tree 2af8bd9feeb23f1bd847159397360ca256a8bc1d
parent 3c26bdb42320f9f39d30c6f115476bbb66b74dc5
author Tao Ma <boyu.mt@taobao.com> 1299164317 +0800
committer Jan Kara <jack@suse.cz> 1299195255 +0100

ext3: Fix an overflow in ext3_trim_fs.

In a bs=4096 volume, if we call FITRIM with the following parameter as
fstrim_range(start = 102400, len = 134144000, minlen = 10240), with the
following code:
if (len >= EXT3_BLOCKS_PER_GROUP(sb))
        len -= (EXT3_BLOCKS_PER_GROUP(sb) - first_block);
else
        last_block = first_block + len;

So if len < EXT3_BLOCKS_PER_GROUP while first_block + len >
EXT3_BLOCKS_PER_GROUP, last_block will be set to an overflow value
which exceeds EXT3_BLOCKS_PER_GROUP.

This patch fixes it and adjusts len and last_block accordingly.

Cc: Lukas Czerner <lczerner@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>