Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux...
[linux-2.6.git] / fs / btrfs / inode.c
1 /*
2  * Copyright (C) 2007 Oracle.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18
19 #include <linux/kernel.h>
20 #include <linux/bio.h>
21 #include <linux/buffer_head.h>
22 #include <linux/file.h>
23 #include <linux/fs.h>
24 #include <linux/pagemap.h>
25 #include <linux/highmem.h>
26 #include <linux/time.h>
27 #include <linux/init.h>
28 #include <linux/string.h>
29 #include <linux/backing-dev.h>
30 #include <linux/mpage.h>
31 #include <linux/swap.h>
32 #include <linux/writeback.h>
33 #include <linux/statfs.h>
34 #include <linux/compat.h>
35 #include <linux/bit_spinlock.h>
36 #include <linux/xattr.h>
37 #include <linux/posix_acl.h>
38 #include <linux/falloc.h>
39 #include <linux/slab.h>
40 #include <linux/ratelimit.h>
41 #include "compat.h"
42 #include "ctree.h"
43 #include "disk-io.h"
44 #include "transaction.h"
45 #include "btrfs_inode.h"
46 #include "ioctl.h"
47 #include "print-tree.h"
48 #include "ordered-data.h"
49 #include "xattr.h"
50 #include "tree-log.h"
51 #include "volumes.h"
52 #include "compression.h"
53 #include "locking.h"
54 #include "free-space-cache.h"
55 #include "inode-map.h"
56
57 struct btrfs_iget_args {
58         u64 ino;
59         struct btrfs_root *root;
60 };
61
62 static const struct inode_operations btrfs_dir_inode_operations;
63 static const struct inode_operations btrfs_symlink_inode_operations;
64 static const struct inode_operations btrfs_dir_ro_inode_operations;
65 static const struct inode_operations btrfs_special_inode_operations;
66 static const struct inode_operations btrfs_file_inode_operations;
67 static const struct address_space_operations btrfs_aops;
68 static const struct address_space_operations btrfs_symlink_aops;
69 static const struct file_operations btrfs_dir_file_operations;
70 static struct extent_io_ops btrfs_extent_io_ops;
71
72 static struct kmem_cache *btrfs_inode_cachep;
73 struct kmem_cache *btrfs_trans_handle_cachep;
74 struct kmem_cache *btrfs_transaction_cachep;
75 struct kmem_cache *btrfs_path_cachep;
76 struct kmem_cache *btrfs_free_space_cachep;
77
78 #define S_SHIFT 12
79 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
80         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
81         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
82         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
83         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
84         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
85         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
86         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
87 };
88
89 static int btrfs_setsize(struct inode *inode, loff_t newsize);
90 static int btrfs_truncate(struct inode *inode);
91 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end);
92 static noinline int cow_file_range(struct inode *inode,
93                                    struct page *locked_page,
94                                    u64 start, u64 end, int *page_started,
95                                    unsigned long *nr_written, int unlock);
96 static noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
97                                 struct btrfs_root *root, struct inode *inode);
98
99 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
100                                      struct inode *inode,  struct inode *dir,
101                                      const struct qstr *qstr)
102 {
103         int err;
104
105         err = btrfs_init_acl(trans, inode, dir);
106         if (!err)
107                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
108         return err;
109 }
110
111 /*
112  * this does all the hard work for inserting an inline extent into
113  * the btree.  The caller should have done a btrfs_drop_extents so that
114  * no overlapping inline items exist in the btree
115  */
116 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
117                                 struct btrfs_root *root, struct inode *inode,
118                                 u64 start, size_t size, size_t compressed_size,
119                                 int compress_type,
120                                 struct page **compressed_pages)
121 {
122         struct btrfs_key key;
123         struct btrfs_path *path;
124         struct extent_buffer *leaf;
125         struct page *page = NULL;
126         char *kaddr;
127         unsigned long ptr;
128         struct btrfs_file_extent_item *ei;
129         int err = 0;
130         int ret;
131         size_t cur_size = size;
132         size_t datasize;
133         unsigned long offset;
134
135         if (compressed_size && compressed_pages)
136                 cur_size = compressed_size;
137
138         path = btrfs_alloc_path();
139         if (!path)
140                 return -ENOMEM;
141
142         path->leave_spinning = 1;
143
144         key.objectid = btrfs_ino(inode);
145         key.offset = start;
146         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
147         datasize = btrfs_file_extent_calc_inline_size(cur_size);
148
149         inode_add_bytes(inode, size);
150         ret = btrfs_insert_empty_item(trans, root, path, &key,
151                                       datasize);
152         BUG_ON(ret);
153         if (ret) {
154                 err = ret;
155                 goto fail;
156         }
157         leaf = path->nodes[0];
158         ei = btrfs_item_ptr(leaf, path->slots[0],
159                             struct btrfs_file_extent_item);
160         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
161         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
162         btrfs_set_file_extent_encryption(leaf, ei, 0);
163         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
164         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
165         ptr = btrfs_file_extent_inline_start(ei);
166
167         if (compress_type != BTRFS_COMPRESS_NONE) {
168                 struct page *cpage;
169                 int i = 0;
170                 while (compressed_size > 0) {
171                         cpage = compressed_pages[i];
172                         cur_size = min_t(unsigned long, compressed_size,
173                                        PAGE_CACHE_SIZE);
174
175                         kaddr = kmap_atomic(cpage, KM_USER0);
176                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
177                         kunmap_atomic(kaddr, KM_USER0);
178
179                         i++;
180                         ptr += cur_size;
181                         compressed_size -= cur_size;
182                 }
183                 btrfs_set_file_extent_compression(leaf, ei,
184                                                   compress_type);
185         } else {
186                 page = find_get_page(inode->i_mapping,
187                                      start >> PAGE_CACHE_SHIFT);
188                 btrfs_set_file_extent_compression(leaf, ei, 0);
189                 kaddr = kmap_atomic(page, KM_USER0);
190                 offset = start & (PAGE_CACHE_SIZE - 1);
191                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
192                 kunmap_atomic(kaddr, KM_USER0);
193                 page_cache_release(page);
194         }
195         btrfs_mark_buffer_dirty(leaf);
196         btrfs_free_path(path);
197
198         /*
199          * we're an inline extent, so nobody can
200          * extend the file past i_size without locking
201          * a page we already have locked.
202          *
203          * We must do any isize and inode updates
204          * before we unlock the pages.  Otherwise we
205          * could end up racing with unlink.
206          */
207         BTRFS_I(inode)->disk_i_size = inode->i_size;
208         btrfs_update_inode(trans, root, inode);
209
210         return 0;
211 fail:
212         btrfs_free_path(path);
213         return err;
214 }
215
216
217 /*
218  * conditionally insert an inline extent into the file.  This
219  * does the checks required to make sure the data is small enough
220  * to fit as an inline extent.
221  */
222 static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans,
223                                  struct btrfs_root *root,
224                                  struct inode *inode, u64 start, u64 end,
225                                  size_t compressed_size, int compress_type,
226                                  struct page **compressed_pages)
227 {
228         u64 isize = i_size_read(inode);
229         u64 actual_end = min(end + 1, isize);
230         u64 inline_len = actual_end - start;
231         u64 aligned_end = (end + root->sectorsize - 1) &
232                         ~((u64)root->sectorsize - 1);
233         u64 hint_byte;
234         u64 data_len = inline_len;
235         int ret;
236
237         if (compressed_size)
238                 data_len = compressed_size;
239
240         if (start > 0 ||
241             actual_end >= PAGE_CACHE_SIZE ||
242             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
243             (!compressed_size &&
244             (actual_end & (root->sectorsize - 1)) == 0) ||
245             end + 1 < isize ||
246             data_len > root->fs_info->max_inline) {
247                 return 1;
248         }
249
250         ret = btrfs_drop_extents(trans, inode, start, aligned_end,
251                                  &hint_byte, 1);
252         BUG_ON(ret);
253
254         if (isize > actual_end)
255                 inline_len = min_t(u64, isize, actual_end);
256         ret = insert_inline_extent(trans, root, inode, start,
257                                    inline_len, compressed_size,
258                                    compress_type, compressed_pages);
259         BUG_ON(ret);
260         btrfs_delalloc_release_metadata(inode, end + 1 - start);
261         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
262         return 0;
263 }
264
265 struct async_extent {
266         u64 start;
267         u64 ram_size;
268         u64 compressed_size;
269         struct page **pages;
270         unsigned long nr_pages;
271         int compress_type;
272         struct list_head list;
273 };
274
275 struct async_cow {
276         struct inode *inode;
277         struct btrfs_root *root;
278         struct page *locked_page;
279         u64 start;
280         u64 end;
281         struct list_head extents;
282         struct btrfs_work work;
283 };
284
285 static noinline int add_async_extent(struct async_cow *cow,
286                                      u64 start, u64 ram_size,
287                                      u64 compressed_size,
288                                      struct page **pages,
289                                      unsigned long nr_pages,
290                                      int compress_type)
291 {
292         struct async_extent *async_extent;
293
294         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
295         BUG_ON(!async_extent);
296         async_extent->start = start;
297         async_extent->ram_size = ram_size;
298         async_extent->compressed_size = compressed_size;
299         async_extent->pages = pages;
300         async_extent->nr_pages = nr_pages;
301         async_extent->compress_type = compress_type;
302         list_add_tail(&async_extent->list, &cow->extents);
303         return 0;
304 }
305
306 /*
307  * we create compressed extents in two phases.  The first
308  * phase compresses a range of pages that have already been
309  * locked (both pages and state bits are locked).
310  *
311  * This is done inside an ordered work queue, and the compression
312  * is spread across many cpus.  The actual IO submission is step
313  * two, and the ordered work queue takes care of making sure that
314  * happens in the same order things were put onto the queue by
315  * writepages and friends.
316  *
317  * If this code finds it can't get good compression, it puts an
318  * entry onto the work queue to write the uncompressed bytes.  This
319  * makes sure that both compressed inodes and uncompressed inodes
320  * are written in the same order that pdflush sent them down.
321  */
322 static noinline int compress_file_range(struct inode *inode,
323                                         struct page *locked_page,
324                                         u64 start, u64 end,
325                                         struct async_cow *async_cow,
326                                         int *num_added)
327 {
328         struct btrfs_root *root = BTRFS_I(inode)->root;
329         struct btrfs_trans_handle *trans;
330         u64 num_bytes;
331         u64 blocksize = root->sectorsize;
332         u64 actual_end;
333         u64 isize = i_size_read(inode);
334         int ret = 0;
335         struct page **pages = NULL;
336         unsigned long nr_pages;
337         unsigned long nr_pages_ret = 0;
338         unsigned long total_compressed = 0;
339         unsigned long total_in = 0;
340         unsigned long max_compressed = 128 * 1024;
341         unsigned long max_uncompressed = 128 * 1024;
342         int i;
343         int will_compress;
344         int compress_type = root->fs_info->compress_type;
345
346         /* if this is a small write inside eof, kick off a defragbot */
347         if (end <= BTRFS_I(inode)->disk_i_size && (end - start + 1) < 16 * 1024)
348                 btrfs_add_inode_defrag(NULL, inode);
349
350         actual_end = min_t(u64, isize, end + 1);
351 again:
352         will_compress = 0;
353         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
354         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
355
356         /*
357          * we don't want to send crud past the end of i_size through
358          * compression, that's just a waste of CPU time.  So, if the
359          * end of the file is before the start of our current
360          * requested range of bytes, we bail out to the uncompressed
361          * cleanup code that can deal with all of this.
362          *
363          * It isn't really the fastest way to fix things, but this is a
364          * very uncommon corner.
365          */
366         if (actual_end <= start)
367                 goto cleanup_and_bail_uncompressed;
368
369         total_compressed = actual_end - start;
370
371         /* we want to make sure that amount of ram required to uncompress
372          * an extent is reasonable, so we limit the total size in ram
373          * of a compressed extent to 128k.  This is a crucial number
374          * because it also controls how easily we can spread reads across
375          * cpus for decompression.
376          *
377          * We also want to make sure the amount of IO required to do
378          * a random read is reasonably small, so we limit the size of
379          * a compressed extent to 128k.
380          */
381         total_compressed = min(total_compressed, max_uncompressed);
382         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
383         num_bytes = max(blocksize,  num_bytes);
384         total_in = 0;
385         ret = 0;
386
387         /*
388          * we do compression for mount -o compress and when the
389          * inode has not been flagged as nocompress.  This flag can
390          * change at any time if we discover bad compression ratios.
391          */
392         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
393             (btrfs_test_opt(root, COMPRESS) ||
394              (BTRFS_I(inode)->force_compress) ||
395              (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))) {
396                 WARN_ON(pages);
397                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
398                 if (!pages) {
399                         /* just bail out to the uncompressed code */
400                         goto cont;
401                 }
402
403                 if (BTRFS_I(inode)->force_compress)
404                         compress_type = BTRFS_I(inode)->force_compress;
405
406                 ret = btrfs_compress_pages(compress_type,
407                                            inode->i_mapping, start,
408                                            total_compressed, pages,
409                                            nr_pages, &nr_pages_ret,
410                                            &total_in,
411                                            &total_compressed,
412                                            max_compressed);
413
414                 if (!ret) {
415                         unsigned long offset = total_compressed &
416                                 (PAGE_CACHE_SIZE - 1);
417                         struct page *page = pages[nr_pages_ret - 1];
418                         char *kaddr;
419
420                         /* zero the tail end of the last page, we might be
421                          * sending it down to disk
422                          */
423                         if (offset) {
424                                 kaddr = kmap_atomic(page, KM_USER0);
425                                 memset(kaddr + offset, 0,
426                                        PAGE_CACHE_SIZE - offset);
427                                 kunmap_atomic(kaddr, KM_USER0);
428                         }
429                         will_compress = 1;
430                 }
431         }
432 cont:
433         if (start == 0) {
434                 trans = btrfs_join_transaction(root);
435                 BUG_ON(IS_ERR(trans));
436                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
437
438                 /* lets try to make an inline extent */
439                 if (ret || total_in < (actual_end - start)) {
440                         /* we didn't compress the entire range, try
441                          * to make an uncompressed inline extent.
442                          */
443                         ret = cow_file_range_inline(trans, root, inode,
444                                                     start, end, 0, 0, NULL);
445                 } else {
446                         /* try making a compressed inline extent */
447                         ret = cow_file_range_inline(trans, root, inode,
448                                                     start, end,
449                                                     total_compressed,
450                                                     compress_type, pages);
451                 }
452                 if (ret == 0) {
453                         /*
454                          * inline extent creation worked, we don't need
455                          * to create any more async work items.  Unlock
456                          * and free up our temp pages.
457                          */
458                         extent_clear_unlock_delalloc(inode,
459                              &BTRFS_I(inode)->io_tree,
460                              start, end, NULL,
461                              EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
462                              EXTENT_CLEAR_DELALLOC |
463                              EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK);
464
465                         btrfs_end_transaction(trans, root);
466                         goto free_pages_out;
467                 }
468                 btrfs_end_transaction(trans, root);
469         }
470
471         if (will_compress) {
472                 /*
473                  * we aren't doing an inline extent round the compressed size
474                  * up to a block size boundary so the allocator does sane
475                  * things
476                  */
477                 total_compressed = (total_compressed + blocksize - 1) &
478                         ~(blocksize - 1);
479
480                 /*
481                  * one last check to make sure the compression is really a
482                  * win, compare the page count read with the blocks on disk
483                  */
484                 total_in = (total_in + PAGE_CACHE_SIZE - 1) &
485                         ~(PAGE_CACHE_SIZE - 1);
486                 if (total_compressed >= total_in) {
487                         will_compress = 0;
488                 } else {
489                         num_bytes = total_in;
490                 }
491         }
492         if (!will_compress && pages) {
493                 /*
494                  * the compression code ran but failed to make things smaller,
495                  * free any pages it allocated and our page pointer array
496                  */
497                 for (i = 0; i < nr_pages_ret; i++) {
498                         WARN_ON(pages[i]->mapping);
499                         page_cache_release(pages[i]);
500                 }
501                 kfree(pages);
502                 pages = NULL;
503                 total_compressed = 0;
504                 nr_pages_ret = 0;
505
506                 /* flag the file so we don't compress in the future */
507                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
508                     !(BTRFS_I(inode)->force_compress)) {
509                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
510                 }
511         }
512         if (will_compress) {
513                 *num_added += 1;
514
515                 /* the async work queues will take care of doing actual
516                  * allocation on disk for these compressed pages,
517                  * and will submit them to the elevator.
518                  */
519                 add_async_extent(async_cow, start, num_bytes,
520                                  total_compressed, pages, nr_pages_ret,
521                                  compress_type);
522
523                 if (start + num_bytes < end) {
524                         start += num_bytes;
525                         pages = NULL;
526                         cond_resched();
527                         goto again;
528                 }
529         } else {
530 cleanup_and_bail_uncompressed:
531                 /*
532                  * No compression, but we still need to write the pages in
533                  * the file we've been given so far.  redirty the locked
534                  * page if it corresponds to our extent and set things up
535                  * for the async work queue to run cow_file_range to do
536                  * the normal delalloc dance
537                  */
538                 if (page_offset(locked_page) >= start &&
539                     page_offset(locked_page) <= end) {
540                         __set_page_dirty_nobuffers(locked_page);
541                         /* unlocked later on in the async handlers */
542                 }
543                 add_async_extent(async_cow, start, end - start + 1,
544                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
545                 *num_added += 1;
546         }
547
548 out:
549         return 0;
550
551 free_pages_out:
552         for (i = 0; i < nr_pages_ret; i++) {
553                 WARN_ON(pages[i]->mapping);
554                 page_cache_release(pages[i]);
555         }
556         kfree(pages);
557
558         goto out;
559 }
560
561 /*
562  * phase two of compressed writeback.  This is the ordered portion
563  * of the code, which only gets called in the order the work was
564  * queued.  We walk all the async extents created by compress_file_range
565  * and send them down to the disk.
566  */
567 static noinline int submit_compressed_extents(struct inode *inode,
568                                               struct async_cow *async_cow)
569 {
570         struct async_extent *async_extent;
571         u64 alloc_hint = 0;
572         struct btrfs_trans_handle *trans;
573         struct btrfs_key ins;
574         struct extent_map *em;
575         struct btrfs_root *root = BTRFS_I(inode)->root;
576         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
577         struct extent_io_tree *io_tree;
578         int ret = 0;
579
580         if (list_empty(&async_cow->extents))
581                 return 0;
582
583
584         while (!list_empty(&async_cow->extents)) {
585                 async_extent = list_entry(async_cow->extents.next,
586                                           struct async_extent, list);
587                 list_del(&async_extent->list);
588
589                 io_tree = &BTRFS_I(inode)->io_tree;
590
591 retry:
592                 /* did the compression code fall back to uncompressed IO? */
593                 if (!async_extent->pages) {
594                         int page_started = 0;
595                         unsigned long nr_written = 0;
596
597                         lock_extent(io_tree, async_extent->start,
598                                          async_extent->start +
599                                          async_extent->ram_size - 1, GFP_NOFS);
600
601                         /* allocate blocks */
602                         ret = cow_file_range(inode, async_cow->locked_page,
603                                              async_extent->start,
604                                              async_extent->start +
605                                              async_extent->ram_size - 1,
606                                              &page_started, &nr_written, 0);
607
608                         /*
609                          * if page_started, cow_file_range inserted an
610                          * inline extent and took care of all the unlocking
611                          * and IO for us.  Otherwise, we need to submit
612                          * all those pages down to the drive.
613                          */
614                         if (!page_started && !ret)
615                                 extent_write_locked_range(io_tree,
616                                                   inode, async_extent->start,
617                                                   async_extent->start +
618                                                   async_extent->ram_size - 1,
619                                                   btrfs_get_extent,
620                                                   WB_SYNC_ALL);
621                         kfree(async_extent);
622                         cond_resched();
623                         continue;
624                 }
625
626                 lock_extent(io_tree, async_extent->start,
627                             async_extent->start + async_extent->ram_size - 1,
628                             GFP_NOFS);
629
630                 trans = btrfs_join_transaction(root);
631                 BUG_ON(IS_ERR(trans));
632                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
633                 ret = btrfs_reserve_extent(trans, root,
634                                            async_extent->compressed_size,
635                                            async_extent->compressed_size,
636                                            0, alloc_hint,
637                                            (u64)-1, &ins, 1);
638                 btrfs_end_transaction(trans, root);
639
640                 if (ret) {
641                         int i;
642                         for (i = 0; i < async_extent->nr_pages; i++) {
643                                 WARN_ON(async_extent->pages[i]->mapping);
644                                 page_cache_release(async_extent->pages[i]);
645                         }
646                         kfree(async_extent->pages);
647                         async_extent->nr_pages = 0;
648                         async_extent->pages = NULL;
649                         unlock_extent(io_tree, async_extent->start,
650                                       async_extent->start +
651                                       async_extent->ram_size - 1, GFP_NOFS);
652                         goto retry;
653                 }
654
655                 /*
656                  * here we're doing allocation and writeback of the
657                  * compressed pages
658                  */
659                 btrfs_drop_extent_cache(inode, async_extent->start,
660                                         async_extent->start +
661                                         async_extent->ram_size - 1, 0);
662
663                 em = alloc_extent_map();
664                 BUG_ON(!em);
665                 em->start = async_extent->start;
666                 em->len = async_extent->ram_size;
667                 em->orig_start = em->start;
668
669                 em->block_start = ins.objectid;
670                 em->block_len = ins.offset;
671                 em->bdev = root->fs_info->fs_devices->latest_bdev;
672                 em->compress_type = async_extent->compress_type;
673                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
674                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
675
676                 while (1) {
677                         write_lock(&em_tree->lock);
678                         ret = add_extent_mapping(em_tree, em);
679                         write_unlock(&em_tree->lock);
680                         if (ret != -EEXIST) {
681                                 free_extent_map(em);
682                                 break;
683                         }
684                         btrfs_drop_extent_cache(inode, async_extent->start,
685                                                 async_extent->start +
686                                                 async_extent->ram_size - 1, 0);
687                 }
688
689                 ret = btrfs_add_ordered_extent_compress(inode,
690                                                 async_extent->start,
691                                                 ins.objectid,
692                                                 async_extent->ram_size,
693                                                 ins.offset,
694                                                 BTRFS_ORDERED_COMPRESSED,
695                                                 async_extent->compress_type);
696                 BUG_ON(ret);
697
698                 /*
699                  * clear dirty, set writeback and unlock the pages.
