From: Liu Bo <liubo2009@cn.fujitsu.com>
Date: Thu, 9 Feb 2012 10:17:41 +0000 (+0800)
Subject: Btrfs: fix trim 0 bytes after a device delete
X-Git-Tag: v3.3-rc5~9^2~19
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2cac13e41bf5b99ffc426bd28dfd2248df1dfa67;p=pandora-kernel.git

Btrfs: fix trim 0 bytes after a device delete

A user reported a bug of btrfs's trim, that is we will trim 0 bytes
after a device delete.

The reproducer:

$ mkfs.btrfs disk1
$ mkfs.btrfs disk2
$ mount disk1 /mnt
$ fstrim -v /mnt
$ btrfs device add disk2 /mnt
$ btrfs device del disk1 /mnt
$ fstrim -v /mnt

This is because after we delete the device, the block group may start from
a non-zero place, which will confuse trim to discard nothing.

Reported-by: Lutz Euler <lutz.euler@freenet.de>
Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
---

Reading git-diff-tree failed