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TOMOYO Linux Cross Reference
Linux/fs/btrfs/ordered-data.c

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  1 /*
  2  * Copyright (C) 2007 Oracle.  All rights reserved.
  3  *
  4  * This program is free software; you can redistribute it and/or
  5  * modify it under the terms of the GNU General Public
  6  * License v2 as published by the Free Software Foundation.
  7  *
  8  * This program is distributed in the hope that it will be useful,
  9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 11  * General Public License for more details.
 12  *
 13  * You should have received a copy of the GNU General Public
 14  * License along with this program; if not, write to the
 15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 16  * Boston, MA 021110-1307, USA.
 17  */
 18 
 19 #include <linux/slab.h>
 20 #include <linux/blkdev.h>
 21 #include <linux/writeback.h>
 22 #include <linux/pagevec.h>
 23 #include "ctree.h"
 24 #include "transaction.h"
 25 #include "btrfs_inode.h"
 26 #include "extent_io.h"
 27 #include "disk-io.h"
 28 #include "compression.h"
 29 
 30 static struct kmem_cache *btrfs_ordered_extent_cache;
 31 
 32 static u64 entry_end(struct btrfs_ordered_extent *entry)
 33 {
 34         if (entry->file_offset + entry->len < entry->file_offset)
 35                 return (u64)-1;
 36         return entry->file_offset + entry->len;
 37 }
 38 
 39 /* returns NULL if the insertion worked, or it returns the node it did find
 40  * in the tree
 41  */
 42 static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
 43                                    struct rb_node *node)
 44 {
 45         struct rb_node **p = &root->rb_node;
 46         struct rb_node *parent = NULL;
 47         struct btrfs_ordered_extent *entry;
 48 
 49         while (*p) {
 50                 parent = *p;
 51                 entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
 52 
 53                 if (file_offset < entry->file_offset)
 54                         p = &(*p)->rb_left;
 55                 else if (file_offset >= entry_end(entry))
 56                         p = &(*p)->rb_right;
 57                 else
 58                         return parent;
 59         }
 60 
 61         rb_link_node(node, parent, p);
 62         rb_insert_color(node, root);
 63         return NULL;
 64 }
 65 
 66 static void ordered_data_tree_panic(struct inode *inode, int errno,
 67                                                u64 offset)
 68 {
 69         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 70         btrfs_panic(fs_info, errno,
 71                     "Inconsistency in ordered tree at offset %llu", offset);
 72 }
 73 
 74 /*
 75  * look for a given offset in the tree, and if it can't be found return the
 76  * first lesser offset
 77  */
 78 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
 79                                      struct rb_node **prev_ret)
 80 {
 81         struct rb_node *n = root->rb_node;
 82         struct rb_node *prev = NULL;
 83         struct rb_node *test;
 84         struct btrfs_ordered_extent *entry;
 85         struct btrfs_ordered_extent *prev_entry = NULL;
 86 
 87         while (n) {
 88                 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
 89                 prev = n;
 90                 prev_entry = entry;
 91 
 92                 if (file_offset < entry->file_offset)
 93                         n = n->rb_left;
 94                 else if (file_offset >= entry_end(entry))
 95                         n = n->rb_right;
 96                 else
 97                         return n;
 98         }
 99         if (!prev_ret)
100                 return NULL;
101 
102         while (prev && file_offset >= entry_end(prev_entry)) {
103                 test = rb_next(prev);
104                 if (!test)
105                         break;
106                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
107                                       rb_node);
108                 if (file_offset < entry_end(prev_entry))
109                         break;
110 
111                 prev = test;
112         }
113         if (prev)
114                 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
115                                       rb_node);
116         while (prev && file_offset < entry_end(prev_entry)) {
117                 test = rb_prev(prev);
118                 if (!test)
119                         break;
120                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
121                                       rb_node);
122                 prev = test;
123         }
124         *prev_ret = prev;
125         return NULL;
126 }
127 
128 /*
129  * helper to check if a given offset is inside a given entry
130  */
131 static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
132 {
133         if (file_offset < entry->file_offset ||
134             entry->file_offset + entry->len <= file_offset)
135                 return 0;
136         return 1;
137 }
138 
139 static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
140                           u64 len)
141 {
142         if (file_offset + len <= entry->file_offset ||
143             entry->file_offset + entry->len <= file_offset)
144                 return 0;
145         return 1;
146 }
147 
148 /*
149  * look find the first ordered struct that has this offset, otherwise
150  * the first one less than this offset
151  */
152 static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
153                                           u64 file_offset)
154 {
155         struct rb_root *root = &tree->tree;
156         struct rb_node *prev = NULL;
157         struct rb_node *ret;
158         struct btrfs_ordered_extent *entry;
159 
160         if (tree->last) {
161                 entry = rb_entry(tree->last, struct btrfs_ordered_extent,
162                                  rb_node);
163                 if (offset_in_entry(entry, file_offset))
164                         return tree->last;
165         }
166         ret = __tree_search(root, file_offset, &prev);
167         if (!ret)
168                 ret = prev;
169         if (ret)
170                 tree->last = ret;
171         return ret;
172 }
173 
174 /* allocate and add a new ordered_extent into the per-inode tree.
