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1/*
2 * Copyright (C) 2003 Sistina Software Limited.
3 * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm-bio-record.h"
9
10#include <linux/init.h>
11#include <linux/mempool.h>
12#include <linux/module.h>
13#include <linux/pagemap.h>
14#include <linux/slab.h>
15#include <linux/workqueue.h>
16#include <linux/device-mapper.h>
17#include <linux/dm-io.h>
18#include <linux/dm-dirty-log.h>
19#include <linux/dm-kcopyd.h>
20#include <linux/dm-region-hash.h>
21
22#define DM_MSG_PREFIX "raid1"
23
24#define MAX_RECOVERY 1 /* Maximum number of regions recovered in parallel. */
25
26#define MAX_NR_MIRRORS (DM_KCOPYD_MAX_REGIONS + 1)
27
28#define DM_RAID1_HANDLE_ERRORS 0x01
29#define DM_RAID1_KEEP_LOG 0x02
30#define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS)
31#define keep_log(p) ((p)->features & DM_RAID1_KEEP_LOG)
32
33static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped);
34
35/*-----------------------------------------------------------------
36 * Mirror set structures.
37 *---------------------------------------------------------------*/
38enum dm_raid1_error {
39 DM_RAID1_WRITE_ERROR,
40 DM_RAID1_FLUSH_ERROR,
41 DM_RAID1_SYNC_ERROR,
42 DM_RAID1_READ_ERROR
43};
44
45struct mirror {
46 struct mirror_set *ms;
47 atomic_t error_count;
48 unsigned long error_type;
49 struct dm_dev *dev;
50 sector_t offset;
51};
52
53struct mirror_set {
54 struct dm_target *ti;
55 struct list_head list;
56
57 uint64_t features;
58
59 spinlock_t lock; /* protects the lists */
60 struct bio_list reads;
61 struct bio_list writes;
62 struct bio_list failures;
63 struct bio_list holds; /* bios are waiting until suspend */
64
65 struct dm_region_hash *rh;
66 struct dm_kcopyd_client *kcopyd_client;
67 struct dm_io_client *io_client;
68
69 /* recovery */
70 region_t nr_regions;
71 int in_sync;
72 int log_failure;
73 int leg_failure;
74 atomic_t suspend;
75
76 atomic_t default_mirror; /* Default mirror */
77
78 struct workqueue_struct *kmirrord_wq;
79 struct work_struct kmirrord_work;
80 struct timer_list timer;
81 unsigned long timer_pending;
82
83 struct work_struct trigger_event;
84
85 unsigned nr_mirrors;
86 struct mirror mirror[];
87};
88
89DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(raid1_resync_throttle,
90 "A percentage of time allocated for raid resynchronization");
91
92static void wakeup_mirrord(void *context)
93{
94 struct mirror_set *ms = context;
95
96 queue_work(ms->kmirrord_wq, &ms->kmirrord_work);
97}
98
99static void delayed_wake_fn(struct timer_list *t)
100{
101 struct mirror_set *ms = from_timer(ms, t, timer);
102
103 clear_bit(0, &ms->timer_pending);
104 wakeup_mirrord(ms);
105}
106
107static void delayed_wake(struct mirror_set *ms)
108{
109 if (test_and_set_bit(0, &ms->timer_pending))
110 return;
111
112 ms->timer.expires = jiffies + HZ / 5;
113 add_timer(&ms->timer);
114}
115
116static void wakeup_all_recovery_waiters(void *context)
117{
118 wake_up_all(&_kmirrord_recovery_stopped);
119}
120
121static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw)
122{
123 unsigned long flags;
124 int should_wake = 0;
125 struct bio_list *bl;
126
127 bl = (rw == WRITE) ? &ms->writes : &ms->reads;
128 spin_lock_irqsave(&ms->lock, flags);
129 should_wake = !(bl->head);
130 bio_list_add(bl, bio);
131 spin_unlock_irqrestore(&ms->lock, flags);
132
133 if (should_wake)
134 wakeup_mirrord(ms);
135}
136
137static void dispatch_bios(void *context, struct bio_list *bio_list)
138{
139 struct mirror_set *ms = context;
140 struct bio *bio;
141
142 while ((bio = bio_list_pop(bio_list)))
143 queue_bio(ms, bio, WRITE);
144}
145
146struct dm_raid1_bio_record {
147 struct mirror *m;
148 /* if details->bi_bdev == NULL, details were not saved */
149 struct dm_bio_details details;
150 region_t write_region;
151};
152
153/*
154 * Every mirror should look like this one.
155 */
156#define DEFAULT_MIRROR 0
157
158/*
159 * This is yucky. We squirrel the mirror struct away inside
160 * bi_next for read/write buffers. This is safe since the bh
161 * doesn't get submitted to the lower levels of block layer.
162 */
163static struct mirror *bio_get_m(struct bio *bio)
164{
165 return (struct mirror *) bio->bi_next;
166}
167
168static void bio_set_m(struct bio *bio, struct mirror *m)
169{
170 bio->bi_next = (struct bio *) m;
171}
172
173static struct mirror *get_default_mirror(struct mirror_set *ms)
174{
175 return &ms->mirror[atomic_read(&ms->default_mirror)];
176}
177
178static void set_default_mirror(struct mirror *m)
179{
180 struct mirror_set *ms = m->ms;
181 struct mirror *m0 = &(ms->mirror[0]);
182
183 atomic_set(&ms->default_mirror, m - m0);
184}
185
186static struct mirror *get_valid_mirror(struct mirror_set *ms)
187{
188 struct mirror *m;
189
190 for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++)
191 if (!atomic_read(&m->error_count))
192 return m;
193
194 return NULL;
195}
196
197/* fail_mirror
198 * @m: mirror device to fail
199 * @error_type: one of the enum's, DM_RAID1_*_ERROR
200 *
201 * If errors are being handled, record the type of
202 * error encountered for this device. If this type
203 * of error has already been recorded, we can return;
204 * otherwise, we must signal userspace by triggering
205 * an event. Additionally, if the device is the
206 * primary device, we must choose a new primary, but
207 * only if the mirror is in-sync.
208 *
209 * This function must not block.
210 */
211static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
212{
213 struct mirror_set *ms = m->ms;
214 struct mirror *new;
215
216 ms->leg_failure = 1;
217
218 /*
219 * error_count is used for nothing more than a
220 * simple way to tell if a device has encountered
221 * errors.
222 */
223 atomic_inc(&m->error_count);
224
225 if (test_and_set_bit(error_type, &m->error_type))
226 return;
227
228 if (!errors_handled(ms))
229 return;
230
231 if (m != get_default_mirror(ms))
232 goto out;
233
234 if (!ms->in_sync && !keep_log(ms)) {
235 /*
236 * Better to issue requests to same failing device
237 * than to risk returning corrupt data.
238 */
239 DMERR("Primary mirror (%s) failed while out-of-sync: "
240 "Reads may fail.", m->dev->name);
241 goto out;
242 }
243
244 new = get_valid_mirror(ms);
245 if (new)
246 set_default_mirror(new);
247 else
248 DMWARN("All sides of mirror have failed.");
249
250out:
251 schedule_work(&ms->trigger_event);
252}
253
254static int mirror_flush(struct dm_target *ti)
255{
256 struct mirror_set *ms = ti->private;
257 unsigned long error_bits;
258
259 unsigned int i;
260 struct dm_io_region io[MAX_NR_MIRRORS];
261 struct mirror *m;
262 struct dm_io_request io_req = {
263 .bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC,
264 .mem.type = DM_IO_KMEM,
265 .mem.ptr.addr = NULL,
266 .client = ms->io_client,
267 };
268
269 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) {
270 io[i].bdev = m->dev->bdev;
271 io[i].sector = 0;
272 io[i].count = 0;
273 }
274
275 error_bits = -1;
276 dm_io(&io_req, ms->nr_mirrors, io, &error_bits);
277 if (unlikely(error_bits != 0)) {
278 for (i = 0; i < ms->nr_mirrors; i++)
279 if (test_bit(i, &error_bits))
280 fail_mirror(ms->mirror + i,
281 DM_RAID1_FLUSH_ERROR);
282 return -EIO;
283 }
284
285 return 0;
286}
287
288/*-----------------------------------------------------------------
289 * Recovery.
290 *
291 * When a mirror is first activated we may find that some regions
292 * are in the no-sync state. We have to recover these by
293 * recopying from the default mirror to all the others.
294 *---------------------------------------------------------------*/
295static void recovery_complete(int read_err, unsigned long write_err,
296 void *context)
297{
298 struct dm_region *reg = context;
299 struct mirror_set *ms = dm_rh_region_context(reg);
300 int m, bit = 0;
301
302 if (read_err) {
303 /* Read error means the failure of default mirror. */
304 DMERR_LIMIT("Unable to read primary mirror during recovery");
305 fail_mirror(get_default_mirror(ms), DM_RAID1_SYNC_ERROR);
306 }
307
308 if (write_err) {
309 DMERR_LIMIT("Write error during recovery (error = 0x%lx)",
310 write_err);
311 /*
312 * Bits correspond to devices (excluding default mirror).
313 * The default mirror cannot change during recovery.
314 */
315 for (m = 0; m < ms->nr_mirrors; m++) {
316 if (&ms->mirror[m] == get_default_mirror(ms))
317 continue;
318 if (test_bit(bit, &write_err))
319 fail_mirror(ms->mirror + m,
320 DM_RAID1_SYNC_ERROR);
321 bit++;
322 }
323 }
324
325 dm_rh_recovery_end(reg, !(read_err || write_err));
326}
327
328static void recover(struct mirror_set *ms, struct dm_region *reg)
329{
330 unsigned i;
331 struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest;
332 struct mirror *m;
333 unsigned long flags = 0;
334 region_t key = dm_rh_get_region_key(reg);
335 sector_t region_size = dm_rh_get_region_size(ms->rh);
336
337 /* fill in the source */
338 m = get_default_mirror(ms);
339 from.bdev = m->dev->bdev;
340 from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
341 if (key == (ms->nr_regions - 1)) {
342 /*
343 * The final region may be smaller than
344 * region_size.
345 */
346 from.count = ms->ti->len & (region_size - 1);
347 if (!from.count)
348 from.count = region_size;
349 } else
350 from.count = region_size;
351
352 /* fill in the destinations */
353 for (i = 0, dest = to; i < ms->nr_mirrors; i++) {
354 if (&ms->mirror[i] == get_default_mirror(ms))
355 continue;
356
357 m = ms->mirror + i;
358 dest->bdev = m->dev->bdev;
359 dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
360 dest->count = from.count;
361 dest++;
362 }
363
364 /* hand to kcopyd */
365 if (!errors_handled(ms))
366 flags |= BIT(DM_KCOPYD_IGNORE_ERROR);
367
368 dm_kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to,
369 flags, recovery_complete, reg);
370}
371
372static void reset_ms_flags(struct mirror_set *ms)
373{
374 unsigned int m;
375
376 ms->leg_failure = 0;
377 for (m = 0; m < ms->nr_mirrors; m++) {
378 atomic_set(&(ms->mirror[m].error_count), 0);
379 ms->mirror[m].error_type = 0;
380 }
381}
382
383static void do_recovery(struct mirror_set *ms)
384{
385 struct dm_region *reg;
386 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
387
388 /*
389 * Start quiescing some regions.
390 */
391 dm_rh_recovery_prepare(ms->rh);
392
393 /*
394 * Copy any already quiesced regions.
