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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/crc32c.h>
 30 #include <linux/slab.h>
 31 #include <linux/migrate.h>
 32 #include <linux/ratelimit.h>
 33 #include <linux/uuid.h>
 34 #include <asm/unaligned.h>
 35 #include "compat.h"
 36 #include "ctree.h"
 37 #include "disk-io.h"
 38 #include "transaction.h"
 39 #include "btrfs_inode.h"
 40 #include "volumes.h"
 41 #include "print-tree.h"
 42 #include "async-thread.h"
 43 #include "locking.h"
 44 #include "tree-log.h"
 45 #include "free-space-cache.h"
 46 #include "inode-map.h"
 47 #include "check-integrity.h"
 48 #include "rcu-string.h"
 49 #include "dev-replace.h"
 50 #include "raid56.h"
 51 
 52 #ifdef CONFIG_X86
 53 #include <asm/cpufeature.h>
 54 #endif
 55 
 56 static struct extent_io_ops btree_extent_io_ops;
 57 static void end_workqueue_fn(struct btrfs_work *work);
 58 static void free_fs_root(struct btrfs_root *root);
 59 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
 60                                     int read_only);
 61 static void btrfs_destroy_ordered_operations(struct btrfs_transaction *t,
 62                                              struct btrfs_root *root);
 63 static void btrfs_destroy_ordered_extents(struct btrfs_root *root);
 64 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
 65                                       struct btrfs_root *root);
 66 static void btrfs_evict_pending_snapshots(struct btrfs_transaction *t);
 67 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root);
 68 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
 69                                         struct extent_io_tree *dirty_pages,
 70                                         int mark);
 71 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
 72                                        struct extent_io_tree *pinned_extents);
 73 static int btrfs_cleanup_transaction(struct btrfs_root *root);
 74 static void btrfs_error_commit_super(struct btrfs_root *root);
 75 
 76 /*
 77  * end_io_wq structs are used to do processing in task context when an IO is
 78  * complete.  This is used during reads to verify checksums, and it is used
 79  * by writes to insert metadata for new file extents after IO is complete.
 80  */
 81 struct end_io_wq {
 82         struct bio *bio;
 83         bio_end_io_t *end_io;
 84         void *private;
 85         struct btrfs_fs_info *info;
 86         int error;
 87         int metadata;
 88         struct list_head list;
 89         struct btrfs_work work;
 90 };
 91 
 92 /*
 93  * async submit bios are used to offload expensive checksumming
 94  * onto the worker threads.  They checksum file and metadata bios
 95  * just before they are sent down the IO stack.
 96  */
 97 struct async_submit_bio {
 98         struct inode *inode;
 99         struct bio *bio;
100         struct list_head list;
101         extent_submit_bio_hook_t *submit_bio_start;
102         extent_submit_bio_hook_t *submit_bio_done;
103         int rw;
104         int mirror_num;
105         unsigned long bio_flags;
106         /*
107          * bio_offset is optional, can be used if the pages in the bio
108          * can't tell us where in the file the bio should go
109          */
110         u64 bio_offset;
111         struct btrfs_work work;
112         int error;
113 };
114 
115 /*
116  * Lockdep class keys for extent_buffer->lock's in this root.  For a given
117  * eb, the lockdep key is determined by the btrfs_root it belongs to and
118  * the level the eb occupies in the tree.
119  *
120  * Different roots are used for different purposes and may nest inside each
121  * other and they require separate keysets.  As lockdep keys should be
122  * static, assign keysets according to the purpose of the root as indicated
123  * by btrfs_root->objectid.  This ensures that all special purpose roots
124  * have separate keysets.
125  *
126  * Lock-nesting across peer nodes is always done with the immediate parent
127  * node locked thus preventing deadlock.  As lockdep doesn't know this, use
128  * subclass to avoid triggering lockdep warning in such cases.
129  *
130  * The key is set by the readpage_end_io_hook after the buffer has passed
131  * csum validation but before the pages are unlocked.  It is also set by
132  * btrfs_init_new_buffer on freshly allocated blocks.
133  *
134  * We also add a check to make sure the highest level of the tree is the
135  * same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this code
136  * needs update as well.
137  */
138 #ifdef CONFIG_DEBUG_LOCK_ALLOC
139 # if BTRFS_MAX_LEVEL != 8
140 #  error
141 # endif
142 
143 static struct btrfs_lockdep_keyset {
144         u64                     id;             /* root objectid */
145         const char              *name_stem;     /* lock name stem */
146         char                    names[BTRFS_MAX_LEVEL + 1][20];
147         struct lock_class_key   keys[BTRFS_MAX_LEVEL + 1];
148 } btrfs_lockdep_keysets[] = {
149         { .id = BTRFS_ROOT_TREE_OBJECTID,       .name_stem = "root"     },
150         { .id = BTRFS_EXTENT_TREE_OBJECTID,     .name_stem = "extent"   },
151         { .id = BTRFS_CHUNK_TREE_OBJECTID,      .name_stem = "chunk"    },
152         { .id = BTRFS_DEV_TREE_OBJECTID,        .name_stem = "dev"      },
153         { .id = BTRFS_FS_TREE_OBJECTID,         .name_stem = "fs"       },
154         { .id = BTRFS_CSUM_TREE_OBJECTID,       .name_stem = "csum"     },
155         { .id = BTRFS_QUOTA_TREE_OBJECTID,      .name_stem = "quota"    },
156         { .id = BTRFS_TREE_LOG_OBJECTID,        .name_stem = "log"      },
157         { .id = BTRFS_TREE_RELOC_OBJECTID,      .name_stem = "treloc"   },
158         { .id = BTRFS_DATA_RELOC_TREE_OBJECTID, .name_stem = "dreloc"   },
159         { .id = 0,                              .name_stem = "tree"     },
160 };
161 
162 void __init btrfs_init_lockdep(void)
163 {
164         int i, j;
165 
166         /* initialize lockdep class names */
167         for (i = 0; i < ARRAY_SIZE(btrfs_lockdep_keysets); i++) {
168                 struct btrfs_lockdep_keyset *ks = &btrfs_lockdep_keysets[i];
169 
170                 for (j = 0; j < ARRAY_SIZE(ks->names); j++)
171                         snprintf(ks->names[j], sizeof(ks->names[j]),
172                                  "btrfs-%s-%02d", ks->name_stem, j);
173         }
174 }
175 
176 void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb,
177                                     int level)
178 {
179         struct btrfs_lockdep_keyset *ks;
180 
181         BUG_ON(level >= ARRAY_SIZE(ks->keys));
182 
183         /* find the matching keyset, id 0 is the default entry */
184         for (ks = btrfs_lockdep_keysets; ks->id; ks++)
185                 if (ks->id == objectid)
186                         break;
187 
188         lockdep_set_class_and_name(&eb->lock,
189                                    &ks->keys[level], ks->names[level]);
190 }
191 
192 #endif
193 
194 /*
195  * extents on the btree inode are pretty simple, there's one extent
196  * that covers the entire device
197  */
198 static struct extent_map *btree_get_extent(struct inode *inode,
199                 struct page *page, size_t pg_offset, u64 start, u64 len,
200                 int create)
201 {
202         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
203         struct extent_map *em;
204         int ret;
205 
206         read_lock(&em_tree->lock);
207         em = lookup_extent_mapping(em_tree, start, len);
208         if (em) {
209                 em->bdev =
210                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
211                 read_unlock(&em_tree->lock);
212                 goto out;
213         }
214         read_unlock(&em_tree->lock);
215 
216         em = alloc_extent_map();
217         if (!em) {
218                 em = ERR_PTR(-ENOMEM);
219                 goto out;
220         }
221         em->start = 0;
222         em->len = (u64)-1;
223         em->block_len = (u64)-1;
224         em->block_start = 0;
225         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
226 
227         write_lock(&em_tree->lock);
228         ret = add_extent_mapping(em_tree, em, 0);
229         if (ret == -EEXIST) {
230                 free_extent_map(em);
231                 em = lookup_extent_mapping(em_tree, start, len);
232                 if (!em)
233                         em = ERR_PTR(-EIO);
234         } else if (ret) {
235                 free_extent_map(em);
236                 em = ERR_PTR(ret);
237         }
238         write_unlock(&em_tree->lock);
239 
240 out:
241         return em;
242 }
243 
244 u32 btrfs_csum_data(char *data, u32 seed, size_t len)
245 {
246         return crc32c(seed, data, len);
247 }
248 
249 void btrfs_csum_final(u32 crc, char *result)
250 {
251         put_unaligned_le32(~crc, result);
252 }
253 
254 /*
255  * compute the csum for a btree block, and either verify it or write it
256  * into the csum field of the block.
257  */
258 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
259                            int verify)
260 {
261         u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
262         char *result = NULL;
263         unsigned long len;
264         unsigned long cur_len;
265         unsigned long offset = BTRFS_CSUM_SIZE;
266         char *kaddr;
267         unsigned long map_start;
268         unsigned long map_len;
269         int err;
270         u32 crc = ~(u32)0;
271         unsigned long inline_result;
272 
273         len = buf->len - offset;
274         while (len > 0) {
275                 err = map_private_extent_buffer(buf, offset, 32,
276                                         &kaddr, &map_start, &map_len);
277                 if (err)
278                         return 1;
279                 cur_len = min(len, map_len - (offset - map_start));
280                 crc = btrfs_csum_data(kaddr + offset - map_start,
281                                       crc, cur_len);
282                 len -= cur_len;
283                 offset += cur_len;
284         }
285         if (csum_size > sizeof(inline_result)) {
286                 result = kzalloc(csum_size * sizeof(char), GFP_NOFS);
287                 if (!result)
288                         return 1;
289         } else {
290                 result = (char *)&inline_result;
291         }
292 
293         btrfs_csum_final(crc, result);
294 
295         if (verify) {
296                 if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
297                         u32 val;
298                         u32 found = 0;
299                         memcpy(&found, result, csum_size);
300 
301                         read_extent_buffer(buf, &val, 0, csum_size);
302                         printk_ratelimited(KERN_INFO "btrfs: %s checksum verify "
303                                        "failed on %llu wanted %X found %X "
304                                        "level %d\n",
305                                        root->fs_info->sb->s_id,
306                                        (unsigned long long)buf->start, val, found,
307                                        btrfs_header_level(buf));
308                         if (result != (char *)&inline_result)
309                                 kfree(result);
310                         return 1;
311                 }
312         } else {
313                 write_extent_buffer(buf, result, 0, csum_size);
314         }
315         if (result != (char *)&inline_result)
316                 kfree(result);
317         return 0;
318 }
319 
320 /*
321  * we can't consider a given block up to date unless the transid of the
322  * block matches the transid in the parent node's pointer.  This is how we
323  * detect blocks that either didn't get written at all or got written
324  * in the wrong place.
325  */
326 static int verify_parent_transid(struct extent_io_tree *io_tree,
327                                  struct extent_buffer *eb, u64 parent_transid,
328                                  int atomic)
329 {
330         struct extent_state *cached_state = NULL;
331         int ret;
332 
333         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
334                 return 0;
335 
336         if (atomic)
337                 return -EAGAIN;
338 
339         lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
340                          0, &cached_state);
341         if (extent_buffer_uptodate(eb) &&
342             btrfs_header_generation(eb) == parent_transid) {
343                 ret = 0;
344                 goto out;
345         }
346         printk_ratelimited("parent transid verify failed on %llu wanted %llu "
347                        "found %llu\n",
348                        (unsigned long long)eb->start,
349                        (unsigned long long)parent_transid,
350                        (unsigned long long)btrfs_header_generation(eb));
351         ret = 1;
352         clear_extent_buffer_uptodate(eb);
353 out:
354         unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
355                              &cached_state, GFP_NOFS);
356         return ret;
357 }
358 
359 /*
360  * Return 0 if the superblock checksum type matches the checksum value of that
361  * algorithm. Pass the raw disk superblock data.
362  */
363 static int btrfs_check_super_csum(char *raw_disk_sb)
364 {
365         struct btrfs_super_block *disk_sb =
366                 (struct btrfs_super_block *)raw_disk_sb;
367         u16 csum_type = btrfs_super_csum_type(disk_sb);
368         int ret = 0;
369 
370         if (csum_type == BTRFS_CSUM_TYPE_CRC32) {
371                 u32 crc = ~(u32)0;
372                 const int csum_size = sizeof(crc);
373                 char result[csum_size];
374 
375                 /*
376                  * The super_block structure does not span the whole
377                  * BTRFS_SUPER_INFO_SIZE range, we expect that the unused space
378                  * is filled with zeros and is included in the checkum.
379                  */
380                 crc = btrfs_csum_data(raw_disk_sb + BTRFS_CSUM_SIZE,
381                                 crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
382                 btrfs_csum_final(crc, result);
383 
384                 if (memcmp(raw_disk_sb, result, csum_size))
385                         ret = 1;
386 
387                 if (ret && btrfs_super_generation(disk_sb) < 10) {
388                         printk(KERN_WARNING "btrfs: super block crcs don't match, older mkfs detected\n");
389                         ret = 0;
390                 }
391         }
392 
393         if (csum_type >= ARRAY_SIZE(btrfs_csum_sizes)) {
394                 printk(KERN_ERR "btrfs: unsupported checksum algorithm %u\n",
395                                 csum_type);
396                 ret = 1;
397         }
398 
399         return ret;
400 }
401 
402 /*
403  * helper to read a given tree block, doing retries as required when
404  * the checksums don't match and we have alternate mirrors to try.
405  */
406 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
407                                           struct extent_buffer *eb,
408                                           u64 start, u64 parent_transid)
409 {
410         struct extent_io_tree *io_tree;
411         int failed = 0;
412         int ret;
413         int num_copies = 0;
414         int mirror_num = 0;
415         int failed_mirror = 0;
416 
417         clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
418         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
419         while (1) {
420                 ret = read_extent_buffer_pages(io_tree, eb, start,
421                                                WAIT_COMPLETE,
422                                                btree_get_extent, mirror_num);
423                 if (!ret) {
424                         if (!verify_parent_transid(io_tree, eb,
425                                                    parent_transid, 0))
426                                 break;
427                         else
428                                 ret = -EIO;
429                 }
430 
431                 /*
432                  * This buffer's crc is fine, but its contents are corrupted, so
433                  * there is no reason to read the other copies, they won't be
434                  * any less wrong.
435                  */
436                 if (test_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags))
437                         break;
438 
439                 num_copies = btrfs_num_copies(root->fs_info,
440                                               eb->start, eb->len);
441                 if (num_copies == 1)
442                         break;
443 
444                 if (!failed_mirror) {
445                         failed = 1;
446                         failed_mirror = eb->read_mirror;
447                 }
448 
449                 mirror_num++;
450                 if (mirror_num == failed_mirror)
451                         mirror_num++;
452 
453                 if (mirror_num > num_copies)
454                         break;
455         }
456 
457         if (failed && !ret && failed_mirror)
458                 repair_eb_io_failure(root, eb, failed_mirror);
459 
460         return ret;
461 }
462 
463 /*
464  * checksum a dirty tree block before IO.  This has extra checks to make sure
465  * we only fill in the checksum field in the first page of a multi-page block
466  */
467 
468 static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
469 {
470         struct extent_io_tree *tree;
471         u64 start = page_offset(page);
472         u64 found_start;
473         struct extent_buffer *eb;
474 
475         tree = &BTRFS_I(page->mapping->host)->io_tree;
476 
477         eb = (struct extent_buffer *)page->private;
478         if (page != eb->pages[0])
479                 return 0;
480         found_start = btrfs_header_bytenr(eb);
481         if (found_start != start) {
482                 WARN_ON(1);
483                 return 0;
484         }
485         if (!PageUptodate(page)) {
486                 WARN_ON(1);
487                 return 0;
488         }
489         csum_tree_block(root, eb, 0);
490         return 0;
491 }
492 
493 static int check_tree_block_fsid(struct btrfs_root *root,
494                                  struct extent_buffer *eb)
495 {
496         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
497         u8 fsid[BTRFS_UUID_SIZE];
498         int ret = 1;
499 
500         read_extent_buffer(eb, fsid, (unsigned long)btrfs_header_fsid(eb),
501                            BTRFS_FSID_SIZE);
502         while (fs_devices) {
503                 if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
504                         ret = 0;
505                         break;
506                 }
507                 fs_devices = fs_devices->seed;
508         }
509         return ret;
510 }
511 
512 #define CORRUPT(reason, eb, root, slot)                         \
513         printk(KERN_CRIT "btrfs: corrupt leaf, %s: block=%llu," \
514                "root=%llu, slot=%d\n", reason,                  \
515                (unsigned long long)btrfs_header_bytenr(eb),     \
516                (unsigned long long)root->objectid, slot)
517 
518 static noinline int check_leaf(struct btrfs_root *root,
519                                struct extent_buffer *leaf)
520 {
521         struct btrfs_key key;
522         struct btrfs_key leaf_key;
523         u32 nritems = btrfs_header_nritems(leaf);
524         int slot;
525 
526         if (nritems == 0)
527                 return 0;
528 
529         /* Check the 0 item */
530         if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=
531             BTRFS_LEAF_DATA_SIZE(root)) {
532                 CORRUPT("invalid item offset size pair", leaf, root, 0);
533                 return -EIO;
534         }
535 
536         /*
537          * Check to make sure each items keys are in the correct order and their
538          * offsets make sense.  We only have to loop through nritems-1 because
539          * we check the current slot against the next slot, which verifies the
540          * next slot's offset+size makes sense and that the current's slot
541          * offset is correct.
542          */
543         for (slot = 0; slot < nritems - 1; slot++) {
544                 btrfs_item_key_to_cpu(leaf, &leaf_key, slot);
545                 btrfs_item_key_to_cpu(leaf, &key, slot + 1);
546 
547                 /* Make sure the keys are in the right order */
548                 if (btrfs_comp_cpu_keys(&leaf_key, &key) >= 0) {
549                         CORRUPT("bad key order", leaf, root, slot);
550                         return -EIO;
551                 }
552 
553                 /*
554                  * Make sure the offset and ends are right, remember that the
555                  * item data starts at the end of the leaf and grows towards the
556                  * front.
557                  */
558                 if (btrfs_item_offset_nr(leaf, slot) !=
559                         btrfs_item_end_nr(leaf, slot + 1)) {
560                         CORRUPT("slot offset bad", leaf, root, slot);
561                         return -EIO;
562                 }
563 
564                 /*
565                  * Check to make sure that we don't point outside of the leaf,
566                  * just incase all the items are consistent to eachother, but
567                  * all point outside of the leaf.
