Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs...
[linux-2.6.git] / fs / btrfs / inode.c
1 /*
2  * Copyright (C) 2007 Oracle.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18
19 #include <linux/kernel.h>
20 #include <linux/bio.h>
21 #include <linux/buffer_head.h>
22 #include <linux/file.h>
23 #include <linux/fs.h>
24 #include <linux/pagemap.h>
25 #include <linux/highmem.h>
26 #include <linux/time.h>
27 #include <linux/init.h>
28 #include <linux/string.h>
29 #include <linux/backing-dev.h>
30 #include <linux/mpage.h>
31 #include <linux/swap.h>
32 #include <linux/writeback.h>
33 #include <linux/statfs.h>
34 #include <linux/compat.h>
35 #include <linux/bit_spinlock.h>
36 #include <linux/xattr.h>
37 #include <linux/posix_acl.h>
38 #include <linux/falloc.h>
39 #include <linux/slab.h>
40 #include <linux/ratelimit.h>
41 #include "compat.h"
42 #include "ctree.h"
43 #include "disk-io.h"
44 #include "transaction.h"
45 #include "btrfs_inode.h"
46 #include "ioctl.h"
47 #include "print-tree.h"
48 #include "volumes.h"
49 #include "ordered-data.h"
50 #include "xattr.h"
51 #include "tree-log.h"
52 #include "compression.h"
53 #include "locking.h"
54 #include "free-space-cache.h"
55 #include "inode-map.h"
56
57 struct btrfs_iget_args {
58         u64 ino;
59         struct btrfs_root *root;
60 };
61
62 static const struct inode_operations btrfs_dir_inode_operations;
63 static const struct inode_operations btrfs_symlink_inode_operations;
64 static const struct inode_operations btrfs_dir_ro_inode_operations;
65 static const struct inode_operations btrfs_special_inode_operations;
66 static const struct inode_operations btrfs_file_inode_operations;
67 static const struct address_space_operations btrfs_aops;
68 static const struct address_space_operations btrfs_symlink_aops;
69 static const struct file_operations btrfs_dir_file_operations;
70 static struct extent_io_ops btrfs_extent_io_ops;
71
72 static struct kmem_cache *btrfs_inode_cachep;
73 struct kmem_cache *btrfs_trans_handle_cachep;
74 struct kmem_cache *btrfs_transaction_cachep;
75 struct kmem_cache *btrfs_path_cachep;
76 struct kmem_cache *btrfs_free_space_cachep;
77
78 #define S_SHIFT 12
79 static unsigned char btrfs_type_by_mode[S_IFMT >> S_SHIFT] = {
80         [S_IFREG >> S_SHIFT]    = BTRFS_FT_REG_FILE,
81         [S_IFDIR >> S_SHIFT]    = BTRFS_FT_DIR,
82         [S_IFCHR >> S_SHIFT]    = BTRFS_FT_CHRDEV,
83         [S_IFBLK >> S_SHIFT]    = BTRFS_FT_BLKDEV,
84         [S_IFIFO >> S_SHIFT]    = BTRFS_FT_FIFO,
85         [S_IFSOCK >> S_SHIFT]   = BTRFS_FT_SOCK,
86         [S_IFLNK >> S_SHIFT]    = BTRFS_FT_SYMLINK,
87 };
88
89 static int btrfs_setsize(struct inode *inode, loff_t newsize);
90 static int btrfs_truncate(struct inode *inode);
91 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end);
92 static noinline int cow_file_range(struct inode *inode,
93                                    struct page *locked_page,
94                                    u64 start, u64 end, int *page_started,
95                                    unsigned long *nr_written, int unlock);
96
97 static int btrfs_init_inode_security(struct btrfs_trans_handle *trans,
98                                      struct inode *inode,  struct inode *dir,
99                                      const struct qstr *qstr)
100 {
101         int err;
102
103         err = btrfs_init_acl(trans, inode, dir);
104         if (!err)
105                 err = btrfs_xattr_security_init(trans, inode, dir, qstr);
106         return err;
107 }
108
109 /*
110  * this does all the hard work for inserting an inline extent into
111  * the btree.  The caller should have done a btrfs_drop_extents so that
112  * no overlapping inline items exist in the btree
113  */
114 static noinline int insert_inline_extent(struct btrfs_trans_handle *trans,
115                                 struct btrfs_root *root, struct inode *inode,
116                                 u64 start, size_t size, size_t compressed_size,
117                                 int compress_type,
118                                 struct page **compressed_pages)
119 {
120         struct btrfs_key key;
121         struct btrfs_path *path;
122         struct extent_buffer *leaf;
123         struct page *page = NULL;
124         char *kaddr;
125         unsigned long ptr;
126         struct btrfs_file_extent_item *ei;
127         int err = 0;
128         int ret;
129         size_t cur_size = size;
130         size_t datasize;
131         unsigned long offset;
132
133         if (compressed_size && compressed_pages)
134                 cur_size = compressed_size;
135
136         path = btrfs_alloc_path();
137         if (!path)
138                 return -ENOMEM;
139
140         path->leave_spinning = 1;
141
142         key.objectid = btrfs_ino(inode);
143         key.offset = start;
144         btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
145         datasize = btrfs_file_extent_calc_inline_size(cur_size);
146
147         inode_add_bytes(inode, size);
148         ret = btrfs_insert_empty_item(trans, root, path, &key,
149                                       datasize);
150         BUG_ON(ret);
151         if (ret) {
152                 err = ret;
153                 goto fail;
154         }
155         leaf = path->nodes[0];
156         ei = btrfs_item_ptr(leaf, path->slots[0],
157                             struct btrfs_file_extent_item);
158         btrfs_set_file_extent_generation(leaf, ei, trans->transid);
159         btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
160         btrfs_set_file_extent_encryption(leaf, ei, 0);
161         btrfs_set_file_extent_other_encoding(leaf, ei, 0);
162         btrfs_set_file_extent_ram_bytes(leaf, ei, size);
163         ptr = btrfs_file_extent_inline_start(ei);
164
165         if (compress_type != BTRFS_COMPRESS_NONE) {
166                 struct page *cpage;
167                 int i = 0;
168                 while (compressed_size > 0) {
169                         cpage = compressed_pages[i];
170                         cur_size = min_t(unsigned long, compressed_size,
171                                        PAGE_CACHE_SIZE);
172
173                         kaddr = kmap_atomic(cpage, KM_USER0);
174                         write_extent_buffer(leaf, kaddr, ptr, cur_size);
175                         kunmap_atomic(kaddr, KM_USER0);
176
177                         i++;
178                         ptr += cur_size;
179                         compressed_size -= cur_size;
180                 }
181                 btrfs_set_file_extent_compression(leaf, ei,
182                                                   compress_type);
183         } else {
184                 page = find_get_page(inode->i_mapping,
185                                      start >> PAGE_CACHE_SHIFT);
186                 btrfs_set_file_extent_compression(leaf, ei, 0);
187                 kaddr = kmap_atomic(page, KM_USER0);
188                 offset = start & (PAGE_CACHE_SIZE - 1);
189                 write_extent_buffer(leaf, kaddr + offset, ptr, size);
190                 kunmap_atomic(kaddr, KM_USER0);
191                 page_cache_release(page);
192         }
193         btrfs_mark_buffer_dirty(leaf);
194         btrfs_free_path(path);
195
196         /*
197          * we're an inline extent, so nobody can
198          * extend the file past i_size without locking
199          * a page we already have locked.
200          *
201          * We must do any isize and inode updates
202          * before we unlock the pages.  Otherwise we
203          * could end up racing with unlink.
204          */
205         BTRFS_I(inode)->disk_i_size = inode->i_size;
206         btrfs_update_inode(trans, root, inode);
207
208         return 0;
209 fail:
210         btrfs_free_path(path);
211         return err;
212 }
213
214
215 /*
216  * conditionally insert an inline extent into the file.  This
217  * does the checks required to make sure the data is small enough
218  * to fit as an inline extent.
219  */
220 static noinline int cow_file_range_inline(struct btrfs_trans_handle *trans,
221                                  struct btrfs_root *root,
222                                  struct inode *inode, u64 start, u64 end,
223                                  size_t compressed_size, int compress_type,
224                                  struct page **compressed_pages)
225 {
226         u64 isize = i_size_read(inode);
227         u64 actual_end = min(end + 1, isize);
228         u64 inline_len = actual_end - start;
229         u64 aligned_end = (end + root->sectorsize - 1) &
230                         ~((u64)root->sectorsize - 1);
231         u64 hint_byte;
232         u64 data_len = inline_len;
233         int ret;
234
235         if (compressed_size)
236                 data_len = compressed_size;
237
238         if (start > 0 ||
239             actual_end >= PAGE_CACHE_SIZE ||
240             data_len >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
241             (!compressed_size &&
242             (actual_end & (root->sectorsize - 1)) == 0) ||
243             end + 1 < isize ||
244             data_len > root->fs_info->max_inline) {
245                 return 1;
246         }
247
248         ret = btrfs_drop_extents(trans, inode, start, aligned_end,
249                                  &hint_byte, 1);
250         BUG_ON(ret);
251
252         if (isize > actual_end)
253                 inline_len = min_t(u64, isize, actual_end);
254         ret = insert_inline_extent(trans, root, inode, start,
255                                    inline_len, compressed_size,
256                                    compress_type, compressed_pages);
257         BUG_ON(ret);
258         btrfs_delalloc_release_metadata(inode, end + 1 - start);
259         btrfs_drop_extent_cache(inode, start, aligned_end - 1, 0);
260         return 0;
261 }
262
263 struct async_extent {
264         u64 start;
265         u64 ram_size;
266         u64 compressed_size;
267         struct page **pages;
268         unsigned long nr_pages;
269         int compress_type;
270         struct list_head list;
271 };
272
273 struct async_cow {
274         struct inode *inode;
275         struct btrfs_root *root;
276         struct page *locked_page;
277         u64 start;
278         u64 end;
279         struct list_head extents;
280         struct btrfs_work work;
281 };
282
283 static noinline int add_async_extent(struct async_cow *cow,
284                                      u64 start, u64 ram_size,
285                                      u64 compressed_size,
286                                      struct page **pages,
287                                      unsigned long nr_pages,
288                                      int compress_type)
289 {
290         struct async_extent *async_extent;
291
292         async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
293         BUG_ON(!async_extent);
294         async_extent->start = start;
295         async_extent->ram_size = ram_size;
296         async_extent->compressed_size = compressed_size;
297         async_extent->pages = pages;
298         async_extent->nr_pages = nr_pages;
299         async_extent->compress_type = compress_type;
300         list_add_tail(&async_extent->list, &cow->extents);
301         return 0;
302 }
303
304 /*
305  * we create compressed extents in two phases.  The first
306  * phase compresses a range of pages that have already been
307  * locked (both pages and state bits are locked).
308  *
309  * This is done inside an ordered work queue, and the compression
310  * is spread across many cpus.  The actual IO submission is step
311  * two, and the ordered work queue takes care of making sure that
312  * happens in the same order things were put onto the queue by
313  * writepages and friends.
314  *
315  * If this code finds it can't get good compression, it puts an
316  * entry onto the work queue to write the uncompressed bytes.  This
317  * makes sure that both compressed inodes and uncompressed inodes
318  * are written in the same order that pdflush sent them down.
319  */
320 static noinline int compress_file_range(struct inode *inode,
321                                         struct page *locked_page,
322                                         u64 start, u64 end,
323                                         struct async_cow *async_cow,
324                                         int *num_added)
325 {
326         struct btrfs_root *root = BTRFS_I(inode)->root;
327         struct btrfs_trans_handle *trans;
328         u64 num_bytes;
329         u64 blocksize = root->sectorsize;
330         u64 actual_end;
331         u64 isize = i_size_read(inode);
332         int ret = 0;
333         struct page **pages = NULL;
334         unsigned long nr_pages;
335         unsigned long nr_pages_ret = 0;
336         unsigned long total_compressed = 0;
337         unsigned long total_in = 0;
338         unsigned long max_compressed = 128 * 1024;
339         unsigned long max_uncompressed = 128 * 1024;
340         int i;
341         int will_compress;
342         int compress_type = root->fs_info->compress_type;
343
344         /* if this is a small write inside eof, kick off a defragbot */
345         if (end <= BTRFS_I(inode)->disk_i_size && (end - start + 1) < 16 * 1024)
346                 btrfs_add_inode_defrag(NULL, inode);
347
348         actual_end = min_t(u64, isize, end + 1);
349 again:
350         will_compress = 0;
351         nr_pages = (end >> PAGE_CACHE_SHIFT) - (start >> PAGE_CACHE_SHIFT) + 1;
352         nr_pages = min(nr_pages, (128 * 1024UL) / PAGE_CACHE_SIZE);
353
354         /*
355          * we don't want to send crud past the end of i_size through
356          * compression, that's just a waste of CPU time.  So, if the
357          * end of the file is before the start of our current
358          * requested range of bytes, we bail out to the uncompressed
359          * cleanup code that can deal with all of this.
360          *
361          * It isn't really the fastest way to fix things, but this is a
362          * very uncommon corner.
363          */
364         if (actual_end <= start)
365                 goto cleanup_and_bail_uncompressed;
366
367         total_compressed = actual_end - start;
368
369         /* we want to make sure that amount of ram required to uncompress
370          * an extent is reasonable, so we limit the total size in ram
371          * of a compressed extent to 128k.  This is a crucial number
372          * because it also controls how easily we can spread reads across
373          * cpus for decompression.
374          *
375          * We also want to make sure the amount of IO required to do
376          * a random read is reasonably small, so we limit the size of
377          * a compressed extent to 128k.
378          */
379         total_compressed = min(total_compressed, max_uncompressed);
380         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
381         num_bytes = max(blocksize,  num_bytes);
382         total_in = 0;
383         ret = 0;
384
385         /*
386          * we do compression for mount -o compress and when the
387          * inode has not been flagged as nocompress.  This flag can
388          * change at any time if we discover bad compression ratios.
389          */
390         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) &&
391             (btrfs_test_opt(root, COMPRESS) ||
392              (BTRFS_I(inode)->force_compress) ||
393              (BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))) {
394                 WARN_ON(pages);
395                 pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
396                 BUG_ON(!pages);
397
398                 if (BTRFS_I(inode)->force_compress)
399                         compress_type = BTRFS_I(inode)->force_compress;
400
401                 ret = btrfs_compress_pages(compress_type,
402                                            inode->i_mapping, start,
403                                            total_compressed, pages,
404                                            nr_pages, &nr_pages_ret,
405                                            &total_in,
406                                            &total_compressed,
407                                            max_compressed);
408
409                 if (!ret) {
410                         unsigned long offset = total_compressed &
411                                 (PAGE_CACHE_SIZE - 1);
412                         struct page *page = pages[nr_pages_ret - 1];
413                         char *kaddr;
414
415                         /* zero the tail end of the last page, we might be
416                          * sending it down to disk
417                          */
418                         if (offset) {
419                                 kaddr = kmap_atomic(page, KM_USER0);
420                                 memset(kaddr + offset, 0,
421                                        PAGE_CACHE_SIZE - offset);
422                                 kunmap_atomic(kaddr, KM_USER0);
423                         }
424                         will_compress = 1;
425                 }
426         }
427         if (start == 0) {
428                 trans = btrfs_join_transaction(root);
429                 BUG_ON(IS_ERR(trans));
430                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
431
432                 /* lets try to make an inline extent */
433                 if (ret || total_in < (actual_end - start)) {
434                         /* we didn't compress the entire range, try
435                          * to make an uncompressed inline extent.
436                          */
437                         ret = cow_file_range_inline(trans, root, inode,
438                                                     start, end, 0, 0, NULL);
439                 } else {
440                         /* try making a compressed inline extent */
441                         ret = cow_file_range_inline(trans, root, inode,
442                                                     start, end,
443                                                     total_compressed,
444                                                     compress_type, pages);
445                 }
446                 if (ret == 0) {
447                         /*
448                          * inline extent creation worked, we don't need
449                          * to create any more async work items.  Unlock
450                          * and free up our temp pages.
451                          */
452                         extent_clear_unlock_delalloc(inode,
453                              &BTRFS_I(inode)->io_tree,
454                              start, end, NULL,
455                              EXTENT_CLEAR_UNLOCK_PAGE | EXTENT_CLEAR_DIRTY |
456                              EXTENT_CLEAR_DELALLOC |
457                              EXTENT_SET_WRITEBACK | EXTENT_END_WRITEBACK);
458
459                         btrfs_end_transaction(trans, root);
460                         goto free_pages_out;
461                 }
462                 btrfs_end_transaction(trans, root);
463         }
464
465         if (will_compress) {
466                 /*
467                  * we aren't doing an inline extent round the compressed size
468                  * up to a block size boundary so the allocator does sane
469                  * things
470                  */
471                 total_compressed = (total_compressed + blocksize - 1) &
472                         ~(blocksize - 1);
473
474                 /*
475                  * one last check to make sure the compression is really a
476                  * win, compare the page count read with the blocks on disk
477                  */
478                 total_in = (total_in + PAGE_CACHE_SIZE - 1) &
479                         ~(PAGE_CACHE_SIZE - 1);
480                 if (total_compressed >= total_in) {
481                         will_compress = 0;
482                 } else {
483                         num_bytes = total_in;
484                 }
485         }
486         if (!will_compress && pages) {
487                 /*
488                  * the compression code ran but failed to make things smaller,
489                  * free any pages it allocated and our page pointer array
490                  */
491                 for (i = 0; i < nr_pages_ret; i++) {
492                         WARN_ON(pages[i]->mapping);
493                         page_cache_release(pages[i]);
494                 }
495                 kfree(pages);
496                 pages = NULL;
497                 total_compressed = 0;
498                 nr_pages_ret = 0;
499
500                 /* flag the file so we don't compress in the future */
501                 if (!btrfs_test_opt(root, FORCE_COMPRESS) &&
502                     !(BTRFS_I(inode)->force_compress)) {
503                         BTRFS_I(inode)->flags |= BTRFS_INODE_NOCOMPRESS;
504                 }
505         }
506         if (will_compress) {
507                 *num_added += 1;
508
509                 /* the async work queues will take care of doing actual
510                  * allocation on disk for these compressed pages,
511                  * and will submit them to the elevator.
512                  */
513                 add_async_extent(async_cow, start, num_bytes,
514                                  total_compressed, pages, nr_pages_ret,
515                                  compress_type);
516
517                 if (start + num_bytes < end) {
518                         start += num_bytes;
519                         pages = NULL;
520                         cond_resched();
521                         goto again;
522                 }
523         } else {
524 cleanup_and_bail_uncompressed:
525                 /*
526                  * No compression, but we still need to write the pages in
527                  * the file we've been given so far.  redirty the locked
528                  * page if it corresponds to our extent and set things up
529                  * for the async work queue to run cow_file_range to do
530                  * the normal delalloc dance
531                  */
532                 if (page_offset(locked_page) >= start &&
533                     page_offset(locked_page) <= end) {
534                         __set_page_dirty_nobuffers(locked_page);
535                         /* unlocked later on in the async handlers */
536                 }
537                 add_async_extent(async_cow, start, end - start + 1,
538                                  0, NULL, 0, BTRFS_COMPRESS_NONE);
539                 *num_added += 1;
540         }
541
542 out:
543         return 0;
544
545 free_pages_out:
546         for (i = 0; i < nr_pages_ret; i++) {
547                 WARN_ON(pages[i]->mapping);
548                 page_cache_release(pages[i]);
549         }
550         kfree(pages);
551
552         goto out;
553 }
554
555 /*
556  * phase two of compressed writeback.  This is the ordered portion
557  * of the code, which only gets called in the order the work was
558  * queued.  We walk all the async extents created by compress_file_range
559  * and send them down to the disk.
560  */
561 static noinline int submit_compressed_extents(struct inode *inode,
562                                               struct async_cow *async_cow)
563 {
564         struct async_extent *async_extent;
565         u64 alloc_hint = 0;
566         struct btrfs_trans_handle *trans;
567         struct btrfs_key ins;
568         struct extent_map *em;
569         struct btrfs_root *root = BTRFS_I(inode)->root;
570         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
571         struct extent_io_tree *io_tree;
572         int ret = 0;
573
574         if (list_empty(&async_cow->extents))
575                 return 0;
576
577
578         while (!list_empty(&async_cow->extents)) {
579                 async_extent = list_entry(async_cow->extents.next,
580                                           struct async_extent, list);
581                 list_del(&async_extent->list);
582
583                 io_tree = &BTRFS_I(inode)->io_tree;
584
585 retry:
586                 /* did the compression code fall back to uncompressed IO? */
587                 if (!async_extent->pages) {
588                         int page_started = 0;
589                         unsigned long nr_written = 0;
590
591                         lock_extent(io_tree, async_extent->start,
592                                          async_extent->start +
593                                          async_extent->ram_size - 1, GFP_NOFS);
594
595                         /* allocate blocks */
596                         ret = cow_file_range(inode, async_cow->locked_page,
597                                              async_extent->start,
598                                              async_extent->start +
599                                              async_extent->ram_size - 1,
600                                              &page_started, &nr_written, 0);
601
602                         /*
603                          * if page_started, cow_file_range inserted an
604                          * inline extent and took care of all the unlocking
605                          * and IO for us.  Otherwise, we need to submit
606                          * all those pages down to the drive.
607                          */
608                         if (!page_started && !ret)
609                                 extent_write_locked_range(io_tree,
610                                                   inode, async_extent->start,
611                                                   async_extent->start +
612                                                   async_extent->ram_size - 1,
613                                                   btrfs_get_extent,
614                                                   WB_SYNC_ALL);
615                         kfree(async_extent);
616                         cond_resched();
617                         continue;
618                 }
619
620                 lock_extent(io_tree, async_extent->start,
621                             async_extent->start + async_extent->ram_size - 1,
622                             GFP_NOFS);
623
624                 trans = btrfs_join_transaction(root);
625                 BUG_ON(IS_ERR(trans));
626                 trans->block_rsv = &root->fs_info->delalloc_block_rsv;
627                 ret = btrfs_reserve_extent(trans, root,
628                                            async_extent->compressed_size,
629                                            async_extent->compressed_size,
630                                            0, alloc_hint,
631                                            (u64)-1, &ins, 1);
632                 btrfs_end_transaction(trans, root);
633
634                 if (ret) {
635                         int i;
636                         for (i = 0; i < async_extent->nr_pages; i++) {
637                                 WARN_ON(async_extent->pages[i]->mapping);
638                                 page_cache_release(async_extent->pages[i]);
639                         }
640                         kfree(async_extent->pages);
641                         async_extent->nr_pages = 0;
642                         async_extent->pages = NULL;
643                         unlock_extent(io_tree, async_extent->start,
644                                       async_extent->start +
645                                       async_extent->ram_size - 1, GFP_NOFS);
646                         goto retry;
647                 }
648
649                 /*
650                  * here we're doing allocation and writeback of the
651                  * compressed pages
652                  */
653                 btrfs_drop_extent_cache(inode, async_extent->start,
654                                         async_extent->start +
655                                         async_extent->ram_size - 1, 0);
656
657                 em = alloc_extent_map();
658                 BUG_ON(!em);
659                 em->start = async_extent->start;
660                 em->len = async_extent->ram_size;
661                 em->orig_start = em->start;
662
663                 em->block_start = ins.objectid;
664                 em->block_len = ins.offset;
665                 em->bdev = root->fs_info->fs_devices->latest_bdev;
666                 em->compress_type = async_extent->compress_type;
667                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
668                 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
669
670                 while (1) {
671                         write_lock(&em_tree->lock);
672                         ret = add_extent_mapping(em_tree, em);
673                         write_unlock(&em_tree->lock);
674                         if (ret != -EEXIST) {
675                                 free_extent_map(em);
676                                 break;
677                         }
678                         btrfs_drop_extent_cache(inode, async_extent->start,
679                                                 async_extent->start +
680                                                 async_extent->ram_size - 1, 0);
681                 }
682
683                 ret = btrfs_add_ordered_extent_compress(inode,
684                                                 async_extent->start,
685                                                 ins.objectid,
686                                                 async_extent->ram_size,
687                                                 ins.offset,
688                                                 BTRFS_ORDERED_COMPRESSED,
689                                                 async_extent->compress_type);
690                 BUG_ON(ret);
691
692                 /*
693                  * clear dirty, set writeback and unlock the pages.
694                  */
695                 extent_clear_unlock_delalloc(inode,
696                                 &BTRFS_I(inode)->io_tree,
697                                 async_extent->start,
698                                 async_extent->start +
699                                 async_extent->ram_size - 1,
700                                 NULL, EXTENT_CLEAR_UNLOCK_PAGE |
701                                 EXTENT_CLEAR_UNLOCK |
702                                 EXTENT_CLEAR_DELALLOC |
703                                 EXTENT_CLEAR_DIRTY | EXTENT_SET_WRITEBACK);
704
705                 ret = btrfs_submit_compressed_write(inode,
706                                     async_extent->start,
707                                     async_extent->ram_size,
708                                     ins.objectid,
709                                     ins.offset, async_extent->pages,
710                                     async_extent->nr_pages);
711
712                 BUG_ON(ret);
713                 alloc_hint = ins.objectid + ins.offset;
714                 kfree(async_extent);
715                 cond_resched();
716         }
717
718         return 0;
719 }
720
721 static u64 get_extent_allocation_hint(struct inode *inode, u64 start,
722                                       u64 num_bytes)
723 {
724         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
725         struct extent_map *em;
726         u64 alloc_hint = 0;
727
728         read_lock(&em_tree->lock);
729         em = search_extent_mapping(em_tree, start, num_bytes);
730         if (em) {
731                 /*
732                  * if block start isn't an actual block number then find the
733                  * first block in this inode and use that as a hint.  If that
734                  * block is also bogus then just don't worry about it.
