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raid5-cache: free I/O units earlier
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1/*
2 * Copyright (C) 2015 Shaohua Li <shli@fb.com>
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms and conditions of the GNU General Public License,
6 * version 2, as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
11 * more details.
12 *
13 */
14#include <linux/kernel.h>
15#include <linux/wait.h>
16#include <linux/blkdev.h>
17#include <linux/slab.h>
18#include <linux/raid/md_p.h>
5cb2fbd6 19#include <linux/crc32c.h>
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20#include <linux/random.h>
21#include "md.h"
22#include "raid5.h"
23
24/*
25 * metadata/data stored in disk with 4k size unit (a block) regardless
26 * underneath hardware sector size. only works with PAGE_SIZE == 4096
27 */
28#define BLOCK_SECTORS (8)
29
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30/*
31 * reclaim runs every 1/4 disk size or 10G reclaimable space. This can prevent
32 * recovery scans a very long log
33 */
34#define RECLAIM_MAX_FREE_SPACE (10 * 1024 * 1024 * 2) /* sector */
35#define RECLAIM_MAX_FREE_SPACE_SHIFT (2)
36
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37struct r5l_log {
38 struct md_rdev *rdev;
39
40 u32 uuid_checksum;
41
42 sector_t device_size; /* log device size, round to
43 * BLOCK_SECTORS */
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44 sector_t max_free_space; /* reclaim run if free space is at
45 * this size */
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46
47 sector_t last_checkpoint; /* log tail. where recovery scan
48 * starts from */
49 u64 last_cp_seq; /* log tail sequence */
50
51 sector_t log_start; /* log head. where new data appends */
52 u64 seq; /* log head sequence */
53
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54 sector_t next_checkpoint;
55 u64 next_cp_seq;
56
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57 struct mutex io_mutex;
58 struct r5l_io_unit *current_io; /* current io_unit accepting new data */
59
60 spinlock_t io_list_lock;
61 struct list_head running_ios; /* io_units which are still running,
62 * and have not yet been completely
63 * written to the log */
64 struct list_head io_end_ios; /* io_units which have been completely
65 * written to the log but not yet written
66 * to the RAID */
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67 struct list_head flushing_ios; /* io_units which are waiting for log
68 * cache flush */
69 struct list_head flushed_ios; /* io_units which settle down in log disk */
70 struct bio flush_bio;
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71
72 struct kmem_cache *io_kc;
73
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74 struct md_thread *reclaim_thread;
75 unsigned long reclaim_target; /* number of space that need to be
76 * reclaimed. if it's 0, reclaim spaces
77 * used by io_units which are in
78 * IO_UNIT_STRIPE_END state (eg, reclaim
79 * dones't wait for specific io_unit
80 * switching to IO_UNIT_STRIPE_END
81 * state) */
0fd22b45 82 wait_queue_head_t iounit_wait;
0576b1c6 83
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84 struct list_head no_space_stripes; /* pending stripes, log has no space */
85 spinlock_t no_space_stripes_lock;
86};
87
88/*
89 * an IO range starts from a meta data block and end at the next meta data
90 * block. The io unit's the meta data block tracks data/parity followed it. io
91 * unit is written to log disk with normal write, as we always flush log disk
92 * first and then start move data to raid disks, there is no requirement to
93 * write io unit with FLUSH/FUA
94 */
95struct r5l_io_unit {
96 struct r5l_log *log;
97
98 struct page *meta_page; /* store meta block */
99 int meta_offset; /* current offset in meta_page */
100
101 struct bio_list bios;
102 atomic_t pending_io; /* pending bios not written to log yet */
103 struct bio *current_bio;/* current_bio accepting new data */
104
105 atomic_t pending_stripe;/* how many stripes not flushed to raid */
106 u64 seq; /* seq number of the metablock */
107 sector_t log_start; /* where the io_unit starts */
108 sector_t log_end; /* where the io_unit ends */
109 struct list_head log_sibling; /* log->running_ios */
110 struct list_head stripe_list; /* stripes added to the io_unit */
111
112 int state;
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113};
114
115/* r5l_io_unit state */
116enum r5l_io_unit_state {
117 IO_UNIT_RUNNING = 0, /* accepting new IO */
118 IO_UNIT_IO_START = 1, /* io_unit bio start writing to log,
119 * don't accepting new bio */
120 IO_UNIT_IO_END = 2, /* io_unit bio finish writing to log */
a8c34f91 121 IO_UNIT_STRIPE_END = 3, /* stripes data finished writing to raid */
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122};
123
124static sector_t r5l_ring_add(struct r5l_log *log, sector_t start, sector_t inc)
125{
126 start += inc;
127 if (start >= log->device_size)
128 start = start - log->device_size;
129 return start;
130}
131
132static sector_t r5l_ring_distance(struct r5l_log *log, sector_t start,
133 sector_t end)
