Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable
[~shefty/rdma-dev.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 "compat.h"
41 #include "ctree.h"
42 #include "disk-io.h"
43 #include "transaction.h"
44 #include "btrfs_inode.h"
45 #include "ioctl.h"
46 #include "print-tree.h"
47 #include "volumes.h"
48 #include "ordered-data.h"
49 #include "xattr.h"
50 #include "tree-log.h"
51 #include "compression.h"
52 #include "locking.h"
53
54 struct btrfs_iget_args {
55         u64 ino;
56         struct btrfs_root *root;
57 };
58
59 static const struct inode_operations btrfs_dir_inode_operations;
60 static const struct inode_operations btrfs_symlink_inode_operations;
61 static const struct inode_operations btrfs_dir_ro_inode_operations;
62 static const struct inode_operations btrfs_special_inode_operations;
63 static const struct inode_operations btrfs_file_inode_operations;
64 static const struct address_space_operations btrfs_aops;
65 static const struct address_space_operations btrfs_symlink_aops;
66 static const struct file_operations btrfs_dir_file_operations;
67 static struct extent_io_ops btrfs_extent_io_ops;
68
69 static struct kmem_cache *btrfs_inode_cachep;
70 struct kmem_cache *btrfs_trans_handle_cachep;
71 struct kmem_cache *btrfs_transaction_cachep;
72 struct kmem_cache *btrfs_path_cachep;
73
74 #define S_SHIFT 12
75 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
76         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
77         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
78         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
79         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
80         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
81         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
82         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
83 };
84
85 static void btrfs_truncate(struct inode *inode);
86 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end);
87 static noinline int cow_file_range(struct inode *inode,
88                                    struct page *locked_page,
89                                    u64 start, u64 end, int *page_started,
90                                    unsigned long *nr_written, int unlock);
91
92 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
93                                      struct inode *inode,  struct inode *dir)
94 {
95         int err;
96
97         err = btrfs_init_acl(trans, inode, dir);
98         if (!err)
99                 err = btrfs_xattr_security_init(trans, inode, dir);
100         return err;
101 }
102
103 /*
104  * this does all the hard work for inserting an inline extent into
105  * the btree.  The caller should have done a btrfs_drop_extents so that
106  * no overlapping inline items exist in the btree
107  */
108 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
109                                 struct btrfs_root *root, struct inode *inode,
110                                 u64 start, size_t size, size_t compressed_size,
111                                 struct page **compressed_pages)
112 {
113         struct btrfs_key key;
114         struct btrfs_path *path;
115         struct extent_buffer *leaf;
116         struct page *page = NULL;
117         char *kaddr;
118         unsigned long ptr;
119         struct btrfs_file_extent_item *ei;
120         int err = 0;
121         int ret;
122         size_t cur_size = size;
123         size_t datasize;
124         unsigned long offset;
125         int use_compress = 0;
126
127         if (compressed_size && compressed_pages) {
128                 use_compress = 1;
129                 cur_size = compressed_size;
130         }
131
132         path = btrfs_alloc_path();
133         if (!path)
134                 return -ENOMEM;
135
136         path->leave_spinning = 1;
137         btrfs_set_trans_block_group(trans, inode);
138
139         key.objectid = inode->i_ino;
140         key.offset = start;
141         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
142         datasize = btrfs_file_extent_calc_inline_size(cur_size);
143
144         inode_add_bytes(inode, size);
145         ret = btrfs_insert_empty_item(trans, root, path, &key,
146                                       datasize);
147         BUG_ON(ret);
148         if (ret) {
149                 err = ret;
150                 goto fail;
151         }
152         leaf = path->nodes[0];
153         ei = btrfs_item_ptr(leaf, path->slots[0],
154                             struct btrfs_file_extent_item);
155         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
156         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
157         btrfs_set_file_extent_encryption(leaf, ei, 0);
158         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
159         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
160         ptr = btrfs_file_extent_inline_start(ei);
161
162         if (use_compress) {
163                 struct page *cpage;
164                 int i = 0;
165                 while (compressed_size > 0) {
166                         cpage = compressed_pages[i];
167                         cur_size = min_t(unsigned long, compressed_size,
168                                        PAGE_CACHE_SIZE);
169
170                         kaddr = kmap_atomic(cpage, KM_USER0);
171                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
172                         kunmap_atomic(kaddr, KM_USER0);
173
174                         i++;
175                         ptr += cur_size;
176                         compressed_size -= cur_size;
177                 }
178                 btrfs_set_file_extent_compression(leaf, ei,
179                                                   BTRFS_COMPRESS_ZLIB);
180         } else {
181                 page = find_get_page(inode->i_mapping,
182                                      start >> PAGE_CACHE_SHIFT);
183                 btrfs_set_file_extent_compression(leaf, ei, 0);
184                 kaddr = kmap_atomic(page, KM_USER0);
185                 offset = start & (PAGE_CACHE_SIZE - 1);
186                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
187                 kunmap_atomic(kaddr, KM_USER0);
188                 page_cache_release(page);
189         }
190         btrfs_mark_buffer_dirty(leaf);
191         btrfs_free_path(path);
192
193         /*
194          * we're an inline extent, so nobody can
195          * extend the file past i_size without locking
196          * a page we already have locked.
197          *
198          * We must do any isize and inode updates
199          * before we unlock the pages.  Otherwise we
200          * could end up racing with unlink.
201          */
202         BTRFS_I(inode)->disk_i_size = inode->i_size;
203         btrfs_update_inode(trans, root, inode);
204
205         return 0;
206 fail:
207         btrfs_free_path(path);
208         return err;
209 }
210
211
212 /*
213  * conditionally insert an inline extent into the file.  This
214  * does the checks required to make sure the data is small enough
215  * to fit as an inline extent.
216  */
217 static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans,
218                                  struct btrfs_root *root,
219                                  struct inode *inode, u64 start, u64 end,
220                                  size_t compressed_size,
221                                  struct page **compressed_pages)
222 {
223         u64 isize = i_size_read(inode);
224         u64 actual_end = min(end + 1, isize);
225         u64 inline_len = actual_end - start;
226         u64 aligned_end = (end + root->sectorsize - 1) &
227                         ~((u64)root->sectorsize - 1);
228         u64 hint_byte;
229         u64 data_len = inline_len;
230         int ret;
231
232         if (compressed_size)
233                 data_len = compressed_size;
234
235         if (start > 0 ||
236             actual_end >= PAGE_CACHE_SIZE ||
237             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
238             (!compressed_size &&
239             (actual_end & (root->sectorsize - 1)) == 0) ||
240             end + 1 < isize ||
241             data_len > root->fs_info->max_inline) {
242                 return 1;
243         }
244
245         ret = btrfs_drop_extents(trans, inode, start, aligned_end,
246                                  &hint_byte, 1);
247         BUG_ON(ret);
248
249         if (isize > actual_end)
250                 inline_len = min_t(u64, isize, actual_end);
251         ret = insert_inline_extent(trans, root, inode, start,
252                                    inline_len, compressed_size,
253                                    compressed_pages);
254         BUG_ON(ret);
255         btrfs_delalloc_release_metadata(inode, end + 1 - start);
256         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
257         return 0;
258 }
259
260 struct async_extent {
261         u64 start;
262         u64 ram_size;
263         u64 compressed_size;
264         struct page **pages;
265         unsigned long nr_pages;
266         struct list_head list;
267 };
268
269 struct async_cow {
270         struct inode *inode;
271         struct btrfs_root *root;
272         struct page *locked_page;
273         u64 start;
274         u64 end;
275         struct list_head extents;
276         struct btrfs_work work;
277 };
278
279 static noinline int add_async_extent(struct async_cow *cow,
280                                      u64 start, u64 ram_size,
281                                      u64 compressed_size,
282                                      struct page **pages,
283                                      unsigned long nr_pages)
284 {
285         struct async_extent *async_extent;
286
287         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
288         async_extent->start = start;
289         async_extent->ram_size = ram_size;
290         async_extent->compressed_size = compressed_size;
291         async_extent->pages = pages;
292         async_extent->nr_pages = nr_pages;
293         list_add_tail(&async_extent->list, &cow->extents);
294         return 0;
295 }
296
297 /*
298  * we create compressed extents in two phases.  The first
299  * phase compresses a range of pages that have already been
300  * locked (both pages and state bits are locked).
301  *
302  * This is done inside an ordered work queue, and the compression
303  * is spread across many cpus.  The actual IO submission is step
304  * two, and the ordered work queue takes care of making sure that
305  * happens in the same order things were put onto the queue by
306  * writepages and friends.
307  *
308  * If this code finds it can't get good compression, it puts an
309  * entry onto the work queue to write the uncompressed bytes.  This
310  * makes sure that both compressed inodes and uncompressed inodes
311  * are written in the same order that pdflush sent them down.
312  */
313 static noinline int compress_file_range(struct inode *inode,
314                                         struct page *locked_page,
315                                         u64 start, u64 end,
316                                         struct async_cow *async_cow,
317                                         int *num_added)
318 {
319         struct btrfs_root *root = BTRFS_I(inode)->root;
320         struct btrfs_trans_handle *trans;
321         u64 num_bytes;
322         u64 blocksize = root->sectorsize;
323         u64 actual_end;
324         u64 isize = i_size_read(inode);
325         int ret = 0;
326         struct page **pages = NULL;
327         unsigned long nr_pages;
328         unsigned long nr_pages_ret = 0;
329         unsigned long total_compressed = 0;
330         unsigned long total_in = 0;
331         unsigned long max_compressed = 128 * 1024;
332         unsigned long max_uncompressed = 128 * 1024;
333         int i;
334         int will_compress;
335
336         actual_end = min_t(u64, isize, end + 1);
337 again:
338         will_compress = 0;
339         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
340         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
341
342         /*
343          * we don't want to send crud past the end of i_size through
344          * compression, that's just a waste of CPU time.  So, if the
345          * end of the file is before the start of our current
346          * requested range of bytes, we bail out to the uncompressed
347          * cleanup code that can deal with all of this.
348          *
349          * It isn't really the fastest way to fix things, but this is a
350          * very uncommon corner.
351          */
352         if (actual_end <= start)
353                 goto cleanup_and_bail_uncompressed;
354
355         total_compressed = actual_end - start;
356
357         /* we want to make sure that amount of ram required to uncompress
358          * an extent is reasonable, so we limit the total size in ram
359          * of a compressed extent to 128k.  This is a crucial number
360          * because it also controls how easily we can spread reads across
361          * cpus for decompression.
362          *
363          * We also want to make sure the amount of IO required to do
364          * a random read is reasonably small, so we limit the size of
365          * a compressed extent to 128k.
366          */
367         total_compressed = min(total_compressed, max_uncompressed);
368         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
369         num_bytes = max(blocksize,  num_bytes);
370         total_in = 0;
371         ret = 0;
372
373         /*
374          * we do compression for mount -o compress and when the
375          * inode has not been flagged as nocompress.  This flag can
376          * change at any time if we discover bad compression ratios.
377          */
378         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
379             (btrfs_test_opt(root, COMPRESS) ||
380              (BTRFS_I(inode)->force_compress))) {
381                 WARN_ON(pages);
382                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
383
384                 ret = btrfs_zlib_compress_pages(inode->i_mapping, start,
385                                                 total_compressed, pages,
386                                                 nr_pages, &nr_pages_ret,
387                                                 &total_in,
388                                                 &total_compressed,
389                                                 max_compressed);
390
391                 if (!ret) {
392                         unsigned long offset = total_compressed &
393                                 (PAGE_CACHE_SIZE - 1);
394                         struct page *page = pages[nr_pages_ret - 1];
395                         char *kaddr;
396
397                         /* zero the tail end of the last page, we might be
398                          * sending it down to disk
399                          */
400                         if (offset) {
401                                 kaddr = kmap_atomic(page, KM_USER0);
402                                 memset(kaddr + offset, 0,
403                                        PAGE_CACHE_SIZE - offset);
404                                 kunmap_atomic(kaddr, KM_USER0);
405                         }
406                         will_compress = 1;
407                 }
408         }
409         if (start == 0) {
410                 trans = btrfs_join_transaction(root, 1);
411                 BUG_ON(!trans);
412                 btrfs_set_trans_block_group(trans, inode);
413                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
414
415                 /* lets try to make an inline extent */
416                 if (ret || total_in < (actual_end - start)) {
417                         /* we didn't compress the entire range, try
418                          * to make an uncompressed inline extent.
419                          */
420                         ret = cow_file_range_inline(trans, root, inode,
421                                                     start, end, 0, NULL);
422                 } else {
423                         /* try making a compressed inline extent */
424                         ret = cow_file_range_inline(trans, root, inode,
425                                                     start, end,
426                                                     total_compressed, pages);
427                 }
428                 if (ret == 0) {
429                         /*
430                          * inline extent creation worked, we don't need
431                          * to create any more async work items.  Unlock
432                          * and free up our temp pages.