735                  */
736                 if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
737                         free_extent_map(em);
738                         em = search_extent_mapping(em_tree, 0, 0);
739                         if (em && em->block_start < EXTENT_MAP_LAST_BYTE)
740                                 alloc_hint = em->block_start;
741                         if (em)
742                                 free_extent_map(em);
743                 } else {
744                         alloc_hint = em->block_start;
745                         free_extent_map(em);
746                 }
747         }
748         read_unlock(&em_tree->lock);
749
750         return alloc_hint;
751 }
752
753 static inline bool is_free_space_inode(struct btrfs_root *root,
754                                        struct inode *inode)
755 {
756         if (root == root->fs_info->tree_root ||
757             BTRFS_I(inode)->location.objectid == BTRFS_FREE_INO_OBJECTID)
758                 return true;
759         return false;
760 }
761
762 /*
763  * when extent_io.c finds a delayed allocation range in the file,
764  * the call backs end up in this code.  The basic idea is to
765  * allocate extents on disk for the range, and create ordered data structs
766  * in ram to track those extents.
767  *
768  * locked_page is the page that writepage had locked already.  We use
769  * it to make sure we don't do extra locks or unlocks.
770  *
771  * *page_started is set to one if we unlock locked_page and do everything
772  * required to start IO on it.  It may be clean and already done with
773  * IO when we return.
774  */
775 static noinline int cow_file_range(struct inode *inode,
776                                    struct page *locked_page,
777                                    u64 start, u64 end, int *page_started,
778                                    unsigned long *nr_written,
779                                    int unlock)
780 {
781         struct btrfs_root *root = BTRFS_I(inode)->root;
782         struct btrfs_trans_handle *trans;
783         u64 alloc_hint = 0;
784         u64 num_bytes;
785         unsigned long ram_size;
786         u64 disk_num_bytes;
787         u64 cur_alloc_size;
788         u64 blocksize = root->sectorsize;
789         struct btrfs_key ins;
790         struct extent_map *em;
791         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
792         int ret = 0;
793
794         BUG_ON(is_free_space_inode(root, inode));
795         trans = btrfs_join_transaction(root);
796         BUG_ON(IS_ERR(trans));
797         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
798
799         num_bytes = (end - start + blocksize) & ~(blocksize - 1);
800         num_bytes = max(blocksize,  num_bytes);
801         disk_num_bytes = num_bytes;
802         ret = 0;
803
804         /* if this is a small write inside eof, kick off defrag */
805         if (end <= BTRFS_I(inode)->disk_i_size && num_bytes < 64 * 1024)
806                 btrfs_add_inode_defrag(trans, inode);
807
808         if (start == 0) {
809                 /* lets try to make an inline extent */
810                 ret = cow_file_range_inline(trans, root, inode,
811                                             start, end, 0, 0, NULL);
812                 if (ret == 0) {
813                         extent_clear_unlock_delalloc(inode,
814                                      &BTRFS_I(inode)->io_tree,
815                                      start, end, NULL,
816                                      EXTENT_CLEAR_UNLOCK_PAGE |
817                                      EXTENT_CLEAR_UNLOCK |
818                                      EXTENT_CLEAR_DELALLOC |
819                                      EXTENT_CLEAR_DIRTY |
820                                      EXTENT_SET_WRITEBACK |
821                                      EXTENT_END_WRITEBACK);
822
823                         *nr_written = *nr_written +
824                              (end - start + PAGE_CACHE_SIZE) / PAGE_CACHE_SIZE;
825                         *page_started = 1;
826                         ret = 0;
827                         goto out;
828                 }
829         }
830
831         BUG_ON(disk_num_bytes >
832                btrfs_super_total_bytes(&root->fs_info->super_copy));
833
834         alloc_hint = get_extent_allocation_hint(inode, start, num_bytes);
835         btrfs_drop_extent_cache(inode, start, start + num_bytes - 1, 0);
836
837         while (disk_num_bytes > 0) {
838                 unsigned long op;
839
840                 cur_alloc_size = disk_num_bytes;
841                 ret = btrfs_reserve_extent(trans, root, cur_alloc_size,
842                                            root->sectorsize, 0, alloc_hint,
843                                            (u64)-1, &ins, 1);
844                 BUG_ON(ret);
845
846                 em = alloc_extent_map();
847                 BUG_ON(!em);
848                 em->start = start;
849                 em->orig_start = em->start;
850                 ram_size = ins.offset;
851                 em->len = ins.offset;
852
853                 em->block_start = ins.objectid;
854                 em->block_len = ins.offset;
855                 em->bdev = root->fs_info->fs_devices->latest_bdev;
856                 set_bit(EXTENT_FLAG_PINNED, &em->flags);
857
858                 while (1) {
859                         write_lock(&em_tree->lock);
860                         ret = add_extent_mapping(em_tree, em);
861                         write_unlock(&em_tree->lock);
862                         if (ret != -EEXIST) {
863                                 free_extent_map(em);
864                                 break;
865                         }
866                         btrfs_drop_extent_cache(inode, start,
867                                                 start + ram_size - 1, 0);
868                 }
869
870                 cur_alloc_size = ins.offset;
871                 ret = btrfs_add_ordered_extent(inode, start, ins.objectid,
872                                                ram_size, cur_alloc_size, 0);
873                 BUG_ON(ret);
874
875                 if (root->root_key.objectid ==
876                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
877                         ret = btrfs_reloc_clone_csums(inode, start,
878                                                       cur_alloc_size);
879                         BUG_ON(ret);
880                 }
881
882                 if (disk_num_bytes < cur_alloc_size)
883                         break;
884
885                 /* we're not doing compressed IO, don't unlock the first
886                  * page (which the caller expects to stay locked), don't
887                  * clear any dirty bits and don't set any writeback bits
888                  *
889                  * Do set the Private2 bit so we know this page was properly
890                  * setup for writepage
891                  */
892                 op = unlock ? EXTENT_CLEAR_UNLOCK_PAGE : 0;
893                 op |= EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
894                         EXTENT_SET_PRIVATE2;
895
896                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
897                                              start, start + ram_size - 1,
898                                              locked_page, op);
899                 disk_num_bytes -= cur_alloc_size;
900                 num_bytes -= cur_alloc_size;
901                 alloc_hint = ins.objectid + ins.offset;
902                 start += cur_alloc_size;
903         }
904 out:
905         ret = 0;
906         btrfs_end_transaction(trans, root);
907
908         return ret;
909 }
910
911 /*
912  * work queue call back to started compression on a file and pages
913  */
914 static noinline void async_cow_start(struct btrfs_work *work)
915 {
916         struct async_cow *async_cow;
917         int num_added = 0;
918         async_cow = container_of(work, struct async_cow, work);
919
920         compress_file_range(async_cow->inode, async_cow->locked_page,
921                             async_cow->start, async_cow->end, async_cow,
922                             &num_added);
923         if (num_added == 0)
924                 async_cow->inode = NULL;
925 }
926
927 /*
928  * work queue call back to submit previously compressed pages
929  */
930 static noinline void async_cow_submit(struct btrfs_work *work)
931 {
932         struct async_cow *async_cow;
933         struct btrfs_root *root;
934         unsigned long nr_pages;
935
936         async_cow = container_of(work, struct async_cow, work);
937
938         root = async_cow->root;
939         nr_pages = (async_cow->end - async_cow->start + PAGE_CACHE_SIZE) >>
940                 PAGE_CACHE_SHIFT;
941
942         atomic_sub(nr_pages, &root->fs_info->async_delalloc_pages);
943
944         if (atomic_read(&root->fs_info->async_delalloc_pages) <
945             5 * 1042 * 1024 &&
946             waitqueue_active(&root->fs_info->async_submit_wait))
947                 wake_up(&root->fs_info->async_submit_wait);
948
949         if (async_cow->inode)
950                 submit_compressed_extents(async_cow->inode, async_cow);
951 }
952
953 static noinline void async_cow_free(struct btrfs_work *work)
954 {
955         struct async_cow *async_cow;
956         async_cow = container_of(work, struct async_cow, work);
957         kfree(async_cow);
958 }
959
960 static int cow_file_range_async(struct inode *inode, struct page *locked_page,
961                                 u64 start, u64 end, int *page_started,
962                                 unsigned long *nr_written)
963 {
964         struct async_cow *async_cow;
965         struct btrfs_root *root = BTRFS_I(inode)->root;
966         unsigned long nr_pages;
967         u64 cur_end;
968         int limit = 10 * 1024 * 1042;
969
970         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, end, EXTENT_LOCKED,
971                          1, 0, NULL, GFP_NOFS);
972         while (start < end) {
973                 async_cow = kmalloc(sizeof(*async_cow), GFP_NOFS);
974                 BUG_ON(!async_cow);
975                 async_cow->inode = inode;
976                 async_cow->root = root;
977                 async_cow->locked_page = locked_page;
978                 async_cow->start = start;
979
980                 if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS)
981                         cur_end = end;
982                 else
983                         cur_end = min(end, start + 512 * 1024 - 1);
984
985                 async_cow->end = cur_end;
986                 INIT_LIST_HEAD(&async_cow->extents);
987
988                 async_cow->work.func = async_cow_start;
989                 async_cow->work.ordered_func = async_cow_submit;
990                 async_cow->work.ordered_free = async_cow_free;
991                 async_cow->work.flags = 0;
992
993                 nr_pages = (cur_end - start + PAGE_CACHE_SIZE) >>
994                         PAGE_CACHE_SHIFT;
995                 atomic_add(nr_pages, &root->fs_info->async_delalloc_pages);
996
997                 btrfs_queue_worker(&root->fs_info->delalloc_workers,
998                                    &async_cow->work);
999
1000                 if (atomic_read(&root->fs_info->async_delalloc_pages) > limit) {
1001                         wait_event(root->fs_info->async_submit_wait,
1002                            (atomic_read(&root->fs_info->async_delalloc_pages) <
1003                             limit));
1004                 }
1005
1006                 while (atomic_read(&root->fs_info->async_submit_draining) &&
1007                       atomic_read(&root->fs_info->async_delalloc_pages)) {
1008                         wait_event(root->fs_info->async_submit_wait,
1009                           (atomic_read(&root->fs_info->async_delalloc_pages) ==
1010                            0));
1011                 }
1012
1013                 *nr_written += nr_pages;
1014                 start = cur_end + 1;
1015         }
1016         *page_started = 1;
1017         return 0;
1018 }
1019
1020 static noinline int csum_exist_in_range(struct btrfs_root *root,
1021                                         u64 bytenr, u64 num_bytes)
1022 {
1023         int ret;
1024         struct btrfs_ordered_sum *sums;
1025         LIST_HEAD(list);
1026
1027         ret = btrfs_lookup_csums_range(root->fs_info->csum_root, bytenr,
1028                                        bytenr + num_bytes - 1, &list, 0);
1029         if (ret == 0 && list_empty(&list))
1030                 return 0;
1031
1032         while (!list_empty(&list)) {
1033                 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
1034                 list_del(&sums->list);
1035                 kfree(sums);
1036         }
1037         return 1;
1038 }
1039
1040 /*
1041  * when nowcow writeback call back.  This checks for snapshots or COW copies
1042  * of the extents that exist in the file, and COWs the file as required.
1043  *
1044  * If no cow copies or snapshots exist, we write directly to the existing
1045  * blocks on disk
1046  */
1047 static noinline int run_delalloc_nocow(struct inode *inode,
1048                                        struct page *locked_page,
1049                               u64 start, u64 end, int *page_started, int force,
1050                               unsigned long *nr_written)
1051 {
1052         struct btrfs_root *root = BTRFS_I(inode)->root;
1053         struct btrfs_trans_handle *trans;
1054         struct extent_buffer *leaf;
1055         struct btrfs_path *path;
1056         struct btrfs_file_extent_item *fi;
1057         struct btrfs_key found_key;
1058         u64 cow_start;
1059         u64 cur_offset;
1060         u64 extent_end;
1061         u64 extent_offset;
1062         u64 disk_bytenr;
1063         u64 num_bytes;
1064         int extent_type;
1065         int ret;
1066         int type;
1067         int nocow;
1068         int check_prev = 1;
1069         bool nolock;
1070         u64 ino = btrfs_ino(inode);
1071
1072         path = btrfs_alloc_path();
1073         BUG_ON(!path);
1074
1075         nolock = is_free_space_inode(root, inode);
1076
1077         if (nolock)
1078                 trans = btrfs_join_transaction_nolock(root);
1079         else
1080                 trans = btrfs_join_transaction(root);
1081
1082         BUG_ON(IS_ERR(trans));
1083         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1084
1085         cow_start = (u64)-1;
1086         cur_offset = start;
1087         while (1) {
1088                 ret = btrfs_lookup_file_extent(trans, root, path, ino,
1089                                                cur_offset, 0);
1090                 BUG_ON(ret < 0);
1091                 if (ret > 0 && path->slots[0] > 0 && check_prev) {
1092                         leaf = path->nodes[0];
1093                         btrfs_item_key_to_cpu(leaf, &found_key,
1094                                               path->slots[0] - 1);
1095                         if (found_key.objectid == ino &&
1096                             found_key.type == BTRFS_EXTENT_DATA_KEY)
1097                                 path->slots[0]--;
1098                 }
1099                 check_prev = 0;
1100 next_slot:
1101                 leaf = path->nodes[0];
1102                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1103                         ret = btrfs_next_leaf(root, path);
1104                         if (ret < 0)
1105                                 BUG_ON(1);
1106                         if (ret > 0)
1107                                 break;
1108                         leaf = path->nodes[0];
1109                 }
1110
1111                 nocow = 0;
1112                 disk_bytenr = 0;
1113                 num_bytes = 0;
1114                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1115
1116                 if (found_key.objectid > ino ||
1117                     found_key.type > BTRFS_EXTENT_DATA_KEY ||
1118                     found_key.offset > end)
1119                         break;
1120
1121                 if (found_key.offset > cur_offset) {
1122                         extent_end = found_key.offset;
1123                         extent_type = 0;
1124                         goto out_check;
1125                 }
1126
1127                 fi = btrfs_item_ptr(leaf, path->slots[0],
1128                                     struct btrfs_file_extent_item);
1129                 extent_type = btrfs_file_extent_type(leaf, fi);
1130
1131                 if (extent_type == BTRFS_FILE_EXTENT_REG ||
1132                     extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1133                         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1134                         extent_offset = btrfs_file_extent_offset(leaf, fi);
1135                         extent_end = found_key.offset +
1136                                 btrfs_file_extent_num_bytes(leaf, fi);
1137                         if (extent_end <= start) {
1138                                 path->slots[0]++;
1139                                 goto next_slot;
1140                         }
1141                         if (disk_bytenr == 0)
1142                                 goto out_check;
1143                         if (btrfs_file_extent_compression(leaf, fi) ||
1144                             btrfs_file_extent_encryption(leaf, fi) ||
1145                             btrfs_file_extent_other_encoding(leaf, fi))
1146                                 goto out_check;
1147                         if (extent_type == BTRFS_FILE_EXTENT_REG && !force)
1148                                 goto out_check;
1149                         if (btrfs_extent_readonly(root, disk_bytenr))
1150                                 goto out_check;
1151                         if (btrfs_cross_ref_exist(trans, root, ino,
1152                                                   found_key.offset -
1153                                                   extent_offset, disk_bytenr))
1154                                 goto out_check;
1155                         disk_bytenr += extent_offset;
1156                         disk_bytenr += cur_offset - found_key.offset;
1157                         num_bytes = min(end + 1, extent_end) - cur_offset;
1158                         /*
1159                          * force cow if csum exists in the range.
1160                          * this ensure that csum for a given extent are
1161                          * either valid or do not exist.
1162                          */
1163                         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
1164                                 goto out_check;
1165                         nocow = 1;
1166                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
1167                         extent_end = found_key.offset +
1168                                 btrfs_file_extent_inline_len(leaf, fi);
1169                         extent_end = ALIGN(extent_end, root->sectorsize);
1170                 } else {
1171                         BUG_ON(1);
1172                 }
1173 out_check:
1174                 if (extent_end <= start) {
1175                         path->slots[0]++;
1176                         goto next_slot;
1177                 }
1178                 if (!nocow) {
1179                         if (cow_start == (u64)-1)
1180                                 cow_start = cur_offset;
1181                         cur_offset = extent_end;
1182                         if (cur_offset > end)
1183                                 break;
1184                         path->slots[0]++;
1185                         goto next_slot;
1186                 }
1187
1188                 btrfs_release_path(path);
1189                 if (cow_start != (u64)-1) {
1190                         ret = cow_file_range(inode, locked_page, cow_start,
1191                                         found_key.offset - 1, page_started,
1192                                         nr_written, 1);
1193                         BUG_ON(ret);
1194                         cow_start = (u64)-1;
1195                 }
1196
1197                 if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
1198                         struct extent_map *em;
1199                         struct extent_map_tree *em_tree;
1200                         em_tree = &BTRFS_I(inode)->extent_tree;
1201                         em = alloc_extent_map();
1202                         BUG_ON(!em);
1203                         em->start = cur_offset;
1204                         em->orig_start = em->start;
1205                         em->len = num_bytes;
1206                         em->block_len = num_bytes;
1207                         em->block_start = disk_bytenr;
1208                         em->bdev = root->fs_info->fs_devices->latest_bdev;
1209                         set_bit(EXTENT_FLAG_PINNED, &em->flags);
1210                         while (1) {
1211                                 write_lock(&em_tree->lock);
1212                                 ret = add_extent_mapping(em_tree, em);
1213                                 write_unlock(&em_tree->lock);
1214                                 if (ret != -EEXIST) {
1215                                         free_extent_map(em);
1216                                         break;
1217                                 }
1218                                 btrfs_drop_extent_cache(inode, em->start,
1219                                                 em->start + em->len - 1, 0);
1220                         }
1221                         type = BTRFS_ORDERED_PREALLOC;
1222                 } else {
1223                         type = BTRFS_ORDERED_NOCOW;
1224                 }
1225
1226                 ret = btrfs_add_ordered_extent(inode, cur_offset, disk_bytenr,
1227                                                num_bytes, num_bytes, type);
1228                 BUG_ON(ret);
1229
1230                 if (root->root_key.objectid ==
1231                     BTRFS_DATA_RELOC_TREE_OBJECTID) {
1232                         ret = btrfs_reloc_clone_csums(inode, cur_offset,
1233                                                       num_bytes);
1234                         BUG_ON(ret);
1235                 }
1236
1237                 extent_clear_unlock_delalloc(inode, &BTRFS_I(inode)->io_tree,
1238                                 cur_offset, cur_offset + num_bytes - 1,
1239                                 locked_page, EXTENT_CLEAR_UNLOCK_PAGE |
1240                                 EXTENT_CLEAR_UNLOCK | EXTENT_CLEAR_DELALLOC |
1241                                 EXTENT_SET_PRIVATE2);
1242                 cur_offset = extent_end;
1243                 if (cur_offset > end)
1244                         break;
1245         }
1246         btrfs_release_path(path);
1247
1248         if (cur_offset <= end && cow_start == (u64)-1)
1249                 cow_start = cur_offset;
1250         if (cow_start != (u64)-1) {
1251                 ret = cow_file_range(inode, locked_page, cow_start, end,
1252                                      page_started, nr_written, 1);
1253                 BUG_ON(ret);
1254         }
1255
1256         if (nolock) {
1257                 ret = btrfs_end_transaction_nolock(trans, root);
1258                 BUG_ON(ret);
1259         } else {
1260                 ret = btrfs_end_transaction(trans, root);
1261                 BUG_ON(ret);
1262         }
1263         btrfs_free_path(path);
1264         return 0;
1265 }
1266
1267 /*
1268  * extent_io.c call back to do delayed allocation processing
1269  */
1270 static int run_delalloc_range(struct inode *inode, struct page *locked_page,
1271                               u64 start, u64 end, int *page_started,
1272                               unsigned long *nr_written)
1273 {
1274         int ret;
1275         struct btrfs_root *root = BTRFS_I(inode)->root;
1276
1277         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW)
1278                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1279                                          page_started, 1, nr_written);
1280         else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC)
1281                 ret = run_delalloc_nocow(inode, locked_page, start, end,
1282                                          page_started, 0, nr_written);
1283         else if (!btrfs_test_opt(root, COMPRESS) &&
1284                  !(BTRFS_I(inode)->force_compress) &&
1285                  !(BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS))
1286                 ret = cow_file_range(inode, locked_page, start, end,
1287                                       page_started, nr_written, 1);
1288         else
1289                 ret = cow_file_range_async(inode, locked_page, start, end,
1290                                            page_started, nr_written);
1291         return ret;
1292 }
1293
1294 static int btrfs_split_extent_hook(struct inode *inode,
1295                                    struct extent_state *orig, u64 split)
1296 {
1297         /* not delalloc, ignore it */
1298         if (!(orig->state & EXTENT_DELALLOC))
1299                 return 0;
1300
1301         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
1302         return 0;
1303 }
1304
1305 /*
1306  * extent_io.c merge_extent_hook, used to track merged delayed allocation
1307  * extents so we can keep track of new extents that are just merged onto old
1308  * extents, such as when we are doing sequential writes, so we can properly
1309  * account for the metadata space we'll need.
1310  */
1311 static int btrfs_merge_extent_hook(struct inode *inode,
1312                                    struct extent_state *new,
1313                                    struct extent_state *other)
1314 {
1315         /* not delalloc, ignore it */
1316         if (!(other->state & EXTENT_DELALLOC))
1317                 return 0;
1318
1319         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
1320         return 0;
1321 }
1322
1323 /*
1324  * extent_io.c set_bit_hook, used to track delayed allocation
1325  * bytes in this file, and to maintain the list of inodes that
1326  * have pending delalloc work to be done.
1327  */
1328 static int btrfs_set_bit_hook(struct inode *inode,
1329                               struct extent_state *state, int *bits)
1330 {
1331
1332         /*
1333          * set_bit and clear bit hooks normally require _irqsave/restore
1334          * but in this case, we are only testing for the DELALLOC
1335          * bit, which is only set or cleared with irqs on
1336          */
1337         if (!(state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1338                 struct btrfs_root *root = BTRFS_I(inode)->root;
1339                 u64 len = state->end + 1 - state->start;
1340                 bool do_list = !is_free_space_inode(root, inode);
1341
1342                 if (*bits & EXTENT_FIRST_DELALLOC)
1343                         *bits &= ~EXTENT_FIRST_DELALLOC;
1344                 else
1345                         atomic_inc(&BTRFS_I(inode)->outstanding_extents);
1346
1347                 spin_lock(&root->fs_info->delalloc_lock);
1348                 BTRFS_I(inode)->delalloc_bytes += len;
1349                 root->fs_info->delalloc_bytes += len;
1350                 if (do_list && list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1351                         list_add_tail(&BTRFS_I(inode)->delalloc_inodes,
1352                                       &root->fs_info->delalloc_inodes);
1353                 }
1354                 spin_unlock(&root->fs_info->delalloc_lock);
1355         }
1356         return 0;
1357 }
1358
1359 /*
1360  * extent_io.c clear_bit_hook, see set_bit_hook for why
1361  */
1362 static int btrfs_clear_bit_hook(struct inode *inode,
1363                                 struct extent_state *state, int *bits)
1364 {
1365         /*
1366          * set_bit and clear bit hooks normally require _irqsave/restore
1367          * but in this case, we are only testing for the DELALLOC
1368          * bit, which is only set or cleared with irqs on
1369          */
1370         if ((state->state & EXTENT_DELALLOC) && (*bits & EXTENT_DELALLOC)) {
1371                 struct btrfs_root *root = BTRFS_I(inode)->root;
1372                 u64 len = state->end + 1 - state->start;
1373                 bool do_list = !is_free_space_inode(root, inode);
1374
1375                 if (*bits & EXTENT_FIRST_DELALLOC)
1376                         *bits &= ~EXTENT_FIRST_DELALLOC;
1377                 else if (!(*bits & EXTENT_DO_ACCOUNTING))
1378                         atomic_dec(&BTRFS_I(inode)->outstanding_extents);
1379
1380                 if (*bits & EXTENT_DO_ACCOUNTING)
1381                         btrfs_delalloc_release_metadata(inode, len);
1382
1383                 if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID
1384                     && do_list)
1385                         btrfs_free_reserved_data_space(inode, len);
1386
1387                 spin_lock(&root->fs_info->delalloc_lock);
1388                 root->fs_info->delalloc_bytes -= len;
1389                 BTRFS_I(inode)->delalloc_bytes -= len;
1390
1391                 if (do_list && BTRFS_I(inode)->delalloc_bytes == 0 &&
1392                     !list_empty(&BTRFS_I(inode)->delalloc_inodes)) {
1393                         list_del_init(&BTRFS_I(inode)->delalloc_inodes);
1394                 }
1395                 spin_unlock(&root->fs_info->delalloc_lock);
1396         }
1397         return 0;
1398 }
1399
1400 /*
1401  * extent_io.c merge_bio_hook, this must check the chunk tree to make sure
1402  * we don't create bios that span stripes or chunks
1403  */
1404 int btrfs_merge_bio_hook(struct page *page, unsigned long offset,
1405                          size_t size, struct bio *bio,
1406                          unsigned long bio_flags)
1407 {
1408         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
1409         struct btrfs_mapping_tree *map_tree;
1410         u64 logical = (u64)bio->bi_sector << 9;
1411         u64 length = 0;
1412         u64 map_length;
1413         int ret;
1414
1415         if (bio_flags & EXTENT_BIO_COMPRESSED)
1416                 return 0;
1417
1418         length = bio->bi_size;
1419         map_tree = &root->fs_info->mapping_tree;
1420         map_length = length;
1421         ret = btrfs_map_block(map_tree, READ, logical,
1422                               &map_length, NULL, 0);
1423
1424         if (map_length < length + size)
1425                 return 1;
1426         return ret;
1427 }
1428
1429 /*
1430  * in order to insert checksums into the metadata in large chunks,
1431  * we wait until bio submission time.   All the pages in the bio are
1432  * checksummed and sums are attached onto the ordered extent record.