175  * file_offset is the logical offset in the file
176  *
177  * start is the disk block number of an extent already reserved in the
178  * extent allocation tree
179  *
180  * len is the length of the extent
181  *
182  * The tree is given a single reference on the ordered extent that was
183  * inserted.
184  */
185 static int __btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
186                                       u64 start, u64 len, u64 disk_len,
187                                       int type, int dio, int compress_type)
188 {
189         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
190         struct btrfs_root *root = BTRFS_I(inode)->root;
191         struct btrfs_ordered_inode_tree *tree;
192         struct rb_node *node;
193         struct btrfs_ordered_extent *entry;
194 
195         tree = &BTRFS_I(inode)->ordered_tree;
196         entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
197         if (!entry)
198                 return -ENOMEM;
199 
200         entry->file_offset = file_offset;
201         entry->start = start;
202         entry->len = len;
203         entry->disk_len = disk_len;
204         entry->bytes_left = len;
205         entry->inode = igrab(inode);
206         entry->compress_type = compress_type;
207         entry->truncated_len = (u64)-1;
208         if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
209                 set_bit(type, &entry->flags);
210 
211         if (dio)
212                 set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
213 
214         /* one ref for the tree */
215         refcount_set(&entry->refs, 1);
216         init_waitqueue_head(&entry->wait);
217         INIT_LIST_HEAD(&entry->list);
218         INIT_LIST_HEAD(&entry->root_extent_list);
219         INIT_LIST_HEAD(&entry->work_list);
220         init_completion(&entry->completion);
221         INIT_LIST_HEAD(&entry->log_list);
222         INIT_LIST_HEAD(&entry->trans_list);
223 
224         trace_btrfs_ordered_extent_add(inode, entry);
225 
226         spin_lock_irq(&tree->lock);
227         node = tree_insert(&tree->tree, file_offset,
228                            &entry->rb_node);
229         if (node)
230                 ordered_data_tree_panic(inode, -EEXIST, file_offset);
231         spin_unlock_irq(&tree->lock);
232 
233         spin_lock(&root->ordered_extent_lock);
234         list_add_tail(&entry->root_extent_list,
235                       &root->ordered_extents);
236         root->nr_ordered_extents++;
237         if (root->nr_ordered_extents == 1) {
238                 spin_lock(&fs_info->ordered_root_lock);
239                 BUG_ON(!list_empty(&root->ordered_root));
240                 list_add_tail(&root->ordered_root, &fs_info->ordered_roots);
241                 spin_unlock(&fs_info->ordered_root_lock);
242         }
243         spin_unlock(&root->ordered_extent_lock);
244 
245         /*
246          * We don't need the count_max_extents here, we can assume that all of
247          * that work has been done at higher layers, so this is truly the
248          * smallest the extent is going to get.
249          */
250         spin_lock(&BTRFS_I(inode)->lock);
251         btrfs_mod_outstanding_extents(BTRFS_I(inode), 1);
252         spin_unlock(&BTRFS_I(inode)->lock);
253 
254         return 0;
255 }
256 
257 int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
258                              u64 start, u64 len, u64 disk_len, int type)
259 {
260         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
261                                           disk_len, type, 0,
262                                           BTRFS_COMPRESS_NONE);
263 }
264 
265 int btrfs_add_ordered_extent_dio(struct inode *inode, u64 file_offset,
266                                  u64 start, u64 len, u64 disk_len, int type)
267 {
268         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
269                                           disk_len, type, 1,
270                                           BTRFS_COMPRESS_NONE);
271 }
272 
273 int btrfs_add_ordered_extent_compress(struct inode *inode, u64 file_offset,
274                                       u64 start, u64 len, u64 disk_len,
275                                       int type, int compress_type)
276 {
277         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
278                                           disk_len, type, 0,
279                                           compress_type);
280 }
281 
282 /*
283  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
284  * when an ordered extent is finished.  If the list covers more than one
285  * ordered extent, it is split across multiples.
286  */
287 void btrfs_add_ordered_sum(struct inode *inode,
288                            struct btrfs_ordered_extent *entry,
289                            struct btrfs_ordered_sum *sum)
290 {
291         struct btrfs_ordered_inode_tree *tree;
292 
293         tree = &BTRFS_I(inode)->ordered_tree;
294         spin_lock_irq(&tree->lock);
295         list_add_tail(&sum->list, &entry->list);
296         spin_unlock_irq(&tree->lock);
297 }
298 
299 /*
300  * this is used to account for finished IO across a given range
301  * of the file.  The IO may span ordered extents.  If
302  * a given ordered_extent is completely done, 1 is returned, otherwise
303  * 0.
304  *
305  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
306  * to make sure this function only returns 1 once for a given ordered extent.
307  *
308  * file_offset is updated to one byte past the range that is recorded as
309  * complete.  This allows you to walk forward in the file.