395 */
396 while ((reg = dm_rh_recovery_start(ms->rh)))
397 recover(ms, reg);
398
399 /*
400 * Update the in sync flag.
401 */
402 if (!ms->in_sync &&
403 (log->type->get_sync_count(log) == ms->nr_regions)) {
404 /* the sync is complete */
405 dm_table_event(ms->ti->table);
406 ms->in_sync = 1;
407 reset_ms_flags(ms);
408 }
409}
410
411/*-----------------------------------------------------------------
412 * Reads
413 *---------------------------------------------------------------*/
414static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector)
415{
416 struct mirror *m = get_default_mirror(ms);
417
418 do {
419 if (likely(!atomic_read(&m->error_count)))
420 return m;
421
422 if (m-- == ms->mirror)
423 m += ms->nr_mirrors;
424 } while (m != get_default_mirror(ms));
425
426 return NULL;
427}
428
429static int default_ok(struct mirror *m)
430{
431 struct mirror *default_mirror = get_default_mirror(m->ms);
432
433 return !atomic_read(&default_mirror->error_count);
434}
435
436static int mirror_available(struct mirror_set *ms, struct bio *bio)
437{
438 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
439 region_t region = dm_rh_bio_to_region(ms->rh, bio);
440
441 if (log->type->in_sync(log, region, 0))
442 return choose_mirror(ms, bio->bi_iter.bi_sector) ? 1 : 0;
443
444 return 0;
445}
446
447/*
448 * remap a buffer to a particular mirror.
449 */
450static sector_t map_sector(struct mirror *m, struct bio *bio)
451{
452 if (unlikely(!bio->bi_iter.bi_size))
453 return 0;
454 return m->offset + dm_target_offset(m->ms->ti, bio->bi_iter.bi_sector);
455}
456
457static void map_bio(struct mirror *m, struct bio *bio)
458{
459 bio_set_dev(bio, m->dev->bdev);
460 bio->bi_iter.bi_sector = map_sector(m, bio);
461}
462
463static void map_region(struct dm_io_region *io, struct mirror *m,
464 struct bio *bio)
465{
466 io->bdev = m->dev->bdev;
467 io->sector = map_sector(m, bio);
468 io->count = bio_sectors(bio);
469}
470
471static void hold_bio(struct mirror_set *ms, struct bio *bio)
472{
473 /*
474 * Lock is required to avoid race condition during suspend
475 * process.
476 */
477 spin_lock_irq(&ms->lock);
478
479 if (atomic_read(&ms->suspend)) {
480 spin_unlock_irq(&ms->lock);
481
482 /*
483 * If device is suspended, complete the bio.
484 */
485 if (dm_noflush_suspending(ms->ti))
486 bio->bi_status = BLK_STS_DM_REQUEUE;
487 else
488 bio->bi_status = BLK_STS_IOERR;
489
490 bio_endio(bio);
491 return;
492 }
493
494 /*
495 * Hold bio until the suspend is complete.
496 */
497 bio_list_add(&ms->holds, bio);
498 spin_unlock_irq(&ms->lock);
499}
500
501/*-----------------------------------------------------------------
502 * Reads
503 *---------------------------------------------------------------*/
504static void read_callback(unsigned long error, void *context)
505{
506 struct bio *bio = context;
507 struct mirror *m;
508
509 m = bio_get_m(bio);
510 bio_set_m(bio, NULL);
511
512 if (likely(!error)) {
513 bio_endio(bio);
514 return;
515 }
516
517 fail_mirror(m, DM_RAID1_READ_ERROR);
518
519 if (likely(default_ok(m)) || mirror_available(m->ms, bio)) {
520 DMWARN_LIMIT("Read failure on mirror device %s. "
521 "Trying alternative device.",
522 m->dev->name);
523 queue_bio(m->ms, bio, bio_data_dir(bio));
524 return;
525 }
526
527 DMERR_LIMIT("Read failure on mirror device %s. Failing I/O.",
528 m->dev->name);
529 bio_io_error(bio);
530}
531
532/* Asynchronous read. */
533static void read_async_bio(struct mirror *m, struct bio *bio)
534{
535 struct dm_io_region io;
536 struct dm_io_request io_req = {
537 .bi_opf = REQ_OP_READ,
538 .mem.type = DM_IO_BIO,
539 .mem.ptr.bio = bio,
540 .notify.fn = read_callback,
541 .notify.context = bio,
542 .client = m->ms->io_client,
543 };
544
545 map_region(&io, m, bio);
546 bio_set_m(bio, m);
547 BUG_ON(dm_io(&io_req, 1, &io, NULL));
548}
549
550static inline int region_in_sync(struct mirror_set *ms, region_t region,
551 int may_block)
552{
553 int state = dm_rh_get_state(ms->rh, region, may_block);
554 return state == DM_RH_CLEAN || state == DM_RH_DIRTY;
555}
556
557static void do_reads(struct mirror_set *ms, struct bio_list *reads)
558{
559 region_t region;
560 struct bio *bio;
561 struct mirror *m;
562
563 while ((bio = bio_list_pop(reads))) {
564 region = dm_rh_bio_to_region(ms->rh, bio);
565 m = get_default_mirror(ms);
566
567 /*
568 * We can only read balance if the region is in sync.
569 */
570 if (likely(region_in_sync(ms, region, 1)))
571 m = choose_mirror(ms, bio->bi_iter.bi_sector);
572 else if (m && atomic_read(&m->error_count))
573 m = NULL;
574
575 if (likely(m))
576 read_async_bio(m, bio);
577 else
578 bio_io_error(bio);
579 }
580}
581
582/*-----------------------------------------------------------------
583 * Writes.
584 *
585 * We do different things with the write io depending on the
586 * state of the region that it's in:
587 *
588 * SYNC: increment pending, use kcopyd to write to *all* mirrors
589 * RECOVERING: delay the io until recovery completes
590 * NOSYNC: increment pending, just write to the default mirror
591 *---------------------------------------------------------------*/
592
593
594static void write_callback(unsigned long error, void *context)
595{
596 unsigned i;
597 struct bio *bio = (struct bio *) context;
598 struct mirror_set *ms;
599 int should_wake = 0;
600 unsigned long flags;
601
602 ms = bio_get_m(bio)->ms;
603 bio_set_m(bio, NULL);
604
605 /*
606 * NOTE: We don't decrement the pending count here,
607 * instead it is done by the targets endio function.
608 * This way we handle both writes to SYNC and NOSYNC
609 * regions with the same code.
610 */
611 if (likely(!error)) {
612 bio_endio(bio);
613 return;
614 }
615
616 /*
617 * If the bio is discard, return an error, but do not
618 * degrade the array.
619 */
620 if (bio_op(bio) == REQ_OP_DISCARD) {
621 bio->bi_status = BLK_STS_NOTSUPP;
622 bio_endio(bio);
623 return;
624 }
625
626 for (i = 0; i < ms->nr_mirrors; i++)
627 if (test_bit(i, &error))
628 fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR);
629
630 /*
631 * Need to raise event. Since raising
632 * events can block, we need to do it in
633 * the main thread.
634 */
635 spin_lock_irqsave(&ms->lock, flags);
636 if (!ms->failures.head)
637 should_wake = 1;
638 bio_list_add(&ms->failures, bio);
639 spin_unlock_irqrestore(&ms->lock, flags);
640 if (should_wake)
641 wakeup_mirrord(ms);
642}
643
644static void do_write(struct mirror_set *ms, struct bio *bio)
645{
646 unsigned int i;
647 struct dm_io_region io[MAX_NR_MIRRORS], *dest = io;
648 struct mirror *m;
649 blk_opf_t op_flags = bio->bi_opf & (REQ_FUA | REQ_PREFLUSH);
650 struct dm_io_request io_req = {
651 .bi_opf = REQ_OP_WRITE | op_flags,
652 .mem.type = DM_IO_BIO,
653 .mem.ptr.bio = bio,
654 .notify.fn = write_callback,
655 .notify.context = bio,
656 .client = ms->io_client,
657 };
658
659 if (bio_op(bio) == REQ_OP_DISCARD) {
660 io_req.bi_opf = REQ_OP_DISCARD | op_flags;
661 io_req.mem.type = DM_IO_KMEM;
662 io_req.mem.ptr.addr = NULL;
663 }
664
665 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++)
666 map_region(dest++, m, bio);
667
668 /*
669 * Use default mirror because we only need it to retrieve the reference
670 * to the mirror set in write_callback().
671 */
672 bio_set_m(bio, get_default_mirror(ms));
673
674 BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL));
675}
676
677static void do_writes(struct mirror_set *ms, struct bio_list *writes)
678{
679 int state;
680 struct bio *bio;
681 struct bio_list sync, nosync, recover, *this_list = NULL;
682 struct bio_list requeue;
683 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
684 region_t region;
685
686 if (!writes->head)
687 return;
688
689 /*
690 * Classify each write.
691 */
692 bio_list_init(&sync);
693 bio_list_init(&nosync);
694 bio_list_init(&recover);
695 bio_list_init(&requeue);
696
697 while ((bio = bio_list_pop(writes))) {
698 if ((bio->bi_opf & REQ_PREFLUSH) ||
699 (bio_op(bio) == REQ_OP_DISCARD)) {
700 bio_list_add(&sync, bio);
701 continue;
702 }
703
704 region = dm_rh_bio_to_region(ms->rh, bio);
705
706 if (log->type->is_remote_recovering &&
707 log->type->is_remote_recovering(log, region)) {
708 bio_list_add(&requeue, bio);
709 continue;
710 }
711
712 state = dm_rh_get_state(ms->rh, region, 1);
713 switch (state) {
714 case DM_RH_CLEAN:
715 case DM_RH_DIRTY:
716 this_list = &sync;
717 break;
718
719 case DM_RH_NOSYNC:
720 this_list = &nosync;
721 break;
722
723 case DM_RH_RECOVERING:
724 this_list = &recover;
725 break;
726 }
727
728 bio_list_add(this_list, bio);
729 }
730
731 /*
732 * Add bios that are delayed due to remote recovery
733 * back on to the write queue
734 */
735 if (unlikely(requeue.head)) {
736 spin_lock_irq(&ms->lock);
737 bio_list_merge(&ms->writes, &requeue);
738 spin_unlock_irq(&ms->lock);
739 delayed_wake(ms);
740 }
741
742 /*
743 * Increment the pending counts for any regions that will
744 * be written to (writes to recover regions are going to
745 * be delayed).
746 */
747 dm_rh_inc_pending(ms->rh, &sync);
748 dm_rh_inc_pending(ms->rh, &nosync);
749
750 /*
751 * If the flush fails on a previous call and succeeds here,
752 * we must not reset the log_failure variable. We need
753 * userspace interaction to do that.
754 */
755 ms->log_failure = dm_rh_flush(ms->rh) ? 1 : ms->log_failure;
756
757 /*
758 * Dispatch io.
759 */
760 if (unlikely(ms->log_failure) && errors_handled(ms)) {
761 spin_lock_irq(&ms->lock);
762 bio_list_merge(&ms->failures, &sync);
763 spin_unlock_irq(&ms->lock);
764 wakeup_mirrord(ms);
765 } else
766 while ((bio = bio_list_pop(&sync)))
767 do_write(ms, bio);
768
769 while ((bio = bio_list_pop(&recover)))
770 dm_rh_delay(ms->rh, bio);
771
772 while ((bio = bio_list_pop(&nosync))) {
773 if (unlikely(ms->leg_failure) && errors_handled(ms) && !keep_log(ms)) {
774 spin_lock_irq(&ms->lock);
775 bio_list_add(&ms->failures, bio);
776 spin_unlock_irq(&ms->lock);
777 wakeup_mirrord(ms);
778 } else {
779 map_bio(get_default_mirror(ms), bio);
780 submit_bio_noacct(bio);
781 }
782 }
783}
784
785static void do_failures(struct mirror_set *ms, struct bio_list *failures)
786{
787 struct bio *bio;
788
789 if (likely(!failures->head))
790 return;
791
792 /*
793 * If the log has failed, unattempted writes are being
794 * put on the holds list. We can't issue those writes
795 * until a log has been marked, so we must store them.