700                  */
701                 extent_clear_unlock_delalloc(inode,
702                                 &BTRFS_I(inode)->io_tree,
703                                 async_extent->start,
704                                 async_extent->start +
705                                 async_extent->ram_size - 1,
706                                 NULL, EXTENT_CLEAR_UNLOCK_PAGE |
707                                 EXTENT_CLEAR_UNLOCK |
708                                 EXTENT_CLEAR_DELALLOC |
709                                 EXTENT_CLEAR_DIRTY | EXTENT_SET_WRITEBACK);
710
711                 ret = btrfs_submit_compressed_write(inode,
712                                     async_extent->start,
713                                     async_extent->ram_size,
714                                     ins.objectid,
715                                     ins.offset, async_extent->pages,
716                                     async_extent->nr_pages);
717
718                 BUG_ON(ret);
719                 alloc_hint = ins.objectid + ins.offset;
720                 kfree(async_extent);
721                 cond_resched();
722         }
723
724         return 0;
725 }
726
727 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
728                                       u64 num_bytes)
729 {
730         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
731         struct extent_map *em;
732         u64 alloc_hint = 0;
733
734         read_lock(&em_tree->lock);
735         em = search_extent_mapping(em_tree, start, num_bytes);
736         if (em) {
737                 /*
738                  * if block start isn't an actual block number then find the
739                  * first block in this inode and use that as a hint.  If that
740                  * block is also bogus then just don't worry about it.
741                  */
742                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
743                         free_extent_map(em);
744                         em = search_extent_mapping(em_tree, 0, 0);
745                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
746                                 alloc_hint = em->block_start;
747                         if (em)
748                                 free_extent_map(em);
749                 } else {
750                         alloc_hint = em->block_start;
751                         free_extent_map(em);
752                 }
753         }
754         read_unlock(&em_tree->lock);
755
756         return alloc_hint;
757 }
758
759 /*
760  * when extent_io.c finds a delayed allocation range in the file,
761  * the call backs end up in this code.  The basic idea is to
762  * allocate extents on disk for the range, and create ordered data structs
763  * in ram to track those extents.
764  *
765  * locked_page is the page that writepage had locked already.  We use
766  * it to make sure we don't do extra locks or unlocks.
767  *
768  * *page_started is set to one if we unlock locked_page and do everything
769  * required to start IO on it.  It may be clean and already done with
770  * IO when we return.
771  */
772 static noinline int cow_file_range(struct inode *inode,
773                                    struct page *locked_page,
774                                    u64 start, u64 end, int *page_started,
775                                    unsigned long *nr_written,
776                                    int unlock)
777 {
778         struct btrfs_root *root = BTRFS_I(inode)->root;
779         struct btrfs_trans_handle *trans;
780         u64 alloc_hint = 0;
781         u64 num_bytes;
782         unsigned long ram_size;
783         u64 disk_num_bytes;
784         u64 cur_alloc_size;
785         u64 blocksize = root->sectorsize;
786         struct btrfs_key ins;
787         struct extent_map *em;
788         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
789         int ret = 0;
790
791         BUG_ON(btrfs_is_free_space_inode(root, inode));
792         trans = btrfs_join_transaction(root);
793         BUG_ON(IS_ERR(trans));
794         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
795
796         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
797         num_bytes = max(blocksize,  num_bytes);
798         disk_num_bytes = num_bytes;
799         ret = 0;
800
801         /* if this is a small write inside eof, kick off defrag */
802         if (end <= BTRFS_I(inode)->disk_i_size && num_bytes < 64 * 1024)
803                 btrfs_add_inode_defrag(trans, inode);
804
805         if (start == 0) {
806                 /* lets try to make an inline extent */
807                 ret = cow_file_range_inline(trans, root, inode,
808                                             start, end, 0, 0, NULL);
809                 if (ret == 0) {
810                         extent_clear_unlock_delalloc(inode,
811                                      &BTRFS_I(inode)->io_tree,
812                                      start, end, NULL,
813                                      EXTENT_CLEAR_UNLOCK_PAGE |
814                                      EXTENT_CLEAR_UNLOCK |
815                                      EXTENT_CLEAR_DELALLOC |
816                                      EXTENT_CLEAR_DIRTY |
817                                      EXTENT_SET_WRITEBACK |
818                                      EXTENT_END_WRITEBACK);
819
820                         *nr_written = *nr_written +
821                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
822                         *page_started = 1;
823                         ret = 0;
824                         goto out;
825                 }
826         }
827
828         BUG_ON(disk_num_bytes >
829                btrfs_super_total_bytes(root->fs_info->super_copy));
830
831         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
832         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
833
834         while (disk_num_bytes > 0) {
835                 unsigned long op;
836
837                 cur_alloc_size = disk_num_bytes;
838                 ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
839                                            root->sectorsize, 0, alloc_hint,
840                                            (u64)-1, &ins, 1);
841                 BUG_ON(ret);
842
843                 em = alloc_extent_map();
844                 BUG_ON(!em);
845                 em->start = start;
846                 em->orig_start = em->start;
847                 ram_size = ins.offset;
848                 em->len = ins.offset;
849
850                 em->block_start = ins.objectid;
851                 em->block_len = ins.offset;
852                 em->bdev = root->fs_info->fs_devices->latest_bdev;
853                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
854
855                 while (1) {
856                         write_lock(&em_tree->lock);
857                         ret = add_extent_mapping(em_tree, em);
858                         write_unlock(&em_tree->lock);
859                         if (ret != -EEXIST) {
860                                 free_extent_map(em);
861                                 break;
862                         }
863                         btrfs_drop_extent_cache(inode, start,
864                                                 start + ram_size - 1, 0);
865                 }
866
867                 cur_alloc_size = ins.offset;
868                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
869                                                ram_size, cur_alloc_size, 0);
870                 BUG_ON(ret);
871
872                 if (root->root_key.objectid ==
873                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
874                         ret = btrfs_reloc_clone_csums(inode, start,
875                                                       cur_alloc_size);
876                         BUG_ON(ret);
877                 }
878
879                 if (disk_num_bytes < cur_alloc_size)
880                         break;
881
882                 /* we're not doing compressed IO, don't unlock the first
883                  * page (which the caller expects to stay locked), don't
884                  * clear any dirty bits and don't set any writeback bits
885                  *
886                  * Do set the Private2 bit so we know this page was properly
887                  * setup for writepage
888                  */
889                 op = unlock ? EXTENT_CLEAR_UNLOCK_PAGE : 0;
890                 op |= EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
891                         EXTENT_SET_PRIVATE2;
892
893                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
894                                              start, start + ram_size - 1,
895                                              locked_page, op);
896                 disk_num_bytes -= cur_alloc_size;
897                 num_bytes -= cur_alloc_size;
898                 alloc_hint = ins.objectid + ins.offset;
899                 start += cur_alloc_size;
900         }
901 out:
902         ret = 0;
903         btrfs_end_transaction(trans, root);
904
905         return ret;
906 }
907
908 /*
909  * work queue call back to started compression on a file and pages
910  */
911 static noinline void async_cow_start(struct btrfs_work *work)
912 {
913         struct async_cow *async_cow;
914         int num_added = 0;
915         async_cow = container_of(work, struct async_cow, work);
916
917         compress_file_range(async_cow->inode, async_cow->locked_page,
918                             async_cow->start, async_cow->end, async_cow,
919                             &num_added);
920         if (num_added == 0)
921                 async_cow->inode = NULL;
922 }
923
924 /*
925  * work queue call back to submit previously compressed pages
926  */
927 static noinline void async_cow_submit(struct btrfs_work *work)
928 {
929         struct async_cow *async_cow;
930         struct btrfs_root *root;
931         unsigned long nr_pages;
932
933         async_cow = container_of(work, struct async_cow, work);
934
935         root = async_cow->root;
936         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
937                 PAGE_CACHE_SHIFT;
938
939         atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
940
941         if (atomic_read(&root->fs_info->async_delalloc_pages) <
942             5 * 1042 * 1024 &&
943             waitqueue_active(&root->fs_info->async_submit_wait))
944                 wake_up(&root->fs_info->async_submit_wait);
945
946         if (async_cow->inode)
947                 submit_compressed_extents(async_cow->inode, async_cow);
948 }
949
950 static noinline void async_cow_free(struct btrfs_work *work)
951 {
952         struct async_cow *async_cow;
953         async_cow = container_of(work, struct async_cow, work);
954         kfree(async_cow);
955 }
956
957 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
958                                 u64 start, u64 end, int *page_started,
959                                 unsigned long *nr_written)
960 {
961         struct async_cow *async_cow;
962         struct btrfs_root *root = BTRFS_I(inode)->root;
963         unsigned long nr_pages;
964         u64 cur_end;
965         int limit = 10 * 1024 * 1042;
966
967         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
968                          1, 0, NULL, GFP_NOFS);
969         while (start < end) {
970                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
971                 BUG_ON(!async_cow);
972                 async_cow->inode = inode;
973                 async_cow->root = root;
974                 async_cow->locked_page = locked_page;
975                 async_cow->start = start;
976
977                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
978                         cur_end = end;
979                 else
980                         cur_end = min(end, start + 512 * 1024 - 1);
981
982                 async_cow->end = cur_end;
983                 INIT_LIST_HEAD(&async_cow->extents);
984
985                 async_cow->work.func = async_cow_start;
986                 async_cow->work.ordered_func = async_cow_submit;
987                 async_cow->work.ordered_free = async_cow_free;
988                 async_cow->work.flags = 0;
989
990                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
991                         PAGE_CACHE_SHIFT;
992                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
993
994                 btrfs_queue_worker(&root->fs_info->delalloc_workers,
995                                    &async_cow->work);
996
997                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
998                         wait_event(root->fs_info->async_submit_wait,
999                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1000                             limit));
1001                 }
1002
1003                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1004                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1005                         wait_event(root->fs_info->async_submit_wait,
1006                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1007                            0));
1008                 }
1009
1010                 *nr_written += nr_pages;
1011                 start = cur_end + 1;
1012         }
1013         *page_started = 1;
1014         return 0;
1015 }
1016
1017 static noinline int csum_exist_in_range(struct btrfs_root *root,
1018                                         u64 bytenr, u64 num_bytes)
1019 {
1020         int ret;
1021         struct btrfs_ordered_sum *sums;
1022         LIST_HEAD(list);
1023
1024         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1025                                        bytenr + num_bytes - 1, &list, 0);
1026         if (ret == 0 && list_empty(&list))
1027                 return 0;
1028
1029         while (!list_empty(&list)) {
1030                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1031                 list_del(&sums->list);
1032                 kfree(sums);
1033         }
1034         return 1;
1035 }
1036
1037 /*
1038  * when nowcow writeback call back.  This checks for snapshots or COW copies
1039  * of the extents that exist in the file, and COWs the file as required.
1040  *
1041  * If no cow copies or snapshots exist, we write directly to the existing
1042  * blocks on disk
1043  */
1044 static noinline int run_delalloc_nocow(struct inode *inode,
1045                                        struct page *locked_page,
1046                               u64 start, u64 end, int *page_started, int force,
1047                               unsigned long *nr_written)
1048 {
1049         struct btrfs_root *root = BTRFS_I(inode)->root;
1050         struct btrfs_trans_handle *trans;
1051         struct extent_buffer *leaf;
1052         struct btrfs_path *path;
1053         struct btrfs_file_extent_item *fi;
1054         struct btrfs_key found_key;
1055         u64 cow_start;
1056         u64 cur_offset;
1057         u64 extent_end;
1058         u64 extent_offset;
1059         u64 disk_bytenr;
1060         u64 num_bytes;
1061         int extent_type;
1062         int ret;
1063         int type;
1064         int nocow;
1065         int check_prev = 1;
1066         bool nolock;
1067         u64 ino = btrfs_ino(inode);
1068
1069         path = btrfs_alloc_path();
1070         if (!path)
1071                 return -ENOMEM;
1072
1073         nolock = btrfs_is_free_space_inode(root, inode);
1074
1075         if (nolock)
1076                 trans = btrfs_join_transaction_nolock(root);
1077         else
1078                 trans = btrfs_join_transaction(root);
1079
1080         BUG_ON(IS_ERR(trans));
1081         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1082
1083         cow_start = (u64)-1;
1084         cur_offset = start;
1085         while (1) {
1086                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1087                                                cur_offset, 0);
1088                 BUG_ON(ret < 0);
1089                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1090                         leaf = path->nodes[0];
1091                         btrfs_item_key_to_cpu(leaf, &found_key,
1092                                               path->slots[0] - 1);
1093                         if (found_key.objectid == ino &&
1094                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1095                                 path->slots[0]--;
1096                 }
1097                 check_prev = 0;
1098 next_slot:
1099                 leaf = path->nodes[0];
1100                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1101                         ret = btrfs_next_leaf(root, path);
1102                         if (ret < 0)
1103                                 BUG_ON(1);
1104                         if (ret > 0)
1105                                 break;
1106                         leaf = path->nodes[0];
1107                 }
1108
1109                 nocow = 0;
1110                 disk_bytenr = 0;
1111                 num_bytes = 0;
1112                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1113
1114                 if (found_key.objectid > ino ||
1115                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1116                     found_key.offset > end)
1117                         break;
1118
1119                 if (found_key.offset > cur_offset) {
1120                         extent_end = found_key.offset;
1121                         extent_type = 0;
1122                         goto out_check;
1123                 }
1124
1125                 fi = btrfs_item_ptr(leaf, path->slots[0],
1126                                     struct btrfs_file_extent_item);
1127                 extent_type = btrfs_file_extent_type(leaf, fi);
1128
1129                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1130                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1131                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1132                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1133                         extent_end = found_key.offset +
1134                                 btrfs_file_extent_num_bytes(leaf, fi);
1135                         if (extent_end <= start) {
1136                                 path->slots[0]++;
1137                                 goto next_slot;
1138                         }
1139                         if (disk_bytenr == 0)
1140                                 goto out_check;
1141                         if (btrfs_file_extent_compression(leaf, fi) ||
1142                             btrfs_file_extent_encryption(leaf, fi) ||
1143                             btrfs_file_extent_other_encoding(leaf, fi))
1144                                 goto out_check;
1145                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1146                                 goto out_check;
1147                         if (btrfs_extent_readonly(root, disk_bytenr))
1148                                 goto out_check;
1149                         if (btrfs_cross_ref_exist(trans, root, ino,
1150                                                   found_key.offset -
1151                                                   extent_offset, disk_bytenr))
1152                                 goto out_check;
1153                         disk_bytenr += extent_offset;
1154                         disk_bytenr += cur_offset - found_key.offset;
1155                         num_bytes = min(end + 1, extent_end) - cur_offset;
1156                         /*
1157                          * force cow if csum exists in the range.
1158                          * this ensure that csum for a given extent are
1159                          * either valid or do not exist.
1160                          */
1161                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1162                                 goto out_check;
1163                         nocow = 1;
1164                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1165                         extent_end = found_key.offset +
1166                                 btrfs_file_extent_inline_len(leaf, fi);
1167                         extent_end = ALIGN(extent_end, root->sectorsize);
1168                 } else {
1169                         BUG_ON(1);
1170                 }
1171 out_check:
1172                 if (extent_end <= start) {
1173                         path->slots[0]++;
1174                         goto next_slot;
1175                 }
1176                 if (!nocow) {
1177                         if (cow_start == (u64)-1)
1178                                 cow_start = cur_offset;
1179                         cur_offset = extent_end;
1180                         if (cur_offset > end)
1181                                 break;
1182                         path->slots[0]++;
1183                         goto next_slot;
1184                 }
1185
1186                 btrfs_release_path(path);
1187                 if (cow_start != (u64)-1) {
1188                         ret = cow_file_range(inode, locked_page, cow_start,
1189                                         found_key.offset - 1, page_started,
1190                                         nr_written, 1);
1191                         BUG_ON(ret);
1192                         cow_start = (u64)-1;
1193                 }
1194
1195                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1196                         struct extent_map *em;
1197                         struct extent_map_tree *em_tree;
1198                         em_tree = &BTRFS_I(inode)->extent_tree;
1199                         em = alloc_extent_map();
1200                         BUG_ON(!em);
1201                         em->start = cur_offset;
1202                         em->orig_start = em->start;
1203                         em->len = num_bytes;
1204                         em->block_len = num_bytes;
1205                         em->block_start = disk_bytenr;
1206                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1207                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1208                         while (1) {
1209                                 write_lock(&em_tree->lock);
1210                                 ret = add_extent_mapping(em_tree, em);
1211                                 write_unlock(&em_tree->lock);
1212                                 if (ret != -EEXIST) {
1213                                         free_extent_map(em);
1214                                         break;
1215                                 }
1216                                 btrfs_drop_extent_cache(inode, em->start,
1217                                                 em->start + em->len - 1, 0);
1218                         }
1219                         type = BTRFS_ORDERED_PREALLOC;
1220                 } else {
1221                         type = BTRFS_ORDERED_NOCOW;
1222                 }
1223
1224                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1225                                                num_bytes, num_bytes, type);
1226                 BUG_ON(ret);
1227
1228                 if (root->root_key.objectid ==
1229                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1230                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1231                                                       num_bytes);
1232                         BUG_ON(ret);
1233                 }
1234
1235                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
1236                                 cur_offset, cur_offset + num_bytes - 1,
1237                                 locked_page, EXTENT_CLEAR_UNLOCK_PAGE |
1238                                 EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
1239                                 EXTENT_SET_PRIVATE2);
1240                 cur_offset = extent_end;
1241                 if (cur_offset > end)
1242                         break;
1243         }
1244         btrfs_release_path(path);
1245
1246         if (cur_offset <= end && cow_start == (u64)-1)
1247                 cow_start = cur_offset;
1248         if (cow_start != (u64)-1) {
1249                 ret = cow_file_range(inode, locked_page, cow_start, end,
1250                                      page_started, nr_written, 1);
1251                 BUG_ON(ret);
1252         }
1253
1254         if (nolock) {
1255                 ret = btrfs_end_transaction_nolock(trans, root);
1256                 BUG_ON(ret);
1257         } else {
1258                 ret = btrfs_end_transaction(trans, root);
1259                 BUG_ON(ret);
1260         }
1261         btrfs_free_path(path);
1262         return 0;
1263 }
1264
1265 /*
1266  * extent_io.c call back to do delayed allocation processing
1267  */
1268 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1269                               u64 start, u64 end, int *page_started,
1270                               unsigned long *nr_written)
1271 {
1272         int ret;
1273         struct btrfs_root *root = BTRFS_I(inode)->root;
1274
1275         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW)
1276                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1277                                          page_started, 1, nr_written);
1278         else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC)
1279                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1280                                          page_started, 0, nr_written);
1281         else if (!btrfs_test_opt(root, COMPRESS) &&
1282                  !(BTRFS_I(inode)->force_compress) &&
1283                  !(BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))
1284                 ret = cow_file_range(inode, locked_page, start, end,
1285                                       page_started, nr_written, 1);
1286         else
1287                 ret = cow_file_range_async(inode, locked_page, start, end,
1288                                            page_started, nr_written);
1289         return ret;
1290 }
1291
1292 static void btrfs_split_extent_hook(struct inode *inode,
1293                                     struct extent_state *orig, u64 split)
1294 {
1295         /* not delalloc, ignore it */
1296         if (!(orig->state & EXTENT_DELALLOC))
1297                 return;
1298
1299         spin_lock(&BTRFS_I(inode)->lock);
1300         BTRFS_I(inode)->outstanding_extents++;
1301         spin_unlock(&BTRFS_I(inode)->lock);
1302 }
1303
1304 /*
1305  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1306  * extents so we can keep track of new extents that are just merged onto old
1307  * extents, such as when we are doing sequential writes, so we can properly
1308  * account for the metadata space we'll need.
1309  */
1310 static void btrfs_merge_extent_hook(struct inode *inode,
1311                                     struct extent_state *new,
1312                                     struct extent_state *other)
1313 {
1314         /* not delalloc, ignore it */
1315         if (!(other->state & EXTENT_DELALLOC))
1316                 return;
1317
1318         spin_lock(&BTRFS_I(inode)->lock);
1319         BTRFS_I(inode)->outstanding_extents--;
1320         spin_unlock(&BTRFS_I(inode)->lock);
1321 }
1322
1323 /*
1324  * extent_io.c set_bit_hook, used to track delayed allocation
1325  * bytes in this file, and to maintain the list of inodes that
1326  * have pending delalloc work to be done.
1327  */
1328 static void btrfs_set_bit_hook(struct inode *inode,
1329                                struct extent_state *state, int *bits)
1330 {
1331
1332         /*
1333          * set_bit and clear bit hooks normally require _irqsave/restore
1334          * but in this case, we are only testing for the DELALLOC
1335          * bit, which is only set or cleared with irqs on
1336          */
1337         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1338                 struct btrfs_root *root = BTRFS_I(inode)->root;
1339                 u64 len = state->end + 1 - state->start;
1340                 bool do_list = !btrfs_is_free_space_inode(root, inode);
1341
1342                 if (*bits & EXTENT_FIRST_DELALLOC) {
1343                         *bits &= ~EXTENT_FIRST_DELALLOC;
1344                 } else {
1345                         spin_lock(&BTRFS_I(inode)->lock);
1346                         BTRFS_I(inode)->outstanding_extents++;
1347                         spin_unlock(&BTRFS_I(inode)->lock);
1348                 }
1349
1350                 spin_lock(&root->fs_info->delalloc_lock);
1351                 BTRFS_I(inode)->delalloc_bytes += len;
1352                 root->fs_info->delalloc_bytes += len;
1353                 if (do_list && list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1354                         list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1355                                       &root->fs_info->delalloc_inodes);
1356                 }
1357                 spin_unlock(&root->fs_info->delalloc_lock);
1358         }
1359 }
1360
1361 /*
1362  * extent_io.c clear_bit_hook, see set_bit_hook for why
1363  */
1364 static void btrfs_clear_bit_hook(struct inode *inode,
1365                                  struct extent_state *state, int *bits)
1366 {
1367         /*
1368          * set_bit and clear bit hooks normally require _irqsave/restore
1369          * but in this case, we are only testing for the DELALLOC
1370          * bit, which is only set or cleared with irqs on
1371          */
1372         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1373                 struct btrfs_root *root = BTRFS_I(inode)->root;
1374                 u64 len = state->end + 1 - state->start;
1375                 bool do_list = !btrfs_is_free_space_inode(root, inode);
1376
1377                 if (*bits & EXTENT_FIRST_DELALLOC) {
1378                         *bits &= ~EXTENT_FIRST_DELALLOC;
1379                 } else if (!(*bits & EXTENT_DO_ACCOUNTING)) {
1380                         spin_lock(&BTRFS_I(inode)->lock);
1381                         BTRFS_I(inode)->outstanding_extents--;
1382                         spin_unlock(&BTRFS_I(inode)->lock);
1383                 }
1384
1385                 if (*bits & EXTENT_DO_ACCOUNTING)
1386                         btrfs_delalloc_release_metadata(inode, len);
1387
1388                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1389                     && do_list)
1390                         btrfs_free_reserved_data_space(inode, len);
1391
1392                 spin_lock(&root->fs_info->delalloc_lock);
1393                 root->fs_info->delalloc_bytes -= len;
1394                 BTRFS_I(inode)->delalloc_bytes -= len;
1395
1396                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1397                     !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1398                         list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1399                 }
1400                 spin_unlock(&root->fs_info->delalloc_lock);
1401         }
1402 }
1403
1404 /*
1405  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1406  * we don't create bios that span stripes or chunks
1407  */
1408 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1409                          size_t size, struct bio *bio,
1410                          unsigned long bio_flags)
1411 {
1412         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1413         struct btrfs_mapping_tree *map_tree;
1414         u64 logical = (u64)bio->bi_sector << 9;
1415         u64 length = 0;
1416         u64 map_length;
1417         int ret;
1418
1419         if (bio_flags & EXTENT_BIO_COMPRESSED)
1420                 return 0;
1421
1422         length = bio->bi_size;
1423         map_tree = &root->fs_info->mapping_tree;
1424         map_length = length;
1425         ret = btrfs_map_block(map_tree, READ, logical,
1426                               &map_length, NULL, 0);
1427
1428         if (map_length < length + size)
1429                 return 1;
1430         return ret;
1431 }
1432
1433 /*
1434  * in order to insert checksums into the metadata in large chunks,
1435  * we wait until bio submission time.   All the pages in the bio are
1436  * checksummed and sums are attached onto the ordered extent record.
