Commit 1cc03eb9 authored Jan 06, 2014 by NeilBrown

md/raid5: Fix possible confusion when multiple write errors occur.



commit 5d8c71f9
    md: raid5 crash during degradation

Fixed a crash in an overly simplistic way which could leave
R5_WriteError or R5_MadeGood set in the stripe cache for devices
for which it is no longer relevant.
When those devices are removed and spares added the flags are still
set and can cause incorrect behaviour.

commit 14a75d3e
    md/raid5: preferentially read from replacement device if possible.

Fixed the same bug if a more effective way, so we can now revert
the original commit.

Reported-and-tested-by: Alexander Lyakas <alex.bolshoy@gmail.com>
Cc: stable@vger.kernel.org (3.2+ - 3.2 will need a different fix though)
Fixes: 5d8c71f9
Signed-off-by: NeilBrown <neilb@suse.de>

parent 6d183de4

drivers/md/raid5.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -3608,7 +3608,7 @@ static void analyse_stripe(struct stripe_head sh, struct stripe_head_state s)
		*/
		set_bit(R5_Insync, &dev->flags);

		if (rdev && test_bit(R5_WriteError, &dev->flags)) {
		if (test_bit(R5_WriteError, &dev->flags)) {
		/* This flag does not apply to '.replacement'
		* only to .rdev, so make sure to check that*/
		struct md_rdev *rdev2 = rcu_dereference(
		@@ -3621,7 +3621,7 @@ static void analyse_stripe(struct stripe_head sh, struct stripe_head_state s)
		} else
		clear_bit(R5_WriteError, &dev->flags);
		}
		if (rdev && test_bit(R5_MadeGood, &dev->flags)) {
		if (test_bit(R5_MadeGood, &dev->flags)) {
		/* This flag does not apply to '.replacement'
		* only to .rdev, so make sure to check that*/
		struct md_rdev *rdev2 = rcu_dereference(