2 * Copyright (C) 2003 Sistina Software Limited.
3 * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved.
5 * This file is released under the GPL.
8 #include "dm-bio-record.h"
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>
22 #define DM_MSG_PREFIX "raid1"
24 #define MAX_RECOVERY 1 /* Maximum number of regions recovered in parallel. */
26 #define DM_RAID1_HANDLE_ERRORS 0x01
27 #define errors_handled(p) ((p)->features & DM_RAID1_HANDLE_ERRORS)
29 static DECLARE_WAIT_QUEUE_HEAD(_kmirrord_recovery_stopped);
31 /*-----------------------------------------------------------------
32 * Mirror set structures.
33 *---------------------------------------------------------------*/
42 struct mirror_set *ms;
44 unsigned long error_type;
51 struct list_head list;
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 */
61 struct dm_region_hash *rh;
62 struct dm_kcopyd_client *kcopyd_client;
63 struct dm_io_client *io_client;
64 mempool_t *read_record_pool;
73 atomic_t default_mirror; /* Default mirror */
75 struct workqueue_struct *kmirrord_wq;
76 struct work_struct kmirrord_work;
77 struct timer_list timer;
78 unsigned long timer_pending;
80 struct work_struct trigger_event;
83 struct mirror mirror[0];
86 static void wakeup_mirrord(void *context)
88 struct mirror_set *ms = context;
90 queue_work(ms->kmirrord_wq, &ms->kmirrord_work);
93 static void delayed_wake_fn(unsigned long data)
95 struct mirror_set *ms = (struct mirror_set *) data;
97 clear_bit(0, &ms->timer_pending);
101 static void delayed_wake(struct mirror_set *ms)
103 if (test_and_set_bit(0, &ms->timer_pending))
106 ms->timer.expires = jiffies + HZ / 5;
107 ms->timer.data = (unsigned long) ms;
108 ms->timer.function = delayed_wake_fn;
109 add_timer(&ms->timer);
112 static void wakeup_all_recovery_waiters(void *context)
114 wake_up_all(&_kmirrord_recovery_stopped);
117 static void queue_bio(struct mirror_set *ms, struct bio *bio, int rw)
123 bl = (rw == WRITE) ? &ms->writes : &ms->reads;
124 spin_lock_irqsave(&ms->lock, flags);
125 should_wake = !(bl->head);
126 bio_list_add(bl, bio);
127 spin_unlock_irqrestore(&ms->lock, flags);
133 static void dispatch_bios(void *context, struct bio_list *bio_list)
135 struct mirror_set *ms = context;
138 while ((bio = bio_list_pop(bio_list)))
139 queue_bio(ms, bio, WRITE);
142 #define MIN_READ_RECORDS 20
143 struct dm_raid1_read_record {
145 struct dm_bio_details details;
148 static struct kmem_cache *_dm_raid1_read_record_cache;
151 * Every mirror should look like this one.
153 #define DEFAULT_MIRROR 0
156 * This is yucky. We squirrel the mirror struct away inside
157 * bi_next for read/write buffers. This is safe since the bh
158 * doesn't get submitted to the lower levels of block layer.
160 static struct mirror *bio_get_m(struct bio *bio)
162 return (struct mirror *) bio->bi_next;
165 static void bio_set_m(struct bio *bio, struct mirror *m)
167 bio->bi_next = (struct bio *) m;
170 static struct mirror *get_default_mirror(struct mirror_set *ms)
172 return &ms->mirror[atomic_read(&ms->default_mirror)];
175 static void set_default_mirror(struct mirror *m)
177 struct mirror_set *ms = m->ms;
178 struct mirror *m0 = &(ms->mirror[0]);
180 atomic_set(&ms->default_mirror, m - m0);
183 static struct mirror *get_valid_mirror(struct mirror_set *ms)
187 for (m = ms->mirror; m < ms->mirror + ms->nr_mirrors; m++)
188 if (!atomic_read(&m->error_count))
195 * @m: mirror device to fail
196 * @error_type: one of the enum's, DM_RAID1_*_ERROR
198 * If errors are being handled, record the type of
199 * error encountered for this device. If this type
200 * of error has already been recorded, we can return;
201 * otherwise, we must signal userspace by triggering
202 * an event. Additionally, if the device is the
203 * primary device, we must choose a new primary, but
204 * only if the mirror is in-sync.
206 * This function must not block.
208 static void fail_mirror(struct mirror *m, enum dm_raid1_error error_type)
210 struct mirror_set *ms = m->ms;
216 * error_count is used for nothing more than a
217 * simple way to tell if a device has encountered
220 atomic_inc(&m->error_count);
222 if (test_and_set_bit(error_type, &m->error_type))
225 if (!errors_handled(ms))
228 if (m != get_default_mirror(ms))
233 * Better to issue requests to same failing device
234 * than to risk returning corrupt data.