1437  *
1438  * At IO completion time the cums attached on the ordered extent record
1439  * are inserted into the btree
1440  */
1441 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1442                                     struct bio *bio, int mirror_num,
1443                                     unsigned long bio_flags,
1444                                     u64 bio_offset)
1445 {
1446         struct btrfs_root *root = BTRFS_I(inode)->root;
1447         int ret = 0;
1448
1449         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1450         BUG_ON(ret);
1451         return 0;
1452 }
1453
1454 /*
1455  * in order to insert checksums into the metadata in large chunks,
1456  * we wait until bio submission time.   All the pages in the bio are
1457  * checksummed and sums are attached onto the ordered extent record.
1458  *
1459  * At IO completion time the cums attached on the ordered extent record
1460  * are inserted into the btree
1461  */
1462 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1463                           int mirror_num, unsigned long bio_flags,
1464                           u64 bio_offset)
1465 {
1466         struct btrfs_root *root = BTRFS_I(inode)->root;
1467         return btrfs_map_bio(root, rw, bio, mirror_num, 1);
1468 }
1469
1470 /*
1471  * extent_io.c submission hook. This does the right thing for csum calculation
1472  * on write, or reading the csums from the tree before a read
1473  */
1474 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1475                           int mirror_num, unsigned long bio_flags,
1476                           u64 bio_offset)
1477 {
1478         struct btrfs_root *root = BTRFS_I(inode)->root;
1479         int ret = 0;
1480         int skip_sum;
1481
1482         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1483
1484         if (btrfs_is_free_space_inode(root, inode))
1485                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 2);
1486         else
1487                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
1488         BUG_ON(ret);
1489
1490         if (!(rw & REQ_WRITE)) {
1491                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1492                         return btrfs_submit_compressed_read(inode, bio,
1493                                                     mirror_num, bio_flags);
1494                 } else if (!skip_sum) {
1495                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1496                         if (ret)
1497                                 return ret;
1498                 }
1499                 goto mapit;
1500         } else if (!skip_sum) {
1501                 /* csum items have already been cloned */
1502                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1503                         goto mapit;
1504                 /* we're doing a write, do the async checksumming */
1505                 return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1506                                    inode, rw, bio, mirror_num,
1507                                    bio_flags, bio_offset,
1508                                    __btrfs_submit_bio_start,
1509                                    __btrfs_submit_bio_done);
1510         }
1511
1512 mapit:
1513         return btrfs_map_bio(root, rw, bio, mirror_num, 0);
1514 }
1515
1516 /*
1517  * given a list of ordered sums record them in the inode.  This happens
1518  * at IO completion time based on sums calculated at bio submission time.
1519  */
1520 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1521                              struct inode *inode, u64 file_offset,
1522                              struct list_head *list)
1523 {
1524         struct btrfs_ordered_sum *sum;
1525
1526         list_for_each_entry(sum, list, list) {
1527                 btrfs_csum_file_blocks(trans,
1528                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1529         }
1530         return 0;
1531 }
1532
1533 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1534                               struct extent_state **cached_state)
1535 {
1536         if ((end & (PAGE_CACHE_SIZE - 1)) == 0)
1537                 WARN_ON(1);
1538         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1539                                    cached_state, GFP_NOFS);
1540 }
1541
1542 /* see btrfs_writepage_start_hook for details on why this is required */
1543 struct btrfs_writepage_fixup {
1544         struct page *page;
1545         struct btrfs_work work;
1546 };
1547
1548 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1549 {
1550         struct btrfs_writepage_fixup *fixup;
1551         struct btrfs_ordered_extent *ordered;
1552         struct extent_state *cached_state = NULL;
1553         struct page *page;
1554         struct inode *inode;
1555         u64 page_start;
1556         u64 page_end;
1557
1558         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1559         page = fixup->page;
1560 again:
1561         lock_page(page);
1562         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1563                 ClearPageChecked(page);
1564                 goto out_page;
1565         }
1566
1567         inode = page->mapping->host;
1568         page_start = page_offset(page);
1569         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1570
1571         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1572                          &cached_state, GFP_NOFS);
1573
1574         /* already ordered? We're done */
1575         if (PagePrivate2(page))
1576                 goto out;
1577
1578         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1579         if (ordered) {
1580                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1581                                      page_end, &cached_state, GFP_NOFS);
1582                 unlock_page(page);
1583                 btrfs_start_ordered_extent(inode, ordered, 1);
1584                 goto again;
1585         }
1586
1587         BUG();
1588         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1589         ClearPageChecked(page);
1590 out:
1591         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1592                              &cached_state, GFP_NOFS);
1593 out_page:
1594         unlock_page(page);
1595         page_cache_release(page);
1596         kfree(fixup);
1597 }
1598
1599 /*
1600  * There are a few paths in the higher layers of the kernel that directly
1601  * set the page dirty bit without asking the filesystem if it is a
1602  * good idea.  This causes problems because we want to make sure COW
1603  * properly happens and the data=ordered rules are followed.
1604  *
1605  * In our case any range that doesn't have the ORDERED bit set
1606  * hasn't been properly setup for IO.  We kick off an async process
1607  * to fix it up.  The async helper will wait for ordered extents, set
1608  * the delalloc bit and make it safe to write the page.
1609  */
1610 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1611 {
1612         struct inode *inode = page->mapping->host;
1613         struct btrfs_writepage_fixup *fixup;
1614         struct btrfs_root *root = BTRFS_I(inode)->root;
1615
1616         /* this page is properly in the ordered list */
1617         if (TestClearPagePrivate2(page))
1618                 return 0;
1619
1620         if (PageChecked(page))
1621                 return -EAGAIN;
1622
1623         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1624         if (!fixup)
1625                 return -EAGAIN;
1626
1627         SetPageChecked(page);
1628         page_cache_get(page);
1629         fixup->work.func = btrfs_writepage_fixup_worker;
1630         fixup->page = page;
1631         btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
1632         return -EAGAIN;
1633 }
1634
1635 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1636                                        struct inode *inode, u64 file_pos,
1637                                        u64 disk_bytenr, u64 disk_num_bytes,
1638                                        u64 num_bytes, u64 ram_bytes,
1639                                        u8 compression, u8 encryption,
1640                                        u16 other_encoding, int extent_type)
1641 {
1642         struct btrfs_root *root = BTRFS_I(inode)->root;
1643         struct btrfs_file_extent_item *fi;
1644         struct btrfs_path *path;
1645         struct extent_buffer *leaf;
1646         struct btrfs_key ins;
1647         u64 hint;
1648         int ret;
1649
1650         path = btrfs_alloc_path();
1651         if (!path)
1652                 return -ENOMEM;
1653
1654         path->leave_spinning = 1;
1655
1656         /*
1657          * we may be replacing one extent in the tree with another.
1658          * The new extent is pinned in the extent map, and we don't want
1659          * to drop it from the cache until it is completely in the btree.
1660          *
1661          * So, tell btrfs_drop_extents to leave this extent in the cache.
1662          * the caller is expected to unpin it and allow it to be merged
1663          * with the others.
1664          */
1665         ret = btrfs_drop_extents(trans, inode, file_pos, file_pos + num_bytes,
1666                                  &hint, 0);
1667         BUG_ON(ret);
1668
1669         ins.objectid = btrfs_ino(inode);
1670         ins.offset = file_pos;
1671         ins.type = BTRFS_EXTENT_DATA_KEY;
1672         ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
1673         BUG_ON(ret);
1674         leaf = path->nodes[0];
1675         fi = btrfs_item_ptr(leaf, path->slots[0],
1676                             struct btrfs_file_extent_item);
1677         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1678         btrfs_set_file_extent_type(leaf, fi, extent_type);
1679         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1680         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1681         btrfs_set_file_extent_offset(leaf, fi, 0);
1682         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1683         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1684         btrfs_set_file_extent_compression(leaf, fi, compression);
1685         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1686         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1687
1688         btrfs_unlock_up_safe(path, 1);
1689         btrfs_set_lock_blocking(leaf);
1690
1691         btrfs_mark_buffer_dirty(leaf);
1692
1693         inode_add_bytes(inode, num_bytes);
1694
1695         ins.objectid = disk_bytenr;
1696         ins.offset = disk_num_bytes;
1697         ins.type = BTRFS_EXTENT_ITEM_KEY;
1698         ret = btrfs_alloc_reserved_file_extent(trans, root,
1699                                         root->root_key.objectid,
1700                                         btrfs_ino(inode), file_pos, &ins);
1701         BUG_ON(ret);
1702         btrfs_free_path(path);
1703
1704         return 0;
1705 }
1706
1707 /*
1708  * helper function for btrfs_finish_ordered_io, this
1709  * just reads in some of the csum leaves to prime them into ram
1710  * before we start the transaction.  It limits the amount of btree
1711  * reads required while inside the transaction.
1712  */
1713 /* as ordered data IO finishes, this gets called so we can finish
1714  * an ordered extent if the range of bytes in the file it covers are
1715  * fully written.
1716  */
1717 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
1718 {
1719         struct btrfs_root *root = BTRFS_I(inode)->root;
1720         struct btrfs_trans_handle *trans = NULL;
1721         struct btrfs_ordered_extent *ordered_extent = NULL;
1722         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1723         struct extent_state *cached_state = NULL;
1724         int compress_type = 0;
1725         int ret;
1726         bool nolock;
1727
1728         ret = btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
1729                                              end - start + 1);
1730         if (!ret)
1731                 return 0;
1732         BUG_ON(!ordered_extent);
1733
1734         nolock = btrfs_is_free_space_inode(root, inode);
1735
1736         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
1737                 BUG_ON(!list_empty(&ordered_extent->list));
1738                 ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1739                 if (!ret) {
1740                         if (nolock)
1741                                 trans = btrfs_join_transaction_nolock(root);
1742                         else
1743                                 trans = btrfs_join_transaction(root);
1744                         BUG_ON(IS_ERR(trans));
1745                         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1746                         ret = btrfs_update_inode_fallback(trans, root, inode);
1747                         BUG_ON(ret);
1748                 }
1749                 goto out;
1750         }
1751
1752         lock_extent_bits(io_tree, ordered_extent->file_offset,
1753                          ordered_extent->file_offset + ordered_extent->len - 1,
1754                          0, &cached_state, GFP_NOFS);
1755
1756         if (nolock)
1757                 trans = btrfs_join_transaction_nolock(root);
1758         else
1759                 trans = btrfs_join_transaction(root);
1760         BUG_ON(IS_ERR(trans));
1761         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1762
1763         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
1764                 compress_type = ordered_extent->compress_type;
1765         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1766                 BUG_ON(compress_type);
1767                 ret = btrfs_mark_extent_written(trans, inode,
1768                                                 ordered_extent->file_offset,
1769                                                 ordered_extent->file_offset +
1770                                                 ordered_extent->len);
1771                 BUG_ON(ret);
1772         } else {
1773                 BUG_ON(root == root->fs_info->tree_root);
1774                 ret = insert_reserved_file_extent(trans, inode,
1775                                                 ordered_extent->file_offset,
1776                                                 ordered_extent->start,
1777                                                 ordered_extent->disk_len,
1778                                                 ordered_extent->len,
1779                                                 ordered_extent->len,
1780                                                 compress_type, 0, 0,
1781                                                 BTRFS_FILE_EXTENT_REG);
1782                 unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
1783                                    ordered_extent->file_offset,
1784                                    ordered_extent->len);
1785                 BUG_ON(ret);
1786         }
1787         unlock_extent_cached(io_tree, ordered_extent->file_offset,
1788                              ordered_extent->file_offset +
1789                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
1790
1791         add_pending_csums(trans, inode, ordered_extent->file_offset,
1792                           &ordered_extent->list);
1793
1794         ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1795         if (!ret || !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1796                 ret = btrfs_update_inode_fallback(trans, root, inode);
1797                 BUG_ON(ret);
1798         }
1799         ret = 0;
1800 out:
1801         if (root != root->fs_info->tree_root)
1802                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
1803         if (trans) {
1804                 if (nolock)
1805                         btrfs_end_transaction_nolock(trans, root);
1806                 else
1807                         btrfs_end_transaction(trans, root);
1808         }
1809
1810         /* once for us */
1811         btrfs_put_ordered_extent(ordered_extent);
1812         /* once for the tree */
1813         btrfs_put_ordered_extent(ordered_extent);
1814
1815         return 0;
1816 }
1817
1818 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
1819                                 struct extent_state *state, int uptodate)
1820 {
1821         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
1822
1823         ClearPagePrivate2(page);
1824         return btrfs_finish_ordered_io(page->mapping->host, start, end);
1825 }
1826
1827 /*
1828  * when reads are done, we need to check csums to verify the data is correct
1829  * if there's a match, we allow the bio to finish.  If not, the code in
1830  * extent_io.c will try to find good copies for us.
1831  */
1832 static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
1833                                struct extent_state *state)
1834 {
1835         size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
1836         struct inode *inode = page->mapping->host;
1837         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1838         char *kaddr;
1839         u64 private = ~(u32)0;
1840         int ret;
1841         struct btrfs_root *root = BTRFS_I(inode)->root;
1842         u32 csum = ~(u32)0;
1843
1844         if (PageChecked(page)) {
1845                 ClearPageChecked(page);
1846                 goto good;
1847         }
1848
1849         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
1850                 goto good;
1851
1852         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
1853             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
1854                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
1855                                   GFP_NOFS);
1856                 return 0;
1857         }
1858
1859         if (state && state->start == start) {
1860                 private = state->private;
1861                 ret = 0;
1862         } else {
1863                 ret = get_state_private(io_tree, start, &private);
1864         }
1865         kaddr = kmap_atomic(page, KM_USER0);
1866         if (ret)
1867                 goto zeroit;
1868
1869         csum = btrfs_csum_data(root, kaddr + offset, csum,  end - start + 1);
1870         btrfs_csum_final(csum, (char *)&csum);
1871         if (csum != private)
1872                 goto zeroit;
1873
1874         kunmap_atomic(kaddr, KM_USER0);
1875 good:
1876         return 0;
1877
1878 zeroit:
1879         printk_ratelimited(KERN_INFO "btrfs csum failed ino %llu off %llu csum %u "
1880                        "private %llu\n",
1881                        (unsigned long long)btrfs_ino(page->mapping->host),
1882                        (unsigned long long)start, csum,
1883                        (unsigned long long)private);
1884         memset(kaddr + offset, 1, end - start + 1);
1885         flush_dcache_page(page);
1886         kunmap_atomic(kaddr, KM_USER0);
1887         if (private == 0)
1888                 return 0;
1889         return -EIO;
1890 }
1891
1892 struct delayed_iput {
1893         struct list_head list;
1894         struct inode *inode;
1895 };
1896
1897 void btrfs_add_delayed_iput(struct inode *inode)
1898 {
1899         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
1900         struct delayed_iput *delayed;
1901
1902         if (atomic_add_unless(&inode->i_count, -1, 1))
1903                 return;
1904
1905         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
1906         delayed->inode = inode;
1907
1908         spin_lock(&fs_info->delayed_iput_lock);
1909         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
1910         spin_unlock(&fs_info->delayed_iput_lock);
1911 }
1912
1913 void btrfs_run_delayed_iputs(struct btrfs_root *root)
1914 {
1915         LIST_HEAD(list);
1916         struct btrfs_fs_info *fs_info = root->fs_info;
1917         struct delayed_iput *delayed;
1918         int empty;
1919
1920         spin_lock(&fs_info->delayed_iput_lock);
1921         empty = list_empty(&fs_info->delayed_iputs);
1922         spin_unlock(&fs_info->delayed_iput_lock);
1923         if (empty)
1924                 return;
1925
1926         down_read(&root->fs_info->cleanup_work_sem);
1927         spin_lock(&fs_info->delayed_iput_lock);
1928         list_splice_init(&fs_info->delayed_iputs, &list);
1929         spin_unlock(&fs_info->delayed_iput_lock);
1930
1931         while (!list_empty(&list)) {
1932                 delayed = list_entry(list.next, struct delayed_iput, list);
1933                 list_del(&delayed->list);
1934                 iput(delayed->inode);
1935                 kfree(delayed);
1936         }
1937         up_read(&root->fs_info->cleanup_work_sem);
1938 }
1939
1940 enum btrfs_orphan_cleanup_state {
1941         ORPHAN_CLEANUP_STARTED  = 1,
1942         ORPHAN_CLEANUP_DONE     = 2,
1943 };
1944
1945 /*
1946  * This is called in transaction commmit time. If there are no orphan
1947  * files in the subvolume, it removes orphan item and frees block_rsv
1948  * structure.
1949  */
1950 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
1951                               struct btrfs_root *root)
1952 {
1953         int ret;
1954
1955         if (!list_empty(&root->orphan_list) ||
1956             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
1957                 return;
1958
1959         if (root->orphan_item_inserted &&
1960             btrfs_root_refs(&root->root_item) > 0) {
1961                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
1962                                             root->root_key.objectid);
1963                 BUG_ON(ret);
1964                 root->orphan_item_inserted = 0;
1965         }
1966
1967         if (root->orphan_block_rsv) {
1968                 WARN_ON(root->orphan_block_rsv->size > 0);
1969                 btrfs_free_block_rsv(root, root->orphan_block_rsv);
1970                 root->orphan_block_rsv = NULL;
1971         }
1972 }
1973
1974 /*
1975  * This creates an orphan entry for the given inode in case something goes
1976  * wrong in the middle of an unlink/truncate.
1977  *
1978  * NOTE: caller of this function should reserve 5 units of metadata for
1979  *       this function.
1980  */
1981 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
1982 {
1983         struct btrfs_root *root = BTRFS_I(inode)->root;
1984         struct btrfs_block_rsv *block_rsv = NULL;
1985         int reserve = 0;
1986         int insert = 0;
1987         int ret;
1988
1989         if (!root->orphan_block_rsv) {
1990                 block_rsv = btrfs_alloc_block_rsv(root);
1991                 if (!block_rsv)
1992                         return -ENOMEM;
1993         }
1994
1995         spin_lock(&root->orphan_lock);
1996         if (!root->orphan_block_rsv) {
1997                 root->orphan_block_rsv = block_rsv;
1998         } else if (block_rsv) {
1999                 btrfs_free_block_rsv(root, block_rsv);
2000                 block_rsv = NULL;
2001         }
2002
2003         if (list_empty(&BTRFS_I(inode)->i_orphan)) {
2004                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2005 #if 0
2006                 /*
2007                  * For proper ENOSPC handling, we should do orphan
2008                  * cleanup when mounting. But this introduces backward
2009                  * compatibility issue.
2010                  */
2011                 if (!xchg(&root->orphan_item_inserted, 1))
2012                         insert = 2;
2013                 else
2014                         insert = 1;
2015 #endif
2016                 insert = 1;
2017         }
2018
2019         if (!BTRFS_I(inode)->orphan_meta_reserved) {
2020                 BTRFS_I(inode)->orphan_meta_reserved = 1;
2021                 reserve = 1;
2022         }
2023         spin_unlock(&root->orphan_lock);
2024
2025         /* grab metadata reservation from transaction handle */
2026         if (reserve) {
2027                 ret = btrfs_orphan_reserve_metadata(trans, inode);
2028                 BUG_ON(ret);
2029         }
2030
2031         /* insert an orphan item to track this unlinked/truncated file */
2032         if (insert >= 1) {
2033                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
2034                 BUG_ON(ret);
2035         }
2036
2037         /* insert an orphan item to track subvolume contains orphan files */
2038         if (insert >= 2) {
2039                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2040                                                root->root_key.objectid);
2041                 BUG_ON(ret);
2042         }
2043         return 0;
2044 }
2045
2046 /*
2047  * We have done the truncate/delete so we can go ahead and remove the orphan
2048  * item for this particular inode.
2049  */
2050 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode)
2051 {
2052         struct btrfs_root *root = BTRFS_I(inode)->root;
2053         int delete_item = 0;
2054         int release_rsv = 0;
2055         int ret = 0;
2056
2057         spin_lock(&root->orphan_lock);
2058         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
2059                 list_del_init(&BTRFS_I(inode)->i_orphan);
2060                 delete_item = 1;
2061         }
2062
2063         if (BTRFS_I(inode)->orphan_meta_reserved) {
2064                 BTRFS_I(inode)->orphan_meta_reserved = 0;
2065                 release_rsv = 1;
2066         }
2067         spin_unlock(&root->orphan_lock);
2068
2069         if (trans && delete_item) {
2070                 ret = btrfs_del_orphan_item(trans, root, btrfs_ino(inode));
2071                 BUG_ON(ret);
2072         }
2073
2074         if (release_rsv)
2075                 btrfs_orphan_release_metadata(inode);
2076
2077         return 0;
2078 }
2079
2080 /*
2081  * this cleans up any orphans that may be left on the list from the last use
2082  * of this root.
2083  */
2084 int btrfs_orphan_cleanup(struct btrfs_root *root)
2085 {
2086         struct btrfs_path *path;
2087         struct extent_buffer *leaf;
2088         struct btrfs_key key, found_key;
2089         struct btrfs_trans_handle *trans;
2090         struct inode *inode;
2091         u64 last_objectid = 0;
2092         int ret = 0, nr_unlink = 0, nr_truncate = 0;
2093
2094         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
2095                 return 0;
2096
2097         path = btrfs_alloc_path();
2098         if (!path) {
2099                 ret = -ENOMEM;
2100                 goto out;
2101         }
2102         path->reada = -1;
2103
2104         key.objectid = BTRFS_ORPHAN_OBJECTID;
2105         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
2106         key.offset = (u64)-1;
2107
2108         while (1) {
2109                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2110                 if (ret < 0)
2111                         goto out;
2112
2113                 /*
2114                  * if ret == 0 means we found what we were searching for, which
2115                  * is weird, but possible, so only screw with path if we didn't
2116                  * find the key and see if we have stuff that matches
2117                  */
2118                 if (ret > 0) {
2119                         ret = 0;
2120                         if (path->slots[0] == 0)
2121                                 break;
2122                         path->slots[0]--;
2123                 }
2124
2125                 /* pull out the item */
2126                 leaf = path->nodes[0];
2127                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2128
2129                 /* make sure the item matches what we want */
2130                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
2131                         break;
2132                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
2133                         break;
2134
2135                 /* release the path since we're done with it */
2136                 btrfs_release_path(path);
2137
2138                 /*
2139                  * this is where we are basically btrfs_lookup, without the
2140                  * crossing root thing.  we store the inode number in the
2141                  * offset of the orphan item.
