btusb bluetooth driver: wait for 'waker' work too before closing
[linux-2.6.git] / fs / btrfs / inode.c
1 /*
2  * Copyright (C) 2007 Oracle.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18
19 #include <linux/kernel.h>
20 #include <linux/bio.h>
21 #include <linux/buffer_head.h>
22 #include <linux/file.h>
23 #include <linux/fs.h>
24 #include <linux/pagemap.h>
25 #include <linux/highmem.h>
26 #include <linux/time.h>
27 #include <linux/init.h>
28 #include <linux/string.h>
29 #include <linux/backing-dev.h>
30 #include <linux/mpage.h>
31 #include <linux/swap.h>
32 #include <linux/writeback.h>
33 #include <linux/statfs.h>
34 #include <linux/compat.h>
35 #include <linux/bit_spinlock.h>
36 #include <linux/xattr.h>
37 #include <linux/posix_acl.h>
38 #include <linux/falloc.h>
39 #include "compat.h"
40 #include "ctree.h"
41 #include "disk-io.h"
42 #include "transaction.h"
43 #include "btrfs_inode.h"
44 #include "ioctl.h"
45 #include "print-tree.h"
46 #include "volumes.h"
47 #include "ordered-data.h"
48 #include "xattr.h"
49 #include "tree-log.h"
50 #include "compression.h"
51 #include "locking.h"
52
53 struct btrfs_iget_args {
54         u64 ino;
55         struct btrfs_root *root;
56 };
57
58 static const struct inode_operations btrfs_dir_inode_operations;
59 static const struct inode_operations btrfs_symlink_inode_operations;
60 static const struct inode_operations btrfs_dir_ro_inode_operations;
61 static const struct inode_operations btrfs_special_inode_operations;
62 static const struct inode_operations btrfs_file_inode_operations;
63 static const struct address_space_operations btrfs_aops;
64 static const struct address_space_operations btrfs_symlink_aops;
65 static const struct file_operations btrfs_dir_file_operations;
66 static struct extent_io_ops btrfs_extent_io_ops;
67
68 static struct kmem_cache *btrfs_inode_cachep;
69 struct kmem_cache *btrfs_trans_handle_cachep;
70 struct kmem_cache *btrfs_transaction_cachep;
71 struct kmem_cache *btrfs_path_cachep;
72
73 #define S_SHIFT 12
74 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
75         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
76         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
77         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
78         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
79         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
80         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
81         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
82 };
83
84 static void btrfs_truncate(struct inode *inode);
85 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end);
86 static noinline int cow_file_range(struct inode *inode,
87                                    struct page *locked_page,
88                                    u64 start, u64 end, int *page_started,
89                                    unsigned long *nr_written, int unlock);
90
91 static int btrfs_init_inode_security(struct inode *inode,  struct inode *dir)
92 {
93         int err;
94
95         err = btrfs_init_acl(inode, dir);
96         if (!err)
97                 err = btrfs_xattr_security_init(inode, dir);
98         return err;
99 }
100
101 /*
102  * this does all the hard work for inserting an inline extent into
103  * the btree.  The caller should have done a btrfs_drop_extents so that
104  * no overlapping inline items exist in the btree
105  */
106 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
107                                 struct btrfs_root *root, struct inode *inode,
108                                 u64 start, size_t size, size_t compressed_size,
109                                 struct page **compressed_pages)
110 {
111         struct btrfs_key key;
112         struct btrfs_path *path;
113         struct extent_buffer *leaf;
114         struct page *page = NULL;
115         char *kaddr;
116         unsigned long ptr;
117         struct btrfs_file_extent_item *ei;
118         int err = 0;
119         int ret;
120         size_t cur_size = size;
121         size_t datasize;
122         unsigned long offset;
123         int use_compress = 0;
124
125         if (compressed_size && compressed_pages) {
126                 use_compress = 1;
127                 cur_size = compressed_size;
128         }
129
130         path = btrfs_alloc_path();
131         if (!path)
132                 return -ENOMEM;
133
134         path->leave_spinning = 1;
135         btrfs_set_trans_block_group(trans, inode);
136
137         key.objectid = inode->i_ino;
138         key.offset = start;
139         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
140         datasize = btrfs_file_extent_calc_inline_size(cur_size);
141
142         inode_add_bytes(inode, size);
143         ret = btrfs_insert_empty_item(trans, root, path, &key,
144                                       datasize);
145         BUG_ON(ret);
146         if (ret) {
147                 err = ret;
148                 goto fail;
149         }
150         leaf = path->nodes[0];
151         ei = btrfs_item_ptr(leaf, path->slots[0],
152                             struct btrfs_file_extent_item);
153         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
154         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
155         btrfs_set_file_extent_encryption(leaf, ei, 0);
156         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
157         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
158         ptr = btrfs_file_extent_inline_start(ei);
159
160         if (use_compress) {
161                 struct page *cpage;
162                 int i = 0;
163                 while (compressed_size > 0) {
164                         cpage = compressed_pages[i];
165                         cur_size = min_t(unsigned long, compressed_size,
166                                        PAGE_CACHE_SIZE);
167
168                         kaddr = kmap_atomic(cpage, KM_USER0);
169                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
170                         kunmap_atomic(kaddr, KM_USER0);
171
172                         i++;
173                         ptr += cur_size;
174                         compressed_size -= cur_size;
175                 }
176                 btrfs_set_file_extent_compression(leaf, ei,
177                                                   BTRFS_COMPRESS_ZLIB);
178         } else {
179                 page = find_get_page(inode->i_mapping,
180                                      start >> PAGE_CACHE_SHIFT);
181                 btrfs_set_file_extent_compression(leaf, ei, 0);
182                 kaddr = kmap_atomic(page, KM_USER0);
183                 offset = start & (PAGE_CACHE_SIZE - 1);
184                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
185                 kunmap_atomic(kaddr, KM_USER0);
186                 page_cache_release(page);
187         }
188         btrfs_mark_buffer_dirty(leaf);
189         btrfs_free_path(path);
190
191         BTRFS_I(inode)->disk_i_size = inode->i_size;
192         btrfs_update_inode(trans, root, inode);
193         return 0;
194 fail:
195         btrfs_free_path(path);
196         return err;
197 }
198
199
200 /*
201  * conditionally insert an inline extent into the file.  This
202  * does the checks required to make sure the data is small enough
203  * to fit as an inline extent.
204  */
205 static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans,
206                                  struct btrfs_root *root,
207                                  struct inode *inode, u64 start, u64 end,
208                                  size_t compressed_size,
209                                  struct page **compressed_pages)
210 {
211         u64 isize = i_size_read(inode);
212         u64 actual_end = min(end + 1, isize);
213         u64 inline_len = actual_end - start;
214         u64 aligned_end = (end + root->sectorsize - 1) &
215                         ~((u64)root->sectorsize - 1);
216         u64 hint_byte;
217         u64 data_len = inline_len;
218         int ret;
219
220         if (compressed_size)
221                 data_len = compressed_size;
222
223         if (start > 0 ||
224             actual_end >= PAGE_CACHE_SIZE ||
225             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
226             (!compressed_size &&
227             (actual_end & (root->sectorsize - 1)) == 0) ||
228             end + 1 < isize ||
229             data_len > root->fs_info->max_inline) {
230                 return 1;
231         }
232
233         ret = btrfs_drop_extents(trans, root, inode, start,
234                                  aligned_end, aligned_end, start,
235                                  &hint_byte, 1);
236         BUG_ON(ret);
237
238         if (isize > actual_end)
239                 inline_len = min_t(u64, isize, actual_end);
240         ret = insert_inline_extent(trans, root, inode, start,
241                                    inline_len, compressed_size,
242                                    compressed_pages);
243         BUG_ON(ret);
244         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
245         return 0;
246 }
247
248 struct async_extent {
249         u64 start;
250         u64 ram_size;
251         u64 compressed_size;
252         struct page **pages;
253         unsigned long nr_pages;
254         struct list_head list;
255 };
256
257 struct async_cow {
258         struct inode *inode;
259         struct btrfs_root *root;
260         struct page *locked_page;
261         u64 start;
262         u64 end;
263         struct list_head extents;
264         struct btrfs_work work;
265 };
266
267 static noinline int add_async_extent(struct async_cow *cow,
268                                      u64 start, u64 ram_size,
269                                      u64 compressed_size,
270                                      struct page **pages,
271                                      unsigned long nr_pages)
272 {
273         struct async_extent *async_extent;
274
275         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
276         async_extent->start = start;
277         async_extent->ram_size = ram_size;
278         async_extent->compressed_size = compressed_size;
279         async_extent->pages = pages;
280         async_extent->nr_pages = nr_pages;
281         list_add_tail(&async_extent->list, &cow->extents);
282         return 0;
283 }
284
285 /*
286  * we create compressed extents in two phases.  The first
287  * phase compresses a range of pages that have already been
288  * locked (both pages and state bits are locked).
289  *
290  * This is done inside an ordered work queue, and the compression
291  * is spread across many cpus.  The actual IO submission is step
292  * two, and the ordered work queue takes care of making sure that
293  * happens in the same order things were put onto the queue by
294  * writepages and friends.
295  *
296  * If this code finds it can't get good compression, it puts an
297  * entry onto the work queue to write the uncompressed bytes.  This
298  * makes sure that both compressed inodes and uncompressed inodes
299  * are written in the same order that pdflush sent them down.
300  */
301 static noinline int compress_file_range(struct inode *inode,
302                                         struct page *locked_page,
303                                         u64 start, u64 end,
304                                         struct async_cow *async_cow,
305                                         int *num_added)
306 {
307         struct btrfs_root *root = BTRFS_I(inode)->root;
308         struct btrfs_trans_handle *trans;
309         u64 num_bytes;
310         u64 orig_start;
311         u64 disk_num_bytes;
312         u64 blocksize = root->sectorsize;
313         u64 actual_end;
314         u64 isize = i_size_read(inode);
315         int ret = 0;
316         struct page **pages = NULL;
317         unsigned long nr_pages;
318         unsigned long nr_pages_ret = 0;
319         unsigned long total_compressed = 0;
320         unsigned long total_in = 0;
321         unsigned long max_compressed = 128 * 1024;
322         unsigned long max_uncompressed = 128 * 1024;
323         int i;
324         int will_compress;
325
326         orig_start = start;
327
328         actual_end = min_t(u64, isize, end + 1);
329 again:
330         will_compress = 0;
331         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
332         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
333
334         /*
335          * we don't want to send crud past the end of i_size through
336          * compression, that's just a waste of CPU time.  So, if the
337          * end of the file is before the start of our current
338          * requested range of bytes, we bail out to the uncompressed
339          * cleanup code that can deal with all of this.
340          *
341          * It isn't really the fastest way to fix things, but this is a
342          * very uncommon corner.
343          */
344         if (actual_end <= start)
345                 goto cleanup_and_bail_uncompressed;
346
347         total_compressed = actual_end - start;
348
349         /* we want to make sure that amount of ram required to uncompress
350          * an extent is reasonable, so we limit the total size in ram
351          * of a compressed extent to 128k.  This is a crucial number
352          * because it also controls how easily we can spread reads across
353          * cpus for decompression.
354          *
355          * We also want to make sure the amount of IO required to do
356          * a random read is reasonably small, so we limit the size of
357          * a compressed extent to 128k.
358          */
359         total_compressed = min(total_compressed, max_uncompressed);
360         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
361         num_bytes = max(blocksize,  num_bytes);
362         disk_num_bytes = num_bytes;
363         total_in = 0;
364         ret = 0;
365
366         /*
367          * we do compression for mount -o compress and when the
368          * inode has not been flagged as nocompress.  This flag can
369          * change at any time if we discover bad compression ratios.
370          */
371         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
372             btrfs_test_opt(root, COMPRESS)) {
373                 WARN_ON(pages);
374                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
375
376                 ret = btrfs_zlib_compress_pages(inode->i_mapping, start,
377                                                 total_compressed, pages,
378                                                 nr_pages, &nr_pages_ret,
379                                                 &total_in,
380                                                 &total_compressed,
381                                                 max_compressed);
382
383                 if (!ret) {
384                         unsigned long offset = total_compressed &
385                                 (PAGE_CACHE_SIZE - 1);
386                         struct page *page = pages[nr_pages_ret - 1];
387                         char *kaddr;
388
389                         /* zero the tail end of the last page, we might be
390                          * sending it down to disk
391                          */
392                         if (offset) {
393                                 kaddr = kmap_atomic(page, KM_USER0);
394                                 memset(kaddr + offset, 0,
395                                        PAGE_CACHE_SIZE - offset);
396                                 kunmap_atomic(kaddr, KM_USER0);
397                         }
398                         will_compress = 1;
399                 }
400         }
401         if (start == 0) {
402                 trans = btrfs_join_transaction(root, 1);
403                 BUG_ON(!trans);
404                 btrfs_set_trans_block_group(trans, inode);
405
406                 /* lets try to make an inline extent */
407                 if (ret || total_in < (actual_end - start)) {
408                         /* we didn't compress the entire range, try
409                          * to make an uncompressed inline extent.
410                          */
411                         ret = cow_file_range_inline(trans, root, inode,
412                                                     start, end, 0, NULL);
413                 } else {
414                         /* try making a compressed inline extent */
415                         ret = cow_file_range_inline(trans, root, inode,
416                                                     start, end,
417                                                     total_compressed, pages);
418                 }
419                 btrfs_end_transaction(trans, root);
420                 if (ret == 0) {
421                         /*
422                          * inline extent creation worked, we don't need
423                          * to create any more async work items.  Unlock
424                          * and free up our temp pages.