433                          */
434                         extent_clear_unlock_delalloc(inode,
435                              &BTRFS_I(inode)->io_tree,
436                              start, end, NULL,
437                              EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
438                              EXTENT_CLEAR_DELALLOC |
439                              EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK);
440
441                         btrfs_end_transaction(trans, root);
442                         goto free_pages_out;
443                 }
444                 btrfs_end_transaction(trans, root);
445         }
446
447         if (will_compress) {
448                 /*
449                  * we aren't doing an inline extent round the compressed size
450                  * up to a block size boundary so the allocator does sane
451                  * things
452                  */
453                 total_compressed = (total_compressed + blocksize - 1) &
454                         ~(blocksize - 1);
455
456                 /*
457                  * one last check to make sure the compression is really a
458                  * win, compare the page count read with the blocks on disk
459                  */
460                 total_in = (total_in + PAGE_CACHE_SIZE - 1) &
461                         ~(PAGE_CACHE_SIZE - 1);
462                 if (total_compressed >= total_in) {
463                         will_compress = 0;
464                 } else {
465                         num_bytes = total_in;
466                 }
467         }
468         if (!will_compress && pages) {
469                 /*
470                  * the compression code ran but failed to make things smaller,
471                  * free any pages it allocated and our page pointer array
472                  */
473                 for (i = 0; i < nr_pages_ret; i++) {
474                         WARN_ON(pages[i]->mapping);
475                         page_cache_release(pages[i]);
476                 }
477                 kfree(pages);
478                 pages = NULL;
479                 total_compressed = 0;
480                 nr_pages_ret = 0;
481
482                 /* flag the file so we don't compress in the future */
483                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
484                     !(BTRFS_I(inode)->force_compress)) {
485                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
486                 }
487         }
488         if (will_compress) {
489                 *num_added += 1;
490
491                 /* the async work queues will take care of doing actual
492                  * allocation on disk for these compressed pages,
493                  * and will submit them to the elevator.
494                  */
495                 add_async_extent(async_cow, start, num_bytes,
496                                  total_compressed, pages, nr_pages_ret);
497
498                 if (start + num_bytes < end && start + num_bytes < actual_end) {
499                         start += num_bytes;
500                         pages = NULL;
501                         cond_resched();
502                         goto again;
503                 }
504         } else {
505 cleanup_and_bail_uncompressed:
506                 /*
507                  * No compression, but we still need to write the pages in
508                  * the file we've been given so far.  redirty the locked
509                  * page if it corresponds to our extent and set things up
510                  * for the async work queue to run cow_file_range to do
511                  * the normal delalloc dance
512                  */
513                 if (page_offset(locked_page) >= start &&
514                     page_offset(locked_page) <= end) {
515                         __set_page_dirty_nobuffers(locked_page);
516                         /* unlocked later on in the async handlers */
517                 }
518                 add_async_extent(async_cow, start, end - start + 1, 0, NULL, 0);
519                 *num_added += 1;
520         }
521
522 out:
523         return 0;
524
525 free_pages_out:
526         for (i = 0; i < nr_pages_ret; i++) {
527                 WARN_ON(pages[i]->mapping);
528                 page_cache_release(pages[i]);
529         }
530         kfree(pages);
531
532         goto out;
533 }
534
535 /*
536  * phase two of compressed writeback.  This is the ordered portion
537  * of the code, which only gets called in the order the work was
538  * queued.  We walk all the async extents created by compress_file_range
539  * and send them down to the disk.
540  */
541 static noinline int submit_compressed_extents(struct inode *inode,
542                                               struct async_cow *async_cow)
543 {
544         struct async_extent *async_extent;
545         u64 alloc_hint = 0;
546         struct btrfs_trans_handle *trans;
547         struct btrfs_key ins;
548         struct extent_map *em;
549         struct btrfs_root *root = BTRFS_I(inode)->root;
550         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
551         struct extent_io_tree *io_tree;
552         int ret = 0;
553
554         if (list_empty(&async_cow->extents))
555                 return 0;
556
557
558         while (!list_empty(&async_cow->extents)) {
559                 async_extent = list_entry(async_cow->extents.next,
560                                           struct async_extent, list);
561                 list_del(&async_extent->list);
562
563                 io_tree = &BTRFS_I(inode)->io_tree;
564
565 retry:
566                 /* did the compression code fall back to uncompressed IO? */
567                 if (!async_extent->pages) {
568                         int page_started = 0;
569                         unsigned long nr_written = 0;
570
571                         lock_extent(io_tree, async_extent->start,
572                                          async_extent->start +
573                                          async_extent->ram_size - 1, GFP_NOFS);
574
575                         /* allocate blocks */
576                         ret = cow_file_range(inode, async_cow->locked_page,
577                                              async_extent->start,
578                                              async_extent->start +
579                                              async_extent->ram_size - 1,
580                                              &page_started, &nr_written, 0);
581
582                         /*
583                          * if page_started, cow_file_range inserted an
584                          * inline extent and took care of all the unlocking
585                          * and IO for us.  Otherwise, we need to submit
586                          * all those pages down to the drive.
587                          */
588                         if (!page_started && !ret)
589                                 extent_write_locked_range(io_tree,
590                                                   inode, async_extent->start,
591                                                   async_extent->start +
592                                                   async_extent->ram_size - 1,
593                                                   btrfs_get_extent,
594                                                   WB_SYNC_ALL);
595                         kfree(async_extent);
596                         cond_resched();
597                         continue;
598                 }
599
600                 lock_extent(io_tree, async_extent->start,
601                             async_extent->start + async_extent->ram_size - 1,
602                             GFP_NOFS);
603
604                 trans = btrfs_join_transaction(root, 1);
605                 ret = btrfs_reserve_extent(trans, root,
606                                            async_extent->compressed_size,
607                                            async_extent->compressed_size,
608                                            0, alloc_hint,
609                                            (u64)-1, &ins, 1);
610                 btrfs_end_transaction(trans, root);
611
612                 if (ret) {
613                         int i;
614                         for (i = 0; i < async_extent->nr_pages; i++) {
615                                 WARN_ON(async_extent->pages[i]->mapping);
616                                 page_cache_release(async_extent->pages[i]);
617                         }
618                         kfree(async_extent->pages);
619                         async_extent->nr_pages = 0;
620                         async_extent->pages = NULL;
621                         unlock_extent(io_tree, async_extent->start,
622                                       async_extent->start +
623                                       async_extent->ram_size - 1, GFP_NOFS);
624                         goto retry;
625                 }
626
627                 /*
628                  * here we're doing allocation and writeback of the
629                  * compressed pages
630                  */
631                 btrfs_drop_extent_cache(inode, async_extent->start,
632                                         async_extent->start +
633                                         async_extent->ram_size - 1, 0);
634
635                 em = alloc_extent_map(GFP_NOFS);
636                 em->start = async_extent->start;
637                 em->len = async_extent->ram_size;
638                 em->orig_start = em->start;
639
640                 em->block_start = ins.objectid;
641                 em->block_len = ins.offset;
642                 em->bdev = root->fs_info->fs_devices->latest_bdev;
643                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
644                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
645
646                 while (1) {
647                         write_lock(&em_tree->lock);
648                         ret = add_extent_mapping(em_tree, em);
649                         write_unlock(&em_tree->lock);
650                         if (ret != -EEXIST) {
651                                 free_extent_map(em);
652                                 break;
653                         }
654                         btrfs_drop_extent_cache(inode, async_extent->start,
655                                                 async_extent->start +
656                                                 async_extent->ram_size - 1, 0);
657                 }
658
659                 ret = btrfs_add_ordered_extent(inode, async_extent->start,
660                                                ins.objectid,
661                                                async_extent->ram_size,
662                                                ins.offset,
663                                                BTRFS_ORDERED_COMPRESSED);
664                 BUG_ON(ret);
665
666                 /*
667                  * clear dirty, set writeback and unlock the pages.
668                  */
669                 extent_clear_unlock_delalloc(inode,
670                                 &BTRFS_I(inode)->io_tree,
671                                 async_extent->start,
672                                 async_extent->start +
673                                 async_extent->ram_size - 1,
674                                 NULL, EXTENT_CLEAR_UNLOCK_PAGE |
675                                 EXTENT_CLEAR_UNLOCK |
676                                 EXTENT_CLEAR_DELALLOC |
677                                 EXTENT_CLEAR_DIRTY | EXTENT_SET_WRITEBACK);
678
679                 ret = btrfs_submit_compressed_write(inode,
680                                     async_extent->start,
681                                     async_extent->ram_size,
682                                     ins.objectid,
683                                     ins.offset, async_extent->pages,
684                                     async_extent->nr_pages);
685
686                 BUG_ON(ret);
687                 alloc_hint = ins.objectid + ins.offset;
688                 kfree(async_extent);
689                 cond_resched();
690         }
691
692         return 0;
693 }
694
695 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
696                                       u64 num_bytes)
697 {
698         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
699         struct extent_map *em;
700         u64 alloc_hint = 0;
701
702         read_lock(&em_tree->lock);
703         em = search_extent_mapping(em_tree, start, num_bytes);
704         if (em) {
705                 /*
706                  * if block start isn't an actual block number then find the
707                  * first block in this inode and use that as a hint.  If that
708                  * block is also bogus then just don't worry about it.
709                  */
710                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
711                         free_extent_map(em);
712                         em = search_extent_mapping(em_tree, 0, 0);
713                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
714                                 alloc_hint = em->block_start;
715                         if (em)
716                                 free_extent_map(em);
717                 } else {
718                         alloc_hint = em->block_start;
719                         free_extent_map(em);
720                 }
721         }
722         read_unlock(&em_tree->lock);
723
724         return alloc_hint;
725 }
726
727 /*
728  * when extent_io.c finds a delayed allocation range in the file,
729  * the call backs end up in this code.  The basic idea is to
730  * allocate extents on disk for the range, and create ordered data structs
731  * in ram to track those extents.
732  *
733  * locked_page is the page that writepage had locked already.  We use
734  * it to make sure we don't do extra locks or unlocks.
735  *
736  * *page_started is set to one if we unlock locked_page and do everything
737  * required to start IO on it.  It may be clean and already done with
738  * IO when we return.
