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David Woodhouse53b381b2013-01-29 18:40:14 -05001/*
2 * Copyright (C) 2012 Fusion-io All rights reserved.
3 * Copyright (C) 2012 Intel Corp. All rights reserved.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public
7 * License v2 as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public
15 * License along with this program; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 021110-1307, USA.
18 */
19#include <linux/sched.h>
20#include <linux/wait.h>
21#include <linux/bio.h>
22#include <linux/slab.h>
23#include <linux/buffer_head.h>
24#include <linux/blkdev.h>
25#include <linux/random.h>
26#include <linux/iocontext.h>
27#include <linux/capability.h>
28#include <linux/ratelimit.h>
29#include <linux/kthread.h>
30#include <linux/raid/pq.h>
31#include <linux/hash.h>
32#include <linux/list_sort.h>
33#include <linux/raid/xor.h>
Geert Uytterhoevend7011f52013-03-03 04:44:41 -070034#include <linux/vmalloc.h>
David Woodhouse53b381b2013-01-29 18:40:14 -050035#include <asm/div64.h>
David Woodhouse53b381b2013-01-29 18:40:14 -050036#include "ctree.h"
37#include "extent_map.h"
38#include "disk-io.h"
39#include "transaction.h"
40#include "print-tree.h"
41#include "volumes.h"
42#include "raid56.h"
43#include "async-thread.h"
44#include "check-integrity.h"
45#include "rcu-string.h"
46
47/* set when additional merges to this rbio are not allowed */
48#define RBIO_RMW_LOCKED_BIT 1
49
Chris Mason4ae10b32013-01-31 14:42:09 -050050/*
51 * set when this rbio is sitting in the hash, but it is just a cache
52 * of past RMW
53 */
54#define RBIO_CACHE_BIT 2
55
56/*
57 * set when it is safe to trust the stripe_pages for caching
58 */
59#define RBIO_CACHE_READY_BIT 3
60
Chris Mason4ae10b32013-01-31 14:42:09 -050061#define RBIO_CACHE_SIZE 1024
62
Miao Xie1b94b552014-11-06 16:14:21 +080063enum btrfs_rbio_ops {
64 BTRFS_RBIO_WRITE = 0,
65 BTRFS_RBIO_READ_REBUILD = 1,
Miao Xie5a6ac9e2014-11-06 17:20:58 +080066 BTRFS_RBIO_PARITY_SCRUB = 2,
Miao Xie1b94b552014-11-06 16:14:21 +080067};
68
David Woodhouse53b381b2013-01-29 18:40:14 -050069struct btrfs_raid_bio {
70 struct btrfs_fs_info *fs_info;
71 struct btrfs_bio *bbio;
72
David Woodhouse53b381b2013-01-29 18:40:14 -050073 /* while we're doing rmw on a stripe
74 * we put it into a hash table so we can
75 * lock the stripe and merge more rbios
76 * into it.
77 */
78 struct list_head hash_list;
79
80 /*
Chris Mason4ae10b32013-01-31 14:42:09 -050081 * LRU list for the stripe cache
82 */
83 struct list_head stripe_cache;
84
85 /*
David Woodhouse53b381b2013-01-29 18:40:14 -050086 * for scheduling work in the helper threads
87 */
88 struct btrfs_work work;
89
90 /*
91 * bio list and bio_list_lock are used
92 * to add more bios into the stripe
93 * in hopes of avoiding the full rmw
94 */
95 struct bio_list bio_list;
96 spinlock_t bio_list_lock;
97
Chris Mason6ac0f482013-01-31 14:42:28 -050098 /* also protected by the bio_list_lock, the
99 * plug list is used by the plugging code
100 * to collect partial bios while plugged. The
101 * stripe locking code also uses it to hand off
David Woodhouse53b381b2013-01-29 18:40:14 -0500102 * the stripe lock to the next pending IO
103 */
104 struct list_head plug_list;
105
106 /*
107 * flags that tell us if it is safe to
108 * merge with this bio
109 */
110 unsigned long flags;
111
112 /* size of each individual stripe on disk */
113 int stripe_len;
114
115 /* number of data stripes (no p/q) */
116 int nr_data;
117
Miao Xie2c8cdd62014-11-14 16:06:25 +0800118 int real_stripes;
119
Miao Xie5a6ac9e2014-11-06 17:20:58 +0800120 int stripe_npages;
David Woodhouse53b381b2013-01-29 18:40:14 -0500121 /*
122 * set if we're doing a parity rebuild
123 * for a read from higher up, which is handled
124 * differently from a parity rebuild as part of
125 * rmw
126 */
Miao Xie1b94b552014-11-06 16:14:21 +0800127 enum btrfs_rbio_ops operation;
David Woodhouse53b381b2013-01-29 18:40:14 -0500128
129 /* first bad stripe */
130 int faila;
131
132 /* second bad stripe (for raid6 use) */
133 int failb;
134
Miao Xie5a6ac9e2014-11-06 17:20:58 +0800135 int scrubp;
David Woodhouse53b381b2013-01-29 18:40:14 -0500136 /*
137 * number of pages needed to represent the full
138 * stripe
139 */
140 int nr_pages;
141
142 /*
143 * size of all the bios in the bio_list. This
144 * helps us decide if the rbio maps to a full
145 * stripe or not
146 */
147 int bio_list_bytes;
148
Miao Xie42452152014-11-25 16:39:28 +0800149 int generic_bio_cnt;
150
David Woodhouse53b381b2013-01-29 18:40:14 -0500151 atomic_t refs;
152
Miao Xieb89e1b02014-10-15 11:18:44 +0800153 atomic_t stripes_pending;
154
155 atomic_t error;
David Woodhouse53b381b2013-01-29 18:40:14 -0500156 /*
157 * these are two arrays of pointers. We allocate the
158 * rbio big enough to hold them both and setup their
159 * locations when the rbio is allocated
160 */
161
162 /* pointers to pages that we allocated for
163 * reading/writing stripes directly from the disk (including P/Q)
164 */
165 struct page **stripe_pages;
166
167 /*
168 * pointers to the pages in the bio_list. Stored
169 * here for faster lookup
170 */
171 struct page **bio_pages;
Miao Xie5a6ac9e2014-11-06 17:20:58 +0800172
173 /*
174 * bitmap to record which horizontal stripe has data
175 */
176 unsigned long *dbitmap;
David Woodhouse53b381b2013-01-29 18:40:14 -0500177};
178
179static int __raid56_parity_recover(struct btrfs_raid_bio *rbio);
180static noinline void finish_rmw(struct btrfs_raid_bio *rbio);
181static void rmw_work(struct btrfs_work *work);
182static void read_rebuild_work(struct btrfs_work *work);
183static void async_rmw_stripe(struct btrfs_raid_bio *rbio);
184static void async_read_rebuild(struct btrfs_raid_bio *rbio);
185static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio);
186static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed);
187static void __free_raid_bio(struct btrfs_raid_bio *rbio);
188static void index_rbio_pages(struct btrfs_raid_bio *rbio);
189static int alloc_rbio_pages(struct btrfs_raid_bio *rbio);
190
Miao Xie5a6ac9e2014-11-06 17:20:58 +0800191static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
192 int need_check);
193static void async_scrub_parity(struct btrfs_raid_bio *rbio);
194
David Woodhouse53b381b2013-01-29 18:40:14 -0500195/*
196 * the stripe hash table is used for locking, and to collect
197 * bios in hopes of making a full stripe
198 */
199int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info)
200{
201 struct btrfs_stripe_hash_table *table;
202 struct btrfs_stripe_hash_table *x;
203 struct btrfs_stripe_hash *cur;
204 struct btrfs_stripe_hash *h;
205 int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS;
206 int i;
David Sterba83c82662013-03-01 15:03:00 +0000207 int table_size;
David Woodhouse53b381b2013-01-29 18:40:14 -0500208
209 if (info->stripe_hash_table)
210 return 0;
211
David Sterba83c82662013-03-01 15:03:00 +0000212 /*
213 * The table is large, starting with order 4 and can go as high as
214 * order 7 in case lock debugging is turned on.
215 *
216 * Try harder to allocate and fallback to vmalloc to lower the chance
217 * of a failing mount.
218 */
219 table_size = sizeof(*table) + sizeof(*h) * num_entries;
220 table = kzalloc(table_size, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
221 if (!table) {
222 table = vzalloc(table_size);
223 if (!table)
224 return -ENOMEM;
225 }
David Woodhouse53b381b2013-01-29 18:40:14 -0500226
Chris Mason4ae10b32013-01-31 14:42:09 -0500227 spin_lock_init(&table->cache_lock);
228 INIT_LIST_HEAD(&table->stripe_cache);
229
David Woodhouse53b381b2013-01-29 18:40:14 -0500230 h = table->table;
231
232 for (i = 0; i < num_entries; i++) {
233 cur = h + i;
234 INIT_LIST_HEAD(&cur->hash_list);
235 spin_lock_init(&cur->lock);
236 init_waitqueue_head(&cur->wait);
237 }
238
239 x = cmpxchg(&info->stripe_hash_table, NULL, table);
Wang Shilongf7493032014-11-22 21:13:10 +0800240 if (x)
241 kvfree(x);
David Woodhouse53b381b2013-01-29 18:40:14 -0500242 return 0;
243}
244
245/*
Chris Mason4ae10b32013-01-31 14:42:09 -0500246 * caching an rbio means to copy anything from the
247 * bio_pages array into the stripe_pages array. We
248 * use the page uptodate bit in the stripe cache array
249 * to indicate if it has valid data
250 *
251 * once the caching is done, we set the cache ready
252 * bit.
253 */
254static void cache_rbio_pages(struct btrfs_raid_bio *rbio)
255{
256 int i;
257 char *s;
258 char *d;
259 int ret;
260
261 ret = alloc_rbio_pages(rbio);
262 if (ret)
263 return;
264
265 for (i = 0; i < rbio->nr_pages; i++) {
266 if (!rbio->bio_pages[i])
267 continue;
268
269 s = kmap(rbio->bio_pages[i]);
270 d = kmap(rbio->stripe_pages[i]);
271
272 memcpy(d, s, PAGE_CACHE_SIZE);
273
274 kunmap(rbio->bio_pages[i]);
275 kunmap(rbio->stripe_pages[i]);
276 SetPageUptodate(rbio->stripe_pages[i]);
277 }
278 set_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
279}
280
281/*
David Woodhouse53b381b2013-01-29 18:40:14 -0500282 * we hash on the first logical address of the stripe
283 */
284static int rbio_bucket(struct btrfs_raid_bio *rbio)
285{
Zhao Lei8e5cfb52015-01-20 15:11:33 +0800286 u64 num = rbio->bbio->raid_map[0];
David Woodhouse53b381b2013-01-29 18:40:14 -0500287
288 /*
289 * we shift down quite a bit. We're using byte
290 * addressing, and most of the lower bits are zeros.
291 * This tends to upset hash_64, and it consistently
292 * returns just one or two different values.
293 *
294 * shifting off the lower bits fixes things.
295 */
296 return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS);
297}
298
299/*
Chris Mason4ae10b32013-01-31 14:42:09 -0500300 * stealing an rbio means taking all the uptodate pages from the stripe
301 * array in the source rbio and putting them into the destination rbio
302 */
303static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest)
304{
305 int i;
306 struct page *s;
307 struct page *d;
308
309 if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags))
310 return;
311
312 for (i = 0; i < dest->nr_pages; i++) {
313 s = src->stripe_pages[i];
314 if (!s || !PageUptodate(s)) {
315 continue;
316 }
317
318 d = dest->stripe_pages[i];
319 if (d)
320 __free_page(d);
321
322 dest->stripe_pages[i] = s;
323 src->stripe_pages[i] = NULL;
324 }
325}
326
327/*
David Woodhouse53b381b2013-01-29 18:40:14 -0500328 * merging means we take the bio_list from the victim and
329 * splice it into the destination. The victim should
330 * be discarded afterwards.
331 *
332 * must be called with dest->rbio_list_lock held
333 */
334static void merge_rbio(struct btrfs_raid_bio *dest,
335 struct btrfs_raid_bio *victim)
336{
337 bio_list_merge(&dest->bio_list, &victim->bio_list);
338 dest->bio_list_bytes += victim->bio_list_bytes;
Miao Xie42452152014-11-25 16:39:28 +0800339 dest->generic_bio_cnt += victim->generic_bio_cnt;
David Woodhouse53b381b2013-01-29 18:40:14 -0500340 bio_list_init(&victim->bio_list);
341}
342
343/*
Chris Mason4ae10b32013-01-31 14:42:09 -0500344 * used to prune items that are in the cache. The caller
345 * must hold the hash table lock.
346 */
347static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
348{
349 int bucket = rbio_bucket(rbio);
350 struct btrfs_stripe_hash_table *table;
351 struct btrfs_stripe_hash *h;
352 int freeit = 0;
353
354 /*
355 * check the bit again under the hash table lock.
356 */
357 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
358 return;
359
360 table = rbio->fs_info->stripe_hash_table;
361 h = table->table + bucket;
362
363 /* hold the lock for the bucket because we may be
364 * removing it from the hash table
365 */
366 spin_lock(&h->lock);
367
368 /*
369 * hold the lock for the bio list because we need
370 * to make sure the bio list is empty
371 */
372 spin_lock(&rbio->bio_list_lock);
373
374 if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) {
375 list_del_init(&rbio->stripe_cache);
376 table->cache_size -= 1;
377 freeit = 1;
378
379 /* if the bio list isn't empty, this rbio is
380 * still involved in an IO. We take it out
381 * of the cache list, and drop the ref that
382 * was held for the list.