425                          */
426                         extent_clear_unlock_delalloc(inode,
427                              &BTRFS_I(inode)->io_tree,
428                              start, end, NULL,
429                              EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
430                              EXTENT_CLEAR_DELALLOC |
431                              EXTENT_CLEAR_ACCOUNTING |
432                              EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK);
433                         ret = 0;
434                         goto free_pages_out;
435                 }
436         }
437
438         if (will_compress) {
439                 /*
440                  * we aren't doing an inline extent round the compressed size
441                  * up to a block size boundary so the allocator does sane
442                  * things
443                  */
444                 total_compressed = (total_compressed + blocksize - 1) &
445                         ~(blocksize - 1);
446
447                 /*
448                  * one last check to make sure the compression is really a
449                  * win, compare the page count read with the blocks on disk
450                  */
451                 total_in = (total_in + PAGE_CACHE_SIZE - 1) &
452                         ~(PAGE_CACHE_SIZE - 1);
453                 if (total_compressed >= total_in) {
454                         will_compress = 0;
455                 } else {
456                         disk_num_bytes = total_compressed;
457                         num_bytes = total_in;
458                 }
459         }
460         if (!will_compress && pages) {
461                 /*
462                  * the compression code ran but failed to make things smaller,
463                  * free any pages it allocated and our page pointer array
464                  */
465                 for (i = 0; i < nr_pages_ret; i++) {
466                         WARN_ON(pages[i]->mapping);
467                         page_cache_release(pages[i]);
468                 }
469                 kfree(pages);
470                 pages = NULL;
471                 total_compressed = 0;
472                 nr_pages_ret = 0;
473
474                 /* flag the file so we don't compress in the future */
475                 BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
476         }
477         if (will_compress) {
478                 *num_added += 1;
479
480                 /* the async work queues will take care of doing actual
481                  * allocation on disk for these compressed pages,
482                  * and will submit them to the elevator.
483                  */
484                 add_async_extent(async_cow, start, num_bytes,
485                                  total_compressed, pages, nr_pages_ret);
486
487                 if (start + num_bytes < end && start + num_bytes < actual_end) {
488                         start += num_bytes;
489                         pages = NULL;
490                         cond_resched();
491                         goto again;
492                 }
493         } else {
494 cleanup_and_bail_uncompressed:
495                 /*
496                  * No compression, but we still need to write the pages in
497                  * the file we've been given so far.  redirty the locked
498                  * page if it corresponds to our extent and set things up
499                  * for the async work queue to run cow_file_range to do
500                  * the normal delalloc dance
501                  */
502                 if (page_offset(locked_page) >= start &&
503                     page_offset(locked_page) <= end) {
504                         __set_page_dirty_nobuffers(locked_page);
505                         /* unlocked later on in the async handlers */
506                 }
507                 add_async_extent(async_cow, start, end - start + 1, 0, NULL, 0);
508                 *num_added += 1;
509         }
510
511 out:
512         return 0;
513
514 free_pages_out:
515         for (i = 0; i < nr_pages_ret; i++) {
516                 WARN_ON(pages[i]->mapping);
517                 page_cache_release(pages[i]);
518         }
519         kfree(pages);
520
521         goto out;
522 }
523
524 /*
525  * phase two of compressed writeback.  This is the ordered portion
526  * of the code, which only gets called in the order the work was
527  * queued.  We walk all the async extents created by compress_file_range
528  * and send them down to the disk.
529  */
530 static noinline int submit_compressed_extents(struct inode *inode,
531                                               struct async_cow *async_cow)
532 {
533         struct async_extent *async_extent;
534         u64 alloc_hint = 0;
535         struct btrfs_trans_handle *trans;
536         struct btrfs_key ins;
537         struct extent_map *em;
538         struct btrfs_root *root = BTRFS_I(inode)->root;
539         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
540         struct extent_io_tree *io_tree;
541         int ret;
542
543         if (list_empty(&async_cow->extents))
544                 return 0;
545
546         trans = btrfs_join_transaction(root, 1);
547
548         while (!list_empty(&async_cow->extents)) {
549                 async_extent = list_entry(async_cow->extents.next,
550                                           struct async_extent, list);
551                 list_del(&async_extent->list);
552
553                 io_tree = &BTRFS_I(inode)->io_tree;
554
555                 /* did the compression code fall back to uncompressed IO? */
556                 if (!async_extent->pages) {
557                         int page_started = 0;
558                         unsigned long nr_written = 0;
559
560                         lock_extent(io_tree, async_extent->start,
561                                     async_extent->start +
562                                     async_extent->ram_size - 1, GFP_NOFS);
563
564                         /* allocate blocks */
565                         cow_file_range(inode, async_cow->locked_page,
566                                        async_extent->start,
567                                        async_extent->start +
568                                        async_extent->ram_size - 1,
569                                        &page_started, &nr_written, 0);
570
571                         /*
572                          * if page_started, cow_file_range inserted an
573                          * inline extent and took care of all the unlocking
574                          * and IO for us.  Otherwise, we need to submit
575                          * all those pages down to the drive.
576                          */
577                         if (!page_started)
578                                 extent_write_locked_range(io_tree,
579                                                   inode, async_extent->start,
580                                                   async_extent->start +
581                                                   async_extent->ram_size - 1,
582                                                   btrfs_get_extent,
583                                                   WB_SYNC_ALL);
584                         kfree(async_extent);
585                         cond_resched();
586                         continue;
587                 }
588
589                 lock_extent(io_tree, async_extent->start,
590                             async_extent->start + async_extent->ram_size - 1,
591                             GFP_NOFS);
592                 /*
593                  * here we're doing allocation and writeback of the
594                  * compressed pages
595                  */
596                 btrfs_drop_extent_cache(inode, async_extent->start,
597                                         async_extent->start +
598                                         async_extent->ram_size - 1, 0);
599
600                 ret = btrfs_reserve_extent(trans, root,
601                                            async_extent->compressed_size,
602                                            async_extent->compressed_size,
603                                            0, alloc_hint,
604                                            (u64)-1, &ins, 1);
605                 BUG_ON(ret);
606                 em = alloc_extent_map(GFP_NOFS);
607                 em->start = async_extent->start;
608                 em->len = async_extent->ram_size;
609                 em->orig_start = em->start;
610
611                 em->block_start = ins.objectid;
612                 em->block_len = ins.offset;
613                 em->bdev = root->fs_info->fs_devices->latest_bdev;
614                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
615                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
616
617                 while (1) {
618                         write_lock(&em_tree->lock);
619                         ret = add_extent_mapping(em_tree, em);
620                         write_unlock(&em_tree->lock);
621                         if (ret != -EEXIST) {
622                                 free_extent_map(em);
623                                 break;
624                         }
625                         btrfs_drop_extent_cache(inode, async_extent->start,
626                                                 async_extent->start +
627                                                 async_extent->ram_size - 1, 0);
628                 }
629
630                 ret = btrfs_add_ordered_extent(inode, async_extent->start,
631                                                ins.objectid,
632                                                async_extent->ram_size,
633                                                ins.offset,
634                                                BTRFS_ORDERED_COMPRESSED);
635                 BUG_ON(ret);
636
637                 btrfs_end_transaction(trans, root);
638
639                 /*
640                  * clear dirty, set writeback and unlock the pages.
641                  */
642                 extent_clear_unlock_delalloc(inode,
643                                 &BTRFS_I(inode)->io_tree,
644                                 async_extent->start,
645                                 async_extent->start +
646                                 async_extent->ram_size - 1,
647                                 NULL, EXTENT_CLEAR_UNLOCK_PAGE |
648                                 EXTENT_CLEAR_UNLOCK |
649                                 EXTENT_CLEAR_DELALLOC |
650                                 EXTENT_CLEAR_DIRTY | EXTENT_SET_WRITEBACK);
651
652                 ret = btrfs_submit_compressed_write(inode,
653                                     async_extent->start,
654                                     async_extent->ram_size,
655                                     ins.objectid,
656                                     ins.offset, async_extent->pages,
657                                     async_extent->nr_pages);
658
659                 BUG_ON(ret);
660                 trans = btrfs_join_transaction(root, 1);
661                 alloc_hint = ins.objectid + ins.offset;
662                 kfree(async_extent);
663                 cond_resched();
664         }
665
666         btrfs_end_transaction(trans, root);
667         return 0;
668 }
669
670 /*
671  * when extent_io.c finds a delayed allocation range in the file,
672  * the call backs end up in this code.  The basic idea is to
673  * allocate extents on disk for the range, and create ordered data structs
674  * in ram to track those extents.
675  *
676  * locked_page is the page that writepage had locked already.  We use
677  * it to make sure we don't do extra locks or unlocks.
678  *
679  * *page_started is set to one if we unlock locked_page and do everything
680  * required to start IO on it.  It may be clean and already done with
681  * IO when we return.
682  */
683 static noinline int cow_file_range(struct inode *inode,
684                                    struct page *locked_page,
685                                    u64 start, u64 end, int *page_started,
686                                    unsigned long *nr_written,
687                                    int unlock)
688 {
689         struct btrfs_root *root = BTRFS_I(inode)->root;
690         struct btrfs_trans_handle *trans;
691         u64 alloc_hint = 0;
692         u64 num_bytes;
693         unsigned long ram_size;
694         u64 disk_num_bytes;
695         u64 cur_alloc_size;
696         u64 blocksize = root->sectorsize;
697         u64 actual_end;
698         u64 isize = i_size_read(inode);
699         struct btrfs_key ins;
700         struct extent_map *em;
701         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
702         int ret = 0;
703
704         trans = btrfs_join_transaction(root, 1);
705         BUG_ON(!trans);
706         btrfs_set_trans_block_group(trans, inode);
707
708         actual_end = min_t(u64, isize, end + 1);
709
710         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
711         num_bytes = max(blocksize,  num_bytes);
712         disk_num_bytes = num_bytes;
713         ret = 0;
714
715         if (start == 0) {
716                 /* lets try to make an inline extent */
717                 ret = cow_file_range_inline(trans, root, inode,
718                                             start, end, 0, NULL);
719                 if (ret == 0) {
720                         extent_clear_unlock_delalloc(inode,
721                                      &BTRFS_I(inode)->io_tree,
722                                      start, end, NULL,
723                                      EXTENT_CLEAR_UNLOCK_PAGE |
724                                      EXTENT_CLEAR_UNLOCK |
725                                      EXTENT_CLEAR_DELALLOC |
726                                      EXTENT_CLEAR_ACCOUNTING |
727                                      EXTENT_CLEAR_DIRTY |
728                                      EXTENT_SET_WRITEBACK |
729                                      EXTENT_END_WRITEBACK);
730                         *nr_written = *nr_written +
731                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
732                         *page_started = 1;
733                         ret = 0;
734                         goto out;
735                 }
736         }
737
738         BUG_ON(disk_num_bytes >
739                btrfs_super_total_bytes(&root->fs_info->super_copy));
740
741
742         read_lock(&BTRFS_I(inode)->extent_tree.lock);
743         em = search_extent_mapping(&BTRFS_I(inode)->extent_tree,
744                                    start, num_bytes);
745         if (em) {
746                 alloc_hint = em->block_start;
747                 free_extent_map(em);
748         }
749         read_unlock(&BTRFS_I(inode)->extent_tree.lock);
750         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
751
752         while (disk_num_bytes > 0) {
753                 unsigned long op;
754
755                 cur_alloc_size = min(disk_num_bytes, root->fs_info->max_extent);
756                 ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
757                                            root->sectorsize, 0, alloc_hint,
758                                            (u64)-1, &ins, 1);
759                 BUG_ON(ret);
760
761                 em = alloc_extent_map(GFP_NOFS);
762                 em->start = start;
763                 em->orig_start = em->start;
764                 ram_size = ins.offset;
765                 em->len = ins.offset;
766
767                 em->block_start = ins.objectid;
768                 em->block_len = ins.offset;
769                 em->bdev = root->fs_info->fs_devices->latest_bdev;
770                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
771
772                 while (1) {
773                         write_lock(&em_tree->lock);
774                         ret = add_extent_mapping(em_tree, em);
775                         write_unlock(&em_tree->lock);
776                         if (ret != -EEXIST) {
777                                 free_extent_map(em);
778                                 break;
779                         }
780                         btrfs_drop_extent_cache(inode, start,
781                                                 start + ram_size - 1, 0);
782                 }
783
784                 cur_alloc_size = ins.offset;
785                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
786                                                ram_size, cur_alloc_size, 0);
787                 BUG_ON(ret);
788
789                 if (root->root_key.objectid ==
790                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
791                         ret = btrfs_reloc_clone_csums(inode, start,
792                                                       cur_alloc_size);
793                         BUG_ON(ret);
794                 }
795
796                 if (disk_num_bytes < cur_alloc_size)
797                         break;
798
799                 /* we're not doing compressed IO, don't unlock the first
800                  * page (which the caller expects to stay locked), don't
801                  * clear any dirty bits and don't set any writeback bits
802                  *
803                  * Do set the Private2 bit so we know this page was properly
804                  * setup for writepage
805                  */
806                 op = unlock ? EXTENT_CLEAR_UNLOCK_PAGE : 0;
807                 op |= EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
808                         EXTENT_SET_PRIVATE2;
809
810                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
811                                              start, start + ram_size - 1,
812                                              locked_page, op);
813                 disk_num_bytes -= cur_alloc_size;
814                 num_bytes -= cur_alloc_size;
815                 alloc_hint = ins.objectid + ins.offset;
816                 start += cur_alloc_size;
817         }
818 out:
819         ret = 0;
820         btrfs_end_transaction(trans, root);
821
822         return ret;
823 }
824
825 /*
826  * work queue call back to started compression on a file and pages
827  */
828 static noinline void async_cow_start(struct btrfs_work *work)
829 {
830         struct async_cow *async_cow;
831         int num_added = 0;
832         async_cow = container_of(work, struct async_cow, work);
833
834         compress_file_range(async_cow->inode, async_cow->locked_page,
835                             async_cow->start, async_cow->end, async_cow,
836                             &num_added);
837         if (num_added == 0)
838                 async_cow->inode = NULL;
839 }
840
841 /*
842  * work queue call back to submit previously compressed pages
843  */
844 static noinline void async_cow_submit(struct btrfs_work *work)
845 {
846         struct async_cow *async_cow;
847         struct btrfs_root *root;
848         unsigned long nr_pages;
849
850         async_cow = container_of(work, struct async_cow, work);
851
852         root = async_cow->root;
853         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
854                 PAGE_CACHE_SHIFT;
855
856         atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
857
858         if (atomic_read(&root->fs_info->async_delalloc_pages) <
859             5 * 1042 * 1024 &&
860             waitqueue_active(&root->fs_info->async_submit_wait))
861                 wake_up(&root->fs_info->async_submit_wait);
862
863         if (async_cow->inode)
864                 submit_compressed_extents(async_cow->inode, async_cow);
865 }
866
867 static noinline void async_cow_free(struct btrfs_work *work)
868 {
869         struct async_cow *async_cow;
870         async_cow = container_of(work, struct async_cow, work);
871         kfree(async_cow);
872 }
873
874 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
875                                 u64 start, u64 end, int *page_started,
876                                 unsigned long *nr_written)
877 {
878         struct async_cow *async_cow;
879         struct btrfs_root *root = BTRFS_I(inode)->root;
880         unsigned long nr_pages;
881         u64 cur_end;
882         int limit = 10 * 1024 * 1042;
883
884         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
885                          1, 0, NULL, GFP_NOFS);
886         while (start < end) {
887                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
888                 async_cow->inode = inode;
889                 async_cow->root = root;
890                 async_cow->locked_page = locked_page;
891                 async_cow->start = start;
892
893                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
894                         cur_end = end;
895                 else
896                         cur_end = min(end, start + 512 * 1024 - 1);
897
898                 async_cow->end = cur_end;
899                 INIT_LIST_HEAD(&async_cow->extents);
900
901                 async_cow->work.func = async_cow_start;
902                 async_cow->work.ordered_func = async_cow_submit;
903                 async_cow->work.ordered_free = async_cow_free;
904                 async_cow->work.flags = 0;
905
906                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
907                         PAGE_CACHE_SHIFT;
908                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
909
910                 btrfs_queue_worker(&root->fs_info->delalloc_workers,
911                                    &async_cow->work);
912
913                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
914                         wait_event(root->fs_info->async_submit_wait,
915                            (atomic_read(&root->fs_info->async_delalloc_pages) <
916                             limit));
917                 }
918
919                 while (atomic_read(&root->fs_info->async_submit_draining) &&
920                       atomic_read(&root->fs_info->async_delalloc_pages)) {
921                         wait_event(root->fs_info->async_submit_wait,
922                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
923                            0));
924                 }
925
926                 *nr_written += nr_pages;
927                 start = cur_end + 1;
928         }
929         *page_started = 1;
930         return 0;
931 }
932
933 static noinline int csum_exist_in_range(struct btrfs_root *root,
934                                         u64 bytenr, u64 num_bytes)
935 {
936         int ret;
937         struct btrfs_ordered_sum *sums;
938         LIST_HEAD(list);
939
940         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
941                                        bytenr + num_bytes - 1, &list);
942         if (ret == 0 && list_empty(&list))
943                 return 0;
944
945         while (!list_empty(&list)) {
946                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
947                 list_del(&sums->list);
948                 kfree(sums);
949         }
950         return 1;
951 }
952
953 /*
954  * when nowcow writeback call back.  This checks for snapshots or COW copies
955  * of the extents that exist in the file, and COWs the file as required.