236 DMERR("Primary mirror (%s) failed while out-of-sync: "
237 "Reads may fail.", m->dev->name);
241 new = get_valid_mirror(ms);
243 set_default_mirror(new);
245 DMWARN("All sides of mirror have failed.");
248 schedule_work(&ms->trigger_event);
251 static int mirror_flush(struct dm_target *ti)
253 struct mirror_set *ms = ti->private;
254 unsigned long error_bits;
257 struct dm_io_region io[ms->nr_mirrors];
259 struct dm_io_request io_req = {
260 .bi_rw = WRITE_FLUSH,
261 .mem.type = DM_IO_KMEM,
262 .mem.ptr.addr = NULL,
263 .client = ms->io_client,
266 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++) {
267 io[i].bdev = m->dev->bdev;
273 dm_io(&io_req, ms->nr_mirrors, io, &error_bits);
274 if (unlikely(error_bits != 0)) {
275 for (i = 0; i < ms->nr_mirrors; i++)
276 if (test_bit(i, &error_bits))
277 fail_mirror(ms->mirror + i,
278 DM_RAID1_FLUSH_ERROR);
285 /*-----------------------------------------------------------------
288 * When a mirror is first activated we may find that some regions
289 * are in the no-sync state. We have to recover these by
290 * recopying from the default mirror to all the others.
291 *---------------------------------------------------------------*/
292 static void recovery_complete(int read_err, unsigned long write_err,
295 struct dm_region *reg = context;
296 struct mirror_set *ms = dm_rh_region_context(reg);
300 /* Read error means the failure of default mirror. */
301 DMERR_LIMIT("Unable to read primary mirror during recovery");
302 fail_mirror(get_default_mirror(ms), DM_RAID1_SYNC_ERROR);
306 DMERR_LIMIT("Write error during recovery (error = 0x%lx)",
309 * Bits correspond to devices (excluding default mirror).
310 * The default mirror cannot change during recovery.
312 for (m = 0; m < ms->nr_mirrors; m++) {
313 if (&ms->mirror[m] == get_default_mirror(ms))
315 if (test_bit(bit, &write_err))
316 fail_mirror(ms->mirror + m,
317 DM_RAID1_SYNC_ERROR);
322 dm_rh_recovery_end(reg, !(read_err || write_err));
325 static int recover(struct mirror_set *ms, struct dm_region *reg)
329 struct dm_io_region from, to[DM_KCOPYD_MAX_REGIONS], *dest;
331 unsigned long flags = 0;
332 region_t key = dm_rh_get_region_key(reg);
333 sector_t region_size = dm_rh_get_region_size(ms->rh);
335 /* fill in the source */
336 m = get_default_mirror(ms);
337 from.bdev = m->dev->bdev;
338 from.sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
339 if (key == (ms->nr_regions - 1)) {
341 * The final region may be smaller than
344 from.count = ms->ti->len & (region_size - 1);
346 from.count = region_size;
348 from.count = region_size;
350 /* fill in the destinations */
351 for (i = 0, dest = to; i < ms->nr_mirrors; i++) {
352 if (&ms->mirror[i] == get_default_mirror(ms))
356 dest->bdev = m->dev->bdev;
357 dest->sector = m->offset + dm_rh_region_to_sector(ms->rh, key);
358 dest->count = from.count;
363 if (!errors_handled(ms))
364 set_bit(DM_KCOPYD_IGNORE_ERROR, &flags);
366 r = dm_kcopyd_copy(ms->kcopyd_client, &from, ms->nr_mirrors - 1, to,
367 flags, recovery_complete, reg);
372 static void do_recovery(struct mirror_set *ms)
374 struct dm_region *reg;
375 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
379 * Start quiescing some regions.
381 dm_rh_recovery_prepare(ms->rh);
384 * Copy any already quiesced regions.
386 while ((reg = dm_rh_recovery_start(ms->rh))) {
387 r = recover(ms, reg);
389 dm_rh_recovery_end(reg, 0);
393 * Update the in sync flag.
