dd71be8759394b30aedba74b40079d3f71f32369
[~shefty/rdma-dev.git] / fs / btrfs / disk-io.c
1 /*
2  * Copyright (C) 2007 Oracle.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18
19 #include <linux/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 <asm/unaligned.h>
34 #include "compat.h"
35 #include "ctree.h"
36 #include "disk-io.h"
37 #include "transaction.h"
38 #include "btrfs_inode.h"
39 #include "volumes.h"
40 #include "print-tree.h"
41 #include "async-thread.h"
42 #include "locking.h"
43 #include "tree-log.h"
44 #include "free-space-cache.h"
45 #include "inode-map.h"
46
47 static struct extent_io_ops btree_extent_io_ops;
48 static void end_workqueue_fn(struct btrfs_work *work);
49 static void free_fs_root(struct btrfs_root *root);
50 static void btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
51                                     int read_only);
52 static int btrfs_destroy_ordered_operations(struct btrfs_root *root);
53 static int btrfs_destroy_ordered_extents(struct btrfs_root *root);
54 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
55                                       struct btrfs_root *root);
56 static int btrfs_destroy_pending_snapshots(struct btrfs_transaction *t);
57 static int btrfs_destroy_delalloc_inodes(struct btrfs_root *root);
58 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
59                                         struct extent_io_tree *dirty_pages,
60                                         int mark);
61 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
62                                        struct extent_io_tree *pinned_extents);
63 static int btrfs_cleanup_transaction(struct btrfs_root *root);
64
65 /*
66  * end_io_wq structs are used to do processing in task context when an IO is
67  * complete.  This is used during reads to verify checksums, and it is used
68  * by writes to insert metadata for new file extents after IO is complete.
69  */
70 struct end_io_wq {
71         struct bio *bio;
72         bio_end_io_t *end_io;
73         void *private;
74         struct btrfs_fs_info *info;
75         int error;
76         int metadata;
77         struct list_head list;
78         struct btrfs_work work;
79 };
80
81 /*
82  * async submit bios are used to offload expensive checksumming
83  * onto the worker threads.  They checksum file and metadata bios
84  * just before they are sent down the IO stack.
85  */
86 struct async_submit_bio {
87         struct inode *inode;
88         struct bio *bio;
89         struct list_head list;
90         extent_submit_bio_hook_t *submit_bio_start;
91         extent_submit_bio_hook_t *submit_bio_done;
92         int rw;
93         int mirror_num;
94         unsigned long bio_flags;
95         /*
96          * bio_offset is optional, can be used if the pages in the bio
97          * can't tell us where in the file the bio should go
98          */
99         u64 bio_offset;
100         struct btrfs_work work;
101 };
102
103 /*
104  * Lockdep class keys for extent_buffer->lock's in this root.  For a given
105  * eb, the lockdep key is determined by the btrfs_root it belongs to and
106  * the level the eb occupies in the tree.
107  *
108  * Different roots are used for different purposes and may nest inside each
109  * other and they require separate keysets.  As lockdep keys should be
110  * static, assign keysets according to the purpose of the root as indicated
111  * by btrfs_root->objectid.  This ensures that all special purpose roots
112  * have separate keysets.
113  *
114  * Lock-nesting across peer nodes is always done with the immediate parent
115  * node locked thus preventing deadlock.  As lockdep doesn't know this, use
116  * subclass to avoid triggering lockdep warning in such cases.
117  *
118  * The key is set by the readpage_end_io_hook after the buffer has passed
119  * csum validation but before the pages are unlocked.  It is also set by
120  * btrfs_init_new_buffer on freshly allocated blocks.
121  *
122  * We also add a check to make sure the highest level of the tree is the
123  * same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this code
124  * needs update as well.
125  */
126 #ifdef CONFIG_DEBUG_LOCK_ALLOC
127 # if BTRFS_MAX_LEVEL != 8
128 #  error
129 # endif
130
131 static struct btrfs_lockdep_keyset {
132         u64                     id;             /* root objectid */
133         const char              *name_stem;     /* lock name stem */
134         char                    names[BTRFS_MAX_LEVEL + 1][20];
135         struct lock_class_key   keys[BTRFS_MAX_LEVEL + 1];
136 } btrfs_lockdep_keysets[] = {
137         { .id = BTRFS_ROOT_TREE_OBJECTID,       .name_stem = "root"     },
138         { .id = BTRFS_EXTENT_TREE_OBJECTID,     .name_stem = "extent"   },
139         { .id = BTRFS_CHUNK_TREE_OBJECTID,      .name_stem = "chunk"    },
140         { .id = BTRFS_DEV_TREE_OBJECTID,        .name_stem = "dev"      },
141         { .id = BTRFS_FS_TREE_OBJECTID,         .name_stem = "fs"       },
142         { .id = BTRFS_CSUM_TREE_OBJECTID,       .name_stem = "csum"     },
143         { .id = BTRFS_ORPHAN_OBJECTID,          .name_stem = "orphan"   },
144         { .id = BTRFS_TREE_LOG_OBJECTID,        .name_stem = "log"      },
145         { .id = BTRFS_TREE_RELOC_OBJECTID,      .name_stem = "treloc"   },
146         { .id = BTRFS_DATA_RELOC_TREE_OBJECTID, .name_stem = "dreloc"   },
147         { .id = 0,                              .name_stem = "tree"     },
148 };
149
150 void __init btrfs_init_lockdep(void)
151 {
152         int i, j;
153
154         /* initialize lockdep class names */
155         for (i = 0; i < ARRAY_SIZE(btrfs_lockdep_keysets); i++) {
156                 struct btrfs_lockdep_keyset *ks = &btrfs_lockdep_keysets[i];
157
158                 for (j = 0; j < ARRAY_SIZE(ks->names); j++)
159                         snprintf(ks->names[j], sizeof(ks->names[j]),
160                                  "btrfs-%s-%02d", ks->name_stem, j);
161         }
162 }
163
164 void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb,
165                                     int level)
166 {
167         struct btrfs_lockdep_keyset *ks;
168
169         BUG_ON(level >= ARRAY_SIZE(ks->keys));
170
171         /* find the matching keyset, id 0 is the default entry */
172         for (ks = btrfs_lockdep_keysets; ks->id; ks++)
173                 if (ks->id == objectid)
174                         break;
175
176         lockdep_set_class_and_name(&eb->lock,
177                                    &ks->keys[level], ks->names[level]);
178 }
179
180 #endif
181
182 /*
183  * extents on the btree inode are pretty simple, there's one extent
184  * that covers the entire device
185  */
186 static struct extent_map *btree_get_extent(struct inode *inode,
187                 struct page *page, size_t pg_offset, u64 start, u64 len,
188                 int create)
189 {
190         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
191         struct extent_map *em;
192         int ret;
193
194         read_lock(&em_tree->lock);
195         em = lookup_extent_mapping(em_tree, start, len);
196         if (em) {
197                 em->bdev =
198                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
199                 read_unlock(&em_tree->lock);
200                 goto out;
201         }
202         read_unlock(&em_tree->lock);
203
204         em = alloc_extent_map();
205         if (!em) {
206                 em = ERR_PTR(-ENOMEM);
207                 goto out;
208         }
209         em->start = 0;
210         em->len = (u64)-1;
211         em->block_len = (u64)-1;
212         em->block_start = 0;
213         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
214
215         write_lock(&em_tree->lock);
216         ret = add_extent_mapping(em_tree, em);
217         if (ret == -EEXIST) {
218                 u64 failed_start = em->start;
219                 u64 failed_len = em->len;
220
221                 free_extent_map(em);
222                 em = lookup_extent_mapping(em_tree, start, len);
223                 if (em) {
224                         ret = 0;
225                 } else {
226                         em = lookup_extent_mapping(em_tree, failed_start,
227                                                    failed_len);
228                         ret = -EIO;
229                 }
230         } else if (ret) {
231                 free_extent_map(em);
232                 em = NULL;
233         }
234         write_unlock(&em_tree->lock);
235
236         if (ret)
237                 em = ERR_PTR(ret);
238 out:
239         return em;
240 }
241
242 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
243 {
244         return crc32c(seed, data, len);
245 }
246
247 void btrfs_csum_final(u32 crc, char *result)
248 {
249         put_unaligned_le32(~crc, result);
250 }
251
252 /*
253  * compute the csum for a btree block, and either verify it or write it
254  * into the csum field of the block.
255  */
256 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
257                            int verify)
258 {
259         u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
260         char *result = NULL;
261         unsigned long len;
262         unsigned long cur_len;
263         unsigned long offset = BTRFS_CSUM_SIZE;
264         char *kaddr;
265         unsigned long map_start;
266         unsigned long map_len;
267         int err;
268         u32 crc = ~(u32)0;
269         unsigned long inline_result;
270
271         len = buf->len - offset;
272         while (len > 0) {
273                 err = map_private_extent_buffer(buf, offset, 32,
274                                         &kaddr, &map_start, &map_len);
275                 if (err)
276                         return 1;
277                 cur_len = min(len, map_len - (offset - map_start));
278                 crc = btrfs_csum_data(root, kaddr + offset - map_start,
279                                       crc, cur_len);
280                 len -= cur_len;
281                 offset += cur_len;
282         }
283         if (csum_size > sizeof(inline_result)) {
284                 result = kzalloc(csum_size * sizeof(char), GFP_NOFS);
285                 if (!result)
286                         return 1;
287         } else {
288                 result = (char *)&inline_result;
289         }
290
291         btrfs_csum_final(crc, result);
292
293         if (verify) {
294                 if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
295                         u32 val;
296                         u32 found = 0;
297                         memcpy(&found, result, csum_size);
298
299                         read_extent_buffer(buf, &val, 0, csum_size);
300                         printk_ratelimited(KERN_INFO "btrfs: %s checksum verify "
301                                        "failed on %llu wanted %X found %X "
302                                        "level %d\n",
303                                        root->fs_info->sb->s_id,
304                                        (unsigned long long)buf->start, val, found,
305                                        btrfs_header_level(buf));
306                         if (result != (char *)&inline_result)
307                                 kfree(result);
308                         return 1;
309                 }
310         } else {
311                 write_extent_buffer(buf, result, 0, csum_size);
312         }
313         if (result != (char *)&inline_result)
314                 kfree(result);
315         return 0;
316 }
317
318 /*
319  * we can't consider a given block up to date unless the transid of the
320  * block matches the transid in the parent node's pointer.  This is how we
321  * detect blocks that either didn't get written at all or got written
322  * in the wrong place.
323  */
324 static int verify_parent_transid(struct extent_io_tree *io_tree,
325                                  struct extent_buffer *eb, u64 parent_transid)
326 {
327         struct extent_state *cached_state = NULL;
328         int ret;
329
330         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
331                 return 0;
332
333         lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
334                          0, &cached_state, GFP_NOFS);
335         if (extent_buffer_uptodate(io_tree, eb, cached_state) &&
336             btrfs_header_generation(eb) == parent_transid) {
337                 ret = 0;
338                 goto out;
339         }
340         printk_ratelimited("parent transid verify failed on %llu wanted %llu "
341                        "found %llu\n",
342                        (unsigned long long)eb->start,
343                        (unsigned long long)parent_transid,
344                        (unsigned long long)btrfs_header_generation(eb));
345         ret = 1;
346         clear_extent_buffer_uptodate(io_tree, eb, &cached_state);
347 out:
348         unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
349                              &cached_state, GFP_NOFS);
350         return ret;
351 }
352
353 /*
354  * helper to read a given tree block, doing retries as required when
355  * the checksums don't match and we have alternate mirrors to try.
356  */
357 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
358                                           struct extent_buffer *eb,
359                                           u64 start, u64 parent_transid)
360 {
361         struct extent_io_tree *io_tree;
362         int ret;
363         int num_copies = 0;
364         int mirror_num = 0;
365
366         clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
367         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
368         while (1) {
369                 ret = read_extent_buffer_pages(io_tree, eb, start,
370                                                WAIT_COMPLETE,
371                                                btree_get_extent, mirror_num);
372                 if (!ret &&
373                     !verify_parent_transid(io_tree, eb, parent_transid))
374                         return ret;
375
376                 /*
377                  * This buffer's crc is fine, but its contents are corrupted, so
378                  * there is no reason to read the other copies, they won't be
379                  * any less wrong.
380                  */
381                 if (test_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags))
382                         return ret;
383
384                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
385                                               eb->start, eb->len);
386                 if (num_copies == 1)
387                         return ret;
388
389                 mirror_num++;
390                 if (mirror_num > num_copies)
391                         return ret;
392         }
393         return -EIO;
394 }
395
396 /*
397  * checksum a dirty tree block before IO.  This has extra checks to make sure
398  * we only fill in the checksum field in the first page of a multi-page block
399  */
400
401 static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
402 {
403         struct extent_io_tree *tree;
404         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
405         u64 found_start;
406         unsigned long len;
407         struct extent_buffer *eb;
408         int ret;
409
410         tree = &BTRFS_I(page->mapping->host)->io_tree;
411
412         if (page->private == EXTENT_PAGE_PRIVATE) {
413                 WARN_ON(1);
414                 goto out;
415         }
416         if (!page->private) {
417                 WARN_ON(1);
418                 goto out;
419         }
420         len = page->private >> 2;
421         WARN_ON(len == 0);
422
423         eb = alloc_extent_buffer(tree, start, len, page);
424         if (eb == NULL) {
425                 WARN_ON(1);
426                 goto out;
427         }
428         ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE,
429                                              btrfs_header_generation(eb));
430         BUG_ON(ret);
431         WARN_ON(!btrfs_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN));
432
433         found_start = btrfs_header_bytenr(eb);
434         if (found_start != start) {
435                 WARN_ON(1);
436                 goto err;
437         }
438         if (eb->first_page != page) {
439                 WARN_ON(1);
440                 goto err;
441         }
442         if (!PageUptodate(page)) {
443                 WARN_ON(1);
444                 goto err;
445         }
446         csum_tree_block(root, eb, 0);
447 err:
448         free_extent_buffer(eb);
449 out:
450         return 0;
451 }
452
453 static int check_tree_block_fsid(struct btrfs_root *root,
454                                  struct extent_buffer *eb)
455 {
456         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
457         u8 fsid[BTRFS_UUID_SIZE];
458         int ret = 1;
459
460         read_extent_buffer(eb, fsid, (unsigned long)btrfs_header_fsid(eb),
461                            BTRFS_FSID_SIZE);
462         while (fs_devices) {
463                 if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
464                         ret = 0;
465                         break;
466                 }
467                 fs_devices = fs_devices->seed;
468         }
469         return ret;
470 }
471
472 #define CORRUPT(reason, eb, root, slot)                         \
473         printk(KERN_CRIT "btrfs: corrupt leaf, %s: block=%llu," \
474                "root=%llu, slot=%d\n", reason,                  \
475                (unsigned long long)btrfs_header_bytenr(eb),     \
476                (unsigned long long)root->objectid, slot)
477
478 static noinline int check_leaf(struct btrfs_root *root,
479                                struct extent_buffer *leaf)
480 {
481         struct btrfs_key key;
482         struct btrfs_key leaf_key;
483         u32 nritems = btrfs_header_nritems(leaf);
484         int slot;
485
486         if (nritems == 0)
487                 return 0;
488
489         /* Check the 0 item */
490         if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=
491             BTRFS_LEAF_DATA_SIZE(root)) {
492                 CORRUPT("invalid item offset size pair", leaf, root, 0);
493                 return -EIO;
494         }
495
496         /*
497          * Check to make sure each items keys are in the correct order and their
498          * offsets make sense.  We only have to loop through nritems-1 because
499          * we check the current slot against the next slot, which verifies the
500          * next slot's offset+size makes sense and that the current's slot
501          * offset is correct.