956  *
957  * If no cow copies or snapshots exist, we write directly to the existing
958  * blocks on disk
959  */
960 static noinline int run_delalloc_nocow(struct inode *inode,
961                                        struct page *locked_page,
962                               u64 start, u64 end, int *page_started, int force,
963                               unsigned long *nr_written)
964 {
965         struct btrfs_root *root = BTRFS_I(inode)->root;
966         struct btrfs_trans_handle *trans;
967         struct extent_buffer *leaf;
968         struct btrfs_path *path;
969         struct btrfs_file_extent_item *fi;
970         struct btrfs_key found_key;
971         u64 cow_start;
972         u64 cur_offset;
973         u64 extent_end;
974         u64 extent_offset;
975         u64 disk_bytenr;
976         u64 num_bytes;
977         int extent_type;
978         int ret;
979         int type;
980         int nocow;
981         int check_prev = 1;
982
983         path = btrfs_alloc_path();
984         BUG_ON(!path);
985         trans = btrfs_join_transaction(root, 1);
986         BUG_ON(!trans);
987
988         cow_start = (u64)-1;
989         cur_offset = start;
990         while (1) {
991                 ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
992                                                cur_offset, 0);
993                 BUG_ON(ret < 0);
994                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
995                         leaf = path->nodes[0];
996                         btrfs_item_key_to_cpu(leaf, &found_key,
997                                               path->slots[0] - 1);
998                         if (found_key.objectid == inode->i_ino &&
999                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1000                                 path->slots[0]--;
1001                 }
1002                 check_prev = 0;
1003 next_slot:
1004                 leaf = path->nodes[0];
1005                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1006                         ret = btrfs_next_leaf(root, path);
1007                         if (ret < 0)
1008                                 BUG_ON(1);
1009                         if (ret > 0)
1010                                 break;
1011                         leaf = path->nodes[0];
1012                 }
1013
1014                 nocow = 0;
1015                 disk_bytenr = 0;
1016                 num_bytes = 0;
1017                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1018
1019                 if (found_key.objectid > inode->i_ino ||
1020                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1021                     found_key.offset > end)
1022                         break;
1023
1024                 if (found_key.offset > cur_offset) {
1025                         extent_end = found_key.offset;
1026                         extent_type = 0;
1027                         goto out_check;
1028                 }
1029
1030                 fi = btrfs_item_ptr(leaf, path->slots[0],
1031                                     struct btrfs_file_extent_item);
1032                 extent_type = btrfs_file_extent_type(leaf, fi);
1033
1034                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1035                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1036                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1037                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1038                         extent_end = found_key.offset +
1039                                 btrfs_file_extent_num_bytes(leaf, fi);
1040                         if (extent_end <= start) {
1041                                 path->slots[0]++;
1042                                 goto next_slot;
1043                         }
1044                         if (disk_bytenr == 0)
1045                                 goto out_check;
1046                         if (btrfs_file_extent_compression(leaf, fi) ||
1047                             btrfs_file_extent_encryption(leaf, fi) ||
1048                             btrfs_file_extent_other_encoding(leaf, fi))
1049                                 goto out_check;
1050                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1051                                 goto out_check;
1052                         if (btrfs_extent_readonly(root, disk_bytenr))
1053                                 goto out_check;
1054                         if (btrfs_cross_ref_exist(trans, root, inode->i_ino,
1055                                                   found_key.offset -
1056                                                   extent_offset, disk_bytenr))
1057                                 goto out_check;
1058                         disk_bytenr += extent_offset;
1059                         disk_bytenr += cur_offset - found_key.offset;
1060                         num_bytes = min(end + 1, extent_end) - cur_offset;
1061                         /*
1062                          * force cow if csum exists in the range.
1063                          * this ensure that csum for a given extent are
1064                          * either valid or do not exist.
1065                          */
1066                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1067                                 goto out_check;
1068                         nocow = 1;
1069                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1070                         extent_end = found_key.offset +
1071                                 btrfs_file_extent_inline_len(leaf, fi);
1072                         extent_end = ALIGN(extent_end, root->sectorsize);
1073                 } else {
1074                         BUG_ON(1);
1075                 }
1076 out_check:
1077                 if (extent_end <= start) {
1078                         path->slots[0]++;
1079                         goto next_slot;
1080                 }
1081                 if (!nocow) {
1082                         if (cow_start == (u64)-1)
1083                                 cow_start = cur_offset;
1084                         cur_offset = extent_end;
1085                         if (cur_offset > end)
1086                                 break;
1087                         path->slots[0]++;
1088                         goto next_slot;
1089                 }
1090
1091                 btrfs_release_path(root, path);
1092                 if (cow_start != (u64)-1) {
1093                         ret = cow_file_range(inode, locked_page, cow_start,
1094                                         found_key.offset - 1, page_started,
1095                                         nr_written, 1);
1096                         BUG_ON(ret);
1097                         cow_start = (u64)-1;
1098                 }
1099
1100                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1101                         struct extent_map *em;
1102                         struct extent_map_tree *em_tree;
1103                         em_tree = &BTRFS_I(inode)->extent_tree;
1104                         em = alloc_extent_map(GFP_NOFS);
1105                         em->start = cur_offset;
1106                         em->orig_start = em->start;
1107                         em->len = num_bytes;
1108                         em->block_len = num_bytes;
1109                         em->block_start = disk_bytenr;
1110                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1111                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1112                         while (1) {
1113                                 write_lock(&em_tree->lock);
1114                                 ret = add_extent_mapping(em_tree, em);
1115                                 write_unlock(&em_tree->lock);
1116                                 if (ret != -EEXIST) {
1117                                         free_extent_map(em);
1118                                         break;
1119                                 }
1120                                 btrfs_drop_extent_cache(inode, em->start,
1121                                                 em->start + em->len - 1, 0);
1122                         }
1123                         type = BTRFS_ORDERED_PREALLOC;
1124                 } else {
1125                         type = BTRFS_ORDERED_NOCOW;
1126                 }
1127
1128                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1129                                                num_bytes, num_bytes, type);
1130                 BUG_ON(ret);
1131
1132                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
1133                                 cur_offset, cur_offset + num_bytes - 1,
1134                                 locked_page, EXTENT_CLEAR_UNLOCK_PAGE |
1135                                 EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
1136                                 EXTENT_SET_PRIVATE2);
1137                 cur_offset = extent_end;
1138                 if (cur_offset > end)
1139                         break;
1140         }
1141         btrfs_release_path(root, path);
1142
1143         if (cur_offset <= end && cow_start == (u64)-1)
1144                 cow_start = cur_offset;
1145         if (cow_start != (u64)-1) {
1146                 ret = cow_file_range(inode, locked_page, cow_start, end,
1147                                      page_started, nr_written, 1);
1148                 BUG_ON(ret);
1149         }
1150
1151         ret = btrfs_end_transaction(trans, root);
1152         BUG_ON(ret);
1153         btrfs_free_path(path);
1154         return 0;
1155 }
1156
1157 /*
1158  * extent_io.c call back to do delayed allocation processing
1159  */
1160 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1161                               u64 start, u64 end, int *page_started,
1162                               unsigned long *nr_written)
1163 {
1164         int ret;
1165         struct btrfs_root *root = BTRFS_I(inode)->root;
1166
1167         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW)
1168                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1169                                          page_started, 1, nr_written);
1170         else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC)
1171                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1172                                          page_started, 0, nr_written);
1173         else if (!btrfs_test_opt(root, COMPRESS))
1174                 ret = cow_file_range(inode, locked_page, start, end,
1175                                       page_started, nr_written, 1);
1176         else
1177                 ret = cow_file_range_async(inode, locked_page, start, end,
1178                                            page_started, nr_written);
1179         return ret;
1180 }
1181
1182 static int btrfs_split_extent_hook(struct inode *inode,
1183                                     struct extent_state *orig, u64 split)
1184 {
1185         struct btrfs_root *root = BTRFS_I(inode)->root;
1186         u64 size;
1187
1188         if (!(orig->state & EXTENT_DELALLOC))
1189                 return 0;
1190
1191         size = orig->end - orig->start + 1;
1192         if (size > root->fs_info->max_extent) {
1193                 u64 num_extents;
1194                 u64 new_size;
1195
1196                 new_size = orig->end - split + 1;
1197                 num_extents = div64_u64(size + root->fs_info->max_extent - 1,
1198                                         root->fs_info->max_extent);
1199
1200                 /*
1201                  * if we break a large extent up then leave oustanding_extents
1202                  * be, since we've already accounted for the large extent.
1203                  */
1204                 if (div64_u64(new_size + root->fs_info->max_extent - 1,
1205                               root->fs_info->max_extent) < num_extents)
1206                         return 0;
1207         }
1208
1209         spin_lock(&BTRFS_I(inode)->accounting_lock);
1210         BTRFS_I(inode)->outstanding_extents++;
1211         spin_unlock(&BTRFS_I(inode)->accounting_lock);
1212
1213         return 0;
1214 }
1215
1216 /*
1217  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1218  * extents so we can keep track of new extents that are just merged onto old
1219  * extents, such as when we are doing sequential writes, so we can properly
1220  * account for the metadata space we'll need.