796 *
797 * If a 'noflush' suspend is in progress, we can requeue
798 * the I/O's to the core. This give userspace a chance
799 * to reconfigure the mirror, at which point the core
800 * will reissue the writes. If the 'noflush' flag is
801 * not set, we have no choice but to return errors.
802 *
803 * Some writes on the failures list may have been
804 * submitted before the log failure and represent a
805 * failure to write to one of the devices. It is ok
806 * for us to treat them the same and requeue them
807 * as well.
808 */
809 while ((bio = bio_list_pop(failures))) {
810 if (!ms->log_failure) {
811 ms->in_sync = 0;
812 dm_rh_mark_nosync(ms->rh, bio);
813 }
814
815 /*
816 * If all the legs are dead, fail the I/O.
817 * If the device has failed and keep_log is enabled,
818 * fail the I/O.
819 *
820 * If we have been told to handle errors, and keep_log
821 * isn't enabled, hold the bio and wait for userspace to
822 * deal with the problem.
823 *
824 * Otherwise pretend that the I/O succeeded. (This would
825 * be wrong if the failed leg returned after reboot and
826 * got replicated back to the good legs.)
827 */
828 if (unlikely(!get_valid_mirror(ms) || (keep_log(ms) && ms->log_failure)))
829 bio_io_error(bio);
830 else if (errors_handled(ms) && !keep_log(ms))
831 hold_bio(ms, bio);
832 else
833 bio_endio(bio);
834 }
835}
836
837static void trigger_event(struct work_struct *work)
838{
839 struct mirror_set *ms =
840 container_of(work, struct mirror_set, trigger_event);
841
842 dm_table_event(ms->ti->table);
843}
844
845/*-----------------------------------------------------------------
846 * kmirrord
847 *---------------------------------------------------------------*/
848static void do_mirror(struct work_struct *work)
849{
850 struct mirror_set *ms = container_of(work, struct mirror_set,
851 kmirrord_work);
852 struct bio_list reads, writes, failures;
853 unsigned long flags;
854
855 spin_lock_irqsave(&ms->lock, flags);
856 reads = ms->reads;
857 writes = ms->writes;
858 failures = ms->failures;
859 bio_list_init(&ms->reads);
860 bio_list_init(&ms->writes);
861 bio_list_init(&ms->failures);
862 spin_unlock_irqrestore(&ms->lock, flags);
863
864 dm_rh_update_states(ms->rh, errors_handled(ms));
865 do_recovery(ms);
866 do_reads(ms, &reads);
867 do_writes(ms, &writes);
868 do_failures(ms, &failures);
869}
870
871/*-----------------------------------------------------------------
872 * Target functions
873 *---------------------------------------------------------------*/
874static struct mirror_set *alloc_context(unsigned int nr_mirrors,
875 uint32_t region_size,
876 struct dm_target *ti,
877 struct dm_dirty_log *dl)
878{
879 struct mirror_set *ms =
880 kzalloc(struct_size(ms, mirror, nr_mirrors), GFP_KERNEL);
881
882 if (!ms) {
883 ti->error = "Cannot allocate mirror context";
884 return NULL;
885 }
886
887 spin_lock_init(&ms->lock);
888 bio_list_init(&ms->reads);
889 bio_list_init(&ms->writes);
890 bio_list_init(&ms->failures);
891 bio_list_init(&ms->holds);
892
893 ms->ti = ti;
894 ms->nr_mirrors = nr_mirrors;
895 ms->nr_regions = dm_sector_div_up(ti->len, region_size);
896 ms->in_sync = 0;
897 ms->log_failure = 0;
898 ms->leg_failure = 0;
899 atomic_set(&ms->suspend, 0);
900 atomic_set(&ms->default_mirror, DEFAULT_MIRROR);
901
902 ms->io_client = dm_io_client_create();
903 if (IS_ERR(ms->io_client)) {
904 ti->error = "Error creating dm_io client";
905 kfree(ms);
906 return NULL;
907 }
908
909 ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord,
910 wakeup_all_recovery_waiters,
911 ms->ti->begin, MAX_RECOVERY,
912 dl, region_size, ms->nr_regions);
913 if (IS_ERR(ms->rh)) {
914 ti->error = "Error creating dirty region hash";
915 dm_io_client_destroy(ms->io_client);
916 kfree(ms);
917 return NULL;
918 }
919
920 return ms;
921}
922
923static void free_context(struct mirror_set *ms, struct dm_target *ti,
924 unsigned int m)
925{
926 while (m--)
927 dm_put_device(ti, ms->mirror[m].dev);
928
929 dm_io_client_destroy(ms->io_client);
930 dm_region_hash_destroy(ms->rh);
931 kfree(ms);
932}
933
934static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
935 unsigned int mirror, char **argv)
936{
937 unsigned long long offset;
938 char dummy;
939 int ret;
940
941 if (sscanf(argv[1], "%llu%c", &offset, &dummy) != 1 ||
942 offset != (sector_t)offset) {
943 ti->error = "Invalid offset";
944 return -EINVAL;
945 }
946
947 ret = dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
948 &ms->mirror[mirror].dev);
949 if (ret) {
950 ti->error = "Device lookup failure";
951 return ret;
952 }
953
954 ms->mirror[mirror].ms = ms;
955 atomic_set(&(ms->mirror[mirror].error_count), 0);
956 ms->mirror[mirror].error_type = 0;
957 ms->mirror[mirror].offset = offset;
958
959 return 0;
960}
961
962/*
963 * Create dirty log: log_type #log_params <log_params>
964 */
965static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
966 unsigned argc, char **argv,
967 unsigned *args_used)
968{
969 unsigned param_count;
970 struct dm_dirty_log *dl;
971 char dummy;
972
973 if (argc < 2) {
974 ti->error = "Insufficient mirror log arguments";
975 return NULL;
976 }
977
978 if (sscanf(argv[1], "%u%c", ¶m_count, &dummy) != 1) {
979 ti->error = "Invalid mirror log argument count";
980 return NULL;
981 }
982
983 *args_used = 2 + param_count;
984
985 if (argc < *args_used) {
986 ti->error = "Insufficient mirror log arguments";
987 return NULL;
988 }
989
990 dl = dm_dirty_log_create(argv[0], ti, mirror_flush, param_count,
991 argv + 2);
992 if (!dl) {
993 ti->error = "Error creating mirror dirty log";
994 return NULL;
995 }
996
997 return dl;
998}
999
1000static int parse_features(struct mirror_set *ms, unsigned argc, char **argv,
1001 unsigned *args_used)
1002{
1003 unsigned num_features;
1004 struct dm_target *ti = ms->ti;
1005 char dummy;
1006 int i;
1007
1008 *args_used = 0;
1009
1010 if (!argc)
1011 return 0;
1012
1013 if (sscanf(argv[0], "%u%c", &num_features, &dummy) != 1) {
1014 ti->error = "Invalid number of features";
1015 return -EINVAL;
1016 }
1017
1018 argc--;
1019 argv++;
1020 (*args_used)++;
1021
1022 if (num_features > argc) {
1023 ti->error = "Not enough arguments to support feature count";
1024 return -EINVAL;
1025 }
1026
1027 for (i = 0; i < num_features; i++) {
1028 if (!strcmp("handle_errors", argv[0]))
1029 ms->features |= DM_RAID1_HANDLE_ERRORS;
1030 else if (!strcmp("keep_log", argv[0]))
1031 ms->features |= DM_RAID1_KEEP_LOG;
1032 else {
1033 ti->error = "Unrecognised feature requested";
1034 return -EINVAL;
1035 }
1036
1037 argc--;
1038 argv++;
1039 (*args_used)++;
1040 }
1041 if (!errors_handled(ms) && keep_log(ms)) {
1042 ti->error = "keep_log feature requires the handle_errors feature";
1043 return -EINVAL;
1044 }
1045
1046 return 0;
1047}
1048
1049/*
1050 * Construct a mirror mapping:
1051 *
1052 * log_type #log_params <log_params>
1053 * #mirrors [mirror_path offset]{2,}
1054 * [#features <features>]
1055 *
1056 * log_type is "core" or "disk"
1057 * #log_params is between 1 and 3
1058 *
1059 * If present, supported features are "handle_errors" and "keep_log".
1060 */
1061static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1062{
1063 int r;
1064 unsigned int nr_mirrors, m, args_used;
1065 struct mirror_set *ms;
1066 struct dm_dirty_log *dl;
1067 char dummy;
1068
1069 dl = create_dirty_log(ti, argc, argv, &args_used);
1070 if (!dl)
1071 return -EINVAL;
1072
1073 argv += args_used;
1074 argc -= args_used;
1075
1076 if (!argc || sscanf(argv[0], "%u%c", &nr_mirrors, &dummy) != 1 ||
1077 nr_mirrors < 2 || nr_mirrors > MAX_NR_MIRRORS) {
1078 ti->error = "Invalid number of mirrors";
1079 dm_dirty_log_destroy(dl);
1080 return -EINVAL;
1081 }
1082
1083 argv++, argc--;
1084
1085 if (argc < nr_mirrors * 2) {
1086 ti->error = "Too few mirror arguments";
1087 dm_dirty_log_destroy(dl);
1088 return -EINVAL;
1089 }
1090
1091 ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl);
1092 if (!ms) {
1093 dm_dirty_log_destroy(dl);
1094 return -ENOMEM;
1095 }
1096
1097 /* Get the mirror parameter sets */
1098 for (m = 0; m < nr_mirrors; m++) {
1099 r = get_mirror(ms, ti, m, argv);
1100 if (r) {
1101 free_context(ms, ti, m);
1102 return r;
1103 }
1104 argv += 2;
1105 argc -= 2;
1106 }
1107
1108 ti->private = ms;
1109
1110 r = dm_set_target_max_io_len(ti, dm_rh_get_region_size(ms->rh));
1111 if (r)
1112 goto err_free_context;
1113
1114 ti->num_flush_bios = 1;
1115 ti->num_discard_bios = 1;
1116 ti->per_io_data_size = sizeof(struct dm_raid1_bio_record);
1117
1118 ms->kmirrord_wq = alloc_workqueue("kmirrord", WQ_MEM_RECLAIM, 0);
1119 if (!ms->kmirrord_wq) {
1120 DMERR("couldn't start kmirrord");
1121 r = -ENOMEM;
1122 goto err_free_context;
1123 }
1124 INIT_WORK(&ms->kmirrord_work, do_mirror);
1125 timer_setup(&ms->timer, delayed_wake_fn, 0);
1126 ms->timer_pending = 0;
1127 INIT_WORK(&ms->trigger_event, trigger_event);
1128
1129 r = parse_features(ms, argc, argv, &args_used);
1130 if (r)
1131 goto err_destroy_wq;
1132
1133 argv += args_used;
1134 argc -= args_used;
1135
1136 /*
1137 * Any read-balancing addition depends on the
1138 * DM_RAID1_HANDLE_ERRORS flag being present.