502          */
503         for (slot = 0; slot < nritems - 1; slot++) {
504                 btrfs_item_key_to_cpu(leaf, &leaf_key, slot);
505                 btrfs_item_key_to_cpu(leaf, &key, slot + 1);
506
507                 /* Make sure the keys are in the right order */
508                 if (btrfs_comp_cpu_keys(&leaf_key, &key) >= 0) {
509                         CORRUPT("bad key order", leaf, root, slot);
510                         return -EIO;
511                 }
512
513                 /*
514                  * Make sure the offset and ends are right, remember that the
515                  * item data starts at the end of the leaf and grows towards the
516                  * front.
517                  */
518                 if (btrfs_item_offset_nr(leaf, slot) !=
519                         btrfs_item_end_nr(leaf, slot + 1)) {
520                         CORRUPT("slot offset bad", leaf, root, slot);
521                         return -EIO;
522                 }
523
524                 /*
525                  * Check to make sure that we don't point outside of the leaf,
526                  * just incase all the items are consistent to eachother, but
527                  * all point outside of the leaf.
528                  */
529                 if (btrfs_item_end_nr(leaf, slot) >
530                     BTRFS_LEAF_DATA_SIZE(root)) {
531                         CORRUPT("slot end outside of leaf", leaf, root, slot);
532                         return -EIO;
533                 }
534         }
535
536         return 0;
537 }
538
539 static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
540                                struct extent_state *state)
541 {
542         struct extent_io_tree *tree;
543         u64 found_start;
544         int found_level;
545         unsigned long len;
546         struct extent_buffer *eb;
547         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
548         int ret = 0;
549
550         tree = &BTRFS_I(page->mapping->host)->io_tree;
551         if (page->private == EXTENT_PAGE_PRIVATE)
552                 goto out;
553         if (!page->private)
554                 goto out;
555
556         len = page->private >> 2;
557         WARN_ON(len == 0);
558
559         eb = alloc_extent_buffer(tree, start, len, page);
560         if (eb == NULL) {
561                 ret = -EIO;
562                 goto out;
563         }
564
565         found_start = btrfs_header_bytenr(eb);
566         if (found_start != start) {
567                 printk_ratelimited(KERN_INFO "btrfs bad tree block start "
568                                "%llu %llu\n",
569                                (unsigned long long)found_start,
570                                (unsigned long long)eb->start);
571                 ret = -EIO;
572                 goto err;
573         }
574         if (eb->first_page != page) {
575                 printk(KERN_INFO "btrfs bad first page %lu %lu\n",
576                        eb->first_page->index, page->index);
577                 WARN_ON(1);
578                 ret = -EIO;
579                 goto err;
580         }
581         if (check_tree_block_fsid(root, eb)) {
582                 printk_ratelimited(KERN_INFO "btrfs bad fsid on block %llu\n",
583                                (unsigned long long)eb->start);
584                 ret = -EIO;
585                 goto err;
586         }
587         found_level = btrfs_header_level(eb);
588
589         btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb),
590                                        eb, found_level);
591
592         ret = csum_tree_block(root, eb, 1);
593         if (ret) {
594                 ret = -EIO;
595                 goto err;
596         }
597
598         /*
599          * If this is a leaf block and it is corrupt, set the corrupt bit so
600          * that we don't try and read the other copies of this block, just
601          * return -EIO.
602          */
603         if (found_level == 0 && check_leaf(root, eb)) {
604                 set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
605                 ret = -EIO;
606         }
607
608         end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
609         end = eb->start + end - 1;
610 err:
611         if (test_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags)) {
612                 clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags);
613                 btree_readahead_hook(root, eb, eb->start, ret);
614         }
615
616         free_extent_buffer(eb);
617 out:
618         return ret;
619 }
620
621 static int btree_io_failed_hook(struct bio *failed_bio,
622                          struct page *page, u64 start, u64 end,
623                          int mirror_num, struct extent_state *state)
624 {
625         struct extent_io_tree *tree;
626         unsigned long len;
627         struct extent_buffer *eb;
628         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
629
630         tree = &BTRFS_I(page->mapping->host)->io_tree;
631         if (page->private == EXTENT_PAGE_PRIVATE)
632                 goto out;
633         if (!page->private)
634                 goto out;
635
636         len = page->private >> 2;
637         WARN_ON(len == 0);
638
639         eb = alloc_extent_buffer(tree, start, len, page);
640         if (eb == NULL)
641                 goto out;
642
643         if (test_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags)) {
644                 clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags);
645                 btree_readahead_hook(root, eb, eb->start, -EIO);
646         }
647         free_extent_buffer(eb);
648
649 out:
650         return -EIO;    /* we fixed nothing */
651 }
652
653 static void end_workqueue_bio(struct bio *bio, int err)
654 {
655         struct end_io_wq *end_io_wq = bio->bi_private;
656         struct btrfs_fs_info *fs_info;
657
658         fs_info = end_io_wq->info;
659         end_io_wq->error = err;
660         end_io_wq->work.func = end_workqueue_fn;
661         end_io_wq->work.flags = 0;
662
663         if (bio->bi_rw & REQ_WRITE) {
664                 if (end_io_wq->metadata == 1)
665                         btrfs_queue_worker(&fs_info->endio_meta_write_workers,
666                                            &end_io_wq->work);
667                 else if (end_io_wq->metadata == 2)
668                         btrfs_queue_worker(&fs_info->endio_freespace_worker,
669                                            &end_io_wq->work);
670                 else
671                         btrfs_queue_worker(&fs_info->endio_write_workers,
672                                            &end_io_wq->work);
673         } else {
674                 if (end_io_wq->metadata)
675                         btrfs_queue_worker(&fs_info->endio_meta_workers,
676                                            &end_io_wq->work);
677                 else
678                         btrfs_queue_worker(&fs_info->endio_workers,
679                                            &end_io_wq->work);
680         }
681 }
682
683 /*
684  * For the metadata arg you want
685  *
686  * 0 - if data
687  * 1 - if normal metadta
688  * 2 - if writing to the free space cache area
689  */
690 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
691                         int metadata)
692 {
693         struct end_io_wq *end_io_wq;
694         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
695         if (!end_io_wq)
696                 return -ENOMEM;
697
698         end_io_wq->private = bio->bi_private;
699         end_io_wq->end_io = bio->bi_end_io;
700         end_io_wq->info = info;
701         end_io_wq->error = 0;
702         end_io_wq->bio = bio;
703         end_io_wq->metadata = metadata;
704
705         bio->bi_private = end_io_wq;
706         bio->bi_end_io = end_workqueue_bio;
707         return 0;
708 }
709
710 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
711 {
712         unsigned long limit = min_t(unsigned long,
713                                     info->workers.max_workers,
714                                     info->fs_devices->open_devices);
715         return 256 * limit;
716 }
717
718 static void run_one_async_start(struct btrfs_work *work)
719 {
720         struct async_submit_bio *async;
721
722         async = container_of(work, struct  async_submit_bio, work);
723         async->submit_bio_start(async->inode, async->rw, async->bio,
724                                async->mirror_num, async->bio_flags,
725                                async->bio_offset);
726 }
727
728 static void run_one_async_done(struct btrfs_work *work)
729 {
730         struct btrfs_fs_info *fs_info;
731         struct async_submit_bio *async;
732         int limit;
733
734         async = container_of(work, struct  async_submit_bio, work);
735         fs_info = BTRFS_I(async->inode)->root->fs_info;
736
737         limit = btrfs_async_submit_limit(fs_info);
738         limit = limit * 2 / 3;
739
740         atomic_dec(&fs_info->nr_async_submits);
741
742         if (atomic_read(&fs_info->nr_async_submits) < limit &&
743             waitqueue_active(&fs_info->async_submit_wait))
744                 wake_up(&fs_info->async_submit_wait);
745
746         async->submit_bio_done(async->inode, async->rw, async->bio,
747                                async->mirror_num, async->bio_flags,
748                                async->bio_offset);
749 }
750
751 static void run_one_async_free(struct btrfs_work *work)
752 {
753         struct async_submit_bio *async;
754
755         async = container_of(work, struct  async_submit_bio, work);
756         kfree(async);
757 }
758
759 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
760                         int rw, struct bio *bio, int mirror_num,
761                         unsigned long bio_flags,
762                         u64 bio_offset,
763                         extent_submit_bio_hook_t *submit_bio_start,
764                         extent_submit_bio_hook_t *submit_bio_done)
765 {
766         struct async_submit_bio *async;
767
768         async = kmalloc(sizeof(*async), GFP_NOFS);
769         if (!async)
770                 return -ENOMEM;
771
772         async->inode = inode;
773         async->rw = rw;
774         async->bio = bio;
775         async->mirror_num = mirror_num;
776         async->submit_bio_start = submit_bio_start;
777         async->submit_bio_done = submit_bio_done;
778
779         async->work.func = run_one_async_start;
780         async->work.ordered_func = run_one_async_done;
781         async->work.ordered_free = run_one_async_free;
782
783         async->work.flags = 0;
784         async->bio_flags = bio_flags;
785         async->bio_offset = bio_offset;
786
787         atomic_inc(&fs_info->nr_async_submits);
788
789         if (rw & REQ_SYNC)
790                 btrfs_set_work_high_prio(&async->work);
791
792         btrfs_queue_worker(&fs_info->workers, &async->work);
793
794         while (atomic_read(&fs_info->async_submit_draining) &&
795               atomic_read(&fs_info->nr_async_submits)) {
796                 wait_event(fs_info->async_submit_wait,
797                            (atomic_read(&fs_info->nr_async_submits) == 0));
798         }
799
800         return 0;
801 }
802
803 static int btree_csum_one_bio(struct bio *bio)
804 {
805         struct bio_vec *bvec = bio->bi_io_vec;
806         int bio_index = 0;
807         struct btrfs_root *root;
808
809         WARN_ON(bio->bi_vcnt <= 0);
810         while (bio_index < bio->bi_vcnt) {
811                 root = BTRFS_I(bvec->bv_page->mapping->host)->root;
812                 csum_dirty_buffer(root, bvec->bv_page);
813                 bio_index++;
814                 bvec++;
815         }
816         return 0;
817 }
818
819 static int __btree_submit_bio_start(struct inode *inode, int rw,
820                                     struct bio *bio, int mirror_num,
821                                     unsigned long bio_flags,
822                                     u64 bio_offset)
823 {
824         /*
825          * when we're called for a write, we're already in the async
826          * submission context.  Just jump into btrfs_map_bio
827          */
828         btree_csum_one_bio(bio);
829         return 0;
830 }
831
832 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
833                                  int mirror_num, unsigned long bio_flags,
834                                  u64 bio_offset)
835 {
836         /*
837          * when we're called for a write, we're already in the async
838          * submission context.  Just jump into btrfs_map_bio
839          */
840         return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
841 }
842
843 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
844                                  int mirror_num, unsigned long bio_flags,
845                                  u64 bio_offset)
846 {
847         int ret;
848
849         ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
850                                           bio, 1);
851         BUG_ON(ret);
852
853         if (!(rw & REQ_WRITE)) {
854                 /*
855                  * called for a read, do the setup so that checksum validation
856                  * can happen in the async kernel threads
857                  */
858                 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
859                                      mirror_num, 0);
860         }
861
862         /*
863          * kthread helpers are used to submit writes so that checksumming
864          * can happen in parallel across all CPUs
865          */
866         return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
867                                    inode, rw, bio, mirror_num, 0,
868                                    bio_offset,
869                                    __btree_submit_bio_start,
870                                    __btree_submit_bio_done);
871 }
872
873 #ifdef CONFIG_MIGRATION
874 static int btree_migratepage(struct address_space *mapping,
875                         struct page *newpage, struct page *page)
876 {
877         /*
878          * we can't safely write a btree page from here,
879          * we haven't done the locking hook
880          */
881         if (PageDirty(page))
882                 return -EAGAIN;
883         /*
884          * Buffers may be managed in a filesystem specific way.
885          * We must have no buffers or drop them.
