diff options
Diffstat (limited to 'drivers/md/raid5.c')
| -rw-r--r-- | drivers/md/raid5.c | 203 |
1 files changed, 61 insertions, 142 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 26e1e8a5e941..8497880135ee 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -36,7 +36,6 @@ */ #include <linux/blkdev.h> -#include <linux/delay.h> #include <linux/kthread.h> #include <linux/raid/pq.h> #include <linux/async_tx.h> @@ -694,12 +693,12 @@ int raid5_calc_degraded(struct r5conf *conf) int degraded, degraded2; int i; - rcu_read_lock(); degraded = 0; for (i = 0; i < conf->previous_raid_disks; i++) { - struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev); + struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev); + if (rdev && test_bit(Faulty, &rdev->flags)) - rdev = rcu_dereference(conf->disks[i].replacement); + rdev = READ_ONCE(conf->disks[i].replacement); if (!rdev || test_bit(Faulty, &rdev->flags)) degraded++; else if (test_bit(In_sync, &rdev->flags)) @@ -717,15 +716,14 @@ int raid5_calc_degraded(struct r5conf *conf) if (conf->raid_disks >= conf->previous_raid_disks) degraded++; } - rcu_read_unlock(); if (conf->raid_disks == conf->previous_raid_disks) return degraded; - rcu_read_lock(); degraded2 = 0; for (i = 0; i < conf->raid_disks; i++) { - struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev); + struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev); + if (rdev && test_bit(Faulty, &rdev->flags)) - rdev = rcu_dereference(conf->disks[i].replacement); + rdev = READ_ONCE(conf->disks[i].replacement); if (!rdev || test_bit(Faulty, &rdev->flags)) degraded2++; else if (test_bit(In_sync, &rdev->flags)) @@ -739,7 +737,6 @@ int raid5_calc_degraded(struct r5conf *conf) if (conf->raid_disks <= conf->previous_raid_disks) degraded2++; } - rcu_read_unlock(); if (degraded2 > degraded) return degraded2; return degraded; @@ -1184,14 +1181,8 @@ again: bi = &dev->req; rbi = &dev->rreq; /* For writing to replacement */ - rcu_read_lock(); - rrdev = rcu_dereference(conf->disks[i].replacement); - smp_mb(); /* Ensure that if rrdev is NULL, rdev won't be */ - rdev = rcu_dereference(conf->disks[i].rdev); - if (!rdev) { - rdev = rrdev; - rrdev = NULL; - } + rdev = conf->disks[i].rdev; + rrdev = conf->disks[i].replacement; if (op_is_write(op)) { if (replace_only) rdev = NULL; @@ -1212,7 +1203,6 @@ again: rrdev = NULL; if (rrdev) atomic_inc(&rrdev->nr_pending); - rcu_read_unlock(); /* We have already checked bad blocks for reads. Now * need to check for writes. We never accept write errors @@ -2731,28 +2721,6 @@ static void shrink_stripes(struct r5conf *conf) conf->slab_cache = NULL; } -/* - * This helper wraps rcu_dereference_protected() and can be used when - * it is known that the nr_pending of the rdev is elevated. - */ -static struct md_rdev *rdev_pend_deref(struct md_rdev __rcu *rdev) -{ - return rcu_dereference_protected(rdev, - atomic_read(&rcu_access_pointer(rdev)->nr_pending)); -} - -/* - * This helper wraps rcu_dereference_protected() and should be used - * when it is known that the mddev_lock() is held. This is safe - * seeing raid5_remove_disk() has the same lock held. - */ -static struct md_rdev *rdev_mdlock_deref(struct mddev *mddev, - struct md_rdev __rcu *rdev) -{ - return rcu_dereference_protected(rdev, - lockdep_is_held(&mddev->reconfig_mutex)); -} - static void raid5_end_read_request(struct bio * bi) { struct stripe_head *sh = bi->bi_private; @@ -2778,9 +2746,9 @@ static void raid5_end_read_request(struct bio * bi) * In that case it moved down