1139 * This is because the decision to balance depends
1140 * on the sync state of a region. If the above
1141 * flag is not present, we ignore errors; and
1142 * the sync state may be inaccurate.
1143 */
1144
1145 if (argc) {
1146 ti->error = "Too many mirror arguments";
1147 r = -EINVAL;
1148 goto err_destroy_wq;
1149 }
1150
1151 ms->kcopyd_client = dm_kcopyd_client_create(&dm_kcopyd_throttle);
1152 if (IS_ERR(ms->kcopyd_client)) {
1153 r = PTR_ERR(ms->kcopyd_client);
1154 goto err_destroy_wq;
1155 }
1156
1157 wakeup_mirrord(ms);
1158 return 0;
1159
1160err_destroy_wq:
1161 destroy_workqueue(ms->kmirrord_wq);
1162err_free_context:
1163 free_context(ms, ti, ms->nr_mirrors);
1164 return r;
1165}
1166
1167static void mirror_dtr(struct dm_target *ti)
1168{
1169 struct mirror_set *ms = (struct mirror_set *) ti->private;
1170
1171 del_timer_sync(&ms->timer);
1172 flush_workqueue(ms->kmirrord_wq);
1173 flush_work(&ms->trigger_event);
1174 dm_kcopyd_client_destroy(ms->kcopyd_client);
1175 destroy_workqueue(ms->kmirrord_wq);
1176 free_context(ms, ti, ms->nr_mirrors);
1177}
1178
1179/*
1180 * Mirror mapping function
1181 */
1182static int mirror_map(struct dm_target *ti, struct bio *bio)
1183{
1184 int r, rw = bio_data_dir(bio);
1185 struct mirror *m;
1186 struct mirror_set *ms = ti->private;
1187 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1188 struct dm_raid1_bio_record *bio_record =
1189 dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
1190
1191 bio_record->details.bi_bdev = NULL;
1192
1193 if (rw == WRITE) {
1194 /* Save region for mirror_end_io() handler */
1195 bio_record->write_region = dm_rh_bio_to_region(ms->rh, bio);
1196 queue_bio(ms, bio, rw);
1197 return DM_MAPIO_SUBMITTED;
1198 }
1199
1200 r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0);
1201 if (r < 0 && r != -EWOULDBLOCK)
1202 return DM_MAPIO_KILL;
1203
1204 /*
1205 * If region is not in-sync queue the bio.
1206 */
1207 if (!r || (r == -EWOULDBLOCK)) {
1208 if (bio->bi_opf & REQ_RAHEAD)
1209 return DM_MAPIO_KILL;
1210
1211 queue_bio(ms, bio, rw);
1212 return DM_MAPIO_SUBMITTED;
1213 }
1214
1215 /*
1216 * The region is in-sync and we can perform reads directly.
1217 * Store enough information so we can retry if it fails.
1218 */
1219 m = choose_mirror(ms, bio->bi_iter.bi_sector);
1220 if (unlikely(!m))
1221 return DM_MAPIO_KILL;
1222
1223 dm_bio_record(&bio_record->details, bio);
1224 bio_record->m = m;
1225
1226 map_bio(m, bio);
1227
1228 return DM_MAPIO_REMAPPED;
1229}
1230
1231static int mirror_end_io(struct dm_target *ti, struct bio *bio,
1232 blk_status_t *error)
1233{
1234 int rw = bio_data_dir(bio);
1235 struct mirror_set *ms = (struct mirror_set *) ti->private;
1236 struct mirror *m = NULL;
1237 struct dm_bio_details *bd = NULL;
1238 struct dm_raid1_bio_record *bio_record =
1239 dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
1240
1241 /*
1242 * We need to dec pending if this was a write.
1243 */
1244 if (rw == WRITE) {
1245 if (!(bio->bi_opf & REQ_PREFLUSH) &&
1246 bio_op(bio) != REQ_OP_DISCARD)
1247 dm_rh_dec(ms->rh, bio_record->write_region);
1248 return DM_ENDIO_DONE;
1249 }
1250
1251 if (*error == BLK_STS_NOTSUPP)
1252 goto out;
1253
1254 if (bio->bi_opf & REQ_RAHEAD)
1255 goto out;
1256
1257 if (unlikely(*error)) {
1258 if (!bio_record->details.bi_bdev) {
1259 /*
1260 * There wasn't enough memory to record necessary
1261 * information for a retry or there was no other
1262 * mirror in-sync.
1263 */
1264 DMERR_LIMIT("Mirror read failed.");
1265 return DM_ENDIO_DONE;
1266 }
1267
1268 m = bio_record->m;
1269
1270 DMERR("Mirror read failed from %s. Trying alternative device.",
1271 m->dev->name);
1272
1273 fail_mirror(m, DM_RAID1_READ_ERROR);
1274
1275 /*
1276 * A failed read is requeued for another attempt using an intact
1277 * mirror.
1278 */
1279 if (default_ok(m) || mirror_available(ms, bio)) {
1280 bd = &bio_record->details;
1281
1282 dm_bio_restore(bd, bio);
1283 bio_record->details.bi_bdev = NULL;
1284 bio->bi_status = 0;
1285
1286 queue_bio(ms, bio, rw);
1287 return DM_ENDIO_INCOMPLETE;
1288 }
1289 DMERR("All replicated volumes dead, failing I/O");
1290 }
1291
1292out:
1293 bio_record->details.bi_bdev = NULL;
1294
1295 return DM_ENDIO_DONE;
1296}
1297
1298static void mirror_presuspend(struct dm_target *ti)
1299{
1300 struct mirror_set *ms = (struct mirror_set *) ti->private;
1301 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1302
1303 struct bio_list holds;
1304 struct bio *bio;
1305
1306 atomic_set(&ms->suspend, 1);
1307
1308 /*
1309 * Process bios in the hold list to start recovery waiting
1310 * for bios in the hold list. After the process, no bio has
1311 * a chance to be added in the hold list because ms->suspend
1312 * is set.
1313 */
1314 spin_lock_irq(&ms->lock);
1315 holds = ms->holds;
1316 bio_list_init(&ms->holds);
1317 spin_unlock_irq(&ms->lock);
1318
1319 while ((bio = bio_list_pop(&holds)))
1320 hold_bio(ms, bio);
1321
1322 /*
1323 * We must finish up all the work that we've
1324 * generated (i.e. recovery work).
1325 */
1326 dm_rh_stop_recovery(ms->rh);
1327
1328 wait_event(_kmirrord_recovery_stopped,
1329 !dm_rh_recovery_in_flight(ms->rh));
1330
1331 if (log->type->presuspend && log->type->presuspend(log))
1332 /* FIXME: need better error handling */
1333 DMWARN("log presuspend failed");
1334
1335 /*
1336 * Now that recovery is complete/stopped and the
1337 * delayed bios are queued, we need to wait for
1338 * the worker thread to complete. This way,
1339 * we know that all of our I/O has been pushed.
1340 */
1341 flush_workqueue(ms->kmirrord_wq);
1342}
1343
1344static void mirror_postsuspend(struct dm_target *ti)
1345{
1346 struct mirror_set *ms = ti->private;
1347 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1348
1349 if (log->type->postsuspend && log->type->postsuspend(log))
1350 /* FIXME: need better error handling */
1351 DMWARN("log postsuspend failed");
1352}
1353
1354static void mirror_resume(struct dm_target *ti)
1355{
1356 struct mirror_set *ms = ti->private;
1357 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1358
1359 atomic_set(&ms->suspend, 0);
1360 if (log->type->resume && log->type->resume(log))
1361 /* FIXME: need better error handling */
1362 DMWARN("log resume failed");
1363 dm_rh_start_recovery(ms->rh);
1364}
1365
1366/*
1367 * device_status_char
1368 * @m: mirror device/leg we want the status of
1369 *
1370 * We return one character representing the most severe error
1371 * we have encountered.
1372 * A => Alive - No failures
1373 * D => Dead - A write failure occurred leaving mirror out-of-sync
1374 * S => Sync - A sychronization failure occurred, mirror out-of-sync
1375 * R => Read - A read failure occurred, mirror data unaffected
1376 *
1377 * Returns: <char>
1378 */
1379static char device_status_char(struct mirror *m)
1380{
1381 if (!atomic_read(&(m->error_count)))
1382 return 'A';
1383
1384 return (test_bit(DM_RAID1_FLUSH_ERROR, &(m->error_type))) ? 'F' :
1385 (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' :
1386 (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' :
1387 (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U';
1388}
1389
1390
1391static void mirror_status(struct dm_target *ti, status_type_t type,
1392 unsigned status_flags, char *result, unsigned maxlen)
1393{
1394 unsigned int m, sz = 0;
1395 int num_feature_args = 0;
1396 struct mirror_set *ms = (struct mirror_set *) ti->private;
1397 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1398 char buffer[MAX_NR_MIRRORS + 1];
1399
1400 switch (type) {
1401 case STATUSTYPE_INFO:
1402 DMEMIT("%d ", ms->nr_mirrors);
1403 for (m = 0; m < ms->nr_mirrors; m++) {
1404 DMEMIT("%s ", ms->mirror[m].dev->name);
1405 buffer[m] = device_status_char(&(ms->mirror[m]));
1406 }
1407 buffer[m] = '\0';
1408
1409 DMEMIT("%llu/%llu 1 %s ",
1410 (unsigned long long)log->type->get_sync_count(log),
1411 (unsigned long long)ms->nr_regions, buffer);
1412
1413 sz += log->type->status(log, type, result+sz, maxlen-sz);
1414
1415 break;
1416
1417 case STATUSTYPE_TABLE:
1418 sz = log->type->status(log, type, result, maxlen);
1419
1420 DMEMIT("%d", ms->nr_mirrors);
1421 for (m = 0; m < ms->nr_mirrors; m++)
1422 DMEMIT(" %s %llu", ms->mirror[m].dev->name,
1423 (unsigned long long)ms->mirror[m].offset);
1424
1425 num_feature_args += !!errors_handled(ms);
1426 num_feature_args += !!keep_log(ms);
1427 if (num_feature_args) {
1428 DMEMIT(" %d", num_feature_args);
1429 if (errors_handled(ms))
1430 DMEMIT(" handle_errors");
1431 if (keep_log(ms))
1432 DMEMIT(" keep_log");
1433 }
1434
1435 break;
1436
1437 case STATUSTYPE_IMA:
1438 DMEMIT_TARGET_NAME_VERSION(ti->type);
1439 DMEMIT(",nr_mirrors=%d", ms->nr_mirrors);
1440 for (m = 0; m < ms->nr_mirrors; m++) {
1441 DMEMIT(",mirror_device_%d=%s", m, ms->mirror[m].dev->name);
1442 DMEMIT(",mirror_device_%d_status=%c",
1443 m, device_status_char(&(ms->mirror[m])));
1444 }
1445
1446 DMEMIT(",handle_errors=%c", errors_handled(ms) ? 'y' : 'n');
1447 DMEMIT(",keep_log=%c", keep_log(ms) ? 'y' : 'n');
1448
1449 DMEMIT(",log_type_status=");
1450 sz += log->type->status(log, type, result+sz, maxlen-sz);
1451 DMEMIT(";");
1452 break;
1453 }
1454}
1455
1456static int mirror_iterate_devices(struct dm_target *ti,
1457 iterate_devices_callout_fn fn, void *data)
1458{
1459 struct mirror_set *ms = ti->private;
1460 int ret = 0;
1461 unsigned i;
1462
1463 for (i = 0; !ret && i < ms->nr_mirrors; i++)
1464 ret = fn(ti, ms->mirror[i].dev,
1465 ms->mirror[i].offset, ti->len, data);
1466
1467 return ret;
1468}
1469
1470static struct target_type mirror_target = {
1471 .name = "mirror",
1472 .version = {1, 14, 0},
1473 .module = THIS_MODULE,
1474 .ctr = mirror_ctr,
1475 .dtr = mirror_dtr,
1476 .map = mirror_map,
1477 .end_io = mirror_end_io,
1478 .presuspend = mirror_presuspend,
1479 .postsuspend = mirror_postsuspend,
1480 .resume = mirror_resume,
1481 .status = mirror_status,
1482 .iterate_devices = mirror_iterate_devices,
1483};
1484
1485static int __init dm_mirror_init(void)
1486{
1487 int r;
1488
1489 r = dm_register_target(&mirror_target);
1490 if (r < 0) {
1491 DMERR("Failed to register mirror target");
1492 goto bad_target;
1493 }
1494
1495 return 0;
1496
1497bad_target:
1498 return r;
1499}
1500
1501static void __exit dm_mirror_exit(void)
1502{
1503 dm_unregister_target(&mirror_target);
1504}
1505
1506/* Module hooks */
1507module_init(dm_mirror_init);
1508module_exit(dm_mirror_exit);
1509
1510MODULE_DESCRIPTION(DM_NAME " mirror target");
1511MODULE_AUTHOR("Joe Thornber");
1512MODULE_LICENSE("GPL");
1/*
2 * Copyright (C) 2003 Sistina Software Limited.
