptodate/dirty buffers if
+                * the page is uptodate/dirty.
+                */
+               if (!page_has_buffers(page)) {
+                       create_empty_buffers(page, blocksize, 0);
+                       if (unlikely(!page_has_buffers(page)))
+                               return -ENOMEM;
+               }
+       } while (++u < nr_pages);
+       rl_write_locked = FALSE;
+       rl = NULL;
+       err = 0;
+       vcn = lcn = -1;
+       vcn_len = 0;
+       lcn_block = -1;
+       was_hole = FALSE;
+       cpos = pos >> vol->cluster_size_bits;
+       end = pos + bytes;
+       cend = (end + vol->cluster_size - 1) >> vol->cluster_size_bits;
+       /*
+        * Loop over each page and for each page over each buffer.  Use goto to
+        * reduce indentation.
+        */
+       u = 0;
+do_next_page:
+       page = pages[u];
+       bh_pos = (s64)page->index << PAGE_CACHE_SHIFT;
+       bh = head = page_buffers(page);
+       do {
+               VCN cdelta;
+               s64 bh_end;
+               unsigned bh_cofs;
+
+               /* Clear buffer_new on all buffers to reinitialise state. */
+               if (buffer_new(bh))
+                       clear_buffer_new(bh);
+               bh_end = bh_pos + blocksize;
+               bh_cpos = bh_pos >> vol->cluster_size_bits;
+               bh_cofs = bh_pos & vol->cluster_size_mask;
+               if (buffer_mapped(bh)) {
+                       /*
+                        * The buffer is already mapped.  If it is uptodate,
+                        * ignore it.
+                        */
+                       if (buffer_uptodate(bh))
+                               continue;
+                       /*
+                        * The buffer is not uptodate.  If the page is uptodate
+                        * set the buffer uptodate and otherwise ignore it.
+                        */
+                       if (PageUptodate(page)) {
+                               set_buffer_uptodate(bh);
+                               continue;
+                       }
+                       /*
+                        * Neither the page nor the buffer are uptodate.  If
+                        * the buffer is only partially being written to, we
+                        * need to read it in before the write, i.e. now.
+                        */
+                       if ((bh_pos < pos && bh_end > pos) ||
+                                       (bh_pos < end && bh_end > end)) {
+                               /*
+                                * If the buffer is fully or partially within
+                                * the initialized size, do an actual read.
+                                * Otherwise, simply zero the buffer.
+                                */
+                               read_lock_irqsave(&ni->size_lock, flags);
+                               initialized_size = ni->initialized_size;
+                               read_unlock_irqrestore(&ni->size_lock, flags);
+                               if (bh_pos < initialized_size) {
+                                       ntfs_submit_bh_for_read(bh);
+                                       *wait_bh++ = bh;
+                               } else {
+                                       u8 *kaddr = kmap_atomic(page, KM_USER0);
+                                       memset(kaddr + bh_offset(bh), 0,
+                                                       blocksize);
+                                       kunmap_atomic(kaddr, KM_USER0);
+                                       flush_dcache_page(page);
+                                       set_buffer_uptodate(bh);
+                               }
+                       }
+                       continue;
+               }
+               /* Unmapped buffer.  Need to map it. */
+               bh->b_bdev = vol->sb->s_bdev;
+               /*
+                * If the current buffer is in the same clusters as the map
+                * cache, there is no need to check the runlist again.  The
+                * map cache is made up of @vcn, which is the first cached file
+                * cluster, @vcn_len which is the number of cached file
+                * clusters, @lcn is the device cluster corresponding to @vcn,
+                * and @lcn_block is the block number corresponding to @lcn.
+                */
+               cdelta = bh_cpos - vcn;
+               if (likely(!cdelta || (cdelta > 0 && cdelta < vcn_len))) {
+map_buffer_cached:
+                       BUG_ON(lcn < 0);
+                       bh->b_blocknr = lcn_block +
+                                       (cdelta << (vol->cluster_size_bits -
+                                       blocksize_bits)) +
+                                       (bh_cofs >> blocksize_bits);
+                       set_buffer_mapped(bh);
+                       /*
+                        * If the page is uptodate so is the buffer.  If the
+                        * buffer is fully outside the write, we ignore it if
+                        * it was already allocated and we mark it dirty so it
+                        * gets written out if we allocated it.  On the other
+                        * hand, if we allocated the buffer but we are not
+                        * marking it dirty we set buffer_new so we can do
+                        * error recovery.
+                        */
+                       if (PageUptodate(page)) {
+                               if (!buffer_uptodate(bh))
+                                       set_buffer_uptodate(bh);
+                               if (unlikely(was_hole)) {
+                                       /* We allocated the buffer. */
+                                       unmap_underlying_metadata(bh->b_bdev,
+                                                       bh->b_blocknr);
+                                       if (bh_end <= pos || bh_pos >= end)
+                                               mark_buffer_dirty(bh);
+                                       else
+                                               set_buffer_new(bh);
+                               }
+                               continue;
+                       }
+                       /* Page is _not_ uptodate. */
+                       if (likely(!was_hole)) {
+                               /*
+                                * Buffer was already allocated.  If it is not
+                                * uptodate and is only partially being written
+                                * to, we need to read it in before the write,
+                                * i.e. now.
+                                */
+                               if (!buffer_uptodate(bh) && ((bh_pos < pos &&
+                                               bh_end > pos) ||
+                                               (bh_end > end &&
+                                               bh_end > end))) {
+                                       /*
+                                        * If the buffer is fully or partially
+                                        * within the initialized size, do an
+                                        * actual read.  Otherwise, simply zero
+                                        * the buffer.
+                                        */
+                                       read_lock_irqsave(&ni->size_lock,
+                                                       flags);
+                                       initialized_size = ni->initialized_size;
+                                       read_unlock_irqrestore(&ni->size_lock,
+                                                       flags);
+                                       if (bh_pos < initialized_size) {
+                                               ntfs_submit_bh_for_read(bh);
+                                               *wait_bh++ = bh;
+                                       } else {
+                                               u8 *kaddr = kmap_atomic(page,
+                                                               KM_USER0);
+                                               memset(kaddr + bh_offset(bh),
+                                                               0, blocksize);
+                                               kunmap_atomic(kaddr, KM_USER0);
+                                               flush_dcache_page(page);
+                                               set_buffer_uptodate(bh);
+                                       }
+                               }
+                               continue;
+                       }
+                       /* We allocated the buffer. */
+                       unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
+                       /*
+                        * If the buffer is fully outside the write, zero it,
+                        * set it uptodate, and mark it dirty so it gets
+                        * written out.  If it is partially being written to,
+                        * zero region surrounding the write but leave it to
+                        * commit write to do anything else.  Finally, if the
+                        * buffer is fully being overwritten, do nothing.
+                        */
+                       if (bh_end <= pos || bh_pos >= end) {
+                               if (!buffer_uptodate(bh)) {
+                                       u8 *kaddr = kmap_atomic(page, KM_USER0);
+                                       memset(kaddr + bh_offset(bh), 0,
+                                                       blocksize);
+                                       kunmap_atomic(kaddr, KM_USER0);
+                                       flush_dcache_page(page);
+                                       set_buffer_uptodate(bh);
+                               }
+                               mark_buffer_dirty(bh);
+                               continue;
+                       }
+                       set_buffer_new(bh);
+                       if (!buffer_uptodate(bh) &&
+                                       (bh_pos < pos || bh_end > end)) {
+                               u8 *kaddr;
+                               unsigned pofs;
+                                       
+                               kaddr = kmap_atomic(page, KM_USER0);
+                               if (bh_pos < pos) {
+                                       pofs = bh_pos & ~PAGE_CACHE_MASK;
+                                       memset(kaddr + pofs, 0, pos - bh_pos);
+                               }
+                               if (bh_end > end) {
+                                       pofs = end & ~PAGE_CACHE_MASK;
+                                       memset(kaddr + pofs, 0, bh_end - end);
+                               }
+                               kunmap_atomic(kaddr, KM_USER0);
+                               flush_dcache_page(page);
+                       }
+                       continue;
+               }
+               /*
+                * Slow path: this is the first buffer in the cluster.  If it
+                * is outside allocated size and is not uptodate, zero it and
+                * set it uptodate.
+                */
+               read_lock_irqsave(&ni->size_lock, flags);
+               initialized_size = ni->allocated_size;
+               read_unlock_irqrestore(&ni->size_lock, flags);
+               if (bh_pos > initialized_size) {
+                       if (PageUptodate(page)) {
+                               if (!buffer_uptodate(bh))
+                                       set_buffer_uptodate(bh);
+                       } else if (!buffer_uptodate(bh)) {
+                               u8 *kaddr = kmap_atomic(page, KM_USER0);
+                               memset(kaddr + bh_offset(bh), 0, blocksize);
+                               kunmap_atomic(kaddr, KM_USER0);
+                               flush_dcache_page(page);
+                               set_buffer_uptodate(bh);
+                       }
+                       continue;
+               }
+               is_retry = FALSE;
+               if (!rl) {
+                       down_read(&ni->runlist.lock);
+retry_remap:
+                       rl = ni->runlist.rl;
+               }
+               if (likely(rl != NULL)) {
+                       /* Seek to element containing target cluster. */
+                       while (rl->length && rl[1].vcn <= bh_cpos)
+                               rl++;
+                       lcn = ntfs_rl_vcn_to_lcn(rl, bh_cpos);
+                       if (likely(lcn >= 0)) {
+                               /*
+                                * Successful remap, setup the map cache and
+                                * use that to deal with the buffer.
+                                */
+                               was_hole = FALSE;
+                               vcn = bh_cpos;
+                               vcn_len = rl[1].vcn - vcn;
+                               lcn_block = lcn << (vol->cluster_size_bits -
+                                               blocksize_bits);
+                               /*
+                                * If the number of remaining clusters in the
+                                * @pages is smaller or equal to the number of
+                                * cached clusters, unlock the runlist as the
+                                * map cache will be used from now on.
+                                */
+                               if (likely(vcn + vcn_len >= cend)) {
+                                       if (rl_write_locked) {
+                                               up_write(&ni->runlist.lock);
+                                               rl_write_locked = FALSE;
+                                       } else
+                                               up_read(&ni->runlist.lock);
+                                       rl = NULL;
+                               }
+                               goto map_buffer_cached;
+                       }
+               } else
+                       lcn = LCN_RL_NOT_MAPPED;
+               /*
+                * If it is not a hole and not out of bounds, the runlist is
+                * probably unmapped so try to map it now.
+                */
+               if (unlikely(lcn != LCN_HOLE && lcn != LCN_ENOENT)) {
+                       if (likely(!is_retry && lcn == LCN_RL_NOT_MAPPED)) {
+                               /* Attempt to map runlist. */
+                               if (!rl_write_locked) {
+                                       /*
+                                        * We need the runlist locked for
+                                        * writing, so if it is locked for
+                                        * reading relock it now and retry in
+                                        * case it changed whilst we dropped
+                                        * the lock.
+                                        */
+                                       up_read(&ni->runlist.lock);
+                                       down_write(&ni->runlist.lock);
+                                       rl_write_locked = TRUE;
+                                       goto retry_remap;
+                               }
+                               err = ntfs_map_runlist_nolock(ni, bh_cpos,
+                                               NULL);
+                               if (likely(!err)) {
+                                       is_retry = TRUE;
+                                       goto retry_remap;
+                               }
+                               /*
+                                * If @vcn is out of bounds, pretend @lcn is
+                                * LCN_ENOENT.  As long as the buffer is out
+                                * of bounds this will work fine.
+                                */
+                               if (err == -ENOENT) {
+                                       lcn = LCN_ENOENT;
+                                       err = 0;
+                                       goto rl_not_mapped_enoent;
+                               }
+                       } else
+                               err = -EIO;
+                       /* Failed to map the buffer, even after retrying. */
+                       bh->b_blocknr = -1;
+                       ntfs_error(vol->sb, "Failed to write to inode 0x%lx, "
+                                       "attribute type 0x%x, vcn 0x%llx, "
+                                       "vcn offset 0x%x, because its "
+                                       "location on disk could not be "
+                                       "determined%s (error code %i).",
+                                       ni->mft_no, ni->type,
+                                       (unsigned long long)bh_cpos,
+                                       (unsigned)bh_pos &
+                                       vol->cluster_size_mask,
+                                       is_retry ? " even after retrying" : "",
+                                       err);
+                       break;
+               }
+rl_not_mapped_enoent:
+               /*
+                * The buffer is in a hole or out of bounds.  We need to fill
+                * the hole, unless the buffer is in a cluster which is not
+                * touched by the write, in which case we just leave the buffer
+                * unmapped.  This can only happen when the cluster size is
+                * less than the page cache size.
+                */
+               if (unlikely(vol->cluster_size < PAGE_CACHE_SIZE)) {
+                       bh_cend = (bh_end + vol->cluster_size - 1) >>
+                                       vol->cluster_size_bits;
+                       if ((bh_cend <= cpos || bh_cpos >= cend)) {
+                               bh->b_blocknr = -1;
+                               /*
+                                * If the buffer is uptodate we skip it.  If it
+                                * is not but the page is uptodate, we can set
+                                * the buffer uptodate.  If the page is not
+                                * uptodate, we can clear the buffer and set it
+                                * uptodate.  Whether this is worthwhile is
+                                * debatable and this could be removed.
+                                */
+                               if (PageUptodate(page)) {
+                                       if (!buffer_uptodate(bh))
+                                               set_buffer_uptodate(bh);
+                               } else if (!buffer_uptodate(bh)) {
+                                       u8 *kaddr = kmap_atomic(page, KM_USER0);
+                                       memset(kaddr + bh_offset(bh), 0,
+                                                       blocksize);
+                                       kunmap_atomic(kaddr, KM_USER0);
+                                       flush_dcache_page(page);
+                                       set_buffer_uptodate(bh);
+                               }
+                               continue;
+                       }
+               }
+               /*
+                * Out of bounds buffer is invalid if it was not really out of
+                * bounds.
+                */
+               BUG_ON(lcn != LCN_HOLE);
+               /*
+                * We need the runlist locked for writing, so if it is locked
+                * for reading relock it now and retry in case it changed
