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* Btrfs: check range early in map_private_extent_buffer
@ 2012-09-24  4:38 Wang Sheng-Hui
  2012-09-24 16:17 ` David Sterba
  0 siblings, 1 reply; 3+ messages in thread
From: Wang Sheng-Hui @ 2012-09-24  4:38 UTC (permalink / raw)
  To: chris.mason, jbacik, linux-btrfs, linux-kernel

Check range early to avoid further check/compute in case
of range error.

Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
---
 fs/btrfs/extent_io.c |   16 ++++++++--------
 1 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 4c87847..9250cf5 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4643,6 +4643,14 @@ int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
 	unsigned long end_i = (start_offset + start + min_len - 1) >>
 		PAGE_CACHE_SHIFT;
 
+	if (start + min_len > eb->len) {
+		printk(KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
+		       "wanted %lu %lu\n", (unsigned long long)eb->start,
+		       eb->len, start, min_len);
+		WARN_ON(1);
+		return -EINVAL;
+	}
+
 	if (i != end_i)
 		return -EINVAL;
 
@@ -4654,14 +4662,6 @@ int map_private_extent_buffer(struct extent_buffer *eb, unsigned long start,
 		*map_start = ((u64)i << PAGE_CACHE_SHIFT) - start_offset;
 	}
 
-	if (start + min_len > eb->len) {
-		printk(KERN_ERR "btrfs bad mapping eb start %llu len %lu, "
-		       "wanted %lu %lu\n", (unsigned long long)eb->start,
-		       eb->len, start, min_len);
-		WARN_ON(1);
-		return -EINVAL;
-	}
-
 	p = extent_buffer_page(eb, i);
 	kaddr = page_address(p);
 	*map = kaddr + offset;
-- 
1.7.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2012-09-25  0:24 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2012-09-24  4:38 Btrfs: check range early in map_private_extent_buffer Wang Sheng-Hui
2012-09-24 16:17 ` David Sterba
2012-09-25  0:24   ` Wang Sheng-Hui

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