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TOMOYO Linux Cross Reference
Linux/fs/btrfs/disk-io.c

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  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/fs.h>
 20 #include <linux/blkdev.h>
 21 #include <linux/scatterlist.h>
 22 #include <linux/swap.h>
 23 #include <linux/radix-tree.h>
 24 #include <linux/writeback.h>
 25 #include <linux/buffer_head.h>
 26 #include <linux/workqueue.h>
 27 #include <linux/kthread.h>
 28 #include <linux/freezer.h>
 29 #include <linux/slab.h>
 30 #include <linux/migrate.h>
 31 #include <linux/ratelimit.h>
 32 #include <linux/uuid.h>
 33 #include <linux/semaphore.h>
 34 #include <asm/unaligned.h>
 35 #include "ctree.h"
 36 #include "disk-io.h"
 37 #include "hash.h"
 38 #include "transaction.h"
 39 #include "btrfs_inode.h"
 40 #include "volumes.h"
 41 #include "print-tree.h"
 42 #include "locking.h"
 43 #include "tree-log.h"
 44 #include "free-space-cache.h"
 45 #include "inode-map.h"
 46 #include "check-integrity.h"
 47 #include "rcu-string.h"
 48 #include "dev-replace.h"
 49 #include "raid56.h"
 50 #include "sysfs.h"
 51 #include "qgroup.h"
 52 
 53 #ifdef CONFIG_X86
 54 #include <asm/cpufeature.h>
 55 #endif
 56 
 57 static const struct extent_io_ops btree_extent_io_ops;
 58 static void end_workqueue_fn(struct btrfs_work *work);
 59 static void free_fs_root(struct btrfs_root *root);
 60 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
 61                                     int read_only);
 62 static void btrfs_destroy_ordered_extents(struct btrfs_root *root);
 63 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
 64                                       struct btrfs_root *root);
 65 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root);
 66 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
 67                                         struct extent_io_tree *dirty_pages,
 68                                         int mark);
 69 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
 70                                        struct extent_io_tree *pinned_extents);
 71 static int btrfs_cleanup_transaction(struct btrfs_root *root);
 72 static void btrfs_error_commit_super(struct btrfs_root *root);
 73 
 74 /*
 75  * btrfs_end_io_wq structs are used to do processing in task context when an IO
 76  * is complete.  This is used during reads to verify checksums, and it is used
 77  * by writes to insert metadata for new file extents after IO is complete.
 78  */
 79 struct btrfs_end_io_wq {
 80         struct bio *bio;
 81         bio_end_io_t *end_io;
 82         void *private;
 83         struct btrfs_fs_info *info;
 84         int error;
 85         enum btrfs_wq_endio_type metadata;
 86         struct list_head list;
 87         struct btrfs_work work;
 88 };
 89 
 90 static struct kmem_cache *btrfs_end_io_wq_cache;
 91 
 92 int __init btrfs_end_io_wq_init(void)
 93 {
 94         btrfs_end_io_wq_cache = kmem_cache_create("btrfs_end_io_wq",
 95                                         sizeof(struct btrfs_end_io_wq),
 96                                         0,
 97                                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
 98                                         NULL);
 99         if (!btrfs_end_io_wq_cache)
100                 return -ENOMEM;
101         return 0;
102 }
103 
104 void btrfs_end_io_wq_exit(void)
105 {
106         if (btrfs_end_io_wq_cache)
107                 kmem_cache_destroy(btrfs_end_io_wq_cache);
108 }
109 
110 /*
111  * async submit bios are used to offload expensive checksumming
112  * onto the worker threads.  They checksum file and metadata bios
113  * just before they are sent down the IO stack.
114  */
115 struct async_submit_bio {
116         struct inode *inode;
117         struct bio *bio;
118         struct list_head list;
119         extent_submit_bio_hook_t *submit_bio_start;
120         extent_submit_bio_hook_t *submit_bio_done;
121         int rw;
122         int mirror_num;
123         unsigned long bio_flags;
124         /*
125          * bio_offset is optional, can be used if the pages in the bio
126          * can't tell us where in the file the bio should go
127          */
128         u64 bio_offset;
129         struct btrfs_work work;
130         int error;
131 };
132 
133 /*
134  * Lockdep class keys for extent_buffer->lock's in this root.  For a given
135  * eb, the lockdep key is determined by the btrfs_root it belongs to and
136  * the level the eb occupies in the tree.
137  *
138  * Different roots are used for different purposes and may nest inside each
139  * other and they require separate keysets.  As lockdep keys should be
140  * static, assign keysets according to the purpose of the root as indicated
141  * by btrfs_root->objectid.  This ensures that all special purpose roots
142  * have separate keysets.
143  *
144  * Lock-nesting across peer nodes is always done with the immediate parent
145  * node locked thus preventing deadlock.  As lockdep doesn't know this, use
146  * subclass to avoid triggering lockdep warning in such cases.
147  *
148  * The key is set by the readpage_end_io_hook after the buffer has passed
149  * csum validation but before the pages are unlocked.  It is also set by
150  * btrfs_init_new_buffer on freshly allocated blocks.
151  *
152  * We also add a check to make sure the highest level of the tree is the
153  * same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this code
154  * needs update as well.
155  */
156 #ifdef CONFIG_DEBUG_LOCK_ALLOC
157 # if BTRFS_MAX_LEVEL != 8
158 #  error
159 # endif
160 
161 static struct btrfs_lockdep_keyset {
162         u64                     id;             /* root objectid */
163         const char              *name_stem;     /* lock name stem */
164         char                    names[BTRFS_MAX_LEVEL + 1][20];
165         struct lock_class_key   keys[BTRFS_MAX_LEVEL + 1];
166 } btrfs_lockdep_keysets[] = {
167         { .id = BTRFS_ROOT_TREE_OBJECTID,       .name_stem = "root"     },
168         { .id = BTRFS_EXTENT_TREE_OBJECTID,     .name_stem = "extent"   },
169         { .id = BTRFS_CHUNK_TREE_OBJECTID,      .name_stem = "chunk"    },
170         { .id = BTRFS_DEV_TREE_OBJECTID,        .name_stem = "dev"      },
171         { .id = BTRFS_FS_TREE_OBJECTID,         .name_stem = "fs"       },
172         { .id = BTRFS_CSUM_TREE_OBJECTID,       .name_stem = "csum"     },
173         { .id = BTRFS_QUOTA_TREE_OBJECTID,      .name_stem = "quota"    },
174         { .id = BTRFS_TREE_LOG_OBJECTID,        .name_stem = "log"      },
175         { .id = BTRFS_TREE_RELOC_OBJECTID,      .name_stem = "treloc"   },
176         { .id = BTRFS_DATA_RELOC_TREE_OBJECTID, .name_stem = "dreloc"   },
177         { .id = BTRFS_UUID_TREE_OBJECTID,       .name_stem = "uuid"     },
178         { .id = 0,                              .name_stem = "tree"     },
179 };
180 
181 void __init btrfs_init_lockdep(void)
182 {
183         int i, j;
184 
185         /* initialize lockdep class names */
186         for (i = 0; i < ARRAY_SIZE(btrfs_lockdep_keysets); i++) {
187                 struct btrfs_lockdep_keyset *ks = &btrfs_lockdep_keysets[i];
188 
189                 for (j = 0; j < ARRAY_SIZE(ks->names); j++)
190                         snprintf(ks->names[j], sizeof(ks->names[j]),
191                                  "btrfs-%s-%02d", ks->name_stem, j);
192         }
193 }
194 
195 void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb,
196                                     int level)
197 {
198         struct btrfs_lockdep_keyset *ks;
199 
200         BUG_ON(level >= ARRAY_SIZE(ks->keys));
201 
202         /* find the matching keyset, id 0 is the default entry */
203         for (ks = btrfs_lockdep_keysets; ks->id; ks++)
204                 if (ks->id == objectid)
205                         break;
206 
207         lockdep_set_class_and_name(&eb->lock,
208                                    &ks->keys[level], ks->names[level]);
209 }
210 
211 #endif
212 
213 /*
214  * extents on the btree inode are pretty simple, there's one extent
215  * that covers the entire device
216  */
217 static struct extent_map *btree_get_extent(struct inode *inode,
218                 struct page *page, size_t pg_offset, u64 start, u64 len,
219                 int create)
220 {
221         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
222         struct extent_map *em;
223         int ret;
224 
225         read_lock(&em_tree->lock);
226         em = lookup_extent_mapping(em_tree, start, len);
227         if (em) {
228                 em->bdev =
229                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
230                 read_unlock(&em_tree->lock);
231                 goto out;
232         }
233         read_unlock(&em_tree->lock);
234 
235         em = alloc_extent_map();
236         if (!em) {
237                 em = ERR_PTR(-ENOMEM);
238                 goto out;
239         }
240         em->start = 0;
241         em->len = (u64)-1;
242         em->block_len = (u64)-1;
243         em->block_start = 0;
244         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
245 
246         write_lock(&em_tree->lock);
247         ret = add_extent_mapping(em_tree, em, 0);
248         if (ret == -EEXIST) {
249                 free_extent_map(em);
250                 em = lookup_extent_mapping(em_tree, start, len);
251                 if (!em)
252                         em = ERR_PTR(-EIO);
253         } else if (ret) {
254                 free_extent_map(em);
255                 em = ERR_PTR(ret);
256         }
257         write_unlock(&em_tree->lock);
258 
259 out:
260         return em;
261 }
262 
263 u32 btrfs_csum_data(char *data, u32 seed, size_t len)
264 {
265         return btrfs_crc32c(seed, data, len);
266 }
267 
268 void btrfs_csum_final(u32 crc, char *result)
269 {
270         put_unaligned_le32(~crc, result);
271 }
272 
273 /*
274  * compute the csum for a btree block, and either verify it or write it
275  * into the csum field of the block.
276  */
277 static int csum_tree_block(struct btrfs_fs_info *fs_info,
278                            struct extent_buffer *buf,
279                            int verify)
280 {
281         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
282         char *result = NULL;
283         unsigned long len;
284         unsigned long cur_len;
285         unsigned long offset = BTRFS_CSUM_SIZE;
286         char *kaddr;
287         unsigned long map_start;
288         unsigned long map_len;
289         int err;
290         u32 crc = ~(u32)0;
291         unsigned long inline_result;
292 
293         len = buf->len - offset;
294         while (len > 0) {
295                 err = map_private_extent_buffer(buf, offset, 32,
296                                         &kaddr, &map_start, &map_len);
297                 if (err)
298                         return 1;
299                 cur_len = min(len, map_len - (offset - map_start));
300                 crc = btrfs_csum_data(kaddr + offset - map_start,
301                                       crc, cur_len);
302                 len -= cur_len;
303                 offset += cur_len;
304         }
305         if (csum_size > sizeof(inline_result)) {
306                 result = kzalloc(csum_size, GFP_NOFS);
307                 if (!result)
308                         return 1;
309         } else {
310                 result = (char *)&inline_result;
311         }
312 
313         btrfs_csum_final(crc, result);
314 
315         if (verify) {
316                 if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
317                         u32 val;
318                         u32 found = 0;
319                         memcpy(&found, result, csum_size);
320 
321                         read_extent_buffer(buf, &val, 0, csum_size);
322                         printk_ratelimited(KERN_WARNING
323                                 "BTRFS: %s checksum verify failed on %llu wanted %X found %X "
324                                 "level %d\n",
325                                 fs_info->sb->s_id, buf->start,
326                                 val, found, btrfs_header_level(buf));
327                         if (result != (char *)&inline_result)
328                                 kfree(result);
329                         return 1;
330                 }
331         } else {
332                 write_extent_buffer(buf, result, 0, csum_size);
333         }
334         if (result != (char *)&inline_result)
335                 kfree(result);
336         return 0;
337 }
338 
339 /*
340  * we can't consider a given block up to date unless the transid of the
341  * block matches the transid in the parent node's pointer.  This is how we
342  * detect blocks that either didn't get written at all or got written
343  * in the wrong place.
344  */
345 static int verify_parent_transid(struct extent_io_tree *io_tree,
346                                  struct extent_buffer *eb, u64 parent_transid,
347                                  int atomic)
348 {
349         struct extent_state *cached_state = NULL;
350         int ret;
351         bool need_lock = (current->journal_info == BTRFS_SEND_TRANS_STUB);
352 
353         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
354                 return 0;
355 
356         if (atomic)
357                 return -EAGAIN;
358 
359         if (need_lock) {
360                 btrfs_tree_read_lock(eb);
361                 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
362         }
363 
364         lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
365                          0, &cached_state);
366         if (extent_buffer_uptodate(eb) &&
367             btrfs_header_generation(eb) == parent_transid) {
368                 ret = 0;
369                 goto out;
370         }
371         printk_ratelimited(KERN_ERR
372             "BTRFS (device %s): parent transid verify failed on %llu wanted %llu found %llu\n",
373                         eb->fs_info->sb->s_id, eb->start,
374                         parent_transid, btrfs_header_generation(eb));
375         ret = 1;
376 
377         /*
378          * Things reading via commit roots that don't have normal protection,
379          * like send, can have a really old block in cache that may point at a
380          * block that has been free'd and re-allocated.  So don't clear uptodate
381          * if we find an eb that is under IO (dirty/writeback) because we could
382          * end up reading in the stale data and then writing it back out and
383          * making everybody very sad.
384          */
385         if (!extent_buffer_under_io(eb))
386                 clear_extent_buffer_uptodate(eb);
387 out:
388         unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
389                              &cached_state, GFP_NOFS);
390         if (need_lock)
391                 btrfs_tree_read_unlock_blocking(eb);
392         return ret;
393 }
394 
395 /*
396  * Return 0 if the superblock checksum type matches the checksum value of that
397  * algorithm. Pass the raw disk superblock data.
398  */
399 static int btrfs_check_super_csum(char *raw_disk_sb)
400 {
401         struct btrfs_super_block *disk_sb =
402                 (struct btrfs_super_block *)raw_disk_sb;
403         u16 csum_type = btrfs_super_csum_type(disk_sb);
404         int ret = 0;
405 
406         if (csum_type == BTRFS_CSUM_TYPE_CRC32) {
407                 u32 crc = ~(u32)0;
408                 const int csum_size = sizeof(crc);
409                 char result[csum_size];
410 
411                 /*
412                  * The super_block structure does not span the whole
413                  * BTRFS_SUPER_INFO_SIZE range, we expect that the unused space
414                  * is filled with zeros and is included in the checkum.
415                  */
416                 crc = btrfs_csum_data(raw_disk_sb + BTRFS_CSUM_SIZE,
417                                 crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
418                 btrfs_csum_final(crc, result);
419 
420                 if (memcmp(raw_disk_sb, result, csum_size))
421                         ret = 1;
422         }
423 
424         if (csum_type >= ARRAY_SIZE(btrfs_csum_sizes)) {
425                 printk(KERN_ERR "BTRFS: unsupported checksum algorithm %u\n",
426                                 csum_type);
427                 ret = 1;
428         }
429 
430         return ret;
431 }
432 
433 /*
434  * helper to read a given tree block, doing retries as required when
435  * the checksums don't match and we have alternate mirrors to try.
436  */
437 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
438                                           struct extent_buffer *eb,
439                                           u64 start, u64 parent_transid)
440 {
441         struct extent_io_tree *io_tree;
442         int failed = 0;
443         int ret;
444         int num_copies = 0;
445         int mirror_num = 0;
446         int failed_mirror = 0;
447 
448         clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
449         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
450         while (1) {
451                 ret = read_extent_buffer_pages(io_tree, eb, start,
452                                                WAIT_COMPLETE,
453                                                btree_get_extent, mirror_num);
454                 if (!ret) {
455                         if (!verify_parent_transid(io_tree, eb,
456                                                    parent_transid, 0))
457                                 break;
458                         else
459                                 ret = -EIO;
460                 }
461 
462                 /*
463                  * This buffer's crc is fine, but its contents are corrupted, so
464                  * there is no reason to read the other copies, they won't be
465                  * any less wrong.
466                  */
467                 if (test_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags))
468                         break;
469 
470                 num_copies = btrfs_num_copies(root->fs_info,
471                                               eb->start, eb->len);
472                 if (num_copies == 1)
473                         break;
474 
475                 if (!failed_mirror) {
476                         failed = 1;
477                         failed_mirror = eb->read_mirror;
478                 }
479 
480                 mirror_num++;
481                 if (mirror_num == failed_mirror)
482                         mirror_num++;
483 
484                 if (mirror_num > num_copies)
485                         break;
486         }
487 
488         if (failed && !ret && failed_mirror)
489                 repair_eb_io_failure(root, eb, failed_mirror);
490 
491         return ret;
492 }
493 
494 /*
495  * checksum a dirty tree block before IO.  This has extra checks to make sure
496  * we only fill in the checksum field in the first page of a multi-page block
497  */
498 
499 static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct page *page)
500 {
501         u64 start = page_offset(page);
502         u64 found_start;
503         struct extent_buffer *eb;
504 
505         eb = (struct extent_buffer *)page->private;
506         if (page != eb->pages[0])
507                 return 0;
508         found_start = btrfs_header_bytenr(eb);
509         if (WARN_ON(found_start != start || !PageUptodate(page)))
510                 return 0;
511         csum_tree_block(fs_info, eb, 0);
512         return 0;
513 }
514 
515 static int check_tree_block_fsid(struct btrfs_fs_info *fs_info,
516                                  struct extent_buffer *eb)
517 {
518         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
519         u8 fsid[BTRFS_UUID_SIZE];
520         int ret = 1;
521 
522         read_extent_buffer(eb, fsid, btrfs_header_fsid(), BTRFS_FSID_SIZE);
523         while (fs_devices) {
524                 if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
525                         ret = 0;
526                         break;
527                 }
528                 fs_devices = fs_devices->seed;
529         }
530         return ret;
531 }
532 
533 #define CORRUPT(reason, eb, root, slot)                         \
534         btrfs_crit(root->fs_info, "corrupt leaf, %s: block=%llu,"       \
535                    "root=%llu, slot=%d", reason,                        \
536                btrfs_header_bytenr(eb), root->objectid, slot)
537 
538 static noinline int check_leaf(struct btrfs_root *root,
539                                struct extent_buffer *leaf)
540 {
541         struct btrfs_key key;
542         struct btrfs_key leaf_key;
543         u32 nritems = btrfs_header_nritems(leaf);
544         int slot;
545 
546         if (nritems == 0)
547                 return 0;
548 
549         /* Check the 0 item */
550         if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=
551             BTRFS_LEAF_DATA_SIZE(root)) {
552                 CORRUPT("invalid item offset size pair", leaf, root, 0);
553                 return -EIO;
554         }
555 
556         /*
557          * Check to make sure each items keys are in the correct order and their
558          * offsets make sense.  We only have to loop through nritems-1 because
559          * we check the current slot against the next slot, which verifies the
560          * next slot's offset+size makes sense and that the current's slot
561          * offset is correct.
562          */
563         for (slot = 0; slot < nritems - 1; slot++) {
564                 btrfs_item_key_to_cpu(leaf, &leaf_key, slot);
565                 btrfs_item_key_to_cpu(leaf, &key, slot + 1);
566 
567                 /* Make sure the keys are in the right order */
568                 if (btrfs_comp_cpu_keys(&leaf_key, &key) >= 0) {
569                         CORRUPT("bad key order", leaf, root, slot);
570                         return -EIO;
571                 }
572 
573                 /*
574                  * Make sure the offset and ends are right, remember that the
575                  * item data starts at the end of the leaf and grows towards the
576                  * front.
577                  */
578                 if (btrfs_item_offset_nr(leaf, slot) !=
579                         btrfs_item_end_nr(leaf, slot + 1)) {
580                         CORRUPT("slot offset bad", leaf, root, slot);
581                         return -EIO;
582                 }
583 
584                 /*
585                  * Check to make sure that we don't point outside of the leaf,
586                  * just incase all the items are consistent to eachother, but
587                  * all point outside of the leaf.