2142                  */
2143
2144                 if (found_key.offset == last_objectid) {
2145                         printk(KERN_ERR "btrfs: Error removing orphan entry, "
2146                                "stopping orphan cleanup\n");
2147                         ret = -EINVAL;
2148                         goto out;
2149                 }
2150
2151                 last_objectid = found_key.offset;
2152
2153                 found_key.objectid = found_key.offset;
2154                 found_key.type = BTRFS_INODE_ITEM_KEY;
2155                 found_key.offset = 0;
2156                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
2157                 ret = PTR_RET(inode);
2158                 if (ret && ret != -ESTALE)
2159                         goto out;
2160
2161                 /*
2162                  * Inode is already gone but the orphan item is still there,
2163                  * kill the orphan item.
2164                  */
2165                 if (ret == -ESTALE) {
2166                         trans = btrfs_start_transaction(root, 1);
2167                         if (IS_ERR(trans)) {
2168                                 ret = PTR_ERR(trans);
2169                                 goto out;
2170                         }
2171                         ret = btrfs_del_orphan_item(trans, root,
2172                                                     found_key.objectid);
2173                         BUG_ON(ret);
2174                         btrfs_end_transaction(trans, root);
2175                         continue;
2176                 }
2177
2178                 /*
2179                  * add this inode to the orphan list so btrfs_orphan_del does
2180                  * the proper thing when we hit it
2181                  */
2182                 spin_lock(&root->orphan_lock);
2183                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2184                 spin_unlock(&root->orphan_lock);
2185
2186                 /* if we have links, this was a truncate, lets do that */
2187                 if (inode->i_nlink) {
2188                         if (!S_ISREG(inode->i_mode)) {
2189                                 WARN_ON(1);
2190                                 iput(inode);
2191                                 continue;
2192                         }
2193                         nr_truncate++;
2194                         ret = btrfs_truncate(inode);
2195                 } else {
2196                         nr_unlink++;
2197                 }
2198
2199                 /* this will do delete_inode and everything for us */
2200                 iput(inode);
2201                 if (ret)
2202                         goto out;
2203         }
2204         /* release the path since we're done with it */
2205         btrfs_release_path(path);
2206
2207         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
2208
2209         if (root->orphan_block_rsv)
2210                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
2211                                         (u64)-1);
2212
2213         if (root->orphan_block_rsv || root->orphan_item_inserted) {
2214                 trans = btrfs_join_transaction(root);
2215                 if (!IS_ERR(trans))
2216                         btrfs_end_transaction(trans, root);
2217         }
2218
2219         if (nr_unlink)
2220                 printk(KERN_INFO "btrfs: unlinked %d orphans\n", nr_unlink);
2221         if (nr_truncate)
2222                 printk(KERN_INFO "btrfs: truncated %d orphans\n", nr_truncate);
2223
2224 out:
2225         if (ret)
2226                 printk(KERN_CRIT "btrfs: could not do orphan cleanup %d\n", ret);
2227         btrfs_free_path(path);
2228         return ret;
2229 }
2230
2231 /*
2232  * very simple check to peek ahead in the leaf looking for xattrs.  If we
2233  * don't find any xattrs, we know there can't be any acls.
2234  *
2235  * slot is the slot the inode is in, objectid is the objectid of the inode
2236  */
2237 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
2238                                           int slot, u64 objectid)
2239 {
2240         u32 nritems = btrfs_header_nritems(leaf);
2241         struct btrfs_key found_key;
2242         int scanned = 0;
2243
2244         slot++;
2245         while (slot < nritems) {
2246                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2247
2248                 /* we found a different objectid, there must not be acls */
2249                 if (found_key.objectid != objectid)
2250                         return 0;
2251
2252                 /* we found an xattr, assume we've got an acl */
2253                 if (found_key.type == BTRFS_XATTR_ITEM_KEY)
2254                         return 1;
2255
2256                 /*
2257                  * we found a key greater than an xattr key, there can't
2258                  * be any acls later on
2259                  */
2260                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
2261                         return 0;
2262
2263                 slot++;
2264                 scanned++;
2265
2266                 /*
2267                  * it goes inode, inode backrefs, xattrs, extents,
2268                  * so if there are a ton of hard links to an inode there can
2269                  * be a lot of backrefs.  Don't waste time searching too hard,
2270                  * this is just an optimization
2271                  */
2272                 if (scanned >= 8)
2273                         break;
2274         }
2275         /* we hit the end of the leaf before we found an xattr or
2276          * something larger than an xattr.  We have to assume the inode
2277          * has acls
2278          */
2279         return 1;
2280 }
2281
2282 /*
2283  * read an inode from the btree into the in-memory inode
2284  */
2285 static void btrfs_read_locked_inode(struct inode *inode)
2286 {
2287         struct btrfs_path *path;
2288         struct extent_buffer *leaf;
2289         struct btrfs_inode_item *inode_item;
2290         struct btrfs_timespec *tspec;
2291         struct btrfs_root *root = BTRFS_I(inode)->root;
2292         struct btrfs_key location;
2293         int maybe_acls;
2294         u32 rdev;
2295         int ret;
2296         bool filled = false;
2297
2298         ret = btrfs_fill_inode(inode, &rdev);
2299         if (!ret)
2300                 filled = true;
2301
2302         path = btrfs_alloc_path();
2303         if (!path)
2304                 goto make_bad;
2305
2306         path->leave_spinning = 1;
2307         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
2308
2309         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
2310         if (ret)
2311                 goto make_bad;
2312
2313         leaf = path->nodes[0];
2314
2315         if (filled)
2316                 goto cache_acl;
2317
2318         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2319                                     struct btrfs_inode_item);
2320         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
2321         set_nlink(inode, btrfs_inode_nlink(leaf, inode_item));
2322         inode->i_uid = btrfs_inode_uid(leaf, inode_item);
2323         inode->i_gid = btrfs_inode_gid(leaf, inode_item);
2324         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
2325
2326         tspec = btrfs_inode_atime(inode_item);
2327         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2328         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2329
2330         tspec = btrfs_inode_mtime(inode_item);
2331         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2332         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2333
2334         tspec = btrfs_inode_ctime(inode_item);
2335         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2336         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2337
2338         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
2339         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
2340         BTRFS_I(inode)->sequence = btrfs_inode_sequence(leaf, inode_item);
2341         inode->i_generation = BTRFS_I(inode)->generation;
2342         inode->i_rdev = 0;
2343         rdev = btrfs_inode_rdev(leaf, inode_item);
2344
2345         BTRFS_I(inode)->index_cnt = (u64)-1;
2346         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
2347 cache_acl:
2348         /*
2349          * try to precache a NULL acl entry for files that don't have
2350          * any xattrs or acls
2351          */
2352         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
2353                                            btrfs_ino(inode));
2354         if (!maybe_acls)
2355                 cache_no_acl(inode);
2356
2357         btrfs_free_path(path);
2358
2359         switch (inode->i_mode & S_IFMT) {
2360         case S_IFREG:
2361                 inode->i_mapping->a_ops = &btrfs_aops;
2362                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2363                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
2364                 inode->i_fop = &btrfs_file_operations;
2365                 inode->i_op = &btrfs_file_inode_operations;
2366                 break;
2367         case S_IFDIR:
2368                 inode->i_fop = &btrfs_dir_file_operations;
2369                 if (root == root->fs_info->tree_root)
2370                         inode->i_op = &btrfs_dir_ro_inode_operations;
2371                 else
2372                         inode->i_op = &btrfs_dir_inode_operations;
2373                 break;
2374         case S_IFLNK:
2375                 inode->i_op = &btrfs_symlink_inode_operations;
2376                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
2377                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2378                 break;
2379         default:
2380                 inode->i_op = &btrfs_special_inode_operations;
2381                 init_special_inode(inode, inode->i_mode, rdev);
2382                 break;
2383         }
2384
2385         btrfs_update_iflags(inode);
2386         return;
2387
2388 make_bad:
2389         btrfs_free_path(path);
2390         make_bad_inode(inode);
2391 }
2392
2393 /*
2394  * given a leaf and an inode, copy the inode fields into the leaf
2395  */
2396 static void fill_inode_item(struct btrfs_trans_handle *trans,
2397                             struct extent_buffer *leaf,
2398                             struct btrfs_inode_item *item,
2399                             struct inode *inode)
2400 {
2401         btrfs_set_inode_uid(leaf, item, inode->i_uid);
2402         btrfs_set_inode_gid(leaf, item, inode->i_gid);
2403         btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
2404         btrfs_set_inode_mode(leaf, item, inode->i_mode);
2405         btrfs_set_inode_nlink(leaf, item, inode->i_nlink);
2406
2407         btrfs_set_timespec_sec(leaf, btrfs_inode_atime(item),
2408                                inode->i_atime.tv_sec);
2409         btrfs_set_timespec_nsec(leaf, btrfs_inode_atime(item),
2410                                 inode->i_atime.tv_nsec);
2411
2412         btrfs_set_timespec_sec(leaf, btrfs_inode_mtime(item),
2413                                inode->i_mtime.tv_sec);
2414         btrfs_set_timespec_nsec(leaf, btrfs_inode_mtime(item),
2415                                 inode->i_mtime.tv_nsec);
2416
2417         btrfs_set_timespec_sec(leaf, btrfs_inode_ctime(item),
2418                                inode->i_ctime.tv_sec);
2419         btrfs_set_timespec_nsec(leaf, btrfs_inode_ctime(item),
2420                                 inode->i_ctime.tv_nsec);
2421
2422         btrfs_set_inode_nbytes(leaf, item, inode_get_bytes(inode));
2423         btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
2424         btrfs_set_inode_sequence(leaf, item, BTRFS_I(inode)->sequence);
2425         btrfs_set_inode_transid(leaf, item, trans->transid);
2426         btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
2427         btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
2428         btrfs_set_inode_block_group(leaf, item, 0);
2429 }
2430
2431 /*
2432  * copy everything in the in-memory inode into the btree.
2433  */
2434 static noinline int btrfs_update_inode_item(struct btrfs_trans_handle *trans,
2435                                 struct btrfs_root *root, struct inode *inode)
2436 {
2437         struct btrfs_inode_item *inode_item;
2438         struct btrfs_path *path;
2439         struct extent_buffer *leaf;
2440         int ret;
2441
2442         path = btrfs_alloc_path();
2443         if (!path)
2444                 return -ENOMEM;
2445
2446         path->leave_spinning = 1;
2447         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
2448                                  1);
2449         if (ret) {
2450                 if (ret > 0)
2451                         ret = -ENOENT;
2452                 goto failed;
2453         }
2454
2455         btrfs_unlock_up_safe(path, 1);
2456         leaf = path->nodes[0];
2457         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2458                                     struct btrfs_inode_item);
2459
2460         fill_inode_item(trans, leaf, inode_item, inode);
2461         btrfs_mark_buffer_dirty(leaf);
2462         btrfs_set_inode_last_trans(trans, inode);
2463         ret = 0;
2464 failed:
2465         btrfs_free_path(path);
2466         return ret;
2467 }
2468
2469 /*
2470  * copy everything in the in-memory inode into the btree.
2471  */
2472 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
2473                                 struct btrfs_root *root, struct inode *inode)
2474 {
2475         int ret;
2476
2477         /*
2478          * If the inode is a free space inode, we can deadlock during commit
2479          * if we put it into the delayed code.
2480          *
2481          * The data relocation inode should also be directly updated
2482          * without delay
2483          */
2484         if (!btrfs_is_free_space_inode(root, inode)
2485             && root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID) {
2486                 ret = btrfs_delayed_update_inode(trans, root, inode);
2487                 if (!ret)
2488                         btrfs_set_inode_last_trans(trans, inode);
2489                 return ret;
2490         }
2491
2492         return btrfs_update_inode_item(trans, root, inode);
2493 }
2494
2495 static noinline int btrfs_update_inode_fallback(struct btrfs_trans_handle *trans,
2496                                 struct btrfs_root *root, struct inode *inode)
2497 {
2498         int ret;
2499
2500         ret = btrfs_update_inode(trans, root, inode);
2501         if (ret == -ENOSPC)
2502                 return btrfs_update_inode_item(trans, root, inode);
2503         return ret;
2504 }
2505
2506 /*
2507  * unlink helper that gets used here in inode.c and in the tree logging
2508  * recovery code.  It remove a link in a directory with a given name, and
2509  * also drops the back refs in the inode to the directory
2510  */
2511 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2512                                 struct btrfs_root *root,
2513                                 struct inode *dir, struct inode *inode,
2514                                 const char *name, int name_len)
2515 {
2516         struct btrfs_path *path;
2517         int ret = 0;
2518         struct extent_buffer *leaf;
2519         struct btrfs_dir_item *di;
2520         struct btrfs_key key;
2521         u64 index;
2522         u64 ino = btrfs_ino(inode);
2523         u64 dir_ino = btrfs_ino(dir);
2524
2525         path = btrfs_alloc_path();
2526         if (!path) {
2527                 ret = -ENOMEM;
2528                 goto out;
2529         }
2530
2531         path->leave_spinning = 1;
2532         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2533                                     name, name_len, -1);
2534         if (IS_ERR(di)) {
2535                 ret = PTR_ERR(di);
2536                 goto err;
2537         }
2538         if (!di) {
2539                 ret = -ENOENT;
2540                 goto err;
2541         }
2542         leaf = path->nodes[0];
2543         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2544         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2545         if (ret)
2546                 goto err;
2547         btrfs_release_path(path);
2548
2549         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
2550                                   dir_ino, &index);
2551         if (ret) {
2552                 printk(KERN_INFO "btrfs failed to delete reference to %.*s, "
2553                        "inode %llu parent %llu\n", name_len, name,
2554                        (unsigned long long)ino, (unsigned long long)dir_ino);
2555                 goto err;
2556         }
2557
2558         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
2559         if (ret)
2560                 goto err;
2561
2562         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
2563                                          inode, dir_ino);
2564         BUG_ON(ret != 0 && ret != -ENOENT);
2565
2566         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
2567                                            dir, index);
2568         if (ret == -ENOENT)
2569                 ret = 0;
2570 err:
2571         btrfs_free_path(path);
2572         if (ret)
2573                 goto out;
2574
2575         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2576         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2577         btrfs_update_inode(trans, root, dir);
2578 out:
2579         return ret;
2580 }
2581
2582 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2583                        struct btrfs_root *root,
2584                        struct inode *dir, struct inode *inode,
2585                        const char *name, int name_len)
2586 {
2587         int ret;
2588         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
2589         if (!ret) {
2590                 btrfs_drop_nlink(inode);
2591                 ret = btrfs_update_inode(trans, root, inode);
2592         }
2593         return ret;
2594 }
2595                 
2596
2597 /* helper to check if there is any shared block in the path */
2598 static int check_path_shared(struct btrfs_root *root,
2599                              struct btrfs_path *path)
2600 {
2601         struct extent_buffer *eb;
2602         int level;
2603         u64 refs = 1;
2604
2605         for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2606                 int ret;
2607
2608                 if (!path->nodes[level])
2609                         break;
2610                 eb = path->nodes[level];
2611                 if (!btrfs_block_can_be_shared(root, eb))
2612                         continue;
2613                 ret = btrfs_lookup_extent_info(NULL, root, eb->start, eb->len,
2614                                                &refs, NULL);
2615                 if (refs > 1)
2616                         return 1;
2617         }
2618         return 0;
2619 }
2620
2621 /*
2622  * helper to start transaction for unlink and rmdir.
2623  *
2624  * unlink and rmdir are special in btrfs, they do not always free space.
2625  * so in enospc case, we should make sure they will free space before
2626  * allowing them to use the global metadata reservation.
2627  */
2628 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
2629                                                        struct dentry *dentry)
2630 {
2631         struct btrfs_trans_handle *trans;
2632         struct btrfs_root *root = BTRFS_I(dir)->root;
2633         struct btrfs_path *path;
2634         struct btrfs_inode_ref *ref;
2635         struct btrfs_dir_item *di;
2636         struct inode *inode = dentry->d_inode;
2637         u64 index;
2638         int check_link = 1;
2639         int err = -ENOSPC;
2640         int ret;
2641         u64 ino = btrfs_ino(inode);
2642         u64 dir_ino = btrfs_ino(dir);
2643
2644         /*
2645          * 1 for the possible orphan item
2646          * 1 for the dir item
2647          * 1 for the dir index
2648          * 1 for the inode ref
2649          * 1 for the inode ref in the tree log
2650          * 2 for the dir entries in the log
2651          * 1 for the inode
2652          */
2653         trans = btrfs_start_transaction(root, 8);
2654         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
2655                 return trans;
2656
2657         if (ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
2658                 return ERR_PTR(-ENOSPC);
2659
2660         /* check if there is someone else holds reference */
2661         if (S_ISDIR(inode->i_mode) && atomic_read(&inode->i_count) > 1)
2662                 return ERR_PTR(-ENOSPC);
2663
2664         if (atomic_read(&inode->i_count) > 2)
2665                 return ERR_PTR(-ENOSPC);
2666
2667         if (xchg(&root->fs_info->enospc_unlink, 1))
2668                 return ERR_PTR(-ENOSPC);
2669
2670         path = btrfs_alloc_path();
2671         if (!path) {
2672                 root->fs_info->enospc_unlink = 0;
2673                 return ERR_PTR(-ENOMEM);
2674         }
2675
2676         /* 1 for the orphan item */
2677         trans = btrfs_start_transaction(root, 1);
2678         if (IS_ERR(trans)) {
2679                 btrfs_free_path(path);
2680                 root->fs_info->enospc_unlink = 0;
2681                 return trans;
2682         }
2683
2684         path->skip_locking = 1;
2685         path->search_commit_root = 1;
2686
2687         ret = btrfs_lookup_inode(trans, root, path,
2688                                 &BTRFS_I(dir)->location, 0);
2689         if (ret < 0) {
2690                 err = ret;
2691                 goto out;
2692         }
2693         if (ret == 0) {
2694                 if (check_path_shared(root, path))
2695                         goto out;
2696         } else {
2697                 check_link = 0;
2698         }
2699         btrfs_release_path(path);
2700
2701         ret = btrfs_lookup_inode(trans, root, path,
2702                                 &BTRFS_I(inode)->location, 0);
2703         if (ret < 0) {
2704                 err = ret;
2705                 goto out;
2706         }
2707         if (ret == 0) {
2708                 if (check_path_shared(root, path))
2709                         goto out;
2710         } else {
2711                 check_link = 0;
2712         }
2713         btrfs_release_path(path);
2714
2715         if (ret == 0 && S_ISREG(inode->i_mode)) {
2716                 ret = btrfs_lookup_file_extent(trans, root, path,
2717                                                ino, (u64)-1, 0);
2718                 if (ret < 0) {
2719                         err = ret;
2720                         goto out;
2721                 }
2722                 BUG_ON(ret == 0);
2723                 if (check_path_shared(root, path))
2724                         goto out;
2725                 btrfs_release_path(path);
2726         }
2727
2728         if (!check_link) {
2729                 err = 0;
2730                 goto out;
2731         }
2732
2733         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2734                                 dentry->d_name.name, dentry->d_name.len, 0);
2735         if (IS_ERR(di)) {
2736                 err = PTR_ERR(di);
2737                 goto out;
2738         }
2739         if (di) {
2740                 if (check_path_shared(root, path))
2741                         goto out;
2742         } else {
2743                 err = 0;
2744                 goto out;
2745         }
2746         btrfs_release_path(path);
2747
2748         ref = btrfs_lookup_inode_ref(trans, root, path,
2749                                 dentry->d_name.name, dentry->d_name.len,
2750                                 ino, dir_ino, 0);
2751         if (IS_ERR(ref)) {
2752                 err = PTR_ERR(ref);
2753                 goto out;
2754         }
2755         BUG_ON(!ref);
2756         if (check_path_shared(root, path))
2757                 goto out;
2758         index = btrfs_inode_ref_index(path->nodes[0], ref);
2759         btrfs_release_path(path);
2760
2761         /*
2762          * This is a commit root search, if we can lookup inode item and other
2763          * relative items in the commit root, it means the transaction of
2764          * dir/file creation has been committed, and the dir index item that we
2765          * delay to insert has also been inserted into the commit root. So
2766          * we needn't worry about the delayed insertion of the dir index item
2767          * here.