739  */
740 static noinline int cow_file_range(struct inode *inode,
741                                    struct page *locked_page,
742                                    u64 start, u64 end, int *page_started,
743                                    unsigned long *nr_written,
744                                    int unlock)
745 {
746         struct btrfs_root *root = BTRFS_I(inode)->root;
747         struct btrfs_trans_handle *trans;
748         u64 alloc_hint = 0;
749         u64 num_bytes;
750         unsigned long ram_size;
751         u64 disk_num_bytes;
752         u64 cur_alloc_size;
753         u64 blocksize = root->sectorsize;
754         struct btrfs_key ins;
755         struct extent_map *em;
756         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
757         int ret = 0;
758
759         BUG_ON(root == root->fs_info->tree_root);
760         trans = btrfs_join_transaction(root, 1);
761         BUG_ON(!trans);
762         btrfs_set_trans_block_group(trans, inode);
763         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
764
765         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
766         num_bytes = max(blocksize,  num_bytes);
767         disk_num_bytes = num_bytes;
768         ret = 0;
769
770         if (start == 0) {
771                 /* lets try to make an inline extent */
772                 ret = cow_file_range_inline(trans, root, inode,
773                                             start, end, 0, NULL);
774                 if (ret == 0) {
775                         extent_clear_unlock_delalloc(inode,
776                                      &BTRFS_I(inode)->io_tree,
777                                      start, end, NULL,
778                                      EXTENT_CLEAR_UNLOCK_PAGE |
779                                      EXTENT_CLEAR_UNLOCK |
780                                      EXTENT_CLEAR_DELALLOC |
781                                      EXTENT_CLEAR_DIRTY |
782                                      EXTENT_SET_WRITEBACK |
783                                      EXTENT_END_WRITEBACK);
784
785                         *nr_written = *nr_written +
786                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
787                         *page_started = 1;
788                         ret = 0;
789                         goto out;
790                 }
791         }
792
793         BUG_ON(disk_num_bytes >
794                btrfs_super_total_bytes(&root->fs_info->super_copy));
795
796         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
797         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
798
799         while (disk_num_bytes > 0) {
800                 unsigned long op;
801
802                 cur_alloc_size = disk_num_bytes;
803                 ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
804                                            root->sectorsize, 0, alloc_hint,
805                                            (u64)-1, &ins, 1);
806                 BUG_ON(ret);
807
808                 em = alloc_extent_map(GFP_NOFS);
809                 em->start = start;
810                 em->orig_start = em->start;
811                 ram_size = ins.offset;
812                 em->len = ins.offset;
813
814                 em->block_start = ins.objectid;
815                 em->block_len = ins.offset;
816                 em->bdev = root->fs_info->fs_devices->latest_bdev;
817                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
818
819                 while (1) {
820                         write_lock(&em_tree->lock);
821                         ret = add_extent_mapping(em_tree, em);
822                         write_unlock(&em_tree->lock);
823                         if (ret != -EEXIST) {
824                                 free_extent_map(em);
825                                 break;
826                         }
827                         btrfs_drop_extent_cache(inode, start,
828                                                 start + ram_size - 1, 0);
829                 }
830
831                 cur_alloc_size = ins.offset;
832                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
833                                                ram_size, cur_alloc_size, 0);
834                 BUG_ON(ret);
835
836                 if (root->root_key.objectid ==
837                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
838                         ret = btrfs_reloc_clone_csums(inode, start,
839                                                       cur_alloc_size);
840                         BUG_ON(ret);
841                 }
842
843                 if (disk_num_bytes < cur_alloc_size)
844                         break;
845
846                 /* we're not doing compressed IO, don't unlock the first
847                  * page (which the caller expects to stay locked), don't
848                  * clear any dirty bits and don't set any writeback bits
849                  *
850                  * Do set the Private2 bit so we know this page was properly
851                  * setup for writepage
852                  */
853                 op = unlock ? EXTENT_CLEAR_UNLOCK_PAGE : 0;
854                 op |= EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
855                         EXTENT_SET_PRIVATE2;
856
857                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
858                                              start, start + ram_size - 1,
859                                              locked_page, op);
860                 disk_num_bytes -= cur_alloc_size;
861                 num_bytes -= cur_alloc_size;
862                 alloc_hint = ins.objectid + ins.offset;
863                 start += cur_alloc_size;
864         }
865 out:
866         ret = 0;
867         btrfs_end_transaction(trans, root);
868
869         return ret;
870 }
871
872 /*
873  * work queue call back to started compression on a file and pages
874  */
875 static noinline void async_cow_start(struct btrfs_work *work)
876 {
877         struct async_cow *async_cow;
878         int num_added = 0;
879         async_cow = container_of(work, struct async_cow, work);
880
881         compress_file_range(async_cow->inode, async_cow->locked_page,
882                             async_cow->start, async_cow->end, async_cow,
883                             &num_added);
884         if (num_added == 0)
885                 async_cow->inode = NULL;
886 }
887
888 /*
889  * work queue call back to submit previously compressed pages
890  */
891 static noinline void async_cow_submit(struct btrfs_work *work)
892 {
893         struct async_cow *async_cow;
894         struct btrfs_root *root;
895         unsigned long nr_pages;
896
897         async_cow = container_of(work, struct async_cow, work);
898
899         root = async_cow->root;
900         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
901                 PAGE_CACHE_SHIFT;
902
903         atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
904
905         if (atomic_read(&root->fs_info->async_delalloc_pages) <
906             5 * 1042 * 1024 &&
907             waitqueue_active(&root->fs_info->async_submit_wait))
908                 wake_up(&root->fs_info->async_submit_wait);
909
910         if (async_cow->inode)
911                 submit_compressed_extents(async_cow->inode, async_cow);
912 }
913
914 static noinline void async_cow_free(struct btrfs_work *work)
915 {
916         struct async_cow *async_cow;
917         async_cow = container_of(work, struct async_cow, work);
918         kfree(async_cow);
919 }
920
921 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
922                                 u64 start, u64 end, int *page_started,
923                                 unsigned long *nr_written)
924 {
925         struct async_cow *async_cow;
926         struct btrfs_root *root = BTRFS_I(inode)->root;
927         unsigned long nr_pages;
928         u64 cur_end;
929         int limit = 10 * 1024 * 1042;
930
931         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
932                          1, 0, NULL, GFP_NOFS);
933         while (start < end) {
934                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
935                 async_cow->inode = inode;
936                 async_cow->root = root;
937                 async_cow->locked_page = locked_page;
938                 async_cow->start = start;
939
940                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
941                         cur_end = end;
942                 else
943                         cur_end = min(end, start + 512 * 1024 - 1);
944
945                 async_cow->end = cur_end;
946                 INIT_LIST_HEAD(&async_cow->extents);
947
948                 async_cow->work.func = async_cow_start;
949                 async_cow->work.ordered_func = async_cow_submit;
950                 async_cow->work.ordered_free = async_cow_free;
951                 async_cow->work.flags = 0;
952
953                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
954                         PAGE_CACHE_SHIFT;
955                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
956
957                 btrfs_queue_worker(&root->fs_info->delalloc_workers,
958                                    &async_cow->work);
959
960                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
961                         wait_event(root->fs_info->async_submit_wait,
962                            (atomic_read(&root->fs_info->async_delalloc_pages) <
963                             limit));
964                 }
965
966                 while (atomic_read(&root->fs_info->async_submit_draining) &&
967                       atomic_read(&root->fs_info->async_delalloc_pages)) {
968                         wait_event(root->fs_info->async_submit_wait,
969                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
970                            0));
971                 }
972
973                 *nr_written += nr_pages;
974                 start = cur_end + 1;
975         }
976         *page_started = 1;
977         return 0;
978 }
979
980 static noinline int csum_exist_in_range(struct btrfs_root *root,
981                                         u64 bytenr, u64 num_bytes)
982 {
983         int ret;
984         struct btrfs_ordered_sum *sums;
985         LIST_HEAD(list);
986
987         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
988                                        bytenr + num_bytes - 1, &list);
989         if (ret == 0 && list_empty(&list))
990                 return 0;
991
992         while (!list_empty(&list)) {
993                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
994                 list_del(&sums->list);
995                 kfree(sums);
996         }
997         return 1;
998 }
999
1000 /*
1001  * when nowcow writeback call back.  This checks for snapshots or COW copies
1002  * of the extents that exist in the file, and COWs the file as required.
1003  *
1004  * If no cow copies or snapshots exist, we write directly to the existing
1005  * blocks on disk
1006  */
1007 static noinline int run_delalloc_nocow(struct inode *inode,
1008                                        struct page *locked_page,
1009                               u64 start, u64 end, int *page_started, int force,
1010                               unsigned long *nr_written)
1011 {
1012         struct btrfs_root *root = BTRFS_I(inode)->root;
1013         struct btrfs_trans_handle *trans;
1014         struct extent_buffer *leaf;
1015         struct btrfs_path *path;
1016         struct btrfs_file_extent_item *fi;
1017         struct btrfs_key found_key;
1018         u64 cow_start;
1019         u64 cur_offset;
1020         u64 extent_end;
1021         u64 extent_offset;
1022         u64 disk_bytenr;
1023         u64 num_bytes;
1024         int extent_type;
1025         int ret;
1026         int type;
1027         int nocow;
1028         int check_prev = 1;
1029         bool nolock = false;
1030
1031         path = btrfs_alloc_path();
1032         BUG_ON(!path);
1033         if (root == root->fs_info->tree_root) {
1034                 nolock = true;
1035                 trans = btrfs_join_transaction_nolock(root, 1);
1036         } else {
1037                 trans = btrfs_join_transaction(root, 1);
1038         }
1039         BUG_ON(!trans);
1040
1041         cow_start = (u64)-1;
1042         cur_offset = start;
1043         while (1) {
1044                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
1045                                                cur_offset, 0);
1046                 BUG_ON(ret < 0);
1047                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1048                         leaf = path->nodes[0];
1049                         btrfs_item_key_to_cpu(leaf, &found_key,
1050                                               path->slots[0] - 1);
1051                         if (found_key.objectid == inode->i_ino &&
1052                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1053                                 path->slots[0]--;
1054                 }
1055                 check_prev = 0;
1056 next_slot:
1057                 leaf = path->nodes[0];
1058                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1059                         ret = btrfs_next_leaf(root, path);
1060                         if (ret < 0)
1061                                 BUG_ON(1);
1062                         if (ret > 0)
1063                                 break;
1064                         leaf = path->nodes[0];
1065                 }
1066
1067                 nocow = 0;
1068                 disk_bytenr = 0;
1069                 num_bytes = 0;
1070                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1071
1072                 if (found_key.objectid > inode->i_ino ||
1073                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1074                     found_key.offset > end)
1075                         break;
1076
1077                 if (found_key.offset > cur_offset) {
1078                         extent_end = found_key.offset;
1079                         extent_type = 0;
1080                         goto out_check;
1081                 }
1082
1083                 fi = btrfs_item_ptr(leaf, path->slots[0],
1084                                     struct btrfs_file_extent_item);
1085                 extent_type = btrfs_file_extent_type(leaf, fi);
1086
1087                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1088                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1089                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1090                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1091                         extent_end = found_key.offset +
1092                                 btrfs_file_extent_num_bytes(leaf, fi);
1093                         if (extent_end <= start) {
1094                                 path->slots[0]++;
1095                                 goto next_slot;
1096                         }
1097                         if (disk_bytenr == 0)
1098                                 goto out_check;
1099                         if (btrfs_file_extent_compression(leaf, fi) ||
1100                             btrfs_file_extent_encryption(leaf, fi) ||
1101                             btrfs_file_extent_other_encoding(leaf, fi))
1102                                 goto out_check;
1103                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1104                                 goto out_check;
1105                         if (btrfs_extent_readonly(root, disk_bytenr))
1106                                 goto out_check;
1107                         if (btrfs_cross_ref_exist(trans, root, inode->i_ino,
1108                                                   found_key.offset -
1109                                                   extent_offset, disk_bytenr))
1110                                 goto out_check;
1111                         disk_bytenr += extent_offset;
1112                         disk_bytenr += cur_offset - found_key.offset;
1113                         num_bytes = min(end + 1, extent_end) - cur_offset;
1114                         /*
1115                          * force cow if csum exists in the range.
1116                          * this ensure that csum for a given extent are
1117                          * either valid or do not exist.
1118                          */
1119                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1120                                 goto out_check;
1121                         nocow = 1;
1122                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1123                         extent_end = found_key.offset +
1124                                 btrfs_file_extent_inline_len(leaf, fi);
1125                         extent_end = ALIGN(extent_end, root->sectorsize);
1126                 } else {
1127                         BUG_ON(1);
1128                 }
1129 out_check:
1130                 if (extent_end <= start) {
1131                         path->slots[0]++;
1132                         goto next_slot;
1133                 }
1134                 if (!nocow) {
1135                         if (cow_start == (u64)-1)
1136                                 cow_start = cur_offset;
1137                         cur_offset = extent_end;
1138                         if (cur_offset > end)
1139                                 break;
1140                         path->slots[0]++;
1141                         goto next_slot;
1142                 }
1143
1144                 btrfs_release_path(root, path);
1145                 if (cow_start != (u64)-1) {
1146                         ret = cow_file_range(inode, locked_page, cow_start,
1147                                         found_key.offset - 1, page_started,
1148                                         nr_written, 1);
1149                         BUG_ON(ret);
1150                         cow_start = (u64)-1;
1151                 }
1152
1153                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1154                         struct extent_map *em;
1155                         struct extent_map_tree *em_tree;
1156                         em_tree = &BTRFS_I(inode)->extent_tree;
1157                         em = alloc_extent_map(GFP_NOFS);
1158                         em->start = cur_offset;
1159                         em->orig_start = em->start;
1160                         em->len = num_bytes;
1161                         em->block_len = num_bytes;
1162                         em->block_start = disk_bytenr;
1163                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1164                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1165                         while (1) {
1166                                 write_lock(&em_tree->lock);
1167                                 ret = add_extent_mapping(em_tree, em);
1168                                 write_unlock(&em_tree->lock);
1169                                 if (ret != -EEXIST) {
1170                                         free_extent_map(em);
1171                                         break;
1172                                 }
1173                                 btrfs_drop_extent_cache(inode, em->start,
1174                                                 em->start + em->len - 1, 0);
1175                         }
1176                         type = BTRFS_ORDERED_PREALLOC;
1177                 } else {
1178                         type = BTRFS_ORDERED_NOCOW;
1179                 }
1180
1181                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1182                                                num_bytes, num_bytes, type);
1183                 BUG_ON(ret);
1184
1185                 if (root->root_key.objectid ==
1186                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1187                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1188                                                       num_bytes);
1189                         BUG_ON(ret);
1190                 }
1191
1192                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
1193                                 cur_offset, cur_offset + num_bytes - 1,
1194                                 locked_page, EXTENT_CLEAR_UNLOCK_PAGE |
1195                                 EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
1196                                 EXTENT_SET_PRIVATE2);
1197                 cur_offset = extent_end;
1198                 if (cur_offset > end)
1199                         break;
1200         }
1201         btrfs_release_path(root, path);
1202
1203         if (cur_offset <= end && cow_start == (u64)-1)
1204                 cow_start = cur_offset;
1205         if (cow_start != (u64)-1) {
1206                 ret = cow_file_range(inode, locked_page, cow_start, end,
1207                                      page_started, nr_written, 1);
1208                 BUG_ON(ret);
1209         }
1210
1211         if (nolock) {
1212                 ret = btrfs_end_transaction_nolock(trans, root);
1213                 BUG_ON(ret);
1214         } else {
1215                 ret = btrfs_end_transaction(trans, root);
1216                 BUG_ON(ret);
1217         }
1218         btrfs_free_path(path);
1219         return 0;
1220 }
1221
1222 /*
1223  * extent_io.c call back to do delayed allocation processing
1224  */
1225 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1226                               u64 start, u64 end, int *page_started,
1227                               unsigned long *nr_written)
1228 {
1229         int ret;
1230         struct btrfs_root *root = BTRFS_I(inode)->root;
1231
1232         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW)
1233                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1234                                          page_started, 1, nr_written);
1235         else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC)
1236                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1237                                          page_started, 0, nr_written);
1238         else if (!btrfs_test_opt(root, COMPRESS) &&
1239                  !(BTRFS_I(inode)->force_compress))
1240                 ret = cow_file_range(inode, locked_page, start, end,
1241                                       page_started, nr_written, 1);
1242         else
1243                 ret = cow_file_range_async(inode, locked_page, start, end,
1244                                            page_started, nr_written);
1245         return ret;
1246 }
1247
1248 static int btrfs_split_extent_hook(struct inode *inode,
1249                                    struct extent_state *orig, u64 split)
1250 {
1251         /* not delalloc, ignore it */
1252         if (!(orig->state & EXTENT_DELALLOC))
1253                 return 0;
1254
1255         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
1256         return 0;
1257 }
1258
1259 /*
1260  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1261  * extents so we can keep track of new extents that are just merged onto old
1262  * extents, such as when we are doing sequential writes, so we can properly
1263  * account for the metadata space we'll need.
