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53b381b3 DW |
1 | /* |
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> | |
d7011f5b | 34 | #include <linux/vmalloc.h> |
53b381b3 | 35 | #include <asm/div64.h> |
53b381b3 DW |
36 | #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 | ||
4ae10b3a CM |
50 | /* |
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 | ||
61 | ||
62 | #define RBIO_CACHE_SIZE 1024 | |
63 | ||
53b381b3 DW |
64 | struct btrfs_raid_bio { |
65 | struct btrfs_fs_info *fs_info; | |
66 | struct btrfs_bio *bbio; | |
67 | ||
68 | /* | |
69 | * logical block numbers for the start of each stripe | |
70 | * The last one or two are p/q. These are sorted, | |
71 | * so raid_map[0] is the start of our full stripe | |
72 | */ | |
73 | u64 *raid_map; | |
74 | ||
75 | /* while we're doing rmw on a stripe | |
76 | * we put it into a hash table so we can | |
77 | * lock the stripe and merge more rbios | |
78 | * into it. | |
79 | */ | |
80 | struct list_head hash_list; | |
81 | ||
4ae10b3a CM |
82 | /* |
83 | * LRU list for the stripe cache | |
84 | */ | |
85 | struct list_head stripe_cache; | |
86 | ||
53b381b3 DW |
87 | /* |
88 | * for scheduling work in the helper threads | |
89 | */ | |
90 | struct btrfs_work work; | |
91 | ||
92 | /* | |
93 | * bio list and bio_list_lock are used | |
94 | * to add more bios into the stripe | |
95 | * in hopes of avoiding the full rmw | |
96 | */ | |
97 | struct bio_list bio_list; | |
98 | spinlock_t bio_list_lock; | |
99 | ||
6ac0f488 CM |
100 | /* also protected by the bio_list_lock, the |
101 | * plug list is used by the plugging code | |
102 | * to collect partial bios while plugged. The | |
103 | * stripe locking code also uses it to hand off | |
53b381b3 DW |
104 | * the stripe lock to the next pending IO |
105 | */ | |
106 | struct list_head plug_list; | |
107 | ||
108 | /* | |
109 | * flags that tell us if it is safe to | |
110 | * merge with this bio | |
111 | */ | |
112 | unsigned long flags; | |
113 | ||
114 | /* size of each individual stripe on disk */ | |
115 | int stripe_len; | |
116 | ||
117 | /* number of data stripes (no p/q) */ | |
118 | int nr_data; | |
119 | ||
120 | /* | |
121 | * set if we're doing a parity rebuild | |
122 | * for a read from higher up, which is handled | |
123 | * differently from a parity rebuild as part of | |
124 | * rmw | |
125 | */ | |
126 | int read_rebuild; | |
127 | ||
128 | /* first bad stripe */ | |
129 | int faila; | |
130 | ||
131 | /* second bad stripe (for raid6 use) */ | |
132 | int failb; | |
133 | ||
134 | /* | |
135 | * number of pages needed to represent the full | |
136 | * stripe | |
137 | */ | |
138 | int nr_pages; | |
139 | ||
140 | /* | |
141 | * size of all the bios in the bio_list. This | |
142 | * helps us decide if the rbio maps to a full | |
143 | * stripe or not | |
144 | */ | |
145 | int bio_list_bytes; | |
146 | ||
147 | atomic_t refs; | |
148 | ||
149 | /* | |
150 | * these are two arrays of pointers. We allocate the | |
151 | * rbio big enough to hold them both and setup their | |
152 | * locations when the rbio is allocated | |
153 | */ | |
154 | ||
155 | /* pointers to pages that we allocated for | |
156 | * reading/writing stripes directly from the disk (including P/Q) | |
157 | */ | |
158 | struct page **stripe_pages; | |
159 | ||
160 | /* | |
161 | * pointers to the pages in the bio_list. Stored | |
162 | * here for faster lookup | |
163 | */ | |
164 | struct page **bio_pages; | |
165 | }; | |
166 | ||
167 | static int __raid56_parity_recover(struct btrfs_raid_bio *rbio); | |
168 | static noinline void finish_rmw(struct btrfs_raid_bio *rbio); | |
169 | static void rmw_work(struct btrfs_work *work); | |
170 | static void read_rebuild_work(struct btrfs_work *work); | |
171 | static void async_rmw_stripe(struct btrfs_raid_bio *rbio); | |
172 | static void async_read_rebuild(struct btrfs_raid_bio *rbio); | |
173 | static int fail_bio_stripe(struct btrfs_raid_bio *rbio, struct bio *bio); | |
174 | static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed); | |
175 | static void __free_raid_bio(struct btrfs_raid_bio *rbio); | |
176 | static void index_rbio_pages(struct btrfs_raid_bio *rbio); | |
177 | static int alloc_rbio_pages(struct btrfs_raid_bio *rbio); | |
178 | ||
179 | /* | |
180 | * the stripe hash table is used for locking, and to collect | |
181 | * bios in hopes of making a full stripe | |
182 | */ | |
183 | int btrfs_alloc_stripe_hash_table(struct btrfs_fs_info *info) | |
184 | { | |
185 | struct btrfs_stripe_hash_table *table; | |
186 | struct btrfs_stripe_hash_table *x; | |
187 | struct btrfs_stripe_hash *cur; | |
188 | struct btrfs_stripe_hash *h; | |
189 | int num_entries = 1 << BTRFS_STRIPE_HASH_TABLE_BITS; | |
190 | int i; | |
83c8266a | 191 | int table_size; |
53b381b3 DW |
192 | |
193 | if (info->stripe_hash_table) | |
194 | return 0; | |
195 | ||
83c8266a DS |
196 | /* |
197 | * The table is large, starting with order 4 and can go as high as | |
198 | * order 7 in case lock debugging is turned on. | |
199 | * | |
200 | * Try harder to allocate and fallback to vmalloc to lower the chance | |
201 | * of a failing mount. | |
202 | */ | |
203 | table_size = sizeof(*table) + sizeof(*h) * num_entries; | |
204 | table = kzalloc(table_size, GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT); | |
205 | if (!table) { | |
206 | table = vzalloc(table_size); | |
207 | if (!table) | |
208 | return -ENOMEM; | |
209 | } | |
53b381b3 | 210 | |
4ae10b3a CM |
211 | spin_lock_init(&table->cache_lock); |
212 | INIT_LIST_HEAD(&table->stripe_cache); | |
213 | ||
53b381b3 DW |
214 | h = table->table; |
215 | ||
216 | for (i = 0; i < num_entries; i++) { | |
217 | cur = h + i; | |
218 | INIT_LIST_HEAD(&cur->hash_list); | |
219 | spin_lock_init(&cur->lock); | |
220 | init_waitqueue_head(&cur->wait); | |
221 | } | |
222 | ||
223 | x = cmpxchg(&info->stripe_hash_table, NULL, table); | |
83c8266a DS |
224 | if (x) { |
225 | if (is_vmalloc_addr(x)) | |
226 | vfree(x); | |
227 | else | |
228 | kfree(x); | |
229 | } | |
53b381b3 DW |
230 | return 0; |
231 | } | |
232 | ||
4ae10b3a CM |
233 | /* |
234 | * caching an rbio means to copy anything from the | |
235 | * bio_pages array into the stripe_pages array. We | |
236 | * use the page uptodate bit in the stripe cache array | |
237 | * to indicate if it has valid data | |
238 | * | |
239 | * once the caching is done, we set the cache ready | |
240 | * bit. | |
241 | */ | |
242 | static void cache_rbio_pages(struct btrfs_raid_bio *rbio) | |
243 | { | |
244 | int i; | |
245 | char *s; | |
246 | char *d; | |
247 | int ret; | |
248 | ||
249 | ret = alloc_rbio_pages(rbio); | |
250 | if (ret) | |
251 | return; | |
252 | ||
253 | for (i = 0; i < rbio->nr_pages; i++) { | |
254 | if (!rbio->bio_pages[i]) | |
255 | continue; | |
256 | ||
257 | s = kmap(rbio->bio_pages[i]); | |
258 | d = kmap(rbio->stripe_pages[i]); | |
259 | ||
260 | memcpy(d, s, PAGE_CACHE_SIZE); | |
261 | ||
262 | kunmap(rbio->bio_pages[i]); | |
263 | kunmap(rbio->stripe_pages[i]); | |
264 | SetPageUptodate(rbio->stripe_pages[i]); | |
265 | } | |
266 | set_bit(RBIO_CACHE_READY_BIT, &rbio->flags); | |
267 | } | |
268 | ||
53b381b3 DW |
269 | /* |
270 | * we hash on the first logical address of the stripe | |
271 | */ | |
272 | static int rbio_bucket(struct btrfs_raid_bio *rbio) | |
273 | { | |
274 | u64 num = rbio->raid_map[0]; | |
275 | ||
276 | /* | |
277 | * we shift down quite a bit. We're using byte | |
278 | * addressing, and most of the lower bits are zeros. | |
279 | * This tends to upset hash_64, and it consistently | |
280 | * returns just one or two different values. | |
281 | * | |
282 | * shifting off the lower bits fixes things. | |
283 | */ | |
284 | return hash_64(num >> 16, BTRFS_STRIPE_HASH_TABLE_BITS); | |
285 | } | |
286 | ||
4ae10b3a CM |
287 | /* |
288 | * stealing an rbio means taking all the uptodate pages from the stripe | |
289 | * array in the source rbio and putting them into the destination rbio | |
290 | */ | |
291 | static void steal_rbio(struct btrfs_raid_bio *src, struct btrfs_raid_bio *dest) | |
292 | { | |
293 | int i; | |
294 | struct page *s; | |
295 | struct page *d; | |
296 | ||
297 | if (!test_bit(RBIO_CACHE_READY_BIT, &src->flags)) | |
298 | return; | |
299 | ||
300 | for (i = 0; i < dest->nr_pages; i++) { | |
301 | s = src->stripe_pages[i]; | |
302 | if (!s || !PageUptodate(s)) { | |
303 | continue; | |
304 | } | |
305 | ||
306 | d = dest->stripe_pages[i]; | |
307 | if (d) | |
308 | __free_page(d); | |
309 | ||
310 | dest->stripe_pages[i] = s; | |
311 | src->stripe_pages[i] = NULL; | |
312 | } | |
313 | } | |