2768          */
2769         di = btrfs_lookup_dir_index_item(trans, root, path, dir_ino, index,
2770                                 dentry->d_name.name, dentry->d_name.len, 0);
2771         if (IS_ERR(di)) {
2772                 err = PTR_ERR(di);
2773                 goto out;
2774         }
2775         BUG_ON(ret == -ENOENT);
2776         if (check_path_shared(root, path))
2777                 goto out;
2778
2779         err = 0;
2780 out:
2781         btrfs_free_path(path);
2782         /* Migrate the orphan reservation over */
2783         if (!err)
2784                 err = btrfs_block_rsv_migrate(trans->block_rsv,
2785                                 &root->fs_info->global_block_rsv,
2786                                 trans->bytes_reserved);
2787
2788         if (err) {
2789                 btrfs_end_transaction(trans, root);
2790                 root->fs_info->enospc_unlink = 0;
2791                 return ERR_PTR(err);
2792         }
2793
2794         trans->block_rsv = &root->fs_info->global_block_rsv;
2795         return trans;
2796 }
2797
2798 static void __unlink_end_trans(struct btrfs_trans_handle *trans,
2799                                struct btrfs_root *root)
2800 {
2801         if (trans->block_rsv == &root->fs_info->global_block_rsv) {
2802                 btrfs_block_rsv_release(root, trans->block_rsv,
2803                                         trans->bytes_reserved);
2804                 trans->block_rsv = &root->fs_info->trans_block_rsv;
2805                 BUG_ON(!root->fs_info->enospc_unlink);
2806                 root->fs_info->enospc_unlink = 0;
2807         }
2808         btrfs_end_transaction_throttle(trans, root);
2809 }
2810
2811 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
2812 {
2813         struct btrfs_root *root = BTRFS_I(dir)->root;
2814         struct btrfs_trans_handle *trans;
2815         struct inode *inode = dentry->d_inode;
2816         int ret;
2817         unsigned long nr = 0;
2818
2819         trans = __unlink_start_trans(dir, dentry);
2820         if (IS_ERR(trans))
2821                 return PTR_ERR(trans);
2822
2823         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
2824
2825         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
2826                                  dentry->d_name.name, dentry->d_name.len);
2827         if (ret)
2828                 goto out;
2829
2830         if (inode->i_nlink == 0) {
2831                 ret = btrfs_orphan_add(trans, inode);
2832                 if (ret)
2833                         goto out;
2834         }
2835
2836 out:
2837         nr = trans->blocks_used;
2838         __unlink_end_trans(trans, root);
2839         btrfs_btree_balance_dirty(root, nr);
2840         return ret;
2841 }
2842
2843 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
2844                         struct btrfs_root *root,
2845                         struct inode *dir, u64 objectid,
2846                         const char *name, int name_len)
2847 {
2848         struct btrfs_path *path;
2849         struct extent_buffer *leaf;
2850         struct btrfs_dir_item *di;
2851         struct btrfs_key key;
2852         u64 index;
2853         int ret;
2854         u64 dir_ino = btrfs_ino(dir);
2855
2856         path = btrfs_alloc_path();
2857         if (!path)
2858                 return -ENOMEM;
2859
2860         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2861                                    name, name_len, -1);
2862         BUG_ON(IS_ERR_OR_NULL(di));
2863
2864         leaf = path->nodes[0];
2865         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2866         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
2867         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2868         BUG_ON(ret);
2869         btrfs_release_path(path);
2870
2871         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
2872                                  objectid, root->root_key.objectid,
2873                                  dir_ino, &index, name, name_len);
2874         if (ret < 0) {
2875                 BUG_ON(ret != -ENOENT);
2876                 di = btrfs_search_dir_index_item(root, path, dir_ino,
2877                                                  name, name_len);
2878                 BUG_ON(IS_ERR_OR_NULL(di));
2879
2880                 leaf = path->nodes[0];
2881                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2882                 btrfs_release_path(path);
2883                 index = key.offset;
2884         }
2885         btrfs_release_path(path);
2886
2887         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
2888         BUG_ON(ret);
2889
2890         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2891         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2892         ret = btrfs_update_inode(trans, root, dir);
2893         BUG_ON(ret);
2894
2895         btrfs_free_path(path);
2896         return 0;
2897 }
2898
2899 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
2900 {
2901         struct inode *inode = dentry->d_inode;
2902         int err = 0;
2903         struct btrfs_root *root = BTRFS_I(dir)->root;
2904         struct btrfs_trans_handle *trans;
2905         unsigned long nr = 0;
2906
2907         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
2908             btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
2909                 return -ENOTEMPTY;
2910
2911         trans = __unlink_start_trans(dir, dentry);
2912         if (IS_ERR(trans))
2913                 return PTR_ERR(trans);
2914
2915         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
2916                 err = btrfs_unlink_subvol(trans, root, dir,
2917                                           BTRFS_I(inode)->location.objectid,
2918                                           dentry->d_name.name,
2919                                           dentry->d_name.len);
2920                 goto out;
2921         }
2922
2923         err = btrfs_orphan_add(trans, inode);
2924         if (err)
2925                 goto out;
2926
2927         /* now the directory is empty */
2928         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
2929                                  dentry->d_name.name, dentry->d_name.len);
2930         if (!err)
2931                 btrfs_i_size_write(inode, 0);
2932 out:
2933         nr = trans->blocks_used;
2934         __unlink_end_trans(trans, root);
2935         btrfs_btree_balance_dirty(root, nr);
2936
2937         return err;
2938 }
2939
2940 /*
2941  * this can truncate away extent items, csum items and directory items.
2942  * It starts at a high offset and removes keys until it can't find
2943  * any higher than new_size
2944  *
2945  * csum items that cross the new i_size are truncated to the new size
2946  * as well.
2947  *
2948  * min_type is the minimum key type to truncate down to.  If set to 0, this
2949  * will kill all the items on this inode, including the INODE_ITEM_KEY.
2950  */
2951 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
2952                                struct btrfs_root *root,
2953                                struct inode *inode,
2954                                u64 new_size, u32 min_type)
2955 {
2956         struct btrfs_path *path;
2957         struct extent_buffer *leaf;
2958         struct btrfs_file_extent_item *fi;
2959         struct btrfs_key key;
2960         struct btrfs_key found_key;
2961         u64 extent_start = 0;
2962         u64 extent_num_bytes = 0;
2963         u64 extent_offset = 0;
2964         u64 item_end = 0;
2965         u64 mask = root->sectorsize - 1;
2966         u32 found_type = (u8)-1;
2967         int found_extent;
2968         int del_item;
2969         int pending_del_nr = 0;
2970         int pending_del_slot = 0;
2971         int extent_type = -1;
2972         int encoding;
2973         int ret;
2974         int err = 0;
2975         u64 ino = btrfs_ino(inode);
2976
2977         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
2978
2979         path = btrfs_alloc_path();
2980         if (!path)
2981                 return -ENOMEM;
2982         path->reada = -1;
2983
2984         if (root->ref_cows || root == root->fs_info->tree_root)
2985                 btrfs_drop_extent_cache(inode, new_size & (~mask), (u64)-1, 0);
2986
2987         /*
2988          * This function is also used to drop the items in the log tree before
2989          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
2990          * it is used to drop the loged items. So we shouldn't kill the delayed
2991          * items.
2992          */
2993         if (min_type == 0 && root == BTRFS_I(inode)->root)
2994                 btrfs_kill_delayed_inode_items(inode);
2995
2996         key.objectid = ino;
2997         key.offset = (u64)-1;
2998         key.type = (u8)-1;
2999
3000 search_again:
3001         path->leave_spinning = 1;
3002         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3003         if (ret < 0) {
3004                 err = ret;
3005                 goto out;
3006         }
3007
3008         if (ret > 0) {
3009                 /* there are no items in the tree for us to truncate, we're
3010                  * done
3011                  */
3012                 if (path->slots[0] == 0)
3013                         goto out;
3014                 path->slots[0]--;
3015         }
3016
3017         while (1) {
3018                 fi = NULL;
3019                 leaf = path->nodes[0];
3020                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3021                 found_type = btrfs_key_type(&found_key);
3022                 encoding = 0;
3023
3024                 if (found_key.objectid != ino)
3025                         break;
3026
3027                 if (found_type < min_type)
3028                         break;
3029
3030                 item_end = found_key.offset;
3031                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
3032                         fi = btrfs_item_ptr(leaf, path->slots[0],
3033                                             struct btrfs_file_extent_item);
3034                         extent_type = btrfs_file_extent_type(leaf, fi);
3035                         encoding = btrfs_file_extent_compression(leaf, fi);
3036                         encoding |= btrfs_file_extent_encryption(leaf, fi);
3037                         encoding |= btrfs_file_extent_other_encoding(leaf, fi);
3038
3039                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3040                                 item_end +=
3041                                     btrfs_file_extent_num_bytes(leaf, fi);
3042                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3043                                 item_end += btrfs_file_extent_inline_len(leaf,
3044                                                                          fi);
3045                         }
3046                         item_end--;
3047                 }
3048                 if (found_type > min_type) {
3049                         del_item = 1;
3050                 } else {
3051                         if (item_end < new_size)
3052                                 break;
3053                         if (found_key.offset >= new_size)
3054                                 del_item = 1;
3055                         else
3056                                 del_item = 0;
3057                 }
3058                 found_extent = 0;
3059                 /* FIXME, shrink the extent if the ref count is only 1 */
3060                 if (found_type != BTRFS_EXTENT_DATA_KEY)
3061                         goto delete;
3062
3063                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3064                         u64 num_dec;
3065                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
3066                         if (!del_item && !encoding) {
3067                                 u64 orig_num_bytes =
3068                                         btrfs_file_extent_num_bytes(leaf, fi);
3069                                 extent_num_bytes = new_size -
3070                                         found_key.offset + root->sectorsize - 1;
3071                                 extent_num_bytes = extent_num_bytes &
3072                                         ~((u64)root->sectorsize - 1);
3073                                 btrfs_set_file_extent_num_bytes(leaf, fi,
3074                                                          extent_num_bytes);
3075                                 num_dec = (orig_num_bytes -
3076                                            extent_num_bytes);
3077                                 if (root->ref_cows && extent_start != 0)
3078                                         inode_sub_bytes(inode, num_dec);
3079                                 btrfs_mark_buffer_dirty(leaf);
3080                         } else {
3081                                 extent_num_bytes =
3082                                         btrfs_file_extent_disk_num_bytes(leaf,
3083                                                                          fi);
3084                                 extent_offset = found_key.offset -
3085                                         btrfs_file_extent_offset(leaf, fi);
3086
3087                                 /* FIXME blocksize != 4096 */
3088                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
3089                                 if (extent_start != 0) {
3090                                         found_extent = 1;
3091                                         if (root->ref_cows)
3092                                                 inode_sub_bytes(inode, num_dec);
3093                                 }
3094                         }
3095                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3096                         /*
3097                          * we can't truncate inline items that have had
3098                          * special encodings
3099                          */
3100                         if (!del_item &&
3101                             btrfs_file_extent_compression(leaf, fi) == 0 &&
3102                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
3103                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
3104                                 u32 size = new_size - found_key.offset;
3105
3106                                 if (root->ref_cows) {
3107                                         inode_sub_bytes(inode, item_end + 1 -
3108                                                         new_size);
3109                                 }
3110                                 size =
3111                                     btrfs_file_extent_calc_inline_size(size);
3112                                 ret = btrfs_truncate_item(trans, root, path,
3113                                                           size, 1);
3114                         } else if (root->ref_cows) {
3115                                 inode_sub_bytes(inode, item_end + 1 -
3116                                                 found_key.offset);
3117                         }
3118                 }
3119 delete:
3120                 if (del_item) {
3121                         if (!pending_del_nr) {
3122                                 /* no pending yet, add ourselves */
3123                                 pending_del_slot = path->slots[0];
3124                                 pending_del_nr = 1;
3125                         } else if (pending_del_nr &&
3126                                    path->slots[0] + 1 == pending_del_slot) {
3127                                 /* hop on the pending chunk */
3128                                 pending_del_nr++;
3129                                 pending_del_slot = path->slots[0];
3130                         } else {
3131                                 BUG();
3132                         }
3133                 } else {
3134                         break;
3135                 }
3136                 if (found_extent && (root->ref_cows ||
3137                                      root == root->fs_info->tree_root)) {
3138                         btrfs_set_path_blocking(path);
3139                         ret = btrfs_free_extent(trans, root, extent_start,
3140                                                 extent_num_bytes, 0,
3141                                                 btrfs_header_owner(leaf),
3142                                                 ino, extent_offset);
3143                         BUG_ON(ret);
3144                 }
3145
3146                 if (found_type == BTRFS_INODE_ITEM_KEY)
3147                         break;
3148
3149                 if (path->slots[0] == 0 ||
3150                     path->slots[0] != pending_del_slot) {
3151                         if (root->ref_cows &&
3152                             BTRFS_I(inode)->location.objectid !=
3153                                                 BTRFS_FREE_INO_OBJECTID) {
3154                                 err = -EAGAIN;
3155                                 goto out;
3156                         }
3157                         if (pending_del_nr) {
3158                                 ret = btrfs_del_items(trans, root, path,
3159                                                 pending_del_slot,
3160                                                 pending_del_nr);
3161                                 BUG_ON(ret);
3162                                 pending_del_nr = 0;
3163                         }
3164                         btrfs_release_path(path);
3165                         goto search_again;
3166                 } else {
3167                         path->slots[0]--;
3168                 }
3169         }
3170 out:
3171         if (pending_del_nr) {
3172                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
3173                                       pending_del_nr);
3174                 BUG_ON(ret);
3175         }
3176         btrfs_free_path(path);
3177         return err;
3178 }
3179
3180 /*
3181  * taken from block_truncate_page, but does cow as it zeros out
3182  * any bytes left in the last page in the file.
3183  */
3184 static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
3185 {
3186         struct inode *inode = mapping->host;
3187         struct btrfs_root *root = BTRFS_I(inode)->root;
3188         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3189         struct btrfs_ordered_extent *ordered;
3190         struct extent_state *cached_state = NULL;
3191         char *kaddr;
3192         u32 blocksize = root->sectorsize;
3193         pgoff_t index = from >> PAGE_CACHE_SHIFT;
3194         unsigned offset = from & (PAGE_CACHE_SIZE-1);
3195         struct page *page;
3196         gfp_t mask = btrfs_alloc_write_mask(mapping);
3197         int ret = 0;
3198         u64 page_start;
3199         u64 page_end;
3200
3201         if ((offset & (blocksize - 1)) == 0)
3202                 goto out;
3203         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
3204         if (ret)
3205                 goto out;
3206
3207         ret = -ENOMEM;
3208 again:
3209         page = find_or_create_page(mapping, index, mask);
3210         if (!page) {
3211                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3212                 goto out;
3213         }
3214
3215         page_start = page_offset(page);
3216         page_end = page_start + PAGE_CACHE_SIZE - 1;
3217
3218         if (!PageUptodate(page)) {
3219                 ret = btrfs_readpage(NULL, page);
3220                 lock_page(page);
3221                 if (page->mapping != mapping) {
3222                         unlock_page(page);
3223                         page_cache_release(page);
3224                         goto again;
3225                 }
3226                 if (!PageUptodate(page)) {
3227                         ret = -EIO;
3228                         goto out_unlock;
3229                 }
3230         }
3231         wait_on_page_writeback(page);
3232
3233         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state,
3234                          GFP_NOFS);
3235         set_page_extent_mapped(page);
3236
3237         ordered = btrfs_lookup_ordered_extent(inode, page_start);
3238         if (ordered) {
3239                 unlock_extent_cached(io_tree, page_start, page_end,
3240                                      &cached_state, GFP_NOFS);
3241                 unlock_page(page);
3242                 page_cache_release(page);
3243                 btrfs_start_ordered_extent(inode, ordered, 1);
3244                 btrfs_put_ordered_extent(ordered);
3245                 goto again;
3246         }
3247
3248         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
3249                           EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING,
3250                           0, 0, &cached_state, GFP_NOFS);
3251
3252         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
3253                                         &cached_state);
3254         if (ret) {
3255                 unlock_extent_cached(io_tree, page_start, page_end,
3256                                      &cached_state, GFP_NOFS);
3257                 goto out_unlock;
3258         }
3259
3260         ret = 0;
3261         if (offset != PAGE_CACHE_SIZE) {
3262                 kaddr = kmap(page);
3263                 memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
3264                 flush_dcache_page(page);
3265                 kunmap(page);
3266         }
3267         ClearPageChecked(page);
3268         set_page_dirty(page);
3269         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
3270                              GFP_NOFS);
3271
3272 out_unlock:
3273         if (ret)
3274                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3275         unlock_page(page);
3276         page_cache_release(page);
3277 out:
3278         return ret;
3279 }
3280
3281 /*
3282  * This function puts in dummy file extents for the area we're creating a hole
3283  * for.  So if we are truncating this file to a larger size we need to insert
3284  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
3285  * the range between oldsize and size
3286  */
3287 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
3288 {
3289         struct btrfs_trans_handle *trans;
3290         struct btrfs_root *root = BTRFS_I(inode)->root;
3291         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3292         struct extent_map *em = NULL;
3293         struct extent_state *cached_state = NULL;
3294         u64 mask = root->sectorsize - 1;
3295         u64 hole_start = (oldsize + mask) & ~mask;
3296         u64 block_end = (size + mask) & ~mask;
3297         u64 last_byte;
3298         u64 cur_offset;
3299         u64 hole_size;
3300         int err = 0;
3301
3302         if (size <= hole_start)
3303                 return 0;
3304
3305         while (1) {
3306                 struct btrfs_ordered_extent *ordered;
3307                 btrfs_wait_ordered_range(inode, hole_start,
3308                                          block_end - hole_start);
3309                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
3310                                  &cached_state, GFP_NOFS);
3311                 ordered = btrfs_lookup_ordered_extent(inode, hole_start);
3312                 if (!ordered)
3313                         break;
3314                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
3315                                      &cached_state, GFP_NOFS);
3316                 btrfs_put_ordered_extent(ordered);
3317         }
3318
3319         cur_offset = hole_start;
3320         while (1) {
3321                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
3322                                 block_end - cur_offset, 0);
3323                 BUG_ON(IS_ERR_OR_NULL(em));
3324                 last_byte = min(extent_map_end(em), block_end);
3325                 last_byte = (last_byte + mask) & ~mask;
3326                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
3327                         u64 hint_byte = 0;
3328                         hole_size = last_byte - cur_offset;
3329
3330                         trans = btrfs_start_transaction(root, 2);
3331                         if (IS_ERR(trans)) {
3332                                 err = PTR_ERR(trans);
3333                                 break;
3334                         }
3335
3336                         err = btrfs_drop_extents(trans, inode, cur_offset,
3337                                                  cur_offset + hole_size,
3338                                                  &hint_byte, 1);
3339                         if (err) {
3340                                 btrfs_end_transaction(trans, root);
3341                                 break;
3342                         }
3343
3344                         err = btrfs_insert_file_extent(trans, root,
3345                                         btrfs_ino(inode), cur_offset, 0,
3346                                         0, hole_size, 0, hole_size,
3347                                         0, 0, 0);
3348                         if (err) {
3349                                 btrfs_end_transaction(trans, root);
3350                                 break;
3351                         }
3352
3353                         btrfs_drop_extent_cache(inode, hole_start,
3354                                         last_byte - 1, 0);
3355
3356                         btrfs_end_transaction(trans, root);
3357                 }
3358                 free_extent_map(em);
3359                 em = NULL;
3360                 cur_offset = last_byte;
3361                 if (cur_offset >= block_end)
3362                         break;
3363         }
3364
3365         free_extent_map(em);
3366         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
3367                              GFP_NOFS);
3368         return err;
3369 }
3370
3371 static int btrfs_setsize(struct inode *inode, loff_t newsize)
3372 {
3373         loff_t oldsize = i_size_read(inode);
3374         int ret;
3375
3376         if (newsize == oldsize)
3377                 return 0;
3378
3379         if (newsize > oldsize) {
3380                 i_size_write(inode, newsize);
3381                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
3382                 truncate_pagecache(inode, oldsize, newsize);
3383                 ret = btrfs_cont_expand(inode, oldsize, newsize);
3384                 if (ret) {
3385                         btrfs_setsize(inode, oldsize);
3386                         return ret;
3387                 }
3388
3389                 mark_inode_dirty(inode);
3390         } else {
3391
3392                 /*
3393                  * We're truncating a file that used to have good data down to
3394                  * zero. Make sure it gets into the ordered flush list so that
3395                  * any new writes get down to disk quickly.
3396                  */
3397                 if (newsize == 0)
3398                         BTRFS_I(inode)->ordered_data_close = 1;
3399
3400                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
3401                 truncate_setsize(inode, newsize);
3402                 ret = btrfs_truncate(inode);
3403         }
3404
3405         return ret;
3406 }
3407
3408 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
3409 {
3410         struct inode *inode = dentry->d_inode;
3411         struct btrfs_root *root = BTRFS_I(inode)->root;
3412         int err;
3413
3414         if (btrfs_root_readonly(root))
3415                 return -EROFS;
3416
3417         err = inode_change_ok(inode, attr);
3418         if (err)
3419                 return err;
3420
3421         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
3422                 err = btrfs_setsize(inode, attr->ia_size);
3423                 if (err)
3424                         return err;
3425         }
3426
3427         if (attr->ia_valid) {
3428                 setattr_copy(inode, attr);
3429                 mark_inode_dirty(inode);
3430
3431                 if (attr->ia_valid & ATTR_MODE)
3432                         err = btrfs_acl_chmod(inode);
3433         }
3434
3435         return err;
3436 }
3437
3438 void btrfs_evict_inode(struct inode *inode)
3439 {
3440         struct btrfs_trans_handle *trans;
3441         struct btrfs_root *root = BTRFS_I(inode)->root;
3442         struct btrfs_block_rsv *rsv, *global_rsv;
3443         u64 min_size = btrfs_calc_trunc_metadata_size(root, 1);
3444         unsigned long nr;
3445         int ret;
3446
3447         trace_btrfs_inode_evict(inode);
3448
3449         truncate_inode_pages(&inode->i_data, 0);
3450         if (inode->i_nlink && (btrfs_root_refs(&root->root_item) != 0 ||
3451                                btrfs_is_free_space_inode(root, inode)))
3452                 goto no_delete;
3453
3454         if (is_bad_inode(inode)) {
3455                 btrfs_orphan_del(NULL, inode);
3456                 goto no_delete;
3457         }
3458         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
3459         btrfs_wait_ordered_range(inode, 0, (u64)-1);
3460
3461         if (root->fs_info->log_root_recovering) {
3462                 BUG_ON(!list_empty(&BTRFS_I(inode)->i_orphan));
3463                 goto no_delete;
3464         }
3465
3466         if (inode->i_nlink > 0) {
3467                 BUG_ON(btrfs_root_refs(&root->root_item) != 0);
3468                 goto no_delete;
3469         }
3470
3471         rsv = btrfs_alloc_block_rsv(root);
3472         if (!rsv) {
3473                 btrfs_orphan_del(NULL, inode);
3474                 goto no_delete;
3475         }
3476         rsv->size = min_size;
3477         global_rsv = &root->fs_info->global_block_rsv;
3478
3479         btrfs_i_size_write(inode, 0);
3480
3481         /*
3482          * This is a bit simpler than btrfs_truncate since
3483          *
3484          * 1) We've already reserved our space for our orphan item in the
3485          *    unlink.
3486          * 2) We're going to delete the inode item, so we don't need to update
3487          *    it at all.
3488          *
3489          * So we just need to reserve some slack space in case we add bytes when
3490          * doing the truncate.
3491          */
3492         while (1) {
3493                 ret = btrfs_block_rsv_refill(root, rsv, min_size);
3494
3495                 /*
3496                  * Try and steal from the global reserve since we will
3497                  * likely not use this space anyway, we want to try as
3498                  * hard as possible to get this to work.