134{
135 if (end >= start)
136 return end - start;
137 else
138 return end + log->device_size - start;
139}
140
141static bool r5l_has_free_space(struct r5l_log *log, sector_t size)
142{
143 sector_t used_size;
144
145 used_size = r5l_ring_distance(log, log->last_checkpoint,
146 log->log_start);
147
148 return log->device_size > used_size + size;
149}
150
151static struct r5l_io_unit *r5l_alloc_io_unit(struct r5l_log *log)
152{
153 struct r5l_io_unit *io;
154 /* We can't handle memory allocate failure so far */
155 gfp_t gfp = GFP_NOIO | __GFP_NOFAIL;
156
157 io = kmem_cache_zalloc(log->io_kc, gfp);
158 io->log = log;
159 io->meta_page = alloc_page(gfp | __GFP_ZERO);
160
161 bio_list_init(&io->bios);
162 INIT_LIST_HEAD(&io->log_sibling);
163 INIT_LIST_HEAD(&io->stripe_list);
164 io->state = IO_UNIT_RUNNING;
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165 return io;
166}
167
168static void r5l_free_io_unit(struct r5l_log *log, struct r5l_io_unit *io)
169{
170 __free_page(io->meta_page);
171 kmem_cache_free(log->io_kc, io);
172}
173
174static void r5l_move_io_unit_list(struct list_head *from, struct list_head *to,
175 enum r5l_io_unit_state state)
176{
177 struct r5l_io_unit *io;
178
179 while (!list_empty(from)) {
180 io = list_first_entry(from, struct r5l_io_unit, log_sibling);
181 /* don't change list order */
182 if (io->state >= state)
183 list_move_tail(&io->log_sibling, to);
184 else
185 break;
186 }
187}
188
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189static void __r5l_set_io_unit_state(struct r5l_io_unit *io,
190 enum r5l_io_unit_state state)
191{
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192 if (WARN_ON(io->state >= state))
193 return;
194 io->state = state;
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195}
196
197/* XXX: totally ignores I/O errors */
198static void r5l_log_endio(struct bio *bio)
199{
200 struct r5l_io_unit *io = bio->bi_private;
201 struct r5l_log *log = io->log;
509ffec7 202 unsigned long flags;
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203
204 bio_put(bio);
205
206 if (!atomic_dec_and_test(&io->pending_io))
207 return;
208
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209 spin_lock_irqsave(&log->io_list_lock, flags);
210 __r5l_set_io_unit_state(io, IO_UNIT_IO_END);
211 r5l_move_io_unit_list(&log->running_ios, &log->io_end_ios,
212 IO_UNIT_IO_END);
213 spin_unlock_irqrestore(&log->io_list_lock, flags);
214
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215 md_wakeup_thread(log->rdev->mddev->thread);
216}
217
218static void r5l_submit_current_io(struct r5l_log *log)
219{
220 struct r5l_io_unit *io = log->current_io;
221 struct r5l_meta_block *block;
222 struct bio *bio;
509ffec7 223 unsigned long flags;
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224 u32 crc;
225
226 if (!io)
227 return;
228
229 block = page_address(io->meta_page);
230 block->meta_size = cpu_to_le32(io->meta_offset);
5cb2fbd6 231 crc = crc32c_le(log->uuid_checksum, block, PAGE_SIZE);
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232 block->checksum = cpu_to_le32(crc);
233
234 log->current_io = NULL;
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235 spin_lock_irqsave(&log->io_list_lock, flags);
236 __r5l_set_io_unit_state(io, IO_UNIT_IO_START);
237 spin_unlock_irqrestore(&log->io_list_lock, flags);
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238
239 while ((bio = bio_list_pop(&io->bios))) {
240 /* all IO must start from rdev->data_offset */
241 bio->bi_iter.bi_sector += log->rdev->data_offset;
242 submit_bio(WRITE, bio);
243 }
244}
245
246static struct r5l_io_unit *r5l_new_meta(struct r5l_log *log)
247{
248 struct r5l_io_unit *io;
249 struct r5l_meta_block *block;
250 struct bio *bio;
251
252 io = r5l_alloc_io_unit(log);
253
254 block = page_address(io->meta_page);
255 block->magic = cpu_to_le32(R5LOG_MAGIC);
256 block->version = R5LOG_VERSION;
257 block->seq = cpu_to_le64(log->seq);
258 block->position = cpu_to_le64(log->log_start);
259
260 io->log_start = log->log_start;
261 io->meta_offset = sizeof(struct r5l_meta_block);
262 io->seq = log->seq;
263
264 bio = bio_kmalloc(GFP_NOIO | __GFP_NOFAIL, BIO_MAX_PAGES);
265 io->current_bio = bio;
266 bio->bi_rw = WRITE;
267 bio->bi_bdev = log->rdev->bdev;
268 bio->bi_iter.bi_sector = log->log_start;
269 bio_add_page(bio, io->meta_page, PAGE_SIZE, 0);
270 bio->bi_end_io = r5l_log_endio;
271 bio->bi_private = io;
272
273 bio_list_add(&io->bios, bio);
274 atomic_inc(&io->pending_io);
275
276 log->seq++;
277 log->log_start = r5l_ring_add(log, log->log_start, BLOCK_SECTORS);
278 io->log_end = log->log_start;
279 /* current bio hit disk end */
280 if (log->log_start == 0)
281 io->current_bio = NULL;
282
283 spin_lock_irq(&log->io_list_lock);
284 list_add_tail(&io->log_sibling, &log->running_ios);
285 spin_unlock_irq(&log->io_list_lock);
286
287 return io;
288}
289
290static int r5l_get_meta(struct r5l_log *log, unsigned int payload_size)
291{
292 struct r5l_io_unit *io;
293
294 io = log->current_io;
295 if (io && io->meta_offset + payload_size > PAGE_SIZE)
296 r5l_submit_current_io(log);
297 io = log->current_io;