314 | ||
53b381b3 DW |
315 | /* |
316 | * merging means we take the bio_list from the victim and | |
317 | * splice it into the destination. The victim should | |
318 | * be discarded afterwards. | |
319 | * | |
320 | * must be called with dest->rbio_list_lock held | |
321 | */ | |
322 | static void merge_rbio(struct btrfs_raid_bio *dest, | |
323 | struct btrfs_raid_bio *victim) | |
324 | { | |
325 | bio_list_merge(&dest->bio_list, &victim->bio_list); | |
326 | dest->bio_list_bytes += victim->bio_list_bytes; | |
327 | bio_list_init(&victim->bio_list); | |
328 | } | |
329 | ||
330 | /* | |
4ae10b3a CM |
331 | * used to prune items that are in the cache. The caller |
332 | * must hold the hash table lock. | |
333 | */ | |
334 | static void __remove_rbio_from_cache(struct btrfs_raid_bio *rbio) | |
335 | { | |
336 | int bucket = rbio_bucket(rbio); | |
337 | struct btrfs_stripe_hash_table *table; | |
338 | struct btrfs_stripe_hash *h; | |
339 | int freeit = 0; | |
340 | ||
341 | /* | |
342 | * check the bit again under the hash table lock. | |
343 | */ | |
344 | if (!test_bit(RBIO_CACHE_BIT, &rbio->flags)) | |
345 | return; | |
346 | ||
347 | table = rbio->fs_info->stripe_hash_table; | |
348 | h = table->table + bucket; | |
349 | ||
350 | /* hold the lock for the bucket because we may be | |
351 | * removing it from the hash table | |
352 | */ | |
353 | spin_lock(&h->lock); | |
354 | ||
355 | /* | |
356 | * hold the lock for the bio list because we need | |
357 | * to make sure the bio list is empty | |
358 | */ | |
359 | spin_lock(&rbio->bio_list_lock); | |
360 | ||
361 | if (test_and_clear_bit(RBIO_CACHE_BIT, &rbio->flags)) { | |
362 | list_del_init(&rbio->stripe_cache); | |
363 | table->cache_size -= 1; | |
364 | freeit = 1; | |
365 | ||
366 | /* if the bio list isn't empty, this rbio is | |
367 | * still involved in an IO. We take it out | |
368 | * of the cache list, and drop the ref that | |
369 | * was held for the list. | |
370 | * | |
371 | * If the bio_list was empty, we also remove | |
372 | * the rbio from the hash_table, and drop | |
373 | * the corresponding ref | |
374 | */ | |
375 | if (bio_list_empty(&rbio->bio_list)) { | |
376 | if (!list_empty(&rbio->hash_list)) { | |
377 | list_del_init(&rbio->hash_list); | |
378 | atomic_dec(&rbio->refs); | |
379 | BUG_ON(!list_empty(&rbio->plug_list)); | |
380 | } | |
381 | } | |
382 | } | |
383 | ||
384 | spin_unlock(&rbio->bio_list_lock); | |
385 | spin_unlock(&h->lock); | |
386 | ||
387 | if (freeit) | |
388 | __free_raid_bio(rbio); | |
389 | } | |
390 | ||
391 | /* | |
392 | * prune a given rbio from the cache | |
393 | */ | |
394 | static void remove_rbio_from_cache(struct btrfs_raid_bio *rbio) | |
395 | { | |
396 | struct btrfs_stripe_hash_table *table; | |
397 | unsigned long flags; | |
398 | ||
399 | if (!test_bit(RBIO_CACHE_BIT, &rbio->flags)) | |
400 | return; | |
401 | ||
402 | table = rbio->fs_info->stripe_hash_table; | |
403 | ||
404 | spin_lock_irqsave(&table->cache_lock, flags); | |
405 | __remove_rbio_from_cache(rbio); | |
406 | spin_unlock_irqrestore(&table->cache_lock, flags); | |
407 | } | |
408 | ||
409 | /* | |
410 | * remove everything in the cache | |
411 | */ | |
48a3b636 | 412 | static void btrfs_clear_rbio_cache(struct btrfs_fs_info *info) |
4ae10b3a CM |
413 | { |
414 | struct btrfs_stripe_hash_table *table; | |
415 | unsigned long flags; | |
416 | struct btrfs_raid_bio *rbio; | |
417 | ||
418 | table = info->stripe_hash_table; | |
419 | ||
420 | spin_lock_irqsave(&table->cache_lock, flags); | |
421 | while (!list_empty(&table->stripe_cache)) { | |
422 | rbio = list_entry(table->stripe_cache.next, | |
423 | struct btrfs_raid_bio, | |
424 | stripe_cache); | |
425 | __remove_rbio_from_cache(rbio); | |
426 | } | |
427 | spin_unlock_irqrestore(&table->cache_lock, flags); | |
428 | } | |
429 | ||
430 | /* | |
431 | * remove all cached entries and free the hash table | |
432 | * used by unmount | |
53b381b3 DW |
433 | */ |
434 | void btrfs_free_stripe_hash_table(struct btrfs_fs_info *info) | |
435 | { | |
436 | if (!info->stripe_hash_table) | |
437 | return; | |
4ae10b3a | 438 | btrfs_clear_rbio_cache(info); |
83c8266a DS |
439 | if (is_vmalloc_addr(info->stripe_hash_table)) |
440 | vfree(info->stripe_hash_table); | |
441 | else | |
442 | kfree(info->stripe_hash_table); | |
53b381b3 DW |
443 | info->stripe_hash_table = NULL; |
444 | } | |
445 | ||
4ae10b3a CM |
446 | /* |
447 | * insert an rbio into the stripe cache. It | |
448 | * must have already been prepared by calling | |
449 | * cache_rbio_pages | |
450 | * | |
451 | * If this rbio was already cached, it gets | |
452 | * moved to the front of the lru. | |
453 | * | |
454 | * If the size of the rbio cache is too big, we | |
455 | * prune an item. | |
456 | */ | |
457 | static void cache_rbio(struct btrfs_raid_bio *rbio) | |
458 | { | |
459 | struct btrfs_stripe_hash_table *table; | |
460 | unsigned long flags; | |
461 | ||
462 | if (!test_bit(RBIO_CACHE_READY_BIT, &rbio->flags)) | |
463 | return; | |
464 | ||
465 | table = rbio->fs_info->stripe_hash_table; | |
466 | ||
467 | spin_lock_irqsave(&table->cache_lock, flags); | |
468 | spin_lock(&rbio->bio_list_lock); | |
469 | ||
470 | /* bump our ref if we were not in the list before */ | |
471 | if (!test_and_set_bit(RBIO_CACHE_BIT, &rbio->flags)) | |
472 | atomic_inc(&rbio->refs); | |
473 | ||
474 | if (!list_empty(&rbio->stripe_cache)){ | |
475 | list_move(&rbio->stripe_cache, &table->stripe_cache); | |
476 | } else { | |
477 | list_add(&rbio->stripe_cache, &table->stripe_cache); | |
478 | table->cache_size += 1; | |
479 | } | |
480 | ||
481 | spin_unlock(&rbio->bio_list_lock); | |
482 | ||
483 | if (table->cache_size > RBIO_CACHE_SIZE) { | |
484 | struct btrfs_raid_bio *found; | |
485 | ||
486 | found = list_entry(table->stripe_cache.prev, | |
487 | struct btrfs_raid_bio, | |
488 | stripe_cache); | |
489 | ||
490 | if (found != rbio) | |
491 | __remove_rbio_from_cache(found); | |
492 | } | |
493 | ||
494 | spin_unlock_irqrestore(&table->cache_lock, flags); | |
495 | return; | |
496 | } | |
497 | ||
53b381b3 DW |
498 | /* |
499 | * helper function to run the xor_blocks api. It is only | |
500 | * able to do MAX_XOR_BLOCKS at a time, so we need to | |
501 | * loop through. | |
502 | */ | |
503 | static void run_xor(void **pages, int src_cnt, ssize_t len) | |
504 | { | |
505 | int src_off = 0; | |
506 | int xor_src_cnt = 0; | |
507 | void *dest = pages[src_cnt]; | |
508 | ||
509 | while(src_cnt > 0) { | |
510 | xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS); | |
511 | xor_blocks(xor_src_cnt, len, dest, pages + src_off); | |
512 | ||
513 | src_cnt -= xor_src_cnt; | |
514 | src_off += xor_src_cnt; | |
515 | } | |
516 | } | |
517 | ||
518 | /* | |
519 | * returns true if the bio list inside this rbio | |
520 | * covers an entire stripe (no rmw required). | |
521 | * Must be called with the bio list lock held, or | |
522 | * at a time when you know it is impossible to add | |
523 | * new bios into the list | |
524 | */ | |
525 | static int __rbio_is_full(struct btrfs_raid_bio *rbio) | |
526 | { | |
527 | unsigned long size = rbio->bio_list_bytes; | |
528 | int ret = 1; | |
529 | ||
530 | if (size != rbio->nr_data * rbio->stripe_len) | |
531 | ret = 0; | |
532 | ||
533 | BUG_ON(size > rbio->nr_data * rbio->stripe_len); | |
534 | return ret; | |
535 | } | |
536 | ||
537 | static int rbio_is_full(struct btrfs_raid_bio *rbio) | |
538 | { | |
539 | unsigned long flags; | |
540 | int ret; | |
541 | ||
542 | spin_lock_irqsave(&rbio->bio_list_lock, flags); | |
543 | ret = __rbio_is_full(rbio); | |
544 | spin_unlock_irqrestore(&rbio->bio_list_lock, flags); | |
545 | return ret; | |
546 | } | |
547 | ||
548 | /* | |
549 | * returns 1 if it is safe to merge two rbios together. | |
550 | * The merging is safe if the two rbios correspond to | |
551 | * the same stripe and if they are both going in the same | |
552 | * direction (read vs write), and if neither one is | |
553 | * locked for final IO | |
554 | * | |
555 | * The caller is responsible for locking such that | |
556 | * rmw_locked is safe to test | |
557 | */ | |
558 | static int rbio_can_merge(struct btrfs_raid_bio *last, | |
559 | struct btrfs_raid_bio *cur) | |
560 | { | |
561 | if (test_bit(RBIO_RMW_LOCKED_BIT, &last->flags) || | |
562 | test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) | |
563 | return 0; | |
564 | ||
4ae10b3a CM |
565 | /* |
566 | * we can't merge with cached rbios, since the | |
567 | * idea is that when we merge the destination | |
568 | * rbio is going to run our IO for us. We can | |
569 | * steal from cached rbio's though, other functions | |
