| From 31d4f3a2f3c73f279ff96a7135d7202ef6833f12 Mon Sep 17 00:00:00 2001 |
| From: Theodore Ts'o <tytso@mit.edu> |
| Date: Sun, 11 Mar 2012 23:30:16 -0400 |
| Subject: ext4: check for zero length extent |
| |
| From: Theodore Ts'o <tytso@mit.edu> |
| |
| commit 31d4f3a2f3c73f279ff96a7135d7202ef6833f12 upstream. |
| |
| Explicitly test for an extent whose length is zero, and flag that as a |
| corrupted extent. |
| |
| 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. |
| |
| https://bugzilla.kernel.org/show_bug.cgi?id=42859 |
| |
| Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/ext4/extents.c | 2 ++ |
| 1 file changed, 2 insertions(+) |
| |
| --- a/fs/ext4/extents.c |
| +++ b/fs/ext4/extents.c |
| @@ -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); |
| } |
| |