886          */
887         if (page_has_private(page) &&
888             !try_to_release_page(page, GFP_KERNEL))
889                 return -EAGAIN;
890         return migrate_page(mapping, newpage, page);
891 }
892 #endif
893
894 static int btree_writepage(struct page *page, struct writeback_control *wbc)
895 {
896         struct extent_io_tree *tree;
897         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
898         struct extent_buffer *eb;
899         int was_dirty;
900
901         tree = &BTRFS_I(page->mapping->host)->io_tree;
902         if (!(current->flags & PF_MEMALLOC)) {
903                 return extent_write_full_page(tree, page,
904                                               btree_get_extent, wbc);
905         }
906
907         redirty_page_for_writepage(wbc, page);
908         eb = btrfs_find_tree_block(root, page_offset(page), PAGE_CACHE_SIZE);
909         WARN_ON(!eb);
910
911         was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
912         if (!was_dirty) {
913                 spin_lock(&root->fs_info->delalloc_lock);
914                 root->fs_info->dirty_metadata_bytes += PAGE_CACHE_SIZE;
915                 spin_unlock(&root->fs_info->delalloc_lock);
916         }
917         free_extent_buffer(eb);
918
919         unlock_page(page);
920         return 0;
921 }
922
923 static int btree_writepages(struct address_space *mapping,
924                             struct writeback_control *wbc)
925 {
926         struct extent_io_tree *tree;
927         tree = &BTRFS_I(mapping->host)->io_tree;
928         if (wbc->sync_mode == WB_SYNC_NONE) {
929                 struct btrfs_root *root = BTRFS_I(mapping->host)->root;
930                 u64 num_dirty;
931                 unsigned long thresh = 32 * 1024 * 1024;
932
933                 if (wbc->for_kupdate)
934                         return 0;
935
936                 /* this is a bit racy, but that's ok */
937                 num_dirty = root->fs_info->dirty_metadata_bytes;
938                 if (num_dirty < thresh)
939                         return 0;
940         }
941         return extent_writepages(tree, mapping, btree_get_extent, wbc);
942 }
943
944 static int btree_readpage(struct file *file, struct page *page)
945 {
946         struct extent_io_tree *tree;
947         tree = &BTRFS_I(page->mapping->host)->io_tree;
948         return extent_read_full_page(tree, page, btree_get_extent, 0);
949 }
950
951 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
952 {
953         struct extent_io_tree *tree;
954         struct extent_map_tree *map;
955         int ret;
956
957         if (PageWriteback(page) || PageDirty(page))
958                 return 0;
959
960         tree = &BTRFS_I(page->mapping->host)->io_tree;
961         map = &BTRFS_I(page->mapping->host)->extent_tree;
962
963         ret = try_release_extent_state(map, tree, page, gfp_flags);
964         if (!ret)
965                 return 0;
966
967         ret = try_release_extent_buffer(tree, page);
968         if (ret == 1) {
969                 ClearPagePrivate(page);
970                 set_page_private(page, 0);
971                 page_cache_release(page);
972         }
973
974         return ret;
975 }
976
977 static void btree_invalidatepage(struct page *page, unsigned long offset)
978 {
979         struct extent_io_tree *tree;
980         tree = &BTRFS_I(page->mapping->host)->io_tree;
981         extent_invalidatepage(tree, page, offset);
982         btree_releasepage(page, GFP_NOFS);
983         if (PagePrivate(page)) {
984                 printk(KERN_WARNING "btrfs warning page private not zero "
985                        "on page %llu\n", (unsigned long long)page_offset(page));
986                 ClearPagePrivate(page);
987                 set_page_private(page, 0);
988                 page_cache_release(page);
989         }
990 }
991
992 static const struct address_space_operations btree_aops = {
993         .readpage       = btree_readpage,
994         .writepage      = btree_writepage,
995         .writepages     = btree_writepages,
996         .releasepage    = btree_releasepage,
997         .invalidatepage = btree_invalidatepage,
998 #ifdef CONFIG_MIGRATION
999         .migratepage    = btree_migratepage,
1000 #endif
1001 };
1002
1003 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
1004                          u64 parent_transid)
1005 {
1006         struct extent_buffer *buf = NULL;
1007         struct inode *btree_inode = root->fs_info->btree_inode;
1008         int ret = 0;
1009
1010         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1011         if (!buf)
1012                 return 0;
1013         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
1014                                  buf, 0, WAIT_NONE, btree_get_extent, 0);
1015         free_extent_buffer(buf);
1016         return ret;
1017 }
1018
1019 int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr, u32 blocksize,
1020                          int mirror_num, struct extent_buffer **eb)
1021 {
1022         struct extent_buffer *buf = NULL;
1023         struct inode *btree_inode = root->fs_info->btree_inode;
1024         struct extent_io_tree *io_tree = &BTRFS_I(btree_inode)->io_tree;
1025         int ret;
1026
1027         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1028         if (!buf)
1029                 return 0;
1030
1031         set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
1032
1033         ret = read_extent_buffer_pages(io_tree, buf, 0, WAIT_PAGE_LOCK,
1034                                        btree_get_extent, mirror_num);
1035         if (ret) {
1036                 free_extent_buffer(buf);
1037                 return ret;
1038         }
1039
1040         if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags)) {
1041                 free_extent_buffer(buf);
1042                 return -EIO;
1043         } else if (extent_buffer_uptodate(io_tree, buf, NULL)) {
1044                 *eb = buf;
1045         } else {
1046                 free_extent_buffer(buf);
1047         }
1048         return 0;
1049 }
1050
1051 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
1052                                             u64 bytenr, u32 blocksize)
1053 {
1054         struct inode *btree_inode = root->fs_info->btree_inode;
1055         struct extent_buffer *eb;
1056         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
1057                                 bytenr, blocksize);
1058         return eb;
1059 }
1060
1061 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
1062                                                  u64 bytenr, u32 blocksize)
1063 {
1064         struct inode *btree_inode = root->fs_info->btree_inode;
1065         struct extent_buffer *eb;
1066
1067         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
1068                                  bytenr, blocksize, NULL);
1069         return eb;
1070 }
1071
1072
1073 int btrfs_write_tree_block(struct extent_buffer *buf)
1074 {
1075         return filemap_fdatawrite_range(buf->first_page->mapping, buf->start,
1076                                         buf->start + buf->len - 1);
1077 }
1078
1079 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
1080 {
1081         return filemap_fdatawait_range(buf->first_page->mapping,
1082                                        buf->start, buf->start + buf->len - 1);
1083 }
1084
1085 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
1086                                       u32 blocksize, u64 parent_transid)
1087 {
1088         struct extent_buffer *buf = NULL;
1089         int ret;
1090
1091         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1092         if (!buf)
1093                 return NULL;
1094
1095         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
1096
1097         if (ret == 0)
1098                 set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
1099         return buf;
1100
1101 }
1102
1103 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1104                      struct extent_buffer *buf)
1105 {
1106         struct inode *btree_inode = root->fs_info->btree_inode;
1107         if (btrfs_header_generation(buf) ==
1108             root->fs_info->running_transaction->transid) {
1109                 btrfs_assert_tree_locked(buf);
1110
1111                 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
1112                         spin_lock(&root->fs_info->delalloc_lock);
1113                         if (root->fs_info->dirty_metadata_bytes >= buf->len)
1114                                 root->fs_info->dirty_metadata_bytes -= buf->len;
1115                         else
1116                                 WARN_ON(1);
1117                         spin_unlock(&root->fs_info->delalloc_lock);
1118                 }
1119
1120                 /* ugh, clear_extent_buffer_dirty needs to lock the page */
1121                 btrfs_set_lock_blocking(buf);
1122                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
1123                                           buf);
1124         }
1125         return 0;
1126 }
1127
1128 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
1129                         u32 stripesize, struct btrfs_root *root,
1130                         struct btrfs_fs_info *fs_info,
1131                         u64 objectid)
1132 {
1133         root->node = NULL;
1134         root->commit_root = NULL;
1135         root->sectorsize = sectorsize;
1136         root->nodesize = nodesize;
1137         root->leafsize = leafsize;
1138         root->stripesize = stripesize;
1139         root->ref_cows = 0;
1140         root->track_dirty = 0;
1141         root->in_radix = 0;
1142         root->orphan_item_inserted = 0;
1143         root->orphan_cleanup_state = 0;
1144
1145         root->objectid = objectid;
1146         root->last_trans = 0;
1147         root->highest_objectid = 0;
1148         root->name = NULL;
1149         root->inode_tree = RB_ROOT;
1150         INIT_RADIX_TREE(&root->delayed_nodes_tree, GFP_ATOMIC);
1151         root->block_rsv = NULL;
1152         root->orphan_block_rsv = NULL;
1153
1154         INIT_LIST_HEAD(&root->dirty_list);
1155         INIT_LIST_HEAD(&root->orphan_list);
1156         INIT_LIST_HEAD(&root->root_list);
1157         spin_lock_init(&root->orphan_lock);
1158         spin_lock_init(&root->inode_lock);
1159         spin_lock_init(&root->accounting_lock);
1160         mutex_init(&root->objectid_mutex);
1161         mutex_init(&root->log_mutex);
1162         init_waitqueue_head(&root->log_writer_wait);
1163         init_waitqueue_head(&root->log_commit_wait[0]);
1164         init_waitqueue_head(&root->log_commit_wait[1]);
1165         atomic_set(&root->log_commit[0], 0);
1166         atomic_set(&root->log_commit[1], 0);
1167         atomic_set(&root->log_writers, 0);
1168         root->log_batch = 0;
1169         root->log_transid = 0;
1170         root->last_log_commit = 0;
1171         extent_io_tree_init(&root->dirty_log_pages,
1172                              fs_info->btree_inode->i_mapping);
1173
1174         memset(&root->root_key, 0, sizeof(root->root_key));
1175         memset(&root->root_item, 0, sizeof(root->root_item));
1176         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
1177         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
1178         root->defrag_trans_start = fs_info->generation;
1179         init_completion(&root->kobj_unregister);
1180         root->defrag_running = 0;
1181         root->root_key.objectid = objectid;
1182         root->anon_dev = 0;
1183         return 0;
1184 }
1185
1186 static int find_and_setup_root(struct btrfs_root *tree_root,
1187                                struct btrfs_fs_info *fs_info,
1188                                u64 objectid,
1189                                struct btrfs_root *root)
1190 {
1191         int ret;
1192         u32 blocksize;
1193         u64 generation;
1194
1195         __setup_root(tree_root->nodesize, tree_root->leafsize,
1196                      tree_root->sectorsize, tree_root->stripesize,
1197                      root, fs_info, objectid);
1198         ret = btrfs_find_last_root(tree_root, objectid,
1199                                    &root->root_item, &root->root_key);
1200         if (ret > 0)
1201                 return -ENOENT;
1202         BUG_ON(ret);
1203
1204         generation = btrfs_root_generation(&root->root_item);
1205         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1206         root->commit_root = NULL;
1207         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1208                                      blocksize, generation);
1209         if (!root->node || !btrfs_buffer_uptodate(root->node, generation)) {
1210                 free_extent_buffer(root->node);
1211                 root->node = NULL;
1212                 return -EIO;
1213         }
1214         root->commit_root = btrfs_root_node(root);
1215         return 0;
1216 }
1217
1218 static struct btrfs_root *btrfs_alloc_root(struct btrfs_fs_info *fs_info)
1219 {
1220         struct btrfs_root *root = kzalloc(sizeof(*root), GFP_NOFS);
1221         if (root)
1222                 root->fs_info = fs_info;
1223         return root;
1224 }
1225
1226 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1227                                          struct btrfs_fs_info *fs_info)
1228 {
1229         struct btrfs_root *root;
1230         struct btrfs_root *tree_root = fs_info->tree_root;
1231         struct extent_buffer *leaf;
1232
1233         root = btrfs_alloc_root(fs_info);
1234         if (!root)
1235                 return ERR_PTR(-ENOMEM);
1236
1237         __setup_root(tree_root->nodesize, tree_root->leafsize,
1238                      tree_root->sectorsize, tree_root->stripesize,
1239                      root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1240
1241         root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1242         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1243         root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1244         /*
1245          * log trees do not get reference counted because they go away
1246          * before a real commit is actually done.  They do store pointers
1247          * to file data extents, and those reference counts still get
1248          * updated (along with back refs to the log tree).
1249          */
1250         root->ref_cows = 0;
1251
1252         leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
1253                                       BTRFS_TREE_LOG_OBJECTID, NULL, 0, 0, 0);
1254         if (IS_ERR(leaf)) {
1255                 kfree(root);
1256                 return ERR_CAST(leaf);
1257         }
1258
1259         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1260         btrfs_set_header_bytenr(leaf, leaf->start);
1261         btrfs_set_header_generation(leaf, trans->transid);
1262         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1263         btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
1264         root->node = leaf;
1265
1266         write_extent_buffer(root->node, root->fs_info->fsid,
1267                             (unsigned long)btrfs_header_fsid(root->node),
1268                             BTRFS_FSID_SIZE);
1269         btrfs_mark_buffer_dirty(root->node);
1270         btrfs_tree_unlock(root->node);
1271         return root;
1272 }
1273
1274 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1275                              struct btrfs_fs_info *fs_info)
1276 {
1277         struct btrfs_root *log_root;
1278
1279         log_root = alloc_log_tree(trans, fs_info);
1280         if (IS_ERR(log_root))
1281                 return PTR_ERR(log_root);
1282         WARN_ON(fs_info->log_root_tree);
1283         fs_info->log_root_tree = log_root;
1284         return 0;
1285 }
1286
1287 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1288                        struct btrfs_root *root)
1289 {
1290         struct btrfs_root *log_root;
1291         struct btrfs_inode_item *inode_item;
1292
1293         log_root = alloc_log_tree(trans, root->fs_info);
1294         if (IS_ERR(log_root))
1295                 return PTR_ERR(log_root);
1296
1297         log_root->last_trans = trans->transid;
1298         log_root->root_key.offset = root->root_key.objectid;
1299
1300         inode_item = &log_root->root_item.inode;
1301         inode_item->generation = cpu_to_le64(1);
1302         inode_item->size = cpu_to_le64(3);
1303         inode_item->nlink = cpu_to_le32(1);
1304         inode_item->nbytes = cpu_to_le64(root->leafsize);
1305         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
1306
1307         btrfs_set_root_node(&log_root->root_item, log_root->node);
1308
1309         WARN_ON(root->log_root);
1310         root->log_root = log_root;
1311         root->log_transid = 0;
1312         root->last_log_commit = 0;
1313         return 0;
1314 }
1315
1316 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
1317                                                struct btrfs_key *location)
1318 {
1319         struct btrfs_root *root;
1320         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1321         struct btrfs_path *path;
1322         struct extent_buffer *l;
1323         u64 generation;
1324         u32 blocksize;
1325         int ret = 0;
1326
1327         root = btrfs_alloc_root(fs_info);
1328         if (!root)
1329                 return ERR_PTR(-ENOMEM);
1330         if (location->offset == (u64)-1) {
1331                 ret = find_and_setup_root(tree_root, fs_info,
1332                                           location->objectid, root);
1333                 if (ret) {
1334                         kfree(root);
1335                         return ERR_PTR(ret);
1336                 }
1337                 goto out;
1338         }
1339
1340         __setup_root(tree_root->nodesize, tree_root->leafsize,
1341                      tree_root->sectorsize, tree_root->stripesize,
1342                      root, fs_info, location->objectid);
1343
1344         path = btrfs_alloc_path();
1345         if (!path) {
1346                 kfree(root);
1347                 return ERR_PTR(-ENOMEM);
1348         }
1349         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
1350         if (ret == 0) {
1351                 l = path->nodes[0];
1352                 read_extent_buffer(l, &root->root_item,
1353                                 btrfs_item_ptr_offset(l, path->slots[0]),
1354                                 sizeof(root->root_item));
1355                 memcpy(&root->root_key, location, sizeof(*location));
1356         }
1357         btrfs_free_path(path);
1358         if (ret) {
1359                 kfree(root);
1360                 if (ret > 0)
1361                         ret = -ENOENT;
1362                 return ERR_PTR(ret);
1363         }
1364
1365         generation = btrfs_root_generation(&root->root_item);
1366         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1367         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1368                                      blocksize, generation);
1369         root->commit_root = btrfs_root_node(root);
1370         BUG_ON(!root->node);
1371 out:
1372         if (location->objectid != BTRFS_TREE_LOG_OBJECTID) {
1373                 root->ref_cows = 1;
1374                 btrfs_check_and_init_root_item(&root->root_item);
1375         }
1376
1377         return root;
1378 }
1379
1380 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
1381                                               struct btrfs_key *location)
1382 {
1383         struct btrfs_root *root;
1384         int ret;
1385
1386         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1387                 return fs_info->tree_root;
1388         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1389                 return fs_info->extent_root;
1390         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1391                 return fs_info->chunk_root;
1392         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1393                 return fs_info->dev_root;
1394         if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
1395                 return fs_info->csum_root;
1396 again:
1397         spin_lock(&fs_info->fs_roots_radix_lock);
1398         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1399                                  (unsigned long)location->objectid);
1400         spin_unlock(&fs_info->fs_roots_radix_lock);
1401         if (root)
1402                 return root;
1403
1404         root = btrfs_read_fs_root_no_radix(fs_info->tree_root, location);
1405         if (IS_ERR(root))
1406                 return root;
1407
1408         root->free_ino_ctl = kzalloc(sizeof(*root->free_ino_ctl), GFP_NOFS);
1409         root->free_ino_pinned = kzalloc(sizeof(*root->free_ino_pinned),
1410                                         GFP_NOFS);
1411         if (!root->free_ino_pinned || !root->free_ino_ctl) {
1412                 ret = -ENOMEM;
1413                 goto fail;
1414         }
1415
1416         btrfs_init_free_ino_ctl(root);
1417         mutex_init(&root->fs_commit_mutex);
1418         spin_lock_init(&root->cache_lock);
1419         init_waitqueue_head(&root->cache_wait);
1420
1421         ret = get_anon_bdev(&root->anon_dev);
1422         if (ret)
1423                 goto fail;
1424
1425         if (btrfs_root_refs(&root->root_item) == 0) {
1426                 ret = -ENOENT;
1427                 goto fail;
1428         }
1429
1430         ret = btrfs_find_orphan_item(fs_info->tree_root, location->objectid);
1431         if (ret < 0)
1432                 goto fail;
1433         if (ret == 0)
1434                 root->orphan_item_inserted = 1;
1435
1436         ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
1437         if (ret)
1438                 goto fail;
1439
1440         spin_lock(&fs_info->fs_roots_radix_lock);
1441         ret = radix_tree_insert(&fs_info->fs_roots_radix,
1442                                 (unsigned long)root->root_key.objectid,
1443                                 root);
1444         if (ret == 0)
1445                 root->in_radix = 1;
1446
1447         spin_unlock(&fs_info->fs_roots_radix_lock);
1448         radix_tree_preload_end();
1449         if (ret) {
1450                 if (ret == -EEXIST) {
1451                         free_fs_root(root);
1452                         goto again;
1453                 }
1454                 goto fail;
1455         }
1456
1457         ret = btrfs_find_dead_roots(fs_info->tree_root,
1458                                     root->root_key.objectid);
1459         WARN_ON(ret);
1460         return root;
1461 fail:
1462         free_fs_root(root);
1463         return ERR_PTR(ret);
1464 }
1465
1466 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1467 {
1468         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1469         int ret = 0;
1470         struct btrfs_device *device;
1471         struct backing_dev_info *bdi;
1472
1473         rcu_read_lock();
1474         list_for_each_entry_rcu(device, &info->fs_devices->devices, dev_list) {
1475                 if (!device->bdev)
1476                         continue;
1477                 bdi = blk_get_backing_dev_info(device->bdev);
1478                 if (bdi && bdi_congested(bdi, bdi_bits)) {
1479                         ret = 1;
1480                         break;
1481                 }
1482         }
1483         rcu_read_unlock();
1484         return ret;
1485 }
1486
1487 /*
1488  * If this fails, caller must call bdi_destroy() to get rid of the
1489  * bdi again.