383 *
384 * If the bio_list was empty, we also remove
385 * the rbio from the hash_table, and drop
386 * the corresponding ref
387 */
388 if (bio_list_empty(&rbio->bio_list)) {
389 if (!list_empty(&rbio->hash_list)) {
390 list_del_init(&rbio->hash_list);
391 atomic_dec(&rbio->refs);
392 BUG_ON(!list_empty(&rbio->plug_list));
393 }
394 }
395 }
396
397 spin_unlock(&rbio->bio_list_lock);
398 spin_unlock(&h->lock);
399
400 if (freeit)
401 __free_raid_bio(rbio);
402}
403
404/*
405 * prune a given rbio from the cache
406 */
407static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio)
408{
409 struct btrfs_stripe_hash_table *table;
410 unsigned long flags;
411
412 if (!test_bit(RBIO_CACHE_BIT, &rbio->flags))
413 return;
414
415 table = rbio->fs_info->stripe_hash_table;
416
417 spin_lock_irqsave(&table->cache_lock, flags);
418 __remove_rbio_from_cache(rbio);
419 spin_unlock_irqrestore(&table->cache_lock, flags);
420}
421
422/*
423 * remove everything in the cache
424 */
Eric Sandeen48a3b632013-04-25 20:41:01 +0000425static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info)
Chris Mason4ae10b32013-01-31 14:42:09 -0500426{
427 struct btrfs_stripe_hash_table *table;
428 unsigned long flags;
429 struct btrfs_raid_bio *rbio;
430
431 table = info->stripe_hash_table;
432
433 spin_lock_irqsave(&table->cache_lock, flags);
434 while (!list_empty(&table->stripe_cache)) {
435 rbio = list_entry(table->stripe_cache.next,
436 struct btrfs_raid_bio,
437 stripe_cache);
438 __remove_rbio_from_cache(rbio);
439 }
440 spin_unlock_irqrestore(&table->cache_lock, flags);
441}
442
443/*
444 * remove all cached entries and free the hash table
445 * used by unmount
David Woodhouse53b381b2013-01-29 18:40:14 -0500446 */
447void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info)
448{
449 if (!info->stripe_hash_table)
450 return;
Chris Mason4ae10b32013-01-31 14:42:09 -0500451 btrfs_clear_rbio_cache(info);
Wang Shilongf7493032014-11-22 21:13:10 +0800452 kvfree(info->stripe_hash_table);
David Woodhouse53b381b2013-01-29 18:40:14 -0500453 info->stripe_hash_table = NULL;
454}
455
456/*
Chris Mason4ae10b32013-01-31 14:42:09 -0500457 * insert an rbio into the stripe cache. It
458 * must have already been prepared by calling
459 * cache_rbio_pages
460 *
461 * If this rbio was already cached, it gets
462 * moved to the front of the lru.
463 *
464 * If the size of the rbio cache is too big, we
465 * prune an item.
466 */
467static void cache_rbio(struct btrfs_raid_bio *rbio)
468{
469 struct btrfs_stripe_hash_table *table;
470 unsigned long flags;
471
472 if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags))
473 return;
474
475 table = rbio->fs_info->stripe_hash_table;
476
477 spin_lock_irqsave(&table->cache_lock, flags);
478 spin_lock(&rbio->bio_list_lock);
479
480 /* bump our ref if we were not in the list before */
481 if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags))
482 atomic_inc(&rbio->refs);
483
484 if (!list_empty(&rbio->stripe_cache)){
485 list_move(&rbio->stripe_cache, &table->stripe_cache);
486 } else {
487 list_add(&rbio->stripe_cache, &table->stripe_cache);
488 table->cache_size += 1;
489 }
490
491 spin_unlock(&rbio->bio_list_lock);
492
493 if (table->cache_size > RBIO_CACHE_SIZE) {
494 struct btrfs_raid_bio *found;
495
496 found = list_entry(table->stripe_cache.prev,
497 struct btrfs_raid_bio,
498 stripe_cache);
499
500 if (found != rbio)
501 __remove_rbio_from_cache(found);
502 }
503
504 spin_unlock_irqrestore(&table->cache_lock, flags);
505 return;
506}
507
508/*
David Woodhouse53b381b2013-01-29 18:40:14 -0500509 * helper function to run the xor_blocks api. It is only
510 * able to do MAX_XOR_BLOCKS at a time, so we need to
511 * loop through.
512 */
513static void run_xor(void **pages, int src_cnt, ssize_t len)
514{
515 int src_off = 0;
516 int xor_src_cnt = 0;
517 void *dest = pages[src_cnt];
518
519 while(src_cnt > 0) {
520 xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS);
521 xor_blocks(xor_src_cnt, len, dest, pages + src_off);
522
523 src_cnt -= xor_src_cnt;
524 src_off += xor_src_cnt;
525 }
526}
527
528/*
529 * returns true if the bio list inside this rbio
530 * covers an entire stripe (no rmw required).
531 * Must be called with the bio list lock held, or
532 * at a time when you know it is impossible to add
533 * new bios into the list
534 */
535static int __rbio_is_full(struct btrfs_raid_bio *rbio)
536{
537 unsigned long size = rbio->bio_list_bytes;
538 int ret = 1;
539
540 if (size != rbio->nr_data * rbio->stripe_len)
541 ret = 0;
542
543 BUG_ON(size > rbio->nr_data * rbio->stripe_len);
544 return ret;
545}
546
547static int rbio_is_full(struct btrfs_raid_bio *rbio)
548{
549 unsigned long flags;
550 int ret;
551
552 spin_lock_irqsave(&rbio->bio_list_lock, flags);
553 ret = __rbio_is_full(rbio);
554 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
555 return ret;
556}
557
558/*
559 * returns 1 if it is safe to merge two rbios together.
560 * The merging is safe if the two rbios correspond to
561 * the same stripe and if they are both going in the same
562 * direction (read vs write), and if neither one is
563 * locked for final IO
564 *
565 * The caller is responsible for locking such that
566 * rmw_locked is safe to test
567 */
568static int rbio_can_merge(struct btrfs_raid_bio *last,
569 struct btrfs_raid_bio *cur)
570{
571 if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) ||
572 test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags))
573 return 0;
574
Chris Mason4ae10b32013-01-31 14:42:09 -0500575 /*
576 * we can't merge with cached rbios, since the
577 * idea is that when we merge the destination
578 * rbio is going to run our IO for us. We can
579 * steal from cached rbio's though, other functions
580 * handle that.
581 */
582 if (test_bit(RBIO_CACHE_BIT, &last->flags) ||
583 test_bit(RBIO_CACHE_BIT, &cur->flags))
584 return 0;
585
Zhao Lei8e5cfb52015-01-20 15:11:33 +0800586 if (last->bbio->raid_map[0] !=
587 cur->bbio->raid_map[0])
David Woodhouse53b381b2013-01-29 18:40:14 -0500588 return 0;
589
Miao Xie5a6ac9e2014-11-06 17:20:58 +0800590 /* we can't merge with different operations */
591 if (last->operation != cur->operation)
David Woodhouse53b381b2013-01-29 18:40:14 -0500592 return 0;
Miao Xie5a6ac9e2014-11-06 17:20:58 +0800593 /*
594 * We've need read the full stripe from the drive.
595 * check and repair the parity and write the new results.
596 *
597 * We're not allowed to add any new bios to the
598 * bio list here, anyone else that wants to
599 * change this stripe needs to do their own rmw.
600 */
601 if (last->operation == BTRFS_RBIO_PARITY_SCRUB ||
602 cur->operation == BTRFS_RBIO_PARITY_SCRUB)
603 return 0;
David Woodhouse53b381b2013-01-29 18:40:14 -0500604
605 return 1;
606}
607
608/*
609 * helper to index into the pstripe
610 */
611static struct page *rbio_pstripe_page(struct btrfs_raid_bio *rbio, int index)
612{
613 index += (rbio->nr_data * rbio->stripe_len) >> PAGE_CACHE_SHIFT;
614 return rbio->stripe_pages[index];
615}
616
617/*
618 * helper to index into the qstripe, returns null
619 * if there is no qstripe
620 */
621static struct page *rbio_qstripe_page(struct btrfs_raid_bio *rbio, int index)
622{
Miao Xie2c8cdd62014-11-14 16:06:25 +0800623 if (rbio->nr_data + 1 == rbio->real_stripes)
David Woodhouse53b381b2013-01-29 18:40:14 -0500624 return NULL;
625
626 index += ((rbio->nr_data + 1) * rbio->stripe_len) >>
627 PAGE_CACHE_SHIFT;
628 return rbio->stripe_pages[index];
629}
630
631/*
632 * The first stripe in the table for a logical address
633 * has the lock. rbios are added in one of three ways:
634 *
635 * 1) Nobody has the stripe locked yet. The rbio is given
636 * the lock and 0 is returned. The caller must start the IO
637 * themselves.
638 *
639 * 2) Someone has the stripe locked, but we're able to merge
640 * with the lock owner. The rbio is freed and the IO will
641 * start automatically along with the existing rbio. 1 is returned.
642 *
643 * 3) Someone has the stripe locked, but we're not able to merge.
644 * The rbio is added to the lock owner's plug list, or merged into
645 * an rbio already on the plug list. When the lock owner unlocks,
646 * the next rbio on the list is run and the IO is started automatically.
647 * 1 is returned
648 *
649 * If we return 0, the caller still owns the rbio and must continue with
650 * IO submission. If we return 1, the caller must assume the rbio has
651 * already been freed.
652 */
653static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio)
654{
655 int bucket = rbio_bucket(rbio);
656 struct btrfs_stripe_hash *h = rbio->fs_info->stripe_hash_table->table + bucket;
657 struct btrfs_raid_bio *cur;
658 struct btrfs_raid_bio *pending;
659 unsigned long flags;
660 DEFINE_WAIT(wait);
661 struct btrfs_raid_bio *freeit = NULL;
Chris Mason4ae10b32013-01-31 14:42:09 -0500662 struct btrfs_raid_bio *cache_drop = NULL;
David Woodhouse53b381b2013-01-29 18:40:14 -0500663 int ret = 0;
664 int walk = 0;
665
666 spin_lock_irqsave(&h->lock, flags);
667 list_for_each_entry(cur, &h->hash_list, hash_list) {
668 walk++;
Zhao Lei8e5cfb52015-01-20 15:11:33 +0800669 if (cur->bbio->raid_map[0] == rbio->bbio->raid_map[0]) {
David Woodhouse53b381b2013-01-29 18:40:14 -0500670 spin_lock(&cur->bio_list_lock);
671
Chris Mason4ae10b32013-01-31 14:42:09 -0500672 /* can we steal this cached rbio's pages? */
673 if (bio_list_empty(&cur->bio_list) &&
674 list_empty(&cur->plug_list) &&
675 test_bit(RBIO_CACHE_BIT, &cur->flags) &&
676 !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) {
677 list_del_init(&cur->hash_list);
678 atomic_dec(&cur->refs);
679
680 steal_rbio(cur, rbio);
681 cache_drop = cur;
682 spin_unlock(&cur->bio_list_lock);
683
684 goto lockit;
685 }
686
David Woodhouse53b381b2013-01-29 18:40:14 -0500687 /* can we merge into the lock owner? */
688 if (rbio_can_merge(cur, rbio)) {
689 merge_rbio(cur, rbio);
690 spin_unlock(&cur->bio_list_lock);
691 freeit = rbio;
692 ret = 1;
693 goto out;
694 }
695
Chris Mason4ae10b32013-01-31 14:42:09 -0500696
David Woodhouse53b381b2013-01-29 18:40:14 -0500697 /*
698 * we couldn't merge with the running
699 * rbio, see if we can merge with the
700 * pending ones. We don't have to
701 * check for rmw_locked because there
702 * is no way they are inside finish_rmw
703 * right now
704 */
705 list_for_each_entry(pending, &cur->plug_list,
706 plug_list) {
707 if (rbio_can_merge(pending, rbio)) {
708 merge_rbio(pending, rbio);
709 spin_unlock(&cur->bio_list_lock);
710 freeit = rbio;
711 ret = 1;
712 goto out;
713 }
714 }
715
716 /* no merging, put us on the tail of the plug list,
717 * our rbio will be started with the currently
718 * running rbio unlocks
719 */
720 list_add_tail(&rbio->plug_list, &cur->plug_list);
721 spin_unlock(&cur->bio_list_lock);
722 ret = 1;
723 goto out;
724 }
725 }
Chris Mason4ae10b32013-01-31 14:42:09 -0500726lockit:
David Woodhouse53b381b2013-01-29 18:40:14 -0500727 atomic_inc(&rbio->refs);
728 list_add(&rbio->hash_list, &h->hash_list);
729out:
730 spin_unlock_irqrestore(&h->lock, flags);
Chris Mason4ae10b32013-01-31 14:42:09 -0500731 if (cache_drop)
732 remove_rbio_from_cache(cache_drop);
David Woodhouse53b381b2013-01-29 18:40:14 -0500733 if (freeit)
734 __free_raid_bio(freeit);
735 return ret;
736}
737
738/*
739 * called as rmw or parity rebuild is completed. If the plug list has more
740 * rbios waiting for this stripe, the next one on the list will be started
741 */
742static noinline void unlock_stripe(struct btrfs_raid_bio *rbio)
743{
744 int bucket;
745 struct btrfs_stripe_hash *h;
746 unsigned long flags;
Chris Mason4ae10b32013-01-31 14:42:09 -0500747 int keep_cache = 0;
David Woodhouse53b381b2013-01-29 18:40:14 -0500748
749 bucket = rbio_bucket(rbio);
750 h = rbio->fs_info->stripe_hash_table->table + bucket;
751
Chris Mason4ae10b32013-01-31 14:42:09 -0500752 if (list_empty(&rbio->plug_list))
753 cache_rbio(rbio);
754
David Woodhouse53b381b2013-01-29 18:40:14 -0500755 spin_lock_irqsave(&h->lock, flags);
756 spin_lock(&rbio->bio_list_lock);
757
758 if (!list_empty(&rbio->hash_list)) {
Chris Mason4ae10b32013-01-31 14:42:09 -0500759 /*
760 * if we're still cached and there is no other IO
761 * to perform, just leave this rbio here for others
762 * to steal from later
763 */
764 if (list_empty(&rbio->plug_list) &&
765 test_bit(RBIO_CACHE_BIT, &rbio->flags)) {
766 keep_cache = 1;
767 clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
768 BUG_ON(!bio_list_empty(&rbio->bio_list));
769 goto done;
770 }
David Woodhouse53b381b2013-01-29 18:40:14 -0500771
772 list_del_init(&rbio->hash_list);
773 atomic_dec(&rbio->refs);
774
775 /*
776 * we use the plug list to hold all the rbios
777 * waiting for the chance to lock this stripe.