1221  */
1222 static int btrfs_merge_extent_hook(struct inode *inode,
1223                                    struct extent_state *new,
1224                                    struct extent_state *other)
1225 {
1226         struct btrfs_root *root = BTRFS_I(inode)->root;
1227         u64 new_size, old_size;
1228         u64 num_extents;
1229
1230         /* not delalloc, ignore it */
1231         if (!(other->state & EXTENT_DELALLOC))
1232                 return 0;
1233
1234         old_size = other->end - other->start + 1;
1235         if (new->start < other->start)
1236                 new_size = other->end - new->start + 1;
1237         else
1238                 new_size = new->end - other->start + 1;
1239
1240         /* we're not bigger than the max, unreserve the space and go */
1241         if (new_size <= root->fs_info->max_extent) {
1242                 spin_lock(&BTRFS_I(inode)->accounting_lock);
1243                 BTRFS_I(inode)->outstanding_extents--;
1244                 spin_unlock(&BTRFS_I(inode)->accounting_lock);
1245                 return 0;
1246         }
1247
1248         /*
1249          * If we grew by another max_extent, just return, we want to keep that
1250          * reserved amount.
1251          */
1252         num_extents = div64_u64(old_size + root->fs_info->max_extent - 1,
1253                                 root->fs_info->max_extent);
1254         if (div64_u64(new_size + root->fs_info->max_extent - 1,
1255                       root->fs_info->max_extent) > num_extents)
1256                 return 0;
1257
1258         spin_lock(&BTRFS_I(inode)->accounting_lock);
1259         BTRFS_I(inode)->outstanding_extents--;
1260         spin_unlock(&BTRFS_I(inode)->accounting_lock);
1261
1262         return 0;
1263 }
1264
1265 /*
1266  * extent_io.c set_bit_hook, used to track delayed allocation
1267  * bytes in this file, and to maintain the list of inodes that
1268  * have pending delalloc work to be done.
1269  */
1270 static int btrfs_set_bit_hook(struct inode *inode, u64 start, u64 end,
1271                        unsigned long old, unsigned long bits)
1272 {
1273
1274         /*
1275          * set_bit and clear bit hooks normally require _irqsave/restore
1276          * but in this case, we are only testeing for the DELALLOC
1277          * bit, which is only set or cleared with irqs on
1278          */
1279         if (!(old & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {
1280                 struct btrfs_root *root = BTRFS_I(inode)->root;
1281
1282                 spin_lock(&BTRFS_I(inode)->accounting_lock);
1283                 BTRFS_I(inode)->outstanding_extents++;
1284                 spin_unlock(&BTRFS_I(inode)->accounting_lock);
1285                 btrfs_delalloc_reserve_space(root, inode, end - start + 1);
1286                 spin_lock(&root->fs_info->delalloc_lock);
1287                 BTRFS_I(inode)->delalloc_bytes += end - start + 1;
1288                 root->fs_info->delalloc_bytes += end - start + 1;
1289                 if (list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1290                         list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1291                                       &root->fs_info->delalloc_inodes);
1292                 }
1293                 spin_unlock(&root->fs_info->delalloc_lock);
1294         }
1295         return 0;
1296 }
1297
1298 /*
1299  * extent_io.c clear_bit_hook, see set_bit_hook for why
1300  */
1301 static int btrfs_clear_bit_hook(struct inode *inode,
1302                                 struct extent_state *state, unsigned long bits)
1303 {
1304         /*
1305          * set_bit and clear bit hooks normally require _irqsave/restore
1306          * but in this case, we are only testeing for the DELALLOC
1307          * bit, which is only set or cleared with irqs on
1308          */
1309         if ((state->state & EXTENT_DELALLOC) && (bits & EXTENT_DELALLOC)) {
1310                 struct btrfs_root *root = BTRFS_I(inode)->root;
1311
1312                 if (bits & EXTENT_DO_ACCOUNTING) {
1313                         spin_lock(&BTRFS_I(inode)->accounting_lock);
1314                         BTRFS_I(inode)->outstanding_extents--;
1315                         spin_unlock(&BTRFS_I(inode)->accounting_lock);
1316                         btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
1317                 }
1318
1319                 spin_lock(&root->fs_info->delalloc_lock);
1320                 if (state->end - state->start + 1 >
1321                     root->fs_info->delalloc_bytes) {
1322                         printk(KERN_INFO "btrfs warning: delalloc account "
1323                                "%llu %llu\n",
1324                                (unsigned long long)
1325                                state->end - state->start + 1,
1326                                (unsigned long long)
1327                                root->fs_info->delalloc_bytes);
1328                         btrfs_delalloc_free_space(root, inode, (u64)-1);
1329                         root->fs_info->delalloc_bytes = 0;
1330                         BTRFS_I(inode)->delalloc_bytes = 0;
1331                 } else {
1332                         btrfs_delalloc_free_space(root, inode,
1333                                                   state->end -
1334                                                   state->start + 1);
1335                         root->fs_info->delalloc_bytes -= state->end -
1336                                 state->start + 1;
1337                         BTRFS_I(inode)->delalloc_bytes -= state->end -
1338                                 state->start + 1;
1339                 }
1340                 if (BTRFS_I(inode)->delalloc_bytes == 0 &&
1341                     !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1342                         list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1343                 }
1344                 spin_unlock(&root->fs_info->delalloc_lock);
1345         }
1346         return 0;
1347 }
1348
1349 /*
1350  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1351  * we don't create bios that span stripes or chunks
1352  */
1353 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1354                          size_t size, struct bio *bio,
1355                          unsigned long bio_flags)
1356 {
1357         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1358         struct btrfs_mapping_tree *map_tree;
1359         u64 logical = (u64)bio->bi_sector << 9;
1360         u64 length = 0;
1361         u64 map_length;
1362         int ret;
1363
1364         if (bio_flags & EXTENT_BIO_COMPRESSED)
1365                 return 0;
1366
1367         length = bio->bi_size;
1368         map_tree = &root->fs_info->mapping_tree;
1369         map_length = length;
1370         ret = btrfs_map_block(map_tree, READ, logical,
1371                               &map_length, NULL, 0);
1372
1373         if (map_length < length + size)
1374                 return 1;
1375         return 0;
1376 }
1377
1378 /*
1379  * in order to insert checksums into the metadata in large chunks,
1380  * we wait until bio submission time.   All the pages in the bio are
1381  * checksummed and sums are attached onto the ordered extent record.
1382  *
1383  * At IO completion time the cums attached on the ordered extent record
1384  * are inserted into the btree
1385  */
1386 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1387                                     struct bio *bio, int mirror_num,
1388                                     unsigned long bio_flags)
1389 {
1390         struct btrfs_root *root = BTRFS_I(inode)->root;
1391         int ret = 0;
1392
1393         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1394         BUG_ON(ret);
1395         return 0;
1396 }
1397
1398 /*
1399  * in order to insert checksums into the metadata in large chunks,
1400  * we wait until bio submission time.   All the pages in the bio are
1401  * checksummed and sums are attached onto the ordered extent record.
1402  *
1403  * At IO completion time the cums attached on the ordered extent record
1404  * are inserted into the btree
1405  */
1406 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1407                           int mirror_num, unsigned long bio_flags)
1408 {
1409         struct btrfs_root *root = BTRFS_I(inode)->root;
1410         return btrfs_map_bio(root, rw, bio, mirror_num, 1);
1411 }
1412
1413 /*
1414  * extent_io.c submission hook. This does the right thing for csum calculation
1415  * on write, or reading the csums from the tree before a read
1416  */
1417 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1418                           int mirror_num, unsigned long bio_flags)
1419 {
1420         struct btrfs_root *root = BTRFS_I(inode)->root;
1421         int ret = 0;
1422         int skip_sum;
1423
1424         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1425
1426         ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
1427         BUG_ON(ret);
1428
1429         if (!(rw & (1 << BIO_RW))) {
1430                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1431                         return btrfs_submit_compressed_read(inode, bio,
1432                                                     mirror_num, bio_flags);
1433                 } else if (!skip_sum)
1434                         btrfs_lookup_bio_sums(root, inode, bio, NULL);
1435                 goto mapit;
1436         } else if (!skip_sum) {
1437                 /* csum items have already been cloned */
1438                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1439                         goto mapit;
1440                 /* we're doing a write, do the async checksumming */
1441                 return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1442                                    inode, rw, bio, mirror_num,
1443                                    bio_flags, __btrfs_submit_bio_start,
1444                                    __btrfs_submit_bio_done);
1445         }
1446
1447 mapit:
1448         return btrfs_map_bio(root, rw, bio, mirror_num, 0);
1449 }
1450
1451 /*
1452  * given a list of ordered sums record them in the inode.  This happens
1453  * at IO completion time based on sums calculated at bio submission time.
1454  */
1455 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1456                              struct inode *inode, u64 file_offset,
1457                              struct list_head *list)
1458 {
1459         struct btrfs_ordered_sum *sum;
1460
1461         btrfs_set_trans_block_group(trans, inode);
1462
1463         list_for_each_entry(sum, list, list) {
1464                 btrfs_csum_file_blocks(trans,
1465                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1466         }
1467         return 0;
1468 }
1469
1470 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end)
1471 {
1472         if ((end & (PAGE_CACHE_SIZE - 1)) == 0)
1473                 WARN_ON(1);
1474         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1475                                    GFP_NOFS);
1476 }
1477
1478 /* see btrfs_writepage_start_hook for details on why this is required */
1479 struct btrfs_writepage_fixup {
1480         struct page *page;
1481         struct btrfs_work work;
1482 };
1483
1484 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1485 {
1486         struct btrfs_writepage_fixup *fixup;
1487         struct btrfs_ordered_extent *ordered;
1488         struct page *page;
1489         struct inode *inode;
1490         u64 page_start;
1491         u64 page_end;
1492
1493         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1494         page = fixup->page;
1495 again:
1496         lock_page(page);
1497         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1498                 ClearPageChecked(page);
1499                 goto out_page;
1500         }
1501
1502         inode = page->mapping->host;
1503         page_start = page_offset(page);
1504         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1505
1506         lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end, GFP_NOFS);
1507
1508         /* already ordered? We're done */
1509         if (PagePrivate2(page))
1510                 goto out;
1511
1512         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1513         if (ordered) {
1514                 unlock_extent(&BTRFS_I(inode)->io_tree, page_start,
1515                               page_end, GFP_NOFS);
1516                 unlock_page(page);
1517                 btrfs_start_ordered_extent(inode, ordered, 1);
1518                 goto again;
1519         }
1520
1521         btrfs_set_extent_delalloc(inode, page_start, page_end);
1522         ClearPageChecked(page);
1523 out:
1524         unlock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end, GFP_NOFS);
1525 out_page:
1526         unlock_page(page);
1527         page_cache_release(page);
1528 }
1529
1530 /*
1531  * There are a few paths in the higher layers of the kernel that directly
1532  * set the page dirty bit without asking the filesystem if it is a
1533  * good idea.  This causes problems because we want to make sure COW
1534  * properly happens and the data=ordered rules are followed.
1535  *
1536  * In our case any range that doesn't have the ORDERED bit set
1537  * hasn't been properly setup for IO.  We kick off an async process
1538  * to fix it up.  The async helper will wait for ordered extents, set
1539  * the delalloc bit and make it safe to write the page.
1540  */
1541 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1542 {
1543         struct inode *inode = page->mapping->host;
1544         struct btrfs_writepage_fixup *fixup;
1545         struct btrfs_root *root = BTRFS_I(inode)->root;
1546
1547         /* this page is properly in the ordered list */
1548         if (TestClearPagePrivate2(page))
1549                 return 0;
1550
1551         if (PageChecked(page))
1552                 return -EAGAIN;
1553
1554         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1555         if (!fixup)
1556                 return -EAGAIN;
1557
1558         SetPageChecked(page);
1559         page_cache_get(page);
1560         fixup->work.func = btrfs_writepage_fixup_worker;
1561         fixup->page = page;
1562         btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
1563         return -EAGAIN;
1564 }
1565
1566 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1567                                        struct inode *inode, u64 file_pos,
1568                                        u64 disk_bytenr, u64 disk_num_bytes,
1569                                        u64 num_bytes, u64 ram_bytes,
1570                                        u64 locked_end,
1571                                        u8 compression, u8 encryption,
1572                                        u16 other_encoding, int extent_type)
1573 {
1574         struct btrfs_root *root = BTRFS_I(inode)->root;
1575         struct btrfs_file_extent_item *fi;
1576         struct btrfs_path *path;
1577         struct extent_buffer *leaf;
1578         struct btrfs_key ins;
1579         u64 hint;
1580         int ret;
1581
1582         path = btrfs_alloc_path();
1583         BUG_ON(!path);
1584
1585         path->leave_spinning = 1;
1586
1587         /*
1588          * we may be replacing one extent in the tree with another.
1589          * The new extent is pinned in the extent map, and we don't want
1590          * to drop it from the cache until it is completely in the btree.
1591          *
1592          * So, tell btrfs_drop_extents to leave this extent in the cache.
1593          * the caller is expected to unpin it and allow it to be merged
1594          * with the others.
1595          */
1596         ret = btrfs_drop_extents(trans, root, inode, file_pos,
1597                                  file_pos + num_bytes, locked_end,
1598                                  file_pos, &hint, 0);
1599         BUG_ON(ret);
1600
1601         ins.objectid = inode->i_ino;
1602         ins.offset = file_pos;
1603         ins.type = BTRFS_EXTENT_DATA_KEY;
1604         ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
1605         BUG_ON(ret);
1606         leaf = path->nodes[0];
1607         fi = btrfs_item_ptr(leaf, path->slots[0],
1608                             struct btrfs_file_extent_item);
1609         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1610         btrfs_set_file_extent_type(leaf, fi, extent_type);
1611         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1612         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1613         btrfs_set_file_extent_offset(leaf, fi, 0);
1614         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1615         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1616         btrfs_set_file_extent_compression(leaf, fi, compression);
1617         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1618         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1619
1620         btrfs_unlock_up_safe(path, 1);
1621         btrfs_set_lock_blocking(leaf);
1622
1623         btrfs_mark_buffer_dirty(leaf);
1624
1625         inode_add_bytes(inode, num_bytes);
1626
1627         ins.objectid = disk_bytenr;
1628         ins.offset = disk_num_bytes;
1629         ins.type = BTRFS_EXTENT_ITEM_KEY;
1630         ret = btrfs_alloc_reserved_file_extent(trans, root,
1631                                         root->root_key.objectid,
1632                                         inode->i_ino, file_pos, &ins);
1633         BUG_ON(ret);
1634         btrfs_free_path(path);
1635
1636         return 0;
1637 }
1638
1639 /*
1640  * helper function for btrfs_finish_ordered_io, this
1641  * just reads in some of the csum leaves to prime them into ram
1642  * before we start the transaction.  It limits the amount of btree
1643  * reads required while inside the transaction.
