From: Li Zefan <lizf@cn.fujitsu.com>
Date: Wed, 7 Dec 2011 03:38:24 +0000 (+0800)
Subject: Btrfs: fix possible deadlock when opening a seed device
X-Git-Tag: v3.3-rc1~26^2~11^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b367e47fb3a70f5d24ebd6faf7d42436d485fb2d;p=pandora-kernel.git

Btrfs: fix possible deadlock when opening a seed device

The correct lock order is uuid_mutex -> volume_mutex -> chunk_mutex,
but when we mount a filesystem which has backing seed devices, we have
this lock chain:

    open_ctree()
        lock(chunk_mutex);
        read_chunk_tree();
            read_one_dev();
                open_seed_devices();
                    lock(uuid_mutex);

and then we hit a lockdep splat.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---

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