778 * hand the lock over to one of them.
779 */
780 if (!list_empty(&rbio->plug_list)) {
781 struct btrfs_raid_bio *next;
782 struct list_head *head = rbio->plug_list.next;
783
784 next = list_entry(head, struct btrfs_raid_bio,
785 plug_list);
786
787 list_del_init(&rbio->plug_list);
788
789 list_add(&next->hash_list, &h->hash_list);
790 atomic_inc(&next->refs);
791 spin_unlock(&rbio->bio_list_lock);
792 spin_unlock_irqrestore(&h->lock, flags);
793
Miao Xie1b94b552014-11-06 16:14:21 +0800794 if (next->operation == BTRFS_RBIO_READ_REBUILD)
David Woodhouse53b381b2013-01-29 18:40:14 -0500795 async_read_rebuild(next);
Miao Xie5a6ac9e2014-11-06 17:20:58 +0800796 else if (next->operation == BTRFS_RBIO_WRITE) {
Chris Mason4ae10b32013-01-31 14:42:09 -0500797 steal_rbio(rbio, next);
David Woodhouse53b381b2013-01-29 18:40:14 -0500798 async_rmw_stripe(next);
Miao Xie5a6ac9e2014-11-06 17:20:58 +0800799 } else if (next->operation == BTRFS_RBIO_PARITY_SCRUB) {
800 steal_rbio(rbio, next);
801 async_scrub_parity(next);
Chris Mason4ae10b32013-01-31 14:42:09 -0500802 }
David Woodhouse53b381b2013-01-29 18:40:14 -0500803
804 goto done_nolock;
David Woodhouse53b381b2013-01-29 18:40:14 -0500805 } else if (waitqueue_active(&h->wait)) {
806 spin_unlock(&rbio->bio_list_lock);
807 spin_unlock_irqrestore(&h->lock, flags);
808 wake_up(&h->wait);
809 goto done_nolock;
810 }
811 }
Chris Mason4ae10b32013-01-31 14:42:09 -0500812done:
David Woodhouse53b381b2013-01-29 18:40:14 -0500813 spin_unlock(&rbio->bio_list_lock);
814 spin_unlock_irqrestore(&h->lock, flags);
815
816done_nolock:
Chris Mason4ae10b32013-01-31 14:42:09 -0500817 if (!keep_cache)
818 remove_rbio_from_cache(rbio);
David Woodhouse53b381b2013-01-29 18:40:14 -0500819}
820
821static void __free_raid_bio(struct btrfs_raid_bio *rbio)
822{
823 int i;
824
825 WARN_ON(atomic_read(&rbio->refs) < 0);
826 if (!atomic_dec_and_test(&rbio->refs))
827 return;
828
Chris Mason4ae10b32013-01-31 14:42:09 -0500829 WARN_ON(!list_empty(&rbio->stripe_cache));
David Woodhouse53b381b2013-01-29 18:40:14 -0500830 WARN_ON(!list_empty(&rbio->hash_list));
831 WARN_ON(!bio_list_empty(&rbio->bio_list));
832
833 for (i = 0; i < rbio->nr_pages; i++) {
834 if (rbio->stripe_pages[i]) {
835 __free_page(rbio->stripe_pages[i]);
836 rbio->stripe_pages[i] = NULL;
837 }
838 }
Miao Xieaf8e2d12014-10-23 14:42:50 +0800839
Zhao Lei6e9606d2015-01-20 15:11:34 +0800840 btrfs_put_bbio(rbio->bbio);
David Woodhouse53b381b2013-01-29 18:40:14 -0500841 kfree(rbio);
842}
843
844static void free_raid_bio(struct btrfs_raid_bio *rbio)
845{
846 unlock_stripe(rbio);
847 __free_raid_bio(rbio);
848}
849
850/*
851 * this frees the rbio and runs through all the bios in the
852 * bio_list and calls end_io on them
853 */
854static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, int err, int uptodate)
855{
856 struct bio *cur = bio_list_get(&rbio->bio_list);
857 struct bio *next;
Miao Xie42452152014-11-25 16:39:28 +0800858
859 if (rbio->generic_bio_cnt)
860 btrfs_bio_counter_sub(rbio->fs_info, rbio->generic_bio_cnt);
861
David Woodhouse53b381b2013-01-29 18:40:14 -0500862 free_raid_bio(rbio);
863
864 while (cur) {
865 next = cur->bi_next;
866 cur->bi_next = NULL;
867 if (uptodate)
868 set_bit(BIO_UPTODATE, &cur->bi_flags);
869 bio_endio(cur, err);
870 cur = next;
871 }
872}
873
874/*
875 * end io function used by finish_rmw. When we finally
876 * get here, we've written a full stripe
877 */
878static void raid_write_end_io(struct bio *bio, int err)
879{
880 struct btrfs_raid_bio *rbio = bio->bi_private;
881
882 if (err)
883 fail_bio_stripe(rbio, bio);
884
885 bio_put(bio);
886
Miao Xieb89e1b02014-10-15 11:18:44 +0800887 if (!atomic_dec_and_test(&rbio->stripes_pending))
David Woodhouse53b381b2013-01-29 18:40:14 -0500888 return;
889
890 err = 0;
891
892 /* OK, we have read all the stripes we need to. */
Miao Xieb89e1b02014-10-15 11:18:44 +0800893 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
David Woodhouse53b381b2013-01-29 18:40:14 -0500894 err = -EIO;
895
896 rbio_orig_end_io(rbio, err, 0);
897 return;
898}
899
900/*
901 * the read/modify/write code wants to use the original bio for
902 * any pages it included, and then use the rbio for everything
903 * else. This function decides if a given index (stripe number)
904 * and page number in that stripe fall inside the original bio
905 * or the rbio.
906 *
907 * if you set bio_list_only, you'll get a NULL back for any ranges
908 * that are outside the bio_list
909 *
910 * This doesn't take any refs on anything, you get a bare page pointer
911 * and the caller must bump refs as required.
912 *
913 * You must call index_rbio_pages once before you can trust
914 * the answers from this function.
915 */
916static struct page *page_in_rbio(struct btrfs_raid_bio *rbio,
917 int index, int pagenr, int bio_list_only)
918{
919 int chunk_page;
920 struct page *p = NULL;
921
922 chunk_page = index * (rbio->stripe_len >> PAGE_SHIFT) + pagenr;
923
924 spin_lock_irq(&rbio->bio_list_lock);
925 p = rbio->bio_pages[chunk_page];
926 spin_unlock_irq(&rbio->bio_list_lock);
927
928 if (p || bio_list_only)
929 return p;
930
931 return rbio->stripe_pages[chunk_page];
932}
933
934/*
935 * number of pages we need for the entire stripe across all the
936 * drives
937 */
938static unsigned long rbio_nr_pages(unsigned long stripe_len, int nr_stripes)
939{
940 unsigned long nr = stripe_len * nr_stripes;
David Sterbaed6078f2014-06-05 01:59:57 +0200941 return DIV_ROUND_UP(nr, PAGE_CACHE_SIZE);
David Woodhouse53b381b2013-01-29 18:40:14 -0500942}
943
944/*
945 * allocation and initial setup for the btrfs_raid_bio. Not
946 * this does not allocate any pages for rbio->pages.
947 */
948static struct btrfs_raid_bio *alloc_rbio(struct btrfs_root *root,
Zhao Lei8e5cfb52015-01-20 15:11:33 +0800949 struct btrfs_bio *bbio, u64 stripe_len)
David Woodhouse53b381b2013-01-29 18:40:14 -0500950{
951 struct btrfs_raid_bio *rbio;
952 int nr_data = 0;
Miao Xie2c8cdd62014-11-14 16:06:25 +0800953 int real_stripes = bbio->num_stripes - bbio->num_tgtdevs;
954 int num_pages = rbio_nr_pages(stripe_len, real_stripes);
Miao Xie5a6ac9e2014-11-06 17:20:58 +0800955 int stripe_npages = DIV_ROUND_UP(stripe_len, PAGE_SIZE);
David Woodhouse53b381b2013-01-29 18:40:14 -0500956 void *p;
957
Miao Xie5a6ac9e2014-11-06 17:20:58 +0800958 rbio = kzalloc(sizeof(*rbio) + num_pages * sizeof(struct page *) * 2 +
959 DIV_ROUND_UP(stripe_npages, BITS_PER_LONG / 8),
David Woodhouse53b381b2013-01-29 18:40:14 -0500960 GFP_NOFS);
Miao Xieaf8e2d12014-10-23 14:42:50 +0800961 if (!rbio)
David Woodhouse53b381b2013-01-29 18:40:14 -0500962 return ERR_PTR(-ENOMEM);
David Woodhouse53b381b2013-01-29 18:40:14 -0500963
964 bio_list_init(&rbio->bio_list);
965 INIT_LIST_HEAD(&rbio->plug_list);
966 spin_lock_init(&rbio->bio_list_lock);
Chris Mason4ae10b32013-01-31 14:42:09 -0500967 INIT_LIST_HEAD(&rbio->stripe_cache);
David Woodhouse53b381b2013-01-29 18:40:14 -0500968 INIT_LIST_HEAD(&rbio->hash_list);
969 rbio->bbio = bbio;
David Woodhouse53b381b2013-01-29 18:40:14 -0500970 rbio->fs_info = root->fs_info;
971 rbio->stripe_len = stripe_len;
972 rbio->nr_pages = num_pages;
Miao Xie2c8cdd62014-11-14 16:06:25 +0800973 rbio->real_stripes = real_stripes;
Miao Xie5a6ac9e2014-11-06 17:20:58 +0800974 rbio->stripe_npages = stripe_npages;
David Woodhouse53b381b2013-01-29 18:40:14 -0500975 rbio->faila = -1;
976 rbio->failb = -1;
977 atomic_set(&rbio->refs, 1);
Miao Xieb89e1b02014-10-15 11:18:44 +0800978 atomic_set(&rbio->error, 0);
979 atomic_set(&rbio->stripes_pending, 0);
David Woodhouse53b381b2013-01-29 18:40:14 -0500980
981 /*
982 * the stripe_pages and bio_pages array point to the extra
983 * memory we allocated past the end of the rbio
984 */
985 p = rbio + 1;
986 rbio->stripe_pages = p;
987 rbio->bio_pages = p + sizeof(struct page *) * num_pages;
Miao Xie5a6ac9e2014-11-06 17:20:58 +0800988 rbio->dbitmap = p + sizeof(struct page *) * num_pages * 2;
David Woodhouse53b381b2013-01-29 18:40:14 -0500989
Zhao Lei10f11902015-01-20 15:11:43 +0800990 if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID5)
991 nr_data = real_stripes - 1;
992 else if (bbio->map_type & BTRFS_BLOCK_GROUP_RAID6)
Miao Xie2c8cdd62014-11-14 16:06:25 +0800993 nr_data = real_stripes - 2;
David Woodhouse53b381b2013-01-29 18:40:14 -0500994 else
Zhao Lei10f11902015-01-20 15:11:43 +0800995 BUG();
David Woodhouse53b381b2013-01-29 18:40:14 -0500996
997 rbio->nr_data = nr_data;
998 return rbio;
999}
1000
1001/* allocate pages for all the stripes in the bio, including parity */
1002static int alloc_rbio_pages(struct btrfs_raid_bio *rbio)
1003{
1004 int i;
1005 struct page *page;
1006
1007 for (i = 0; i < rbio->nr_pages; i++) {
1008 if (rbio->stripe_pages[i])
1009 continue;
1010 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1011 if (!page)
1012 return -ENOMEM;
1013 rbio->stripe_pages[i] = page;
1014 ClearPageUptodate(page);
1015 }
1016 return 0;
1017}
1018
1019/* allocate pages for just the p/q stripes */
1020static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio)
1021{
1022 int i;
1023 struct page *page;
1024
1025 i = (rbio->nr_data * rbio->stripe_len) >> PAGE_CACHE_SHIFT;
1026
1027 for (; i < rbio->nr_pages; i++) {
1028 if (rbio->stripe_pages[i])
1029 continue;
1030 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
1031 if (!page)
1032 return -ENOMEM;
1033 rbio->stripe_pages[i] = page;
1034 }
1035 return 0;
1036}
1037
1038/*
1039 * add a single page from a specific stripe into our list of bios for IO
1040 * this will try to merge into existing bios if possible, and returns
1041 * zero if all went well.