298 if (io)
299 return 0;
300
301 log->current_io = r5l_new_meta(log);
302 return 0;
303}
304
305static void r5l_append_payload_meta(struct r5l_log *log, u16 type,
306 sector_t location,
307 u32 checksum1, u32 checksum2,
308 bool checksum2_valid)
309{
310 struct r5l_io_unit *io = log->current_io;
311 struct r5l_payload_data_parity *payload;
312
313 payload = page_address(io->meta_page) + io->meta_offset;
314 payload->header.type = cpu_to_le16(type);
315 payload->header.flags = cpu_to_le16(0);
316 payload->size = cpu_to_le32((1 + !!checksum2_valid) <<
317 (PAGE_SHIFT - 9));
318 payload->location = cpu_to_le64(location);
319 payload->checksum[0] = cpu_to_le32(checksum1);
320 if (checksum2_valid)
321 payload->checksum[1] = cpu_to_le32(checksum2);
322
323 io->meta_offset += sizeof(struct r5l_payload_data_parity) +
324 sizeof(__le32) * (1 + !!checksum2_valid);
325}
326
327static void r5l_append_payload_page(struct r5l_log *log, struct page *page)
328{
329 struct r5l_io_unit *io = log->current_io;
330
331alloc_bio:
332 if (!io->current_bio) {
333 struct bio *bio;
334
335 bio = bio_kmalloc(GFP_NOIO | __GFP_NOFAIL, BIO_MAX_PAGES);
336 bio->bi_rw = WRITE;
337 bio->bi_bdev = log->rdev->bdev;
338 bio->bi_iter.bi_sector = log->log_start;
339 bio->bi_end_io = r5l_log_endio;
340 bio->bi_private = io;
341 bio_list_add(&io->bios, bio);
342 atomic_inc(&io->pending_io);
343 io->current_bio = bio;
344 }
345 if (!bio_add_page(io->current_bio, page, PAGE_SIZE, 0)) {
346 io->current_bio = NULL;
347 goto alloc_bio;
348 }
349 log->log_start = r5l_ring_add(log, log->log_start,
350 BLOCK_SECTORS);
351 /* current bio hit disk end */
352 if (log->log_start == 0)
353 io->current_bio = NULL;
354
355 io->log_end = log->log_start;
356}
357
358static void r5l_log_stripe(struct r5l_log *log, struct stripe_head *sh,
359 int data_pages, int parity_pages)
360{
361 int i;
362 int meta_size;
363 struct r5l_io_unit *io;
364
365 meta_size =
366 ((sizeof(struct r5l_payload_data_parity) + sizeof(__le32))
367 * data_pages) +
368 sizeof(struct r5l_payload_data_parity) +
369 sizeof(__le32) * parity_pages;
370
371 r5l_get_meta(log, meta_size);
372 io = log->current_io;
373
374 for (i = 0; i < sh->disks; i++) {
375 if (!test_bit(R5_Wantwrite, &sh->dev[i].flags))
376 continue;
377 if (i == sh->pd_idx || i == sh->qd_idx)
378 continue;
379 r5l_append_payload_meta(log, R5LOG_PAYLOAD_DATA,
380 raid5_compute_blocknr(sh, i, 0),
381 sh->dev[i].log_checksum, 0, false);
382 r5l_append_payload_page(log, sh->dev[i].page);
383 }
384
385 if (sh->qd_idx >= 0) {
386 r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY,
387 sh->sector, sh->dev[sh->pd_idx].log_checksum,
388 sh->dev[sh->qd_idx].log_checksum, true);
389 r5l_append_payload_page(log, sh->dev[sh->pd_idx].page);
390 r5l_append_payload_page(log, sh->dev[sh->qd_idx].page);
391 } else {
392 r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY,
393 sh->sector, sh->dev[sh->pd_idx].log_checksum,
394 0, false);
395 r5l_append_payload_page(log, sh->dev[sh->pd_idx].page);
396 }
397
398 list_add_tail(&sh->log_list, &io->stripe_list);
399 atomic_inc(&io->pending_stripe);
400 sh->log_io = io;
401}
402
509ffec7 403static void r5l_wake_reclaim(struct r5l_log *log, sector_t space);
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404/*
405 * running in raid5d, where reclaim could wait for raid5d too (when it flushes
406 * data from log to raid disks), so we shouldn't wait for reclaim here
407 */
408int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh)
409{
410 int write_disks = 0;
411 int data_pages, parity_pages;
412 int meta_size;
413 int reserve;
414 int i;
415
416 if (!log)
417 return -EAGAIN;
418 /* Don't support stripe batch */
419 if (sh->log_io || !test_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags) ||
420 test_bit(STRIPE_SYNCING, &sh->state)) {
421 /* the stripe is written to log, we start writing it to raid */
422 clear_bit(STRIPE_LOG_TRAPPED, &sh->state);
423 return -EAGAIN;
424 }
425
426 for (i = 0; i < sh->disks; i++) {
427 void *addr;
428
429 if (!test_bit(R5_Wantwrite, &sh->dev[i].flags))
430 continue;
431 write_disks++;
432 /* checksum is already calculated in last run */
433 if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
434 continue;
435 addr = kmap_atomic(sh->dev[i].page);
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436 sh->dev[i].log_checksum = crc32c_le(log->uuid_checksum,
437 addr, PAGE_SIZE);
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438 kunmap_atomic(addr);
439 }
440 parity_pages = 1 + !!(sh->qd_idx >= 0);
441 data_pages = write_disks - parity_pages;
442
443 meta_size =
444 ((sizeof(struct r5l_payload_data_parity) + sizeof(__le32))
445 * data_pages) +
446 sizeof(struct r5l_payload_data_parity) +
447 sizeof(__le32) * parity_pages;
448 /* Doesn't work with very big raid array */
449 if (meta_size + sizeof(struct r5l_meta_block) > PAGE_SIZE)
450 return -EINVAL;
451
452 set_bit(STRIPE_LOG_TRAPPED, &sh->state);
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453 /*
454 * The stripe must enter state machine again to finish the write, so
455 * don't delay.
