| From 26ac107378c4742978216be1005b7291b799c7b2 Mon Sep 17 00:00:00 2001 |
| From: NeilBrown <neilb@suse.de> |
| Date: Wed, 18 Feb 2015 11:35:14 +1100 |
| Subject: md/raid5: Fix livelock when array is both resyncing and degraded. |
| |
| From: NeilBrown <neilb@suse.de> |
| |
| 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@amiindia.co.in> |
| Bisected-by: Jes Sorensen <Jes.Sorensen@redhat.com> |
| Tested-by: Jes Sorensen <Jes.Sorensen@redhat.com> |
| Signed-off-by: NeilBrown <neilb@suse.de> |
| Fixes: a7854487cd7128a30a7f4f5259de9f67d5efb95f |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/md/raid5.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/drivers/md/raid5.c |
| +++ b/drivers/md/raid5.c |
| @@ -3102,7 +3102,8 @@ 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 |
| */ |