570 | * handle that. | |
571 | */ | |
572 | if (test_bit(RBIO_CACHE_BIT, &last->flags) || | |
573 | test_bit(RBIO_CACHE_BIT, &cur->flags)) | |
574 | return 0; | |
575 | ||
53b381b3 DW |
576 | if (last->raid_map[0] != |
577 | cur->raid_map[0]) | |
578 | return 0; | |
579 | ||
580 | /* reads can't merge with writes */ | |
581 | if (last->read_rebuild != | |
582 | cur->read_rebuild) { | |
583 | return 0; | |
584 | } | |
585 | ||
586 | return 1; | |
587 | } | |
588 | ||
589 | /* | |
590 | * helper to index into the pstripe | |
591 | */ | |
592 | static struct page *rbio_pstripe_page(struct btrfs_raid_bio *rbio, int index) | |
593 | { | |
594 | index += (rbio->nr_data * rbio->stripe_len) >> PAGE_CACHE_SHIFT; | |
595 | return rbio->stripe_pages[index]; | |
596 | } | |
597 | ||
598 | /* | |
599 | * helper to index into the qstripe, returns null | |
600 | * if there is no qstripe | |
601 | */ | |
602 | static struct page *rbio_qstripe_page(struct btrfs_raid_bio *rbio, int index) | |
603 | { | |
604 | if (rbio->nr_data + 1 == rbio->bbio->num_stripes) | |
605 | return NULL; | |
606 | ||
607 | index += ((rbio->nr_data + 1) * rbio->stripe_len) >> | |
608 | PAGE_CACHE_SHIFT; | |
609 | return rbio->stripe_pages[index]; | |
610 | } | |
611 | ||
612 | /* | |
613 | * The first stripe in the table for a logical address | |
614 | * has the lock. rbios are added in one of three ways: | |
615 | * | |
616 | * 1) Nobody has the stripe locked yet. The rbio is given | |
617 | * the lock and 0 is returned. The caller must start the IO | |
618 | * themselves. | |
619 | * | |
620 | * 2) Someone has the stripe locked, but we're able to merge | |
621 | * with the lock owner. The rbio is freed and the IO will | |
622 | * start automatically along with the existing rbio. 1 is returned. | |
623 | * | |
624 | * 3) Someone has the stripe locked, but we're not able to merge. | |
625 | * The rbio is added to the lock owner's plug list, or merged into | |
626 | * an rbio already on the plug list. When the lock owner unlocks, | |
627 | * the next rbio on the list is run and the IO is started automatically. | |
628 | * 1 is returned | |
629 | * | |
630 | * If we return 0, the caller still owns the rbio and must continue with | |
631 | * IO submission. If we return 1, the caller must assume the rbio has | |
632 | * already been freed. | |
633 | */ | |
634 | static noinline int lock_stripe_add(struct btrfs_raid_bio *rbio) | |
635 | { | |
636 | int bucket = rbio_bucket(rbio); | |
637 | struct btrfs_stripe_hash *h = rbio->fs_info->stripe_hash_table->table + bucket; | |
638 | struct btrfs_raid_bio *cur; | |
639 | struct btrfs_raid_bio *pending; | |
640 | unsigned long flags; | |
641 | DEFINE_WAIT(wait); | |
642 | struct btrfs_raid_bio *freeit = NULL; | |
4ae10b3a | 643 | struct btrfs_raid_bio *cache_drop = NULL; |
53b381b3 DW |
644 | int ret = 0; |
645 | int walk = 0; | |
646 | ||
647 | spin_lock_irqsave(&h->lock, flags); | |
648 | list_for_each_entry(cur, &h->hash_list, hash_list) { | |
649 | walk++; | |
650 | if (cur->raid_map[0] == rbio->raid_map[0]) { | |
651 | spin_lock(&cur->bio_list_lock); | |
652 | ||
4ae10b3a CM |
653 | /* can we steal this cached rbio's pages? */ |
654 | if (bio_list_empty(&cur->bio_list) && | |
655 | list_empty(&cur->plug_list) && | |
656 | test_bit(RBIO_CACHE_BIT, &cur->flags) && | |
657 | !test_bit(RBIO_RMW_LOCKED_BIT, &cur->flags)) { | |
658 | list_del_init(&cur->hash_list); | |
659 | atomic_dec(&cur->refs); | |
660 | ||
661 | steal_rbio(cur, rbio); | |
662 | cache_drop = cur; | |
663 | spin_unlock(&cur->bio_list_lock); | |
664 | ||
665 | goto lockit; | |
666 | } | |
667 | ||
53b381b3 DW |
668 | /* can we merge into the lock owner? */ |
669 | if (rbio_can_merge(cur, rbio)) { | |
670 | merge_rbio(cur, rbio); | |
671 | spin_unlock(&cur->bio_list_lock); | |
672 | freeit = rbio; | |
673 | ret = 1; | |
674 | goto out; | |
675 | } | |
676 | ||
4ae10b3a | 677 | |
53b381b3 DW |
678 | /* |
679 | * we couldn't merge with the running | |
680 | * rbio, see if we can merge with the | |
681 | * pending ones. We don't have to | |
682 | * check for rmw_locked because there | |
683 | * is no way they are inside finish_rmw | |
684 | * right now | |
685 | */ | |
686 | list_for_each_entry(pending, &cur->plug_list, | |
687 | plug_list) { | |
688 | if (rbio_can_merge(pending, rbio)) { | |
689 | merge_rbio(pending, rbio); | |
690 | spin_unlock(&cur->bio_list_lock); | |
691 | freeit = rbio; | |
692 | ret = 1; | |
693 | goto out; | |
694 | } | |
695 | } | |
696 | ||
697 | /* no merging, put us on the tail of the plug list, | |
698 | * our rbio will be started with the currently | |
699 | * running rbio unlocks | |
700 | */ | |
701 | list_add_tail(&rbio->plug_list, &cur->plug_list); | |
702 | spin_unlock(&cur->bio_list_lock); | |
703 | ret = 1; | |
704 | goto out; | |
705 | } | |
706 | } | |
4ae10b3a | 707 | lockit: |
53b381b3 DW |
708 | atomic_inc(&rbio->refs); |
709 | list_add(&rbio->hash_list, &h->hash_list); | |
710 | out: | |
711 | spin_unlock_irqrestore(&h->lock, flags); | |
4ae10b3a CM |
712 | if (cache_drop) |
713 | remove_rbio_from_cache(cache_drop); | |
53b381b3 DW |
714 | if (freeit) |
715 | __free_raid_bio(freeit); | |
716 | return ret; | |
717 | } | |
718 | ||
719 | /* | |
720 | * called as rmw or parity rebuild is completed. If the plug list has more | |
721 | * rbios waiting for this stripe, the next one on the list will be started | |
722 | */ | |
723 | static noinline void unlock_stripe(struct btrfs_raid_bio *rbio) | |
724 | { | |
725 | int bucket; | |
726 | struct btrfs_stripe_hash *h; | |
727 | unsigned long flags; | |
4ae10b3a | 728 | int keep_cache = 0; |
53b381b3 DW |
729 | |
730 | bucket = rbio_bucket(rbio); | |
731 | h = rbio->fs_info->stripe_hash_table->table + bucket; | |
732 | ||
4ae10b3a CM |
733 | if (list_empty(&rbio->plug_list)) |
734 | cache_rbio(rbio); | |
735 | ||
53b381b3 DW |
736 | spin_lock_irqsave(&h->lock, flags); |
737 | spin_lock(&rbio->bio_list_lock); | |
738 | ||
739 | if (!list_empty(&rbio->hash_list)) { | |
4ae10b3a CM |
740 | /* |
741 | * if we're still cached and there is no other IO | |
742 | * to perform, just leave this rbio here for others | |
743 | * to steal from later | |
744 | */ | |
745 | if (list_empty(&rbio->plug_list) && | |
746 | test_bit(RBIO_CACHE_BIT, &rbio->flags)) { | |
747 | keep_cache = 1; | |
748 | clear_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags); | |
749 | BUG_ON(!bio_list_empty(&rbio->bio_list)); | |
750 | goto done; | |
751 | } | |
53b381b3 DW |
752 | |
753 | list_del_init(&rbio->hash_list); | |
754 | atomic_dec(&rbio->refs); | |
755 | ||
756 | /* | |
757 | * we use the plug list to hold all the rbios | |
758 | * waiting for the chance to lock this stripe. | |
759 | * hand the lock over to one of them. | |
760 | */ | |
761 | if (!list_empty(&rbio->plug_list)) { | |
762 | struct btrfs_raid_bio *next; | |
763 | struct list_head *head = rbio->plug_list.next; | |
764 | ||
765 | next = list_entry(head, struct btrfs_raid_bio, | |
766 | plug_list); | |
767 | ||
768 | list_del_init(&rbio->plug_list); | |
769 | ||
770 | list_add(&next->hash_list, &h->hash_list); | |
771 | atomic_inc(&next->refs); | |
772 | spin_unlock(&rbio->bio_list_lock); | |
773 | spin_unlock_irqrestore(&h->lock, flags); | |
774 | ||
775 | if (next->read_rebuild) | |
776 | async_read_rebuild(next); | |
4ae10b3a CM |
777 | else { |
778 | steal_rbio(rbio, next); | |
53b381b3 | 779 | async_rmw_stripe(next); |
4ae10b3a | 780 | } |
53b381b3 DW |
781 | |
782 | goto done_nolock; | |
53b381b3 DW |
783 | } else if (waitqueue_active(&h->wait)) { |
784 | spin_unlock(&rbio->bio_list_lock); | |
785 | spin_unlock_irqrestore(&h->lock, flags); | |
786 | wake_up(&h->wait); | |
787 | goto done_nolock; | |
788 | } | |
789 | } | |
4ae10b3a | 790 | done: |
53b381b3 DW |
791 | spin_unlock(&rbio->bio_list_lock); |
792 | spin_unlock_irqrestore(&h->lock, flags); | |
793 | ||
794 | done_nolock: | |
4ae10b3a CM |
795 | if (!keep_cache) |
796 | remove_rbio_from_cache(rbio); | |
53b381b3 DW |
797 | } |
798 | ||
799 | static void __free_raid_bio(struct btrfs_raid_bio *rbio) | |
800 | { | |
801 | int i; | |
802 | ||
803 | WARN_ON(atomic_read(&rbio->refs) < 0); | |
804 | if (!atomic_dec_and_test(&rbio->refs)) | |
805 | return; | |
806 | ||
4ae10b3a | 807 | WARN_ON(!list_empty(&rbio->stripe_cache)); |
53b381b3 DW |
808 | WARN_ON(!list_empty(&rbio->hash_list)); |
809 | WARN_ON(!bio_list_empty(&rbio->bio_list)); | |
810 | ||
811 | for (i = 0; i < rbio->nr_pages; i++) { | |
812 | if (rbio->stripe_pages[i]) { | |
813 | __free_page(rbio->stripe_pages[i]); | |
814 | rbio->stripe_pages[i] = NULL; | |
815 | } | |