310  */
311 int btrfs_dec_test_first_ordered_pending(struct inode *inode,
312                                    struct btrfs_ordered_extent **cached,
313                                    u64 *file_offset, u64 io_size, int uptodate)
314 {
315         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
316         struct btrfs_ordered_inode_tree *tree;
317         struct rb_node *node;
318         struct btrfs_ordered_extent *entry = NULL;
319         int ret;
320         unsigned long flags;
321         u64 dec_end;
322         u64 dec_start;
323         u64 to_dec;
324 
325         tree = &BTRFS_I(inode)->ordered_tree;
326         spin_lock_irqsave(&tree->lock, flags);
327         node = tree_search(tree, *file_offset);
328         if (!node) {
329                 ret = 1;
330                 goto out;
331         }
332 
333         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
334         if (!offset_in_entry(entry, *file_offset)) {
335                 ret = 1;
336                 goto out;
337         }
338 
339         dec_start = max(*file_offset, entry->file_offset);
340         dec_end = min(*file_offset + io_size, entry->file_offset +
341                       entry->len);
342         *file_offset = dec_end;
343         if (dec_start > dec_end) {
344                 btrfs_crit(fs_info, "bad ordering dec_start %llu end %llu",
345                            dec_start, dec_end);
346         }
347         to_dec = dec_end - dec_start;
348         if (to_dec > entry->bytes_left) {
349                 btrfs_crit(fs_info,
350                            "bad ordered accounting left %llu size %llu",
351                            entry->bytes_left, to_dec);
352         }
353         entry->bytes_left -= to_dec;
354         if (!uptodate)
355                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
356 
357         if (entry->bytes_left == 0) {
358                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
359                 /*
360                  * Implicit memory barrier after test_and_set_bit
361                  */
362                 if (waitqueue_active(&entry->wait))
363                         wake_up(&entry->wait);
364         } else {
365                 ret = 1;
366         }
367 out:
368         if (!ret && cached && entry) {
369                 *cached = entry;
370                 refcount_inc(&entry->refs);
371         }
372         spin_unlock_irqrestore(&tree->lock, flags);
373         return ret == 0;
374 }
375 
376 /*
377  * this is used to account for finished IO across a given range
378  * of the file.  The IO should not span ordered extents.  If
379  * a given ordered_extent is completely done, 1 is returned, otherwise
380  * 0.
381  *
382  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
383  * to make sure this function only returns 1 once for a given ordered extent.
384  */
385 int btrfs_dec_test_ordered_pending(struct inode *inode,
386                                    struct btrfs_ordered_extent **cached,
387                                    u64 file_offset, u64 io_size, int uptodate)
388 {
389         struct btrfs_ordered_inode_tree *tree;
390         struct rb_node *node;
391         struct btrfs_ordered_extent *entry = NULL;
392         unsigned long flags;
393         int ret;
394 
395         tree = &BTRFS_I(inode)->ordered_tree;
396         spin_lock_irqsave(&tree->lock, flags);
397         if (cached && *cached) {
398                 entry = *cached;
399                 goto have_entry;
400         }
401 
402         node = tree_search(tree, file_offset);
403         if (!node) {
404                 ret = 1;
405                 goto out;
406         }
407 
408         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
409 have_entry:
410         if (!offset_in_entry(entry, file_offset)) {
411                 ret = 1;
412                 goto out;
413         }
414 
415         if (io_size > entry->bytes_left) {
416                 btrfs_crit(BTRFS_I(inode)->root->fs_info,
417                            "bad ordered accounting left %llu size %llu",
418                        entry->bytes_left, io_size);
419         }
420         entry->bytes_left -= io_size;
421         if (!uptodate)
422                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
423 
424         if (entry->bytes_left == 0) {
425                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
426                 /*
427                  * Implicit memory barrier after test_and_set_bit
428                  */
429                 if (waitqueue_active(&entry->wait))
430                         wake_up(&entry->wait);
431         } else {
432                 ret = 1;
433         }
434 out:
435         if (!ret && cached && entry) {
436                 *cached = entry;
437                 refcount_inc(&entry->refs);
438         }
439         spin_unlock_irqrestore(&tree->lock, flags);
440         return ret == 0;
441 }
442 
443 /* Needs to either be called under a log transaction or the log_mutex */
444 void btrfs_get_logged_extents(struct btrfs_inode *inode,
445                               struct list_head *logged_list,
446                               const loff_t start,
447                               const loff_t end)
448 {
449         struct btrfs_ordered_inode_tree *tree;
450         struct btrfs_ordered_extent *ordered;
451         struct rb_node *n;
452         struct rb_node *prev;
453 
454         tree = &inode->ordered_tree;
455         spin_lock_irq(&tree->lock);
456         n = __tree_search(&tree->tree, end, &prev);
457         if (!n)
458                 n = prev;
459         for (; n; n = rb_prev(n)) {
460                 ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
461                 if (ordered->file_offset > end)
462                         continue;
463                 if (entry_end(ordered) <= start)
464                         break;
465                 if (test_and_set_bit(BTRFS_ORDERED_LOGGED, &ordered->flags))