588                  */
589                 if (btrfs_item_end_nr(leaf, slot) >
590                     BTRFS_LEAF_DATA_SIZE(root)) {
591                         CORRUPT("slot end outside of leaf", leaf, root, slot);
592                         return -EIO;
593                 }
594         }
595 
596         return 0;
597 }
598 
599 static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
600                                       u64 phy_offset, struct page *page,
601                                       u64 start, u64 end, int mirror)
602 {
603         u64 found_start;
604         int found_level;
605         struct extent_buffer *eb;
606         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
607         int ret = 0;
608         int reads_done;
609 
610         if (!page->private)
611                 goto out;
612 
613         eb = (struct extent_buffer *)page->private;
614 
615         /* the pending IO might have been the only thing that kept this buffer
616          * in memory.  Make sure we have a ref for all this other checks
617          */
618         extent_buffer_get(eb);
619 
620         reads_done = atomic_dec_and_test(&eb->io_pages);
621         if (!reads_done)
622                 goto err;
623 
624         eb->read_mirror = mirror;
625         if (test_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags)) {
626                 ret = -EIO;
627                 goto err;
628         }
629 
630         found_start = btrfs_header_bytenr(eb);
631         if (found_start != eb->start) {
632                 printk_ratelimited(KERN_ERR "BTRFS (device %s): bad tree block start "
633                                "%llu %llu\n",
634                                eb->fs_info->sb->s_id, found_start, eb->start);
635                 ret = -EIO;
636                 goto err;
637         }
638         if (check_tree_block_fsid(root->fs_info, eb)) {
639                 printk_ratelimited(KERN_ERR "BTRFS (device %s): bad fsid on block %llu\n",
640                                eb->fs_info->sb->s_id, eb->start);
641                 ret = -EIO;
642                 goto err;
643         }
644         found_level = btrfs_header_level(eb);
645         if (found_level >= BTRFS_MAX_LEVEL) {
646                 btrfs_err(root->fs_info, "bad tree block level %d",
647                            (int)btrfs_header_level(eb));
648                 ret = -EIO;
649                 goto err;
650         }
651 
652         btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb),
653                                        eb, found_level);
654 
655         ret = csum_tree_block(root->fs_info, eb, 1);
656         if (ret) {
657                 ret = -EIO;
658                 goto err;
659         }
660 
661         /*
662          * If this is a leaf block and it is corrupt, set the corrupt bit so
663          * that we don't try and read the other copies of this block, just
664          * return -EIO.
665          */
666         if (found_level == 0 && check_leaf(root, eb)) {
667                 set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
668                 ret = -EIO;
669         }
670 
671         if (!ret)
672                 set_extent_buffer_uptodate(eb);
673 err:
674         if (reads_done &&
675             test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
676                 btree_readahead_hook(root, eb, eb->start, ret);
677 
678         if (ret) {
679                 /*
680                  * our io error hook is going to dec the io pages
681                  * again, we have to make sure it has something
682                  * to decrement
683                  */
684                 atomic_inc(&eb->io_pages);
685                 clear_extent_buffer_uptodate(eb);
686         }
687         free_extent_buffer(eb);
688 out:
689         return ret;
690 }
691 
692 static int btree_io_failed_hook(struct page *page, int failed_mirror)
693 {
694         struct extent_buffer *eb;
695         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
696 
697         eb = (struct extent_buffer *)page->private;
698         set_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
699         eb->read_mirror = failed_mirror;
700         atomic_dec(&eb->io_pages);
701         if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
702                 btree_readahead_hook(root, eb, eb->start, -EIO);
703         return -EIO;    /* we fixed nothing */
704 }
705 
706 static void end_workqueue_bio(struct bio *bio)
707 {
708         struct btrfs_end_io_wq *end_io_wq = bio->bi_private;
709         struct btrfs_fs_info *fs_info;
710         struct btrfs_workqueue *wq;
711         btrfs_work_func_t func;
712 
713         fs_info = end_io_wq->info;
714         end_io_wq->error = bio->bi_error;
715 
716         if (bio->bi_rw & REQ_WRITE) {
717                 if (end_io_wq->metadata == BTRFS_WQ_ENDIO_METADATA) {
718                         wq = fs_info->endio_meta_write_workers;
719                         func = btrfs_endio_meta_write_helper;
720                 } else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_FREE_SPACE) {
721                         wq = fs_info->endio_freespace_worker;
722                         func = btrfs_freespace_write_helper;
723                 } else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56) {
724                         wq = fs_info->endio_raid56_workers;
725                         func = btrfs_endio_raid56_helper;
726                 } else {
727                         wq = fs_info->endio_write_workers;
728                         func = btrfs_endio_write_helper;
729                 }
730         } else {
731                 if (unlikely(end_io_wq->metadata ==
732                              BTRFS_WQ_ENDIO_DIO_REPAIR)) {
733                         wq = fs_info->endio_repair_workers;
734                         func = btrfs_endio_repair_helper;
735                 } else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56) {
736                         wq = fs_info->endio_raid56_workers;
737                         func = btrfs_endio_raid56_helper;
738                 } else if (end_io_wq->metadata) {
739                         wq = fs_info->endio_meta_workers;
740                         func = btrfs_endio_meta_helper;
741                 } else {
742                         wq = fs_info->endio_workers;
743                         func = btrfs_endio_helper;
744                 }
745         }
746 
747         btrfs_init_work(&end_io_wq->work, func, end_workqueue_fn, NULL, NULL);
748         btrfs_queue_work(wq, &end_io_wq->work);
749 }
750 
751 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
752                         enum btrfs_wq_endio_type metadata)
753 {
754         struct btrfs_end_io_wq *end_io_wq;
755 
756         end_io_wq = kmem_cache_alloc(btrfs_end_io_wq_cache, GFP_NOFS);
757         if (!end_io_wq)
758                 return -ENOMEM;
759 
760         end_io_wq->private = bio->bi_private;
761         end_io_wq->end_io = bio->bi_end_io;
762         end_io_wq->info = info;
763         end_io_wq->error = 0;
764         end_io_wq->bio = bio;
765         end_io_wq->metadata = metadata;
766 
767         bio->bi_private = end_io_wq;
768         bio->bi_end_io = end_workqueue_bio;
769         return 0;
770 }
771 
772 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
773 {
774         unsigned long limit = min_t(unsigned long,
775                                     info->thread_pool_size,
776                                     info->fs_devices->open_devices);
777         return 256 * limit;
778 }
779 
780 static void run_one_async_start(struct btrfs_work *work)
781 {
782         struct async_submit_bio *async;
783         int ret;
784 
785         async = container_of(work, struct  async_submit_bio, work);
786         ret = async->submit_bio_start(async->inode, async->rw, async->bio,
787                                       async->mirror_num, async->bio_flags,
788                                       async->bio_offset);
789         if (ret)
790                 async->error = ret;
791 }
792 
793 static void run_one_async_done(struct btrfs_work *work)
794 {
795         struct btrfs_fs_info *fs_info;
796         struct async_submit_bio *async;
797         int limit;
798 
799         async = container_of(work, struct  async_submit_bio, work);
800         fs_info = BTRFS_I(async->inode)->root->fs_info;
801 
802         limit = btrfs_async_submit_limit(fs_info);
803         limit = limit * 2 / 3;
804 
805         if (atomic_dec_return(&fs_info->nr_async_submits) < limit &&
806             waitqueue_active(&fs_info->async_submit_wait))
807                 wake_up(&fs_info->async_submit_wait);
808 
809         /* If an error occured we just want to clean up the bio and move on */
810         if (async->error) {
811                 async->bio->bi_error = async->error;
812                 bio_endio(async->bio);
813                 return;
814         }
815 
816         async->submit_bio_done(async->inode, async->rw, async->bio,
817                                async->mirror_num, async->bio_flags,
818                                async->bio_offset);
819 }
820 
821 static void run_one_async_free(struct btrfs_work *work)
822 {
823         struct async_submit_bio *async;
824 
825         async = container_of(work, struct  async_submit_bio, work);
826         kfree(async);
827 }
828 
829 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
830                         int rw, struct bio *bio, int mirror_num,
831                         unsigned long bio_flags,
832                         u64 bio_offset,
833                         extent_submit_bio_hook_t *submit_bio_start,
834                         extent_submit_bio_hook_t *submit_bio_done)
835 {
836         struct async_submit_bio *async;
837 
838         async = kmalloc(sizeof(*async), GFP_NOFS);
839         if (!async)
840                 return -ENOMEM;
841 
842         async->inode = inode;
843         async->rw = rw;
844         async->bio = bio;
845         async->mirror_num = mirror_num;
846         async->submit_bio_start = submit_bio_start;
847         async->submit_bio_done = submit_bio_done;
848 
849         btrfs_init_work(&async->work, btrfs_worker_helper, run_one_async_start,
850                         run_one_async_done, run_one_async_free);
851 
852         async->bio_flags = bio_flags;
853         async->bio_offset = bio_offset;
854 
855         async->error = 0;
856 
857         atomic_inc(&fs_info->nr_async_submits);
858 
859         if (rw & REQ_SYNC)
860                 btrfs_set_work_high_priority(&async->work);
861 
862         btrfs_queue_work(fs_info->workers, &async->work);
863 
864         while (atomic_read(&fs_info->async_submit_draining) &&
865               atomic_read(&fs_info->nr_async_submits)) {
866                 wait_event(fs_info->async_submit_wait,
867                            (atomic_read(&fs_info->nr_async_submits) == 0));
868         }
869 
870         return 0;
871 }
872 
873 static int btree_csum_one_bio(struct bio *bio)
874 {
875         struct bio_vec *bvec;
876         struct btrfs_root *root;
877         int i, ret = 0;
878 
879         bio_for_each_segment_all(bvec, bio, i) {
880                 root = BTRFS_I(bvec->bv_page->mapping->host)->root;
881                 ret = csum_dirty_buffer(root->fs_info, bvec->bv_page);
882                 if (ret)
883                         break;
884         }
885 
886         return ret;
887 }
888 
889 static int __btree_submit_bio_start(struct inode *inode, int rw,
890                                     struct bio *bio, int mirror_num,
891                                     unsigned long bio_flags,
892                                     u64 bio_offset)
893 {
894         /*
895          * when we're called for a write, we're already in the async
896          * submission context.  Just jump into btrfs_map_bio
897          */
898         return btree_csum_one_bio(bio);
899 }
900 
901 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
902                                  int mirror_num, unsigned long bio_flags,
903                                  u64 bio_offset)
904 {
905         int ret;
906 
907         /*
908          * when we're called for a write, we're already in the async
909          * submission context.  Just jump into btrfs_map_bio
910          */
911         ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
912         if (ret) {
913                 bio->bi_error = ret;
914                 bio_endio(bio);
915         }
916         return ret;
917 }
918 
919 static int check_async_write(struct inode *inode, unsigned long bio_flags)
920 {
921         if (bio_flags & EXTENT_BIO_TREE_LOG)
922                 return 0;
923 #ifdef CONFIG_X86
924         if (cpu_has_xmm4_2)
925                 return 0;
926 #endif
927         return 1;
928 }
929 
930 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
931                                  int mirror_num, unsigned long bio_flags,
932                                  u64 bio_offset)
933 {
934         int async = check_async_write(inode, bio_flags);
935         int ret;
936 
937         if (!(rw & REQ_WRITE)) {
938                 /*
939                  * called for a read, do the setup so that checksum validation
940                  * can happen in the async kernel threads
941                  */
942                 ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
943                                           bio, BTRFS_WQ_ENDIO_METADATA);
944                 if (ret)
945                         goto out_w_error;
946                 ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
947                                     mirror_num, 0);
948         } else if (!async) {
949                 ret = btree_csum_one_bio(bio);
950                 if (ret)
951                         goto out_w_error;
952                 ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
953                                     mirror_num, 0);
954         } else {
955                 /*
956                  * kthread helpers are used to submit writes so that
957                  * checksumming can happen in parallel across all CPUs
958                  */
959                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
960                                           inode, rw, bio, mirror_num, 0,
961                                           bio_offset,
962                                           __btree_submit_bio_start,
963                                           __btree_submit_bio_done);
964         }
965 
966         if (ret)
967                 goto out_w_error;
968         return 0;
969 
970 out_w_error:
971         bio->bi_error = ret;
972         bio_endio(bio);
973         return ret;
974 }
975 
976 #ifdef CONFIG_MIGRATION
977 static int btree_migratepage(struct address_space *mapping,
978                         struct page *newpage, struct page *page,
979                         enum migrate_mode mode)
980 {
981         /*
982          * we can't safely write a btree page from here,
983          * we haven't done the locking hook
984          */
985         if (PageDirty(page))
986                 return -EAGAIN;
987         /*
988          * Buffers may be managed in a filesystem specific way.
989          * We must have no buffers or drop them.
990          */
991         if (page_has_private(page) &&
992             !try_to_release_page(page, GFP_KERNEL))
993                 return -EAGAIN;
994         return migrate_page(mapping, newpage, page, mode);
995 }
996 #endif
997 
998 
999 static int btree_writepages(struct address_space *mapping,
1000                             struct writeback_control *wbc)
1001 {
1002         struct btrfs_fs_info *fs_info;
1003         int ret;
1004 
1005         if (wbc->sync_mode == WB_SYNC_NONE) {
1006 
1007                 if (wbc->for_kupdate)
1008                         return 0;
1009 
1010                 fs_info = BTRFS_I(mapping->host)->root->fs_info;
1011                 /* this is a bit racy, but that's ok */
1012                 ret = percpu_counter_compare(&fs_info->dirty_metadata_bytes,
1013                                              BTRFS_DIRTY_METADATA_THRESH);
1014                 if (ret < 0)
1015                         return 0;
1016         }
1017         return btree_write_cache_pages(mapping, wbc);
1018 }
1019 
1020 static int btree_readpage(struct file *file, struct page *page)
1021 {
1022         struct extent_io_tree *tree;
1023         tree = &BTRFS_I(page->mapping->host)->io_tree;
1024         return extent_read_full_page(tree, page, btree_get_extent, 0);
1025 }
1026 
1027 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
1028 {
1029         if (PageWriteback(page) || PageDirty(page))
1030                 return 0;
1031 
1032         return try_release_extent_buffer(page);
1033 }
1034 
1035 static void btree_invalidatepage(struct page *page, unsigned int offset,
1036                                  unsigned int length)
1037 {
1038         struct extent_io_tree *tree;
1039         tree = &BTRFS_I(page->mapping->host)->io_tree;
1040         extent_invalidatepage(tree, page, offset);
1041         btree_releasepage(page, GFP_NOFS);
1042         if (PagePrivate(page)) {
1043                 btrfs_warn(BTRFS_I(page->mapping->host)->root->fs_info,
1044                            "page private not zero on page %llu",
1045                            (unsigned long long)page_offset(page));
1046                 ClearPagePrivate(page);
1047                 set_page_private(page, 0);
1048                 page_cache_release(page);
1049         }
1050 }
1051 
1052 static int btree_set_page_dirty(struct page *page)
1053 {
1054 #ifdef DEBUG
1055         struct extent_buffer *eb;
1056 
1057         BUG_ON(!PagePrivate(page));
1058         eb = (struct extent_buffer *)page->private;
1059         BUG_ON(!eb);
1060         BUG_ON(!test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
1061         BUG_ON(!atomic_read(&eb->refs));
1062         btrfs_assert_tree_locked(eb);
1063 #endif
1064         return __set_page_dirty_nobuffers(page);
1065 }
1066 
1067 static const struct address_space_operations btree_aops = {
1068         .readpage       = btree_readpage,
1069         .writepages     = btree_writepages,
1070         .releasepage    = btree_releasepage,
1071         .invalidatepage = btree_invalidatepage,
1072 #ifdef CONFIG_MIGRATION
1073         .migratepage    = btree_migratepage,
1074 #endif
1075         .set_page_dirty = btree_set_page_dirty,
1076 };
1077 
1078 void readahead_tree_block(struct btrfs_root *root, u64 bytenr)
1079 {
1080         struct extent_buffer *buf = NULL;
1081         struct inode *btree_inode = root->fs_info->btree_inode;
1082 
1083         buf = btrfs_find_create_tree_block(root, bytenr);
1084         if (!buf)
1085                 return;
1086         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
1087                                  buf, 0, WAIT_NONE, btree_get_extent, 0);
1088         free_extent_buffer(buf);
1089 }
1090 
1091 int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr,
1092                          int mirror_num, struct extent_buffer **eb)
1093 {
1094         struct extent_buffer *buf = NULL;
1095         struct inode *btree_inode = root->fs_info->btree_inode;
1096         struct extent_io_tree *io_tree = &BTRFS_I(btree_inode)->io_tree;
1097         int ret;
1098 
1099         buf = btrfs_find_create_tree_block(root, bytenr);
1100         if (!buf)
1101                 return 0;
1102 
1103         set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
1104 
1105         ret = read_extent_buffer_pages(io_tree, buf, 0, WAIT_PAGE_LOCK,
1106                                        btree_get_extent, mirror_num);
1107         if (ret) {
1108                 free_extent_buffer(buf);
1109                 return ret;
1110         }
1111 
1112         if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags)) {
1113                 free_extent_buffer(buf);
1114                 return -EIO;
1115         } else if (extent_buffer_uptodate(buf)) {
1116                 *eb = buf;
1117         } else {
1118                 free_extent_buffer(buf);
1119         }
1120         return 0;
1121 }
1122 
1123 struct extent_buffer *btrfs_find_tree_block(struct btrfs_fs_info *fs_info,
1124                                             u64 bytenr)
1125 {
1126         return find_extent_buffer(fs_info, bytenr);
1127 }
1128 
1129 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
1130                                                  u64 bytenr)
1131 {
1132         if (btrfs_test_is_dummy_root(root))
1133                 return alloc_test_extent_buffer(root->fs_info, bytenr);
1134         return alloc_extent_buffer(root->fs_info, bytenr);
1135 }
1136 
1137 
1138 int btrfs_write_tree_block(struct extent_buffer *buf)
1139 {
1140         return filemap_fdatawrite_range(buf->pages[0]->mapping, buf->start,
1141                                         buf->start + buf->len - 1);
1142 }
1143 
1144 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
1145 {
1146         return filemap_fdatawait_range(buf->pages[0]->mapping,
1147                                        buf->start, buf->start + buf->len - 1);
1148 }
1149 
1150 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
1151                                       u64 parent_transid)
1152 {
1153         struct extent_buffer *buf = NULL;
1154         int ret;
1155 
1156         buf = btrfs_find_create_tree_block(root, bytenr);
1157         if (!buf)
1158                 return ERR_PTR(-ENOMEM);
1159 
1160         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
1161         if (ret) {
1162                 free_extent_buffer(buf);
1163                 return ERR_PTR(ret);
1164         }
1165         return buf;
1166 
1167 }
1168 
1169 void clean_tree_block(struct btrfs_trans_handle *trans,
1170                       struct btrfs_fs_info *fs_info,
1171                       struct extent_buffer *buf)
1172 {
1173         if (btrfs_header_generation(buf) ==
1174             fs_info->running_transaction->transid) {
1175                 btrfs_assert_tree_locked(buf);
1176 
1177                 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
1178                         __percpu_counter_add(&fs_info->dirty_metadata_bytes,
1179                                              -buf->len,
1180                                              fs_info->dirty_metadata_batch);
1181                         /* ugh, clear_extent_buffer_dirty needs to lock the page */
1182                         btrfs_set_lock_blocking(buf);
1183                         clear_extent_buffer_dirty(buf);
1184                 }
1185         }
1186 }
1187 
1188 static struct btrfs_subvolume_writers *btrfs_alloc_subvolume_writers(void)
1189 {
1190         struct btrfs_subvolume_writers *writers;
1191         int ret;
1192 
1193         writers = kmalloc(sizeof(*writers), GFP_NOFS);
1194         if (!writers)
1195                 return ERR_PTR(-ENOMEM);
1196 
1197         ret = percpu_counter_init(&writers->counter, 0, GFP_KERNEL);
1198         if (ret < 0) {
1199                 kfree(writers);
1200                 return ERR_PTR(ret);
1201         }
1202 
1203         init_waitqueue_head(&writers->wait);
1204         return writers;
1205 }
1206 
1207 static void
