[PATCH 3.16.y-ckt 042/110] ext4: check for zero length extent explicitly
Luis Henriques
luis.henriques at canonical.com
Fri Jun 5 13:57:25 UTC 2015
3.16.7-ckt13 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Eryu Guan <guaneryu at gmail.com>
commit 2f974865ffdfe7b9f46a9940836c8b167342563d upstream.
The following commit introduced a bug when checking for zero length extent
5946d08 ext4: check for overlapping extents in ext4_valid_extent_entries()
Zero length extent could pass the check if lblock is zero.
Adding the explicit check for zero length back.
Signed-off-by: Eryu Guan <guaneryu at gmail.com>
Signed-off-by: Theodore Ts'o <tytso at mit.edu>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
fs/ext4/extents.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 99d74306e770..a2c5bb7e71bb 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -361,7 +361,7 @@ static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
ext4_lblk_t lblock = le32_to_cpu(ext->ee_block);
ext4_lblk_t last = lblock + len - 1;
- if (lblock > last)
+ if (len == 0 || lblock > last)
return 0;
return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
}
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