1042 */
Eric Sandeen48a3b632013-04-25 20:41:01 +00001043static int rbio_add_io_page(struct btrfs_raid_bio *rbio,
1044 struct bio_list *bio_list,
1045 struct page *page,
1046 int stripe_nr,
1047 unsigned long page_index,
1048 unsigned long bio_max_len)
David Woodhouse53b381b2013-01-29 18:40:14 -05001049{
1050 struct bio *last = bio_list->tail;
1051 u64 last_end = 0;
1052 int ret;
1053 struct bio *bio;
1054 struct btrfs_bio_stripe *stripe;
1055 u64 disk_start;
1056
1057 stripe = &rbio->bbio->stripes[stripe_nr];
1058 disk_start = stripe->physical + (page_index << PAGE_CACHE_SHIFT);
1059
1060 /* if the device is missing, just fail this stripe */
1061 if (!stripe->dev->bdev)
1062 return fail_rbio_index(rbio, stripe_nr);
1063
1064 /* see if we can add this page onto our existing bio */
1065 if (last) {
Kent Overstreet4f024f32013-10-11 15:44:27 -07001066 last_end = (u64)last->bi_iter.bi_sector << 9;
1067 last_end += last->bi_iter.bi_size;
David Woodhouse53b381b2013-01-29 18:40:14 -05001068
1069 /*
1070 * we can't merge these if they are from different
1071 * devices or if they are not contiguous
1072 */
1073 if (last_end == disk_start && stripe->dev->bdev &&
1074 test_bit(BIO_UPTODATE, &last->bi_flags) &&
1075 last->bi_bdev == stripe->dev->bdev) {
1076 ret = bio_add_page(last, page, PAGE_CACHE_SIZE, 0);
1077 if (ret == PAGE_CACHE_SIZE)
1078 return 0;
1079 }
1080 }
1081
1082 /* put a new bio on the list */
Chris Mason9be33952013-05-17 18:30:14 -04001083 bio = btrfs_io_bio_alloc(GFP_NOFS, bio_max_len >> PAGE_SHIFT?:1);
David Woodhouse53b381b2013-01-29 18:40:14 -05001084 if (!bio)
1085 return -ENOMEM;
1086
Kent Overstreet4f024f32013-10-11 15:44:27 -07001087 bio->bi_iter.bi_size = 0;
David Woodhouse53b381b2013-01-29 18:40:14 -05001088 bio->bi_bdev = stripe->dev->bdev;
Kent Overstreet4f024f32013-10-11 15:44:27 -07001089 bio->bi_iter.bi_sector = disk_start >> 9;
David Woodhouse53b381b2013-01-29 18:40:14 -05001090 set_bit(BIO_UPTODATE, &bio->bi_flags);
1091
1092 bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
1093 bio_list_add(bio_list, bio);
1094 return 0;
1095}
1096
1097/*
1098 * while we're doing the read/modify/write cycle, we could
1099 * have errors in reading pages off the disk. This checks
1100 * for errors and if we're not able to read the page it'll
1101 * trigger parity reconstruction. The rmw will be finished
1102 * after we've reconstructed the failed stripes
1103 */
1104static void validate_rbio_for_rmw(struct btrfs_raid_bio *rbio)
1105{
1106 if (rbio->faila >= 0 || rbio->failb >= 0) {
Miao Xie2c8cdd62014-11-14 16:06:25 +08001107 BUG_ON(rbio->faila == rbio->real_stripes - 1);
David Woodhouse53b381b2013-01-29 18:40:14 -05001108 __raid56_parity_recover(rbio);
1109 } else {
1110 finish_rmw(rbio);
1111 }
1112}
1113
1114/*
1115 * these are just the pages from the rbio array, not from anything
1116 * the FS sent down to us
1117 */
1118static struct page *rbio_stripe_page(struct btrfs_raid_bio *rbio, int stripe, int page)
1119{
1120 int index;
1121 index = stripe * (rbio->stripe_len >> PAGE_CACHE_SHIFT);
1122 index += page;
1123 return rbio->stripe_pages[index];
1124}
1125
1126/*
1127 * helper function to walk our bio list and populate the bio_pages array with
1128 * the result. This seems expensive, but it is faster than constantly
1129 * searching through the bio list as we setup the IO in finish_rmw or stripe
1130 * reconstruction.
1131 *
1132 * This must be called before you trust the answers from page_in_rbio
1133 */
1134static void index_rbio_pages(struct btrfs_raid_bio *rbio)
1135{
1136 struct bio *bio;
1137 u64 start;
1138 unsigned long stripe_offset;
1139 unsigned long page_index;
1140 struct page *p;
1141 int i;
1142
1143 spin_lock_irq(&rbio->bio_list_lock);
1144 bio_list_for_each(bio, &rbio->bio_list) {
Kent Overstreet4f024f32013-10-11 15:44:27 -07001145 start = (u64)bio->bi_iter.bi_sector << 9;
Zhao Lei8e5cfb52015-01-20 15:11:33 +08001146 stripe_offset = start - rbio->bbio->raid_map[0];
David Woodhouse53b381b2013-01-29 18:40:14 -05001147 page_index = stripe_offset >> PAGE_CACHE_SHIFT;
1148
1149 for (i = 0; i < bio->bi_vcnt; i++) {
1150 p = bio->bi_io_vec[i].bv_page;
1151 rbio->bio_pages[page_index + i] = p;
1152 }
1153 }
1154 spin_unlock_irq(&rbio->bio_list_lock);
1155}
1156
1157/*
1158 * this is called from one of two situations. We either
1159 * have a full stripe from the higher layers, or we've read all
1160 * the missing bits off disk.
1161 *
1162 * This will calculate the parity and then send down any
1163 * changed blocks.
1164 */
1165static noinline void finish_rmw(struct btrfs_raid_bio *rbio)
1166{
1167 struct btrfs_bio *bbio = rbio->bbio;
Miao Xie2c8cdd62014-11-14 16:06:25 +08001168 void *pointers[rbio->real_stripes];
David Woodhouse53b381b2013-01-29 18:40:14 -05001169 int stripe_len = rbio->stripe_len;
1170 int nr_data = rbio->nr_data;
1171 int stripe;
1172 int pagenr;
1173 int p_stripe = -1;
1174 int q_stripe = -1;
1175 struct bio_list bio_list;
1176 struct bio *bio;
1177 int pages_per_stripe = stripe_len >> PAGE_CACHE_SHIFT;
1178 int ret;
1179
1180 bio_list_init(&bio_list);
1181
Miao Xie2c8cdd62014-11-14 16:06:25 +08001182 if (rbio->real_stripes - rbio->nr_data == 1) {
1183 p_stripe = rbio->real_stripes - 1;
1184 } else if (rbio->real_stripes - rbio->nr_data == 2) {
1185 p_stripe = rbio->real_stripes - 2;
1186 q_stripe = rbio->real_stripes - 1;
David Woodhouse53b381b2013-01-29 18:40:14 -05001187 } else {
1188 BUG();
1189 }
1190
1191 /* at this point we either have a full stripe,
1192 * or we've read the full stripe from the drive.
1193 * recalculate the parity and write the new results.
1194 *
1195 * We're not allowed to add any new bios to the
1196 * bio list here, anyone else that wants to
1197 * change this stripe needs to do their own rmw.
1198 */
1199 spin_lock_irq(&rbio->bio_list_lock);
1200 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1201 spin_unlock_irq(&rbio->bio_list_lock);
1202
Miao Xieb89e1b02014-10-15 11:18:44 +08001203 atomic_set(&rbio->error, 0);
David Woodhouse53b381b2013-01-29 18:40:14 -05001204
1205 /*
1206 * now that we've set rmw_locked, run through the
1207 * bio list one last time and map the page pointers
Chris Mason4ae10b32013-01-31 14:42:09 -05001208 *
1209 * We don't cache full rbios because we're assuming
1210 * the higher layers are unlikely to use this area of
1211 * the disk again soon. If they do use it again,
1212 * hopefully they will send another full bio.
David Woodhouse53b381b2013-01-29 18:40:14 -05001213 */
1214 index_rbio_pages(rbio);
Chris Mason4ae10b32013-01-31 14:42:09 -05001215 if (!rbio_is_full(rbio))
1216 cache_rbio_pages(rbio);
1217 else
1218 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
David Woodhouse53b381b2013-01-29 18:40:14 -05001219
1220 for (pagenr = 0; pagenr < pages_per_stripe; pagenr++) {
1221 struct page *p;
1222 /* first collect one page from each data stripe */
1223 for (stripe = 0; stripe < nr_data; stripe++) {
1224 p = page_in_rbio(rbio, stripe, pagenr, 0);
1225 pointers[stripe] = kmap(p);
1226 }
1227
1228 /* then add the parity stripe */
1229 p = rbio_pstripe_page(rbio, pagenr);
1230 SetPageUptodate(p);
1231 pointers[stripe++] = kmap(p);
1232
1233 if (q_stripe != -1) {
1234
1235 /*
1236 * raid6, add the qstripe and call the
1237 * library function to fill in our p/q
1238 */
1239 p = rbio_qstripe_page(rbio, pagenr);
1240 SetPageUptodate(p);
1241 pointers[stripe++] = kmap(p);
1242
Miao Xie2c8cdd62014-11-14 16:06:25 +08001243 raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
David Woodhouse53b381b2013-01-29 18:40:14 -05001244 pointers);
1245 } else {
1246 /* raid5 */
1247 memcpy(pointers[nr_data], pointers[0], PAGE_SIZE);
1248 run_xor(pointers + 1, nr_data - 1, PAGE_CACHE_SIZE);
1249 }
1250
1251
Miao Xie2c8cdd62014-11-14 16:06:25 +08001252 for (stripe = 0; stripe < rbio->real_stripes; stripe++)
David Woodhouse53b381b2013-01-29 18:40:14 -05001253 kunmap(page_in_rbio(rbio, stripe, pagenr, 0));
1254 }
1255
1256 /*
1257 * time to start writing. Make bios for everything from the
1258 * higher layers (the bio_list in our rbio) and our p/q. Ignore
1259 * everything else.
1260 */
Miao Xie2c8cdd62014-11-14 16:06:25 +08001261 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
David Woodhouse53b381b2013-01-29 18:40:14 -05001262 for (pagenr = 0; pagenr < pages_per_stripe; pagenr++) {
1263 struct page *page;
1264 if (stripe < rbio->nr_data) {
1265 page = page_in_rbio(rbio, stripe, pagenr, 1);
1266 if (!page)
1267 continue;
1268 } else {
1269 page = rbio_stripe_page(rbio, stripe, pagenr);
1270 }
1271
1272 ret = rbio_add_io_page(rbio, &bio_list,
1273 page, stripe, pagenr, rbio->stripe_len);
1274 if (ret)
1275 goto cleanup;
1276 }
1277 }
1278
Miao Xie2c8cdd62014-11-14 16:06:25 +08001279 if (likely(!bbio->num_tgtdevs))
1280 goto write_data;
1281
1282 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
1283 if (!bbio->tgtdev_map[stripe])
1284 continue;
1285
1286 for (pagenr = 0; pagenr < pages_per_stripe; pagenr++) {
1287 struct page *page;
1288 if (stripe < rbio->nr_data) {
1289 page = page_in_rbio(rbio, stripe, pagenr, 1);
1290 if (!page)
1291 continue;
1292 } else {
1293 page = rbio_stripe_page(rbio, stripe, pagenr);
1294 }
1295
1296 ret = rbio_add_io_page(rbio, &bio_list, page,
1297 rbio->bbio->tgtdev_map[stripe],
1298 pagenr, rbio->stripe_len);
1299 if (ret)
1300 goto cleanup;
1301 }
1302 }
1303
1304write_data:
Miao Xieb89e1b02014-10-15 11:18:44 +08001305 atomic_set(&rbio->stripes_pending, bio_list_size(&bio_list));
1306 BUG_ON(atomic_read(&rbio->stripes_pending) == 0);
David Woodhouse53b381b2013-01-29 18:40:14 -05001307
1308 while (1) {
1309 bio = bio_list_pop(&bio_list);
1310 if (!bio)
1311 break;
1312
1313 bio->bi_private = rbio;
1314 bio->bi_end_io = raid_write_end_io;
1315 BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
1316 submit_bio(WRITE, bio);
1317 }
1318 return;
1319
1320cleanup:
1321 rbio_orig_end_io(rbio, -EIO, 0);
1322}
1323
1324/*
1325 * helper to find the stripe number for a given bio. Used to figure out which
1326 * stripe has failed. This expects the bio to correspond to a physical disk,
1327 * so it looks up based on physical sector numbers.
1328 */
1329static int find_bio_stripe(struct btrfs_raid_bio *rbio,
1330 struct bio *bio)
1331{
Kent Overstreet4f024f32013-10-11 15:44:27 -07001332 u64 physical = bio->bi_iter.bi_sector;
David Woodhouse53b381b2013-01-29 18:40:14 -05001333 u64 stripe_start;
1334 int i;
1335 struct btrfs_bio_stripe *stripe;
1336
1337 physical <<= 9;
1338
1339 for (i = 0; i < rbio->bbio->num_stripes; i++) {
1340 stripe = &rbio->bbio->stripes[i];
1341 stripe_start = stripe->physical;
1342 if (physical >= stripe_start &&
Miao Xie2c8cdd62014-11-14 16:06:25 +08001343 physical < stripe_start + rbio->stripe_len &&
1344 bio->bi_bdev == stripe->dev->bdev) {
David Woodhouse53b381b2013-01-29 18:40:14 -05001345 return i;
1346 }
1347 }
1348 return -1;
1349}
1350
1351/*
1352 * helper to find the stripe number for a given
1353 * bio (before mapping). Used to figure out which stripe has
1354 * failed. This looks up based on logical block numbers.
