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From: Jonathan Brassow <jbrassow@redhat.com>
To: dm-devel@redhat.com
Date: Fri, 20 Feb 2009 17:28:35 -0600
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Subject: [dm-devel] [PATCH 13 of 17] dm-snap-possible-code-optimization.patch
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Minor code clean-up.  The reason I broke this out into a separate
patch is so people can check if I'm not missing anything...  I
don't see a reason to check 's->valid' separately anymore.

RFC-by: Jonathan Brassow <jbrassow@redhat.com>
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Index: linux-2.6/drivers/md/dm-snap.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-snap.c
+++ linux-2.6/drivers/md/dm-snap.c
@@ -740,20 +740,14 @@ static void pending_complete(struct dm_s
 	struct bio *snapshot_bios = NULL;
 	int error = 0;
 
+	down_write(&s->lock);
 	if (!success) {
 		/* Read/write error - snapshot is unusable */
-		down_write(&s->lock);
 		__invalidate_snapshot(s, -EIO);
 		error = 1;
 		goto out;
 	}
 
-	down_write(&s->lock);
-	if (!s->valid) {
-		error = 1;
-		goto out;
-	}
-
 	/*
 	 * Check for conflicting reads. This is extremely improbable,
 	 * so msleep(1) is sufficient and there is no need for a wait queue.