From 4eb3991c5def39bcf553c14ebe2618fcb47b627f Mon Sep 17 00:00:00 2001
From: Dan Carpenter <error27@gmail.com>
Date: Tue, 10 Nov 2009 09:01:43 +0000
Subject: Btrfs: avoid null deref in unpin_extent_cache()

I re-orderred the checks to avoid dereferencing "em" if it was null.

Found by smatch static checker.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
---
 fs/btrfs/extent_map.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'fs/btrfs')

diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 2c726b7..ccbdcb5 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -208,7 +208,7 @@ int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len)
 	write_lock(&tree->lock);
 	em = lookup_extent_mapping(tree, start, len);
 
-	WARN_ON(em->start != start || !em);
+	WARN_ON(!em || em->start != start);
 
 	if (!em)
 		goto out;
-- 
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