1355 */
1356static int find_logical_bio_stripe(struct btrfs_raid_bio *rbio,
1357 struct bio *bio)
1358{
Kent Overstreet4f024f32013-10-11 15:44:27 -07001359 u64 logical = bio->bi_iter.bi_sector;
David Woodhouse53b381b2013-01-29 18:40:14 -05001360 u64 stripe_start;
1361 int i;
1362
1363 logical <<= 9;
1364
1365 for (i = 0; i < rbio->nr_data; i++) {
Zhao Lei8e5cfb52015-01-20 15:11:33 +08001366 stripe_start = rbio->bbio->raid_map[i];
David Woodhouse53b381b2013-01-29 18:40:14 -05001367 if (logical >= stripe_start &&
1368 logical < stripe_start + rbio->stripe_len) {
1369 return i;
1370 }
1371 }
1372 return -1;
1373}
1374
1375/*
1376 * returns -EIO if we had too many failures
1377 */
1378static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed)
1379{
1380 unsigned long flags;
1381 int ret = 0;
1382
1383 spin_lock_irqsave(&rbio->bio_list_lock, flags);
1384
1385 /* we already know this stripe is bad, move on */
1386 if (rbio->faila == failed || rbio->failb == failed)
1387 goto out;
1388
1389 if (rbio->faila == -1) {
1390 /* first failure on this rbio */
1391 rbio->faila = failed;
Miao Xieb89e1b02014-10-15 11:18:44 +08001392 atomic_inc(&rbio->error);
David Woodhouse53b381b2013-01-29 18:40:14 -05001393 } else if (rbio->failb == -1) {
1394 /* second failure on this rbio */
1395 rbio->failb = failed;
Miao Xieb89e1b02014-10-15 11:18:44 +08001396 atomic_inc(&rbio->error);
David Woodhouse53b381b2013-01-29 18:40:14 -05001397 } else {
1398 ret = -EIO;
1399 }
1400out:
1401 spin_unlock_irqrestore(&rbio->bio_list_lock, flags);
1402
1403 return ret;
1404}
1405
1406/*
1407 * helper to fail a stripe based on a physical disk
1408 * bio.
1409 */
1410static int fail_bio_stripe(struct btrfs_raid_bio *rbio,
1411 struct bio *bio)
1412{
1413 int failed = find_bio_stripe(rbio, bio);
1414
1415 if (failed < 0)
1416 return -EIO;
1417
1418 return fail_rbio_index(rbio, failed);
1419}
1420
1421/*
1422 * this sets each page in the bio uptodate. It should only be used on private
1423 * rbio pages, nothing that comes in from the higher layers
1424 */
1425static void set_bio_pages_uptodate(struct bio *bio)
1426{
1427 int i;
1428 struct page *p;
1429
1430 for (i = 0; i < bio->bi_vcnt; i++) {
1431 p = bio->bi_io_vec[i].bv_page;
1432 SetPageUptodate(p);
1433 }
1434}
1435
1436/*
1437 * end io for the read phase of the rmw cycle. All the bios here are physical
1438 * stripe bios we've read from the disk so we can recalculate the parity of the
1439 * stripe.
1440 *
1441 * This will usually kick off finish_rmw once all the bios are read in, but it
1442 * may trigger parity reconstruction if we had any errors along the way
1443 */
1444static void raid_rmw_end_io(struct bio *bio, int err)
1445{
1446 struct btrfs_raid_bio *rbio = bio->bi_private;
1447
1448 if (err)
1449 fail_bio_stripe(rbio, bio);
1450 else
1451 set_bio_pages_uptodate(bio);
1452
1453 bio_put(bio);
1454
Miao Xieb89e1b02014-10-15 11:18:44 +08001455 if (!atomic_dec_and_test(&rbio->stripes_pending))
David Woodhouse53b381b2013-01-29 18:40:14 -05001456 return;
1457
1458 err = 0;
Miao Xieb89e1b02014-10-15 11:18:44 +08001459 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
David Woodhouse53b381b2013-01-29 18:40:14 -05001460 goto cleanup;
1461
1462 /*
1463 * this will normally call finish_rmw to start our write
1464 * but if there are any failed stripes we'll reconstruct
1465 * from parity first
1466 */
1467 validate_rbio_for_rmw(rbio);
1468 return;
1469
1470cleanup:
1471
1472 rbio_orig_end_io(rbio, -EIO, 0);
1473}
1474
1475static void async_rmw_stripe(struct btrfs_raid_bio *rbio)
1476{
Liu Bo9e0af232014-08-15 23:36:53 +08001477 btrfs_init_work(&rbio->work, btrfs_rmw_helper,
1478 rmw_work, NULL, NULL);
David Woodhouse53b381b2013-01-29 18:40:14 -05001479
Qu Wenruod05a33a2014-02-28 10:46:11 +08001480 btrfs_queue_work(rbio->fs_info->rmw_workers,
1481 &rbio->work);
David Woodhouse53b381b2013-01-29 18:40:14 -05001482}
1483
1484static void async_read_rebuild(struct btrfs_raid_bio *rbio)
1485{
Liu Bo9e0af232014-08-15 23:36:53 +08001486 btrfs_init_work(&rbio->work, btrfs_rmw_helper,
1487 read_rebuild_work, NULL, NULL);
David Woodhouse53b381b2013-01-29 18:40:14 -05001488
Qu Wenruod05a33a2014-02-28 10:46:11 +08001489 btrfs_queue_work(rbio->fs_info->rmw_workers,
1490 &rbio->work);
David Woodhouse53b381b2013-01-29 18:40:14 -05001491}
1492
1493/*
1494 * the stripe must be locked by the caller. It will
1495 * unlock after all the writes are done
1496 */
1497static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio)
1498{
1499 int bios_to_read = 0;
David Woodhouse53b381b2013-01-29 18:40:14 -05001500 struct bio_list bio_list;
1501 int ret;
David Sterbaed6078f2014-06-05 01:59:57 +02001502 int nr_pages = DIV_ROUND_UP(rbio->stripe_len, PAGE_CACHE_SIZE);
David Woodhouse53b381b2013-01-29 18:40:14 -05001503 int pagenr;
1504 int stripe;
1505 struct bio *bio;
1506
1507 bio_list_init(&bio_list);
1508
1509 ret = alloc_rbio_pages(rbio);
1510 if (ret)
1511 goto cleanup;
1512
1513 index_rbio_pages(rbio);
1514
Miao Xieb89e1b02014-10-15 11:18:44 +08001515 atomic_set(&rbio->error, 0);
David Woodhouse53b381b2013-01-29 18:40:14 -05001516 /*
1517 * build a list of bios to read all the missing parts of this
1518 * stripe
1519 */
1520 for (stripe = 0; stripe < rbio->nr_data; stripe++) {
1521 for (pagenr = 0; pagenr < nr_pages; pagenr++) {
1522 struct page *page;
1523 /*
1524 * we want to find all the pages missing from
1525 * the rbio and read them from the disk. If
1526 * page_in_rbio finds a page in the bio list
1527 * we don't need to read it off the stripe.
1528 */
1529 page = page_in_rbio(rbio, stripe, pagenr, 1);
1530 if (page)
1531 continue;
1532
1533 page = rbio_stripe_page(rbio, stripe, pagenr);
Chris Mason4ae10b32013-01-31 14:42:09 -05001534 /*
1535 * the bio cache may have handed us an uptodate
1536 * page. If so, be happy and use it
1537 */
1538 if (PageUptodate(page))
1539 continue;
1540
David Woodhouse53b381b2013-01-29 18:40:14 -05001541 ret = rbio_add_io_page(rbio, &bio_list, page,
1542 stripe, pagenr, rbio->stripe_len);
1543 if (ret)
1544 goto cleanup;
1545 }
1546 }
1547
1548 bios_to_read = bio_list_size(&bio_list);
1549 if (!bios_to_read) {
1550 /*
1551 * this can happen if others have merged with
1552 * us, it means there is nothing left to read.
1553 * But if there are missing devices it may not be
1554 * safe to do the full stripe write yet.
1555 */
1556 goto finish;
1557 }
1558
1559 /*
1560 * the bbio may be freed once we submit the last bio. Make sure
1561 * not to touch it after that
1562 */
Miao Xieb89e1b02014-10-15 11:18:44 +08001563 atomic_set(&rbio->stripes_pending, bios_to_read);
David Woodhouse53b381b2013-01-29 18:40:14 -05001564 while (1) {
1565 bio = bio_list_pop(&bio_list);
1566 if (!bio)
1567 break;
1568
1569 bio->bi_private = rbio;
1570 bio->bi_end_io = raid_rmw_end_io;
1571
1572 btrfs_bio_wq_end_io(rbio->fs_info, bio,
1573 BTRFS_WQ_ENDIO_RAID56);
1574
1575 BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
1576 submit_bio(READ, bio);
1577 }
1578 /* the actual write will happen once the reads are done */
1579 return 0;
1580
1581cleanup:
1582 rbio_orig_end_io(rbio, -EIO, 0);
1583 return -EIO;
1584
1585finish:
1586 validate_rbio_for_rmw(rbio);
1587 return 0;
1588}
1589
1590/*
1591 * if the upper layers pass in a full stripe, we thank them by only allocating
1592 * enough pages to hold the parity, and sending it all down quickly.
1593 */
1594static int full_stripe_write(struct btrfs_raid_bio *rbio)
1595{
1596 int ret;
1597
1598 ret = alloc_rbio_parity_pages(rbio);
Miao Xie3cd846d2013-07-22 16:36:57 +08001599 if (ret) {
1600 __free_raid_bio(rbio);
David Woodhouse53b381b2013-01-29 18:40:14 -05001601 return ret;
Miao Xie3cd846d2013-07-22 16:36:57 +08001602 }
David Woodhouse53b381b2013-01-29 18:40:14 -05001603
1604 ret = lock_stripe_add(rbio);
1605 if (ret == 0)
1606 finish_rmw(rbio);
1607 return 0;
1608}
1609
1610/*
1611 * partial stripe writes get handed over to async helpers.
1612 * We're really hoping to merge a few more writes into this
1613 * rbio before calculating new parity
1614 */
1615static int partial_stripe_write(struct btrfs_raid_bio *rbio)
1616{
1617 int ret;
1618
1619 ret = lock_stripe_add(rbio);
1620 if (ret == 0)
1621 async_rmw_stripe(rbio);
1622 return 0;
1623}
1624
1625/*
1626 * sometimes while we were reading from the drive to
1627 * recalculate parity, enough new bios come into create
1628 * a full stripe. So we do a check here to see if we can
1629 * go directly to finish_rmw
1630 */
1631static int __raid56_parity_write(struct btrfs_raid_bio *rbio)
1632{
1633 /* head off into rmw land if we don't have a full stripe */
1634 if (!rbio_is_full(rbio))
1635 return partial_stripe_write(rbio);
1636 return full_stripe_write(rbio);
1637}
1638
1639/*
Chris Mason6ac0f482013-01-31 14:42:28 -05001640 * We use plugging call backs to collect full stripes.
1641 * Any time we get a partial stripe write while plugged
1642 * we collect it into a list. When the unplug comes down,
1643 * we sort the list by logical block number and merge
1644 * everything we can into the same rbios
1645 */
1646struct btrfs_plug_cb {
1647 struct blk_plug_cb cb;
1648 struct btrfs_fs_info *info;
1649 struct list_head rbio_list;
1650 struct btrfs_work work;
1651};
1652
1653/*
1654 * rbios on the plug list are sorted for easier merging.
1655 */
1656static int plug_cmp(void *priv, struct list_head *a, struct list_head *b)
1657{
1658 struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio,
1659 plug_list);
1660 struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio,
1661 plug_list);
Kent Overstreet4f024f32013-10-11 15:44:27 -07001662 u64 a_sector = ra->bio_list.head->bi_iter.bi_sector;
1663 u64 b_sector = rb->bio_list.head->bi_iter.bi_sector;
Chris Mason6ac0f482013-01-31 14:42:28 -05001664
1665 if (a_sector < b_sector)
1666 return -1;
1667 if (a_sector > b_sector)
1668 return 1;
1669 return 0;
1670}
1671
1672static void run_plug(struct btrfs_plug_cb *plug)
1673{
1674 struct btrfs_raid_bio *cur;
1675 struct btrfs_raid_bio *last = NULL;
1676
1677 /*
1678 * sort our plug list then try to merge
1679 * everything we can in hopes of creating full
1680 * stripes.
