Btrfs: check range early in map_private_extent_buffer
From: Wang Sheng-Hui
Date: Mon Sep 24 2012 - 00:38:21 EST
Check range early to avoid further check/compute in case
of range error.
Signed-off-by: Wang Sheng-Hui <shhuiw@xxxxxxxxx>
---
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
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