1208 btrfs_free_subvolume_writers(struct btrfs_subvolume_writers *writers)
1209 {
1210         percpu_counter_destroy(&writers->counter);
1211         kfree(writers);
1212 }
1213 
1214 static void __setup_root(u32 nodesize, u32 sectorsize, u32 stripesize,
1215                          struct btrfs_root *root, struct btrfs_fs_info *fs_info,
1216                          u64 objectid)
1217 {
1218         root->node = NULL;
1219         root->commit_root = NULL;
1220         root->sectorsize = sectorsize;
1221         root->nodesize = nodesize;
1222         root->stripesize = stripesize;
1223         root->state = 0;
1224         root->orphan_cleanup_state = 0;
1225 
1226         root->objectid = objectid;
1227         root->last_trans = 0;
1228         root->highest_objectid = 0;
1229         root->nr_delalloc_inodes = 0;
1230         root->nr_ordered_extents = 0;
1231         root->name = NULL;
1232         root->inode_tree = RB_ROOT;
1233         INIT_RADIX_TREE(&root->delayed_nodes_tree, GFP_ATOMIC);
1234         root->block_rsv = NULL;
1235         root->orphan_block_rsv = NULL;
1236 
1237         INIT_LIST_HEAD(&root->dirty_list);
1238         INIT_LIST_HEAD(&root->root_list);
1239         INIT_LIST_HEAD(&root->delalloc_inodes);
1240         INIT_LIST_HEAD(&root->delalloc_root);
1241         INIT_LIST_HEAD(&root->ordered_extents);
1242         INIT_LIST_HEAD(&root->ordered_root);
1243         INIT_LIST_HEAD(&root->logged_list[0]);
1244         INIT_LIST_HEAD(&root->logged_list[1]);
1245         spin_lock_init(&root->orphan_lock);
1246         spin_lock_init(&root->inode_lock);
1247         spin_lock_init(&root->delalloc_lock);
1248         spin_lock_init(&root->ordered_extent_lock);
1249         spin_lock_init(&root->accounting_lock);
1250         spin_lock_init(&root->log_extents_lock[0]);
1251         spin_lock_init(&root->log_extents_lock[1]);
1252         mutex_init(&root->objectid_mutex);
1253         mutex_init(&root->log_mutex);
1254         mutex_init(&root->ordered_extent_mutex);
1255         mutex_init(&root->delalloc_mutex);
1256         init_waitqueue_head(&root->log_writer_wait);
1257         init_waitqueue_head(&root->log_commit_wait[0]);
1258         init_waitqueue_head(&root->log_commit_wait[1]);
1259         INIT_LIST_HEAD(&root->log_ctxs[0]);
1260         INIT_LIST_HEAD(&root->log_ctxs[1]);
1261         atomic_set(&root->log_commit[0], 0);
1262         atomic_set(&root->log_commit[1], 0);
1263         atomic_set(&root->log_writers, 0);
1264         atomic_set(&root->log_batch, 0);
1265         atomic_set(&root->orphan_inodes, 0);
1266         atomic_set(&root->refs, 1);
1267         atomic_set(&root->will_be_snapshoted, 0);
1268         root->log_transid = 0;
1269         root->log_transid_committed = -1;
1270         root->last_log_commit = 0;
1271         if (fs_info)
1272                 extent_io_tree_init(&root->dirty_log_pages,
1273                                      fs_info->btree_inode->i_mapping);
1274 
1275         memset(&root->root_key, 0, sizeof(root->root_key));
1276         memset(&root->root_item, 0, sizeof(root->root_item));
1277         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
1278         if (fs_info)
1279                 root->defrag_trans_start = fs_info->generation;
1280         else
1281                 root->defrag_trans_start = 0;
1282         root->root_key.objectid = objectid;
1283         root->anon_dev = 0;
1284 
1285         spin_lock_init(&root->root_item_lock);
1286 }
1287 
1288 static struct btrfs_root *btrfs_alloc_root(struct btrfs_fs_info *fs_info)
1289 {
1290         struct btrfs_root *root = kzalloc(sizeof(*root), GFP_NOFS);
1291         if (root)
1292                 root->fs_info = fs_info;
1293         return root;
1294 }
1295 
1296 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
1297 /* Should only be used by the testing infrastructure */
1298 struct btrfs_root *btrfs_alloc_dummy_root(void)
1299 {
1300         struct btrfs_root *root;
1301 
1302         root = btrfs_alloc_root(NULL);
1303         if (!root)
1304                 return ERR_PTR(-ENOMEM);
1305         __setup_root(4096, 4096, 4096, root, NULL, 1);
1306         set_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state);
1307         root->alloc_bytenr = 0;
1308 
1309         return root;
1310 }
1311 #endif
1312 
1313 struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
1314                                      struct btrfs_fs_info *fs_info,
1315                                      u64 objectid)
1316 {
1317         struct extent_buffer *leaf;
1318         struct btrfs_root *tree_root = fs_info->tree_root;
1319         struct btrfs_root *root;
1320         struct btrfs_key key;
1321         int ret = 0;
1322         uuid_le uuid;
1323 
1324         root = btrfs_alloc_root(fs_info);
1325         if (!root)
1326                 return ERR_PTR(-ENOMEM);
1327 
1328         __setup_root(tree_root->nodesize, tree_root->sectorsize,
1329                 tree_root->stripesize, root, fs_info, objectid);
1330         root->root_key.objectid = objectid;
1331         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1332         root->root_key.offset = 0;
1333 
1334         leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0);
1335         if (IS_ERR(leaf)) {
1336                 ret = PTR_ERR(leaf);
1337                 leaf = NULL;
1338                 goto fail;
1339         }
1340 
1341         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1342         btrfs_set_header_bytenr(leaf, leaf->start);
1343         btrfs_set_header_generation(leaf, trans->transid);
1344         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1345         btrfs_set_header_owner(leaf, objectid);
1346         root->node = leaf;
1347 
1348         write_extent_buffer(leaf, fs_info->fsid, btrfs_header_fsid(),
1349                             BTRFS_FSID_SIZE);
1350         write_extent_buffer(leaf, fs_info->chunk_tree_uuid,
1351                             btrfs_header_chunk_tree_uuid(leaf),
1352                             BTRFS_UUID_SIZE);
1353         btrfs_mark_buffer_dirty(leaf);
1354 
1355         root->commit_root = btrfs_root_node(root);
1356         set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
1357 
1358         root->root_item.flags = 0;
1359         root->root_item.byte_limit = 0;
1360         btrfs_set_root_bytenr(&root->root_item, leaf->start);
1361         btrfs_set_root_generation(&root->root_item, trans->transid);
1362         btrfs_set_root_level(&root->root_item, 0);
1363         btrfs_set_root_refs(&root->root_item, 1);
1364         btrfs_set_root_used(&root->root_item, leaf->len);
1365         btrfs_set_root_last_snapshot(&root->root_item, 0);
1366         btrfs_set_root_dirid(&root->root_item, 0);
1367         uuid_le_gen(&uuid);
1368         memcpy(root->root_item.uuid, uuid.b, BTRFS_UUID_SIZE);
1369         root->root_item.drop_level = 0;
1370 
1371         key.objectid = objectid;
1372         key.type = BTRFS_ROOT_ITEM_KEY;
1373         key.offset = 0;
1374         ret = btrfs_insert_root(trans, tree_root, &key, &root->root_item);
1375         if (ret)
1376                 goto fail;
1377 
1378         btrfs_tree_unlock(leaf);
1379 
1380         return root;
1381 
1382 fail:
1383         if (leaf) {
1384                 btrfs_tree_unlock(leaf);
1385                 free_extent_buffer(root->commit_root);
1386                 free_extent_buffer(leaf);
1387         }
1388         kfree(root);
1389 
1390         return ERR_PTR(ret);
1391 }
1392 
1393 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1394                                          struct btrfs_fs_info *fs_info)
1395 {
1396         struct btrfs_root *root;
1397         struct btrfs_root *tree_root = fs_info->tree_root;
1398         struct extent_buffer *leaf;
1399 
1400         root = btrfs_alloc_root(fs_info);
1401         if (!root)
1402                 return ERR_PTR(-ENOMEM);
1403 
1404         __setup_root(tree_root->nodesize, tree_root->sectorsize,
1405                      tree_root->stripesize, root, fs_info,
1406                      BTRFS_TREE_LOG_OBJECTID);
1407 
1408         root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1409         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1410         root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1411 
1412         /*
1413          * DON'T set REF_COWS for log trees
1414          *
1415          * log trees do not get reference counted because they go away
1416          * before a real commit is actually done.  They do store pointers
1417          * to file data extents, and those reference counts still get
1418          * updated (along with back refs to the log tree).
1419          */
1420 
1421         leaf = btrfs_alloc_tree_block(trans, root, 0, BTRFS_TREE_LOG_OBJECTID,
1422                         NULL, 0, 0, 0);
1423         if (IS_ERR(leaf)) {
1424                 kfree(root);
1425                 return ERR_CAST(leaf);
1426         }
1427 
1428         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1429         btrfs_set_header_bytenr(leaf, leaf->start);
1430         btrfs_set_header_generation(leaf, trans->transid);
1431         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1432         btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
1433         root->node = leaf;
1434 
1435         write_extent_buffer(root->node, root->fs_info->fsid,
1436                             btrfs_header_fsid(), BTRFS_FSID_SIZE);
1437         btrfs_mark_buffer_dirty(root->node);
1438         btrfs_tree_unlock(root->node);
1439         return root;
1440 }
1441 
1442 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1443                              struct btrfs_fs_info *fs_info)
1444 {
1445         struct btrfs_root *log_root;
1446 
1447         log_root = alloc_log_tree(trans, fs_info);
1448         if (IS_ERR(log_root))
1449                 return PTR_ERR(log_root);
1450         WARN_ON(fs_info->log_root_tree);
1451         fs_info->log_root_tree = log_root;
1452         return 0;
1453 }
1454 
1455 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1456                        struct btrfs_root *root)
1457 {
1458         struct btrfs_root *log_root;
1459         struct btrfs_inode_item *inode_item;
1460 
1461         log_root = alloc_log_tree(trans, root->fs_info);
1462         if (IS_ERR(log_root))
1463                 return PTR_ERR(log_root);
1464 
1465         log_root->last_trans = trans->transid;
1466         log_root->root_key.offset = root->root_key.objectid;
1467 
1468         inode_item = &log_root->root_item.inode;
1469         btrfs_set_stack_inode_generation(inode_item, 1);
1470         btrfs_set_stack_inode_size(inode_item, 3);
1471         btrfs_set_stack_inode_nlink(inode_item, 1);
1472         btrfs_set_stack_inode_nbytes(inode_item, root->nodesize);
1473         btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
1474 
1475         btrfs_set_root_node(&log_root->root_item, log_root->node);
1476 
1477         WARN_ON(root->log_root);
1478         root->log_root = log_root;
1479         root->log_transid = 0;
1480         root->log_transid_committed = -1;
1481         root->last_log_commit = 0;
1482         return 0;
1483 }
1484 
1485 static struct btrfs_root *btrfs_read_tree_root(struct btrfs_root *tree_root,
1486                                                struct btrfs_key *key)
1487 {
1488         struct btrfs_root *root;
1489         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1490         struct btrfs_path *path;
1491         u64 generation;
1492         int ret;
1493 
1494         path = btrfs_alloc_path();
1495         if (!path)
1496                 return ERR_PTR(-ENOMEM);
1497 
1498         root = btrfs_alloc_root(fs_info);
1499         if (!root) {
1500                 ret = -ENOMEM;
1501                 goto alloc_fail;
1502         }
1503 
1504         __setup_root(tree_root->nodesize, tree_root->sectorsize,
1505                 tree_root->stripesize, root, fs_info, key->objectid);
1506 
1507         ret = btrfs_find_root(tree_root, key, path,
1508                               &root->root_item, &root->root_key);
1509         if (ret) {
1510                 if (ret > 0)
1511                         ret = -ENOENT;
1512                 goto find_fail;
1513         }
1514 
1515         generation = btrfs_root_generation(&root->root_item);
1516         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1517                                      generation);
1518         if (IS_ERR(root->node)) {
1519                 ret = PTR_ERR(root->node);
1520                 goto find_fail;
1521         } else if (!btrfs_buffer_uptodate(root->node, generation, 0)) {
1522                 ret = -EIO;
1523                 free_extent_buffer(root->node);
1524                 goto find_fail;
1525         }
1526         root->commit_root = btrfs_root_node(root);
1527 out:
1528         btrfs_free_path(path);
1529         return root;
1530 
1531 find_fail:
1532         kfree(root);
1533 alloc_fail:
1534         root = ERR_PTR(ret);
1535         goto out;
1536 }
1537 
1538 struct btrfs_root *btrfs_read_fs_root(struct btrfs_root *tree_root,
1539                                       struct btrfs_key *location)
1540 {
1541         struct btrfs_root *root;
1542 
1543         root = btrfs_read_tree_root(tree_root, location);
1544         if (IS_ERR(root))
1545                 return root;
1546 
1547         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
1548                 set_bit(BTRFS_ROOT_REF_COWS, &root->state);
1549                 btrfs_check_and_init_root_item(&root->root_item);
1550         }
1551 
1552         return root;
1553 }
1554 
1555 int btrfs_init_fs_root(struct btrfs_root *root)
1556 {
1557         int ret;
1558         struct btrfs_subvolume_writers *writers;
1559 
1560         root->free_ino_ctl = kzalloc(sizeof(*root->free_ino_ctl), GFP_NOFS);
1561         root->free_ino_pinned = kzalloc(sizeof(*root->free_ino_pinned),
1562                                         GFP_NOFS);
1563         if (!root->free_ino_pinned || !root->free_ino_ctl) {
1564                 ret = -ENOMEM;
1565                 goto fail;
1566         }
1567 
1568         writers = btrfs_alloc_subvolume_writers();
1569         if (IS_ERR(writers)) {
1570                 ret = PTR_ERR(writers);
1571                 goto fail;
1572         }
1573         root->subv_writers = writers;
1574 
1575         btrfs_init_free_ino_ctl(root);
1576         spin_lock_init(&root->ino_cache_lock);
1577         init_waitqueue_head(&root->ino_cache_wait);
1578 
1579         ret = get_anon_bdev(&root->anon_dev);
1580         if (ret)
1581                 goto free_writers;
1582         return 0;
1583 
1584 free_writers:
1585         btrfs_free_subvolume_writers(root->subv_writers);
1586 fail:
1587         kfree(root->free_ino_ctl);
1588         kfree(root->free_ino_pinned);
1589         return ret;
1590 }
1591 
1592 static struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
1593                                                u64 root_id)
1594 {
1595         struct btrfs_root *root;
1596 
1597         spin_lock(&fs_info->fs_roots_radix_lock);
1598         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1599                                  (unsigned long)root_id);
1600         spin_unlock(&fs_info->fs_roots_radix_lock);
1601         return root;
1602 }
1603 
1604 int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
1605                          struct btrfs_root *root)
1606 {
1607         int ret;
1608 
1609         ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
1610         if (ret)
1611                 return ret;
1612 
1613         spin_lock(&fs_info->fs_roots_radix_lock);
1614         ret = radix_tree_insert(&fs_info->fs_roots_radix,
1615                                 (unsigned long)root->root_key.objectid,
1616                                 root);
1617         if (ret == 0)
1618                 set_bit(BTRFS_ROOT_IN_RADIX, &root->state);
1619         spin_unlock(&fs_info->fs_roots_radix_lock);
1620         radix_tree_preload_end();
1621 
1622         return ret;
1623 }
1624 
1625 struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
1626                                      struct btrfs_key *location,
1627                                      bool check_ref)
1628 {
1629         struct btrfs_root *root;
1630         struct btrfs_path *path;
1631         struct btrfs_key key;
1632         int ret;
1633 
1634         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1635                 return fs_info->tree_root;
1636         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1637                 return fs_info->extent_root;
1638         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1639                 return fs_info->chunk_root;
1640         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1641                 return fs_info->dev_root;
1642         if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
1643                 return fs_info->csum_root;
1644         if (location->objectid == BTRFS_QUOTA_TREE_OBJECTID)
1645                 return fs_info->quota_root ? fs_info->quota_root :
1646                                              ERR_PTR(-ENOENT);
1647         if (location->objectid == BTRFS_UUID_TREE_OBJECTID)
1648                 return fs_info->uuid_root ? fs_info->uuid_root :
1649                                             ERR_PTR(-ENOENT);
1650 again:
1651         root = btrfs_lookup_fs_root(fs_info, location->objectid);
1652         if (root) {
1653                 if (check_ref && btrfs_root_refs(&root->root_item) == 0)
1654                         return ERR_PTR(-ENOENT);
1655                 return root;
1656         }
1657 
1658         root = btrfs_read_fs_root(fs_info->tree_root, location);
1659         if (IS_ERR(root))
1660                 return root;
1661 
1662         if (check_ref && btrfs_root_refs(&root->root_item) == 0) {
1663                 ret = -ENOENT;
1664                 goto fail;
1665         }
1666 
1667         ret = btrfs_init_fs_root(root);
1668         if (ret)
1669                 goto fail;
1670 
1671         path = btrfs_alloc_path();
1672         if (!path) {
1673                 ret = -ENOMEM;
1674                 goto fail;
1675         }
1676         key.objectid = BTRFS_ORPHAN_OBJECTID;
1677         key.type = BTRFS_ORPHAN_ITEM_KEY;
1678         key.offset = location->objectid;
1679 
1680         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
1681         btrfs_free_path(path);
1682         if (ret < 0)
1683                 goto fail;
1684         if (ret == 0)
1685                 set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
1686 
1687         ret = btrfs_insert_fs_root(fs_info, root);
1688         if (ret) {
1689                 if (ret == -EEXIST) {
1690                         free_fs_root(root);
1691                         goto again;
1692                 }
1693                 goto fail;
1694         }
1695         return root;
1696 fail:
1697         free_fs_root(root);
1698         return ERR_PTR(ret);
1699 }
1700 
1701 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1702 {
1703         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1704         int ret = 0;
1705         struct btrfs_device *device;
1706         struct backing_dev_info *bdi;
1707 
1708         rcu_read_lock();
1709         list_for_each_entry_rcu(device, &info->fs_devices->devices, dev_list) {
1710                 if (!device->bdev)
1711                         continue;
1712                 bdi = blk_get_backing_dev_info(device->bdev);
1713                 if (bdi_congested(bdi, bdi_bits)) {
1714                         ret = 1;
1715                         break;
1716                 }
1717         }
1718         rcu_read_unlock();
1719         return ret;
1720 }
1721 
1722 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1723 {
1724         int err;
1725 
1726         err = bdi_setup_and_register(bdi, "btrfs");
1727         if (err)
1728                 return err;
1729 
1730         bdi->ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_CACHE_SIZE;
1731         bdi->congested_fn       = btrfs_congested_fn;
1732         bdi->congested_data     = info;
1733         bdi->capabilities |= BDI_CAP_CGROUP_WRITEBACK;
1734         return 0;
1735 }
1736 
1737 /*
1738  * called by the kthread helper functions to finally call the bio end_io
1739  * functions.  This is where read checksum verification actually happens
1740  */
1741 static void end_workqueue_fn(struct btrfs_work *work)
1742 {
1743         struct bio *bio;
1744         struct btrfs_end_io_wq *end_io_wq;
1745 
1746         end_io_wq = container_of(work, struct btrfs_end_io_wq, work);
1747         bio = end_io_wq->bio;
1748 
1749         bio->bi_error = end_io_wq->error;
1750         bio->bi_private = end_io_wq->private;
1751         bio->bi_end_io = end_io_wq->end_io;
1752         kmem_cache_free(btrfs_end_io_wq_cache, end_io_wq);
1753         bio_endio(bio);
1754 }
1755 
1756 static int cleaner_kthread(void *arg)
1757 {
1758         struct btrfs_root *root = arg;
1759         int again;
1760         struct btrfs_trans_handle *trans;
1761 
1762         do {
1763                 again = 0;
1764 
1765                 /* Make the cleaner go to sleep early. */
1766                 if (btrfs_need_cleaner_sleep(root))
1767                         goto sleep;
1768 
1769                 if (!mutex_trylock(&root->fs_info->cleaner_mutex))
1770                         goto sleep;
1771 
1772                 /*
1773                  * Avoid the problem that we change the status of the fs
1774                  * during the above check and trylock.
1775                  */
1776                 if (btrfs_need_cleaner_sleep(root)) {
1777                         mutex_unlock(&root->fs_info->cleaner_mutex);
1778                         goto sleep;
1779                 }
1780 
1781                 btrfs_run_delayed_iputs(root);
1782                 again = btrfs_clean_one_deleted_snapshot(root);
1783                 mutex_unlock(&root->fs_info->cleaner_mutex);
1784 
1785                 /*
1786                  * The defragger has dealt with the R/O remount and umount,
1787                  * needn't do anything special here.
1788                  */
1789                 btrfs_run_defrag_inodes(root->fs_info);
1790 
1791                 /*
1792                  * Acquires fs_info->delete_unused_bgs_mutex to avoid racing
1793                  * with relocation (btrfs_relocate_chunk) and relocation
1794                  * acquires fs_info->cleaner_mutex (btrfs_relocate_block_group)
1795                  * after acquiring fs_info->delete_unused_bgs_mutex. So we
1796                  * can't hold, nor need to, fs_info->cleaner_mutex when deleting
1797                  * unused block groups.
1798                  */
1799                 btrfs_delete_unused_bgs(root->fs_info);
1800 sleep:
1801                 if (!try_to_freeze() && !again) {
1802                         set_current_state(TASK_INTERRUPTIBLE);
1803                         if (!kthread_should_stop())
1804                                 schedule();
1805                         __set_current_state(TASK_RUNNING);
1806                 }
1807         } while (!kthread_should_stop());
1808 
1809         /*
1810          * Transaction kthread is stopped before us and wakes us up.