1490  */
1491 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1492 {
1493         int err;
1494
1495         bdi->capabilities = BDI_CAP_MAP_COPY;
1496         err = bdi_setup_and_register(bdi, "btrfs", BDI_CAP_MAP_COPY);
1497         if (err)
1498                 return err;
1499
1500         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1501         bdi->congested_fn       = btrfs_congested_fn;
1502         bdi->congested_data     = info;
1503         return 0;
1504 }
1505
1506 static int bio_ready_for_csum(struct bio *bio)
1507 {
1508         u64 length = 0;
1509         u64 buf_len = 0;
1510         u64 start = 0;
1511         struct page *page;
1512         struct extent_io_tree *io_tree = NULL;
1513         struct bio_vec *bvec;
1514         int i;
1515         int ret;
1516
1517         bio_for_each_segment(bvec, bio, i) {
1518                 page = bvec->bv_page;
1519                 if (page->private == EXTENT_PAGE_PRIVATE) {
1520                         length += bvec->bv_len;
1521                         continue;
1522                 }
1523                 if (!page->private) {
1524                         length += bvec->bv_len;
1525                         continue;
1526                 }
1527                 length = bvec->bv_len;
1528                 buf_len = page->private >> 2;
1529                 start = page_offset(page) + bvec->bv_offset;
1530                 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1531         }
1532         /* are we fully contained in this bio? */
1533         if (buf_len <= length)
1534                 return 1;
1535
1536         ret = extent_range_uptodate(io_tree, start + length,
1537                                     start + buf_len - 1);
1538         return ret;
1539 }
1540
1541 /*
1542  * called by the kthread helper functions to finally call the bio end_io
1543  * functions.  This is where read checksum verification actually happens
1544  */
1545 static void end_workqueue_fn(struct btrfs_work *work)
1546 {
1547         struct bio *bio;
1548         struct end_io_wq *end_io_wq;
1549         struct btrfs_fs_info *fs_info;
1550         int error;
1551
1552         end_io_wq = container_of(work, struct end_io_wq, work);
1553         bio = end_io_wq->bio;
1554         fs_info = end_io_wq->info;
1555
1556         /* metadata bio reads are special because the whole tree block must
1557          * be checksummed at once.  This makes sure the entire block is in
1558          * ram and up to date before trying to verify things.  For
1559          * blocksize <= pagesize, it is basically a noop
1560          */
1561         if (!(bio->bi_rw & REQ_WRITE) && end_io_wq->metadata &&
1562             !bio_ready_for_csum(bio)) {
1563                 btrfs_queue_worker(&fs_info->endio_meta_workers,
1564                                    &end_io_wq->work);
1565                 return;
1566         }
1567         error = end_io_wq->error;
1568         bio->bi_private = end_io_wq->private;
1569         bio->bi_end_io = end_io_wq->end_io;
1570         kfree(end_io_wq);
1571         bio_endio(bio, error);
1572 }
1573
1574 static int cleaner_kthread(void *arg)
1575 {
1576         struct btrfs_root *root = arg;
1577
1578         do {
1579                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1580
1581                 if (!(root->fs_info->sb->s_flags & MS_RDONLY) &&
1582                     mutex_trylock(&root->fs_info->cleaner_mutex)) {
1583                         btrfs_run_delayed_iputs(root);
1584                         btrfs_clean_old_snapshots(root);
1585                         mutex_unlock(&root->fs_info->cleaner_mutex);
1586                         btrfs_run_defrag_inodes(root->fs_info);
1587                 }
1588
1589                 if (!try_to_freeze()) {
1590                         set_current_state(TASK_INTERRUPTIBLE);
1591                         if (!kthread_should_stop())
1592                                 schedule();
1593                         __set_current_state(TASK_RUNNING);
1594                 }
1595         } while (!kthread_should_stop());
1596         return 0;
1597 }
1598
1599 static int transaction_kthread(void *arg)
1600 {
1601         struct btrfs_root *root = arg;
1602         struct btrfs_trans_handle *trans;
1603         struct btrfs_transaction *cur;
1604         u64 transid;
1605         unsigned long now;
1606         unsigned long delay;
1607         int ret;
1608
1609         do {
1610                 delay = HZ * 30;
1611                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1612                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1613
1614                 spin_lock(&root->fs_info->trans_lock);
1615                 cur = root->fs_info->running_transaction;
1616                 if (!cur) {
1617                         spin_unlock(&root->fs_info->trans_lock);
1618                         goto sleep;
1619                 }
1620
1621                 now = get_seconds();
1622                 if (!cur->blocked &&
1623                     (now < cur->start_time || now - cur->start_time < 30)) {
1624                         spin_unlock(&root->fs_info->trans_lock);
1625                         delay = HZ * 5;
1626                         goto sleep;
1627                 }
1628                 transid = cur->transid;
1629                 spin_unlock(&root->fs_info->trans_lock);
1630
1631                 trans = btrfs_join_transaction(root);
1632                 BUG_ON(IS_ERR(trans));
1633                 if (transid == trans->transid) {
1634                         ret = btrfs_commit_transaction(trans, root);
1635                         BUG_ON(ret);
1636                 } else {
1637                         btrfs_end_transaction(trans, root);
1638                 }
1639 sleep:
1640                 wake_up_process(root->fs_info->cleaner_kthread);
1641                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1642
1643                 if (!try_to_freeze()) {
1644                         set_current_state(TASK_INTERRUPTIBLE);
1645                         if (!kthread_should_stop() &&
1646                             !btrfs_transaction_blocked(root->fs_info))
1647                                 schedule_timeout(delay);
1648                         __set_current_state(TASK_RUNNING);
1649                 }
1650         } while (!kthread_should_stop());
1651         return 0;
1652 }
1653
1654 /*
1655  * this will find the highest generation in the array of
1656  * root backups.  The index of the highest array is returned,
1657  * or -1 if we can't find anything.
1658  *
1659  * We check to make sure the array is valid by comparing the
1660  * generation of the latest  root in the array with the generation
1661  * in the super block.  If they don't match we pitch it.
1662  */
1663 static int find_newest_super_backup(struct btrfs_fs_info *info, u64 newest_gen)
1664 {
1665         u64 cur;
1666         int newest_index = -1;
1667         struct btrfs_root_backup *root_backup;
1668         int i;
1669
1670         for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; i++) {
1671                 root_backup = info->super_copy->super_roots + i;
1672                 cur = btrfs_backup_tree_root_gen(root_backup);
1673                 if (cur == newest_gen)
1674                         newest_index = i;
1675         }
1676
1677         /* check to see if we actually wrapped around */
1678         if (newest_index == BTRFS_NUM_BACKUP_ROOTS - 1) {
1679                 root_backup = info->super_copy->super_roots;
1680                 cur = btrfs_backup_tree_root_gen(root_backup);
1681                 if (cur == newest_gen)
1682                         newest_index = 0;
1683         }
1684         return newest_index;
1685 }
1686
1687
1688 /*
1689  * find the oldest backup so we know where to store new entries
1690  * in the backup array.  This will set the backup_root_index
1691  * field in the fs_info struct
1692  */
1693 static void find_oldest_super_backup(struct btrfs_fs_info *info,
1694                                      u64 newest_gen)
1695 {
1696         int newest_index = -1;
1697
1698         newest_index = find_newest_super_backup(info, newest_gen);
1699         /* if there was garbage in there, just move along */
1700         if (newest_index == -1) {
1701                 info->backup_root_index = 0;
1702         } else {
1703                 info->backup_root_index = (newest_index + 1) % BTRFS_NUM_BACKUP_ROOTS;
1704         }
1705 }
1706
1707 /*
1708  * copy all the root pointers into the super backup array.
1709  * this will bump the backup pointer by one when it is
1710  * done
1711  */
1712 static void backup_super_roots(struct btrfs_fs_info *info)
1713 {
1714         int next_backup;
1715         struct btrfs_root_backup *root_backup;
1716         int last_backup;
1717
1718         next_backup = info->backup_root_index;
1719         last_backup = (next_backup + BTRFS_NUM_BACKUP_ROOTS - 1) %
1720                 BTRFS_NUM_BACKUP_ROOTS;
1721
1722         /*
1723          * just overwrite the last backup if we're at the same generation
1724          * this happens only at umount
1725          */
1726         root_backup = info->super_for_commit->super_roots + last_backup;
1727         if (btrfs_backup_tree_root_gen(root_backup) ==
1728             btrfs_header_generation(info->tree_root->node))
1729                 next_backup = last_backup;
1730
1731         root_backup = info->super_for_commit->super_roots + next_backup;
1732
1733         /*
1734          * make sure all of our padding and empty slots get zero filled
1735          * regardless of which ones we use today
1736          */
1737         memset(root_backup, 0, sizeof(*root_backup));
1738
1739         info->backup_root_index = (next_backup + 1) % BTRFS_NUM_BACKUP_ROOTS;
1740
1741         btrfs_set_backup_tree_root(root_backup, info->tree_root->node->start);
1742         btrfs_set_backup_tree_root_gen(root_backup,
1743                                btrfs_header_generation(info->tree_root->node));
1744
1745         btrfs_set_backup_tree_root_level(root_backup,
1746                                btrfs_header_level(info->tree_root->node));
1747
1748         btrfs_set_backup_chunk_root(root_backup, info->chunk_root->node->start);
1749         btrfs_set_backup_chunk_root_gen(root_backup,
1750                                btrfs_header_generation(info->chunk_root->node));
1751         btrfs_set_backup_chunk_root_level(root_backup,
1752                                btrfs_header_level(info->chunk_root->node));
1753
1754         btrfs_set_backup_extent_root(root_backup, info->extent_root->node->start);
1755         btrfs_set_backup_extent_root_gen(root_backup,
1756                                btrfs_header_generation(info->extent_root->node));
1757         btrfs_set_backup_extent_root_level(root_backup,
1758                                btrfs_header_level(info->extent_root->node));
1759
1760         /*
1761          * we might commit during log recovery, which happens before we set
1762          * the fs_root.  Make sure it is valid before we fill it in.
1763          */
1764         if (info->fs_root && info->fs_root->node) {
1765                 btrfs_set_backup_fs_root(root_backup,
1766                                          info->fs_root->node->start);
1767                 btrfs_set_backup_fs_root_gen(root_backup,
1768                                btrfs_header_generation(info->fs_root->node));
1769                 btrfs_set_backup_fs_root_level(root_backup,
1770                                btrfs_header_level(info->fs_root->node));
1771         }
1772
1773         btrfs_set_backup_dev_root(root_backup, info->dev_root->node->start);
1774         btrfs_set_backup_dev_root_gen(root_backup,
1775                                btrfs_header_generation(info->dev_root->node));
1776         btrfs_set_backup_dev_root_level(root_backup,
1777                                        btrfs_header_level(info->dev_root->node));
1778
1779         btrfs_set_backup_csum_root(root_backup, info->csum_root->node->start);
1780         btrfs_set_backup_csum_root_gen(root_backup,
1781                                btrfs_header_generation(info->csum_root->node));
1782         btrfs_set_backup_csum_root_level(root_backup,
1783                                btrfs_header_level(info->csum_root->node));
1784
1785         btrfs_set_backup_total_bytes(root_backup,
1786                              btrfs_super_total_bytes(info->super_copy));
1787         btrfs_set_backup_bytes_used(root_backup,
1788                              btrfs_super_bytes_used(info->super_copy));
1789         btrfs_set_backup_num_devices(root_backup,
1790                              btrfs_super_num_devices(info->super_copy));
1791
1792         /*
1793          * if we don't copy this out to the super_copy, it won't get remembered
1794          * for the next commit
1795          */
1796         memcpy(&info->super_copy->super_roots,
1797                &info->super_for_commit->super_roots,
1798                sizeof(*root_backup) * BTRFS_NUM_BACKUP_ROOTS);
1799 }
1800
1801 /*
1802  * this copies info out of the root backup array and back into
1803  * the in-memory super block.  It is meant to help iterate through
1804  * the array, so you send it the number of backups you've already
1805  * tried and the last backup index you used.