396 (log->type->get_sync_count(log) == ms->nr_regions)) {
397 /* the sync is complete */
398 dm_table_event(ms->ti->table);
403 /*-----------------------------------------------------------------
405 *---------------------------------------------------------------*/
406 static struct mirror *choose_mirror(struct mirror_set *ms, sector_t sector)
408 struct mirror *m = get_default_mirror(ms);
411 if (likely(!atomic_read(&m->error_count)))
414 if (m-- == ms->mirror)
416 } while (m != get_default_mirror(ms));
421 static int default_ok(struct mirror *m)
423 struct mirror *default_mirror = get_default_mirror(m->ms);
425 return !atomic_read(&default_mirror->error_count);
428 static int mirror_available(struct mirror_set *ms, struct bio *bio)
430 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
431 region_t region = dm_rh_bio_to_region(ms->rh, bio);
433 if (log->type->in_sync(log, region, 0))
434 return choose_mirror(ms, bio->bi_sector) ? 1 : 0;
440 * remap a buffer to a particular mirror.
442 static sector_t map_sector(struct mirror *m, struct bio *bio)
444 if (unlikely(!bio->bi_size))
446 return m->offset + dm_target_offset(m->ms->ti, bio->bi_sector);
449 static void map_bio(struct mirror *m, struct bio *bio)
451 bio->bi_bdev = m->dev->bdev;
452 bio->bi_sector = map_sector(m, bio);
455 static void map_region(struct dm_io_region *io, struct mirror *m,
458 io->bdev = m->dev->bdev;
459 io->sector = map_sector(m, bio);
460 io->count = bio->bi_size >> 9;
463 static void hold_bio(struct mirror_set *ms, struct bio *bio)
466 * Lock is required to avoid race condition during suspend
469 spin_lock_irq(&ms->lock);
471 if (atomic_read(&ms->suspend)) {
472 spin_unlock_irq(&ms->lock);
475 * If device is suspended, complete the bio.
477 if (dm_noflush_suspending(ms->ti))
478 bio_endio(bio, DM_ENDIO_REQUEUE);
480 bio_endio(bio, -EIO);
485 * Hold bio until the suspend is complete.
487 bio_list_add(&ms->holds, bio);
488 spin_unlock_irq(&ms->lock);
491 /*-----------------------------------------------------------------
493 *---------------------------------------------------------------*/
494 static void read_callback(unsigned long error, void *context)
496 struct bio *bio = context;
500 bio_set_m(bio, NULL);
502 if (likely(!error)) {
507 fail_mirror(m, DM_RAID1_READ_ERROR);
509 if (likely(default_ok(m)) || mirror_available(m->ms, bio)) {
510 DMWARN_LIMIT("Read failure on mirror device %s. "
511 "Trying alternative device.",
513 queue_bio(m->ms, bio, bio_rw(bio));
517 DMERR_LIMIT("Read failure on mirror device %s. Failing I/O.",
519 bio_endio(bio, -EIO);
522 /* Asynchronous read. */
523 static void read_async_bio(struct mirror *m, struct bio *bio)
525 struct dm_io_region io;
526 struct dm_io_request io_req = {
528 .mem.type = DM_IO_BVEC,
529 .mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx,
530 .notify.fn = read_callback,
531 .notify.context = bio,
532 .client = m->ms->io_client,
535 map_region(&io, m, bio);
537 BUG_ON(dm_io(&io_req, 1, &io, NULL));
540 static inline int region_in_sync(struct mirror_set *ms, region_t region,
543 int state = dm_rh_get_state(ms->rh, region, may_block);
544 return state == DM_RH_CLEAN || state == DM_RH_DIRTY;
547 static void do_reads(struct mirror_set *ms, struct bio_list *reads)
553 while ((bio = bio_list_pop(reads))) {
554 region = dm_rh_bio_to_region(ms->rh, bio);
555 m = get_default_mirror(ms);
558 * We can only read balance if the region is in sync.
560 if (likely(region_in_sync(ms, region, 1)))
561 m = choose_mirror(ms, bio->bi_sector);
562 else if (m && atomic_read(&m->error_count))
566 read_async_bio(m, bio);
568 bio_endio(bio, -EIO);
572 /*-----------------------------------------------------------------
575 * We do different things with the write io depending on the
576 * state of the region that it's in:
578 * SYNC: increment pending, use kcopyd to write to *all* mirrors
579 * RECOVERING: delay the io until recovery completes
580 * NOSYNC: increment pending, just write to the default mirror
581 *---------------------------------------------------------------*/
584 static void write_callback(unsigned long error, void *context)
587 struct bio *bio = (struct bio *) context;
588 struct mirror_set *ms;
592 ms = bio_get_m(bio)->ms;
593 bio_set_m(bio, NULL);
596 * NOTE: We don't decrement the pending count here,
597 * instead it is done by the targets endio function.
598 * This way we handle both writes to SYNC and NOSYNC
599 * regions with the same code.