1811          * However we might have started a new transaction and COWed some
1812          * tree blocks when deleting unused block groups for example. So
1813          * make sure we commit the transaction we started to have a clean
1814          * shutdown when evicting the btree inode - if it has dirty pages
1815          * when we do the final iput() on it, eviction will trigger a
1816          * writeback for it which will fail with null pointer dereferences
1817          * since work queues and other resources were already released and
1818          * destroyed by the time the iput/eviction/writeback is made.
1819          */
1820         trans = btrfs_attach_transaction(root);
1821         if (IS_ERR(trans)) {
1822                 if (PTR_ERR(trans) != -ENOENT)
1823                         btrfs_err(root->fs_info,
1824                                   "cleaner transaction attach returned %ld",
1825                                   PTR_ERR(trans));
1826         } else {
1827                 int ret;
1828 
1829                 ret = btrfs_commit_transaction(trans, root);
1830                 if (ret)
1831                         btrfs_err(root->fs_info,
1832                                   "cleaner open transaction commit returned %d",
1833                                   ret);
1834         }
1835 
1836         return 0;
1837 }
1838 
1839 static int transaction_kthread(void *arg)
1840 {
1841         struct btrfs_root *root = arg;
1842         struct btrfs_trans_handle *trans;
1843         struct btrfs_transaction *cur;
1844         u64 transid;
1845         unsigned long now;
1846         unsigned long delay;
1847         bool cannot_commit;
1848 
1849         do {
1850                 cannot_commit = false;
1851                 delay = HZ * root->fs_info->commit_interval;
1852                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1853 
1854                 spin_lock(&root->fs_info->trans_lock);
1855                 cur = root->fs_info->running_transaction;
1856                 if (!cur) {
1857                         spin_unlock(&root->fs_info->trans_lock);
1858                         goto sleep;
1859                 }
1860 
1861                 now = get_seconds();
1862                 if (cur->state < TRANS_STATE_BLOCKED &&
1863                     (now < cur->start_time ||
1864                      now - cur->start_time < root->fs_info->commit_interval)) {
1865                         spin_unlock(&root->fs_info->trans_lock);
1866                         delay = HZ * 5;
1867                         goto sleep;
1868                 }
1869                 transid = cur->transid;
1870                 spin_unlock(&root->fs_info->trans_lock);
1871 
1872                 /* If the file system is aborted, this will always fail. */
1873                 trans = btrfs_attach_transaction(root);
1874                 if (IS_ERR(trans)) {
1875                         if (PTR_ERR(trans) != -ENOENT)
1876                                 cannot_commit = true;
1877                         goto sleep;
1878                 }
1879                 if (transid == trans->transid) {
1880                         btrfs_commit_transaction(trans, root);
1881                 } else {
1882                         btrfs_end_transaction(trans, root);
1883                 }
1884 sleep:
1885                 wake_up_process(root->fs_info->cleaner_kthread);
1886                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1887 
1888                 if (unlikely(test_bit(BTRFS_FS_STATE_ERROR,
1889                                       &root->fs_info->fs_state)))
1890                         btrfs_cleanup_transaction(root);
1891                 if (!try_to_freeze()) {
1892                         set_current_state(TASK_INTERRUPTIBLE);
1893                         if (!kthread_should_stop() &&
1894                             (!btrfs_transaction_blocked(root->fs_info) ||
1895                              cannot_commit))
1896                                 schedule_timeout(delay);
1897                         __set_current_state(TASK_RUNNING);
1898                 }
1899         } while (!kthread_should_stop());
1900         return 0;
1901 }
1902 
1903 /*
1904  * this will find the highest generation in the array of
1905  * root backups.  The index of the highest array is returned,
1906  * or -1 if we can't find anything.
1907  *
1908  * We check to make sure the array is valid by comparing the
1909  * generation of the latest  root in the array with the generation
1910  * in the super block.  If they don't match we pitch it.
1911  */
1912 static int find_newest_super_backup(struct btrfs_fs_info *info, u64 newest_gen)
1913 {
1914         u64 cur;
1915         int newest_index = -1;
1916         struct btrfs_root_backup *root_backup;
1917         int i;
1918 
1919         for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; i++) {
1920                 root_backup = info->super_copy->super_roots + i;
1921                 cur = btrfs_backup_tree_root_gen(root_backup);
1922                 if (cur == newest_gen)
1923                         newest_index = i;
1924         }
1925 
1926         /* check to see if we actually wrapped around */
1927         if (newest_index == BTRFS_NUM_BACKUP_ROOTS - 1) {
1928                 root_backup = info->super_copy->super_roots;
1929                 cur = btrfs_backup_tree_root_gen(root_backup);
1930                 if (cur == newest_gen)
1931                         newest_index = 0;
1932         }
1933         return newest_index;
1934 }
1935 
1936 
1937 /*
1938  * find the oldest backup so we know where to store new entries
1939  * in the backup array.  This will set the backup_root_index
1940  * field in the fs_info struct
1941  */
1942 static void find_oldest_super_backup(struct btrfs_fs_info *info,
1943                                      u64 newest_gen)
1944 {
1945         int newest_index = -1;
1946 
1947         newest_index = find_newest_super_backup(info, newest_gen);
1948         /* if there was garbage in there, just move along */
1949         if (newest_index == -1) {
1950                 info->backup_root_index = 0;
1951         } else {
1952                 info->backup_root_index = (newest_index + 1) % BTRFS_NUM_BACKUP_ROOTS;
1953         }
1954 }
1955 
1956 /*
1957  * copy all the root pointers into the super backup array.
1958  * this will bump the backup pointer by one when it is
1959  * done
1960  */
1961 static void backup_super_roots(struct btrfs_fs_info *info)
1962 {
1963         int next_backup;
1964         struct btrfs_root_backup *root_backup;
1965         int last_backup;
1966 
1967         next_backup = info->backup_root_index;
1968         last_backup = (next_backup + BTRFS_NUM_BACKUP_ROOTS - 1) %
1969                 BTRFS_NUM_BACKUP_ROOTS;
1970 
1971         /*
1972          * just overwrite the last backup if we're at the same generation
1973          * this happens only at umount
1974          */
1975         root_backup = info->super_for_commit->super_roots + last_backup;
1976         if (btrfs_backup_tree_root_gen(root_backup) ==
1977             btrfs_header_generation(info->tree_root->node))
1978                 next_backup = last_backup;
1979 
1980         root_backup = info->super_for_commit->super_roots + next_backup;
1981 
1982         /*
1983          * make sure all of our padding and empty slots get zero filled
1984          * regardless of which ones we use today
1985          */
1986         memset(root_backup, 0, sizeof(*root_backup));
1987 
1988         info->backup_root_index = (next_backup + 1) % BTRFS_NUM_BACKUP_ROOTS;
1989 
1990         btrfs_set_backup_tree_root(root_backup, info->tree_root->node->start);
1991         btrfs_set_backup_tree_root_gen(root_backup,
1992                                btrfs_header_generation(info->tree_root->node));
1993 
1994         btrfs_set_backup_tree_root_level(root_backup,
1995                                btrfs_header_level(info->tree_root->node));
1996 
1997         btrfs_set_backup_chunk_root(root_backup, info->chunk_root->node->start);
1998         btrfs_set_backup_chunk_root_gen(root_backup,
1999                                btrfs_header_generation(info->chunk_root->node));
2000         btrfs_set_backup_chunk_root_level(root_backup,
2001                                btrfs_header_level(info->chunk_root->node));
2002 
2003         btrfs_set_backup_extent_root(root_backup, info->extent_root->node->start);
2004         btrfs_set_backup_extent_root_gen(root_backup,
2005                                btrfs_header_generation(info->extent_root->node));
2006         btrfs_set_backup_extent_root_level(root_backup,
2007                                btrfs_header_level(info->extent_root->node));
2008 
2009         /*
2010          * we might commit during log recovery, which happens before we set
2011          * the fs_root.  Make sure it is valid before we fill it in.
2012          */
2013         if (info->fs_root && info->fs_root->node) {
2014                 btrfs_set_backup_fs_root(root_backup,
2015                                          info->fs_root->node->start);
2016                 btrfs_set_backup_fs_root_gen(root_backup,
2017                                btrfs_header_generation(info->fs_root->node));
2018                 btrfs_set_backup_fs_root_level(root_backup,
2019                                btrfs_header_level(info->fs_root->node));
2020         }
2021 
2022         btrfs_set_backup_dev_root(root_backup, info->dev_root->node->start);
2023         btrfs_set_backup_dev_root_gen(root_backup,
2024                                btrfs_header_generation(info->dev_root->node));
2025         btrfs_set_backup_dev_root_level(root_backup,
2026                                        btrfs_header_level(info->dev_root->node));
2027 
2028         btrfs_set_backup_csum_root(root_backup, info->csum_root->node->start);
2029         btrfs_set_backup_csum_root_gen(root_backup,
2030                                btrfs_header_generation(info->csum_root->node));
2031         btrfs_set_backup_csum_root_level(root_backup,
2032                                btrfs_header_level(info->csum_root->node));
2033 
2034         btrfs_set_backup_total_bytes(root_backup,
2035                              btrfs_super_total_bytes(info->super_copy));
2036         btrfs_set_backup_bytes_used(root_backup,
2037                              btrfs_super_bytes_used(info->super_copy));
2038         btrfs_set_backup_num_devices(root_backup,
2039                              btrfs_super_num_devices(info->super_copy));
2040 
2041         /*
2042          * if we don't copy this out to the super_copy, it won't get remembered
2043          * for the next commit
2044          */
2045         memcpy(&info->super_copy->super_roots,
2046                &info->super_for_commit->super_roots,
2047                sizeof(*root_backup) * BTRFS_NUM_BACKUP_ROOTS);
2048 }
2049 
2050 /*
2051  * this copies info out of the root backup array and back into
2052  * the in-memory super block.  It is meant to help iterate through
2053  * the array, so you send it the number of backups you've already
2054  * tried and the last backup index you used.
2055  *
2056  * this returns -1 when it has tried all the backups
2057  */
2058 static noinline int next_root_backup(struct btrfs_fs_info *info,
2059                                      struct btrfs_super_block *super,
2060                                      int *num_backups_tried, int *backup_index)
2061 {
2062         struct btrfs_root_backup *root_backup;
2063         int newest = *backup_index;
2064 
2065         if (*num_backups_tried == 0) {
2066                 u64 gen = btrfs_super_generation(super);
2067 
2068                 newest = find_newest_super_backup(info, gen);
2069                 if (newest == -1)
2070                         return -1;
2071 
2072                 *backup_index = newest;
2073                 *num_backups_tried = 1;
2074         } else if (*num_backups_tried == BTRFS_NUM_BACKUP_ROOTS) {
2075                 /* we've tried all the backups, all done */
2076                 return -1;
2077         } else {
2078                 /* jump to the next oldest backup */
2079                 newest = (*backup_index + BTRFS_NUM_BACKUP_ROOTS - 1) %
2080                         BTRFS_NUM_BACKUP_ROOTS;
2081                 *backup_index = newest;
2082                 *num_backups_tried += 1;
2083         }
2084         root_backup = super->super_roots + newest;
2085 
2086         btrfs_set_super_generation(super,
2087                                    btrfs_backup_tree_root_gen(root_backup));
2088         btrfs_set_super_root(super, btrfs_backup_tree_root(root_backup));
2089         btrfs_set_super_root_level(super,
2090                                    btrfs_backup_tree_root_level(root_backup));
2091         btrfs_set_super_bytes_used(super, btrfs_backup_bytes_used(root_backup));
2092 
2093         /*
2094          * fixme: the total bytes and num_devices need to match or we should
2095          * need a fsck
2096          */
2097         btrfs_set_super_total_bytes(super, btrfs_backup_total_bytes(root_backup));
2098         btrfs_set_super_num_devices(super, btrfs_backup_num_devices(root_backup));
2099         return 0;
2100 }
2101 
2102 /* helper to cleanup workers */
2103 static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
2104 {
2105         btrfs_destroy_workqueue(fs_info->fixup_workers);
2106         btrfs_destroy_workqueue(fs_info->delalloc_workers);
2107         btrfs_destroy_workqueue(fs_info->workers);
2108         btrfs_destroy_workqueue(fs_info->endio_workers);
2109         btrfs_destroy_workqueue(fs_info->endio_meta_workers);
2110         btrfs_destroy_workqueue(fs_info->endio_raid56_workers);
2111         btrfs_destroy_workqueue(fs_info->endio_repair_workers);
2112         btrfs_destroy_workqueue(fs_info->rmw_workers);
2113         btrfs_destroy_workqueue(fs_info->endio_meta_write_workers);
2114         btrfs_destroy_workqueue(fs_info->endio_write_workers);
2115         btrfs_destroy_workqueue(fs_info->endio_freespace_worker);
2116         btrfs_destroy_workqueue(fs_info->submit_workers);
2117         btrfs_destroy_workqueue(fs_info->delayed_workers);
2118         btrfs_destroy_workqueue(fs_info->caching_workers);
2119         btrfs_destroy_workqueue(fs_info->readahead_workers);
2120         btrfs_destroy_workqueue(fs_info->flush_workers);
2121         btrfs_destroy_workqueue(fs_info->qgroup_rescan_workers);
2122         btrfs_destroy_workqueue(fs_info->extent_workers);
2123 }
2124 
2125 static void free_root_extent_buffers(struct btrfs_root *root)
2126 {
2127         if (root) {
2128                 free_extent_buffer(root->node);
2129                 free_extent_buffer(root->commit_root);
2130                 root->node = NULL;
2131                 root->commit_root = NULL;
2132         }
2133 }
2134 
2135 /* helper to cleanup tree roots */
2136 static void free_root_pointers(struct btrfs_fs_info *info, int chunk_root)
2137 {
2138         free_root_extent_buffers(info->tree_root);
2139 
2140         free_root_extent_buffers(info->dev_root);
2141         free_root_extent_buffers(info->extent_root);
2142         free_root_extent_buffers(info->csum_root);
2143         free_root_extent_buffers(info->quota_root);
2144         free_root_extent_buffers(info->uuid_root);
2145         if (chunk_root)
2146                 free_root_extent_buffers(info->chunk_root);
2147 }
2148 
2149 void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info)
2150 {
2151         int ret;
2152         struct btrfs_root *gang[8];
2153         int i;
2154 
2155         while (!list_empty(&fs_info->dead_roots)) {
2156                 gang[0] = list_entry(fs_info->dead_roots.next,
2157                                      struct btrfs_root, root_list);
2158                 list_del(&gang[0]->root_list);
2159 
2160                 if (test_bit(BTRFS_ROOT_IN_RADIX, &gang[0]->state)) {
2161                         btrfs_drop_and_free_fs_root(fs_info, gang[0]);
2162                 } else {
2163                         free_extent_buffer(gang[0]->node);
2164                         free_extent_buffer(gang[0]->commit_root);
2165                         btrfs_put_fs_root(gang[0]);
2166                 }
2167         }
2168 
2169         while (1) {
2170                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2171                                              (void **)gang, 0,
2172                                              ARRAY_SIZE(gang));
2173                 if (!ret)
2174                         break;
2175                 for (i = 0; i < ret; i++)
2176                         btrfs_drop_and_free_fs_root(fs_info, gang[i]);
2177         }
2178 
2179         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
2180                 btrfs_free_log_root_tree(NULL, fs_info);
2181                 btrfs_destroy_pinned_extent(fs_info->tree_root,
2182                                             fs_info->pinned_extents);
2183         }
2184 }
2185 
2186 static void btrfs_init_scrub(struct btrfs_fs_info *fs_info)
2187 {
2188         mutex_init(&fs_info->scrub_lock);
2189         atomic_set(&fs_info->scrubs_running, 0);
2190         atomic_set(&fs_info->scrub_pause_req, 0);
2191         atomic_set(&fs_info->scrubs_paused, 0);
2192         atomic_set(&fs_info->scrub_cancel_req, 0);
2193         init_waitqueue_head(&fs_info->scrub_pause_wait);
2194         fs_info->scrub_workers_refcnt = 0;
2195 }
2196 
2197 static void btrfs_init_balance(struct btrfs_fs_info *fs_info)
2198 {
2199         spin_lock_init(&fs_info->balance_lock);
2200         mutex_init(&fs_info->balance_mutex);
2201         atomic_set(&fs_info->balance_running, 0);
2202         atomic_set(&fs_info->balance_pause_req, 0);
2203         atomic_set(&fs_info->balance_cancel_req, 0);
2204         fs_info->balance_ctl = NULL;
2205         init_waitqueue_head(&fs_info->balance_wait_q);
2206 }
2207 
2208 static void btrfs_init_btree_inode(struct btrfs_fs_info *fs_info,
2209                                    struct btrfs_root *tree_root)
2210 {
2211         fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
2212         set_nlink(fs_info->btree_inode, 1);
2213         /*
2214          * we set the i_size on the btree inode to the max possible int.