to 'rdev'. * rdev is not removed until all requests are finished. */ - rdev = rdev_pend_deref(conf->disks[i].replacement); + rdev = conf->disks[i].replacement; if (!rdev) - rdev = rdev_pend_deref(conf->disks[i].rdev); + rdev = conf->disks[i].rdev; if (use_new_offset(conf, sh)) s = sh->sector + rdev->new_data_offset; @@ -2893,11 +2861,11 @@ static void raid5_end_write_request(struct bio *bi) for (i = 0 ; i < disks; i++) { if (bi == &sh->dev[i].req) { - rdev = rdev_pend_deref(conf->disks[i].rdev); + rdev = conf->disks[i].rdev; break; } if (bi == &sh->dev[i].rreq) { - rdev = rdev_pend_deref(conf->disks[i].replacement); + rdev = conf->disks[i].replacement; if (rdev) replacement = 1; else @@ -2905,7 +2873,7 @@ static void raid5_end_write_request(struct bio *bi) * replaced it. rdev is not removed * until all requests are finished. */ - rdev = rdev_pend_deref(conf->disks[i].rdev); + rdev = conf->disks[i].rdev; break; } } @@ -3667,15 +3635,13 @@ handle_failed_stripe(struct r5conf *conf, struct stripe_head *sh, int bitmap_end = 0; if (test_bit(R5_ReadError, &sh->dev[i].flags)) { - struct md_rdev *rdev; - rcu_read_lock(); - rdev = rcu_dereference(conf->disks[i].rdev); + struct md_rdev *rdev = conf->disks[i].rdev; + if (rdev && test_bit(In_sync, &rdev->flags) && !test_bit(Faulty, &rdev->flags)) atomic_inc(&rdev->nr_pending); else rdev = NULL; - rcu_read_unlock(); if (rdev) { if (!rdev_set_badblocks( rdev, @@ -3793,16 +3759,17 @@ handle_failed_sync(struct r5conf *conf, struct stripe_head *sh, /* During recovery devices cannot be removed, so * locking and refcounting of rdevs is not needed */ - rcu_read_lock(); for (i = 0; i < conf->raid_disks; i++) { - struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev); + struct md_rdev *rdev = conf->disks[i].rdev; + if (rdev && !test_bit(Faulty, &rdev->flags) && !test_bit(In_sync, &rdev->flags) && !rdev_set_badblocks(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), 0)) abort = 1; - rdev = rcu_dereference(conf->disks[i].replacement); + rdev = conf->disks[i].replacement; + if (rdev && !test_bit(Faulty, &rdev->flags) && !test_bit(In_sync, &rdev->flags) @@ -3810,7 +3777,6 @@ handle_failed_sync(struct r5conf *conf, struct stripe_head *sh, RAID5_STRIPE_SECTORS(conf), 0)) abort = 1; } - rcu_read_unlock(); if (abort) conf->recovery_disabled = conf->mddev->recovery_disabled; @@ -3823,15 +3789,13 @@ static int want_replace(struct stripe_head *sh, int disk_idx) struct md_rdev *rdev; int rv = 0; - rcu_read_lock(); - rdev = rcu_dereference(sh->raid_conf->disks[disk_idx].replacement); + rdev = sh->raid_conf->disks[disk_idx].replacement; if (rdev && !test_bit(Faulty, &rdev->flags) && !test_bit(In_sync, &rdev->flags) && (rdev->recovery_offset <= sh->sector || rdev->mddev->recovery_cp <= sh->sector)) rv = 1; - rcu_read_unlock(); return rv; } @@ -4708,7 +4672,6 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s) s->log_failed = r5l_log_disk_error(conf); /* Now to look around and see what can be done */ - rcu_read_lock(); for (i=disks; i--; ) { struct md_rdev *rdev; sector_t first_bad; @@ -4753,7 +4716,7 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s) /* Prefer to use the replacement for reads, but only * if it is recovered enough and has no bad blocks. */ - rdev = rcu_dereference(conf->disks[i].replacement); + rdev = conf->disks[i].replacement; if (rdev && !test_bit(Faulty, &rdev->flags) && rdev->recovery_offset >= sh->sector + RAID5_STRIPE_SECTORS(conf) && !is_badblock(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), @@ -4764,7 +4727,7 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s) set_bit(R5_NeedReplace, &dev->flags); else clear_bit(R5_NeedReplace, &dev->flags); - rdev = rcu_dereference(conf->disks[i].rdev); + rdev = conf->disks[i].rdev; clear_bit(R5_ReadRepl, &dev->flags); } if (rdev && test_bit(Faulty, &rdev->flags)) @@ -4811,8 +4774,8 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s) if (test_bit(R5_WriteError, &dev->flags)) { /* This flag does not apply to '.replacement' * only to .rdev, so make sure to check that*/ - struct md_rdev *rdev2 = rcu_dereference( - conf->disks[i].rdev); + struct md_rdev *rdev2 = conf->disks[i].rdev; + if (rdev2 == rdev) clear_bit(R5_Insync, &dev->flags); if (rdev2 && !test_bit(Faulty, &rdev2->flags)) { @@ -4824,8 +4787,8 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s) if (test_bit(R5_MadeGood, &dev->flags)) { /* This flag does not apply to '.replacement' * only to .rdev, so make sure to check that*/ - struct md_rdev *rdev2 = rcu_dereference( - conf->disks[i].rdev); + struct md_rdev *rdev2 = conf->disks[i].rdev; + if (rdev2 && !test_bit(Faulty, &rdev2->flags)) { s->handle_bad_blocks = 1; atomic_inc(&rdev2->nr_pending); @@ -4833,8 +4796,8 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s) clear_bit(R5_MadeGood, &dev->flags); } if (test_bit(R5_MadeGoodRepl, &dev->flags)) { - struct md_rdev *rdev2 = rcu_dereference( - conf->disks[i].replacement); + struct md_rdev *rdev2 = conf->disks[i].replacement; + if (rdev2 && !test_bit(Faulty, &rdev2->flags)) { s->handle_bad_blocks = 1; atomic_inc(&rdev2->nr_pending); @@ -4855,8 +4818,7 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s) if (rdev && !test_bit(Faulty, &rdev->flags)) do_recovery = 1; else if (!rdev) { - rdev = rcu_dereference( - conf->disks[i].replacement); + rdev = conf->disks[i].replacement; if (rdev && !test_bit(Faulty, &rdev->flags)) do_recovery = 1; } @@ -4883,7 +4845,6 @@ static void analyse_stripe(struct stripe_head *sh, struct stripe_head_state *s) else s->replacing = 1; } - rcu_read_unlock(); } /* @@ -5340,23 +5301,23 @@ finish: struct r5dev *dev = &sh->dev[i]; if (test_and_clear_bit(R5_WriteError, &dev->flags)) { /* We own a safe reference to the rdev */ - rdev = rdev_pend_deref(conf->disks[i].rdev); + rdev = conf->disks[i].rdev; if (!rdev_set_badblocks(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), 0)) md_error(conf->mddev, rdev); rdev_dec_pending(rdev, conf->mddev); } if (test_and_clear_bit(R5_MadeGood, &dev->flags)) { - rdev = rdev_pend_deref(conf->disks[i].rdev); + rdev = conf->disks[i].rdev; rdev_clear_badblocks(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), 0); rdev_dec_pending(rdev, conf->mddev); } if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) { - rdev = rdev_pend_deref(conf->disks[i].replacement); + rdev = conf->disks[i].replacement; if (!rdev) /* rdev have been moved down */ - rdev = rdev_pend_deref(conf->disks[i].rdev); + rdev = conf->disks[i].rdev; rdev_clear_badblocks(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), 0); rdev_dec_pending(rdev, conf->mddev); @@ -5515,24 +5476,22 @@ static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio) &dd_idx, NULL); end_sector = sector + bio_sectors(raid_bio); - rcu_read_lock(); if (r5c_big_stripe_cached(conf, sector)) - goto out_rcu_unlock; + return 0; - rdev = rcu_dereference(conf->disks[dd_idx].replacement); + rdev = conf->disks[dd_idx].replacement; if (!rdev || test_bit(Faulty, &rdev->flags) || rdev->recovery_offset < end_sector) { - rdev = rcu_dereference(conf->disks[dd_idx].rdev); + rdev = conf->disks[dd_idx].rdev; if (!rdev) - goto out_rcu_unlock; + return 0; if (test_bit(Faulty, &rdev->flags) || !