601 if (likely(!error)) {
607 * If the bio is discard, return an error, but do not
610 if (bio->bi_rw & REQ_DISCARD) {
611 bio_endio(bio, -EOPNOTSUPP);
615 for (i = 0; i < ms->nr_mirrors; i++)
616 if (test_bit(i, &error))
617 fail_mirror(ms->mirror + i, DM_RAID1_WRITE_ERROR);
620 * Need to raise event. Since raising
621 * events can block, we need to do it in
624 spin_lock_irqsave(&ms->lock, flags);
625 if (!ms->failures.head)
627 bio_list_add(&ms->failures, bio);
628 spin_unlock_irqrestore(&ms->lock, flags);
633 static void do_write(struct mirror_set *ms, struct bio *bio)
636 struct dm_io_region io[ms->nr_mirrors], *dest = io;
638 struct dm_io_request io_req = {
639 .bi_rw = WRITE | (bio->bi_rw & WRITE_FLUSH_FUA),
640 .mem.type = DM_IO_BVEC,
641 .mem.ptr.bvec = bio->bi_io_vec + bio->bi_idx,
642 .notify.fn = write_callback,
643 .notify.context = bio,
644 .client = ms->io_client,
647 if (bio->bi_rw & REQ_DISCARD) {
648 io_req.bi_rw |= REQ_DISCARD;
649 io_req.mem.type = DM_IO_KMEM;
650 io_req.mem.ptr.addr = NULL;
653 for (i = 0, m = ms->mirror; i < ms->nr_mirrors; i++, m++)
654 map_region(dest++, m, bio);
657 * Use default mirror because we only need it to retrieve the reference
658 * to the mirror set in write_callback().
660 bio_set_m(bio, get_default_mirror(ms));
662 BUG_ON(dm_io(&io_req, ms->nr_mirrors, io, NULL));
665 static void do_writes(struct mirror_set *ms, struct bio_list *writes)
669 struct bio_list sync, nosync, recover, *this_list = NULL;
670 struct bio_list requeue;
671 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
678 * Classify each write.
680 bio_list_init(&sync);
681 bio_list_init(&nosync);
682 bio_list_init(&recover);
683 bio_list_init(&requeue);
685 while ((bio = bio_list_pop(writes))) {
686 if ((bio->bi_rw & REQ_FLUSH) ||
687 (bio->bi_rw & REQ_DISCARD)) {
688 bio_list_add(&sync, bio);
692 region = dm_rh_bio_to_region(ms->rh, bio);
694 if (log->type->is_remote_recovering &&
695 log->type->is_remote_recovering(log, region)) {
696 bio_list_add(&requeue, bio);
700 state = dm_rh_get_state(ms->rh, region, 1);
711 case DM_RH_RECOVERING:
712 this_list = &recover;
716 bio_list_add(this_list, bio);
720 * Add bios that are delayed due to remote recovery
721 * back on to the write queue
723 if (unlikely(requeue.head)) {
724 spin_lock_irq(&ms->lock);
725 bio_list_merge(&ms->writes, &requeue);
726 spin_unlock_irq(&ms->lock);
731 * Increment the pending counts for any regions that will
732 * be written to (writes to recover regions are going to
735 dm_rh_inc_pending(ms->rh, &sync);
736 dm_rh_inc_pending(ms->rh, &nosync);
739 * If the flush fails on a previous call and succeeds here,
740 * we must not reset the log_failure variable. We need
741 * userspace interaction to do that.
743 ms->log_failure = dm_rh_flush(ms->rh) ? 1 : ms->log_failure;
748 if (unlikely(ms->log_failure) && errors_handled(ms)) {
749 spin_lock_irq(&ms->lock);
750 bio_list_merge(&ms->failures, &sync);
751 spin_unlock_irq(&ms->lock);
754 while ((bio = bio_list_pop(&sync)))
757 while ((bio = bio_list_pop(&recover)))
758 dm_rh_delay(ms->rh, bio);
760 while ((bio = bio_list_pop(&nosync))) {
761 if (unlikely(ms->leg_failure) && errors_handled(ms)) {
762 spin_lock_irq(&ms->lock);
763 bio_list_add(&ms->failures, bio);
764 spin_unlock_irq(&ms->lock);
767 map_bio(get_default_mirror(ms), bio);
768 generic_make_request(bio);
773 static void do_failures(struct mirror_set *ms, struct bio_list *failures)
777 if (likely(!failures->head))
781 * If the log has failed, unattempted writes are being
782 * put on the holds list. We can't issue those writes
783 * until a log has been marked, so we must store them.