1433  *
1434  * At IO completion time the cums attached on the ordered extent record
1435  * are inserted into the btree
1436  */
1437 static int __btrfs_submit_bio_start(struct inode *inode, int rw,
1438                                     struct bio *bio, int mirror_num,
1439                                     unsigned long bio_flags,
1440                                     u64 bio_offset)
1441 {
1442         struct btrfs_root *root = BTRFS_I(inode)->root;
1443         int ret = 0;
1444
1445         ret = btrfs_csum_one_bio(root, inode, bio, 0, 0);
1446         BUG_ON(ret);
1447         return 0;
1448 }
1449
1450 /*
1451  * in order to insert checksums into the metadata in large chunks,
1452  * we wait until bio submission time.   All the pages in the bio are
1453  * checksummed and sums are attached onto the ordered extent record.
1454  *
1455  * At IO completion time the cums attached on the ordered extent record
1456  * are inserted into the btree
1457  */
1458 static int __btrfs_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
1459                           int mirror_num, unsigned long bio_flags,
1460                           u64 bio_offset)
1461 {
1462         struct btrfs_root *root = BTRFS_I(inode)->root;
1463         return btrfs_map_bio(root, rw, bio, mirror_num, 1);
1464 }
1465
1466 /*
1467  * extent_io.c submission hook. This does the right thing for csum calculation
1468  * on write, or reading the csums from the tree before a read
1469  */
1470 static int btrfs_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
1471                           int mirror_num, unsigned long bio_flags,
1472                           u64 bio_offset)
1473 {
1474         struct btrfs_root *root = BTRFS_I(inode)->root;
1475         int ret = 0;
1476         int skip_sum;
1477
1478         skip_sum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM;
1479
1480         if (is_free_space_inode(root, inode))
1481                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 2);
1482         else
1483                 ret = btrfs_bio_wq_end_io(root->fs_info, bio, 0);
1484         BUG_ON(ret);
1485
1486         if (!(rw & REQ_WRITE)) {
1487                 if (bio_flags & EXTENT_BIO_COMPRESSED) {
1488                         return btrfs_submit_compressed_read(inode, bio,
1489                                                     mirror_num, bio_flags);
1490                 } else if (!skip_sum) {
1491                         ret = btrfs_lookup_bio_sums(root, inode, bio, NULL);
1492                         if (ret)
1493                                 return ret;
1494                 }
1495                 goto mapit;
1496         } else if (!skip_sum) {
1497                 /* csum items have already been cloned */
1498                 if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
1499                         goto mapit;
1500                 /* we're doing a write, do the async checksumming */
1501                 return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
1502                                    inode, rw, bio, mirror_num,
1503                                    bio_flags, bio_offset,
1504                                    __btrfs_submit_bio_start,
1505                                    __btrfs_submit_bio_done);
1506         }
1507
1508 mapit:
1509         return btrfs_map_bio(root, rw, bio, mirror_num, 0);
1510 }
1511
1512 /*
1513  * given a list of ordered sums record them in the inode.  This happens
1514  * at IO completion time based on sums calculated at bio submission time.
1515  */
1516 static noinline int add_pending_csums(struct btrfs_trans_handle *trans,
1517                              struct inode *inode, u64 file_offset,
1518                              struct list_head *list)
1519 {
1520         struct btrfs_ordered_sum *sum;
1521
1522         list_for_each_entry(sum, list, list) {
1523                 btrfs_csum_file_blocks(trans,
1524                        BTRFS_I(inode)->root->fs_info->csum_root, sum);
1525         }
1526         return 0;
1527 }
1528
1529 int btrfs_set_extent_delalloc(struct inode *inode, u64 start, u64 end,
1530                               struct extent_state **cached_state)
1531 {
1532         if ((end & (PAGE_CACHE_SIZE - 1)) == 0)
1533                 WARN_ON(1);
1534         return set_extent_delalloc(&BTRFS_I(inode)->io_tree, start, end,
1535                                    cached_state, GFP_NOFS);
1536 }
1537
1538 /* see btrfs_writepage_start_hook for details on why this is required */
1539 struct btrfs_writepage_fixup {
1540         struct page *page;
1541         struct btrfs_work work;
1542 };
1543
1544 static void btrfs_writepage_fixup_worker(struct btrfs_work *work)
1545 {
1546         struct btrfs_writepage_fixup *fixup;
1547         struct btrfs_ordered_extent *ordered;
1548         struct extent_state *cached_state = NULL;
1549         struct page *page;
1550         struct inode *inode;
1551         u64 page_start;
1552         u64 page_end;
1553
1554         fixup = container_of(work, struct btrfs_writepage_fixup, work);
1555         page = fixup->page;
1556 again:
1557         lock_page(page);
1558         if (!page->mapping || !PageDirty(page) || !PageChecked(page)) {
1559                 ClearPageChecked(page);
1560                 goto out_page;
1561         }
1562
1563         inode = page->mapping->host;
1564         page_start = page_offset(page);
1565         page_end = page_offset(page) + PAGE_CACHE_SIZE - 1;
1566
1567         lock_extent_bits(&BTRFS_I(inode)->io_tree, page_start, page_end, 0,
1568                          &cached_state, GFP_NOFS);
1569
1570         /* already ordered? We're done */
1571         if (PagePrivate2(page))
1572                 goto out;
1573
1574         ordered = btrfs_lookup_ordered_extent(inode, page_start);
1575         if (ordered) {
1576                 unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start,
1577                                      page_end, &cached_state, GFP_NOFS);
1578                 unlock_page(page);
1579                 btrfs_start_ordered_extent(inode, ordered, 1);
1580                 goto again;
1581         }
1582
1583         BUG();
1584         btrfs_set_extent_delalloc(inode, page_start, page_end, &cached_state);
1585         ClearPageChecked(page);
1586 out:
1587         unlock_extent_cached(&BTRFS_I(inode)->io_tree, page_start, page_end,
1588                              &cached_state, GFP_NOFS);
1589 out_page:
1590         unlock_page(page);
1591         page_cache_release(page);
1592         kfree(fixup);
1593 }
1594
1595 /*
1596  * There are a few paths in the higher layers of the kernel that directly
1597  * set the page dirty bit without asking the filesystem if it is a
1598  * good idea.  This causes problems because we want to make sure COW
1599  * properly happens and the data=ordered rules are followed.
1600  *
1601  * In our case any range that doesn't have the ORDERED bit set
1602  * hasn't been properly setup for IO.  We kick off an async process
1603  * to fix it up.  The async helper will wait for ordered extents, set
1604  * the delalloc bit and make it safe to write the page.
1605  */
1606 static int btrfs_writepage_start_hook(struct page *page, u64 start, u64 end)
1607 {
1608         struct inode *inode = page->mapping->host;
1609         struct btrfs_writepage_fixup *fixup;
1610         struct btrfs_root *root = BTRFS_I(inode)->root;
1611
1612         /* this page is properly in the ordered list */
1613         if (TestClearPagePrivate2(page))
1614                 return 0;
1615
1616         if (PageChecked(page))
1617                 return -EAGAIN;
1618
1619         fixup = kzalloc(sizeof(*fixup), GFP_NOFS);
1620         if (!fixup)
1621                 return -EAGAIN;
1622
1623         SetPageChecked(page);
1624         page_cache_get(page);
1625         fixup->work.func = btrfs_writepage_fixup_worker;
1626         fixup->page = page;
1627         btrfs_queue_worker(&root->fs_info->fixup_workers, &fixup->work);
1628         return -EAGAIN;
1629 }
1630
1631 static int insert_reserved_file_extent(struct btrfs_trans_handle *trans,
1632                                        struct inode *inode, u64 file_pos,
1633                                        u64 disk_bytenr, u64 disk_num_bytes,
1634                                        u64 num_bytes, u64 ram_bytes,
1635                                        u8 compression, u8 encryption,
1636                                        u16 other_encoding, int extent_type)
1637 {
1638         struct btrfs_root *root = BTRFS_I(inode)->root;
1639         struct btrfs_file_extent_item *fi;
1640         struct btrfs_path *path;
1641         struct extent_buffer *leaf;
1642         struct btrfs_key ins;
1643         u64 hint;
1644         int ret;
1645
1646         path = btrfs_alloc_path();
1647         BUG_ON(!path);
1648
1649         path->leave_spinning = 1;
1650
1651         /*
1652          * we may be replacing one extent in the tree with another.
1653          * The new extent is pinned in the extent map, and we don't want
1654          * to drop it from the cache until it is completely in the btree.
1655          *
1656          * So, tell btrfs_drop_extents to leave this extent in the cache.
1657          * the caller is expected to unpin it and allow it to be merged
1658          * with the others.
1659          */
1660         ret = btrfs_drop_extents(trans, inode, file_pos, file_pos + num_bytes,
1661                                  &hint, 0);
1662         BUG_ON(ret);
1663
1664         ins.objectid = btrfs_ino(inode);
1665         ins.offset = file_pos;
1666         ins.type = BTRFS_EXTENT_DATA_KEY;
1667         ret = btrfs_insert_empty_item(trans, root, path, &ins, sizeof(*fi));
1668         BUG_ON(ret);
1669         leaf = path->nodes[0];
1670         fi = btrfs_item_ptr(leaf, path->slots[0],
1671                             struct btrfs_file_extent_item);
1672         btrfs_set_file_extent_generation(leaf, fi, trans->transid);
1673         btrfs_set_file_extent_type(leaf, fi, extent_type);
1674         btrfs_set_file_extent_disk_bytenr(leaf, fi, disk_bytenr);
1675         btrfs_set_file_extent_disk_num_bytes(leaf, fi, disk_num_bytes);
1676         btrfs_set_file_extent_offset(leaf, fi, 0);
1677         btrfs_set_file_extent_num_bytes(leaf, fi, num_bytes);
1678         btrfs_set_file_extent_ram_bytes(leaf, fi, ram_bytes);
1679         btrfs_set_file_extent_compression(leaf, fi, compression);
1680         btrfs_set_file_extent_encryption(leaf, fi, encryption);
1681         btrfs_set_file_extent_other_encoding(leaf, fi, other_encoding);
1682
1683         btrfs_unlock_up_safe(path, 1);
1684         btrfs_set_lock_blocking(leaf);
1685
1686         btrfs_mark_buffer_dirty(leaf);
1687
1688         inode_add_bytes(inode, num_bytes);
1689
1690         ins.objectid = disk_bytenr;
1691         ins.offset = disk_num_bytes;
1692         ins.type = BTRFS_EXTENT_ITEM_KEY;
1693         ret = btrfs_alloc_reserved_file_extent(trans, root,
1694                                         root->root_key.objectid,
1695                                         btrfs_ino(inode), file_pos, &ins);
1696         BUG_ON(ret);
1697         btrfs_free_path(path);
1698
1699         return 0;
1700 }
1701
1702 /*
1703  * helper function for btrfs_finish_ordered_io, this
1704  * just reads in some of the csum leaves to prime them into ram
1705  * before we start the transaction.  It limits the amount of btree
1706  * reads required while inside the transaction.
1707  */
1708 /* as ordered data IO finishes, this gets called so we can finish
1709  * an ordered extent if the range of bytes in the file it covers are
1710  * fully written.
1711  */
1712 static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
1713 {
1714         struct btrfs_root *root = BTRFS_I(inode)->root;
1715         struct btrfs_trans_handle *trans = NULL;
1716         struct btrfs_ordered_extent *ordered_extent = NULL;
1717         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1718         struct extent_state *cached_state = NULL;
1719         int compress_type = 0;
1720         int ret;
1721         bool nolock;
1722
1723         ret = btrfs_dec_test_ordered_pending(inode, &ordered_extent, start,
1724                                              end - start + 1);
1725         if (!ret)
1726                 return 0;
1727         BUG_ON(!ordered_extent);
1728
1729         nolock = is_free_space_inode(root, inode);
1730
1731         if (test_bit(BTRFS_ORDERED_NOCOW, &ordered_extent->flags)) {
1732                 BUG_ON(!list_empty(&ordered_extent->list));
1733                 ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1734                 if (!ret) {
1735                         if (nolock)
1736                                 trans = btrfs_join_transaction_nolock(root);
1737                         else
1738                                 trans = btrfs_join_transaction(root);
1739                         BUG_ON(IS_ERR(trans));
1740                         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1741                         ret = btrfs_update_inode(trans, root, inode);
1742                         BUG_ON(ret);
1743                 }
1744                 goto out;
1745         }
1746
1747         lock_extent_bits(io_tree, ordered_extent->file_offset,
1748                          ordered_extent->file_offset + ordered_extent->len - 1,
1749                          0, &cached_state, GFP_NOFS);
1750
1751         if (nolock)
1752                 trans = btrfs_join_transaction_nolock(root);
1753         else
1754                 trans = btrfs_join_transaction(root);
1755         BUG_ON(IS_ERR(trans));
1756         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
1757
1758         if (test_bit(BTRFS_ORDERED_COMPRESSED, &ordered_extent->flags))
1759                 compress_type = ordered_extent->compress_type;
1760         if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
1761                 BUG_ON(compress_type);
1762                 ret = btrfs_mark_extent_written(trans, inode,
1763                                                 ordered_extent->file_offset,
1764                                                 ordered_extent->file_offset +
1765                                                 ordered_extent->len);
1766                 BUG_ON(ret);
1767         } else {
1768                 BUG_ON(root == root->fs_info->tree_root);
1769                 ret = insert_reserved_file_extent(trans, inode,
1770                                                 ordered_extent->file_offset,
1771                                                 ordered_extent->start,
1772                                                 ordered_extent->disk_len,
1773                                                 ordered_extent->len,
1774                                                 ordered_extent->len,
1775                                                 compress_type, 0, 0,
1776                                                 BTRFS_FILE_EXTENT_REG);
1777                 unpin_extent_cache(&BTRFS_I(inode)->extent_tree,
1778                                    ordered_extent->file_offset,
1779                                    ordered_extent->len);
1780                 BUG_ON(ret);
1781         }
1782         unlock_extent_cached(io_tree, ordered_extent->file_offset,
1783                              ordered_extent->file_offset +
1784                              ordered_extent->len - 1, &cached_state, GFP_NOFS);
1785
1786         add_pending_csums(trans, inode, ordered_extent->file_offset,
1787                           &ordered_extent->list);
1788
1789         ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
1790         if (!ret) {
1791                 ret = btrfs_update_inode(trans, root, inode);
1792                 BUG_ON(ret);
1793         }
1794         ret = 0;
1795 out:
1796         if (nolock) {
1797                 if (trans)
1798                         btrfs_end_transaction_nolock(trans, root);
1799         } else {
1800                 btrfs_delalloc_release_metadata(inode, ordered_extent->len);
1801                 if (trans)
1802                         btrfs_end_transaction(trans, root);
1803         }
1804
1805         /* once for us */
1806         btrfs_put_ordered_extent(ordered_extent);
1807         /* once for the tree */
1808         btrfs_put_ordered_extent(ordered_extent);
1809
1810         return 0;
1811 }
1812
1813 static int btrfs_writepage_end_io_hook(struct page *page, u64 start, u64 end,
1814                                 struct extent_state *state, int uptodate)
1815 {
1816         trace_btrfs_writepage_end_io_hook(page, start, end, uptodate);
1817
1818         ClearPagePrivate2(page);
1819         return btrfs_finish_ordered_io(page->mapping->host, start, end);
1820 }
1821
1822 /*
1823  * When IO fails, either with EIO or csum verification fails, we
1824  * try other mirrors that might have a good copy of the data.  This
1825  * io_failure_record is used to record state as we go through all the
1826  * mirrors.  If another mirror has good data, the page is set up to date
1827  * and things continue.  If a good mirror can't be found, the original
1828  * bio end_io callback is called to indicate things have failed.
1829  */
1830 struct io_failure_record {
1831         struct page *page;
1832         u64 start;
1833         u64 len;
1834         u64 logical;
1835         unsigned long bio_flags;
1836         int last_mirror;
1837 };
1838
1839 static int btrfs_io_failed_hook(struct bio *failed_bio,
1840                          struct page *page, u64 start, u64 end,
1841                          struct extent_state *state)
1842 {
1843         struct io_failure_record *failrec = NULL;
1844         u64 private;
1845         struct extent_map *em;
1846         struct inode *inode = page->mapping->host;
1847         struct extent_io_tree *failure_tree = &BTRFS_I(inode)->io_failure_tree;
1848         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
1849         struct bio *bio;
1850         int num_copies;
1851         int ret;
1852         int rw;
1853         u64 logical;
1854
1855         ret = get_state_private(failure_tree, start, &private);
1856         if (ret) {
1857                 failrec = kmalloc(sizeof(*failrec), GFP_NOFS);
1858                 if (!failrec)
1859                         return -ENOMEM;
1860                 failrec->start = start;
1861                 failrec->len = end - start + 1;
1862                 failrec->last_mirror = 0;
1863                 failrec->bio_flags = 0;
1864
1865                 read_lock(&em_tree->lock);
1866                 em = lookup_extent_mapping(em_tree, start, failrec->len);
1867                 if (em->start > start || em->start + em->len < start) {
1868                         free_extent_map(em);
1869                         em = NULL;
1870                 }
1871                 read_unlock(&em_tree->lock);
1872
1873                 if (IS_ERR_OR_NULL(em)) {
1874                         kfree(failrec);
1875                         return -EIO;
1876                 }
1877                 logical = start - em->start;
1878                 logical = em->block_start + logical;
1879                 if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
1880                         logical = em->block_start;
1881                         failrec->bio_flags = EXTENT_BIO_COMPRESSED;
1882                         extent_set_compress_type(&failrec->bio_flags,
1883                                                  em->compress_type);
1884                 }
1885                 failrec->logical = logical;
1886                 free_extent_map(em);
1887                 set_extent_bits(failure_tree, start, end, EXTENT_LOCKED |
1888                                 EXTENT_DIRTY, GFP_NOFS);
1889                 set_state_private(failure_tree, start,
1890                                  (u64)(unsigned long)failrec);
1891         } else {
1892                 failrec = (struct io_failure_record *)(unsigned long)private;
1893         }
1894         num_copies = btrfs_num_copies(
1895                               &BTRFS_I(inode)->root->fs_info->mapping_tree,
1896                               failrec->logical, failrec->len);
1897         failrec->last_mirror++;
1898         if (!state) {
1899                 spin_lock(&BTRFS_I(inode)->io_tree.lock);
1900                 state = find_first_extent_bit_state(&BTRFS_I(inode)->io_tree,
1901                                                     failrec->start,
1902                                                     EXTENT_LOCKED);
1903                 if (state && state->start != failrec->start)
1904                         state = NULL;
1905                 spin_unlock(&BTRFS_I(inode)->io_tree.lock);
1906         }
1907         if (!state || failrec->last_mirror > num_copies) {
1908                 set_state_private(failure_tree, failrec->start, 0);
1909                 clear_extent_bits(failure_tree, failrec->start,
1910                                   failrec->start + failrec->len - 1,
1911                                   EXTENT_LOCKED | EXTENT_DIRTY, GFP_NOFS);
1912                 kfree(failrec);
1913                 return -EIO;
1914         }
1915         bio = bio_alloc(GFP_NOFS, 1);
1916         bio->bi_private = state;
1917         bio->bi_end_io = failed_bio->bi_end_io;
1918         bio->bi_sector = failrec->logical >> 9;
1919         bio->bi_bdev = failed_bio->bi_bdev;
1920         bio->bi_size = 0;
1921
1922         bio_add_page(bio, page, failrec->len, start - page_offset(page));
1923         if (failed_bio->bi_rw & REQ_WRITE)
1924                 rw = WRITE;
1925         else
1926                 rw = READ;
1927
1928         ret = BTRFS_I(inode)->io_tree.ops->submit_bio_hook(inode, rw, bio,
1929                                                       failrec->last_mirror,
1930                                                       failrec->bio_flags, 0);
1931         return ret;
1932 }
1933
1934 /*
1935  * each time an IO finishes, we do a fast check in the IO failure tree
1936  * to see if we need to process or clean up an io_failure_record
1937  */
1938 static int btrfs_clean_io_failures(struct inode *inode, u64 start)
1939 {
1940         u64 private;
1941         u64 private_failure;
1942         struct io_failure_record *failure;
1943         int ret;
1944
1945         private = 0;
1946         if (count_range_bits(&BTRFS_I(inode)->io_failure_tree, &private,
1947                              (u64)-1, 1, EXTENT_DIRTY, 0)) {
1948                 ret = get_state_private(&BTRFS_I(inode)->io_failure_tree,
1949                                         start, &private_failure);
1950                 if (ret == 0) {
1951                         failure = (struct io_failure_record *)(unsigned long)
1952                                    private_failure;
1953                         set_state_private(&BTRFS_I(inode)->io_failure_tree,
1954                                           failure->start, 0);
1955                         clear_extent_bits(&BTRFS_I(inode)->io_failure_tree,
1956                                           failure->start,
1957                                           failure->start + failure->len - 1,
1958                                           EXTENT_DIRTY | EXTENT_LOCKED,
1959                                           GFP_NOFS);
1960                         kfree(failure);
1961                 }
1962         }
1963         return 0;
1964 }
1965
1966 /*
1967  * when reads are done, we need to check csums to verify the data is correct
1968  * if there's a match, we allow the bio to finish.  If not, we go through
1969  * the io_failure_record routines to find good copies
1970  */
1971 static int btrfs_readpage_end_io_hook(struct page *page, u64 start, u64 end,
1972                                struct extent_state *state)
1973 {
1974         size_t offset = start - ((u64)page->index << PAGE_CACHE_SHIFT);
1975         struct inode *inode = page->mapping->host;
1976         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
1977         char *kaddr;
1978         u64 private = ~(u32)0;
1979         int ret;
1980         struct btrfs_root *root = BTRFS_I(inode)->root;
1981         u32 csum = ~(u32)0;
1982
1983         if (PageChecked(page)) {
1984                 ClearPageChecked(page);
1985                 goto good;
1986         }
1987
1988         if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM)
1989                 return 0;
1990
1991         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID &&
1992             test_range_bit(io_tree, start, end, EXTENT_NODATASUM, 1, NULL)) {
1993                 clear_extent_bits(io_tree, start, end, EXTENT_NODATASUM,
1994                                   GFP_NOFS);
1995                 return 0;
1996         }
1997
1998         if (state && state->start == start) {
1999                 private = state->private;
2000                 ret = 0;
2001         } else {
2002                 ret = get_state_private(io_tree, start, &private);
2003         }
2004         kaddr = kmap_atomic(page, KM_USER0);
2005         if (ret)
2006                 goto zeroit;
2007
2008         csum = btrfs_csum_data(root, kaddr + offset, csum,  end - start + 1);
2009         btrfs_csum_final(csum, (char *)&csum);
2010         if (csum != private)
2011                 goto zeroit;
2012
2013         kunmap_atomic(kaddr, KM_USER0);
2014 good:
2015         /* if the io failure tree for this inode is non-empty,
2016          * check to see if we've recovered from a failed IO
2017          */
2018         btrfs_clean_io_failures(inode, start);
2019         return 0;
2020
2021 zeroit:
2022         printk_ratelimited(KERN_INFO "btrfs csum failed ino %llu off %llu csum %u "
2023                        "private %llu\n",
2024                        (unsigned long long)btrfs_ino(page->mapping->host),
2025                        (unsigned long long)start, csum,
2026                        (unsigned long long)private);
2027         memset(kaddr + offset, 1, end - start + 1);
2028         flush_dcache_page(page);
2029         kunmap_atomic(kaddr, KM_USER0);
2030         if (private == 0)
2031                 return 0;
2032         return -EIO;
2033 }
2034
2035 struct delayed_iput {
2036         struct list_head list;
2037         struct inode *inode;
2038 };
2039
2040 void btrfs_add_delayed_iput(struct inode *inode)
2041 {
2042         struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info;
2043         struct delayed_iput *delayed;
2044
2045         if (atomic_add_unless(&inode->i_count, -1, 1))
2046                 return;
2047
2048         delayed = kmalloc(sizeof(*delayed), GFP_NOFS | __GFP_NOFAIL);
2049         delayed->inode = inode;
2050
2051         spin_lock(&fs_info->delayed_iput_lock);
2052         list_add_tail(&delayed->list, &fs_info->delayed_iputs);
2053         spin_unlock(&fs_info->delayed_iput_lock);
2054 }
2055
2056 void btrfs_run_delayed_iputs(struct btrfs_root *root)
2057 {
2058         LIST_HEAD(list);
2059         struct btrfs_fs_info *fs_info = root->fs_info;
2060         struct delayed_iput *delayed;
2061         int empty;
2062
2063         spin_lock(&fs_info->delayed_iput_lock);
2064         empty = list_empty(&fs_info->delayed_iputs);
2065         spin_unlock(&fs_info->delayed_iput_lock);
2066         if (empty)
2067                 return;
2068
2069         down_read(&root->fs_info->cleanup_work_sem);
2070         spin_lock(&fs_info->delayed_iput_lock);
2071         list_splice_init(&fs_info->delayed_iputs, &list);
2072         spin_unlock(&fs_info->delayed_iput_lock);
2073
2074         while (!list_empty(&list)) {
2075                 delayed = list_entry(list.next, struct delayed_iput, list);
2076                 list_del(&delayed->list);
2077                 iput(delayed->inode);
2078                 kfree(delayed);
2079         }
2080         up_read(&root->fs_info->cleanup_work_sem);
2081 }
2082
2083 /*
2084  * calculate extra metadata reservation when snapshotting a subvolume
2085  * contains orphan files.