1806  *
1807  * this returns -1 when it has tried all the backups
1808  */
1809 static noinline int next_root_backup(struct btrfs_fs_info *info,
1810                                      struct btrfs_super_block *super,
1811                                      int *num_backups_tried, int *backup_index)
1812 {
1813         struct btrfs_root_backup *root_backup;
1814         int newest = *backup_index;
1815
1816         if (*num_backups_tried == 0) {
1817                 u64 gen = btrfs_super_generation(super);
1818
1819                 newest = find_newest_super_backup(info, gen);
1820                 if (newest == -1)
1821                         return -1;
1822
1823                 *backup_index = newest;
1824                 *num_backups_tried = 1;
1825         } else if (*num_backups_tried == BTRFS_NUM_BACKUP_ROOTS) {
1826                 /* we've tried all the backups, all done */
1827                 return -1;
1828         } else {
1829                 /* jump to the next oldest backup */
1830                 newest = (*backup_index + BTRFS_NUM_BACKUP_ROOTS - 1) %
1831                         BTRFS_NUM_BACKUP_ROOTS;
1832                 *backup_index = newest;
1833                 *num_backups_tried += 1;
1834         }
1835         root_backup = super->super_roots + newest;
1836
1837         btrfs_set_super_generation(super,
1838                                    btrfs_backup_tree_root_gen(root_backup));
1839         btrfs_set_super_root(super, btrfs_backup_tree_root(root_backup));
1840         btrfs_set_super_root_level(super,
1841                                    btrfs_backup_tree_root_level(root_backup));
1842         btrfs_set_super_bytes_used(super, btrfs_backup_bytes_used(root_backup));
1843
1844         /*
1845          * fixme: the total bytes and num_devices need to match or we should
1846          * need a fsck
1847          */
1848         btrfs_set_super_total_bytes(super, btrfs_backup_total_bytes(root_backup));
1849         btrfs_set_super_num_devices(super, btrfs_backup_num_devices(root_backup));
1850         return 0;
1851 }
1852
1853 /* helper to cleanup tree roots */
1854 static void free_root_pointers(struct btrfs_fs_info *info, int chunk_root)
1855 {
1856         free_extent_buffer(info->tree_root->node);
1857         free_extent_buffer(info->tree_root->commit_root);
1858         free_extent_buffer(info->dev_root->node);
1859         free_extent_buffer(info->dev_root->commit_root);
1860         free_extent_buffer(info->extent_root->node);
1861         free_extent_buffer(info->extent_root->commit_root);
1862         free_extent_buffer(info->csum_root->node);
1863         free_extent_buffer(info->csum_root->commit_root);
1864
1865         info->tree_root->node = NULL;
1866         info->tree_root->commit_root = NULL;
1867         info->dev_root->node = NULL;
1868         info->dev_root->commit_root = NULL;
1869         info->extent_root->node = NULL;
1870         info->extent_root->commit_root = NULL;
1871         info->csum_root->node = NULL;
1872         info->csum_root->commit_root = NULL;
1873
1874         if (chunk_root) {
1875                 free_extent_buffer(info->chunk_root->node);
1876                 free_extent_buffer(info->chunk_root->commit_root);
1877                 info->chunk_root->node = NULL;
1878                 info->chunk_root->commit_root = NULL;
1879         }
1880 }
1881
1882
1883 int open_ctree(struct super_block *sb,
1884                struct btrfs_fs_devices *fs_devices,
1885                char *options)
1886 {
1887         u32 sectorsize;
1888         u32 nodesize;
1889         u32 leafsize;
1890         u32 blocksize;
1891         u32 stripesize;
1892         u64 generation;
1893         u64 features;
1894         struct btrfs_key location;
1895         struct buffer_head *bh;
1896         struct btrfs_super_block *disk_super;
1897         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
1898         struct btrfs_root *tree_root;
1899         struct btrfs_root *extent_root;
1900         struct btrfs_root *csum_root;
1901         struct btrfs_root *chunk_root;
1902         struct btrfs_root *dev_root;
1903         struct btrfs_root *log_tree_root;
1904         int ret;
1905         int err = -EINVAL;
1906         int num_backups_tried = 0;
1907         int backup_index = 0;
1908
1909         tree_root = fs_info->tree_root = btrfs_alloc_root(fs_info);
1910         extent_root = fs_info->extent_root = btrfs_alloc_root(fs_info);
1911         csum_root = fs_info->csum_root = btrfs_alloc_root(fs_info);
1912         chunk_root = fs_info->chunk_root = btrfs_alloc_root(fs_info);
1913         dev_root = fs_info->dev_root = btrfs_alloc_root(fs_info);
1914
1915         if (!tree_root || !extent_root || !csum_root ||
1916             !chunk_root || !dev_root) {
1917                 err = -ENOMEM;
1918                 goto fail;
1919         }
1920
1921         ret = init_srcu_struct(&fs_info->subvol_srcu);
1922         if (ret) {
1923                 err = ret;
1924                 goto fail;
1925         }
1926
1927         ret = setup_bdi(fs_info, &fs_info->bdi);
1928         if (ret) {
1929                 err = ret;
1930                 goto fail_srcu;
1931         }
1932
1933         fs_info->btree_inode = new_inode(sb);
1934         if (!fs_info->btree_inode) {
1935                 err = -ENOMEM;
1936                 goto fail_bdi;
1937         }
1938
1939         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
1940
1941         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
1942         INIT_LIST_HEAD(&fs_info->trans_list);
1943         INIT_LIST_HEAD(&fs_info->dead_roots);
1944         INIT_LIST_HEAD(&fs_info->delayed_iputs);
1945         INIT_LIST_HEAD(&fs_info->hashers);
1946         INIT_LIST_HEAD(&fs_info->delalloc_inodes);
1947         INIT_LIST_HEAD(&fs_info->ordered_operations);
1948         INIT_LIST_HEAD(&fs_info->caching_block_groups);
1949         spin_lock_init(&fs_info->delalloc_lock);
1950         spin_lock_init(&fs_info->trans_lock);
1951         spin_lock_init(&fs_info->ref_cache_lock);
1952         spin_lock_init(&fs_info->fs_roots_radix_lock);
1953         spin_lock_init(&fs_info->delayed_iput_lock);
1954         spin_lock_init(&fs_info->defrag_inodes_lock);
1955         spin_lock_init(&fs_info->free_chunk_lock);
1956         mutex_init(&fs_info->reloc_mutex);
1957
1958         init_completion(&fs_info->kobj_unregister);
1959         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1960         INIT_LIST_HEAD(&fs_info->space_info);
1961         btrfs_mapping_init(&fs_info->mapping_tree);
1962         btrfs_init_block_rsv(&fs_info->global_block_rsv);
1963         btrfs_init_block_rsv(&fs_info->delalloc_block_rsv);
1964         btrfs_init_block_rsv(&fs_info->trans_block_rsv);
1965         btrfs_init_block_rsv(&fs_info->chunk_block_rsv);
1966         btrfs_init_block_rsv(&fs_info->empty_block_rsv);
1967         btrfs_init_block_rsv(&fs_info->delayed_block_rsv);
1968         atomic_set(&fs_info->nr_async_submits, 0);
1969         atomic_set(&fs_info->async_delalloc_pages, 0);
1970         atomic_set(&fs_info->async_submit_draining, 0);
1971         atomic_set(&fs_info->nr_async_bios, 0);
1972         atomic_set(&fs_info->defrag_running, 0);
1973         fs_info->sb = sb;
1974         fs_info->max_inline = 8192 * 1024;
1975         fs_info->metadata_ratio = 0;
1976         fs_info->defrag_inodes = RB_ROOT;
1977         fs_info->trans_no_join = 0;
1978         fs_info->free_chunk_space = 0;
1979
1980         /* readahead state */
1981         INIT_RADIX_TREE(&fs_info->reada_tree, GFP_NOFS & ~__GFP_WAIT);
1982         spin_lock_init(&fs_info->reada_lock);
1983
1984         fs_info->thread_pool_size = min_t(unsigned long,
1985                                           num_online_cpus() + 2, 8);
1986
1987         INIT_LIST_HEAD(&fs_info->ordered_extents);
1988         spin_lock_init(&fs_info->ordered_extent_lock);
1989         fs_info->delayed_root = kmalloc(sizeof(struct btrfs_delayed_root),
1990                                         GFP_NOFS);
1991         if (!fs_info->delayed_root) {
1992                 err = -ENOMEM;
1993                 goto fail_iput;
1994         }
1995         btrfs_init_delayed_root(fs_info->delayed_root);
1996
1997         mutex_init(&fs_info->scrub_lock);
1998         atomic_set(&fs_info->scrubs_running, 0);
1999         atomic_set(&fs_info->scrub_pause_req, 0);
2000         atomic_set(&fs_info->scrubs_paused, 0);
2001         atomic_set(&fs_info->scrub_cancel_req, 0);
2002         init_waitqueue_head(&fs_info->scrub_pause_wait);
2003         init_rwsem(&fs_info->scrub_super_lock);
2004         fs_info->scrub_workers_refcnt = 0;
2005
2006         sb->s_blocksize = 4096;
2007         sb->s_blocksize_bits = blksize_bits(4096);
2008         sb->s_bdi = &fs_info->bdi;
2009
2010         fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
2011         set_nlink(fs_info->btree_inode, 1);
2012         /*
2013          * we set the i_size on the btree inode to the max possible int.
2014          * the real end of the address space is determined by all of
2015          * the devices in the system
2016          */
2017         fs_info->btree_inode->i_size = OFFSET_MAX;
2018         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
2019         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
2020
2021         RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
2022         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
2023                              fs_info->btree_inode->i_mapping);
2024         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree);
2025
2026         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
2027
2028         BTRFS_I(fs_info->btree_inode)->root = tree_root;
2029         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
2030                sizeof(struct btrfs_key));
2031         BTRFS_I(fs_info->btree_inode)->dummy_inode = 1;
2032         insert_inode_hash(fs_info->btree_inode);
2033
2034         spin_lock_init(&fs_info->block_group_cache_lock);
2035         fs_info->block_group_cache_tree = RB_ROOT;
2036
2037         extent_io_tree_init(&fs_info->freed_extents[0],
2038                              fs_info->btree_inode->i_mapping);
2039         extent_io_tree_init(&fs_info->freed_extents[1],
2040                              fs_info->btree_inode->i_mapping);
2041         fs_info->pinned_extents = &fs_info->freed_extents[0];
2042         fs_info->do_barriers = 1;
2043
2044
2045         mutex_init(&fs_info->ordered_operations_mutex);
2046         mutex_init(&fs_info->tree_log_mutex);
2047         mutex_init(&fs_info->chunk_mutex);
2048         mutex_init(&fs_info->transaction_kthread_mutex);
2049         mutex_init(&fs_info->cleaner_mutex);
2050         mutex_init(&fs_info->volume_mutex);
2051         init_rwsem(&fs_info->extent_commit_sem);
2052         init_rwsem(&fs_info->cleanup_work_sem);
2053         init_rwsem(&fs_info->subvol_sem);
2054
2055         btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
2056         btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
2057
2058         init_waitqueue_head(&fs_info->transaction_throttle);
2059         init_waitqueue_head(&fs_info->transaction_wait);
2060         init_waitqueue_head(&fs_info->transaction_blocked_wait);
2061         init_waitqueue_head(&fs_info->async_submit_wait);
2062
2063         __setup_root(4096, 4096, 4096, 4096, tree_root,
2064                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
2065
2066         bh = btrfs_read_dev_super(fs_devices->latest_bdev);
2067         if (!bh) {
2068                 err = -EINVAL;
2069                 goto fail_alloc;
2070         }
2071
2072         memcpy(fs_info->super_copy, bh->b_data, sizeof(*fs_info->super_copy));
2073         memcpy(fs_info->super_for_commit, fs_info->super_copy,
2074                sizeof(*fs_info->super_for_commit));
2075         brelse(bh);
2076
2077         memcpy(fs_info->fsid, fs_info->super_copy->fsid, BTRFS_FSID_SIZE);
2078
2079         disk_super = fs_info->super_copy;
2080         if (!btrfs_super_root(disk_super))
2081                 goto fail_alloc;
2082
2083         /* check FS state, whether FS is broken. */
2084         fs_info->fs_state |= btrfs_super_flags(disk_super);
2085
2086         btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY);
2087
2088         /*
2089          * run through our array of backup supers and setup
2090          * our ring pointer to the oldest one
2091          */
2092         generation = btrfs_super_generation(disk_super);
2093         find_oldest_super_backup(fs_info, generation);
2094
2095         /*
2096          * In the long term, we'll store the compression type in the super
2097          * block, and it'll be used for per file compression control.
