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authorNeilBrown <neilb@suse.de>2014-01-14 15:16:10 +1100
committerNeilBrown <neilb@suse.de>2014-01-14 16:44:07 +1100
commit5af9bef72c074dbe946da8b74eabd79cd5a9ff19 (patch)
treed2572106b3e41964a96dbf0fe71f4c22e486802d /drivers/md
parent41a336e011887f73e7c879b60e1e3544045435cb (diff)
downloadlinux-5af9bef72c074dbe946da8b74eabd79cd5a9ff19.tar.bz2
md/raid5: fix a recently broken BUG_ON().
commit 6d183de4077191d1201283a9035ce57a9b05254d md/raid5: fix newly-broken locking in get_active_stripe. simplified a BUG_ON, but removed too much so now it sometimes fires when it shouldn't. When the STRIPE_EXPANDING flag is set, the stripe_head might be on a special list while multiple stripe_heads are collected, or it might not be on any list, even a 'free' list when the refcount is zero. As long as STRIPE_EXPANDING is set, it will be found and added back to a list eventually. So both of the BUG_ONs which test for the ->lru being empty or not need to avoid the case where STRIPE_EXPANDING is set. The patch which broke this was marked for -stable, so this patch needs to be applied to any branch that received 6d183de4 Fixes: 6d183de4077191d1201283a9035ce57a9b05254d Cc: stable@vger.kernel.org (any release to which above was applied) Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/raid5.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 9168173deaf3..cbb15716a5db 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -687,7 +687,8 @@ get_active_stripe(struct r5conf *conf, sector_t sector,
} else {
if (!test_bit(STRIPE_HANDLE, &sh->state))
atomic_inc(&conf->active_stripes);
- BUG_ON(list_empty(&sh->lru));
+ BUG_ON(list_empty(&sh->lru) &&
+ !test_bit(STRIPE_EXPANDING, &sh->state));
list_del_init(&sh->lru);
if (sh->group) {
sh->group->stripes_cnt--;