816 | } | |
817 | kfree(rbio->raid_map); | |
818 | kfree(rbio->bbio); | |
819 | kfree(rbio); | |
820 | } | |
821 | ||
822 | static void free_raid_bio(struct btrfs_raid_bio *rbio) | |
823 | { | |
824 | unlock_stripe(rbio); | |
825 | __free_raid_bio(rbio); | |
826 | } | |
827 | ||
828 | /* | |
829 | * this frees the rbio and runs through all the bios in the | |
830 | * bio_list and calls end_io on them | |
831 | */ | |
832 | static void rbio_orig_end_io(struct btrfs_raid_bio *rbio, int err, int uptodate) | |
833 | { | |
834 | struct bio *cur = bio_list_get(&rbio->bio_list); | |
835 | struct bio *next; | |
836 | free_raid_bio(rbio); | |
837 | ||
838 | while (cur) { | |
839 | next = cur->bi_next; | |
840 | cur->bi_next = NULL; | |
841 | if (uptodate) | |
842 | set_bit(BIO_UPTODATE, &cur->bi_flags); | |
843 | bio_endio(cur, err); | |
844 | cur = next; | |
845 | } | |
846 | } | |
847 | ||
848 | /* | |
849 | * end io function used by finish_rmw. When we finally | |
850 | * get here, we've written a full stripe | |
851 | */ | |
852 | static void raid_write_end_io(struct bio *bio, int err) | |
853 | { | |
854 | struct btrfs_raid_bio *rbio = bio->bi_private; | |
855 | ||
856 | if (err) | |
857 | fail_bio_stripe(rbio, bio); | |
858 | ||
859 | bio_put(bio); | |
860 | ||
861 | if (!atomic_dec_and_test(&rbio->bbio->stripes_pending)) | |
862 | return; | |
863 | ||
864 | err = 0; | |
865 | ||
866 | /* OK, we have read all the stripes we need to. */ | |
867 | if (atomic_read(&rbio->bbio->error) > rbio->bbio->max_errors) | |
868 | err = -EIO; | |
869 | ||
870 | rbio_orig_end_io(rbio, err, 0); | |
871 | return; | |
872 | } | |
873 | ||
874 | /* | |
875 | * the read/modify/write code wants to use the original bio for | |
876 | * any pages it included, and then use the rbio for everything | |
877 | * else. This function decides if a given index (stripe number) | |
878 | * and page number in that stripe fall inside the original bio | |
879 | * or the rbio. | |
880 | * | |
881 | * if you set bio_list_only, you'll get a NULL back for any ranges | |
882 | * that are outside the bio_list | |
883 | * | |
884 | * This doesn't take any refs on anything, you get a bare page pointer | |
885 | * and the caller must bump refs as required. | |
886 | * | |
887 | * You must call index_rbio_pages once before you can trust | |
888 | * the answers from this function. | |
889 | */ | |
890 | static struct page *page_in_rbio(struct btrfs_raid_bio *rbio, | |
891 | int index, int pagenr, int bio_list_only) | |
892 | { | |
893 | int chunk_page; | |
894 | struct page *p = NULL; | |
895 | ||
896 | chunk_page = index * (rbio->stripe_len >> PAGE_SHIFT) + pagenr; | |
897 | ||
898 | spin_lock_irq(&rbio->bio_list_lock); | |
899 | p = rbio->bio_pages[chunk_page]; | |
900 | spin_unlock_irq(&rbio->bio_list_lock); | |
901 | ||
902 | if (p || bio_list_only) | |
903 | return p; | |
904 | ||
905 | return rbio->stripe_pages[chunk_page]; | |
906 | } | |
907 | ||
908 | /* | |
909 | * number of pages we need for the entire stripe across all the | |
910 | * drives | |
911 | */ | |
912 | static unsigned long rbio_nr_pages(unsigned long stripe_len, int nr_stripes) | |
913 | { | |
914 | unsigned long nr = stripe_len * nr_stripes; | |
915 | return (nr + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
916 | } | |
917 | ||
918 | /* | |
919 | * allocation and initial setup for the btrfs_raid_bio. Not | |
920 | * this does not allocate any pages for rbio->pages. | |
921 | */ | |
922 | static struct btrfs_raid_bio *alloc_rbio(struct btrfs_root *root, | |
923 | struct btrfs_bio *bbio, u64 *raid_map, | |
924 | u64 stripe_len) | |
925 | { | |
926 | struct btrfs_raid_bio *rbio; | |
927 | int nr_data = 0; | |
928 | int num_pages = rbio_nr_pages(stripe_len, bbio->num_stripes); | |
929 | void *p; | |
930 | ||
931 | rbio = kzalloc(sizeof(*rbio) + num_pages * sizeof(struct page *) * 2, | |
932 | GFP_NOFS); | |
933 | if (!rbio) { | |
934 | kfree(raid_map); | |
935 | kfree(bbio); | |
936 | return ERR_PTR(-ENOMEM); | |
937 | } | |
938 | ||
939 | bio_list_init(&rbio->bio_list); | |
940 | INIT_LIST_HEAD(&rbio->plug_list); | |
941 | spin_lock_init(&rbio->bio_list_lock); | |
4ae10b3a | 942 | INIT_LIST_HEAD(&rbio->stripe_cache); |
53b381b3 DW |
943 | INIT_LIST_HEAD(&rbio->hash_list); |
944 | rbio->bbio = bbio; | |
945 | rbio->raid_map = raid_map; | |
946 | rbio->fs_info = root->fs_info; | |
947 | rbio->stripe_len = stripe_len; | |
948 | rbio->nr_pages = num_pages; | |
949 | rbio->faila = -1; | |
950 | rbio->failb = -1; | |
951 | atomic_set(&rbio->refs, 1); | |
952 | ||
953 | /* | |
954 | * the stripe_pages and bio_pages array point to the extra | |
955 | * memory we allocated past the end of the rbio | |
956 | */ | |
957 | p = rbio + 1; | |
958 | rbio->stripe_pages = p; | |
959 | rbio->bio_pages = p + sizeof(struct page *) * num_pages; | |
960 | ||
961 | if (raid_map[bbio->num_stripes - 1] == RAID6_Q_STRIPE) | |
962 | nr_data = bbio->num_stripes - 2; | |
963 | else | |
964 | nr_data = bbio->num_stripes - 1; | |
965 | ||
966 | rbio->nr_data = nr_data; | |
967 | return rbio; | |
968 | } | |
969 | ||
970 | /* allocate pages for all the stripes in the bio, including parity */ | |
971 | static int alloc_rbio_pages(struct btrfs_raid_bio *rbio) | |
972 | { | |
973 | int i; | |
974 | struct page *page; | |
975 | ||
976 | for (i = 0; i < rbio->nr_pages; i++) { | |
977 | if (rbio->stripe_pages[i]) | |
978 | continue; | |
979 | page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); | |
980 | if (!page) | |
981 | return -ENOMEM; | |
982 | rbio->stripe_pages[i] = page; | |
983 | ClearPageUptodate(page); | |
984 | } | |
985 | return 0; | |
986 | } | |
987 | ||
988 | /* allocate pages for just the p/q stripes */ | |
989 | static int alloc_rbio_parity_pages(struct btrfs_raid_bio *rbio) | |
990 | { | |
991 | int i; | |
992 | struct page *page; | |
993 | ||
994 | i = (rbio->nr_data * rbio->stripe_len) >> PAGE_CACHE_SHIFT; | |
995 | ||
996 | for (; i < rbio->nr_pages; i++) { | |
997 | if (rbio->stripe_pages[i]) | |
998 | continue; | |
999 | page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); | |
1000 | if (!page) | |
1001 | return -ENOMEM; | |
1002 | rbio->stripe_pages[i] = page; | |
1003 | } | |
1004 | return 0; | |
1005 | } | |
1006 | ||
1007 | /* | |
1008 | * add a single page from a specific stripe into our list of bios for IO | |
1009 | * this will try to merge into existing bios if possible, and returns | |
1010 | * zero if all went well. | |
1011 | */ | |
48a3b636 ES |
1012 | static int rbio_add_io_page(struct btrfs_raid_bio *rbio, |
1013 | struct bio_list *bio_list, | |
1014 | struct page *page, | |
1015 | int stripe_nr, | |
1016 | unsigned long page_index, | |
1017 | unsigned long bio_max_len) | |
53b381b3 DW |
1018 | { |
1019 | struct bio *last = bio_list->tail; | |
1020 | u64 last_end = 0; | |
1021 | int ret; | |
1022 | struct bio *bio; | |
1023 | struct btrfs_bio_stripe *stripe; | |
1024 | u64 disk_start; | |
1025 | ||
1026 | stripe = &rbio->bbio->stripes[stripe_nr]; | |
1027 | disk_start = stripe->physical + (page_index << PAGE_CACHE_SHIFT); | |
1028 | ||
1029 | /* if the device is missing, just fail this stripe */ | |
1030 | if (!stripe->dev->bdev) | |
1031 | return fail_rbio_index(rbio, stripe_nr); | |
1032 | ||
1033 | /* see if we can add this page onto our existing bio */ | |
1034 | if (last) { | |
1035 | last_end = (u64)last->bi_sector << 9; | |
1036 | last_end += last->bi_size; | |
1037 | ||
1038 | /* | |
1039 | * we can't merge these if they are from different | |
1040 | * devices or if they are not contiguous | |
1041 | */ | |
1042 | if (last_end == disk_start && stripe->dev->bdev && | |
1043 | test_bit(BIO_UPTODATE, &last->bi_flags) && | |
1044 | last->bi_bdev == stripe->dev->bdev) { | |
1045 | ret = bio_add_page(last, page, PAGE_CACHE_SIZE, 0); | |
1046 | if (ret == PAGE_CACHE_SIZE) | |
1047 | return 0; | |
1048 | } | |
1049 | } | |
1050 | ||
1051 | /* put a new bio on the list */ | |
9be3395b | 1052 | bio = btrfs_io_bio_alloc(GFP_NOFS, bio_max_len >> PAGE_SHIFT?:1); |
53b381b3 DW |
1053 | if (!bio) |
1054 | return -ENOMEM; | |
1055 | ||
1056 | bio->bi_size = 0; | |
1057 | bio->bi_bdev = stripe->dev->bdev; | |
1058 | bio->bi_sector = disk_start >> 9; | |
1059 | set_bit(BIO_UPTODATE, &bio->bi_flags); | |
1060 | ||
1061 | bio_add_page(bio, page, PAGE_CACHE_SIZE, 0); | |
1062 | bio_list_add(bio_list, bio); | |
1063 | return 0; | |
1064 | } | |
1065 | ||
1066 | /* | |
1067 | * while we're doing the read/modify/write cycle, we could | |
1068 | * have errors in reading pages off the disk. This checks | |
1069 | * for errors and if we're not able to read the page it'll | |
