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| author | Shaohua Li <shli@fb.com> | 2016-02-26 03:24:42 +0300 |
|---|---|---|
| committer | Shaohua Li <shli@fb.com> | 2016-02-26 20:44:56 +0300 |
| commit | 6ab2a4b806ae21b6c3e47c5ff1285ec06d505325 (patch) | |
| tree | 881693ece12cd8ce147f1a370370eb60928120b0 /drivers/md/raid5.h | |
| parent | 27a353c026a879a1001e5eac4bda75b16262c44a (diff) | |
| download | linux-6ab2a4b806ae21b6c3e47c5ff1285ec06d505325.tar.xz | |
RAID5: revert e9e4c377e2f563 to fix a livelock
Revert commit
e9e4c377e2f563(md/raid5: per hash value and exclusive wait_for_stripe)
The problem is raid5_get_active_stripe waits on
conf->wait_for_stripe[hash]. Assume hash is 0. My test release stripes
in this order:
- release all stripes with hash 0
- raid5_get_active_stripe still sleeps since active_stripes >
max_nr_stripes * 3 / 4
- release all stripes with hash other than 0. active_stripes becomes 0
- raid5_get_active_stripe still sleeps, since nobody wakes up
wait_for_stripe[0]
The system live locks. The problem is active_stripes isn't a per-hash
count. Revert the patch makes the live lock go away.
Cc: stable@vger.kernel.org (v4.2+)
Cc: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Cc: NeilBrown <neilb@suse.de>
Signed-off-by: Shaohua Li <shli@fb.com>
Diffstat (limited to 'drivers/md/raid5.h')
| -rw-r--r-- | drivers/md/raid5.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index ae6068deefdf..517d4b68a1be 100644 --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -524,7 +524,7 @@ struct r5conf { atomic_t empty_inactive_list_nr; struct llist_head released_stripes; wait_queue_head_t wait_for_quiescent; - wait_queue_head_t wait_for_stripe[NR_STRIPE_HASH_LOCKS]; + wait_queue_head_t wait_for_stripe; wait_queue_head_t wait_for_overlap; unsigned long cache_state; #define R5_INACTIVE_BLOCKED 1 /* release of inactive stripes blocked, |