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

Version: ~ [ linux-5.4 ] ~ [ linux-5.3.13 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.86 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.156 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.203 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.202 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.78 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

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

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