2086  */
2087 void btrfs_orphan_pre_snapshot(struct btrfs_trans_handle *trans,
2088                                 struct btrfs_pending_snapshot *pending,
2089                                 u64 *bytes_to_reserve)
2090 {
2091         struct btrfs_root *root;
2092         struct btrfs_block_rsv *block_rsv;
2093         u64 num_bytes;
2094         int index;
2095
2096         root = pending->root;
2097         if (!root->orphan_block_rsv || list_empty(&root->orphan_list))
2098                 return;
2099
2100         block_rsv = root->orphan_block_rsv;
2101
2102         /* orphan block reservation for the snapshot */
2103         num_bytes = block_rsv->size;
2104
2105         /*
2106          * after the snapshot is created, COWing tree blocks may use more
2107          * space than it frees. So we should make sure there is enough
2108          * reserved space.
2109          */
2110         index = trans->transid & 0x1;
2111         if (block_rsv->reserved + block_rsv->freed[index] < block_rsv->size) {
2112                 num_bytes += block_rsv->size -
2113                              (block_rsv->reserved + block_rsv->freed[index]);
2114         }
2115
2116         *bytes_to_reserve += num_bytes;
2117 }
2118
2119 void btrfs_orphan_post_snapshot(struct btrfs_trans_handle *trans,
2120                                 struct btrfs_pending_snapshot *pending)
2121 {
2122         struct btrfs_root *root = pending->root;
2123         struct btrfs_root *snap = pending->snap;
2124         struct btrfs_block_rsv *block_rsv;
2125         u64 num_bytes;
2126         int index;
2127         int ret;
2128
2129         if (!root->orphan_block_rsv || list_empty(&root->orphan_list))
2130                 return;
2131
2132         /* refill source subvolume's orphan block reservation */
2133         block_rsv = root->orphan_block_rsv;
2134         index = trans->transid & 0x1;
2135         if (block_rsv->reserved + block_rsv->freed[index] < block_rsv->size) {
2136                 num_bytes = block_rsv->size -
2137                             (block_rsv->reserved + block_rsv->freed[index]);
2138                 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
2139                                               root->orphan_block_rsv,
2140                                               num_bytes);
2141                 BUG_ON(ret);
2142         }
2143
2144         /* setup orphan block reservation for the snapshot */
2145         block_rsv = btrfs_alloc_block_rsv(snap);
2146         BUG_ON(!block_rsv);
2147
2148         btrfs_add_durable_block_rsv(root->fs_info, block_rsv);
2149         snap->orphan_block_rsv = block_rsv;
2150
2151         num_bytes = root->orphan_block_rsv->size;
2152         ret = btrfs_block_rsv_migrate(&pending->block_rsv,
2153                                       block_rsv, num_bytes);
2154         BUG_ON(ret);
2155
2156 #if 0
2157         /* insert orphan item for the snapshot */
2158         WARN_ON(!root->orphan_item_inserted);
2159         ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2160                                        snap->root_key.objectid);
2161         BUG_ON(ret);
2162         snap->orphan_item_inserted = 1;
2163 #endif
2164 }
2165
2166 enum btrfs_orphan_cleanup_state {
2167         ORPHAN_CLEANUP_STARTED  = 1,
2168         ORPHAN_CLEANUP_DONE     = 2,
2169 };
2170
2171 /*
2172  * This is called in transaction commmit time. If there are no orphan
2173  * files in the subvolume, it removes orphan item and frees block_rsv
2174  * structure.
2175  */
2176 void btrfs_orphan_commit_root(struct btrfs_trans_handle *trans,
2177                               struct btrfs_root *root)
2178 {
2179         int ret;
2180
2181         if (!list_empty(&root->orphan_list) ||
2182             root->orphan_cleanup_state != ORPHAN_CLEANUP_DONE)
2183                 return;
2184
2185         if (root->orphan_item_inserted &&
2186             btrfs_root_refs(&root->root_item) > 0) {
2187                 ret = btrfs_del_orphan_item(trans, root->fs_info->tree_root,
2188                                             root->root_key.objectid);
2189                 BUG_ON(ret);
2190                 root->orphan_item_inserted = 0;
2191         }
2192
2193         if (root->orphan_block_rsv) {
2194                 WARN_ON(root->orphan_block_rsv->size > 0);
2195                 btrfs_free_block_rsv(root, root->orphan_block_rsv);
2196                 root->orphan_block_rsv = NULL;
2197         }
2198 }
2199
2200 /*
2201  * This creates an orphan entry for the given inode in case something goes
2202  * wrong in the middle of an unlink/truncate.
2203  *
2204  * NOTE: caller of this function should reserve 5 units of metadata for
2205  *       this function.
2206  */
2207 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode)
2208 {
2209         struct btrfs_root *root = BTRFS_I(inode)->root;
2210         struct btrfs_block_rsv *block_rsv = NULL;
2211         int reserve = 0;
2212         int insert = 0;
2213         int ret;
2214
2215         if (!root->orphan_block_rsv) {
2216                 block_rsv = btrfs_alloc_block_rsv(root);
2217                 BUG_ON(!block_rsv);
2218         }
2219
2220         spin_lock(&root->orphan_lock);
2221         if (!root->orphan_block_rsv) {
2222                 root->orphan_block_rsv = block_rsv;
2223         } else if (block_rsv) {
2224                 btrfs_free_block_rsv(root, block_rsv);
2225                 block_rsv = NULL;
2226         }
2227
2228         if (list_empty(&BTRFS_I(inode)->i_orphan)) {
2229                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2230 #if 0
2231                 /*
2232                  * For proper ENOSPC handling, we should do orphan
2233                  * cleanup when mounting. But this introduces backward
2234                  * compatibility issue.
2235                  */
2236                 if (!xchg(&root->orphan_item_inserted, 1))
2237                         insert = 2;
2238                 else
2239                         insert = 1;
2240 #endif
2241                 insert = 1;
2242         }
2243
2244         if (!BTRFS_I(inode)->orphan_meta_reserved) {
2245                 BTRFS_I(inode)->orphan_meta_reserved = 1;
2246                 reserve = 1;
2247         }
2248         spin_unlock(&root->orphan_lock);
2249
2250         if (block_rsv)
2251                 btrfs_add_durable_block_rsv(root->fs_info, block_rsv);
2252
2253         /* grab metadata reservation from transaction handle */
2254         if (reserve) {
2255                 ret = btrfs_orphan_reserve_metadata(trans, inode);
2256                 BUG_ON(ret);
2257         }
2258
2259         /* insert an orphan item to track this unlinked/truncated file */
2260         if (insert >= 1) {
2261                 ret = btrfs_insert_orphan_item(trans, root, btrfs_ino(inode));
2262                 BUG_ON(ret);
2263         }
2264
2265         /* insert an orphan item to track subvolume contains orphan files */
2266         if (insert >= 2) {
2267                 ret = btrfs_insert_orphan_item(trans, root->fs_info->tree_root,
2268                                                root->root_key.objectid);
2269                 BUG_ON(ret);
2270         }
2271         return 0;
2272 }
2273
2274 /*
2275  * We have done the truncate/delete so we can go ahead and remove the orphan
2276  * item for this particular inode.
2277  */
2278 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode)
2279 {
2280         struct btrfs_root *root = BTRFS_I(inode)->root;
2281         int delete_item = 0;
2282         int release_rsv = 0;
2283         int ret = 0;
2284
2285         spin_lock(&root->orphan_lock);
2286         if (!list_empty(&BTRFS_I(inode)->i_orphan)) {
2287                 list_del_init(&BTRFS_I(inode)->i_orphan);
2288                 delete_item = 1;
2289         }
2290
2291         if (BTRFS_I(inode)->orphan_meta_reserved) {
2292                 BTRFS_I(inode)->orphan_meta_reserved = 0;
2293                 release_rsv = 1;
2294         }
2295         spin_unlock(&root->orphan_lock);
2296
2297         if (trans && delete_item) {
2298                 ret = btrfs_del_orphan_item(trans, root, btrfs_ino(inode));
2299                 BUG_ON(ret);
2300         }
2301
2302         if (release_rsv)
2303                 btrfs_orphan_release_metadata(inode);
2304
2305         return 0;
2306 }
2307
2308 /*
2309  * this cleans up any orphans that may be left on the list from the last use
2310  * of this root.
2311  */
2312 int btrfs_orphan_cleanup(struct btrfs_root *root)
2313 {
2314         struct btrfs_path *path;
2315         struct extent_buffer *leaf;
2316         struct btrfs_key key, found_key;
2317         struct btrfs_trans_handle *trans;
2318         struct inode *inode;
2319         int ret = 0, nr_unlink = 0, nr_truncate = 0;
2320
2321         if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
2322                 return 0;
2323
2324         path = btrfs_alloc_path();
2325         if (!path) {
2326                 ret = -ENOMEM;
2327                 goto out;
2328         }
2329         path->reada = -1;
2330
2331         key.objectid = BTRFS_ORPHAN_OBJECTID;
2332         btrfs_set_key_type(&key, BTRFS_ORPHAN_ITEM_KEY);
2333         key.offset = (u64)-1;
2334
2335         while (1) {
2336                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
2337                 if (ret < 0)
2338                         goto out;
2339
2340                 /*
2341                  * if ret == 0 means we found what we were searching for, which
2342                  * is weird, but possible, so only screw with path if we didn't
2343                  * find the key and see if we have stuff that matches
2344                  */
2345                 if (ret > 0) {
2346                         ret = 0;
2347                         if (path->slots[0] == 0)
2348                                 break;
2349                         path->slots[0]--;
2350                 }
2351
2352                 /* pull out the item */
2353                 leaf = path->nodes[0];
2354                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
2355
2356                 /* make sure the item matches what we want */
2357                 if (found_key.objectid != BTRFS_ORPHAN_OBJECTID)
2358                         break;
2359                 if (btrfs_key_type(&found_key) != BTRFS_ORPHAN_ITEM_KEY)
2360                         break;
2361
2362                 /* release the path since we're done with it */
2363                 btrfs_release_path(path);
2364
2365                 /*
2366                  * this is where we are basically btrfs_lookup, without the
2367                  * crossing root thing.  we store the inode number in the
2368                  * offset of the orphan item.
2369                  */
2370                 found_key.objectid = found_key.offset;
2371                 found_key.type = BTRFS_INODE_ITEM_KEY;
2372                 found_key.offset = 0;
2373                 inode = btrfs_iget(root->fs_info->sb, &found_key, root, NULL);
2374                 if (IS_ERR(inode)) {
2375                         ret = PTR_ERR(inode);
2376                         goto out;
2377                 }
2378
2379                 /*
2380                  * add this inode to the orphan list so btrfs_orphan_del does
2381                  * the proper thing when we hit it
2382                  */
2383                 spin_lock(&root->orphan_lock);
2384                 list_add(&BTRFS_I(inode)->i_orphan, &root->orphan_list);
2385                 spin_unlock(&root->orphan_lock);
2386
2387                 /*
2388                  * if this is a bad inode, means we actually succeeded in
2389                  * removing the inode, but not the orphan record, which means
2390                  * we need to manually delete the orphan since iput will just
2391                  * do a destroy_inode
2392                  */
2393                 if (is_bad_inode(inode)) {
2394                         trans = btrfs_start_transaction(root, 0);
2395                         if (IS_ERR(trans)) {
2396                                 ret = PTR_ERR(trans);
2397                                 goto out;
2398                         }
2399                         btrfs_orphan_del(trans, inode);
2400                         btrfs_end_transaction(trans, root);
2401                         iput(inode);
2402                         continue;
2403                 }
2404
2405                 /* if we have links, this was a truncate, lets do that */
2406                 if (inode->i_nlink) {
2407                         if (!S_ISREG(inode->i_mode)) {
2408                                 WARN_ON(1);
2409                                 iput(inode);
2410                                 continue;
2411                         }
2412                         nr_truncate++;
2413                         ret = btrfs_truncate(inode);
2414                 } else {
2415                         nr_unlink++;
2416                 }
2417
2418                 /* this will do delete_inode and everything for us */
2419                 iput(inode);
2420                 if (ret)
2421                         goto out;
2422         }
2423         root->orphan_cleanup_state = ORPHAN_CLEANUP_DONE;
2424
2425         if (root->orphan_block_rsv)
2426                 btrfs_block_rsv_release(root, root->orphan_block_rsv,
2427                                         (u64)-1);
2428
2429         if (root->orphan_block_rsv || root->orphan_item_inserted) {
2430                 trans = btrfs_join_transaction(root);
2431                 if (!IS_ERR(trans))
2432                         btrfs_end_transaction(trans, root);
2433         }
2434
2435         if (nr_unlink)
2436                 printk(KERN_INFO "btrfs: unlinked %d orphans\n", nr_unlink);
2437         if (nr_truncate)
2438                 printk(KERN_INFO "btrfs: truncated %d orphans\n", nr_truncate);
2439
2440 out:
2441         if (ret)
2442                 printk(KERN_CRIT "btrfs: could not do orphan cleanup %d\n", ret);
2443         btrfs_free_path(path);
2444         return ret;
2445 }
2446
2447 /*
2448  * very simple check to peek ahead in the leaf looking for xattrs.  If we
2449  * don't find any xattrs, we know there can't be any acls.
2450  *
2451  * slot is the slot the inode is in, objectid is the objectid of the inode
2452  */
2453 static noinline int acls_after_inode_item(struct extent_buffer *leaf,
2454                                           int slot, u64 objectid)
2455 {
2456         u32 nritems = btrfs_header_nritems(leaf);
2457         struct btrfs_key found_key;
2458         int scanned = 0;
2459
2460         slot++;
2461         while (slot < nritems) {
2462                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
2463
2464                 /* we found a different objectid, there must not be acls */
2465                 if (found_key.objectid != objectid)
2466                         return 0;
2467
2468                 /* we found an xattr, assume we've got an acl */
2469                 if (found_key.type == BTRFS_XATTR_ITEM_KEY)
2470                         return 1;
2471
2472                 /*
2473                  * we found a key greater than an xattr key, there can't
2474                  * be any acls later on
2475                  */
2476                 if (found_key.type > BTRFS_XATTR_ITEM_KEY)
2477                         return 0;
2478
2479                 slot++;
2480                 scanned++;
2481
2482                 /*
2483                  * it goes inode, inode backrefs, xattrs, extents,
2484                  * so if there are a ton of hard links to an inode there can
2485                  * be a lot of backrefs.  Don't waste time searching too hard,
2486                  * this is just an optimization
2487                  */
2488                 if (scanned >= 8)
2489                         break;
2490         }
2491         /* we hit the end of the leaf before we found an xattr or
2492          * something larger than an xattr.  We have to assume the inode
2493          * has acls
2494          */
2495         return 1;
2496 }
2497
2498 /*
2499  * read an inode from the btree into the in-memory inode
2500  */
2501 static void btrfs_read_locked_inode(struct inode *inode)
2502 {
2503         struct btrfs_path *path;
2504         struct extent_buffer *leaf;
2505         struct btrfs_inode_item *inode_item;
2506         struct btrfs_timespec *tspec;
2507         struct btrfs_root *root = BTRFS_I(inode)->root;
2508         struct btrfs_key location;
2509         int maybe_acls;
2510         u32 rdev;
2511         int ret;
2512
2513         path = btrfs_alloc_path();
2514         BUG_ON(!path);
2515         path->leave_spinning = 1;
2516         memcpy(&location, &BTRFS_I(inode)->location, sizeof(location));
2517
2518         ret = btrfs_lookup_inode(NULL, root, path, &location, 0);
2519         if (ret)
2520                 goto make_bad;
2521
2522         leaf = path->nodes[0];
2523         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2524                                     struct btrfs_inode_item);
2525         if (!leaf->map_token)
2526                 map_private_extent_buffer(leaf, (unsigned long)inode_item,
2527                                           sizeof(struct btrfs_inode_item),
2528                                           &leaf->map_token, &leaf->kaddr,
2529                                           &leaf->map_start, &leaf->map_len,
2530                                           KM_USER1);
2531
2532         inode->i_mode = btrfs_inode_mode(leaf, inode_item);
2533         inode->i_nlink = btrfs_inode_nlink(leaf, inode_item);
2534         inode->i_uid = btrfs_inode_uid(leaf, inode_item);
2535         inode->i_gid = btrfs_inode_gid(leaf, inode_item);
2536         btrfs_i_size_write(inode, btrfs_inode_size(leaf, inode_item));
2537
2538         tspec = btrfs_inode_atime(inode_item);
2539         inode->i_atime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2540         inode->i_atime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2541
2542         tspec = btrfs_inode_mtime(inode_item);
2543         inode->i_mtime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2544         inode->i_mtime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2545
2546         tspec = btrfs_inode_ctime(inode_item);
2547         inode->i_ctime.tv_sec = btrfs_timespec_sec(leaf, tspec);
2548         inode->i_ctime.tv_nsec = btrfs_timespec_nsec(leaf, tspec);
2549
2550         inode_set_bytes(inode, btrfs_inode_nbytes(leaf, inode_item));
2551         BTRFS_I(inode)->generation = btrfs_inode_generation(leaf, inode_item);
2552         BTRFS_I(inode)->sequence = btrfs_inode_sequence(leaf, inode_item);
2553         inode->i_generation = BTRFS_I(inode)->generation;
2554         inode->i_rdev = 0;
2555         rdev = btrfs_inode_rdev(leaf, inode_item);
2556
2557         BTRFS_I(inode)->index_cnt = (u64)-1;
2558         BTRFS_I(inode)->flags = btrfs_inode_flags(leaf, inode_item);
2559
2560         /*
2561          * try to precache a NULL acl entry for files that don't have
2562          * any xattrs or acls
2563          */
2564         maybe_acls = acls_after_inode_item(leaf, path->slots[0],
2565                                            btrfs_ino(inode));
2566         if (!maybe_acls)
2567                 cache_no_acl(inode);
2568
2569         if (leaf->map_token) {
2570                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2571                 leaf->map_token = NULL;
2572         }
2573
2574         btrfs_free_path(path);
2575         inode_item = NULL;
2576
2577         switch (inode->i_mode & S_IFMT) {
2578         case S_IFREG:
2579                 inode->i_mapping->a_ops = &btrfs_aops;
2580                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2581                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
2582                 inode->i_fop = &btrfs_file_operations;
2583                 inode->i_op = &btrfs_file_inode_operations;
2584                 break;
2585         case S_IFDIR:
2586                 inode->i_fop = &btrfs_dir_file_operations;
2587                 if (root == root->fs_info->tree_root)
2588                         inode->i_op = &btrfs_dir_ro_inode_operations;
2589                 else
2590                         inode->i_op = &btrfs_dir_inode_operations;
2591                 break;
2592         case S_IFLNK:
2593                 inode->i_op = &btrfs_symlink_inode_operations;
2594                 inode->i_mapping->a_ops = &btrfs_symlink_aops;
2595                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
2596                 break;
2597         default:
2598                 inode->i_op = &btrfs_special_inode_operations;
2599                 init_special_inode(inode, inode->i_mode, rdev);
2600                 break;
2601         }
2602
2603         btrfs_update_iflags(inode);
2604         return;
2605
2606 make_bad:
2607         btrfs_free_path(path);
2608         make_bad_inode(inode);
2609 }
2610
2611 /*
2612  * given a leaf and an inode, copy the inode fields into the leaf
2613  */
2614 static void fill_inode_item(struct btrfs_trans_handle *trans,
2615                             struct extent_buffer *leaf,
2616                             struct btrfs_inode_item *item,
2617                             struct inode *inode)
2618 {
2619         if (!leaf->map_token)
2620                 map_private_extent_buffer(leaf, (unsigned long)item,
2621                                           sizeof(struct btrfs_inode_item),
2622                                           &leaf->map_token, &leaf->kaddr,
2623                                           &leaf->map_start, &leaf->map_len,
2624                                           KM_USER1);
2625
2626         btrfs_set_inode_uid(leaf, item, inode->i_uid);
2627         btrfs_set_inode_gid(leaf, item, inode->i_gid);
2628         btrfs_set_inode_size(leaf, item, BTRFS_I(inode)->disk_i_size);
2629         btrfs_set_inode_mode(leaf, item, inode->i_mode);
2630         btrfs_set_inode_nlink(leaf, item, inode->i_nlink);
2631
2632         btrfs_set_timespec_sec(leaf, btrfs_inode_atime(item),
2633                                inode->i_atime.tv_sec);
2634         btrfs_set_timespec_nsec(leaf, btrfs_inode_atime(item),
2635                                 inode->i_atime.tv_nsec);
2636
2637         btrfs_set_timespec_sec(leaf, btrfs_inode_mtime(item),
2638                                inode->i_mtime.tv_sec);
2639         btrfs_set_timespec_nsec(leaf, btrfs_inode_mtime(item),
2640                                 inode->i_mtime.tv_nsec);
2641
2642         btrfs_set_timespec_sec(leaf, btrfs_inode_ctime(item),
2643                                inode->i_ctime.tv_sec);
2644         btrfs_set_timespec_nsec(leaf, btrfs_inode_ctime(item),
2645                                 inode->i_ctime.tv_nsec);
2646
2647         btrfs_set_inode_nbytes(leaf, item, inode_get_bytes(inode));
2648         btrfs_set_inode_generation(leaf, item, BTRFS_I(inode)->generation);
2649         btrfs_set_inode_sequence(leaf, item, BTRFS_I(inode)->sequence);
2650         btrfs_set_inode_transid(leaf, item, trans->transid);
2651         btrfs_set_inode_rdev(leaf, item, inode->i_rdev);
2652         btrfs_set_inode_flags(leaf, item, BTRFS_I(inode)->flags);
2653         btrfs_set_inode_block_group(leaf, item, 0);
2654
2655         if (leaf->map_token) {
2656                 unmap_extent_buffer(leaf, leaf->map_token, KM_USER1);
2657                 leaf->map_token = NULL;
2658         }
2659 }
2660
2661 /*
2662  * copy everything in the in-memory inode into the btree.
2663  */
2664 noinline int btrfs_update_inode(struct btrfs_trans_handle *trans,
2665                                 struct btrfs_root *root, struct inode *inode)
2666 {
2667         struct btrfs_inode_item *inode_item;
2668         struct btrfs_path *path;
2669         struct extent_buffer *leaf;
2670         int ret;
2671
2672         /*
2673          * If root is tree root, it means this inode is used to
2674          * store free space information. And these inodes are updated
2675          * when committing the transaction, so they needn't delaye to
2676          * be updated, or deadlock will occured.
