ext4: fix corruption when online resizing a fs with 1K block size
authorMaarten ter Huurne <maarten@treewalker.org>
Mon, 1 Jul 2013 12:12:08 +0000 (08:12 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 22 Jul 2013 01:21:23 +0000 (18:21 -0700)
commitb6a81140efa3b994f3bde4ea48434cfc6e5d4fe9
treee3a2116ad5df6124662a3f15bf15c2d4c4fa5fa4
parent15f26a4c4820d1fb5f1ba979b4fe4d00a2d38b7d
ext4: fix corruption when online resizing a fs with 1K block size

commit 6ca792edc13c409e8d4eb9001e048264c6a2eb64 upstream.

Subtracting the number of the first data block places the superblock
backups one block too early, corrupting the file system. When the block
size is larger than 1K, the first data block is 0, so the subtraction
has no effect and no corruption occurs.

Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fs/ext4/resize.c