1681 */
1682 list_sort(NULL, &plug->rbio_list, plug_cmp);
1683 while (!list_empty(&plug->rbio_list)) {
1684 cur = list_entry(plug->rbio_list.next,
1685 struct btrfs_raid_bio, plug_list);
1686 list_del_init(&cur->plug_list);
1687
1688 if (rbio_is_full(cur)) {
1689 /* we have a full stripe, send it down */
1690 full_stripe_write(cur);
1691 continue;
1692 }
1693 if (last) {
1694 if (rbio_can_merge(last, cur)) {
1695 merge_rbio(last, cur);
1696 __free_raid_bio(cur);
1697 continue;
1698
1699 }
1700 __raid56_parity_write(last);
1701 }
1702 last = cur;
1703 }
1704 if (last) {
1705 __raid56_parity_write(last);
1706 }
1707 kfree(plug);
1708}
1709
1710/*
1711 * if the unplug comes from schedule, we have to push the
1712 * work off to a helper thread
1713 */
1714static void unplug_work(struct btrfs_work *work)
1715{
1716 struct btrfs_plug_cb *plug;
1717 plug = container_of(work, struct btrfs_plug_cb, work);
1718 run_plug(plug);
1719}
1720
1721static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule)
1722{
1723 struct btrfs_plug_cb *plug;
1724 plug = container_of(cb, struct btrfs_plug_cb, cb);
1725
1726 if (from_schedule) {
Liu Bo9e0af232014-08-15 23:36:53 +08001727 btrfs_init_work(&plug->work, btrfs_rmw_helper,
1728 unplug_work, NULL, NULL);
Qu Wenruod05a33a2014-02-28 10:46:11 +08001729 btrfs_queue_work(plug->info->rmw_workers,
1730 &plug->work);
Chris Mason6ac0f482013-01-31 14:42:28 -05001731 return;
1732 }
1733 run_plug(plug);
1734}
1735
1736/*
David Woodhouse53b381b2013-01-29 18:40:14 -05001737 * our main entry point for writes from the rest of the FS.
1738 */
1739int raid56_parity_write(struct btrfs_root *root, struct bio *bio,
Zhao Lei8e5cfb52015-01-20 15:11:33 +08001740 struct btrfs_bio *bbio, u64 stripe_len)
David Woodhouse53b381b2013-01-29 18:40:14 -05001741{
1742 struct btrfs_raid_bio *rbio;
Chris Mason6ac0f482013-01-31 14:42:28 -05001743 struct btrfs_plug_cb *plug = NULL;
1744 struct blk_plug_cb *cb;
Miao Xie42452152014-11-25 16:39:28 +08001745 int ret;
David Woodhouse53b381b2013-01-29 18:40:14 -05001746
Zhao Lei8e5cfb52015-01-20 15:11:33 +08001747 rbio = alloc_rbio(root, bbio, stripe_len);
Miao Xieaf8e2d12014-10-23 14:42:50 +08001748 if (IS_ERR(rbio)) {
Zhao Lei6e9606d2015-01-20 15:11:34 +08001749 btrfs_put_bbio(bbio);
David Woodhouse53b381b2013-01-29 18:40:14 -05001750 return PTR_ERR(rbio);
Miao Xieaf8e2d12014-10-23 14:42:50 +08001751 }
David Woodhouse53b381b2013-01-29 18:40:14 -05001752 bio_list_add(&rbio->bio_list, bio);
Kent Overstreet4f024f32013-10-11 15:44:27 -07001753 rbio->bio_list_bytes = bio->bi_iter.bi_size;
Miao Xie1b94b552014-11-06 16:14:21 +08001754 rbio->operation = BTRFS_RBIO_WRITE;
Chris Mason6ac0f482013-01-31 14:42:28 -05001755
Miao Xie42452152014-11-25 16:39:28 +08001756 btrfs_bio_counter_inc_noblocked(root->fs_info);
1757 rbio->generic_bio_cnt = 1;
1758
Chris Mason6ac0f482013-01-31 14:42:28 -05001759 /*
1760 * don't plug on full rbios, just get them out the door
1761 * as quickly as we can
1762 */
Miao Xie42452152014-11-25 16:39:28 +08001763 if (rbio_is_full(rbio)) {
1764 ret = full_stripe_write(rbio);
1765 if (ret)
1766 btrfs_bio_counter_dec(root->fs_info);
1767 return ret;
1768 }
Chris Mason6ac0f482013-01-31 14:42:28 -05001769
1770 cb = blk_check_plugged(btrfs_raid_unplug, root->fs_info,
1771 sizeof(*plug));
1772 if (cb) {
1773 plug = container_of(cb, struct btrfs_plug_cb, cb);
1774 if (!plug->info) {
1775 plug->info = root->fs_info;
1776 INIT_LIST_HEAD(&plug->rbio_list);
1777 }
1778 list_add_tail(&rbio->plug_list, &plug->rbio_list);
Miao Xie42452152014-11-25 16:39:28 +08001779 ret = 0;
Chris Mason6ac0f482013-01-31 14:42:28 -05001780 } else {
Miao Xie42452152014-11-25 16:39:28 +08001781 ret = __raid56_parity_write(rbio);
1782 if (ret)
1783 btrfs_bio_counter_dec(root->fs_info);
Chris Mason6ac0f482013-01-31 14:42:28 -05001784 }
Miao Xie42452152014-11-25 16:39:28 +08001785 return ret;
David Woodhouse53b381b2013-01-29 18:40:14 -05001786}
1787
1788/*
1789 * all parity reconstruction happens here. We've read in everything
1790 * we can find from the drives and this does the heavy lifting of
1791 * sorting the good from the bad.
1792 */
1793static void __raid_recover_end_io(struct btrfs_raid_bio *rbio)
1794{
1795 int pagenr, stripe;
1796 void **pointers;
1797 int faila = -1, failb = -1;
David Sterbaed6078f2014-06-05 01:59:57 +02001798 int nr_pages = DIV_ROUND_UP(rbio->stripe_len, PAGE_CACHE_SIZE);
David Woodhouse53b381b2013-01-29 18:40:14 -05001799 struct page *page;
1800 int err;
1801 int i;
1802
David Sterba31e818f2015-02-20 18:00:26 +01001803 pointers = kcalloc(rbio->real_stripes, sizeof(void *), GFP_NOFS);
David Woodhouse53b381b2013-01-29 18:40:14 -05001804 if (!pointers) {
1805 err = -ENOMEM;
1806 goto cleanup_io;
1807 }
1808
1809 faila = rbio->faila;
1810 failb = rbio->failb;
1811
Miao Xie1b94b552014-11-06 16:14:21 +08001812 if (rbio->operation == BTRFS_RBIO_READ_REBUILD) {
David Woodhouse53b381b2013-01-29 18:40:14 -05001813 spin_lock_irq(&rbio->bio_list_lock);
1814 set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags);
1815 spin_unlock_irq(&rbio->bio_list_lock);
1816 }
1817
1818 index_rbio_pages(rbio);
1819
1820 for (pagenr = 0; pagenr < nr_pages; pagenr++) {
Miao Xie5a6ac9e2014-11-06 17:20:58 +08001821 /*
1822 * Now we just use bitmap to mark the horizontal stripes in
1823 * which we have data when doing parity scrub.
1824 */
1825 if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB &&
1826 !test_bit(pagenr, rbio->dbitmap))
1827 continue;
1828
David Woodhouse53b381b2013-01-29 18:40:14 -05001829 /* setup our array of pointers with pages
1830 * from each stripe
1831 */
Miao Xie2c8cdd62014-11-14 16:06:25 +08001832 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
David Woodhouse53b381b2013-01-29 18:40:14 -05001833 /*
1834 * if we're rebuilding a read, we have to use
1835 * pages from the bio list
1836 */
Miao Xie1b94b552014-11-06 16:14:21 +08001837 if (rbio->operation == BTRFS_RBIO_READ_REBUILD &&
David Woodhouse53b381b2013-01-29 18:40:14 -05001838 (stripe == faila || stripe == failb)) {
1839 page = page_in_rbio(rbio, stripe, pagenr, 0);
1840 } else {
1841 page = rbio_stripe_page(rbio, stripe, pagenr);
1842 }
1843 pointers[stripe] = kmap(page);
1844 }
1845
1846 /* all raid6 handling here */
Zhao Lei10f11902015-01-20 15:11:43 +08001847 if (rbio->bbio->map_type & BTRFS_BLOCK_GROUP_RAID6) {
David Woodhouse53b381b2013-01-29 18:40:14 -05001848 /*
1849 * single failure, rebuild from parity raid5
1850 * style
1851 */
1852 if (failb < 0) {
1853 if (faila == rbio->nr_data) {
1854 /*
1855 * Just the P stripe has failed, without
1856 * a bad data or Q stripe.
1857 * TODO, we should redo the xor here.
1858 */
1859 err = -EIO;
1860 goto cleanup;
1861 }
1862 /*
1863 * a single failure in raid6 is rebuilt
1864 * in the pstripe code below
1865 */
1866 goto pstripe;
1867 }
1868
1869 /* make sure our ps and qs are in order */
1870 if (faila > failb) {
1871 int tmp = failb;
1872 failb = faila;
1873 faila = tmp;
1874 }
1875
1876 /* if the q stripe is failed, do a pstripe reconstruction
1877 * from the xors.
1878 * If both the q stripe and the P stripe are failed, we're
1879 * here due to a crc mismatch and we can't give them the
1880 * data they want
1881 */
Zhao Lei8e5cfb52015-01-20 15:11:33 +08001882 if (rbio->bbio->raid_map[failb] == RAID6_Q_STRIPE) {
1883 if (rbio->bbio->raid_map[faila] ==
1884 RAID5_P_STRIPE) {
David Woodhouse53b381b2013-01-29 18:40:14 -05001885 err = -EIO;
1886 goto cleanup;
1887 }
1888 /*
1889 * otherwise we have one bad data stripe and
1890 * a good P stripe. raid5!
1891 */
1892 goto pstripe;
1893 }
1894
Zhao Lei8e5cfb52015-01-20 15:11:33 +08001895 if (rbio->bbio->raid_map[failb] == RAID5_P_STRIPE) {
Miao Xie2c8cdd62014-11-14 16:06:25 +08001896 raid6_datap_recov(rbio->real_stripes,
David Woodhouse53b381b2013-01-29 18:40:14 -05001897 PAGE_SIZE, faila, pointers);
1898 } else {
Miao Xie2c8cdd62014-11-14 16:06:25 +08001899 raid6_2data_recov(rbio->real_stripes,
David Woodhouse53b381b2013-01-29 18:40:14 -05001900 PAGE_SIZE, faila, failb,
1901 pointers);
1902 }
1903 } else {
1904 void *p;
1905
1906 /* rebuild from P stripe here (raid5 or raid6) */
1907 BUG_ON(failb != -1);
1908pstripe:
1909 /* Copy parity block into failed block to start with */
1910 memcpy(pointers[faila],
1911 pointers[rbio->nr_data],
1912 PAGE_CACHE_SIZE);
1913
1914 /* rearrange the pointer array */
1915 p = pointers[faila];
1916 for (stripe = faila; stripe < rbio->nr_data - 1; stripe++)
1917 pointers[stripe] = pointers[stripe + 1];
1918 pointers[rbio->nr_data - 1] = p;
1919
1920 /* xor in the rest */
1921 run_xor(pointers, rbio->nr_data - 1, PAGE_CACHE_SIZE);
1922 }
1923 /* if we're doing this rebuild as part of an rmw, go through
1924 * and set all of our private rbio pages in the
1925 * failed stripes as uptodate. This way finish_rmw will
1926 * know they can be trusted. If this was a read reconstruction,
1927 * other endio functions will fiddle the uptodate bits
1928 */
Miao Xie1b94b552014-11-06 16:14:21 +08001929 if (rbio->operation == BTRFS_RBIO_WRITE) {
David Woodhouse53b381b2013-01-29 18:40:14 -05001930 for (i = 0; i < nr_pages; i++) {
1931 if (faila != -1) {
1932 page = rbio_stripe_page(rbio, faila, i);
1933 SetPageUptodate(page);
1934 }
1935 if (failb != -1) {
1936 page = rbio_stripe_page(rbio, failb, i);
1937 SetPageUptodate(page);
1938 }
1939 }
1940 }
Miao Xie2c8cdd62014-11-14 16:06:25 +08001941 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
David Woodhouse53b381b2013-01-29 18:40:14 -05001942 /*
1943 * if we're rebuilding a read, we have to use
1944 * pages from the bio list
1945 */
Miao Xie1b94b552014-11-06 16:14:21 +08001946 if (rbio->operation == BTRFS_RBIO_READ_REBUILD &&
David Woodhouse53b381b2013-01-29 18:40:14 -05001947 (stripe == faila || stripe == failb)) {
1948 page = page_in_rbio(rbio, stripe, pagenr, 0);
1949 } else {
1950 page = rbio_stripe_page(rbio, stripe, pagenr);
1951 }
1952 kunmap(page);
1953 }
1954 }
1955
1956 err = 0;
1957cleanup:
1958 kfree(pointers);
1959
1960cleanup_io:
Miao Xie1b94b552014-11-06 16:14:21 +08001961 if (rbio->operation == BTRFS_RBIO_READ_REBUILD) {
Zhao Lei6e9606d2015-01-20 15:11:34 +08001962 if (err == 0)
Chris Mason4ae10b32013-01-31 14:42:09 -05001963 cache_rbio_pages(rbio);
1964 else
1965 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
1966
David Woodhouse53b381b2013-01-29 18:40:14 -05001967 rbio_orig_end_io(rbio, err, err == 0);
1968 } else if (err == 0) {
1969 rbio->faila = -1;
1970 rbio->failb = -1;
Miao Xie5a6ac9e2014-11-06 17:20:58 +08001971
1972 if (rbio->operation == BTRFS_RBIO_WRITE)
1973 finish_rmw(rbio);
1974 else if (rbio->operation == BTRFS_RBIO_PARITY_SCRUB)
1975 finish_parity_scrub(rbio, 0);
1976 else
1977 BUG();
David Woodhouse53b381b2013-01-29 18:40:14 -05001978 } else {
1979 rbio_orig_end_io(rbio, err, 0);
1980 }
1981}
1982
1983/*
1984 * This is called only for stripes we've read from disk to
1985 * reconstruct the parity.