568                  */
569                 if (btrfs_item_end_nr(leaf, slot) >
570                     BTRFS_LEAF_DATA_SIZE(root)) {
571                         CORRUPT("slot end outside of leaf", leaf, root, slot);
572                         return -EIO;
573                 }
574         }
575 
576         return 0;
577 }
578 
579 static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
580                                struct extent_state *state, int mirror)
581 {
582         struct extent_io_tree *tree;
583         u64 found_start;
584         int found_level;
585         struct extent_buffer *eb;
586         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
587         int ret = 0;
588         int reads_done;
589 
590         if (!page->private)
591                 goto out;
592 
593         tree = &BTRFS_I(page->mapping->host)->io_tree;
594         eb = (struct extent_buffer *)page->private;
595 
596         /* the pending IO might have been the only thing that kept this buffer
597          * in memory.  Make sure we have a ref for all this other checks
598          */
599         extent_buffer_get(eb);
600 
601         reads_done = atomic_dec_and_test(&eb->io_pages);
602         if (!reads_done)
603                 goto err;
604 
605         eb->read_mirror = mirror;
606         if (test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) {
607                 ret = -EIO;
608                 goto err;
609         }
610 
611         found_start = btrfs_header_bytenr(eb);
612         if (found_start != eb->start) {
613                 printk_ratelimited(KERN_INFO "btrfs bad tree block start "
614                                "%llu %llu\n",
615                                (unsigned long long)found_start,
616                                (unsigned long long)eb->start);
617                 ret = -EIO;
618                 goto err;
619         }
620         if (check_tree_block_fsid(root, eb)) {
621                 printk_ratelimited(KERN_INFO "btrfs bad fsid on block %llu\n",
622                                (unsigned long long)eb->start);
623                 ret = -EIO;
624                 goto err;
625         }
626         found_level = btrfs_header_level(eb);
627         if (found_level >= BTRFS_MAX_LEVEL) {
628                 btrfs_info(root->fs_info, "bad tree block level %d\n",
629                            (int)btrfs_header_level(eb));
630                 ret = -EIO;
631                 goto err;
632         }
633 
634         btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb),
635                                        eb, found_level);
636 
637         ret = csum_tree_block(root, eb, 1);
638         if (ret) {
639                 ret = -EIO;
640                 goto err;
641         }
642 
643         /*
644          * If this is a leaf block and it is corrupt, set the corrupt bit so
645          * that we don't try and read the other copies of this block, just
646          * return -EIO.
647          */
648         if (found_level == 0 && check_leaf(root, eb)) {
649                 set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
650                 ret = -EIO;
651         }
652 
653         if (!ret)
654                 set_extent_buffer_uptodate(eb);
655 err:
656         if (reads_done &&
657             test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
658                 btree_readahead_hook(root, eb, eb->start, ret);
659 
660         if (ret) {
661                 /*
662                  * our io error hook is going to dec the io pages
663                  * again, we have to make sure it has something
664                  * to decrement
665                  */
666                 atomic_inc(&eb->io_pages);
667                 clear_extent_buffer_uptodate(eb);
668         }
669         free_extent_buffer(eb);
670 out:
671         return ret;
672 }
673 
674 static int btree_io_failed_hook(struct page *page, int failed_mirror)
675 {
676         struct extent_buffer *eb;
677         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
678 
679         eb = (struct extent_buffer *)page->private;
680         set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
681         eb->read_mirror = failed_mirror;
682         atomic_dec(&eb->io_pages);
683         if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
684                 btree_readahead_hook(root, eb, eb->start, -EIO);
685         return -EIO;    /* we fixed nothing */
686 }
687 
688 static void end_workqueue_bio(struct bio *bio, int err)
689 {
690         struct end_io_wq *end_io_wq = bio->bi_private;
691         struct btrfs_fs_info *fs_info;
692 
693         fs_info = end_io_wq->info;
694         end_io_wq->error = err;
695         end_io_wq->work.func = end_workqueue_fn;
696         end_io_wq->work.flags = 0;
697 
698         if (bio->bi_rw & REQ_WRITE) {
699                 if (end_io_wq->metadata == BTRFS_WQ_ENDIO_METADATA)
700                         btrfs_queue_worker(&fs_info->endio_meta_write_workers,
701                                            &end_io_wq->work);
702                 else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_FREE_SPACE)
703                         btrfs_queue_worker(&fs_info->endio_freespace_worker,
704                                            &end_io_wq->work);
705                 else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56)
706                         btrfs_queue_worker(&fs_info->endio_raid56_workers,
707                                            &end_io_wq->work);
708                 else
709                         btrfs_queue_worker(&fs_info->endio_write_workers,
710                                            &end_io_wq->work);
711         } else {
712                 if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56)
713                         btrfs_queue_worker(&fs_info->endio_raid56_workers,
714                                            &end_io_wq->work);
715                 else if (end_io_wq->metadata)
716                         btrfs_queue_worker(&fs_info->endio_meta_workers,
717                                            &end_io_wq->work);
718                 else
719                         btrfs_queue_worker(&fs_info->endio_workers,
720                                            &end_io_wq->work);
721         }
722 }
723 
724 /*
725  * For the metadata arg you want
726  *
727  * 0 - if data
728  * 1 - if normal metadta
729  * 2 - if writing to the free space cache area
730  * 3 - raid parity work
731  */
732 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
733                         int metadata)
734 {
735         struct end_io_wq *end_io_wq;
736         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
737         if (!end_io_wq)
738                 return -ENOMEM;
739 
740         end_io_wq->private = bio->bi_private;
741         end_io_wq->end_io = bio->bi_end_io;
742         end_io_wq->info = info;
743         end_io_wq->error = 0;
744         end_io_wq->bio = bio;
745         end_io_wq->metadata = metadata;
746 
747         bio->bi_private = end_io_wq;
748         bio->bi_end_io = end_workqueue_bio;
749         return 0;
750 }
751 
752 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
753 {
754         unsigned long limit = min_t(unsigned long,
755                                     info->workers.max_workers,
756                                     info->fs_devices->open_devices);
757         return 256 * limit;
758 }
759 
760 static void run_one_async_start(struct btrfs_work *work)
761 {
762         struct async_submit_bio *async;
763         int ret;
764 
765         async = container_of(work, struct  async_submit_bio, work);
766         ret = async->submit_bio_start(async->inode, async->rw, async->bio,
767                                       async->mirror_num, async->bio_flags,
768                                       async->bio_offset);
769         if (ret)
770                 async->error = ret;
771 }
772 
773 static void run_one_async_done(struct btrfs_work *work)
774 {
775         struct btrfs_fs_info *fs_info;
776         struct async_submit_bio *async;
777         int limit;
778 
779         async = container_of(work, struct  async_submit_bio, work);
780         fs_info = BTRFS_I(async->inode)->root->fs_info;
781 
782         limit = btrfs_async_submit_limit(fs_info);
783         limit = limit * 2 / 3;
784 
785         if (atomic_dec_return(&fs_info->nr_async_submits) < limit &&
786             waitqueue_active(&fs_info->async_submit_wait))
787                 wake_up(&fs_info->async_submit_wait);
788 
789         /* If an error occured we just want to clean up the bio and move on */
790         if (async->error) {
791                 bio_endio(async->bio, async->error);
792                 return;
793         }
794 
795         async->submit_bio_done(async->inode, async->rw, async->bio,
796                                async->mirror_num, async->bio_flags,
797                                async->bio_offset);
798 }
799 
800 static void run_one_async_free(struct btrfs_work *work)
801 {
802         struct async_submit_bio *async;
803 
804         async = container_of(work, struct  async_submit_bio, work);
805         kfree(async);
806 }
807 
808 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
809                         int rw, struct bio *bio, int mirror_num,
810                         unsigned long bio_flags,
811                         u64 bio_offset,
812                         extent_submit_bio_hook_t *submit_bio_start,
813                         extent_submit_bio_hook_t *submit_bio_done)
814 {
815         struct async_submit_bio *async;
816 
817         async = kmalloc(sizeof(*async), GFP_NOFS);
818         if (!async)
819                 return -ENOMEM;
820 
821         async->inode = inode;
822         async->rw = rw;
823         async->bio = bio;
824         async->mirror_num = mirror_num;
825         async->submit_bio_start = submit_bio_start;
826         async->submit_bio_done = submit_bio_done;
827 
828         async->work.func = run_one_async_start;
829         async->work.ordered_func = run_one_async_done;
830         async->work.ordered_free = run_one_async_free;
831 
832         async->work.flags = 0;
833         async->bio_flags = bio_flags;
834         async->bio_offset = bio_offset;
835 
836         async->error = 0;
837 
838         atomic_inc(&fs_info->nr_async_submits);
839 
840         if (rw & REQ_SYNC)
841                 btrfs_set_work_high_prio(&async->work);
842 
843         btrfs_queue_worker(&fs_info->workers, &async->work);
844 
845         while (atomic_read(&fs_info->async_submit_draining) &&
846               atomic_read(&fs_info->nr_async_submits)) {
847                 wait_event(fs_info->async_submit_wait,
848                            (atomic_read(&fs_info->nr_async_submits) == 0));
849         }
850 
851         return 0;
852 }
853 
854 static int btree_csum_one_bio(struct bio *bio)
855 {
856         struct bio_vec *bvec = bio->bi_io_vec;
857         int bio_index = 0;
858         struct btrfs_root *root;
859         int ret = 0;
860 
861         WARN_ON(bio->bi_vcnt <= 0);
862         while (bio_index < bio->bi_vcnt) {
863                 root = BTRFS_I(bvec->bv_page->mapping->host)->root;
864                 ret = csum_dirty_buffer(root, bvec->bv_page);
865                 if (ret)
866                         break;
867                 bio_index++;
868                 bvec++;
869         }
870         return ret;
871 }
872 
873 static int __btree_submit_bio_start(struct inode *inode, int rw,
874                                     struct bio *bio, int mirror_num,
875                                     unsigned long bio_flags,
876                                     u64 bio_offset)
877 {
878         /*
879          * when we're called for a write, we're already in the async
880          * submission context.  Just jump into btrfs_map_bio
881          */
882         return btree_csum_one_bio(bio);
883 }
884 
885 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
886                                  int mirror_num, unsigned long bio_flags,
887                                  u64 bio_offset)
888 {
889         int ret;
890 
891         /*
892          * when we're called for a write, we're already in the async
893          * submission context.  Just jump into btrfs_map_bio
894          */
895         ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
896         if (ret)
897                 bio_endio(bio, ret);
898         return ret;
899 }
900 
901 static int check_async_write(struct inode *inode, unsigned long bio_flags)
902 {
903         if (bio_flags & EXTENT_BIO_TREE_LOG)
904                 return 0;
905 #ifdef CONFIG_X86
906         if (cpu_has_xmm4_2)
907                 return 0;
908 #endif
909         return 1;
910 }
911 
912 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
913                                  int mirror_num, unsigned long bio_flags,
914                                  u64 bio_offset)
915 {
916         int async = check_async_write(inode, bio_flags);
917         int ret;
918 
919         if (!(rw & REQ_WRITE)) {
920                 /*
921                  * called for a read, do the setup so that checksum validation
922                  * can happen in the async kernel threads
923                  */
924                 ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
925                                           bio, 1);
926                 if (ret)
927                         goto out_w_error;
928                 ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
929                                     mirror_num, 0);
930         } else if (!async) {
931                 ret = btree_csum_one_bio(bio);
932                 if (ret)
933                         goto out_w_error;
934                 ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
935                                     mirror_num, 0);
936         } else {
937                 /*
938                  * kthread helpers are used to submit writes so that
939                  * checksumming can happen in parallel across all CPUs
940                  */
941                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
942                                           inode, rw, bio, mirror_num, 0,
943                                           bio_offset,
944                                           __btree_submit_bio_start,
945                                           __btree_submit_bio_done);
946         }
947 
948         if (ret) {
949 out_w_error:
950                 bio_endio(bio, ret);
951         }
952         return ret;
953 }
954 
955 #ifdef CONFIG_MIGRATION
956 static int btree_migratepage(struct address_space *mapping,
957                         struct page *newpage, struct page *page,
958                         enum migrate_mode mode)
959 {
960         /*
961          * we can't safely write a btree page from here,
962          * we haven't done the locking hook
963          */
964         if (PageDirty(page))
965                 return -EAGAIN;
966         /*
967          * Buffers may be managed in a filesystem specific way.
968          * We must have no buffers or drop them.
969          */
970         if (page_has_private(page) &&
971             !try_to_release_page(page, GFP_KERNEL))
972                 return -EAGAIN;
973         return migrate_page(mapping, newpage, page, mode);
974 }
975 #endif
976 
977 
978 static int btree_writepages(struct address_space *mapping,
979                             struct writeback_control *wbc)
980 {
981         struct extent_io_tree *tree;
982         struct btrfs_fs_info *fs_info;
983         int ret;
984 
985         tree = &BTRFS_I(mapping->host)->io_tree;
986         if (wbc->sync_mode == WB_SYNC_NONE) {
987 
988                 if (wbc->for_kupdate)
989                         return 0;
990 
991                 fs_info = BTRFS_I(mapping->host)->root->fs_info;
992                 /* this is a bit racy, but that's ok */
993                 ret = percpu_counter_compare(&fs_info->dirty_metadata_bytes,
994                                              BTRFS_DIRTY_METADATA_THRESH);
995                 if (ret < 0)
996                         return 0;
997         }
998         return btree_write_cache_pages(mapping, wbc);
999 }
1000 
1001 static int btree_readpage(struct file *file, struct page *page)
1002 {
1003         struct extent_io_tree *tree;
1004         tree = &BTRFS_I(page->mapping->host)->io_tree;
1005         return extent_read_full_page(tree, page, btree_get_extent, 0);
1006 }
1007 
1008 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
1009 {
1010         if (PageWriteback(page) || PageDirty(page))
1011                 return 0;
1012 
1013         return try_release_extent_buffer(page);
1014 }
1015 
1016 static void btree_invalidatepage(struct page *page, unsigned int offset,
1017                                  unsigned int length)
1018 {
1019         struct extent_io_tree *tree;
1020         tree = &BTRFS_I(page->mapping->host)->io_tree;
1021         extent_invalidatepage(tree, page, offset);
1022         btree_releasepage(page, GFP_NOFS);
1023         if (PagePrivate(page)) {
1024                 printk(KERN_WARNING "btrfs warning page private not zero "
1025                        "on page %llu\n", (unsigned long long)page_offset(page));
1026                 ClearPagePrivate(page);
1027                 set_page_private(page, 0);
1028                 page_cache_release(page);
1029         }
1030 }
1031 
1032 static int btree_set_page_dirty(struct page *page)
1033 {
1034 #ifdef DEBUG
1035         struct extent_buffer *eb;
1036 
1037         BUG_ON(!PagePrivate(page));
1038         eb = (struct extent_buffer *)page->private;
1039         BUG_ON(!eb);
1040         BUG_ON(!test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
1041         BUG_ON(!atomic_read(&eb->refs));
1042         btrfs_assert_tree_locked(eb);
1043 #endif
1044         return __set_page_dirty_nobuffers(page);
1045 }
1046 
1047 static const struct address_space_operations btree_aops = {
1048         .readpage       = btree_readpage,
1049         .writepages     = btree_writepages,
1050         .releasepage    = btree_releasepage,
1051         .invalidatepage = btree_invalidatepage,
1052 #ifdef CONFIG_MIGRATION
1053         .migratepage    = btree_migratepage,
1054 #endif
1055         .set_page_dirty = btree_set_page_dirty,
1056 };
1057 
1058 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
1059                          u64 parent_transid)
1060 {
1061         struct extent_buffer *buf = NULL;
1062         struct inode *btree_inode = root->fs_info->btree_inode;
1063         int ret = 0;
1064 
1065         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1066         if (!buf)
1067                 return 0;
1068         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
1069                                  buf, 0, WAIT_NONE, btree_get_extent, 0);
1070         free_extent_buffer(buf);
1071         return ret;
1072 }
1073 
1074 int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr, u32 blocksize,
1075                          int mirror_num, struct extent_buffer **eb)
1076 {
1077         struct extent_buffer *buf = NULL;
1078         struct inode *btree_inode = root->fs_info->btree_inode;
1079         struct extent_io_tree *io_tree = &BTRFS_I(btree_inode)->io_tree;
1080         int ret;
1081 
1082         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1083         if (!buf)
1084                 return 0;
1085 
1086         set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
1087 
1088         ret = read_extent_buffer_pages(io_tree, buf, 0, WAIT_PAGE_LOCK,
1089                                        btree_get_extent, mirror_num);
1090         if (ret) {
1091                 free_extent_buffer(buf);
1092                 return ret;
1093         }
1094 
1095         if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags)) {
1096                 free_extent_buffer(buf);
1097                 return -EIO;
1098         } else if (extent_buffer_uptodate(buf)) {
1099                 *eb = buf;
1100         } else {
1101                 free_extent_buffer(buf);
1102         }
1103         return 0;
1104 }
1105 
1106 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
1107                                             u64 bytenr, u32 blocksize)
1108 {
1109         struct inode *btree_inode = root->fs_info->btree_inode;
1110         struct extent_buffer *eb;
1111         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
1112                                 bytenr, blocksize);
1113         return eb;
1114 }
1115 
1116 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
1117                                                  u64 bytenr, u32 blocksize)
1118 {
1119         struct inode *btree_inode = root->fs_info->btree_inode;
1120         struct extent_buffer *eb;
1121 
1122         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
1123                                  bytenr, blocksize);
1124         return eb;
1125 }
1126 
1127 
1128 int btrfs_write_tree_block(struct extent_buffer *buf)
1129 {
1130         return filemap_fdatawrite_range(buf->pages[0]->mapping, buf->start,
1131                                         buf->start + buf->len - 1);
1132 }
1133 
1134 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
1135 {
1136         return filemap_fdatawait_range(buf->pages[0]->mapping,
1137                                        buf->start, buf->start + buf->len - 1);