1070 | * trigger parity reconstruction. The rmw will be finished | |
1071 | * after we've reconstructed the failed stripes | |
1072 | */ | |
1073 | static void validate_rbio_for_rmw(struct btrfs_raid_bio *rbio) | |
1074 | { | |
1075 | if (rbio->faila >= 0 || rbio->failb >= 0) { | |
1076 | BUG_ON(rbio->faila == rbio->bbio->num_stripes - 1); | |
1077 | __raid56_parity_recover(rbio); | |
1078 | } else { | |
1079 | finish_rmw(rbio); | |
1080 | } | |
1081 | } | |
1082 | ||
1083 | /* | |
1084 | * these are just the pages from the rbio array, not from anything | |
1085 | * the FS sent down to us | |
1086 | */ | |
1087 | static struct page *rbio_stripe_page(struct btrfs_raid_bio *rbio, int stripe, int page) | |
1088 | { | |
1089 | int index; | |
1090 | index = stripe * (rbio->stripe_len >> PAGE_CACHE_SHIFT); | |
1091 | index += page; | |
1092 | return rbio->stripe_pages[index]; | |
1093 | } | |
1094 | ||
1095 | /* | |
1096 | * helper function to walk our bio list and populate the bio_pages array with | |
1097 | * the result. This seems expensive, but it is faster than constantly | |
1098 | * searching through the bio list as we setup the IO in finish_rmw or stripe | |
1099 | * reconstruction. | |
1100 | * | |
1101 | * This must be called before you trust the answers from page_in_rbio | |
1102 | */ | |
1103 | static void index_rbio_pages(struct btrfs_raid_bio *rbio) | |
1104 | { | |
1105 | struct bio *bio; | |
1106 | u64 start; | |
1107 | unsigned long stripe_offset; | |
1108 | unsigned long page_index; | |
1109 | struct page *p; | |
1110 | int i; | |
1111 | ||
1112 | spin_lock_irq(&rbio->bio_list_lock); | |
1113 | bio_list_for_each(bio, &rbio->bio_list) { | |
1114 | start = (u64)bio->bi_sector << 9; | |
1115 | stripe_offset = start - rbio->raid_map[0]; | |
1116 | page_index = stripe_offset >> PAGE_CACHE_SHIFT; | |
1117 | ||
1118 | for (i = 0; i < bio->bi_vcnt; i++) { | |
1119 | p = bio->bi_io_vec[i].bv_page; | |
1120 | rbio->bio_pages[page_index + i] = p; | |
1121 | } | |
1122 | } | |
1123 | spin_unlock_irq(&rbio->bio_list_lock); | |
1124 | } | |
1125 | ||
1126 | /* | |
1127 | * this is called from one of two situations. We either | |
1128 | * have a full stripe from the higher layers, or we've read all | |
1129 | * the missing bits off disk. | |
1130 | * | |
1131 | * This will calculate the parity and then send down any | |
1132 | * changed blocks. | |
1133 | */ | |
1134 | static noinline void finish_rmw(struct btrfs_raid_bio *rbio) | |
1135 | { | |
1136 | struct btrfs_bio *bbio = rbio->bbio; | |
1137 | void *pointers[bbio->num_stripes]; | |
1138 | int stripe_len = rbio->stripe_len; | |
1139 | int nr_data = rbio->nr_data; | |
1140 | int stripe; | |
1141 | int pagenr; | |
1142 | int p_stripe = -1; | |
1143 | int q_stripe = -1; | |
1144 | struct bio_list bio_list; | |
1145 | struct bio *bio; | |
1146 | int pages_per_stripe = stripe_len >> PAGE_CACHE_SHIFT; | |
1147 | int ret; | |
1148 | ||
1149 | bio_list_init(&bio_list); | |
1150 | ||
1151 | if (bbio->num_stripes - rbio->nr_data == 1) { | |
1152 | p_stripe = bbio->num_stripes - 1; | |
1153 | } else if (bbio->num_stripes - rbio->nr_data == 2) { | |
1154 | p_stripe = bbio->num_stripes - 2; | |
1155 | q_stripe = bbio->num_stripes - 1; | |
1156 | } else { | |
1157 | BUG(); | |
1158 | } | |
1159 | ||
1160 | /* at this point we either have a full stripe, | |
1161 | * or we've read the full stripe from the drive. | |
1162 | * recalculate the parity and write the new results. | |
1163 | * | |
1164 | * We're not allowed to add any new bios to the | |
1165 | * bio list here, anyone else that wants to | |
1166 | * change this stripe needs to do their own rmw. | |
1167 | */ | |
1168 | spin_lock_irq(&rbio->bio_list_lock); | |
1169 | set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags); | |
1170 | spin_unlock_irq(&rbio->bio_list_lock); | |
1171 | ||
1172 | atomic_set(&rbio->bbio->error, 0); | |
1173 | ||
1174 | /* | |
1175 | * now that we've set rmw_locked, run through the | |
1176 | * bio list one last time and map the page pointers | |
4ae10b3a CM |
1177 | * |
1178 | * We don't cache full rbios because we're assuming | |
1179 | * the higher layers are unlikely to use this area of | |
1180 | * the disk again soon. If they do use it again, | |
1181 | * hopefully they will send another full bio. | |
53b381b3 DW |
1182 | */ |
1183 | index_rbio_pages(rbio); | |
4ae10b3a CM |
1184 | if (!rbio_is_full(rbio)) |
1185 | cache_rbio_pages(rbio); | |
1186 | else | |
1187 | clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags); | |
53b381b3 DW |
1188 | |
1189 | for (pagenr = 0; pagenr < pages_per_stripe; pagenr++) { | |
1190 | struct page *p; | |
1191 | /* first collect one page from each data stripe */ | |
1192 | for (stripe = 0; stripe < nr_data; stripe++) { | |
1193 | p = page_in_rbio(rbio, stripe, pagenr, 0); | |
1194 | pointers[stripe] = kmap(p); | |
1195 | } | |
1196 | ||
1197 | /* then add the parity stripe */ | |
1198 | p = rbio_pstripe_page(rbio, pagenr); | |
1199 | SetPageUptodate(p); | |
1200 | pointers[stripe++] = kmap(p); | |
1201 | ||
1202 | if (q_stripe != -1) { | |
1203 | ||
1204 | /* | |
1205 | * raid6, add the qstripe and call the | |
1206 | * library function to fill in our p/q | |
1207 | */ | |
1208 | p = rbio_qstripe_page(rbio, pagenr); | |
1209 | SetPageUptodate(p); | |
1210 | pointers[stripe++] = kmap(p); | |
1211 | ||
1212 | raid6_call.gen_syndrome(bbio->num_stripes, PAGE_SIZE, | |
1213 | pointers); | |
1214 | } else { | |
1215 | /* raid5 */ | |
1216 | memcpy(pointers[nr_data], pointers[0], PAGE_SIZE); | |
1217 | run_xor(pointers + 1, nr_data - 1, PAGE_CACHE_SIZE); | |
1218 | } | |
1219 | ||
1220 | ||
1221 | for (stripe = 0; stripe < bbio->num_stripes; stripe++) | |
1222 | kunmap(page_in_rbio(rbio, stripe, pagenr, 0)); | |
1223 | } | |
1224 | ||
1225 | /* | |
1226 | * time to start writing. Make bios for everything from the | |
1227 | * higher layers (the bio_list in our rbio) and our p/q. Ignore | |
1228 | * everything else. | |
1229 | */ | |
1230 | for (stripe = 0; stripe < bbio->num_stripes; stripe++) { | |
1231 | for (pagenr = 0; pagenr < pages_per_stripe; pagenr++) { | |
1232 | struct page *page; | |
1233 | if (stripe < rbio->nr_data) { | |
1234 | page = page_in_rbio(rbio, stripe, pagenr, 1); | |
1235 | if (!page) | |
1236 | continue; | |
1237 | } else { | |
1238 | page = rbio_stripe_page(rbio, stripe, pagenr); | |
1239 | } | |
1240 | ||
1241 | ret = rbio_add_io_page(rbio, &bio_list, | |
1242 | page, stripe, pagenr, rbio->stripe_len); | |
1243 | if (ret) | |
1244 | goto cleanup; | |
1245 | } | |
1246 | } | |
1247 | ||
1248 | atomic_set(&bbio->stripes_pending, bio_list_size(&bio_list)); | |
1249 | BUG_ON(atomic_read(&bbio->stripes_pending) == 0); | |
1250 | ||
1251 | while (1) { | |
1252 | bio = bio_list_pop(&bio_list); | |
1253 | if (!bio) | |
1254 | break; | |
1255 | ||
1256 | bio->bi_private = rbio; | |
1257 | bio->bi_end_io = raid_write_end_io; | |
1258 | BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags)); | |
1259 | submit_bio(WRITE, bio); | |
1260 | } | |
1261 | return; | |
1262 | ||
1263 | cleanup: | |
1264 | rbio_orig_end_io(rbio, -EIO, 0); | |
1265 | } | |
1266 | ||
1267 | /* | |
1268 | * helper to find the stripe number for a given bio. Used to figure out which | |
1269 | * stripe has failed. This expects the bio to correspond to a physical disk, | |
1270 | * so it looks up based on physical sector numbers. | |
1271 | */ | |
1272 | static int find_bio_stripe(struct btrfs_raid_bio *rbio, | |
1273 | struct bio *bio) | |
1274 | { | |
1275 | u64 physical = bio->bi_sector; | |
1276 | u64 stripe_start; | |
1277 | int i; | |
1278 | struct btrfs_bio_stripe *stripe; | |
1279 | ||
1280 | physical <<= 9; | |
1281 | ||
1282 | for (i = 0; i < rbio->bbio->num_stripes; i++) { | |
1283 | stripe = &rbio->bbio->stripes[i]; | |
1284 | stripe_start = stripe->physical; | |
1285 | if (physical >= stripe_start && | |
1286 | physical < stripe_start + rbio->stripe_len) { | |
1287 | return i; | |
1288 | } | |
1289 | } | |
1290 | return -1; | |
1291 | } | |
1292 | ||
1293 | /* | |
1294 | * helper to find the stripe number for a given | |
1295 | * bio (before mapping). Used to figure out which stripe has | |
1296 | * failed. This looks up based on logical block numbers. | |
1297 | */ | |
1298 | static int find_logical_bio_stripe(struct btrfs_raid_bio *rbio, | |
1299 | struct bio *bio) | |
1300 | { | |
1301 | u64 logical = bio->bi_sector; | |
1302 | u64 stripe_start; | |
1303 | int i; | |
1304 | ||
1305 | logical <<= 9; | |
1306 | ||
1307 | for (i = 0; i < rbio->nr_data; i++) { | |
1308 | stripe_start = rbio->raid_map[i]; | |
