Messages in this thread | | | From | Jes Sorensen <> | Subject | Re: [PATCH 3.10 49/53] md/raid5: Fix livelock when array is both resyncing and degraded. | Date | Wed, 04 Mar 2015 09:09:52 -0500 |
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Greg Kroah-Hartman <gregkh@linuxfoundation.org> writes: > 3.10-stable review patch. If anyone has any objections, please let me know. > > ------------------
For all 4 stable branches:
Acked-by: Jes Sorensen <Jes.Sorensen@redhat.com>
> > 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 > @@ -2853,7 +2853,8 @@ 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 > */
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