1264  */
1265 static int btrfs_merge_extent_hook(struct inode *inode,
1266                                    struct extent_state *new,
1267                                    struct extent_state *other)
1268 {
1269         /* not delalloc, ignore it */
1270         if (!(other->state & EXTENT_DELALLOC))
1271                 return 0;
1272
1273         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
1274         return 0;
1275 }
1276
1277 /*
1278  * extent_io.c set_bit_hook, used to track delayed allocation
1279  * bytes in this file, and to maintain the list of inodes that
1280  * have pending delalloc work to be done.
1281  */
1282 static int btrfs_set_bit_hook(struct inode *inode,
1283                               struct extent_state *state, int *bits)
1284 {
1285
1286         /*
1287          * set_bit and clear bit hooks normally require _irqsave/restore
1288          * but in this case, we are only testeing for the DELALLOC
1289          * bit, which is only set or cleared with irqs on
1290          */
1291         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1292                 struct btrfs_root *root = BTRFS_I(inode)->root;
1293                 u64 len = state->end + 1 - state->start;
1294                 int do_list = (root->root_key.objectid !=
1295                                BTRFS_ROOT_TREE_OBJECTID);
1296
1297                 if (*bits & EXTENT_FIRST_DELALLOC)
1298                         *bits &= ~EXTENT_FIRST_DELALLOC;
1299                 else
1300                         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
1301
1302                 spin_lock(&root->fs_info->delalloc_lock);
1303                 BTRFS_I(inode)->delalloc_bytes += len;
1304                 root->fs_info->delalloc_bytes += len;
1305                 if (do_list && list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1306                         list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1307                                       &root->fs_info->delalloc_inodes);
1308                 }
1309                 spin_unlock(&root->fs_info->delalloc_lock);
1310         }
1311         return 0;
1312 }
1313
1314 /*
1315  * extent_io.c clear_bit_hook, see set_bit_hook for why
1316  */
1317 static int btrfs_clear_bit_hook(struct inode *inode,
1318                                 struct extent_state *state, int *bits)
1319 {
1320         /*
1321          * set_bit and clear bit hooks normally require _irqsave/restore
1322          * but in this case, we are only testeing for the DELALLOC
1323          * bit, which is only set or cleared with irqs on
1324          */
1325         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1326                 struct btrfs_root *root = BTRFS_I(inode)->root;
1327                 u64 len = state->end + 1 - state->start;
1328                 int do_list = (root->root_key.objectid !=
1329                                BTRFS_ROOT_TREE_OBJECTID);
1330
1331                 if (*bits & EXTENT_FIRST_DELALLOC)
1332                         *bits &= ~EXTENT_FIRST_DELALLOC;
1333                 else if (!(*bits & EXTENT_DO_ACCOUNTING))
1334                         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
1335
1336                 if (*bits & EXTENT_DO_ACCOUNTING)
1337                         btrfs_delalloc_release_metadata(inode, len);
1338
1339                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1340                     && do_list)
1341                         btrfs_free_reserved_data_space(inode, len);
1342
1343                 spin_lock(&root->fs_info->delalloc_lock);
1344                 root->fs_info->delalloc_bytes -= len;
1345                 BTRFS_I(inode)->delalloc_bytes -= len;
1346
1347                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1348                     !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1349                         list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1350                 }
1351                 spin_unlock(&root->fs_info->delalloc_lock);
1352         }
1353         return 0;
1354 }
1355
1356 /*
1357  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1358  * we don't create bios that span stripes or chunks
1359  */
1360 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1361                          size_t size, struct bio *bio,
1362                          unsigned long bio_flags)
1363 {
1364         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1365         struct btrfs_mapping_tree *map_tree;
1366         u64 logical = (u64)bio->bi_sector << 9;
1367         u64 length = 0;
1368         u64 map_length;
1369         int ret;
1370
1371         if (bio_flags & EXTENT_BIO_COMPRESSED)
1372                 return 0;
1373
1374         length = bio->bi_size;
1375         map_tree = &root->fs_info->mapping_tree;
1376         map_length = length;
1377         ret = btrfs_map_block(map_tree, READ, logical,
1378                               &map_length, NULL, 0);
1379
1380         if (map_length < length + size)
1381                 return 1;
1382         return ret;
1383 }
1384
1385 /*
1386  * in order to insert checksums into the metadata in large chunks,
1387  * we wait until bio submission time.   All the pages in the bio are
1388  * checksummed and sums are attached onto the ordered extent record.
1389  *
1390  * At IO completion time the cums attached on the ordered extent record
1391  * are inserted into the btree
1392  */
1393 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1394                                     struct bio *bio, int mirror_num,
1395                                     unsigned long bio_flags,
1396                                     u64 bio_offset)
1397 {
1398         struct btrfs_root *root = BTRFS_I(inode)->root;
1399         int ret = 0;
1400
1401         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1402         BUG_ON(ret);
1403         return 0;
1404 }
1405
1406 /*
1407  * in order to insert checksums into the metadata in large chunks,
1408  * we wait until bio submission time.   All the pages in the bio are
1409  * checksummed and sums are attached onto the ordered extent record.
1410  *
1411  * At IO completion time the cums attached on the ordered extent record
1412  * are inserted into the btree
1413  */
1414 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1415                           int mirror_num, unsigned long bio_flags,
1416                           u64 bio_offset)
1417 {
1418         struct btrfs_root *root = BTRFS_I(inode)->root;
1419         return btrfs_map_bio(root, rw, bio, mirror_num, 1);
1420 }
1421
1422 /*
1423  * extent_io.c submission hook. This does the right thing for csum calculation
1424  * on write, or reading the csums from the tree before a read
1425  */
1426 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1427                           int mirror_num, unsigned long bio_flags,
1428                           u64 bio_offset)
1429 {
1430         struct btrfs_root *root = BTRFS_I(inode)->root;
1431         int ret = 0;
1432         int skip_sum;
1433
1434         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1435
1436         if (root == root->fs_info->tree_root)
1437                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 2);
1438         else
1439                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
1440         BUG_ON(ret);
1441
1442         if (!(rw & REQ_WRITE)) {
1443                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1444                         return btrfs_submit_compressed_read(inode, bio,
1445                                                     mirror_num, bio_flags);
1446                 } else if (!skip_sum)
1447                         btrfs_lookup_bio_sums(root, inode, bio, NULL);
1448                 goto mapit;
1449         } else if (!skip_sum) {
1450                 /* csum items have already been cloned */
1451                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1452                         goto mapit;
1453                 /* we're doing a write, do the async checksumming */
1454                 return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1455                                    inode, rw, bio, mirror_num,
1456                                    bio_flags, bio_offset,
1457                                    __btrfs_submit_bio_start,
1458                                    __btrfs_submit_bio_done);
1459         }
1460
1461 mapit:
1462         return btrfs_map_bio(root, rw, bio, mirror_num, 0);
1463 }
1464
1465 /*
1466  * given a list of ordered sums record them in the inode.  This happens
1467  * at IO completion time based on sums calculated at bio submission time.
1468  */
1469 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1470                              struct inode *inode, u64 file_offset,
1471                              struct list_head *list)
1472 {
1473         struct btrfs_ordered_sum *sum;
1474
1475         btrfs_set_trans_block_group(trans, inode);
1476
1477         list_for_each_entry(sum, list, list) {
1478                 btrfs_csum_file_blocks(trans,
1479                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1480         }
1481         return 0;
1482 }
1483
1484 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1485                               struct extent_state **cached_state)
1486 {
1487         if ((end & (PAGE_CACHE_SIZE - 1)) == 0)
1488                 WARN_ON(1);
1489         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1490                                    cached_state, GFP_NOFS);
1491 }
1492
1493 /* see btrfs_writepage_start_hook for details on why this is required */
1494 struct btrfs_writepage_fixup {
1495         struct page *page;
1496         struct btrfs_work work;
1497 };
1498
1499 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1500 {
1501         struct btrfs_writepage_fixup *fixup;
1502         struct btrfs_ordered_extent *ordered;
1503         struct extent_state *cached_state = NULL;
1504         struct page *page;
1505         struct inode *inode;
1506         u64 page_start;
1507         u64 page_end;
1508
1509         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1510         page = fixup->page;
1511 again:
1512         lock_page(page);
1513         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1514                 ClearPageChecked(page);
1515                 goto out_page;
1516         }
1517
1518         inode = page->mapping->host;
1519         page_start = page_offset(page);
1520         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1521
1522         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1523                          &cached_state, GFP_NOFS);
1524
1525         /* already ordered? We're done */
1526         if (PagePrivate2(page))
1527                 goto out;
1528
1529         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1530         if (ordered) {
1531                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1532                                      page_end, &cached_state, GFP_NOFS);
1533                 unlock_page(page);
1534                 btrfs_start_ordered_extent(inode, ordered, 1);
1535                 goto again;
1536         }
1537
1538         BUG();
1539         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1540         ClearPageChecked(page);
1541 out:
1542         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1543                              &cached_state, GFP_NOFS);
1544 out_page:
1545         unlock_page(page);
1546         page_cache_release(page);
1547 }
1548
1549 /*
1550  * There are a few paths in the higher layers of the kernel that directly
1551  * set the page dirty bit without asking the filesystem if it is a
1552  * good idea.  This causes problems because we want to make sure COW
1553  * properly happens and the data=ordered rules are followed.
1554  *
1555  * In our case any range that doesn't have the ORDERED bit set
1556  * hasn't been properly setup for IO.  We kick off an async process
1557  * to fix it up.  The async helper will wait for ordered extents, set
1558  * the delalloc bit and make it safe to write the page.
1559  */
1560 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1561 {
1562         struct inode *inode = page->mapping->host;
1563         struct btrfs_writepage_fixup *fixup;
1564         struct btrfs_root *root = BTRFS_I(inode)->root;
1565
1566         /* this page is properly in the ordered list */
1567         if (TestClearPagePrivate2(page))
1568                 return 0;
1569
1570         if (PageChecked(page))
1571                 return -EAGAIN;
1572
1573         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1574         if (!fixup)
1575                 return -EAGAIN;
1576
1577         SetPageChecked(page);
1578         page_cache_get(page);
1579         fixup->work.func = btrfs_writepage_fixup_worker;
1580         fixup->page = page;
1581         btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
1582         return -EAGAIN;
1583 }
1584
1585 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1586                                        struct inode *inode, u64 file_pos,
1587                                        u64 disk_bytenr, u64 disk_num_bytes,
1588                                        u64 num_bytes, u64 ram_bytes,
1589                                        u8 compression, u8 encryption,
1590                                        u16 other_encoding, int extent_type)
1591 {
1592         struct btrfs_root *root = BTRFS_I(inode)->root;
1593         struct btrfs_file_extent_item *fi;
1594         struct btrfs_path *path;
1595         struct extent_buffer *leaf;
1596         struct btrfs_key ins;
1597         u64 hint;
1598         int ret;
1599
1600         path = btrfs_alloc_path();
1601         BUG_ON(!path);
1602
1603         path->leave_spinning = 1;
1604
1605         /*
1606          * we may be replacing one extent in the tree with another.
1607          * The new extent is pinned in the extent map, and we don't want
1608          * to drop it from the cache until it is completely in the btree.
1609          *
1610          * So, tell btrfs_drop_extents to leave this extent in the cache.
1611          * the caller is expected to unpin it and allow it to be merged
1612          * with the others.
1613          */
1614         ret = btrfs_drop_extents(trans, inode, file_pos, file_pos + num_bytes,
1615                                  &hint, 0);
1616         BUG_ON(ret);
1617
1618         ins.objectid = inode->i_ino;
1619         ins.offset = file_pos;
1620         ins.type = BTRFS_EXTENT_DATA_KEY;
1621         ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
1622         BUG_ON(ret);
1623         leaf = path->nodes[0];
1624         fi = btrfs_item_ptr(leaf, path->slots[0],
1625                             struct btrfs_file_extent_item);
1626         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1627         btrfs_set_file_extent_type(leaf, fi, extent_type);
1628         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1629         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1630         btrfs_set_file_extent_offset(leaf, fi, 0);
1631         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1632         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1633         btrfs_set_file_extent_compression(leaf, fi, compression);
1634         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1635         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1636
1637         btrfs_unlock_up_safe(path, 1);
1638         btrfs_set_lock_blocking(leaf);
1639
1640         btrfs_mark_buffer_dirty(leaf);
1641
1642         inode_add_bytes(inode, num_bytes);
1643
1644         ins.objectid = disk_bytenr;
1645         ins.offset = disk_num_bytes;
1646         ins.type = BTRFS_EXTENT_ITEM_KEY;
1647         ret = btrfs_alloc_reserved_file_extent(trans, root,
1648                                         root->root_key.objectid,
1649                                         inode->i_ino, file_pos, &ins);
1650         BUG_ON(ret);
1651         btrfs_free_path(path);
1652
1653         return 0;
1654 }
1655
1656 /*
1657  * helper function for btrfs_finish_ordered_io, this
1658  * just reads in some of the csum leaves to prime them into ram
1659  * before we start the transaction.  It limits the amount of btree
1660  * reads required while inside the transaction.
1661  */
1662 /* as ordered data IO finishes, this gets called so we can finish
1663  * an ordered extent if the range of bytes in the file it covers are
1664  * fully written.