2098          */
2099         fs_info->compress_type = BTRFS_COMPRESS_ZLIB;
2100
2101         ret = btrfs_parse_options(tree_root, options);
2102         if (ret) {
2103                 err = ret;
2104                 goto fail_alloc;
2105         }
2106
2107         features = btrfs_super_incompat_flags(disk_super) &
2108                 ~BTRFS_FEATURE_INCOMPAT_SUPP;
2109         if (features) {
2110                 printk(KERN_ERR "BTRFS: couldn't mount because of "
2111                        "unsupported optional features (%Lx).\n",
2112                        (unsigned long long)features);
2113                 err = -EINVAL;
2114                 goto fail_alloc;
2115         }
2116
2117         features = btrfs_super_incompat_flags(disk_super);
2118         features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
2119         if (tree_root->fs_info->compress_type & BTRFS_COMPRESS_LZO)
2120                 features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
2121         btrfs_set_super_incompat_flags(disk_super, features);
2122
2123         features = btrfs_super_compat_ro_flags(disk_super) &
2124                 ~BTRFS_FEATURE_COMPAT_RO_SUPP;
2125         if (!(sb->s_flags & MS_RDONLY) && features) {
2126                 printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
2127                        "unsupported option features (%Lx).\n",
2128                        (unsigned long long)features);
2129                 err = -EINVAL;
2130                 goto fail_alloc;
2131         }
2132
2133         btrfs_init_workers(&fs_info->generic_worker,
2134                            "genwork", 1, NULL);
2135
2136         btrfs_init_workers(&fs_info->workers, "worker",
2137                            fs_info->thread_pool_size,
2138                            &fs_info->generic_worker);
2139
2140         btrfs_init_workers(&fs_info->delalloc_workers, "delalloc",
2141                            fs_info->thread_pool_size,
2142                            &fs_info->generic_worker);
2143
2144         btrfs_init_workers(&fs_info->submit_workers, "submit",
2145                            min_t(u64, fs_devices->num_devices,
2146                            fs_info->thread_pool_size),
2147                            &fs_info->generic_worker);
2148
2149         btrfs_init_workers(&fs_info->caching_workers, "cache",
2150                            2, &fs_info->generic_worker);
2151
2152         /* a higher idle thresh on the submit workers makes it much more
2153          * likely that bios will be send down in a sane order to the
2154          * devices
2155          */
2156         fs_info->submit_workers.idle_thresh = 64;
2157
2158         fs_info->workers.idle_thresh = 16;
2159         fs_info->workers.ordered = 1;
2160
2161         fs_info->delalloc_workers.idle_thresh = 2;
2162         fs_info->delalloc_workers.ordered = 1;
2163
2164         btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1,
2165                            &fs_info->generic_worker);
2166         btrfs_init_workers(&fs_info->endio_workers, "endio",
2167                            fs_info->thread_pool_size,
2168                            &fs_info->generic_worker);
2169         btrfs_init_workers(&fs_info->endio_meta_workers, "endio-meta",
2170                            fs_info->thread_pool_size,
2171                            &fs_info->generic_worker);
2172         btrfs_init_workers(&fs_info->endio_meta_write_workers,
2173                            "endio-meta-write", fs_info->thread_pool_size,
2174                            &fs_info->generic_worker);
2175         btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
2176                            fs_info->thread_pool_size,
2177                            &fs_info->generic_worker);
2178         btrfs_init_workers(&fs_info->endio_freespace_worker, "freespace-write",
2179                            1, &fs_info->generic_worker);
2180         btrfs_init_workers(&fs_info->delayed_workers, "delayed-meta",
2181                            fs_info->thread_pool_size,
2182                            &fs_info->generic_worker);
2183         btrfs_init_workers(&fs_info->readahead_workers, "readahead",
2184                            fs_info->thread_pool_size,
2185                            &fs_info->generic_worker);
2186
2187         /*
2188          * endios are largely parallel and should have a very
2189          * low idle thresh
2190          */
2191         fs_info->endio_workers.idle_thresh = 4;
2192         fs_info->endio_meta_workers.idle_thresh = 4;
2193
2194         fs_info->endio_write_workers.idle_thresh = 2;
2195         fs_info->endio_meta_write_workers.idle_thresh = 2;
2196         fs_info->readahead_workers.idle_thresh = 2;
2197
2198         /*
2199          * btrfs_start_workers can really only fail because of ENOMEM so just
2200          * return -ENOMEM if any of these fail.
2201          */
2202         ret = btrfs_start_workers(&fs_info->workers);
2203         ret |= btrfs_start_workers(&fs_info->generic_worker);
2204         ret |= btrfs_start_workers(&fs_info->submit_workers);
2205         ret |= btrfs_start_workers(&fs_info->delalloc_workers);
2206         ret |= btrfs_start_workers(&fs_info->fixup_workers);
2207         ret |= btrfs_start_workers(&fs_info->endio_workers);
2208         ret |= btrfs_start_workers(&fs_info->endio_meta_workers);
2209         ret |= btrfs_start_workers(&fs_info->endio_meta_write_workers);
2210         ret |= btrfs_start_workers(&fs_info->endio_write_workers);
2211         ret |= btrfs_start_workers(&fs_info->endio_freespace_worker);
2212         ret |= btrfs_start_workers(&fs_info->delayed_workers);
2213         ret |= btrfs_start_workers(&fs_info->caching_workers);
2214         ret |= btrfs_start_workers(&fs_info->readahead_workers);
2215         if (ret) {
2216                 ret = -ENOMEM;
2217                 goto fail_sb_buffer;
2218         }
2219
2220         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
2221         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
2222                                     4 * 1024 * 1024 / PAGE_CACHE_SIZE);
2223
2224         nodesize = btrfs_super_nodesize(disk_super);
2225         leafsize = btrfs_super_leafsize(disk_super);
2226         sectorsize = btrfs_super_sectorsize(disk_super);
2227         stripesize = btrfs_super_stripesize(disk_super);
2228         tree_root->nodesize = nodesize;
2229         tree_root->leafsize = leafsize;
2230         tree_root->sectorsize = sectorsize;
2231         tree_root->stripesize = stripesize;
2232
2233         sb->s_blocksize = sectorsize;
2234         sb->s_blocksize_bits = blksize_bits(sectorsize);
2235
2236         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
2237                     sizeof(disk_super->magic))) {
2238                 printk(KERN_INFO "btrfs: valid FS not found on %s\n", sb->s_id);
2239                 goto fail_sb_buffer;
2240         }
2241
2242         mutex_lock(&fs_info->chunk_mutex);
2243         ret = btrfs_read_sys_array(tree_root);
2244         mutex_unlock(&fs_info->chunk_mutex);
2245         if (ret) {
2246                 printk(KERN_WARNING "btrfs: failed to read the system "
2247                        "array on %s\n", sb->s_id);
2248                 goto fail_sb_buffer;
2249         }
2250
2251         blocksize = btrfs_level_size(tree_root,
2252                                      btrfs_super_chunk_root_level(disk_super));
2253         generation = btrfs_super_chunk_root_generation(disk_super);
2254
2255         __setup_root(nodesize, leafsize, sectorsize, stripesize,
2256                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
2257
2258         chunk_root->node = read_tree_block(chunk_root,
2259                                            btrfs_super_chunk_root(disk_super),
2260                                            blocksize, generation);
2261         BUG_ON(!chunk_root->node);
2262         if (!test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
2263                 printk(KERN_WARNING "btrfs: failed to read chunk root on %s\n",
2264                        sb->s_id);
2265                 goto fail_tree_roots;
2266         }
2267         btrfs_set_root_node(&chunk_root->root_item, chunk_root->node);
2268         chunk_root->commit_root = btrfs_root_node(chunk_root);
2269
2270         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
2271            (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
2272            BTRFS_UUID_SIZE);
2273
2274         mutex_lock(&fs_info->chunk_mutex);
2275         ret = btrfs_read_chunk_tree(chunk_root);
2276         mutex_unlock(&fs_info->chunk_mutex);
2277         if (ret) {
2278                 printk(KERN_WARNING "btrfs: failed to read chunk tree on %s\n",
2279                        sb->s_id);
2280                 goto fail_tree_roots;
2281         }
2282
2283         btrfs_close_extra_devices(fs_devices);
2284
2285 retry_root_backup:
2286         blocksize = btrfs_level_size(tree_root,
2287                                      btrfs_super_root_level(disk_super));
2288         generation = btrfs_super_generation(disk_super);
2289
2290         tree_root->node = read_tree_block(tree_root,
2291                                           btrfs_super_root(disk_super),
2292                                           blocksize, generation);
2293         if (!tree_root->node ||
2294             !test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) {
2295                 printk(KERN_WARNING "btrfs: failed to read tree root on %s\n",
2296                        sb->s_id);
2297
2298                 goto recovery_tree_root;
2299         }
2300
2301         btrfs_set_root_node(&tree_root->root_item, tree_root->node);
2302         tree_root->commit_root = btrfs_root_node(tree_root);
2303
2304         ret = find_and_setup_root(tree_root, fs_info,
2305                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
2306         if (ret)
2307                 goto recovery_tree_root;
2308         extent_root->track_dirty = 1;
2309
2310         ret = find_and_setup_root(tree_root, fs_info,
2311                                   BTRFS_DEV_TREE_OBJECTID, dev_root);
2312         if (ret)
2313                 goto recovery_tree_root;
2314         dev_root->track_dirty = 1;
2315
2316         ret = find_and_setup_root(tree_root, fs_info,
2317                                   BTRFS_CSUM_TREE_OBJECTID, csum_root);
2318         if (ret)
2319                 goto recovery_tree_root;
2320
2321         csum_root->track_dirty = 1;
2322
2323         fs_info->generation = generation;
2324         fs_info->last_trans_committed = generation;
2325         fs_info->data_alloc_profile = (u64)-1;
2326         fs_info->metadata_alloc_profile = (u64)-1;
2327         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
2328
2329         ret = btrfs_init_space_info(fs_info);
2330         if (ret) {
2331                 printk(KERN_ERR "Failed to initial space info: %d\n", ret);
2332                 goto fail_block_groups;
2333         }
2334
2335         ret = btrfs_read_block_groups(extent_root);
2336         if (ret) {
2337                 printk(KERN_ERR "Failed to read block groups: %d\n", ret);
2338                 goto fail_block_groups;
2339         }
2340
2341         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
2342                                                "btrfs-cleaner");
2343         if (IS_ERR(fs_info->cleaner_kthread))
2344                 goto fail_block_groups;
2345
2346         fs_info->transaction_kthread = kthread_run(transaction_kthread,
2347                                                    tree_root,
2348                                                    "btrfs-transaction");
2349         if (IS_ERR(fs_info->transaction_kthread))
2350                 goto fail_cleaner;
2351
2352         if (!btrfs_test_opt(tree_root, SSD) &&
2353             !btrfs_test_opt(tree_root, NOSSD) &&
2354             !fs_info->fs_devices->rotating) {
2355                 printk(KERN_INFO "Btrfs detected SSD devices, enabling SSD "
2356                        "mode\n");
2357                 btrfs_set_opt(fs_info->mount_opt, SSD);
2358         }
2359
2360         /* do not make disk changes in broken FS */
2361         if (btrfs_super_log_root(disk_super) != 0 &&
2362             !(fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)) {
2363                 u64 bytenr = btrfs_super_log_root(disk_super);
2364
2365                 if (fs_devices->rw_devices == 0) {
2366                         printk(KERN_WARNING "Btrfs log replay required "
2367                                "on RO media\n");
2368                         err = -EIO;
2369                         goto fail_trans_kthread;
2370                 }
2371                 blocksize =
2372                      btrfs_level_size(tree_root,
2373                                       btrfs_super_log_root_level(disk_super));
2374
2375                 log_tree_root = btrfs_alloc_root(fs_info);
2376                 if (!log_tree_root) {
2377                         err = -ENOMEM;
2378                         goto fail_trans_kthread;
2379                 }
2380
2381                 __setup_root(nodesize, leafsize, sectorsize, stripesize,
2382                              log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
2383
2384                 log_tree_root->node = read_tree_block(tree_root, bytenr,
2385                                                       blocksize,
2386                                                       generation + 1);
2387                 ret = btrfs_recover_log_trees(log_tree_root);
2388                 BUG_ON(ret);
2389
2390                 if (sb->s_flags & MS_RDONLY) {
2391                         ret =  btrfs_commit_super(tree_root);
2392                         BUG_ON(ret);
2393                 }
2394         }
2395
2396         ret = btrfs_find_orphan_roots(tree_root);
2397         BUG_ON(ret);
2398
2399         if (!(sb->s_flags & MS_RDONLY)) {
2400                 ret = btrfs_cleanup_fs_roots(fs_info);
2401                 BUG_ON(ret);
2402
2403                 ret = btrfs_recover_relocation(tree_root);
2404                 if (ret < 0) {
2405                         printk(KERN_WARNING
2406                                "btrfs: failed to recover relocation\n");
2407                         err = -EINVAL;
2408                         goto fail_trans_kthread;
2409                 }
2410         }
2411
2412         location.objectid = BTRFS_FS_TREE_OBJECTID;
2413         location.type = BTRFS_ROOT_ITEM_KEY;
2414         location.offset = (u64)-1;
2415
2416         fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
2417         if (!fs_info->fs_root)
2418                 goto fail_trans_kthread;
2419         if (IS_ERR(fs_info->fs_root)) {
2420                 err = PTR_ERR(fs_info->fs_root);
2421                 goto fail_trans_kthread;
2422         }
2423
2424         if (!(sb->s_flags & MS_RDONLY)) {
2425                 down_read(&fs_info->cleanup_work_sem);
2426                 err = btrfs_orphan_cleanup(fs_info->fs_root);
2427                 if (!err)
2428                         err = btrfs_orphan_cleanup(fs_info->tree_root);
2429                 up_read(&fs_info->cleanup_work_sem);
2430                 if (err) {
2431                         close_ctree(tree_root);
2432                         return err;
2433                 }
2434         }
2435
2436         return 0;
2437
2438 fail_trans_kthread:
2439         kthread_stop(fs_info->transaction_kthread);
2440 fail_cleaner:
2441         kthread_stop(fs_info->cleaner_kthread);
2442
2443         /*
2444          * make sure we're done with the btree inode before we stop our
2445          * kthreads
2446          */
2447         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
2448         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2449
2450 fail_block_groups:
2451         btrfs_free_block_groups(fs_info);
2452
2453 fail_tree_roots:
2454         free_root_pointers(fs_info, 1);
2455
2456 fail_sb_buffer:
2457         btrfs_stop_workers(&fs_info->generic_worker);
2458         btrfs_stop_workers(&fs_info->readahead_workers);
2459         btrfs_stop_workers(&fs_info->fixup_workers);
2460         btrfs_stop_workers(&fs_info->delalloc_workers);
2461         btrfs_stop_workers(&fs_info->workers);
2462         btrfs_stop_workers(&fs_info->endio_workers);
2463         btrfs_stop_workers(&fs_info->endio_meta_workers);
2464         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
2465         btrfs_stop_workers(&fs_info->endio_write_workers);
2466         btrfs_stop_workers(&fs_info->endio_freespace_worker);
2467         btrfs_stop_workers(&fs_info->submit_workers);
2468         btrfs_stop_workers(&fs_info->delayed_workers);
2469         btrfs_stop_workers(&fs_info->caching_workers);
2470 fail_alloc:
2471 fail_iput:
2472         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2473
2474         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2475         iput(fs_info->btree_inode);
2476 fail_bdi:
2477         bdi_destroy(&fs_info->bdi);
2478 fail_srcu:
2479         cleanup_srcu_struct(&fs_info->subvol_srcu);
2480 fail:
2481         btrfs_close_devices(fs_info->fs_devices);
2482         return err;
2483
2484 recovery_tree_root:
2485         if (!btrfs_test_opt(tree_root, RECOVERY))
2486                 goto fail_tree_roots;
2487
2488         free_root_pointers(fs_info, 0);
2489
2490         /* don't use the log in recovery mode, it won't be valid */
2491         btrfs_set_super_log_root(disk_super, 0);
2492
2493         /* we can't trust the free space cache either */
2494         btrfs_set_opt(fs_info->mount_opt, CLEAR_CACHE);
2495
2496         ret = next_root_backup(fs_info, fs_info->super_copy,
2497                                &num_backups_tried, &backup_index);
2498         if (ret == -1)
2499                 goto fail_block_groups;
2500         goto retry_root_backup;
2501 }
2502
2503 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
2504 {
2505         char b[BDEVNAME_SIZE];
2506
2507         if (uptodate) {
2508                 set_buffer_uptodate(bh);
2509         } else {
2510                 printk_ratelimited(KERN_WARNING "lost page write due to "
2511                                         "I/O error on %s\n",
2512                                        bdevname(bh->b_bdev, b));
2513                 /* note, we dont' set_buffer_write_io_error because we have
2514                  * our own ways of dealing with the IO errors
2515                  */
2516                 clear_buffer_uptodate(bh);
2517         }
2518         unlock_buffer(bh);
2519         put_bh(bh);
2520 }
2521
2522 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
2523 {
2524         struct buffer_head *bh;
2525         struct buffer_head *latest = NULL;
2526         struct btrfs_super_block *super;
2527         int i;
2528         u64 transid = 0;
2529         u64 bytenr;
2530
2531         /* we would like to check all the supers, but that would make
2532          * a btrfs mount succeed after a mkfs from a different FS.