1309 | if (logical >= stripe_start && | |
1310 | logical < stripe_start + rbio->stripe_len) { | |
1311 | return i; | |
1312 | } | |
1313 | } | |
1314 | return -1; | |
1315 | } | |
1316 | ||
1317 | /* | |
1318 | * returns -EIO if we had too many failures | |
1319 | */ | |
1320 | static int fail_rbio_index(struct btrfs_raid_bio *rbio, int failed) | |
1321 | { | |
1322 | unsigned long flags; | |
1323 | int ret = 0; | |
1324 | ||
1325 | spin_lock_irqsave(&rbio->bio_list_lock, flags); | |
1326 | ||
1327 | /* we already know this stripe is bad, move on */ | |
1328 | if (rbio->faila == failed || rbio->failb == failed) | |
1329 | goto out; | |
1330 | ||
1331 | if (rbio->faila == -1) { | |
1332 | /* first failure on this rbio */ | |
1333 | rbio->faila = failed; | |
1334 | atomic_inc(&rbio->bbio->error); | |
1335 | } else if (rbio->failb == -1) { | |
1336 | /* second failure on this rbio */ | |
1337 | rbio->failb = failed; | |
1338 | atomic_inc(&rbio->bbio->error); | |
1339 | } else { | |
1340 | ret = -EIO; | |
1341 | } | |
1342 | out: | |
1343 | spin_unlock_irqrestore(&rbio->bio_list_lock, flags); | |
1344 | ||
1345 | return ret; | |
1346 | } | |
1347 | ||
1348 | /* | |
1349 | * helper to fail a stripe based on a physical disk | |
1350 | * bio. | |
1351 | */ | |
1352 | static int fail_bio_stripe(struct btrfs_raid_bio *rbio, | |
1353 | struct bio *bio) | |
1354 | { | |
1355 | int failed = find_bio_stripe(rbio, bio); | |
1356 | ||
1357 | if (failed < 0) | |
1358 | return -EIO; | |
1359 | ||
1360 | return fail_rbio_index(rbio, failed); | |
1361 | } | |
1362 | ||
1363 | /* | |
1364 | * this sets each page in the bio uptodate. It should only be used on private | |
1365 | * rbio pages, nothing that comes in from the higher layers | |
1366 | */ | |
1367 | static void set_bio_pages_uptodate(struct bio *bio) | |
1368 | { | |
1369 | int i; | |
1370 | struct page *p; | |
1371 | ||
1372 | for (i = 0; i < bio->bi_vcnt; i++) { | |
1373 | p = bio->bi_io_vec[i].bv_page; | |
1374 | SetPageUptodate(p); | |
1375 | } | |
1376 | } | |
1377 | ||
1378 | /* | |
1379 | * end io for the read phase of the rmw cycle. All the bios here are physical | |
1380 | * stripe bios we've read from the disk so we can recalculate the parity of the | |
1381 | * stripe. | |
1382 | * | |
1383 | * This will usually kick off finish_rmw once all the bios are read in, but it | |
1384 | * may trigger parity reconstruction if we had any errors along the way | |
1385 | */ | |
1386 | static void raid_rmw_end_io(struct bio *bio, int err) | |
1387 | { | |
1388 | struct btrfs_raid_bio *rbio = bio->bi_private; | |
1389 | ||
1390 | if (err) | |
1391 | fail_bio_stripe(rbio, bio); | |
1392 | else | |
1393 | set_bio_pages_uptodate(bio); | |
1394 | ||
1395 | bio_put(bio); | |
1396 | ||
1397 | if (!atomic_dec_and_test(&rbio->bbio->stripes_pending)) | |
1398 | return; | |
1399 | ||
1400 | err = 0; | |
1401 | if (atomic_read(&rbio->bbio->error) > rbio->bbio->max_errors) | |
1402 | goto cleanup; | |
1403 | ||
1404 | /* | |
1405 | * this will normally call finish_rmw to start our write | |
1406 | * but if there are any failed stripes we'll reconstruct | |
1407 | * from parity first | |
1408 | */ | |
1409 | validate_rbio_for_rmw(rbio); | |
1410 | return; | |
1411 | ||
1412 | cleanup: | |
1413 | ||
1414 | rbio_orig_end_io(rbio, -EIO, 0); | |
1415 | } | |
1416 | ||
1417 | static void async_rmw_stripe(struct btrfs_raid_bio *rbio) | |
1418 | { | |
1419 | rbio->work.flags = 0; | |
1420 | rbio->work.func = rmw_work; | |
1421 | ||
1422 | btrfs_queue_worker(&rbio->fs_info->rmw_workers, | |
1423 | &rbio->work); | |
1424 | } | |
1425 | ||
1426 | static void async_read_rebuild(struct btrfs_raid_bio *rbio) | |
1427 | { | |
1428 | rbio->work.flags = 0; | |
1429 | rbio->work.func = read_rebuild_work; | |
1430 | ||
1431 | btrfs_queue_worker(&rbio->fs_info->rmw_workers, | |
1432 | &rbio->work); | |
1433 | } | |
1434 | ||
1435 | /* | |
1436 | * the stripe must be locked by the caller. It will | |
1437 | * unlock after all the writes are done | |
1438 | */ | |
1439 | static int raid56_rmw_stripe(struct btrfs_raid_bio *rbio) | |
1440 | { | |
1441 | int bios_to_read = 0; | |
1442 | struct btrfs_bio *bbio = rbio->bbio; | |
1443 | struct bio_list bio_list; | |
1444 | int ret; | |
1445 | int nr_pages = (rbio->stripe_len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
1446 | int pagenr; | |
1447 | int stripe; | |
1448 | struct bio *bio; | |
1449 | ||
1450 | bio_list_init(&bio_list); | |
1451 | ||
1452 | ret = alloc_rbio_pages(rbio); | |
1453 | if (ret) | |
1454 | goto cleanup; | |
1455 | ||
1456 | index_rbio_pages(rbio); | |
1457 | ||
1458 | atomic_set(&rbio->bbio->error, 0); | |
1459 | /* | |
1460 | * build a list of bios to read all the missing parts of this | |
1461 | * stripe | |
1462 | */ | |
1463 | for (stripe = 0; stripe < rbio->nr_data; stripe++) { | |
1464 | for (pagenr = 0; pagenr < nr_pages; pagenr++) { | |
1465 | struct page *page; | |
1466 | /* | |
1467 | * we want to find all the pages missing from | |
1468 | * the rbio and read them from the disk. If | |
1469 | * page_in_rbio finds a page in the bio list | |
1470 | * we don't need to read it off the stripe. | |
1471 | */ | |
1472 | page = page_in_rbio(rbio, stripe, pagenr, 1); | |
1473 | if (page) | |
1474 | continue; | |
1475 | ||
1476 | page = rbio_stripe_page(rbio, stripe, pagenr); | |
4ae10b3a CM |
1477 | /* |
1478 | * the bio cache may have handed us an uptodate | |
1479 | * page. If so, be happy and use it | |
1480 | */ | |
1481 | if (PageUptodate(page)) | |
1482 | continue; | |
1483 | ||
53b381b3 DW |
1484 | ret = rbio_add_io_page(rbio, &bio_list, page, |
1485 | stripe, pagenr, rbio->stripe_len); | |
1486 | if (ret) | |
1487 | goto cleanup; | |
1488 | } | |
1489 | } | |
1490 | ||
1491 | bios_to_read = bio_list_size(&bio_list); | |
1492 | if (!bios_to_read) { | |
1493 | /* | |
1494 | * this can happen if others have merged with | |
1495 | * us, it means there is nothing left to read. | |
1496 | * But if there are missing devices it may not be | |
1497 | * safe to do the full stripe write yet. | |
1498 | */ | |
1499 | goto finish; | |
1500 | } | |
1501 | ||
1502 | /* | |
1503 | * the bbio may be freed once we submit the last bio. Make sure | |
1504 | * not to touch it after that | |
1505 | */ | |
1506 | atomic_set(&bbio->stripes_pending, bios_to_read); | |
1507 | while (1) { | |
1508 | bio = bio_list_pop(&bio_list); | |
1509 | if (!bio) | |
1510 | break; | |
1511 | ||
1512 | bio->bi_private = rbio; | |
1513 | bio->bi_end_io = raid_rmw_end_io; | |
1514 | ||
1515 | btrfs_bio_wq_end_io(rbio->fs_info, bio, | |
1516 | BTRFS_WQ_ENDIO_RAID56); | |
1517 | ||
1518 | BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags)); | |
1519 | submit_bio(READ, bio); | |
1520 | } | |
1521 | /* the actual write will happen once the reads are done */ | |
1522 | return 0; | |
1523 | ||
1524 | cleanup: | |
1525 | rbio_orig_end_io(rbio, -EIO, 0); | |
1526 | return -EIO; | |
1527 | ||
1528 | finish: | |
1529 | validate_rbio_for_rmw(rbio); | |
1530 | return 0; | |
1531 | } | |
1532 | ||
1533 | /* | |
1534 | * if the upper layers pass in a full stripe, we thank them by only allocating | |
1535 | * enough pages to hold the parity, and sending it all down quickly. | |
1536 | */ | |
1537 | static int full_stripe_write(struct btrfs_raid_bio *rbio) | |
1538 | { | |
1539 | int ret; | |
1540 | ||
1541 | ret = alloc_rbio_parity_pages(rbio); | |
3cd846d1 MX |
1542 | if (ret) { |
1543 | __free_raid_bio(rbio); | |
53b381b3 | 1544 | return ret; |
3cd846d1 | 1545 | } |
53b381b3 DW |
1546 | |
1547 | ret = lock_stripe_add(rbio); | |
1548 | if (ret == 0) | |
1549 | finish_rmw(rbio); | |
1550 | return 0; | |
1551 | } | |
1552 | ||
1553 | /* | |
1554 | * partial stripe writes get handed over to async helpers. | |
1555 | * We're really hoping to merge a few more writes into this | |
1556 | * rbio before calculating new parity | |
1557 | */ | |
1558 | static int partial_stripe_write(struct btrfs_raid_bio *rbio) | |
1559 | { | |
1560 | int ret; | |
1561 | ||
1562 | ret = lock_stripe_add(rbio); | |
1563 | if (ret == 0) | |
1564 | async_rmw_stripe(rbio); | |
1565 | return 0; | |
1566 | } | |
1567 | ||
1568 | /* | |
1569 | * sometimes while we were reading from the drive to | |
1570 | * recalculate parity, enough new bios come into create | |
1571 | * a full stripe. So we do a check here to see if we can | |
1572 | * go directly to finish_rmw | |
1573 | */ | |
1574 | static int __raid56_parity_write(struct btrfs_raid_bio *rbio) | |
1575 | { | |
1576 | /* head off into rmw land if we don't have a full stripe */ | |
1577 | if (!rbio_is_full(rbio)) | |