1665  */
1666 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
1667 {
1668         struct btrfs_root *root = BTRFS_I(inode)->root;
1669         struct btrfs_trans_handle *trans = NULL;
1670         struct btrfs_ordered_extent *ordered_extent = NULL;
1671         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1672         struct extent_state *cached_state = NULL;
1673         int compressed = 0;
1674         int ret;
1675         bool nolock = false;
1676
1677         ret = btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
1678                                              end - start + 1);
1679         if (!ret)
1680                 return 0;
1681         BUG_ON(!ordered_extent);
1682
1683         nolock = (root == root->fs_info->tree_root);
1684
1685         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
1686                 BUG_ON(!list_empty(&ordered_extent->list));
1687                 ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1688                 if (!ret) {
1689                         if (nolock)
1690                                 trans = btrfs_join_transaction_nolock(root, 1);
1691                         else
1692                                 trans = btrfs_join_transaction(root, 1);
1693                         BUG_ON(!trans);
1694                         btrfs_set_trans_block_group(trans, inode);
1695                         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1696                         ret = btrfs_update_inode(trans, root, inode);
1697                         BUG_ON(ret);
1698                 }
1699                 goto out;
1700         }
1701
1702         lock_extent_bits(io_tree, ordered_extent->file_offset,
1703                          ordered_extent->file_offset + ordered_extent->len - 1,
1704                          0, &cached_state, GFP_NOFS);
1705
1706         if (nolock)
1707                 trans = btrfs_join_transaction_nolock(root, 1);
1708         else
1709                 trans = btrfs_join_transaction(root, 1);
1710         btrfs_set_trans_block_group(trans, inode);
1711         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1712
1713         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
1714                 compressed = 1;
1715         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1716                 BUG_ON(compressed);
1717                 ret = btrfs_mark_extent_written(trans, inode,
1718                                                 ordered_extent->file_offset,
1719                                                 ordered_extent->file_offset +
1720                                                 ordered_extent->len);
1721                 BUG_ON(ret);
1722         } else {
1723                 BUG_ON(root == root->fs_info->tree_root);
1724                 ret = insert_reserved_file_extent(trans, inode,
1725                                                 ordered_extent->file_offset,
1726                                                 ordered_extent->start,
1727                                                 ordered_extent->disk_len,
1728                                                 ordered_extent->len,
1729                                                 ordered_extent->len,
1730                                                 compressed, 0, 0,
1731                                                 BTRFS_FILE_EXTENT_REG);
1732                 unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
1733                                    ordered_extent->file_offset,
1734                                    ordered_extent->len);
1735                 BUG_ON(ret);
1736         }
1737         unlock_extent_cached(io_tree, ordered_extent->file_offset,
1738                              ordered_extent->file_offset +
1739                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
1740
1741         add_pending_csums(trans, inode, ordered_extent->file_offset,
1742                           &ordered_extent->list);
1743
1744         btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1745         ret = btrfs_update_inode(trans, root, inode);
1746         BUG_ON(ret);
1747 out:
1748         if (nolock) {
1749                 if (trans)
1750                         btrfs_end_transaction_nolock(trans, root);
1751         } else {
1752                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
1753                 if (trans)
1754                         btrfs_end_transaction(trans, root);
1755         }
1756
1757         /* once for us */
1758         btrfs_put_ordered_extent(ordered_extent);
1759         /* once for the tree */
1760         btrfs_put_ordered_extent(ordered_extent);
1761
1762         return 0;
1763 }
1764
1765 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
1766                                 struct extent_state *state, int uptodate)
1767 {
1768         ClearPagePrivate2(page);
1769         return btrfs_finish_ordered_io(page->mapping->host, start, end);
1770 }
1771
1772 /*
1773  * When IO fails, either with EIO or csum verification fails, we
1774  * try other mirrors that might have a good copy of the data.  This
1775  * io_failure_record is used to record state as we go through all the
1776  * mirrors.  If another mirror has good data, the page is set up to date
1777  * and things continue.  If a good mirror can't be found, the original
1778  * bio end_io callback is called to indicate things have failed.
1779  */
1780 struct io_failure_record {
1781         struct page *page;
1782         u64 start;
1783         u64 len;
1784         u64 logical;
1785         unsigned long bio_flags;
1786         int last_mirror;
1787 };
1788
1789 static int btrfs_io_failed_hook(struct bio *failed_bio,
1790                          struct page *page, u64 start, u64 end,
1791                          struct extent_state *state)
1792 {
1793         struct io_failure_record *failrec = NULL;
1794         u64 private;
1795         struct extent_map *em;
1796         struct inode *inode = page->mapping->host;
1797         struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
1798         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1799         struct bio *bio;
1800         int num_copies;
1801         int ret;
1802         int rw;
1803         u64 logical;
1804
1805         ret = get_state_private(failure_tree, start, &private);
1806         if (ret) {
1807                 failrec = kmalloc(sizeof(*failrec), GFP_NOFS);
1808                 if (!failrec)
1809                         return -ENOMEM;
1810                 failrec->start = start;
1811                 failrec->len = end - start + 1;
1812                 failrec->last_mirror = 0;
1813                 failrec->bio_flags = 0;
1814
1815                 read_lock(&em_tree->lock);
1816                 em = lookup_extent_mapping(em_tree, start, failrec->len);
1817                 if (em->start > start || em->start + em->len < start) {
1818                         free_extent_map(em);
1819                         em = NULL;
1820                 }
1821                 read_unlock(&em_tree->lock);
1822
1823                 if (!em || IS_ERR(em)) {
1824                         kfree(failrec);
1825                         return -EIO;
1826                 }
1827                 logical = start - em->start;
1828                 logical = em->block_start + logical;
1829                 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
1830                         logical = em->block_start;
1831                         failrec->bio_flags = EXTENT_BIO_COMPRESSED;
1832                 }
1833                 failrec->logical = logical;
1834                 free_extent_map(em);
1835                 set_extent_bits(failure_tree, start, end, EXTENT_LOCKED |
1836                                 EXTENT_DIRTY, GFP_NOFS);
1837                 set_state_private(failure_tree, start,
1838                                  (u64)(unsigned long)failrec);
1839         } else {
1840                 failrec = (struct io_failure_record *)(unsigned long)private;
1841         }
1842         num_copies = btrfs_num_copies(
1843                               &BTRFS_I(inode)->root->fs_info->mapping_tree,
1844                               failrec->logical, failrec->len);
1845         failrec->last_mirror++;
1846         if (!state) {
1847                 spin_lock(&BTRFS_I(inode)->io_tree.lock);
1848                 state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
1849                                                     failrec->start,
1850                                                     EXTENT_LOCKED);
1851                 if (state && state->start != failrec->start)
1852                         state = NULL;
1853                 spin_unlock(&BTRFS_I(inode)->io_tree.lock);
1854         }
1855         if (!state || failrec->last_mirror > num_copies) {
1856                 set_state_private(failure_tree, failrec->start, 0);
1857                 clear_extent_bits(failure_tree, failrec->start,
1858                                   failrec->start + failrec->len - 1,
1859                                   EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
1860                 kfree(failrec);
1861                 return -EIO;
1862         }
1863         bio = bio_alloc(GFP_NOFS, 1);
1864         bio->bi_private = state;
1865         bio->bi_end_io = failed_bio->bi_end_io;
1866         bio->bi_sector = failrec->logical >> 9;
1867         bio->bi_bdev = failed_bio->bi_bdev;
1868         bio->bi_size = 0;
1869
1870         bio_add_page(bio, page, failrec->len, start - page_offset(page));
1871         if (failed_bio->bi_rw & REQ_WRITE)
1872                 rw = WRITE;
1873         else
1874                 rw = READ;
1875
1876         BTRFS_I(inode)->io_tree.ops->submit_bio_hook(inode, rw, bio,
1877                                                       failrec->last_mirror,
1878                                                       failrec->bio_flags, 0);
1879         return 0;
1880 }
1881
1882 /*
1883  * each time an IO finishes, we do a fast check in the IO failure tree
1884  * to see if we need to process or clean up an io_failure_record
1885  */
1886 static int btrfs_clean_io_failures(struct inode *inode, u64 start)
1887 {
1888         u64 private;
1889         u64 private_failure;
1890         struct io_failure_record *failure;
1891         int ret;
1892
1893         private = 0;
1894         if (count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
1895                              (u64)-1, 1, EXTENT_DIRTY)) {
1896                 ret = get_state_private(&BTRFS_I(inode)->io_failure_tree,
1897                                         start, &private_failure);
1898                 if (ret == 0) {
1899                         failure = (struct io_failure_record *)(unsigned long)
1900                                    private_failure;
1901                         set_state_private(&BTRFS_I(inode)->io_failure_tree,
1902                                           failure->start, 0);
1903                         clear_extent_bits(&BTRFS_I(inode)->io_failure_tree,
1904                                           failure->start,
1905                                           failure->start + failure->len - 1,
1906                                           EXTENT_DIRTY | EXTENT_LOCKED,
1907                                           GFP_NOFS);
1908                         kfree(failure);
1909                 }
1910         }
1911         return 0;
1912 }
1913
1914 /*
1915  * when reads are done, we need to check csums to verify the data is correct
1916  * if there's a match, we allow the bio to finish.  If not, we go through
1917  * the io_failure_record routines to find good copies
1918  */
1919 static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
1920                                struct extent_state *state)
1921 {
1922         size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
1923         struct inode *inode = page->mapping->host;
1924         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1925         char *kaddr;
1926         u64 private = ~(u32)0;
1927         int ret;
1928         struct btrfs_root *root = BTRFS_I(inode)->root;
1929         u32 csum = ~(u32)0;
1930
1931         if (PageChecked(page)) {
1932                 ClearPageChecked(page);
1933                 goto good;
1934         }
1935
1936         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
1937                 return 0;
1938
1939         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
1940             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
1941                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
1942                                   GFP_NOFS);
1943                 return 0;
1944         }
1945
1946         if (state && state->start == start) {
1947                 private = state->private;
1948                 ret = 0;
1949         } else {
1950                 ret = get_state_private(io_tree, start, &private);
1951         }
1952         kaddr = kmap_atomic(page, KM_USER0);
1953         if (ret)
1954                 goto zeroit;
1955
1956         csum = btrfs_csum_data(root, kaddr + offset, csum,  end - start + 1);
1957         btrfs_csum_final(csum, (char *)&csum);
1958         if (csum != private)
1959                 goto zeroit;
1960
1961         kunmap_atomic(kaddr, KM_USER0);
1962 good:
1963         /* if the io failure tree for this inode is non-empty,
1964          * check to see if we've recovered from a failed IO
1965          */
1966         btrfs_clean_io_failures(inode, start);
1967         return 0;
1968
1969 zeroit:
1970         if (printk_ratelimit()) {
1971                 printk(KERN_INFO "btrfs csum failed ino %lu off %llu csum %u "
1972                        "private %llu\n", page->mapping->host->i_ino,
1973                        (unsigned long long)start, csum,
1974                        (unsigned long long)private);
1975         }
1976         memset(kaddr + offset, 1, end - start + 1);
1977         flush_dcache_page(page);
1978         kunmap_atomic(kaddr, KM_USER0);
1979         if (private == 0)
1980                 return 0;
1981         return -EIO;
1982 }
1983
1984 struct delayed_iput {
1985         struct list_head list;
1986         struct inode *inode;
1987 };
1988
1989 void btrfs_add_delayed_iput(struct inode *inode)
1990 {
1991         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
1992         struct delayed_iput *delayed;
1993
1994         if (atomic_add_unless(&inode->i_count, -1, 1))
1995                 return;
1996
1997         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
1998         delayed->inode = inode;
1999
2000         spin_lock(&fs_info->delayed_iput_lock);
2001         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
2002         spin_unlock(&fs_info->delayed_iput_lock);
2003 }
2004
2005 void btrfs_run_delayed_iputs(struct btrfs_root *root)
2006 {
2007         LIST_HEAD(list);
2008         struct btrfs_fs_info *fs_info = root->fs_info;
2009         struct delayed_iput *delayed;
2010         int empty;
2011
2012         spin_lock(&fs_info->delayed_iput_lock);
2013         empty = list_empty(&fs_info->delayed_iputs);
2014         spin_unlock(&fs_info->delayed_iput_lock);
2015         if (empty)
2016                 return;
2017
2018         down_read(&root->fs_info->cleanup_work_sem);
2019         spin_lock(&fs_info->delayed_iput_lock);
2020         list_splice_init(&fs_info->delayed_iputs, &list);
2021         spin_unlock(&fs_info->delayed_iput_lock);
2022
2023         while (!list_empty(&list)) {
2024                 delayed = list_entry(list.next, struct delayed_iput, list);
2025                 list_del(&delayed->list);
2026                 iput(delayed->inode);
2027                 kfree(delayed);
2028         }
2029         up_read(&root->fs_info->cleanup_work_sem);
2030 }
2031
2032 /*
2033  * calculate extra metadata reservation when snapshotting a subvolume
2034  * contains orphan files.
2035  */
2036 void btrfs_orphan_pre_snapshot(struct btrfs_trans_handle *trans,
2037                                 struct btrfs_pending_snapshot *pending,
2038                                 u64 *bytes_to_reserve)
2039 {
2040         struct btrfs_root *root;
2041         struct btrfs_block_rsv *block_rsv;
2042         u64 num_bytes;
2043         int index;
2044
2045         root = pending->root;
2046         if (!root->orphan_block_rsv || list_empty(&root->orphan_list))
2047                 return;
2048
2049         block_rsv = root->orphan_block_rsv;
2050
2051         /* orphan block reservation for the snapshot */
2052         num_bytes = block_rsv->size;
2053
2054         /*
2055          * after the snapshot is created, COWing tree blocks may use more
2056          * space than it frees. So we should make sure there is enough
2057          * reserved space.