+                * whilst we dropped the lock.
+                */
+               BUG_ON(!rl);
+               if (!rl_write_locked) {
+                       up_read(&ni->runlist.lock);
+                       down_write(&ni->runlist.lock);
+                       rl_write_locked = TRUE;
+                       goto retry_remap;
+               }
+               /* Find the previous last allocated cluster. */
+               BUG_ON(rl->lcn != LCN_HOLE);
+               lcn = -1;
+               rl2 = rl;
+               while (--rl2 >= ni->runlist.rl) {
+                       if (rl2->lcn >= 0) {
+                               lcn = rl2->lcn + rl2->length;
+                               break;
+                       }
+               }
+               rl2 = ntfs_cluster_alloc(vol, bh_cpos, 1, lcn, DATA_ZONE,
+                               FALSE);
+               if (IS_ERR(rl2)) {
+                       err = PTR_ERR(rl2);
+                       ntfs_debug("Failed to allocate cluster, error code %i.",
+                                       err);
+                       break;
+               }
+               lcn = rl2->lcn;
+               rl = ntfs_runlists_merge(ni->runlist.rl, rl2);
+               if (IS_ERR(rl)) {
+                       err = PTR_ERR(rl);
+                       if (err != -ENOMEM)
+                               err = -EIO;
+                       if (ntfs_cluster_free_from_rl(vol, rl2)) {
+                               ntfs_error(vol->sb, "Failed to release "
+                                               "allocated cluster in error "
+                                               "code path.  Run chkdsk to "
+                                               "recover the lost cluster.");
+                               NVolSetErrors(vol);
+                       }
+                       ntfs_free(rl2);
+                       break;
+               }
+               ni->runlist.rl = rl;
+               status.runlist_merged = 1;
+               ntfs_debug("Allocated cluster, lcn 0x%llx.", lcn);
+               /* Map and lock the mft record and get the attribute record. */
+               if (!NInoAttr(ni))
+                       base_ni = ni;
+               else
+                       base_ni = ni->ext.base_ntfs_ino;
+               m = map_mft_record(base_ni);
+               if (IS_ERR(m)) {
+                       err = PTR_ERR(m);
+                       break;
+               }
+               ctx = ntfs_attr_get_search_ctx(base_ni, m);
+               if (unlikely(!ctx)) {
+                       err = -ENOMEM;
+                       unmap_mft_record(base_ni);
+                       break;
+               }
+               status.mft_attr_mapped = 1;
+               err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+                               CASE_SENSITIVE, bh_cpos, NULL, 0, ctx);
+               if (unlikely(err)) {
+                       if (err == -ENOENT)
+                               err = -EIO;
+                       break;
+               }
+               m = ctx->mrec;
+               a = ctx->attr;
+               /*
+                * Find the runlist element with which the attribute extent
+                * starts.  Note, we cannot use the _attr_ version because we
+                * have mapped the mft record.  That is ok because we know the
+                * runlist fragment must be mapped already to have ever gotten
+                * here, so we can just use the _rl_ version.
+                */
+               vcn = sle64_to_cpu(a->data.non_resident.lowest_vcn);
+               rl2 = ntfs_rl_find_vcn_nolock(rl, vcn);
+               BUG_ON(!rl2);
+               BUG_ON(!rl2->length);
+               BUG_ON(rl2->lcn < LCN_HOLE);
+               highest_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn);
+               /*
+                * If @highest_vcn is zero, calculate the real highest_vcn
+                * (which can really be zero).
+                */
+               if (!highest_vcn)
+                       highest_vcn = (sle64_to_cpu(
+                                       a->data.non_resident.allocated_size) >>
+                                       vol->cluster_size_bits) - 1;
+               /*
+                * Determine the size of the mapping pairs array for the new
+                * extent, i.e. the old extent with the hole filled.
+                */
+               mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, vcn,
+                               highest_vcn);
+               if (unlikely(mp_size <= 0)) {
+                       if (!(err = mp_size))
+                               err = -EIO;
+                       ntfs_debug("Failed to get size for mapping pairs "
+                                       "array, error code %i.", err);
+                       break;
+               }
+               /*
+                * Resize the attribute record to fit the new mapping pairs
+                * array.
+                */
+               attr_rec_len = le32_to_cpu(a->length);
+               err = ntfs_attr_record_resize(m, a, mp_size + le16_to_cpu(
+                               a->data.non_resident.mapping_pairs_offset));
+               if (unlikely(err)) {
+                       BUG_ON(err != -ENOSPC);
+                       // TODO: Deal with this by using the current attribute
+                       // and fill it with as much of the mapping pairs
+                       // array as possible.  Then loop over each attribute
+                       // extent rewriting the mapping pairs arrays as we go
+                       // along and if when we reach the end we have not
+                       // enough space, try to resize the last attribute
+                       // extent and if even that fails, add a new attribute
+                       // extent.
+                       // We could also try to resize at each step in the hope
+                       // that we will not need to rewrite every single extent.
+                       // Note, we may need to decompress some extents to fill
+                       // the runlist as we are walking the extents...
+                       ntfs_error(vol->sb, "Not enough space in the mft "
+                                       "record for the extended attribute "
+                                       "record.  This case is not "
+                                       "implemented yet.");
+                       err = -EOPNOTSUPP;
+                       break ;
+               }
+               status.mp_rebuilt = 1;
+               /*
+                * Generate the mapping pairs array directly into the attribute
+                * record.
+                */
+               err = ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
+                               a->data.non_resident.mapping_pairs_offset),
+                               mp_size, rl2, vcn, highest_vcn, NULL);
+               if (unlikely(err)) {
+                       ntfs_error(vol->sb, "Cannot fill hole in inode 0x%lx, "
+                                       "attribute type 0x%x, because building "
+                                       "the mapping pairs failed with error "
+                                       "code %i.", vi->i_ino,
+                                       (unsigned)le32_to_cpu(ni->type), err);
+                       err = -EIO;
+                       break;
+               }
+               /* Update the highest_vcn but only if it was not set. */
+               if (unlikely(!a->data.non_resident.highest_vcn))
+                       a->data.non_resident.highest_vcn =
+                                       cpu_to_sle64(highest_vcn);
+               /*
+                * If the attribute is sparse/compressed, update the compressed
+                * size in the ntfs_inode structure and the attribute record.
+                */
+               if (likely(NInoSparse(ni) || NInoCompressed(ni))) {
+                       /*
+                        * If we are not in the first attribute extent, switch
+                        * to it, but first ensure the changes will make it to
+                        * disk later.
+                        */
+                       if (a->data.non_resident.lowest_vcn) {
+                               flush_dcache_mft_record_page(ctx->ntfs_ino);
+                               mark_mft_record_dirty(ctx->ntfs_ino);
+                               ntfs_attr_reinit_search_ctx(ctx);
+                               err = ntfs_attr_lookup(ni->type, ni->name,
+                                               ni->name_len, CASE_SENSITIVE,
+                                               0, NULL, 0, ctx);
+                               if (unlikely(err)) {
+                                       status.attr_switched = 1;
+                                       break;
+                               }
+                               /* @m is not used any more so do not set it. */
+                               a = ctx->attr;
+                       }
+                       write_lock_irqsave(&ni->size_lock, flags);
+                       ni->itype.compressed.size += vol->cluster_size;
+                       a->data.non_resident.compressed_size =
+                                       cpu_to_sle64(ni->itype.compressed.size);
+                       write_unlock_irqrestore(&ni->size_lock, flags);
+               }
+               /* Ensure the changes make it to disk. */
+               flush_dcache_mft_record_page(ctx->ntfs_ino);
+               mark_mft_record_dirty(ctx->ntfs_ino);
+               ntfs_attr_put_search_ctx(ctx);
+               unmap_mft_record(base_ni);
+               /* Successfully filled the hole. */
+               status.runlist_merged = 0;
+               status.mft_attr_mapped = 0;
+               status.mp_rebuilt = 0;
+               /* Setup the map cache and use that to deal with the buffer. */
+               was_hole = TRUE;
+               vcn = bh_cpos;
+               vcn_len = 1;
+               lcn_block = lcn << (vol->cluster_size_bits - blocksize_bits);
+               cdelta = 0;
+               /*
+                * If the number of remaining clusters in the @pages is smaller
+                * or equal to the number of cached clusters, unlock the
+                * runlist as the map cache will be used from now on.
+                */
+               if (likely(vcn + vcn_len >= cend)) {
+                       up_write(&ni->runlist.lock);
+                       rl_write_locked = FALSE;
+                       rl = NULL;
+               }
+               goto map_buffer_cached;
+       } while (bh_pos += blocksize, (bh = bh->b_this_page) != head);
+       /* If there are no errors, do the next page. */
+       if (likely(!err && ++u < nr_pages))
+               goto do_next_page;
+       /* If there are no errors, release the runlist lock if we took it. */
+       if (likely(!err)) {
+               if (unlikely(rl_write_locked)) {
+                       up_write(&ni->runlist.lock);
+                       rl_write_locked = FALSE;
+               } else if (unlikely(rl))
+                       up_read(&ni->runlist.lock);
+               rl = NULL;
+       }
+       /* If we issued read requests, let them complete. */
+       read_lock_irqsave(&ni->size_lock, flags);
+       initialized_size = ni->initialized_size;
+       read_unlock_irqrestore(&ni->size_lock, flags);
+       while (wait_bh > wait) {
+               bh = *--wait_bh;
+               wait_on_buffer(bh);
+               if (likely(buffer_uptodate(bh))) {
+                       page = bh->b_page;
+                       bh_pos = ((s64)page->index << PAGE_CACHE_SHIFT) +
+                                       bh_offset(bh);
+                       /*
+                        * If the buffer overflows the initialized size, need
+                        * to zero the overflowing region.
+                        */
+                       if (unlikely(bh_pos + blocksize > initialized_size)) {
+                               u8 *kaddr;
+                               int ofs = 0;
+
+                               if (likely(bh_pos < initialized_size))
+                                       ofs = initialized_size - bh_pos;
+                               kaddr = kmap_atomic(page, KM_USER0);
+                               memset(kaddr + bh_offset(bh) + ofs, 0,
+                                               blocksize - ofs);
+                               kunmap_atomic(kaddr, KM_USER0);
+                               flush_dcache_page(page);
+                       }
+               } else /* if (unlikely(!buffer_uptodate(bh))) */
+                       err = -EIO;
+       }
+       if (likely(!err)) {
+               /* Clear buffer_new on all buffers. */
+               u = 0;
+               do {
+                       bh = head = page_buffers(pages[u]);
+                       do {
+                               if (buffer_new(bh))
+                                       clear_buffer_new(bh);
+                       } while ((bh = bh->b_this_page) != head);
+               } while (++u < nr_pages);
+               ntfs_debug("Done.");
+               return err;
+       }
+       if (status.attr_switched) {
+               /* Get back to the attribute extent we modified. */
+               ntfs_attr_reinit_search_ctx(ctx);
+               if (ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+                               CASE_SENSITIVE, bh_cpos, NULL, 0, ctx)) {
+                       ntfs_error(vol->sb, "Failed to find required "
+                                       "attribute extent of attribute in "
+                                       "error code path.  Run chkdsk to "
+                                       "recover.");
+                       write_lock_irqsave(&ni->size_lock, flags);
+                       ni->itype.compressed.size += vol->cluster_size;
+                       write_unlock_irqrestore(&ni->size_lock, flags);
+                       flush_dcache_mft_record_page(ctx->ntfs_ino);
+                       mark_mft_record_dirty(ctx->ntfs_ino);
+                       /*
+                        * The only thing that is now wrong is the compressed
+                        * size of the base attribute extent which chkdsk
+                        * should be able to fix.
+                        */
+                       NVolSetErrors(vol);
+               } else {
+                       m = ctx->mrec;
+                       a = ctx->attr;
+                       status.attr_switched = 0;
+               }
+       }
+       /*
+        * If the runlist has been modified, need to restore it by punching a
+        * hole into it and we then need to deallocate the on-disk cluster as
+        * well.  Note, we only modify the runlist if we are able to generate a
+        * new mapping pairs array, i.e. only when the mapped attribute extent
+        * is not switched.
+        */
+       if (status.runlist_merged && !status.attr_switched) {
+               BUG_ON(!rl_write_locked);
+               /* Make the file cluster we allocated sparse in the runlist. */
+               if (ntfs_rl_punch_nolock(vol, &ni->runlist, bh_cpos, 1)) {
+                       ntfs_error(vol->sb, "Failed to punch hole into "
+                                       "attribute runlist in error code "
+                                       "path.  Run chkdsk to recover the "
+                                       "lost cluster.");
+                       make_bad_inode(vi);
+                       make_bad_inode(VFS_I(base_ni));
+                       NVolSetErrors(vol);
+               } else /* if (success) */ {
+                       status.runlist_merged = 0;
+                       /*
+                        * Deallocate the on-disk cluster we allocated but only
+                        * if we succeeded in punching its vcn out of the
+                        * runlist.
+                        */
+                       down_write(&vol->lcnbmp_lock);
+                       if (ntfs_bitmap_clear_bit(vol->lcnbmp_ino, lcn)) {
+                               ntfs_error(vol->sb, "Failed to release "
+                                               "allocated cluster in error "
+                                               "code path.  Run chkdsk to "
+                                               "recover the lost cluster.");
+                               NVolSetErrors(vol);
+                       }
+                       up_write(&vol->lcnbmp_lock);
+               }
+       }
+       /*
+        * Resize the attribute record to its old size and rebuild the mapping
+        * pairs array.  Note, we only can do this if the runlist has been
+        * restored to its old state which also implies that the mapped
+        * attribute extent is not switched.
+        */
+       if (status.mp_rebuilt && !status.runlist_merged) {
+               if (ntfs_attr_record_resize(m, a, attr_rec_len)) {
+                       ntfs_error(vol->sb, "Failed to restore attribute "
+                                       "record in error code path.  Run "
+                                       "chkdsk to recover.");
+                       make_bad_inode(vi);
+                       make_bad_inode(VFS_I(base_ni));
+                       NVolSetErrors(vol);
+               } else /* if (success) */ {
+                       if (ntfs_mapping_pairs_build(vol, (u8*)a +
+                                       le16_to_cpu(a->data.non_resident.
+                                       mapping_pairs_offset), attr_rec_len -
+                                       le16_to_cpu(a->data.non_resident.
+                                       mapping_pairs_offset), ni->runlist.rl,
+                                       vcn, highest_vcn, NULL)) {
+                               ntfs_error(vol->sb, "Failed to restore "
+                                               "mapping pairs array in error "
+                                               "code path.  Run chkdsk to "
+                                               "recover.");
+                               make_bad_inode(vi);
+                               make_bad_inode(VFS_I(base_ni));
+                               NVolSetErrors(vol);
+                       }
+                       flush_dcache_mft_record_page(ctx->ntfs_ino);
+                       mark_mft_record_dirty(ctx->ntfs_ino);
+               }
+       }
+       /* Release the mft record and the attribute. */
+       if (status.mft_attr_mapped) {
+               ntfs_attr_put_search_ctx(ctx);
+               unmap_mft_record(base_ni);
+       }
+       /* Release the runlist lock. */
+       if (rl_write_locked)
+               up_write(&ni->runlist.lock);
+       else if (rl)
+               up_read(&ni->runlist.lock);
+       /*
+        * Zero out any newly allocated blocks to avoid exposing stale data.
+        * If BH_New is set, we know that the block was newly allocated above
+        * and that it has not been fully zeroed and marked dirty yet.
+        */
+       nr_pages = u;
+       u = 0;
+       end = bh_cpos << vol->cluster_size_bits;
+       do {
+               page = pages[u];
+               bh = head = page_buffers(page);
+               do {
+                       if (u == nr_pages &&
+                                       ((s64)page->index << PAGE_CACHE_SHIFT) +
+                                       bh_offset(bh) >= end)