1138 }
1139 
1140 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
1141                                       u32 blocksize, u64 parent_transid)
1142 {
1143         struct extent_buffer *buf = NULL;
1144         int ret;
1145 
1146         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1147         if (!buf)
1148                 return NULL;
1149 
1150         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
1151         return buf;
1152 
1153 }
1154 
1155 void clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1156                       struct extent_buffer *buf)
1157 {
1158         struct btrfs_fs_info *fs_info = root->fs_info;
1159 
1160         if (btrfs_header_generation(buf) ==
1161             fs_info->running_transaction->transid) {
1162                 btrfs_assert_tree_locked(buf);
1163 
1164                 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
1165                         __percpu_counter_add(&fs_info->dirty_metadata_bytes,
1166                                              -buf->len,
1167                                              fs_info->dirty_metadata_batch);
1168                         /* ugh, clear_extent_buffer_dirty needs to lock the page */
1169                         btrfs_set_lock_blocking(buf);
1170                         clear_extent_buffer_dirty(buf);
1171                 }
1172         }
1173 }
1174 
1175 static void __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
1176                          u32 stripesize, struct btrfs_root *root,
1177                          struct btrfs_fs_info *fs_info,
1178                          u64 objectid)
1179 {
1180         root->node = NULL;
1181         root->commit_root = NULL;
1182         root->sectorsize = sectorsize;
1183         root->nodesize = nodesize;
1184         root->leafsize = leafsize;
1185         root->stripesize = stripesize;
1186         root->ref_cows = 0;
1187         root->track_dirty = 0;
1188         root->in_radix = 0;
1189         root->orphan_item_inserted = 0;
1190         root->orphan_cleanup_state = 0;
1191 
1192         root->objectid = objectid;
1193         root->last_trans = 0;
1194         root->highest_objectid = 0;
1195         root->nr_delalloc_inodes = 0;
1196         root->nr_ordered_extents = 0;
1197         root->name = NULL;
1198         root->inode_tree = RB_ROOT;
1199         INIT_RADIX_TREE(&root->delayed_nodes_tree, GFP_ATOMIC);
1200         root->block_rsv = NULL;
1201         root->orphan_block_rsv = NULL;
1202 
1203         INIT_LIST_HEAD(&root->dirty_list);
1204         INIT_LIST_HEAD(&root->root_list);
1205         INIT_LIST_HEAD(&root->delalloc_inodes);
1206         INIT_LIST_HEAD(&root->delalloc_root);
1207         INIT_LIST_HEAD(&root->ordered_extents);
1208         INIT_LIST_HEAD(&root->ordered_root);
1209         INIT_LIST_HEAD(&root->logged_list[0]);
1210         INIT_LIST_HEAD(&root->logged_list[1]);
1211         spin_lock_init(&root->orphan_lock);
1212         spin_lock_init(&root->inode_lock);
1213         spin_lock_init(&root->delalloc_lock);
1214         spin_lock_init(&root->ordered_extent_lock);
1215         spin_lock_init(&root->accounting_lock);
1216         spin_lock_init(&root->log_extents_lock[0]);
1217         spin_lock_init(&root->log_extents_lock[1]);
1218         mutex_init(&root->objectid_mutex);
1219         mutex_init(&root->log_mutex);
1220         init_waitqueue_head(&root->log_writer_wait);
1221         init_waitqueue_head(&root->log_commit_wait[0]);
1222         init_waitqueue_head(&root->log_commit_wait[1]);
1223         atomic_set(&root->log_commit[0], 0);
1224         atomic_set(&root->log_commit[1], 0);
1225         atomic_set(&root->log_writers, 0);
1226         atomic_set(&root->log_batch, 0);
1227         atomic_set(&root->orphan_inodes, 0);
1228         atomic_set(&root->refs, 1);
1229         root->log_transid = 0;
1230         root->last_log_commit = 0;
1231         extent_io_tree_init(&root->dirty_log_pages,
1232                              fs_info->btree_inode->i_mapping);
1233 
1234         memset(&root->root_key, 0, sizeof(root->root_key));
1235         memset(&root->root_item, 0, sizeof(root->root_item));
1236         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
1237         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
1238         root->defrag_trans_start = fs_info->generation;
1239         init_completion(&root->kobj_unregister);
1240         root->defrag_running = 0;
1241         root->root_key.objectid = objectid;
1242         root->anon_dev = 0;
1243 
1244         spin_lock_init(&root->root_item_lock);
1245 }
1246 
1247 static struct btrfs_root *btrfs_alloc_root(struct btrfs_fs_info *fs_info)
1248 {
1249         struct btrfs_root *root = kzalloc(sizeof(*root), GFP_NOFS);
1250         if (root)
1251                 root->fs_info = fs_info;
1252         return root;
1253 }
1254 
1255 struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
1256                                      struct btrfs_fs_info *fs_info,
1257                                      u64 objectid)
1258 {
1259         struct extent_buffer *leaf;
1260         struct btrfs_root *tree_root = fs_info->tree_root;
1261         struct btrfs_root *root;
1262         struct btrfs_key key;
1263         int ret = 0;
1264         u64 bytenr;
1265         uuid_le uuid;
1266 
1267         root = btrfs_alloc_root(fs_info);
1268         if (!root)
1269                 return ERR_PTR(-ENOMEM);
1270 
1271         __setup_root(tree_root->nodesize, tree_root->leafsize,
1272                      tree_root->sectorsize, tree_root->stripesize,
1273                      root, fs_info, objectid);
1274         root->root_key.objectid = objectid;
1275         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1276         root->root_key.offset = 0;
1277 
1278         leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
1279                                       0, objectid, NULL, 0, 0, 0);
1280         if (IS_ERR(leaf)) {
1281                 ret = PTR_ERR(leaf);
1282                 leaf = NULL;
1283                 goto fail;
1284         }
1285 
1286         bytenr = leaf->start;
1287         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1288         btrfs_set_header_bytenr(leaf, leaf->start);
1289         btrfs_set_header_generation(leaf, trans->transid);
1290         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1291         btrfs_set_header_owner(leaf, objectid);
1292         root->node = leaf;
1293 
1294         write_extent_buffer(leaf, fs_info->fsid,
1295                             (unsigned long)btrfs_header_fsid(leaf),
1296                             BTRFS_FSID_SIZE);
1297         write_extent_buffer(leaf, fs_info->chunk_tree_uuid,
1298                             (unsigned long)btrfs_header_chunk_tree_uuid(leaf),
1299                             BTRFS_UUID_SIZE);
1300         btrfs_mark_buffer_dirty(leaf);
1301 
1302         root->commit_root = btrfs_root_node(root);
1303         root->track_dirty = 1;
1304 
1305 
1306         root->root_item.flags = 0;
1307         root->root_item.byte_limit = 0;
1308         btrfs_set_root_bytenr(&root->root_item, leaf->start);
1309         btrfs_set_root_generation(&root->root_item, trans->transid);
1310         btrfs_set_root_level(&root->root_item, 0);
1311         btrfs_set_root_refs(&root->root_item, 1);
1312         btrfs_set_root_used(&root->root_item, leaf->len);
1313         btrfs_set_root_last_snapshot(&root->root_item, 0);
1314         btrfs_set_root_dirid(&root->root_item, 0);
1315         uuid_le_gen(&uuid);
1316         memcpy(root->root_item.uuid, uuid.b, BTRFS_UUID_SIZE);
1317         root->root_item.drop_level = 0;
1318 
1319         key.objectid = objectid;
1320         key.type = BTRFS_ROOT_ITEM_KEY;
1321         key.offset = 0;
1322         ret = btrfs_insert_root(trans, tree_root, &key, &root->root_item);
1323         if (ret)
1324                 goto fail;
1325 
1326         btrfs_tree_unlock(leaf);
1327 
1328         return root;
1329 
1330 fail:
1331         if (leaf) {
1332                 btrfs_tree_unlock(leaf);
1333                 free_extent_buffer(leaf);
1334         }
1335         kfree(root);
1336 
1337         return ERR_PTR(ret);
1338 }
1339 
1340 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1341                                          struct btrfs_fs_info *fs_info)
1342 {
1343         struct btrfs_root *root;
1344         struct btrfs_root *tree_root = fs_info->tree_root;
1345         struct extent_buffer *leaf;
1346 
1347         root = btrfs_alloc_root(fs_info);
1348         if (!root)
1349                 return ERR_PTR(-ENOMEM);
1350 
1351         __setup_root(tree_root->nodesize, tree_root->leafsize,
1352                      tree_root->sectorsize, tree_root->stripesize,
1353                      root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1354 
1355         root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1356         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1357         root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1358         /*
1359          * log trees do not get reference counted because they go away
1360          * before a real commit is actually done.  They do store pointers
1361          * to file data extents, and those reference counts still get
1362          * updated (along with back refs to the log tree).
1363          */
1364         root->ref_cows = 0;
1365 
1366         leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
1367                                       BTRFS_TREE_LOG_OBJECTID, NULL,
1368                                       0, 0, 0);
1369         if (IS_ERR(leaf)) {
1370                 kfree(root);
1371                 return ERR_CAST(leaf);
1372         }
1373 
1374         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1375         btrfs_set_header_bytenr(leaf, leaf->start);
1376         btrfs_set_header_generation(leaf, trans->transid);
1377         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1378         btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
1379         root->node = leaf;
1380 
1381         write_extent_buffer(root->node, root->fs_info->fsid,
1382                             (unsigned long)btrfs_header_fsid(root->node),
1383                             BTRFS_FSID_SIZE);
1384         btrfs_mark_buffer_dirty(root->node);
1385         btrfs_tree_unlock(root->node);
1386         return root;
1387 }
1388 
1389 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1390                              struct btrfs_fs_info *fs_info)
1391 {
1392         struct btrfs_root *log_root;
1393 
1394         log_root = alloc_log_tree(trans, fs_info);
1395         if (IS_ERR(log_root))
1396                 return PTR_ERR(log_root);
1397         WARN_ON(fs_info->log_root_tree);
1398         fs_info->log_root_tree = log_root;
1399         return 0;
1400 }
1401 
1402 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1403                        struct btrfs_root *root)
1404 {
1405         struct btrfs_root *log_root;
1406         struct btrfs_inode_item *inode_item;
1407 
1408         log_root = alloc_log_tree(trans, root->fs_info);
1409         if (IS_ERR(log_root))
1410                 return PTR_ERR(log_root);
1411 
1412         log_root->last_trans = trans->transid;
1413         log_root->root_key.offset = root->root_key.objectid;
1414 
1415         inode_item = &log_root->root_item.inode;
1416         inode_item->generation = cpu_to_le64(1);
1417         inode_item->size = cpu_to_le64(3);
1418         inode_item->nlink = cpu_to_le32(1);
1419         inode_item->nbytes = cpu_to_le64(root->leafsize);
1420         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
1421 
1422         btrfs_set_root_node(&log_root->root_item, log_root->node);
1423 
1424         WARN_ON(root->log_root);
1425         root->log_root = log_root;
1426         root->log_transid = 0;
1427         root->last_log_commit = 0;
1428         return 0;
1429 }
1430 
1431 struct btrfs_root *btrfs_read_tree_root(struct btrfs_root *tree_root,
1432                                         struct btrfs_key *key)
1433 {
1434         struct btrfs_root *root;
1435         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1436         struct btrfs_path *path;
1437         u64 generation;
1438         u32 blocksize;
1439         int ret;
1440 
1441         path = btrfs_alloc_path();
1442         if (!path)
1443                 return ERR_PTR(-ENOMEM);
1444 
1445         root = btrfs_alloc_root(fs_info);
1446         if (!root) {
1447                 ret = -ENOMEM;
1448                 goto alloc_fail;
1449         }
1450 
1451         __setup_root(tree_root->nodesize, tree_root->leafsize,
1452                      tree_root->sectorsize, tree_root->stripesize,
1453                      root, fs_info, key->objectid);
1454 
1455         ret = btrfs_find_root(tree_root, key, path,
1456                               &root->root_item, &root->root_key);
1457         if (ret) {
1458                 if (ret > 0)
1459                         ret = -ENOENT;
1460                 goto find_fail;
1461         }
1462 
1463         generation = btrfs_root_generation(&root->root_item);
1464         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1465         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1466                                      blocksize, generation);
1467         if (!root->node) {
1468                 ret = -ENOMEM;
1469                 goto find_fail;
1470         } else if (!btrfs_buffer_uptodate(root->node, generation, 0)) {
1471                 ret = -EIO;
1472                 goto read_fail;
1473         }
1474         root->commit_root = btrfs_root_node(root);
1475 out:
1476         btrfs_free_path(path);
1477         return root;
1478 
1479 read_fail:
1480         free_extent_buffer(root->node);
1481 find_fail:
1482         kfree(root);
1483 alloc_fail:
1484         root = ERR_PTR(ret);
1485         goto out;
1486 }
1487 
1488 struct btrfs_root *btrfs_read_fs_root(struct btrfs_root *tree_root,
1489                                       struct btrfs_key *location)
1490 {
1491         struct btrfs_root *root;
1492 
1493         root = btrfs_read_tree_root(tree_root, location);
1494         if (IS_ERR(root))
1495                 return root;
1496 
1497         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
1498                 root->ref_cows = 1;
1499                 btrfs_check_and_init_root_item(&root->root_item);
1500         }
1501 
1502         return root;
1503 }
1504 
1505 int btrfs_init_fs_root(struct btrfs_root *root)
1506 {
1507         int ret;
1508 
1509         root->free_ino_ctl = kzalloc(sizeof(*root->free_ino_ctl), GFP_NOFS);
1510         root->free_ino_pinned = kzalloc(sizeof(*root->free_ino_pinned),
1511                                         GFP_NOFS);
1512         if (!root->free_ino_pinned || !root->free_ino_ctl) {
1513                 ret = -ENOMEM;
1514                 goto fail;
1515         }
1516 
1517         btrfs_init_free_ino_ctl(root);
1518         mutex_init(&root->fs_commit_mutex);
1519         spin_lock_init(&root->cache_lock);
1520         init_waitqueue_head(&root->cache_wait);
1521 
1522         ret = get_anon_bdev(&root->anon_dev);
1523         if (ret)
1524                 goto fail;
1525         return 0;
1526 fail:
1527         kfree(root->free_ino_ctl);
1528         kfree(root->free_ino_pinned);
1529         return ret;
1530 }
1531 
1532 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
1533                                         u64 root_id)
1534 {
1535         struct btrfs_root *root;
1536 
1537         spin_lock(&fs_info->fs_roots_radix_lock);
1538         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1539                                  (unsigned long)root_id);
1540         spin_unlock(&fs_info->fs_roots_radix_lock);
1541         return root;
1542 }
1543 
1544 int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
1545                          struct btrfs_root *root)
1546 {
1547         int ret;
1548 
1549         ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
1550         if (ret)
1551                 return ret;
1552 
1553         spin_lock(&fs_info->fs_roots_radix_lock);
1554         ret = radix_tree_insert(&fs_info->fs_roots_radix,
1555                                 (unsigned long)root->root_key.objectid,
1556                                 root);
1557         if (ret == 0)
1558                 root->in_radix = 1;
1559         spin_unlock(&fs_info->fs_roots_radix_lock);
1560         radix_tree_preload_end();
1561 
1562         return ret;
1563 }
1564 
1565 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
1566                                               struct btrfs_key *location)
1567 {
1568         struct btrfs_root *root;
1569         int ret;
1570 
1571         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1572                 return fs_info->tree_root;
1573         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1574                 return fs_info->extent_root;
1575         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1576                 return fs_info->chunk_root;
1577         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1578                 return fs_info->dev_root;
1579         if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
1580                 return fs_info->csum_root;
1581         if (location->objectid == BTRFS_QUOTA_TREE_OBJECTID)
1582                 return fs_info->quota_root ? fs_info->quota_root :
1583                                              ERR_PTR(-ENOENT);
1584 again:
1585         root = btrfs_lookup_fs_root(fs_info, location->objectid);
1586         if (root)
1587                 return root;
1588 
1589         root = btrfs_read_fs_root(fs_info->tree_root, location);
1590         if (IS_ERR(root))
1591                 return root;
1592 
1593         if (btrfs_root_refs(&root->root_item) == 0) {
1594                 ret = -ENOENT;
1595                 goto fail;
1596         }
1597 
1598         ret = btrfs_init_fs_root(root);
1599         if (ret)
1600                 goto fail;
1601 
1602         ret = btrfs_find_orphan_item(fs_info->tree_root, location->objectid);
1603         if (ret < 0)
1604                 goto fail;
1605         if (ret == 0)
1606                 root->orphan_item_inserted = 1;
1607 
1608         ret = btrfs_insert_fs_root(fs_info, root);
1609         if (ret) {
1610                 if (ret == -EEXIST) {
1611                         free_fs_root(root);
1612                         goto again;
1613                 }
1614                 goto fail;
1615         }
1616         return root;
1617 fail:
1618         free_fs_root(root);
1619         return ERR_PTR(ret);
1620 }
1621 
1622 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1623 {
1624         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1625         int ret = 0;
1626         struct btrfs_device *device;
1627         struct backing_dev_info *bdi;
1628 
1629         rcu_read_lock();
1630         list_for_each_entry_rcu(device, &info->fs_devices->devices, dev_list) {
1631                 if (!device->bdev)
1632                         continue;
1633                 bdi = blk_get_backing_dev_info(device->bdev);
1634                 if (bdi && bdi_congested(bdi, bdi_bits)) {
1635                         ret = 1;
1636                         break;
1637                 }
1638         }
1639         rcu_read_unlock();
1640         return ret;
1641 }
1642 
1643 /*
1644  * If this fails, caller must call bdi_destroy() to get rid of the
1645  * bdi again.
1646  */
1647 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1648 {
1649         int err;
1650 
1651         bdi->capabilities = BDI_CAP_MAP_COPY;
1652         err = bdi_setup_and_register(bdi, "btrfs", BDI_CAP_MAP_COPY);
1653         if (err)
1654                 return err;
1655 
1656         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1657         bdi->congested_fn       = btrfs_congested_fn;
1658         bdi->congested_data     = info;
1659         return 0;
1660 }
1661 
1662 /*
1663  * called by the kthread helper functions to finally call the bio end_io
1664  * functions.  This is where read checksum verification actually happens
1665  */
1666 static void end_workqueue_fn(struct btrfs_work *work)
1667 {
1668         struct bio *bio;
1669         struct end_io_wq *end_io_wq;
1670         struct btrfs_fs_info *fs_info;
1671         int error;
1672 
1673         end_io_wq = container_of(work, struct end_io_wq, work);
1674         bio = end_io_wq->bio;
1675         fs_info = end_io_wq->info;
1676 
1677         error = end_io_wq->error;
1678         bio->bi_private = end_io_wq->private;
1679         bio->bi_end_io = end_io_wq->end_io;
1680         kfree(end_io_wq);
1681         bio_endio(bio, error);
1682 }
1683 
1684 static int cleaner_kthread(void *arg)
1685 {
1686         struct btrfs_root *root = arg;
1687         int again;
1688 
1689         do {
1690                 again = 0;
1691 
1692                 /* Make the cleaner go to sleep early. */
1693                 if (btrfs_need_cleaner_sleep(root))
1694                         goto sleep;
1695 
1696                 if (!mutex_trylock(&root->fs_info->cleaner_mutex))
1697                         goto sleep;
1698 
1699                 /*
1700                  * Avoid the problem that we change the status of the fs
1701                  * during the above check and trylock.