2058          */
2059         index = trans->transid & 0x1;
2060         if (block_rsv->reserved + block_rsv->freed[index] < block_rsv->size) {
2061                 num_bytes += block_rsv->size -
2062                              (block_rsv->reserved + block_rsv->freed[index]);
2063         }
2064
2065         *bytes_to_reserve += num_bytes;
2066 }
2067
2068 void btrfs_orphan_post_snapshot(struct btrfs_trans_handle *trans,
2069                                 struct btrfs_pending_snapshot *pending)
2070 {
2071         struct btrfs_root *root = pending->root;
2072         struct btrfs_root *snap = pending->snap;
2073         struct btrfs_block_rsv *block_rsv;
2074         u64 num_bytes;
2075         int index;
2076         int ret;
2077
2078         if (!root->orphan_block_rsv || list_empty(&root->orphan_list))
2079                 return;
2080
2081         /* refill source subvolume's orphan block reservation */
2082         block_rsv = root->orphan_block_rsv;
2083         index = trans->transid & 0x1;
2084         if (block_rsv->reserved + block_rsv->freed[index] < block_rsv->size) {
2085                 num_bytes = block_rsv->size -
2086                             (block_rsv->reserved + block_rsv->freed[index]);
2087                 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
2088                                               root->orphan_block_rsv,
2089                                               num_bytes);
2090                 BUG_ON(ret);
2091         }
2092
2093         /* setup orphan block reservation for the snapshot */
2094         block_rsv = btrfs_alloc_block_rsv(snap);
2095         BUG_ON(!block_rsv);
2096
2097         btrfs_add_durable_block_rsv(root->fs_info, block_rsv);
2098         snap->orphan_block_rsv = block_rsv;
2099
2100         num_bytes = root->orphan_block_rsv->size;
2101         ret = btrfs_block_rsv_migrate(&pending->block_rsv,
2102                                       block_rsv, num_bytes);
2103         BUG_ON(ret);
2104
2105 #if 0
2106         /* insert orphan item for the snapshot */
2107         WARN_ON(!root->orphan_item_inserted);
2108         ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2109                                        snap->root_key.objectid);
2110         BUG_ON(ret);
2111         snap->orphan_item_inserted = 1;
2112 #endif
2113 }
2114
2115 enum btrfs_orphan_cleanup_state {
2116         ORPHAN_CLEANUP_STARTED  = 1,
2117         ORPHAN_CLEANUP_DONE     = 2,
2118 };
2119
2120 /*
2121  * This is called in transaction commmit time. If there are no orphan
2122  * files in the subvolume, it removes orphan item and frees block_rsv
2123  * structure.
2124  */
2125 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
2126                               struct btrfs_root *root)
2127 {
2128         int ret;
2129
2130         if (!list_empty(&root->orphan_list) ||
2131             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
2132                 return;
2133
2134         if (root->orphan_item_inserted &&
2135             btrfs_root_refs(&root->root_item) > 0) {
2136                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
2137                                             root->root_key.objectid);
2138                 BUG_ON(ret);
2139                 root->orphan_item_inserted = 0;
2140         }
2141
2142         if (root->orphan_block_rsv) {
2143                 WARN_ON(root->orphan_block_rsv->size > 0);
2144                 btrfs_free_block_rsv(root, root->orphan_block_rsv);
2145                 root->orphan_block_rsv = NULL;
2146         }
2147 }
2148
2149 /*
2150  * This creates an orphan entry for the given inode in case something goes
2151  * wrong in the middle of an unlink/truncate.
2152  *
2153  * NOTE: caller of this function should reserve 5 units of metadata for
2154  *       this function.
2155  */
2156 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
2157 {
2158         struct btrfs_root *root = BTRFS_I(inode)->root;
2159         struct btrfs_block_rsv *block_rsv = NULL;
2160         int reserve = 0;
2161         int insert = 0;
2162         int ret;
2163
2164         if (!root->orphan_block_rsv) {
2165                 block_rsv = btrfs_alloc_block_rsv(root);
2166                 BUG_ON(!block_rsv);
2167         }
2168
2169         spin_lock(&root->orphan_lock);
2170         if (!root->orphan_block_rsv) {
2171                 root->orphan_block_rsv = block_rsv;
2172         } else if (block_rsv) {
2173                 btrfs_free_block_rsv(root, block_rsv);
2174                 block_rsv = NULL;
2175         }
2176
2177         if (list_empty(&BTRFS_I(inode)->i_orphan)) {
2178                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2179 #if 0
2180                 /*
2181                  * For proper ENOSPC handling, we should do orphan
2182                  * cleanup when mounting. But this introduces backward
2183                  * compatibility issue.
2184                  */
2185                 if (!xchg(&root->orphan_item_inserted, 1))
2186                         insert = 2;
2187                 else
2188                         insert = 1;
2189 #endif
2190                 insert = 1;
2191         } else {
2192                 WARN_ON(!BTRFS_I(inode)->orphan_meta_reserved);
2193         }
2194
2195         if (!BTRFS_I(inode)->orphan_meta_reserved) {
2196                 BTRFS_I(inode)->orphan_meta_reserved = 1;
2197                 reserve = 1;
2198         }
2199         spin_unlock(&root->orphan_lock);
2200
2201         if (block_rsv)
2202                 btrfs_add_durable_block_rsv(root->fs_info, block_rsv);
2203
2204         /* grab metadata reservation from transaction handle */
2205         if (reserve) {
2206                 ret = btrfs_orphan_reserve_metadata(trans, inode);
2207                 BUG_ON(ret);
2208         }
2209
2210         /* insert an orphan item to track this unlinked/truncated file */
2211         if (insert >= 1) {
2212                 ret = btrfs_insert_orphan_item(trans, root, inode->i_ino);
2213                 BUG_ON(ret);
2214         }
2215
2216         /* insert an orphan item to track subvolume contains orphan files */
2217         if (insert >= 2) {
2218                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2219                                                root->root_key.objectid);
2220                 BUG_ON(ret);
2221         }
2222         return 0;
2223 }
2224
2225 /*
2226  * We have done the truncate/delete so we can go ahead and remove the orphan
2227  * item for this particular inode.
2228  */
2229 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode)
2230 {
2231         struct btrfs_root *root = BTRFS_I(inode)->root;
2232         int delete_item = 0;
2233         int release_rsv = 0;
2234         int ret = 0;
2235
2236         spin_lock(&root->orphan_lock);
2237         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
2238                 list_del_init(&BTRFS_I(inode)->i_orphan);
2239                 delete_item = 1;
2240         }
2241
2242         if (BTRFS_I(inode)->orphan_meta_reserved) {
2243                 BTRFS_I(inode)->orphan_meta_reserved = 0;
2244                 release_rsv = 1;
2245         }
2246         spin_unlock(&root->orphan_lock);
2247
2248         if (trans && delete_item) {
2249                 ret = btrfs_del_orphan_item(trans, root, inode->i_ino);
2250                 BUG_ON(ret);
2251         }
2252
2253         if (release_rsv)
2254                 btrfs_orphan_release_metadata(inode);
2255
2256         return 0;
2257 }
2258
2259 /*
2260  * this cleans up any orphans that may be left on the list from the last use
2261  * of this root.
2262  */
2263 void btrfs_orphan_cleanup(struct btrfs_root *root)
2264 {
2265         struct btrfs_path *path;
2266         struct extent_buffer *leaf;
2267         struct btrfs_key key, found_key;
2268         struct btrfs_trans_handle *trans;
2269         struct inode *inode;
2270         int ret = 0, nr_unlink = 0, nr_truncate = 0;
2271
2272         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
2273                 return;
2274
2275         path = btrfs_alloc_path();
2276         BUG_ON(!path);
2277         path->reada = -1;
2278
2279         key.objectid = BTRFS_ORPHAN_OBJECTID;
2280         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
2281         key.offset = (u64)-1;
2282
2283         while (1) {
2284                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2285                 if (ret < 0) {
2286                         printk(KERN_ERR "Error searching slot for orphan: %d"
2287                                "\n", ret);
2288                         break;
2289                 }
2290
2291                 /*
2292                  * if ret == 0 means we found what we were searching for, which
2293                  * is weird, but possible, so only screw with path if we didnt
2294                  * find the key and see if we have stuff that matches
2295                  */
2296                 if (ret > 0) {
2297                         if (path->slots[0] == 0)
2298                                 break;
2299                         path->slots[0]--;
2300                 }
2301
2302                 /* pull out the item */
2303                 leaf = path->nodes[0];
2304                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2305
2306                 /* make sure the item matches what we want */
2307                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
2308                         break;
2309                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
2310                         break;
2311
2312                 /* release the path since we're done with it */
2313                 btrfs_release_path(root, path);
2314
2315                 /*
2316                  * this is where we are basically btrfs_lookup, without the
2317                  * crossing root thing.  we store the inode number in the
2318                  * offset of the orphan item.
2319                  */
2320                 found_key.objectid = found_key.offset;
2321                 found_key.type = BTRFS_INODE_ITEM_KEY;
2322                 found_key.offset = 0;
2323                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
2324                 BUG_ON(IS_ERR(inode));
2325
2326                 /*
2327                  * add this inode to the orphan list so btrfs_orphan_del does
2328                  * the proper thing when we hit it
2329                  */
2330                 spin_lock(&root->orphan_lock);
2331                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2332                 spin_unlock(&root->orphan_lock);
2333
2334                 /*
2335                  * if this is a bad inode, means we actually succeeded in
2336                  * removing the inode, but not the orphan record, which means
2337                  * we need to manually delete the orphan since iput will just
2338                  * do a destroy_inode
2339                  */
2340                 if (is_bad_inode(inode)) {
2341                         trans = btrfs_start_transaction(root, 0);
2342                         btrfs_orphan_del(trans, inode);
2343                         btrfs_end_transaction(trans, root);
2344                         iput(inode);
2345                         continue;
2346                 }
2347
2348                 /* if we have links, this was a truncate, lets do that */
2349                 if (inode->i_nlink) {
2350                         nr_truncate++;
2351                         btrfs_truncate(inode);
2352                 } else {
2353                         nr_unlink++;
2354                 }
2355
2356                 /* this will do delete_inode and everything for us */
2357                 iput(inode);
2358         }
2359         btrfs_free_path(path);
2360
2361         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
2362
2363         if (root->orphan_block_rsv)
2364                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
2365                                         (u64)-1);
2366
2367         if (root->orphan_block_rsv || root->orphan_item_inserted) {
2368                 trans = btrfs_join_transaction(root, 1);
2369                 btrfs_end_transaction(trans, root);
2370         }
2371
2372         if (nr_unlink)
2373                 printk(KERN_INFO "btrfs: unlinked %d orphans\n", nr_unlink);
2374         if (nr_truncate)
2375                 printk(KERN_INFO "btrfs: truncated %d orphans\n", nr_truncate);
2376 }
2377
2378 /*
2379  * very simple check to peek ahead in the leaf looking for xattrs.  If we
2380  * don't find any xattrs, we know there can't be any acls.
