tree 13d6696f82a1cb43c77172d5782fce31665bd40c
parent cac7f2429872d3733dc3f9915857b1691da2eb2f
author Jan Kara <jack@suse.cz> 1414680777 -0400
committer Theodore Ts'o <tytso@mit.edu> 1414680777 -0400

ext4: fix overflow when updating superblock backups after resize

When there are no meta block groups update_backups() will compute the
backup block in 32-bit arithmetics thus possibly overflowing the block
number and corrupting the filesystem. OTOH filesystems without meta
block groups larger than 16 TB should be rare. Fix the problem by doing
the counting in 64-bit arithmetics.

Coverity-id: 741252
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>