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Commit 43090805 authored by Nigel Croxon's avatar Nigel Croxon Committed by Greg Kroah-Hartman
Browse files

md/raid: raid5 preserve the writeback action after the parity check 



commit b2176a1dfb518d870ee073445d27055fea64dfb8 upstream.

The problem is that any 'uptodate' vs 'disks' check is not precise
in this path. Put a "WARN_ON(!test_bit(R5_UPTODATE, &dev->flags)" on the
device that might try to kick off writes and then skip the action.
Better to prevent the raid driver from taking unexpected action *and* keep
the system alive vs killing the machine with BUG_ON.

Note: fixed warning reported by kbuild test robot <lkp@intel.com>

Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarNigel Croxon <ncroxon@redhat.com>
Signed-off-by: default avatarSong Liu <songliubraving@fb.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3d25b7f5

drivers/md/raid5.c

+9 −1
Original line number Diff line number Diff line
@@ -4185,7 +4185,7 @@ static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh, 
		/* now write out any block on a failed drive,

		 * or P or Q if they were recomputed

		 */

		BUG_ON(s->uptodate < disks - 1); /* We don't need Q to recover */

		dev = NULL;

		if (s->failed == 2) {

			dev = &sh->dev[s->failed_num[1]];

			s->locked++;
@@ -4210,6 +4210,14 @@ static void handle_parity_checks6(struct r5conf *conf, struct stripe_head *sh, 
			set_bit(R5_LOCKED, &dev->flags);

			set_bit(R5_Wantwrite, &dev->flags);

		}

		if (WARN_ONCE(dev && !test_bit(R5_UPTODATE, &dev->flags),

			      "%s: disk%td not up to date\n",

			      mdname(conf->mddev),

			      dev - (struct r5dev *) &sh->dev)) {

			clear_bit(R5_LOCKED, &dev->flags);

			clear_bit(R5_Wantwrite, &dev->flags);

			s->locked--;

		}

		clear_bit(STRIPE_DEGRADED, &sh->state);



		set_bit(STRIPE_INSYNC, &sh->state);