456 */
457 clear_bit(STRIPE_DELAYED, &sh->state);
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458 atomic_inc(&sh->count);
459
460 mutex_lock(&log->io_mutex);
461 /* meta + data */
462 reserve = (1 + write_disks) << (PAGE_SHIFT - 9);
463 if (r5l_has_free_space(log, reserve))
464 r5l_log_stripe(log, sh, data_pages, parity_pages);
465 else {
466 spin_lock(&log->no_space_stripes_lock);
467 list_add_tail(&sh->log_list, &log->no_space_stripes);
468 spin_unlock(&log->no_space_stripes_lock);
469
470 r5l_wake_reclaim(log, reserve);
471 }
472 mutex_unlock(&log->io_mutex);
473
474 return 0;
475}
476
477void r5l_write_stripe_run(struct r5l_log *log)
478{
479 if (!log)
480 return;
481 mutex_lock(&log->io_mutex);
482 r5l_submit_current_io(log);
483 mutex_unlock(&log->io_mutex);
484}
485
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486int r5l_handle_flush_request(struct r5l_log *log, struct bio *bio)
487{
488 if (!log)
489 return -ENODEV;
490 /*
491 * we flush log disk cache first, then write stripe data to raid disks.
492 * So if bio is finished, the log disk cache is flushed already. The
493 * recovery guarantees we can recovery the bio from log disk, so we
494 * don't need to flush again
495 */
496 if (bio->bi_iter.bi_size == 0) {
497 bio_endio(bio);
498 return 0;
499 }
500 bio->bi_rw &= ~REQ_FLUSH;
501 return -EAGAIN;
502}
503
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504/* This will run after log space is reclaimed */
505static void r5l_run_no_space_stripes(struct r5l_log *log)
506{
507 struct stripe_head *sh;
508
509 spin_lock(&log->no_space_stripes_lock);
510 while (!list_empty(&log->no_space_stripes)) {
511 sh = list_first_entry(&log->no_space_stripes,
512 struct stripe_head, log_list);
513 list_del_init(&sh->log_list);
514 set_bit(STRIPE_HANDLE, &sh->state);
515 raid5_release_stripe(sh);
516 }
517 spin_unlock(&log->no_space_stripes_lock);
518}
519
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CH
520static sector_t r5l_reclaimable_space(struct r5l_log *log)
521{
522 return r5l_ring_distance(log, log->last_checkpoint,
523 log->next_checkpoint);
524}
525
526static bool r5l_complete_flushed_ios(struct r5l_log *log)
527{
528 struct r5l_io_unit *io, *next;
529 bool found = false;
530
531 assert_spin_locked(&log->io_list_lock);
532
533 list_for_each_entry_safe(io, next, &log->flushed_ios, log_sibling) {
534 /* don't change list order */
535 if (io->state < IO_UNIT_STRIPE_END)
536 break;
537
538 log->next_checkpoint = io->log_start;
539 log->next_cp_seq = io->seq;
540
541 list_del(&io->log_sibling);
542 r5l_free_io_unit(log, io);
543
544 found = true;
545 }
546
547 return found;
548}
549
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550static void __r5l_stripe_write_finished(struct r5l_io_unit *io)
551{
552 struct r5l_log *log = io->log;
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CH
553 unsigned long flags;
554
555 spin_lock_irqsave(&log->io_list_lock, flags);
556 __r5l_set_io_unit_state(io, IO_UNIT_STRIPE_END);
17036461
CH
557
558 if (!r5l_complete_flushed_ios(log)) {
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559 spin_unlock_irqrestore(&log->io_list_lock, flags);
560 return;
561 }
509ffec7 562
17036461 563 if (r5l_reclaimable_space(log) > log->max_free_space)
509ffec7
CH
564 r5l_wake_reclaim(log, 0);
565
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CH
566 spin_unlock_irqrestore(&log->io_list_lock, flags);
567 wake_up(&log->iounit_wait);
568}
569
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570void r5l_stripe_write_finished(struct stripe_head *sh)
571{
572 struct r5l_io_unit *io;
573
0576b1c6 574 io = sh->log_io;
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575 sh->log_io = NULL;
576
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CH
577 if (io && atomic_dec_and_test(&io->pending_stripe))
578 __r5l_stripe_write_finished(io);
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579}
580
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581static void r5l_log_flush_endio(struct bio *bio)
582{
583 struct r5l_log *log = container_of(bio, struct r5l_log,
584 flush_bio);
585 unsigned long flags;
586 struct r5l_io_unit *io;
587 struct stripe_head *sh;
588
589 spin_lock_irqsave(&log->io_list_lock, flags);
590 list_for_each_entry(io, &log->flushing_ios, log_sibling) {
591 while (!list_empty(&io->stripe_list)) {
592 sh = list_first_entry(&io->stripe_list,
593 struct stripe_head, log_list);
594 list_del_init(&sh->log_list);
595 set_bit(STRIPE_HANDLE, &sh->state);
596 raid5_release_stripe(sh);
597 }
598 }
599 list_splice_tail_init(&log->flushing_ios, &log->flushed_ios);
600 spin_unlock_irqrestore(&log->io_list_lock, flags);
601}
602
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603/*
604 * Starting dispatch IO to raid.