1578 | return partial_stripe_write(rbio); | |
1579 | return full_stripe_write(rbio); | |
1580 | } | |
1581 | ||
6ac0f488 CM |
1582 | /* |
1583 | * We use plugging call backs to collect full stripes. | |
1584 | * Any time we get a partial stripe write while plugged | |
1585 | * we collect it into a list. When the unplug comes down, | |
1586 | * we sort the list by logical block number and merge | |
1587 | * everything we can into the same rbios | |
1588 | */ | |
1589 | struct btrfs_plug_cb { | |
1590 | struct blk_plug_cb cb; | |
1591 | struct btrfs_fs_info *info; | |
1592 | struct list_head rbio_list; | |
1593 | struct btrfs_work work; | |
1594 | }; | |
1595 | ||
1596 | /* | |
1597 | * rbios on the plug list are sorted for easier merging. | |
1598 | */ | |
1599 | static int plug_cmp(void *priv, struct list_head *a, struct list_head *b) | |
1600 | { | |
1601 | struct btrfs_raid_bio *ra = container_of(a, struct btrfs_raid_bio, | |
1602 | plug_list); | |
1603 | struct btrfs_raid_bio *rb = container_of(b, struct btrfs_raid_bio, | |
1604 | plug_list); | |
1605 | u64 a_sector = ra->bio_list.head->bi_sector; | |
1606 | u64 b_sector = rb->bio_list.head->bi_sector; | |
1607 | ||
1608 | if (a_sector < b_sector) | |
1609 | return -1; | |
1610 | if (a_sector > b_sector) | |
1611 | return 1; | |
1612 | return 0; | |
1613 | } | |
1614 | ||
1615 | static void run_plug(struct btrfs_plug_cb *plug) | |
1616 | { | |
1617 | struct btrfs_raid_bio *cur; | |
1618 | struct btrfs_raid_bio *last = NULL; | |
1619 | ||
1620 | /* | |
1621 | * sort our plug list then try to merge | |
1622 | * everything we can in hopes of creating full | |
1623 | * stripes. | |
1624 | */ | |
1625 | list_sort(NULL, &plug->rbio_list, plug_cmp); | |
1626 | while (!list_empty(&plug->rbio_list)) { | |
1627 | cur = list_entry(plug->rbio_list.next, | |
1628 | struct btrfs_raid_bio, plug_list); | |
1629 | list_del_init(&cur->plug_list); | |
1630 | ||
1631 | if (rbio_is_full(cur)) { | |
1632 | /* we have a full stripe, send it down */ | |
1633 | full_stripe_write(cur); | |
1634 | continue; | |
1635 | } | |
1636 | if (last) { | |
1637 | if (rbio_can_merge(last, cur)) { | |
1638 | merge_rbio(last, cur); | |
1639 | __free_raid_bio(cur); | |
1640 | continue; | |
1641 | ||
1642 | } | |
1643 | __raid56_parity_write(last); | |
1644 | } | |
1645 | last = cur; | |
1646 | } | |
1647 | if (last) { | |
1648 | __raid56_parity_write(last); | |
1649 | } | |
1650 | kfree(plug); | |
1651 | } | |
1652 | ||
1653 | /* | |
1654 | * if the unplug comes from schedule, we have to push the | |
1655 | * work off to a helper thread | |
1656 | */ | |
1657 | static void unplug_work(struct btrfs_work *work) | |
1658 | { | |
1659 | struct btrfs_plug_cb *plug; | |
1660 | plug = container_of(work, struct btrfs_plug_cb, work); | |
1661 | run_plug(plug); | |
1662 | } | |
1663 | ||
1664 | static void btrfs_raid_unplug(struct blk_plug_cb *cb, bool from_schedule) | |
1665 | { | |
1666 | struct btrfs_plug_cb *plug; | |
1667 | plug = container_of(cb, struct btrfs_plug_cb, cb); | |
1668 | ||
1669 | if (from_schedule) { | |
1670 | plug->work.flags = 0; | |
1671 | plug->work.func = unplug_work; | |
1672 | btrfs_queue_worker(&plug->info->rmw_workers, | |
1673 | &plug->work); | |
1674 | return; | |
1675 | } | |
1676 | run_plug(plug); | |
1677 | } | |
1678 | ||
53b381b3 DW |
1679 | /* |
1680 | * our main entry point for writes from the rest of the FS. | |
1681 | */ | |
1682 | int raid56_parity_write(struct btrfs_root *root, struct bio *bio, | |
1683 | struct btrfs_bio *bbio, u64 *raid_map, | |
1684 | u64 stripe_len) | |
1685 | { | |
1686 | struct btrfs_raid_bio *rbio; | |
6ac0f488 CM |
1687 | struct btrfs_plug_cb *plug = NULL; |
1688 | struct blk_plug_cb *cb; | |
53b381b3 DW |
1689 | |
1690 | rbio = alloc_rbio(root, bbio, raid_map, stripe_len); | |
3dc0e818 | 1691 | if (IS_ERR(rbio)) |
53b381b3 | 1692 | return PTR_ERR(rbio); |
53b381b3 DW |
1693 | bio_list_add(&rbio->bio_list, bio); |
1694 | rbio->bio_list_bytes = bio->bi_size; | |
6ac0f488 CM |
1695 | |
1696 | /* | |
1697 | * don't plug on full rbios, just get them out the door | |
1698 | * as quickly as we can | |
1699 | */ | |
1700 | if (rbio_is_full(rbio)) | |
1701 | return full_stripe_write(rbio); | |
1702 | ||
1703 | cb = blk_check_plugged(btrfs_raid_unplug, root->fs_info, | |
1704 | sizeof(*plug)); | |
1705 | if (cb) { | |
1706 | plug = container_of(cb, struct btrfs_plug_cb, cb); | |
1707 | if (!plug->info) { | |
1708 | plug->info = root->fs_info; | |
1709 | INIT_LIST_HEAD(&plug->rbio_list); | |
1710 | } | |
1711 | list_add_tail(&rbio->plug_list, &plug->rbio_list); | |
1712 | } else { | |
1713 | return __raid56_parity_write(rbio); | |
1714 | } | |
1715 | return 0; | |
53b381b3 DW |
1716 | } |
1717 | ||
1718 | /* | |
1719 | * all parity reconstruction happens here. We've read in everything | |
1720 | * we can find from the drives and this does the heavy lifting of | |
1721 | * sorting the good from the bad. | |
1722 | */ | |
1723 | static void __raid_recover_end_io(struct btrfs_raid_bio *rbio) | |
1724 | { | |
1725 | int pagenr, stripe; | |
1726 | void **pointers; | |
1727 | int faila = -1, failb = -1; | |
1728 | int nr_pages = (rbio->stripe_len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
1729 | struct page *page; | |
1730 | int err; | |
1731 | int i; | |
1732 | ||
1733 | pointers = kzalloc(rbio->bbio->num_stripes * sizeof(void *), | |
1734 | GFP_NOFS); | |
1735 | if (!pointers) { | |
1736 | err = -ENOMEM; | |
1737 | goto cleanup_io; | |
1738 | } | |
1739 | ||
1740 | faila = rbio->faila; | |
1741 | failb = rbio->failb; | |
1742 | ||
1743 | if (rbio->read_rebuild) { | |
1744 | spin_lock_irq(&rbio->bio_list_lock); | |
1745 | set_bit(RBIO_RMW_LOCKED_BIT, &rbio->flags); | |
1746 | spin_unlock_irq(&rbio->bio_list_lock); | |
1747 | } | |
1748 | ||
1749 | index_rbio_pages(rbio); | |
1750 | ||
1751 | for (pagenr = 0; pagenr < nr_pages; pagenr++) { | |
1752 | /* setup our array of pointers with pages | |
1753 | * from each stripe | |
1754 | */ | |
1755 | for (stripe = 0; stripe < rbio->bbio->num_stripes; stripe++) { | |
1756 | /* | |
1757 | * if we're rebuilding a read, we have to use | |
1758 | * pages from the bio list | |
1759 | */ | |
1760 | if (rbio->read_rebuild && | |
1761 | (stripe == faila || stripe == failb)) { | |
1762 | page = page_in_rbio(rbio, stripe, pagenr, 0); | |
1763 | } else { | |
1764 | page = rbio_stripe_page(rbio, stripe, pagenr); | |
1765 | } | |
1766 | pointers[stripe] = kmap(page); | |
1767 | } | |
1768 | ||
1769 | /* all raid6 handling here */ | |
1770 | if (rbio->raid_map[rbio->bbio->num_stripes - 1] == | |
1771 | RAID6_Q_STRIPE) { | |
1772 | ||
1773 | /* | |
1774 | * single failure, rebuild from parity raid5 | |
1775 | * style | |
1776 | */ | |
1777 | if (failb < 0) { | |
1778 | if (faila == rbio->nr_data) { | |
1779 | /* | |
1780 | * Just the P stripe has failed, without | |
1781 | * a bad data or Q stripe. | |
1782 | * TODO, we should redo the xor here. | |
1783 | */ | |
1784 | err = -EIO; | |
1785 | goto cleanup; | |
1786 | } | |
1787 | /* | |
1788 | * a single failure in raid6 is rebuilt | |
1789 | * in the pstripe code below | |
1790 | */ | |
1791 | goto pstripe; | |
1792 | } | |
1793 | ||
1794 | /* make sure our ps and qs are in order */ | |
1795 | if (faila > failb) { | |
1796 | int tmp = failb; | |
1797 | failb = faila; | |
1798 | faila = tmp; | |
1799 | } | |
1800 | ||
1801 | /* if the q stripe is failed, do a pstripe reconstruction | |
1802 | * from the xors. | |
1803 | * If both the q stripe and the P stripe are failed, we're | |
1804 | * here due to a crc mismatch and we can't give them the | |
1805 | * data they want | |
1806 | */ | |
1807 | if (rbio->raid_map[failb] == RAID6_Q_STRIPE) { | |
1808 | if (rbio->raid_map[faila] == RAID5_P_STRIPE) { | |
1809 | err = -EIO; | |
1810 | goto cleanup; | |
1811 | } | |
1812 | /* | |
1813 | * otherwise we have one bad data stripe and | |
1814 | * a good P stripe. raid5! | |
1815 | */ | |
1816 | goto pstripe; | |
1817 | } | |
1818 | ||
1819 | if (rbio->raid_map[failb] == RAID5_P_STRIPE) { | |
1820 | raid6_datap_recov(rbio->bbio->num_stripes, | |
1821 | PAGE_SIZE, faila, pointers); | |
1822 | } else { | |
1823 | raid6_2data_recov(rbio->bbio->num_stripes, | |
1824 | PAGE_SIZE, faila, failb, | |
1825 | pointers); | |
1826 | } | |
1827 | } else { | |
1828 | void *p; | |
1829 | ||
1830 | /* rebuild from P stripe here (raid5 or raid6) */ | |
1831 | BUG_ON(failb != -1); | |
1832 | pstripe: | |
1833 | /* Copy parity block into failed block to start with */ | |
1834 | memcpy(pointers[faila], | |
1835 | pointers[rbio->nr_data], | |
1836 | PAGE_CACHE_SIZE); | |
1837 | ||