3 * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm-bio-record.h"
9
10#include <linux/init.h>
11#include <linux/mempool.h>
12#include <linux/module.h>
13#include <linux/pagemap.h>
14#include <linux/slab.h>
15#include <linux/workqueue.h>
16#include <linux/device-mapper.h>
17#include <linux/dm-io.h>
18#include <linux/dm-dirty-log.h>
19#include <linux/dm-kcopyd.h>
20#include <linux/dm-region-hash.h>
21
22#define DM_MSG_PREFIX "raid1"
23
24#define MAX_RECOVERY 1 /* Maximum number of regions recovered in parallel. */
25
26#define DM_RAID1_HANDLE_ERRORS 0x01
27#define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS)
28
29static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped);
30
31/*-----------------------------------------------------------------
32 * Mirror set structures.
33 *---------------------------------------------------------------*/
34enum dm_raid1_error {
35 DM_RAID1_WRITE_ERROR,
36 DM_RAID1_FLUSH_ERROR,
37 DM_RAID1_SYNC_ERROR,
38 DM_RAID1_READ_ERROR
39};
40
41struct mirror {
42 struct mirror_set *ms;
43 atomic_t error_count;
44 unsigned long error_type;
45 struct dm_dev *dev;
46 sector_t offset;
47};
48
49struct mirror_set {
50 struct dm_target *ti;
51 struct list_head list;
52
53 uint64_t features;
54
55 spinlock_t lock; /* protects the lists */
56 struct bio_list reads;
57 struct bio_list writes;
58 struct bio_list failures;
59 struct bio_list holds; /* bios are waiting until suspend */
60
61 struct dm_region_hash *rh;
62 struct dm_kcopyd_client *kcopyd_client;
63 struct dm_io_client *io_client;
64
65 /* recovery */
66 region_t nr_regions;
67 int in_sync;
68 int log_failure;
69 int leg_failure;
70 atomic_t suspend;
71
72 atomic_t default_mirror; /* Default mirror */
73
74 struct workqueue_struct *kmirrord_wq;
75 struct work_struct kmirrord_work;
76 struct timer_list timer;
77 unsigned long timer_pending;
78
79 struct work_struct trigger_event;
80
81 unsigned nr_mirrors;
82 struct mirror mirror[0];
83};
84
85DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(raid1_resync_throttle,
86 "A percentage of time allocated for raid resynchronization");
87
88static void wakeup_mirrord(void *context)
89{
90 struct mirror_set *ms = context;
91
92 queue_work(ms->kmirrord_wq, &ms->kmirrord_work);
93}
94
95static void delayed_wake_fn(unsigned long data)
96{
97 struct mirror_set *ms = (struct mirror_set *) data;
98
99 clear_bit(0, &ms->timer_pending);
100 wakeup_mirrord(ms);
101}
102
103static void delayed_wake(struct mirror_set *ms)
104{
105 if (test_and_set_bit(0, &ms->timer_pending))
106 return;
107
108 ms->timer.expires = jiffies + HZ / 5;
109 ms->timer.data = (unsigned long) ms;
110 ms->timer.function = delayed_wake_fn;
111 add_timer(&ms->timer);
112}
113
114static void wakeup_all_recovery_waiters(void *context)
115{
116 wake_up_all(&_kmirrord_recovery_stopped);
117}
118
119static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw)
120{
121 unsigned long flags;
122 int should_wake = 0;
123 struct bio_list *bl;
124
125 bl = (rw == WRITE) ? &ms->writes : &ms->reads;
126 spin_lock_irqsave(&ms->lock, flags);
127 should_wake = !(bl->head);
128 bio_list_add(bl, bio);
129 spin_unlock_irqrestore(&ms->lock, flags);
130
131 if (should_wake)
132 wakeup_mirrord(ms);
133}
134
135static void dispatch_bios(void *context, struct bio_list *bio_list)
136{
137 struct mirror_set *ms = context;
138 struct bio *bio;
139
140 while ((bio = bio_list_pop(bio_list)))
141 queue_bio(ms, bio, WRITE);
142}
143
144struct dm_raid1_bio_record {
145 struct mirror *m;
146 /* if details->bi_bdev == NULL, details were not saved */
147 struct dm_bio_details details;
148 region_t write_region;
149};
150
151/*
152 * Every mirror should look like this one.
153 */
154#define DEFAULT_MIRROR 0
155
156/*
157 * This is yucky. We squirrel the mirror struct away inside
158 * bi_next for read/write buffers. This is safe since the bh
159 * doesn't get submitted to the lower levels of block layer.
160 */
161static struct mirror *bio_get_m(struct bio *bio)
162{
163 return (struct mirror *) bio->bi_next;
164}
165
166static void bio_set_m(struct bio *bio, struct mirror *m)
167{
168 bio->bi_next = (struct bio *) m;
169}
170
171static struct mirror *get_default_mirror(struct mirror_set *ms)
172{
173 return &ms->mirror[atomic_read(&ms->default_mirror)];
174}
175
176static void set_default_mirror(struct mirror *m)
177{
178 struct mirror_set *ms = m->ms;
179 struct mirror *m0 = &(ms->mirror[0]);
180
181 atomic_set(&ms->default_mirror, m - m0);
182}
183
184static struct mirror *get_valid_mirror(struct mirror_set *ms)
185{
186 struct mirror *m;
187
188 for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++)
189 if (!atomic_read(&m->error_count))
190 return m;
191
192 return NULL;
193}
194
195/* fail_mirror
196 * @m: mirror device to fail
197 * @error_type: one of the enum's, DM_RAID1_*_ERROR
198 *
199 * If errors are being handled, record the type of
200 * error encountered for this device. If this type
201 * of error has already been recorded, we can return;
202 * otherwise, we must signal userspace by triggering
203 * an event. Additionally, if the device is the
204 * primary device, we must choose a new primary, but
205 * only if the mirror is in-sync.
206 *
207 * This function must not block.
208 */
209static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
210{
211 struct mirror_set *ms = m->ms;
212 struct mirror *new;
213
214 ms->leg_failure = 1;
215
216 /*
217 * error_count is used for nothing more than a
218 * simple way to tell if a device has encountered
219 * errors.
220 */
221 atomic_inc(&m->error_count);
222
223 if (test_and_set_bit(error_type, &m->error_type))
224 return;
225
226 if (!errors_handled(ms))
227 return;
228
229 if (m != get_default_mirror(ms))
230 goto out;
231
232 if (!ms->in_sync) {
233 /*
234 * Better to issue requests to same failing device
235 * than to risk returning corrupt data.
236 */
237 DMERR("Primary mirror (%s) failed while out-of-sync: "
238 "Reads may fail.", m->dev->name);
239 goto out;
240 }
241
242 new = get_valid_mirror(ms);
243 if (new)
244 set_default_mirror(new);
245 else
246 DMWARN("All sides of mirror have failed.");
247
248out:
249 schedule_work(&ms->trigger_event);
250}
251
252static int mirror_flush(struct dm_target *ti)
253{
254 struct mirror_set *ms = ti->private;
255 unsigned long error_bits;
256
257 unsigned int i;
258 struct dm_io_region io[ms->nr_mirrors];
259 struct mirror *m;
260 struct dm_io_request io_req = {
261 .bi_rw = WRITE_FLUSH,
262 .mem.type = DM_IO_KMEM,
263 .mem.ptr.addr = NULL,
264 .client = ms->io_client,
265 };
266
267 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) {
268 io[i].bdev = m->dev->bdev;
269 io[i].sector = 0;
270 io[i].count = 0;
271 }
272
273 error_bits = -1;
274 dm_io(&io_req, ms->nr_mirrors, io, &error_bits);
275 if (unlikely(error_bits != 0)) {
276 for (i = 0; i < ms->nr_mirrors; i++)
277 if (test_bit(i, &error_bits))
278 fail_mirror(ms->mirror + i,
279 DM_RAID1_FLUSH_ERROR);
280 return -EIO;
281 }
282
283 return 0;
284}
285
286/*-----------------------------------------------------------------
287 * Recovery.
288 *
289 * When a mirror is first activated we may find that some regions
290 * are in the no-sync state. We have to recover these by
291 * recopying from the default mirror to all the others.
292 *---------------------------------------------------------------*/
293static void recovery_complete(int read_err, unsigned long write_err,
294 void *context)
295{
296 struct dm_region *reg = context;
297 struct mirror_set *ms = dm_rh_region_context(reg);
298 int m, bit = 0;
299
300 if (read_err) {
301 /* Read error means the failure of default mirror. */
302 DMERR_LIMIT("Unable to read primary mirror during recovery");
303 fail_mirror(get_default_mirror(ms), DM_RAID1_SYNC_ERROR);
304 }
305
306 if (write_err) {
307 DMERR_LIMIT("Write error during recovery (error = 0x%lx)",
308 write_err);
309 /*
310 * Bits correspond to devices (excluding default mirror).
311 * The default mirror cannot change during recovery.
312 */
313 for (m = 0; m < ms->nr_mirrors; m++) {
314 if (&ms->mirror[m] == get_default_mirror(ms))
315 continue;
316 if (test_bit(bit, &write_err))
317 fail_mirror(ms->mirror + m,
318 DM_RAID1_SYNC_ERROR);
319 bit++;
320 }
321 }
322
323 dm_rh_recovery_end(reg, !(read_err || write_err));
324}
325
326static int recover(struct mirror_set *ms, struct dm_region *reg)
327{
328 int r;
329 unsigned i;
330 struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest;
331 struct mirror *m;
332 unsigned long flags = 0;
333 region_t key = dm_rh_get_region_key(reg);
334 sector_t region_size = dm_rh_get_region_size(ms->rh);
335
336 /* fill in the source */
337 m = get_default_mirror(ms);
338 from.bdev = m->dev->bdev;
339 from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
340 if (key == (ms->nr_regions - 1)) {
341 /*
342 * The final region may be smaller than
343 * region_size.