2215          * the real end of the address space is determined by all of
2216          * the devices in the system
2217          */
2218         fs_info->btree_inode->i_size = OFFSET_MAX;
2219         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
2220 
2221         RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
2222         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
2223                              fs_info->btree_inode->i_mapping);
2224         BTRFS_I(fs_info->btree_inode)->io_tree.track_uptodate = 0;
2225         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree);
2226 
2227         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
2228 
2229         BTRFS_I(fs_info->btree_inode)->root = tree_root;
2230         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
2231                sizeof(struct btrfs_key));
2232         set_bit(BTRFS_INODE_DUMMY,
2233                 &BTRFS_I(fs_info->btree_inode)->runtime_flags);
2234         btrfs_insert_inode_hash(fs_info->btree_inode);
2235 }
2236 
2237 static void btrfs_init_dev_replace_locks(struct btrfs_fs_info *fs_info)
2238 {
2239         fs_info->dev_replace.lock_owner = 0;
2240         atomic_set(&fs_info->dev_replace.nesting_level, 0);
2241         mutex_init(&fs_info->dev_replace.lock_finishing_cancel_unmount);
2242         mutex_init(&fs_info->dev_replace.lock_management_lock);
2243         mutex_init(&fs_info->dev_replace.lock);
2244         init_waitqueue_head(&fs_info->replace_wait);
2245 }
2246 
2247 static void btrfs_init_qgroup(struct btrfs_fs_info *fs_info)
2248 {
2249         spin_lock_init(&fs_info->qgroup_lock);
2250         mutex_init(&fs_info->qgroup_ioctl_lock);
2251         fs_info->qgroup_tree = RB_ROOT;
2252         fs_info->qgroup_op_tree = RB_ROOT;
2253         INIT_LIST_HEAD(&fs_info->dirty_qgroups);
2254         fs_info->qgroup_seq = 1;
2255         fs_info->quota_enabled = 0;
2256         fs_info->pending_quota_state = 0;
2257         fs_info->qgroup_ulist = NULL;
2258         mutex_init(&fs_info->qgroup_rescan_lock);
2259 }
2260 
2261 static int btrfs_init_workqueues(struct btrfs_fs_info *fs_info,
2262                 struct btrfs_fs_devices *fs_devices)
2263 {
2264         int max_active = fs_info->thread_pool_size;
2265         unsigned int flags = WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_UNBOUND;
2266 
2267         fs_info->workers =
2268                 btrfs_alloc_workqueue("worker", flags | WQ_HIGHPRI,
2269                                       max_active, 16);
2270 
2271         fs_info->delalloc_workers =
2272                 btrfs_alloc_workqueue("delalloc", flags, max_active, 2);
2273 
2274         fs_info->flush_workers =
2275                 btrfs_alloc_workqueue("flush_delalloc", flags, max_active, 0);
2276 
2277         fs_info->caching_workers =
2278                 btrfs_alloc_workqueue("cache", flags, max_active, 0);
2279 
2280         /*
2281          * a higher idle thresh on the submit workers makes it much more
2282          * likely that bios will be send down in a sane order to the
2283          * devices
2284          */
2285         fs_info->submit_workers =
2286                 btrfs_alloc_workqueue("submit", flags,
2287                                       min_t(u64, fs_devices->num_devices,
2288                                             max_active), 64);
2289 
2290         fs_info->fixup_workers =
2291                 btrfs_alloc_workqueue("fixup", flags, 1, 0);
2292 
2293         /*
2294          * endios are largely parallel and should have a very
2295          * low idle thresh
2296          */
2297         fs_info->endio_workers =
2298                 btrfs_alloc_workqueue("endio", flags, max_active, 4);
2299         fs_info->endio_meta_workers =
2300                 btrfs_alloc_workqueue("endio-meta", flags, max_active, 4);
2301         fs_info->endio_meta_write_workers =
2302                 btrfs_alloc_workqueue("endio-meta-write", flags, max_active, 2);
2303         fs_info->endio_raid56_workers =
2304                 btrfs_alloc_workqueue("endio-raid56", flags, max_active, 4);
2305         fs_info->endio_repair_workers =
2306                 btrfs_alloc_workqueue("endio-repair", flags, 1, 0);
2307         fs_info->rmw_workers =
2308                 btrfs_alloc_workqueue("rmw", flags, max_active, 2);
2309         fs_info->endio_write_workers =
2310                 btrfs_alloc_workqueue("endio-write", flags, max_active, 2);
2311         fs_info->endio_freespace_worker =
2312                 btrfs_alloc_workqueue("freespace-write", flags, max_active, 0);
2313         fs_info->delayed_workers =
2314                 btrfs_alloc_workqueue("delayed-meta", flags, max_active, 0);
2315         fs_info->readahead_workers =
2316                 btrfs_alloc_workqueue("readahead", flags, max_active, 2);
2317         fs_info->qgroup_rescan_workers =
2318                 btrfs_alloc_workqueue("qgroup-rescan", flags, 1, 0);
2319         fs_info->extent_workers =
2320                 btrfs_alloc_workqueue("extent-refs", flags,
2321                                       min_t(u64, fs_devices->num_devices,
2322                                             max_active), 8);
2323 
2324         if (!(fs_info->workers && fs_info->delalloc_workers &&
2325               fs_info->submit_workers && fs_info->flush_workers &&
2326               fs_info->endio_workers && fs_info->endio_meta_workers &&
2327               fs_info->endio_meta_write_workers &&
2328               fs_info->endio_repair_workers &&
2329               fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
2330               fs_info->endio_freespace_worker && fs_info->rmw_workers &&
2331               fs_info->caching_workers && fs_info->readahead_workers &&
2332               fs_info->fixup_workers && fs_info->delayed_workers &&
2333               fs_info->extent_workers &&
2334               fs_info->qgroup_rescan_workers)) {
2335                 return -ENOMEM;
2336         }
2337 
2338         return 0;
2339 }
2340 
2341 static int btrfs_replay_log(struct btrfs_fs_info *fs_info,
2342                             struct btrfs_fs_devices *fs_devices)
2343 {
2344         int ret;
2345         struct btrfs_root *tree_root = fs_info->tree_root;
2346         struct btrfs_root *log_tree_root;
2347         struct btrfs_super_block *disk_super = fs_info->super_copy;
2348         u64 bytenr = btrfs_super_log_root(disk_super);
2349 
2350         if (fs_devices->rw_devices == 0) {
2351                 printk(KERN_WARNING "BTRFS: log replay required "
2352                        "on RO media\n");
2353                 return -EIO;
2354         }
2355 
2356         log_tree_root = btrfs_alloc_root(fs_info);
2357         if (!log_tree_root)
2358                 return -ENOMEM;
2359 
2360         __setup_root(tree_root->nodesize, tree_root->sectorsize,
2361                         tree_root->stripesize, log_tree_root, fs_info,
2362                         BTRFS_TREE_LOG_OBJECTID);
2363 
2364         log_tree_root->node = read_tree_block(tree_root, bytenr,
2365                         fs_info->generation + 1);
2366         if (IS_ERR(log_tree_root->node)) {
2367                 printk(KERN_ERR "BTRFS: failed to read log tree\n");
2368                 ret = PTR_ERR(log_tree_root->node);
2369                 kfree(log_tree_root);
2370                 return ret;
2371         } else if (!extent_buffer_uptodate(log_tree_root->node)) {
2372                 printk(KERN_ERR "BTRFS: failed to read log tree\n");
2373                 free_extent_buffer(log_tree_root->node);
2374                 kfree(log_tree_root);
2375                 return -EIO;
2376         }
2377         /* returns with log_tree_root freed on success */
2378         ret = btrfs_recover_log_trees(log_tree_root);
2379         if (ret) {
2380                 btrfs_error(tree_root->fs_info, ret,
2381                             "Failed to recover log tree");
2382                 free_extent_buffer(log_tree_root->node);
2383                 kfree(log_tree_root);
2384                 return ret;
2385         }
2386 
2387         if (fs_info->sb->s_flags & MS_RDONLY) {
2388                 ret = btrfs_commit_super(tree_root);
2389                 if (ret)
2390                         return ret;
2391         }
2392 
2393         return 0;
2394 }
2395 
2396 static int btrfs_read_roots(struct btrfs_fs_info *fs_info,
2397                             struct btrfs_root *tree_root)
2398 {
2399         struct btrfs_root *root;
2400         struct btrfs_key location;
2401         int ret;
2402 
2403         location.objectid = BTRFS_EXTENT_TREE_OBJECTID;
2404         location.type = BTRFS_ROOT_ITEM_KEY;
2405         location.offset = 0;
2406 
2407         root = btrfs_read_tree_root(tree_root, &location);
2408         if (IS_ERR(root))
2409                 return PTR_ERR(root);
2410         set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2411         fs_info->extent_root = root;
2412 
2413         location.objectid = BTRFS_DEV_TREE_OBJECTID;
2414         root = btrfs_read_tree_root(tree_root, &location);
2415         if (IS_ERR(root))
2416                 return PTR_ERR(root);
2417         set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2418         fs_info->dev_root = root;
2419         btrfs_init_devices_late(fs_info);
2420 
2421         location.objectid = BTRFS_CSUM_TREE_OBJECTID;
2422         root = btrfs_read_tree_root(tree_root, &location);
2423         if (IS_ERR(root))
2424                 return PTR_ERR(root);
2425         set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2426         fs_info->csum_root = root;
2427 
2428         location.objectid = BTRFS_QUOTA_TREE_OBJECTID;
2429         root = btrfs_read_tree_root(tree_root, &location);
2430         if (!IS_ERR(root)) {
2431                 set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2432                 fs_info->quota_enabled = 1;
2433                 fs_info->pending_quota_state = 1;
2434                 fs_info->quota_root = root;
2435         }
2436 
2437         location.objectid = BTRFS_UUID_TREE_OBJECTID;
2438         root = btrfs_read_tree_root(tree_root, &location);
2439         if (IS_ERR(root)) {
2440                 ret = PTR_ERR(root);
2441                 if (ret != -ENOENT)
2442                         return ret;
2443         } else {
2444                 set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2445                 fs_info->uuid_root = root;
2446         }
2447 
2448         return 0;
2449 }
2450 
2451 int open_ctree(struct super_block *sb,
2452                struct btrfs_fs_devices *fs_devices,
2453                char *options)
2454 {
2455         u32 sectorsize;
2456         u32 nodesize;
2457         u32 stripesize;
2458         u64 generation;
2459         u64 features;
2460         struct btrfs_key location;
2461         struct buffer_head *bh;
2462         struct btrfs_super_block *disk_super;
2463         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2464         struct btrfs_root *tree_root;
2465         struct btrfs_root *chunk_root;
2466         int ret;
2467         int err = -EINVAL;
2468         int num_backups_tried = 0;
2469         int backup_index = 0;
2470         int max_active;
2471 
2472         tree_root = fs_info->tree_root = btrfs_alloc_root(fs_info);
2473         chunk_root = fs_info->chunk_root = btrfs_alloc_root(fs_info);
2474         if (!tree_root || !chunk_root) {
2475                 err = -ENOMEM;
2476                 goto fail;
2477         }
2478 
2479         ret = init_srcu_struct(&fs_info->subvol_srcu);
2480         if (ret) {
2481                 err = ret;
2482                 goto fail;
2483         }
2484 
2485         ret = setup_bdi(fs_info, &fs_info->bdi);
2486         if (ret) {
2487                 err = ret;
2488                 goto fail_srcu;
2489         }
2490 
2491         ret = percpu_counter_init(&fs_info->dirty_metadata_bytes, 0, GFP_KERNEL);
2492         if (ret) {
2493                 err = ret;
2494                 goto fail_bdi;
2495         }
2496         fs_info->dirty_metadata_batch = PAGE_CACHE_SIZE *
2497                                         (1 + ilog2(nr_cpu_ids));
2498 
2499         ret = percpu_counter_init(&fs_info->delalloc_bytes, 0, GFP_KERNEL);
2500         if (ret) {
2501                 err = ret;
2502                 goto fail_dirty_metadata_bytes;
2503         }
2504 
2505         ret = percpu_counter_init(&fs_info->bio_counter, 0, GFP_KERNEL);
2506         if (ret) {
2507                 err = ret;
2508                 goto fail_delalloc_bytes;
2509         }
2510 
2511         fs_info->btree_inode = new_inode(sb);
2512         if (!fs_info->btree_inode) {
2513                 err = -ENOMEM;
2514                 goto fail_bio_counter;
2515         }
2516 
2517         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
2518 
2519         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
2520         INIT_RADIX_TREE(&fs_info->buffer_radix, GFP_ATOMIC);
2521         INIT_LIST_HEAD(&fs_info->trans_list);
2522         INIT_LIST_HEAD(&fs_info->dead_roots);
2523         INIT_LIST_HEAD(&fs_info->delayed_iputs);
2524         INIT_LIST_HEAD(&fs_info->delalloc_roots);
2525         INIT_LIST_HEAD(&fs_info->caching_block_groups);
2526         spin_lock_init(&fs_info->delalloc_root_lock);
2527         spin_lock_init(&fs_info->trans_lock);
2528         spin_lock_init(&fs_info->fs_roots_radix_lock);
2529         spin_lock_init(&fs_info->delayed_iput_lock);
2530         spin_lock_init(&fs_info->defrag_inodes_lock);
2531         spin_lock_init(&fs_info->free_chunk_lock);
2532         spin_lock_init(&fs_info->tree_mod_seq_lock);
2533         spin_lock_init(&fs_info->super_lock);
2534         spin_lock_init(&fs_info->qgroup_op_lock);
2535         spin_lock_init(&fs_info->buffer_lock);
2536         spin_lock_init(&fs_info->unused_bgs_lock);
2537         rwlock_init(&fs_info->tree_mod_log_lock);
2538         mutex_init(&fs_info->unused_bg_unpin_mutex);
2539         mutex_init(&fs_info->delete_unused_bgs_mutex);
2540         mutex_init(&fs_info->reloc_mutex);
2541         mutex_init(&fs_info->delalloc_root_mutex);
2542         seqlock_init(&fs_info->profiles_lock);
2543         init_rwsem(&fs_info->delayed_iput_sem);
2544 
2545         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
2546         INIT_LIST_HEAD(&fs_info->space_info);
2547         INIT_LIST_HEAD(&fs_info->tree_mod_seq_list);
2548         INIT_LIST_HEAD(&fs_info->unused_bgs);
2549         btrfs_mapping_init(&fs_info->mapping_tree);
2550         btrfs_init_block_rsv(&fs_info->global_block_rsv,
2551                              BTRFS_BLOCK_RSV_GLOBAL);
2552         btrfs_init_block_rsv(&fs_info->delalloc_block_rsv,
2553                              BTRFS_BLOCK_RSV_DELALLOC);
2554         btrfs_init_block_rsv(&fs_info->trans_block_rsv, BTRFS_BLOCK_RSV_TRANS);
2555         btrfs_init_block_rsv(&fs_info->chunk_block_rsv, BTRFS_BLOCK_RSV_CHUNK);
2556         btrfs_init_block_rsv(&fs_info->empty_block_rsv, BTRFS_BLOCK_RSV_EMPTY);
2557         btrfs_init_block_rsv(&fs_info->delayed_block_rsv,
2558                              BTRFS_BLOCK_RSV_DELOPS);
2559         atomic_set(&fs_info->nr_async_submits, 0);
2560         atomic_set(&fs_info->async_delalloc_pages, 0);
2561         atomic_set(&fs_info->async_submit_draining, 0);
2562         atomic_set(&fs_info->nr_async_bios, 0);
2563         atomic_set(&fs_info->defrag_running, 0);
2564         atomic_set(&fs_info->qgroup_op_seq, 0);
2565         atomic64_set(&fs_info->tree_mod_seq, 0);
2566         fs_info->sb = sb;
2567         fs_info->max_inline = BTRFS_DEFAULT_MAX_INLINE;
2568         fs_info->metadata_ratio = 0;
2569         fs_info->defrag_inodes = RB_ROOT;
2570         fs_info->free_chunk_space = 0;
2571         fs_info->tree_mod_log = RB_ROOT;
2572         fs_info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
2573         fs_info->avg_delayed_ref_runtime = NSEC_PER_SEC >> 6; /* div by 64 */
2574         /* readahead state */
2575         INIT_RADIX_TREE(&fs_info->reada_tree, GFP_NOFS & ~__GFP_WAIT);
2576         spin_lock_init(&fs_info->reada_lock);
2577 
2578         fs_info->thread_pool_size = min_t(unsigned long,
2579                                           num_online_cpus() + 2, 8);
2580 
2581         INIT_LIST_HEAD(&fs_info->ordered_roots);
2582         spin_lock_init(&fs_info->ordered_root_lock);
2583         fs_info->delayed_root = kmalloc(sizeof(struct btrfs_delayed_root),
2584                                         GFP_NOFS);
2585         if (!fs_info->delayed_root) {
2586                 err = -ENOMEM;
2587                 goto fail_iput;
2588         }
2589         btrfs_init_delayed_root(fs_info->delayed_root);
2590 
2591         btrfs_init_scrub(fs_info);
2592 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2593         fs_info->check_integrity_print_mask = 0;
2594 #endif
2595         btrfs_init_balance(fs_info);
2596         btrfs_init_async_reclaim_work(&fs_info->async_reclaim_work);
2597 
2598         sb->s_blocksize = 4096;
2599         sb->s_blocksize_bits = blksize_bits(4096);
2600         sb->s_bdi = &fs_info->bdi;
2601 
2602         btrfs_init_btree_inode(fs_info, tree_root);
2603 
2604         spin_lock_init(&fs_info->block_group_cache_lock);
2605         fs_info->block_group_cache_tree = RB_ROOT;
2606         fs_info->first_logical_byte = (u64)-1;
2607 
2608         extent_io_tree_init(&fs_info->freed_extents[0],
2609                              fs_info->btree_inode->i_mapping);
2610         extent_io_tree_init(&fs_info->freed_extents[1],
2611                              fs_info->btree_inode->i_mapping);
2612         fs_info->pinned_extents = &fs_info->freed_extents[0];
2613         fs_info->do_barriers = 1;
2614 
2615 
2616         mutex_init(&fs_info->ordered_operations_mutex);
2617         mutex_init(&fs_info->tree_log_mutex);
2618         mutex_init(&fs_info->chunk_mutex);
2619         mutex_init(&fs_info->transaction_kthread_mutex);
2620         mutex_init(&fs_info->cleaner_mutex);
2621         mutex_init(&fs_info->volume_mutex);
2622         mutex_init(&fs_info->ro_block_group_mutex);
2623         init_rwsem(&fs_info->commit_root_sem);
2624         init_rwsem(&fs_info->cleanup_work_sem);
2625         init_rwsem(&fs_info->subvol_sem);
2626         sema_init(&fs_info->uuid_tree_rescan_sem, 1);
2627 
2628         btrfs_init_dev_replace_locks(fs_info);
2629         btrfs_init_qgroup(fs_info);
2630 
2631         btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
2632         btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
2633 
2634         init_waitqueue_head(&fs_info->transaction_throttle);
2635         init_waitqueue_head(&fs_info->transaction_wait);
2636         init_waitqueue_head(&fs_info->transaction_blocked_wait);
2637         init_waitqueue_head(&fs_info->async_submit_wait);
2638 
2639         INIT_LIST_HEAD(&fs_info->pinned_chunks);
2640 
2641         ret = btrfs_alloc_stripe_hash_table(fs_info);
2642         if (ret) {
2643                 err = ret;
2644                 goto fail_alloc;
2645         }
2646 
2647         __setup_root(4096, 4096, 4096, tree_root,
2648                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
2649 
2650         invalidate_bdev(fs_devices->latest_bdev);
2651 
2652         /*
2653          * Read super block and check the signature bytes only
2654          */
2655         bh = btrfs_read_dev_super(fs_devices->latest_bdev);
2656         if (!bh) {
2657                 err = -EINVAL;
2658                 goto fail_alloc;
2659         }
2660 
2661         /*
2662          * We want to check superblock checksum, the type is stored inside.
2663          * Pass the whole disk block of size BTRFS_SUPER_INFO_SIZE (4k).
2664          */
2665         if (btrfs_check_super_csum(bh->b_data)) {
2666                 printk(KERN_ERR "BTRFS: superblock checksum mismatch\n");
2667                 err = -EINVAL;
2668                 goto fail_alloc;
2669         }
2670 
2671         /*
2672          * super_copy is zeroed at allocation time and we never touch the
2673          * following bytes up to INFO_SIZE, the checksum is calculated from
2674          * the whole block of INFO_SIZE
2675          */
2676         memcpy(fs_info->super_copy, bh->b_data, sizeof(*fs_info->super_copy));
2677         memcpy(fs_info->super_for_commit, fs_info->super_copy,
2678                sizeof(*fs_info->super_for_commit));
2679         brelse(bh);
2680 
2681         memcpy(fs_info->fsid, fs_info->super_copy->fsid, BTRFS_FSID_SIZE);
2682 
2683         ret = btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY);
2684         if (ret) {
2685                 printk(KERN_ERR "BTRFS: superblock contains fatal errors\n");
2686                 err = -EINVAL;
2687                 goto fail_alloc;
2688         }
2689 
2690         disk_super = fs_info->super_copy;
2691         if (!btrfs_super_root(disk_super))
2692                 goto fail_alloc;
2693 
2694         /* check FS state, whether FS is broken. */
2695         if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_ERROR)
2696                 set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
2697 
2698         /*
2699          * run through our array of backup supers and setup
2700          * our ring pointer to the oldest one
2701          */
2702         generation = btrfs_super_generation(disk_super);
2703         find_oldest_super_backup(fs_info, generation);
2704 
2705         /*
2706          * In the long term, we'll store the compression type in the super
2707          * block, and it'll be used for per file compression control.
2708          */
2709         fs_info->compress_type = BTRFS_COMPRESS_ZLIB;
2710 
2711         ret = btrfs_parse_options(tree_root, options);
2712         if (ret) {
2713                 err = ret;
2714                 goto fail_alloc;
2715         }
2716 
2717         features = btrfs_super_incompat_flags(disk_super) &
2718                 ~BTRFS_FEATURE_INCOMPAT_SUPP;
2719         if (features) {
2720                 printk(KERN_ERR "BTRFS: couldn't mount because of "
2721                        "unsupported optional features (%Lx).\n",
2722                        features);
2723                 err = -EINVAL;
2724                 goto fail_alloc;
2725         }
2726 
2727         /*
2728          * Leafsize and nodesize were always equal, this is only a sanity check.
2729          */
2730         if (le32_to_cpu(disk_super->__unused_leafsize) !=
2731             btrfs_super_nodesize(disk_super)) {
2732                 printk(KERN_ERR "BTRFS: couldn't mount because metadata "
2733                        "blocksizes don't match.  node %d leaf %d\n",
2734                        btrfs_super_nodesize(disk_super),
2735                        le32_to_cpu(disk_super->__unused_leafsize));
2736                 err = -EINVAL;
2737                 goto fail_alloc;
2738         }
2739         if (btrfs_super_nodesize(disk_super) > BTRFS_MAX_METADATA_BLOCKSIZE) {
2740                 printk(KERN_ERR "BTRFS: couldn't mount because metadata "
2741                        "blocksize (%d) was too large\n",
2742                        btrfs_super_nodesize(disk_super));
2743                 err = -EINVAL;
2744                 goto fail_alloc;
2745         }
2746 
2747         features = btrfs_super_incompat_flags(disk_super);
2748         features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
2749         if (tree_root->fs_info->compress_type == BTRFS_COMPRESS_LZO)
2750                 features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
2751 
2752         if (features & BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA)
2753                 printk(KERN_INFO "BTRFS: has skinny extents\n");
2754 
2755         /*
2756          * flag our filesystem as having big metadata blocks if
2757          * they are bigger than the page size
2758          */
2759         if (btrfs_super_nodesize(disk_super) > PAGE_CACHE_SIZE) {
2760                 if (!(features & BTRFS_FEATURE_INCOMPAT_BIG_METADATA))
2761                         printk(KERN_INFO "BTRFS: flagging fs with big metadata feature\n");
2762                 features |= BTRFS_FEATURE_INCOMPAT_BIG_METADATA;
2763         }
2764 
2765         nodesize = btrfs_super_nodesize(disk_super);
2766         sectorsize = btrfs_super_sectorsize(disk_super);
2767         stripesize = btrfs_super_stripesize(disk_super);
2768         fs_info->dirty_metadata_batch = nodesize * (1 + ilog2(nr_cpu_ids));
2769         fs_info->delalloc_batch = sectorsize * 512 * (1 + ilog2(nr_cpu_ids));
2770 
2771         /*
2772          * mixed block groups end up with duplicate but slightly offset
2773          * extent buffers for the same range.  It leads to corruptions
2774          */
2775         if ((features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS) &&
2776             (sectorsize != nodesize)) {
2777                 printk(KERN_ERR "BTRFS: unequal leaf/node/sector sizes "
2778                                 "are not allowed for mixed block groups on %s\n",
2779                                 sb->s_id);
2780                 goto fail_alloc;
2781         }
2782 
2783         /*
2784          * Needn't use the lock because there is no other task which will
2785          * update the flag.