785 * If a 'noflush' suspend is in progress, we can requeue
786 * the I/O's to the core. This give userspace a chance
787 * to reconfigure the mirror, at which point the core
788 * will reissue the writes. If the 'noflush' flag is
789 * not set, we have no choice but to return errors.
791 * Some writes on the failures list may have been
792 * submitted before the log failure and represent a
793 * failure to write to one of the devices. It is ok
794 * for us to treat them the same and requeue them
797 while ((bio = bio_list_pop(failures))) {
798 if (!ms->log_failure) {
800 dm_rh_mark_nosync(ms->rh, bio);
804 * If all the legs are dead, fail the I/O.
805 * If we have been told to handle errors, hold the bio
806 * and wait for userspace to deal with the problem.
807 * Otherwise pretend that the I/O succeeded. (This would
808 * be wrong if the failed leg returned after reboot and
809 * got replicated back to the good legs.)
811 if (!get_valid_mirror(ms))
812 bio_endio(bio, -EIO);
813 else if (errors_handled(ms))
820 static void trigger_event(struct work_struct *work)
822 struct mirror_set *ms =
823 container_of(work, struct mirror_set, trigger_event);
825 dm_table_event(ms->ti->table);
828 /*-----------------------------------------------------------------
830 *---------------------------------------------------------------*/
831 static void do_mirror(struct work_struct *work)
833 struct mirror_set *ms = container_of(work, struct mirror_set,
835 struct bio_list reads, writes, failures;
838 spin_lock_irqsave(&ms->lock, flags);
841 failures = ms->failures;
842 bio_list_init(&ms->reads);
843 bio_list_init(&ms->writes);
844 bio_list_init(&ms->failures);
845 spin_unlock_irqrestore(&ms->lock, flags);
847 dm_rh_update_states(ms->rh, errors_handled(ms));
849 do_reads(ms, &reads);
850 do_writes(ms, &writes);
851 do_failures(ms, &failures);
854 /*-----------------------------------------------------------------
856 *---------------------------------------------------------------*/
857 static struct mirror_set *alloc_context(unsigned int nr_mirrors,
858 uint32_t region_size,
859 struct dm_target *ti,
860 struct dm_dirty_log *dl)
863 struct mirror_set *ms = NULL;
865 len = sizeof(*ms) + (sizeof(ms->mirror[0]) * nr_mirrors);
867 ms = kzalloc(len, GFP_KERNEL);
869 ti->error = "Cannot allocate mirror context";
873 spin_lock_init(&ms->lock);
874 bio_list_init(&ms->reads);
875 bio_list_init(&ms->writes);
876 bio_list_init(&ms->failures);
877 bio_list_init(&ms->holds);
880 ms->nr_mirrors = nr_mirrors;
881 ms->nr_regions = dm_sector_div_up(ti->len, region_size);
885 atomic_set(&ms->suspend, 0);
886 atomic_set(&ms->default_mirror, DEFAULT_MIRROR);
888 ms->read_record_pool = mempool_create_slab_pool(MIN_READ_RECORDS,
889 _dm_raid1_read_record_cache);
891 if (!ms->read_record_pool) {
892 ti->error = "Error creating mirror read_record_pool";
897 ms->io_client = dm_io_client_create();
898 if (IS_ERR(ms->io_client)) {
899 ti->error = "Error creating dm_io client";
900 mempool_destroy(ms->read_record_pool);
905 ms->rh = dm_region_hash_create(ms, dispatch_bios, wakeup_mirrord,
906 wakeup_all_recovery_waiters,
907 ms->ti->begin, MAX_RECOVERY,
908 dl, region_size, ms->nr_regions);
909 if (IS_ERR(ms->rh)) {
910 ti->error = "Error creating dirty region hash";
911 dm_io_client_destroy(ms->io_client);
912 mempool_destroy(ms->read_record_pool);
920 static void free_context(struct mirror_set *ms, struct dm_target *ti,
924 dm_put_device(ti, ms->mirror[m].dev);
926 dm_io_client_destroy(ms->io_client);
927 dm_region_hash_destroy(ms->rh);
928 mempool_destroy(ms->read_record_pool);