3499                  */
3500                 if (ret)
3501                         ret = btrfs_block_rsv_migrate(global_rsv, rsv, min_size);
3502
3503                 if (ret) {
3504                         printk(KERN_WARNING "Could not get space for a "
3505                                "delete, will truncate on mount %d\n", ret);
3506                         btrfs_orphan_del(NULL, inode);
3507                         btrfs_free_block_rsv(root, rsv);
3508                         goto no_delete;
3509                 }
3510
3511                 trans = btrfs_start_transaction(root, 0);
3512                 if (IS_ERR(trans)) {
3513                         btrfs_orphan_del(NULL, inode);
3514                         btrfs_free_block_rsv(root, rsv);
3515                         goto no_delete;
3516                 }
3517
3518                 trans->block_rsv = rsv;
3519
3520                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
3521                 if (ret != -EAGAIN)
3522                         break;
3523
3524                 nr = trans->blocks_used;
3525                 btrfs_end_transaction(trans, root);
3526                 trans = NULL;
3527                 btrfs_btree_balance_dirty(root, nr);
3528         }
3529
3530         btrfs_free_block_rsv(root, rsv);
3531
3532         if (ret == 0) {
3533                 trans->block_rsv = root->orphan_block_rsv;
3534                 ret = btrfs_orphan_del(trans, inode);
3535                 BUG_ON(ret);
3536         }
3537
3538         trans->block_rsv = &root->fs_info->trans_block_rsv;
3539         if (!(root == root->fs_info->tree_root ||
3540               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
3541                 btrfs_return_ino(root, btrfs_ino(inode));
3542
3543         nr = trans->blocks_used;
3544         btrfs_end_transaction(trans, root);
3545         btrfs_btree_balance_dirty(root, nr);
3546 no_delete:
3547         end_writeback(inode);
3548         return;
3549 }
3550
3551 /*
3552  * this returns the key found in the dir entry in the location pointer.
3553  * If no dir entries were found, location->objectid is 0.
3554  */
3555 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
3556                                struct btrfs_key *location)
3557 {
3558         const char *name = dentry->d_name.name;
3559         int namelen = dentry->d_name.len;
3560         struct btrfs_dir_item *di;
3561         struct btrfs_path *path;
3562         struct btrfs_root *root = BTRFS_I(dir)->root;
3563         int ret = 0;
3564
3565         path = btrfs_alloc_path();
3566         if (!path)
3567                 return -ENOMEM;
3568
3569         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
3570                                     namelen, 0);
3571         if (IS_ERR(di))
3572                 ret = PTR_ERR(di);
3573
3574         if (IS_ERR_OR_NULL(di))
3575                 goto out_err;
3576
3577         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
3578 out:
3579         btrfs_free_path(path);
3580         return ret;
3581 out_err:
3582         location->objectid = 0;
3583         goto out;
3584 }
3585
3586 /*
3587  * when we hit a tree root in a directory, the btrfs part of the inode
3588  * needs to be changed to reflect the root directory of the tree root.  This
3589  * is kind of like crossing a mount point.
3590  */
3591 static int fixup_tree_root_location(struct btrfs_root *root,
3592                                     struct inode *dir,
3593                                     struct dentry *dentry,
3594                                     struct btrfs_key *location,
3595                                     struct btrfs_root **sub_root)
3596 {
3597         struct btrfs_path *path;
3598         struct btrfs_root *new_root;
3599         struct btrfs_root_ref *ref;
3600         struct extent_buffer *leaf;
3601         int ret;
3602         int err = 0;
3603
3604         path = btrfs_alloc_path();
3605         if (!path) {
3606                 err = -ENOMEM;
3607                 goto out;
3608         }
3609
3610         err = -ENOENT;
3611         ret = btrfs_find_root_ref(root->fs_info->tree_root, path,
3612                                   BTRFS_I(dir)->root->root_key.objectid,
3613                                   location->objectid);
3614         if (ret) {
3615                 if (ret < 0)
3616                         err = ret;
3617                 goto out;
3618         }
3619
3620         leaf = path->nodes[0];
3621         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
3622         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
3623             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
3624                 goto out;
3625
3626         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
3627                                    (unsigned long)(ref + 1),
3628                                    dentry->d_name.len);
3629         if (ret)
3630                 goto out;
3631
3632         btrfs_release_path(path);
3633
3634         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
3635         if (IS_ERR(new_root)) {
3636                 err = PTR_ERR(new_root);
3637                 goto out;
3638         }
3639
3640         if (btrfs_root_refs(&new_root->root_item) == 0) {
3641                 err = -ENOENT;
3642                 goto out;
3643         }
3644
3645         *sub_root = new_root;
3646         location->objectid = btrfs_root_dirid(&new_root->root_item);
3647         location->type = BTRFS_INODE_ITEM_KEY;
3648         location->offset = 0;
3649         err = 0;
3650 out:
3651         btrfs_free_path(path);
3652         return err;
3653 }
3654
3655 static void inode_tree_add(struct inode *inode)
3656 {
3657         struct btrfs_root *root = BTRFS_I(inode)->root;
3658         struct btrfs_inode *entry;
3659         struct rb_node **p;
3660         struct rb_node *parent;
3661         u64 ino = btrfs_ino(inode);
3662 again:
3663         p = &root->inode_tree.rb_node;
3664         parent = NULL;
3665
3666         if (inode_unhashed(inode))
3667                 return;
3668
3669         spin_lock(&root->inode_lock);
3670         while (*p) {
3671                 parent = *p;
3672                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
3673
3674                 if (ino < btrfs_ino(&entry->vfs_inode))
3675                         p = &parent->rb_left;
3676                 else if (ino > btrfs_ino(&entry->vfs_inode))
3677                         p = &parent->rb_right;
3678                 else {
3679                         WARN_ON(!(entry->vfs_inode.i_state &
3680                                   (I_WILL_FREE | I_FREEING)));
3681                         rb_erase(parent, &root->inode_tree);
3682                         RB_CLEAR_NODE(parent);
3683                         spin_unlock(&root->inode_lock);
3684                         goto again;
3685                 }
3686         }
3687         rb_link_node(&BTRFS_I(inode)->rb_node, parent, p);
3688         rb_insert_color(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3689         spin_unlock(&root->inode_lock);
3690 }
3691
3692 static void inode_tree_del(struct inode *inode)
3693 {
3694         struct btrfs_root *root = BTRFS_I(inode)->root;
3695         int empty = 0;
3696
3697         spin_lock(&root->inode_lock);
3698         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
3699                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3700                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
3701                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3702         }
3703         spin_unlock(&root->inode_lock);
3704
3705         /*
3706          * Free space cache has inodes in the tree root, but the tree root has a
3707          * root_refs of 0, so this could end up dropping the tree root as a
3708          * snapshot, so we need the extra !root->fs_info->tree_root check to
3709          * make sure we don't drop it.
3710          */
3711         if (empty && btrfs_root_refs(&root->root_item) == 0 &&
3712             root != root->fs_info->tree_root) {
3713                 synchronize_srcu(&root->fs_info->subvol_srcu);
3714                 spin_lock(&root->inode_lock);
3715                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3716                 spin_unlock(&root->inode_lock);
3717                 if (empty)
3718                         btrfs_add_dead_root(root);
3719         }
3720 }
3721
3722 int btrfs_invalidate_inodes(struct btrfs_root *root)
3723 {
3724         struct rb_node *node;
3725         struct rb_node *prev;
3726         struct btrfs_inode *entry;
3727         struct inode *inode;
3728         u64 objectid = 0;
3729
3730         WARN_ON(btrfs_root_refs(&root->root_item) != 0);
3731
3732         spin_lock(&root->inode_lock);
3733 again:
3734         node = root->inode_tree.rb_node;
3735         prev = NULL;
3736         while (node) {
3737                 prev = node;
3738                 entry = rb_entry(node, struct btrfs_inode, rb_node);
3739
3740                 if (objectid < btrfs_ino(&entry->vfs_inode))
3741                         node = node->rb_left;
3742                 else if (objectid > btrfs_ino(&entry->vfs_inode))
3743                         node = node->rb_right;
3744                 else
3745                         break;
3746         }
3747         if (!node) {
3748                 while (prev) {
3749                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
3750                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
3751                                 node = prev;
3752                                 break;
3753                         }
3754                         prev = rb_next(prev);
3755                 }
3756         }
3757         while (node) {
3758                 entry = rb_entry(node, struct btrfs_inode, rb_node);
3759                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
3760                 inode = igrab(&entry->vfs_inode);
3761                 if (inode) {
3762                         spin_unlock(&root->inode_lock);
3763                         if (atomic_read(&inode->i_count) > 1)
3764                                 d_prune_aliases(inode);
3765                         /*
3766                          * btrfs_drop_inode will have it removed from
3767                          * the inode cache when its usage count
3768                          * hits zero.
3769                          */
3770                         iput(inode);
3771                         cond_resched();
3772                         spin_lock(&root->inode_lock);
3773                         goto again;
3774                 }
3775
3776                 if (cond_resched_lock(&root->inode_lock))
3777                         goto again;
3778
3779                 node = rb_next(node);
3780         }
3781         spin_unlock(&root->inode_lock);
3782         return 0;
3783 }
3784
3785 static int btrfs_init_locked_inode(struct inode *inode, void *p)
3786 {
3787         struct btrfs_iget_args *args = p;
3788         inode->i_ino = args->ino;
3789         BTRFS_I(inode)->root = args->root;
3790         btrfs_set_inode_space_info(args->root, inode);
3791         return 0;
3792 }
3793
3794 static int btrfs_find_actor(struct inode *inode, void *opaque)
3795 {
3796         struct btrfs_iget_args *args = opaque;
3797         return args->ino == btrfs_ino(inode) &&
3798                 args->root == BTRFS_I(inode)->root;
3799 }
3800
3801 static struct inode *btrfs_iget_locked(struct super_block *s,
3802                                        u64 objectid,
3803                                        struct btrfs_root *root)
3804 {
3805         struct inode *inode;
3806         struct btrfs_iget_args args;
3807         args.ino = objectid;
3808         args.root = root;
3809
3810         inode = iget5_locked(s, objectid, btrfs_find_actor,
3811                              btrfs_init_locked_inode,
3812                              (void *)&args);
3813         return inode;
3814 }
3815
3816 /* Get an inode object given its location and corresponding root.
3817  * Returns in *is_new if the inode was read from disk
3818  */
3819 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
3820                          struct btrfs_root *root, int *new)
3821 {
3822         struct inode *inode;
3823
3824         inode = btrfs_iget_locked(s, location->objectid, root);
3825         if (!inode)
3826                 return ERR_PTR(-ENOMEM);
3827
3828         if (inode->i_state & I_NEW) {
3829                 BTRFS_I(inode)->root = root;
3830                 memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
3831                 btrfs_read_locked_inode(inode);
3832                 if (!is_bad_inode(inode)) {
3833                         inode_tree_add(inode);
3834                         unlock_new_inode(inode);
3835                         if (new)
3836                                 *new = 1;
3837                 } else {
3838                         unlock_new_inode(inode);
3839                         iput(inode);
3840                         inode = ERR_PTR(-ESTALE);
3841                 }
3842         }
3843
3844         return inode;
3845 }
3846
3847 static struct inode *new_simple_dir(struct super_block *s,
3848                                     struct btrfs_key *key,
3849                                     struct btrfs_root *root)
3850 {
3851         struct inode *inode = new_inode(s);
3852
3853         if (!inode)
3854                 return ERR_PTR(-ENOMEM);
3855
3856         BTRFS_I(inode)->root = root;
3857         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
3858         BTRFS_I(inode)->dummy_inode = 1;
3859
3860         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
3861         inode->i_op = &simple_dir_inode_operations;
3862         inode->i_fop = &simple_dir_operations;
3863         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
3864         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
3865
3866         return inode;
3867 }
3868
3869 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
3870 {
3871         struct inode *inode;
3872         struct btrfs_root *root = BTRFS_I(dir)->root;
3873         struct btrfs_root *sub_root = root;
3874         struct btrfs_key location;
3875         int index;
3876         int ret = 0;
3877
3878         if (dentry->d_name.len > BTRFS_NAME_LEN)
3879                 return ERR_PTR(-ENAMETOOLONG);
3880
3881         if (unlikely(d_need_lookup(dentry))) {
3882                 memcpy(&location, dentry->d_fsdata, sizeof(struct btrfs_key));
3883                 kfree(dentry->d_fsdata);
3884                 dentry->d_fsdata = NULL;
3885                 /* This thing is hashed, drop it for now */
3886                 d_drop(dentry);
3887         } else {
3888                 ret = btrfs_inode_by_name(dir, dentry, &location);
3889         }
3890
3891         if (ret < 0)
3892                 return ERR_PTR(ret);
3893
3894         if (location.objectid == 0)
3895                 return NULL;
3896
3897         if (location.type == BTRFS_INODE_ITEM_KEY) {
3898                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
3899                 return inode;
3900         }
3901
3902         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
3903
3904         index = srcu_read_lock(&root->fs_info->subvol_srcu);
3905         ret = fixup_tree_root_location(root, dir, dentry,
3906                                        &location, &sub_root);
3907         if (ret < 0) {
3908                 if (ret != -ENOENT)
3909                         inode = ERR_PTR(ret);
3910                 else
3911                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
3912         } else {
3913                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
3914         }
3915         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
3916
3917         if (!IS_ERR(inode) && root != sub_root) {
3918                 down_read(&root->fs_info->cleanup_work_sem);
3919                 if (!(inode->i_sb->s_flags & MS_RDONLY))
3920                         ret = btrfs_orphan_cleanup(sub_root);
3921                 up_read(&root->fs_info->cleanup_work_sem);
3922                 if (ret)
3923                         inode = ERR_PTR(ret);
3924         }
3925
3926         return inode;
3927 }
3928
3929 static int btrfs_dentry_delete(const struct dentry *dentry)
3930 {
3931         struct btrfs_root *root;
3932
3933         if (!dentry->d_inode && !IS_ROOT(dentry))
3934                 dentry = dentry->d_parent;
3935
3936         if (dentry->d_inode) {
3937                 root = BTRFS_I(dentry->d_inode)->root;
3938                 if (btrfs_root_refs(&root->root_item) == 0)
3939                         return 1;
3940         }
3941         return 0;
3942 }
3943
3944 static void btrfs_dentry_release(struct dentry *dentry)
3945 {
3946         if (dentry->d_fsdata)
3947                 kfree(dentry->d_fsdata);
3948 }
3949
3950 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
3951                                    struct nameidata *nd)
3952 {
3953         struct dentry *ret;
3954
3955         ret = d_splice_alias(btrfs_lookup_dentry(dir, dentry), dentry);
3956         if (unlikely(d_need_lookup(dentry))) {
3957                 spin_lock(&dentry->d_lock);
3958                 dentry->d_flags &= ~DCACHE_NEED_LOOKUP;
3959                 spin_unlock(&dentry->d_lock);
3960         }
3961         return ret;
3962 }
3963
3964 unsigned char btrfs_filetype_table[] = {
3965         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
3966 };
3967
3968 static int btrfs_real_readdir(struct file *filp, void *dirent,
3969                               filldir_t filldir)
3970 {
3971         struct inode *inode = filp->f_dentry->d_inode;
3972         struct btrfs_root *root = BTRFS_I(inode)->root;
3973         struct btrfs_item *item;
3974         struct btrfs_dir_item *di;
3975         struct btrfs_key key;
3976         struct btrfs_key found_key;
3977         struct btrfs_path *path;
3978         struct list_head ins_list;
3979         struct list_head del_list;
3980         struct qstr q;
3981         int ret;
3982         struct extent_buffer *leaf;
3983         int slot;
3984         unsigned char d_type;
3985         int over = 0;
3986         u32 di_cur;
3987         u32 di_total;
3988         u32 di_len;
3989         int key_type = BTRFS_DIR_INDEX_KEY;
3990         char tmp_name[32];
3991         char *name_ptr;
3992         int name_len;
3993         int is_curr = 0;        /* filp->f_pos points to the current index? */
3994
3995         /* FIXME, use a real flag for deciding about the key type */
3996         if (root->fs_info->tree_root == root)
3997                 key_type = BTRFS_DIR_ITEM_KEY;
3998
3999         /* special case for "." */
4000         if (filp->f_pos == 0) {
4001                 over = filldir(dirent, ".", 1,
4002                                filp->f_pos, btrfs_ino(inode), DT_DIR);
4003                 if (over)
4004                         return 0;
4005                 filp->f_pos = 1;
4006         }
4007         /* special case for .., just use the back ref */
4008         if (filp->f_pos == 1) {
4009                 u64 pino = parent_ino(filp->f_path.dentry);
4010                 over = filldir(dirent, "..", 2,
4011                                filp->f_pos, pino, DT_DIR);
4012                 if (over)
4013                         return 0;
4014                 filp->f_pos = 2;
4015         }
4016         path = btrfs_alloc_path();
4017         if (!path)
4018                 return -ENOMEM;
4019
4020         path->reada = 1;
4021
4022         if (key_type == BTRFS_DIR_INDEX_KEY) {
4023                 INIT_LIST_HEAD(&ins_list);
4024                 INIT_LIST_HEAD(&del_list);
4025                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
4026         }
4027
4028         btrfs_set_key_type(&key, key_type);
4029         key.offset = filp->f_pos;
4030         key.objectid = btrfs_ino(inode);
4031
4032         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4033         if (ret < 0)
4034                 goto err;
4035
4036         while (1) {
4037                 leaf = path->nodes[0];
4038                 slot = path->slots[0];
4039                 if (slot >= btrfs_header_nritems(leaf)) {
4040                         ret = btrfs_next_leaf(root, path);
4041                         if (ret < 0)
4042                                 goto err;
4043                         else if (ret > 0)
4044                                 break;
4045                         continue;
4046                 }
4047
4048                 item = btrfs_item_nr(leaf, slot);
4049                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
4050
4051                 if (found_key.objectid != key.objectid)
4052                         break;
4053                 if (btrfs_key_type(&found_key) != key_type)
4054                         break;
4055                 if (found_key.offset < filp->f_pos)
4056                         goto next;
4057                 if (key_type == BTRFS_DIR_INDEX_KEY &&
4058                     btrfs_should_delete_dir_index(&del_list,
4059                                                   found_key.offset))
4060                         goto next;
4061
4062                 filp->f_pos = found_key.offset;
4063                 is_curr = 1;
4064
4065                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
4066                 di_cur = 0;
4067                 di_total = btrfs_item_size(leaf, item);
4068
4069                 while (di_cur < di_total) {
4070                         struct btrfs_key location;
4071                         struct dentry *tmp;
4072
4073                         if (verify_dir_item(root, leaf, di))
4074                                 break;
4075
4076                         name_len = btrfs_dir_name_len(leaf, di);
4077                         if (name_len <= sizeof(tmp_name)) {
4078                                 name_ptr = tmp_name;
4079                         } else {
4080                                 name_ptr = kmalloc(name_len, GFP_NOFS);
4081                                 if (!name_ptr) {
4082                                         ret = -ENOMEM;
4083                                         goto err;
4084                                 }
4085                         }
4086                         read_extent_buffer(leaf, name_ptr,
4087                                            (unsigned long)(di + 1), name_len);
4088
4089                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
4090                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
4091
4092                         q.name = name_ptr;
4093                         q.len = name_len;
4094                         q.hash = full_name_hash(q.name, q.len);
4095                         tmp = d_lookup(filp->f_dentry, &q);
4096                         if (!tmp) {
4097                                 struct btrfs_key *newkey;
4098
4099                                 newkey = kzalloc(sizeof(struct btrfs_key),
4100                                                  GFP_NOFS);
4101                                 if (!newkey)
4102                                         goto no_dentry;
4103                                 tmp = d_alloc(filp->f_dentry, &q);
4104                                 if (!tmp) {
4105                                         kfree(newkey);
4106                                         dput(tmp);
4107                                         goto no_dentry;
4108                                 }
4109                                 memcpy(newkey, &location,
4110                                        sizeof(struct btrfs_key));
4111                                 tmp->d_fsdata = newkey;
4112                                 tmp->d_flags |= DCACHE_NEED_LOOKUP;
4113                                 d_rehash(tmp);
4114                                 dput(tmp);
4115                         } else {
4116                                 dput(tmp);
4117                         }
4118 no_dentry:
4119                         /* is this a reference to our own snapshot? If so
4120                          * skip it
4121                          */
4122                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
4123                             location.objectid == root->root_key.objectid) {
4124                                 over = 0;
4125                                 goto skip;
4126                         }
4127                         over = filldir(dirent, name_ptr, name_len,
4128                                        found_key.offset, location.objectid,
4129                                        d_type);
4130
4131 skip:
4132                         if (name_ptr != tmp_name)
4133                                 kfree(name_ptr);
4134
4135                         if (over)
4136                                 goto nopos;
4137                         di_len = btrfs_dir_name_len(leaf, di) +
4138                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
4139                         di_cur += di_len;
4140                         di = (struct btrfs_dir_item *)((char *)di + di_len);
4141                 }
4142 next:
4143                 path->slots[0]++;
4144         }
4145
4146         if (key_type == BTRFS_DIR_INDEX_KEY) {
4147                 if (is_curr)
4148                         filp->f_pos++;
4149                 ret = btrfs_readdir_delayed_dir_index(filp, dirent, filldir,
4150                                                       &ins_list);
4151                 if (ret)
4152                         goto nopos;
4153         }
4154
4155         /* Reached end of directory/root. Bump pos past the last item. */
4156         if (key_type == BTRFS_DIR_INDEX_KEY)
4157                 /*
4158                  * 32-bit glibc will use getdents64, but then strtol -
4159                  * so the last number we can serve is this.
4160                  */
4161                 filp->f_pos = 0x7fffffff;
4162         else
4163                 filp->f_pos++;
4164 nopos:
4165         ret = 0;
4166 err:
4167         if (key_type == BTRFS_DIR_INDEX_KEY)
4168                 btrfs_put_delayed_items(&ins_list, &del_list);
4169         btrfs_free_path(path);
4170         return ret;
4171 }
4172
4173 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
4174 {
4175         struct btrfs_root *root = BTRFS_I(inode)->root;
4176         struct btrfs_trans_handle *trans;
4177         int ret = 0;
4178         bool nolock = false;
4179
4180         if (BTRFS_I(inode)->dummy_inode)
4181                 return 0;
4182
4183         if (btrfs_fs_closing(root->fs_info) && btrfs_is_free_space_inode(root, inode))
4184                 nolock = true;
4185
4186         if (wbc->sync_mode == WB_SYNC_ALL) {
4187                 if (nolock)
4188                         trans = btrfs_join_transaction_nolock(root);
4189                 else
4190                         trans = btrfs_join_transaction(root);
4191                 if (IS_ERR(trans))
4192                         return PTR_ERR(trans);
4193                 if (nolock)
4194                         ret = btrfs_end_transaction_nolock(trans, root);
4195                 else
4196                         ret = btrfs_commit_transaction(trans, root);
4197         }
4198         return ret;
4199 }
4200
4201 /*
4202  * This is somewhat expensive, updating the tree every time the
4203  * inode changes.  But, it is most likely to find the inode in cache.
4204  * FIXME, needs more benchmarking...there are no reasons other than performance
4205  * to keep or drop this code.