2786          */
2787         btrfs_set_super_incompat_flags(disk_super, features);
2788 
2789         features = btrfs_super_compat_ro_flags(disk_super) &
2790                 ~BTRFS_FEATURE_COMPAT_RO_SUPP;
2791         if (!(sb->s_flags & MS_RDONLY) && features) {
2792                 printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
2793                        "unsupported option features (%Lx).\n",
2794                        features);
2795                 err = -EINVAL;
2796                 goto fail_alloc;
2797         }
2798 
2799         max_active = fs_info->thread_pool_size;
2800 
2801         ret = btrfs_init_workqueues(fs_info, fs_devices);
2802         if (ret) {
2803                 err = ret;
2804                 goto fail_sb_buffer;
2805         }
2806 
2807         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
2808         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
2809                                     4 * 1024 * 1024 / PAGE_CACHE_SIZE);
2810 
2811         tree_root->nodesize = nodesize;
2812         tree_root->sectorsize = sectorsize;
2813         tree_root->stripesize = stripesize;
2814 
2815         sb->s_blocksize = sectorsize;
2816         sb->s_blocksize_bits = blksize_bits(sectorsize);
2817 
2818         if (btrfs_super_magic(disk_super) != BTRFS_MAGIC) {
2819                 printk(KERN_ERR "BTRFS: valid FS not found on %s\n", sb->s_id);
2820                 goto fail_sb_buffer;
2821         }
2822 
2823         if (sectorsize != PAGE_SIZE) {
2824                 printk(KERN_ERR "BTRFS: incompatible sector size (%lu) "
2825                        "found on %s\n", (unsigned long)sectorsize, sb->s_id);
2826                 goto fail_sb_buffer;
2827         }
2828 
2829         mutex_lock(&fs_info->chunk_mutex);
2830         ret = btrfs_read_sys_array(tree_root);
2831         mutex_unlock(&fs_info->chunk_mutex);
2832         if (ret) {
2833                 printk(KERN_ERR "BTRFS: failed to read the system "
2834                        "array on %s\n", sb->s_id);
2835                 goto fail_sb_buffer;
2836         }
2837 
2838         generation = btrfs_super_chunk_root_generation(disk_super);
2839 
2840         __setup_root(nodesize, sectorsize, stripesize, chunk_root,
2841                      fs_info, BTRFS_CHUNK_TREE_OBJECTID);
2842 
2843         chunk_root->node = read_tree_block(chunk_root,
2844                                            btrfs_super_chunk_root(disk_super),
2845                                            generation);
2846         if (IS_ERR(chunk_root->node) ||
2847             !extent_buffer_uptodate(chunk_root->node)) {
2848                 printk(KERN_ERR "BTRFS: failed to read chunk root on %s\n",
2849                        sb->s_id);
2850                 if (!IS_ERR(chunk_root->node))
2851                         free_extent_buffer(chunk_root->node);
2852                 chunk_root->node = NULL;
2853                 goto fail_tree_roots;
2854         }
2855         btrfs_set_root_node(&chunk_root->root_item, chunk_root->node);
2856         chunk_root->commit_root = btrfs_root_node(chunk_root);
2857 
2858         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
2859            btrfs_header_chunk_tree_uuid(chunk_root->node), BTRFS_UUID_SIZE);
2860 
2861         ret = btrfs_read_chunk_tree(chunk_root);
2862         if (ret) {
2863                 printk(KERN_ERR "BTRFS: failed to read chunk tree on %s\n",
2864                        sb->s_id);
2865                 goto fail_tree_roots;
2866         }
2867 
2868         /*
2869          * keep the device that is marked to be the target device for the
2870          * dev_replace procedure
2871          */
2872         btrfs_close_extra_devices(fs_devices, 0);
2873 
2874         if (!fs_devices->latest_bdev) {
2875                 printk(KERN_ERR "BTRFS: failed to read devices on %s\n",
2876                        sb->s_id);
2877                 goto fail_tree_roots;
2878         }
2879 
2880 retry_root_backup:
2881         generation = btrfs_super_generation(disk_super);
2882 
2883         tree_root->node = read_tree_block(tree_root,
2884                                           btrfs_super_root(disk_super),
2885                                           generation);
2886         if (IS_ERR(tree_root->node) ||
2887             !extent_buffer_uptodate(tree_root->node)) {
2888                 printk(KERN_WARNING "BTRFS: failed to read tree root on %s\n",
2889                        sb->s_id);
2890                 if (!IS_ERR(tree_root->node))
2891                         free_extent_buffer(tree_root->node);
2892                 tree_root->node = NULL;
2893                 goto recovery_tree_root;
2894         }
2895 
2896         btrfs_set_root_node(&tree_root->root_item, tree_root->node);
2897         tree_root->commit_root = btrfs_root_node(tree_root);
2898         btrfs_set_root_refs(&tree_root->root_item, 1);
2899 
2900         ret = btrfs_read_roots(fs_info, tree_root);
2901         if (ret)
2902                 goto recovery_tree_root;
2903 
2904         fs_info->generation = generation;
2905         fs_info->last_trans_committed = generation;
2906 
2907         ret = btrfs_recover_balance(fs_info);
2908         if (ret) {
2909                 printk(KERN_ERR "BTRFS: failed to recover balance\n");
2910                 goto fail_block_groups;
2911         }
2912 
2913         ret = btrfs_init_dev_stats(fs_info);
2914         if (ret) {
2915                 printk(KERN_ERR "BTRFS: failed to init dev_stats: %d\n",
2916                        ret);
2917                 goto fail_block_groups;
2918         }
2919 
2920         ret = btrfs_init_dev_replace(fs_info);
2921         if (ret) {
2922                 pr_err("BTRFS: failed to init dev_replace: %d\n", ret);
2923                 goto fail_block_groups;
2924         }
2925 
2926         btrfs_close_extra_devices(fs_devices, 1);
2927 
2928         ret = btrfs_sysfs_add_fsid(fs_devices, NULL);
2929         if (ret) {
2930                 pr_err("BTRFS: failed to init sysfs fsid interface: %d\n", ret);
2931                 goto fail_block_groups;
2932         }
2933 
2934         ret = btrfs_sysfs_add_device(fs_devices);
2935         if (ret) {
2936                 pr_err("BTRFS: failed to init sysfs device interface: %d\n", ret);
2937                 goto fail_fsdev_sysfs;
2938         }
2939 
2940         ret = btrfs_sysfs_add_one(fs_info);
2941         if (ret) {
2942                 pr_err("BTRFS: failed to init sysfs interface: %d\n", ret);
2943                 goto fail_fsdev_sysfs;
2944         }
2945 
2946         ret = btrfs_init_space_info(fs_info);
2947         if (ret) {
2948                 printk(KERN_ERR "BTRFS: Failed to initial space info: %d\n", ret);
2949                 goto fail_sysfs;
2950         }
2951 
2952         ret = btrfs_read_block_groups(fs_info->extent_root);
2953         if (ret) {
2954                 printk(KERN_ERR "BTRFS: Failed to read block groups: %d\n", ret);
2955                 goto fail_sysfs;
2956         }
2957         fs_info->num_tolerated_disk_barrier_failures =
2958                 btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
2959         if (fs_info->fs_devices->missing_devices >
2960              fs_info->num_tolerated_disk_barrier_failures &&
2961             !(sb->s_flags & MS_RDONLY)) {
2962                 pr_warn("BTRFS: missing devices(%llu) exceeds the limit(%d), writeable mount is not allowed\n",
2963                         fs_info->fs_devices->missing_devices,
2964                         fs_info->num_tolerated_disk_barrier_failures);
2965                 goto fail_sysfs;
2966         }
2967 
2968         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
2969                                                "btrfs-cleaner");
2970         if (IS_ERR(fs_info->cleaner_kthread))
2971                 goto fail_sysfs;
2972 
2973         fs_info->transaction_kthread = kthread_run(transaction_kthread,
2974                                                    tree_root,
2975                                                    "btrfs-transaction");
2976         if (IS_ERR(fs_info->transaction_kthread))
2977                 goto fail_cleaner;
2978 
2979         if (!btrfs_test_opt(tree_root, SSD) &&
2980             !btrfs_test_opt(tree_root, NOSSD) &&
2981             !fs_info->fs_devices->rotating) {
2982                 printk(KERN_INFO "BTRFS: detected SSD devices, enabling SSD "
2983                        "mode\n");
2984                 btrfs_set_opt(fs_info->mount_opt, SSD);
2985         }
2986 
2987         /*
2988          * Mount does not set all options immediatelly, we can do it now and do
2989          * not have to wait for transaction commit
2990          */
2991         btrfs_apply_pending_changes(fs_info);
2992 
2993 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2994         if (btrfs_test_opt(tree_root, CHECK_INTEGRITY)) {
2995                 ret = btrfsic_mount(tree_root, fs_devices,
2996                                     btrfs_test_opt(tree_root,
2997                                         CHECK_INTEGRITY_INCLUDING_EXTENT_DATA) ?
2998                                     1 : 0,
2999                                     fs_info->check_integrity_print_mask);
3000                 if (ret)
3001                         printk(KERN_WARNING "BTRFS: failed to initialize"
3002                                " integrity check module %s\n", sb->s_id);
3003         }
3004 #endif
3005         ret = btrfs_read_qgroup_config(fs_info);
3006         if (ret)
3007                 goto fail_trans_kthread;
3008 
3009         /* do not make disk changes in broken FS */
3010         if (btrfs_super_log_root(disk_super) != 0) {
3011                 ret = btrfs_replay_log(fs_info, fs_devices);
3012                 if (ret) {
3013                         err = ret;
3014                         goto fail_qgroup;
3015                 }
3016         }
3017 
3018         ret = btrfs_find_orphan_roots(tree_root);
3019         if (ret)
3020                 goto fail_qgroup;
3021 
3022         if (!(sb->s_flags & MS_RDONLY)) {
3023                 ret = btrfs_cleanup_fs_roots(fs_info);
3024                 if (ret)
3025                         goto fail_qgroup;
3026 
3027                 mutex_lock(&fs_info->cleaner_mutex);
3028                 ret = btrfs_recover_relocation(tree_root);
3029                 mutex_unlock(&fs_info->cleaner_mutex);
3030                 if (ret < 0) {
3031                         printk(KERN_WARNING
3032                                "BTRFS: failed to recover relocation\n");
3033                         err = -EINVAL;
3034                         goto fail_qgroup;
3035                 }
3036         }
3037 
3038         location.objectid = BTRFS_FS_TREE_OBJECTID;
3039         location.type = BTRFS_ROOT_ITEM_KEY;
3040         location.offset = 0;
3041 
3042         fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
3043         if (IS_ERR(fs_info->fs_root)) {
3044                 err = PTR_ERR(fs_info->fs_root);
3045                 goto fail_qgroup;
3046         }
3047 
3048         if (sb->s_flags & MS_RDONLY)
3049                 return 0;
3050 
3051         down_read(&fs_info->cleanup_work_sem);
3052         if ((ret = btrfs_orphan_cleanup(fs_info->fs_root)) ||
3053             (ret = btrfs_orphan_cleanup(fs_info->tree_root))) {
3054                 up_read(&fs_info->cleanup_work_sem);
3055                 close_ctree(tree_root);
3056                 return ret;
3057         }
3058         up_read(&fs_info->cleanup_work_sem);
3059 
3060         ret = btrfs_resume_balance_async(fs_info);
3061         if (ret) {
3062                 printk(KERN_WARNING "BTRFS: failed to resume balance\n");
3063                 close_ctree(tree_root);
3064                 return ret;
3065         }
3066 
3067         ret = btrfs_resume_dev_replace_async(fs_info);
3068         if (ret) {
3069                 pr_warn("BTRFS: failed to resume dev_replace\n");
3070                 close_ctree(tree_root);
3071                 return ret;
3072         }
3073 
3074         btrfs_qgroup_rescan_resume(fs_info);
3075 
3076         if (!fs_info->uuid_root) {
3077                 pr_info("BTRFS: creating UUID tree\n");
3078                 ret = btrfs_create_uuid_tree(fs_info);
3079                 if (ret) {
3080                         pr_warn("BTRFS: failed to create the UUID tree %d\n",
3081                                 ret);
3082                         close_ctree(tree_root);
3083                         return ret;
3084                 }
3085         } else if (btrfs_test_opt(tree_root, RESCAN_UUID_TREE) ||
3086                    fs_info->generation !=
3087                                 btrfs_super_uuid_tree_generation(disk_super)) {
3088                 pr_info("BTRFS: checking UUID tree\n");
3089                 ret = btrfs_check_uuid_tree(fs_info);
3090                 if (ret) {
3091                         pr_warn("BTRFS: failed to check the UUID tree %d\n",
3092                                 ret);
3093                         close_ctree(tree_root);
3094                         return ret;
3095                 }
3096         } else {
3097                 fs_info->update_uuid_tree_gen = 1;
3098         }
3099 
3100         fs_info->open = 1;
3101 
3102         return 0;
3103 
3104 fail_qgroup:
3105         btrfs_free_qgroup_config(fs_info);
3106 fail_trans_kthread:
3107         kthread_stop(fs_info->transaction_kthread);
3108         btrfs_cleanup_transaction(fs_info->tree_root);
3109         btrfs_free_fs_roots(fs_info);
3110 fail_cleaner:
3111         kthread_stop(fs_info->cleaner_kthread);
3112 
3113         /*
3114          * make sure we're done with the btree inode before we stop our
3115          * kthreads
3116          */
3117         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
3118 
3119 fail_sysfs:
3120         btrfs_sysfs_remove_one(fs_info);
3121 
3122 fail_fsdev_sysfs:
3123         btrfs_sysfs_remove_fsid(fs_info->fs_devices);
3124 
3125 fail_block_groups:
3126         btrfs_put_block_group_cache(fs_info);
3127         btrfs_free_block_groups(fs_info);
3128 
3129 fail_tree_roots:
3130         free_root_pointers(fs_info, 1);
3131         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
3132 
3133 fail_sb_buffer:
3134         btrfs_stop_all_workers(fs_info);
3135 fail_alloc:
3136 fail_iput:
3137         btrfs_mapping_tree_free(&fs_info->mapping_tree);
3138 
3139         iput(fs_info->btree_inode);
3140 fail_bio_counter:
3141         percpu_counter_destroy(&fs_info->bio_counter);
3142 fail_delalloc_bytes:
3143         percpu_counter_destroy(&fs_info->delalloc_bytes);
3144 fail_dirty_metadata_bytes:
3145         percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
3146 fail_bdi:
3147         bdi_destroy(&fs_info->bdi);
3148 fail_srcu:
3149         cleanup_srcu_struct(&fs_info->subvol_srcu);
3150 fail:
3151         btrfs_free_stripe_hash_table(fs_info);
3152         btrfs_close_devices(fs_info->fs_devices);
3153         return err;
3154 
3155 recovery_tree_root:
3156         if (!btrfs_test_opt(tree_root, RECOVERY))
3157                 goto fail_tree_roots;
3158 
3159         free_root_pointers(fs_info, 0);
3160 
3161         /* don't use the log in recovery mode, it won't be valid */
3162         btrfs_set_super_log_root(disk_super, 0);
3163 
3164         /* we can't trust the free space cache either */
3165         btrfs_set_opt(fs_info->mount_opt, CLEAR_CACHE);
3166 
3167         ret = next_root_backup(fs_info, fs_info->super_copy,
3168                                &num_backups_tried, &backup_index);
3169         if (ret == -1)
3170                 goto fail_block_groups;
3171         goto retry_root_backup;
3172 }
3173 
3174 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
3175 {
3176         if (uptodate) {
3177                 set_buffer_uptodate(bh);
3178         } else {
3179                 struct btrfs_device *device = (struct btrfs_device *)
3180                         bh->b_private;
3181 
3182                 printk_ratelimited_in_rcu(KERN_WARNING "BTRFS: lost page write due to "
3183                                           "I/O error on %s\n",
3184                                           rcu_str_deref(device->name));
3185                 /* note, we dont' set_buffer_write_io_error because we have
3186                  * our own ways of dealing with the IO errors
3187                  */
3188                 clear_buffer_uptodate(bh);
3189                 btrfs_dev_stat_inc_and_print(device, BTRFS_DEV_STAT_WRITE_ERRS);
3190         }
3191         unlock_buffer(bh);
3192         put_bh(bh);
3193 }
3194 
3195 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
3196 {
3197         struct buffer_head *bh;
3198         struct buffer_head *latest = NULL;
3199         struct btrfs_super_block *super;
3200         int i;
3201         u64 transid = 0;
3202         u64 bytenr;
3203 
3204         /* we would like to check all the supers, but that would make
3205          * a btrfs mount succeed after a mkfs from a different FS.
3206          * So, we need to add a special mount option to scan for
3207          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
3208          */
3209         for (i = 0; i < 1; i++) {
3210                 bytenr = btrfs_sb_offset(i);
3211                 if (bytenr + BTRFS_SUPER_INFO_SIZE >=
3212                                         i_size_read(bdev->bd_inode))
3213                         break;
3214                 bh = __bread(bdev, bytenr / 4096,
3215                                         BTRFS_SUPER_INFO_SIZE);
3216                 if (!bh)
3217                         continue;
3218 
3219                 super = (struct btrfs_super_block *)bh->b_data;
3220                 if (btrfs_super_bytenr(super) != bytenr ||
3221                     btrfs_super_magic(super) != BTRFS_MAGIC) {
3222                         brelse(bh);
3223                         continue;
3224                 }
3225 
3226                 if (!latest || btrfs_super_generation(super) > transid) {
3227                         brelse(latest);
3228                         latest = bh;
3229                         transid = btrfs_super_generation(super);
3230                 } else {
3231                         brelse(bh);
3232                 }
3233         }
3234         return latest;
3235 }
3236 
3237 /*
3238  * this should be called twice, once with wait == 0 and
3239  * once with wait == 1.  When wait == 0 is done, all the buffer heads
3240  * we write are pinned.
3241  *
3242  * They are released when wait == 1 is done.
3243  * max_mirrors must be the same for both runs, and it indicates how
3244  * many supers on this one device should be written.
3245  *
3246  * max_mirrors == 0 means to write them all.
3247  */
3248 static int write_dev_supers(struct btrfs_device *device,
3249                             struct btrfs_super_block *sb,
3250                             int do_barriers, int wait, int max_mirrors)
3251 {
3252         struct buffer_head *bh;
3253         int i;
3254         int ret;
3255         int errors = 0;
3256         u32 crc;
3257         u64 bytenr;
3258 
3259         if (max_mirrors == 0)
3260                 max_mirrors = BTRFS_SUPER_MIRROR_MAX;
3261 
3262         for (i = 0; i < max_mirrors; i++) {
3263                 bytenr = btrfs_sb_offset(i);
3264                 if (bytenr + BTRFS_SUPER_INFO_SIZE >=
3265                     device->commit_total_bytes)
3266                         break;
3267 
3268                 if (wait) {
3269                         bh = __find_get_block(device->bdev, bytenr / 4096,
3270                                               BTRFS_SUPER_INFO_SIZE);
3271                         if (!bh) {
3272                                 errors++;
3273                                 continue;
3274                         }
3275                         wait_on_buffer(bh);
3276                         if (!buffer_uptodate(bh))
3277                                 errors++;
3278 
3279                         /* drop our reference */
3280                         brelse(bh);
3281 
3282                         /* drop the reference from the wait == 0 run */
3283                         brelse(bh);
3284                         continue;
3285                 } else {
3286                         btrfs_set_super_bytenr(sb, bytenr);
3287 
3288                         crc = ~(u32)0;
3289                         crc = btrfs_csum_data((char *)sb +
3290                                               BTRFS_CSUM_SIZE, crc,
3291                                               BTRFS_SUPER_INFO_SIZE -
3292                                               BTRFS_CSUM_SIZE);
3293                         btrfs_csum_final(crc, sb->csum);
3294 
3295                         /*
3296                          * one reference for us, and we leave it for the
3297                          * caller
3298                          */
3299                         bh = __getblk(device->bdev, bytenr / 4096,
3300                                       BTRFS_SUPER_INFO_SIZE);
3301                         if (!bh) {
3302                                 printk(KERN_ERR "BTRFS: couldn't get super "
3303                                        "buffer head for bytenr %Lu\n", bytenr);
3304                                 errors++;
3305                                 continue;
3306                         }
3307 
3308                         memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
3309 
3310                         /* one reference for submit_bh */
3311                         get_bh(bh);
3312 
3313                         set_buffer_uptodate(bh);
3314                         lock_buffer(bh);
3315                         bh->b_end_io = btrfs_end_buffer_write_sync;
3316                         bh->b_private = device;
3317                 }
3318 
3319                 /*
3320                  * we fua the first super.  The others we allow
3321                  * to go down lazy.