932 static int get_mirror(struct mirror_set *ms, struct dm_target *ti,
933 unsigned int mirror, char **argv)
935 unsigned long long offset;
937 if (sscanf(argv[1], "%llu", &offset) != 1) {
938 ti->error = "Invalid offset";
942 if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table),
943 &ms->mirror[mirror].dev)) {
944 ti->error = "Device lookup failure";
948 ms->mirror[mirror].ms = ms;
949 atomic_set(&(ms->mirror[mirror].error_count), 0);
950 ms->mirror[mirror].error_type = 0;
951 ms->mirror[mirror].offset = offset;
957 * Create dirty log: log_type #log_params <log_params>
959 static struct dm_dirty_log *create_dirty_log(struct dm_target *ti,
960 unsigned argc, char **argv,
963 unsigned param_count;
964 struct dm_dirty_log *dl;
967 ti->error = "Insufficient mirror log arguments";
971 if (sscanf(argv[1], "%u", ¶m_count) != 1) {
972 ti->error = "Invalid mirror log argument count";
976 *args_used = 2 + param_count;
978 if (argc < *args_used) {
979 ti->error = "Insufficient mirror log arguments";
983 dl = dm_dirty_log_create(argv[0], ti, mirror_flush, param_count,
986 ti->error = "Error creating mirror dirty log";
993 static int parse_features(struct mirror_set *ms, unsigned argc, char **argv,
996 unsigned num_features;
997 struct dm_target *ti = ms->ti;
1004 if (sscanf(argv[0], "%u", &num_features) != 1) {
1005 ti->error = "Invalid number of features";
1013 if (num_features > argc) {
1014 ti->error = "Not enough arguments to support feature count";
1018 if (!strcmp("handle_errors", argv[0]))
1019 ms->features |= DM_RAID1_HANDLE_ERRORS;
1021 ti->error = "Unrecognised feature requested";
1031 * Construct a mirror mapping:
1033 * log_type #log_params <log_params>
1034 * #mirrors [mirror_path offset]{2,}
1035 * [#features <features>]
1037 * log_type is "core" or "disk"
1038 * #log_params is between 1 and 3
1040 * If present, features must be "handle_errors".
1042 static int mirror_ctr(struct dm_target *ti, unsigned int argc, char **argv)
1045 unsigned int nr_mirrors, m, args_used;
1046 struct mirror_set *ms;
1047 struct dm_dirty_log *dl;
1049 dl = create_dirty_log(ti, argc, argv, &args_used);
1056 if (!argc || sscanf(argv[0], "%u", &nr_mirrors) != 1 ||
1057 nr_mirrors < 2 || nr_mirrors > DM_KCOPYD_MAX_REGIONS + 1) {
1058 ti->error = "Invalid number of mirrors";
1059 dm_dirty_log_destroy(dl);
1065 if (argc < nr_mirrors * 2) {
1066 ti->error = "Too few mirror arguments";
1067 dm_dirty_log_destroy(dl);
1071 ms = alloc_context(nr_mirrors, dl->type->get_region_size(dl), ti, dl);
1073 dm_dirty_log_destroy(dl);
1077 /* Get the mirror parameter sets */
1078 for (m = 0; m < nr_mirrors; m++) {
1079 r = get_mirror(ms, ti, m, argv);
1081 free_context(ms, ti, m);
1089 ti->split_io = dm_rh_get_region_size(ms->rh);
1090 ti->num_flush_requests = 1;
1091 ti->num_discard_requests = 1;
1092 ti->discard_zeroes_data_unsupported = 1;
1094 ms->kmirrord_wq = alloc_workqueue("kmirrord",
1095 WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
1096 if (!ms->kmirrord_wq) {
1097 DMERR("couldn't start kmirrord");
1099 goto err_free_context;
1101 INIT_WORK(&ms->kmirrord_work, do_mirror);
1102 init_timer(&ms->timer);
1103 ms->timer_pending = 0;
1104 INIT_WORK(&ms->trigger_event, trigger_event);
1106 r = parse_features(ms, argc, argv, &args_used);
1108 goto err_destroy_wq;
1114 * Any read-balancing addition depends on the
1115 * DM_RAID1_HANDLE_ERRORS flag being present.
1116 * This is because the decision to balance depends
1117 * on the sync state of a region. If the above
1118 * flag is not present, we ignore errors; and
1119 * the sync state may be inaccurate.