2381  *
2382  * slot is the slot the inode is in, objectid is the objectid of the inode
2383  */
2384 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
2385                                           int slot, u64 objectid)
2386 {
2387         u32 nritems = btrfs_header_nritems(leaf);
2388         struct btrfs_key found_key;
2389         int scanned = 0;
2390
2391         slot++;
2392         while (slot < nritems) {
2393                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2394
2395                 /* we found a different objectid, there must not be acls */
2396                 if (found_key.objectid != objectid)
2397                         return 0;
2398
2399                 /* we found an xattr, assume we've got an acl */
2400                 if (found_key.type == BTRFS_XATTR_ITEM_KEY)
2401                         return 1;
2402
2403                 /*
2404                  * we found a key greater than an xattr key, there can't
2405                  * be any acls later on
2406                  */
2407                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
2408                         return 0;
2409
2410                 slot++;
2411                 scanned++;
2412
2413                 /*
2414                  * it goes inode, inode backrefs, xattrs, extents,
2415                  * so if there are a ton of hard links to an inode there can
2416                  * be a lot of backrefs.  Don't waste time searching too hard,
2417                  * this is just an optimization
2418                  */
2419                 if (scanned >= 8)
2420                         break;
2421         }
2422         /* we hit the end of the leaf before we found an xattr or
2423          * something larger than an xattr.  We have to assume the inode
2424          * has acls
2425          */
2426         return 1;
2427 }
2428
2429 /*
2430  * read an inode from the btree into the in-memory inode
2431  */
2432 static void btrfs_read_locked_inode(struct inode *inode)
2433 {
2434         struct btrfs_path *path;
2435         struct extent_buffer *leaf;
2436         struct btrfs_inode_item *inode_item;
2437         struct btrfs_timespec *tspec;
2438         struct btrfs_root *root = BTRFS_I(inode)->root;
2439         struct btrfs_key location;
2440         int maybe_acls;
2441         u64 alloc_group_block;
2442         u32 rdev;
2443         int ret;
2444
2445         path = btrfs_alloc_path();
2446         BUG_ON(!path);
2447         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
2448
2449         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
2450         if (ret)
2451                 goto make_bad;
2452
2453         leaf = path->nodes[0];
2454         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2455                                     struct btrfs_inode_item);
2456
2457         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
2458         inode->i_nlink = btrfs_inode_nlink(leaf, inode_item);
2459         inode->i_uid = btrfs_inode_uid(leaf, inode_item);
2460         inode->i_gid = btrfs_inode_gid(leaf, inode_item);
2461         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
2462
2463         tspec = btrfs_inode_atime(inode_item);
2464         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2465         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2466
2467         tspec = btrfs_inode_mtime(inode_item);
2468         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2469         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2470
2471         tspec = btrfs_inode_ctime(inode_item);
2472         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2473         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2474
2475         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
2476         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
2477         BTRFS_I(inode)->sequence = btrfs_inode_sequence(leaf, inode_item);
2478         inode->i_generation = BTRFS_I(inode)->generation;
2479         inode->i_rdev = 0;
2480         rdev = btrfs_inode_rdev(leaf, inode_item);
2481
2482         BTRFS_I(inode)->index_cnt = (u64)-1;
2483         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
2484
2485         alloc_group_block = btrfs_inode_block_group(leaf, inode_item);
2486
2487         /*
2488          * try to precache a NULL acl entry for files that don't have
2489          * any xattrs or acls
2490          */
2491         maybe_acls = acls_after_inode_item(leaf, path->slots[0], inode->i_ino);
2492         if (!maybe_acls)
2493                 cache_no_acl(inode);
2494
2495         BTRFS_I(inode)->block_group = btrfs_find_block_group(root, 0,
2496                                                 alloc_group_block, 0);
2497         btrfs_free_path(path);
2498         inode_item = NULL;
2499
2500         switch (inode->i_mode & S_IFMT) {
2501         case S_IFREG:
2502                 inode->i_mapping->a_ops = &btrfs_aops;
2503                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2504                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
2505                 inode->i_fop = &btrfs_file_operations;
2506                 inode->i_op = &btrfs_file_inode_operations;
2507                 break;
2508         case S_IFDIR:
2509                 inode->i_fop = &btrfs_dir_file_operations;
2510                 if (root == root->fs_info->tree_root)
2511                         inode->i_op = &btrfs_dir_ro_inode_operations;
2512                 else
2513                         inode->i_op = &btrfs_dir_inode_operations;
2514                 break;
2515         case S_IFLNK:
2516                 inode->i_op = &btrfs_symlink_inode_operations;
2517                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
2518                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2519                 break;
2520         default:
2521                 inode->i_op = &btrfs_special_inode_operations;
2522                 init_special_inode(inode, inode->i_mode, rdev);
2523                 break;
2524         }
2525
2526         btrfs_update_iflags(inode);
2527         return;
2528
2529 make_bad:
2530         btrfs_free_path(path);
2531         make_bad_inode(inode);
2532 }
2533
2534 /*
2535  * given a leaf and an inode, copy the inode fields into the leaf
2536  */
2537 static void fill_inode_item(struct btrfs_trans_handle *trans,
2538                             struct extent_buffer *leaf,
2539                             struct btrfs_inode_item *item,
2540                             struct inode *inode)
2541 {
2542         btrfs_set_inode_uid(leaf, item, inode->i_uid);
2543         btrfs_set_inode_gid(leaf, item, inode->i_gid);
2544         btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
2545         btrfs_set_inode_mode(leaf, item, inode->i_mode);
2546         btrfs_set_inode_nlink(leaf, item, inode->i_nlink);
2547
2548         btrfs_set_timespec_sec(leaf, btrfs_inode_atime(item),
2549                                inode->i_atime.tv_sec);
2550         btrfs_set_timespec_nsec(leaf, btrfs_inode_atime(item),
2551                                 inode->i_atime.tv_nsec);
2552
2553         btrfs_set_timespec_sec(leaf, btrfs_inode_mtime(item),
2554                                inode->i_mtime.tv_sec);
2555         btrfs_set_timespec_nsec(leaf, btrfs_inode_mtime(item),
2556                                 inode->i_mtime.tv_nsec);
2557
2558         btrfs_set_timespec_sec(leaf, btrfs_inode_ctime(item),
2559                                inode->i_ctime.tv_sec);
2560         btrfs_set_timespec_nsec(leaf, btrfs_inode_ctime(item),
2561                                 inode->i_ctime.tv_nsec);
2562
2563         btrfs_set_inode_nbytes(leaf, item, inode_get_bytes(inode));
2564         btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
2565         btrfs_set_inode_sequence(leaf, item, BTRFS_I(inode)->sequence);
2566         btrfs_set_inode_transid(leaf, item, trans->transid);
2567         btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
2568         btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
2569         btrfs_set_inode_block_group(leaf, item, BTRFS_I(inode)->block_group);
2570 }
2571
2572 /*
2573  * copy everything in the in-memory inode into the btree.
2574  */
2575 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
2576                                 struct btrfs_root *root, struct inode *inode)
2577 {
2578         struct btrfs_inode_item *inode_item;
2579         struct btrfs_path *path;
2580         struct extent_buffer *leaf;
2581         int ret;
2582
2583         path = btrfs_alloc_path();
2584         BUG_ON(!path);
2585         path->leave_spinning = 1;
2586         ret = btrfs_lookup_inode(trans, root, path,
2587                                  &BTRFS_I(inode)->location, 1);
2588         if (ret) {
2589                 if (ret > 0)
2590                         ret = -ENOENT;
2591                 goto failed;
2592         }
2593
2594         btrfs_unlock_up_safe(path, 1);
2595         leaf = path->nodes[0];
2596         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2597                                   struct btrfs_inode_item);
2598
2599         fill_inode_item(trans, leaf, inode_item, inode);
2600         btrfs_mark_buffer_dirty(leaf);
2601         btrfs_set_inode_last_trans(trans, inode);
2602         ret = 0;
2603 failed:
2604         btrfs_free_path(path);
2605         return ret;
2606 }
2607
2608
2609 /*
2610  * unlink helper that gets used here in inode.c and in the tree logging
2611  * recovery code.  It remove a link in a directory with a given name, and
2612  * also drops the back refs in the inode to the directory
2613  */
2614 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2615                        struct btrfs_root *root,
2616                        struct inode *dir, struct inode *inode,
2617                        const char *name, int name_len)
2618 {
2619         struct btrfs_path *path;
2620         int ret = 0;
2621         struct extent_buffer *leaf;
2622         struct btrfs_dir_item *di;
2623         struct btrfs_key key;
2624         u64 index;
2625
2626         path = btrfs_alloc_path();
2627         if (!path) {
2628                 ret = -ENOMEM;
2629                 goto err;
2630         }
2631
2632         path->leave_spinning = 1;
2633         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
2634                                     name, name_len, -1);
2635         if (IS_ERR(di)) {
2636                 ret = PTR_ERR(di);
2637                 goto err;
2638         }
2639         if (!di) {
2640                 ret = -ENOENT;
2641                 goto err;
2642         }
2643         leaf = path->nodes[0];
2644         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2645         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2646         if (ret)
2647                 goto err;
2648         btrfs_release_path(root, path);
2649
2650         ret = btrfs_del_inode_ref(trans, root, name, name_len,
2651                                   inode->i_ino,
2652                                   dir->i_ino, &index);
2653         if (ret) {
2654                 printk(KERN_INFO "btrfs failed to delete reference to %.*s, "
2655                        "inode %lu parent %lu\n", name_len, name,
2656                        inode->i_ino, dir->i_ino);
2657                 goto err;
2658         }
2659
2660         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
2661                                          index, name, name_len, -1);
2662         if (IS_ERR(di)) {
2663                 ret = PTR_ERR(di);
2664                 goto err;
2665         }
2666         if (!di) {
2667                 ret = -ENOENT;
2668                 goto err;
2669         }
2670         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2671         btrfs_release_path(root, path);
2672
2673         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
2674                                          inode, dir->i_ino);
2675         BUG_ON(ret != 0 && ret != -ENOENT);
2676
2677         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
2678                                            dir, index);
2679         if (ret == -ENOENT)
2680                 ret = 0;
2681 err:
2682         btrfs_free_path(path);
2683         if (ret)
2684                 goto out;
2685
2686         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2687         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2688         btrfs_update_inode(trans, root, dir);
2689         btrfs_drop_nlink(inode);
2690         ret = btrfs_update_inode(trans, root, inode);
2691 out:
2692         return ret;
2693 }
2694
2695 /* helper to check if there is any shared block in the path */
2696 static int check_path_shared(struct btrfs_root *root,
2697                              struct btrfs_path *path)
2698 {
2699         struct extent_buffer *eb;
2700         int level;
2701         u64 refs = 1;
2702         int uninitialized_var(ret);
2703
2704         for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2705                 if (!path->nodes[level])
2706                         break;
2707                 eb = path->nodes[level];
2708                 if (!btrfs_block_can_be_shared(root, eb))
2709                         continue;
2710                 ret = btrfs_lookup_extent_info(NULL, root, eb->start, eb->len,
2711                                                &refs, NULL);
2712                 if (refs > 1)
2713                         return 1;
2714         }
2715         return ret; /* XXX callers? */
2716 }
2717
2718 /*
2719  * helper to start transaction for unlink and rmdir.
2720  *
2721  * unlink and rmdir are special in btrfs, they do not always free space.
2722  * so in enospc case, we should make sure they will free space before
2723  * allowing them to use the global metadata reservation.
2724  */
2725 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
2726                                                        struct dentry *dentry)
2727 {
2728         struct btrfs_trans_handle *trans;
2729         struct btrfs_root *root = BTRFS_I(dir)->root;
2730         struct btrfs_path *path;
2731         struct btrfs_inode_ref *ref;
2732         struct btrfs_dir_item *di;
2733         struct inode *inode = dentry->d_inode;
2734         u64 index;
2735         int check_link = 1;
2736         int err = -ENOSPC;
2737         int ret;
2738
2739         trans = btrfs_start_transaction(root, 10);
2740         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
2741                 return trans;
2742
2743         if (inode->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
2744                 return ERR_PTR(-ENOSPC);
2745
2746         /* check if there is someone else holds reference */
2747         if (S_ISDIR(inode->i_mode) && atomic_read(&inode->i_count) > 1)
2748                 return ERR_PTR(-ENOSPC);
2749
2750         if (atomic_read(&inode->i_count) > 2)
2751                 return ERR_PTR(-ENOSPC);
2752
2753         if (xchg(&root->fs_info->enospc_unlink, 1))
2754                 return ERR_PTR(-ENOSPC);
2755
2756         path = btrfs_alloc_path();
2757         if (!path) {
2758                 root->fs_info->enospc_unlink = 0;
2759                 return ERR_PTR(-ENOMEM);
2760         }
2761
2762         trans = btrfs_start_transaction(root, 0);
2763         if (IS_ERR(trans)) {
2764                 btrfs_free_path(path);
2765                 root->fs_info->enospc_unlink = 0;
2766                 return trans;
2767         }
2768
2769         path->skip_locking = 1;
2770         path->search_commit_root = 1;
2771
2772         ret = btrfs_lookup_inode(trans, root, path,
2773                                 &BTRFS_I(dir)->location, 0);
2774         if (ret < 0) {
2775                 err = ret;
2776                 goto out;
2777         }
2778         if (ret == 0) {
2779                 if (check_path_shared(root, path))
2780                         goto out;
2781         } else {
2782                 check_link = 0;
2783         }
2784         btrfs_release_path(root, path);
2785
2786         ret = btrfs_lookup_inode(trans, root, path,
2787                                 &BTRFS_I(inode)->location, 0);
2788         if (ret < 0) {
2789                 err = ret;
2790                 goto out;
2791         }
2792         if (ret == 0) {
2793                 if (check_path_shared(root, path))
2794                         goto out;
2795         } else {
2796                 check_link = 0;
2797         }
2798         btrfs_release_path(root, path);
2799
2800         if (ret == 0 && S_ISREG(inode->i_mode)) {
2801                 ret = btrfs_lookup_file_extent(trans, root, path,
2802                                                inode->i_ino, (u64)-1, 0);
2803                 if (ret < 0) {
2804                         err = ret;
2805                         goto out;
2806                 }
2807                 BUG_ON(ret == 0);
2808                 if (check_path_shared(root, path))
2809                         goto out;
2810                 btrfs_release_path(root, path);
2811         }
2812
2813         if (!check_link) {