3322                  */
3323                 if (i == 0)
3324                         ret = btrfsic_submit_bh(WRITE_FUA, bh);
3325                 else
3326                         ret = btrfsic_submit_bh(WRITE_SYNC, bh);
3327                 if (ret)
3328                         errors++;
3329         }
3330         return errors < i ? 0 : -1;
3331 }
3332 
3333 /*
3334  * endio for the write_dev_flush, this will wake anyone waiting
3335  * for the barrier when it is done
3336  */
3337 static void btrfs_end_empty_barrier(struct bio *bio)
3338 {
3339         if (bio->bi_private)
3340                 complete(bio->bi_private);
3341         bio_put(bio);
3342 }
3343 
3344 /*
3345  * trigger flushes for one the devices.  If you pass wait == 0, the flushes are
3346  * sent down.  With wait == 1, it waits for the previous flush.
3347  *
3348  * any device where the flush fails with eopnotsupp are flagged as not-barrier
3349  * capable
3350  */
3351 static int write_dev_flush(struct btrfs_device *device, int wait)
3352 {
3353         struct bio *bio;
3354         int ret = 0;
3355 
3356         if (device->nobarriers)
3357                 return 0;
3358 
3359         if (wait) {
3360                 bio = device->flush_bio;
3361                 if (!bio)
3362                         return 0;
3363 
3364                 wait_for_completion(&device->flush_wait);
3365 
3366                 if (bio->bi_error) {
3367                         ret = bio->bi_error;
3368                         btrfs_dev_stat_inc_and_print(device,
3369                                 BTRFS_DEV_STAT_FLUSH_ERRS);
3370                 }
3371 
3372                 /* drop the reference from the wait == 0 run */
3373                 bio_put(bio);
3374                 device->flush_bio = NULL;
3375 
3376                 return ret;
3377         }
3378 
3379         /*
3380          * one reference for us, and we leave it for the
3381          * caller
3382          */
3383         device->flush_bio = NULL;
3384         bio = btrfs_io_bio_alloc(GFP_NOFS, 0);
3385         if (!bio)
3386                 return -ENOMEM;
3387 
3388         bio->bi_end_io = btrfs_end_empty_barrier;
3389         bio->bi_bdev = device->bdev;
3390         init_completion(&device->flush_wait);
3391         bio->bi_private = &device->flush_wait;
3392         device->flush_bio = bio;
3393 
3394         bio_get(bio);
3395         btrfsic_submit_bio(WRITE_FLUSH, bio);
3396 
3397         return 0;
3398 }
3399 
3400 /*
3401  * send an empty flush down to each device in parallel,
3402  * then wait for them
3403  */
3404 static int barrier_all_devices(struct btrfs_fs_info *info)
3405 {
3406         struct list_head *head;
3407         struct btrfs_device *dev;
3408         int errors_send = 0;
3409         int errors_wait = 0;
3410         int ret;
3411 
3412         /* send down all the barriers */
3413         head = &info->fs_devices->devices;
3414         list_for_each_entry_rcu(dev, head, dev_list) {
3415                 if (dev->missing)
3416                         continue;
3417                 if (!dev->bdev) {
3418                         errors_send++;
3419                         continue;
3420                 }
3421                 if (!dev->in_fs_metadata || !dev->writeable)
3422                         continue;
3423 
3424                 ret = write_dev_flush(dev, 0);
3425                 if (ret)
3426                         errors_send++;
3427         }
3428 
3429         /* wait for all the barriers */
3430         list_for_each_entry_rcu(dev, head, dev_list) {
3431                 if (dev->missing)
3432                         continue;
3433                 if (!dev->bdev) {
3434                         errors_wait++;
3435                         continue;
3436                 }
3437                 if (!dev->in_fs_metadata || !dev->writeable)
3438                         continue;
3439 
3440                 ret = write_dev_flush(dev, 1);
3441                 if (ret)
3442                         errors_wait++;
3443         }
3444         if (errors_send > info->num_tolerated_disk_barrier_failures ||
3445             errors_wait > info->num_tolerated_disk_barrier_failures)
3446                 return -EIO;
3447         return 0;
3448 }
3449 
3450 int btrfs_get_num_tolerated_disk_barrier_failures(u64 flags)
3451 {
3452         if ((flags & (BTRFS_BLOCK_GROUP_DUP |
3453                       BTRFS_BLOCK_GROUP_RAID0 |
3454                       BTRFS_AVAIL_ALLOC_BIT_SINGLE)) ||
3455             ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0))
3456                 return 0;
3457 
3458         if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3459                      BTRFS_BLOCK_GROUP_RAID5 |
3460                      BTRFS_BLOCK_GROUP_RAID10))
3461                 return 1;
3462 
3463         if (flags & BTRFS_BLOCK_GROUP_RAID6)
3464                 return 2;
3465 
3466         pr_warn("BTRFS: unknown raid type: %llu\n", flags);
3467         return 0;
3468 }
3469 
3470 int btrfs_calc_num_tolerated_disk_barrier_failures(
3471         struct btrfs_fs_info *fs_info)
3472 {
3473         struct btrfs_ioctl_space_info space;
3474         struct btrfs_space_info *sinfo;
3475         u64 types[] = {BTRFS_BLOCK_GROUP_DATA,
3476                        BTRFS_BLOCK_GROUP_SYSTEM,
3477                        BTRFS_BLOCK_GROUP_METADATA,
3478                        BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA};
3479         int i;
3480         int c;
3481         int num_tolerated_disk_barrier_failures =
3482                 (int)fs_info->fs_devices->num_devices;
3483 
3484         for (i = 0; i < ARRAY_SIZE(types); i++) {
3485                 struct btrfs_space_info *tmp;
3486 
3487                 sinfo = NULL;
3488                 rcu_read_lock();
3489                 list_for_each_entry_rcu(tmp, &fs_info->space_info, list) {
3490                         if (tmp->flags == types[i]) {
3491                                 sinfo = tmp;
3492                                 break;
3493                         }
3494                 }
3495                 rcu_read_unlock();
3496 
3497                 if (!sinfo)
3498                         continue;
3499 
3500                 down_read(&sinfo->groups_sem);
3501                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
3502                         u64 flags;
3503 
3504                         if (list_empty(&sinfo->block_groups[c]))
3505                                 continue;
3506 
3507                         btrfs_get_block_group_info(&sinfo->block_groups[c],
3508                                                    &space);
3509                         if (space.total_bytes == 0 || space.used_bytes == 0)
3510                                 continue;
3511                         flags = space.flags;
3512 
3513                         num_tolerated_disk_barrier_failures = min(
3514                                 num_tolerated_disk_barrier_failures,
3515                                 btrfs_get_num_tolerated_disk_barrier_failures(
3516                                         flags));
3517                 }
3518                 up_read(&sinfo->groups_sem);
3519         }
3520 
3521         return num_tolerated_disk_barrier_failures;
3522 }
3523 
3524 static int write_all_supers(struct btrfs_root *root, int max_mirrors)
3525 {
3526         struct list_head *head;
3527         struct btrfs_device *dev;
3528         struct btrfs_super_block *sb;
3529         struct btrfs_dev_item *dev_item;
3530         int ret;
3531         int do_barriers;
3532         int max_errors;
3533         int total_errors = 0;
3534         u64 flags;
3535 
3536         do_barriers = !btrfs_test_opt(root, NOBARRIER);
3537         backup_super_roots(root->fs_info);
3538 
3539         sb = root->fs_info->super_for_commit;
3540         dev_item = &sb->dev_item;
3541 
3542         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
3543         head = &root->fs_info->fs_devices->devices;
3544         max_errors = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
3545 
3546         if (do_barriers) {
3547                 ret = barrier_all_devices(root->fs_info);
3548                 if (ret) {
3549                         mutex_unlock(
3550                                 &root->fs_info->fs_devices->device_list_mutex);
3551                         btrfs_error(root->fs_info, ret,
3552                                     "errors while submitting device barriers.");
3553                         return ret;
3554                 }
3555         }
3556 
3557         list_for_each_entry_rcu(dev, head, dev_list) {
3558                 if (!dev->bdev) {
3559                         total_errors++;
3560                         continue;
3561                 }
3562                 if (!dev->in_fs_metadata || !dev->writeable)
3563                         continue;
3564 
3565                 btrfs_set_stack_device_generation(dev_item, 0);
3566                 btrfs_set_stack_device_type(dev_item, dev->type);
3567                 btrfs_set_stack_device_id(dev_item, dev->devid);
3568                 btrfs_set_stack_device_total_bytes(dev_item,
3569                                                    dev->commit_total_bytes);
3570                 btrfs_set_stack_device_bytes_used(dev_item,
3571                                                   dev->commit_bytes_used);
3572                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
3573                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
3574                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
3575                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
3576                 memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
3577 
3578                 flags = btrfs_super_flags(sb);
3579                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
3580 
3581                 ret = write_dev_supers(dev, sb, do_barriers, 0, max_mirrors);
3582                 if (ret)
3583                         total_errors++;
3584         }
3585         if (total_errors > max_errors) {
3586                 btrfs_err(root->fs_info, "%d errors while writing supers",
3587                        total_errors);
3588                 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
3589 
3590                 /* FUA is masked off if unsupported and can't be the reason */
3591                 btrfs_error(root->fs_info, -EIO,
3592                             "%d errors while writing supers", total_errors);
3593                 return -EIO;
3594         }
3595 
3596         total_errors = 0;
3597         list_for_each_entry_rcu(dev, head, dev_list) {
3598                 if (!dev->bdev)
3599                         continue;
3600                 if (!dev->in_fs_metadata || !dev->writeable)
3601                         continue;
3602 
3603                 ret = write_dev_supers(dev, sb, do_barriers, 1, max_mirrors);
3604                 if (ret)
3605                         total_errors++;
3606         }
3607         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
3608         if (total_errors > max_errors) {
3609                 btrfs_error(root->fs_info, -EIO,
3610                             "%d errors while writing supers", total_errors);
3611                 return -EIO;
3612         }
3613         return 0;
3614 }
3615 
3616 int write_ctree_super(struct btrfs_trans_handle *trans,
3617                       struct btrfs_root *root, int max_mirrors)
3618 {
3619         return write_all_supers(root, max_mirrors);
3620 }
3621 
3622 /* Drop a fs root from the radix tree and free it. */
3623 void btrfs_drop_and_free_fs_root(struct btrfs_fs_info *fs_info,
3624                                   struct btrfs_root *root)
3625 {
3626         spin_lock(&fs_info->fs_roots_radix_lock);
3627         radix_tree_delete(&fs_info->fs_roots_radix,
3628                           (unsigned long)root->root_key.objectid);
3629         spin_unlock(&fs_info->fs_roots_radix_lock);
3630 
3631         if (btrfs_root_refs(&root->root_item) == 0)
3632                 synchronize_srcu(&fs_info->subvol_srcu);
3633 
3634         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
3635                 btrfs_free_log(NULL, root);
3636 
3637         if (root->free_ino_pinned)
3638                 __btrfs_remove_free_space_cache(root->free_ino_pinned);
3639         if (root->free_ino_ctl)
3640                 __btrfs_remove_free_space_cache(root->free_ino_ctl);
3641         free_fs_root(root);
3642 }
3643 
3644 static void free_fs_root(struct btrfs_root *root)
3645 {
3646         iput(root->ino_cache_inode);
3647         WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
3648         btrfs_free_block_rsv(root, root->orphan_block_rsv);
3649         root->orphan_block_rsv = NULL;
3650         if (root->anon_dev)
3651                 free_anon_bdev(root->anon_dev);
3652         if (root->subv_writers)
3653                 btrfs_free_subvolume_writers(root->subv_writers);
3654         free_extent_buffer(root->node);
3655         free_extent_buffer(root->commit_root);
3656         kfree(root->free_ino_ctl);
3657         kfree(root->free_ino_pinned);
3658         kfree(root->name);
3659         btrfs_put_fs_root(root);
3660 }
3661 
3662 void btrfs_free_fs_root(struct btrfs_root *root)
3663 {
3664         free_fs_root(root);
3665 }
3666 
3667 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
3668 {
3669         u64 root_objectid = 0;
3670         struct btrfs_root *gang[8];
3671         int i = 0;
3672         int err = 0;
3673         unsigned int ret = 0;
3674         int index;
3675 
3676         while (1) {
3677                 index = srcu_read_lock(&fs_info->subvol_srcu);
3678                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
3679                                              (void **)gang, root_objectid,
3680                                              ARRAY_SIZE(gang));
3681                 if (!ret) {
3682                         srcu_read_unlock(&fs_info->subvol_srcu, index);
3683                         break;
3684                 }
3685                 root_objectid = gang[ret - 1]->root_key.objectid + 1;
3686 
3687                 for (i = 0; i < ret; i++) {
3688                         /* Avoid to grab roots in dead_roots */
3689                         if (btrfs_root_refs(&gang[i]->root_item) == 0) {
3690                                 gang[i] = NULL;
3691                                 continue;
3692                         }
3693                         /* grab all the search result for later use */
3694                         gang[i] = btrfs_grab_fs_root(gang[i]);
3695                 }
3696                 srcu_read_unlock(&fs_info->subvol_srcu, index);
3697 
3698                 for (i = 0; i < ret; i++) {
3699                         if (!gang[i])
3700                                 continue;
3701                         root_objectid = gang[i]->root_key.objectid;
3702                         err = btrfs_orphan_cleanup(gang[i]);
3703                         if (err)
3704                                 break;
3705                         btrfs_put_fs_root(gang[i]);
3706                 }
3707                 root_objectid++;
3708         }
3709 
3710         /* release the uncleaned roots due to error */
3711         for (; i < ret; i++) {
3712                 if (gang[i])
3713                         btrfs_put_fs_root(gang[i]);
3714         }
3715         return err;
3716 }
3717 
3718 int btrfs_commit_super(struct btrfs_root *root)
3719 {
3720         struct btrfs_trans_handle *trans;
3721 
3722         mutex_lock(&root->fs_info->cleaner_mutex);
3723         btrfs_run_delayed_iputs(root);
3724         mutex_unlock(&root->fs_info->cleaner_mutex);
3725         wake_up_process(root->fs_info->cleaner_kthread);
3726 
3727         /* wait until ongoing cleanup work done */
3728         down_write(&root->fs_info->cleanup_work_sem);
3729         up_write(&root->fs_info->cleanup_work_sem);
3730 
3731         trans = btrfs_join_transaction(root);
3732         if (IS_ERR(trans))
3733                 return PTR_ERR(trans);
3734         return btrfs_commit_transaction(trans, root);
3735 }
3736 
3737 void close_ctree(struct btrfs_root *root)
3738 {
3739         struct btrfs_fs_info *fs_info = root->fs_info;
3740         int ret;
3741 
3742         fs_info->closing = 1;
3743         smp_mb();
3744 
3745         /* wait for the uuid_scan task to finish */
3746         down(&fs_info->uuid_tree_rescan_sem);
3747         /* avoid complains from lockdep et al., set sem back to initial state */
3748         up(&fs_info->uuid_tree_rescan_sem);
3749 
3750         /* pause restriper - we want to resume on mount */
3751         btrfs_pause_balance(fs_info);
3752 
3753         btrfs_dev_replace_suspend_for_unmount(fs_info);
3754 
3755         btrfs_scrub_cancel(fs_info);
3756 
3757         /* wait for any defraggers to finish */
3758         wait_event(fs_info->transaction_wait,
3759                    (atomic_read(&fs_info->defrag_running) == 0));
3760 
3761         /* clear out the rbtree of defraggable inodes */
3762         btrfs_cleanup_defrag_inodes(fs_info);
3763 
3764         cancel_work_sync(&fs_info->async_reclaim_work);
3765 
3766         if (!(fs_info->sb->s_flags & MS_RDONLY)) {
3767                 /*
3768                  * If the cleaner thread is stopped and there are
3769                  * block groups queued for removal, the deletion will be
3770                  * skipped when we quit the cleaner thread.
3771                  */
3772                 btrfs_delete_unused_bgs(root->fs_info);
3773 
3774                 ret = btrfs_commit_super(root);
3775                 if (ret)
3776                         btrfs_err(fs_info, "commit super ret %d", ret);
3777         }
3778 
3779         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
3780                 btrfs_error_commit_super(root);
3781 
3782         kthread_stop(fs_info->transaction_kthread);
3783         kthread_stop(fs_info->cleaner_kthread);
3784 
3785         fs_info->closing = 2;
3786         smp_mb();
3787 
3788         btrfs_free_qgroup_config(fs_info);
3789 
3790         if (percpu_counter_sum(&fs_info->delalloc_bytes)) {
3791                 btrfs_info(fs_info, "at unmount delalloc count %lld",
3792                        percpu_counter_sum(&fs_info->delalloc_bytes));
3793         }
3794 
3795         btrfs_sysfs_remove_one(fs_info);
3796         btrfs_sysfs_remove_fsid(fs_info->fs_devices);
3797 
3798         btrfs_free_fs_roots(fs_info);
3799 
3800         btrfs_put_block_group_cache(fs_info);
3801 
3802         btrfs_free_block_groups(fs_info);
3803 
3804         /*
3805          * we must make sure there is not any read request to
3806          * submit after we stopping all workers.
3807          */
3808         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
3809         btrfs_stop_all_workers(fs_info);
3810 
3811         fs_info->open = 0;
3812         free_root_pointers(fs_info, 1);
3813 
3814         iput(fs_info->btree_inode);
3815 
3816 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
3817         if (btrfs_test_opt(root, CHECK_INTEGRITY))
3818                 btrfsic_unmount(root, fs_info->fs_devices);
3819 #endif
3820 
3821         btrfs_close_devices(fs_info->fs_devices);
3822         btrfs_mapping_tree_free(&fs_info->mapping_tree);
3823 
3824         percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
3825         percpu_counter_destroy(&fs_info->delalloc_bytes);
3826         percpu_counter_destroy(&fs_info->bio_counter);
3827         bdi_destroy(&fs_info->bdi);
3828         cleanup_srcu_struct(&fs_info->subvol_srcu);
3829 
3830         btrfs_free_stripe_hash_table(fs_info);
3831 
3832         __btrfs_free_block_rsv(root->orphan_block_rsv);
3833         root->orphan_block_rsv = NULL;
3834 
3835         lock_chunks(root);
3836         while (!list_empty(&fs_info->pinned_chunks)) {
3837                 struct extent_map *em;
3838 
3839                 em = list_first_entry(&fs_info->pinned_chunks,
3840                                       struct extent_map, list);
3841                 list_del_init(&em->list);
3842                 free_extent_map(em);
3843         }
3844         unlock_chunks(root);
3845 }
3846 
3847 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
3848                           int atomic)
3849 {
3850         int ret;
3851         struct inode *btree_inode = buf->pages[0]->mapping->host;
3852 
3853         ret = extent_buffer_uptodate(buf);
3854         if (!ret)
3855                 return ret;
3856 
3857         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
3858                                     parent_transid, atomic);
3859         if (ret == -EAGAIN)
3860                 return ret;
3861         return !ret;
3862 }
3863 
3864 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
3865 {
3866         return set_extent_buffer_uptodate(buf);
3867 }
3868 
3869 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
3870 {
3871         struct btrfs_root *root;
3872         u64 transid = btrfs_header_generation(buf);
3873         int was_dirty;
3874 
3875 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3876         /*
3877          * This is a fast path so only do this check if we have sanity tests
3878          * enabled.  Normal people shouldn't be marking dummy buffers as dirty
3879          * outside of the sanity tests.