1123 ti->error = "Too many mirror arguments";
1125 goto err_destroy_wq;
1128 ms->kcopyd_client = dm_kcopyd_client_create();
1129 if (IS_ERR(ms->kcopyd_client)) {
1130 r = PTR_ERR(ms->kcopyd_client);
1131 goto err_destroy_wq;
1138 destroy_workqueue(ms->kmirrord_wq);
1140 free_context(ms, ti, ms->nr_mirrors);
1144 static void mirror_dtr(struct dm_target *ti)
1146 struct mirror_set *ms = (struct mirror_set *) ti->private;
1148 del_timer_sync(&ms->timer);
1149 flush_workqueue(ms->kmirrord_wq);
1150 flush_work_sync(&ms->trigger_event);
1151 dm_kcopyd_client_destroy(ms->kcopyd_client);
1152 destroy_workqueue(ms->kmirrord_wq);
1153 free_context(ms, ti, ms->nr_mirrors);
1157 * Mirror mapping function
1159 static int mirror_map(struct dm_target *ti, struct bio *bio,
1160 union map_info *map_context)
1162 int r, rw = bio_rw(bio);
1164 struct mirror_set *ms = ti->private;
1165 struct dm_raid1_read_record *read_record = NULL;
1166 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1169 /* Save region for mirror_end_io() handler */
1170 map_context->ll = dm_rh_bio_to_region(ms->rh, bio);
1171 queue_bio(ms, bio, rw);
1172 return DM_MAPIO_SUBMITTED;
1175 r = log->type->in_sync(log, dm_rh_bio_to_region(ms->rh, bio), 0);
1176 if (r < 0 && r != -EWOULDBLOCK)
1180 * If region is not in-sync queue the bio.
1182 if (!r || (r == -EWOULDBLOCK)) {
1184 return -EWOULDBLOCK;
1186 queue_bio(ms, bio, rw);
1187 return DM_MAPIO_SUBMITTED;
1191 * The region is in-sync and we can perform reads directly.
1192 * Store enough information so we can retry if it fails.
1194 m = choose_mirror(ms, bio->bi_sector);
1198 read_record = mempool_alloc(ms->read_record_pool, GFP_NOIO);
1199 if (likely(read_record)) {
1200 dm_bio_record(&read_record->details, bio);
1201 map_context->ptr = read_record;
1207 return DM_MAPIO_REMAPPED;
1210 static int mirror_end_io(struct dm_target *ti, struct bio *bio,
1211 int error, union map_info *map_context)
1213 int rw = bio_rw(bio);
1214 struct mirror_set *ms = (struct mirror_set *) ti->private;
1215 struct mirror *m = NULL;
1216 struct dm_bio_details *bd = NULL;
1217 struct dm_raid1_read_record *read_record = map_context->ptr;
1220 * We need to dec pending if this was a write.
1223 if (!(bio->bi_rw & (REQ_FLUSH | REQ_DISCARD)))
1224 dm_rh_dec(ms->rh, map_context->ll);
1228 if (error == -EOPNOTSUPP)
1231 if ((error == -EWOULDBLOCK) && (bio->bi_rw & REQ_RAHEAD))
1234 if (unlikely(error)) {
1237 * There wasn't enough memory to record necessary
1238 * information for a retry or there was no other
1241 DMERR_LIMIT("Mirror read failed.");
1247 DMERR("Mirror read failed from %s. Trying alternative device.",
1250 fail_mirror(m, DM_RAID1_READ_ERROR);
1253 * A failed read is requeued for another attempt using an intact
1256 if (default_ok(m) || mirror_available(ms, bio)) {
1257 bd = &read_record->details;
1259 dm_bio_restore(bd, bio);
1260 mempool_free(read_record, ms->read_record_pool);
1261 map_context->ptr = NULL;
1262 queue_bio(ms, bio, rw);
1265 DMERR("All replicated volumes dead, failing I/O");
1270 mempool_free(read_record, ms->read_record_pool);
1271 map_context->ptr = NULL;
1277 static void mirror_presuspend(struct dm_target *ti)
1279 struct mirror_set *ms = (struct mirror_set *) ti->private;
1280 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1282 struct bio_list holds;
1285 atomic_set(&ms->suspend, 1);
1288 * Process bios in the hold list to start recovery waiting
1289 * for bios in the hold list. After the process, no bio has
1290 * a chance to be added in the hold list because ms->suspend
1293 spin_lock_irq(&ms->lock);
1295 bio_list_init(&ms->holds);
1296 spin_unlock_irq(&ms->lock);
1298 while ((bio = bio_list_pop(&holds)))
1302 * We must finish up all the work that we've
1303 * generated (i.e. recovery work).
1305 dm_rh_stop_recovery(ms->rh);
1307 wait_event(_kmirrord_recovery_stopped,
1308 !dm_rh_recovery_in_flight(ms->rh));
1310 if (log->type->presuspend && log->type->presuspend(log))
1311 /* FIXME: need better error handling */
1312 DMWARN("log presuspend failed");
1315 * Now that recovery is complete/stopped and the
1316 * delayed bios are queued, we need to wait for
1317 * the worker thread to complete. This way,
1318 * we know that all of our I/O has been pushed.