466                         continue;
467                 list_add(&ordered->log_list, logged_list);
468                 refcount_inc(&ordered->refs);
469         }
470         spin_unlock_irq(&tree->lock);
471 }
472 
473 void btrfs_put_logged_extents(struct list_head *logged_list)
474 {
475         struct btrfs_ordered_extent *ordered;
476 
477         while (!list_empty(logged_list)) {
478                 ordered = list_first_entry(logged_list,
479                                            struct btrfs_ordered_extent,
480                                            log_list);
481                 list_del_init(&ordered->log_list);
482                 btrfs_put_ordered_extent(ordered);
483         }
484 }
485 
486 void btrfs_submit_logged_extents(struct list_head *logged_list,
487                                  struct btrfs_root *log)
488 {
489         int index = log->log_transid % 2;
490 
491         spin_lock_irq(&log->log_extents_lock[index]);
492         list_splice_tail(logged_list, &log->logged_list[index]);
493         spin_unlock_irq(&log->log_extents_lock[index]);
494 }
495 
496 void btrfs_wait_logged_extents(struct btrfs_trans_handle *trans,
497                                struct btrfs_root *log, u64 transid)
498 {
499         struct btrfs_ordered_extent *ordered;
500         int index = transid % 2;
501 
502         spin_lock_irq(&log->log_extents_lock[index]);
503         while (!list_empty(&log->logged_list[index])) {
504                 struct inode *inode;
505                 ordered = list_first_entry(&log->logged_list[index],
506                                            struct btrfs_ordered_extent,
507                                            log_list);
508                 list_del_init(&ordered->log_list);
509                 inode = ordered->inode;
510                 spin_unlock_irq(&log->log_extents_lock[index]);
511 
512                 if (!test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags) &&
513                     !test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags)) {
514                         u64 start = ordered->file_offset;
515                         u64 end = ordered->file_offset + ordered->len - 1;
516 
517                         WARN_ON(!inode);
518                         filemap_fdatawrite_range(inode->i_mapping, start, end);
519                 }
520                 wait_event(ordered->wait, test_bit(BTRFS_ORDERED_IO_DONE,
521                                                    &ordered->flags));
522 
523                 /*
524                  * In order to keep us from losing our ordered extent
525                  * information when committing the transaction we have to make
526                  * sure that any logged extents are completed when we go to
527                  * commit the transaction.  To do this we simply increase the
528                  * current transactions pending_ordered counter and decrement it
529                  * when the ordered extent completes.
530                  */
531                 if (!test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags)) {
532                         struct btrfs_ordered_inode_tree *tree;
533 
534                         tree = &BTRFS_I(inode)->ordered_tree;
535                         spin_lock_irq(&tree->lock);
536                         if (!test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags)) {
537                                 set_bit(BTRFS_ORDERED_PENDING, &ordered->flags);
538                                 atomic_inc(&trans->transaction->pending_ordered);
539                         }
540                         spin_unlock_irq(&tree->lock);
541                 }
542                 btrfs_put_ordered_extent(ordered);
543                 spin_lock_irq(&log->log_extents_lock[index]);
544         }
545         spin_unlock_irq(&log->log_extents_lock[index]);
546 }
547 
548 void btrfs_free_logged_extents(struct btrfs_root *log, u64 transid)
549 {
550         struct btrfs_ordered_extent *ordered;
551         int index = transid % 2;
552 
553         spin_lock_irq(&log->log_extents_lock[index]);
554         while (!list_empty(&log->logged_list[index])) {
555                 ordered = list_first_entry(&log->logged_list[index],
556                                            struct btrfs_ordered_extent,
557                                            log_list);
558                 list_del_init(&ordered->log_list);
559                 spin_unlock_irq(&log->log_extents_lock[index]);
560                 btrfs_put_ordered_extent(ordered);
561                 spin_lock_irq(&log->log_extents_lock[index]);
562         }
563         spin_unlock_irq(&log->log_extents_lock[index]);
564 }
565 
566 /*
567  * used to drop a reference on an ordered extent.  This will free
568  * the extent if the last reference is dropped
569  */
570 void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
571 {
572         struct list_head *cur;
573         struct btrfs_ordered_sum *sum;
574 
575         trace_btrfs_ordered_extent_put(entry->inode, entry);
576 
577         if (refcount_dec_and_test(&entry->refs)) {
578                 ASSERT(list_empty(&entry->log_list));
579                 ASSERT(list_empty(&entry->trans_list));
580                 ASSERT(list_empty(&entry->root_extent_list));
581                 ASSERT(RB_EMPTY_NODE(&entry->rb_node));
582                 if (entry->inode)
583                         btrfs_add_delayed_iput(entry->inode);
584                 while (!list_empty(&entry->list)) {
585                         cur = entry->list.next;
586                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
587                         list_del(&sum->list);
588                         kfree(sum);
589                 }
590                 kmem_cache_free(btrfs_ordered_extent_cache, entry);
591         }
592 }
593 
594 /*
595  * remove an ordered extent from the tree.  No references are dropped
596  * and waiters are woken up.