605 * io_unit(meta) consists of a log. There is one situation we want to avoid. A
606 * broken meta in the middle of a log causes recovery can't find meta at the
607 * head of log. If operations require meta at the head persistent in log, we
608 * must make sure meta before it persistent in log too. A case is:
609 *
610 * stripe data/parity is in log, we start write stripe to raid disks. stripe
611 * data/parity must be persistent in log before we do the write to raid disks.
612 *
613 * The solution is we restrictly maintain io_unit list order. In this case, we
614 * only write stripes of an io_unit to raid disks till the io_unit is the first
615 * one whose data/parity is in log.
616 */
617void r5l_flush_stripe_to_raid(struct r5l_log *log)
618{
a8c34f91 619 bool do_flush;
0576b1c6
SL
620 if (!log)
621 return;
0576b1c6
SL
622
623 spin_lock_irq(&log->io_list_lock);
a8c34f91
SL
624 /* flush bio is running */
625 if (!list_empty(&log->flushing_ios)) {
626 spin_unlock_irq(&log->io_list_lock);
627 return;
0576b1c6 628 }
a8c34f91
SL
629 list_splice_tail_init(&log->io_end_ios, &log->flushing_ios);
630 do_flush = !list_empty(&log->flushing_ios);
0576b1c6 631 spin_unlock_irq(&log->io_list_lock);
a8c34f91
SL
632
633 if (!do_flush)
634 return;
635 bio_reset(&log->flush_bio);
636 log->flush_bio.bi_bdev = log->rdev->bdev;
637 log->flush_bio.bi_end_io = r5l_log_flush_endio;
638 submit_bio(WRITE_FLUSH, &log->flush_bio);
0576b1c6
SL
639}
640
0576b1c6
SL
641static void r5l_write_super(struct r5l_log *log, sector_t cp);
642static void r5l_do_reclaim(struct r5l_log *log)
643{
0576b1c6 644 sector_t reclaim_target = xchg(&log->reclaim_target, 0);
17036461
CH
645 sector_t reclaimable;
646 sector_t next_checkpoint;
647 u64 next_cp_seq;
0576b1c6
SL
648
649 spin_lock_irq(&log->io_list_lock);
650 /*
651 * move proper io_unit to reclaim list. We should not change the order.
652 * reclaimable/unreclaimable io_unit can be mixed in the list, we
653 * shouldn't reuse space of an unreclaimable io_unit
654 */
655 while (1) {
17036461
CH
656 reclaimable = r5l_reclaimable_space(log);
657 if (reclaimable >= reclaim_target ||
0576b1c6
SL
658 (list_empty(&log->running_ios) &&
659 list_empty(&log->io_end_ios) &&
a8c34f91
SL
660 list_empty(&log->flushing_ios) &&
661 list_empty(&log->flushed_ios)))
0576b1c6
SL
662 break;
663
17036461
CH
664 md_wakeup_thread(log->rdev->mddev->thread);
665 wait_event_lock_irq(log->iounit_wait,
666 r5l_reclaimable_space(log) > reclaimable,
667 log->io_list_lock);
0576b1c6 668 }
17036461
CH
669
670 next_checkpoint = log->next_checkpoint;
671 next_cp_seq = log->next_cp_seq;
0576b1c6
SL
672 spin_unlock_irq(&log->io_list_lock);
673
17036461
CH
674 BUG_ON(reclaimable < 0);
675 if (reclaimable == 0)
0576b1c6
SL
676 return;
677
0576b1c6
SL
678 /*
679 * write_super will flush cache of each raid disk. We must write super
680 * here, because the log area might be reused soon and we don't want to
681 * confuse recovery
682 */
17036461 683 r5l_write_super(log, next_checkpoint);
0576b1c6
SL
684
685 mutex_lock(&log->io_mutex);
17036461
CH
686 log->last_checkpoint = next_checkpoint;
687 log->last_cp_seq = next_cp_seq;
0576b1c6 688 mutex_unlock(&log->io_mutex);
0576b1c6 689
17036461 690 r5l_run_no_space_stripes(log);
0576b1c6
SL
691}
692
693static void r5l_reclaim_thread(struct md_thread *thread)
694{
695 struct mddev *mddev = thread->mddev;
696 struct r5conf *conf = mddev->private;
697 struct r5l_log *log = conf->log;
698
699 if (!log)
700 return;
701 r5l_do_reclaim(log);
702}
703
f6bed0ef
SL
704static void r5l_wake_reclaim(struct r5l_log *log, sector_t space)
705{
0576b1c6
SL
706 unsigned long target;
707 unsigned long new = (unsigned long)space; /* overflow in theory */
708
709 do {
710 target = log->reclaim_target;
711 if (new < target)
712 return;