1644  */
1645 static noinline void reada_csum(struct btrfs_root *root,
1646                                 struct btrfs_path *path,
1647                                 struct btrfs_ordered_extent *ordered_extent)
1648 {
1649         struct btrfs_ordered_sum *sum;
1650         u64 bytenr;
1651
1652         sum = list_entry(ordered_extent->list.next, struct btrfs_ordered_sum,
1653                          list);
1654         bytenr = sum->sums[0].bytenr;
1655
1656         /*
1657          * we don't care about the results, the point of this search is
1658          * just to get the btree leaves into ram
1659          */
1660         btrfs_lookup_csum(NULL, root->fs_info->csum_root, path, bytenr, 0);
1661 }
1662
1663 /* as ordered data IO finishes, this gets called so we can finish
1664  * an ordered extent if the range of bytes in the file it covers are
1665  * fully written.
1666  */
1667 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
1668 {
1669         struct btrfs_root *root = BTRFS_I(inode)->root;
1670         struct btrfs_trans_handle *trans;
1671         struct btrfs_ordered_extent *ordered_extent = NULL;
1672         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1673         struct btrfs_path *path;
1674         int compressed = 0;
1675         int ret;
1676
1677         ret = btrfs_dec_test_ordered_pending(inode, start, end - start + 1);
1678         if (!ret)
1679                 return 0;
1680
1681         /*
1682          * before we join the transaction, try to do some of our IO.
1683          * This will limit the amount of IO that we have to do with
1684          * the transaction running.  We're unlikely to need to do any
1685          * IO if the file extents are new, the disk_i_size checks
1686          * covers the most common case.
1687          */
1688         if (start < BTRFS_I(inode)->disk_i_size) {
1689                 path = btrfs_alloc_path();
1690                 if (path) {
1691                         ret = btrfs_lookup_file_extent(NULL, root, path,
1692                                                        inode->i_ino,
1693                                                        start, 0);
1694                         ordered_extent = btrfs_lookup_ordered_extent(inode,
1695                                                                      start);
1696                         if (!list_empty(&ordered_extent->list)) {
1697                                 btrfs_release_path(root, path);
1698                                 reada_csum(root, path, ordered_extent);
1699                         }
1700                         btrfs_free_path(path);
1701                 }
1702         }
1703
1704         trans = btrfs_join_transaction(root, 1);
1705
1706         if (!ordered_extent)
1707                 ordered_extent = btrfs_lookup_ordered_extent(inode, start);
1708         BUG_ON(!ordered_extent);
1709         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags))
1710                 goto nocow;
1711
1712         lock_extent(io_tree, ordered_extent->file_offset,
1713                     ordered_extent->file_offset + ordered_extent->len - 1,
1714                     GFP_NOFS);
1715
1716         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
1717                 compressed = 1;
1718         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1719                 BUG_ON(compressed);
1720                 ret = btrfs_mark_extent_written(trans, root, inode,
1721                                                 ordered_extent->file_offset,
1722                                                 ordered_extent->file_offset +
1723                                                 ordered_extent->len);
1724                 BUG_ON(ret);
1725         } else {
1726                 ret = insert_reserved_file_extent(trans, inode,
1727                                                 ordered_extent->file_offset,
1728                                                 ordered_extent->start,
1729                                                 ordered_extent->disk_len,
1730                                                 ordered_extent->len,
1731                                                 ordered_extent->len,
1732                                                 ordered_extent->file_offset +
1733                                                 ordered_extent->len,
1734                                                 compressed, 0, 0,
1735                                                 BTRFS_FILE_EXTENT_REG);
1736                 unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
1737                                    ordered_extent->file_offset,
1738                                    ordered_extent->len);
1739                 BUG_ON(ret);
1740         }
1741         unlock_extent(io_tree, ordered_extent->file_offset,
1742                     ordered_extent->file_offset + ordered_extent->len - 1,
1743                     GFP_NOFS);
1744 nocow:
1745         add_pending_csums(trans, inode, ordered_extent->file_offset,
1746                           &ordered_extent->list);
1747
1748         mutex_lock(&BTRFS_I(inode)->extent_mutex);
1749         btrfs_ordered_update_i_size(inode, ordered_extent);
1750         btrfs_update_inode(trans, root, inode);
1751         btrfs_remove_ordered_extent(inode, ordered_extent);
1752         mutex_unlock(&BTRFS_I(inode)->extent_mutex);
1753
1754         /* once for us */
1755         btrfs_put_ordered_extent(ordered_extent);
1756         /* once for the tree */
1757         btrfs_put_ordered_extent(ordered_extent);
1758
1759         btrfs_end_transaction(trans, root);
1760         return 0;
1761 }
1762
1763 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
1764                                 struct extent_state *state, int uptodate)
1765 {
1766         ClearPagePrivate2(page);
1767         return btrfs_finish_ordered_io(page->mapping->host, start, end);
1768 }
1769
1770 /*
1771  * When IO fails, either with EIO or csum verification fails, we
1772  * try other mirrors that might have a good copy of the data.  This
1773  * io_failure_record is used to record state as we go through all the
1774  * mirrors.  If another mirror has good data, the page is set up to date
1775  * and things continue.  If a good mirror can't be found, the original
1776  * bio end_io callback is called to indicate things have failed.
1777  */
1778 struct io_failure_record {
1779         struct page *page;
1780         u64 start;
1781         u64 len;
1782         u64 logical;
1783         unsigned long bio_flags;
1784         int last_mirror;
1785 };
1786
1787 static int btrfs_io_failed_hook(struct bio *failed_bio,
1788                          struct page *page, u64 start, u64 end,
1789                          struct extent_state *state)
1790 {
1791         struct io_failure_record *failrec = NULL;
1792         u64 private;
1793         struct extent_map *em;
1794         struct inode *inode = page->mapping->host;
1795         struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
1796         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1797         struct bio *bio;
1798         int num_copies;
1799         int ret;
1800         int rw;
1801         u64 logical;
1802
1803         ret = get_state_private(failure_tree, start, &private);
1804         if (ret) {
1805                 failrec = kmalloc(sizeof(*failrec), GFP_NOFS);
1806                 if (!failrec)
1807                         return -ENOMEM;
1808                 failrec->start = start;
1809                 failrec->len = end - start + 1;
1810                 failrec->last_mirror = 0;
1811                 failrec->bio_flags = 0;
1812
1813                 read_lock(&em_tree->lock);
1814                 em = lookup_extent_mapping(em_tree, start, failrec->len);
1815                 if (em->start > start || em->start + em->len < start) {
1816                         free_extent_map(em);
1817                         em = NULL;
1818                 }
1819                 read_unlock(&em_tree->lock);
1820
1821                 if (!em || IS_ERR(em)) {
1822                         kfree(failrec);
1823                         return -EIO;
1824                 }
1825                 logical = start - em->start;
1826                 logical = em->block_start + logical;
1827                 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
1828                         logical = em->block_start;
1829                         failrec->bio_flags = EXTENT_BIO_COMPRESSED;
1830                 }
1831                 failrec->logical = logical;
1832                 free_extent_map(em);
1833                 set_extent_bits(failure_tree, start, end, EXTENT_LOCKED |
1834                                 EXTENT_DIRTY, GFP_NOFS);
1835                 set_state_private(failure_tree, start,
1836                                  (u64)(unsigned long)failrec);
1837         } else {
1838                 failrec = (struct io_failure_record *)(unsigned long)private;
1839         }
1840         num_copies = btrfs_num_copies(
1841                               &BTRFS_I(inode)->root->fs_info->mapping_tree,
1842                               failrec->logical, failrec->len);
1843         failrec->last_mirror++;
1844         if (!state) {
1845                 spin_lock(&BTRFS_I(inode)->io_tree.lock);
1846                 state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
1847                                                     failrec->start,
1848                                                     EXTENT_LOCKED);
1849                 if (state && state->start != failrec->start)
1850                         state = NULL;
1851                 spin_unlock(&BTRFS_I(inode)->io_tree.lock);
1852         }
1853         if (!state || failrec->last_mirror > num_copies) {
1854                 set_state_private(failure_tree, failrec->start, 0);
1855                 clear_extent_bits(failure_tree, failrec->start,
1856                                   failrec->start + failrec->len - 1,
1857                                   EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
1858                 kfree(failrec);
1859                 return -EIO;
1860         }
1861         bio = bio_alloc(GFP_NOFS, 1);
1862         bio->bi_private = state;
1863         bio->bi_end_io = failed_bio->bi_end_io;
1864         bio->bi_sector = failrec->logical >> 9;
1865         bio->bi_bdev = failed_bio->bi_bdev;
1866         bio->bi_size = 0;
1867
1868         bio_add_page(bio, page, failrec->len, start - page_offset(page));
1869         if (failed_bio->bi_rw & (1 << BIO_RW))
1870                 rw = WRITE;
1871         else
1872                 rw = READ;
1873
1874         BTRFS_I(inode)->io_tree.ops->submit_bio_hook(inode, rw, bio,
1875                                                       failrec->last_mirror,
1876                                                       failrec->bio_flags);
1877         return 0;
1878 }
1879
1880 /*
1881  * each time an IO finishes, we do a fast check in the IO failure tree
1882  * to see if we need to process or clean up an io_failure_record
1883  */
1884 static int btrfs_clean_io_failures(struct inode *inode, u64 start)
1885 {
1886         u64 private;
1887         u64 private_failure;
1888         struct io_failure_record *failure;
1889         int ret;
1890
1891         private = 0;
1892         if (count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
1893                              (u64)-1, 1, EXTENT_DIRTY)) {
1894                 ret = get_state_private(&BTRFS_I(inode)->io_failure_tree,
1895                                         start, &private_failure);
1896                 if (ret == 0) {
1897                         failure = (struct io_failure_record *)(unsigned long)
1898                                    private_failure;
1899                         set_state_private(&BTRFS_I(inode)->io_failure_tree,
1900                                           failure->start, 0);
1901                         clear_extent_bits(&BTRFS_I(inode)->io_failure_tree,
1902                                           failure->start,
1903                                           failure->start + failure->len - 1,
1904                                           EXTENT_DIRTY | EXTENT_LOCKED,
1905                                           GFP_NOFS);
1906                         kfree(failure);
1907                 }
1908         }
1909         return 0;
1910 }
1911
1912 /*
1913  * when reads are done, we need to check csums to verify the data is correct
1914  * if there's a match, we allow the bio to finish.  If not, we go through
1915  * the io_failure_record routines to find good copies
1916  */
1917 static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
1918                                struct extent_state *state)
1919 {
1920         size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
1921         struct inode *inode = page->mapping->host;
1922         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1923         char *kaddr;
1924         u64 private = ~(u32)0;
1925         int ret;
1926         struct btrfs_root *root = BTRFS_I(inode)->root;
1927         u32 csum = ~(u32)0;
1928
1929         if (PageChecked(page)) {
1930                 ClearPageChecked(page);
1931                 goto good;
1932         }
1933
1934         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
1935                 return 0;
1936
1937         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
1938             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
1939                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
1940                                   GFP_NOFS);
1941                 return 0;
1942         }
1943
1944         if (state && state->start == start) {
1945                 private = state->private;
1946                 ret = 0;
1947         } else {
1948                 ret = get_state_private(io_tree, start, &private);
1949         }
1950         kaddr = kmap_atomic(page, KM_USER0);
1951         if (ret)
1952                 goto zeroit;
1953
1954         csum = btrfs_csum_data(root, kaddr + offset, csum,  end - start + 1);
1955         btrfs_csum_final(csum, (char *)&csum);
1956         if (csum != private)
1957                 goto zeroit;
1958
1959         kunmap_atomic(kaddr, KM_USER0);
1960 good:
1961         /* if the io failure tree for this inode is non-empty,
1962          * check to see if we've recovered from a failed IO
1963          */
1964         btrfs_clean_io_failures(inode, start);
1965         return 0;
1966
1967 zeroit:
1968         if (printk_ratelimit()) {
1969                 printk(KERN_INFO "btrfs csum failed ino %lu off %llu csum %u "
1970                        "private %llu\n", page->mapping->host->i_ino,
1971                        (unsigned long long)start, csum,
1972                        (unsigned long long)private);
1973         }
1974         memset(kaddr + offset, 1, end - start + 1);
1975         flush_dcache_page(page);
1976         kunmap_atomic(kaddr, KM_USER0);
1977         if (private == 0)
1978                 return 0;
1979         return -EIO;
1980 }
1981
1982 /*
1983  * This creates an orphan entry for the given inode in case something goes
1984  * wrong in the middle of an unlink/truncate.