344 */
345 from.count = ms->ti->len & (region_size - 1);
346 if (!from.count)
347 from.count = region_size;
348 } else
349 from.count = region_size;
350
351 /* fill in the destinations */
352 for (i = 0, dest = to; i < ms->nr_mirrors; i++) {
353 if (&ms->mirror[i] == get_default_mirror(ms))
354 continue;
355
356 m = ms->mirror + i;
357 dest->bdev = m->dev->bdev;
358 dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
359 dest->count = from.count;
360 dest++;
361 }
362
363 /* hand to kcopyd */
364 if (!errors_handled(ms))
365 set_bit(DM_KCOPYD_IGNORE_ERROR, &flags);
366
367 r = dm_kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to,
368 flags, recovery_complete, reg);
369
370 return r;
371}
372
373static void do_recovery(struct mirror_set *ms)
374{
375 struct dm_region *reg;
376 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
377 int r;
378
379 /*
380 * Start quiescing some regions.
381 */
382 dm_rh_recovery_prepare(ms->rh);
383
384 /*
385 * Copy any already quiesced regions.
386 */
387 while ((reg = dm_rh_recovery_start(ms->rh))) {
388 r = recover(ms, reg);
389 if (r)
390 dm_rh_recovery_end(reg, 0);
391 }
392
393 /*
394 * Update the in sync flag.
395 */
396 if (!ms->in_sync &&
397 (log->type->get_sync_count(log) == ms->nr_regions)) {
398 /* the sync is complete */
399 dm_table_event(ms->ti->table);
400 ms->in_sync = 1;
401 }
402}
403
404/*-----------------------------------------------------------------
405 * Reads
406 *---------------------------------------------------------------*/
407static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector)
408{
409 struct mirror *m = get_default_mirror(ms);
410
411 do {
412 if (likely(!atomic_read(&m->error_count)))
413 return m;
414
415 if (m-- == ms->mirror)
416 m += ms->nr_mirrors;
417 } while (m != get_default_mirror(ms));
418
419 return NULL;
420}
421
422static int default_ok(struct mirror *m)
423{
424 struct mirror *default_mirror = get_default_mirror(m->ms);
425
426 return !atomic_read(&default_mirror->error_count);
427}
428
429static int mirror_available(struct mirror_set *ms, struct bio *bio)
430{
431 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
432 region_t region = dm_rh_bio_to_region(ms->rh, bio);
433
434 if (log->type->in_sync(log, region, 0))
435 return choose_mirror(ms, bio->bi_iter.bi_sector) ? 1 : 0;
436
437 return 0;
438}
439
440/*
441 * remap a buffer to a particular mirror.
442 */
443static sector_t map_sector(struct mirror *m, struct bio *bio)
444{
445 if (unlikely(!bio->bi_iter.bi_size))
446 return 0;
447 return m->offset + dm_target_offset(m->ms->ti, bio->bi_iter.bi_sector);
448}
449
450static void map_bio(struct mirror *m, struct bio *bio)
451{
452 bio->bi_bdev = m->dev->bdev;
453 bio->bi_iter.bi_sector = map_sector(m, bio);
454}
455
456static void map_region(struct dm_io_region *io, struct mirror *m,
457 struct bio *bio)
458{
459 io->bdev = m->dev->bdev;
460 io->sector = map_sector(m, bio);
461 io->count = bio_sectors(bio);
462}
463
464static void hold_bio(struct mirror_set *ms, struct bio *bio)
465{
466 /*
467 * Lock is required to avoid race condition during suspend
468 * process.
469 */
470 spin_lock_irq(&ms->lock);
471
472 if (atomic_read(&ms->suspend)) {
473 spin_unlock_irq(&ms->lock);
474
475 /*
476 * If device is suspended, complete the bio.
477 */
478 if (dm_noflush_suspending(ms->ti))
479 bio_endio(bio, DM_ENDIO_REQUEUE);
480 else
481 bio_endio(bio, -EIO);
482 return;
483 }
484
485 /*
486 * Hold bio until the suspend is complete.
487 */
488 bio_list_add(&ms->holds, bio);
489 spin_unlock_irq(&ms->lock);
490}
491
492/*-----------------------------------------------------------------
493 * Reads
494 *---------------------------------------------------------------*/
495static void read_callback(unsigned long error, void *context)
496{
497 struct bio *bio = context;
498 struct mirror *m;
499
500 m = bio_get_m(bio);
501 bio_set_m(bio, NULL);
502
503 if (likely(!error)) {
504 bio_endio(bio, 0);
505 return;
506 }
507
508 fail_mirror(m, DM_RAID1_READ_ERROR);
509
510 if (likely(default_ok(m)) || mirror_available(m->ms, bio)) {
511 DMWARN_LIMIT("Read failure on mirror device %s. "
512 "Trying alternative device.",
513 m->dev->name);
514 queue_bio(m->ms, bio, bio_rw(bio));
515 return;
516 }
517
518 DMERR_LIMIT("Read failure on mirror device %s. Failing I/O.",
519 m->dev->name);
520 bio_endio(bio, -EIO);
521}
522
523/* Asynchronous read. */
524static void read_async_bio(struct mirror *m, struct bio *bio)
525{
526 struct dm_io_region io;
527 struct dm_io_request io_req = {
528 .bi_rw = READ,
529 .mem.type = DM_IO_BIO,
530 .mem.ptr.bio = bio,
531 .notify.fn = read_callback,
532 .notify.context = bio,
533 .client = m->ms->io_client,
534 };
535
536 map_region(&io, m, bio);
537 bio_set_m(bio, m);
538 BUG_ON(dm_io(&io_req, 1, &io, NULL));
539}
540
541static inline int region_in_sync(struct mirror_set *ms, region_t region,
542 int may_block)
543{
544 int state = dm_rh_get_state(ms->rh, region, may_block);
545 return state == DM_RH_CLEAN || state == DM_RH_DIRTY;
546}
547
548static void do_reads(struct mirror_set *ms, struct bio_list *reads)
549{
550 region_t region;
551 struct bio *bio;
552 struct mirror *m;
553
554 while ((bio = bio_list_pop(reads))) {
555 region = dm_rh_bio_to_region(ms->rh, bio);
556 m = get_default_mirror(ms);
557
558 /*
559 * We can only read balance if the region is in sync.
560 */
561 if (likely(region_in_sync(ms, region, 1)))
562 m = choose_mirror(ms, bio->bi_iter.bi_sector);
563 else if (m && atomic_read(&m->error_count))
564 m = NULL;
565
566 if (likely(m))
567 read_async_bio(m, bio);
568 else
569 bio_endio(bio, -EIO);
570 }
571}
572
573/*-----------------------------------------------------------------
574 * Writes.
575 *
576 * We do different things with the write io depending on the
577 * state of the region that it's in:
578 *
579 * SYNC: increment pending, use kcopyd to write to *all* mirrors
580 * RECOVERING: delay the io until recovery completes
581 * NOSYNC: increment pending, just write to the default mirror
582 *---------------------------------------------------------------*/
583
584
585static void write_callback(unsigned long error, void *context)
586{
587 unsigned i, ret = 0;
588 struct bio *bio = (struct bio *) context;
589 struct mirror_set *ms;
590 int should_wake = 0;
591 unsigned long flags;
592
593 ms = bio_get_m(bio)->ms;
594 bio_set_m(bio, NULL);
595
596 /*
597 * NOTE: We don't decrement the pending count here,
598 * instead it is done by the targets endio function.
599 * This way we handle both writes to SYNC and NOSYNC
600 * regions with the same code.
601 */
602 if (likely(!error)) {
603 bio_endio(bio, ret);
604 return;
605 }
606
607 for (i = 0; i < ms->nr_mirrors; i++)
608 if (test_bit(i, &error))
609 fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR);
610
611 /*
612 * Need to raise event. Since raising
613 * events can block, we need to do it in
614 * the main thread.
615 */
616 spin_lock_irqsave(&ms->lock, flags);
617 if (!ms->failures.head)
618 should_wake = 1;
619 bio_list_add(&ms->failures, bio);
620 spin_unlock_irqrestore(&ms->lock, flags);
621 if (should_wake)
622 wakeup_mirrord(ms);
623}
624
625static void do_write(struct mirror_set *ms, struct bio *bio)
626{
627 unsigned int i;
628 struct dm_io_region io[ms->nr_mirrors], *dest = io;
629 struct mirror *m;
630 struct dm_io_request io_req = {
631 .bi_rw = WRITE | (bio->bi_rw & WRITE_FLUSH_FUA),
632 .mem.type = DM_IO_BIO,
633 .mem.ptr.bio = bio,
634 .notify.fn = write_callback,
635 .notify.context = bio,
636 .client = ms->io_client,
637 };
638
639 if (bio->bi_rw & REQ_DISCARD) {
640 io_req.bi_rw |= REQ_DISCARD;
641 io_req.mem.type = DM_IO_KMEM;
642 io_req.mem.ptr.addr = NULL;
643 }
644
645 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++)
646 map_region(dest++, m, bio);
647
648 /*
649 * Use default mirror because we only need it to retrieve the reference
650 * to the mirror set in write_callback().
651 */
652 bio_set_m(bio, get_default_mirror(ms));
653
654 BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL));
655}
656
657static void do_writes(struct mirror_set *ms, struct bio_list *writes)
658{
659 int state;
660 struct bio *bio;
661 struct bio_list sync, nosync, recover, *this_list = NULL;
662 struct bio_list requeue;
663 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
664 region_t region;
665
666 if (!writes->head)
667 return;
668
669 /*
670 * Classify each write.
671 */
672 bio_list_init(&sync);
673 bio_list_init(&nosync);
674 bio_list_init(&recover);
675 bio_list_init(&requeue);
676
677 while ((bio = bio_list_pop(writes))) {
678 if ((bio->bi_rw & REQ_FLUSH) ||
679 (bio->bi_rw & REQ_DISCARD)) {
680 bio_list_add(&sync, bio);
681 continue;
682 }
683
684 region = dm_rh_bio_to_region(ms->rh, bio);
685
686 if (log->type->is_remote_recovering &&
687 log->type->is_remote_recovering(log, region)) {
688 bio_list_add(&requeue, bio);
689 continue;
690 }
691
692 state = dm_rh_get_state(ms->rh, region, 1);
693 switch (state) {
694 case DM_RH_CLEAN:
695 case DM_RH_DIRTY:
696 this_list = &sync;
697 break;
698
699 case DM_RH_NOSYNC:
700 this_list = &nosync;
701 break;
702
703 case DM_RH_RECOVERING:
704 this_list = &recover;
705 break;
706 }
707
708 bio_list_add(this_list, bio);
709 }
710
711 /*
712 * Add bios that are delayed due to remote recovery
713 * back on to the write queue
714 */
715 if (unlikely(requeue.head)) {
716 spin_lock_irq(&ms->lock);
717 bio_list_merge(&ms->writes, &requeue);
718 spin_unlock_irq(&ms->lock);
719 delayed_wake(ms);
720 }
721
722 /*
723 * Increment the pending counts for any regions that will
724 * be written to (writes to recover regions are going to
725 * be delayed).
726 */
727 dm_rh_inc_pending(ms->rh, &sync);
728 dm_rh_inc_pending(ms->rh, &nosync);
729
730 /*
731 * If the flush fails on a previous call and succeeds here,
732 * we must not reset the log_failure variable. We need
733 * userspace interaction to do that.
734 */
735 ms->log_failure = dm_rh_flush(ms->rh) ? 1 : ms->log_failure;
736
737 /*
738 * Dispatch io.
