ext4: Fix spelling of CONTIG_FS_EXT3 to CONFIG_FS_EXT3
[linux-2.6.git] / fs / libfs.c
index 7de05f7..9e50bcf 100644 (file)
@@ -9,6 +9,8 @@
 #include <linux/vfs.h>
 #include <linux/mutex.h>
 #include <linux/exportfs.h>
+#include <linux/writeback.h>
+#include <linux/buffer_head.h>
 
 #include <asm/uaccess.h>
 
@@ -44,7 +46,7 @@ static int simple_delete_dentry(struct dentry *dentry)
  */
 struct dentry *simple_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 {
-       static struct dentry_operations simple_dentry_operations = {
+       static const struct dentry_operations simple_dentry_operations = {
                .d_delete = simple_delete_dentry,
        };
 
@@ -215,7 +217,7 @@ int get_sb_pseudo(struct file_system_type *fs_type, char *name,
                return PTR_ERR(s);
 
        s->s_flags = MS_NOUSER;
-       s->s_maxbytes = ~0ULL;
+       s->s_maxbytes = MAX_LFS_FILESIZE;
        s->s_blocksize = PAGE_SIZE;
        s->s_blocksize_bits = PAGE_SHIFT;
        s->s_magic = magic;
@@ -242,11 +244,11 @@ int get_sb_pseudo(struct file_system_type *fs_type, char *name,
        d_instantiate(dentry, root);
        s->s_root = dentry;
        s->s_flags |= MS_ACTIVE;
-       return simple_set_mnt(mnt, s);
+       simple_set_mnt(mnt, s);
+       return 0;
 
 Enomem:
-       up_write(&s->s_umount);
-       deactivate_super(s);
+       deactivate_locked_super(s);
        return -ENOMEM;
 }
 
@@ -336,72 +338,74 @@ int simple_readpage(struct file *file, struct page *page)
        return 0;
 }
 
-int simple_prepare_write(struct file *file, struct page *page,
-                       unsigned from, unsigned to)
-{
-       if (!PageUptodate(page)) {
-               if (to - from != PAGE_CACHE_SIZE)
-                       zero_user_segments(page,
-                               0, from,
-                               to, PAGE_CACHE_SIZE);
-       }
-       return 0;
-}
-
 int simple_write_begin(struct file *file, struct address_space *mapping,
                        loff_t pos, unsigned len, unsigned flags,
                        struct page **pagep, void **fsdata)
 {
        struct page *page;
        pgoff_t index;
-       unsigned from;
 
        index = pos >> PAGE_CACHE_SHIFT;
-       from = pos & (PAGE_CACHE_SIZE - 1);
 
-       page = __grab_cache_page(mapping, index);
+       page = grab_cache_page_write_begin(mapping, index, flags);
        if (!page)
                return -ENOMEM;
 
        *pagep = page;
 
-       return simple_prepare_write(file, page, from, from+len);
-}
+       if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
+               unsigned from = pos & (PAGE_CACHE_SIZE - 1);
 
-static int simple_commit_write(struct file *file, struct page *page,
-                              unsigned from, unsigned to)
-{
-       struct inode *inode = page->mapping->host;
-       loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
-
-       if (!PageUptodate(page))
-               SetPageUptodate(page);
-       /*
-        * No need to use i_size_read() here, the i_size
-        * cannot change under us because we hold the i_mutex.
-        */
-       if (pos > inode->i_size)
-               i_size_write(inode, pos);
-       set_page_dirty(page);
+               zero_user_segments(page, 0, from, from + len, PAGE_CACHE_SIZE);
+       }
        return 0;
 }
 
+/**
+ * simple_write_end - .write_end helper for non-block-device FSes
+ * @available: See .write_end of address_space_operations
+ * @file:              "
+ * @mapping:           "
+ * @pos:               "
+ * @len:               "
+ * @copied:            "
+ * @page:              "
+ * @fsdata:            "
+ *
+ * simple_write_end does the minimum needed for updating a page after writing is
+ * done. It has the same API signature as the .write_end of
+ * address_space_operations vector. So it can just be set onto .write_end for
+ * FSes that don't need any other processing. i_mutex is assumed to be held.
+ * Block based filesystems should use generic_write_end().
+ * NOTE: Even though i_size might get updated by this function, mark_inode_dirty
+ * is not called, so a filesystem that actually does store data in .write_inode
+ * should extend on what's done here with a call to mark_inode_dirty() in the
+ * case that i_size has changed.
+ */
 int simple_write_end(struct file *file, struct address_space *mapping,
                        loff_t pos, unsigned len, unsigned copied,
                        struct page *page, void *fsdata)
 {
-       unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+       struct inode *inode = page->mapping->host;
+       loff_t last_pos = pos + copied;
 
