md: raid5: fix clearing of biofill operations (4ae3f847) · Commits · 戴 / test

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@intel.com> Tested-by:

Joel Bertrand <joel.bertrand@systella.fr> Signed-off-by:

Neil Brown <neilb@suse.de> Cc: Stable <stable@kernel.org> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

drivers/md/raid5.c

+14 −3

Original line number	Diff line number	Diff line
		@@ -376,7 +376,12 @@ static unsigned long get_stripe_work(struct stripe_head *sh)
		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;
		}
		@@ -550,8 +555,7 @@ static void ops_complete_biofill(void *stripe_head_ref)
		}
		}
		}
		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);

		@@ -2893,6 +2897,13 @@ static void handle_stripe6(struct stripe_head sh, struct page tmp_page)
		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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