commit 105ddc93f06ebe3e553f58563d11ed63dbcd59f0
author Ashish Samant <ashish.samant@oracle.com> Thu Nov 02 15:59:37 2017 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> Fri Nov 03 07:39:19 2017 -0700
tree 40516332f788df92c2d7c1304f81c8f674aa76b0
parent b83d7e432399d44454411dec5c25afb5c4469e96

ocfs2: fstrim: Fix start offset of first cluster group during fstrim

The first cluster group descriptor is not stored at the start of the
group but at an offset from the start.  We need to take this into
account while doing fstrim on the first cluster group.  Otherwise we
will wrongly start fstrim a few blocks after the desired start block and
the range can cross over into the next cluster group and zero out the
group descriptor there.  This can cause filesytem corruption that cannot
be fixed by fsck.

Link: http://lkml.kernel.org/r/1507835579-7308-1-git-send-email-ashish.samant@oracle.com
Signed-off-by: Ashish Samant <ashish.samant@oracle.com>
Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com>
Reviewed-by: Joseph Qi <jiangqi903@gmail.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>