713 } while (cmpxchg(&log->reclaim_target, target, new) != target);
714 md_wakeup_thread(log->reclaim_thread);
f6bed0ef
SL
715}
716
e6c033f7
SL
717void r5l_quiesce(struct r5l_log *log, int state)
718{
719 if (!log || state == 2)
720 return;
721 if (state == 0) {
722 log->reclaim_thread = md_register_thread(r5l_reclaim_thread,
723 log->rdev->mddev, "reclaim");
724 } else if (state == 1) {
725 /*
726 * at this point all stripes are finished, so io_unit is at
727 * least in STRIPE_END state
728 */
729 r5l_wake_reclaim(log, -1L);
730 md_unregister_thread(&log->reclaim_thread);
731 r5l_do_reclaim(log);
732 }
733}
734
355810d1
SL
735struct r5l_recovery_ctx {
736 struct page *meta_page; /* current meta */
737 sector_t meta_total_blocks; /* total size of current meta and data */
738 sector_t pos; /* recovery position */
739 u64 seq; /* recovery position seq */
740};
741
742static int r5l_read_meta_block(struct r5l_log *log,
743 struct r5l_recovery_ctx *ctx)
744{
745 struct page *page = ctx->meta_page;
746 struct r5l_meta_block *mb;
747 u32 crc, stored_crc;
748
749 if (!sync_page_io(log->rdev, ctx->pos, PAGE_SIZE, page, READ, false))
750 return -EIO;
751
752 mb = page_address(page);
753 stored_crc = le32_to_cpu(mb->checksum);
754 mb->checksum = 0;
755
756 if (le32_to_cpu(mb->magic) != R5LOG_MAGIC ||
757 le64_to_cpu(mb->seq) != ctx->seq ||
758 mb->version != R5LOG_VERSION ||
759 le64_to_cpu(mb->position) != ctx->pos)
760 return -EINVAL;
761
5cb2fbd6 762 crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);
355810d1
SL
763 if (stored_crc != crc)
764 return -EINVAL;
765
766 if (le32_to_cpu(mb->meta_size) > PAGE_SIZE)
767 return -EINVAL;
768
769 ctx->meta_total_blocks = BLOCK_SECTORS;
770
771 return 0;
772}
773
774static int r5l_recovery_flush_one_stripe(struct r5l_log *log,
775 struct r5l_recovery_ctx *ctx,
776 sector_t stripe_sect,
777 int *offset, sector_t *log_offset)
778{
779 struct r5conf *conf = log->rdev->mddev->private;
780 struct stripe_head *sh;
781 struct r5l_payload_data_parity *payload;
782 int disk_index;
783
784 sh = raid5_get_active_stripe(conf, stripe_sect, 0, 0, 0);
785 while (1) {
786 payload = page_address(ctx->meta_page) + *offset;
787
788 if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_DATA) {
789 raid5_compute_sector(conf,
790 le64_to_cpu(payload->location), 0,
791 &disk_index, sh);
792
793 sync_page_io(log->rdev, *log_offset, PAGE_SIZE,
794 sh->dev[disk_index].page, READ, false);
795 sh->dev[disk_index].log_checksum =
796 le32_to_cpu(payload->checksum[0]);
797 set_bit(R5_Wantwrite, &sh->dev[disk_index].flags);
798 ctx->meta_total_blocks += BLOCK_SECTORS;
799 } else {
800 disk_index = sh->pd_idx;
801 sync_page_io(log->rdev, *log_offset, PAGE_SIZE,
802 sh->dev[disk_index].page, READ, false);
803 sh->dev[disk_index].log_checksum =
804 le32_to_cpu(payload->checksum[0]);
805 set_bit(R5_Wantwrite, &sh->dev[disk_index].flags);
806
807 if (sh->qd_idx >= 0) {
808 disk_index = sh->qd_idx;
809 sync_page_io(log->rdev,
810 r5l_ring_add(log, *log_offset, BLOCK_SECTORS),
811 PAGE_SIZE, sh->dev[disk_index].page,
812 READ, false);
813 sh->dev[disk_index].log_checksum =
814 le32_to_cpu(payload->checksum[1]);
815 set_bit(R5_Wantwrite,
816 &sh->dev[disk_index].flags);
817 }
818 ctx->meta_total_blocks += BLOCK_SECTORS * conf->max_degraded;
819 }
820
821 *log_offset = r5l_ring_add(log, *log_offset,
822 le32_to_cpu(payload->size));
823 *offset += sizeof(struct r5l_payload_data_parity) +
824 sizeof(__le32) *
825 (le32_to_cpu(payload->size) >> (PAGE_SHIFT - 9));
826 if (le16_to_cpu(payload->header.type) == R5LOG_PAYLOAD_PARITY)
827 break;
828 }
829
830 for (disk_index = 0; disk_index < sh->disks; disk_index++) {
831 void *addr;
832 u32 checksum;
833
834 if (!test_bit(R5_Wantwrite, &sh->dev[disk_index].flags))
835 continue;
836 addr = kmap_atomic(sh->dev[disk_index].page);