2677          */
2678         if (!is_free_space_inode(root, inode)) {
2679                 ret = btrfs_delayed_update_inode(trans, root, inode);
2680                 if (!ret)
2681                         btrfs_set_inode_last_trans(trans, inode);
2682                 return ret;
2683         }
2684
2685         path = btrfs_alloc_path();
2686         if (!path)
2687                 return -ENOMEM;
2688
2689         path->leave_spinning = 1;
2690         ret = btrfs_lookup_inode(trans, root, path, &BTRFS_I(inode)->location,
2691                                  1);
2692         if (ret) {
2693                 if (ret > 0)
2694                         ret = -ENOENT;
2695                 goto failed;
2696         }
2697
2698         btrfs_unlock_up_safe(path, 1);
2699         leaf = path->nodes[0];
2700         inode_item = btrfs_item_ptr(leaf, path->slots[0],
2701                                     struct btrfs_inode_item);
2702
2703         fill_inode_item(trans, leaf, inode_item, inode);
2704         btrfs_mark_buffer_dirty(leaf);
2705         btrfs_set_inode_last_trans(trans, inode);
2706         ret = 0;
2707 failed:
2708         btrfs_free_path(path);
2709         return ret;
2710 }
2711
2712 /*
2713  * unlink helper that gets used here in inode.c and in the tree logging
2714  * recovery code.  It remove a link in a directory with a given name, and
2715  * also drops the back refs in the inode to the directory
2716  */
2717 static int __btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2718                                 struct btrfs_root *root,
2719                                 struct inode *dir, struct inode *inode,
2720                                 const char *name, int name_len)
2721 {
2722         struct btrfs_path *path;
2723         int ret = 0;
2724         struct extent_buffer *leaf;
2725         struct btrfs_dir_item *di;
2726         struct btrfs_key key;
2727         u64 index;
2728         u64 ino = btrfs_ino(inode);
2729         u64 dir_ino = btrfs_ino(dir);
2730
2731         path = btrfs_alloc_path();
2732         if (!path) {
2733                 ret = -ENOMEM;
2734                 goto out;
2735         }
2736
2737         path->leave_spinning = 1;
2738         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2739                                     name, name_len, -1);
2740         if (IS_ERR(di)) {
2741                 ret = PTR_ERR(di);
2742                 goto err;
2743         }
2744         if (!di) {
2745                 ret = -ENOENT;
2746                 goto err;
2747         }
2748         leaf = path->nodes[0];
2749         btrfs_dir_item_key_to_cpu(leaf, di, &key);
2750         ret = btrfs_delete_one_dir_name(trans, root, path, di);
2751         if (ret)
2752                 goto err;
2753         btrfs_release_path(path);
2754
2755         ret = btrfs_del_inode_ref(trans, root, name, name_len, ino,
2756                                   dir_ino, &index);
2757         if (ret) {
2758                 printk(KERN_INFO "btrfs failed to delete reference to %.*s, "
2759                        "inode %llu parent %llu\n", name_len, name,
2760                        (unsigned long long)ino, (unsigned long long)dir_ino);
2761                 goto err;
2762         }
2763
2764         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
2765         if (ret)
2766                 goto err;
2767
2768         ret = btrfs_del_inode_ref_in_log(trans, root, name, name_len,
2769                                          inode, dir_ino);
2770         BUG_ON(ret != 0 && ret != -ENOENT);
2771
2772         ret = btrfs_del_dir_entries_in_log(trans, root, name, name_len,
2773                                            dir, index);
2774         if (ret == -ENOENT)
2775                 ret = 0;
2776 err:
2777         btrfs_free_path(path);
2778         if (ret)
2779                 goto out;
2780
2781         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
2782         inode->i_ctime = dir->i_mtime = dir->i_ctime = CURRENT_TIME;
2783         btrfs_update_inode(trans, root, dir);
2784 out:
2785         return ret;
2786 }
2787
2788 int btrfs_unlink_inode(struct btrfs_trans_handle *trans,
2789                        struct btrfs_root *root,
2790                        struct inode *dir, struct inode *inode,
2791                        const char *name, int name_len)
2792 {
2793         int ret;
2794         ret = __btrfs_unlink_inode(trans, root, dir, inode, name, name_len);
2795         if (!ret) {
2796                 btrfs_drop_nlink(inode);
2797                 ret = btrfs_update_inode(trans, root, inode);
2798         }
2799         return ret;
2800 }
2801                 
2802
2803 /* helper to check if there is any shared block in the path */
2804 static int check_path_shared(struct btrfs_root *root,
2805                              struct btrfs_path *path)
2806 {
2807         struct extent_buffer *eb;
2808         int level;
2809         u64 refs = 1;
2810
2811         for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2812                 int ret;
2813
2814                 if (!path->nodes[level])
2815                         break;
2816                 eb = path->nodes[level];
2817                 if (!btrfs_block_can_be_shared(root, eb))
2818                         continue;
2819                 ret = btrfs_lookup_extent_info(NULL, root, eb->start, eb->len,
2820                                                &refs, NULL);
2821                 if (refs > 1)
2822                         return 1;
2823         }
2824         return 0;
2825 }
2826
2827 /*
2828  * helper to start transaction for unlink and rmdir.
2829  *
2830  * unlink and rmdir are special in btrfs, they do not always free space.
2831  * so in enospc case, we should make sure they will free space before
2832  * allowing them to use the global metadata reservation.
2833  */
2834 static struct btrfs_trans_handle *__unlink_start_trans(struct inode *dir,
2835                                                        struct dentry *dentry)
2836 {
2837         struct btrfs_trans_handle *trans;
2838         struct btrfs_root *root = BTRFS_I(dir)->root;
2839         struct btrfs_path *path;
2840         struct btrfs_inode_ref *ref;
2841         struct btrfs_dir_item *di;
2842         struct inode *inode = dentry->d_inode;
2843         u64 index;
2844         int check_link = 1;
2845         int err = -ENOSPC;
2846         int ret;
2847         u64 ino = btrfs_ino(inode);
2848         u64 dir_ino = btrfs_ino(dir);
2849
2850         trans = btrfs_start_transaction(root, 10);
2851         if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
2852                 return trans;
2853
2854         if (ino == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)
2855                 return ERR_PTR(-ENOSPC);
2856
2857         /* check if there is someone else holds reference */
2858         if (S_ISDIR(inode->i_mode) && atomic_read(&inode->i_count) > 1)
2859                 return ERR_PTR(-ENOSPC);
2860
2861         if (atomic_read(&inode->i_count) > 2)
2862                 return ERR_PTR(-ENOSPC);
2863
2864         if (xchg(&root->fs_info->enospc_unlink, 1))
2865                 return ERR_PTR(-ENOSPC);
2866
2867         path = btrfs_alloc_path();
2868         if (!path) {
2869                 root->fs_info->enospc_unlink = 0;
2870                 return ERR_PTR(-ENOMEM);
2871         }
2872
2873         trans = btrfs_start_transaction(root, 0);
2874         if (IS_ERR(trans)) {
2875                 btrfs_free_path(path);
2876                 root->fs_info->enospc_unlink = 0;
2877                 return trans;
2878         }
2879
2880         path->skip_locking = 1;
2881         path->search_commit_root = 1;
2882
2883         ret = btrfs_lookup_inode(trans, root, path,
2884                                 &BTRFS_I(dir)->location, 0);
2885         if (ret < 0) {
2886                 err = ret;
2887                 goto out;
2888         }
2889         if (ret == 0) {
2890                 if (check_path_shared(root, path))
2891                         goto out;
2892         } else {
2893                 check_link = 0;
2894         }
2895         btrfs_release_path(path);
2896
2897         ret = btrfs_lookup_inode(trans, root, path,
2898                                 &BTRFS_I(inode)->location, 0);
2899         if (ret < 0) {
2900                 err = ret;
2901                 goto out;
2902         }
2903         if (ret == 0) {
2904                 if (check_path_shared(root, path))
2905                         goto out;
2906         } else {
2907                 check_link = 0;
2908         }
2909         btrfs_release_path(path);
2910
2911         if (ret == 0 && S_ISREG(inode->i_mode)) {
2912                 ret = btrfs_lookup_file_extent(trans, root, path,
2913                                                ino, (u64)-1, 0);
2914                 if (ret < 0) {
2915                         err = ret;
2916                         goto out;
2917                 }
2918                 BUG_ON(ret == 0);
2919                 if (check_path_shared(root, path))
2920                         goto out;
2921                 btrfs_release_path(path);
2922         }
2923
2924         if (!check_link) {
2925                 err = 0;
2926                 goto out;
2927         }
2928
2929         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
2930                                 dentry->d_name.name, dentry->d_name.len, 0);
2931         if (IS_ERR(di)) {
2932                 err = PTR_ERR(di);
2933                 goto out;
2934         }
2935         if (di) {
2936                 if (check_path_shared(root, path))
2937                         goto out;
2938         } else {
2939                 err = 0;
2940                 goto out;
2941         }
2942         btrfs_release_path(path);
2943
2944         ref = btrfs_lookup_inode_ref(trans, root, path,
2945                                 dentry->d_name.name, dentry->d_name.len,
2946                                 ino, dir_ino, 0);
2947         if (IS_ERR(ref)) {
2948                 err = PTR_ERR(ref);
2949                 goto out;
2950         }
2951         BUG_ON(!ref);
2952         if (check_path_shared(root, path))
2953                 goto out;
2954         index = btrfs_inode_ref_index(path->nodes[0], ref);
2955         btrfs_release_path(path);
2956
2957         /*
2958          * This is a commit root search, if we can lookup inode item and other
2959          * relative items in the commit root, it means the transaction of
2960          * dir/file creation has been committed, and the dir index item that we
2961          * delay to insert has also been inserted into the commit root. So
2962          * we needn't worry about the delayed insertion of the dir index item
2963          * here.
2964          */
2965         di = btrfs_lookup_dir_index_item(trans, root, path, dir_ino, index,
2966                                 dentry->d_name.name, dentry->d_name.len, 0);
2967         if (IS_ERR(di)) {
2968                 err = PTR_ERR(di);
2969                 goto out;
2970         }
2971         BUG_ON(ret == -ENOENT);
2972         if (check_path_shared(root, path))
2973                 goto out;
2974
2975         err = 0;
2976 out:
2977         btrfs_free_path(path);
2978         if (err) {
2979                 btrfs_end_transaction(trans, root);
2980                 root->fs_info->enospc_unlink = 0;
2981                 return ERR_PTR(err);
2982         }
2983
2984         trans->block_rsv = &root->fs_info->global_block_rsv;
2985         return trans;
2986 }
2987
2988 static void __unlink_end_trans(struct btrfs_trans_handle *trans,
2989                                struct btrfs_root *root)
2990 {
2991         if (trans->block_rsv == &root->fs_info->global_block_rsv) {
2992                 BUG_ON(!root->fs_info->enospc_unlink);
2993                 root->fs_info->enospc_unlink = 0;
2994         }
2995         btrfs_end_transaction_throttle(trans, root);
2996 }
2997
2998 static int btrfs_unlink(struct inode *dir, struct dentry *dentry)
2999 {
3000         struct btrfs_root *root = BTRFS_I(dir)->root;
3001         struct btrfs_trans_handle *trans;
3002         struct inode *inode = dentry->d_inode;
3003         int ret;
3004         unsigned long nr = 0;
3005
3006         trans = __unlink_start_trans(dir, dentry);
3007         if (IS_ERR(trans))
3008                 return PTR_ERR(trans);
3009
3010         btrfs_record_unlink_dir(trans, dir, dentry->d_inode, 0);
3011
3012         ret = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3013                                  dentry->d_name.name, dentry->d_name.len);
3014         BUG_ON(ret);
3015
3016         if (inode->i_nlink == 0) {
3017                 ret = btrfs_orphan_add(trans, inode);
3018                 BUG_ON(ret);
3019         }
3020
3021         nr = trans->blocks_used;
3022         __unlink_end_trans(trans, root);
3023         btrfs_btree_balance_dirty(root, nr);
3024         return ret;
3025 }
3026
3027 int btrfs_unlink_subvol(struct btrfs_trans_handle *trans,
3028                         struct btrfs_root *root,
3029                         struct inode *dir, u64 objectid,
3030                         const char *name, int name_len)
3031 {
3032         struct btrfs_path *path;
3033         struct extent_buffer *leaf;
3034         struct btrfs_dir_item *di;
3035         struct btrfs_key key;
3036         u64 index;
3037         int ret;
3038         u64 dir_ino = btrfs_ino(dir);
3039
3040         path = btrfs_alloc_path();
3041         if (!path)
3042                 return -ENOMEM;
3043
3044         di = btrfs_lookup_dir_item(trans, root, path, dir_ino,
3045                                    name, name_len, -1);
3046         BUG_ON(IS_ERR_OR_NULL(di));
3047
3048         leaf = path->nodes[0];
3049         btrfs_dir_item_key_to_cpu(leaf, di, &key);
3050         WARN_ON(key.type != BTRFS_ROOT_ITEM_KEY || key.objectid != objectid);
3051         ret = btrfs_delete_one_dir_name(trans, root, path, di);
3052         BUG_ON(ret);
3053         btrfs_release_path(path);
3054
3055         ret = btrfs_del_root_ref(trans, root->fs_info->tree_root,
3056                                  objectid, root->root_key.objectid,
3057                                  dir_ino, &index, name, name_len);
3058         if (ret < 0) {
3059                 BUG_ON(ret != -ENOENT);
3060                 di = btrfs_search_dir_index_item(root, path, dir_ino,
3061                                                  name, name_len);
3062                 BUG_ON(IS_ERR_OR_NULL(di));
3063
3064                 leaf = path->nodes[0];
3065                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3066                 btrfs_release_path(path);
3067                 index = key.offset;
3068         }
3069         btrfs_release_path(path);
3070
3071         ret = btrfs_delete_delayed_dir_index(trans, root, dir, index);
3072         BUG_ON(ret);
3073
3074         btrfs_i_size_write(dir, dir->i_size - name_len * 2);
3075         dir->i_mtime = dir->i_ctime = CURRENT_TIME;
3076         ret = btrfs_update_inode(trans, root, dir);
3077         BUG_ON(ret);
3078
3079         return 0;
3080 }
3081
3082 static int btrfs_rmdir(struct inode *dir, struct dentry *dentry)
3083 {
3084         struct inode *inode = dentry->d_inode;
3085         int err = 0;
3086         struct btrfs_root *root = BTRFS_I(dir)->root;
3087         struct btrfs_trans_handle *trans;
3088         unsigned long nr = 0;
3089
3090         if (inode->i_size > BTRFS_EMPTY_DIR_SIZE ||
3091             btrfs_ino(inode) == BTRFS_FIRST_FREE_OBJECTID)
3092                 return -ENOTEMPTY;
3093
3094         trans = __unlink_start_trans(dir, dentry);
3095         if (IS_ERR(trans))
3096                 return PTR_ERR(trans);
3097
3098         if (unlikely(btrfs_ino(inode) == BTRFS_EMPTY_SUBVOL_DIR_OBJECTID)) {
3099                 err = btrfs_unlink_subvol(trans, root, dir,
3100                                           BTRFS_I(inode)->location.objectid,
3101                                           dentry->d_name.name,
3102                                           dentry->d_name.len);
3103                 goto out;
3104         }
3105
3106         err = btrfs_orphan_add(trans, inode);
3107         if (err)
3108                 goto out;
3109
3110         /* now the directory is empty */
3111         err = btrfs_unlink_inode(trans, root, dir, dentry->d_inode,
3112                                  dentry->d_name.name, dentry->d_name.len);
3113         if (!err)
3114                 btrfs_i_size_write(inode, 0);
3115 out:
3116         nr = trans->blocks_used;
3117         __unlink_end_trans(trans, root);
3118         btrfs_btree_balance_dirty(root, nr);
3119
3120         return err;
3121 }
3122
3123 /*
3124  * this can truncate away extent items, csum items and directory items.
3125  * It starts at a high offset and removes keys until it can't find
3126  * any higher than new_size
3127  *
3128  * csum items that cross the new i_size are truncated to the new size
3129  * as well.
3130  *
3131  * min_type is the minimum key type to truncate down to.  If set to 0, this
3132  * will kill all the items on this inode, including the INODE_ITEM_KEY.
3133  */
3134 int btrfs_truncate_inode_items(struct btrfs_trans_handle *trans,
3135                                struct btrfs_root *root,
3136                                struct inode *inode,
3137                                u64 new_size, u32 min_type)
3138 {
3139         struct btrfs_path *path;
3140         struct extent_buffer *leaf;
3141         struct btrfs_file_extent_item *fi;
3142         struct btrfs_key key;
3143         struct btrfs_key found_key;
3144         u64 extent_start = 0;
3145         u64 extent_num_bytes = 0;
3146         u64 extent_offset = 0;
3147         u64 item_end = 0;
3148         u64 mask = root->sectorsize - 1;
3149         u32 found_type = (u8)-1;
3150         int found_extent;
3151         int del_item;
3152         int pending_del_nr = 0;
3153         int pending_del_slot = 0;
3154         int extent_type = -1;
3155         int encoding;
3156         int ret;
3157         int err = 0;
3158         u64 ino = btrfs_ino(inode);
3159
3160         BUG_ON(new_size > 0 && min_type != BTRFS_EXTENT_DATA_KEY);
3161
3162         if (root->ref_cows || root == root->fs_info->tree_root)
3163                 btrfs_drop_extent_cache(inode, new_size & (~mask), (u64)-1, 0);
3164
3165         /*
3166          * This function is also used to drop the items in the log tree before
3167          * we relog the inode, so if root != BTRFS_I(inode)->root, it means
3168          * it is used to drop the loged items. So we shouldn't kill the delayed
3169          * items.
3170          */
3171         if (min_type == 0 && root == BTRFS_I(inode)->root)
3172                 btrfs_kill_delayed_inode_items(inode);
3173
3174         path = btrfs_alloc_path();
3175         BUG_ON(!path);
3176         path->reada = -1;
3177
3178         key.objectid = ino;
3179         key.offset = (u64)-1;
3180         key.type = (u8)-1;
3181
3182 search_again:
3183         path->leave_spinning = 1;
3184         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3185         if (ret < 0) {
3186                 err = ret;
3187                 goto out;
3188         }
3189
3190         if (ret > 0) {
3191                 /* there are no items in the tree for us to truncate, we're
3192                  * done
3193                  */
3194                 if (path->slots[0] == 0)
3195                         goto out;
3196                 path->slots[0]--;
3197         }
3198
3199         while (1) {
3200                 fi = NULL;
3201                 leaf = path->nodes[0];
3202                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
3203                 found_type = btrfs_key_type(&found_key);
3204                 encoding = 0;
3205
3206                 if (found_key.objectid != ino)
3207                         break;
3208
3209                 if (found_type < min_type)
3210                         break;
3211
3212                 item_end = found_key.offset;
3213                 if (found_type == BTRFS_EXTENT_DATA_KEY) {
3214                         fi = btrfs_item_ptr(leaf, path->slots[0],
3215                                             struct btrfs_file_extent_item);
3216                         extent_type = btrfs_file_extent_type(leaf, fi);
3217                         encoding = btrfs_file_extent_compression(leaf, fi);
3218                         encoding |= btrfs_file_extent_encryption(leaf, fi);
3219                         encoding |= btrfs_file_extent_other_encoding(leaf, fi);
3220
3221                         if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3222                                 item_end +=
3223                                     btrfs_file_extent_num_bytes(leaf, fi);
3224                         } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3225                                 item_end += btrfs_file_extent_inline_len(leaf,
3226                                                                          fi);
3227                         }
3228                         item_end--;
3229                 }
3230                 if (found_type > min_type) {
3231                         del_item = 1;
3232                 } else {
3233                         if (item_end < new_size)
3234                                 break;
3235                         if (found_key.offset >= new_size)
3236                                 del_item = 1;
3237                         else
3238                                 del_item = 0;
3239                 }
3240                 found_extent = 0;
3241                 /* FIXME, shrink the extent if the ref count is only 1 */
3242                 if (found_type != BTRFS_EXTENT_DATA_KEY)
3243                         goto delete;
3244
3245                 if (extent_type != BTRFS_FILE_EXTENT_INLINE) {
3246                         u64 num_dec;
3247                         extent_start = btrfs_file_extent_disk_bytenr(leaf, fi);
3248                         if (!del_item && !encoding) {
3249                                 u64 orig_num_bytes =
3250                                         btrfs_file_extent_num_bytes(leaf, fi);
3251                                 extent_num_bytes = new_size -
3252                                         found_key.offset + root->sectorsize - 1;
3253                                 extent_num_bytes = extent_num_bytes &
3254                                         ~((u64)root->sectorsize - 1);
3255                                 btrfs_set_file_extent_num_bytes(leaf, fi,
3256                                                          extent_num_bytes);
3257                                 num_dec = (orig_num_bytes -
3258                                            extent_num_bytes);
3259                                 if (root->ref_cows && extent_start != 0)
3260                                         inode_sub_bytes(inode, num_dec);
3261                                 btrfs_mark_buffer_dirty(leaf);
3262                         } else {
3263                                 extent_num_bytes =
3264                                         btrfs_file_extent_disk_num_bytes(leaf,
3265                                                                          fi);
3266                                 extent_offset = found_key.offset -
3267                                         btrfs_file_extent_offset(leaf, fi);
3268
3269                                 /* FIXME blocksize != 4096 */
3270                                 num_dec = btrfs_file_extent_num_bytes(leaf, fi);
3271                                 if (extent_start != 0) {
3272                                         found_extent = 1;
3273                                         if (root->ref_cows)
3274                                                 inode_sub_bytes(inode, num_dec);
3275                                 }
3276                         }
3277                 } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
3278                         /*
3279                          * we can't truncate inline items that have had
3280                          * special encodings
3281                          */
3282                         if (!del_item &&
3283                             btrfs_file_extent_compression(leaf, fi) == 0 &&
3284                             btrfs_file_extent_encryption(leaf, fi) == 0 &&
3285                             btrfs_file_extent_other_encoding(leaf, fi) == 0) {
3286                                 u32 size = new_size - found_key.offset;
3287
3288                                 if (root->ref_cows) {
3289                                         inode_sub_bytes(inode, item_end + 1 -
3290                                                         new_size);
3291                                 }
3292                                 size =
3293                                     btrfs_file_extent_calc_inline_size(size);
3294                                 ret = btrfs_truncate_item(trans, root, path,
3295                                                           size, 1);
3296                         } else if (root->ref_cows) {
3297                                 inode_sub_bytes(inode, item_end + 1 -
3298                                                 found_key.offset);
3299                         }
3300                 }
3301 delete:
3302                 if (del_item) {
3303                         if (!pending_del_nr) {
3304                                 /* no pending yet, add ourselves */
3305                                 pending_del_slot = path->slots[0];
3306                                 pending_del_nr = 1;
3307                         } else if (pending_del_nr &&
3308                                    path->slots[0] + 1 == pending_del_slot) {
3309                                 /* hop on the pending chunk */
3310                                 pending_del_nr++;
3311                                 pending_del_slot = path->slots[0];
3312                         } else {
3313                                 BUG();
3314                         }
3315                 } else {
3316                         break;
3317                 }
3318                 if (found_extent && (root->ref_cows ||
3319                                      root == root->fs_info->tree_root)) {
3320                         btrfs_set_path_blocking(path);
3321                         ret = btrfs_free_extent(trans, root, extent_start,
3322                                                 extent_num_bytes, 0,
3323                                                 btrfs_header_owner(leaf),
3324                                                 ino, extent_offset);
3325                         BUG_ON(ret);
3326                 }
3327
3328                 if (found_type == BTRFS_INODE_ITEM_KEY)
3329                         break;
3330
3331                 if (path->slots[0] == 0 ||
3332                     path->slots[0] != pending_del_slot) {
3333                         if (root->ref_cows &&
3334                             BTRFS_I(inode)->location.objectid !=
3335                                                 BTRFS_FREE_INO_OBJECTID) {
3336                                 err = -EAGAIN;
3337                                 goto out;
3338                         }
3339                         if (pending_del_nr) {
3340                                 ret = btrfs_del_items(trans, root, path,
3341                                                 pending_del_slot,
3342                                                 pending_del_nr);
3343                                 BUG_ON(ret);
3344                                 pending_del_nr = 0;
3345                         }
3346                         btrfs_release_path(path);
3347                         goto search_again;
3348                 } else {
3349                         path->slots[0]--;
3350                 }
3351         }
3352 out:
3353         if (pending_del_nr) {
3354                 ret = btrfs_del_items(trans, root, path, pending_del_slot,
3355                                       pending_del_nr);
3356                 BUG_ON(ret);
3357         }
3358         btrfs_free_path(path);
3359         return err;
3360 }
3361
3362 /*
3363  * taken from block_truncate_page, but does cow as it zeros out
3364  * any bytes left in the last page in the file.
