tree 9c33ad74ee35181cb6d1a2e82da8df110919e47c
parent 0a2179b169089f871e071c74316371ed43e6c8eb
author Jan Kara <jack@suse.cz> 1294776991 -0500
committer Theodore Ts'o <tytso@mit.edu> 1294776991 -0500

ext4: fix trimming starting with block 0 with small blocksize

When s_first_data_block is not zero (which happens e.g. when block size is 1KB)
and trim ioctl is called to start trimming from block 0, the math in
ext4_get_group_no_and_offset() overflows. The overall result is that ioctl
returns EINVAL which is kind of unexpected and we probably don't want
userspace tools to bother with internal details of filesystem structure.
So just silently increase starting offset (and shorten length) when starting
block is below s_first_data_block.

CC: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>