1986 */
1987static void raid_recover_end_io(struct bio *bio, int err)
1988{
1989 struct btrfs_raid_bio *rbio = bio->bi_private;
1990
1991 /*
1992 * we only read stripe pages off the disk, set them
1993 * up to date if there were no errors
1994 */
1995 if (err)
1996 fail_bio_stripe(rbio, bio);
1997 else
1998 set_bio_pages_uptodate(bio);
1999 bio_put(bio);
2000
Miao Xieb89e1b02014-10-15 11:18:44 +08002001 if (!atomic_dec_and_test(&rbio->stripes_pending))
David Woodhouse53b381b2013-01-29 18:40:14 -05002002 return;
2003
Miao Xieb89e1b02014-10-15 11:18:44 +08002004 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
David Woodhouse53b381b2013-01-29 18:40:14 -05002005 rbio_orig_end_io(rbio, -EIO, 0);
2006 else
2007 __raid_recover_end_io(rbio);
2008}
2009
2010/*
2011 * reads everything we need off the disk to reconstruct
2012 * the parity. endio handlers trigger final reconstruction
2013 * when the IO is done.
2014 *
2015 * This is used both for reads from the higher layers and for
2016 * parity construction required to finish a rmw cycle.
2017 */
2018static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
2019{
2020 int bios_to_read = 0;
David Woodhouse53b381b2013-01-29 18:40:14 -05002021 struct bio_list bio_list;
2022 int ret;
David Sterbaed6078f2014-06-05 01:59:57 +02002023 int nr_pages = DIV_ROUND_UP(rbio->stripe_len, PAGE_CACHE_SIZE);
David Woodhouse53b381b2013-01-29 18:40:14 -05002024 int pagenr;
2025 int stripe;
2026 struct bio *bio;
2027
2028 bio_list_init(&bio_list);
2029
2030 ret = alloc_rbio_pages(rbio);
2031 if (ret)
2032 goto cleanup;
2033
Miao Xieb89e1b02014-10-15 11:18:44 +08002034 atomic_set(&rbio->error, 0);
David Woodhouse53b381b2013-01-29 18:40:14 -05002035
2036 /*
Chris Mason4ae10b32013-01-31 14:42:09 -05002037 * read everything that hasn't failed. Thanks to the
2038 * stripe cache, it is possible that some or all of these
2039 * pages are going to be uptodate.
David Woodhouse53b381b2013-01-29 18:40:14 -05002040 */
Miao Xie2c8cdd62014-11-14 16:06:25 +08002041 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
Liu Bo55883832014-06-24 15:39:16 +08002042 if (rbio->faila == stripe || rbio->failb == stripe) {
Miao Xieb89e1b02014-10-15 11:18:44 +08002043 atomic_inc(&rbio->error);
David Woodhouse53b381b2013-01-29 18:40:14 -05002044 continue;
Liu Bo55883832014-06-24 15:39:16 +08002045 }
David Woodhouse53b381b2013-01-29 18:40:14 -05002046
2047 for (pagenr = 0; pagenr < nr_pages; pagenr++) {
2048 struct page *p;
2049
2050 /*
2051 * the rmw code may have already read this
2052 * page in
2053 */
2054 p = rbio_stripe_page(rbio, stripe, pagenr);
2055 if (PageUptodate(p))
2056 continue;
2057
2058 ret = rbio_add_io_page(rbio, &bio_list,
2059 rbio_stripe_page(rbio, stripe, pagenr),
2060 stripe, pagenr, rbio->stripe_len);
2061 if (ret < 0)
2062 goto cleanup;
2063 }
2064 }
2065
2066 bios_to_read = bio_list_size(&bio_list);
2067 if (!bios_to_read) {
2068 /*
2069 * we might have no bios to read just because the pages
2070 * were up to date, or we might have no bios to read because
2071 * the devices were gone.
2072 */
Miao Xieb89e1b02014-10-15 11:18:44 +08002073 if (atomic_read(&rbio->error) <= rbio->bbio->max_errors) {
David Woodhouse53b381b2013-01-29 18:40:14 -05002074 __raid_recover_end_io(rbio);
2075 goto out;
2076 } else {
2077 goto cleanup;
2078 }
2079 }
2080
2081 /*
2082 * the bbio may be freed once we submit the last bio. Make sure
2083 * not to touch it after that
2084 */
Miao Xieb89e1b02014-10-15 11:18:44 +08002085 atomic_set(&rbio->stripes_pending, bios_to_read);
David Woodhouse53b381b2013-01-29 18:40:14 -05002086 while (1) {
2087 bio = bio_list_pop(&bio_list);
2088 if (!bio)
2089 break;
2090
2091 bio->bi_private = rbio;
2092 bio->bi_end_io = raid_recover_end_io;
2093
2094 btrfs_bio_wq_end_io(rbio->fs_info, bio,
2095 BTRFS_WQ_ENDIO_RAID56);
2096
2097 BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
2098 submit_bio(READ, bio);
2099 }
2100out:
2101 return 0;
2102
2103cleanup:
Miao Xie1b94b552014-11-06 16:14:21 +08002104 if (rbio->operation == BTRFS_RBIO_READ_REBUILD)
David Woodhouse53b381b2013-01-29 18:40:14 -05002105 rbio_orig_end_io(rbio, -EIO, 0);
2106 return -EIO;
2107}
2108
2109/*
2110 * the main entry point for reads from the higher layers. This
2111 * is really only called when the normal read path had a failure,
2112 * so we assume the bio they send down corresponds to a failed part
2113 * of the drive.
2114 */
2115int raid56_parity_recover(struct btrfs_root *root, struct bio *bio,
Zhao Lei8e5cfb52015-01-20 15:11:33 +08002116 struct btrfs_bio *bbio, u64 stripe_len,
2117 int mirror_num, int generic_io)
David Woodhouse53b381b2013-01-29 18:40:14 -05002118{
2119 struct btrfs_raid_bio *rbio;
2120 int ret;
2121
Zhao Lei8e5cfb52015-01-20 15:11:33 +08002122 rbio = alloc_rbio(root, bbio, stripe_len);
Miao Xieaf8e2d12014-10-23 14:42:50 +08002123 if (IS_ERR(rbio)) {
Zhao Lei6e9606d2015-01-20 15:11:34 +08002124 if (generic_io)
2125 btrfs_put_bbio(bbio);
David Woodhouse53b381b2013-01-29 18:40:14 -05002126 return PTR_ERR(rbio);
Miao Xieaf8e2d12014-10-23 14:42:50 +08002127 }
David Woodhouse53b381b2013-01-29 18:40:14 -05002128
Miao Xie1b94b552014-11-06 16:14:21 +08002129 rbio->operation = BTRFS_RBIO_READ_REBUILD;
David Woodhouse53b381b2013-01-29 18:40:14 -05002130 bio_list_add(&rbio->bio_list, bio);
Kent Overstreet4f024f32013-10-11 15:44:27 -07002131 rbio->bio_list_bytes = bio->bi_iter.bi_size;
David Woodhouse53b381b2013-01-29 18:40:14 -05002132
2133 rbio->faila = find_logical_bio_stripe(rbio, bio);
2134 if (rbio->faila == -1) {
2135 BUG();
Zhao Lei6e9606d2015-01-20 15:11:34 +08002136 if (generic_io)
2137 btrfs_put_bbio(bbio);
David Woodhouse53b381b2013-01-29 18:40:14 -05002138 kfree(rbio);
2139 return -EIO;
2140 }
2141
Miao Xie42452152014-11-25 16:39:28 +08002142 if (generic_io) {
2143 btrfs_bio_counter_inc_noblocked(root->fs_info);
2144 rbio->generic_bio_cnt = 1;
2145 } else {
Zhao Lei6e9606d2015-01-20 15:11:34 +08002146 btrfs_get_bbio(bbio);
Miao Xie42452152014-11-25 16:39:28 +08002147 }
2148
David Woodhouse53b381b2013-01-29 18:40:14 -05002149 /*
2150 * reconstruct from the q stripe if they are
2151 * asking for mirror 3
2152 */
2153 if (mirror_num == 3)
Miao Xie2c8cdd62014-11-14 16:06:25 +08002154 rbio->failb = rbio->real_stripes - 2;
David Woodhouse53b381b2013-01-29 18:40:14 -05002155
2156 ret = lock_stripe_add(rbio);
2157
2158 /*
2159 * __raid56_parity_recover will end the bio with
2160 * any errors it hits. We don't want to return
2161 * its error value up the stack because our caller
2162 * will end up calling bio_endio with any nonzero
2163 * return
2164 */
2165 if (ret == 0)
2166 __raid56_parity_recover(rbio);
2167 /*
2168 * our rbio has been added to the list of
2169 * rbios that will be handled after the
2170 * currently lock owner is done
2171 */
2172 return 0;
2173
2174}
2175
2176static void rmw_work(struct btrfs_work *work)
2177{
2178 struct btrfs_raid_bio *rbio;
2179
2180 rbio = container_of(work, struct btrfs_raid_bio, work);
2181 raid56_rmw_stripe(rbio);
2182}
2183
2184static void read_rebuild_work(struct btrfs_work *work)
2185{
2186 struct btrfs_raid_bio *rbio;
2187
2188 rbio = container_of(work, struct btrfs_raid_bio, work);
2189 __raid56_parity_recover(rbio);
2190}
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002191
2192/*
2193 * The following code is used to scrub/replace the parity stripe
2194 *
2195 * Note: We need make sure all the pages that add into the scrub/replace
2196 * raid bio are correct and not be changed during the scrub/replace. That
2197 * is those pages just hold metadata or file data with checksum.
2198 */
2199
2200struct btrfs_raid_bio *
2201raid56_parity_alloc_scrub_rbio(struct btrfs_root *root, struct bio *bio,
Zhao Lei8e5cfb52015-01-20 15:11:33 +08002202 struct btrfs_bio *bbio, u64 stripe_len,
2203 struct btrfs_device *scrub_dev,
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002204 unsigned long *dbitmap, int stripe_nsectors)
2205{
2206 struct btrfs_raid_bio *rbio;
2207 int i;
2208
Zhao Lei8e5cfb52015-01-20 15:11:33 +08002209 rbio = alloc_rbio(root, bbio, stripe_len);
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002210 if (IS_ERR(rbio))
2211 return NULL;
2212 bio_list_add(&rbio->bio_list, bio);
2213 /*
2214 * This is a special bio which is used to hold the completion handler
2215 * and make the scrub rbio is similar to the other types
2216 */
2217 ASSERT(!bio->bi_iter.bi_size);
2218 rbio->operation = BTRFS_RBIO_PARITY_SCRUB;
2219
Miao Xie2c8cdd62014-11-14 16:06:25 +08002220 for (i = 0; i < rbio->real_stripes; i++) {
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002221 if (bbio->stripes[i].dev == scrub_dev) {
2222 rbio->scrubp = i;
2223 break;
2224 }
2225 }
2226
2227 /* Now we just support the sectorsize equals to page size */
2228 ASSERT(root->sectorsize == PAGE_SIZE);
2229 ASSERT(rbio->stripe_npages == stripe_nsectors);
2230 bitmap_copy(rbio->dbitmap, dbitmap, stripe_nsectors);
2231
2232 return rbio;
2233}
2234
2235void raid56_parity_add_scrub_pages(struct btrfs_raid_bio *rbio,
2236 struct page *page, u64 logical)
2237{
2238 int stripe_offset;
2239 int index;
2240
Zhao Lei8e5cfb52015-01-20 15:11:33 +08002241 ASSERT(logical >= rbio->bbio->raid_map[0]);
2242 ASSERT(logical + PAGE_SIZE <= rbio->bbio->raid_map[0] +
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002243 rbio->stripe_len * rbio->nr_data);
Zhao Lei8e5cfb52015-01-20 15:11:33 +08002244 stripe_offset = (int)(logical - rbio->bbio->raid_map[0]);
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002245 index = stripe_offset >> PAGE_CACHE_SHIFT;
2246 rbio->bio_pages[index] = page;
2247}
2248
2249/*
2250 * We just scrub the parity that we have correct data on the same horizontal,
2251 * so we needn't allocate all pages for all the stripes.