+                               break;
+                       if (!buffer_new(bh))
+                               continue;
+                       clear_buffer_new(bh);
+                       if (!buffer_uptodate(bh)) {
+                               if (PageUptodate(page))
+                                       set_buffer_uptodate(bh);
+                               else {
+                                       u8 *kaddr = kmap_atomic(page, KM_USER0);
+                                       memset(kaddr + bh_offset(bh), 0,
+                                                       blocksize);
+                                       kunmap_atomic(kaddr, KM_USER0);
+                                       flush_dcache_page(page);
+                                       set_buffer_uptodate(bh);
+                               }
+                       }
+                       mark_buffer_dirty(bh);
+               } while ((bh = bh->b_this_page) != head);
+       } while (++u <= nr_pages);
+       ntfs_error(vol->sb, "Failed.  Returning error code %i.", err);
+       return err;
+}
+
+/*
+ * Copy as much as we can into the pages and return the number of bytes which
+ * were sucessfully copied.  If a fault is encountered then clear the pages
+ * out to (ofs + bytes) and return the number of bytes which were copied.
+ */
+static inline size_t ntfs_copy_from_user(struct page **pages,
+               unsigned nr_pages, unsigned ofs, const char __user *buf,
+               size_t bytes)
+{
+       struct page **last_page = pages + nr_pages;
+       char *kaddr;
+       size_t total = 0;
+       unsigned len;
+       int left;
+
+       do {
+               len = PAGE_CACHE_SIZE - ofs;
+               if (len > bytes)
+                       len = bytes;
+               kaddr = kmap_atomic(*pages, KM_USER0);
+               left = __copy_from_user_inatomic(kaddr + ofs, buf, len);
+               kunmap_atomic(kaddr, KM_USER0);
+               if (unlikely(left)) {
+                       /* Do it the slow way. */
+                       kaddr = kmap(*pages);
+                       left = __copy_from_user(kaddr + ofs, buf, len);
+                       kunmap(*pages);
+                       if (unlikely(left))
+                               goto err_out;
+               }
+               total += len;
+               bytes -= len;
+               if (!bytes)
+                       break;
+               buf += len;
+               ofs = 0;
+       } while (++pages < last_page);
+out:
+       return total;
+err_out:
+       total += len - left;
+       /* Zero the rest of the target like __copy_from_user(). */
+       while (++pages < last_page) {
+               bytes -= len;
+               if (!bytes)
+                       break;
+               len = PAGE_CACHE_SIZE;
+               if (len > bytes)
+                       len = bytes;
+               kaddr = kmap_atomic(*pages, KM_USER0);
+               memset(kaddr, 0, len);
+               kunmap_atomic(kaddr, KM_USER0);
+       }
+       goto out;
+}
+
+static size_t __ntfs_copy_from_user_iovec(char *vaddr,
+               const struct iovec *iov, size_t iov_ofs, size_t bytes)
+{
+       size_t total = 0;
+
+       while (1) {
+               const char __user *buf = iov->iov_base + iov_ofs;
+               unsigned len;
+               size_t left;
+
+               len = iov->iov_len - iov_ofs;
+               if (len > bytes)
+                       len = bytes;
+               left = __copy_from_user_inatomic(vaddr, buf, len);
+               total += len;
+               bytes -= len;
+               vaddr += len;
+               if (unlikely(left)) {
+                       /*
+                        * Zero the rest of the target like __copy_from_user().
+                        */
+                       memset(vaddr, 0, bytes);
+                       total -= left;
+                       break;
+               }
+               if (!bytes)
+                       break;
+               iov++;
+               iov_ofs = 0;
+       }
+       return total;
+}
+
+static inline void ntfs_set_next_iovec(const struct iovec **iovp,
+               size_t *iov_ofsp, size_t bytes)
+{
+       const struct iovec *iov = *iovp;
+       size_t iov_ofs = *iov_ofsp;
+
+       while (bytes) {
+               unsigned len;
+
+               len = iov->iov_len - iov_ofs;
+               if (len > bytes)
+                       len = bytes;
+               bytes -= len;
+               iov_ofs += len;
+               if (iov->iov_len == iov_ofs) {
+                       iov++;
+                       iov_ofs = 0;
+               }
+       }
+       *iovp = iov;
+       *iov_ofsp = iov_ofs;
+}
+
+/*
+ * This has the same side-effects and return value as ntfs_copy_from_user().
+ * The difference is that on a fault we need to memset the remainder of the
+ * pages (out to offset + bytes), to emulate ntfs_copy_from_user()'s
+ * single-segment behaviour.
+ *
+ * We call the same helper (__ntfs_copy_from_user_iovec()) both when atomic and
+ * when not atomic.  This is ok because __ntfs_copy_from_user_iovec() calls
+ * __copy_from_user_inatomic() and it is ok to call this when non-atomic.  In
+ * fact, the only difference between __copy_from_user_inatomic() and
+ * __copy_from_user() is that the latter calls might_sleep().  And on many
+ * architectures __copy_from_user_inatomic() is just defined to
+ * __copy_from_user() so it makes no difference at all on those architectures.
+ */
+static inline size_t ntfs_copy_from_user_iovec(struct page **pages,
+               unsigned nr_pages, unsigned ofs, const struct iovec **iov,
+               size_t *iov_ofs, size_t bytes)
+{
+       struct page **last_page = pages + nr_pages;
+       char *kaddr;
+       size_t copied, len, total = 0;
+
+       do {
+               len = PAGE_CACHE_SIZE - ofs;
+               if (len > bytes)
+                       len = bytes;
+               kaddr = kmap_atomic(*pages, KM_USER0);
+               copied = __ntfs_copy_from_user_iovec(kaddr + ofs,
+                               *iov, *iov_ofs, len);
+               kunmap_atomic(kaddr, KM_USER0);
+               if (unlikely(copied != len)) {
+                       /* Do it the slow way. */
+                       kaddr = kmap(*pages);
+                       copied = __ntfs_copy_from_user_iovec(kaddr + ofs,
+                                       *iov, *iov_ofs, len);
+                       kunmap(*pages);
+                       if (unlikely(copied != len))
+                               goto err_out;
+               }
+               total += len;
+               bytes -= len;
+               if (!bytes)
+                       break;
+               ntfs_set_next_iovec(iov, iov_ofs, len);
+               ofs = 0;
+       } while (++pages < last_page);
+out:
+       return total;
+err_out:
+       total += copied;
+       /* Zero the rest of the target like __copy_from_user(). */
+       while (++pages < last_page) {
+               bytes -= len;
+               if (!bytes)
+                       break;
+               len = PAGE_CACHE_SIZE;
+               if (len > bytes)
+                       len = bytes;
+               kaddr = kmap_atomic(*pages, KM_USER0);
+               memset(kaddr, 0, len);
+               kunmap_atomic(kaddr, KM_USER0);
+       }
+       goto out;
+}
+
+static inline void ntfs_flush_dcache_pages(struct page **pages,
+               unsigned nr_pages)
+{
+       BUG_ON(!nr_pages);
+       do {
+               /*
+                * Warning: Do not do the decrement at the same time as the
+                * call because flush_dcache_page() is a NULL macro on i386
+                * and hence the decrement never happens.
+                */
+               flush_dcache_page(pages[nr_pages]);
+       } while (--nr_pages > 0);
+}
+
+/**
+ * ntfs_commit_pages_after_non_resident_write - commit the received data
+ * @pages:     array of destination pages
+ * @nr_pages:  number of pages in @pages
+ * @pos:       byte position in file at which the write begins
+ * @bytes:     number of bytes to be written
+ *
+ * See description of ntfs_commit_pages_after_write(), below.
+ */
+static inline int ntfs_commit_pages_after_non_resident_write(
+               struct page **pages, const unsigned nr_pages,
+               s64 pos, size_t bytes)
+{
+       s64 end, initialized_size;
+       struct inode *vi;
+       ntfs_inode *ni, *base_ni;
+       struct buffer_head *bh, *head;
+       ntfs_attr_search_ctx *ctx;
+       MFT_RECORD *m;
+       ATTR_RECORD *a;
+       unsigned long flags;
+       unsigned blocksize, u;
+       int err;
+
+       vi = pages[0]->mapping->host;
+       ni = NTFS_I(vi);
+       blocksize = 1 << vi->i_blkbits;
+       end = pos + bytes;
+       u = 0;
+       do {
+               s64 bh_pos;
+               struct page *page;
+               BOOL partial;
+
+               page = pages[u];
+               bh_pos = (s64)page->index << PAGE_CACHE_SHIFT;
+               bh = head = page_buffers(page);
+               partial = FALSE;
+               do {
+                       s64 bh_end;
+
+                       bh_end = bh_pos + blocksize;
+                       if (bh_end <= pos || bh_pos >= end) {
+                               if (!buffer_uptodate(bh))
+                                       partial = TRUE;
+                       } else {
+                               set_buffer_uptodate(bh);
+                               mark_buffer_dirty(bh);
+                       }
+               } while (bh_pos += blocksize, (bh = bh->b_this_page) != head);
+               /*
+                * If all buffers are now uptodate but the page is not, set the
+                * page uptodate.
+                */
+               if (!partial && !PageUptodate(page))
+                       SetPageUptodate(page);
+       } while (++u < nr_pages);
+       /*
+        * Finally, if we do not need to update initialized_size or i_size we
+        * are finished.
+        */
+       read_lock_irqsave(&ni->size_lock, flags);
+       initialized_size = ni->initialized_size;
+       read_unlock_irqrestore(&ni->size_lock, flags);
+       if (end <= initialized_size) {
+               ntfs_debug("Done.");
+               return 0;
+       }
+       /*
+        * Update initialized_size/i_size as appropriate, both in the inode and
+        * the mft record.
+        */
+       if (!NInoAttr(ni))
+               base_ni = ni;
+       else
+               base_ni = ni->ext.base_ntfs_ino;
+       /* Map, pin, and lock the mft record. */
+       m = map_mft_record(base_ni);
+       if (IS_ERR(m)) {
+               err = PTR_ERR(m);
+               m = NULL;
+               ctx = NULL;
+               goto err_out;
+       }
+       BUG_ON(!NInoNonResident(ni));
+       ctx = ntfs_attr_get_search_ctx(base_ni, m);
+       if (unlikely(!ctx)) {
+               err = -ENOMEM;
+               goto err_out;
+       }
+       err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+                       CASE_SENSITIVE, 0, NULL, 0, ctx);
+       if (unlikely(err)) {
+               if (err == -ENOENT)
+                       err = -EIO;
+               goto err_out;
+       }
+       a = ctx->attr;
+       BUG_ON(!a->non_resident);
+       write_lock_irqsave(&ni->size_lock, flags);
+       BUG_ON(end > ni->allocated_size);
+       ni->initialized_size = end;
+       a->data.non_resident.initialized_size = cpu_to_sle64(end);
+       if (end > i_size_read(vi)) {
+               i_size_write(vi, end);
+               a->data.non_resident.data_size =
+                               a->data.non_resident.initialized_size;
+       }
+       write_unlock_irqrestore(&ni->size_lock, flags);
+       /* Mark the mft record dirty, so it gets written back. */
+       flush_dcache_mft_record_page(ctx->ntfs_ino);
+       mark_mft_record_dirty(ctx->ntfs_ino);
+       ntfs_attr_put_search_ctx(ctx);
+       unmap_mft_record(base_ni);
+       ntfs_debug("Done.");
+       return 0;
+err_out:
+       if (ctx)
+               ntfs_attr_put_search_ctx(ctx);
+       if (m)
+               unmap_mft_record(base_ni);
+       ntfs_error(vi->i_sb, "Failed to update initialized_size/i_size (error "
+                       "code %i).", err);
+       if (err != -ENOMEM) {
+               NVolSetErrors(ni->vol);
+               make_bad_inode(VFS_I(base_ni));
+               make_bad_inode(vi);
+       }
+       return err;
+}
+
+/**
+ * ntfs_commit_pages_after_write - commit the received data
+ * @pages:     array of destination pages
+ * @nr_pages:  number of pages in @pages
+ * @pos:       byte position in file at which the write begins
+ * @bytes:     number of bytes to be written
+ *
+ * This is called from ntfs_file_buffered_write() with i_sem held on the inode
+ * (@pages[0]->mapping->host).  There are @nr_pages pages in @pages which are
+ * locked but not kmap()ped.  The source data has already been copied into the
+ * @page.  ntfs_prepare_pages_for_non_resident_write() has been called before
+ * the data was copied (for non-resident attributes only) and it returned
+ * success.
+ *
+ * Need to set uptodate and mark dirty all buffers within the boundary of the
+ * write.  If all buffers in a page are uptodate we set the page uptodate, too.
+ *
+ * Setting the buffers dirty ensures that they get written out later when
+ * ntfs_writepage() is invoked by the VM.
+ *
+ * Finally, we need to update i_size and initialized_size as appropriate both
+ * in the inode and the mft record.
+ *
+ * This is modelled after fs/buffer.c::generic_commit_write(), which marks
+ * buffers uptodate and dirty, sets the page uptodate if all buffers in the
+ * page are uptodate, and updates i_size if the end of io is beyond i_size.  In
+ * that case, it also marks the inode dirty.
+ *
+ * If things have gone as outlined in
+ * ntfs_prepare_pages_for_non_resident_write(), we do not need to do any page
+ * content modifications here for non-resident attributes.  For resident
+ * attributes we need to do the uptodate bringing here which we combine with
+ * the copying into the mft record which means we save one atomic kmap.
+ *
+ * Return 0 on success or -errno on error.
+ */
+static int ntfs_commit_pages_after_write(struct page **pages,
+               const unsigned nr_pages, s64 pos, size_t bytes)
+{
+       s64 end, initialized_size;
+       loff_t i_size;
+       struct inode *vi;
+       ntfs_inode *ni, *base_ni;
+       struct page *page;
+       ntfs_attr_search_ctx *ctx;
+       MFT_RECORD *m;
+       ATTR_RECORD *a;
+       char *kattr, *kaddr;
+       unsigned long flags;
+       u32 attr_len;
+       int err;
+
+       BUG_ON(!nr_pages);
+       BUG_ON(!pages);
+       page = pages[0];
+       BUG_ON(!page);
+       vi = page->mapping->host;
+       ni = NTFS_I(vi);
+       ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, start page "
+                       "index 0x%lx, nr_pages 0x%x, pos 0x%llx, bytes 0x%x.",
+                       vi->i_ino, ni->type, page->index, nr_pages,
+                       (long long)pos, bytes);
+       if (NInoNonResident(ni))
+               return ntfs_commit_pages_after_non_resident_write(pages,
+                               nr_pages, pos, bytes);
+       BUG_ON(nr_pages > 1);
+       /*
+        * Attribute is resident, implying it is not compressed, encrypted, or
+        * sparse.
+        */
+       if (!NInoAttr(ni))
+               base_ni = ni;
+       else
+               base_ni = ni->ext.base_ntfs_ino;
+       BUG_ON(NInoNonResident(ni));
+       /* Map, pin, and lock the mft record. */
+       m = map_mft_record(base_ni);
+       if (IS_ERR(m)) {
+               err = PTR_ERR(m);
+               m = NULL;
+               ctx = NULL;
+               goto err_out;
+       }
+       ctx = ntfs_attr_get_search_ctx(base_ni, m);
+       if (unlikely(!ctx)) {
+               err = -ENOMEM;
+               goto err_out;
+       }
+       err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+                       CASE_SENSITIVE, 0, NULL, 0, ctx);
+       if (unlikely(err)) {
+               if (err == -ENOENT)
+                       err = -EIO;
+               goto err_out;
+       }
+       a = ctx->attr;
+       BUG_ON(a->non_resident);
+       /* The total length of the attribute value. */
+       attr_len = le32_to_cpu(a->data.resident.value_length);
+       i_size = i_size_read(vi);
+       BUG_ON(attr_len != i_size);
+       BUG_ON(pos > attr_len);
+       end = pos + bytes;
+       BUG_ON(end > le32_to_cpu(a->length) -
+                       le16_to_cpu(a->data.resident.value_offset));
+       kattr = (u8*)a + le16_to_cpu(a->data.resident.value_offset);
+       kaddr = kmap_atomic(page, KM_USER0);
+       /* Copy the received data from the page to the mft record. */
+       memcpy(kattr + pos, kaddr + pos, bytes);
+       /* Update the attribute length if necessary. */
+       if (end > attr_len) {
+               attr_len = end;
+               a->data.resident.value_length = cpu_to_le32(attr_len);
+       }
+       /*
+        * If the page is not uptodate, bring the out of bounds area(s)
+        * uptodate by copying data from the mft record to the page.
+        */
+       if (!PageUptodate(page)) {
+               if (pos > 0)
+                       memcpy(kaddr, kattr, pos);
+               if (end < attr_len)
+                       memcpy(kaddr + end, kattr + end, attr_len - end);
+               /* Zero the region outside the end of the attribute value. */
+               memset(kaddr + attr_len, 0, PAGE_CACHE_SIZE - attr_len);
+               flush_dcache_page(page);
+               SetPageUptodate(page);
+       }
+       kunmap_atomic(kaddr, KM_USER0);
+       /* Update initialized_size/i_size if necessary. */
+       read_lock_irqsave(&ni->size_lock, flags);
+       initialized_size = ni->initialized_size;
+       BUG_ON(end > ni->allocated_size);
+       read_unlock_irqrestore(&ni->size_lock, flags);
+       BUG_ON(initialized_size != i_size);
+       if (end > initialized_size) {
+               unsigned long flags;
+
+               write_lock_irqsave(&ni->size_lock, flags);
+               ni->initialized_size = end;
+               i_size_write(vi, end);
+               write_unlock_irqrestore(&ni->size_lock, flags);
+       }
+       /* Mark the mft record dirty, so it gets written back. */
+       flush_dcache_mft_record_page(ctx->ntfs_ino);
+       mark_mft_record_dirty(ctx->ntfs_ino);
+       ntfs_attr_put_search_ctx(ctx);
+       unmap_mft_record(base_ni);
+       ntfs_debug("Done.");
+       return 0;
+err_out:
+       if (err == -ENOMEM) {
+               ntfs_warning(vi->i_sb, "Error allocating memory required to "
+                               "commit the write.");
+               if (PageUptodate(page)) {
+                       ntfs_warning(vi->i_sb, "Page is uptodate, setting "
+                                       "dirty so the write will be retried "
+                                       "later on by the VM.");
+                       /*
+                        * Put the page on mapping->dirty_pages, but leave its
+                        * buffers' dirty state as-is.
+                        */
+                       __set_page_dirty_nobuffers(page);
+                       err = 0;
+               } else
+                       ntfs_error(vi->i_sb, "Page is not uptodate.  Written "
+                                       "data has been lost.");
+       } else {
+               ntfs_error(vi->i_sb, "Resident attribute commit write failed "