1702                  */
1703                 if (btrfs_need_cleaner_sleep(root)) {
1704                         mutex_unlock(&root->fs_info->cleaner_mutex);
1705                         goto sleep;
1706                 }
1707 
1708                 btrfs_run_delayed_iputs(root);
1709                 again = btrfs_clean_one_deleted_snapshot(root);
1710                 mutex_unlock(&root->fs_info->cleaner_mutex);
1711 
1712                 /*
1713                  * The defragger has dealt with the R/O remount and umount,
1714                  * needn't do anything special here.
1715                  */
1716                 btrfs_run_defrag_inodes(root->fs_info);
1717 sleep:
1718                 if (!try_to_freeze() && !again) {
1719                         set_current_state(TASK_INTERRUPTIBLE);
1720                         if (!kthread_should_stop())
1721                                 schedule();
1722                         __set_current_state(TASK_RUNNING);
1723                 }
1724         } while (!kthread_should_stop());
1725         return 0;
1726 }
1727 
1728 static int transaction_kthread(void *arg)
1729 {
1730         struct btrfs_root *root = arg;
1731         struct btrfs_trans_handle *trans;
1732         struct btrfs_transaction *cur;
1733         u64 transid;
1734         unsigned long now;
1735         unsigned long delay;
1736         bool cannot_commit;
1737 
1738         do {
1739                 cannot_commit = false;
1740                 delay = HZ * 30;
1741                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1742 
1743                 spin_lock(&root->fs_info->trans_lock);
1744                 cur = root->fs_info->running_transaction;
1745                 if (!cur) {
1746                         spin_unlock(&root->fs_info->trans_lock);
1747                         goto sleep;
1748                 }
1749 
1750                 now = get_seconds();
1751                 if (cur->state < TRANS_STATE_BLOCKED &&
1752                     (now < cur->start_time || now - cur->start_time < 30)) {
1753                         spin_unlock(&root->fs_info->trans_lock);
1754                         delay = HZ * 5;
1755                         goto sleep;
1756                 }
1757                 transid = cur->transid;
1758                 spin_unlock(&root->fs_info->trans_lock);
1759 
1760                 /* If the file system is aborted, this will always fail. */
1761                 trans = btrfs_attach_transaction(root);
1762                 if (IS_ERR(trans)) {
1763                         if (PTR_ERR(trans) != -ENOENT)
1764                                 cannot_commit = true;
1765                         goto sleep;
1766                 }
1767                 if (transid == trans->transid) {
1768                         btrfs_commit_transaction(trans, root);
1769                 } else {
1770                         btrfs_end_transaction(trans, root);
1771                 }
1772 sleep:
1773                 wake_up_process(root->fs_info->cleaner_kthread);
1774                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1775 
1776                 if (!try_to_freeze()) {
1777                         set_current_state(TASK_INTERRUPTIBLE);
1778                         if (!kthread_should_stop() &&
1779                             (!btrfs_transaction_blocked(root->fs_info) ||
1780                              cannot_commit))
1781                                 schedule_timeout(delay);
1782                         __set_current_state(TASK_RUNNING);
1783                 }
1784         } while (!kthread_should_stop());
1785         return 0;
1786 }
1787 
1788 /*
1789  * this will find the highest generation in the array of
1790  * root backups.  The index of the highest array is returned,
1791  * or -1 if we can't find anything.
1792  *
1793  * We check to make sure the array is valid by comparing the
1794  * generation of the latest  root in the array with the generation
1795  * in the super block.  If they don't match we pitch it.
1796  */
1797 static int find_newest_super_backup(struct btrfs_fs_info *info, u64 newest_gen)
1798 {
1799         u64 cur;
1800         int newest_index = -1;
1801         struct btrfs_root_backup *root_backup;
1802         int i;
1803 
1804         for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; i++) {
1805                 root_backup = info->super_copy->super_roots + i;
1806                 cur = btrfs_backup_tree_root_gen(root_backup);
1807                 if (cur == newest_gen)
1808                         newest_index = i;
1809         }
1810 
1811         /* check to see if we actually wrapped around */
1812         if (newest_index == BTRFS_NUM_BACKUP_ROOTS - 1) {
1813                 root_backup = info->super_copy->super_roots;
1814                 cur = btrfs_backup_tree_root_gen(root_backup);
1815                 if (cur == newest_gen)
1816                         newest_index = 0;
1817         }
1818         return newest_index;
1819 }
1820 
1821 
1822 /*
1823  * find the oldest backup so we know where to store new entries
1824  * in the backup array.  This will set the backup_root_index
1825  * field in the fs_info struct
1826  */
1827 static void find_oldest_super_backup(struct btrfs_fs_info *info,
1828                                      u64 newest_gen)
1829 {
1830         int newest_index = -1;
1831 
1832         newest_index = find_newest_super_backup(info, newest_gen);
1833         /* if there was garbage in there, just move along */
1834         if (newest_index == -1) {
1835                 info->backup_root_index = 0;
1836         } else {
1837                 info->backup_root_index = (newest_index + 1) % BTRFS_NUM_BACKUP_ROOTS;
1838         }
1839 }
1840 
1841 /*
1842  * copy all the root pointers into the super backup array.
1843  * this will bump the backup pointer by one when it is
1844  * done
1845  */
1846 static void backup_super_roots(struct btrfs_fs_info *info)
1847 {
1848         int next_backup;
1849         struct btrfs_root_backup *root_backup;
1850         int last_backup;
1851 
1852         next_backup = info->backup_root_index;
1853         last_backup = (next_backup + BTRFS_NUM_BACKUP_ROOTS - 1) %
1854                 BTRFS_NUM_BACKUP_ROOTS;
1855 
1856         /*
1857          * just overwrite the last backup if we're at the same generation
1858          * this happens only at umount
1859          */
1860         root_backup = info->super_for_commit->super_roots + last_backup;
1861         if (btrfs_backup_tree_root_gen(root_backup) ==
1862             btrfs_header_generation(info->tree_root->node))
1863                 next_backup = last_backup;
1864 
1865         root_backup = info->super_for_commit->super_roots + next_backup;
1866 
1867         /*
1868          * make sure all of our padding and empty slots get zero filled
1869          * regardless of which ones we use today
1870          */
1871         memset(root_backup, 0, sizeof(*root_backup));
1872 
1873         info->backup_root_index = (next_backup + 1) % BTRFS_NUM_BACKUP_ROOTS;
1874 
1875         btrfs_set_backup_tree_root(root_backup, info->tree_root->node->start);
1876         btrfs_set_backup_tree_root_gen(root_backup,
1877                                btrfs_header_generation(info->tree_root->node));
1878 
1879         btrfs_set_backup_tree_root_level(root_backup,
1880                                btrfs_header_level(info->tree_root->node));
1881 
1882         btrfs_set_backup_chunk_root(root_backup, info->chunk_root->node->start);
1883         btrfs_set_backup_chunk_root_gen(root_backup,
1884                                btrfs_header_generation(info->chunk_root->node));
1885         btrfs_set_backup_chunk_root_level(root_backup,
1886                                btrfs_header_level(info->chunk_root->node));
1887 
1888         btrfs_set_backup_extent_root(root_backup, info->extent_root->node->start);
1889         btrfs_set_backup_extent_root_gen(root_backup,
1890                                btrfs_header_generation(info->extent_root->node));
1891         btrfs_set_backup_extent_root_level(root_backup,
1892                                btrfs_header_level(info->extent_root->node));
1893 
1894         /*
1895          * we might commit during log recovery, which happens before we set
1896          * the fs_root.  Make sure it is valid before we fill it in.
1897          */
1898         if (info->fs_root && info->fs_root->node) {
1899                 btrfs_set_backup_fs_root(root_backup,
1900                                          info->fs_root->node->start);
1901                 btrfs_set_backup_fs_root_gen(root_backup,
1902                                btrfs_header_generation(info->fs_root->node));
1903                 btrfs_set_backup_fs_root_level(root_backup,
1904                                btrfs_header_level(info->fs_root->node));
1905         }
1906 
1907         btrfs_set_backup_dev_root(root_backup, info->dev_root->node->start);
1908         btrfs_set_backup_dev_root_gen(root_backup,
1909                                btrfs_header_generation(info->dev_root->node));
1910         btrfs_set_backup_dev_root_level(root_backup,
1911                                        btrfs_header_level(info->dev_root->node));
1912 
1913         btrfs_set_backup_csum_root(root_backup, info->csum_root->node->start);
1914         btrfs_set_backup_csum_root_gen(root_backup,
1915                                btrfs_header_generation(info->csum_root->node));
1916         btrfs_set_backup_csum_root_level(root_backup,
1917                                btrfs_header_level(info->csum_root->node));
1918 
1919         btrfs_set_backup_total_bytes(root_backup,
1920                              btrfs_super_total_bytes(info->super_copy));
1921         btrfs_set_backup_bytes_used(root_backup,
1922                              btrfs_super_bytes_used(info->super_copy));
1923         btrfs_set_backup_num_devices(root_backup,
1924                              btrfs_super_num_devices(info->super_copy));
1925 
1926         /*
1927          * if we don't copy this out to the super_copy, it won't get remembered
1928          * for the next commit
1929          */
1930         memcpy(&info->super_copy->super_roots,
1931                &info->super_for_commit->super_roots,
1932                sizeof(*root_backup) * BTRFS_NUM_BACKUP_ROOTS);
1933 }
1934 
1935 /*
1936  * this copies info out of the root backup array and back into
1937  * the in-memory super block.  It is meant to help iterate through
1938  * the array, so you send it the number of backups you've already
1939  * tried and the last backup index you used.
1940  *
1941  * this returns -1 when it has tried all the backups
1942  */
1943 static noinline int next_root_backup(struct btrfs_fs_info *info,
1944                                      struct btrfs_super_block *super,
1945                                      int *num_backups_tried, int *backup_index)
1946 {
1947         struct btrfs_root_backup *root_backup;
1948         int newest = *backup_index;
1949 
1950         if (*num_backups_tried == 0) {
1951                 u64 gen = btrfs_super_generation(super);
1952 
1953                 newest = find_newest_super_backup(info, gen);
1954                 if (newest == -1)
1955                         return -1;
1956 
1957                 *backup_index = newest;
1958                 *num_backups_tried = 1;
1959         } else if (*num_backups_tried == BTRFS_NUM_BACKUP_ROOTS) {
1960                 /* we've tried all the backups, all done */
1961                 return -1;
1962         } else {
1963                 /* jump to the next oldest backup */
1964                 newest = (*backup_index + BTRFS_NUM_BACKUP_ROOTS - 1) %
1965                         BTRFS_NUM_BACKUP_ROOTS;
1966                 *backup_index = newest;
1967                 *num_backups_tried += 1;
1968         }
1969         root_backup = super->super_roots + newest;
1970 
1971         btrfs_set_super_generation(super,
1972                                    btrfs_backup_tree_root_gen(root_backup));
1973         btrfs_set_super_root(super, btrfs_backup_tree_root(root_backup));
1974         btrfs_set_super_root_level(super,
1975                                    btrfs_backup_tree_root_level(root_backup));
1976         btrfs_set_super_bytes_used(super, btrfs_backup_bytes_used(root_backup));
1977 
1978         /*
1979          * fixme: the total bytes and num_devices need to match or we should
1980          * need a fsck
1981          */
1982         btrfs_set_super_total_bytes(super, btrfs_backup_total_bytes(root_backup));
1983         btrfs_set_super_num_devices(super, btrfs_backup_num_devices(root_backup));
1984         return 0;
1985 }
1986 
1987 /* helper to cleanup workers */
1988 static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
1989 {
1990         btrfs_stop_workers(&fs_info->generic_worker);
1991         btrfs_stop_workers(&fs_info->fixup_workers);
1992         btrfs_stop_workers(&fs_info->delalloc_workers);
1993         btrfs_stop_workers(&fs_info->workers);
1994         btrfs_stop_workers(&fs_info->endio_workers);
1995         btrfs_stop_workers(&fs_info->endio_meta_workers);
1996         btrfs_stop_workers(&fs_info->endio_raid56_workers);
1997         btrfs_stop_workers(&fs_info->rmw_workers);
1998         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
1999         btrfs_stop_workers(&fs_info->endio_write_workers);
2000         btrfs_stop_workers(&fs_info->endio_freespace_worker);
2001         btrfs_stop_workers(&fs_info->submit_workers);
2002         btrfs_stop_workers(&fs_info->delayed_workers);
2003         btrfs_stop_workers(&fs_info->caching_workers);
2004         btrfs_stop_workers(&fs_info->readahead_workers);
2005         btrfs_stop_workers(&fs_info->flush_workers);
2006         btrfs_stop_workers(&fs_info->qgroup_rescan_workers);
2007 }
2008 
2009 /* helper to cleanup tree roots */
2010 static void free_root_pointers(struct btrfs_fs_info *info, int chunk_root)
2011 {
2012         free_extent_buffer(info->tree_root->node);
2013         free_extent_buffer(info->tree_root->commit_root);
2014         info->tree_root->node = NULL;
2015         info->tree_root->commit_root = NULL;
2016 
2017         if (info->dev_root) {
2018                 free_extent_buffer(info->dev_root->node);
2019                 free_extent_buffer(info->dev_root->commit_root);
2020                 info->dev_root->node = NULL;
2021                 info->dev_root->commit_root = NULL;
2022         }
2023         if (info->extent_root) {
2024                 free_extent_buffer(info->extent_root->node);
2025                 free_extent_buffer(info->extent_root->commit_root);
2026                 info->extent_root->node = NULL;
2027                 info->extent_root->commit_root = NULL;
2028         }
2029         if (info->csum_root) {
2030                 free_extent_buffer(info->csum_root->node);
2031                 free_extent_buffer(info->csum_root->commit_root);
2032                 info->csum_root->node = NULL;
2033                 info->csum_root->commit_root = NULL;
2034         }
2035         if (info->quota_root) {
2036                 free_extent_buffer(info->quota_root->node);
2037                 free_extent_buffer(info->quota_root->commit_root);
2038                 info->quota_root->node = NULL;
2039                 info->quota_root->commit_root = NULL;
2040         }
2041         if (chunk_root) {
2042                 free_extent_buffer(info->chunk_root->node);
2043                 free_extent_buffer(info->chunk_root->commit_root);
2044                 info->chunk_root->node = NULL;
2045                 info->chunk_root->commit_root = NULL;
2046         }
2047 }
2048 
2049 static void del_fs_roots(struct btrfs_fs_info *fs_info)
2050 {
2051         int ret;
2052         struct btrfs_root *gang[8];
2053         int i;
2054 
2055         while (!list_empty(&fs_info->dead_roots)) {
2056                 gang[0] = list_entry(fs_info->dead_roots.next,
2057                                      struct btrfs_root, root_list);
2058                 list_del(&gang[0]->root_list);
2059 
2060                 if (gang[0]->in_radix) {
2061                         btrfs_drop_and_free_fs_root(fs_info, gang[0]);
2062                 } else {
2063                         free_extent_buffer(gang[0]->node);
2064                         free_extent_buffer(gang[0]->commit_root);
2065                         btrfs_put_fs_root(gang[0]);
2066                 }
2067         }
2068 
2069         while (1) {
2070                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2071                                              (void **)gang, 0,
2072                                              ARRAY_SIZE(gang));
2073                 if (!ret)
2074                         break;
2075                 for (i = 0; i < ret; i++)
2076                         btrfs_drop_and_free_fs_root(fs_info, gang[i]);
2077         }
2078 }
2079 
2080 int open_ctree(struct super_block *sb,
2081                struct btrfs_fs_devices *fs_devices,
2082                char *options)
2083 {
2084         u32 sectorsize;
2085         u32 nodesize;
2086         u32 leafsize;
2087         u32 blocksize;
2088         u32 stripesize;
2089         u64 generation;
2090         u64 features;
2091         struct btrfs_key location;
2092         struct buffer_head *bh;
2093         struct btrfs_super_block *disk_super;
2094         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2095         struct btrfs_root *tree_root;
2096         struct btrfs_root *extent_root;
2097         struct btrfs_root *csum_root;
2098         struct btrfs_root *chunk_root;
2099         struct btrfs_root *dev_root;
2100         struct btrfs_root *quota_root;
2101         struct btrfs_root *log_tree_root;
2102         int ret;
2103         int err = -EINVAL;
2104         int num_backups_tried = 0;
2105         int backup_index = 0;
2106 
2107         tree_root = fs_info->tree_root = btrfs_alloc_root(fs_info);
2108         chunk_root = fs_info->chunk_root = btrfs_alloc_root(fs_info);
2109         if (!tree_root || !chunk_root) {
2110                 err = -ENOMEM;
2111                 goto fail;
2112         }
2113 
2114         ret = init_srcu_struct(&fs_info->subvol_srcu);
2115         if (ret) {
2116                 err = ret;
2117                 goto fail;
2118         }
2119 
2120         ret = setup_bdi(fs_info, &fs_info->bdi);
2121         if (ret) {
2122                 err = ret;
2123                 goto fail_srcu;
2124         }
2125 
2126         ret = percpu_counter_init(&fs_info->dirty_metadata_bytes, 0);
2127         if (ret) {
2128                 err = ret;
2129                 goto fail_bdi;
2130         }
2131         fs_info->dirty_metadata_batch = PAGE_CACHE_SIZE *
2132                                         (1 + ilog2(nr_cpu_ids));
2133 
2134         ret = percpu_counter_init(&fs_info->delalloc_bytes, 0);
2135         if (ret) {
2136                 err = ret;
2137                 goto fail_dirty_metadata_bytes;
2138         }
2139 
2140         fs_info->btree_inode = new_inode(sb);
2141         if (!fs_info->btree_inode) {
2142                 err = -ENOMEM;
2143                 goto fail_delalloc_bytes;
2144         }
2145 
2146         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
2147 
2148         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
2149         INIT_LIST_HEAD(&fs_info->trans_list);
2150         INIT_LIST_HEAD(&fs_info->dead_roots);
2151         INIT_LIST_HEAD(&fs_info->delayed_iputs);
2152         INIT_LIST_HEAD(&fs_info->delalloc_roots);
2153         INIT_LIST_HEAD(&fs_info->caching_block_groups);
2154         spin_lock_init(&fs_info->delalloc_root_lock);
2155         spin_lock_init(&fs_info->trans_lock);
2156         spin_lock_init(&fs_info->fs_roots_radix_lock);
2157         spin_lock_init(&fs_info->delayed_iput_lock);
2158         spin_lock_init(&fs_info->defrag_inodes_lock);
2159         spin_lock_init(&fs_info->free_chunk_lock);
2160         spin_lock_init(&fs_info->tree_mod_seq_lock);
2161         spin_lock_init(&fs_info->super_lock);
2162         rwlock_init(&fs_info->tree_mod_log_lock);
2163         mutex_init(&fs_info->reloc_mutex);
2164         seqlock_init(&fs_info->profiles_lock);
2165 
2166         init_completion(&fs_info->kobj_unregister);
2167         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
2168         INIT_LIST_HEAD(&fs_info->space_info);
2169         INIT_LIST_HEAD(&fs_info->tree_mod_seq_list);
2170         btrfs_mapping_init(&fs_info->mapping_tree);
2171         btrfs_init_block_rsv(&fs_info->global_block_rsv,
2172                              BTRFS_BLOCK_RSV_GLOBAL);
2173         btrfs_init_block_rsv(&fs_info->delalloc_block_rsv,
2174                              BTRFS_BLOCK_RSV_DELALLOC);
2175         btrfs_init_block_rsv(&fs_info->trans_block_rsv, BTRFS_BLOCK_RSV_TRANS);
2176         btrfs_init_block_rsv(&fs_info->chunk_block_rsv, BTRFS_BLOCK_RSV_CHUNK);
2177         btrfs_init_block_rsv(&fs_info->empty_block_rsv, BTRFS_BLOCK_RSV_EMPTY);
2178         btrfs_init_block_rsv(&fs_info->delayed_block_rsv,
2179                              BTRFS_BLOCK_RSV_DELOPS);
2180         atomic_set(&fs_info->nr_async_submits, 0);
2181         atomic_set(&fs_info->async_delalloc_pages, 0);
2182         atomic_set(&fs_info->async_submit_draining, 0);
2183         atomic_set(&fs_info->nr_async_bios, 0);
2184         atomic_set(&fs_info->defrag_running, 0);
2185         atomic64_set(&fs_info->tree_mod_seq, 0);
2186         fs_info->sb = sb;
2187         fs_info->max_inline = 8192 * 1024;
2188         fs_info->metadata_ratio = 0;
2189         fs_info->defrag_inodes = RB_ROOT;
2190         fs_info->free_chunk_space = 0;
2191         fs_info->tree_mod_log = RB_ROOT;
2192 
2193         /* readahead state */
2194         INIT_RADIX_TREE(&fs_info->reada_tree, GFP_NOFS & ~__GFP_WAIT);
2195         spin_lock_init(&fs_info->reada_lock);
2196 
2197         fs_info->thread_pool_size = min_t(unsigned long,
2198                                           num_online_cpus() + 2, 8);
2199 
2200         INIT_LIST_HEAD(&fs_info->ordered_roots);
2201         spin_lock_init(&fs_info->ordered_root_lock);
2202         fs_info->delayed_root = kmalloc(sizeof(struct btrfs_delayed_root),
2203                                         GFP_NOFS);
2204         if (!fs_info->delayed_root) {
2205                 err = -ENOMEM;
2206                 goto fail_iput;
2207         }
2208         btrfs_init_delayed_root(fs_info->delayed_root);
2209 
2210         mutex_init(&fs_info->scrub_lock);
2211         atomic_set(&fs_info->scrubs_running, 0);
2212         atomic_set(&fs_info->scrub_pause_req, 0);
2213         atomic_set(&fs_info->scrubs_paused, 0);
2214         atomic_set(&fs_info->scrub_cancel_req, 0);
2215         init_waitqueue_head(&fs_info->scrub_pause_wait);
2216         init_rwsem(&fs_info->scrub_super_lock);
2217         fs_info->scrub_workers_refcnt = 0;
2218 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2219         fs_info->check_integrity_print_mask = 0;
2220 #endif
2221 
2222         spin_lock_init(&fs_info->balance_lock);
2223         mutex_init(&fs_info->balance_mutex);
2224         atomic_set(&fs_info->balance_running, 0);
2225         atomic_set(&fs_info->balance_pause_req, 0);
2226         atomic_set(&fs_info->balance_cancel_req, 0);
2227         fs_info->balance_ctl = NULL;
2228         init_waitqueue_head(&fs_info->balance_wait_q);
2229 
2230         sb->s_blocksize = 4096;
2231         sb->s_blocksize_bits = blksize_bits(4096);
2232         sb->s_bdi = &fs_info->bdi;
2233 
2234         fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
2235         set_nlink(fs_info->btree_inode, 1);
2236         /*
2237          * we set the i_size on the btree inode to the max possible int.
