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    SubjectRe: [PATCH v4] fs: umount on symlink leaks mnt count
    On Mon, 21 Jul 2014 12:30:23 +0400
    Vasily Averin <vvs@parallels.com> wrote:

    > v4: description corrected
    > v3: patch inline
    >
    > 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@openvz.org>
    > ---
    > fs/namei.c | 3 ++-
    > 1 files changed, 2 insertions(+), 1 deletions(-)
    >
    > diff --git a/fs/namei.c b/fs/namei.c
    > index 985c6f3..9eb787e 100644
    > --- a/fs/namei.c
    > +++ b/fs/namei.c
    > @@ -2256,9 +2256,10 @@ done:
    > goto out;
    > }
    > path->dentry = dentry;
    > - path->mnt = mntget(nd->path.mnt);
    > + path->mnt = nd->path.mnt;
    > if (should_follow_link(dentry, nd->flags & LOOKUP_FOLLOW))
    > return 1;
    > + mntget(path->mnt);
    > follow_mount(path);
    > error = 0;
    > out:

    Looks correct, I think...

    Acked-by:
    --
    Jeff Layton <jlayton@primarydata.com>


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