1985  */
1986 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
1987 {
1988         struct btrfs_root *root = BTRFS_I(inode)->root;
1989         int ret = 0;
1990
1991         spin_lock(&root->list_lock);
1992
1993         /* already on the orphan list, we're good */
1994         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
1995                 spin_unlock(&root->list_lock);
1996                 return 0;
1997         }
1998
1999         list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2000
2001         spin_unlock(&root->list_lock);
2002
2003         /*
2004          * insert an orphan item to track this unlinked/truncated file
2005          */
2006         ret = btrfs_insert_orphan_item(trans, root, inode->i_ino);
2007
2008         return ret;
2009 }
2010
2011 /*
2012  * We have done the truncate/delete so we can go ahead and remove the orphan
2013  * item for this particular inode.
2014  */
2015 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode)
2016 {
2017         struct btrfs_root *root = BTRFS_I(inode)->root;
2018         int ret = 0;
2019
2020         spin_lock(&root->list_lock);
2021
2022         if (list_empty(&BTRFS_I(inode)->i_orphan)) {
2023                 spin_unlock(&root->list_lock);
2024                 return 0;
2025         }
2026
2027         list_del_init(&BTRFS_I(inode)->i_orphan);
2028         if (!trans) {
2029                 spin_unlock(&root->list_lock);
2030                 return 0;
2031         }
2032
2033         spin_unlock(&root->list_lock);
2034
2035         ret = btrfs_del_orphan_item(trans, root, inode->i_ino);
2036
2037         return ret;
2038 }
2039
2040 /*
2041  * this cleans up any orphans that may be left on the list from the last use
2042  * of this root.
2043  */
2044 void btrfs_orphan_cleanup(struct btrfs_root *root)
2045 {
2046         struct btrfs_path *path;
2047         struct extent_buffer *leaf;
2048         struct btrfs_item *item;
2049         struct btrfs_key key, found_key;
2050         struct btrfs_trans_handle *trans;
2051         struct inode *inode;
2052         int ret = 0, nr_unlink = 0, nr_truncate = 0;
2053
2054         path = btrfs_alloc_path();
2055         if (!path)
2056                 return;
2057         path->reada = -1;
2058
2059         key.objectid = BTRFS_ORPHAN_OBJECTID;
2060         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
2061         key.offset = (u64)-1;
2062
2063
2064         while (1) {
2065                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2066                 if (ret < 0) {
2067                         printk(KERN_ERR "Error searching slot for orphan: %d"
2068                                "\n", ret);
2069                         break;
2070                 }
2071
2072                 /*
2073                  * if ret == 0 means we found what we were searching for, which
2074                  * is weird, but possible, so only screw with path if we didnt
2075                  * find the key and see if we have stuff that matches
2076                  */
2077                 if (ret > 0) {
2078                         if (path->slots[0] == 0)
2079                                 break;
2080                         path->slots[0]--;
2081                 }
2082
2083                 /* pull out the item */
2084                 leaf = path->nodes[0];
2085                 item = btrfs_item_nr(leaf, path->slots[0]);
2086                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2087
2088                 /* make sure the item matches what we want */
2089                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
2090                         break;
2091                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
2092                         break;
2093
2094                 /* release the path since we're done with it */
2095                 btrfs_release_path(root, path);
2096
2097                 /*
2098                  * this is where we are basically btrfs_lookup, without the
2099                  * crossing root thing.  we store the inode number in the
2100                  * offset of the orphan item.
2101                  */
2102                 found_key.objectid = found_key.offset;
2103                 found_key.type = BTRFS_INODE_ITEM_KEY;
2104                 found_key.offset = 0;
2105                 inode = btrfs_iget(root->fs_info->sb, &found_key, root);
2106                 if (IS_ERR(inode))
2107                         break;
2108
2109                 /*
2110                  * add this inode to the orphan list so btrfs_orphan_del does
2111                  * the proper thing when we hit it
2112                  */
2113                 spin_lock(&root->list_lock);
2114                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2115                 spin_unlock(&root->list_lock);
2116
2117                 /*
2118                  * if this is a bad inode, means we actually succeeded in
2119                  * removing the inode, but not the orphan record, which means
2120                  * we need to manually delete the orphan since iput will just
2121                  * do a destroy_inode
2122                  */
2123                 if (is_bad_inode(inode)) {
2124                         trans = btrfs_start_transaction(root, 1);
2125                         btrfs_orphan_del(trans, inode);
2126                         btrfs_end_transaction(trans, root);
2127                         iput(inode);
2128                         continue;
2129                 }
2130
2131                 /* if we have links, this was a truncate, lets do that */
2132                 if (inode->i_nlink) {
2133                         nr_truncate++;
2134                         btrfs_truncate(inode);
2135                 } else {
2136                         nr_unlink++;
2137                 }
2138
2139                 /* this will do delete_inode and everything for us */
2140                 iput(inode);
2141         }
2142
2143         if (nr_unlink)
2144                 printk(KERN_INFO "btrfs: unlinked %d orphans\n", nr_unlink);
2145         if (nr_truncate)
2146                 printk(KERN_INFO "btrfs: truncated %d orphans\n", nr_truncate);
2147
2148         btrfs_free_path(path);
2149 }
2150
2151 /*
2152  * very simple check to peek ahead in the leaf looking for xattrs.  If we
2153  * don't find any xattrs, we know there can't be any acls.
2154  *
2155  * slot is the slot the inode is in, objectid is the objectid of the inode
2156  */
2157 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
2158                                           int slot, u64 objectid)
2159 {
2160         u32 nritems = btrfs_header_nritems(leaf);
2161         struct btrfs_key found_key;
2162         int scanned = 0;
2163
2164         slot++;
2165         while (slot < nritems) {
2166                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2167
2168                 /* we found a different objectid, there must not be acls */
2169                 if (found_key.objectid != objectid)
2170                         return 0;
2171
2172                 /* we found an xattr, assume we've got an acl */
2173                 if (found_key.type == BTRFS_XATTR_ITEM_KEY)
2174                         return 1;
2175
2176                 /*
2177                  * we found a key greater than an xattr key, there can't
2178                  * be any acls later on
2179                  */
2180                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
2181                         return 0;
2182
2183                 slot++;
2184                 scanned++;
2185
2186                 /*
2187                  * it goes inode, inode backrefs, xattrs, extents,
2188                  * so if there are a ton of hard links to an inode there can
2189                  * be a lot of backrefs.  Don't waste time searching too hard,
2190                  * this is just an optimization
2191                  */
2192                 if (scanned >= 8)
2193                         break;
2194         }
2195         /* we hit the end of the leaf before we found an xattr or
2196          * something larger than an xattr.  We have to assume the inode
2197          * has acls
2198          */
2199         return 1;
2200 }
2201
2202 /*
2203  * read an inode from the btree into the in-memory inode
2204  */
2205 static void btrfs_read_locked_inode(struct inode *inode)
2206 {
2207         struct btrfs_path *path;
2208         struct extent_buffer *leaf;
2209         struct btrfs_inode_item *inode_item;
2210         struct btrfs_timespec *tspec;
2211         struct btrfs_root *root = BTRFS_I(inode)->root;
2212         struct btrfs_key location;
2213         int maybe_acls;
2214         u64 alloc_group_block;
2215         u32 rdev;
2216         int ret;
2217
2218         path = btrfs_alloc_path();
2219         BUG_ON(!path);
2220         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
2221
2222         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
2223         if (ret)
2224                 goto make_bad;
2225
2226         leaf = path->nodes[0];
2227         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2228                                     struct btrfs_inode_item);
2229
2230         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
2231         inode->i_nlink = btrfs_inode_nlink(leaf, inode_item);
2232         inode->i_uid = btrfs_inode_uid(leaf, inode_item);
2233         inode->i_gid = btrfs_inode_gid(leaf, inode_item);
2234         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
2235
2236         tspec = btrfs_inode_atime(inode_item);
2237         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2238         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2239
2240         tspec = btrfs_inode_mtime(inode_item);
2241         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2242         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2243
2244         tspec = btrfs_inode_ctime(inode_item);
2245         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2246         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2247
2248         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
2249         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
2250         BTRFS_I(inode)->sequence = btrfs_inode_sequence(leaf, inode_item);
2251         inode->i_generation = BTRFS_I(inode)->generation;
2252         inode->i_rdev = 0;
2253         rdev = btrfs_inode_rdev(leaf, inode_item);
2254
2255         BTRFS_I(inode)->index_cnt = (u64)-1;
2256         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
2257
2258         alloc_group_block = btrfs_inode_block_group(leaf, inode_item);
2259
2260         /*
2261          * try to precache a NULL acl entry for files that don't have
2262          * any xattrs or acls
2263          */
2264         maybe_acls = acls_after_inode_item(leaf, path->slots[0], inode->i_ino);
2265         if (!maybe_acls)
2266                 cache_no_acl(inode);
2267
2268         BTRFS_I(inode)->block_group = btrfs_find_block_group(root, 0,
2269                                                 alloc_group_block, 0);
2270         btrfs_free_path(path);
2271         inode_item = NULL;
2272
2273         switch (inode->i_mode & S_IFMT) {
2274         case S_IFREG:
2275                 inode->i_mapping->a_ops = &btrfs_aops;
2276                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2277                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
2278                 inode->i_fop = &btrfs_file_operations;
2279                 inode->i_op = &btrfs_file_inode_operations;
2280                 break;
2281         case S_IFDIR:
2282                 inode->i_fop = &btrfs_dir_file_operations;
2283                 if (root == root->fs_info->tree_root)
2284                         inode->i_op = &btrfs_dir_ro_inode_operations;
2285                 else
2286                         inode->i_op = &btrfs_dir_inode_operations;
2287                 break;
2288         case S_IFLNK:
2289                 inode->i_op = &btrfs_symlink_inode_operations;
2290                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
2291                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2292                 break;
2293         default:
2294                 inode->i_op = &btrfs_special_inode_operations;
2295                 init_special_inode(inode, inode->i_mode, rdev);
2296                 break;
2297         }
2298
2299         btrfs_update_iflags(inode);
2300         return;
2301
2302 make_bad:
2303         btrfs_free_path(path);
2304         make_bad_inode(inode);
2305 }
2306
2307 /*
2308  * given a leaf and an inode, copy the inode fields into the leaf
2309  */
2310 static void fill_inode_item(struct btrfs_trans_handle *trans,
2311                             struct extent_buffer *leaf,
2312                             struct btrfs_inode_item *item,
2313                             struct inode *inode)
2314 {
2315         btrfs_set_inode_uid(leaf, item, inode->i_uid);
2316         btrfs_set_inode_gid(leaf, item, inode->i_gid);
2317         btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
2318         btrfs_set_inode_mode(leaf, item, inode->i_mode);
2319         btrfs_set_inode_nlink(leaf, item, inode->i_nlink);
2320
2321         btrfs_set_timespec_sec(leaf, btrfs_inode_atime(item),
2322                                inode->i_atime.tv_sec);
2323         btrfs_set_timespec_nsec(leaf, btrfs_inode_atime(item),
2324                                 inode->i_atime.tv_nsec);
2325
2326         btrfs_set_timespec_sec(leaf, btrfs_inode_mtime(item),
2327                                inode->i_mtime.tv_sec);
2328         btrfs_set_timespec_nsec(leaf, btrfs_inode_mtime(item),
2329                                 inode->i_mtime.tv_nsec);
2330
2331         btrfs_set_timespec_sec(leaf, btrfs_inode_ctime(item),
2332                                inode->i_ctime.tv_sec);
2333         btrfs_set_timespec_nsec(leaf, btrfs_inode_ctime(item),
2334                                 inode->i_ctime.tv_nsec);
2335
2336         btrfs_set_inode_nbytes(leaf, item, inode_get_bytes(inode));
2337         btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
2338         btrfs_set_inode_sequence(leaf, item, BTRFS_I(inode)->sequence);
2339         btrfs_set_inode_transid(leaf, item, trans->transid);
2340         btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
2341         btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
2342         btrfs_set_inode_block_group(leaf, item, BTRFS_I(inode)->block_group);
2343 }
2344
2345 /*
2346  * copy everything in the in-memory inode into the btree.