        /* zero the stale part of the page if we did a short copy */
        if (copied < len) {
-               void *kaddr = kmap_atomic(page, KM_USER0);
-               memset(kaddr + from + copied, 0, len - copied);
-               flush_dcache_page(page);
-               kunmap_atomic(kaddr, KM_USER0);
+               unsigned from = pos & (PAGE_CACHE_SIZE - 1);
+
+               zero_user(page, from + copied, len - copied);
        }
 
-       simple_commit_write(file, page, from, from+copied);
+       if (!PageUptodate(page))
+               SetPageUptodate(page);
+       /*
+        * No need to use i_size_read() here, the i_size
+        * cannot change under us because we hold the i_mutex.
+        */
+       if (last_pos > inode->i_size)
+               i_size_write(inode, last_pos);
 
+       set_page_dirty(page);
        unlock_page(page);
        page_cache_release(page);
 
@@ -525,14 +529,18 @@ ssize_t simple_read_from_buffer(void __user *to, size_t count, loff_t *ppos,
                                const void *from, size_t available)
 {
        loff_t pos = *ppos;
+       size_t ret;
+
        if (pos < 0)
                return -EINVAL;
-       if (pos >= available)
+       if (pos >= available || !count)
                return 0;
        if (count > available - pos)
                count = available - pos;
-       if (copy_to_user(to, from + pos, count))
+       ret = copy_to_user(to, from + pos, count);
+       if (ret == count)
                return -EFAULT;
+       count -= ret;
        *ppos = pos + count;
        return count;
 }
@@ -574,6 +582,21 @@ ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
  * possibly a read which collects the result - which is stored in a
  * file-local buffer.
  */
+
+void simple_transaction_set(struct file *file, size_t n)
+{
+       struct simple_transaction_argresp *ar = file->private_data;
+
+       BUG_ON(n > SIMPLE_TRANSACTION_LIMIT);
+
+       /*
+        * The barrier ensures that ar->size will really remain zero until
+        * ar->data is ready for reading.
+        */
+       smp_mb();
+       ar->size = n;
+}
+
 char *simple_transaction_get(struct file *file, const char __user *buf, size_t size)
 {
        struct simple_transaction_argresp *ar;
@@ -718,10 +741,11 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf,
        if (copy_from_user(attr->set_buf, buf, size))
                goto out;
 
-       ret = len; /* claim we got the whole input */
        attr->set_buf[size] = '\0';
        val = simple_strtol(attr->set_buf, NULL, 0);
-       attr->set(attr->data, val);
+       ret = attr->set(attr->data, val);
+       if (ret == 0)
+               ret = len; /* on success, claim we got the whole input */
 out:
        mutex_unlock(&attr->mutex);
        return ret;
@@ -792,6 +816,29 @@ struct dentry *generic_fh_to_parent(struct super_block *sb, struct fid *fid,
 }
 EXPORT_SYMBOL_GPL(generic_fh_to_parent);
 
+int simple_fsync(struct file *file, struct dentry *dentry, int datasync)
+{
+       struct writeback_control wbc = {
+               .sync_mode = WB_SYNC_ALL,
+               .nr_to_write = 0, /* metadata-only; caller takes care of data */
+       };
+       struct inode *inode = dentry->d_inode;
+       int err;
+       int ret;
+
+       ret = sync_mapping_buffers(inode->i_mapping);
+       if (!(inode->i_state & I_DIRTY))
+               return ret;
+       if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
+               return ret;
+
+       err = sync_inode(inode, &wbc);
+       if (ret == 0)
+               ret = err;
+       return ret;
+}
+EXPORT_SYMBOL(simple_fsync);
+
 EXPORT_SYMBOL(dcache_dir_close);
 EXPORT_SYMBOL(dcache_dir_lseek);
 EXPORT_SYMBOL(dcache_dir_open);
@@ -803,13 +850,11 @@ EXPORT_SYMBOL(simple_write_end);
 EXPORT_SYMBOL(simple_dir_inode_operations);
 EXPORT_SYMBOL(simple_dir_operations);
 EXPORT_SYMBOL(simple_empty);
-EXPORT_SYMBOL(d_alloc_name);
 EXPORT_SYMBOL(simple_fill_super);
 EXPORT_SYMBOL(simple_getattr);
 EXPORT_SYMBOL(simple_link);
 EXPORT_SYMBOL(simple_lookup);
 EXPORT_SYMBOL(simple_pin_fs);
-EXPORT_UNUSED_SYMBOL(simple_prepare_write);
 EXPORT_SYMBOL(simple_readpage);
 EXPORT_SYMBOL(simple_release_fs);
 EXPORT_SYMBOL(simple_rename);
@@ -819,6 +864,7 @@ EXPORT_SYMBOL(simple_sync_file);
 EXPORT_SYMBOL(simple_unlink);
 EXPORT_SYMBOL(simple_read_from_buffer);
 EXPORT_SYMBOL(memory_read_from_buffer);
+EXPORT_SYMBOL(simple_transaction_set);
 EXPORT_SYMBOL(simple_transaction_get);
 EXPORT_SYMBOL(simple_transaction_read);
 EXPORT_SYMBOL(simple_transaction_release);