From 2f974865ffdfe7b9f46a9940836c8b167342563d Mon Sep 17 00:00:00 2001 From: Eryu Guan Date: Thu, 14 May 2015 19:00:45 -0400 Subject: [PATCH] ext4: check for zero length extent explicitly 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 Signed-off-by: Theodore Ts'o Cc: stable@vger.kernel.org --- 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 d74e08029643..451b92a9958a 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -377,7 +377,7 @@ 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); }