2238          * the real end of the address space is determined by all of
2239          * the devices in the system
2240          */
2241         fs_info->btree_inode->i_size = OFFSET_MAX;
2242         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
2243         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
2244 
2245         RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
2246         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
2247                              fs_info->btree_inode->i_mapping);
2248         BTRFS_I(fs_info->btree_inode)->io_tree.track_uptodate = 0;
2249         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree);
2250 
2251         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
2252 
2253         BTRFS_I(fs_info->btree_inode)->root = tree_root;
2254         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
2255                sizeof(struct btrfs_key));
2256         set_bit(BTRFS_INODE_DUMMY,
2257                 &BTRFS_I(fs_info->btree_inode)->runtime_flags);
2258         insert_inode_hash(fs_info->btree_inode);
2259 
2260         spin_lock_init(&fs_info->block_group_cache_lock);
2261         fs_info->block_group_cache_tree = RB_ROOT;
2262         fs_info->first_logical_byte = (u64)-1;
2263 
2264         extent_io_tree_init(&fs_info->freed_extents[0],
2265                              fs_info->btree_inode->i_mapping);
2266         extent_io_tree_init(&fs_info->freed_extents[1],
2267                              fs_info->btree_inode->i_mapping);
2268         fs_info->pinned_extents = &fs_info->freed_extents[0];
2269         fs_info->do_barriers = 1;
2270 
2271 
2272         mutex_init(&fs_info->ordered_operations_mutex);
2273         mutex_init(&fs_info->tree_log_mutex);
2274         mutex_init(&fs_info->chunk_mutex);
2275         mutex_init(&fs_info->transaction_kthread_mutex);
2276         mutex_init(&fs_info->cleaner_mutex);
2277         mutex_init(&fs_info->volume_mutex);
2278         init_rwsem(&fs_info->extent_commit_sem);
2279         init_rwsem(&fs_info->cleanup_work_sem);
2280         init_rwsem(&fs_info->subvol_sem);
2281         fs_info->dev_replace.lock_owner = 0;
2282         atomic_set(&fs_info->dev_replace.nesting_level, 0);
2283         mutex_init(&fs_info->dev_replace.lock_finishing_cancel_unmount);
2284         mutex_init(&fs_info->dev_replace.lock_management_lock);
2285         mutex_init(&fs_info->dev_replace.lock);
2286 
2287         spin_lock_init(&fs_info->qgroup_lock);
2288         mutex_init(&fs_info->qgroup_ioctl_lock);
2289         fs_info->qgroup_tree = RB_ROOT;
2290         INIT_LIST_HEAD(&fs_info->dirty_qgroups);
2291         fs_info->qgroup_seq = 1;
2292         fs_info->quota_enabled = 0;
2293         fs_info->pending_quota_state = 0;
2294         fs_info->qgroup_ulist = NULL;
2295         mutex_init(&fs_info->qgroup_rescan_lock);
2296 
2297         btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
2298         btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
2299 
2300         init_waitqueue_head(&fs_info->transaction_throttle);
2301         init_waitqueue_head(&fs_info->transaction_wait);
2302         init_waitqueue_head(&fs_info->transaction_blocked_wait);
2303         init_waitqueue_head(&fs_info->async_submit_wait);
2304 
2305         ret = btrfs_alloc_stripe_hash_table(fs_info);
2306         if (ret) {
2307                 err = ret;
2308                 goto fail_alloc;
2309         }
2310 
2311         __setup_root(4096, 4096, 4096, 4096, tree_root,
2312                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
2313 
2314         invalidate_bdev(fs_devices->latest_bdev);
2315 
2316         /*
2317          * Read super block and check the signature bytes only
2318          */
2319         bh = btrfs_read_dev_super(fs_devices->latest_bdev);
2320         if (!bh) {
2321                 err = -EINVAL;
2322                 goto fail_alloc;
2323         }
2324 
2325         /*
2326          * We want to check superblock checksum, the type is stored inside.
2327          * Pass the whole disk block of size BTRFS_SUPER_INFO_SIZE (4k).
2328          */
2329         if (btrfs_check_super_csum(bh->b_data)) {
2330                 printk(KERN_ERR "btrfs: superblock checksum mismatch\n");
2331                 err = -EINVAL;
2332                 goto fail_alloc;
2333         }
2334 
2335         /*
2336          * super_copy is zeroed at allocation time and we never touch the
2337          * following bytes up to INFO_SIZE, the checksum is calculated from
2338          * the whole block of INFO_SIZE
2339          */
2340         memcpy(fs_info->super_copy, bh->b_data, sizeof(*fs_info->super_copy));
2341         memcpy(fs_info->super_for_commit, fs_info->super_copy,
2342                sizeof(*fs_info->super_for_commit));
2343         brelse(bh);
2344 
2345         memcpy(fs_info->fsid, fs_info->super_copy->fsid, BTRFS_FSID_SIZE);
2346 
2347         ret = btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY);
2348         if (ret) {
2349                 printk(KERN_ERR "btrfs: superblock contains fatal errors\n");
2350                 err = -EINVAL;
2351                 goto fail_alloc;
2352         }
2353 
2354         disk_super = fs_info->super_copy;
2355         if (!btrfs_super_root(disk_super))
2356                 goto fail_alloc;
2357 
2358         /* check FS state, whether FS is broken. */
2359         if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_ERROR)
2360                 set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
2361 
2362         /*
2363          * run through our array of backup supers and setup
2364          * our ring pointer to the oldest one
2365          */
2366         generation = btrfs_super_generation(disk_super);
2367         find_oldest_super_backup(fs_info, generation);
2368 
2369         /*
2370          * In the long term, we'll store the compression type in the super
2371          * block, and it'll be used for per file compression control.
2372          */
2373         fs_info->compress_type = BTRFS_COMPRESS_ZLIB;
2374 
2375         ret = btrfs_parse_options(tree_root, options);
2376         if (ret) {
2377                 err = ret;
2378                 goto fail_alloc;
2379         }
2380 
2381         features = btrfs_super_incompat_flags(disk_super) &
2382                 ~BTRFS_FEATURE_INCOMPAT_SUPP;
2383         if (features) {
2384                 printk(KERN_ERR "BTRFS: couldn't mount because of "
2385                        "unsupported optional features (%Lx).\n",
2386                        (unsigned long long)features);
2387                 err = -EINVAL;
2388                 goto fail_alloc;
2389         }
2390 
2391         if (btrfs_super_leafsize(disk_super) !=
2392             btrfs_super_nodesize(disk_super)) {
2393                 printk(KERN_ERR "BTRFS: couldn't mount because metadata "
2394                        "blocksizes don't match.  node %d leaf %d\n",
2395                        btrfs_super_nodesize(disk_super),
2396                        btrfs_super_leafsize(disk_super));
2397                 err = -EINVAL;
2398                 goto fail_alloc;
2399         }
2400         if (btrfs_super_leafsize(disk_super) > BTRFS_MAX_METADATA_BLOCKSIZE) {
2401                 printk(KERN_ERR "BTRFS: couldn't mount because metadata "
2402                        "blocksize (%d) was too large\n",
2403                        btrfs_super_leafsize(disk_super));
2404                 err = -EINVAL;
2405                 goto fail_alloc;
2406         }
2407 
2408         features = btrfs_super_incompat_flags(disk_super);
2409         features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
2410         if (tree_root->fs_info->compress_type == BTRFS_COMPRESS_LZO)
2411                 features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
2412 
2413         if (features & BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA)
2414                 printk(KERN_ERR "btrfs: has skinny extents\n");
2415 
2416         /*
2417          * flag our filesystem as having big metadata blocks if
2418          * they are bigger than the page size
2419          */
2420         if (btrfs_super_leafsize(disk_super) > PAGE_CACHE_SIZE) {
2421                 if (!(features & BTRFS_FEATURE_INCOMPAT_BIG_METADATA))
2422                         printk(KERN_INFO "btrfs flagging fs with big metadata feature\n");
2423                 features |= BTRFS_FEATURE_INCOMPAT_BIG_METADATA;
2424         }
2425 
2426         nodesize = btrfs_super_nodesize(disk_super);
2427         leafsize = btrfs_super_leafsize(disk_super);
2428         sectorsize = btrfs_super_sectorsize(disk_super);
2429         stripesize = btrfs_super_stripesize(disk_super);
2430         fs_info->dirty_metadata_batch = leafsize * (1 + ilog2(nr_cpu_ids));
2431         fs_info->delalloc_batch = sectorsize * 512 * (1 + ilog2(nr_cpu_ids));
2432 
2433         /*
2434          * mixed block groups end up with duplicate but slightly offset
2435          * extent buffers for the same range.  It leads to corruptions
2436          */
2437         if ((features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS) &&
2438             (sectorsize != leafsize)) {
2439                 printk(KERN_WARNING "btrfs: unequal leaf/node/sector sizes "
2440                                 "are not allowed for mixed block groups on %s\n",
2441                                 sb->s_id);
2442                 goto fail_alloc;
2443         }
2444 
2445         /*
2446          * Needn't use the lock because there is no other task which will
2447          * update the flag.
2448          */
2449         btrfs_set_super_incompat_flags(disk_super, features);
2450 
2451         features = btrfs_super_compat_ro_flags(disk_super) &
2452                 ~BTRFS_FEATURE_COMPAT_RO_SUPP;
2453         if (!(sb->s_flags & MS_RDONLY) && features) {
2454                 printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
2455                        "unsupported option features (%Lx).\n",
2456                        (unsigned long long)features);
2457                 err = -EINVAL;
2458                 goto fail_alloc;
2459         }
2460 
2461         btrfs_init_workers(&fs_info->generic_worker,
2462                            "genwork", 1, NULL);
2463 
2464         btrfs_init_workers(&fs_info->workers, "worker",
2465                            fs_info->thread_pool_size,
2466                            &fs_info->generic_worker);
2467 
2468         btrfs_init_workers(&fs_info->delalloc_workers, "delalloc",
2469                            fs_info->thread_pool_size,
2470                            &fs_info->generic_worker);
2471 
2472         btrfs_init_workers(&fs_info->flush_workers, "flush_delalloc",
2473                            fs_info->thread_pool_size,
2474                            &fs_info->generic_worker);
2475 
2476         btrfs_init_workers(&fs_info->submit_workers, "submit",
2477                            min_t(u64, fs_devices->num_devices,
2478                            fs_info->thread_pool_size),
2479                            &fs_info->generic_worker);
2480 
2481         btrfs_init_workers(&fs_info->caching_workers, "cache",
2482                            2, &fs_info->generic_worker);
2483 
2484         /* a higher idle thresh on the submit workers makes it much more
2485          * likely that bios will be send down in a sane order to the
2486          * devices
2487          */
2488         fs_info->submit_workers.idle_thresh = 64;
2489 
2490         fs_info->workers.idle_thresh = 16;
2491         fs_info->workers.ordered = 1;
2492 
2493         fs_info->delalloc_workers.idle_thresh = 2;
2494         fs_info->delalloc_workers.ordered = 1;
2495 
2496         btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1,
2497                            &fs_info->generic_worker);
2498         btrfs_init_workers(&fs_info->endio_workers, "endio",
2499                            fs_info->thread_pool_size,
2500                            &fs_info->generic_worker);
2501         btrfs_init_workers(&fs_info->endio_meta_workers, "endio-meta",
2502                            fs_info->thread_pool_size,
2503                            &fs_info->generic_worker);
2504         btrfs_init_workers(&fs_info->endio_meta_write_workers,
2505                            "endio-meta-write", fs_info->thread_pool_size,
2506                            &fs_info->generic_worker);
2507         btrfs_init_workers(&fs_info->endio_raid56_workers,
2508                            "endio-raid56", fs_info->thread_pool_size,
2509                            &fs_info->generic_worker);
2510         btrfs_init_workers(&fs_info->rmw_workers,
2511                            "rmw", fs_info->thread_pool_size,
2512                            &fs_info->generic_worker);
2513         btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
2514                            fs_info->thread_pool_size,
2515                            &fs_info->generic_worker);
2516         btrfs_init_workers(&fs_info->endio_freespace_worker, "freespace-write",
2517                            1, &fs_info->generic_worker);
2518         btrfs_init_workers(&fs_info->delayed_workers, "delayed-meta",
2519                            fs_info->thread_pool_size,
2520                            &fs_info->generic_worker);
2521         btrfs_init_workers(&fs_info->readahead_workers, "readahead",
2522                            fs_info->thread_pool_size,
2523                            &fs_info->generic_worker);
2524         btrfs_init_workers(&fs_info->qgroup_rescan_workers, "qgroup-rescan", 1,
2525                            &fs_info->generic_worker);
2526 
2527         /*
2528          * endios are largely parallel and should have a very
2529          * low idle thresh
2530          */
2531         fs_info->endio_workers.idle_thresh = 4;
2532         fs_info->endio_meta_workers.idle_thresh = 4;
2533         fs_info->endio_raid56_workers.idle_thresh = 4;
2534         fs_info->rmw_workers.idle_thresh = 2;
2535 
2536         fs_info->endio_write_workers.idle_thresh = 2;
2537         fs_info->endio_meta_write_workers.idle_thresh = 2;
2538         fs_info->readahead_workers.idle_thresh = 2;
2539 
2540         /*
2541          * btrfs_start_workers can really only fail because of ENOMEM so just
2542          * return -ENOMEM if any of these fail.