5cb2fbd6 837 checksum = crc32c_le(log->uuid_checksum, addr, PAGE_SIZE);
355810d1
SL
838 kunmap_atomic(addr);
839 if (checksum != sh->dev[disk_index].log_checksum)
840 goto error;
841 }
842
843 for (disk_index = 0; disk_index < sh->disks; disk_index++) {
844 struct md_rdev *rdev, *rrdev;
845
846 if (!test_and_clear_bit(R5_Wantwrite,
847 &sh->dev[disk_index].flags))
848 continue;
849
850 /* in case device is broken */
851 rdev = rcu_dereference(conf->disks[disk_index].rdev);
852 if (rdev)
853 sync_page_io(rdev, stripe_sect, PAGE_SIZE,
854 sh->dev[disk_index].page, WRITE, false);
855 rrdev = rcu_dereference(conf->disks[disk_index].replacement);
856 if (rrdev)
857 sync_page_io(rrdev, stripe_sect, PAGE_SIZE,
858 sh->dev[disk_index].page, WRITE, false);
859 }
860 raid5_release_stripe(sh);
861 return 0;
862
863error:
864 for (disk_index = 0; disk_index < sh->disks; disk_index++)
865 sh->dev[disk_index].flags = 0;
866 raid5_release_stripe(sh);
867 return -EINVAL;
868}
869
870static int r5l_recovery_flush_one_meta(struct r5l_log *log,
871 struct r5l_recovery_ctx *ctx)
872{
873 struct r5conf *conf = log->rdev->mddev->private;
874 struct r5l_payload_data_parity *payload;
875 struct r5l_meta_block *mb;
876 int offset;
877 sector_t log_offset;
878 sector_t stripe_sector;
879
880 mb = page_address(ctx->meta_page);
881 offset = sizeof(struct r5l_meta_block);
882 log_offset = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
883
884 while (offset < le32_to_cpu(mb->meta_size)) {
885 int dd;
886
887 payload = (void *)mb + offset;
888 stripe_sector = raid5_compute_sector(conf,
889 le64_to_cpu(payload->location), 0, &dd, NULL);
890 if (r5l_recovery_flush_one_stripe(log, ctx, stripe_sector,
891 &offset, &log_offset))
892 return -EINVAL;
893 }
894 return 0;
895}
896
897/* copy data/parity from log to raid disks */
898static void r5l_recovery_flush_log(struct r5l_log *log,
899 struct r5l_recovery_ctx *ctx)
900{
901 while (1) {
902 if (r5l_read_meta_block(log, ctx))
903 return;
904 if (r5l_recovery_flush_one_meta(log, ctx))
905 return;
906 ctx->seq++;
907 ctx->pos = r5l_ring_add(log, ctx->pos, ctx->meta_total_blocks);
908 }
909}
910
911static int r5l_log_write_empty_meta_block(struct r5l_log *log, sector_t pos,
912 u64 seq)
913{
914 struct page *page;
915 struct r5l_meta_block *mb;
916 u32 crc;
917
918 page = alloc_page(GFP_KERNEL | __GFP_ZERO);
919 if (!page)
920 return -ENOMEM;
921 mb = page_address(page);
922 mb->magic = cpu_to_le32(R5LOG_MAGIC);
923 mb->version = R5LOG_VERSION;
924 mb->meta_size = cpu_to_le32(sizeof(struct r5l_meta_block));
925 mb->seq = cpu_to_le64(seq);
926 mb->position = cpu_to_le64(pos);
5cb2fbd6 927 crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);
355810d1
SL
928 mb->checksum = cpu_to_le32(crc);
929
930 if (!sync_page_io(log->rdev, pos, PAGE_SIZE, page, WRITE_FUA, false)) {
931 __free_page(page);
932 return -EIO;
933 }
934 __free_page(page);
935 return 0;
936}
937
f6bed0ef
SL
938static int r5l_recovery_log(struct r5l_log *log)
939{
355810d1
SL
940 struct r5l_recovery_ctx ctx;
941
942 ctx.pos = log->last_checkpoint;
943 ctx.seq = log->last_cp_seq;
944 ctx.meta_page = alloc_page(GFP_KERNEL);
945 if (!ctx.meta_page)
946 return -ENOMEM;
947
948 r5l_recovery_flush_log(log, &ctx);
949 __free_page(ctx.meta_page);
950
951 /*
952 * we did a recovery. Now ctx.pos points to an invalid meta block. New
953 * log will start here. but we can't let superblock point to last valid
954 * meta block. The log might looks like:
955 * | meta 1| meta 2| meta 3|
956 * meta 1 is valid, meta 2 is invalid. meta 3 could be valid. If
957 * superblock points to meta 1, we write a new valid meta 2n. if crash
958 * happens again, new recovery will start from meta 1. Since meta 2n is
959 * valid now, recovery will think meta 3 is valid, which is wrong.