3880          */
3881         if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &buf->bflags)))
3882                 return;
3883 #endif
3884         root = BTRFS_I(buf->pages[0]->mapping->host)->root;
3885         btrfs_assert_tree_locked(buf);
3886         if (transid != root->fs_info->generation)
3887                 WARN(1, KERN_CRIT "btrfs transid mismatch buffer %llu, "
3888                        "found %llu running %llu\n",
3889                         buf->start, transid, root->fs_info->generation);
3890         was_dirty = set_extent_buffer_dirty(buf);
3891         if (!was_dirty)
3892                 __percpu_counter_add(&root->fs_info->dirty_metadata_bytes,
3893                                      buf->len,
3894                                      root->fs_info->dirty_metadata_batch);
3895 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
3896         if (btrfs_header_level(buf) == 0 && check_leaf(root, buf)) {
3897                 btrfs_print_leaf(root, buf);
3898                 ASSERT(0);
3899         }
3900 #endif
3901 }
3902 
3903 static void __btrfs_btree_balance_dirty(struct btrfs_root *root,
3904                                         int flush_delayed)
3905 {
3906         /*
3907          * looks as though older kernels can get into trouble with
3908          * this code, they end up stuck in balance_dirty_pages forever
3909          */
3910         int ret;
3911 
3912         if (current->flags & PF_MEMALLOC)
3913                 return;
3914 
3915         if (flush_delayed)
3916                 btrfs_balance_delayed_items(root);
3917 
3918         ret = percpu_counter_compare(&root->fs_info->dirty_metadata_bytes,
3919                                      BTRFS_DIRTY_METADATA_THRESH);
3920         if (ret > 0) {
3921                 balance_dirty_pages_ratelimited(
3922                                    root->fs_info->btree_inode->i_mapping);
3923         }
3924         return;
3925 }
3926 
3927 void btrfs_btree_balance_dirty(struct btrfs_root *root)
3928 {
3929         __btrfs_btree_balance_dirty(root, 1);
3930 }
3931 
3932 void btrfs_btree_balance_dirty_nodelay(struct btrfs_root *root)
3933 {
3934         __btrfs_btree_balance_dirty(root, 0);
3935 }
3936 
3937 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
3938 {
3939         struct btrfs_root *root = BTRFS_I(buf->pages[0]->mapping->host)->root;
3940         return btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
3941 }
3942 
3943 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
3944                               int read_only)
3945 {
3946         struct btrfs_super_block *sb = fs_info->super_copy;
3947         int ret = 0;
3948 
3949         if (btrfs_super_root_level(sb) >= BTRFS_MAX_LEVEL) {
3950                 printk(KERN_ERR "BTRFS: tree_root level too big: %d >= %d\n",
3951                                 btrfs_super_root_level(sb), BTRFS_MAX_LEVEL);
3952                 ret = -EINVAL;
3953         }
3954         if (btrfs_super_chunk_root_level(sb) >= BTRFS_MAX_LEVEL) {
3955                 printk(KERN_ERR "BTRFS: chunk_root level too big: %d >= %d\n",
3956                                 btrfs_super_chunk_root_level(sb), BTRFS_MAX_LEVEL);
3957                 ret = -EINVAL;
3958         }
3959         if (btrfs_super_log_root_level(sb) >= BTRFS_MAX_LEVEL) {
3960                 printk(KERN_ERR "BTRFS: log_root level too big: %d >= %d\n",
3961                                 btrfs_super_log_root_level(sb), BTRFS_MAX_LEVEL);
3962                 ret = -EINVAL;
3963         }
3964 
3965         /*
3966          * The common minimum, we don't know if we can trust the nodesize/sectorsize
3967          * items yet, they'll be verified later. Issue just a warning.
3968          */
3969         if (!IS_ALIGNED(btrfs_super_root(sb), 4096))
3970                 printk(KERN_WARNING "BTRFS: tree_root block unaligned: %llu\n",
3971                                 btrfs_super_root(sb));
3972         if (!IS_ALIGNED(btrfs_super_chunk_root(sb), 4096))
3973                 printk(KERN_WARNING "BTRFS: chunk_root block unaligned: %llu\n",
3974                                 btrfs_super_chunk_root(sb));
3975         if (!IS_ALIGNED(btrfs_super_log_root(sb), 4096))
3976                 printk(KERN_WARNING "BTRFS: log_root block unaligned: %llu\n",
3977                                 btrfs_super_log_root(sb));
3978 
3979         /*
3980          * Check the lower bound, the alignment and other constraints are
3981          * checked later.
3982          */
3983         if (btrfs_super_nodesize(sb) < 4096) {
3984                 printk(KERN_ERR "BTRFS: nodesize too small: %u < 4096\n",
3985                                 btrfs_super_nodesize(sb));
3986                 ret = -EINVAL;
3987         }
3988         if (btrfs_super_sectorsize(sb) < 4096) {
3989                 printk(KERN_ERR "BTRFS: sectorsize too small: %u < 4096\n",
3990                                 btrfs_super_sectorsize(sb));
3991                 ret = -EINVAL;
3992         }
3993 
3994         if (memcmp(fs_info->fsid, sb->dev_item.fsid, BTRFS_UUID_SIZE) != 0) {
3995                 printk(KERN_ERR "BTRFS: dev_item UUID does not match fsid: %pU != %pU\n",
3996                                 fs_info->fsid, sb->dev_item.fsid);
3997                 ret = -EINVAL;
3998         }
3999 
4000         /*
4001          * Hint to catch really bogus numbers, bitflips or so, more exact checks are
4002          * done later
4003          */
4004         if (btrfs_super_num_devices(sb) > (1UL << 31))
4005                 printk(KERN_WARNING "BTRFS: suspicious number of devices: %llu\n",
4006                                 btrfs_super_num_devices(sb));
4007         if (btrfs_super_num_devices(sb) == 0) {
4008                 printk(KERN_ERR "BTRFS: number of devices is 0\n");
4009                 ret = -EINVAL;
4010         }
4011 
4012         if (btrfs_super_bytenr(sb) != BTRFS_SUPER_INFO_OFFSET) {
4013                 printk(KERN_ERR "BTRFS: super offset mismatch %llu != %u\n",
4014                                 btrfs_super_bytenr(sb), BTRFS_SUPER_INFO_OFFSET);
4015                 ret = -EINVAL;
4016         }
4017 
4018         /*
4019          * Obvious sys_chunk_array corruptions, it must hold at least one key
4020          * and one chunk
4021          */
4022         if (btrfs_super_sys_array_size(sb) > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
4023                 printk(KERN_ERR "BTRFS: system chunk array too big %u > %u\n",
4024                                 btrfs_super_sys_array_size(sb),
4025                                 BTRFS_SYSTEM_CHUNK_ARRAY_SIZE);
4026                 ret = -EINVAL;
4027         }
4028         if (btrfs_super_sys_array_size(sb) < sizeof(struct btrfs_disk_key)
4029                         + sizeof(struct btrfs_chunk)) {
4030                 printk(KERN_ERR "BTRFS: system chunk array too small %u < %zu\n",
4031                                 btrfs_super_sys_array_size(sb),
4032                                 sizeof(struct btrfs_disk_key)
4033                                 + sizeof(struct btrfs_chunk));
4034                 ret = -EINVAL;
4035         }
4036 
4037         /*
4038          * The generation is a global counter, we'll trust it more than the others
4039          * but it's still possible that it's the one that's wrong.
4040          */
4041         if (btrfs_super_generation(sb) < btrfs_super_chunk_root_generation(sb))
4042                 printk(KERN_WARNING
4043                         "BTRFS: suspicious: generation < chunk_root_generation: %llu < %llu\n",
4044                         btrfs_super_generation(sb), btrfs_super_chunk_root_generation(sb));
4045         if (btrfs_super_generation(sb) < btrfs_super_cache_generation(sb)
4046             && btrfs_super_cache_generation(sb) != (u64)-1)
4047                 printk(KERN_WARNING
4048                         "BTRFS: suspicious: generation < cache_generation: %llu < %llu\n",
4049                         btrfs_super_generation(sb), btrfs_super_cache_generation(sb));
4050 
4051         return ret;
4052 }
4053 
4054 static void btrfs_error_commit_super(struct btrfs_root *root)
4055 {
4056         mutex_lock(&root->fs_info->cleaner_mutex);
4057         btrfs_run_delayed_iputs(root);
4058         mutex_unlock(&root->fs_info->cleaner_mutex);
4059 
4060         down_write(&root->fs_info->cleanup_work_sem);
4061         up_write(&root->fs_info->cleanup_work_sem);
4062 
4063         /* cleanup FS via transaction */
4064         btrfs_cleanup_transaction(root);
4065 }
4066 
4067 static void btrfs_destroy_ordered_extents(struct btrfs_root *root)
4068 {
4069         struct btrfs_ordered_extent *ordered;
4070 
4071         spin_lock(&root->ordered_extent_lock);
4072         /*
4073          * This will just short circuit the ordered completion stuff which will
4074          * make sure the ordered extent gets properly cleaned up.
4075          */
4076         list_for_each_entry(ordered, &root->ordered_extents,
4077                             root_extent_list)
4078                 set_bit(BTRFS_ORDERED_IOERR, &ordered->flags);
4079         spin_unlock(&root->ordered_extent_lock);
4080 }
4081 
4082 static void btrfs_destroy_all_ordered_extents(struct btrfs_fs_info *fs_info)
4083 {
4084         struct btrfs_root *root;
4085         struct list_head splice;
4086 
4087         INIT_LIST_HEAD(&splice);
4088 
4089         spin_lock(&fs_info->ordered_root_lock);
4090         list_splice_init(&fs_info->ordered_roots, &splice);
4091         while (!list_empty(&splice)) {
4092                 root = list_first_entry(&splice, struct btrfs_root,
4093                                         ordered_root);
4094                 list_move_tail(&root->ordered_root,
4095                                &fs_info->ordered_roots);
4096 
4097                 spin_unlock(&fs_info->ordered_root_lock);
4098                 btrfs_destroy_ordered_extents(root);
4099 
4100                 cond_resched();
4101                 spin_lock(&fs_info->ordered_root_lock);
4102         }
4103         spin_unlock(&fs_info->ordered_root_lock);
4104 }
4105 
4106 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
4107                                       struct btrfs_root *root)
4108 {
4109         struct rb_node *node;
4110         struct btrfs_delayed_ref_root *delayed_refs;
4111         struct btrfs_delayed_ref_node *ref;
4112         int ret = 0;
4113 
4114         delayed_refs = &trans->delayed_refs;
4115 
4116         spin_lock(&delayed_refs->lock);
4117         if (atomic_read(&delayed_refs->num_entries) == 0) {
4118                 spin_unlock(&delayed_refs->lock);
4119                 btrfs_info(root->fs_info, "delayed_refs has NO entry");
4120                 return ret;
4121         }
4122 
4123         while ((node = rb_first(&delayed_refs->href_root)) != NULL) {
4124                 struct btrfs_delayed_ref_head *head;
4125                 struct btrfs_delayed_ref_node *tmp;
4126                 bool pin_bytes = false;
4127 
4128                 head = rb_entry(node, struct btrfs_delayed_ref_head,
4129                                 href_node);
4130                 if (!mutex_trylock(&head->mutex)) {
4131                         atomic_inc(&head->node.refs);
4132                         spin_unlock(&delayed_refs->lock);
4133 
4134                         mutex_lock(&head->mutex);
4135                         mutex_unlock(&head->mutex);
4136                         btrfs_put_delayed_ref(&head->node);
4137                         spin_lock(&delayed_refs->lock);
4138                         continue;
4139                 }
4140                 spin_lock(&head->lock);
4141                 list_for_each_entry_safe_reverse(ref, tmp, &head->ref_list,
4142                                                  list) {
4143                         ref->in_tree = 0;
4144                         list_del(&ref->list);
4145                         atomic_dec(&delayed_refs->num_entries);
4146                         btrfs_put_delayed_ref(ref);
4147                 }
4148                 if (head->must_insert_reserved)
4149                         pin_bytes = true;
4150                 btrfs_free_delayed_extent_op(head->extent_op);
4151                 delayed_refs->num_heads--;
4152                 if (head->processing == 0)
4153                         delayed_refs->num_heads_ready--;
4154                 atomic_dec(&delayed_refs->num_entries);
4155                 head->node.in_tree = 0;
4156                 rb_erase(&head->href_node, &delayed_refs->href_root);
4157                 spin_unlock(&head->lock);
4158                 spin_unlock(&delayed_refs->lock);
4159                 mutex_unlock(&head->mutex);
4160 
4161                 if (pin_bytes)
4162                         btrfs_pin_extent(root, head->node.bytenr,
4163                                          head->node.num_bytes, 1);
4164                 btrfs_put_delayed_ref(&head->node);
4165                 cond_resched();
4166                 spin_lock(&delayed_refs->lock);
4167         }
4168 
4169         spin_unlock(&delayed_refs->lock);
4170 
4171         return ret;
4172 }
4173 
4174 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
4175 {
4176         struct btrfs_inode *btrfs_inode;
4177         struct list_head splice;
4178 
4179         INIT_LIST_HEAD(&splice);
4180 
4181         spin_lock(&root->delalloc_lock);
4182         list_splice_init(&root->delalloc_inodes, &splice);
4183 
4184         while (!list_empty(&splice)) {
4185                 btrfs_inode = list_first_entry(&splice, struct btrfs_inode,
4186                                                delalloc_inodes);
4187 
4188                 list_del_init(&btrfs_inode->delalloc_inodes);
4189                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
4190                           &btrfs_inode->runtime_flags);
4191                 spin_unlock(&root->delalloc_lock);
4192 
4193                 btrfs_invalidate_inodes(btrfs_inode->root);
4194 
4195                 spin_lock(&root->delalloc_lock);
4196         }
4197 
4198         spin_unlock(&root->delalloc_lock);
4199 }
4200 
4201 static void btrfs_destroy_all_delalloc_inodes(struct btrfs_fs_info *fs_info)
4202 {
4203         struct btrfs_root *root;
4204         struct list_head splice;
4205 
4206         INIT_LIST_HEAD(&splice);
4207 
4208         spin_lock(&fs_info->delalloc_root_lock);
4209         list_splice_init(&fs_info->delalloc_roots, &splice);
4210         while (!list_empty(&splice)) {
4211                 root = list_first_entry(&splice, struct btrfs_root,
4212                                          delalloc_root);
4213                 list_del_init(&root->delalloc_root);
4214                 root = btrfs_grab_fs_root(root);
4215                 BUG_ON(!root);
4216                 spin_unlock(&fs_info->delalloc_root_lock);
4217 
4218                 btrfs_destroy_delalloc_inodes(root);
4219                 btrfs_put_fs_root(root);
4220 
4221                 spin_lock(&fs_info->delalloc_root_lock);
4222         }
4223         spin_unlock(&fs_info->delalloc_root_lock);
4224 }
4225 
4226 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
4227                                         struct extent_io_tree *dirty_pages,
4228                                         int mark)
4229 {
4230         int ret;
4231         struct extent_buffer *eb;
4232         u64 start = 0;
4233         u64 end;
4234 
4235         while (1) {
4236                 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
4237                                             mark, NULL);
4238                 if (ret)
4239                         break;
4240 
4241                 clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
4242                 while (start <= end) {
4243                         eb = btrfs_find_tree_block(root->fs_info, start);
4244                         start += root->nodesize;
4245                         if (!eb)
4246                                 continue;
4247                         wait_on_extent_buffer_writeback(eb);
4248 
4249                         if (test_and_clear_bit(EXTENT_BUFFER_DIRTY,
4250                                                &eb->bflags))
4251                                 clear_extent_buffer_dirty(eb);
4252                         free_extent_buffer_stale(eb);
4253                 }
4254         }
4255 
4256         return ret;
4257 }
4258 
4259 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
4260                                        struct extent_io_tree *pinned_extents)
4261 {
4262         struct extent_io_tree *unpin;
4263         u64 start;
4264         u64 end;
4265         int ret;
4266         bool loop = true;
4267 
4268         unpin = pinned_extents;
4269 again:
4270         while (1) {
4271                 ret = find_first_extent_bit(unpin, 0, &start, &end,
4272                                             EXTENT_DIRTY, NULL);
4273                 if (ret)
4274                         break;
4275 
4276                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
4277                 btrfs_error_unpin_extent_range(root, start, end);
4278                 cond_resched();
4279         }
4280 
4281         if (loop) {
4282                 if (unpin == &root->fs_info->freed_extents[0])
4283                         unpin = &root->fs_info->freed_extents[1];
4284                 else
4285                         unpin = &root->fs_info->freed_extents[0];
4286                 loop = false;
4287                 goto again;
4288         }
4289 
4290         return 0;
4291 }
4292 
4293 static void btrfs_free_pending_ordered(struct btrfs_transaction *cur_trans,
4294                                        struct btrfs_fs_info *fs_info)
4295 {
4296         struct btrfs_ordered_extent *ordered;
4297 
4298         spin_lock(&fs_info->trans_lock);
4299         while (!list_empty(&cur_trans->pending_ordered)) {
4300                 ordered = list_first_entry(&cur_trans->pending_ordered,
4301                                            struct btrfs_ordered_extent,
4302                                            trans_list);
4303                 list_del_init(&ordered->trans_list);
4304                 spin_unlock(&fs_info->trans_lock);
4305 
4306                 btrfs_put_ordered_extent(ordered);
4307                 spin_lock(&fs_info->trans_lock);
4308         }
4309         spin_unlock(&fs_info->trans_lock);
4310 }
4311 
4312 void btrfs_cleanup_one_transaction(struct btrfs_transaction *cur_trans,
4313                                    struct btrfs_root *root)
4314 {
4315         btrfs_destroy_delayed_refs(cur_trans, root);
4316 
4317         cur_trans->state = TRANS_STATE_COMMIT_START;
4318         wake_up(&root->fs_info->transaction_blocked_wait);
4319 
4320         cur_trans->state = TRANS_STATE_UNBLOCKED;
4321         wake_up(&root->fs_info->transaction_wait);
4322 
4323         btrfs_free_pending_ordered(cur_trans, root->fs_info);
4324         btrfs_destroy_delayed_inodes(root);
4325         btrfs_assert_delayed_root_empty(root);
4326 
4327         btrfs_destroy_marked_extents(root, &cur_trans->dirty_pages,
4328                                      EXTENT_DIRTY);
4329         btrfs_destroy_pinned_extent(root,
4330                                     root->fs_info->pinned_extents);
4331 
4332         cur_trans->state =TRANS_STATE_COMPLETED;
4333         wake_up(&cur_trans->commit_wait);
4334 
4335         /*
4336         memset(cur_trans, 0, sizeof(*cur_trans));
4337         kmem_cache_free(btrfs_transaction_cachep, cur_trans);
4338         */
4339 }
4340 
4341 static int btrfs_cleanup_transaction(struct btrfs_root *root)
4342 {
4343         struct btrfs_transaction *t;
4344 
4345         mutex_lock(&root->fs_info->transaction_kthread_mutex);
4346 
4347         spin_lock(&root->fs_info->trans_lock);
4348         while (!list_empty(&root->fs_info->trans_list)) {
4349                 t = list_first_entry(&root->fs_info->trans_list,
4350                                      struct btrfs_transaction, list);
4351                 if (t->state >= TRANS_STATE_COMMIT_START) {
4352                         atomic_inc(&t->use_count);
4353                         spin_unlock(&root->fs_info->trans_lock);
4354                         btrfs_wait_for_commit(root, t->transid);
4355                         btrfs_put_transaction(t);
4356                         spin_lock(&root->fs_info->trans_lock);
4357                         continue;
4358                 }
4359                 if (t == root->fs_info->running_transaction) {
4360                         t->state = TRANS_STATE_COMMIT_DOING;
4361                         spin_unlock(&root->fs_info->trans_lock);
4362                         /*
4363                          * We wait for 0 num_writers since we don't hold a trans
4364                          * handle open currently for this transaction.
4365                          */
4366                         wait_event(t->writer_wait,
4367                                    atomic_read(&t->num_writers) == 0);
4368                 } else {
4369                         spin_unlock(&root->fs_info->trans_lock);
4370                 }
4371                 btrfs_cleanup_one_transaction(t, root);
4372 
4373                 spin_lock(&root->fs_info->trans_lock);
4374                 if (t == root->fs_info->running_transaction)
4375                         root->fs_info->running_transaction = NULL;
4376                 list_del_init(&t->list);
4377                 spin_unlock(&root->fs_info->trans_lock);
4378 
4379                 btrfs_put_transaction(t);
4380                 trace_btrfs_transaction_commit(root);
4381                 spin_lock(&root->fs_info->trans_lock);
4382         }
4383         spin_unlock(&root->fs_info->trans_lock);
4384         btrfs_destroy_all_ordered_extents(root->fs_info);
4385         btrfs_destroy_delayed_inodes(root);
4386         btrfs_assert_delayed_root_empty(root);
4387         btrfs_destroy_pinned_extent(root, root->fs_info->pinned_extents);
4388         btrfs_destroy_all_delalloc_inodes(root->fs_info);
4389         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
4390 
4391         return 0;
4392 }
4393 
4394 static const struct extent_io_ops btree_extent_io_ops = {
4395         .readpage_end_io_hook = btree_readpage_end_io_hook,
4396         .readpage_io_failed_hook = btree_io_failed_hook,
4397         .submit_bio_hook = btree_submit_bio_hook,
4398         /* note we're sharing with inode.c for the merge bio hook */
4399         .merge_bio_hook = btrfs_merge_bio_hook,
4400 };
4401 

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