linux-kernel - Re: [patch v2] fs: umount on symlinlk leaks mnt count

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Message-ID: <CAFLxGvxf_bsLNKRtt05zgkdHy+7ALWMz29QUG=f9UwTcqXetfg@mail.gmail.com>
Date:	Sun, 20 Jul 2014 12:48:02 +0200
From:	Richard Weinberger <richard.weinberger@...il.com>
To:	Vasily Averin <vvs@...allels.com>
Cc:	Alexander Viro <viro@...iv.linux.org.uk>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [patch v2] fs: umount on symlinlk leaks mnt count

On Sun, Jul 20, 2014 at 9:32 AM, Vasily Averin <vvs@...allels.com> wrote:
> v2: mntget(path->mnt) should not be called if mountpoint_last() returns 1.
>
> Currently umount on symlink blocks following umount:
>
> /vz is separate mount
>
> # ls /vz/ -al | grep test
> drwxr-xr-x.  2 root root       4096 Jul 19 01:14 testdir
> lrwxrwxrwx.  1 root root         11 Jul 19 01:16 testlink -> /vz/testdir
>
> # umount -l /vz/testlink
> umount: /vz/testlink: not mounted (expected)
>
> # lsof /vz
> # umount /vz
> umount: /vz: device is busy. (unexpected)
>
> In this case mountpoint_last() gets an extra refcount on path->mnt
>
> Signed-off-by:  Vasily Averin <vvs@...nvz.org>

Sounds reasonable to me.
Can you please send the patch inline and not as attachment?

-- 
Thanks,
//richard
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