597  */
598 void btrfs_remove_ordered_extent(struct inode *inode,
599                                  struct btrfs_ordered_extent *entry)
600 {
601         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
602         struct btrfs_ordered_inode_tree *tree;
603         struct btrfs_inode *btrfs_inode = BTRFS_I(inode);
604         struct btrfs_root *root = btrfs_inode->root;
605         struct rb_node *node;
606         bool dec_pending_ordered = false;
607 
608         /* This is paired with btrfs_add_ordered_extent. */
609         spin_lock(&btrfs_inode->lock);
610         btrfs_mod_outstanding_extents(btrfs_inode, -1);
611         spin_unlock(&btrfs_inode->lock);
612         if (root != fs_info->tree_root)
613                 btrfs_delalloc_release_metadata(btrfs_inode, entry->len);
614 
615         tree = &btrfs_inode->ordered_tree;
616         spin_lock_irq(&tree->lock);
617         node = &entry->rb_node;
618         rb_erase(node, &tree->tree);
619         RB_CLEAR_NODE(node);
620         if (tree->last == node)
621                 tree->last = NULL;
622         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
623         if (test_and_clear_bit(BTRFS_ORDERED_PENDING, &entry->flags))
624                 dec_pending_ordered = true;
625         spin_unlock_irq(&tree->lock);
626 
627         /*
628          * The current running transaction is waiting on us, we need to let it
629          * know that we're complete and wake it up.
630          */
631         if (dec_pending_ordered) {
632                 struct btrfs_transaction *trans;
633 
634                 /*
635                  * The checks for trans are just a formality, it should be set,
636                  * but if it isn't we don't want to deref/assert under the spin
637                  * lock, so be nice and check if trans is set, but ASSERT() so
638                  * if it isn't set a developer will notice.
639                  */
640                 spin_lock(&fs_info->trans_lock);
641                 trans = fs_info->running_transaction;
642                 if (trans)
643                         refcount_inc(&trans->use_count);
644                 spin_unlock(&fs_info->trans_lock);
645 
646                 ASSERT(trans);
647                 if (trans) {
648                         if (atomic_dec_and_test(&trans->pending_ordered))
649                                 wake_up(&trans->pending_wait);
650                         btrfs_put_transaction(trans);
651                 }
652         }
653 
654         spin_lock(&root->ordered_extent_lock);
655         list_del_init(&entry->root_extent_list);
656         root->nr_ordered_extents--;
657 
658         trace_btrfs_ordered_extent_remove(inode, entry);
659 
660         if (!root->nr_ordered_extents) {
661                 spin_lock(&fs_info->ordered_root_lock);
662                 BUG_ON(list_empty(&root->ordered_root));
663                 list_del_init(&root->ordered_root);
664                 spin_unlock(&fs_info->ordered_root_lock);
665         }
666         spin_unlock(&root->ordered_extent_lock);
667         wake_up(&entry->wait);
668 }
669 
670 static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
671 {
672         struct btrfs_ordered_extent *ordered;
673 
674         ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
675         btrfs_start_ordered_extent(ordered->inode, ordered, 1);
676         complete(&ordered->completion);
677 }
678 
679 /*
680  * wait for all the ordered extents in a root.  This is done when balancing
681  * space between drives.
682  */
683 u64 btrfs_wait_ordered_extents(struct btrfs_root *root, u64 nr,
684                                const u64 range_start, const u64 range_len)
685 {
686         struct btrfs_fs_info *fs_info = root->fs_info;
687         LIST_HEAD(splice);
688         LIST_HEAD(skipped);
689         LIST_HEAD(works);
690         struct btrfs_ordered_extent *ordered, *next;
691         u64 count = 0;
692         const u64 range_end = range_start + range_len;
693 
694         mutex_lock(&root->ordered_extent_mutex);
695         spin_lock(&root->ordered_extent_lock);
696         list_splice_init(&root->ordered_extents, &splice);
697         while (!list_empty(&splice) && nr) {
698                 ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
699                                            root_extent_list);
700 
701                 if (range_end <= ordered->start ||
702                     ordered->start + ordered->disk_len <= range_start) {
703                         list_move_tail(&ordered->root_extent_list, &skipped);
704                         cond_resched_lock(&root->ordered_extent_lock);
705                         continue;
706                 }
707 
708                 list_move_tail(&ordered->root_extent_list,
709                                &root->ordered_extents);
710                 refcount_inc(&ordered->refs);
711                 spin_unlock(&root->ordered_extent_lock);
712 
713                 btrfs_init_work(&ordered->flush_work,
714                                 btrfs_flush_delalloc_helper,
715                                 btrfs_run_ordered_extent_work, NULL, NULL);
716                 list_add_tail(&ordered->work_list, &works);
717                 btrfs_queue_work(fs_info->flush_workers, &ordered->flush_work);
718 
719                 cond_resched();
720                 spin_lock(&root->ordered_extent_lock);
721                 if (nr != U64_MAX)
722                         nr--;
723                 count++;
724         }
725         list_splice_tail(&skipped, &root->ordered_extents);
726         list_splice_tail(&splice, &root->ordered_extents);
727         spin_unlock(&root->ordered_extent_lock);
728 
729         list_for_each_entry_safe(ordered, next, &works, work_list) {
730                 list_del_init(&ordered->work_list);
731                 wait_for_completion(&ordered->completion);
732                 btrfs_put_ordered_extent(ordered);
733                 cond_resched();
734         }
735         mutex_unlock(&root->ordered_extent_mutex);
736 
737         return count;
738 }
739 
740 u64 btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, u64 nr,