739 */
740 if (unlikely(ms->log_failure) && errors_handled(ms)) {
741 spin_lock_irq(&ms->lock);
742 bio_list_merge(&ms->failures, &sync);
743 spin_unlock_irq(&ms->lock);
744 wakeup_mirrord(ms);
745 } else
746 while ((bio = bio_list_pop(&sync)))
747 do_write(ms, bio);
748
749 while ((bio = bio_list_pop(&recover)))
750 dm_rh_delay(ms->rh, bio);
751
752 while ((bio = bio_list_pop(&nosync))) {
753 if (unlikely(ms->leg_failure) && errors_handled(ms)) {
754 spin_lock_irq(&ms->lock);
755 bio_list_add(&ms->failures, bio);
756 spin_unlock_irq(&ms->lock);
757 wakeup_mirrord(ms);
758 } else {
759 map_bio(get_default_mirror(ms), bio);
760 generic_make_request(bio);
761 }
762 }
763}
764
765static void do_failures(struct mirror_set *ms, struct bio_list *failures)
766{
767 struct bio *bio;
768
769 if (likely(!failures->head))
770 return;
771
772 /*
773 * If the log has failed, unattempted writes are being
774 * put on the holds list. We can't issue those writes
775 * until a log has been marked, so we must store them.
776 *
777 * If a 'noflush' suspend is in progress, we can requeue
778 * the I/O's to the core. This give userspace a chance
779 * to reconfigure the mirror, at which point the core
780 * will reissue the writes. If the 'noflush' flag is
781 * not set, we have no choice but to return errors.
782 *
783 * Some writes on the failures list may have been
784 * submitted before the log failure and represent a
785 * failure to write to one of the devices. It is ok
786 * for us to treat them the same and requeue them
787 * as well.
788 */
789 while ((bio = bio_list_pop(failures))) {
790 if (!ms->log_failure) {
791 ms->in_sync = 0;
792 dm_rh_mark_nosync(ms->rh, bio);
793 }
794
795 /*
796 * If all the legs are dead, fail the I/O.
797 * If we have been told to handle errors, hold the bio
798 * and wait for userspace to deal with the problem.
799 * Otherwise pretend that the I/O succeeded. (This would
800 * be wrong if the failed leg returned after reboot and
801 * got replicated back to the good legs.)
802 */
803 if (!get_valid_mirror(ms))
804 bio_endio(bio, -EIO);
805 else if (errors_handled(ms))
806 hold_bio(ms, bio);
807 else
808 bio_endio(bio, 0);
809 }
810}
811
812static void trigger_event(struct work_struct *work)
813{
814 struct mirror_set *ms =
815 container_of(work, struct mirror_set, trigger_event);
816
817 dm_table_event(ms->ti->table);
818}
819
820/*-----------------------------------------------------------------
821 * kmirrord
822 *---------------------------------------------------------------*/
823static void do_mirror(struct work_struct *work)
824{
825 struct mirror_set *ms = container_of(work, struct mirror_set,
826 kmirrord_work);
827 struct bio_list reads, writes, failures;
828 unsigned long flags;
829
830 spin_lock_irqsave(&ms->lock, flags);
831 reads = ms->reads;
832 writes = ms->writes;
833 failures = ms->failures;
834 bio_list_init(&ms->reads);
835 bio_list_init(&ms->writes);
836 bio_list_init(&ms->failures);
837 spin_unlock_irqrestore(&ms->lock, flags);
838
839 dm_rh_update_states(ms->rh, errors_handled(ms));
840 do_recovery(ms);
841 do_reads(ms, &reads);
842 do_writes(ms, &writes);
843 do_failures(ms, &failures);
844}
845
846/*-----------------------------------------------------------------
847 * Target functions
848 *---------------------------------------------------------------*/
849static struct mirror_set *alloc_context(unsigned int nr_mirrors,
850 uint32_t region_size,
851 struct dm_target *ti,
852 struct dm_dirty_log *dl)
853{
854 size_t len;
855 struct mirror_set *ms = NULL;
856
857 len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors);
858
859 ms = kzalloc(len, GFP_KERNEL);
860 if (!ms) {
861 ti->error = "Cannot allocate mirror context";
862 return NULL;
863 }
864
865 spin_lock_init(&ms->lock);
866 bio_list_init(&ms->reads);
867 bio_list_init(&ms->writes);
868 bio_list_init(&ms->failures);
869 bio_list_init(&ms->holds);
870
871 ms->ti = ti;
872 ms->nr_mirrors = nr_mirrors;
873 ms->nr_regions = dm_sector_div_up(ti->len, region_size);
874 ms->in_sync = 0;
875 ms->log_failure = 0;
876 ms->leg_failure = 0;
877 atomic_set(&ms->suspend, 0);
878 atomic_set(&ms->default_mirror, DEFAULT_MIRROR);
879
880 ms->io_client = dm_io_client_create();
881 if (IS_ERR(ms->io_client)) {
882 ti->error = "Error creating dm_io client";
883 kfree(ms);
884 return NULL;
885 }
886
887 ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord,
888 wakeup_all_recovery_waiters,
889 ms->ti->begin, MAX_RECOVERY,
890 dl, region_size, ms->nr_regions);
891 if (IS_ERR(ms->rh)) {
892 ti->error = "Error creating dirty region hash";
893 dm_io_client_destroy(ms->io_client);
894 kfree(ms);
895 return NULL;
896 }
897
898 return ms;
899}
900
901static void free_context(struct mirror_set *ms, struct dm_target *ti,
902 unsigned int m)
903{
904 while (m--)
905 dm_put_device(ti, ms->mirror[m].dev);
906
907 dm_io_client_destroy(ms->io_client);
908 dm_region_hash_destroy(ms->rh);
909 kfree(ms);
910}
911
912static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
913 unsigned int mirror, char **argv)
914{
915 unsigned long long offset;
916 char dummy;
917
918 if (sscanf(argv[1], "%llu%c", &offset, &dummy) != 1) {
919 ti->error = "Invalid offset";
920 return -EINVAL;
921 }
922
923 if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
924 &ms->mirror[mirror].dev)) {
925 ti->error = "Device lookup failure";
926 return -ENXIO;
927 }
928
929 ms->mirror[mirror].ms = ms;
930 atomic_set(&(ms->mirror[mirror].error_count), 0);
931 ms->mirror[mirror].error_type = 0;
932 ms->mirror[mirror].offset = offset;
933
934 return 0;
935}
936
937/*
938 * Create dirty log: log_type #log_params <log_params>
939 */
940static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
941 unsigned argc, char **argv,
942 unsigned *args_used)
943{
944 unsigned param_count;
945 struct dm_dirty_log *dl;
946 char dummy;
947
948 if (argc < 2) {
949 ti->error = "Insufficient mirror log arguments";
950 return NULL;
951 }
952
953 if (sscanf(argv[1], "%u%c", ¶m_count, &dummy) != 1) {
954 ti->error = "Invalid mirror log argument count";
955 return NULL;
956 }
957
958 *args_used = 2 + param_count;
959
960 if (argc < *args_used) {
961 ti->error = "Insufficient mirror log arguments";
962 return NULL;
963 }
964
965 dl = dm_dirty_log_create(argv[0], ti, mirror_flush, param_count,
966 argv + 2);
967 if (!dl) {
968 ti->error = "Error creating mirror dirty log";
969 return NULL;
970 }
971
972 return dl;
973}
974
975static int parse_features(struct mirror_set *ms, unsigned argc, char **argv,
976 unsigned *args_used)
977{
978 unsigned num_features;
979 struct dm_target *ti = ms->ti;
980 char dummy;
981
982 *args_used = 0;
983
984 if (!argc)
985 return 0;
986
987 if (sscanf(argv[0], "%u%c", &num_features, &dummy) != 1) {
988 ti->error = "Invalid number of features";
989 return -EINVAL;
990 }
991
992 argc--;
993 argv++;
994 (*args_used)++;
995
996 if (num_features > argc) {
997 ti->error = "Not enough arguments to support feature count";
998 return -EINVAL;
999 }
1000
1001 if (!strcmp("handle_errors", argv[0]))
1002 ms->features |= DM_RAID1_HANDLE_ERRORS;
1003 else {
1004 ti->error = "Unrecognised feature requested";
1005 return -EINVAL;
1006 }
1007
1008 (*args_used)++;
1009
1010 return 0;
1011}
1012
1013/*
1014 * Construct a mirror mapping:
1015 *
1016 * log_type #log_params <log_params>
1017 * #mirrors [mirror_path offset]{2,}
1018 * [#features <features>]
1019 *
1020 * log_type is "core" or "disk"
1021 * #log_params is between 1 and 3
1022 *
1023 * If present, features must be "handle_errors".
1024 */
1025static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1026{
1027 int r;
1028 unsigned int nr_mirrors, m, args_used;
1029 struct mirror_set *ms;
1030 struct dm_dirty_log *dl;
1031 char dummy;
1032
1033 dl = create_dirty_log(ti, argc, argv, &args_used);
1034 if (!dl)
1035 return -EINVAL;
1036
1037 argv += args_used;
1038 argc -= args_used;
1039
1040 if (!argc || sscanf(argv[0], "%u%c", &nr_mirrors, &dummy) != 1 ||
1041 nr_mirrors < 2 || nr_mirrors > DM_KCOPYD_MAX_REGIONS + 1) {
1042 ti->error = "Invalid number of mirrors";
1043 dm_dirty_log_destroy(dl);
1044 return -EINVAL;
1045 }
1046
1047 argv++, argc--;
1048
1049 if (argc < nr_mirrors * 2) {
1050 ti->error = "Too few mirror arguments";
1051 dm_dirty_log_destroy(dl);
1052 return -EINVAL;
1053 }
1054
1055 ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl);
1056 if (!ms) {
1057 dm_dirty_log_destroy(dl);
1058 return -ENOMEM;
1059 }
1060
1061 /* Get the mirror parameter sets */
1062 for (m = 0; m < nr_mirrors; m++) {
1063 r = get_mirror(ms, ti, m, argv);
1064 if (r) {
1065 free_context(ms, ti, m);
1066 return r;
1067 }
1068 argv += 2;
1069 argc -= 2;
1070 }
1071
1072 ti->private = ms;
1073
1074 r = dm_set_target_max_io_len(ti, dm_rh_get_region_size(ms->rh));
1075 if (r)
1076 goto err_free_context;
1077
1078 ti->num_flush_bios = 1;
1079 ti->num_discard_bios = 1;
1080 ti->per_bio_data_size = sizeof(struct dm_raid1_bio_record);
1081 ti->discard_zeroes_data_unsupported = true;
1082
1083 ms->kmirrord_wq = alloc_workqueue("kmirrord", WQ_MEM_RECLAIM, 0);
1084 if (!ms->kmirrord_wq) {
1085 DMERR("couldn't start kmirrord");
1086 r = -ENOMEM;
1087 goto err_free_context;
1088 }
1089 INIT_WORK(&ms->kmirrord_work, do_mirror);
1090 init_timer(&ms->timer);
1091 ms->timer_pending = 0;
1092 INIT_WORK(&ms->trigger_event, trigger_event);
1093
1094 r = parse_features(ms, argc, argv, &args_used);
1095 if (r)
1096 goto err_destroy_wq;
1097
1098 argv += args_used;
1099 argc -= args_used;
1100
1101 /*
1102 * Any read-balancing addition depends on the
1103 * DM_RAID1_HANDLE_ERRORS flag being present.