960 * The solution is we create a new meta in meta2 with its seq == meta
961 * 1's seq + 10 and let superblock points to meta2. The same recovery will
962 * not think meta 3 is a valid meta, because its seq doesn't match
963 */
964 if (ctx.seq > log->last_cp_seq + 1) {
965 int ret;
966
967 ret = r5l_log_write_empty_meta_block(log, ctx.pos, ctx.seq + 10);
968 if (ret)
969 return ret;
970 log->seq = ctx.seq + 11;
971 log->log_start = r5l_ring_add(log, ctx.pos, BLOCK_SECTORS);
972 r5l_write_super(log, ctx.pos);
973 } else {
974 log->log_start = ctx.pos;
975 log->seq = ctx.seq;
976 }
f6bed0ef
SL
977 return 0;
978}
979
980static void r5l_write_super(struct r5l_log *log, sector_t cp)
981{
982 struct mddev *mddev = log->rdev->mddev;
983
984 log->rdev->journal_tail = cp;
985 set_bit(MD_CHANGE_DEVS, &mddev->flags);
986}
987
988static int r5l_load_log(struct r5l_log *log)
989{
990 struct md_rdev *rdev = log->rdev;
991 struct page *page;
992 struct r5l_meta_block *mb;
993 sector_t cp = log->rdev->journal_tail;
994 u32 stored_crc, expected_crc;
995 bool create_super = false;
996 int ret;
997
998 /* Make sure it's valid */
999 if (cp >= rdev->sectors || round_down(cp, BLOCK_SECTORS) != cp)
1000 cp = 0;
1001 page = alloc_page(GFP_KERNEL);
1002 if (!page)
1003 return -ENOMEM;
1004
1005 if (!sync_page_io(rdev, cp, PAGE_SIZE, page, READ, false)) {
1006 ret = -EIO;
1007 goto ioerr;
1008 }
1009 mb = page_address(page);
1010
1011 if (le32_to_cpu(mb->magic) != R5LOG_MAGIC ||
1012 mb->version != R5LOG_VERSION) {
1013 create_super = true;
1014 goto create;
1015 }
1016 stored_crc = le32_to_cpu(mb->checksum);
1017 mb->checksum = 0;
5cb2fbd6 1018 expected_crc = crc32c_le(log->uuid_checksum, mb, PAGE_SIZE);
f6bed0ef
SL
1019 if (stored_crc != expected_crc) {
1020 create_super = true;
1021 goto create;
1022 }
1023 if (le64_to_cpu(mb->position) != cp) {
1024 create_super = true;
1025 goto create;
1026 }
1027create:
1028 if (create_super) {
1029 log->last_cp_seq = prandom_u32();
1030 cp = 0;
1031 /*
1032 * Make sure super points to correct address. Log might have
1033 * data very soon. If super hasn't correct log tail address,
1034 * recovery can't find the log
1035 */
1036 r5l_write_super(log, cp);
1037 } else
1038 log->last_cp_seq = le64_to_cpu(mb->seq);
1039
1040 log->device_size = round_down(rdev->sectors, BLOCK_SECTORS);
0576b1c6
SL
1041 log->max_free_space = log->device_size >> RECLAIM_MAX_FREE_SPACE_SHIFT;
1042 if (log->max_free_space > RECLAIM_MAX_FREE_SPACE)
1043 log->max_free_space = RECLAIM_MAX_FREE_SPACE;
f6bed0ef
SL
1044 log->last_checkpoint = cp;
1045
1046 __free_page(page);
1047
1048 return r5l_recovery_log(log);
1049ioerr:
1050 __free_page(page);
1051 return ret;
1052}
1053
1054int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
1055{
1056 struct r5l_log *log;
1057
1058 if (PAGE_SIZE != 4096)
1059 return -EINVAL;
1060 log = kzalloc(sizeof(*log), GFP_KERNEL);
1061 if (!log)
1062 return -ENOMEM;
1063 log->rdev = rdev;
1064
5cb2fbd6
SL
1065 log->uuid_checksum = crc32c_le(~0, rdev->mddev->uuid,
1066 sizeof(rdev->mddev->uuid));
f6bed0ef
SL
1067
1068 mutex_init(&log->io_mutex);
1069
1070 spin_lock_init(&log->io_list_lock);
1071 INIT_LIST_HEAD(&log->running_ios);
0576b1c6 1072 INIT_LIST_HEAD(&log->io_end_ios);
a8c34f91
SL
1073 INIT_LIST_HEAD(&log->flushing_ios);
1074 INIT_LIST_HEAD(&log->flushed_ios);
1075 bio_init(&log->flush_bio);
f6bed0ef
SL
1076
1077 log->io_kc = KMEM_CACHE(r5l_io_unit, 0);
1078 if (!log->io_kc)
1079 goto io_kc;
1080
0576b1c6
SL
1081 log->reclaim_thread = md_register_thread(r5l_reclaim_thread,
1082 log->rdev->mddev, "reclaim");
1083 if (!log->reclaim_thread)
1084 goto reclaim_thread;
0fd22b45 1085 init_waitqueue_head(&log->iounit_wait);
0576b1c6 1086
f6bed0ef
SL
1087 INIT_LIST_HEAD(&log->no_space_stripes);
1088 spin_lock_init(&log->no_space_stripes_lock);
1089
1090 if (r5l_load_log(log))
1091 goto error;
1092
1093 conf->log = log;
1094 return 0;
1095error:
0576b1c6
SL
1096 md_unregister_thread(&log->reclaim_thread);
1097reclaim_thread:
f6bed0ef
SL
1098 kmem_cache_destroy(log->io_kc);
1099io_kc:
1100 kfree(log);
1101 return -EINVAL;
1102}
1103
1104void r5l_exit_log(struct r5l_log *log)
1105{
0576b1c6 1106 md_unregister_thread(&log->reclaim_thread);
f6bed0ef
SL
1107 kmem_cache_destroy(log->io_kc);
1108 kfree(log);
1109}