741                              const u64 range_start, const u64 range_len)
742 {
743         struct btrfs_root *root;
744         struct list_head splice;
745         u64 total_done = 0;
746         u64 done;
747 
748         INIT_LIST_HEAD(&splice);
749 
750         mutex_lock(&fs_info->ordered_operations_mutex);
751         spin_lock(&fs_info->ordered_root_lock);
752         list_splice_init(&fs_info->ordered_roots, &splice);
753         while (!list_empty(&splice) && nr) {
754                 root = list_first_entry(&splice, struct btrfs_root,
755                                         ordered_root);
756                 root = btrfs_grab_fs_root(root);
757                 BUG_ON(!root);
758                 list_move_tail(&root->ordered_root,
759                                &fs_info->ordered_roots);
760                 spin_unlock(&fs_info->ordered_root_lock);
761 
762                 done = btrfs_wait_ordered_extents(root, nr,
763                                                   range_start, range_len);
764                 btrfs_put_fs_root(root);
765                 total_done += done;
766 
767                 spin_lock(&fs_info->ordered_root_lock);
768                 if (nr != U64_MAX) {
769                         nr -= done;
770                 }
771         }
772         list_splice_tail(&splice, &fs_info->ordered_roots);
773         spin_unlock(&fs_info->ordered_root_lock);
774         mutex_unlock(&fs_info->ordered_operations_mutex);
775 
776         return total_done;
777 }
778 
779 /*
780  * Used to start IO or wait for a given ordered extent to finish.
781  *
782  * If wait is one, this effectively waits on page writeback for all the pages
783  * in the extent, and it waits on the io completion code to insert
784  * metadata into the btree corresponding to the extent
785  */
786 void btrfs_start_ordered_extent(struct inode *inode,
787                                        struct btrfs_ordered_extent *entry,
788                                        int wait)
789 {
790         u64 start = entry->file_offset;
791         u64 end = start + entry->len - 1;
792 
793         trace_btrfs_ordered_extent_start(inode, entry);
794 
795         /*
796          * pages in the range can be dirty, clean or writeback.  We
797          * start IO on any dirty ones so the wait doesn't stall waiting
798          * for the flusher thread to find them
799          */
800         if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
801                 filemap_fdatawrite_range(inode->i_mapping, start, end);
802         if (wait) {
803                 wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
804                                                  &entry->flags));
805         }
806 }
807 
808 /*
809  * Used to wait on ordered extents across a large range of bytes.
810  */
811 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
812 {
813         int ret = 0;
814         int ret_wb = 0;
815         u64 end;
816         u64 orig_end;
817         struct btrfs_ordered_extent *ordered;
818 
819         if (start + len < start) {
820                 orig_end = INT_LIMIT(loff_t);
821         } else {
822                 orig_end = start + len - 1;
823                 if (orig_end > INT_LIMIT(loff_t))
824                         orig_end = INT_LIMIT(loff_t);
825         }
826 
827         /* start IO across the range first to instantiate any delalloc
828          * extents
829          */
830         ret = btrfs_fdatawrite_range(inode, start, orig_end);
831         if (ret)
832                 return ret;
833 
834         /*
835          * If we have a writeback error don't return immediately. Wait first
836          * for any ordered extents that haven't completed yet. This is to make
837          * sure no one can dirty the same page ranges and call writepages()
838          * before the ordered extents complete - to avoid failures (-EEXIST)
839          * when adding the new ordered extents to the ordered tree.
840          */
841         ret_wb = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
842 
843         end = orig_end;
844         while (1) {
845                 ordered = btrfs_lookup_first_ordered_extent(inode, end);
846                 if (!ordered)
847                         break;
848                 if (ordered->file_offset > orig_end) {
849                         btrfs_put_ordered_extent(ordered);
850                         break;
851                 }
852                 if (ordered->file_offset + ordered->len <= start) {
853                         btrfs_put_ordered_extent(ordered);
854                         break;
855                 }
856                 btrfs_start_ordered_extent(inode, ordered, 1);
857                 end = ordered->file_offset;
858                 if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
859                         ret = -EIO;
860                 btrfs_put_ordered_extent(ordered);
861                 if (ret || end == 0 || end == start)
862                         break;
863                 end--;
864         }
865         return ret_wb ? ret_wb : ret;
866 }
867 
868 /*
869  * find an ordered extent corresponding to file_offset.  return NULL if
870  * nothing is found, otherwise take a reference on the extent and return it
871  */
872 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
873                                                          u64 file_offset)
874 {
875         struct btrfs_ordered_inode_tree *tree;
876         struct rb_node *node;
877         struct btrfs_ordered_extent *entry = NULL;
878 
879         tree = &BTRFS_I(inode)->ordered_tree;
880         spin_lock_irq(&tree->lock);
881         node = tree_search(tree, file_offset);
882         if (!node)
883                 goto out;
884 
885         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
886         if (!offset_in_entry(entry, file_offset))
887                 entry = NULL;
888         if (entry)
889                 refcount_inc(&entry->refs);
890 out:
891         spin_unlock_irq(&tree->lock);
892         return entry;
893 }
894 
895 /* Since the DIO code tries to lock a wide area we need to look for any ordered
896  * extents that exist in the range, rather than just the start of the range.
