redonkable
/
alistair23-linux
1
0
Fork 0
Code Releases Activity

md/raid5: Fix livelock when array is both resyncing and degraded. 

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: a7854487cd
Cc: stable@vger.kernel.org (v3.7+)
hifive-unleashed-5.1
NeilBrown 2015-02-18 11:35:14 +11:00
parent f04ebb0be7
commit 26ac107378
1 changed files with 2 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/md/raid5.c
View File

@ -3170,7 +3170,8 @@ static void handle_stripe_dirtying(struct r5conf *conf,
* 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
*/