3365  */
3366 static int btrfs_truncate_page(struct address_space *mapping, loff_t from)
3367 {
3368         struct inode *inode = mapping->host;
3369         struct btrfs_root *root = BTRFS_I(inode)->root;
3370         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3371         struct btrfs_ordered_extent *ordered;
3372         struct extent_state *cached_state = NULL;
3373         char *kaddr;
3374         u32 blocksize = root->sectorsize;
3375         pgoff_t index = from >> PAGE_CACHE_SHIFT;
3376         unsigned offset = from & (PAGE_CACHE_SIZE-1);
3377         struct page *page;
3378         int ret = 0;
3379         u64 page_start;
3380         u64 page_end;
3381
3382         if ((offset & (blocksize - 1)) == 0)
3383                 goto out;
3384         ret = btrfs_delalloc_reserve_space(inode, PAGE_CACHE_SIZE);
3385         if (ret)
3386                 goto out;
3387
3388         ret = -ENOMEM;
3389 again:
3390         page = grab_cache_page(mapping, index);
3391         if (!page) {
3392                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3393                 goto out;
3394         }
3395
3396         page_start = page_offset(page);
3397         page_end = page_start + PAGE_CACHE_SIZE - 1;
3398
3399         if (!PageUptodate(page)) {
3400                 ret = btrfs_readpage(NULL, page);
3401                 lock_page(page);
3402                 if (page->mapping != mapping) {
3403                         unlock_page(page);
3404                         page_cache_release(page);
3405                         goto again;
3406                 }
3407                 if (!PageUptodate(page)) {
3408                         ret = -EIO;
3409                         goto out_unlock;
3410                 }
3411         }
3412         wait_on_page_writeback(page);
3413
3414         lock_extent_bits(io_tree, page_start, page_end, 0, &cached_state,
3415                          GFP_NOFS);
3416         set_page_extent_mapped(page);
3417
3418         ordered = btrfs_lookup_ordered_extent(inode, page_start);
3419         if (ordered) {
3420                 unlock_extent_cached(io_tree, page_start, page_end,
3421                                      &cached_state, GFP_NOFS);
3422                 unlock_page(page);
3423                 page_cache_release(page);
3424                 btrfs_start_ordered_extent(inode, ordered, 1);
3425                 btrfs_put_ordered_extent(ordered);
3426                 goto again;
3427         }
3428
3429         clear_extent_bit(&BTRFS_I(inode)->io_tree, page_start, page_end,
3430                           EXTENT_DIRTY | EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING,
3431                           0, 0, &cached_state, GFP_NOFS);
3432
3433         ret = btrfs_set_extent_delalloc(inode, page_start, page_end,
3434                                         &cached_state);
3435         if (ret) {
3436                 unlock_extent_cached(io_tree, page_start, page_end,
3437                                      &cached_state, GFP_NOFS);
3438                 goto out_unlock;
3439         }
3440
3441         ret = 0;
3442         if (offset != PAGE_CACHE_SIZE) {
3443                 kaddr = kmap(page);
3444                 memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset);
3445                 flush_dcache_page(page);
3446                 kunmap(page);
3447         }
3448         ClearPageChecked(page);
3449         set_page_dirty(page);
3450         unlock_extent_cached(io_tree, page_start, page_end, &cached_state,
3451                              GFP_NOFS);
3452
3453 out_unlock:
3454         if (ret)
3455                 btrfs_delalloc_release_space(inode, PAGE_CACHE_SIZE);
3456         unlock_page(page);
3457         page_cache_release(page);
3458 out:
3459         return ret;
3460 }
3461
3462 /*
3463  * This function puts in dummy file extents for the area we're creating a hole
3464  * for.  So if we are truncating this file to a larger size we need to insert
3465  * these file extents so that btrfs_get_extent will return a EXTENT_MAP_HOLE for
3466  * the range between oldsize and size
3467  */
3468 int btrfs_cont_expand(struct inode *inode, loff_t oldsize, loff_t size)
3469 {
3470         struct btrfs_trans_handle *trans;
3471         struct btrfs_root *root = BTRFS_I(inode)->root;
3472         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3473         struct extent_map *em = NULL;
3474         struct extent_state *cached_state = NULL;
3475         u64 mask = root->sectorsize - 1;
3476         u64 hole_start = (oldsize + mask) & ~mask;
3477         u64 block_end = (size + mask) & ~mask;
3478         u64 last_byte;
3479         u64 cur_offset;
3480         u64 hole_size;
3481         int err = 0;
3482
3483         if (size <= hole_start)
3484                 return 0;
3485
3486         while (1) {
3487                 struct btrfs_ordered_extent *ordered;
3488                 btrfs_wait_ordered_range(inode, hole_start,
3489                                          block_end - hole_start);
3490                 lock_extent_bits(io_tree, hole_start, block_end - 1, 0,
3491                                  &cached_state, GFP_NOFS);
3492                 ordered = btrfs_lookup_ordered_extent(inode, hole_start);
3493                 if (!ordered)
3494                         break;
3495                 unlock_extent_cached(io_tree, hole_start, block_end - 1,
3496                                      &cached_state, GFP_NOFS);
3497                 btrfs_put_ordered_extent(ordered);
3498         }
3499
3500         cur_offset = hole_start;
3501         while (1) {
3502                 em = btrfs_get_extent(inode, NULL, 0, cur_offset,
3503                                 block_end - cur_offset, 0);
3504                 BUG_ON(IS_ERR_OR_NULL(em));
3505                 last_byte = min(extent_map_end(em), block_end);
3506                 last_byte = (last_byte + mask) & ~mask;
3507                 if (!test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) {
3508                         u64 hint_byte = 0;
3509                         hole_size = last_byte - cur_offset;
3510
3511                         trans = btrfs_start_transaction(root, 2);
3512                         if (IS_ERR(trans)) {
3513                                 err = PTR_ERR(trans);
3514                                 break;
3515                         }
3516
3517                         err = btrfs_drop_extents(trans, inode, cur_offset,
3518                                                  cur_offset + hole_size,
3519                                                  &hint_byte, 1);
3520                         if (err)
3521                                 break;
3522
3523                         err = btrfs_insert_file_extent(trans, root,
3524                                         btrfs_ino(inode), cur_offset, 0,
3525                                         0, hole_size, 0, hole_size,
3526                                         0, 0, 0);
3527                         if (err)
3528                                 break;
3529
3530                         btrfs_drop_extent_cache(inode, hole_start,
3531                                         last_byte - 1, 0);
3532
3533                         btrfs_end_transaction(trans, root);
3534                 }
3535                 free_extent_map(em);
3536                 em = NULL;
3537                 cur_offset = last_byte;
3538                 if (cur_offset >= block_end)
3539                         break;
3540         }
3541
3542         free_extent_map(em);
3543         unlock_extent_cached(io_tree, hole_start, block_end - 1, &cached_state,
3544                              GFP_NOFS);
3545         return err;
3546 }
3547
3548 static int btrfs_setsize(struct inode *inode, loff_t newsize)
3549 {
3550         loff_t oldsize = i_size_read(inode);
3551         int ret;
3552
3553         if (newsize == oldsize)
3554                 return 0;
3555
3556         if (newsize > oldsize) {
3557                 i_size_write(inode, newsize);
3558                 btrfs_ordered_update_i_size(inode, i_size_read(inode), NULL);
3559                 truncate_pagecache(inode, oldsize, newsize);
3560                 ret = btrfs_cont_expand(inode, oldsize, newsize);
3561                 if (ret) {
3562                         btrfs_setsize(inode, oldsize);
3563                         return ret;
3564                 }
3565
3566                 mark_inode_dirty(inode);
3567         } else {
3568
3569                 /*
3570                  * We're truncating a file that used to have good data down to
3571                  * zero. Make sure it gets into the ordered flush list so that
3572                  * any new writes get down to disk quickly.
3573                  */
3574                 if (newsize == 0)
3575                         BTRFS_I(inode)->ordered_data_close = 1;
3576
3577                 /* we don't support swapfiles, so vmtruncate shouldn't fail */
3578                 truncate_setsize(inode, newsize);
3579                 ret = btrfs_truncate(inode);
3580         }
3581
3582         return ret;
3583 }
3584
3585 static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
3586 {
3587         struct inode *inode = dentry->d_inode;
3588         struct btrfs_root *root = BTRFS_I(inode)->root;
3589         int err;
3590
3591         if (btrfs_root_readonly(root))
3592                 return -EROFS;
3593
3594         err = inode_change_ok(inode, attr);
3595         if (err)
3596                 return err;
3597
3598         if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
3599                 err = btrfs_setsize(inode, attr->ia_size);
3600                 if (err)
3601                         return err;
3602         }
3603
3604         if (attr->ia_valid) {
3605                 setattr_copy(inode, attr);
3606                 mark_inode_dirty(inode);
3607
3608                 if (attr->ia_valid & ATTR_MODE)
3609                         err = btrfs_acl_chmod(inode);
3610         }
3611
3612         return err;
3613 }
3614
3615 void btrfs_evict_inode(struct inode *inode)
3616 {
3617         struct btrfs_trans_handle *trans;
3618         struct btrfs_root *root = BTRFS_I(inode)->root;
3619         unsigned long nr;
3620         int ret;
3621
3622         trace_btrfs_inode_evict(inode);
3623
3624         truncate_inode_pages(&inode->i_data, 0);
3625         if (inode->i_nlink && (btrfs_root_refs(&root->root_item) != 0 ||
3626                                is_free_space_inode(root, inode)))
3627                 goto no_delete;
3628
3629         if (is_bad_inode(inode)) {
3630                 btrfs_orphan_del(NULL, inode);
3631                 goto no_delete;
3632         }
3633         /* do we really want it for ->i_nlink > 0 and zero btrfs_root_refs? */
3634         btrfs_wait_ordered_range(inode, 0, (u64)-1);
3635
3636         if (root->fs_info->log_root_recovering) {
3637                 BUG_ON(!list_empty(&BTRFS_I(inode)->i_orphan));
3638                 goto no_delete;
3639         }
3640
3641         if (inode->i_nlink > 0) {
3642                 BUG_ON(btrfs_root_refs(&root->root_item) != 0);
3643                 goto no_delete;
3644         }
3645
3646         btrfs_i_size_write(inode, 0);
3647
3648         while (1) {
3649                 trans = btrfs_start_transaction(root, 0);
3650                 BUG_ON(IS_ERR(trans));
3651                 trans->block_rsv = root->orphan_block_rsv;
3652
3653                 ret = btrfs_block_rsv_check(trans, root,
3654                                             root->orphan_block_rsv, 0, 5);
3655                 if (ret) {
3656                         BUG_ON(ret != -EAGAIN);
3657                         ret = btrfs_commit_transaction(trans, root);
3658                         BUG_ON(ret);
3659                         continue;
3660                 }
3661
3662                 ret = btrfs_truncate_inode_items(trans, root, inode, 0, 0);
3663                 if (ret != -EAGAIN)
3664                         break;
3665
3666                 nr = trans->blocks_used;
3667                 btrfs_end_transaction(trans, root);
3668                 trans = NULL;
3669                 btrfs_btree_balance_dirty(root, nr);
3670
3671         }
3672
3673         if (ret == 0) {
3674                 ret = btrfs_orphan_del(trans, inode);
3675                 BUG_ON(ret);
3676         }
3677
3678         if (!(root == root->fs_info->tree_root ||
3679               root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID))
3680                 btrfs_return_ino(root, btrfs_ino(inode));
3681
3682         nr = trans->blocks_used;
3683         btrfs_end_transaction(trans, root);
3684         btrfs_btree_balance_dirty(root, nr);
3685 no_delete:
3686         end_writeback(inode);
3687         return;
3688 }
3689
3690 /*
3691  * this returns the key found in the dir entry in the location pointer.
3692  * If no dir entries were found, location->objectid is 0.
3693  */
3694 static int btrfs_inode_by_name(struct inode *dir, struct dentry *dentry,
3695                                struct btrfs_key *location)
3696 {
3697         const char *name = dentry->d_name.name;
3698         int namelen = dentry->d_name.len;
3699         struct btrfs_dir_item *di;
3700         struct btrfs_path *path;
3701         struct btrfs_root *root = BTRFS_I(dir)->root;
3702         int ret = 0;
3703
3704         path = btrfs_alloc_path();
3705         BUG_ON(!path);
3706
3707         di = btrfs_lookup_dir_item(NULL, root, path, btrfs_ino(dir), name,
3708                                     namelen, 0);
3709         if (IS_ERR(di))
3710                 ret = PTR_ERR(di);
3711
3712         if (IS_ERR_OR_NULL(di))
3713                 goto out_err;
3714
3715         btrfs_dir_item_key_to_cpu(path->nodes[0], di, location);
3716 out:
3717         btrfs_free_path(path);
3718         return ret;
3719 out_err:
3720         location->objectid = 0;
3721         goto out;
3722 }
3723
3724 /*
3725  * when we hit a tree root in a directory, the btrfs part of the inode
3726  * needs to be changed to reflect the root directory of the tree root.  This
3727  * is kind of like crossing a mount point.
3728  */
3729 static int fixup_tree_root_location(struct btrfs_root *root,
3730                                     struct inode *dir,
3731                                     struct dentry *dentry,
3732                                     struct btrfs_key *location,
3733                                     struct btrfs_root **sub_root)
3734 {
3735         struct btrfs_path *path;
3736         struct btrfs_root *new_root;
3737         struct btrfs_root_ref *ref;
3738         struct extent_buffer *leaf;
3739         int ret;
3740         int err = 0;
3741
3742         path = btrfs_alloc_path();
3743         if (!path) {
3744                 err = -ENOMEM;
3745                 goto out;
3746         }
3747
3748         err = -ENOENT;
3749         ret = btrfs_find_root_ref(root->fs_info->tree_root, path,
3750                                   BTRFS_I(dir)->root->root_key.objectid,
3751                                   location->objectid);
3752         if (ret) {
3753                 if (ret < 0)
3754                         err = ret;
3755                 goto out;
3756         }
3757
3758         leaf = path->nodes[0];
3759         ref = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_root_ref);
3760         if (btrfs_root_ref_dirid(leaf, ref) != btrfs_ino(dir) ||
3761             btrfs_root_ref_name_len(leaf, ref) != dentry->d_name.len)
3762                 goto out;
3763
3764         ret = memcmp_extent_buffer(leaf, dentry->d_name.name,
3765                                    (unsigned long)(ref + 1),
3766                                    dentry->d_name.len);
3767         if (ret)
3768                 goto out;
3769
3770         btrfs_release_path(path);
3771
3772         new_root = btrfs_read_fs_root_no_name(root->fs_info, location);
3773         if (IS_ERR(new_root)) {
3774                 err = PTR_ERR(new_root);
3775                 goto out;
3776         }
3777
3778         if (btrfs_root_refs(&new_root->root_item) == 0) {
3779                 err = -ENOENT;
3780                 goto out;
3781         }
3782
3783         *sub_root = new_root;
3784         location->objectid = btrfs_root_dirid(&new_root->root_item);
3785         location->type = BTRFS_INODE_ITEM_KEY;
3786         location->offset = 0;
3787         err = 0;
3788 out:
3789         btrfs_free_path(path);
3790         return err;
3791 }
3792
3793 static void inode_tree_add(struct inode *inode)
3794 {
3795         struct btrfs_root *root = BTRFS_I(inode)->root;
3796         struct btrfs_inode *entry;
3797         struct rb_node **p;
3798         struct rb_node *parent;
3799         u64 ino = btrfs_ino(inode);
3800 again:
3801         p = &root->inode_tree.rb_node;
3802         parent = NULL;
3803
3804         if (inode_unhashed(inode))
3805                 return;
3806
3807         spin_lock(&root->inode_lock);
3808         while (*p) {
3809                 parent = *p;
3810                 entry = rb_entry(parent, struct btrfs_inode, rb_node);
3811
3812                 if (ino < btrfs_ino(&entry->vfs_inode))
3813                         p = &parent->rb_left;
3814                 else if (ino > btrfs_ino(&entry->vfs_inode))
3815                         p = &parent->rb_right;
3816                 else {
3817                         WARN_ON(!(entry->vfs_inode.i_state &
3818                                   (I_WILL_FREE | I_FREEING)));
3819                         rb_erase(parent, &root->inode_tree);
3820                         RB_CLEAR_NODE(parent);
3821                         spin_unlock(&root->inode_lock);
3822                         goto again;
3823                 }
3824         }
3825         rb_link_node(&BTRFS_I(inode)->rb_node, parent, p);
3826         rb_insert_color(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3827         spin_unlock(&root->inode_lock);
3828 }
3829
3830 static void inode_tree_del(struct inode *inode)
3831 {
3832         struct btrfs_root *root = BTRFS_I(inode)->root;
3833         int empty = 0;
3834
3835         spin_lock(&root->inode_lock);
3836         if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
3837                 rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
3838                 RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
3839                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3840         }
3841         spin_unlock(&root->inode_lock);
3842
3843         /*
3844          * Free space cache has inodes in the tree root, but the tree root has a
3845          * root_refs of 0, so this could end up dropping the tree root as a
3846          * snapshot, so we need the extra !root->fs_info->tree_root check to
3847          * make sure we don't drop it.
3848          */
3849         if (empty && btrfs_root_refs(&root->root_item) == 0 &&
3850             root != root->fs_info->tree_root) {
3851                 synchronize_srcu(&root->fs_info->subvol_srcu);
3852                 spin_lock(&root->inode_lock);
3853                 empty = RB_EMPTY_ROOT(&root->inode_tree);
3854                 spin_unlock(&root->inode_lock);
3855                 if (empty)
3856                         btrfs_add_dead_root(root);
3857         }
3858 }
3859
3860 int btrfs_invalidate_inodes(struct btrfs_root *root)
3861 {
3862         struct rb_node *node;
3863         struct rb_node *prev;
3864         struct btrfs_inode *entry;
3865         struct inode *inode;
3866         u64 objectid = 0;
3867
3868         WARN_ON(btrfs_root_refs(&root->root_item) != 0);
3869
3870         spin_lock(&root->inode_lock);
3871 again:
3872         node = root->inode_tree.rb_node;
3873         prev = NULL;
3874         while (node) {
3875                 prev = node;
3876                 entry = rb_entry(node, struct btrfs_inode, rb_node);
3877
3878                 if (objectid < btrfs_ino(&entry->vfs_inode))
3879                         node = node->rb_left;
3880                 else if (objectid > btrfs_ino(&entry->vfs_inode))
3881                         node = node->rb_right;
3882                 else
3883                         break;
3884         }
3885         if (!node) {
3886                 while (prev) {
3887                         entry = rb_entry(prev, struct btrfs_inode, rb_node);
3888                         if (objectid <= btrfs_ino(&entry->vfs_inode)) {
3889                                 node = prev;
3890                                 break;
3891                         }
3892                         prev = rb_next(prev);
3893                 }
3894         }
3895         while (node) {
3896                 entry = rb_entry(node, struct btrfs_inode, rb_node);
3897                 objectid = btrfs_ino(&entry->vfs_inode) + 1;
3898                 inode = igrab(&entry->vfs_inode);
3899                 if (inode) {
3900                         spin_unlock(&root->inode_lock);
3901                         if (atomic_read(&inode->i_count) > 1)
3902                                 d_prune_aliases(inode);
3903                         /*
3904                          * btrfs_drop_inode will have it removed from
3905                          * the inode cache when its usage count
3906                          * hits zero.
3907                          */
3908                         iput(inode);
3909                         cond_resched();
3910                         spin_lock(&root->inode_lock);
3911                         goto again;
3912                 }
3913
3914                 if (cond_resched_lock(&root->inode_lock))
3915                         goto again;
3916
3917                 node = rb_next(node);
3918         }
3919         spin_unlock(&root->inode_lock);
3920         return 0;
3921 }
3922
3923 static int btrfs_init_locked_inode(struct inode *inode, void *p)
3924 {
3925         struct btrfs_iget_args *args = p;
3926         inode->i_ino = args->ino;
3927         BTRFS_I(inode)->root = args->root;
3928         btrfs_set_inode_space_info(args->root, inode);
3929         return 0;
3930 }
3931
3932 static int btrfs_find_actor(struct inode *inode, void *opaque)
3933 {
3934         struct btrfs_iget_args *args = opaque;
3935         return args->ino == btrfs_ino(inode) &&
3936                 args->root == BTRFS_I(inode)->root;
3937 }
3938
3939 static struct inode *btrfs_iget_locked(struct super_block *s,
3940                                        u64 objectid,
3941                                        struct btrfs_root *root)
3942 {
3943         struct inode *inode;
3944         struct btrfs_iget_args args;
3945         args.ino = objectid;
3946         args.root = root;
3947
3948         inode = iget5_locked(s, objectid, btrfs_find_actor,
3949                              btrfs_init_locked_inode,
3950                              (void *)&args);
3951         return inode;
3952 }
3953
3954 /* Get an inode object given its location and corresponding root.
3955  * Returns in *is_new if the inode was read from disk
3956  */
3957 struct inode *btrfs_iget(struct super_block *s, struct btrfs_key *location,
3958                          struct btrfs_root *root, int *new)
3959 {
3960         struct inode *inode;
3961
3962         inode = btrfs_iget_locked(s, location->objectid, root);
3963         if (!inode)
3964                 return ERR_PTR(-ENOMEM);
3965
3966         if (inode->i_state & I_NEW) {
3967                 BTRFS_I(inode)->root = root;
3968                 memcpy(&BTRFS_I(inode)->location, location, sizeof(*location));
3969                 btrfs_read_locked_inode(inode);
3970                 inode_tree_add(inode);
3971                 unlock_new_inode(inode);
3972                 if (new)
3973                         *new = 1;
3974         }
3975
3976         return inode;
3977 }
3978
3979 static struct inode *new_simple_dir(struct super_block *s,
3980                                     struct btrfs_key *key,
3981                                     struct btrfs_root *root)
3982 {
3983         struct inode *inode = new_inode(s);
3984
3985         if (!inode)
3986                 return ERR_PTR(-ENOMEM);
3987
3988         BTRFS_I(inode)->root = root;
3989         memcpy(&BTRFS_I(inode)->location, key, sizeof(*key));
3990         BTRFS_I(inode)->dummy_inode = 1;
3991
3992         inode->i_ino = BTRFS_EMPTY_SUBVOL_DIR_OBJECTID;
3993         inode->i_op = &simple_dir_inode_operations;
3994         inode->i_fop = &simple_dir_operations;
3995         inode->i_mode = S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO;
3996         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
3997
3998         return inode;
3999 }
4000
4001 struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
4002 {
4003         struct inode *inode;
4004         struct btrfs_root *root = BTRFS_I(dir)->root;
4005         struct btrfs_root *sub_root = root;
4006         struct btrfs_key location;
4007         int index;
4008         int ret;
4009
4010         if (dentry->d_name.len > BTRFS_NAME_LEN)
4011                 return ERR_PTR(-ENAMETOOLONG);
4012
4013         ret = btrfs_inode_by_name(dir, dentry, &location);
4014
4015         if (ret < 0)
4016                 return ERR_PTR(ret);
4017
4018         if (location.objectid == 0)
4019                 return NULL;
4020
4021         if (location.type == BTRFS_INODE_ITEM_KEY) {
4022                 inode = btrfs_iget(dir->i_sb, &location, root, NULL);
4023                 return inode;
4024         }
4025
4026         BUG_ON(location.type != BTRFS_ROOT_ITEM_KEY);
4027
4028         index = srcu_read_lock(&root->fs_info->subvol_srcu);
4029         ret = fixup_tree_root_location(root, dir, dentry,
4030                                        &location, &sub_root);
4031         if (ret < 0) {
4032                 if (ret != -ENOENT)
4033                         inode = ERR_PTR(ret);
4034                 else
4035                         inode = new_simple_dir(dir->i_sb, &location, sub_root);
4036         } else {
4037                 inode = btrfs_iget(dir->i_sb, &location, sub_root, NULL);
4038         }
4039         srcu_read_unlock(&root->fs_info->subvol_srcu, index);
4040
4041         if (!IS_ERR(inode) && root != sub_root) {
4042                 down_read(&root->fs_info->cleanup_work_sem);
4043                 if (!(inode->i_sb->s_flags & MS_RDONLY))
4044                         ret = btrfs_orphan_cleanup(sub_root);
4045                 up_read(&root->fs_info->cleanup_work_sem);
4046                 if (ret)
4047                         inode = ERR_PTR(ret);
4048         }
4049
4050         return inode;
4051 }
4052
4053 static int btrfs_dentry_delete(const struct dentry *dentry)
4054 {
4055         struct btrfs_root *root;
4056
4057         if (!dentry->d_inode && !IS_ROOT(dentry))
4058                 dentry = dentry->d_parent;
4059
4060         if (dentry->d_inode) {
4061                 root = BTRFS_I(dentry->d_inode)->root;
4062                 if (btrfs_root_refs(&root->root_item) == 0)
4063                         return 1;
4064         }
4065         return 0;
4066 }
4067
4068 static struct dentry *btrfs_lookup(struct inode *dir, struct dentry *dentry,
4069                                    struct nameidata *nd)
4070 {
4071         struct inode *inode;
4072
4073         inode = btrfs_lookup_dentry(dir, dentry);
4074         if (IS_ERR(inode))
4075                 return ERR_CAST(inode);
4076
4077         return d_splice_alias(inode, dentry);
4078 }
4079
4080 unsigned char btrfs_filetype_table[] = {
4081         DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK
4082 };
4083
4084 static int btrfs_real_readdir(struct file *filp, void *dirent,
4085                               filldir_t filldir)
4086 {
4087         struct inode *inode = filp->f_dentry->d_inode;
4088         struct btrfs_root *root = BTRFS_I(inode)->root;
4089         struct btrfs_item *item;
4090         struct btrfs_dir_item *di;
4091         struct btrfs_key key;
4092         struct btrfs_key found_key;
4093         struct btrfs_path *path;
4094         struct list_head ins_list;
4095         struct list_head del_list;
4096         int ret;
4097         struct extent_buffer *leaf;
4098         int slot;
4099         unsigned char d_type;
4100         int over = 0;
4101         u32 di_cur;
4102         u32 di_total;
4103         u32 di_len;
4104         int key_type = BTRFS_DIR_INDEX_KEY;
4105         char tmp_name[32];
4106         char *name_ptr;
4107         int name_len;
4108         int is_curr = 0;        /* filp->f_pos points to the current index? */
4109
4110         /* FIXME, use a real flag for deciding about the key type */
4111         if (root->fs_info->tree_root == root)
4112                 key_type = BTRFS_DIR_ITEM_KEY;
4113
4114         /* special case for "." */
4115         if (filp->f_pos == 0) {
4116                 over = filldir(dirent, ".", 1, 1, btrfs_ino(inode), DT_DIR);
4117                 if (over)
4118                         return 0;
4119                 filp->f_pos = 1;
4120         }
4121         /* special case for .., just use the back ref */
4122         if (filp->f_pos == 1) {
4123                 u64 pino = parent_ino(filp->f_path.dentry);
4124                 over = filldir(dirent, "..", 2,
4125                                2, pino, DT_DIR);
4126                 if (over)
4127                         return 0;
4128                 filp->f_pos = 2;
4129         }
4130         path = btrfs_alloc_path();
4131         if (!path)
4132                 return -ENOMEM;
4133
4134         path->reada = 1;
4135
4136         if (key_type == BTRFS_DIR_INDEX_KEY) {
4137                 INIT_LIST_HEAD(&ins_list);
4138                 INIT_LIST_HEAD(&del_list);
4139                 btrfs_get_delayed_items(inode, &ins_list, &del_list);
4140         }
4141
4142         btrfs_set_key_type(&key, key_type);
4143         key.offset = filp->f_pos;
4144         key.objectid = btrfs_ino(inode);
4145
4146         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4147         if (ret < 0)
4148                 goto err;
4149
4150         while (1) {
4151                 leaf = path->nodes[0];
4152                 slot = path->slots[0];
4153                 if (slot >= btrfs_header_nritems(leaf)) {
4154                         ret = btrfs_next_leaf(root, path);
4155                         if (ret < 0)
4156                                 goto err;
4157                         else if (ret > 0)
4158                                 break;
4159                         continue;
4160                 }
4161
4162                 item = btrfs_item_nr(leaf, slot);
4163                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
4164
4165                 if (found_key.objectid != key.objectid)
4166                         break;
4167                 if (btrfs_key_type(&found_key) != key_type)
4168                         break;
4169                 if (found_key.offset < filp->f_pos)
4170                         goto next;
4171                 if (key_type == BTRFS_DIR_INDEX_KEY &&
4172                     btrfs_should_delete_dir_index(&del_list,
4173                                                   found_key.offset))
4174                         goto next;
4175
4176                 filp->f_pos = found_key.offset;
4177                 is_curr = 1;
4178
4179                 di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
4180                 di_cur = 0;
4181                 di_total = btrfs_item_size(leaf, item);
4182
4183                 while (di_cur < di_total) {
4184                         struct btrfs_key location;
4185
4186                         if (verify_dir_item(root, leaf, di))
4187                                 break;
4188
4189                         name_len = btrfs_dir_name_len(leaf, di);
4190                         if (name_len <= sizeof(tmp_name)) {
4191                                 name_ptr = tmp_name;
4192                         } else {
4193                                 name_ptr = kmalloc(name_len, GFP_NOFS);
4194                                 if (!name_ptr) {
4195                                         ret = -ENOMEM;
4196                                         goto err;
4197                                 }
4198                         }
4199                         read_extent_buffer(leaf, name_ptr,
4200                                            (unsigned long)(di + 1), name_len);
4201
4202                         d_type = btrfs_filetype_table[btrfs_dir_type(leaf, di)];
4203                         btrfs_dir_item_key_to_cpu(leaf, di, &location);
4204
4205                         /* is this a reference to our own snapshot? If so
4206                          * skip it
4207                          */
4208                         if (location.type == BTRFS_ROOT_ITEM_KEY &&
4209                             location.objectid == root->root_key.objectid) {
4210                                 over = 0;
4211                                 goto skip;
4212                         }
4213                         over = filldir(dirent, name_ptr, name_len,
4214                                        found_key.offset, location.objectid,
4215                                        d_type);
4216
4217 skip:
4218                         if (name_ptr != tmp_name)
4219                                 kfree(name_ptr);
4220
4221                         if (over)
4222                                 goto nopos;
4223                         di_len = btrfs_dir_name_len(leaf, di) +
4224                                  btrfs_dir_data_len(leaf, di) + sizeof(*di);
4225                         di_cur += di_len;
4226                         di = (struct btrfs_dir_item *)((char *)di + di_len);
4227                 }
4228 next:
4229                 path->slots[0]++;
4230         }
4231
4232         if (key_type == BTRFS_DIR_INDEX_KEY) {
4233                 if (is_curr)
4234                         filp->f_pos++;
4235                 ret = btrfs_readdir_delayed_dir_index(filp, dirent, filldir,
4236                                                       &ins_list);
4237                 if (ret)
4238                         goto nopos;
4239         }
4240
4241         /* Reached end of directory/root. Bump pos past the last item. */
4242         if (key_type == BTRFS_DIR_INDEX_KEY)
4243                 /*
4244                  * 32-bit glibc will use getdents64, but then strtol -
4245                  * so the last number we can serve is this.