897  */
898 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(
899                 struct btrfs_inode *inode, u64 file_offset, u64 len)
900 {
901         struct btrfs_ordered_inode_tree *tree;
902         struct rb_node *node;
903         struct btrfs_ordered_extent *entry = NULL;
904 
905         tree = &inode->ordered_tree;
906         spin_lock_irq(&tree->lock);
907         node = tree_search(tree, file_offset);
908         if (!node) {
909                 node = tree_search(tree, file_offset + len);
910                 if (!node)
911                         goto out;
912         }
913 
914         while (1) {
915                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
916                 if (range_overlaps(entry, file_offset, len))
917                         break;
918 
919                 if (entry->file_offset >= file_offset + len) {
920                         entry = NULL;
921                         break;
922                 }
923                 entry = NULL;
924                 node = rb_next(node);
925                 if (!node)
926                         break;
927         }
928 out:
929         if (entry)
930                 refcount_inc(&entry->refs);
931         spin_unlock_irq(&tree->lock);
932         return entry;
933 }
934 
935 bool btrfs_have_ordered_extents_in_range(struct inode *inode,
936                                          u64 file_offset,
937                                          u64 len)
938 {
939         struct btrfs_ordered_extent *oe;
940 
941         oe = btrfs_lookup_ordered_range(BTRFS_I(inode), file_offset, len);
942         if (oe) {
943                 btrfs_put_ordered_extent(oe);
944                 return true;
945         }
946         return false;
947 }
948 
949 /*
950  * lookup and return any extent before 'file_offset'.  NULL is returned
951  * if none is found
952  */
953 struct btrfs_ordered_extent *
954 btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
955 {
956         struct btrfs_ordered_inode_tree *tree;
957         struct rb_node *node;
958         struct btrfs_ordered_extent *entry = NULL;
959 
960         tree = &BTRFS_I(inode)->ordered_tree;
961         spin_lock_irq(&tree->lock);
962         node = tree_search(tree, file_offset);
963         if (!node)
964                 goto out;
965 
966         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
967         refcount_inc(&entry->refs);
968 out:
969         spin_unlock_irq(&tree->lock);
970         return entry;
971 }
972 
973 /*
974  * After an extent is done, call this to conditionally update the on disk
975  * i_size.  i_size is updated to cover any fully written part of the file.
976  */
977 int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
978                                 struct btrfs_ordered_extent *ordered)
979 {
980         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
981         u64 disk_i_size;
982         u64 new_i_size;
983         u64 i_size = i_size_read(inode);
984         struct rb_node *node;
985         struct rb_node *prev = NULL;
986         struct btrfs_ordered_extent *test;
987         int ret = 1;
988         u64 orig_offset = offset;
989 
990         spin_lock_irq(&tree->lock);
991         if (ordered) {
992                 offset = entry_end(ordered);
993                 if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags))
994                         offset = min(offset,
995                                      ordered->file_offset +
996                                      ordered->truncated_len);
997         } else {
998                 offset = ALIGN(offset, btrfs_inode_sectorsize(inode));
999         }
1000         disk_i_size = BTRFS_I(inode)->disk_i_size;
1001 
1002         /*
1003          * truncate file.
1004          * If ordered is not NULL, then this is called from endio and
1005          * disk_i_size will be updated by either truncate itself or any
1006          * in-flight IOs which are inside the disk_i_size.
1007          *
1008          * Because btrfs_setsize() may set i_size with disk_i_size if truncate
1009          * fails somehow, we need to make sure we have a precise disk_i_size by
1010          * updating it as usual.
1011          *
1012          */
1013         if (!ordered && disk_i_size > i_size) {
1014                 BTRFS_I(inode)->disk_i_size = orig_offset;
1015                 ret = 0;
1016                 goto out;
1017         }
1018 
1019         /*
1020          * if the disk i_size is already at the inode->i_size, or
1021          * this ordered extent is inside the disk i_size, we're done
1022          */
1023         if (disk_i_size == i_size)
1024                 goto out;
1025 
1026         /*
1027          * We still need to update disk_i_size if outstanding_isize is greater
1028          * than disk_i_size.