2543          */
2544         ret = btrfs_start_workers(&fs_info->workers);
2545         ret |= btrfs_start_workers(&fs_info->generic_worker);
2546         ret |= btrfs_start_workers(&fs_info->submit_workers);
2547         ret |= btrfs_start_workers(&fs_info->delalloc_workers);
2548         ret |= btrfs_start_workers(&fs_info->fixup_workers);
2549         ret |= btrfs_start_workers(&fs_info->endio_workers);
2550         ret |= btrfs_start_workers(&fs_info->endio_meta_workers);
2551         ret |= btrfs_start_workers(&fs_info->rmw_workers);
2552         ret |= btrfs_start_workers(&fs_info->endio_raid56_workers);
2553         ret |= btrfs_start_workers(&fs_info->endio_meta_write_workers);
2554         ret |= btrfs_start_workers(&fs_info->endio_write_workers);
2555         ret |= btrfs_start_workers(&fs_info->endio_freespace_worker);
2556         ret |= btrfs_start_workers(&fs_info->delayed_workers);
2557         ret |= btrfs_start_workers(&fs_info->caching_workers);
2558         ret |= btrfs_start_workers(&fs_info->readahead_workers);
2559         ret |= btrfs_start_workers(&fs_info->flush_workers);
2560         ret |= btrfs_start_workers(&fs_info->qgroup_rescan_workers);
2561         if (ret) {
2562                 err = -ENOMEM;
2563                 goto fail_sb_buffer;
2564         }
2565 
2566         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
2567         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
2568                                     4 * 1024 * 1024 / PAGE_CACHE_SIZE);
2569 
2570         tree_root->nodesize = nodesize;
2571         tree_root->leafsize = leafsize;
2572         tree_root->sectorsize = sectorsize;
2573         tree_root->stripesize = stripesize;
2574 
2575         sb->s_blocksize = sectorsize;
2576         sb->s_blocksize_bits = blksize_bits(sectorsize);
2577 
2578         if (disk_super->magic != cpu_to_le64(BTRFS_MAGIC)) {
2579                 printk(KERN_INFO "btrfs: valid FS not found on %s\n", sb->s_id);
2580                 goto fail_sb_buffer;
2581         }
2582 
2583         if (sectorsize != PAGE_SIZE) {
2584                 printk(KERN_WARNING "btrfs: Incompatible sector size(%lu) "
2585                        "found on %s\n", (unsigned long)sectorsize, sb->s_id);
2586                 goto fail_sb_buffer;
2587         }
2588 
2589         mutex_lock(&fs_info->chunk_mutex);
2590         ret = btrfs_read_sys_array(tree_root);
2591         mutex_unlock(&fs_info->chunk_mutex);
2592         if (ret) {
2593                 printk(KERN_WARNING "btrfs: failed to read the system "
2594                        "array on %s\n", sb->s_id);
2595                 goto fail_sb_buffer;
2596         }
2597 
2598         blocksize = btrfs_level_size(tree_root,
2599                                      btrfs_super_chunk_root_level(disk_super));
2600         generation = btrfs_super_chunk_root_generation(disk_super);
2601 
2602         __setup_root(nodesize, leafsize, sectorsize, stripesize,
2603                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
2604 
2605         chunk_root->node = read_tree_block(chunk_root,
2606                                            btrfs_super_chunk_root(disk_super),
2607                                            blocksize, generation);
2608         if (!chunk_root->node ||
2609             !test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
2610                 printk(KERN_WARNING "btrfs: failed to read chunk root on %s\n",
2611                        sb->s_id);
2612                 goto fail_tree_roots;
2613         }
2614         btrfs_set_root_node(&chunk_root->root_item, chunk_root->node);
2615         chunk_root->commit_root = btrfs_root_node(chunk_root);
2616 
2617         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
2618            (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
2619            BTRFS_UUID_SIZE);
2620 
2621         ret = btrfs_read_chunk_tree(chunk_root);
2622         if (ret) {
2623                 printk(KERN_WARNING "btrfs: failed to read chunk tree on %s\n",
2624                        sb->s_id);
2625                 goto fail_tree_roots;
2626         }
2627 
2628         /*
2629          * keep the device that is marked to be the target device for the
2630          * dev_replace procedure
2631          */
2632         btrfs_close_extra_devices(fs_info, fs_devices, 0);
2633 
2634         if (!fs_devices->latest_bdev) {
2635                 printk(KERN_CRIT "btrfs: failed to read devices on %s\n",
2636                        sb->s_id);
2637                 goto fail_tree_roots;
2638         }
2639 
2640 retry_root_backup:
2641         blocksize = btrfs_level_size(tree_root,
2642                                      btrfs_super_root_level(disk_super));
2643         generation = btrfs_super_generation(disk_super);
2644 
2645         tree_root->node = read_tree_block(tree_root,
2646                                           btrfs_super_root(disk_super),
2647                                           blocksize, generation);
2648         if (!tree_root->node ||
2649             !test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) {
2650                 printk(KERN_WARNING "btrfs: failed to read tree root on %s\n",
2651                        sb->s_id);
2652 
2653                 goto recovery_tree_root;
2654         }
2655 
2656         btrfs_set_root_node(&tree_root->root_item, tree_root->node);
2657         tree_root->commit_root = btrfs_root_node(tree_root);
2658 
2659         location.objectid = BTRFS_EXTENT_TREE_OBJECTID;
2660         location.type = BTRFS_ROOT_ITEM_KEY;
2661         location.offset = 0;
2662 
2663         extent_root = btrfs_read_tree_root(tree_root, &location);
2664         if (IS_ERR(extent_root)) {
2665                 ret = PTR_ERR(extent_root);
2666                 goto recovery_tree_root;
2667         }
2668         extent_root->track_dirty = 1;
2669         fs_info->extent_root = extent_root;
2670 
2671         location.objectid = BTRFS_DEV_TREE_OBJECTID;
2672         dev_root = btrfs_read_tree_root(tree_root, &location);
2673         if (IS_ERR(dev_root)) {
2674                 ret = PTR_ERR(dev_root);
2675                 goto recovery_tree_root;
2676         }
2677         dev_root->track_dirty = 1;
2678         fs_info->dev_root = dev_root;
2679         btrfs_init_devices_late(fs_info);
2680 
2681         location.objectid = BTRFS_CSUM_TREE_OBJECTID;
2682         csum_root = btrfs_read_tree_root(tree_root, &location);
2683         if (IS_ERR(csum_root)) {
2684                 ret = PTR_ERR(csum_root);
2685                 goto recovery_tree_root;
2686         }
2687         csum_root->track_dirty = 1;
2688         fs_info->csum_root = csum_root;
2689 
2690         location.objectid = BTRFS_QUOTA_TREE_OBJECTID;
2691         quota_root = btrfs_read_tree_root(tree_root, &location);
2692         if (!IS_ERR(quota_root)) {
2693                 quota_root->track_dirty = 1;
2694                 fs_info->quota_enabled = 1;
2695                 fs_info->pending_quota_state = 1;
2696                 fs_info->quota_root = quota_root;
2697         }
2698 
2699         fs_info->generation = generation;
2700         fs_info->last_trans_committed = generation;
2701 
2702         ret = btrfs_recover_balance(fs_info);
2703         if (ret) {
2704                 printk(KERN_WARNING "btrfs: failed to recover balance\n");
2705                 goto fail_block_groups;
2706         }
2707 
2708         ret = btrfs_init_dev_stats(fs_info);
2709         if (ret) {
2710                 printk(KERN_ERR "btrfs: failed to init dev_stats: %d\n",
2711                        ret);
2712                 goto fail_block_groups;
2713         }
2714 
2715         ret = btrfs_init_dev_replace(fs_info);
2716         if (ret) {
2717                 pr_err("btrfs: failed to init dev_replace: %d\n", ret);
2718                 goto fail_block_groups;
2719         }
2720 
2721         btrfs_close_extra_devices(fs_info, fs_devices, 1);
2722 
2723         ret = btrfs_init_space_info(fs_info);
2724         if (ret) {
2725                 printk(KERN_ERR "Failed to initial space info: %d\n", ret);
2726                 goto fail_block_groups;
2727         }
2728 
2729         ret = btrfs_read_block_groups(extent_root);
2730         if (ret) {
2731                 printk(KERN_ERR "Failed to read block groups: %d\n", ret);
2732                 goto fail_block_groups;
2733         }
2734         fs_info->num_tolerated_disk_barrier_failures =
2735                 btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
2736         if (fs_info->fs_devices->missing_devices >
2737              fs_info->num_tolerated_disk_barrier_failures &&
2738             !(sb->s_flags & MS_RDONLY)) {
2739                 printk(KERN_WARNING
2740                        "Btrfs: too many missing devices, writeable mount is not allowed\n");
2741                 goto fail_block_groups;
2742         }
2743 
2744         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
2745                                                "btrfs-cleaner");
2746         if (IS_ERR(fs_info->cleaner_kthread))
2747                 goto fail_block_groups;
2748 
2749         fs_info->transaction_kthread = kthread_run(transaction_kthread,
2750                                                    tree_root,
2751                                                    "btrfs-transaction");
2752         if (IS_ERR(fs_info->transaction_kthread))
2753                 goto fail_cleaner;
2754 
2755         if (!btrfs_test_opt(tree_root, SSD) &&
2756             !btrfs_test_opt(tree_root, NOSSD) &&
2757             !fs_info->fs_devices->rotating) {
2758                 printk(KERN_INFO "Btrfs detected SSD devices, enabling SSD "
2759                        "mode\n");
2760                 btrfs_set_opt(fs_info->mount_opt, SSD);
2761         }
2762 
2763 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2764         if (btrfs_test_opt(tree_root, CHECK_INTEGRITY)) {
2765                 ret = btrfsic_mount(tree_root, fs_devices,
2766                                     btrfs_test_opt(tree_root,
2767                                         CHECK_INTEGRITY_INCLUDING_EXTENT_DATA) ?
2768                                     1 : 0,
2769                                     fs_info->check_integrity_print_mask);
2770                 if (ret)
2771                         printk(KERN_WARNING "btrfs: failed to initialize"
2772                                " integrity check module %s\n", sb->s_id);
2773         }
2774 #endif
2775         ret = btrfs_read_qgroup_config(fs_info);
2776         if (ret)
2777                 goto fail_trans_kthread;
2778 
2779         /* do not make disk changes in broken FS */
2780         if (btrfs_super_log_root(disk_super) != 0) {
2781                 u64 bytenr = btrfs_super_log_root(disk_super);
2782 
2783                 if (fs_devices->rw_devices == 0) {
2784                         printk(KERN_WARNING "Btrfs log replay required "
2785                                "on RO media\n");
2786                         err = -EIO;
2787                         goto fail_qgroup;
2788                 }
2789                 blocksize =
2790                      btrfs_level_size(tree_root,
2791                                       btrfs_super_log_root_level(disk_super));
2792 
2793                 log_tree_root = btrfs_alloc_root(fs_info);
2794                 if (!log_tree_root) {
2795                         err = -ENOMEM;
2796                         goto fail_qgroup;
2797                 }
2798 
2799                 __setup_root(nodesize, leafsize, sectorsize, stripesize,
2800                              log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
2801 
2802                 log_tree_root->node = read_tree_block(tree_root, bytenr,
2803                                                       blocksize,
2804                                                       generation + 1);
2805                 if (!log_tree_root->node ||
2806                     !extent_buffer_uptodate(log_tree_root->node)) {
2807                         printk(KERN_ERR "btrfs: failed to read log tree\n");
2808                         free_extent_buffer(log_tree_root->node);
2809                         kfree(log_tree_root);
2810                         goto fail_trans_kthread;
2811                 }
2812                 /* returns with log_tree_root freed on success */
2813                 ret = btrfs_recover_log_trees(log_tree_root);
2814                 if (ret) {
2815                         btrfs_error(tree_root->fs_info, ret,
2816                                     "Failed to recover log tree");
2817                         free_extent_buffer(log_tree_root->node);
2818                         kfree(log_tree_root);
2819                         goto fail_trans_kthread;
2820                 }
2821 
2822                 if (sb->s_flags & MS_RDONLY) {
2823                         ret = btrfs_commit_super(tree_root);
2824                         if (ret)
2825                                 goto fail_trans_kthread;
2826                 }
2827         }
2828 
2829         ret = btrfs_find_orphan_roots(tree_root);
2830         if (ret)
2831                 goto fail_trans_kthread;
2832 
2833         if (!(sb->s_flags & MS_RDONLY)) {
2834                 ret = btrfs_cleanup_fs_roots(fs_info);
2835                 if (ret)
2836                         goto fail_trans_kthread;
2837 
2838                 ret = btrfs_recover_relocation(tree_root);
2839                 if (ret < 0) {
2840                         printk(KERN_WARNING
2841                                "btrfs: failed to recover relocation\n");
2842                         err = -EINVAL;
2843                         goto fail_qgroup;
2844                 }
2845         }
2846 
2847         location.objectid = BTRFS_FS_TREE_OBJECTID;
2848         location.type = BTRFS_ROOT_ITEM_KEY;
2849         location.offset = 0;
2850 
2851         fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
2852         if (IS_ERR(fs_info->fs_root)) {
2853                 err = PTR_ERR(fs_info->fs_root);
2854                 goto fail_qgroup;
2855         }
2856 
2857         if (sb->s_flags & MS_RDONLY)
2858                 return 0;
2859 
2860         down_read(&fs_info->cleanup_work_sem);
2861         if ((ret = btrfs_orphan_cleanup(fs_info->fs_root)) ||
2862             (ret = btrfs_orphan_cleanup(fs_info->tree_root))) {
2863                 up_read(&fs_info->cleanup_work_sem);
2864                 close_ctree(tree_root);
2865                 return ret;
2866         }
2867         up_read(&fs_info->cleanup_work_sem);
2868 
2869         ret = btrfs_resume_balance_async(fs_info);
2870         if (ret) {
2871                 printk(KERN_WARNING "btrfs: failed to resume balance\n");
2872                 close_ctree(tree_root);
2873                 return ret;
2874         }
2875 
2876         ret = btrfs_resume_dev_replace_async(fs_info);
2877         if (ret) {
2878                 pr_warn("btrfs: failed to resume dev_replace\n");
2879                 close_ctree(tree_root);
2880                 return ret;
2881         }
2882 
2883         btrfs_qgroup_rescan_resume(fs_info);
2884 
2885         return 0;
2886 
2887 fail_qgroup:
2888         btrfs_free_qgroup_config(fs_info);
2889 fail_trans_kthread:
2890         kthread_stop(fs_info->transaction_kthread);
2891         btrfs_cleanup_transaction(fs_info->tree_root);
2892         del_fs_roots(fs_info);
2893 fail_cleaner:
2894         kthread_stop(fs_info->cleaner_kthread);
2895 
2896         /*
2897          * make sure we're done with the btree inode before we stop our
2898          * kthreads
2899          */
2900         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
2901 
2902 fail_block_groups:
2903         btrfs_put_block_group_cache(fs_info);
2904         btrfs_free_block_groups(fs_info);
2905 
2906 fail_tree_roots:
2907         free_root_pointers(fs_info, 1);
2908         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2909 
2910 fail_sb_buffer:
2911         btrfs_stop_all_workers(fs_info);
2912 fail_alloc:
2913 fail_iput:
2914         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2915 
2916         iput(fs_info->btree_inode);
2917 fail_delalloc_bytes:
2918         percpu_counter_destroy(&fs_info->delalloc_bytes);
2919 fail_dirty_metadata_bytes:
2920         percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
2921 fail_bdi:
2922         bdi_destroy(&fs_info->bdi);
2923 fail_srcu:
2924         cleanup_srcu_struct(&fs_info->subvol_srcu);
2925 fail:
2926         btrfs_free_stripe_hash_table(fs_info);
2927         btrfs_close_devices(fs_info->fs_devices);
2928         return err;
2929 
2930 recovery_tree_root:
2931         if (!btrfs_test_opt(tree_root, RECOVERY))
2932                 goto fail_tree_roots;
2933 
2934         free_root_pointers(fs_info, 0);
2935 
2936         /* don't use the log in recovery mode, it won't be valid */
2937         btrfs_set_super_log_root(disk_super, 0);
2938 
2939         /* we can't trust the free space cache either */
2940         btrfs_set_opt(fs_info->mount_opt, CLEAR_CACHE);
2941 
2942         ret = next_root_backup(fs_info, fs_info->super_copy,
2943                                &num_backups_tried, &backup_index);
2944         if (ret == -1)
2945                 goto fail_block_groups;
2946         goto retry_root_backup;
2947 }
2948 
2949 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
2950 {
2951         if (uptodate) {
2952                 set_buffer_uptodate(bh);
2953         } else {
2954                 struct btrfs_device *device = (struct btrfs_device *)
2955                         bh->b_private;
2956 
2957                 printk_ratelimited_in_rcu(KERN_WARNING "lost page write due to "
2958                                           "I/O error on %s\n",
2959                                           rcu_str_deref(device->name));
2960                 /* note, we dont' set_buffer_write_io_error because we have
2961                  * our own ways of dealing with the IO errors
2962                  */
2963                 clear_buffer_uptodate(bh);
2964                 btrfs_dev_stat_inc_and_print(device, BTRFS_DEV_STAT_WRITE_ERRS);
2965         }
2966         unlock_buffer(bh);
2967         put_bh(bh);
2968 }
2969 
2970 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
2971 {
2972         struct buffer_head *bh;
2973         struct buffer_head *latest = NULL;
2974         struct btrfs_super_block *super;
2975         int i;
2976         u64 transid = 0;
2977         u64 bytenr;
2978 
2979         /* we would like to check all the supers, but that would make
2980          * a btrfs mount succeed after a mkfs from a different FS.
2981          * So, we need to add a special mount option to scan for
2982          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
2983          */
2984         for (i = 0; i < 1; i++) {
2985                 bytenr = btrfs_sb_offset(i);
2986                 if (bytenr + 4096 >= i_size_read(bdev->bd_inode))
2987                         break;
2988                 bh = __bread(bdev, bytenr / 4096, 4096);
2989                 if (!bh)
2990                         continue;
2991 
2992                 super = (struct btrfs_super_block *)bh->b_data;
2993                 if (btrfs_super_bytenr(super) != bytenr ||
2994                     super->magic != cpu_to_le64(BTRFS_MAGIC)) {
2995                         brelse(bh);
2996                         continue;
2997                 }
2998 
2999                 if (!latest || btrfs_super_generation(super) > transid) {
3000                         brelse(latest);
3001                         latest = bh;
3002                         transid = btrfs_super_generation(super);
3003                 } else {
3004                         brelse(bh);
3005                 }
3006         }
3007         return latest;
3008 }
3009 
3010 /*
3011  * this should be called twice, once with wait == 0 and
3012  * once with wait == 1.  When wait == 0 is done, all the buffer heads
3013  * we write are pinned.
3014  *
3015  * They are released when wait == 1 is done.
