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Message-Id: <1071022071550.31281@suse.de>
Date: Mon, 22 Oct 2007 17:15:50 +1000
From: NeilBrown <neilb@...e.de>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Stable <stable@...nel.org>
Subject: [PATCH 002 of 2] md: raid5: fix clearing of biofill operations
From: Dan Williams <dan.j.williams@...el.com>
ops_complete_biofill() runs outside of spin_lock(&sh->lock) and clears the
'pending' and 'ack' bits. Since the test_and_ack_op() macro only checks
against 'complete' it can get an inconsistent snapshot of pending work.
Move the clearing of these bits to handle_stripe5(), under the lock.
Signed-off-by: Dan Williams <dan.j.williams@...el.com>
Tested-by: Joël Bertrand <joel.bertrand@...tella.fr>
Signed-off-by: Neil Brown <neilb@...e.de>
Cc: Stable <stable@...nel.org>
### Diffstat output
./drivers/md/raid5.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
diff .prev/drivers/md/raid5.c ./drivers/md/raid5.c
--- .prev/drivers/md/raid5.c 2007-10-22 16:55:49.000000000 +1000
+++ ./drivers/md/raid5.c 2007-10-22 16:57:41.000000000 +1000
@@ -665,7 +665,12 @@ static unsigned long get_stripe_work(str
ack++;
sh->ops.count -= ack;
- BUG_ON(sh->ops.count < 0);
+ if (unlikely(sh->ops.count < 0)) {
+ printk(KERN_ERR "pending: %#lx ops.pending: %#lx ops.ack: %#lx "
+ "ops.complete: %#lx\n", pending, sh->ops.pending,
+ sh->ops.ack, sh->ops.complete);
+ BUG();
+ }
return pending;
}
@@ -842,8 +847,7 @@ static void ops_complete_biofill(void *s
}
}
}
- clear_bit(STRIPE_OP_BIOFILL, &sh->ops.ack);
- clear_bit(STRIPE_OP_BIOFILL, &sh->ops.pending);
+ set_bit(STRIPE_OP_BIOFILL, &sh->ops.complete);
return_io(return_bi);
@@ -3130,6 +3134,13 @@ static void handle_stripe5(struct stripe
s.expanded = test_bit(STRIPE_EXPAND_READY, &sh->state);
/* Now to look around and see what can be done */
+ /* clean-up completed biofill operations */
+ if (test_bit(STRIPE_OP_BIOFILL, &sh->ops.complete)) {
+ clear_bit(STRIPE_OP_BIOFILL, &sh->ops.pending);
+ clear_bit(STRIPE_OP_BIOFILL, &sh->ops.ack);
+ clear_bit(STRIPE_OP_BIOFILL, &sh->ops.complete);
+ }
+
rcu_read_lock();
for (i=disks; i--; ) {
mdk_rdev_t *rdev;
-
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