| From | lizf@kernel ... | Subject | [PATCH 3.4 096/146] ext4: check for zero length extent explicitly | Date | Tue, 15 Sep 2015 17:03:31 +0800 |
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From: Eryu Guan <guaneryu@gmail.com>
3.4.109-rc1 review patch. If anyone has any objections, please let me know.
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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@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Zefan Li <lizefan@huawei.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 bb72833..bbe09a9 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -320,7 +320,7 @@ 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); } -- 1.9.1
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