3016  * max_mirrors must be the same for both runs, and it indicates how
3017  * many supers on this one device should be written.
3018  *
3019  * max_mirrors == 0 means to write them all.
3020  */
3021 static int write_dev_supers(struct btrfs_device *device,
3022                             struct btrfs_super_block *sb,
3023                             int do_barriers, int wait, int max_mirrors)
3024 {
3025         struct buffer_head *bh;
3026         int i;
3027         int ret;
3028         int errors = 0;
3029         u32 crc;
3030         u64 bytenr;
3031 
3032         if (max_mirrors == 0)
3033                 max_mirrors = BTRFS_SUPER_MIRROR_MAX;
3034 
3035         for (i = 0; i < max_mirrors; i++) {
3036                 bytenr = btrfs_sb_offset(i);
3037                 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
3038                         break;
3039 
3040                 if (wait) {
3041                         bh = __find_get_block(device->bdev, bytenr / 4096,
3042                                               BTRFS_SUPER_INFO_SIZE);
3043                         if (!bh) {
3044                                 errors++;
3045                                 continue;
3046                         }
3047                         wait_on_buffer(bh);
3048                         if (!buffer_uptodate(bh))
3049                                 errors++;
3050 
3051                         /* drop our reference */
3052                         brelse(bh);
3053 
3054                         /* drop the reference from the wait == 0 run */
3055                         brelse(bh);
3056                         continue;
3057                 } else {
3058                         btrfs_set_super_bytenr(sb, bytenr);
3059 
3060                         crc = ~(u32)0;
3061                         crc = btrfs_csum_data((char *)sb +
3062                                               BTRFS_CSUM_SIZE, crc,
3063                                               BTRFS_SUPER_INFO_SIZE -
3064                                               BTRFS_CSUM_SIZE);
3065                         btrfs_csum_final(crc, sb->csum);
3066 
3067                         /*
3068                          * one reference for us, and we leave it for the
3069                          * caller
3070                          */
3071                         bh = __getblk(device->bdev, bytenr / 4096,
3072                                       BTRFS_SUPER_INFO_SIZE);
3073                         if (!bh) {
3074                                 printk(KERN_ERR "btrfs: couldn't get super "
3075                                        "buffer head for bytenr %Lu\n", bytenr);
3076                                 errors++;
3077                                 continue;
3078                         }
3079 
3080                         memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
3081 
3082                         /* one reference for submit_bh */
3083                         get_bh(bh);
3084 
3085                         set_buffer_uptodate(bh);
3086                         lock_buffer(bh);
3087                         bh->b_end_io = btrfs_end_buffer_write_sync;
3088                         bh->b_private = device;
3089                 }
3090 
3091                 /*
3092                  * we fua the first super.  The others we allow
3093                  * to go down lazy.
3094                  */
3095                 ret = btrfsic_submit_bh(WRITE_FUA, bh);
3096                 if (ret)
3097                         errors++;
3098         }
3099         return errors < i ? 0 : -1;
3100 }
3101 
3102 /*
3103  * endio for the write_dev_flush, this will wake anyone waiting
3104  * for the barrier when it is done
3105  */
3106 static void btrfs_end_empty_barrier(struct bio *bio, int err)
3107 {
3108         if (err) {
3109                 if (err == -EOPNOTSUPP)
3110                         set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
3111                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
3112         }
3113         if (bio->bi_private)
3114                 complete(bio->bi_private);
3115         bio_put(bio);
3116 }
3117 
3118 /*
3119  * trigger flushes for one the devices.  If you pass wait == 0, the flushes are
3120  * sent down.  With wait == 1, it waits for the previous flush.
3121  *
3122  * any device where the flush fails with eopnotsupp are flagged as not-barrier
3123  * capable
3124  */
3125 static int write_dev_flush(struct btrfs_device *device, int wait)
3126 {
3127         struct bio *bio;
3128         int ret = 0;
3129 
3130         if (device->nobarriers)
3131                 return 0;
3132 
3133         if (wait) {
3134                 bio = device->flush_bio;
3135                 if (!bio)
3136                         return 0;
3137 
3138                 wait_for_completion(&device->flush_wait);
3139 
3140                 if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
3141                         printk_in_rcu("btrfs: disabling barriers on dev %s\n",
3142                                       rcu_str_deref(device->name));
3143                         device->nobarriers = 1;
3144                 } else if (!bio_flagged(bio, BIO_UPTODATE)) {
3145                         ret = -EIO;
3146                         btrfs_dev_stat_inc_and_print(device,
3147                                 BTRFS_DEV_STAT_FLUSH_ERRS);
3148                 }
3149 
3150                 /* drop the reference from the wait == 0 run */
3151                 bio_put(bio);
3152                 device->flush_bio = NULL;
3153 
3154                 return ret;
3155         }
3156 
3157         /*
3158          * one reference for us, and we leave it for the
3159          * caller
3160          */
3161         device->flush_bio = NULL;
3162         bio = btrfs_io_bio_alloc(GFP_NOFS, 0);
3163         if (!bio)
3164                 return -ENOMEM;
3165 
3166         bio->bi_end_io = btrfs_end_empty_barrier;
3167         bio->bi_bdev = device->bdev;
3168         init_completion(&device->flush_wait);
3169         bio->bi_private = &device->flush_wait;
3170         device->flush_bio = bio;
3171 
3172         bio_get(bio);
3173         btrfsic_submit_bio(WRITE_FLUSH, bio);
3174 
3175         return 0;
3176 }
3177 
3178 /*
3179  * send an empty flush down to each device in parallel,
3180  * then wait for them
3181  */
3182 static int barrier_all_devices(struct btrfs_fs_info *info)
3183 {
3184         struct list_head *head;
3185         struct btrfs_device *dev;
3186         int errors_send = 0;
3187         int errors_wait = 0;
3188         int ret;
3189 
3190         /* send down all the barriers */
3191         head = &info->fs_devices->devices;
3192         list_for_each_entry_rcu(dev, head, dev_list) {
3193                 if (!dev->bdev) {
3194                         errors_send++;
3195                         continue;
3196                 }
3197                 if (!dev->in_fs_metadata || !dev->writeable)
3198                         continue;
3199 
3200                 ret = write_dev_flush(dev, 0);
3201                 if (ret)
3202                         errors_send++;
3203         }
3204 
3205         /* wait for all the barriers */
3206         list_for_each_entry_rcu(dev, head, dev_list) {
3207                 if (!dev->bdev) {
3208                         errors_wait++;
3209                         continue;
3210                 }
3211                 if (!dev->in_fs_metadata || !dev->writeable)
3212                         continue;
3213 
3214                 ret = write_dev_flush(dev, 1);
3215                 if (ret)
3216                         errors_wait++;
3217         }
3218         if (errors_send > info->num_tolerated_disk_barrier_failures ||
3219             errors_wait > info->num_tolerated_disk_barrier_failures)
3220                 return -EIO;
3221         return 0;
3222 }
3223 
3224 int btrfs_calc_num_tolerated_disk_barrier_failures(
3225         struct btrfs_fs_info *fs_info)
3226 {
3227         struct btrfs_ioctl_space_info space;
3228         struct btrfs_space_info *sinfo;
3229         u64 types[] = {BTRFS_BLOCK_GROUP_DATA,
3230                        BTRFS_BLOCK_GROUP_SYSTEM,
3231                        BTRFS_BLOCK_GROUP_METADATA,
3232                        BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA};
3233         int num_types = 4;
3234         int i;
3235         int c;
3236         int num_tolerated_disk_barrier_failures =
3237                 (int)fs_info->fs_devices->num_devices;
3238 
3239         for (i = 0; i < num_types; i++) {
3240                 struct btrfs_space_info *tmp;
3241 
3242                 sinfo = NULL;
3243                 rcu_read_lock();
3244                 list_for_each_entry_rcu(tmp, &fs_info->space_info, list) {
3245                         if (tmp->flags == types[i]) {
3246                                 sinfo = tmp;
3247                                 break;
3248                         }
3249                 }
3250                 rcu_read_unlock();
3251 
3252                 if (!sinfo)
3253                         continue;
3254 
3255                 down_read(&sinfo->groups_sem);
3256                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
3257                         if (!list_empty(&sinfo->block_groups[c])) {
3258                                 u64 flags;
3259 
3260                                 btrfs_get_block_group_info(
3261                                         &sinfo->block_groups[c], &space);
3262                                 if (space.total_bytes == 0 ||
3263                                     space.used_bytes == 0)
3264                                         continue;
3265                                 flags = space.flags;
3266                                 /*
3267                                  * return
3268                                  * 0: if dup, single or RAID0 is configured for
3269                                  *    any of metadata, system or data, else
3270                                  * 1: if RAID5 is configured, or if RAID1 or
3271                                  *    RAID10 is configured and only two mirrors
3272                                  *    are used, else
3273                                  * 2: if RAID6 is configured, else
3274                                  * num_mirrors - 1: if RAID1 or RAID10 is
3275                                  *                  configured and more than
3276                                  *                  2 mirrors are used.
3277                                  */
3278                                 if (num_tolerated_disk_barrier_failures > 0 &&
3279                                     ((flags & (BTRFS_BLOCK_GROUP_DUP |
3280                                                BTRFS_BLOCK_GROUP_RAID0)) ||
3281                                      ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK)
3282                                       == 0)))
3283                                         num_tolerated_disk_barrier_failures = 0;
3284                                 else if (num_tolerated_disk_barrier_failures > 1) {
3285                                         if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3286                                             BTRFS_BLOCK_GROUP_RAID5 |
3287                                             BTRFS_BLOCK_GROUP_RAID10)) {
3288                                                 num_tolerated_disk_barrier_failures = 1;
3289                                         } else if (flags &
3290                                                    BTRFS_BLOCK_GROUP_RAID6) {
3291                                                 num_tolerated_disk_barrier_failures = 2;
3292                                         }
3293                                 }
3294                         }
3295                 }
3296                 up_read(&sinfo->groups_sem);
3297         }
3298 
3299         return num_tolerated_disk_barrier_failures;
3300 }
3301 
3302 static int write_all_supers(struct btrfs_root *root, int max_mirrors)
3303 {
3304         struct list_head *head;
3305         struct btrfs_device *dev;
3306         struct btrfs_super_block *sb;
3307         struct btrfs_dev_item *dev_item;
3308         int ret;
3309         int do_barriers;
3310         int max_errors;
3311         int total_errors = 0;
3312         u64 flags;
3313 
3314         max_errors = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
3315         do_barriers = !btrfs_test_opt(root, NOBARRIER);
3316         backup_super_roots(root->fs_info);
3317 
3318         sb = root->fs_info->super_for_commit;
3319         dev_item = &sb->dev_item;
3320 
3321         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
3322         head = &root->fs_info->fs_devices->devices;
3323 
3324         if (do_barriers) {
3325                 ret = barrier_all_devices(root->fs_info);
3326                 if (ret) {
3327                         mutex_unlock(
3328                                 &root->fs_info->fs_devices->device_list_mutex);
3329                         btrfs_error(root->fs_info, ret,
3330                                     "errors while submitting device barriers.");
3331                         return ret;
3332                 }
3333         }
3334 
3335         list_for_each_entry_rcu(dev, head, dev_list) {
3336                 if (!dev->bdev) {
3337                         total_errors++;
3338                         continue;
3339                 }
3340                 if (!dev->in_fs_metadata || !dev->writeable)
3341                         continue;
3342 
3343                 btrfs_set_stack_device_generation(dev_item, 0);
3344                 btrfs_set_stack_device_type(dev_item, dev->type);
3345                 btrfs_set_stack_device_id(dev_item, dev->devid);
3346                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
3347                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
3348                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
3349                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
3350                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
3351                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
3352                 memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
3353 
3354                 flags = btrfs_super_flags(sb);
3355                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
3356 
3357                 ret = write_dev_supers(dev, sb, do_barriers, 0, max_mirrors);
3358                 if (ret)
3359                         total_errors++;
3360         }
3361         if (total_errors > max_errors) {
3362                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
3363                        total_errors);
3364 
3365                 /* This shouldn't happen. FUA is masked off if unsupported */
3366                 BUG();
3367         }
3368 
3369         total_errors = 0;
3370         list_for_each_entry_rcu(dev, head, dev_list) {
3371                 if (!dev->bdev)
3372                         continue;
3373                 if (!dev->in_fs_metadata || !dev->writeable)
3374                         continue;
3375 
3376                 ret = write_dev_supers(dev, sb, do_barriers, 1, max_mirrors);
3377                 if (ret)
3378                         total_errors++;
3379         }
3380         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
3381         if (total_errors > max_errors) {
3382                 btrfs_error(root->fs_info, -EIO,
3383                             "%d errors while writing supers", total_errors);
3384                 return -EIO;
3385         }
3386         return 0;
3387 }
3388 
3389 int write_ctree_super(struct btrfs_trans_handle *trans,
3390                       struct btrfs_root *root, int max_mirrors)
3391 {
3392         int ret;
3393 
3394         ret = write_all_supers(root, max_mirrors);
3395         return ret;
3396 }
3397 
3398 /* Drop a fs root from the radix tree and free it. */
3399 void btrfs_drop_and_free_fs_root(struct btrfs_fs_info *fs_info,
3400                                   struct btrfs_root *root)
3401 {
3402         spin_lock(&fs_info->fs_roots_radix_lock);
3403         radix_tree_delete(&fs_info->fs_roots_radix,
3404                           (unsigned long)root->root_key.objectid);
3405         spin_unlock(&fs_info->fs_roots_radix_lock);
3406 
3407         if (btrfs_root_refs(&root->root_item) == 0)
3408                 synchronize_srcu(&fs_info->subvol_srcu);
3409 
3410         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
3411                 btrfs_free_log(NULL, root);
3412                 btrfs_free_log_root_tree(NULL, fs_info);
3413         }
3414 
3415         __btrfs_remove_free_space_cache(root->free_ino_pinned);
3416         __btrfs_remove_free_space_cache(root->free_ino_ctl);
3417         free_fs_root(root);
3418 }
3419 
3420 static void free_fs_root(struct btrfs_root *root)
3421 {
3422         iput(root->cache_inode);
3423         WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
3424         if (root->anon_dev)
3425                 free_anon_bdev(root->anon_dev);
3426         free_extent_buffer(root->node);
3427         free_extent_buffer(root->commit_root);
3428         kfree(root->free_ino_ctl);
3429         kfree(root->free_ino_pinned);
3430         kfree(root->name);
3431         btrfs_put_fs_root(root);
3432 }
3433 
3434 void btrfs_free_fs_root(struct btrfs_root *root)
3435 {
3436         free_fs_root(root);
3437 }
3438 
3439 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
3440 {
3441         u64 root_objectid = 0;
3442         struct btrfs_root *gang[8];
3443         int i;
3444         int ret;
3445 
3446         while (1) {
3447                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
3448                                              (void **)gang, root_objectid,
3449                                              ARRAY_SIZE(gang));
3450                 if (!ret)
3451                         break;
3452 
3453                 root_objectid = gang[ret - 1]->root_key.objectid + 1;
3454                 for (i = 0; i < ret; i++) {
3455                         int err;
3456 
3457                         root_objectid = gang[i]->root_key.objectid;
3458                         err = btrfs_orphan_cleanup(gang[i]);
3459                         if (err)
3460                                 return err;
3461                 }
3462                 root_objectid++;
3463         }
3464         return 0;
3465 }
3466 
3467 int btrfs_commit_super(struct btrfs_root *root)
3468 {
3469         struct btrfs_trans_handle *trans;
3470         int ret;
3471 
3472         mutex_lock(&root->fs_info->cleaner_mutex);
3473         btrfs_run_delayed_iputs(root);
3474         mutex_unlock(&root->fs_info->cleaner_mutex);
3475         wake_up_process(root->fs_info->cleaner_kthread);
3476 
3477         /* wait until ongoing cleanup work done */
3478         down_write(&root->fs_info->cleanup_work_sem);
3479         up_write(&root->fs_info->cleanup_work_sem);
3480 
3481         trans = btrfs_join_transaction(root);
3482         if (IS_ERR(trans))
3483                 return PTR_ERR(trans);
3484         ret = btrfs_commit_transaction(trans, root);
3485         if (ret)
3486                 return ret;
3487         /* run commit again to drop the original snapshot */
3488         trans = btrfs_join_transaction(root);
3489         if (IS_ERR(trans))
3490                 return PTR_ERR(trans);
3491         ret = btrfs_commit_transaction(trans, root);
3492         if (ret)
3493                 return ret;
3494         ret = btrfs_write_and_wait_transaction(NULL, root);
3495         if (ret) {
3496                 btrfs_error(root->fs_info, ret,
3497                             "Failed to sync btree inode to disk.");
3498                 return ret;
3499         }
3500 
3501         ret = write_ctree_super(NULL, root, 0);
3502         return ret;
3503 }
3504 
3505 int close_ctree(struct btrfs_root *root)
3506 {
3507         struct btrfs_fs_info *fs_info = root->fs_info;
3508         int ret;
3509 
3510         fs_info->closing = 1;
3511         smp_mb();
3512 
3513         /* pause restriper - we want to resume on mount */
3514         btrfs_pause_balance(fs_info);
3515 
3516         btrfs_dev_replace_suspend_for_unmount(fs_info);
3517 
3518         btrfs_scrub_cancel(fs_info);
3519 
3520         /* wait for any defraggers to finish */
3521         wait_event(fs_info->transaction_wait,
3522                    (atomic_read(&fs_info->defrag_running) == 0));
3523 
3524         /* clear out the rbtree of defraggable inodes */
3525         btrfs_cleanup_defrag_inodes(fs_info);
3526 
3527         if (!(fs_info->sb->s_flags & MS_RDONLY)) {