4206  */
4207 void btrfs_dirty_inode(struct inode *inode, int flags)
4208 {
4209         struct btrfs_root *root = BTRFS_I(inode)->root;
4210         struct btrfs_trans_handle *trans;
4211         int ret;
4212
4213         if (BTRFS_I(inode)->dummy_inode)
4214                 return;
4215
4216         trans = btrfs_join_transaction(root);
4217         BUG_ON(IS_ERR(trans));
4218
4219         ret = btrfs_update_inode(trans, root, inode);
4220         if (ret && ret == -ENOSPC) {
4221                 /* whoops, lets try again with the full transaction */
4222                 btrfs_end_transaction(trans, root);
4223                 trans = btrfs_start_transaction(root, 1);
4224                 if (IS_ERR(trans)) {
4225                         printk_ratelimited(KERN_ERR "btrfs: fail to "
4226                                        "dirty  inode %llu error %ld\n",
4227                                        (unsigned long long)btrfs_ino(inode),
4228                                        PTR_ERR(trans));
4229                         return;
4230                 }
4231
4232                 ret = btrfs_update_inode(trans, root, inode);
4233                 if (ret) {
4234                         printk_ratelimited(KERN_ERR "btrfs: fail to "
4235                                        "dirty  inode %llu error %d\n",
4236                                        (unsigned long long)btrfs_ino(inode),
4237                                        ret);
4238                 }
4239         }
4240         btrfs_end_transaction(trans, root);
4241         if (BTRFS_I(inode)->delayed_node)
4242                 btrfs_balance_delayed_items(root);
4243 }
4244
4245 /*
4246  * find the highest existing sequence number in a directory
4247  * and then set the in-memory index_cnt variable to reflect
4248  * free sequence numbers
4249  */
4250 static int btrfs_set_inode_index_count(struct inode *inode)
4251 {
4252         struct btrfs_root *root = BTRFS_I(inode)->root;
4253         struct btrfs_key key, found_key;
4254         struct btrfs_path *path;
4255         struct extent_buffer *leaf;
4256         int ret;
4257
4258         key.objectid = btrfs_ino(inode);
4259         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
4260         key.offset = (u64)-1;
4261
4262         path = btrfs_alloc_path();
4263         if (!path)
4264                 return -ENOMEM;
4265
4266         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4267         if (ret < 0)
4268                 goto out;
4269         /* FIXME: we should be able to handle this */
4270         if (ret == 0)
4271                 goto out;
4272         ret = 0;
4273
4274         /*
4275          * MAGIC NUMBER EXPLANATION:
4276          * since we search a directory based on f_pos we have to start at 2
4277          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
4278          * else has to start at 2
4279          */
4280         if (path->slots[0] == 0) {
4281                 BTRFS_I(inode)->index_cnt = 2;
4282                 goto out;
4283         }
4284
4285         path->slots[0]--;
4286
4287         leaf = path->nodes[0];
4288         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4289
4290         if (found_key.objectid != btrfs_ino(inode) ||
4291             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
4292                 BTRFS_I(inode)->index_cnt = 2;
4293                 goto out;
4294         }
4295
4296         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
4297 out:
4298         btrfs_free_path(path);
4299         return ret;
4300 }
4301
4302 /*
4303  * helper to find a free sequence number in a given directory.  This current
4304  * code is very simple, later versions will do smarter things in the btree
4305  */
4306 int btrfs_set_inode_index(struct inode *dir, u64 *index)
4307 {
4308         int ret = 0;
4309
4310         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
4311                 ret = btrfs_inode_delayed_dir_index_count(dir);
4312                 if (ret) {
4313                         ret = btrfs_set_inode_index_count(dir);
4314                         if (ret)
4315                                 return ret;
4316                 }
4317         }
4318
4319         *index = BTRFS_I(dir)->index_cnt;
4320         BTRFS_I(dir)->index_cnt++;
4321
4322         return ret;
4323 }
4324
4325 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
4326                                      struct btrfs_root *root,
4327                                      struct inode *dir,
4328                                      const char *name, int name_len,
4329                                      u64 ref_objectid, u64 objectid, int mode,
4330                                      u64 *index)
4331 {
4332         struct inode *inode;
4333         struct btrfs_inode_item *inode_item;
4334         struct btrfs_key *location;
4335         struct btrfs_path *path;
4336         struct btrfs_inode_ref *ref;
4337         struct btrfs_key key[2];
4338         u32 sizes[2];
4339         unsigned long ptr;
4340         int ret;
4341         int owner;
4342
4343         path = btrfs_alloc_path();
4344         if (!path)
4345                 return ERR_PTR(-ENOMEM);
4346
4347         inode = new_inode(root->fs_info->sb);
4348         if (!inode) {
4349                 btrfs_free_path(path);
4350                 return ERR_PTR(-ENOMEM);
4351         }
4352
4353         /*
4354          * we have to initialize this early, so we can reclaim the inode
4355          * number if we fail afterwards in this function.
4356          */
4357         inode->i_ino = objectid;
4358
4359         if (dir) {
4360                 trace_btrfs_inode_request(dir);
4361
4362                 ret = btrfs_set_inode_index(dir, index);
4363                 if (ret) {
4364                         btrfs_free_path(path);
4365                         iput(inode);
4366                         return ERR_PTR(ret);
4367                 }
4368         }
4369         /*
4370          * index_cnt is ignored for everything but a dir,
4371          * btrfs_get_inode_index_count has an explanation for the magic
4372          * number
4373          */
4374         BTRFS_I(inode)->index_cnt = 2;
4375         BTRFS_I(inode)->root = root;
4376         BTRFS_I(inode)->generation = trans->transid;
4377         inode->i_generation = BTRFS_I(inode)->generation;
4378         btrfs_set_inode_space_info(root, inode);
4379
4380         if (S_ISDIR(mode))
4381                 owner = 0;
4382         else
4383                 owner = 1;
4384
4385         key[0].objectid = objectid;
4386         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
4387         key[0].offset = 0;
4388
4389         key[1].objectid = objectid;
4390         btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
4391         key[1].offset = ref_objectid;
4392
4393         sizes[0] = sizeof(struct btrfs_inode_item);
4394         sizes[1] = name_len + sizeof(*ref);
4395
4396         path->leave_spinning = 1;
4397         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
4398         if (ret != 0)
4399                 goto fail;
4400
4401         inode_init_owner(inode, dir, mode);
4402         inode_set_bytes(inode, 0);
4403         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
4404         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
4405                                   struct btrfs_inode_item);
4406         fill_inode_item(trans, path->nodes[0], inode_item, inode);
4407
4408         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
4409                              struct btrfs_inode_ref);
4410         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
4411         btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
4412         ptr = (unsigned long)(ref + 1);
4413         write_extent_buffer(path->nodes[0], name, ptr, name_len);
4414
4415         btrfs_mark_buffer_dirty(path->nodes[0]);
4416         btrfs_free_path(path);
4417
4418         location = &BTRFS_I(inode)->location;
4419         location->objectid = objectid;
4420         location->offset = 0;
4421         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
4422
4423         btrfs_inherit_iflags(inode, dir);
4424
4425         if (S_ISREG(mode)) {
4426                 if (btrfs_test_opt(root, NODATASUM))
4427                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
4428                 if (btrfs_test_opt(root, NODATACOW) ||
4429                     (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW))
4430                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
4431         }
4432
4433         insert_inode_hash(inode);
4434         inode_tree_add(inode);
4435
4436         trace_btrfs_inode_new(inode);
4437         btrfs_set_inode_last_trans(trans, inode);
4438
4439         return inode;
4440 fail:
4441         if (dir)
4442                 BTRFS_I(dir)->index_cnt--;
4443         btrfs_free_path(path);
4444         iput(inode);
4445         return ERR_PTR(ret);
4446 }
4447
4448 static inline u8 btrfs_inode_type(struct inode *inode)
4449 {
4450         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
4451 }
4452
4453 /*
4454  * utility function to add 'inode' into 'parent_inode' with
4455  * a give name and a given sequence number.
4456  * if 'add_backref' is true, also insert a backref from the
4457  * inode to the parent directory.
4458  */
4459 int btrfs_add_link(struct btrfs_trans_handle *trans,
4460                    struct inode *parent_inode, struct inode *inode,
4461                    const char *name, int name_len, int add_backref, u64 index)
4462 {
4463         int ret = 0;
4464         struct btrfs_key key;
4465         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
4466         u64 ino = btrfs_ino(inode);
4467         u64 parent_ino = btrfs_ino(parent_inode);
4468
4469         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4470                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
4471         } else {
4472                 key.objectid = ino;
4473                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
4474                 key.offset = 0;
4475         }
4476
4477         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4478                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
4479                                          key.objectid, root->root_key.objectid,
4480                                          parent_ino, index, name, name_len);
4481         } else if (add_backref) {
4482                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
4483                                              parent_ino, index);
4484         }
4485
4486         if (ret == 0) {
4487                 ret = btrfs_insert_dir_item(trans, root, name, name_len,
4488                                             parent_inode, &key,
4489                                             btrfs_inode_type(inode), index);
4490                 BUG_ON(ret);
4491
4492                 btrfs_i_size_write(parent_inode, parent_inode->i_size +
4493                                    name_len * 2);
4494                 parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
4495                 ret = btrfs_update_inode(trans, root, parent_inode);
4496         }
4497         return ret;
4498 }
4499
4500 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
4501                             struct inode *dir, struct dentry *dentry,
4502                             struct inode *inode, int backref, u64 index)
4503 {
4504         int err = btrfs_add_link(trans, dir, inode,
4505                                  dentry->d_name.name, dentry->d_name.len,
4506                                  backref, index);
4507         if (!err) {
4508                 d_instantiate(dentry, inode);
4509                 return 0;
4510         }
4511         if (err > 0)
4512                 err = -EEXIST;
4513         return err;
4514 }
4515
4516 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
4517                         int mode, dev_t rdev)
4518 {
4519         struct btrfs_trans_handle *trans;
4520         struct btrfs_root *root = BTRFS_I(dir)->root;
4521         struct inode *inode = NULL;
4522         int err;
4523         int drop_inode = 0;
4524         u64 objectid;
4525         unsigned long nr = 0;
4526         u64 index = 0;
4527
4528         if (!new_valid_dev(rdev))
4529                 return -EINVAL;
4530
4531         /*
4532          * 2 for inode item and ref
4533          * 2 for dir items
4534          * 1 for xattr if selinux is on
4535          */
4536         trans = btrfs_start_transaction(root, 5);
4537         if (IS_ERR(trans))
4538                 return PTR_ERR(trans);
4539
4540         err = btrfs_find_free_ino(root, &objectid);
4541         if (err)
4542                 goto out_unlock;
4543
4544         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4545                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4546                                 mode, &index);
4547         if (IS_ERR(inode)) {
4548                 err = PTR_ERR(inode);
4549                 goto out_unlock;
4550         }
4551
4552         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4553         if (err) {
4554                 drop_inode = 1;
4555                 goto out_unlock;
4556         }
4557
4558         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4559         if (err)
4560                 drop_inode = 1;
4561         else {
4562                 inode->i_op = &btrfs_special_inode_operations;
4563                 init_special_inode(inode, inode->i_mode, rdev);
4564                 btrfs_update_inode(trans, root, inode);
4565         }
4566 out_unlock:
4567         nr = trans->blocks_used;
4568         btrfs_end_transaction_throttle(trans, root);
4569         btrfs_btree_balance_dirty(root, nr);
4570         if (drop_inode) {
4571                 inode_dec_link_count(inode);
4572                 iput(inode);
4573         }
4574         return err;
4575 }
4576
4577 static int btrfs_create(struct inode *dir, struct dentry *dentry,
4578                         int mode, struct nameidata *nd)
4579 {
4580         struct btrfs_trans_handle *trans;
4581         struct btrfs_root *root = BTRFS_I(dir)->root;
4582         struct inode *inode = NULL;
4583         int drop_inode = 0;
4584         int err;
4585         unsigned long nr = 0;
4586         u64 objectid;
4587         u64 index = 0;
4588
4589         /*
4590          * 2 for inode item and ref
4591          * 2 for dir items
4592          * 1 for xattr if selinux is on
4593          */
4594         trans = btrfs_start_transaction(root, 5);
4595         if (IS_ERR(trans))
4596                 return PTR_ERR(trans);
4597
4598         err = btrfs_find_free_ino(root, &objectid);
4599         if (err)
4600                 goto out_unlock;
4601
4602         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4603                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4604                                 mode, &index);
4605         if (IS_ERR(inode)) {
4606                 err = PTR_ERR(inode);
4607                 goto out_unlock;
4608         }
4609
4610         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4611         if (err) {
4612                 drop_inode = 1;
4613                 goto out_unlock;
4614         }
4615
4616         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4617         if (err)
4618                 drop_inode = 1;
4619         else {
4620                 inode->i_mapping->a_ops = &btrfs_aops;
4621                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
4622                 inode->i_fop = &btrfs_file_operations;
4623                 inode->i_op = &btrfs_file_inode_operations;
4624                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
4625         }
4626 out_unlock:
4627         nr = trans->blocks_used;
4628         btrfs_end_transaction_throttle(trans, root);
4629         if (drop_inode) {
4630                 inode_dec_link_count(inode);
4631                 iput(inode);
4632         }
4633         btrfs_btree_balance_dirty(root, nr);
4634         return err;
4635 }
4636
4637 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
4638                       struct dentry *dentry)
4639 {
4640         struct btrfs_trans_handle *trans;
4641         struct btrfs_root *root = BTRFS_I(dir)->root;
4642         struct inode *inode = old_dentry->d_inode;
4643         u64 index;
4644         unsigned long nr = 0;
4645         int err;
4646         int drop_inode = 0;
4647
4648         /* do not allow sys_link's with other subvols of the same device */
4649         if (root->objectid != BTRFS_I(inode)->root->objectid)
4650                 return -EXDEV;
4651
4652         if (inode->i_nlink == ~0U)
4653                 return -EMLINK;
4654
4655         err = btrfs_set_inode_index(dir, &index);
4656         if (err)
4657                 goto fail;
4658
4659         /*
4660          * 2 items for inode and inode ref
4661          * 2 items for dir items
4662          * 1 item for parent inode
4663          */
4664         trans = btrfs_start_transaction(root, 5);
4665         if (IS_ERR(trans)) {
4666                 err = PTR_ERR(trans);
4667                 goto fail;
4668         }
4669
4670         btrfs_inc_nlink(inode);
4671         inode->i_ctime = CURRENT_TIME;
4672         ihold(inode);
4673
4674         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
4675
4676         if (err) {
4677                 drop_inode = 1;
4678         } else {
4679                 struct dentry *parent = dentry->d_parent;
4680                 err = btrfs_update_inode(trans, root, inode);
4681                 BUG_ON(err);
4682                 btrfs_log_new_name(trans, inode, NULL, parent);
4683         }
4684
4685         nr = trans->blocks_used;
4686         btrfs_end_transaction_throttle(trans, root);
4687 fail:
4688         if (drop_inode) {
4689                 inode_dec_link_count(inode);
4690                 iput(inode);
4691         }
4692         btrfs_btree_balance_dirty(root, nr);
4693         return err;
4694 }
4695
4696 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
4697 {
4698         struct inode *inode = NULL;
4699         struct btrfs_trans_handle *trans;
4700         struct btrfs_root *root = BTRFS_I(dir)->root;
4701         int err = 0;
4702         int drop_on_err = 0;
4703         u64 objectid = 0;
4704         u64 index = 0;
4705         unsigned long nr = 1;
4706
4707         /*
4708          * 2 items for inode and ref
4709          * 2 items for dir items
4710          * 1 for xattr if selinux is on
4711          */
4712         trans = btrfs_start_transaction(root, 5);
4713         if (IS_ERR(trans))
4714                 return PTR_ERR(trans);
4715
4716         err = btrfs_find_free_ino(root, &objectid);
4717         if (err)
4718                 goto out_fail;
4719
4720         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4721                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4722                                 S_IFDIR | mode, &index);
4723         if (IS_ERR(inode)) {
4724                 err = PTR_ERR(inode);
4725                 goto out_fail;
4726         }
4727
4728         drop_on_err = 1;
4729
4730         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4731         if (err)
4732                 goto out_fail;
4733
4734         inode->i_op = &btrfs_dir_inode_operations;
4735         inode->i_fop = &btrfs_dir_file_operations;
4736
4737         btrfs_i_size_write(inode, 0);
4738         err = btrfs_update_inode(trans, root, inode);
4739         if (err)
4740                 goto out_fail;
4741
4742         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
4743                              dentry->d_name.len, 0, index);
4744         if (err)
4745                 goto out_fail;
4746
4747         d_instantiate(dentry, inode);
4748         drop_on_err = 0;
4749
4750 out_fail:
4751         nr = trans->blocks_used;
4752         btrfs_end_transaction_throttle(trans, root);
4753         if (drop_on_err)
4754                 iput(inode);
4755         btrfs_btree_balance_dirty(root, nr);
4756         return err;
4757 }
4758
4759 /* helper for btfs_get_extent.  Given an existing extent in the tree,
4760  * and an extent that you want to insert, deal with overlap and insert
4761  * the new extent into the tree.
4762  */
4763 static int merge_extent_mapping(struct extent_map_tree *em_tree,
4764                                 struct extent_map *existing,
4765                                 struct extent_map *em,
4766                                 u64 map_start, u64 map_len)
4767 {
4768         u64 start_diff;
4769
4770         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
4771         start_diff = map_start - em->start;
4772         em->start = map_start;
4773         em->len = map_len;
4774         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
4775             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
4776                 em->block_start += start_diff;
4777                 em->block_len -= start_diff;
4778         }
4779         return add_extent_mapping(em_tree, em);
4780 }
4781
4782 static noinline int uncompress_inline(struct btrfs_path *path,
4783                                       struct inode *inode, struct page *page,
4784                                       size_t pg_offset, u64 extent_offset,
4785                                       struct btrfs_file_extent_item *item)
4786 {
4787         int ret;
4788         struct extent_buffer *leaf = path->nodes[0];
4789         char *tmp;
4790         size_t max_size;
4791         unsigned long inline_size;
4792         unsigned long ptr;
4793         int compress_type;
4794
4795         WARN_ON(pg_offset != 0);
4796         compress_type = btrfs_file_extent_compression(leaf, item);
4797         max_size = btrfs_file_extent_ram_bytes(leaf, item);
4798         inline_size = btrfs_file_extent_inline_item_len(leaf,
4799                                         btrfs_item_nr(leaf, path->slots[0]));
4800         tmp = kmalloc(inline_size, GFP_NOFS);
4801         if (!tmp)
4802                 return -ENOMEM;
4803         ptr = btrfs_file_extent_inline_start(item);
4804
4805         read_extent_buffer(leaf, tmp, ptr, inline_size);
4806
4807         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
4808         ret = btrfs_decompress(compress_type, tmp, page,
4809                                extent_offset, inline_size, max_size);
4810         if (ret) {
4811                 char *kaddr = kmap_atomic(page, KM_USER0);
4812                 unsigned long copy_size = min_t(u64,
4813                                   PAGE_CACHE_SIZE - pg_offset,
4814                                   max_size - extent_offset);
4815                 memset(kaddr + pg_offset, 0, copy_size);
4816                 kunmap_atomic(kaddr, KM_USER0);
4817         }
4818         kfree(tmp);
4819         return 0;
4820 }
4821
4822 /*
4823  * a bit scary, this does extent mapping from logical file offset to the disk.
4824  * the ugly parts come from merging extents from the disk with the in-ram
4825  * representation.  This gets more complex because of the data=ordered code,
4826  * where the in-ram extents might be locked pending data=ordered completion.
4827  *
4828  * This also copies inline extents directly into the page.
