[ 115/149] ext4: check for zero length extent
From: Greg KH
Date: Fri Mar 30 2012 - 17:14:50 EST
3.2-stable review patch. If anyone has any objections, please let me know.
From: Theodore Ts'o <tytso@xxxxxxx>
commit 31d4f3a2f3c73f279ff96a7135d7202ef6833f12 upstream.
Explicitly test for an extent whose length is zero, and flag that as a
This avoids a kernel BUG_ON assertion failure.
Tested: Without this patch, the file system image found in
tests/f_ext_zero_len/image.gz in the latest e2fsprogs sources causes a
kernel panic. With this patch, an ext4 file system error is noted
instead, and the file system is marked as being corrupted.
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
fs/ext4/extents.c | 2 ++
1 file changed, 2 insertions(+)
@@ -301,6 +301,8 @@ static int ext4_valid_extent(struct inod
ext4_fsblk_t block = ext4_ext_pblock(ext);
int len = ext4_ext_get_actual_len(ext);
+ if (len == 0)
+ return 0;
return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
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