+                               "with error %i.", err);
+               NVolSetErrors(ni->vol);
+               make_bad_inode(VFS_I(base_ni));
+               make_bad_inode(vi);
+       }
+       if (ctx)
+               ntfs_attr_put_search_ctx(ctx);
+       if (m)
+               unmap_mft_record(base_ni);
+       return err;
+}
+
+/**
+ * ntfs_file_buffered_write -
+ *
+ * Locking: The vfs is holding ->i_sem on the inode.
+ */
+static ssize_t ntfs_file_buffered_write(struct kiocb *iocb,
+               const struct iovec *iov, unsigned long nr_segs,
+               loff_t pos, loff_t *ppos, size_t count)
+{
+       struct file *file = iocb->ki_filp;
+       struct address_space *mapping = file->f_mapping;
+       struct inode *vi = mapping->host;
+       ntfs_inode *ni = NTFS_I(vi);
+       ntfs_volume *vol = ni->vol;
+       struct page *pages[NTFS_MAX_PAGES_PER_CLUSTER];
+       struct page *cached_page = NULL;
+       char __user *buf = NULL;
+       s64 end, ll;
+       VCN last_vcn;
+       LCN lcn;
+       unsigned long flags;
+       size_t bytes, iov_ofs;
+       ssize_t status, written;
+       unsigned nr_pages;
+       int err;
+       struct pagevec lru_pvec;
+
+       ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, "
+                       "pos 0x%llx, count 0x%lx.",
+                       vi->i_ino, (unsigned)le32_to_cpu(ni->type),
+                       (unsigned long long)pos, (unsigned long)count);
+       if (unlikely(!count))
+               return 0;
+       BUG_ON(NInoMstProtected(ni));
+       /*
+        * If the attribute is not an index root and it is encrypted or
+        * compressed, we cannot write to it yet.  Note we need to check for
+        * AT_INDEX_ALLOCATION since this is the type of both directory and
+        * index inodes.
+        */
+       if (ni->type != AT_INDEX_ALLOCATION) {
+               /* If file is encrypted, deny access, just like NT4. */
+               if (NInoEncrypted(ni)) {
+                       ntfs_debug("Denying write access to encrypted file.");
+                       return -EACCES;
+               }
+               if (NInoCompressed(ni)) {
+                       ntfs_error(vi->i_sb, "Writing to compressed files is "
+                                       "not implemented yet.  Sorry.");
+                       return -EOPNOTSUPP;
+               }
+       }
+       /*
+        * If a previous ntfs_truncate() failed, repeat it and abort if it
+        * fails again.
+        */
+       if (unlikely(NInoTruncateFailed(ni))) {
+               down_write(&vi->i_alloc_sem);
+               err = ntfs_truncate(vi);
+               up_write(&vi->i_alloc_sem);
+               if (err || NInoTruncateFailed(ni)) {
+                       if (!err)
+                               err = -EIO;
+                       ntfs_error(vol->sb, "Cannot perform write to inode "
+                                       "0x%lx, attribute type 0x%x, because "
+                                       "ntfs_truncate() failed (error code "
+                                       "%i).", vi->i_ino,
+                                       (unsigned)le32_to_cpu(ni->type), err);
+                       return err;
+               }
+       }
+       /* The first byte after the write. */
+       end = pos + count;
+       /*
+        * If the write goes beyond the allocated size, extend the allocation
+        * to cover the whole of the write, rounded up to the nearest cluster.
+        */
+       read_lock_irqsave(&ni->size_lock, flags);
+       ll = ni->allocated_size;
+       read_unlock_irqrestore(&ni->size_lock, flags);
+       if (end > ll) {
+               /* Extend the allocation without changing the data size. */
+               ll = ntfs_attr_extend_allocation(ni, end, -1, pos);
+               if (likely(ll >= 0)) {
+                       BUG_ON(pos >= ll);
+                       /* If the extension was partial truncate the write. */
+                       if (end > ll) {
+                               ntfs_debug("Truncating write to inode 0x%lx, "
+                                               "attribute type 0x%x, because "
+                                               "the allocation was only "
+                                               "partially extended.",
+                                               vi->i_ino, (unsigned)
+                                               le32_to_cpu(ni->type));
+                               end = ll;
+                               count = ll - pos;
+                       }
+               } else {
+                       err = ll;
+                       read_lock_irqsave(&ni->size_lock, flags);
+                       ll = ni->allocated_size;
+                       read_unlock_irqrestore(&ni->size_lock, flags);
+                       /* Perform a partial write if possible or fail. */
+                       if (pos < ll) {
+                               ntfs_debug("Truncating write to inode 0x%lx, "
+                                               "attribute type 0x%x, because "
+                                               "extending the allocation "
+                                               "failed (error code %i).",
+                                               vi->i_ino, (unsigned)
+                                               le32_to_cpu(ni->type), err);
+                               end = ll;
+                               count = ll - pos;
+                       } else {
+                               ntfs_error(vol->sb, "Cannot perform write to "
+                                               "inode 0x%lx, attribute type "
+                                               "0x%x, because extending the "
+                                               "allocation failed (error "
+                                               "code %i).", vi->i_ino,
+                                               (unsigned)
+                                               le32_to_cpu(ni->type), err);
+                               return err;
+                       }
+               }
+       }
+       pagevec_init(&lru_pvec, 0);
+       written = 0;
+       /*
+        * If the write starts beyond the initialized size, extend it up to the
+        * beginning of the write and initialize all non-sparse space between
+        * the old initialized size and the new one.  This automatically also
+        * increments the vfs inode->i_size to keep it above or equal to the
+        * initialized_size.
+        */
+       read_lock_irqsave(&ni->size_lock, flags);
+       ll = ni->initialized_size;
+       read_unlock_irqrestore(&ni->size_lock, flags);
+       if (pos > ll) {
+               err = ntfs_attr_extend_initialized(ni, pos, &cached_page,
+                               &lru_pvec);
+               if (err < 0) {
+                       ntfs_error(vol->sb, "Cannot perform write to inode "
+                                       "0x%lx, attribute type 0x%x, because "
+                                       "extending the initialized size "
+                                       "failed (error code %i).", vi->i_ino,
+                                       (unsigned)le32_to_cpu(ni->type), err);
+                       status = err;
+                       goto err_out;
+               }
+       }
+       /*
+        * Determine the number of pages per cluster for non-resident
+        * attributes.
+        */
+       nr_pages = 1;
+       if (vol->cluster_size > PAGE_CACHE_SIZE && NInoNonResident(ni))
+               nr_pages = vol->cluster_size >> PAGE_CACHE_SHIFT;
+       /* Finally, perform the actual write. */
+       last_vcn = -1;
+       if (likely(nr_segs == 1))
+               buf = iov->iov_base;
+       else
+               iov_ofs = 0;    /* Offset in the current iovec. */
+       do {
+               VCN vcn;
+               pgoff_t idx, start_idx;
+               unsigned ofs, do_pages, u;
+               size_t copied;
+
+               start_idx = idx = pos >> PAGE_CACHE_SHIFT;
+               ofs = pos & ~PAGE_CACHE_MASK;
+               bytes = PAGE_CACHE_SIZE - ofs;
+               do_pages = 1;
+               if (nr_pages > 1) {
+                       vcn = pos >> vol->cluster_size_bits;
+                       if (vcn != last_vcn) {
+                               last_vcn = vcn;
+                               /*
+                                * Get the lcn of the vcn the write is in.  If
+                                * it is a hole, need to lock down all pages in
+                                * the cluster.
+                                */
+                               down_read(&ni->runlist.lock);
+                               lcn = ntfs_attr_vcn_to_lcn_nolock(ni, pos >>
+                                               vol->cluster_size_bits, FALSE);
+                               up_read(&ni->runlist.lock);
+                               if (unlikely(lcn < LCN_HOLE)) {
+                                       status = -EIO;
+                                       if (lcn == LCN_ENOMEM)
+                                               status = -ENOMEM;
+                                       else
+                                               ntfs_error(vol->sb, "Cannot "
+                                                       "perform write to "
+                                                       "inode 0x%lx, "
+                                                       "attribute type 0x%x, "
+                                                       "because the attribute "
+                                                       "is corrupt.",
+                                                       vi->i_ino, (unsigned)
+                                                       le32_to_cpu(ni->type));
+                                       break;
+                               }
+                               if (lcn == LCN_HOLE) {
+                                       start_idx = (pos & ~(s64)
+                                                       vol->cluster_size_mask)
+                                                       >> PAGE_CACHE_SHIFT;
+                                       bytes = vol->cluster_size - (pos &
+                                                       vol->cluster_size_mask);
+                                       do_pages = nr_pages;
+                               }
+                       }
+               }
+               if (bytes > count)
+                       bytes = count;
+               /*
+                * Bring in the user page(s) that we will copy from _first_.
+                * Otherwise there is a nasty deadlock on copying from the same
+                * page(s) as we are writing to, without it/them being marked
+                * up-to-date.  Note, at present there is nothing to stop the
+                * pages being swapped out between us bringing them into memory
+                * and doing the actual copying.
+                */
+               if (likely(nr_segs == 1))
+                       ntfs_fault_in_pages_readable(buf, bytes);
+               else
+                       ntfs_fault_in_pages_readable_iovec(iov, iov_ofs, bytes);
+               /* Get and lock @do_pages starting at index @start_idx. */
+               status = __ntfs_grab_cache_pages(mapping, start_idx, do_pages,
+                               pages, &cached_page, &lru_pvec);
+               if (unlikely(status))
+                       break;
+               /*
+                * For non-resident attributes, we need to fill any holes with
+                * actual clusters and ensure all bufferes are mapped.  We also
+                * need to bring uptodate any buffers that are only partially
+                * being written to.
+                */
+               if (NInoNonResident(ni)) {
+                       status = ntfs_prepare_pages_for_non_resident_write(
+                                       pages, do_pages, pos, bytes);
+                       if (unlikely(status)) {
+                               loff_t i_size;
+
+                               do {
+                                       unlock_page(pages[--do_pages]);
+                                       page_cache_release(pages[do_pages]);
+                               } while (do_pages);
+                               /*
+                                * The write preparation may have instantiated
+                                * allocated space outside i_size.  Trim this
+                                * off again.  We can ignore any errors in this
+                                * case as we will just be waisting a bit of
+                                * allocated space, which is not a disaster.
+                                */
+                               i_size = i_size_read(vi);
+                               if (pos + bytes > i_size)
+                                       vmtruncate(vi, i_size);
+                               break;
+                       }
+               }
+               u = (pos >> PAGE_CACHE_SHIFT) - pages[0]->index;
+               if (likely(nr_segs == 1)) {
+                       copied = ntfs_copy_from_user(pages + u, do_pages - u,
+                                       ofs, buf, bytes);
+                       buf += copied;
+               } else
+                       copied = ntfs_copy_from_user_iovec(pages + u,
+                                       do_pages - u, ofs, &iov, &iov_ofs,
+                                       bytes);
+               ntfs_flush_dcache_pages(pages + u, do_pages - u);
+               status = ntfs_commit_pages_after_write(pages, do_pages, pos,
+                               bytes);
+               if (likely(!status)) {
+                       written += copied;
+                       count -= copied;
+                       pos += copied;
+                       if (unlikely(copied != bytes))
+                               status = -EFAULT;
+               }
+               do {
+                       unlock_page(pages[--do_pages]);
+                       mark_page_accessed(pages[do_pages]);
+                       page_cache_release(pages[do_pages]);
+               } while (do_pages);
+               if (unlikely(status))
+                       break;
+               balance_dirty_pages_ratelimited(mapping);
+               cond_resched();
+       } while (count);
+err_out:
+       *ppos = pos;
+       if (cached_page)
+               page_cache_release(cached_page);
+       /* For now, when the user asks for O_SYNC, we actually give O_DSYNC. */
+       if (likely(!status)) {
+               if (unlikely((file->f_flags & O_SYNC) || IS_SYNC(vi))) {
+                       if (!mapping->a_ops->writepage || !is_sync_kiocb(iocb))
+                               status = generic_osync_inode(vi, mapping,
+                                               OSYNC_METADATA|OSYNC_DATA);
+               }
+       }
+       pagevec_lru_add(&lru_pvec);
+       ntfs_debug("Done.  Returning %s (written 0x%lx, status %li).",
+                       written ? "written" : "status", (unsigned long)written,
+                       (long)status);
+       return written ? written : status;
+}
+
+/**
+ * ntfs_file_aio_write_nolock -
+ */
+static ssize_t ntfs_file_aio_write_nolock(struct kiocb *iocb,
+               const struct iovec *iov, unsigned long nr_segs, loff_t *ppos)
+{
+       struct file *file = iocb->ki_filp;
+       struct address_space *mapping = file->f_mapping;
+       struct inode *inode = mapping->host;
+       loff_t pos;
+       unsigned long seg;
+       size_t count;           /* after file limit checks */
+       ssize_t written, err;
+
+       count = 0;
+       for (seg = 0; seg < nr_segs; seg++) {
+               const struct iovec *iv = &iov[seg];
+               /*
+                * If any segment has a negative length, or the cumulative
+                * length ever wraps negative then return -EINVAL.
+                */
+               count += iv->iov_len;
+               if (unlikely((ssize_t)(count|iv->iov_len) < 0))
+                       return -EINVAL;
+               if (access_ok(VERIFY_READ, iv->iov_base, iv->iov_len))
+                       continue;
+               if (!seg)
+                       return -EFAULT;
+               nr_segs = seg;
+               count -= iv->iov_len;   /* This segment is no good */
+               break;
+       }
+       pos = *ppos;
+       vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+       /* We can write back this queue in page reclaim. */
+       current->backing_dev_info = mapping->backing_dev_info;
+       written = 0;
+       err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
+       if (err)
+               goto out;
+       if (!count)
+               goto out;
+       err = remove_suid(file->f_dentry);
+       if (err)
+               goto out;
+       inode_update_time(inode, 1);
+       written = ntfs_file_buffered_write(iocb, iov, nr_segs, pos, ppos,
+                       count);
+out:
+       current->backing_dev_info = NULL;
+       return written ? written : err;
+}
+
+/**
+ * ntfs_file_aio_write -
+ */
+static ssize_t ntfs_file_aio_write(struct kiocb *iocb, const char __user *buf,
+               size_t count, loff_t pos)
+{
+       struct file *file = iocb->ki_filp;
+       struct address_space *mapping = file->f_mapping;
+       struct inode *inode = mapping->host;
+       ssize_t ret;
+       struct iovec local_iov = { .iov_base = (void __user *)buf,
+                                  .iov_len = count };
+
+       BUG_ON(iocb->ki_pos != pos);
+
+       down(&inode->i_sem);
+       ret = ntfs_file_aio_write_nolock(iocb, &local_iov, 1, &iocb->ki_pos);
+       up(&inode->i_sem);
+       if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
+               int err = sync_page_range(inode, mapping, pos, ret);
+               if (err < 0)
+                       ret = err;
+       }
+       return ret;
+}
+
+/**
+ * ntfs_file_writev -
+ *
+ * Basically the same as generic_file_writev() except that it ends up calling
+ * ntfs_file_aio_write_nolock() instead of __generic_file_aio_write_nolock().
+ */
+static ssize_t ntfs_file_writev(struct file *file, const struct iovec *iov,
+               unsigned long nr_segs, loff_t *ppos)
+{
+       struct address_space *mapping = file->f_mapping;
+       struct inode *inode = mapping->host;
+       struct kiocb kiocb;
+       ssize_t ret;
+
+       down(&inode->i_sem);
+       init_sync_kiocb(&kiocb, file);
+       ret = ntfs_file_aio_write_nolock(&kiocb, iov, nr_segs, ppos);
+       if (ret == -EIOCBQUEUED)
+               ret = wait_on_sync_kiocb(&kiocb);
+       up(&inode->i_sem);
+       if (ret > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
+               int err = sync_page_range(inode, mapping, *ppos - ret, ret);
+               if (err < 0)
+                       ret = err;
+       }
+       return ret;
+}
+
+/**
+ * ntfs_file_write - simple wrapper for ntfs_file_writev()
+ */
+static ssize_t ntfs_file_write(struct file *file, const char __user *buf,
+               size_t count, loff_t *ppos)
+{
+       struct iovec local_iov = { .iov_base = (void __user *)buf,
+                                  .iov_len = count };
+
+       return ntfs_file_writev(file, &local_iov, 1, ppos);
+}
+
 /**
  * ntfs_file_fsync - sync a file to disk
  * @filp:      file to be synced
@@ -113,39 +2296,39 @@ static int ntfs_file_fsync(struct file *filp, struct dentry *dentry,
 #endif /* NTFS_RW */
 
