This is a note to let you know that I've just added the patch titled md/raid5: Fix livelock when array is both resyncing and degraded. to the 3.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: md-raid5-fix-livelock-when-array-is-both-resyncing-and-degraded.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 26ac107378c4742978216be1005b7291b799c7b2 Mon Sep 17 00:00:00 2001 From: NeilBrown <neilb@xxxxxxx> Date: Wed, 18 Feb 2015 11:35:14 +1100 Subject: md/raid5: Fix livelock when array is both resyncing and degraded. From: NeilBrown <neilb@xxxxxxx> commit 26ac107378c4742978216be1005b7291b799c7b2 upstream. Commit a7854487cd7128a30a7f4f5259de9f67d5efb95f: md: When RAID5 is dirty, force reconstruct-write instead of read-modify-write. Causes an RCW cycle to be forced even when the array is degraded. A degraded array cannot support RCW as that requires reading all data blocks, and one may be missing. Forcing an RCW when it is not possible causes a live-lock and the code spins, repeatedly deciding to do something that cannot succeed. So change the condition to only force RCW on non-degraded arrays. Reported-by: Manibalan P <pmanibalan@xxxxxxxxxxxxxx> Bisected-by: Jes Sorensen <Jes.Sorensen@xxxxxxxxxx> Tested-by: Jes Sorensen <Jes.Sorensen@xxxxxxxxxx> Signed-off-by: NeilBrown <neilb@xxxxxxx> Fixes: a7854487cd7128a30a7f4f5259de9f67d5efb95f Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/md/raid5.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -3071,7 +3071,8 @@ static void handle_stripe_dirtying(struc * generate correct data from the parity. */ if (conf->max_degraded == 2 || - (recovery_cp < MaxSector && sh->sector >= recovery_cp)) { + (recovery_cp < MaxSector && sh->sector >= recovery_cp && + s->failed == 0)) { /* Calculate the real rcw later - for now make it * look like rcw is cheaper */ Patches currently in stable-queue which might be from neilb@xxxxxxx are queue-3.14/md-raid5-fix-livelock-when-array-is-both-resyncing-and-degraded.patch queue-3.14/md-raid1-fix-read-balance-when-a-drive-is-write-mostly.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html