1104 * This is because the decision to balance depends
1105 * on the sync state of a region. If the above
1106 * flag is not present, we ignore errors; and
1107 * the sync state may be inaccurate.
1108 */
1109
1110 if (argc) {
1111 ti->error = "Too many mirror arguments";
1112 r = -EINVAL;
1113 goto err_destroy_wq;
1114 }
1115
1116 ms->kcopyd_client = dm_kcopyd_client_create(&dm_kcopyd_throttle);
1117 if (IS_ERR(ms->kcopyd_client)) {
1118 r = PTR_ERR(ms->kcopyd_client);
1119 goto err_destroy_wq;
1120 }
1121
1122 wakeup_mirrord(ms);
1123 return 0;
1124
1125err_destroy_wq:
1126 destroy_workqueue(ms->kmirrord_wq);
1127err_free_context:
1128 free_context(ms, ti, ms->nr_mirrors);
1129 return r;
1130}
1131
1132static void mirror_dtr(struct dm_target *ti)
1133{
1134 struct mirror_set *ms = (struct mirror_set *) ti->private;
1135
1136 del_timer_sync(&ms->timer);
1137 flush_workqueue(ms->kmirrord_wq);
1138 flush_work(&ms->trigger_event);
1139 dm_kcopyd_client_destroy(ms->kcopyd_client);
1140 destroy_workqueue(ms->kmirrord_wq);
1141 free_context(ms, ti, ms->nr_mirrors);
1142}
1143
1144/*
1145 * Mirror mapping function
1146 */
1147static int mirror_map(struct dm_target *ti, struct bio *bio)
1148{
1149 int r, rw = bio_rw(bio);
1150 struct mirror *m;
1151 struct mirror_set *ms = ti->private;
1152 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1153 struct dm_raid1_bio_record *bio_record =
1154 dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
1155
1156 bio_record->details.bi_bdev = NULL;
1157
1158 if (rw == WRITE) {
1159 /* Save region for mirror_end_io() handler */
1160 bio_record->write_region = dm_rh_bio_to_region(ms->rh, bio);
1161 queue_bio(ms, bio, rw);
1162 return DM_MAPIO_SUBMITTED;
1163 }
1164
1165 r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0);
1166 if (r < 0 && r != -EWOULDBLOCK)
1167 return r;
1168
1169 /*
1170 * If region is not in-sync queue the bio.
1171 */
1172 if (!r || (r == -EWOULDBLOCK)) {
1173 if (rw == READA)
1174 return -EWOULDBLOCK;
1175
1176 queue_bio(ms, bio, rw);
1177 return DM_MAPIO_SUBMITTED;
1178 }
1179
1180 /*
1181 * The region is in-sync and we can perform reads directly.
1182 * Store enough information so we can retry if it fails.
1183 */
1184 m = choose_mirror(ms, bio->bi_iter.bi_sector);
1185 if (unlikely(!m))
1186 return -EIO;
1187
1188 dm_bio_record(&bio_record->details, bio);
1189 bio_record->m = m;
1190
1191 map_bio(m, bio);
1192
1193 return DM_MAPIO_REMAPPED;
1194}
1195
1196static int mirror_end_io(struct dm_target *ti, struct bio *bio, int error)
1197{
1198 int rw = bio_rw(bio);
1199 struct mirror_set *ms = (struct mirror_set *) ti->private;
1200 struct mirror *m = NULL;
1201 struct dm_bio_details *bd = NULL;
1202 struct dm_raid1_bio_record *bio_record =
1203 dm_per_bio_data(bio, sizeof(struct dm_raid1_bio_record));
1204
1205 /*
1206 * We need to dec pending if this was a write.
1207 */
1208 if (rw == WRITE) {
1209 if (!(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD)))
1210 dm_rh_dec(ms->rh, bio_record->write_region);
1211 return error;
1212 }
1213
1214 if (error == -EOPNOTSUPP)
1215 goto out;
1216
1217 if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
1218 goto out;
1219
1220 if (unlikely(error)) {
1221 if (!bio_record->details.bi_bdev) {
1222 /*
1223 * There wasn't enough memory to record necessary
1224 * information for a retry or there was no other
1225 * mirror in-sync.
1226 */
1227 DMERR_LIMIT("Mirror read failed.");
1228 return -EIO;
1229 }
1230
1231 m = bio_record->m;
1232
1233 DMERR("Mirror read failed from %s. Trying alternative device.",
1234 m->dev->name);
1235
1236 fail_mirror(m, DM_RAID1_READ_ERROR);
1237
1238 /*
1239 * A failed read is requeued for another attempt using an intact
1240 * mirror.
1241 */
1242 if (default_ok(m) || mirror_available(ms, bio)) {
1243 bd = &bio_record->details;
1244
1245 dm_bio_restore(bd, bio);
1246 bio_record->details.bi_bdev = NULL;
1247
1248 atomic_inc(&bio->bi_remaining);
1249
1250 queue_bio(ms, bio, rw);
1251 return DM_ENDIO_INCOMPLETE;
1252 }
1253 DMERR("All replicated volumes dead, failing I/O");
1254 }
1255
1256out:
1257 bio_record->details.bi_bdev = NULL;
1258
1259 return error;
1260}
1261
1262static void mirror_presuspend(struct dm_target *ti)
1263{
1264 struct mirror_set *ms = (struct mirror_set *) ti->private;
1265 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1266
1267 struct bio_list holds;
1268 struct bio *bio;
1269
1270 atomic_set(&ms->suspend, 1);
1271
1272 /*
1273 * Process bios in the hold list to start recovery waiting
1274 * for bios in the hold list. After the process, no bio has
1275 * a chance to be added in the hold list because ms->suspend
1276 * is set.
1277 */
1278 spin_lock_irq(&ms->lock);
1279 holds = ms->holds;
1280 bio_list_init(&ms->holds);
1281 spin_unlock_irq(&ms->lock);
1282
1283 while ((bio = bio_list_pop(&holds)))
1284 hold_bio(ms, bio);
1285
1286 /*
1287 * We must finish up all the work that we've
1288 * generated (i.e. recovery work).
1289 */
1290 dm_rh_stop_recovery(ms->rh);
1291
1292 wait_event(_kmirrord_recovery_stopped,
1293 !dm_rh_recovery_in_flight(ms->rh));
1294
1295 if (log->type->presuspend && log->type->presuspend(log))
1296 /* FIXME: need better error handling */
1297 DMWARN("log presuspend failed");
1298
1299 /*
1300 * Now that recovery is complete/stopped and the
1301 * delayed bios are queued, we need to wait for
1302 * the worker thread to complete. This way,
1303 * we know that all of our I/O has been pushed.
1304 */
1305 flush_workqueue(ms->kmirrord_wq);
1306}
1307
1308static void mirror_postsuspend(struct dm_target *ti)
1309{
1310 struct mirror_set *ms = ti->private;
1311 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1312
1313 if (log->type->postsuspend && log->type->postsuspend(log))
1314 /* FIXME: need better error handling */
1315 DMWARN("log postsuspend failed");
1316}
1317
1318static void mirror_resume(struct dm_target *ti)
1319{
1320 struct mirror_set *ms = ti->private;
1321 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1322
1323 atomic_set(&ms->suspend, 0);
1324 if (log->type->resume && log->type->resume(log))
1325 /* FIXME: need better error handling */
1326 DMWARN("log resume failed");
1327 dm_rh_start_recovery(ms->rh);
1328}
1329
1330/*
1331 * device_status_char
1332 * @m: mirror device/leg we want the status of
1333 *
1334 * We return one character representing the most severe error
1335 * we have encountered.
1336 * A => Alive - No failures
1337 * D => Dead - A write failure occurred leaving mirror out-of-sync
1338 * S => Sync - A sychronization failure occurred, mirror out-of-sync
1339 * R => Read - A read failure occurred, mirror data unaffected
1340 *
1341 * Returns: <char>
1342 */
1343static char device_status_char(struct mirror *m)
1344{
1345 if (!atomic_read(&(m->error_count)))
1346 return 'A';
1347
1348 return (test_bit(DM_RAID1_FLUSH_ERROR, &(m->error_type))) ? 'F' :
1349 (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' :
1350 (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' :
1351 (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U';
1352}
1353
1354
1355static void mirror_status(struct dm_target *ti, status_type_t type,
1356 unsigned status_flags, char *result, unsigned maxlen)
1357{
1358 unsigned int m, sz = 0;
1359 struct mirror_set *ms = (struct mirror_set *) ti->private;
1360 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1361 char buffer[ms->nr_mirrors + 1];
1362
1363 switch (type) {
1364 case STATUSTYPE_INFO:
1365 DMEMIT("%d ", ms->nr_mirrors);
1366 for (m = 0; m < ms->nr_mirrors; m++) {
1367 DMEMIT("%s ", ms->mirror[m].dev->name);
1368 buffer[m] = device_status_char(&(ms->mirror[m]));
1369 }
1370 buffer[m] = '\0';
1371
1372 DMEMIT("%llu/%llu 1 %s ",
1373 (unsigned long long)log->type->get_sync_count(log),
1374 (unsigned long long)ms->nr_regions, buffer);
1375
1376 sz += log->type->status(log, type, result+sz, maxlen-sz);
1377
1378 break;
1379
1380 case STATUSTYPE_TABLE:
1381 sz = log->type->status(log, type, result, maxlen);
1382
1383 DMEMIT("%d", ms->nr_mirrors);
1384 for (m = 0; m < ms->nr_mirrors; m++)
1385 DMEMIT(" %s %llu", ms->mirror[m].dev->name,
1386 (unsigned long long)ms->mirror[m].offset);
1387
1388 if (ms->features & DM_RAID1_HANDLE_ERRORS)
1389 DMEMIT(" 1 handle_errors");
1390 }
1391}
1392
1393static int mirror_iterate_devices(struct dm_target *ti,
1394 iterate_devices_callout_fn fn, void *data)
1395{
1396 struct mirror_set *ms = ti->private;
1397 int ret = 0;
1398 unsigned i;
1399
1400 for (i = 0; !ret && i < ms->nr_mirrors; i++)
1401 ret = fn(ti, ms->mirror[i].dev,
1402 ms->mirror[i].offset, ti->len, data);
1403
1404 return ret;
1405}
1406
1407static struct target_type mirror_target = {
1408 .name = "mirror",
1409 .version = {1, 13, 2},
1410 .module = THIS_MODULE,
1411 .ctr = mirror_ctr,
1412 .dtr = mirror_dtr,
1413 .map = mirror_map,
1414 .end_io = mirror_end_io,
1415 .presuspend = mirror_presuspend,
1416 .postsuspend = mirror_postsuspend,
1417 .resume = mirror_resume,
1418 .status = mirror_status,
1419 .iterate_devices = mirror_iterate_devices,
1420};
1421
1422static int __init dm_mirror_init(void)
1423{
1424 int r;
1425
1426 r = dm_register_target(&mirror_target);
1427 if (r < 0) {
1428 DMERR("Failed to register mirror target");
1429 goto bad_target;
1430 }
1431
1432 return 0;
1433
1434bad_target:
1435 return r;
1436}
1437
1438static void __exit dm_mirror_exit(void)
1439{
1440 dm_unregister_target(&mirror_target);
1441}
1442
1443/* Module hooks */
1444module_init(dm_mirror_init);
1445module_exit(dm_mirror_exit);
1446
1447MODULE_DESCRIPTION(DM_NAME " mirror target");
1448MODULE_AUTHOR("Joe Thornber");
1449MODULE_LICENSE("GPL");