 struct file_operations ntfs_file_ops = {
-       .llseek         = generic_file_llseek,    /* Seek inside file. */
-       .read           = generic_file_read,      /* Read from file. */
-       .aio_read       = generic_file_aio_read,  /* Async read from file. */
-       .readv          = generic_file_readv,     /* Read from file. */
+       .llseek         = generic_file_llseek,   /* Seek inside file. */
+       .read           = generic_file_read,     /* Read from file. */
+       .aio_read       = generic_file_aio_read, /* Async read from file. */
+       .readv          = generic_file_readv,    /* Read from file. */
 #ifdef NTFS_RW
-       .write          = generic_file_write,     /* Write to file. */
-       .aio_write      = generic_file_aio_write, /* Async write to file. */
-       .writev         = generic_file_writev,    /* Write to file. */
-       /*.release      = ,*/                     /* Last file is closed.  See
-                                                    fs/ext2/file.c::
-                                                    ext2_release_file() for
-                                                    how to use this to discard
-                                                    preallocated space for
-                                                    write opened files. */
-       .fsync          = ntfs_file_fsync,        /* Sync a file to disk. */
-       /*.aio_fsync    = ,*/                     /* Sync all outstanding async
-                                                    i/o operations on a
-                                                    kiocb. */
+       .write          = ntfs_file_write,       /* Write to file. */
+       .aio_write      = ntfs_file_aio_write,   /* Async write to file. */
+       .writev         = ntfs_file_writev,      /* Write to file. */
+       /*.release      = ,*/                    /* Last file is closed.  See
+                                                   fs/ext2/file.c::
+                                                   ext2_release_file() for
+                                                   how to use this to discard
+                                                   preallocated space for
+                                                   write opened files. */
+       .fsync          = ntfs_file_fsync,       /* Sync a file to disk. */
+       /*.aio_fsync    = ,*/                    /* Sync all outstanding async
+                                                   i/o operations on a
+                                                   kiocb. */
 #endif /* NTFS_RW */
-       /*.ioctl        = ,*/                     /* Perform function on the
-                                                    mounted filesystem. */
-       .mmap           = generic_file_mmap,      /* Mmap file. */
-       .open           = ntfs_file_open,         /* Open file. */
-       .sendfile       = generic_file_sendfile,  /* Zero-copy data send with
-                                                    the data source being on
-                                                    the ntfs partition.  We
-                                                    do not need to care about
-                                                    the data destination. */
-       /*.sendpage     = ,*/                     /* Zero-copy data send with
-                                                    the data destination being
-                                                    on the ntfs partition.  We
-                                                    do not need to care about
-                                                    the data source. */
+       /*.ioctl        = ,*/                    /* Perform function on the
+                                                   mounted filesystem. */
+       .mmap           = generic_file_mmap,     /* Mmap file. */
+       .open           = ntfs_file_open,        /* Open file. */
+       .sendfile       = generic_file_sendfile, /* Zero-copy data send with
+                                                   the data source being on
+                                                   the ntfs partition.  We do
+                                                   not need to care about the
+                                                   data destination. */
+       /*.sendpage     = ,*/                    /* Zero-copy data send with
+                                                   the data destination being
+                                                   on the ntfs partition.  We
+                                                   do not need to care about
+                                                   the data source. */
 };
 