2814                 err = 0;
2815                 goto out;
2816         }
2817
2818         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
2819                                 dentry->d_name.name, dentry->d_name.len, 0);
2820         if (IS_ERR(di)) {
2821                 err = PTR_ERR(di);
2822                 goto out;
2823         }
2824         if (di) {
2825                 if (check_path_shared(root, path))
2826                         goto out;
2827         } else {
2828                 err = 0;
2829                 goto out;
2830         }
2831         btrfs_release_path(root, path);
2832
2833         ref = btrfs_lookup_inode_ref(trans, root, path,
2834                                 dentry->d_name.name, dentry->d_name.len,
2835                                 inode->i_ino, dir->i_ino, 0);
2836         if (IS_ERR(ref)) {
2837                 err = PTR_ERR(ref);
2838                 goto out;
2839         }
2840         BUG_ON(!ref);
2841         if (check_path_shared(root, path))
2842                 goto out;
2843         index = btrfs_inode_ref_index(path->nodes[0], ref);
2844         btrfs_release_path(root, path);
2845
2846         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino, index,
2847                                 dentry->d_name.name, dentry->d_name.len, 0);
2848         if (IS_ERR(di)) {
2849                 err = PTR_ERR(di);
2850                 goto out;
2851         }
2852         BUG_ON(ret == -ENOENT);
2853         if (check_path_shared(root, path))
2854                 goto out;
2855
2856         err = 0;
2857 out:
2858         btrfs_free_path(path);
2859         if (err) {
2860                 btrfs_end_transaction(trans, root);
2861                 root->fs_info->enospc_unlink = 0;
2862                 return ERR_PTR(err);
2863         }
2864
2865         trans->block_rsv = &root->fs_info->global_block_rsv;
2866         return trans;
2867 }
2868
2869 static void __unlink_end_trans(struct btrfs_trans_handle *trans,
2870                                struct btrfs_root *root)
2871 {
2872         if (trans->block_rsv == &root->fs_info->global_block_rsv) {
2873                 BUG_ON(!root->fs_info->enospc_unlink);
2874                 root->fs_info->enospc_unlink = 0;
2875         }
2876         btrfs_end_transaction_throttle(trans, root);
2877 }
2878
2879 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
2880 {
2881         struct btrfs_root *root = BTRFS_I(dir)->root;
2882         struct btrfs_trans_handle *trans;
2883         struct inode *inode = dentry->d_inode;
2884         int ret;
2885         unsigned long nr = 0;
2886
2887         trans = __unlink_start_trans(dir, dentry);
2888         if (IS_ERR(trans))
2889                 return PTR_ERR(trans);
2890
2891         btrfs_set_trans_block_group(trans, dir);
2892
2893         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
2894
2895         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
2896                                  dentry->d_name.name, dentry->d_name.len);
2897         BUG_ON(ret);
2898
2899         if (inode->i_nlink == 0) {
2900                 ret = btrfs_orphan_add(trans, inode);
2901                 BUG_ON(ret);
2902         }
2903
2904         nr = trans->blocks_used;
2905         __unlink_end_trans(trans, root);
2906         btrfs_btree_balance_dirty(root, nr);
2907         return ret;
2908 }
2909
2910 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
2911                         struct btrfs_root *root,
2912                         struct inode *dir, u64 objectid,
2913                         const char *name, int name_len)
2914 {
2915         struct btrfs_path *path;
2916         struct extent_buffer *leaf;
2917         struct btrfs_dir_item *di;
2918         struct btrfs_key key;
2919         u64 index;
2920         int ret;
2921
2922         path = btrfs_alloc_path();
2923         if (!path)
2924                 return -ENOMEM;
2925
2926         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
2927                                    name, name_len, -1);
2928         BUG_ON(!di || IS_ERR(di));
2929
2930         leaf = path->nodes[0];
2931         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2932         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
2933         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2934         BUG_ON(ret);
2935         btrfs_release_path(root, path);
2936
2937         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
2938                                  objectid, root->root_key.objectid,
2939                                  dir->i_ino, &index, name, name_len);
2940         if (ret < 0) {
2941                 BUG_ON(ret != -ENOENT);
2942                 di = btrfs_search_dir_index_item(root, path, dir->i_ino,
2943                                                  name, name_len);
2944                 BUG_ON(!di || IS_ERR(di));
2945
2946                 leaf = path->nodes[0];
2947                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2948                 btrfs_release_path(root, path);
2949                 index = key.offset;
2950         }
2951
2952         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
2953                                          index, name, name_len, -1);
2954         BUG_ON(!di || IS_ERR(di));
2955
2956         leaf = path->nodes[0];
2957         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2958         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
2959         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2960         BUG_ON(ret);
2961         btrfs_release_path(root, path);
2962
2963         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2964         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2965         ret = btrfs_update_inode(trans, root, dir);
2966         BUG_ON(ret);
2967
2968         btrfs_free_path(path);
2969         return 0;
2970 }
2971
2972 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
2973 {
2974         struct inode *inode = dentry->d_inode;
2975         int err = 0;
2976         struct btrfs_root *root = BTRFS_I(dir)->root;
2977         struct btrfs_trans_handle *trans;
2978         unsigned long nr = 0;
2979
2980         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
2981             inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
2982                 return -ENOTEMPTY;
2983
2984         trans = __unlink_start_trans(dir, dentry);
2985         if (IS_ERR(trans))
2986                 return PTR_ERR(trans);
2987
2988         btrfs_set_trans_block_group(trans, dir);
2989
2990         if (unlikely(inode->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
2991                 err = btrfs_unlink_subvol(trans, root, dir,
2992                                           BTRFS_I(inode)->location.objectid,
2993                                           dentry->d_name.name,
2994                                           dentry->d_name.len);
2995                 goto out;
2996         }
2997
2998         err = btrfs_orphan_add(trans, inode);
2999         if (err)
3000                 goto out;
3001
3002         /* now the directory is empty */
3003         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3004                                  dentry->d_name.name, dentry->d_name.len);
3005         if (!err)
3006                 btrfs_i_size_write(inode, 0);
3007 out:
3008         nr = trans->blocks_used;
3009         __unlink_end_trans(trans, root);
3010         btrfs_btree_balance_dirty(root, nr);
3011
3012         return err;
3013 }
3014
3015 #if 0
3016 /*
3017  * when truncating bytes in a file, it is possible to avoid reading
3018  * the leaves that contain only checksum items.  This can be the
3019  * majority of the IO required to delete a large file, but it must
3020  * be done carefully.
3021  *
3022  * The keys in the level just above the leaves are checked to make sure
3023  * the lowest key in a given leaf is a csum key, and starts at an offset
3024  * after the new  size.
3025  *
3026  * Then the key for the next leaf is checked to make sure it also has
3027  * a checksum item for the same file.  If it does, we know our target leaf
3028  * contains only checksum items, and it can be safely freed without reading
3029  * it.
3030  *
3031  * This is just an optimization targeted at large files.  It may do
3032  * nothing.  It will return 0 unless things went badly.
3033  */
3034 static noinline int drop_csum_leaves(struct btrfs_trans_handle *trans,
3035                                      struct btrfs_root *root,
3036                                      struct btrfs_path *path,
3037                                      struct inode *inode, u64 new_size)
3038 {
3039         struct btrfs_key key;
3040         int ret;
3041         int nritems;
3042         struct btrfs_key found_key;
3043         struct btrfs_key other_key;
3044         struct btrfs_leaf_ref *ref;
3045         u64 leaf_gen;
3046         u64 leaf_start;
3047
3048         path->lowest_level = 1;
3049         key.objectid = inode->i_ino;
3050         key.type = BTRFS_CSUM_ITEM_KEY;
3051         key.offset = new_size;
3052 again:
3053         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3054         if (ret < 0)
3055                 goto out;
3056
3057         if (path->nodes[1] == NULL) {
3058                 ret = 0;
3059                 goto out;
3060         }
3061         ret = 0;
3062         btrfs_node_key_to_cpu(path->nodes[1], &found_key, path->slots[1]);
3063         nritems = btrfs_header_nritems(path->nodes[1]);
3064
3065         if (!nritems)
3066                 goto out;
3067
3068         if (path->slots[1] >= nritems)
3069                 goto next_node;
3070
3071         /* did we find a key greater than anything we want to delete? */
3072         if (found_key.objectid > inode->i_ino ||
3073            (found_key.objectid == inode->i_ino && found_key.type > key.type))
3074                 goto out;
3075
3076         /* we check the next key in the node to make sure the leave contains
3077          * only checksum items.  This comparison doesn't work if our
3078          * leaf is the last one in the node
3079          */
3080         if (path->slots[1] + 1 >= nritems) {
3081 next_node:
3082                 /* search forward from the last key in the node, this
3083                  * will bring us into the next node in the tree
3084                  */
3085                 btrfs_node_key_to_cpu(path->nodes[1], &found_key, nritems - 1);
3086
3087                 /* unlikely, but we inc below, so check to be safe */
3088                 if (found_key.offset == (u64)-1)
3089                         goto out;
3090
3091                 /* search_forward needs a path with locks held, do the
3092                  * search again for the original key.  It is possible
3093                  * this will race with a balance and return a path that
3094                  * we could modify, but this drop is just an optimization
3095                  * and is allowed to miss some leaves.
3096                  */
3097                 btrfs_release_path(root, path);
3098                 found_key.offset++;
3099
3100                 /* setup a max key for search_forward */
3101                 other_key.offset = (u64)-1;
3102                 other_key.type = key.type;
3103                 other_key.objectid = key.objectid;
3104
3105                 path->keep_locks = 1;
3106                 ret = btrfs_search_forward(root, &found_key, &other_key,
3107                                            path, 0, 0);
3108                 path->keep_locks = 0;
3109                 if (ret || found_key.objectid != key.objectid ||
3110                     found_key.type != key.type) {
3111                         ret = 0;
3112                         goto out;
3113                 }
3114
3115                 key.offset = found_key.offset;
3116                 btrfs_release_path(root, path);
3117                 cond_resched();
3118                 goto again;
3119         }
3120
3121         /* we know there's one more slot after us in the tree,
3122          * read that key so we can verify it is also a checksum item
3123          */
3124         btrfs_node_key_to_cpu(path->nodes[1], &other_key, path->slots[1] + 1);
3125
3126         if (found_key.objectid < inode->i_ino)
3127                 goto next_key;
3128
3129         if (found_key.type != key.type || found_key.offset < new_size)
3130                 goto next_key;
3131
3132         /*
3133          * if the key for the next leaf isn't a csum key from this objectid,
3134          * we can't be sure there aren't good items inside this leaf.
3135          * Bail out
3136          */
3137         if (other_key.objectid != inode->i_ino || other_key.type != key.type)
3138                 goto out;
3139
3140         leaf_start = btrfs_node_blockptr(path->nodes[1], path->slots[1]);
3141         leaf_gen = btrfs_node_ptr_generation(path->nodes[1], path->slots[1]);
3142         /*
3143          * it is safe to delete this leaf, it contains only
3144          * csum items from this inode at an offset >= new_size
3145          */
3146         ret = btrfs_del_leaf(trans, root, path, leaf_start);
3147         BUG_ON(ret);
3148
3149         if (root->ref_cows && leaf_gen < trans->transid) {
3150                 ref = btrfs_alloc_leaf_ref(root, 0);
3151                 if (ref) {
3152                         ref->root_gen = root->root_key.offset;
3153                         ref->bytenr = leaf_start;
3154                         ref->owner = 0;
3155                         ref->generation = leaf_gen;
3156                         ref->nritems = 0;
3157
3158                         btrfs_sort_leaf_ref(ref);
3159
3160                         ret = btrfs_add_leaf_ref(root, ref, 0);
3161                         WARN_ON(ret);
3162                         btrfs_free_leaf_ref(root, ref);
3163                 } else {
3164                         WARN_ON(1);
3165                 }
3166         }
3167 next_key:
3168         btrfs_release_path(root, path);
3169
3170         if (other_key.objectid == inode->i_ino &&
3171             other_key.type == key.type && other_key.offset > key.offset) {
3172                 key.offset = other_key.offset;
3173                 cond_resched();
3174                 goto again;
3175         }
3176         ret = 0;
3177 out:
3178         /* fixup any changes we've made to the path */
3179         path->lowest_level = 0;
3180         path->keep_locks = 0;
3181         btrfs_release_path(root, path);
3182         return ret;
3183 }
3184
3185 #endif
3186
3187 /*
3188  * this can truncate away extent items, csum items and directory items.
3189  * It starts at a high offset and removes keys until it can't find
3190  * any higher than new_size
3191  *
3192  * csum items that cross the new i_size are truncated to the new size
3193  * as well.
3194  *
3195  * min_type is the minimum key type to truncate down to.  If set to 0, this
3196  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3197  */
3198 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3199                                struct btrfs_root *root,
3200                                struct inode *inode,
3201                                u64 new_size, u32 min_type)
3202 {
3203         struct btrfs_path *path;
3204         struct extent_buffer *leaf;
3205         struct btrfs_file_extent_item *fi;
3206         struct btrfs_key key;
3207         struct btrfs_key found_key;
3208         u64 extent_start = 0;
3209         u64 extent_num_bytes = 0;
3210         u64 extent_offset = 0;
3211         u64 item_end = 0;
3212         u64 mask = root->sectorsize - 1;
3213         u32 found_type = (u8)-1;
3214         int found_extent;
3215         int del_item;
3216         int pending_del_nr = 0;
3217         int pending_del_slot = 0;
3218         int extent_type = -1;
3219         int encoding;
3220         int ret;
3221         int err = 0;
3222
3223         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
3224
3225         if (root->ref_cows || root == root->fs_info->tree_root)
3226                 btrfs_drop_extent_cache(inode, new_size & (~mask), (u64)-1, 0);
3227
3228         path = btrfs_alloc_path();
3229         BUG_ON(!path);
3230         path->reada = -1;
3231
3232         key.objectid = inode->i_ino;
3233         key.offset = (u64)-1;
3234         key.type = (u8)-1;
3235
3236 search_again:
3237         path->leave_spinning = 1;
3238         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3239         if (ret < 0) {
3240                 err = ret;
3241                 goto out;
3242         }
3243
3244         if (ret > 0) {
3245                 /* there are no items in the tree for us to truncate, we're
3246                  * done
3247                  */
3248                 if (path->slots[0] == 0)
3249                         goto out;
3250                 path->slots[0]--;
3251         }
3252
3253         while (1) {
3254                 fi = NULL;
3255                 leaf = path->nodes[0];
3256                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3257                 found_type = btrfs_key_type(&found_key);