linux-kernel - Re: [PATCH] autofs - fix symlinks aren't checked for expiry

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Date:	Fri, 27 Dec 2013 11:53:40 +0100
From:	Sedat Dilek <sedat.dilek@...il.com>
To:	Ian Kent <raven@...maw.net>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>,
	autofs mailing list <autofs@...r.kernel.org>,
	Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] autofs - fix symlinks aren't checked for expiry

On Fri, Dec 27, 2013 at 5:32 AM, Ian Kent <raven@...maw.net> wrote:

Hi,

saw some typos...

> From: Ian Kent <ikent@...hat.com>
>
> The autofs4 module doesn't consider symlinks for expire as it did
> in the older autofs v3 module (so it's actually a long stnding

s/stnding/standing

> regression).
>
> The user space daemon has focused on the use of bind mounts instead
> of symlinks for a long time now and that's why this has not been
> noticed. But with the future addition of amd map parsing to
> automount(8), not to mention amd itself (of am-utils), symlink
> expiry will be needed.
>
> The direct and offset mount types can't be symlinks and the tree
> mounts of version 4 were always real mounts so only indirect
> mounts need expire symlinks.
>
> Since the current users of the autofs4 module haven't reproted

s/reproted/reported

- Sedat -

> this as a problem to date this patch probably isn't a candidate
> for backport to stable.
>
> Signed-off-by: Ian Kent <ikent@...hat.com>
> ---
>  fs/autofs4/expire.c  |   14 ++++++++++++++
>  fs/autofs4/symlink.c |    4 ++++
>  2 files changed, 18 insertions(+)
>
> diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
> index 3d9d3f5..394e90b 100644
> --- a/fs/autofs4/expire.c
> +++ b/fs/autofs4/expire.c
> @@ -402,6 +402,20 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
>                         goto next;
>                 }
>
> +               if (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode)) {
> +                       DPRINTK("checking symlink %p %.*s",
> +                               dentry, (int)dentry->d_name.len, dentry->d_name.name);
> +                       /*
> +                        * A symlink can't be "busy" in the usual sense so
> +                        * just check last used for expire timeout.
> +                        */
> +                       if (autofs4_can_expire(dentry, timeout, do_now)) {
> +                               expired = dentry;
> +                               goto found;
> +                       }
> +                       goto next;
> +               }
> +
>                 if (simple_empty(dentry))
>                         goto next;
>
> diff --git a/fs/autofs4/symlink.c b/fs/autofs4/symlink.c
> index f27c094..1e8ea19 100644
> --- a/fs/autofs4/symlink.c
> +++ b/fs/autofs4/symlink.c
> @@ -14,6 +14,10 @@
>
>  static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd)
>  {
> +       struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
> +       struct autofs_info *ino = autofs4_dentry_ino(dentry);
> +       if (ino && !autofs4_oz_mode(sbi))
> +               ino->last_used = jiffies;
>         nd_set_link(nd, dentry->d_inode->i_private);
>         return NULL;
>  }
>
> --
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