1029          */
1030         if (offset <= disk_i_size &&
1031             (!ordered || ordered->outstanding_isize <= disk_i_size))
1032                 goto out;
1033 
1034         /*
1035          * walk backward from this ordered extent to disk_i_size.
1036          * if we find an ordered extent then we can't update disk i_size
1037          * yet
1038          */
1039         if (ordered) {
1040                 node = rb_prev(&ordered->rb_node);
1041         } else {
1042                 prev = tree_search(tree, offset);
1043                 /*
1044                  * we insert file extents without involving ordered struct,
1045                  * so there should be no ordered struct cover this offset
1046                  */
1047                 if (prev) {
1048                         test = rb_entry(prev, struct btrfs_ordered_extent,
1049                                         rb_node);
1050                         BUG_ON(offset_in_entry(test, offset));
1051                 }
1052                 node = prev;
1053         }
1054         for (; node; node = rb_prev(node)) {
1055                 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
1056 
1057                 /* We treat this entry as if it doesn't exist */
1058                 if (test_bit(BTRFS_ORDERED_UPDATED_ISIZE, &test->flags))
1059                         continue;
1060 
1061                 if (entry_end(test) <= disk_i_size)
1062                         break;
1063                 if (test->file_offset >= i_size)
1064                         break;
1065 
1066                 /*
1067                  * We don't update disk_i_size now, so record this undealt
1068                  * i_size. Or we will not know the real i_size.
1069                  */
1070                 if (test->outstanding_isize < offset)
1071                         test->outstanding_isize = offset;
1072                 if (ordered &&
1073                     ordered->outstanding_isize > test->outstanding_isize)
1074                         test->outstanding_isize = ordered->outstanding_isize;
1075                 goto out;
1076         }
1077         new_i_size = min_t(u64, offset, i_size);
1078 
1079         /*
1080          * Some ordered extents may completed before the current one, and
1081          * we hold the real i_size in ->outstanding_isize.
1082          */
1083         if (ordered && ordered->outstanding_isize > new_i_size)
1084                 new_i_size = min_t(u64, ordered->outstanding_isize, i_size);
1085         BTRFS_I(inode)->disk_i_size = new_i_size;
1086         ret = 0;
1087 out:
1088         /*
1089          * We need to do this because we can't remove ordered extents until
1090          * after the i_disk_size has been updated and then the inode has been
1091          * updated to reflect the change, so we need to tell anybody who finds
1092          * this ordered extent that we've already done all the real work, we
1093          * just haven't completed all the other work.
1094          */
1095         if (ordered)
1096                 set_bit(BTRFS_ORDERED_UPDATED_ISIZE, &ordered->flags);
1097         spin_unlock_irq(&tree->lock);
1098         return ret;
1099 }
1100 
1101 /*
1102  * search the ordered extents for one corresponding to 'offset' and
1103  * try to find a checksum.  This is used because we allow pages to
1104  * be reclaimed before their checksum is actually put into the btree
1105  */
1106 int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
1107                            u32 *sum, int len)
1108 {
1109         struct btrfs_ordered_sum *ordered_sum;
1110         struct btrfs_ordered_extent *ordered;
1111         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
1112         unsigned long num_sectors;
1113         unsigned long i;
1114         u32 sectorsize = btrfs_inode_sectorsize(inode);
1115         int index = 0;
1116 
1117         ordered = btrfs_lookup_ordered_extent(inode, offset);
1118         if (!ordered)
1119                 return 0;
1120 
1121         spin_lock_irq(&tree->lock);
1122         list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
1123                 if (disk_bytenr >= ordered_sum->bytenr &&
1124                     disk_bytenr < ordered_sum->bytenr + ordered_sum->len) {
1125                         i = (disk_bytenr - ordered_sum->bytenr) >>
1126                             inode->i_sb->s_blocksize_bits;
1127                         num_sectors = ordered_sum->len >>
1128                                       inode->i_sb->s_blocksize_bits;
1129                         num_sectors = min_t(int, len - index, num_sectors - i);
1130                         memcpy(sum + index, ordered_sum->sums + i,
1131                                num_sectors);
1132 
1133                         index += (int)num_sectors;
1134                         if (index == len)
1135                                 goto out;
1136                         disk_bytenr += num_sectors * sectorsize;
1137                 }
1138         }
1139 out:
1140         spin_unlock_irq(&tree->lock);
1141         btrfs_put_ordered_extent(ordered);
1142         return index;
1143 }
1144 
1145 int __init ordered_data_init(void)
1146 {
1147         btrfs_ordered_extent_cache = kmem_cache_create("btrfs_ordered_extent",
1148                                      sizeof(struct btrfs_ordered_extent), 0,
1149                                      SLAB_MEM_SPREAD,
1150                                      NULL);
1151         if (!btrfs_ordered_extent_cache)
1152                 return -ENOMEM;
1153 
1154         return 0;
1155 }
1156 
1157 void ordered_data_exit(void)
1158 {
1159         kmem_cache_destroy(btrfs_ordered_extent_cache);
1160 }
1161 

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