2252 */
2253static int alloc_rbio_essential_pages(struct btrfs_raid_bio *rbio)
2254{
2255 int i;
2256 int bit;
2257 int index;
2258 struct page *page;
2259
2260 for_each_set_bit(bit, rbio->dbitmap, rbio->stripe_npages) {
Miao Xie2c8cdd62014-11-14 16:06:25 +08002261 for (i = 0; i < rbio->real_stripes; i++) {
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002262 index = i * rbio->stripe_npages + bit;
2263 if (rbio->stripe_pages[index])
2264 continue;
2265
2266 page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2267 if (!page)
2268 return -ENOMEM;
2269 rbio->stripe_pages[index] = page;
2270 ClearPageUptodate(page);
2271 }
2272 }
2273 return 0;
2274}
2275
2276/*
2277 * end io function used by finish_rmw. When we finally
2278 * get here, we've written a full stripe
2279 */
2280static void raid_write_parity_end_io(struct bio *bio, int err)
2281{
2282 struct btrfs_raid_bio *rbio = bio->bi_private;
2283
2284 if (err)
2285 fail_bio_stripe(rbio, bio);
2286
2287 bio_put(bio);
2288
2289 if (!atomic_dec_and_test(&rbio->stripes_pending))
2290 return;
2291
2292 err = 0;
2293
2294 if (atomic_read(&rbio->error))
2295 err = -EIO;
2296
2297 rbio_orig_end_io(rbio, err, 0);
2298}
2299
2300static noinline void finish_parity_scrub(struct btrfs_raid_bio *rbio,
2301 int need_check)
2302{
Miao Xie76035972014-11-14 17:45:42 +08002303 struct btrfs_bio *bbio = rbio->bbio;
Miao Xie2c8cdd62014-11-14 16:06:25 +08002304 void *pointers[rbio->real_stripes];
Miao Xie76035972014-11-14 17:45:42 +08002305 DECLARE_BITMAP(pbitmap, rbio->stripe_npages);
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002306 int nr_data = rbio->nr_data;
2307 int stripe;
2308 int pagenr;
2309 int p_stripe = -1;
2310 int q_stripe = -1;
2311 struct page *p_page = NULL;
2312 struct page *q_page = NULL;
2313 struct bio_list bio_list;
2314 struct bio *bio;
Miao Xie76035972014-11-14 17:45:42 +08002315 int is_replace = 0;
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002316 int ret;
2317
2318 bio_list_init(&bio_list);
2319
Miao Xie2c8cdd62014-11-14 16:06:25 +08002320 if (rbio->real_stripes - rbio->nr_data == 1) {
2321 p_stripe = rbio->real_stripes - 1;
2322 } else if (rbio->real_stripes - rbio->nr_data == 2) {
2323 p_stripe = rbio->real_stripes - 2;
2324 q_stripe = rbio->real_stripes - 1;
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002325 } else {
2326 BUG();
2327 }
2328
Miao Xie76035972014-11-14 17:45:42 +08002329 if (bbio->num_tgtdevs && bbio->tgtdev_map[rbio->scrubp]) {
2330 is_replace = 1;
2331 bitmap_copy(pbitmap, rbio->dbitmap, rbio->stripe_npages);
2332 }
2333
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002334 /*
2335 * Because the higher layers(scrubber) are unlikely to
2336 * use this area of the disk again soon, so don't cache
2337 * it.
2338 */
2339 clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags);
2340
2341 if (!need_check)
2342 goto writeback;
2343
2344 p_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2345 if (!p_page)
2346 goto cleanup;
2347 SetPageUptodate(p_page);
2348
2349 if (q_stripe != -1) {
2350 q_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
2351 if (!q_page) {
2352 __free_page(p_page);
2353 goto cleanup;
2354 }
2355 SetPageUptodate(q_page);
2356 }
2357
2358 atomic_set(&rbio->error, 0);
2359
2360 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2361 struct page *p;
2362 void *parity;
2363 /* first collect one page from each data stripe */
2364 for (stripe = 0; stripe < nr_data; stripe++) {
2365 p = page_in_rbio(rbio, stripe, pagenr, 0);
2366 pointers[stripe] = kmap(p);
2367 }
2368
2369 /* then add the parity stripe */
2370 pointers[stripe++] = kmap(p_page);
2371
2372 if (q_stripe != -1) {
2373
2374 /*
2375 * raid6, add the qstripe and call the
2376 * library function to fill in our p/q
2377 */
2378 pointers[stripe++] = kmap(q_page);
2379
Miao Xie2c8cdd62014-11-14 16:06:25 +08002380 raid6_call.gen_syndrome(rbio->real_stripes, PAGE_SIZE,
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002381 pointers);
2382 } else {
2383 /* raid5 */
2384 memcpy(pointers[nr_data], pointers[0], PAGE_SIZE);
2385 run_xor(pointers + 1, nr_data - 1, PAGE_CACHE_SIZE);
2386 }
2387
2388 /* Check scrubbing pairty and repair it */
2389 p = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2390 parity = kmap(p);
2391 if (memcmp(parity, pointers[rbio->scrubp], PAGE_CACHE_SIZE))
2392 memcpy(parity, pointers[rbio->scrubp], PAGE_CACHE_SIZE);
2393 else
2394 /* Parity is right, needn't writeback */
2395 bitmap_clear(rbio->dbitmap, pagenr, 1);
2396 kunmap(p);
2397
Miao Xie2c8cdd62014-11-14 16:06:25 +08002398 for (stripe = 0; stripe < rbio->real_stripes; stripe++)
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002399 kunmap(page_in_rbio(rbio, stripe, pagenr, 0));
2400 }
2401
2402 __free_page(p_page);
2403 if (q_page)
2404 __free_page(q_page);
2405
2406writeback:
2407 /*
2408 * time to start writing. Make bios for everything from the
2409 * higher layers (the bio_list in our rbio) and our p/q. Ignore
2410 * everything else.
2411 */
2412 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2413 struct page *page;
2414
2415 page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2416 ret = rbio_add_io_page(rbio, &bio_list,
2417 page, rbio->scrubp, pagenr, rbio->stripe_len);
2418 if (ret)
2419 goto cleanup;
2420 }
2421
Miao Xie76035972014-11-14 17:45:42 +08002422 if (!is_replace)
2423 goto submit_write;
2424
2425 for_each_set_bit(pagenr, pbitmap, rbio->stripe_npages) {
2426 struct page *page;
2427
2428 page = rbio_stripe_page(rbio, rbio->scrubp, pagenr);
2429 ret = rbio_add_io_page(rbio, &bio_list, page,
2430 bbio->tgtdev_map[rbio->scrubp],
2431 pagenr, rbio->stripe_len);
2432 if (ret)
2433 goto cleanup;
2434 }
2435
2436submit_write:
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002437 nr_data = bio_list_size(&bio_list);
2438 if (!nr_data) {
2439 /* Every parity is right */
2440 rbio_orig_end_io(rbio, 0, 0);
2441 return;
2442 }
2443
2444 atomic_set(&rbio->stripes_pending, nr_data);
2445
2446 while (1) {
2447 bio = bio_list_pop(&bio_list);
2448 if (!bio)
2449 break;
2450
2451 bio->bi_private = rbio;
2452 bio->bi_end_io = raid_write_parity_end_io;
2453 BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
2454 submit_bio(WRITE, bio);
2455 }
2456 return;
2457
2458cleanup:
2459 rbio_orig_end_io(rbio, -EIO, 0);
2460}
2461
2462static inline int is_data_stripe(struct btrfs_raid_bio *rbio, int stripe)
2463{
2464 if (stripe >= 0 && stripe < rbio->nr_data)
2465 return 1;
2466 return 0;
2467}
2468
2469/*
2470 * While we're doing the parity check and repair, we could have errors
2471 * in reading pages off the disk. This checks for errors and if we're
2472 * not able to read the page it'll trigger parity reconstruction. The
2473 * parity scrub will be finished after we've reconstructed the failed
2474 * stripes
2475 */
2476static void validate_rbio_for_parity_scrub(struct btrfs_raid_bio *rbio)
2477{
2478 if (atomic_read(&rbio->error) > rbio->bbio->max_errors)
2479 goto cleanup;
2480
2481 if (rbio->faila >= 0 || rbio->failb >= 0) {
2482 int dfail = 0, failp = -1;
2483
2484 if (is_data_stripe(rbio, rbio->faila))
2485 dfail++;
2486 else if (is_parity_stripe(rbio->faila))
2487 failp = rbio->faila;
2488
2489 if (is_data_stripe(rbio, rbio->failb))
2490 dfail++;
2491 else if (is_parity_stripe(rbio->failb))
2492 failp = rbio->failb;
2493
2494 /*
2495 * Because we can not use a scrubbing parity to repair
2496 * the data, so the capability of the repair is declined.
2497 * (In the case of RAID5, we can not repair anything)
2498 */
2499 if (dfail > rbio->bbio->max_errors - 1)
2500 goto cleanup;
2501
2502 /*
2503 * If all data is good, only parity is correctly, just
2504 * repair the parity.
2505 */
2506 if (dfail == 0) {
2507 finish_parity_scrub(rbio, 0);
2508 return;
2509 }
2510
2511 /*
2512 * Here means we got one corrupted data stripe and one
2513 * corrupted parity on RAID6, if the corrupted parity
2514 * is scrubbing parity, luckly, use the other one to repair
2515 * the data, or we can not repair the data stripe.
2516 */
2517 if (failp != rbio->scrubp)
2518 goto cleanup;
2519
2520 __raid_recover_end_io(rbio);
2521 } else {
2522 finish_parity_scrub(rbio, 1);
2523 }
2524 return;
2525
2526cleanup:
2527 rbio_orig_end_io(rbio, -EIO, 0);
2528}
2529
2530/*
2531 * end io for the read phase of the rmw cycle. All the bios here are physical
2532 * stripe bios we've read from the disk so we can recalculate the parity of the
2533 * stripe.
2534 *
2535 * This will usually kick off finish_rmw once all the bios are read in, but it
2536 * may trigger parity reconstruction if we had any errors along the way
2537 */
2538static void raid56_parity_scrub_end_io(struct bio *bio, int err)
2539{
2540 struct btrfs_raid_bio *rbio = bio->bi_private;
2541
2542 if (err)
2543 fail_bio_stripe(rbio, bio);
2544 else
2545 set_bio_pages_uptodate(bio);
2546
2547 bio_put(bio);
2548
2549 if (!atomic_dec_and_test(&rbio->stripes_pending))
2550 return;
2551
2552 /*
2553 * this will normally call finish_rmw to start our write
2554 * but if there are any failed stripes we'll reconstruct
2555 * from parity first
2556 */
2557 validate_rbio_for_parity_scrub(rbio);
2558}
2559
2560static void raid56_parity_scrub_stripe(struct btrfs_raid_bio *rbio)
2561{
2562 int bios_to_read = 0;
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002563 struct bio_list bio_list;
2564 int ret;
2565 int pagenr;
2566 int stripe;
2567 struct bio *bio;
2568
2569 ret = alloc_rbio_essential_pages(rbio);
2570 if (ret)
2571 goto cleanup;
2572
2573 bio_list_init(&bio_list);
2574
2575 atomic_set(&rbio->error, 0);
2576 /*
2577 * build a list of bios to read all the missing parts of this
2578 * stripe
2579 */
Miao Xie2c8cdd62014-11-14 16:06:25 +08002580 for (stripe = 0; stripe < rbio->real_stripes; stripe++) {
Miao Xie5a6ac9e2014-11-06 17:20:58 +08002581 for_each_set_bit(pagenr, rbio->dbitmap, rbio->stripe_npages) {
2582 struct page *page;
2583 /*
2584 * we want to find all the pages missing from
2585 * the rbio and read them from the disk. If
2586 * page_in_rbio finds a page in the bio list
2587 * we don't need to read it off the stripe.
2588 */
2589 page = page_in_rbio(rbio, stripe, pagenr, 1);
2590 if (page)
2591 continue;
2592
2593 page = rbio_stripe_page(rbio, stripe, pagenr);
2594 /*
2595 * the bio cache may have handed us an uptodate
2596 * page. If so, be happy and use it
2597 */
2598 if (PageUptodate(page))
2599 continue;
2600
2601 ret = rbio_add_io_page(rbio, &bio_list, page,
2602 stripe, pagenr, rbio->stripe_len);
2603 if (ret)
2604 goto cleanup;
2605 }
2606 }
2607
2608 bios_to_read = bio_list_size(&bio_list);
2609 if (!bios_to_read) {
2610 /*
2611 * this can happen if others have merged with
2612 * us, it means there is nothing left to read.
2613 * But if there are missing devices it may not be
2614 * safe to do the full stripe write yet.
2615 */
2616 goto finish;
2617 }
2618
2619 /*
2620 * the bbio may be freed once we submit the last bio. Make sure
2621 * not to touch it after that
2622 */
2623 atomic_set(&rbio->stripes_pending, bios_to_read);
2624 while (1) {
2625 bio = bio_list_pop(&bio_list);
2626 if (!bio)
2627 break;
2628
2629 bio->bi_private = rbio;
2630 bio->bi_end_io = raid56_parity_scrub_end_io;
2631
2632 btrfs_bio_wq_end_io(rbio->fs_info, bio,
2633 BTRFS_WQ_ENDIO_RAID56);
2634
2635 BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags));
2636 submit_bio(READ, bio);
2637 }
2638 /* the actual write will happen once the reads are done */
2639 return;
2640
2641cleanup:
2642 rbio_orig_end_io(rbio, -EIO, 0);
2643 return;
2644
2645finish:
2646 validate_rbio_for_parity_scrub(rbio);
2647}
2648
2649static void scrub_parity_work(struct btrfs_work *work)
2650{
2651 struct btrfs_raid_bio *rbio;
2652
2653 rbio = container_of(work, struct btrfs_raid_bio, work);
2654 raid56_parity_scrub_stripe(rbio);
2655}
2656
2657static void async_scrub_parity(struct btrfs_raid_bio *rbio)
2658{
2659 btrfs_init_work(&rbio->work, btrfs_rmw_helper,
2660 scrub_parity_work, NULL, NULL);
2661
2662 btrfs_queue_work(rbio->fs_info->rmw_workers,
2663 &rbio->work);
2664}
2665
2666void raid56_parity_submit_scrub_rbio(struct btrfs_raid_bio *rbio)
2667{
2668 if (!lock_stripe_add(rbio))
2669 async_scrub_parity(rbio);
2670}