4246                  */
4247                 filp->f_pos = 0x7fffffff;
4248         else
4249                 filp->f_pos++;
4250 nopos:
4251         ret = 0;
4252 err:
4253         if (key_type == BTRFS_DIR_INDEX_KEY)
4254                 btrfs_put_delayed_items(&ins_list, &del_list);
4255         btrfs_free_path(path);
4256         return ret;
4257 }
4258
4259 int btrfs_write_inode(struct inode *inode, struct writeback_control *wbc)
4260 {
4261         struct btrfs_root *root = BTRFS_I(inode)->root;
4262         struct btrfs_trans_handle *trans;
4263         int ret = 0;
4264         bool nolock = false;
4265
4266         if (BTRFS_I(inode)->dummy_inode)
4267                 return 0;
4268
4269         if (btrfs_fs_closing(root->fs_info) && is_free_space_inode(root, inode))
4270                 nolock = true;
4271
4272         if (wbc->sync_mode == WB_SYNC_ALL) {
4273                 if (nolock)
4274                         trans = btrfs_join_transaction_nolock(root);
4275                 else
4276                         trans = btrfs_join_transaction(root);
4277                 if (IS_ERR(trans))
4278                         return PTR_ERR(trans);
4279                 if (nolock)
4280                         ret = btrfs_end_transaction_nolock(trans, root);
4281                 else
4282                         ret = btrfs_commit_transaction(trans, root);
4283         }
4284         return ret;
4285 }
4286
4287 /*
4288  * This is somewhat expensive, updating the tree every time the
4289  * inode changes.  But, it is most likely to find the inode in cache.
4290  * FIXME, needs more benchmarking...there are no reasons other than performance
4291  * to keep or drop this code.
4292  */
4293 void btrfs_dirty_inode(struct inode *inode, int flags)
4294 {
4295         struct btrfs_root *root = BTRFS_I(inode)->root;
4296         struct btrfs_trans_handle *trans;
4297         int ret;
4298
4299         if (BTRFS_I(inode)->dummy_inode)
4300                 return;
4301
4302         trans = btrfs_join_transaction(root);
4303         BUG_ON(IS_ERR(trans));
4304
4305         ret = btrfs_update_inode(trans, root, inode);
4306         if (ret && ret == -ENOSPC) {
4307                 /* whoops, lets try again with the full transaction */
4308                 btrfs_end_transaction(trans, root);
4309                 trans = btrfs_start_transaction(root, 1);
4310                 if (IS_ERR(trans)) {
4311                         printk_ratelimited(KERN_ERR "btrfs: fail to "
4312                                        "dirty  inode %llu error %ld\n",
4313                                        (unsigned long long)btrfs_ino(inode),
4314                                        PTR_ERR(trans));
4315                         return;
4316                 }
4317
4318                 ret = btrfs_update_inode(trans, root, inode);
4319                 if (ret) {
4320                         printk_ratelimited(KERN_ERR "btrfs: fail to "
4321                                        "dirty  inode %llu error %d\n",
4322                                        (unsigned long long)btrfs_ino(inode),
4323                                        ret);
4324                 }
4325         }
4326         btrfs_end_transaction(trans, root);
4327         if (BTRFS_I(inode)->delayed_node)
4328                 btrfs_balance_delayed_items(root);
4329 }
4330
4331 /*
4332  * find the highest existing sequence number in a directory
4333  * and then set the in-memory index_cnt variable to reflect
4334  * free sequence numbers
4335  */
4336 static int btrfs_set_inode_index_count(struct inode *inode)
4337 {
4338         struct btrfs_root *root = BTRFS_I(inode)->root;
4339         struct btrfs_key key, found_key;
4340         struct btrfs_path *path;
4341         struct extent_buffer *leaf;
4342         int ret;
4343
4344         key.objectid = btrfs_ino(inode);
4345         btrfs_set_key_type(&key, BTRFS_DIR_INDEX_KEY);
4346         key.offset = (u64)-1;
4347
4348         path = btrfs_alloc_path();
4349         if (!path)
4350                 return -ENOMEM;
4351
4352         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
4353         if (ret < 0)
4354                 goto out;
4355         /* FIXME: we should be able to handle this */
4356         if (ret == 0)
4357                 goto out;
4358         ret = 0;
4359
4360         /*
4361          * MAGIC NUMBER EXPLANATION:
4362          * since we search a directory based on f_pos we have to start at 2
4363          * since '.' and '..' have f_pos of 0 and 1 respectively, so everybody
4364          * else has to start at 2
4365          */
4366         if (path->slots[0] == 0) {
4367                 BTRFS_I(inode)->index_cnt = 2;
4368                 goto out;
4369         }
4370
4371         path->slots[0]--;
4372
4373         leaf = path->nodes[0];
4374         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4375
4376         if (found_key.objectid != btrfs_ino(inode) ||
4377             btrfs_key_type(&found_key) != BTRFS_DIR_INDEX_KEY) {
4378                 BTRFS_I(inode)->index_cnt = 2;
4379                 goto out;
4380         }
4381
4382         BTRFS_I(inode)->index_cnt = found_key.offset + 1;
4383 out:
4384         btrfs_free_path(path);
4385         return ret;
4386 }
4387
4388 /*
4389  * helper to find a free sequence number in a given directory.  This current
4390  * code is very simple, later versions will do smarter things in the btree
4391  */
4392 int btrfs_set_inode_index(struct inode *dir, u64 *index)
4393 {
4394         int ret = 0;
4395
4396         if (BTRFS_I(dir)->index_cnt == (u64)-1) {
4397                 ret = btrfs_inode_delayed_dir_index_count(dir);
4398                 if (ret) {
4399                         ret = btrfs_set_inode_index_count(dir);
4400                         if (ret)
4401                                 return ret;
4402                 }
4403         }
4404
4405         *index = BTRFS_I(dir)->index_cnt;
4406         BTRFS_I(dir)->index_cnt++;
4407
4408         return ret;
4409 }
4410
4411 static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
4412                                      struct btrfs_root *root,
4413                                      struct inode *dir,
4414                                      const char *name, int name_len,
4415                                      u64 ref_objectid, u64 objectid, int mode,
4416                                      u64 *index)
4417 {
4418         struct inode *inode;
4419         struct btrfs_inode_item *inode_item;
4420         struct btrfs_key *location;
4421         struct btrfs_path *path;
4422         struct btrfs_inode_ref *ref;
4423         struct btrfs_key key[2];
4424         u32 sizes[2];
4425         unsigned long ptr;
4426         int ret;
4427         int owner;
4428
4429         path = btrfs_alloc_path();
4430         BUG_ON(!path);
4431
4432         inode = new_inode(root->fs_info->sb);
4433         if (!inode) {
4434                 btrfs_free_path(path);
4435                 return ERR_PTR(-ENOMEM);
4436         }
4437
4438         /*
4439          * we have to initialize this early, so we can reclaim the inode
4440          * number if we fail afterwards in this function.
4441          */
4442         inode->i_ino = objectid;
4443
4444         if (dir) {
4445                 trace_btrfs_inode_request(dir);
4446
4447                 ret = btrfs_set_inode_index(dir, index);
4448                 if (ret) {
4449                         btrfs_free_path(path);
4450                         iput(inode);
4451                         return ERR_PTR(ret);
4452                 }
4453         }
4454         /*
4455          * index_cnt is ignored for everything but a dir,
4456          * btrfs_get_inode_index_count has an explanation for the magic
4457          * number
4458          */
4459         BTRFS_I(inode)->index_cnt = 2;
4460         BTRFS_I(inode)->root = root;
4461         BTRFS_I(inode)->generation = trans->transid;
4462         inode->i_generation = BTRFS_I(inode)->generation;
4463         btrfs_set_inode_space_info(root, inode);
4464
4465         if (mode & S_IFDIR)
4466                 owner = 0;
4467         else
4468                 owner = 1;
4469
4470         key[0].objectid = objectid;
4471         btrfs_set_key_type(&key[0], BTRFS_INODE_ITEM_KEY);
4472         key[0].offset = 0;
4473
4474         key[1].objectid = objectid;
4475         btrfs_set_key_type(&key[1], BTRFS_INODE_REF_KEY);
4476         key[1].offset = ref_objectid;
4477
4478         sizes[0] = sizeof(struct btrfs_inode_item);
4479         sizes[1] = name_len + sizeof(*ref);
4480
4481         path->leave_spinning = 1;
4482         ret = btrfs_insert_empty_items(trans, root, path, key, sizes, 2);
4483         if (ret != 0)
4484                 goto fail;
4485
4486         inode_init_owner(inode, dir, mode);
4487         inode_set_bytes(inode, 0);
4488         inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
4489         inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
4490                                   struct btrfs_inode_item);
4491         fill_inode_item(trans, path->nodes[0], inode_item, inode);
4492
4493         ref = btrfs_item_ptr(path->nodes[0], path->slots[0] + 1,
4494                              struct btrfs_inode_ref);
4495         btrfs_set_inode_ref_name_len(path->nodes[0], ref, name_len);
4496         btrfs_set_inode_ref_index(path->nodes[0], ref, *index);
4497         ptr = (unsigned long)(ref + 1);
4498         write_extent_buffer(path->nodes[0], name, ptr, name_len);
4499
4500         btrfs_mark_buffer_dirty(path->nodes[0]);
4501         btrfs_free_path(path);
4502
4503         location = &BTRFS_I(inode)->location;
4504         location->objectid = objectid;
4505         location->offset = 0;
4506         btrfs_set_key_type(location, BTRFS_INODE_ITEM_KEY);
4507
4508         btrfs_inherit_iflags(inode, dir);
4509
4510         if ((mode & S_IFREG)) {
4511                 if (btrfs_test_opt(root, NODATASUM))
4512                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
4513                 if (btrfs_test_opt(root, NODATACOW) ||
4514                     (BTRFS_I(dir)->flags & BTRFS_INODE_NODATACOW))
4515                         BTRFS_I(inode)->flags |= BTRFS_INODE_NODATACOW;
4516         }
4517
4518         insert_inode_hash(inode);
4519         inode_tree_add(inode);
4520
4521         trace_btrfs_inode_new(inode);
4522
4523         return inode;
4524 fail:
4525         if (dir)
4526                 BTRFS_I(dir)->index_cnt--;
4527         btrfs_free_path(path);
4528         iput(inode);
4529         return ERR_PTR(ret);
4530 }
4531
4532 static inline u8 btrfs_inode_type(struct inode *inode)
4533 {
4534         return btrfs_type_by_mode[(inode->i_mode & S_IFMT) >> S_SHIFT];
4535 }
4536
4537 /*
4538  * utility function to add 'inode' into 'parent_inode' with
4539  * a give name and a given sequence number.
4540  * if 'add_backref' is true, also insert a backref from the
4541  * inode to the parent directory.
4542  */
4543 int btrfs_add_link(struct btrfs_trans_handle *trans,
4544                    struct inode *parent_inode, struct inode *inode,
4545                    const char *name, int name_len, int add_backref, u64 index)
4546 {
4547         int ret = 0;
4548         struct btrfs_key key;
4549         struct btrfs_root *root = BTRFS_I(parent_inode)->root;
4550         u64 ino = btrfs_ino(inode);
4551         u64 parent_ino = btrfs_ino(parent_inode);
4552
4553         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4554                 memcpy(&key, &BTRFS_I(inode)->root->root_key, sizeof(key));
4555         } else {
4556                 key.objectid = ino;
4557                 btrfs_set_key_type(&key, BTRFS_INODE_ITEM_KEY);
4558                 key.offset = 0;
4559         }
4560
4561         if (unlikely(ino == BTRFS_FIRST_FREE_OBJECTID)) {
4562                 ret = btrfs_add_root_ref(trans, root->fs_info->tree_root,
4563                                          key.objectid, root->root_key.objectid,
4564                                          parent_ino, index, name, name_len);
4565         } else if (add_backref) {
4566                 ret = btrfs_insert_inode_ref(trans, root, name, name_len, ino,
4567                                              parent_ino, index);
4568         }
4569
4570         if (ret == 0) {
4571                 ret = btrfs_insert_dir_item(trans, root, name, name_len,
4572                                             parent_inode, &key,
4573                                             btrfs_inode_type(inode), index);
4574                 BUG_ON(ret);
4575
4576                 btrfs_i_size_write(parent_inode, parent_inode->i_size +
4577                                    name_len * 2);
4578                 parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
4579                 ret = btrfs_update_inode(trans, root, parent_inode);
4580         }
4581         return ret;
4582 }
4583
4584 static int btrfs_add_nondir(struct btrfs_trans_handle *trans,
4585                             struct inode *dir, struct dentry *dentry,
4586                             struct inode *inode, int backref, u64 index)
4587 {
4588         int err = btrfs_add_link(trans, dir, inode,
4589                                  dentry->d_name.name, dentry->d_name.len,
4590                                  backref, index);
4591         if (!err) {
4592                 d_instantiate(dentry, inode);
4593                 return 0;
4594         }
4595         if (err > 0)
4596                 err = -EEXIST;
4597         return err;
4598 }
4599
4600 static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
4601                         int mode, dev_t rdev)
4602 {
4603         struct btrfs_trans_handle *trans;
4604         struct btrfs_root *root = BTRFS_I(dir)->root;
4605         struct inode *inode = NULL;
4606         int err;
4607         int drop_inode = 0;
4608         u64 objectid;
4609         unsigned long nr = 0;
4610         u64 index = 0;
4611
4612         if (!new_valid_dev(rdev))
4613                 return -EINVAL;
4614
4615         /*
4616          * 2 for inode item and ref
4617          * 2 for dir items
4618          * 1 for xattr if selinux is on
4619          */
4620         trans = btrfs_start_transaction(root, 5);
4621         if (IS_ERR(trans))
4622                 return PTR_ERR(trans);
4623
4624         err = btrfs_find_free_ino(root, &objectid);
4625         if (err)
4626                 goto out_unlock;
4627
4628         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4629                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4630                                 mode, &index);
4631         if (IS_ERR(inode)) {
4632                 err = PTR_ERR(inode);
4633                 goto out_unlock;
4634         }
4635
4636         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4637         if (err) {
4638                 drop_inode = 1;
4639                 goto out_unlock;
4640         }
4641
4642         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4643         if (err)
4644                 drop_inode = 1;
4645         else {
4646                 inode->i_op = &btrfs_special_inode_operations;
4647                 init_special_inode(inode, inode->i_mode, rdev);
4648                 btrfs_update_inode(trans, root, inode);
4649         }
4650 out_unlock:
4651         nr = trans->blocks_used;
4652         btrfs_end_transaction_throttle(trans, root);
4653         btrfs_btree_balance_dirty(root, nr);
4654         if (drop_inode) {
4655                 inode_dec_link_count(inode);
4656                 iput(inode);
4657         }
4658         return err;
4659 }
4660
4661 static int btrfs_create(struct inode *dir, struct dentry *dentry,
4662                         int mode, struct nameidata *nd)
4663 {
4664         struct btrfs_trans_handle *trans;
4665         struct btrfs_root *root = BTRFS_I(dir)->root;
4666         struct inode *inode = NULL;
4667         int drop_inode = 0;
4668         int err;
4669         unsigned long nr = 0;
4670         u64 objectid;
4671         u64 index = 0;
4672
4673         /*
4674          * 2 for inode item and ref
4675          * 2 for dir items
4676          * 1 for xattr if selinux is on
4677          */
4678         trans = btrfs_start_transaction(root, 5);
4679         if (IS_ERR(trans))
4680                 return PTR_ERR(trans);
4681
4682         err = btrfs_find_free_ino(root, &objectid);
4683         if (err)
4684                 goto out_unlock;
4685
4686         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4687                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4688                                 mode, &index);
4689         if (IS_ERR(inode)) {
4690                 err = PTR_ERR(inode);
4691                 goto out_unlock;
4692         }
4693
4694         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4695         if (err) {
4696                 drop_inode = 1;
4697                 goto out_unlock;
4698         }
4699
4700         err = btrfs_add_nondir(trans, dir, dentry, inode, 0, index);
4701         if (err)
4702                 drop_inode = 1;
4703         else {
4704                 inode->i_mapping->a_ops = &btrfs_aops;
4705                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
4706                 inode->i_fop = &btrfs_file_operations;
4707                 inode->i_op = &btrfs_file_inode_operations;
4708                 BTRFS_I(inode)->io_tree.ops = &btrfs_extent_io_ops;
4709         }
4710 out_unlock:
4711         nr = trans->blocks_used;
4712         btrfs_end_transaction_throttle(trans, root);
4713         if (drop_inode) {
4714                 inode_dec_link_count(inode);
4715                 iput(inode);
4716         }
4717         btrfs_btree_balance_dirty(root, nr);
4718         return err;
4719 }
4720
4721 static int btrfs_link(struct dentry *old_dentry, struct inode *dir,
4722                       struct dentry *dentry)
4723 {
4724         struct btrfs_trans_handle *trans;
4725         struct btrfs_root *root = BTRFS_I(dir)->root;
4726         struct inode *inode = old_dentry->d_inode;
4727         u64 index;
4728         unsigned long nr = 0;
4729         int err;
4730         int drop_inode = 0;
4731
4732         /* do not allow sys_link's with other subvols of the same device */
4733         if (root->objectid != BTRFS_I(inode)->root->objectid)
4734                 return -EXDEV;
4735
4736         if (inode->i_nlink == ~0U)
4737                 return -EMLINK;
4738
4739         err = btrfs_set_inode_index(dir, &index);
4740         if (err)
4741                 goto fail;
4742
4743         /*
4744          * 2 items for inode and inode ref
4745          * 2 items for dir items
4746          * 1 item for parent inode
4747          */
4748         trans = btrfs_start_transaction(root, 5);
4749         if (IS_ERR(trans)) {
4750                 err = PTR_ERR(trans);
4751                 goto fail;
4752         }
4753
4754         btrfs_inc_nlink(inode);
4755         inode->i_ctime = CURRENT_TIME;
4756         ihold(inode);
4757
4758         err = btrfs_add_nondir(trans, dir, dentry, inode, 1, index);
4759
4760         if (err) {
4761                 drop_inode = 1;
4762         } else {
4763                 struct dentry *parent = dget_parent(dentry);
4764                 err = btrfs_update_inode(trans, root, inode);
4765                 BUG_ON(err);
4766                 btrfs_log_new_name(trans, inode, NULL, parent);
4767                 dput(parent);
4768         }
4769
4770         nr = trans->blocks_used;
4771         btrfs_end_transaction_throttle(trans, root);
4772 fail:
4773         if (drop_inode) {
4774                 inode_dec_link_count(inode);
4775                 iput(inode);
4776         }
4777         btrfs_btree_balance_dirty(root, nr);
4778         return err;
4779 }
4780
4781 static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
4782 {
4783         struct inode *inode = NULL;
4784         struct btrfs_trans_handle *trans;
4785         struct btrfs_root *root = BTRFS_I(dir)->root;
4786         int err = 0;
4787         int drop_on_err = 0;
4788         u64 objectid = 0;
4789         u64 index = 0;
4790         unsigned long nr = 1;
4791
4792         /*
4793          * 2 items for inode and ref
4794          * 2 items for dir items
4795          * 1 for xattr if selinux is on
4796          */
4797         trans = btrfs_start_transaction(root, 5);
4798         if (IS_ERR(trans))
4799                 return PTR_ERR(trans);
4800
4801         err = btrfs_find_free_ino(root, &objectid);
4802         if (err)
4803                 goto out_fail;
4804
4805         inode = btrfs_new_inode(trans, root, dir, dentry->d_name.name,
4806                                 dentry->d_name.len, btrfs_ino(dir), objectid,
4807                                 S_IFDIR | mode, &index);
4808         if (IS_ERR(inode)) {
4809                 err = PTR_ERR(inode);
4810                 goto out_fail;
4811         }
4812
4813         drop_on_err = 1;
4814
4815         err = btrfs_init_inode_security(trans, inode, dir, &dentry->d_name);
4816         if (err)
4817                 goto out_fail;
4818
4819         inode->i_op = &btrfs_dir_inode_operations;
4820         inode->i_fop = &btrfs_dir_file_operations;
4821
4822         btrfs_i_size_write(inode, 0);
4823         err = btrfs_update_inode(trans, root, inode);
4824         if (err)
4825                 goto out_fail;
4826
4827         err = btrfs_add_link(trans, dir, inode, dentry->d_name.name,
4828                              dentry->d_name.len, 0, index);
4829         if (err)
4830                 goto out_fail;
4831
4832         d_instantiate(dentry, inode);
4833         drop_on_err = 0;
4834
4835 out_fail:
4836         nr = trans->blocks_used;
4837         btrfs_end_transaction_throttle(trans, root);
4838         if (drop_on_err)
4839                 iput(inode);
4840         btrfs_btree_balance_dirty(root, nr);
4841         return err;
4842 }
4843
4844 /* helper for btfs_get_extent.  Given an existing extent in the tree,
4845  * and an extent that you want to insert, deal with overlap and insert
4846  * the new extent into the tree.
4847  */
4848 static int merge_extent_mapping(struct extent_map_tree *em_tree,
4849                                 struct extent_map *existing,
4850                                 struct extent_map *em,
4851                                 u64 map_start, u64 map_len)
4852 {
4853         u64 start_diff;
4854
4855         BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
4856         start_diff = map_start - em->start;
4857         em->start = map_start;
4858         em->len = map_len;
4859         if (em->block_start < EXTENT_MAP_LAST_BYTE &&
4860             !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
4861                 em->block_start += start_diff;
4862                 em->block_len -= start_diff;
4863         }
4864         return add_extent_mapping(em_tree, em);
4865 }
4866
4867 static noinline int uncompress_inline(struct btrfs_path *path,
4868                                       struct inode *inode, struct page *page,
4869                                       size_t pg_offset, u64 extent_offset,
4870                                       struct btrfs_file_extent_item *item)
4871 {
4872         int ret;
4873         struct extent_buffer *leaf = path->nodes[0];
4874         char *tmp;
4875         size_t max_size;
4876         unsigned long inline_size;
4877         unsigned long ptr;
4878         int compress_type;
4879
4880         WARN_ON(pg_offset != 0);
4881         compress_type = btrfs_file_extent_compression(leaf, item);
4882         max_size = btrfs_file_extent_ram_bytes(leaf, item);
4883         inline_size = btrfs_file_extent_inline_item_len(leaf,
4884                                         btrfs_item_nr(leaf, path->slots[0]));
4885         tmp = kmalloc(inline_size, GFP_NOFS);
4886         if (!tmp)
4887                 return -ENOMEM;
4888         ptr = btrfs_file_extent_inline_start(item);
4889
4890         read_extent_buffer(leaf, tmp, ptr, inline_size);
4891
4892         max_size = min_t(unsigned long, PAGE_CACHE_SIZE, max_size);
4893         ret = btrfs_decompress(compress_type, tmp, page,
4894                                extent_offset, inline_size, max_size);
4895         if (ret) {
4896                 char *kaddr = kmap_atomic(page, KM_USER0);
4897                 unsigned long copy_size = min_t(u64,
4898                                   PAGE_CACHE_SIZE - pg_offset,
4899                                   max_size - extent_offset);
4900                 memset(kaddr + pg_offset, 0, copy_size);
4901                 kunmap_atomic(kaddr, KM_USER0);
4902         }
4903         kfree(tmp);
4904         return 0;
4905 }
4906
4907 /*
4908  * a bit scary, this does extent mapping from logical file offset to the disk.