 struct inode_operations ntfs_file_inode_ops = {
index 7ec045131808b14546333a16009746729a2d236d..b24f4c4b2c5ccff9e80a8018ceb56b296b7ae74c 100644 (file)
@@ -30,6 +30,7 @@
 #include "debug.h"
 #include "inode.h"
 #include "attrib.h"
+#include "lcnalloc.h"
 #include "malloc.h"
 #include "mft.h"
 #include "time.h"
@@ -2291,11 +2292,16 @@ int ntfs_show_options(struct seq_file *sf, struct vfsmount *mnt)
 
 #ifdef NTFS_RW
 
+static const char *es = "  Leaving inconsistent metadata.  Unmount and run "
+               "chkdsk.";
+
 /**
  * ntfs_truncate - called when the i_size of an ntfs inode is changed
  * @vi:                inode for which the i_size was changed
  *
- * We do not support i_size changes yet.
+ * We only support i_size changes for normal files at present, i.e. not
+ * compressed and not encrypted.  This is enforced in ntfs_setattr(), see
+ * below.
  *
  * The kernel guarantees that @vi is a regular file (S_ISREG() is true) and
  * that the change is allowed.
@@ -2306,80 +2312,499 @@ int ntfs_show_options(struct seq_file *sf, struct vfsmount *mnt)
  * Returns 0 on success or -errno on error.
  *
  * Called with ->i_sem held.  In all but one case ->i_alloc_sem is held for
- * writing.  The only case where ->i_alloc_sem is not held is
+ * writing.  The only case in the kernel where ->i_alloc_sem is not held is
  * mm/filemap.c::generic_file_buffered_write() where vmtruncate() is called
- * with the current i_size as the offset which means that it is a noop as far
- * as ntfs_truncate() is concerned.
+ * with the current i_size as the offset.  The analogous place in NTFS is in
+ * fs/ntfs/file.c::ntfs_file_buffered_write() where we call vmtruncate() again
+ * without holding ->i_alloc_sem.
  */
 int ntfs_truncate(struct inode *vi)
 {
-       ntfs_inode *ni = NTFS_I(vi);
+       s64 new_size, old_size, nr_freed, new_alloc_size, old_alloc_size;
+       VCN highest_vcn;
+       unsigned long flags;
+       ntfs_inode *base_ni, *ni = NTFS_I(vi);
        ntfs_volume *vol = ni->vol;
        ntfs_attr_search_ctx *ctx;
        MFT_RECORD *m;
        ATTR_RECORD *a;
        const char *te = "  Leaving file length out of sync with i_size.";
-       int err;
+       int err, mp_size, size_change, alloc_change;
+       u32 attr_len;
 
        ntfs_debug("Entering for inode 0x%lx.", vi->i_ino);
        BUG_ON(NInoAttr(ni));
+       BUG_ON(S_ISDIR(vi->i_mode));
+       BUG_ON(NInoMstProtected(ni));
        BUG_ON(ni->nr_extents < 0);
-       m = map_mft_record(ni);
+retry_truncate:
+       /*
+        * Lock the runlist for writing and map the mft record to ensure it is
+        * safe to mess with the attribute runlist and sizes.
+        */
+       down_write(&ni->runlist.lock);
+       if (!NInoAttr(ni))
+               base_ni = ni;
+       else
+               base_ni = ni->ext.base_ntfs_ino;
+       m = map_mft_record(base_ni);
        if (IS_ERR(m)) {
                err = PTR_ERR(m);
                ntfs_error(vi->i_sb, "Failed to map mft record for inode 0x%lx "
                                "(error code %d).%s", vi->i_ino, err, te);
                ctx = NULL;
                m = NULL;
-               goto err_out;
+               goto old_bad_out;
        }
-       ctx = ntfs_attr_get_search_ctx(ni, m);
+       ctx = ntfs_attr_get_search_ctx(base_ni, m);
        if (unlikely(!ctx)) {
                ntfs_error(vi->i_sb, "Failed to allocate a search context for "
                                "inode 0x%lx (not enough memory).%s",
                                vi->i_ino, te);
                err = -ENOMEM;
-               goto err_out;
+               goto old_bad_out;
        }
        err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
                        CASE_SENSITIVE, 0, NULL, 0, ctx);
        if (unlikely(err)) {
-               if (err == -ENOENT)
+               if (err == -ENOENT) {
                        ntfs_error(vi->i_sb, "Open attribute is missing from "
                                        "mft record.  Inode 0x%lx is corrupt.  "
-                                       "Run chkdsk.", vi->i_ino);
-               else
+                                       "Run chkdsk.%s", vi->i_ino, te);
+                       err = -EIO;
+               } else
                        ntfs_error(vi->i_sb, "Failed to lookup attribute in "
-                                       "inode 0x%lx (error code %d).",
-                                       vi->i_ino, err);
-               goto err_out;
+                                       "inode 0x%lx (error code %d).%s",
+                                       vi->i_ino, err, te);
+               goto old_bad_out;
        }
+       m = ctx->mrec;
        a = ctx->attr;
-       /* If the size has not changed there is nothing to do. */
-       if (ntfs_attr_size(a) == i_size_read(vi))
-               goto done;
-       // TODO: Implement the truncate...
-       ntfs_error(vi->i_sb, "Inode size has changed but this is not "
-                       "implemented yet.  Resetting inode size to old value. "
-                       " This is most likely a bug in the ntfs driver!");
-       i_size_write(vi, ntfs_attr_size(a)); 
-done:
+       /*
+        * The i_size of the vfs inode is the new size for the attribute value.
+        */
+       new_size = i_size_read(vi);
+       /* The current size of the attribute value is the old size. */
+       old_size = ntfs_attr_size(a);
+       /* Calculate the new allocated size. */
+       if (NInoNonResident(ni))
+               new_alloc_size = (new_size + vol->cluster_size - 1) &
+                               ~(s64)vol->cluster_size_mask;
+       else
+               new_alloc_size = (new_size + 7) & ~7;
+       /* The current allocated size is the old allocated size. */
+       read_lock_irqsave(&ni->size_lock, flags);
+       old_alloc_size = ni->allocated_size;
+       read_unlock_irqrestore(&ni->size_lock, flags);
+       /*
+        * The change in the file size.  This will be 0 if no change, >0 if the
+        * size is growing, and <0 if the size is shrinking.
+        */
+       size_change = -1;
+       if (new_size - old_size >= 0) {
+               size_change = 1;
+               if (new_size == old_size)
+                       size_change = 0;
+       }
+       /* As above for the allocated size. */
+       alloc_change = -1;
+       if (new_alloc_size - old_alloc_size >= 0) {
+               alloc_change = 1;
+               if (new_alloc_size == old_alloc_size)
+                       alloc_change = 0;
+       }
+       /*
+        * If neither the size nor the allocation are being changed there is
+        * nothing to do.
+        */
+       if (!size_change && !alloc_change)
+               goto unm_done;
+       /* If the size is changing, check if new size is allowed in $AttrDef. */
+       if (size_change) {
+               err = ntfs_attr_size_bounds_check(vol, ni->type, new_size);
+               if (unlikely(err)) {
+                       if (err == -ERANGE) {
+                               ntfs_error(vol->sb, "Truncate would cause the "
+                                               "inode 0x%lx to %simum size "
+                                               "for its attribute type "
+                                               "(0x%x).  Aborting truncate.",
+                                               vi->i_ino,
+                                               new_size > old_size ? "exceed "
+                                               "the max" : "go under the min",
+                                               le32_to_cpu(ni->type));
+                               err = -EFBIG;
+                       } else {
+                               ntfs_error(vol->sb, "Inode 0x%lx has unknown "
+                                               "attribute type 0x%x.  "
+                                               "Aborting truncate.",
+                                               vi->i_ino,
+                                               le32_to_cpu(ni->type));
+                               err = -EIO;
+                       }
+                       /* Reset the vfs inode size to the old size. */
+                       i_size_write(vi, old_size);
+                       goto err_out;
+               }
+       }
+       if (NInoCompressed(ni) || NInoEncrypted(ni)) {
+               ntfs_warning(vi->i_sb, "Changes in inode size are not "
+                               "supported yet for %s files, ignoring.",
+                               NInoCompressed(ni) ? "compressed" :
+                               "encrypted");
+               err = -EOPNOTSUPP;
+               goto bad_out;
+       }
+       if (a->non_resident)
+               goto do_non_resident_truncate;
+       BUG_ON(NInoNonResident(ni));
+       /* Resize the attribute record to best fit the new attribute size. */
+       if (new_size < vol->mft_record_size &&
+                       !ntfs_resident_attr_value_resize(m, a, new_size)) {
+               unsigned long flags;
+
+               /* The resize succeeded! */
+               flush_dcache_mft_record_page(ctx->ntfs_ino);
+               mark_mft_record_dirty(ctx->ntfs_ino);
+               write_lock_irqsave(&ni->size_lock, flags);
+               /* Update the sizes in the ntfs inode and all is done. */
+               ni->allocated_size = le32_to_cpu(a->length) -
+                               le16_to_cpu(a->data.resident.value_offset);
+               /*
+                * Note ntfs_resident_attr_value_resize() has already done any
+                * necessary data clearing in the attribute record.  When the
+                * file is being shrunk vmtruncate() will already have cleared
+                * the top part of the last partial page, i.e. since this is
+                * the resident case this is the page with index 0.  However,
+                * when the file is being expanded, the page cache page data
+                * between the old data_size, i.e. old_size, and the new_size
+                * has not been zeroed.  Fortunately, we do not need to zero it
+                * either since on one hand it will either already be zero due
+                * to both readpage and writepage clearing partial page data
+                * beyond i_size in which case there is nothing to do or in the
+                * case of the file being mmap()ped at the same time, POSIX
+                * specifies that the behaviour is unspecified thus we do not
+                * have to do anything.  This means that in our implementation
+                * in the rare case that the file is mmap()ped and a write
+                * occured into the mmap()ped region just beyond the file size
+                * and writepage has not yet been called to write out the page
+                * (which would clear the area beyond the file size) and we now
+                * extend the file size to incorporate this dirty region
+                * outside the file size, a write of the page would result in
+                * this data being written to disk instead of being cleared.
+                * Given both POSIX and the Linux mmap(2) man page specify that
+                * this corner case is undefined, we choose to leave it like
+                * that as this is much simpler for us as we cannot lock the
+                * relevant page now since we are holding too many ntfs locks
+                * which would result in a lock reversal deadlock.
+                */
+               ni->initialized_size = new_size;
+               write_unlock_irqrestore(&ni->size_lock, flags);
+               goto unm_done;
+       }
+       /* If the above resize failed, this must be an attribute extension. */
+       BUG_ON(size_change < 0);
+       /*
+        * We have to drop all the locks so we can call
+        * ntfs_attr_make_non_resident().  This could be optimised by try-
+        * locking the first page cache page and only if that fails dropping
+        * the locks, locking the page, and redoing all the locking and
+        * lookups.  While this would be a huge optimisation, it is not worth
+        * it as this is definitely a slow code path as it only ever can happen
+        * once for any given file.
+        */
        ntfs_attr_put_search_ctx(ctx);
-       unmap_mft_record(ni);
-       NInoClearTruncateFailed(ni);
-       ntfs_debug("Done.");
-       return 0;
-err_out:
-       if (err != -ENOMEM) {
+       unmap_mft_record(base_ni);
+       up_write(&ni->runlist.lock);
+       /*
+        * Not enough space in the mft record, try to make the attribute
+        * non-resident and if successful restart the truncation process.
+        */
+       err = ntfs_attr_make_non_resident(ni, old_size);
+       if (likely(!err))
+               goto retry_truncate;
+       /*
+        * Could not make non-resident.  If this is due to this not being
+        * permitted for this attribute type or there not being enough space,
+        * try to make other attributes non-resident.  Otherwise fail.
+        */
+       if (unlikely(err != -EPERM && err != -ENOSPC)) {
+               ntfs_error(vol->sb, "Cannot truncate inode 0x%lx, attribute "
+                               "type 0x%x, because the conversion from "
+                               "resident to non-resident attribute failed "
+                               "with error code %i.", vi->i_ino,
+                               (unsigned)le32_to_cpu(ni->type), err);
+               if (err != -ENOMEM)
+                       err = -EIO;
+               goto conv_err_out;
+       }
+       /* TODO: Not implemented from here, abort. */
+       if (err == -ENOSPC)
+               ntfs_error(vol->sb, "Not enough space in the mft record/on "
+                               "disk for the non-resident attribute value.  "
+                               "This case is not implemented yet.");
+       else /* if (err == -EPERM) */
+               ntfs_error(vol->sb, "This attribute type may not be "
+                               "non-resident.  This case is not implemented "
+                               "yet.");
+       err = -EOPNOTSUPP;
+       goto conv_err_out;
+#if 0
+       // TODO: Attempt to make other attributes non-resident.
+       if (!err)
+               goto do_resident_extend;
+       /*
+        * Both the attribute list attribute and the standard information
+        * attribute must remain in the base inode.  Thus, if this is one of
+        * these attributes, we have to try to move other attributes out into
+        * extent mft records instead.
+        */
+       if (ni->type == AT_ATTRIBUTE_LIST ||
+                       ni->type == AT_STANDARD_INFORMATION) {
+               // TODO: Attempt to move other attributes into extent mft
+               // records.
+               err = -EOPNOTSUPP;
+               if (!err)
+                       goto do_resident_extend;
+               goto err_out;
+       }
+       // TODO: Attempt to move this attribute to an extent mft record, but
+       // only if it is not already the only attribute in an mft record in
+       // which case there would be nothing to gain.
+       err = -EOPNOTSUPP;
+       if (!err)
+               goto do_resident_extend;
+       /* There is nothing we can do to make enough space. )-: */
+       goto err_out;
+#endif
+do_non_resident_truncate:
+       BUG_ON(!NInoNonResident(ni));
+       if (alloc_change < 0) {
+               highest_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn);
+               if (highest_vcn > 0 &&
+                               old_alloc_size >> vol->cluster_size_bits >
+                               highest_vcn + 1) {
+                       /*
+                        * This attribute has multiple extents.  Not yet
+                        * supported.
+                        */
+                       ntfs_error(vol->sb, "Cannot truncate inode 0x%lx, "
+                                       "attribute type 0x%x, because the "
+                                       "attribute is highly fragmented (it "
+                                       "consists of multiple extents) and "
+                                       "this case is not implemented yet.",
+                                       vi->i_ino,
+                                       (unsigned)le32_to_cpu(ni->type));
+                       err = -EOPNOTSUPP;
+                       goto bad_out;
+               }
+       }
+       /*
+        * If the size is shrinking, need to reduce the initialized_size and
+        * the data_size before reducing the allocation.
+        */
+       if (size_change < 0) {
+               /*
+                * Make the valid size smaller (i_size is already up-to-date).
+                */
+               write_lock_irqsave(&ni->size_lock, flags);
+               if (new_size < ni->initialized_size) {
+                       ni->initialized_size = new_size;
+                       a->data.non_resident.initialized_size =
+                                       cpu_to_sle64(new_size);
+               }
+               a->data.non_resident.data_size = cpu_to_sle64(new_size);
+               write_unlock_irqrestore(&ni->size_lock, flags);
+               flush_dcache_mft_record_page(ctx->ntfs_ino);
+               mark_mft_record_dirty(ctx->ntfs_ino);
+               /* If the allocated size is not changing, we are done. */
+               if (!alloc_change)
+                       goto unm_done;
+               /*
+                * If the size is shrinking it makes no sense for the
+                * allocation to be growing.
+                */
+               BUG_ON(alloc_change > 0);
+       } else /* if (size_change >= 0) */ {
+               /*
+                * The file size is growing or staying the same but the
+                * allocation can be shrinking, growing or staying the same.
+                */
+               if (alloc_change > 0) {
+                       /*
+                        * We need to extend the allocation and possibly update
+                        * the data size.  If we are updating the data size,
+                        * since we are not touching the initialized_size we do
+                        * not need to worry about the actual data on disk.
+                        * And as far as the page cache is concerned, there
+                        * will be no pages beyond the old data size and any
+                        * partial region in the last page between the old and
+                        * new data size (or the end of the page if the new
+                        * data size is outside the page) does not need to be
+                        * modified as explained above for the resident
+                        * attribute truncate case.  To do this, we simply drop
+                        * the locks we hold and leave all the work to our
+                        * friendly helper ntfs_attr_extend_allocation().
+                        */
+                       ntfs_attr_put_search_ctx(ctx);
+                       unmap_mft_record(base_ni);
+                       up_write(&ni->runlist.lock);
+                       err = ntfs_attr_extend_allocation(ni, new_size,
+                                       size_change > 0 ? new_size : -1, -1);
+                       /*
+                        * ntfs_attr_extend_allocation() will have done error
+                        * output already.
+                        */
+                       goto done;
+               }
+               if (!alloc_change)
+                       goto alloc_done;
+       }
+       /* alloc_change < 0 */
+       /* Free the clusters. */
+       nr_freed = ntfs_cluster_free(ni, new_alloc_size >>
+                       vol->cluster_size_bits, -1, ctx);
+       m = ctx->mrec;
+       a = ctx->attr;
+       if (unlikely(nr_freed < 0)) {
+               ntfs_error(vol->sb, "Failed to release cluster(s) (error code "
+                               "%lli).  Unmount and run chkdsk to recover "
+                               "the lost cluster(s).", (long long)nr_freed);
                NVolSetErrors(vol);
+               nr_freed = 0;
+       }
+       /* Truncate the runlist. */
+       err = ntfs_rl_truncate_nolock(vol, &ni->runlist,
+                       new_alloc_size >> vol->cluster_size_bits);
+       /*
+        * If the runlist truncation failed and/or the search context is no
+        * longer valid, we cannot resize the attribute record or build the
+        * mapping pairs array thus we mark the inode bad so that no access to
+        * the freed clusters can happen.
+        */
+       if (unlikely(err || IS_ERR(m))) {
+               ntfs_error(vol->sb, "Failed to %s (error code %li).%s",
+                               IS_ERR(m) ?
+                               "restore attribute search context" :
+                               "truncate attribute runlist",
+                               IS_ERR(m) ? PTR_ERR(m) : err, es);
+               err = -EIO;
+               goto bad_out;
+       }
+       /* Get the size for the shrunk mapping pairs array for the runlist. */
+       mp_size = ntfs_get_size_for_mapping_pairs(vol, ni->runlist.rl, 0, -1);
+       if (unlikely(mp_size <= 0)) {
+               ntfs_error(vol->sb, "Cannot shrink allocation of inode 0x%lx, "
+                               "attribute type 0x%x, because determining the "
+                               "size for the mapping pairs failed with error "
+                               "code %i.%s", vi->i_ino,
+                               (unsigned)le32_to_cpu(ni->type), mp_size, es);
+               err = -EIO;
+               goto bad_out;
+       }
+       /*
+        * Shrink the attribute record for the new mapping pairs array.  Note,
+        * this cannot fail since we are making the attribute smaller thus by
+        * definition there is enough space to do so.
+        */
+       attr_len = le32_to_cpu(a->length);
+       err = ntfs_attr_record_resize(m, a, mp_size +
+                       le16_to_cpu(a->data.non_resident.mapping_pairs_offset));
+       BUG_ON(err);
+       /*
+        * Generate the mapping pairs array directly into the attribute record.
+        */
+       err = ntfs_mapping_pairs_build(vol, (u8*)a +
+                       le16_to_cpu(a->data.non_resident.mapping_pairs_offset),
+                       mp_size, ni->runlist.rl, 0, -1, NULL);
+       if (unlikely(err)) {
+               ntfs_error(vol->sb, "Cannot shrink allocation of inode 0x%lx, "
+                               "attribute type 0x%x, because building the "
+                               "mapping pairs failed with error code %i.%s",
+                               vi->i_ino, (unsigned)le32_to_cpu(ni->type),
+                               err, es);
+               err = -EIO;
+               goto bad_out;
+       }
+       /* Update the allocated/compressed size as well as the highest vcn. */
+       a->data.non_resident.highest_vcn = cpu_to_sle64((new_alloc_size >>
+                       vol->cluster_size_bits) - 1);
+       write_lock_irqsave(&ni->size_lock, flags);
+       ni->allocated_size = new_alloc_size;
+       a->data.non_resident.allocated_size = cpu_to_sle64(new_alloc_size);
+       if (NInoSparse(ni) || NInoCompressed(ni)) {
+               if (nr_freed) {
+                       ni->itype.compressed.size -= nr_freed <<
+                                       vol->cluster_size_bits;
+                       BUG_ON(ni->itype.compressed.size < 0);
+                       a->data.non_resident.compressed_size = cpu_to_sle64(
+                                       ni->itype.compressed.size);
+                       vi->i_blocks = ni->itype.compressed.size >> 9;
+               }
+       } else
+               vi->i_blocks = new_alloc_size >> 9;
+       write_unlock_irqrestore(&ni->size_lock, flags);
+       /*
+        * We have shrunk the allocation.  If this is a shrinking truncate we
+        * have already dealt with the initialized_size and the data_size above
+        * and we are done.  If the truncate is only changing the allocation
+        * and not the data_size, we are also done.  If this is an extending
+        * truncate, need to extend the data_size now which is ensured by the
+        * fact that @size_change is positive.
+        */
+alloc_done:
+       /*
+        * If the size is growing, need to update it now.  If it is shrinking,
+        * we have already updated it above (before the allocation change).
+        */
+       if (size_change > 0)
+               a->data.non_resident.data_size = cpu_to_sle64(new_size);
+       /* Ensure the modified mft record is written out. */
+       flush_dcache_mft_record_page(ctx->ntfs_ino);
+       mark_mft_record_dirty(ctx->ntfs_ino);
+unm_done:
+       ntfs_attr_put_search_ctx(ctx);
+       unmap_mft_record(base_ni);
+       up_write(&ni->runlist.lock);
+done:
+       /* Update the mtime and ctime on the base inode. */
+       inode_update_time(VFS_I(base_ni), 1);
+       if (likely(!err)) {
+               NInoClearTruncateFailed(ni);
+               ntfs_debug("Done.");
+       }
+       return err;
+old_bad_out:
+       old_size = -1;
+bad_out:
+       if (err != -ENOMEM && err != -EOPNOTSUPP) {
                make_bad_inode(vi);
+               make_bad_inode(VFS_I(base_ni));
+               NVolSetErrors(vol);
        }
+       if (err != -EOPNOTSUPP)
+               NInoSetTruncateFailed(ni);
+       else if (old_size >= 0)
+               i_size_write(vi, old_size);
+err_out:
        if (ctx)
                ntfs_attr_put_search_ctx(ctx);
        if (m)
-               unmap_mft_record(ni);
-       NInoSetTruncateFailed(ni);
+               unmap_mft_record(base_ni);
+       up_write(&ni->runlist.lock);
+out:
+       ntfs_debug("Failed.  Returning error code %i.", err);
        return err;
+conv_err_out:
+       if (err != -ENOMEM && err != -EOPNOTSUPP) {
+               make_bad_inode(vi);
+               make_bad_inode(VFS_I(base_ni));
+               NVolSetErrors(vol);
+       }
+       if (err != -EOPNOTSUPP)
+               NInoSetTruncateFailed(ni);
+       else
+               i_size_write(vi, old_size);
+       goto out;
 }
 