2347  */
2348 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
2349                                 struct btrfs_root *root, struct inode *inode)
2350 {
2351         struct btrfs_inode_item *inode_item;
2352         struct btrfs_path *path;
2353         struct extent_buffer *leaf;
2354         int ret;
2355
2356         path = btrfs_alloc_path();
2357         BUG_ON(!path);
2358         path->leave_spinning = 1;
2359         ret = btrfs_lookup_inode(trans, root, path,
2360                                  &BTRFS_I(inode)->location, 1);
2361         if (ret) {
2362                 if (ret > 0)
2363                         ret = -ENOENT;
2364                 goto failed;
2365         }
2366
2367         btrfs_unlock_up_safe(path, 1);
2368         leaf = path->nodes[0];
2369         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2370                                   struct btrfs_inode_item);
2371
2372         fill_inode_item(trans, leaf, inode_item, inode);
2373         btrfs_mark_buffer_dirty(leaf);
2374         btrfs_set_inode_last_trans(trans, inode);
2375         ret = 0;
2376 failed:
2377         btrfs_free_path(path);
2378         return ret;
2379 }
2380
2381
2382 /*
2383  * unlink helper that gets used here in inode.c and in the tree logging
2384  * recovery code.  It remove a link in a directory with a given name, and
2385  * also drops the back refs in the inode to the directory
2386  */
2387 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2388                        struct btrfs_root *root,
2389                        struct inode *dir, struct inode *inode,
2390                        const char *name, int name_len)
2391 {
2392         struct btrfs_path *path;
2393         int ret = 0;
2394         struct extent_buffer *leaf;
2395         struct btrfs_dir_item *di;
2396         struct btrfs_key key;
2397         u64 index;
2398
2399         path = btrfs_alloc_path();
2400         if (!path) {
2401                 ret = -ENOMEM;
2402                 goto err;
2403         }
2404
2405         path->leave_spinning = 1;
2406         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
2407                                     name, name_len, -1);
2408         if (IS_ERR(di)) {
2409                 ret = PTR_ERR(di);
2410                 goto err;
2411         }
2412         if (!di) {
2413                 ret = -ENOENT;
2414                 goto err;
2415         }
2416         leaf = path->nodes[0];
2417         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2418         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2419         if (ret)
2420                 goto err;
2421         btrfs_release_path(root, path);
2422
2423         ret = btrfs_del_inode_ref(trans, root, name, name_len,
2424                                   inode->i_ino,
2425                                   dir->i_ino, &index);
2426         if (ret) {
2427                 printk(KERN_INFO "btrfs failed to delete reference to %.*s, "
2428                        "inode %lu parent %lu\n", name_len, name,
2429                        inode->i_ino, dir->i_ino);
2430                 goto err;
2431         }
2432
2433         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
2434                                          index, name, name_len, -1);
2435         if (IS_ERR(di)) {
2436                 ret = PTR_ERR(di);
2437                 goto err;
2438         }
2439         if (!di) {
2440                 ret = -ENOENT;
2441                 goto err;
2442         }
2443         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2444         btrfs_release_path(root, path);
2445
2446         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
2447                                          inode, dir->i_ino);
2448         BUG_ON(ret != 0 && ret != -ENOENT);
2449
2450         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
2451                                            dir, index);
2452         BUG_ON(ret);
2453 err:
2454         btrfs_free_path(path);
2455         if (ret)
2456                 goto out;
2457
2458         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2459         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2460         btrfs_update_inode(trans, root, dir);
2461         btrfs_drop_nlink(inode);
2462         ret = btrfs_update_inode(trans, root, inode);
2463 out:
2464         return ret;
2465 }
2466
2467 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
2468 {
2469         struct btrfs_root *root;
2470         struct btrfs_trans_handle *trans;
2471         struct inode *inode = dentry->d_inode;
2472         int ret;
2473         unsigned long nr = 0;
2474
2475         root = BTRFS_I(dir)->root;
2476
2477         trans = btrfs_start_transaction(root, 1);
2478
2479         btrfs_set_trans_block_group(trans, dir);
2480
2481         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
2482
2483         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
2484                                  dentry->d_name.name, dentry->d_name.len);
2485
2486         if (inode->i_nlink == 0)
2487                 ret = btrfs_orphan_add(trans, inode);
2488
2489         nr = trans->blocks_used;
2490
2491         btrfs_end_transaction_throttle(trans, root);
2492         btrfs_btree_balance_dirty(root, nr);
2493         return ret;
2494 }
2495
2496 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
2497                         struct btrfs_root *root,
2498                         struct inode *dir, u64 objectid,
2499                         const char *name, int name_len)
2500 {
2501         struct btrfs_path *path;
2502         struct extent_buffer *leaf;
2503         struct btrfs_dir_item *di;
2504         struct btrfs_key key;
2505         u64 index;
2506         int ret;
2507
2508         path = btrfs_alloc_path();
2509         if (!path)
2510                 return -ENOMEM;
2511
2512         di = btrfs_lookup_dir_item(trans, root, path, dir->i_ino,
2513                                    name, name_len, -1);
2514         BUG_ON(!di || IS_ERR(di));
2515
2516         leaf = path->nodes[0];
2517         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2518         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
2519         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2520         BUG_ON(ret);
2521         btrfs_release_path(root, path);
2522
2523         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
2524                                  objectid, root->root_key.objectid,
2525                                  dir->i_ino, &index, name, name_len);
2526         if (ret < 0) {
2527                 BUG_ON(ret != -ENOENT);
2528                 di = btrfs_search_dir_index_item(root, path, dir->i_ino,
2529                                                  name, name_len);
2530                 BUG_ON(!di || IS_ERR(di));
2531
2532                 leaf = path->nodes[0];
2533                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2534                 btrfs_release_path(root, path);
2535                 index = key.offset;
2536         }
2537
2538         di = btrfs_lookup_dir_index_item(trans, root, path, dir->i_ino,
2539                                          index, name, name_len, -1);
2540         BUG_ON(!di || IS_ERR(di));
2541
2542         leaf = path->nodes[0];
2543         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2544         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
2545         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2546         BUG_ON(ret);
2547         btrfs_release_path(root, path);
2548
2549         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2550         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2551         ret = btrfs_update_inode(trans, root, dir);
2552         BUG_ON(ret);
2553         dir->i_sb->s_dirt = 1;
2554
2555         btrfs_free_path(path);
2556         return 0;
2557 }
2558
2559 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
2560 {
2561         struct inode *inode = dentry->d_inode;
2562         int err = 0;
2563         int ret;
2564         struct btrfs_root *root = BTRFS_I(dir)->root;
2565         struct btrfs_trans_handle *trans;
2566         unsigned long nr = 0;
2567
2568         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
2569             inode->i_ino == BTRFS_FIRST_FREE_OBJECTID)
2570                 return -ENOTEMPTY;
2571
2572         trans = btrfs_start_transaction(root, 1);
2573         btrfs_set_trans_block_group(trans, dir);
2574
2575         if (unlikely(inode->i_ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
2576                 err = btrfs_unlink_subvol(trans, root, dir,
2577                                           BTRFS_I(inode)->location.objectid,
2578                                           dentry->d_name.name,
2579                                           dentry->d_name.len);
2580                 goto out;
2581         }
2582
2583         err = btrfs_orphan_add(trans, inode);
2584         if (err)
2585                 goto out;
2586
2587         /* now the directory is empty */
2588         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
2589                                  dentry->d_name.name, dentry->d_name.len);
2590         if (!err)
2591                 btrfs_i_size_write(inode, 0);
2592 out:
2593         nr = trans->blocks_used;
2594         ret = btrfs_end_transaction_throttle(trans, root);
2595         btrfs_btree_balance_dirty(root, nr);
2596
2597         if (ret && !err)
2598                 err = ret;
2599         return err;
2600 }
2601
2602 #if 0
2603 /*
2604  * when truncating bytes in a file, it is possible to avoid reading
2605  * the leaves that contain only checksum items.  This can be the
2606  * majority of the IO required to delete a large file, but it must
2607  * be done carefully.
2608  *
2609  * The keys in the level just above the leaves are checked to make sure
2610  * the lowest key in a given leaf is a csum key, and starts at an offset
2611  * after the new  size.
2612  *
2613  * Then the key for the next leaf is checked to make sure it also has
2614  * a checksum item for the same file.  If it does, we know our target leaf
2615  * contains only checksum items, and it can be safely freed without reading
2616  * it.
2617  *
2618  * This is just an optimization targeted at large files.  It may do
2619  * nothing.  It will return 0 unless things went badly.
2620  */
2621 static noinline int drop_csum_leaves(struct btrfs_trans_handle *trans,
2622                                      struct btrfs_root *root,
2623                                      struct btrfs_path *path,
2624                                      struct inode *inode, u64 new_size)
2625 {
2626         struct btrfs_key key;
2627         int ret;
2628         int nritems;
2629         struct btrfs_key found_key;
2630         struct btrfs_key other_key;
2631         struct btrfs_leaf_ref *ref;
2632         u64 leaf_gen;
2633         u64 leaf_start;
2634
2635         path->lowest_level = 1;
2636         key.objectid = inode->i_ino;
2637         key.type = BTRFS_CSUM_ITEM_KEY;
2638         key.offset = new_size;
2639 again:
2640         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2641         if (ret < 0)
2642                 goto out;
2643
2644         if (path->nodes[1] == NULL) {
2645                 ret = 0;
2646                 goto out;
2647         }
2648         ret = 0;
2649         btrfs_node_key_to_cpu(path->nodes[1], &found_key, path->slots[1]);
2650         nritems = btrfs_header_nritems(path->nodes[1]);
2651
2652         if (!nritems)
2653                 goto out;
2654
2655         if (path->slots[1] >= nritems)
2656                 goto next_node;
2657
2658         /* did we find a key greater than anything we want to delete? */
2659         if (found_key.objectid > inode->i_ino ||
2660            (found_key.objectid == inode->i_ino && found_key.type > key.type))
2661                 goto out;
2662
2663         /* we check the next key in the node to make sure the leave contains
2664          * only checksum items.  This comparison doesn't work if our
2665          * leaf is the last one in the node
2666          */
2667         if (path->slots[1] + 1 >= nritems) {
2668 next_node:
2669                 /* search forward from the last key in the node, this
2670                  * will bring us into the next node in the tree
2671                  */
2672                 btrfs_node_key_to_cpu(path->nodes[1], &found_key, nritems - 1);
2673
2674                 /* unlikely, but we inc below, so check to be safe */
2675                 if (found_key.offset == (u64)-1)
2676                         goto out;
2677
2678                 /* search_forward needs a path with locks held, do the
2679                  * search again for the original key.  It is possible
2680                  * this will race with a balance and return a path that
2681                  * we could modify, but this drop is just an optimization
2682                  * and is allowed to miss some leaves.
2683                  */
2684                 btrfs_release_path(root, path);
2685                 found_key.offset++;
2686
2687                 /* setup a max key for search_forward */
2688                 other_key.offset = (u64)-1;
2689                 other_key.type = key.type;
2690                 other_key.objectid = key.objectid;
2691
2692                 path->keep_locks = 1;
2693                 ret = btrfs_search_forward(root, &found_key, &other_key,
2694                                            path, 0, 0);
2695                 path->keep_locks = 0;
2696                 if (ret || found_key.objectid != key.objectid ||
2697                     found_key.type != key.type) {
2698                         ret = 0;
2699                         goto out;
2700                 }
2701
2702                 key.offset = found_key.offset;
2703                 btrfs_release_path(root, path);
2704                 cond_resched();
2705                 goto again;
2706         }
2707
2708         /* we know there's one more slot after us in the tree,
2709          * read that key so we can verify it is also a checksum item
2710          */
2711         btrfs_node_key_to_cpu(path->nodes[1], &other_key, path->slots[1] + 1);
2712
2713         if (found_key.objectid < inode->i_ino)
2714                 goto next_key;
2715
2716         if (found_key.type != key.type || found_key.offset < new_size)
2717                 goto next_key;
2718
2719         /*
2720          * if the key for the next leaf isn't a csum key from this objectid,
2721          * we can't be sure there aren't good items inside this leaf.
2722          * Bail out
2723          */
2724         if (other_key.objectid != inode->i_ino || other_key.type != key.type)
2725                 goto out;
2726
2727         leaf_start = btrfs_node_blockptr(path->nodes[1], path->slots[1]);
2728         leaf_gen = btrfs_node_ptr_generation(path->nodes[1], path->slots[1]);
2729         /*
2730          * it is safe to delete this leaf, it contains only
2731          * csum items from this inode at an offset >= new_size
2732          */
2733         ret = btrfs_del_leaf(trans, root, path, leaf_start);
2734         BUG_ON(ret);
2735
2736         if (root->ref_cows && leaf_gen < trans->transid) {
2737                 ref = btrfs_alloc_leaf_ref(root, 0);
2738                 if (ref) {
2739                         ref->root_gen = root->root_key.offset;
2740                         ref->bytenr = leaf_start;
2741                         ref->owner = 0;
2742                         ref->generation = leaf_gen;
2743                         ref->nritems = 0;
2744
2745                         btrfs_sort_leaf_ref(ref);
2746
2747                         ret = btrfs_add_leaf_ref(root, ref, 0);
2748                         WARN_ON(ret);
2749                         btrfs_free_leaf_ref(root, ref);
2750                 } else {
2751                         WARN_ON(1);
2752                 }
2753         }
2754 next_key:
2755         btrfs_release_path(root, path);
2756
2757         if (other_key.objectid == inode->i_ino &&
2758             other_key.type == key.type && other_key.offset > key.offset) {
2759                 key.offset = other_key.offset;
2760                 cond_resched();
2761                 goto again;
2762         }
2763         ret = 0;
2764 out:
2765         /* fixup any changes we've made to the path */
2766         path->lowest_level = 0;
2767         path->keep_locks = 0;
2768         btrfs_release_path(root, path);
2769         return ret;
2770 }
2771
2772 #endif
2773
2774 /*
2775  * this can truncate away extent items, csum items and directory items.
2776  * It starts at a high offset and removes keys until it can't find
2777  * any higher than new_size
2778  *
2779  * csum items that cross the new i_size are truncated to the new size
2780  * as well.
2781  *
2782  * min_type is the minimum key type to truncate down to.  If set to 0, this
2783  * will kill all the items on this inode, including the INODE_ITEM_KEY.