4909  * the ugly parts come from merging extents from the disk with the in-ram
4910  * representation.  This gets more complex because of the data=ordered code,
4911  * where the in-ram extents might be locked pending data=ordered completion.
4912  *
4913  * This also copies inline extents directly into the page.
4914  */
4915
4916 struct extent_map *btrfs_get_extent(struct inode *inode, struct page *page,
4917                                     size_t pg_offset, u64 start, u64 len,
4918                                     int create)
4919 {
4920         int ret;
4921         int err = 0;
4922         u64 bytenr;
4923         u64 extent_start = 0;
4924         u64 extent_end = 0;
4925         u64 objectid = btrfs_ino(inode);
4926         u32 found_type;
4927         struct btrfs_path *path = NULL;
4928         struct btrfs_root *root = BTRFS_I(inode)->root;
4929         struct btrfs_file_extent_item *item;
4930         struct extent_buffer *leaf;
4931         struct btrfs_key found_key;
4932         struct extent_map *em = NULL;
4933         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
4934         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
4935         struct btrfs_trans_handle *trans = NULL;
4936         int compress_type;
4937
4938 again:
4939         read_lock(&em_tree->lock);
4940         em = lookup_extent_mapping(em_tree, start, len);
4941         if (em)
4942                 em->bdev = root->fs_info->fs_devices->latest_bdev;
4943         read_unlock(&em_tree->lock);
4944
4945         if (em) {
4946                 if (em->start > start || em->start + em->len <= start)
4947                         free_extent_map(em);
4948                 else if (em->block_start == EXTENT_MAP_INLINE && page)
4949                         free_extent_map(em);
4950                 else
4951                         goto out;
4952         }
4953         em = alloc_extent_map();
4954         if (!em) {
4955                 err = -ENOMEM;
4956                 goto out;
4957         }
4958         em->bdev = root->fs_info->fs_devices->latest_bdev;
4959         em->start = EXTENT_MAP_HOLE;
4960         em->orig_start = EXTENT_MAP_HOLE;
4961         em->len = (u64)-1;
4962         em->block_len = (u64)-1;
4963
4964         if (!path) {
4965                 path = btrfs_alloc_path();
4966                 if (!path) {
4967                         err = -ENOMEM;
4968                         goto out;
4969                 }
4970                 /*
4971                  * Chances are we'll be called again, so go ahead and do
4972                  * readahead
4973                  */
4974                 path->reada = 1;
4975         }
4976
4977         ret = btrfs_lookup_file_extent(trans, root, path,
4978                                        objectid, start, trans != NULL);
4979         if (ret < 0) {
4980                 err = ret;
4981                 goto out;
4982         }
4983
4984         if (ret != 0) {
4985                 if (path->slots[0] == 0)
4986                         goto not_found;
4987                 path->slots[0]--;
4988         }
4989
4990         leaf = path->nodes[0];
4991         item = btrfs_item_ptr(leaf, path->slots[0],
4992                               struct btrfs_file_extent_item);
4993         /* are we inside the extent that was found? */
4994         btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
4995         found_type = btrfs_key_type(&found_key);
4996         if (found_key.objectid != objectid ||
4997             found_type != BTRFS_EXTENT_DATA_KEY) {
4998                 goto not_found;
4999         }
5000
5001         found_type = btrfs_file_extent_type(leaf, item);
5002         extent_start = found_key.offset;
5003         compress_type = btrfs_file_extent_compression(leaf, item);
5004         if (found_type == BTRFS_FILE_EXTENT_REG ||
5005             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5006                 extent_end = extent_start +
5007                        btrfs_file_extent_num_bytes(leaf, item);
5008         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5009                 size_t size;
5010                 size = btrfs_file_extent_inline_len(leaf, item);
5011                 extent_end = (extent_start + size + root->sectorsize - 1) &
5012                         ~((u64)root->sectorsize - 1);
5013         }
5014
5015         if (start >= extent_end) {
5016                 path->slots[0]++;
5017                 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
5018                         ret = btrfs_next_leaf(root, path);
5019                         if (ret < 0) {
5020                                 err = ret;
5021                                 goto out;
5022                         }
5023                         if (ret > 0)
5024                                 goto not_found;
5025                         leaf = path->nodes[0];
5026                 }
5027                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
5028                 if (found_key.objectid != objectid ||
5029                     found_key.type != BTRFS_EXTENT_DATA_KEY)
5030                         goto not_found;
5031                 if (start + len <= found_key.offset)
5032                         goto not_found;
5033                 em->start = start;
5034                 em->len = found_key.offset - start;
5035                 goto not_found_em;
5036         }
5037
5038         if (found_type == BTRFS_FILE_EXTENT_REG ||
5039             found_type == BTRFS_FILE_EXTENT_PREALLOC) {
5040                 em->start = extent_start;
5041                 em->len = extent_end - extent_start;
5042                 em->orig_start = extent_start -
5043                                  btrfs_file_extent_offset(leaf, item);
5044                 bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
5045                 if (bytenr == 0) {
5046                         em->block_start = EXTENT_MAP_HOLE;
5047                         goto insert;
5048                 }
5049                 if (compress_type != BTRFS_COMPRESS_NONE) {
5050                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5051                         em->compress_type = compress_type;
5052                         em->block_start = bytenr;
5053                         em->block_len = btrfs_file_extent_disk_num_bytes(leaf,
5054                                                                          item);
5055                 } else {
5056                         bytenr += btrfs_file_extent_offset(leaf, item);
5057                         em->block_start = bytenr;
5058                         em->block_len = em->len;
5059                         if (found_type == BTRFS_FILE_EXTENT_PREALLOC)
5060                                 set_bit(EXTENT_FLAG_PREALLOC, &em->flags);
5061                 }
5062                 goto insert;
5063         } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
5064                 unsigned long ptr;
5065                 char *map;
5066                 size_t size;
5067                 size_t extent_offset;
5068                 size_t copy_size;
5069
5070                 em->block_start = EXTENT_MAP_INLINE;
5071                 if (!page || create) {
5072                         em->start = extent_start;
5073                         em->len = extent_end - extent_start;
5074                         goto out;
5075                 }
5076
5077                 size = btrfs_file_extent_inline_len(leaf, item);
5078                 extent_offset = page_offset(page) + pg_offset - extent_start;
5079                 copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
5080                                 size - extent_offset);
5081                 em->start = extent_start + extent_offset;
5082                 em->len = (copy_size + root->sectorsize - 1) &
5083                         ~((u64)root->sectorsize - 1);
5084                 em->orig_start = EXTENT_MAP_INLINE;
5085                 if (compress_type) {
5086                         set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
5087                         em->compress_type = compress_type;
5088                 }
5089                 ptr = btrfs_file_extent_inline_start(item) + extent_offset;
5090                 if (create == 0 && !PageUptodate(page)) {
5091                         if (btrfs_file_extent_compression(leaf, item) !=
5092                             BTRFS_COMPRESS_NONE) {
5093                                 ret = uncompress_inline(path, inode, page,
5094                                                         pg_offset,
5095                                                         extent_offset, item);
5096                                 BUG_ON(ret);
5097                         } else {
5098                                 map = kmap(page);
5099                                 read_extent_buffer(leaf, map + pg_offset, ptr,
5100                                                    copy_size);
5101                                 if (pg_offset + copy_size < PAGE_CACHE_SIZE) {
5102                                         memset(map + pg_offset + copy_size, 0,
5103                                                PAGE_CACHE_SIZE - pg_offset -
5104                                                copy_size);
5105                                 }
5106                                 kunmap(page);
5107                         }
5108                         flush_dcache_page(page);
5109                 } else if (create && PageUptodate(page)) {
5110                         WARN_ON(1);
5111                         if (!trans) {
5112                                 kunmap(page);
5113                                 free_extent_map(em);
5114                                 em = NULL;
5115
5116                                 btrfs_release_path(path);
5117                                 trans = btrfs_join_transaction(root);
5118
5119                                 if (IS_ERR(trans))
5120                                         return ERR_CAST(trans);
5121                                 goto again;
5122                         }
5123                         map = kmap(page);
5124                         write_extent_buffer(leaf, map + pg_offset, ptr,
5125                                             copy_size);
5126                         kunmap(page);
5127                         btrfs_mark_buffer_dirty(leaf);
5128                 }
5129                 set_extent_uptodate(io_tree, em->start,
5130                                     extent_map_end(em) - 1, NULL, GFP_NOFS);
5131                 goto insert;
5132         } else {
5133                 printk(KERN_ERR "btrfs unknown found_type %d\n", found_type);
5134                 WARN_ON(1);
5135         }
5136 not_found:
5137         em->start = start;
5138         em->len = len;
5139 not_found_em:
5140         em->block_start = EXTENT_MAP_HOLE;
5141         set_bit(EXTENT_FLAG_VACANCY, &em->flags);
5142 insert:
5143         btrfs_release_path(path);
5144         if (em->start > start || extent_map_end(em) <= start) {
5145                 printk(KERN_ERR "Btrfs: bad extent! em: [%llu %llu] passed "
5146                        "[%llu %llu]\n", (unsigned long long)em->start,
5147                        (unsigned long long)em->len,
5148                        (unsigned long long)start,
5149                        (unsigned long long)len);
5150                 err = -EIO;
5151                 goto out;
5152         }
5153
5154         err = 0;
5155         write_lock(&em_tree->lock);
5156         ret = add_extent_mapping(em_tree, em);
5157         /* it is possible that someone inserted the extent into the tree
5158          * while we had the lock dropped.  It is also possible that
5159          * an overlapping map exists in the tree
5160          */
5161         if (ret == -EEXIST) {
5162                 struct extent_map *existing;
5163
5164                 ret = 0;
5165
5166                 existing = lookup_extent_mapping(em_tree, start, len);
5167                 if (existing && (existing->start > start ||
5168                     existing->start + existing->len <= start)) {
5169                         free_extent_map(existing);
5170                         existing = NULL;
5171                 }
5172                 if (!existing) {
5173                         existing = lookup_extent_mapping(em_tree, em->start,
5174                                                          em->len);
5175                         if (existing) {
5176                                 err = merge_extent_mapping(em_tree, existing,
5177                                                            em, start,
5178                                                            root->sectorsize);
5179                                 free_extent_map(existing);
5180                                 if (err) {
5181                                         free_extent_map(em);
5182                                         em = NULL;
5183                                 }
5184                         } else {
5185                                 err = -EIO;
5186                                 free_extent_map(em);
5187                                 em = NULL;
5188                         }
5189                 } else {
5190                         free_extent_map(em);
5191                         em = existing;
5192                         err = 0;
5193                 }
5194         }
5195         write_unlock(&em_tree->lock);
5196 out:
5197
5198         trace_btrfs_get_extent(root, em);
5199
5200         if (path)
5201                 btrfs_free_path(path);
5202         if (trans) {
5203                 ret = btrfs_end_transaction(trans, root);
5204                 if (!err)
5205                         err = ret;
5206         }
5207         if (err) {
5208                 free_extent_map(em);
5209                 return ERR_PTR(err);
5210         }
5211         return em;
5212 }
5213
5214 struct extent_map *btrfs_get_extent_fiemap(struct inode *inode, struct page *page,
5215                                            size_t pg_offset, u64 start, u64 len,
5216                                            int create)
5217 {
5218         struct extent_map *em;
5219         struct extent_map *hole_em = NULL;
5220         u64 range_start = start;
5221         u64 end;
5222         u64 found;
5223         u64 found_end;
5224         int err = 0;
5225
5226         em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
5227         if (IS_ERR(em))
5228                 return em;
5229         if (em) {
5230                 /*
5231                  * if our em maps to a hole, there might
5232                  * actually be delalloc bytes behind it
5233                  */
5234                 if (em->block_start != EXTENT_MAP_HOLE)
5235                         return em;
5236                 else
5237                         hole_em = em;
5238         }
5239
5240         /* check to see if we've wrapped (len == -1 or similar) */
5241         end = start + len;
5242         if (end < start)
5243                 end = (u64)-1;
5244         else
5245                 end -= 1;
5246
5247         em = NULL;
5248
5249         /* ok, we didn't find anything, lets look for delalloc */
5250         found = count_range_bits(&BTRFS_I(inode)->io_tree, &range_start,
5251                                  end, len, EXTENT_DELALLOC, 1);
5252         found_end = range_start + found;
5253         if (found_end < range_start)
5254                 found_end = (u64)-1;
5255
5256         /*
5257          * we didn't find anything useful, return
5258          * the original results from get_extent()
5259          */
5260         if (range_start > end || found_end <= start) {
5261                 em = hole_em;
5262                 hole_em = NULL;
5263                 goto out;
5264         }
5265
5266         /* adjust the range_start to make sure it doesn't
5267          * go backwards from the start they passed in
5268          */
5269         range_start = max(start,range_start);
5270         found = found_end - range_start;
5271
5272         if (found > 0) {
5273                 u64 hole_start = start;
5274                 u64 hole_len = len;
5275
5276                 em = alloc_extent_map();
5277                 if (!em) {
5278                         err = -ENOMEM;
5279                         goto out;
5280                 }
5281                 /*
5282                  * when btrfs_get_extent can't find anything it
5283                  * returns one huge hole
5284                  *
5285                  * make sure what it found really fits our range, and
5286                  * adjust to make sure it is based on the start from
5287                  * the caller
5288                  */
5289                 if (hole_em) {
5290                         u64 calc_end = extent_map_end(hole_em);
5291
5292                         if (calc_end <= start || (hole_em->start > end)) {
5293                                 free_extent_map(hole_em);
5294                                 hole_em = NULL;
5295                         } else {
5296                                 hole_start = max(hole_em->start, start);
5297                                 hole_len = calc_end - hole_start;
5298                         }
5299                 }
5300                 em->bdev = NULL;
5301                 if (hole_em && range_start > hole_start) {
5302                         /* our hole starts before our delalloc, so we
5303                          * have to return just the parts of the hole
5304                          * that go until  the delalloc starts
5305                          */
5306                         em->len = min(hole_len,
5307                                       range_start - hole_start);
5308                         em->start = hole_start;
5309                         em->orig_start = hole_start;
5310                         /*
5311                          * don't adjust block start at all,
5312                          * it is fixed at EXTENT_MAP_HOLE
5313                          */
5314                         em->block_start = hole_em->block_start;
5315                         em->block_len = hole_len;
5316                 } else {
5317                         em->start = range_start;
5318                         em->len = found;
5319                         em->orig_start = range_start;
5320                         em->block_start = EXTENT_MAP_DELALLOC;
5321                         em->block_len = found;
5322                 }
5323         } else if (hole_em) {
5324                 return hole_em;
5325         }
5326 out:
5327
5328         free_extent_map(hole_em);
5329         if (err) {
5330                 free_extent_map(em);
5331                 return ERR_PTR(err);
5332         }
5333         return em;
5334 }
5335
5336 static struct extent_map *btrfs_new_extent_direct(struct inode *inode,
5337                                                   struct extent_map *em,
5338                                                   u64 start, u64 len)
5339 {
5340         struct btrfs_root *root = BTRFS_I(inode)->root;
5341         struct btrfs_trans_handle *trans;
5342         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
5343         struct btrfs_key ins;
5344         u64 alloc_hint;
5345         int ret;
5346         bool insert = false;
5347
5348         /*
5349          * Ok if the extent map we looked up is a hole and is for the exact
5350          * range we want, there is no reason to allocate a new one, however if
5351          * it is not right then we need to free this one and drop the cache for
5352          * our range.
5353          */
5354         if (em->block_start != EXTENT_MAP_HOLE || em->start != start ||
5355             em->len != len) {
5356                 free_extent_map(em);
5357                 em = NULL;
5358                 insert = true;
5359                 btrfs_drop_extent_cache(inode, start, start + len - 1, 0);
5360         }
5361
5362         trans = btrfs_join_transaction(root);
5363         if (IS_ERR(trans))
5364                 return ERR_CAST(trans);
5365
5366         if (start <= BTRFS_I(inode)->disk_i_size && len < 64 * 1024)
5367                 btrfs_add_inode_defrag(trans, inode);
5368
5369         trans->block_rsv = &root->fs_info->delalloc_block_rsv;
5370
5371         alloc_hint = get_extent_allocation_hint(inode, start, len);
5372         ret = btrfs_reserve_extent(trans, root, len, root->sectorsize, 0,
5373                                    alloc_hint, (u64)-1, &ins, 1);
5374         if (ret) {
5375                 em = ERR_PTR(ret);
5376                 goto out;
5377         }
5378
5379         if (!em) {
5380                 em = alloc_extent_map();
5381                 if (!em) {
5382                         em = ERR_PTR(-ENOMEM);
5383                         goto out;
5384                 }
5385         }
5386
5387         em->start = start;
5388         em->orig_start = em->start;
5389         em->len = ins.offset;
5390
5391         em->block_start = ins.objectid;
5392         em->block_len = ins.offset;
5393         em->bdev = root->fs_info->fs_devices->latest_bdev;
5394
5395         /*
5396          * We need to do this because if we're using the original em we searched
5397          * for, we could have EXTENT_FLAG_VACANCY set, and we don't want that.
5398          */
5399         em->flags = 0;
5400         set_bit(EXTENT_FLAG_PINNED, &em->flags);
5401
5402         while (insert) {
5403                 write_lock(&em_tree->lock);
5404                 ret = add_extent_mapping(em_tree, em);
5405                 write_unlock(&em_tree->lock);
5406                 if (ret != -EEXIST)
5407                         break;
5408                 btrfs_drop_extent_cache(inode, start, start + em->len - 1, 0);
5409         }
5410
5411         ret = btrfs_add_ordered_extent_dio(inode, start, ins.objectid,
5412                                            ins.offset, ins.offset, 0);
5413         if (ret) {
5414                 btrfs_free_reserved_extent(root, ins.objectid, ins.offset);
5415                 em = ERR_PTR(ret);
5416         }
5417 out:
5418         btrfs_end_transaction(trans, root);
5419         return em;
5420 }
5421
5422 /*
5423  * returns 1 when the nocow is safe, < 1 on error, 0 if the
5424  * block must be cow'd
5425  */
5426 static noinline int can_nocow_odirect(struct btrfs_trans_handle *trans,
5427                                       struct inode *inode, u64 offset, u64 len)
5428 {
5429         struct btrfs_path *path;
5430         int ret;
5431         struct extent_buffer *leaf;
5432         struct btrfs_root *root = BTRFS_I(inode)->root;
5433         struct btrfs_file_extent_item *fi;
5434         struct btrfs_key key;
5435         u64 disk_bytenr;
5436         u64 backref_offset;
5437         u64 extent_end;
5438         u64 num_bytes;
5439         int slot;
5440         int found_type;
5441
5442         path = btrfs_alloc_path();
5443         if (!path)
5444                 return -ENOMEM;
5445
5446         ret = btrfs_lookup_file_extent(trans, root, path, btrfs_ino(inode),
5447                                        offset, 0);
5448         if (ret < 0)
5449                 goto out;
5450
5451         slot = path->slots[0];
5452         if (ret == 1) {
5453                 if (slot == 0) {
5454                         /* can't find the item, must cow */
5455                         ret = 0;
5456                         goto out;
5457                 }
5458                 slot--;
5459         }
5460         ret = 0;
5461         leaf = path->nodes[0];
5462         btrfs_item_key_to_cpu(leaf, &key, slot);
5463         if (key.objectid != btrfs_ino(inode) ||
5464             key.type != BTRFS_EXTENT_DATA_KEY) {
5465                 /* not our file or wrong item type, must cow */
5466                 goto out;
5467         }
5468
5469         if (key.offset > offset) {
5470                 /* Wrong offset, must cow */
5471                 goto out;
5472         }
5473
5474         fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
5475         found_type = btrfs_file_extent_type(leaf, fi);
5476         if (found_type != BTRFS_FILE_EXTENT_REG &&
5477             found_type != BTRFS_FILE_EXTENT_PREALLOC) {
5478                 /* not a regular extent, must cow */
5479                 goto out;
5480         }
5481         disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
5482         backref_offset = btrfs_file_extent_offset(leaf, fi);
5483
5484         extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
5485         if (extent_end < offset + len) {
5486                 /* extent doesn't include our full range, must cow */
5487                 goto out;
5488         }
5489
5490         if (btrfs_extent_readonly(root, disk_bytenr))
5491                 goto out;
5492
5493         /*
5494          * look for other files referencing this extent, if we
5495          * find any we must cow
5496          */
5497         if (btrfs_cross_ref_exist(trans, root, btrfs_ino(inode),
5498                                   key.offset - backref_offset, disk_bytenr))
5499                 goto out;
5500
5501         /*
5502          * adjust disk_bytenr and num_bytes to cover just the bytes
5503          * in this extent we are about to write.  If there
5504          * are any csums in that range we have to cow in order
5505          * to keep the csums correct
5506          */
5507         disk_bytenr += backref_offset;
5508         disk_bytenr += offset - key.offset;
5509         num_bytes = min(offset + len, extent_end) - offset;
5510         if (csum_exist_in_range(root, disk_bytenr, num_bytes))
5511                                 goto out;
5512         /*
5513          * all of the above have passed, it is safe to overwrite this extent
5514          * without cow
5515          */
5516         ret = 1;
5517 out:
5518         btrfs_free_path(path);
5519         return ret;
5520 }
5521
5522 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
5523                                    struct buffer_head *bh_result, int create)
5524 {
5525         struct extent_map *em;
5526         struct btrfs_root *root = BTRFS_I(inode)->root;
5527         u64 start = iblock << inode->i_blkbits;
5528         u64 len = bh_result->b_size;
5529         struct btrfs_trans_handle *trans;
5530
5531         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
5532         if (IS_ERR(em))
5533                 return PTR_ERR(em);
5534
5535         /*
5536          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
5537          * io.  INLINE is special, and we could probably kludge it in here, but
5538          * it's still buffered so for safety lets just fall back to the generic
5539          * buffered path.
5540          *
5541          * For COMPRESSED we _have_ to read the entire extent in so we can
5542          * decompress it, so there will be buffering required no matter what we
5543          * do, so go ahead and fallback to buffered.
5544          *
5545          * We return -ENOTBLK because thats what makes DIO go ahead and go back
5546          * to buffered IO.  Don't blame me, this is the price we pay for using
5547          * the generic code.
5548          */
5549         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
5550             em->block_start == EXTENT_MAP_INLINE) {
5551                 free_extent_map(em);
5552                 return -ENOTBLK;
5553         }
5554
5555         /* Just a good old fashioned hole, return */
5556         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
5557                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
5558                 free_extent_map(em);
5559                 /* DIO will do one hole at a time, so just unlock a sector */
5560                 unlock_extent(&BTRFS_I(inode)->io_tree, start,
5561                               start + root->sectorsize - 1, GFP_NOFS);
5562                 return 0;
5563         }
5564
5565         /*
5566          * We don't allocate a new extent in the following cases
5567          *
5568          * 1) The inode is marked as NODATACOW.  In this case we'll just use the
5569          * existing extent.
5570          * 2) The extent is marked as PREALLOC.  We're good to go here and can
5571          * just use the extent.
5572          *
5573          */
5574         if (!create) {
5575                 len = em->len - (start - em->start);
5576                 goto map;
5577         }
5578
5579         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
5580             ((BTRFS_I(inode)->flags & BTRFS_INODE_NODATACOW) &&
5581              em->block_start != EXTENT_MAP_HOLE)) {
5582                 int type;
5583                 int ret;
5584                 u64 block_start;
5585
5586                 if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
5587                         type = BTRFS_ORDERED_PREALLOC;
5588                 else
5589                         type = BTRFS_ORDERED_NOCOW;
5590                 len = min(len, em->len - (start - em->start));
5591                 block_start = em->block_start + (start - em->start);
5592
5593                 /*
5594                  * we're not going to log anything, but we do need
5595                  * to make sure the current transaction stays open
5596                  * while we look for nocow cross refs
5597                  */
5598                 trans = btrfs_join_transaction(root);
5599                 if (IS_ERR(trans))
5600                         goto must_cow;
5601
5602                 if (can_nocow_odirect(trans, inode, start, len) == 1) {
5603                         ret = btrfs_add_ordered_extent_dio(inode, start,
5604                                            block_start, len, len, type);
5605                         btrfs_end_transaction(trans, root);
5606                         if (ret) {
5607                                 free_extent_map(em);
5608                                 return ret;
5609                         }
5610                         goto unlock;
5611                 }
5612                 btrfs_end_transaction(trans, root);
5613         }
5614 must_cow:
5615         /*
5616          * this will cow the extent, reset the len in case we changed
5617          * it above
5618          */
5619         len = bh_result->b_size;
5620         em = btrfs_new_extent_direct(inode, em, start, len);
5621         if (IS_ERR(em))
5622                 return PTR_ERR(em);
5623         len = min(len, em->len - (start - em->start));
5624 unlock:
5625         clear_extent_bit(&BTRFS_I(inode)->io_tree, start, start + len - 1,
5626                           EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DIRTY, 1,
5627                           0, NULL, GFP_NOFS);
5628 map:
5629         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
5630                 inode->i_blkbits;
5631         bh_result->b_size = len;
5632         bh_result->b_bdev = em->bdev;
5633         set_buffer_mapped(bh_result);
5634         if (create && !test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
5635                 set_buffer_new(bh_result);