 /**
@@ -2420,8 +2845,7 @@ int ntfs_setattr(struct dentry *dentry, struct iattr *attr)
 
        err = inode_change_ok(vi, attr);
        if (err)
-               return err;
-
+               goto out;
        /* We do not support NTFS ACLs yet. */
        if (ia_valid & (ATTR_UID | ATTR_GID | ATTR_MODE)) {
                ntfs_warning(vi->i_sb, "Changes in user/group/mode are not "
@@ -2429,14 +2853,22 @@ int ntfs_setattr(struct dentry *dentry, struct iattr *attr)
                err = -EOPNOTSUPP;
                goto out;
        }
-
        if (ia_valid & ATTR_SIZE) {
                if (attr->ia_size != i_size_read(vi)) {
-                       ntfs_warning(vi->i_sb, "Changes in inode size are not "
-                                       "supported yet, ignoring.");
-                       err = -EOPNOTSUPP;
-                       // TODO: Implement...
-                       // err = vmtruncate(vi, attr->ia_size);
+                       ntfs_inode *ni = NTFS_I(vi);
+                       /*
+                        * FIXME: For now we do not support resizing of
+                        * compressed or encrypted files yet.
+                        */
+                       if (NInoCompressed(ni) || NInoEncrypted(ni)) {
+                               ntfs_warning(vi->i_sb, "Changes in inode size "
+                                               "are not supported yet for "
+                                               "%s files, ignoring.",
+                                               NInoCompressed(ni) ?
+                                               "compressed" : "encrypted");
+                               err = -EOPNOTSUPP;
+                       } else
+                               err = vmtruncate(vi, attr->ia_size);
                        if (err || ia_valid == ATTR_SIZE)
                                goto out;
                } else {
index 5af3bf0b7eee15220a26841ad0812c6766720f38..29cabf93d2d24ed66ffd0aff3a5478163e93f210 100644 (file)
@@ -76,6 +76,7 @@ int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
  * @count:     number of clusters to allocate
  * @start_lcn: starting lcn at which to allocate the clusters (or -1 if none)
  * @zone:      zone from which to allocate the clusters
+ * @is_extension:      if TRUE, this is an attribute extension
  *
  * Allocate @count clusters preferably starting at cluster @start_lcn or at the
  * current allocator position if @start_lcn is -1, on the mounted ntfs volume
@@ -86,6 +87,13 @@ int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
  * @start_vcn specifies the vcn of the first allocated cluster.  This makes
  * merging the resulting runlist with the old runlist easier.
  *
+ * If @is_extension is TRUE, the caller is allocating clusters to extend an
+ * attribute and if it is FALSE, the caller is allocating clusters to fill a
+ * hole in an attribute.  Practically the difference is that if @is_extension
+ * is TRUE the returned runlist will be terminated with LCN_ENOENT and if
+ * @is_extension is FALSE the runlist will be terminated with
+ * LCN_RL_NOT_MAPPED.
+ *
  * You need to check the return value with IS_ERR().  If this is false, the
  * function was successful and the return value is a runlist describing the
  * allocated cluster(s).  If IS_ERR() is true, the function failed and
@@ -137,7 +145,8 @@ int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
  */
 runlist_element *ntfs_cluster_alloc(ntfs_volume *vol, const VCN start_vcn,
                const s64 count, const LCN start_lcn,
-               const NTFS_CLUSTER_ALLOCATION_ZONES zone)
+               const NTFS_CLUSTER_ALLOCATION_ZONES zone,
+               const BOOL is_extension)
 {
        LCN zone_start, zone_end, bmp_pos, bmp_initial_pos, last_read_pos, lcn;
        LCN prev_lcn = 0, prev_run_len = 0, mft_zone_size;
@@ -310,7 +319,7 @@ runlist_element *ntfs_cluster_alloc(ntfs_volume *vol, const VCN start_vcn,
                                continue;
                        }
                        bit = 1 << (lcn & 7);
-                       ntfs_debug("bit %i.", bit);
+                       ntfs_debug("bit 0x%x.", bit);
                        /* If the bit is already set, go onto the next one. */
                        if (*byte & bit) {
                                lcn++;
@@ -729,7 +738,7 @@ out:
        /* Add runlist terminator element. */
        if (likely(rl)) {
                rl[rlpos].vcn = rl[rlpos - 1].vcn + rl[rlpos - 1].length;
-               rl[rlpos].lcn = LCN_RL_NOT_MAPPED;
+               rl[rlpos].lcn = is_extension ? LCN_ENOENT : LCN_RL_NOT_MAPPED;
                rl[rlpos].length = 0;
        }
        if (likely(page && !IS_ERR(page))) {
@@ -782,6 +791,7 @@ out:
  * @ni:                ntfs inode whose runlist describes the clusters to free
  * @start_vcn: vcn in the runlist of @ni at which to start freeing clusters
  * @count:     number of clusters to free or -1 for all clusters
+ * @ctx:       active attribute search context if present or NULL if not
  * @is_rollback:       true if this is a rollback operation
  *
  * Free @count clusters starting at the cluster @start_vcn in the runlist
@@ -791,15 +801,39 @@ out:
  * deallocated.  Thus, to completely free all clusters in a runlist, use
  * @start_vcn = 0 and @count = -1.
  *
+ * If @ctx is specified, it is an active search context of @ni and its base mft
+ * record.  This is needed when __ntfs_cluster_free() encounters unmapped
+ * runlist fragments and allows their mapping.  If you do not have the mft
+ * record mapped, you can specify @ctx as NULL and __ntfs_cluster_free() will
+ * perform the necessary mapping and unmapping.
+ *
+ * Note, __ntfs_cluster_free() saves the state of @ctx on entry and restores it
+ * before returning.  Thus, @ctx will be left pointing to the same attribute on
+ * return as on entry.  However, the actual pointers in @ctx may point to
+ * different memory locations on return, so you must remember to reset any
+ * cached pointers from the @ctx, i.e. after the call to __ntfs_cluster_free(),
+ * you will probably want to do:
+ *     m = ctx->mrec;
+ *     a = ctx->attr;
+ * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
+ * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
+ *
  * @is_rollback should always be FALSE, it is for internal use to rollback
  * errors.  You probably want to use ntfs_cluster_free() instead.
  *
- * Note, ntfs_cluster_free() does not modify the runlist at all, so the caller
- * has to deal with it later.
+ * Note, __ntfs_cluster_free() does not modify the runlist, so you have to
+ * remove from the runlist or mark sparse the freed runs later.
  *
  * Return the number of deallocated clusters (not counting sparse ones) on
  * success and -errno on error.
  *
+ * WARNING: If @ctx is supplied, regardless of whether success or failure is
+ *         returned, you need to check IS_ERR(@ctx->mrec) and if TRUE the @ctx
+ *         is no longer valid, i.e. you need to either call
+ *         ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
+ *         In that case PTR_ERR(@ctx->mrec) will give you the error code for
+ *         why the mapping of the old inode failed.
+ *
  * Locking: - The runlist described by @ni must be locked for writing on entry
  *           and is locked on return.  Note the runlist may be modified when
  *           needed runlist fragments need to be mapped.
@@ -807,9 +841,13 @@ out:
  *           on return.
  *         - This function takes the volume lcn bitmap lock for writing and
  *           modifies the bitmap contents.
+ *         - If @ctx is NULL, the base mft record of @ni must not be mapped on
+ *           entry and it will be left unmapped on return.
+ *         - If @ctx is not NULL, the base mft record must be mapped on entry
+ *           and it will be left mapped on return.
  */
 s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn, s64 count,
-               const BOOL is_rollback)
+               ntfs_attr_search_ctx *ctx, const BOOL is_rollback)
 {
        s64 delta, to_free, total_freed, real_freed;
        ntfs_volume *vol;
@@ -839,7 +877,7 @@ s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn, s64 count,
 