2784  */
2785 noinline int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
2786                                         struct btrfs_root *root,
2787                                         struct inode *inode,
2788                                         u64 new_size, u32 min_type)
2789 {
2790         int ret;
2791         struct btrfs_path *path;
2792         struct btrfs_key key;
2793         struct btrfs_key found_key;
2794         u32 found_type = (u8)-1;
2795         struct extent_buffer *leaf;
2796         struct btrfs_file_extent_item *fi;
2797         u64 extent_start = 0;
2798         u64 extent_num_bytes = 0;
2799         u64 extent_offset = 0;
2800         u64 item_end = 0;
2801         int found_extent;
2802         int del_item;
2803         int pending_del_nr = 0;
2804         int pending_del_slot = 0;
2805         int extent_type = -1;
2806         int encoding;
2807         u64 mask = root->sectorsize - 1;
2808
2809         if (root->ref_cows)
2810                 btrfs_drop_extent_cache(inode, new_size & (~mask), (u64)-1, 0);
2811         path = btrfs_alloc_path();
2812         BUG_ON(!path);
2813         path->reada = -1;
2814
2815         /* FIXME, add redo link to tree so we don't leak on crash */
2816         key.objectid = inode->i_ino;
2817         key.offset = (u64)-1;
2818         key.type = (u8)-1;
2819
2820 search_again:
2821         path->leave_spinning = 1;
2822         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
2823         if (ret < 0)
2824                 goto error;
2825
2826         if (ret > 0) {
2827                 /* there are no items in the tree for us to truncate, we're
2828                  * done
2829                  */
2830                 if (path->slots[0] == 0) {
2831                         ret = 0;
2832                         goto error;
2833                 }
2834                 path->slots[0]--;
2835         }
2836
2837         while (1) {
2838                 fi = NULL;
2839                 leaf = path->nodes[0];
2840                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2841                 found_type = btrfs_key_type(&found_key);
2842                 encoding = 0;
2843
2844                 if (found_key.objectid != inode->i_ino)
2845                         break;
2846
2847                 if (found_type < min_type)
2848                         break;
2849
2850                 item_end = found_key.offset;
2851                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
2852                         fi = btrfs_item_ptr(leaf, path->slots[0],
2853                                             struct btrfs_file_extent_item);
2854                         extent_type = btrfs_file_extent_type(leaf, fi);
2855                         encoding = btrfs_file_extent_compression(leaf, fi);
2856                         encoding |= btrfs_file_extent_encryption(leaf, fi);
2857                         encoding |= btrfs_file_extent_other_encoding(leaf, fi);
2858
2859                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
2860                                 item_end +=
2861                                     btrfs_file_extent_num_bytes(leaf, fi);
2862                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
2863                                 item_end += btrfs_file_extent_inline_len(leaf,
2864                                                                          fi);
2865                         }
2866                         item_end--;
2867                 }
2868                 if (item_end < new_size) {
2869                         if (found_type == BTRFS_DIR_ITEM_KEY)
2870                                 found_type = BTRFS_INODE_ITEM_KEY;
2871                         else if (found_type == BTRFS_EXTENT_ITEM_KEY)
2872                                 found_type = BTRFS_EXTENT_DATA_KEY;
2873                         else if (found_type == BTRFS_EXTENT_DATA_KEY)
2874                                 found_type = BTRFS_XATTR_ITEM_KEY;
2875                         else if (found_type == BTRFS_XATTR_ITEM_KEY)
2876                                 found_type = BTRFS_INODE_REF_KEY;
2877                         else if (found_type)
2878                                 found_type--;
2879                         else
2880                                 break;
2881                         btrfs_set_key_type(&key, found_type);
2882                         goto next;
2883                 }
2884                 if (found_key.offset >= new_size)
2885                         del_item = 1;
2886                 else
2887                         del_item = 0;
2888                 found_extent = 0;
2889
2890                 /* FIXME, shrink the extent if the ref count is only 1 */
2891                 if (found_type != BTRFS_EXTENT_DATA_KEY)
2892                         goto delete;
2893
2894                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
2895                         u64 num_dec;
2896                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
2897                         if (!del_item && !encoding) {
2898                                 u64 orig_num_bytes =
2899                                         btrfs_file_extent_num_bytes(leaf, fi);
2900                                 extent_num_bytes = new_size -
2901                                         found_key.offset + root->sectorsize - 1;
2902                                 extent_num_bytes = extent_num_bytes &
2903                                         ~((u64)root->sectorsize - 1);
2904                                 btrfs_set_file_extent_num_bytes(leaf, fi,
2905                                                          extent_num_bytes);
2906                                 num_dec = (orig_num_bytes -
2907                                            extent_num_bytes);
2908                                 if (root->ref_cows && extent_start != 0)
2909                                         inode_sub_bytes(inode, num_dec);
2910                                 btrfs_mark_buffer_dirty(leaf);
2911                         } else {
2912                                 extent_num_bytes =
2913                                         btrfs_file_extent_disk_num_bytes(leaf,
2914                                                                          fi);
2915                                 extent_offset = found_key.offset -
2916                                         btrfs_file_extent_offset(leaf, fi);
2917
2918                                 /* FIXME blocksize != 4096 */
2919                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
2920                                 if (extent_start != 0) {
2921                                         found_extent = 1;
2922                                         if (root->ref_cows)
2923                                                 inode_sub_bytes(inode, num_dec);
2924                                 }
2925                         }
2926                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
2927                         /*
2928                          * we can't truncate inline items that have had
2929                          * special encodings
2930                          */
2931                         if (!del_item &&
2932                             btrfs_file_extent_compression(leaf, fi) == 0 &&
2933                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
2934                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
2935                                 u32 size = new_size - found_key.offset;
2936
2937                                 if (root->ref_cows) {
2938                                         inode_sub_bytes(inode, item_end + 1 -
2939                                                         new_size);
2940                                 }
2941                                 size =
2942                                     btrfs_file_extent_calc_inline_size(size);
2943                                 ret = btrfs_truncate_item(trans, root, path,
2944                                                           size, 1);
2945                                 BUG_ON(ret);
2946                         } else if (root->ref_cows) {
2947                                 inode_sub_bytes(inode, item_end + 1 -
2948                                                 found_key.offset);
2949                         }
2950                 }
2951 delete:
2952                 if (del_item) {
2953                         if (!pending_del_nr) {
2954                                 /* no pending yet, add ourselves */
2955                                 pending_del_slot = path->slots[0];
2956                                 pending_del_nr = 1;
2957                         } else if (pending_del_nr &&
2958                                    path->slots[0] + 1 == pending_del_slot) {
2959                                 /* hop on the pending chunk */
2960                                 pending_del_nr++;
2961                                 pending_del_slot = path->slots[0];
2962                         } else {
2963                                 BUG();
2964                         }
2965                 } else {
2966                         break;
2967                 }
2968                 if (found_extent && root->ref_cows) {
2969                         btrfs_set_path_blocking(path);
2970                         ret = btrfs_free_extent(trans, root, extent_start,
2971                                                 extent_num_bytes, 0,
2972                                                 btrfs_header_owner(leaf),
2973                                                 inode->i_ino, extent_offset);
2974                         BUG_ON(ret);
2975                 }
2976 next:
2977                 if (path->slots[0] == 0) {
2978                         if (pending_del_nr)
2979                                 goto del_pending;
2980                         btrfs_release_path(root, path);
2981                         if (found_type == BTRFS_INODE_ITEM_KEY)
2982                                 break;
2983                         goto search_again;
2984                 }
2985
2986                 path->slots[0]--;
2987                 if (pending_del_nr &&
2988                     path->slots[0] + 1 != pending_del_slot) {
2989                         struct btrfs_key debug;
2990 del_pending:
2991                         btrfs_item_key_to_cpu(path->nodes[0], &debug,
2992                                               pending_del_slot);
2993                         ret = btrfs_del_items(trans, root, path,
2994                                               pending_del_slot,
2995                                               pending_del_nr);
2996                         BUG_ON(ret);
2997                         pending_del_nr = 0;
2998                         btrfs_release_path(root, path);
2999                         if (found_type == BTRFS_INODE_ITEM_KEY)
3000                                 break;
3001                         goto search_again;
3002                 }
3003         }
3004         ret = 0;
3005 error:
3006         if (pending_del_nr) {
3007                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
3008                                       pending_del_nr);
3009         }
3010         btrfs_free_path(path);
3011         return ret;
3012 }
3013
3014 /*
3015  * taken from block_truncate_page, but does cow as it zeros out
3016  * any bytes left in the last page in the file.
3017  */
3018 static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
3019 {
3020         struct inode *inode = mapping->host;
3021         struct btrfs_root *root = BTRFS_I(inode)->root;
3022         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3023         struct btrfs_ordered_extent *ordered;
3024         char *kaddr;
3025         u32 blocksize = root->sectorsize;
3026         pgoff_t index = from >> PAGE_CACHE_SHIFT;
3027         unsigned offset = from & (PAGE_CACHE_SIZE-1);
3028         struct page *page;
3029         int ret = 0;
3030         u64 page_start;
3031         u64 page_end;
3032
3033         if ((offset & (blocksize - 1)) == 0)
3034                 goto out;
3035         ret = btrfs_check_data_free_space(root, inode, PAGE_CACHE_SIZE);
3036         if (ret)
3037                 goto out;
3038
3039         ret = btrfs_reserve_metadata_for_delalloc(root, inode, 1);
3040         if (ret)
3041                 goto out;
3042
3043         ret = -ENOMEM;
3044 again:
3045         page = grab_cache_page(mapping, index);
3046         if (!page) {
3047                 btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);
3048                 btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
3049                 goto out;
3050         }
3051
3052         page_start = page_offset(page);
3053         page_end = page_start + PAGE_CACHE_SIZE - 1;
3054
3055         if (!PageUptodate(page)) {
3056                 ret = btrfs_readpage(NULL, page);
3057                 lock_page(page);
3058                 if (page->mapping != mapping) {
3059                         unlock_page(page);
3060                         page_cache_release(page);
3061                         goto again;
3062                 }
3063                 if (!PageUptodate(page)) {
3064                         ret = -EIO;
3065                         goto out_unlock;
3066                 }
3067         }
3068         wait_on_page_writeback(page);
3069
3070         lock_extent(io_tree, page_start, page_end, GFP_NOFS);
3071         set_page_extent_mapped(page);
3072
3073         ordered = btrfs_lookup_ordered_extent(inode, page_start);
3074         if (ordered) {
3075                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3076                 unlock_page(page);
3077                 page_cache_release(page);
3078                 btrfs_start_ordered_extent(inode, ordered, 1);
3079                 btrfs_put_ordered_extent(ordered);
3080                 goto again;
3081         }
3082
3083         clear_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end,
3084                           EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING,
3085                           GFP_NOFS);
3086
3087         ret = btrfs_set_extent_delalloc(inode, page_start, page_end);
3088         if (ret) {
3089                 unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3090                 goto out_unlock;
3091         }
3092
3093         ret = 0;
3094         if (offset != PAGE_CACHE_SIZE) {
3095                 kaddr = kmap(page);
3096                 memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
3097                 flush_dcache_page(page);
3098                 kunmap(page);
3099         }
3100         ClearPageChecked(page);
3101         set_page_dirty(page);
3102         unlock_extent(io_tree, page_start, page_end, GFP_NOFS);
3103
3104 out_unlock:
3105         if (ret)
3106                 btrfs_free_reserved_data_space(root, inode, PAGE_CACHE_SIZE);
3107         btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
3108         unlock_page(page);
3109         page_cache_release(page);
3110 out:
3111         return ret;
3112 }
3113
3114 int btrfs_cont_expand(struct inode *inode, loff_t size)
3115 {
3116         struct btrfs_trans_handle *trans;
3117         struct btrfs_root *root = BTRFS_I(inode)->root;
3118         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3119         struct extent_map *em;
3120         u64 mask = root->sectorsize - 1;
3121         u64 hole_start = (inode->i_size + mask) & ~mask;
3122         u64 block_end = (size + mask) & ~mask;
3123         u64 last_byte;
3124         u64 cur_offset;
3125         u64 hole_size;
3126         int err = 0;
3127
3128         if (size <= hole_start)
3129                 return 0;
3130
3131         err = btrfs_truncate_page(inode->i_mapping, inode->i_size);
3132         if (err)
3133                 return err;
3134
3135         while (1) {
3136                 struct btrfs_ordered_extent *ordered;
3137                 btrfs_wait_ordered_range(inode, hole_start,
3138                                          block_end - hole_start);
3139                 lock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
3140                 ordered = btrfs_lookup_ordered_extent(inode, hole_start);
3141                 if (!ordered)
3142                         break;
3143                 unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
3144                 btrfs_put_ordered_extent(ordered);
3145         }
3146
3147         trans = btrfs_start_transaction(root, 1);
3148         btrfs_set_trans_block_group(trans, inode);
3149
3150         cur_offset = hole_start;
3151         while (1) {
3152                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
3153                                 block_end - cur_offset, 0);
3154                 BUG_ON(IS_ERR(em) || !em);
3155                 last_byte = min(extent_map_end(em), block_end);
3156                 last_byte = (last_byte + mask) & ~mask;
3157                 if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
3158                         u64 hint_byte = 0;
3159                         hole_size = last_byte - cur_offset;
3160                         err = btrfs_drop_extents(trans, root, inode,
3161                                                  cur_offset,
3162                                                  cur_offset + hole_size,
3163                                                  block_end,
3164                                                  cur_offset, &hint_byte, 1);
3165                         if (err)
3166                                 break;
3167
3168                         err = btrfs_reserve_metadata_space(root, 1);
3169                         if (err)
3170                                 break;
3171
3172                         err = btrfs_insert_file_extent(trans, root,
3173                                         inode->i_ino, cur_offset, 0,
3174                                         0, hole_size, 0, hole_size,
3175                                         0, 0, 0);
3176                         btrfs_drop_extent_cache(inode, hole_start,
3177                                         last_byte - 1, 0);
3178                         btrfs_unreserve_metadata_space(root, 1);
3179                 }
3180                 free_extent_map(em);
3181                 cur_offset = last_byte;
3182                 if (err || cur_offset >= block_end)
3183                         break;
3184         }
3185
3186         btrfs_end_transaction(trans, root);
3187         unlock_extent(io_tree, hole_start,&nbs