2533          * So, we need to add a special mount option to scan for
2534          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
2535          */
2536         for (i = 0; i < 1; i++) {
2537                 bytenr = btrfs_sb_offset(i);
2538                 if (bytenr + 4096 >= i_size_read(bdev->bd_inode))
2539                         break;
2540                 bh = __bread(bdev, bytenr / 4096, 4096);
2541                 if (!bh)
2542                         continue;
2543
2544                 super = (struct btrfs_super_block *)bh->b_data;
2545                 if (btrfs_super_bytenr(super) != bytenr ||
2546                     strncmp((char *)(&super->magic), BTRFS_MAGIC,
2547                             sizeof(super->magic))) {
2548                         brelse(bh);
2549                         continue;
2550                 }
2551
2552                 if (!latest || btrfs_super_generation(super) > transid) {
2553                         brelse(latest);
2554                         latest = bh;
2555                         transid = btrfs_super_generation(super);
2556                 } else {
2557                         brelse(bh);
2558                 }
2559         }
2560         return latest;
2561 }
2562
2563 /*
2564  * this should be called twice, once with wait == 0 and
2565  * once with wait == 1.  When wait == 0 is done, all the buffer heads
2566  * we write are pinned.
2567  *
2568  * They are released when wait == 1 is done.
2569  * max_mirrors must be the same for both runs, and it indicates how
2570  * many supers on this one device should be written.
2571  *
2572  * max_mirrors == 0 means to write them all.
2573  */
2574 static int write_dev_supers(struct btrfs_device *device,
2575                             struct btrfs_super_block *sb,
2576                             int do_barriers, int wait, int max_mirrors)
2577 {
2578         struct buffer_head *bh;
2579         int i;
2580         int ret;
2581         int errors = 0;
2582         u32 crc;
2583         u64 bytenr;
2584
2585         if (max_mirrors == 0)
2586                 max_mirrors = BTRFS_SUPER_MIRROR_MAX;
2587
2588         for (i = 0; i < max_mirrors; i++) {
2589                 bytenr = btrfs_sb_offset(i);
2590                 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
2591                         break;
2592
2593                 if (wait) {
2594                         bh = __find_get_block(device->bdev, bytenr / 4096,
2595                                               BTRFS_SUPER_INFO_SIZE);
2596                         BUG_ON(!bh);
2597                         wait_on_buffer(bh);
2598                         if (!buffer_uptodate(bh))
2599                                 errors++;
2600
2601                         /* drop our reference */
2602                         brelse(bh);
2603
2604                         /* drop the reference from the wait == 0 run */
2605                         brelse(bh);
2606                         continue;
2607                 } else {
2608                         btrfs_set_super_bytenr(sb, bytenr);
2609
2610                         crc = ~(u32)0;
2611                         crc = btrfs_csum_data(NULL, (char *)sb +
2612                                               BTRFS_CSUM_SIZE, crc,
2613                                               BTRFS_SUPER_INFO_SIZE -
2614                                               BTRFS_CSUM_SIZE);
2615                         btrfs_csum_final(crc, sb->csum);
2616
2617                         /*
2618                          * one reference for us, and we leave it for the
2619                          * caller
2620                          */
2621                         bh = __getblk(device->bdev, bytenr / 4096,
2622                                       BTRFS_SUPER_INFO_SIZE);
2623                         memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
2624
2625                         /* one reference for submit_bh */
2626                         get_bh(bh);
2627
2628                         set_buffer_uptodate(bh);
2629                         lock_buffer(bh);
2630                         bh->b_end_io = btrfs_end_buffer_write_sync;
2631                 }
2632
2633                 /*
2634                  * we fua the first super.  The others we allow
2635                  * to go down lazy.
2636                  */
2637                 ret = submit_bh(WRITE_FUA, bh);
2638                 if (ret)
2639                         errors++;
2640         }
2641         return errors < i ? 0 : -1;
2642 }
2643
2644 /*
2645  * endio for the write_dev_flush, this will wake anyone waiting
2646  * for the barrier when it is done
2647  */
2648 static void btrfs_end_empty_barrier(struct bio *bio, int err)
2649 {
2650         if (err) {
2651                 if (err == -EOPNOTSUPP)
2652                         set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
2653                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
2654         }
2655         if (bio->bi_private)
2656                 complete(bio->bi_private);
2657         bio_put(bio);
2658 }
2659
2660 /*
2661  * trigger flushes for one the devices.  If you pass wait == 0, the flushes are
2662  * sent down.  With wait == 1, it waits for the previous flush.
2663  *
2664  * any device where the flush fails with eopnotsupp are flagged as not-barrier
2665  * capable
2666  */
2667 static int write_dev_flush(struct btrfs_device *device, int wait)
2668 {
2669         struct bio *bio;
2670         int ret = 0;
2671
2672         if (device->nobarriers)
2673                 return 0;
2674
2675         if (wait) {
2676                 bio = device->flush_bio;
2677                 if (!bio)
2678                         return 0;
2679
2680                 wait_for_completion(&device->flush_wait);
2681
2682                 if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
2683                         printk("btrfs: disabling barriers on dev %s\n",
2684                                device->name);
2685                         device->nobarriers = 1;
2686                 }
2687                 if (!bio_flagged(bio, BIO_UPTODATE)) {
2688                         ret = -EIO;
2689                 }
2690
2691                 /* drop the reference from the wait == 0 run */
2692                 bio_put(bio);
2693                 device->flush_bio = NULL;
2694
2695                 return ret;
2696         }
2697
2698         /*
2699          * one reference for us, and we leave it for the
2700          * caller
2701          */
2702         device->flush_bio = NULL;;
2703         bio = bio_alloc(GFP_NOFS, 0);
2704         if (!bio)
2705                 return -ENOMEM;
2706
2707         bio->bi_end_io = btrfs_end_empty_barrier;
2708         bio->bi_bdev = device->bdev;
2709         init_completion(&device->flush_wait);
2710         bio->bi_private = &device->flush_wait;
2711         device->flush_bio = bio;
2712
2713         bio_get(bio);
2714         submit_bio(WRITE_FLUSH, bio);
2715
2716         return 0;
2717 }
2718
2719 /*
2720  * send an empty flush down to each device in parallel,
2721  * then wait for them
2722  */
2723 static int barrier_all_devices(struct btrfs_fs_info *info)
2724 {
2725         struct list_head *head;
2726         struct btrfs_device *dev;
2727         int errors = 0;
2728         int ret;
2729
2730         /* send down all the barriers */
2731         head = &info->fs_devices->devices;
2732         list_for_each_entry_rcu(dev, head, dev_list) {
2733                 if (!dev->bdev) {
2734                         errors++;
2735                         continue;
2736                 }
2737                 if (!dev->in_fs_metadata || !dev->writeable)
2738                         continue;
2739
2740                 ret = write_dev_flush(dev, 0);
2741                 if (ret)
2742                         errors++;
2743         }
2744
2745         /* wait for all the barriers */
2746         list_for_each_entry_rcu(dev, head, dev_list) {
2747                 if (!dev->bdev) {
2748                         errors++;
2749                         continue;
2750                 }
2751                 if (!dev->in_fs_metadata || !dev->writeable)
2752                         continue;
2753
2754                 ret = write_dev_flush(dev, 1);
2755                 if (ret)
2756                         errors++;
2757         }
2758         if (errors)
2759                 return -EIO;
2760         return 0;
2761 }
2762
2763 int write_all_supers(struct btrfs_root *root, int max_mirrors)
2764 {
2765         struct list_head *head;
2766         struct btrfs_device *dev;
2767         struct btrfs_super_block *sb;
2768         struct btrfs_dev_item *dev_item;
2769         int ret;
2770         int do_barriers;
2771         int max_errors;
2772         int total_errors = 0;
2773         u64 flags;
2774
2775         max_errors = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
2776         do_barriers = !btrfs_test_opt(root, NOBARRIER);
2777         backup_super_roots(root->fs_info);
2778
2779         sb = root->fs_info->super_for_commit;
2780         dev_item = &sb->dev_item;
2781
2782         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2783         head = &root->fs_info->fs_devices->devices;
2784
2785         if (do_barriers)
2786                 barrier_all_devices(root->fs_info);
2787
2788         list_for_each_entry_rcu(dev, head, dev_list) {
2789                 if (!dev->bdev) {
2790                         total_errors++;
2791                         continue;
2792                 }
2793                 if (!dev->in_fs_metadata || !dev->writeable)
2794                         continue;
2795
2796                 btrfs_set_stack_device_generation(dev_item, 0);
2797                 btrfs_set_stack_device_type(dev_item, dev->type);
2798                 btrfs_set_stack_device_id(dev_item, dev->devid);
2799                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
2800                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
2801                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
2802                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
2803                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
2804                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
2805                 memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
2806
2807                 flags = btrfs_super_flags(sb);
2808                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
2809
2810                 ret = write_dev_supers(dev, sb, do_barriers, 0, max_mirrors);
2811                 if (ret)
2812                         total_errors++;
2813         }
2814         if (total_errors > max_errors) {
2815                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2816                        total_errors);
2817                 BUG();
2818         }
2819
2820         total_errors = 0;
2821         list_for_each_entry_rcu(dev, head, dev_list) {
2822                 if (!dev->bdev)
2823                         continue;
2824                 if (!dev->in_fs_metadata || !dev->writeable)
2825                         continue;
2826
2827                 ret = write_dev_supers(dev, sb, do_barriers, 1, max_mirrors);
2828                 if (ret)
2829                         total_errors++;
2830         }
2831         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2832         if (total_errors > max_errors) {
2833                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2834                        total_errors);
2835                 BUG();
2836         }
2837         return 0;
2838 }
2839
2840 int write_ctree_super(struct btrfs_trans_handle *trans,
2841                       struct btrfs_root *root, int max_mirrors)
2842 {
2843         int ret;
2844
2845         ret = write_all_supers(root, max_mirrors);
2846         return ret;
2847 }
2848
2849 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2850 {
2851         spin_lock(&fs_info->fs_roots_radix_lock);
2852         radix_tree_delete(&fs_info->fs_roots_radix,
2853                           (unsigned long)root->root_key.objectid);
2854         spin_unlock(&fs_info->fs_roots_radix_lock);
2855
2856         if (btrfs_root_refs(&root->root_item) == 0)
2857                 synchronize_srcu(&fs_info->subvol_srcu);
2858
2859         __btrfs_remove_free_space_cache(root->free_ino_pinned);
2860         __btrfs_remove_free_space_cache(root->free_ino_ctl);
2861         free_fs_root(root);
2862         return 0;
2863 }
2864
2865 static void free_fs_root(struct btrfs_root *root)
2866 {
2867         iput(root->cache_inode);
2868         WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
2869         if (root->anon_dev)
2870                 free_anon_bdev(root->anon_dev);
2871         free_extent_buffer(root->node);
2872         free_extent_buffer(root->commit_root);
2873         kfree(root->free_ino_ctl);
2874         kfree(root->free_ino_pinned);
2875         kfree(root->name);
2876         kfree(root);
2877 }
2878
2879 static int del_fs_roots(struct btrfs_fs_info *fs_info)
2880 {
2881         int ret;
2882         struct btrfs_root *gang[8];
2883         int i;
2884
2885         while (!list_empty(&fs_info->dead_roots)) {
2886                 gang[0] = list_entry(fs_info->dead_roots.next,
2887                                      struct btrfs_root, root_list);
2888                 list_del(&gang[0]->root_list);
2889
2890                 if (gang[0]->in_radix) {
2891                         btrfs_free_fs_root(fs_info, gang[0]);
2892                 } else {
2893                         free_extent_buffer(gang[0]->node);
2894                         free_extent_buffer(gang[0]->commit_root);
2895                         kfree(gang[0]);
2896                 }
2897         }
2898
2899         while (1) {
2900                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2901                                              (void **)gang, 0,
2902                                              ARRAY_SIZE(gang));
2903                 if (!ret)
2904                         break;
2905                 for (i = 0; i < ret; i++)
2906                         btrfs_free_fs_root(fs_info, gang[i]);
2907         }
2908         return 0;
2909 }
2910
2911 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
2912 {
2913         u64 root_objectid = 0;
2914         struct btrfs_root *gang[8];
2915         int i;
2916         int ret;
2917
2918         while (1) {
2919                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2920                                              (void **)gang, root_objectid,
2921                                              ARRAY_SIZE(gang));
2922                 if (!ret)
2923                         break;
2924
2925                 root_objectid = gang[ret - 1]->root_key.objectid + 1;
2926                 for (i = 0; i < ret; i++) {
2927                         int err;
2928
2929                         root_objectid = gang[i]->root_key.objectid;
2930                         err = btrfs_orphan_cleanup(gang[i]);
2931                         if (err)
2932                                 return err;
2933                 }
2934                 root_objectid++;
2935         }
2936         return 0;
2937 }
2938
2939 int btrfs_commit_super(struct btrfs_root *root)
2940 {
2941         struct btrfs_trans_handle *trans;
2942         int ret;
2943
2944         mutex_lock(&root->fs_info->cleaner_mutex);
2945         btrfs_run_delayed_iputs(root);
2946         btrfs_clean_old_snapshots(root);
2947         mutex_unlock(&root->fs_info->cleaner_mutex);
2948
2949         /* wait until ongoing cleanup work done */
2950         down_write(&root->fs_info->cleanup_work_sem);
2951         up_write(&root->fs_info->cleanup_work_sem);
2952
2953         trans = btrfs_join_transaction(root);
2954         if (IS_ERR(trans))
2955                 return PTR_ERR(trans);
2956         ret = btrfs_commit_transaction(trans, root);
2957         BUG_ON(ret);
2958         /* run commit again to drop the original snapshot */
2959         trans = btrfs_join_transaction(root);
2960         if (IS_ERR(trans))
2961                 return PTR_ERR(trans);
2962         btrfs_commit_transaction(trans, root);
2963         ret = btrfs_write_and_wait_transaction(NULL, root);
2964         BUG_ON(ret);
2965
2966         ret = write_ctree_super(NULL, root, 0);
2967         return ret;
2968 }
2969
2970 int close_ctree(struct btrfs_root *root)
2971 {
2972         struct btrfs_fs_info *fs_info = root->fs_info;
2973         int ret;
2974
2975         fs_info->closing = 1;
2976         smp_mb();
2977
2978         btrfs_scrub_cancel(root);
2979
2980         /* wait for any defraggers to finish */
2981         wait_event(fs_info->transaction_wait,
2982                    (atomic_read(&fs_info->defrag_running) == 0));
2983
2984         /* clear out the rbtree of defraggable inodes */
2985         btrfs_run_defrag_inodes(fs_info);
2986
2987         /*
2988          * Here come 2 situations when btrfs is broken to flip readonly:
2989          *
2990          * 1. when btrfs flips readonly somewhere else before
2991          * btrfs_commit_super, sb->s_flags has MS_RDONLY flag,
2992          * and btrfs will skip to write sb directly to keep
2993          * ERROR state on disk.