1320 flush_workqueue(ms->kmirrord_wq);
1323 static void mirror_postsuspend(struct dm_target *ti)
1325 struct mirror_set *ms = ti->private;
1326 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1328 if (log->type->postsuspend && log->type->postsuspend(log))
1329 /* FIXME: need better error handling */
1330 DMWARN("log postsuspend failed");
1333 static void mirror_resume(struct dm_target *ti)
1335 struct mirror_set *ms = ti->private;
1336 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1338 atomic_set(&ms->suspend, 0);
1339 if (log->type->resume && log->type->resume(log))
1340 /* FIXME: need better error handling */
1341 DMWARN("log resume failed");
1342 dm_rh_start_recovery(ms->rh);
1346 * device_status_char
1347 * @m: mirror device/leg we want the status of
1349 * We return one character representing the most severe error
1350 * we have encountered.
1351 * A => Alive - No failures
1352 * D => Dead - A write failure occurred leaving mirror out-of-sync
1353 * S => Sync - A sychronization failure occurred, mirror out-of-sync
1354 * R => Read - A read failure occurred, mirror data unaffected
1358 static char device_status_char(struct mirror *m)
1360 if (!atomic_read(&(m->error_count)))
1363 return (test_bit(DM_RAID1_FLUSH_ERROR, &(m->error_type))) ? 'F' :
1364 (test_bit(DM_RAID1_WRITE_ERROR, &(m->error_type))) ? 'D' :
1365 (test_bit(DM_RAID1_SYNC_ERROR, &(m->error_type))) ? 'S' :
1366 (test_bit(DM_RAID1_READ_ERROR, &(m->error_type))) ? 'R' : 'U';
1370 static void mirror_status(struct dm_target *ti, status_type_t type,
1371 char *result, unsigned maxlen)
1373 unsigned int m, sz = 0;
1374 struct mirror_set *ms = (struct mirror_set *) ti->private;
1375 struct dm_dirty_log *log = dm_rh_dirty_log(ms->rh);
1376 char buffer[ms->nr_mirrors + 1];
1379 case STATUSTYPE_INFO:
1380 DMEMIT("%d ", ms->nr_mirrors);
1381 for (m = 0; m < ms->nr_mirrors; m++) {
1382 DMEMIT("%s ", ms->mirror[m].dev->name);
1383 buffer[m] = device_status_char(&(ms->mirror[m]));
1387 DMEMIT("%llu/%llu 1 %s ",
1388 (unsigned long long)log->type->get_sync_count(log),
1389 (unsigned long long)ms->nr_regions, buffer);
1391 sz += log->type->status(log, type, result+sz, maxlen-sz);
1395 case STATUSTYPE_TABLE:
1396 sz = log->type->status(log, type, result, maxlen);
1398 DMEMIT("%d", ms->nr_mirrors);
1399 for (m = 0; m < ms->nr_mirrors; m++)
1400 DMEMIT(" %s %llu", ms->mirror[m].dev->name,
1401 (unsigned long long)ms->mirror[m].offset);
1403 if (ms->features & DM_RAID1_HANDLE_ERRORS)
1404 DMEMIT(" 1 handle_errors");
1408 static int mirror_iterate_devices(struct dm_target *ti,
1409 iterate_devices_callout_fn fn, void *data)
1411 struct mirror_set *ms = ti->private;
1415 for (i = 0; !ret && i < ms->nr_mirrors; i++)
1416 ret = fn(ti, ms->mirror[i].dev,
1417 ms->mirror[i].offset, ti->len, data);
1422 static struct target_type mirror_target = {
1424 .version = {1, 12, 2},
1425 .module = THIS_MODULE,
1429 .end_io = mirror_end_io,
1430 .presuspend = mirror_presuspend,
1431 .postsuspend = mirror_postsuspend,
1432 .resume = mirror_resume,
1433 .status = mirror_status,
1434 .iterate_devices = mirror_iterate_devices,
1437 static int __init dm_mirror_init(void)
1441 _dm_raid1_read_record_cache = KMEM_CACHE(dm_raid1_read_record, 0);
1442 if (!_dm_raid1_read_record_cache) {
1443 DMERR("Can't allocate dm_raid1_read_record cache");
1448 r = dm_register_target(&mirror_target);
1450 DMERR("Failed to register mirror target");
1457 kmem_cache_destroy(_dm_raid1_read_record_cache);
1462 static void __exit dm_mirror_exit(void)
1464 dm_unregister_target(&mirror_target);
1465 kmem_cache_destroy(_dm_raid1_read_record_cache);
1469 module_init(dm_mirror_init);
1470 module_exit(dm_mirror_exit);
1472 MODULE_DESCRIPTION(DM_NAME " mirror target");
1473 MODULE_AUTHOR("Joe Thornber");
1474 MODULE_LICENSE("GPL");