1838 | /* rearrange the pointer array */ | |
1839 | p = pointers[faila]; | |
1840 | for (stripe = faila; stripe < rbio->nr_data - 1; stripe++) | |
1841 | pointers[stripe] = pointers[stripe + 1]; | |
1842 | pointers[rbio->nr_data - 1] = p; | |
1843 | ||
1844 | /* xor in the rest */ | |
1845 | run_xor(pointers, rbio->nr_data - 1, PAGE_CACHE_SIZE); | |
1846 | } | |
1847 | /* if we're doing this rebuild as part of an rmw, go through | |
1848 | * and set all of our private rbio pages in the | |
1849 | * failed stripes as uptodate. This way finish_rmw will | |
1850 | * know they can be trusted. If this was a read reconstruction, | |
1851 | * other endio functions will fiddle the uptodate bits | |
1852 | */ | |
1853 | if (!rbio->read_rebuild) { | |
1854 | for (i = 0; i < nr_pages; i++) { | |
1855 | if (faila != -1) { | |
1856 | page = rbio_stripe_page(rbio, faila, i); | |
1857 | SetPageUptodate(page); | |
1858 | } | |
1859 | if (failb != -1) { | |
1860 | page = rbio_stripe_page(rbio, failb, i); | |
1861 | SetPageUptodate(page); | |
1862 | } | |
1863 | } | |
1864 | } | |
1865 | for (stripe = 0; stripe < rbio->bbio->num_stripes; stripe++) { | |
1866 | /* | |
1867 | * if we're rebuilding a read, we have to use | |
1868 | * pages from the bio list | |
1869 | */ | |
1870 | if (rbio->read_rebuild && | |
1871 | (stripe == faila || stripe == failb)) { | |
1872 | page = page_in_rbio(rbio, stripe, pagenr, 0); | |
1873 | } else { | |
1874 | page = rbio_stripe_page(rbio, stripe, pagenr); | |
1875 | } | |
1876 | kunmap(page); | |
1877 | } | |
1878 | } | |
1879 | ||
1880 | err = 0; | |
1881 | cleanup: | |
1882 | kfree(pointers); | |
1883 | ||
1884 | cleanup_io: | |
1885 | ||
1886 | if (rbio->read_rebuild) { | |
4ae10b3a CM |
1887 | if (err == 0) |
1888 | cache_rbio_pages(rbio); | |
1889 | else | |
1890 | clear_bit(RBIO_CACHE_READY_BIT, &rbio->flags); | |
1891 | ||
53b381b3 DW |
1892 | rbio_orig_end_io(rbio, err, err == 0); |
1893 | } else if (err == 0) { | |
1894 | rbio->faila = -1; | |
1895 | rbio->failb = -1; | |
1896 | finish_rmw(rbio); | |
1897 | } else { | |
1898 | rbio_orig_end_io(rbio, err, 0); | |
1899 | } | |
1900 | } | |
1901 | ||
1902 | /* | |
1903 | * This is called only for stripes we've read from disk to | |
1904 | * reconstruct the parity. | |
1905 | */ | |
1906 | static void raid_recover_end_io(struct bio *bio, int err) | |
1907 | { | |
1908 | struct btrfs_raid_bio *rbio = bio->bi_private; | |
1909 | ||
1910 | /* | |
1911 | * we only read stripe pages off the disk, set them | |
1912 | * up to date if there were no errors | |
1913 | */ | |
1914 | if (err) | |
1915 | fail_bio_stripe(rbio, bio); | |
1916 | else | |
1917 | set_bio_pages_uptodate(bio); | |
1918 | bio_put(bio); | |
1919 | ||
1920 | if (!atomic_dec_and_test(&rbio->bbio->stripes_pending)) | |
1921 | return; | |
1922 | ||
1923 | if (atomic_read(&rbio->bbio->error) > rbio->bbio->max_errors) | |
1924 | rbio_orig_end_io(rbio, -EIO, 0); | |
1925 | else | |
1926 | __raid_recover_end_io(rbio); | |
1927 | } | |
1928 | ||
1929 | /* | |
1930 | * reads everything we need off the disk to reconstruct | |
1931 | * the parity. endio handlers trigger final reconstruction | |
1932 | * when the IO is done. | |
1933 | * | |
1934 | * This is used both for reads from the higher layers and for | |
1935 | * parity construction required to finish a rmw cycle. | |
1936 | */ | |
1937 | static int __raid56_parity_recover(struct btrfs_raid_bio *rbio) | |
1938 | { | |
1939 | int bios_to_read = 0; | |
1940 | struct btrfs_bio *bbio = rbio->bbio; | |
1941 | struct bio_list bio_list; | |
1942 | int ret; | |
1943 | int nr_pages = (rbio->stripe_len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
1944 | int pagenr; | |
1945 | int stripe; | |
1946 | struct bio *bio; | |
1947 | ||
1948 | bio_list_init(&bio_list); | |
1949 | ||
1950 | ret = alloc_rbio_pages(rbio); | |
1951 | if (ret) | |
1952 | goto cleanup; | |
1953 | ||
1954 | atomic_set(&rbio->bbio->error, 0); | |
1955 | ||
1956 | /* | |
4ae10b3a CM |
1957 | * read everything that hasn't failed. Thanks to the |
1958 | * stripe cache, it is possible that some or all of these | |
1959 | * pages are going to be uptodate. | |
53b381b3 DW |
1960 | */ |
1961 | for (stripe = 0; stripe < bbio->num_stripes; stripe++) { | |
1962 | if (rbio->faila == stripe || | |
1963 | rbio->failb == stripe) | |
1964 | continue; | |
1965 | ||
1966 | for (pagenr = 0; pagenr < nr_pages; pagenr++) { | |
1967 | struct page *p; | |
1968 | ||
1969 | /* | |
1970 | * the rmw code may have already read this | |
1971 | * page in | |
1972 | */ | |
1973 | p = rbio_stripe_page(rbio, stripe, pagenr); | |
1974 | if (PageUptodate(p)) | |
1975 | continue; | |
1976 | ||
1977 | ret = rbio_add_io_page(rbio, &bio_list, | |
1978 | rbio_stripe_page(rbio, stripe, pagenr), | |
1979 | stripe, pagenr, rbio->stripe_len); | |
1980 | if (ret < 0) | |
1981 | goto cleanup; | |
1982 | } | |
1983 | } | |
1984 | ||
1985 | bios_to_read = bio_list_size(&bio_list); | |
1986 | if (!bios_to_read) { | |
1987 | /* | |
1988 | * we might have no bios to read just because the pages | |
1989 | * were up to date, or we might have no bios to read because | |
1990 | * the devices were gone. | |
1991 | */ | |
1992 | if (atomic_read(&rbio->bbio->error) <= rbio->bbio->max_errors) { | |
1993 | __raid_recover_end_io(rbio); | |
1994 | goto out; | |
1995 | } else { | |
1996 | goto cleanup; | |
1997 | } | |
1998 | } | |
1999 | ||
2000 | /* | |
2001 | * the bbio may be freed once we submit the last bio. Make sure | |
2002 | * not to touch it after that | |
2003 | */ | |
2004 | atomic_set(&bbio->stripes_pending, bios_to_read); | |
2005 | while (1) { | |
2006 | bio = bio_list_pop(&bio_list); | |
2007 | if (!bio) | |
2008 | break; | |
2009 | ||
2010 | bio->bi_private = rbio; | |
2011 | bio->bi_end_io = raid_recover_end_io; | |
2012 | ||
2013 | btrfs_bio_wq_end_io(rbio->fs_info, bio, | |
2014 | BTRFS_WQ_ENDIO_RAID56); | |
2015 | ||
2016 | BUG_ON(!test_bit(BIO_UPTODATE, &bio->bi_flags)); | |
2017 | submit_bio(READ, bio); | |
2018 | } | |
2019 | out: | |
2020 | return 0; | |
2021 | ||
2022 | cleanup: | |
2023 | if (rbio->read_rebuild) | |
2024 | rbio_orig_end_io(rbio, -EIO, 0); | |
2025 | return -EIO; | |
2026 | } | |
2027 | ||
2028 | /* | |
2029 | * the main entry point for reads from the higher layers. This | |
2030 | * is really only called when the normal read path had a failure, | |
2031 | * so we assume the bio they send down corresponds to a failed part | |
2032 | * of the drive. | |
2033 | */ | |
2034 | int raid56_parity_recover(struct btrfs_root *root, struct bio *bio, | |
2035 | struct btrfs_bio *bbio, u64 *raid_map, | |
2036 | u64 stripe_len, int mirror_num) | |
2037 | { | |
2038 | struct btrfs_raid_bio *rbio; | |
2039 | int ret; | |
2040 | ||
2041 | rbio = alloc_rbio(root, bbio, raid_map, stripe_len); | |
3dc0e818 | 2042 | if (IS_ERR(rbio)) |
53b381b3 | 2043 | return PTR_ERR(rbio); |
53b381b3 DW |
2044 | |
2045 | rbio->read_rebuild = 1; | |
2046 | bio_list_add(&rbio->bio_list, bio); | |
2047 | rbio->bio_list_bytes = bio->bi_size; | |
2048 | ||
2049 | rbio->faila = find_logical_bio_stripe(rbio, bio); | |
2050 | if (rbio->faila == -1) { | |
2051 | BUG(); | |
3dc0e818 DC |
2052 | kfree(raid_map); |
2053 | kfree(bbio); | |
53b381b3 DW |
2054 | kfree(rbio); |
2055 | return -EIO; | |
2056 | } | |
2057 | ||
2058 | /* | |
2059 | * reconstruct from the q stripe if they are | |
2060 | * asking for mirror 3 | |
2061 | */ | |
2062 | if (mirror_num == 3) | |
2063 | rbio->failb = bbio->num_stripes - 2; | |
2064 | ||
2065 | ret = lock_stripe_add(rbio); | |
2066 | ||
2067 | /* | |
2068 | * __raid56_parity_recover will end the bio with | |
2069 | * any errors it hits. We don't want to return | |
2070 | * its error value up the stack because our caller | |
2071 | * will end up calling bio_endio with any nonzero | |
2072 | * return | |
2073 | */ | |
2074 | if (ret == 0) | |
2075 | __raid56_parity_recover(rbio); | |
2076 | /* | |
2077 | * our rbio has been added to the list of | |
2078 | * rbios that will be handled after the | |
2079 | * currently lock owner is done | |
2080 | */ | |
2081 | return 0; | |
2082 | ||
2083 | } | |
2084 | ||
2085 | static void rmw_work(struct btrfs_work *work) | |
2086 | { | |
2087 | struct btrfs_raid_bio *rbio; | |
2088 | ||
2089 | rbio = container_of(work, struct btrfs_raid_bio, work); | |
2090 | raid56_rmw_stripe(rbio); | |
2091 | } | |
2092 | ||
2093 | static void read_rebuild_work(struct btrfs_work *work) | |
2094 | { | |
2095 | struct btrfs_raid_bio *rbio; | |
2096 | ||
2097 | rbio = container_of(work, struct btrfs_raid_bio, work); | |
2098 | __raid56_parity_recover(rbio); | |
2099 | } |