2994          *
2995          * 2. when btrfs flips readonly just in btrfs_commit_super,
2996          * and in such case, btrfs cannot write sb via btrfs_commit_super,
2997          * and since fs_state has been set BTRFS_SUPER_FLAG_ERROR flag,
2998          * btrfs will cleanup all FS resources first and write sb then.
2999          */
3000         if (!(fs_info->sb->s_flags & MS_RDONLY)) {
3001                 ret = btrfs_commit_super(root);
3002                 if (ret)
3003                         printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
3004         }
3005
3006         if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
3007                 ret = btrfs_error_commit_super(root);
3008                 if (ret)
3009                         printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
3010         }
3011
3012         btrfs_put_block_group_cache(fs_info);
3013
3014         kthread_stop(fs_info->transaction_kthread);
3015         kthread_stop(fs_info->cleaner_kthread);
3016
3017         fs_info->closing = 2;
3018         smp_mb();
3019
3020         if (fs_info->delalloc_bytes) {
3021                 printk(KERN_INFO "btrfs: at unmount delalloc count %llu\n",
3022                        (unsigned long long)fs_info->delalloc_bytes);
3023         }
3024         if (fs_info->total_ref_cache_size) {
3025                 printk(KERN_INFO "btrfs: at umount reference cache size %llu\n",
3026                        (unsigned long long)fs_info->total_ref_cache_size);
3027         }
3028
3029         free_extent_buffer(fs_info->extent_root->node);
3030         free_extent_buffer(fs_info->extent_root->commit_root);
3031         free_extent_buffer(fs_info->tree_root->node);
3032         free_extent_buffer(fs_info->tree_root->commit_root);
3033         free_extent_buffer(fs_info->chunk_root->node);
3034         free_extent_buffer(fs_info->chunk_root->commit_root);
3035         free_extent_buffer(fs_info->dev_root->node);
3036         free_extent_buffer(fs_info->dev_root->commit_root);
3037         free_extent_buffer(fs_info->csum_root->node);
3038         free_extent_buffer(fs_info->csum_root->commit_root);
3039
3040         btrfs_free_block_groups(fs_info);
3041
3042         del_fs_roots(fs_info);
3043
3044         iput(fs_info->btree_inode);
3045
3046         btrfs_stop_workers(&fs_info->generic_worker);
3047         btrfs_stop_workers(&fs_info->fixup_workers);
3048         btrfs_stop_workers(&fs_info->delalloc_workers);
3049         btrfs_stop_workers(&fs_info->workers);
3050         btrfs_stop_workers(&fs_info->endio_workers);
3051         btrfs_stop_workers(&fs_info->endio_meta_workers);
3052         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
3053         btrfs_stop_workers(&fs_info->endio_write_workers);
3054         btrfs_stop_workers(&fs_info->endio_freespace_worker);
3055         btrfs_stop_workers(&fs_info->submit_workers);
3056         btrfs_stop_workers(&fs_info->delayed_workers);
3057         btrfs_stop_workers(&fs_info->caching_workers);
3058         btrfs_stop_workers(&fs_info->readahead_workers);
3059
3060         btrfs_close_devices(fs_info->fs_devices);
3061         btrfs_mapping_tree_free(&fs_info->mapping_tree);
3062
3063         bdi_destroy(&fs_info->bdi);
3064         cleanup_srcu_struct(&fs_info->subvol_srcu);
3065
3066         return 0;
3067 }
3068
3069 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
3070 {
3071         int ret;
3072         struct inode *btree_inode = buf->first_page->mapping->host;
3073
3074         ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf,
3075                                      NULL);
3076         if (!ret)
3077                 return ret;
3078
3079         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
3080                                     parent_transid);
3081         return !ret;
3082 }
3083
3084 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
3085 {
3086         struct inode *btree_inode = buf->first_page->mapping->host;
3087         return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
3088                                           buf);
3089 }
3090
3091 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
3092 {
3093         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
3094         u64 transid = btrfs_header_generation(buf);
3095         struct inode *btree_inode = root->fs_info->btree_inode;
3096         int was_dirty;
3097
3098         btrfs_assert_tree_locked(buf);
3099         if (transid != root->fs_info->generation) {
3100                 printk(KERN_CRIT "btrfs transid mismatch buffer %llu, "
3101                        "found %llu running %llu\n",
3102                         (unsigned long long)buf->start,
3103                         (unsigned long long)transid,
3104                         (unsigned long long)root->fs_info->generation);
3105                 WARN_ON(1);
3106         }
3107         was_dirty = set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
3108                                             buf);
3109         if (!was_dirty) {
3110                 spin_lock(&root->fs_info->delalloc_lock);
3111                 root->fs_info->dirty_metadata_bytes += buf->len;
3112                 spin_unlock(&root->fs_info->delalloc_lock);
3113         }
3114 }
3115
3116 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
3117 {
3118         /*
3119          * looks as though older kernels can get into trouble with
3120          * this code, they end up stuck in balance_dirty_pages forever
3121          */
3122         u64 num_dirty;
3123         unsigned long thresh = 32 * 1024 * 1024;
3124
3125         if (current->flags & PF_MEMALLOC)
3126                 return;
3127
3128         btrfs_balance_delayed_items(root);
3129
3130         num_dirty = root->fs_info->dirty_metadata_bytes;
3131
3132         if (num_dirty > thresh) {
3133                 balance_dirty_pages_ratelimited_nr(
3134                                    root->fs_info->btree_inode->i_mapping, 1);
3135         }
3136         return;
3137 }
3138
3139 void __btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
3140 {
3141         /*
3142          * looks as though older kernels can get into trouble with
3143          * this code, they end up stuck in balance_dirty_pages forever
3144          */
3145         u64 num_dirty;
3146         unsigned long thresh = 32 * 1024 * 1024;
3147
3148         if (current->flags & PF_MEMALLOC)
3149                 return;
3150
3151         num_dirty = root->fs_info->dirty_metadata_bytes;
3152
3153         if (num_dirty > thresh) {
3154                 balance_dirty_pages_ratelimited_nr(
3155                                    root->fs_info->btree_inode->i_mapping, 1);
3156         }
3157         return;
3158 }
3159
3160 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
3161 {
3162         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
3163         int ret;
3164         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
3165         if (ret == 0)
3166                 set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
3167         return ret;
3168 }
3169
3170 static int btree_lock_page_hook(struct page *page, void *data,
3171                                 void (*flush_fn)(void *))
3172 {
3173         struct inode *inode = page->mapping->host;
3174         struct btrfs_root *root = BTRFS_I(inode)->root;
3175         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3176         struct extent_buffer *eb;
3177         unsigned long len;
3178         u64 bytenr = page_offset(page);
3179
3180         if (page->private == EXTENT_PAGE_PRIVATE)
3181                 goto out;
3182
3183         len = page->private >> 2;
3184         eb = find_extent_buffer(io_tree, bytenr, len);
3185         if (!eb)
3186                 goto out;
3187
3188         if (!btrfs_try_tree_write_lock(eb)) {
3189                 flush_fn(data);
3190                 btrfs_tree_lock(eb);
3191         }
3192         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3193
3194         if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3195                 spin_lock(&root->fs_info->delalloc_lock);
3196                 if (root->fs_info->dirty_metadata_bytes >= eb->len)
3197                         root->fs_info->dirty_metadata_bytes -= eb->len;
3198                 else
3199                         WARN_ON(1);
3200                 spin_unlock(&root->fs_info->delalloc_lock);
3201         }
3202
3203         btrfs_tree_unlock(eb);
3204         free_extent_buffer(eb);
3205 out:
3206         if (!trylock_page(page)) {
3207                 flush_fn(data);
3208                 lock_page(page);
3209         }
3210         return 0;
3211 }
3212
3213 static void btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
3214                               int read_only)
3215 {
3216         if (read_only)
3217                 return;
3218
3219         if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
3220                 printk(KERN_WARNING "warning: mount fs with errors, "
3221                        "running btrfsck is recommended\n");
3222 }
3223
3224 int btrfs_error_commit_super(struct btrfs_root *root)
3225 {
3226         int ret;
3227
3228         mutex_lock(&root->fs_info->cleaner_mutex);
3229         btrfs_run_delayed_iputs(root);
3230         mutex_unlock(&root->fs_info->cleaner_mutex);
3231
3232         down_write(&root->fs_info->cleanup_work_sem);
3233         up_write(&root->fs_info->cleanup_work_sem);
3234
3235         /* cleanup FS via transaction */
3236         btrfs_cleanup_transaction(root);
3237
3238         ret = write_ctree_super(NULL, root, 0);
3239
3240         return ret;
3241 }
3242
3243 static int btrfs_destroy_ordered_operations(struct btrfs_root *root)
3244 {
3245         struct btrfs_inode *btrfs_inode;
3246         struct list_head splice;
3247
3248         INIT_LIST_HEAD(&splice);
3249
3250         mutex_lock(&root->fs_info->ordered_operations_mutex);
3251         spin_lock(&root->fs_info->ordered_extent_lock);
3252
3253         list_splice_init(&root->fs_info->ordered_operations, &splice);
3254         while (!list_empty(&splice)) {
3255                 btrfs_inode = list_entry(splice.next, struct btrfs_inode,
3256                                          ordered_operations);
3257
3258                 list_del_init(&btrfs_inode->ordered_operations);
3259
3260                 btrfs_invalidate_inodes(btrfs_inode->root);
3261         }
3262
3263         spin_unlock(&root->fs_info->ordered_extent_lock);
3264         mutex_unlock(&root->fs_info->ordered_operations_mutex);
3265
3266         return 0;
3267 }
3268
3269 static int btrfs_destroy_ordered_extents(struct btrfs_root *root)
3270 {
3271         struct list_head splice;
3272         struct btrfs_ordered_extent *ordered;
3273         struct inode *inode;
3274
3275         INIT_LIST_HEAD(&splice);
3276
3277         spin_lock(&root->fs_info->ordered_extent_lock);
3278
3279         list_splice_init(&root->fs_info->ordered_extents, &splice);
3280         while (!list_empty(&splice)) {
3281                 ordered = list_entry(splice.next, struct btrfs_ordered_extent,
3282                                      root_extent_list);
3283
3284                 list_del_init(&ordered->root_extent_list);
3285                 atomic_inc(&ordered->refs);
3286
3287                 /* the inode may be getting freed (in sys_unlink path). */
3288                 inode = igrab(ordered->inode);
3289
3290                 spin_unlock(&root->fs_info->ordered_extent_lock);
3291                 if (inode)
3292                         iput(inode);
3293
3294                 atomic_set(&ordered->refs, 1);
3295                 btrfs_put_ordered_extent(ordered);
3296
3297                 spin_lock(&root->fs_info->ordered_extent_lock);
3298         }
3299
3300         spin_unlock(&root->fs_info->ordered_extent_lock);
3301
3302         return 0;
3303 }
3304
3305 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
3306                                       struct btrfs_root *root)
3307 {
3308         struct rb_node *node;
3309         struct btrfs_delayed_ref_root *delayed_refs;
3310         struct btrfs_delayed_ref_node *ref;
3311         int ret = 0;
3312
3313         delayed_refs = &trans->delayed_refs;
3314
3315         spin_lock(&delayed_refs->lock);
3316         if (delayed_refs->num_entries == 0) {
3317                 spin_unlock(&delayed_refs->lock);
3318                 printk(KERN_INFO "delayed_refs has NO entry\n");
3319                 return ret;
3320         }
3321
3322         node = rb_first(&delayed_refs->root);
3323         while (node) {
3324                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
3325                 node = rb_next(node);
3326
3327                 ref->in_tree = 0;
3328                 rb_erase(&ref->rb_node, &delayed_refs->root);
3329                 delayed_refs->num_entries--;
3330
3331                 atomic_set(&ref->refs, 1);
3332                 if (btrfs_delayed_ref_is_head(ref)) {
3333                         struct btrfs_delayed_ref_head *head;
3334
3335                         head = btrfs_delayed_node_to_head(ref);
3336                         mutex_lock(&head->mutex);
3337                         kfree(head->extent_op);
3338                         delayed_refs->num_heads--;
3339                         if (list_empty(&head->cluster))
3340                                 delayed_refs->num_heads_ready--;
3341                         list_del_init(&head->cluster);
3342                         mutex_unlock(&head->mutex);
3343                 }
3344
3345                 spin_unlock(&delayed_refs->lock);
3346                 btrfs_put_delayed_ref(ref);
3347
3348                 cond_resched();
3349                 spin_lock(&delayed_refs->lock);
3350         }
3351
3352         spin_unlock(&delayed_refs->lock);
3353
3354         return ret;
3355 }
3356
3357 static int btrfs_destroy_pending_snapshots(struct btrfs_transaction *t)
3358 {
3359         struct btrfs_pending_snapshot *snapshot;
3360         struct list_head splice;
3361
3362         INIT_LIST_HEAD(&splice);
3363
3364         list_splice_init(&t->pending_snapshots, &splice);
3365
3366         while (!list_empty(&splice)) {
3367                 snapshot = list_entry(splice.next,
3368                                       struct btrfs_pending_snapshot,
3369                                       list);
3370
3371                 list_del_init(&snapshot->list);
3372
3373                 kfree(snapshot);
3374         }
3375
3376         return 0;
3377 }
3378
3379 static int btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
3380 {
3381         struct btrfs_inode *btrfs_inode;
3382     &nb