diff options
| -rw-r--r-- | drivers/md/raid5.c | 29 |
1 files changed, 23 insertions, 6 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 0ee9aa0113f3..e248532bb70a 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5403,6 +5403,7 @@ static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio) sector_t sector, end_sector, first_bad; int bad_sectors, dd_idx; struct md_io_acct *md_io_acct; + bool did_inc; if (!in_chunk_boundary(mddev, raid_bio)) { pr_debug("%s: non aligned\n", __func__); @@ -5454,11 +5455,24 @@ static int raid5_read_one_chunk(struct mddev *mddev, struct bio *raid_bio) /* No reshape active, so we can trust rdev->data_offset */ align_bio->bi_iter.bi_sector += rdev->data_offset; - spin_lock_irq(&conf->device_lock); - wait_event_lock_irq(conf->wait_for_quiescent, conf->quiesce == 0, - conf->device_lock); - atomic_inc(&conf->active_aligned_reads); - spin_unlock_irq(&conf->device_lock); + did_inc = false; + if (conf->quiesce == 0) { + atomic_inc(&conf->active_aligned_reads); + did_inc = true; + } + /* need a memory barrier to detect the race with raid5_quiesce() */ + if (!did_inc || smp_load_acquire(&conf->quiesce) != 0) { + /* quiesce is in progress, so we need to undo io activation and wait + * for it to finish + */ + if (did_inc && atomic_dec_and_test(&conf->active_aligned_reads)) + wake_up(&conf->wait_for_quiescent); + spin_lock_irq(&conf->device_lock); + wait_event_lock_irq(conf->wait_for_quiescent, conf->quiesce == 0, + conf->device_lock); + atomic_inc(&conf->active_aligned_reads); + spin_unlock_irq(&conf->device_lock); + } if (mddev->gendisk) trace_block_bio_remap(align_bio, disk_devt(mddev->gendisk), @@ -8346,7 +8360,10 @@ static void raid5_quiesce(struct mddev *mddev, int quiesce) * active stripes can drain */ r5c_flush_cache(conf, INT_MAX); - conf->quiesce = 2; + /* need a memory barrier to make sure read_one_chunk() sees + * quiesce started and reverts to slow (locked) path. + */ + smp_store_release(&conf->quiesce, 2); wait_event_cmd(conf->wait_for_quiescent, atomic_read(&conf->active_stripes) == 0 && atomic_read(&conf->active_aligned_reads) == 0, |