From: Ian Kent <raven@themaw.net>
To: "McIntyre, Vincent (CASS, Marsfield)" <Vincent.Mcintyre@csiro.au>
Cc: Al Viro <viro@ZenIV.linux.org.uk>,
autofs mailing list <autofs@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 4/4] autofs: add comment about autofs_mountpoint_changed()
Date: Fri, 27 Mar 2020 19:33:17 +0800 [thread overview]
Message-ID: <11a106b080f743964c86e6c0dd3ce32aa5d48b1b.camel@themaw.net> (raw)
In-Reply-To: <20200327051928.i5xtvskvktbugifa@mayhem.atnf.CSIRO.AU>
On Fri, 2020-03-27 at 05:19 +0000, McIntyre, Vincent (CASS, Marsfield)
wrote:
> One nit, below.
Yeah, thanks for that, you effort looking at the patches is
appreciated, I'll fix it.
> Vince
>
> On Thu, Mar 26, 2020 at 01:23:36PM +0800, Ian Kent wrote:
> > The function autofs_mountpoint_changed() is unusual, add a comment
> > about two cases for which it is used.
> >
> > Signed-off-by: Ian Kent <raven@themaw.net>
> > ---
> > fs/autofs/root.c | 21 ++++++++++++++++++---
> > 1 file changed, 18 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/autofs/root.c b/fs/autofs/root.c
> > index 308cc49aca1d..a972bbaecb46 100644
> > --- a/fs/autofs/root.c
> > +++ b/fs/autofs/root.c
> > @@ -280,9 +280,24 @@ static struct dentry
> > *autofs_mountpoint_changed(struct path *path)
> > struct dentry *dentry = path->dentry;
> > struct autofs_sb_info *sbi = autofs_sbi(dentry->d_sb);
> >
> > - /*
> > - * If this is an indirect mount the dentry could have gone away
> > - * as a result of an expire and a new one created.
> > + /* If this is an indirect mount the dentry could have gone away
> > + * and a new one created.
> > + *
> > + * This is unusual and I can't remember the case for which it
> > + * was originally added now. But a example of how this can
>
> 'an' example
>
> > + * happen is an autofs indirect mount that has the "browse"
> > + * option set and also has the "symlink" option in the autofs
> > + * map entry. In this case the daemon will remove the browse
> > + * directory and create a symlink as the mount (pointing to a
> > + * local path) leaving the struct path stale.
> > + *
> > + * Another not so obvious case is when a mount in an autofs
> > + * indirect mount that uses the "nobrowse" option is being
> > + * expired and the mount has been umounted but the mount point
> > + * directory remains when a stat family system call is made.
> > + * In this case the mount point is removed (by the daemon) and
> > + * a new mount triggered leading to a stale dentry in the
> > struct
> > + * path of the waiting process.
> > */
> > if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) {
> > struct dentry *parent = dentry->d_parent;
> >
>
> --
next prev parent reply other threads:[~2020-03-27 11:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-26 5:23 [PATCH 1/4] autofs: dont call do_expire_wait() in autofs_d_manage() Ian Kent
2020-03-26 5:23 ` [PATCH 2/4] autofs: remove rcu_walk parameter from autofs_expire_wait() Ian Kent
2020-03-26 5:23 ` [PATCH 3/4] vfs: check for autofs expiring dentry in follow_automount() Ian Kent
2020-03-27 5:18 ` McIntyre, Vincent (CASS, Marsfield)
2020-03-27 11:31 ` Ian Kent
2020-03-26 5:23 ` [PATCH 4/4] autofs: add comment about autofs_mountpoint_changed() Ian Kent
2020-03-27 5:19 ` McIntyre, Vincent (CASS, Marsfield)
2020-03-27 11:33 ` Ian Kent [this message]
2020-03-30 23:06 [PATCH 1/4] autofs: dont call do_expire_wait() in autofs_d_manage() Ian Kent
2020-03-30 23:07 ` [PATCH 4/4] autofs: add comment about autofs_mountpoint_changed() Ian Kent
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