(test_bit(In_sync, &rdev->flags) || rdev->recovery_offset >= end_sector)) - goto out_rcu_unlock; + return 0; } atomic_inc(&rdev->nr_pending); - rcu_read_unlock(); if (is_badblock(rdev, sector, bio_sectors(raid_bio), &first_bad, &bad_sectors)) { @@ -5576,10 +5535,6 @@ static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio) raid_bio->bi_iter.bi_sector); submit_bio_noacct(align_bio); return 1; - -out_rcu_unlock: - rcu_read_unlock(); - return 0; } static struct bio *chunk_aligned_read(struct mddev *mddev, struct bio *raid_bio) @@ -6582,14 +6537,12 @@ static inline sector_t raid5_sync_request(struct mddev *mddev, sector_t sector_n * Note in case of > 1 drive failures it's possible we're rebuilding * one drive while leaving another faulty drive in array. */ - rcu_read_lock(); for (i = 0; i < conf->raid_disks; i++) { - struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev); + struct md_rdev *rdev = conf->disks[i].rdev; if (rdev == NULL || test_bit(Faulty, &rdev->flags)) still_degraded = 1; } - rcu_read_unlock(); md_bitmap_start_sync(mddev->bitmap, sector_nr, &sync_blocks, still_degraded); @@ -6820,18 +6773,7 @@ static void raid5d(struct md_thread *thread) spin_unlock_irq(&conf->device_lock); md_check_recovery(mddev); spin_lock_irq(&conf->device_lock); - - /* - * Waiting on MD_SB_CHANGE_PENDING below may deadlock - * seeing md_check_recovery() is needed to clear - * the flag when using mdmon. - */ - continue; } - - wait_event_lock_irq(mddev->sb_wait, - !test_bit(MD_SB_CHANGE_PENDING, &mddev->sb_flags), - conf->device_lock); } pr_debug("%d stripes handled\n", handled); @@ -7911,18 +7853,10 @@ static int raid5_run(struct mddev *mddev) for (i = 0; i < conf->raid_disks && conf->previous_raid_disks; i++) { - rdev = rdev_mdlock_deref(mddev, conf->disks[i].rdev); - if (!rdev && conf->disks[i].replacement) { - /* The replacement is all we have yet */ - rdev = rdev_mdlock_deref(mddev, - conf->disks[i].replacement); - conf->disks[i].replacement = NULL; - clear_bit(Replacement, &rdev->flags); - rcu_assign_pointer(conf->disks[i].rdev, rdev); - } + rdev = conf->disks[i].rdev; if (!rdev) continue; - if (rcu_access_pointer(conf->disks[i].replacement) && + if (conf->disks[i].replacement && conf->reshape_progress != MaxSector) { /* replacements and reshape simply do not mix. */ pr_warn("md: cannot handle concurrent replacement and reshape.\n"); @@ -8106,15 +8040,16 @@ static void raid5_status(struct seq_file *seq, struct mddev *mddev) struct r5conf *conf = mddev->private; int i; + lockdep_assert_held(&mddev->lock); + seq_printf(seq, " level %d, %dk chunk, algorithm %d", mddev->level, conf->chunk_sectors / 2, mddev->layout); seq_printf (seq, " [%d/%d] [", conf->raid_disks, conf->raid_disks - mddev->degraded); - rcu_read_lock(); for (i = 0; i < conf->raid_disks; i++) { - struct md_rdev *rdev = rcu_dereference(conf->disks[i].rdev); + struct md_rdev *rdev = READ_ONCE(conf->disks[i].rdev); + seq_printf (seq, "%s", rdev && test_bit(In_sync, &rdev->flags) ? "U" : "_"); } - rcu_read_unlock(); seq_printf (seq, "]"); } @@ -8152,9 +8087,8 @@ static int raid5_spare_active(struct mddev *mddev) unsigned long flags; for (i = 0; i < conf->raid_disks; i++) { - rdev = rdev_mdlock_deref(mddev, conf->disks[i].rdev); - replacement = rdev_mdlock_deref(mddev, - conf->disks[i].replacement); + rdev = conf->disks[i].rdev; + replacement = conf->disks[i].replacement; if (replacement && replacement->recovery_offset == MaxSector && !test_bit(Faulty, &replacement->flags) @@ -8193,7 +8127,7 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev) struct r5conf *conf = mddev->private; int err = 0; int number = rdev->raid_disk; - struct md_rdev __rcu **rdevp; + struct md_rdev **rdevp; struct disk_info *p; struct md_rdev *tmp; @@ -8216,9 +8150,9 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev) if (unlikely(number >= conf->pool_size)) return 0; p = conf->disks + number; - if (rdev == rcu_access_pointer(p->rdev)) + if (rdev == p->rdev) rdevp = &p->rdev; - else if (rdev == rcu_access_pointer(p->replacement)) + else if (rdev == p->replacement) rdevp = &p->replacement; else return 0; @@ -8238,37 +8172,24 @@ static int raid5_remove_disk(struct mddev *mddev, struct md_rdev *rdev) if (!test_bit(Faulty, &rdev->flags) && mddev->recovery_disabled != conf->recovery_disabled && !has_failed(conf) && - (!rcu_access_pointer(p->replacement) || - rcu_access_pointer(p->replacement) == rdev) && + (!p->replacement || p->replacement == rdev) && number < conf->raid_disks) { err = -EBUSY; goto abort; } - *rdevp = NULL; - if (!test_bit(RemoveSynchronized, &rdev->flags)) { - lockdep_assert_held(&mddev->reconfig_mutex); - synchronize_rcu(); - if (atomic_read(&rdev->nr_pending)) { - /* lost the race, try later */ - err = -EBUSY; - rcu_assign_pointer(*rdevp, rdev); - } - } + WRITE_ONCE(*rdevp, NULL); if (!err) { err = log_modify(conf, rdev, false); if (err) goto abort; } - tmp = rcu_access_pointer(p->replacement); + tmp = p->replacement; if (tmp) { /* We must have just cleared 'rdev' */ - rcu_assign_pointer(p->rdev, tmp); + WRITE_ONCE(p->rdev, tmp); clear_bit(Replacement, &tmp->flags); - smp_mb(); /* Make sure other CPUs may see both as identical - * but will never see neither - if they are careful - */ - rcu_assign_pointer(p->replacement, NULL); + WRITE_ONCE(p->replacement, NULL); if (!err) err = log_modify(conf, tmp, true); @@ -8336,7 +8257,7 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev) rdev->raid_disk = disk; if (rdev->saved_raid_disk != disk) conf->fullsync = 1; - rcu_assign_pointer(p->rdev, rdev); + WRITE_ONCE(p->rdev, rdev); err = log_modify(conf, rdev, true); @@ -8345,7 +8266,7 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev) } for (disk = first; disk <= last; disk++) { p = conf->disks + disk; - tmp = rdev_mdlock_deref(mddev, p->rdev); + tmp = p->rdev; if (test_bit(WantReplacement, &tmp->flags) && mddev->reshape_position == MaxSector && p->replacement == NULL) { @@ -8354,7 +8275,7 @@ static int raid5_add_disk(struct mddev *mddev, struct md_rdev *rdev) rdev->raid_disk = disk; err = 0; conf->fullsync = 1; - rcu_assign_pointer(p->replacement, rdev); + WRITE_ONCE(p->replacement, rdev); break; } } @@ -8487,7 +8408,7 @@ static int raid5_start_reshape(struct mddev *mddev) if (mddev->recovery_cp < MaxSector) return -EBUSY; for (i = 0; i < conf->raid_disks; i++) - if (rdev_mdlock_deref(mddev, conf->disks[i].replacement)) + if (conf->disks[i].replacement) return -EBUSY; rdev_for_each(rdev, mddev) { @@ -8658,12 +8579,10 @@ static void raid5_finish_reshape(struct mddev *mddev) for (d = conf->raid_disks ; d < conf->raid_disks - mddev->delta_disks; d++) { - rdev = rdev_mdlock_deref(mddev, - conf->disks[d].rdev); + rdev = conf->disks[d].rdev; if (rdev) clear_bit(In_sync, &rdev->flags); - rdev = rdev_mdlock_deref(mddev, - conf->disks[d].replacement); + rdev = conf->disks[d].replacement; if (rdev) clear_bit(In_sync, &rdev->flags); } |