4829  */
4830
4831 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
4832                                     size_t pg_offset, u64 start, u64 len,
4833                                     int create)
4834 {
4835         int ret;
4836         int err = 0;
4837         u64 bytenr;
4838         u64 extent_start = 0;
4839         u64 extent_end = 0;
4840         u64 objectid = btrfs_ino(inode);
4841         u32 found_type;
4842         struct btrfs_path *path = NULL;
4843         struct btrfs_root *root = BTRFS_I(inode)->root;
4844         struct btrfs_file_extent_item *item;
4845         struct extent_buffer *leaf;
4846         struct btrfs_key found_key;
4847         struct extent_map *em = NULL;
4848         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4849         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4850         struct btrfs_trans_handle *trans = NULL;
4851         int compress_type;
4852
4853 again:
4854         read_lock(&em_tree->lock);
4855         em = lookup_extent_mapping(em_tree, start, len);
4856         if (em)
4857                 em->bdev = root->fs_info->fs_devices->latest_bdev;
4858         read_unlock(&em_tree->lock);
4859
4860         if (em) {
4861                 if (em->start > start || em->start + em->len <= start)
4862                         free_extent_map(em);
4863                 else if (em->block_start == EXTENT_MAP_INLINE && page)
4864                         free_extent_map(em);
4865                 else
4866                         goto out;
4867         }
4868         em = alloc_extent_map();
4869         if (!em) {
4870                 err = -ENOMEM;
4871                 goto out;
4872         }
4873         em->bdev = root->fs_info->fs_devices->latest_bdev;
4874         em->start = EXTENT_MAP_HOLE;
4875         em->orig_start = EXTENT_MAP_HOLE;
4876         em->len = (u64)-1;
4877         em->block_len = (u64)-1;
4878
4879         if (!path) {
4880                 path = btrfs_alloc_path();
4881                 if (!path) {
4882                         err = -ENOMEM;
4883                         goto out;
4884                 }
4885                 /*
4886                  * Chances are we'll be called again, so go ahead and do
4887                  * readahead
4888                  */
4889                 path->reada = 1;
4890         }
4891
4892         ret = btrfs_lookup_file_extent(trans, root, path,
4893                                        objectid, start, trans != NULL);
4894         if (ret < 0) {
4895                 err = ret;
4896                 goto out;
4897         }
4898
4899         if (ret != 0) {
4900                 if (path->slots[0] == 0)
4901                         goto not_found;
4902                 path->slots[0]--;
4903         }
4904
4905         leaf = path->nodes[0];
4906         item = btrfs_item_ptr(leaf, path->slots[0],
4907                               struct btrfs_file_extent_item);
4908         /* are we inside the extent that was found? */
4909         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4910         found_type = btrfs_key_type(&found_key);
4911         if (found_key.objectid != objectid ||
4912             found_type != BTRFS_EXTENT_DATA_KEY) {
4913                 goto not_found;
4914         }
4915
4916         found_type = btrfs_file_extent_type(leaf, item);
4917         extent_start = found_key.offset;
4918         compress_type = btrfs_file_extent_compression(leaf, item);
4919         if (found_type == BTRFS_FILE_EXTENT_REG ||
4920             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
4921                 extent_end = extent_start +
4922                        btrfs_file_extent_num_bytes(leaf, item);
4923         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
4924                 size_t size;
4925                 size = btrfs_file_extent_inline_len(leaf, item);
4926                 extent_end = (extent_start + size + root->sectorsize - 1) &
4927                         ~((u64)root->sectorsize - 1);
4928         }
4929
4930         if (start >= extent_end) {
4931                 path->slots[0]++;
4932                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
4933                         ret = btrfs_next_leaf(root, path);
4934                         if (ret < 0) {
4935                                 err = ret;
4936                                 goto out;
4937                         }
4938                         if (ret > 0)
4939                                 goto not_found;
4940                         leaf = path->nodes[0];
4941                 }
4942                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4943                 if (found_key.objectid != objectid ||
4944                     found_key.type != BTRFS_EXTENT_DATA_KEY)
4945                         goto not_found;
4946                 if (start + len <= found_key.offset)
4947                         goto not_found;
4948                 em->start = start;
4949                 em->len = found_key.offset - start;
4950                 goto not_found_em;
4951         }
4952
4953         if (found_type == BTRFS_FILE_EXTENT_REG ||
4954             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
4955                 em->start = extent_start;
4956                 em->len = extent_end - extent_start;
4957                 em->orig_start = extent_start -
4958                                  btrfs_file_extent_offset(leaf, item);
4959                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
4960                 if (bytenr == 0) {
4961                         em->block_start = EXTENT_MAP_HOLE;
4962                         goto insert;
4963                 }
4964                 if (compress_type != BTRFS_COMPRESS_NONE) {
4965                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
4966                         em->compress_type = compress_type;
4967                         em->block_start = bytenr;
4968                         em->block_len = btrfs_file_extent_disk_num_bytes(leaf,
4969                                                                          item);
4970                 } else {
4971                         bytenr += btrfs_file_extent_offset(leaf, item);
4972                         em->block_start = bytenr;
4973                         em->block_len = em->len;
4974                         if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
4975                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
4976                 }
4977                 goto insert;
4978         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
4979                 unsigned long ptr;
4980                 char *map;
4981                 size_t size;
4982                 size_t extent_offset;
4983                 size_t copy_size;
4984
4985                 em->block_start = EXTENT_MAP_INLINE;
4986                 if (!page || create) {
4987                         em->start = extent_start;
4988                         em->len = extent_end - extent_start;
4989                         goto out;
4990                 }
4991
4992                 size = btrfs_file_extent_inline_len(leaf, item);
4993                 extent_offset = page_offset(page) + pg_offset - extent_start;
4994                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
4995                                 size - extent_offset);
4996                 em->start = extent_start + extent_offset;
4997                 em->len = (copy_size + root->sectorsize - 1) &
4998                         ~((u64)root->sectorsize - 1);
4999                 em->orig_start = EXTENT_MAP_INLINE;
5000                 if (compress_type) {
5001                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5002                         em->compress_type = compress_type;
5003                 }
5004                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
5005                 if (create == 0 && !PageUptodate(page)) {
5006                         if (btrfs_file_extent_compression(leaf, item) !=
5007                             BTRFS_COMPRESS_NONE) {
5008                                 ret = uncompress_inline(path, inode, page,
5009                                                         pg_offset,
5010                                                         extent_offset, item);
5011                                 BUG_ON(ret);
5012                         } else {
5013                                 map = kmap(page);
5014                                 read_extent_buffer(leaf, map + pg_offset, ptr,
5015                                                    copy_size);
5016                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
5017                                         memset(map + pg_offset + copy_size, 0,
5018                                                PAGE_CACHE_SIZE - pg_offset -
5019                                                copy_size);
5020                                 }
5021                                 kunmap(page);
5022                         }
5023                         flush_dcache_page(page);
5024                 } else if (create && PageUptodate(page)) {
5025                         WARN_ON(1);
5026                         if (!trans) {
5027                                 kunmap(page);
5028                                 free_extent_map(em);
5029                                 em = NULL;
5030
5031                                 btrfs_release_path(path);
5032                                 trans = btrfs_join_transaction(root);
5033
5034                                 if (IS_ERR(trans))
5035                                         return ERR_CAST(trans);
5036                                 goto again;
5037                         }
5038                         map = kmap(page);
5039                         write_extent_buffer(leaf, map + pg_offset, ptr,
5040                                             copy_size);
5041                         kunmap(page);
5042                         btrfs_mark_buffer_dirty(leaf);
5043                 }
5044                 set_extent_uptodate(io_tree, em->start,
5045                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
5046                 goto insert;
5047         } else {
5048                 printk(KERN_ERR "btrfs unknown found_type %d\n", found_type);
5049                 WARN_ON(1);
5050         }
5051 not_found:
5052         em->start = start;
5053         em->len = len;
5054 not_found_em:
5055         em->block_start = EXTENT_MAP_HOLE;
5056         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
5057 insert:
5058         btrfs_release_path(path);
5059         if (em->start > start || extent_map_end(em) <= start) {
5060                 printk(KERN_ERR "Btrfs: bad extent! em: [%llu %llu] passed "
5061                        "[%llu %llu]\n", (unsigned long long)em->start,
5062                        (unsigned long long)em->len,
5063                        (unsigned long long)start,
5064                        (unsigned long long)len);
5065                 err = -EIO;
5066                 goto out;
5067         }
5068
5069         err = 0;
5070         write_lock(&em_tree->lock);
5071         ret = add_extent_mapping(em_tree, em);
5072         /* it is possible that someone inserted the extent into the tree
5073          * while we had the lock dropped.  It is also possible that
5074          * an overlapping map exists in the tree
5075          */
5076         if (ret == -EEXIST) {
5077                 struct extent_map *existing;
5078
5079                 ret = 0;
5080
5081                 existing = lookup_extent_mapping(em_tree, start, len);
5082                 if (existing && (existing->start > start ||
5083                     existing->start + existing->len <= start)) {
5084                         free_extent_map(existing);
5085                         existing = NULL;
5086                 }
5087                 if (!existing) {
5088                         existing = lookup_extent_mapping(em_tree, em->start,
5089                                                          em->len);
5090                         if (existing) {
5091                                 err = merge_extent_mapping(em_tree, existing,
5092                                                            em, start,
5093                                                            root->sectorsize);
5094                                 free_extent_map(existing);
5095                                 if (err) {
5096                                         free_extent_map(em);
5097                                         em = NULL;
5098                                 }
5099                         } else {
5100                                 err = -EIO;
5101                                 free_extent_map(em);
5102                                 em = NULL;
5103                         }
5104                 } else {
5105                         free_extent_map(em);
5106                         em = existing;
5107                         err = 0;
5108                 }
5109         }
5110         write_unlock(&em_tree->lock);
5111 out:
5112
5113         trace_btrfs_get_extent(root, em);
5114
5115         if (path)
5116                 btrfs_free_path(path);
5117         if (trans) {
5118                 ret = btrfs_end_transaction(trans, root);
5119                 if (!err)
5120                         err = ret;
5121         }
5122         if (err) {
5123                 free_extent_map(em);
5124                 return ERR_PTR(err);
5125         }
5126         return em;
5127 }
5128
5129 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
5130                                            size_t pg_offset, u64 start, u64 len,
5131                                            int create)
5132 {
5133         struct extent_map *em;
5134         struct extent_map *hole_em = NULL;
5135         u64 range_start = start;
5136         u64 end;
5137         u64 found;
5138         u64 found_end;
5139         int err = 0;
5140
5141         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
5142         if (IS_ERR(em))
5143                 return em;
5144         if (em) {
5145                 /*
5146                  * if our em maps to a hole, there might
5147                  * actually be delalloc bytes behind it
5148                  */
5149                 if (em->block_start != EXTENT_MAP_HOLE)
5150                         return em;
5151                 else
5152                         hole_em = em;
5153         }
5154
5155         /* check to see if we've wrapped (len == -1 or similar) */
5156         end = start + len;
5157         if (end < start)
5158                 end = (u64)-1;
5159         else
5160                 end -= 1;
5161
5162         em = NULL;
5163
5164         /* ok, we didn't find anything, lets look for delalloc */
5165         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
5166                                  end, len, EXTENT_DELALLOC, 1);
5167         found_end = range_start + found;
5168         if (found_end < range_start)
5169                 found_end = (u64)-1;
5170
5171         /*
5172          * we didn't find anything useful, return
5173          * the original results from get_extent()
5174          */
5175         if (range_start > end || found_end <= start) {
5176                 em = hole_em;
5177                 hole_em = NULL;
5178                 goto out;
5179         }
5180
5181         /* adjust the range_start to make sure it doesn't
5182          * go backwards from the start they passed in
5183          */
5184         range_start = max(start,range_start);
5185         found = found_end - range_start;
5186
5187         if (found > 0) {
5188                 u64 hole_start = start;
5189                 u64 hole_len = len;
5190
5191                 em = alloc_extent_map();
5192                 if (!em) {
5193                         err = -ENOMEM;
5194                         goto out;
5195                 }
5196                 /*
5197                  * when btrfs_get_extent can't find anything it
5198                  * returns one huge hole
5199                  *
5200                  * make sure what it found really fits our range, and
5201                  * adjust to make sure it is based on the start from
5202                  * the caller
5203                  */
5204                 if (hole_em) {
5205                         u64 calc_end = extent_map_end(hole_em);
5206
5207                         if (calc_end <= start || (hole_em->start > end)) {
5208                                 free_extent_map(hole_em);
5209                                 hole_em = NULL;
5210                         } else {
5211                                 hole_start = max(hole_em->start, start);
5212                                 hole_len = calc_end - hole_start;
5213                         }
5214                 }
5215                 em->bdev = NULL;
5216                 if (hole_em && range_start > hole_start) {
5217                         /* our hole starts before our delalloc, so we
5218                          * have to return just the parts of the hole
5219                          * that go until  the delalloc starts
5220                          */
5221                         em->len = min(hole_len,
5222                                       range_start - hole_start);
5223                         em->start = hole_start;
5224                         em->orig_start = hole_start;
5225                         /*
5226                          * don't adjust block start at all,
5227                          * it is fixed at EXTENT_MAP_HOLE
5228                          */
5229                         em->block_start = hole_em->block_start;
5230                         em->block_len = hole_len;
5231                 } else {
5232                         em->start = range_start;
5233                         em->len = found;
5234                         em->orig_start = range_start;
5235                         em->block_start = EXTENT_MAP_DELALLOC;
5236                         em->block_len = found;
5237                 }
5238         } else if (hole_em) {
5239                 return hole_em;
5240         }
5241 out:
5242
5243         free_extent_map(hole_em);
5244         if (err) {
5245                 free_extent_map(em);
5246                 return ERR_PTR(err);
5247         }
5248         return em;
5249 }
5250
5251 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
5252                                                   struct extent_map *em,
5253                                                   u64 start, u64 len)
5254 {
5255         struct btrfs_root *root = BTRFS_I(inode)->root;
5256         struct btrfs_trans_handle *trans;
5257         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
5258         struct btrfs_key ins;
5259         u64 alloc_hint;
5260         int ret;
5261         bool insert = false;
5262
5263         /*
5264          * Ok if the extent map we looked up is a hole and is for the exact
5265          * range we want, there is no reason to allocate a new one, however if
5266          * it is not right then we need to free this one and drop the cache for
5267          * our range.
5268          */
5269         if (em->block_start != EXTENT_MAP_HOLE || em->start != start ||
5270             em->len != len) {
5271                 free_extent_map(em);
5272                 em = NULL;
5273                 insert = true;
5274                 btrfs_drop_extent_cache(inode, start, start + len - 1, 0);
5275         }
5276
5277         trans = btrfs_join_transaction(root);
5278         if (IS_ERR(trans))
5279                 return ERR_CAST(trans);
5280
5281         if (start <= BTRFS_I(inode)->disk_i_size && len < 64 * 1024)
5282                 btrfs_add_inode_defrag(trans, inode);
5283
5284         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
5285
5286         alloc_hint = get_extent_allocation_hint(inode, start, len);
5287         ret = btrfs_reserve_extent(trans, root, len, root->sectorsize, 0,
5288                                    alloc_hint, (u64)-1, &ins, 1);
5289         if (ret) {
5290                 em = ERR_PTR(ret);
5291                 goto out;
5292         }
5293
5294         if (!em) {
5295                 em = alloc_extent_map();
5296                 if (!em) {
5297                         em = ERR_PTR(-ENOMEM);
5298                         goto out;
5299                 }
5300         }
5301
5302         em->start = start;
5303         em->orig_start = em->start;
5304         em->len = ins.offset;
5305
5306         em->block_start = ins.objectid;
5307         em->block_len = ins.offset;
5308         em->bdev = root->fs_info->fs_devices->latest_bdev;
5309
5310         /*
5311          * We need to do this because if we're using the original em we searched
5312          * for, we could have EXTENT_FLAG_VACANCY set, and we don't want that.
5313          */
5314         em->flags = 0;
5315         set_bit(EXTENT_FLAG_PINNED, &em->flags);
5316
5317         while (insert) {
5318                 write_lock(&em_tree->lock);
5319                 ret = add_extent_mapping(em_tree, em);
5320                 write_unlock(&em_tree->lock);
5321                 if (ret != -EEXIST)
5322                         break;
5323                 btrfs_drop_extent_cache(inode, start, start + em->len - 1, 0);
5324         }
5325
5326         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
5327                                            ins.offset, ins.offset, 0);
5328         if (ret) {
5329                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
5330                 em = ERR_PTR(ret);
5331         }
5332 out:
5333         btrfs_end_transaction(trans, root);
5334         return em;
5335 }
5336
5337 /*
5338  * returns 1 when the nocow is safe, < 1 on error, 0 if the
5339  * block must be cow'd
5340  */
5341 static noinline int can_nocow_odirect(struct btrfs_trans_handle *trans,
5342                                       struct inode *inode, u64 offset, u64 len)
5343 {
5344         struct btrfs_path *path;
5345         int ret;
5346         struct extent_buffer *leaf;
5347         struct btrfs_root *root = BTRFS_I(inode)->root;
5348         struct btrfs_file_extent_item *fi;
5349         struct btrfs_key key;
5350         u64 disk_bytenr;
5351         u64 backref_offset;
5352         u64 extent_end;
5353         u64 num_bytes;
5354         int slot;
5355         int found_type;
5356
5357         path = btrfs_alloc_path();
5358         if (!path)
5359                 return -ENOMEM;
5360
5361         ret = btrfs_lookup_file_extent(trans, root, path, btrfs_ino(inode),
5362                                        offset, 0);
5363         if (ret < 0)
5364                 goto out;
5365
5366         slot = path->slots[0];
5367         if (ret == 1) {
5368                 if (slot == 0) {
5369                         /* can't find the item, must cow */
5370                         ret = 0;
5371                         goto out;
5372                 }
5373                 slot--;
5374         }
5375         ret = 0;
5376         leaf = path->nodes[0];
5377         btrfs_item_key_to_cpu(leaf, &key, slot);
5378         if (key.objectid != btrfs_ino(inode) ||
5379             key.type != BTRFS_EXTENT_DATA_KEY) {
5380                 /* not our file or wrong item type, must cow */
5381                 goto out;
5382         }
5383
5384         if (key.offset > offset) {
5385                 /* Wrong offset, must cow */
5386                 goto out;
5387         }
5388
5389         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
5390         found_type = btrfs_file_extent_type(leaf, fi);
5391         if (found_type != BTRFS_FILE_EXTENT_REG &&
5392             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
5393                 /* not a regular extent, must cow */
5394                 goto out;
5395         }
5396         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
5397         backref_offset = btrfs_file_extent_offset(leaf, fi);
5398
5399         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
5400         if (extent_end < offset + len) {
5401                 /* extent doesn't include our full range, must cow */
5402                 goto out;
5403         }
5404
5405         if (btrfs_extent_readonly(root, disk_bytenr))
5406                 goto out;
5407
5408         /*
5409          * look for other files referencing this extent, if we
5410          * find any we must cow
5411          */
5412         if (btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
5413                                   key.offset - backref_offset, disk_bytenr))
5414                 goto out;
5415
5416         /*
5417          * adjust disk_bytenr and num_bytes to cover just the bytes
5418          * in this extent we are about to write.  If there
5419          * are any csums in that range we have to cow in order
5420          * to keep the csums correct
5421          */
5422         disk_bytenr += backref_offset;
5423         disk_bytenr += offset - key.offset;
5424         num_bytes = min(offset + len, extent_end) - offset;
5425         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
5426                                 goto out;
5427         /*
5428          * all of the above have passed, it is safe to overwrite this extent
5429          * without cow
5430          */
5431         ret = 1;
5432 out:
5433         btrfs_free_path(path);
5434         return ret;
5435 }
5436
5437 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
5438                                    struct buffer_head *bh_result, int create)
5439 {
5440         struct extent_map *em;
5441         struct btrfs_root *root = BTRFS_I(inode)->root;
5442         u64 start = iblock << inode->i_blkbits;
5443         u64 len = bh_result->b_size;
5444         struct btrfs_trans_handle *trans;
5445
5446         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
5447         if (IS_ERR(em))
5448                 return PTR_ERR(em);
5449
5450         /*
5451          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
5452          * io.  INLINE is special, and we could probably kludge it in here, but
5453          * it's still buffered so for safety lets just fall back to the generic
5454          * buffered path.
5455          *
5456          * For COMPRESSED we _have_ to read the entire extent in so we can
5457          * decompress it, so there will be buffering required no matter what we
5458          * do, so go ahead and fallback to buffered.
5459          *
5460          * We return -ENOTBLK because thats what makes DIO go ahead and go back
5461          * to buffered IO.  Don't blame me, this is the price we pay for using
5462          * the generic code.
5463          */
5464         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
5465             em->block_start == EXTENT_MAP_INLINE) {
5466                 free_extent_map(em);
5467                 return -ENOTBLK;
5468         }
5469
5470         /* Just a good old fashioned hole, return */
5471         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
5472                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
5473                 free_extent_map(em);
5474                 /* DIO will do one hole at a time, so just unlock a sector */
5475                 unlock_extent(&BTRFS_I(inode)->io_tree, start,
5476                               start + root->sectorsize - 1, GFP_NOFS);
5477                 return 0;
5478         }
5479
5480         /*
5481          * We don't allocate a new extent in the following cases
5482          *
5483          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
5484          * existing extent.
5485          * 2) The extent is marked as PREALLOC.  We're good to go here and can
5486          * just use the extent.
5487          *
5488          */
5489         if (!create) {
5490                 len = em->len - (start - em->start);
5491                 goto map;
5492         }
5493
5494         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
5495             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
5496              em->block_start != EXTENT_MAP_HOLE)) {
5497                 int type;
5498                 int ret;
5499                 u64 block_start;
5500
5501                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
5502                         type = BTRFS_ORDERED_PREALLOC;
5503                 else
5504                         type = BTRFS_ORDERED_NOCOW;
5505                 len = min(len, em->len - (start - em->start));
5506                 block_start = em->block_start + (start - em->start);
5507
5508                 /*
5509                  * we're not going to log anything, but we do need
5510                  * to make sure the current transaction stays open
5511                  * while we look for nocow cross refs
5512                  */
5513                 trans = btrfs_join_transaction(root);
5514                 if (IS_ERR(trans))
5515                         goto must_cow;
5516
5517                 if (can_nocow_odirect(trans, inode, start, len) == 1) {
5518                         ret = btrfs_add_ordered_extent_dio(inode, start,
5519                                            block_start, len, len, type);
5520                         btrfs_end_transaction(trans, root);
5521                         if (ret) {
5522                                 free_extent_map(em);
5523                                 return ret;
5524                         }
5525                         goto unlock;
5526                 }
5527                 btrfs_end_transaction(trans, root);
5528         }
5529 must_cow:
5530         /*
5531          * this will cow the extent, reset the len in case we changed
5532          * it above
5533          */
5534         len = bh_result->b_size;
5535         em = btrfs_new_extent_direct(inode, em, start, len);
5536         if (IS_ERR(em))
5537                 return PTR_ERR(em);
5538         len = min(len, em->len - (start - em->start));
5539 unlock:
5540         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, start + len - 1,
5541                           EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DIRTY, 1,
5542                           0, NULL, GFP_NOFS);
5543 map:
5544         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
5545                 inode->i_blkbits;
5546         bh_result->b_size = len;
5547         bh_result->b_bdev = em->bdev;
5548         set_buffer_mapped(bh_result);
5549         if (create && !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
5550                 set_buffer_new(bh_result);
5551
5552         free_extent_map(em);
5553
5554         return 0;
5555 }
5556
5557 struct btrfs_dio_private {
5558         struct inode *inode;
5559         u64 logical_offset;
5560         u64 disk_bytenr;
5561         u64 bytes;
5562         u32 *csums;
5563         void *private;
5564
5565         /* number of bios pending for this dio */
5566         atomic_t pending_bios;
5567
5568         /* IO errors */
5569         int errors;
5570
5571         struct bio *orig_bio;
5572 };
5573
5574 static void btrfs_endio_direct_read(struct bio *bio, int err)
5575 {
5576         struct btrfs_dio_private *dip = bio->bi_private;
5577         struct bio_vec *bvec_end = bio->bi_io_vec + bio->bi_vcnt - 1;
5578         struct bio_vec *bvec = bio->bi_io_vec;
5579         struct inode *inode = dip->inode;
5580         struct btrfs_root *root = BTRFS_I(inode)->root;
5581         u64 start;
5582         u32 *private = dip->csums;
5583
5584         start = dip->logical_offset;
5585         do {
5586                 if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)) {
5587                         struct page *page = bvec->bv_page;
5588                         char *kaddr;
5589                         u32 csum = ~(u32)0;
5590                         unsigned long flags;
5591
5592                         local_irq_save(flags);
5593                         kaddr = kmap_atomic(page, KM_IRQ0);
5594                         csum = btrfs_csum_data(root, kaddr + bvec->bv_offset,
5595                                                csum, bvec->bv_len);
5596                         btrfs_csum_final(csum, (char *)&csum);
5597                         kunmap_atomic(kaddr, KM_IRQ0);
5598                         local_irq_restore(flags);
5599
5600                         flush_dcache_page(bvec->bv_page);
5601                         if (csum != *private) {
5602                                 printk(KERN_ERR "btrfs csum failed ino %llu off"
5603                                       " %llu csum %u private %u\n",
5604                                       (unsigned long long)btrfs_ino(inode),
5605                                       (unsigned long long)start,
5606                                       csum, *private);
5607                                 err = -EIO;
5608                         }
5609                 }
5610
5611                 start += bvec->bv_len;
5612                 private++;
5613                 bvec++;
5614         } while (bvec <= bvec_end);
5615
5616         unlock_extent(&BTRFS_I(inode)->io_tree, dip->logical_offset,
5617                       dip->logical_offset + dip->bytes - 1, GFP_NOFS);
5618         bio->bi_private = dip->private;
5619
5620         kfree(dip->csums);
5621         kfree(dip);
5622
5623         /* If we had a csum failure make sure to clear the uptodate flag */
5624         if (err)
5625                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
5626         dio_end_io(bio, err);
5627 }
5628
5629 static void btrfs_endio_direct_write(struct bio *bio, int err)
5630 {
5631         struct btrfs_dio_private *dip = bio->bi_private;
5632         struct inode *inode = dip->inode;