3528                 ret = btrfs_commit_super(root);
3529                 if (ret)
3530                         printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
3531         }
3532 
3533         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
3534                 btrfs_error_commit_super(root);
3535 
3536         btrfs_put_block_group_cache(fs_info);
3537 
3538         kthread_stop(fs_info->transaction_kthread);
3539         kthread_stop(fs_info->cleaner_kthread);
3540 
3541         fs_info->closing = 2;
3542         smp_mb();
3543 
3544         btrfs_free_qgroup_config(root->fs_info);
3545 
3546         if (percpu_counter_sum(&fs_info->delalloc_bytes)) {
3547                 printk(KERN_INFO "btrfs: at unmount delalloc count %lld\n",
3548                        percpu_counter_sum(&fs_info->delalloc_bytes));
3549         }
3550 
3551         btrfs_free_block_groups(fs_info);
3552 
3553         btrfs_stop_all_workers(fs_info);
3554 
3555         del_fs_roots(fs_info);
3556 
3557         free_root_pointers(fs_info, 1);
3558 
3559         iput(fs_info->btree_inode);
3560 
3561 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
3562         if (btrfs_test_opt(root, CHECK_INTEGRITY))
3563                 btrfsic_unmount(root, fs_info->fs_devices);
3564 #endif
3565 
3566         btrfs_close_devices(fs_info->fs_devices);
3567         btrfs_mapping_tree_free(&fs_info->mapping_tree);
3568 
3569         percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
3570         percpu_counter_destroy(&fs_info->delalloc_bytes);
3571         bdi_destroy(&fs_info->bdi);
3572         cleanup_srcu_struct(&fs_info->subvol_srcu);
3573 
3574         btrfs_free_stripe_hash_table(fs_info);
3575 
3576         return 0;
3577 }
3578 
3579 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
3580                           int atomic)
3581 {
3582         int ret;
3583         struct inode *btree_inode = buf->pages[0]->mapping->host;
3584 
3585         ret = extent_buffer_uptodate(buf);
3586         if (!ret)
3587                 return ret;
3588 
3589         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
3590                                     parent_transid, atomic);
3591         if (ret == -EAGAIN)
3592                 return ret;
3593         return !ret;
3594 }
3595 
3596 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
3597 {
3598         return set_extent_buffer_uptodate(buf);
3599 }
3600 
3601 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
3602 {
3603         struct btrfs_root *root = BTRFS_I(buf->pages[0]->mapping->host)->root;
3604         u64 transid = btrfs_header_generation(buf);
3605         int was_dirty;
3606 
3607         btrfs_assert_tree_locked(buf);
3608         if (transid != root->fs_info->generation)
3609                 WARN(1, KERN_CRIT "btrfs transid mismatch buffer %llu, "
3610                        "found %llu running %llu\n",
3611                         (unsigned long long)buf->start,
3612                         (unsigned long long)transid,
3613                         (unsigned long long)root->fs_info->generation);
3614         was_dirty = set_extent_buffer_dirty(buf);
3615         if (!was_dirty)
3616                 __percpu_counter_add(&root->fs_info->dirty_metadata_bytes,
3617                                      buf->len,
3618                                      root->fs_info->dirty_metadata_batch);
3619 }
3620 
3621 static void __btrfs_btree_balance_dirty(struct btrfs_root *root,
3622                                         int flush_delayed)
3623 {
3624         /*
3625          * looks as though older kernels can get into trouble with
3626          * this code, they end up stuck in balance_dirty_pages forever
3627          */
3628         int ret;
3629 
3630         if (current->flags & PF_MEMALLOC)
3631                 return;
3632 
3633         if (flush_delayed)
3634                 btrfs_balance_delayed_items(root);
3635 
3636         ret = percpu_counter_compare(&root->fs_info->dirty_metadata_bytes,
3637                                      BTRFS_DIRTY_METADATA_THRESH);
3638         if (ret > 0) {
3639                 balance_dirty_pages_ratelimited(
3640                                    root->fs_info->btree_inode->i_mapping);
3641         }
3642         return;
3643 }
3644 
3645 void btrfs_btree_balance_dirty(struct btrfs_root *root)
3646 {
3647         __btrfs_btree_balance_dirty(root, 1);
3648 }
3649 
3650 void btrfs_btree_balance_dirty_nodelay(struct btrfs_root *root)
3651 {
3652         __btrfs_btree_balance_dirty(root, 0);
3653 }
3654 
3655 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
3656 {
3657         struct btrfs_root *root = BTRFS_I(buf->pages[0]->mapping->host)->root;
3658         return btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
3659 }
3660 
3661 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
3662                               int read_only)
3663 {
3664         /*
3665          * Placeholder for checks
3666          */
3667         return 0;
3668 }
3669 
3670 static void btrfs_error_commit_super(struct btrfs_root *root)
3671 {
3672         mutex_lock(&root->fs_info->cleaner_mutex);
3673         btrfs_run_delayed_iputs(root);
3674         mutex_unlock(&root->fs_info->cleaner_mutex);
3675 
3676         down_write(&root->fs_info->cleanup_work_sem);
3677         up_write(&root->fs_info->cleanup_work_sem);
3678 
3679         /* cleanup FS via transaction */
3680         btrfs_cleanup_transaction(root);
3681 }
3682 
3683 static void btrfs_destroy_ordered_operations(struct btrfs_transaction *t,
3684                                              struct btrfs_root *root)
3685 {
3686         struct btrfs_inode *btrfs_inode;
3687         struct list_head splice;
3688 
3689         INIT_LIST_HEAD(&splice);
3690 
3691         mutex_lock(&root->fs_info->ordered_operations_mutex);
3692         spin_lock(&root->fs_info->ordered_root_lock);
3693 
3694         list_splice_init(&t->ordered_operations, &splice);
3695         while (!list_empty(&splice)) {
3696                 btrfs_inode = list_entry(splice.next, struct btrfs_inode,
3697                                          ordered_operations);
3698 
3699                 list_del_init(&btrfs_inode->ordered_operations);
3700                 spin_unlock(&root->fs_info->ordered_root_lock);
3701 
3702                 btrfs_invalidate_inodes(btrfs_inode->root);
3703 
3704                 spin_lock(&root->fs_info->ordered_root_lock);
3705         }
3706 
3707         spin_unlock(&root->fs_info->ordered_root_lock);
3708         mutex_unlock(&root->fs_info->ordered_operations_mutex);
3709 }
3710 
3711 static void btrfs_destroy_ordered_extents(struct btrfs_root *root)
3712 {
3713         struct btrfs_ordered_extent *ordered;
3714 
3715         spin_lock(&root->ordered_extent_lock);
3716         /*
3717          * This will just short circuit the ordered completion stuff which will
3718          * make sure the ordered extent gets properly cleaned up.
3719          */
3720         list_for_each_entry(ordered, &root->ordered_extents,
3721                             root_extent_list)
3722                 set_bit(BTRFS_ORDERED_IOERR, &ordered->flags);
3723         spin_unlock(&root->ordered_extent_lock);
3724 }
3725 
3726 static void btrfs_destroy_all_ordered_extents(struct btrfs_fs_info *fs_info)
3727 {
3728         struct btrfs_root *root;
3729         struct list_head splice;
3730 
3731         INIT_LIST_HEAD(&splice);
3732 
3733         spin_lock(&fs_info->ordered_root_lock);
3734         list_splice_init(&fs_info->ordered_roots, &splice);
3735         while (!list_empty(&splice)) {
3736                 root = list_first_entry(&splice, struct btrfs_root,
3737                                         ordered_root);
3738                 list_del_init(&root->ordered_root);
3739 
3740                 btrfs_destroy_ordered_extents(root);
3741 
3742                 cond_resched_lock(&fs_info->ordered_root_lock);
3743         }
3744         spin_unlock(&fs_info->ordered_root_lock);
3745 }
3746 
3747 int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
3748                                struct btrfs_root *root)
3749 {
3750         struct rb_node *node;
3751         struct btrfs_delayed_ref_root *delayed_refs;
3752         struct btrfs_delayed_ref_node *ref;
3753         int ret = 0;
3754 
3755         delayed_refs = &trans->delayed_refs;
3756 
3757         spin_lock(&delayed_refs->lock);
3758         if (delayed_refs->num_entries == 0) {
3759                 spin_unlock(&delayed_refs->lock);
3760                 printk(KERN_INFO "delayed_refs has NO entry\n");
3761                 return ret;
3762         }
3763 
3764         while ((node = rb_first(&delayed_refs->root)) != NULL) {
3765                 struct btrfs_delayed_ref_head *head = NULL;
3766                 bool pin_bytes = false;
3767 
3768                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
3769                 atomic_set(&ref->refs, 1);
3770                 if (btrfs_delayed_ref_is_head(ref)) {
3771 
3772                         head = btrfs_delayed_node_to_head(ref);
3773                         if (!mutex_trylock(&head->mutex)) {
3774                                 atomic_inc(&ref->refs);
3775                                 spin_unlock(&delayed_refs->lock);
3776 
3777                                 /* Need to wait for the delayed ref to run */
3778                                 mutex_lock(&head->mutex);
3779                                 mutex_unlock(&head->mutex);
3780                                 btrfs_put_delayed_ref(ref);
3781 
3782                                 spin_lock(&delayed_refs->lock);
3783                                 continue;
3784                         }
3785 
3786                         if (head->must_insert_reserved)
3787                                 pin_bytes = true;
3788                         btrfs_free_delayed_extent_op(head->extent_op);
3789                         delayed_refs->num_heads--;
3790                         if (list_empty(&head->cluster))
3791                                 delayed_refs->num_heads_ready--;
3792                         list_del_init(&head->cluster);
3793                 }
3794 
3795                 ref->in_tree = 0;
3796                 rb_erase(&ref->rb_node, &delayed_refs->root);
3797                 delayed_refs->num_entries--;
3798                 spin_unlock(&delayed_refs->lock);
3799                 if (head) {
3800                         if (pin_bytes)
3801                                 btrfs_pin_extent(root, ref->bytenr,
3802                                                  ref->num_bytes, 1);
3803                         mutex_unlock(&head->mutex);
3804                 }
3805                 btrfs_put_delayed_ref(ref);
3806 
3807                 cond_resched();
3808                 spin_lock(&delayed_refs->lock);
3809         }
3810 
3811         spin_unlock(&delayed_refs->lock);
3812 
3813         return ret;
3814 }
3815 
3816 static void btrfs_evict_pending_snapshots(struct btrfs_transaction *t)
3817 {
3818         struct btrfs_pending_snapshot *snapshot;
3819         struct list_head splice;
3820 
3821         INIT_LIST_HEAD(&splice);
3822 
3823         list_splice_init(&t->pending_snapshots, &splice);
3824 
3825         while (!list_empty(&splice)) {
3826                 snapshot = list_entry(splice.next,
3827                                       struct btrfs_pending_snapshot,
3828                                       list);
3829                 snapshot->error = -ECANCELED;
3830                 list_del_init(&snapshot->list);
3831         }
3832 }
3833 
3834 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
3835 {
3836         struct btrfs_inode *btrfs_inode;
3837         struct list_head splice;
3838 
3839         INIT_LIST_HEAD(&splice);
3840 
3841         spin_lock(&root->delalloc_lock);
3842         list_splice_init(&root->delalloc_inodes, &splice);
3843 
3844         while (!list_empty(&splice)) {
3845                 btrfs_inode = list_first_entry(&splice, struct btrfs_inode,
3846                                                delalloc_inodes);
3847 
3848                 list_del_init(&btrfs_inode->delalloc_inodes);
3849                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
3850                           &btrfs_inode->runtime_flags);
3851                 spin_unlock(&root->delalloc_lock);
3852 
3853                 btrfs_invalidate_inodes(btrfs_inode->root);
3854 
3855                 spin_lock(&root->delalloc_lock);
3856         }
3857 
3858         spin_unlock(&root->delalloc_lock);
3859 }
3860 
3861 static void btrfs_destroy_all_delalloc_inodes(struct btrfs_fs_info *fs_info)
3862 {
3863         struct btrfs_root *root;
3864         struct list_head splice;
3865 
3866         INIT_LIST_HEAD(&splice);
3867 
3868         spin_lock(&fs_info->delalloc_root_lock);
3869         list_splice_init(&fs_info->delalloc_roots, &splice);
3870         while (!list_empty(&splice)) {
3871                 root = list_first_entry(&splice, struct btrfs_root,
3872                                          delalloc_root);
3873                 list_del_init(&root->delalloc_root);
3874                 root = btrfs_grab_fs_root(root);
3875                 BUG_ON(!root);
3876                 spin_unlock(&fs_info->delalloc_root_lock);
3877 
3878                 btrfs_destroy_delalloc_inodes(root);
3879                 btrfs_put_fs_root(root);
3880 
3881                 spin_lock(&fs_info->delalloc_root_lock);
3882         }
3883         spin_unlock(&fs_info->delalloc_root_lock);
3884 }
3885 
3886 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
3887                                         struct extent_io_tree *dirty_pages,
3888                                         int mark)
3889 {
3890         int ret;
3891         struct extent_buffer *eb;
3892         u64 start = 0;
3893         u64 end;
3894 
3895         while (1) {
3896                 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
3897                                             mark, NULL);
3898                 if (ret)
3899                         break;
3900 
3901                 clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
3902                 while (start <= end) {
3903                         eb = btrfs_find_tree_block(root, start,
3904                                                    root->leafsize);
3905                         start += root->leafsize;
3906                         if (!eb)
3907                                 continue;
3908                         wait_on_extent_buffer_writeback(eb);
3909 
3910                         if (test_and_clear_bit(EXTENT_BUFFER_DIRTY,
3911                                                &eb->bflags))
3912                                 clear_extent_buffer_dirty(eb);
3913                         free_extent_buffer_stale(eb);
3914                 }
3915         }
3916 
3917         return ret;
3918 }
3919 
3920 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
3921                                        struct extent_io_tree *pinned_extents)
3922 {
3923         struct extent_io_tree *unpin;
3924         u64 start;
3925         u64 end;
3926         int ret;
3927         bool loop = true;
3928 
3929         unpin = pinned_extents;
3930 again:
3931         while (1) {
3932                 ret = find_first_extent_bit(unpin, 0, &start, &end,
3933                                             EXTENT_DIRTY, NULL);
3934                 if (ret)
3935                         break;
3936 
3937                 /* opt_discard */
3938                 if (btrfs_test_opt(root, DISCARD))
3939                         ret = btrfs_error_discard_extent(root, start,
3940                                                          end + 1 - start,
3941                                                          NULL);
3942 
3943                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
3944                 btrfs_error_unpin_extent_range(root, start, end);
3945                 cond_resched();
3946         }
3947 
3948         if (loop) {
3949                 if (unpin == &root->fs_info->freed_extents[0])
3950                         unpin = &root->fs_info->freed_extents[1];
3951                 else
3952                         unpin = &root->fs_info->freed_extents[0];
3953                 loop = false;
3954                 goto again;
3955         }
3956 
3957         return 0;
3958 }
3959 
3960 void btrfs_cleanup_one_transaction(struct btrfs_transaction *cur_trans,
3961                                    struct btrfs_root *root)
3962 {
3963         btrfs_destroy_delayed_refs(cur_trans, root);
3964         btrfs_block_rsv_release(root, &root->fs_info->trans_block_rsv,
3965                                 cur_trans->dirty_pages.dirty_bytes);
3966 
3967         cur_trans->state = TRANS_STATE_COMMIT_START;
3968         wake_up(&root->fs_info->transaction_blocked_wait);
3969 
3970         btrfs_evict_pending_snapshots(cur_trans);
3971 
3972         cur_trans->state = TRANS_STATE_UNBLOCKED;
3973         wake_up(&root->fs_info->transaction_wait);
3974 
3975         btrfs_destroy_delayed_inodes(root);
3976         btrfs_assert_delayed_root_empty(root);
3977 
3978         btrfs_destroy_marked_extents(root, &cur_trans->dirty_pages,
3979                                      EXTENT_DIRTY);
3980         btrfs_destroy_pinned_extent(root,
3981                                     root->fs_info->pinned_extents);
3982 
3983         cur_trans->state =TRANS_STATE_COMPLETED;
3984         wake_up(&cur_trans->commit_wait);
3985 
3986         /*
3987         memset(cur_trans, 0, sizeof(*cur_trans));
3988         kmem_cache_free(btrfs_transaction_cachep, cur_trans);
3989         */
3990 }
3991 
3992 static int btrfs_cleanup_transaction(struct btrfs_root *root)
3993 {
3994         struct btrfs_transaction *t;
3995         LIST_HEAD(list);
3996 
3997         mutex_lock(&root->fs_info->transaction_kthread_mutex);
3998 
3999         spin_lock(&root->fs_info->trans_lock);
4000         list_splice_init(&root->fs_info->trans_list, &list);
4001         root->fs_info->running_transaction = NULL;
4002         spin_unlock(&root->fs_info->trans_lock);
4003 
4004         while (!list_empty(&list)) {
4005                 t = list_entry(list.next, struct btrfs_transaction, list);
4006 
4007                 btrfs_destroy_ordered_operations(t, root);
4008 
4009                 btrfs_destroy_all_ordered_extents(root->fs_info);
4010 
4011                 btrfs_destroy_delayed_refs(t, root);
4012 
4013                 /*
4014                  *  FIXME: cleanup wait for commit
4015                  *  We needn't acquire the lock here, because we are during
4016                  *  the umount, there is no other task which will change it.
4017                  */
4018                 t->state = TRANS_STATE_COMMIT_START;
4019                 smp_mb();
4020                 if (waitqueue_active(&root->fs_info->transaction_blocked_wait))
4021                         wake_up(&root->fs_info->transaction_blocked_wait);
4022 
4023                 btrfs_evict_pending_snapshots(t);
4024 
4025                 t->state = TRANS_STATE_UNBLOCKED;
4026                 smp_mb();
4027                 if (waitqueue_active(&root->fs_info->transaction_wait))
4028                         wake_up(&root->fs_info->transaction_wait);
4029 
4030                 btrfs_destroy_delayed_inodes(root);
4031                 btrfs_assert_delayed_root_empty(root);
4032 
4033                 btrfs_destroy_all_delalloc_inodes(root->fs_info);
4034 
4035                 btrfs_destroy_marked_extents(root, &t->dirty_pages,
4036                                              EXTENT_DIRTY);
4037 
4038                 btrfs_destroy_pinned_extent(root,
4039                                             root->fs_info->pinned_extents);
4040 
4041                 t->state = TRANS_STATE_COMPLETED;
4042                 smp_mb();
4043                 if (waitqueue_active(&t->commit_wait))
4044                         wake_up(&t->commit_wait);
4045 
4046                 atomic_set(&t->use_count, 0);
4047                 list_del_init(&t->list);
4048                 memset(t, 0, sizeof(*t));
4049                 kmem_cache_free(btrfs_transaction_cachep, t);
4050         }
4051 
4052         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
4053 
4054         return 0;
4055 }
4056 
4057 static struct extent_io_ops btree_extent_io_ops = {
4058         .readpage_end_io_hook = btree_readpage_end_io_hook,
4059         .readpage_io_failed_hook = btree_io_failed_hook,
4060         .submit_bio_hook = btree_submit_bio_hook,
4061         /* note we're sharing with inode.c for the merge bio hook */
4062         .merge_bio_hook = btrfs_merge_bio_hook,
4063 };
4064 

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