        total_freed = real_freed = 0;
 
-       rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, TRUE);
+       rl = ntfs_attr_find_vcn_nolock(ni, start_vcn, ctx);
        if (IS_ERR(rl)) {
                if (!is_rollback)
                        ntfs_error(vol->sb, "Failed to find first runlist "
@@ -893,7 +931,7 @@ s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn, s64 count,
 
                        /* Attempt to map runlist. */
                        vcn = rl->vcn;
-                       rl = ntfs_attr_find_vcn_nolock(ni, vcn, TRUE);
+                       rl = ntfs_attr_find_vcn_nolock(ni, vcn, ctx);
                        if (IS_ERR(rl)) {
                                err = PTR_ERR(rl);
                                if (!is_rollback)
@@ -961,7 +999,7 @@ err_out:
         * If rollback fails, set the volume errors flag, emit an error
         * message, and return the error code.
         */
-       delta = __ntfs_cluster_free(ni, start_vcn, total_freed, TRUE);
+       delta = __ntfs_cluster_free(ni, start_vcn, total_freed, ctx, TRUE);
        if (delta < 0) {
                ntfs_error(vol->sb, "Failed to rollback (error %i).  Leaving "
                                "inconsistent metadata!  Unmount and run "
index a6a8827882e73c71705ebf9ec174805e0a75dc8e..72cbca7003b2de3ee54ffe4a358efac9e767f090 100644 (file)
@@ -27,6 +27,7 @@
 
 #include <linux/fs.h>
 
+#include "attrib.h"
 #include "types.h"
 #include "inode.h"
 #include "runlist.h"
@@ -41,16 +42,18 @@ typedef enum {
 
 extern runlist_element *ntfs_cluster_alloc(ntfs_volume *vol,
                const VCN start_vcn, const s64 count, const LCN start_lcn,
-               const NTFS_CLUSTER_ALLOCATION_ZONES zone);
+               const NTFS_CLUSTER_ALLOCATION_ZONES zone,
+               const BOOL is_extension);
 
 extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
-               s64 count, const BOOL is_rollback);
+               s64 count, ntfs_attr_search_ctx *ctx, const BOOL is_rollback);
 
 /**
  * ntfs_cluster_free - free clusters on an ntfs volume
  * @ni:                ntfs inode whose runlist describes the clusters to free
  * @start_vcn: vcn in the runlist of @ni at which to start freeing clusters
  * @count:     number of clusters to free or -1 for all clusters
+ * @ctx:       active attribute search context if present or NULL if not
  *
  * Free @count clusters starting at the cluster @start_vcn in the runlist
  * described by the ntfs inode @ni.
@@ -59,12 +62,36 @@ extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
  * deallocated.  Thus, to completely free all clusters in a runlist, use
  * @start_vcn = 0 and @count = -1.
  *
- * Note, ntfs_cluster_free() does not modify the runlist at all, so the caller
- * has to deal with it later.
+ * If @ctx is specified, it is an active search context of @ni and its base mft
+ * record.  This is needed when ntfs_cluster_free() encounters unmapped runlist
+ * fragments and allows their mapping.  If you do not have the mft record
+ * mapped, you can specify @ctx as NULL and ntfs_cluster_free() will perform
+ * the necessary mapping and unmapping.
+ *
+ * Note, ntfs_cluster_free() saves the state of @ctx on entry and restores it
+ * before returning.  Thus, @ctx will be left pointing to the same attribute on
+ * return as on entry.  However, the actual pointers in @ctx may point to
+ * different memory locations on return, so you must remember to reset any
+ * cached pointers from the @ctx, i.e. after the call to ntfs_cluster_free(),
+ * you will probably want to do:
+ *     m = ctx->mrec;
+ *     a = ctx->attr;
+ * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
+ * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
+ *
+ * Note, ntfs_cluster_free() does not modify the runlist, so you have to remove
+ * from the runlist or mark sparse the freed runs later.
  *
  * Return the number of deallocated clusters (not counting sparse ones) on
  * success and -errno on error.
  *
+ * WARNING: If @ctx is supplied, regardless of whether success or failure is
+ *         returned, you need to check IS_ERR(@ctx->mrec) and if TRUE the @ctx
+ *         is no longer valid, i.e. you need to either call
+ *         ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
+ *         In that case PTR_ERR(@ctx->mrec) will give you the error code for
+ *         why the mapping of the old inode failed.
+ *
  * Locking: - The runlist described by @ni must be locked for writing on entry
  *           and is locked on return.  Note the runlist may be modified when
  *           needed runlist fragments need to be mapped.
@@ -72,11 +99,15 @@ extern s64 __ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
  *           on return.
  *         - This function takes the volume lcn bitmap lock for writing and
  *           modifies the bitmap contents.
+ *         - If @ctx is NULL, the base mft record of @ni must not be mapped on
+ *           entry and it will be left unmapped on return.
+ *         - If @ctx is not NULL, the base mft record must be mapped on entry
+ *           and it will be left mapped on return.
  */
 static inline s64 ntfs_cluster_free(ntfs_inode *ni, const VCN start_vcn,
-               s64 count)
+               s64 count, ntfs_attr_search_ctx *ctx)
 {
-       return __ntfs_cluster_free(ni, start_vcn, count, FALSE);
+       return __ntfs_cluster_free(ni, start_vcn, count, ctx, FALSE);
 }
 
 extern int ntfs_cluster_free_from_rl_nolock(ntfs_volume *vol,
index 590887b943f511ca964bc1c4cd30dc4cf7e0b0fd..e38e402e410351c6a70ff9ae148f10133ee28177 100644 (file)
@@ -39,8 +39,7 @@
  * If there was insufficient memory to complete the request, return NULL.
  * Depending on @gfp_mask the allocation may be guaranteed to succeed.
  */
-static inline void *__ntfs_malloc(unsigned long size,
-               gfp_t gfp_mask)
+static inline void *__ntfs_malloc(unsigned long size, gfp_t gfp_mask)
 {
        if (likely(size <= PAGE_SIZE)) {
                BUG_ON(!size);
index b011369b59561139687e627f211207dc4edff72e..0c65cbb8c5cf675af8eba7b682fac412cfa27eee 100644 (file)
@@ -49,7 +49,8 @@ static inline MFT_RECORD *map_mft_record_page(ntfs_inode *ni)
        ntfs_volume *vol = ni->vol;
        struct inode *mft_vi = vol->mft_ino;
        struct page *page;
-       unsigned long index, ofs, end_index;
+       unsigned long index, end_index;
+       unsigned ofs;
 
        BUG_ON(ni->page);
        /*
@@ -1308,7 +1309,7 @@ static int ntfs_mft_bitmap_extend_allocation_nolock(ntfs_volume *vol)
        ll = mftbmp_ni->allocated_size;
        read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
        rl = ntfs_attr_find_vcn_nolock(mftbmp_ni,
-                       (ll - 1) >> vol->cluster_size_bits, TRUE);
+                       (ll - 1) >> vol->cluster_size_bits, NULL);
        if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
                up_write(&mftbmp_ni->runlist.lock);
                ntfs_error(vol->sb, "Failed to determine last allocated "
@@ -1354,7 +1355,8 @@ static int ntfs_mft_bitmap_extend_allocation_nolock(ntfs_volume *vol)
                up_write(&vol->lcnbmp_lock);
                ntfs_unmap_page(page);
                /* Allocate a cluster from the DATA_ZONE. */
-               rl2 = ntfs_cluster_alloc(vol, rl[1].vcn, 1, lcn, DATA_ZONE);
+               rl2 = ntfs_cluster_alloc(vol, rl[1].vcn, 1, lcn, DATA_ZONE,
+                               TRUE);
                if (IS_ERR(rl2)) {
                        up_write(&mftbmp_ni->runlist.lock);
                        ntfs_error(vol->sb, "Failed to allocate a cluster for "
@@ -1738,7 +1740,7 @@ static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
        ll = mft_ni->allocated_size;
        read_unlock_irqrestore(&mft_ni->size_lock, flags);
        rl = ntfs_attr_find_vcn_nolock(mft_ni,
-                       (ll - 1) >> vol->cluster_size_bits, TRUE);
+                       (ll - 1) >> vol->cluster_size_bits, NULL);
        if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
                up_write(&mft_ni->runlist.lock);
                ntfs_error(vol->sb, "Failed to determine last allocated "
@@ -1779,7 +1781,8 @@ static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
                        nr > min_nr ? "default" : "minimal", (long long)nr);
        old_last_vcn = rl[1].vcn;
        do {
-               rl2 = ntfs_cluster_alloc(vol, old_last_vcn, nr, lcn, MFT_ZONE);
+               rl2 = ntfs_cluster_alloc(vol, old_last_vcn, nr, lcn, MFT_ZONE,
+                               TRUE);
                if (likely(!IS_ERR(rl2)))
                        break;
                if (PTR_ERR(rl2) != -ENOSPC || nr == min_nr) {
@@ -1951,20 +1954,21 @@ restore_undo_alloc:
                NVolSetErrors(vol);
                return ret;
        }
-       a = ctx->attr;
-       a->data.non_resident.highest_vcn = cpu_to_sle64(old_last_vcn - 1);
+       ctx->attr->data.non_resident.highest_vcn =
+                       cpu_to_sle64(old_last_vcn - 1);
 undo_alloc:
-       if (ntfs_cluster_free(mft_ni, old_last_vcn, -1) < 0) {
+       if (ntfs_cluster_free(mft_ni, old_last_vcn, -1, ctx) < 0) {
                ntfs_error(vol->sb, "Failed to free clusters from mft data "
                                "attribute.%s", es);
                NVolSetErrors(vol);
        }
+       a = ctx->attr;
        if (ntfs_rl_truncate_nolock(vol, &mft_ni->runlist, old_last_vcn)) {
                ntfs_error(vol->sb, "Failed to truncate mft data attribute "
                                "runlist.%s", es);
                NVolSetErrors(vol);
        }
-       if (mp_rebuilt) {
+       if (mp_rebuilt && !IS_ERR(ctx->mrec)) {
                if (ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
                                a->data.non_resident.mapping_pairs_offset),
                                old_alen - le16_to_cpu(
@@ -1981,6 +1985,10 @@ undo_alloc:
                }
                flush_dcache_mft_record_page(ctx->ntfs_ino);
                mark_mft_record_dirty(ctx->ntfs_ino);
+       } else if (IS_ERR(ctx->mrec)) {
+               ntfs_error(vol->sb, "Failed to restore attribute search "
+                               "context.%s", es);
+               NVolSetErrors(vol);
        }
        if (ctx)
                ntfs_attr_put_search_ctx(ctx);