From: Vivek Goyal <vgoyal@redhat.com>
To: Miklos Szeredi <mszeredi@redhat.com>
Cc: linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 4/4] ovl: alllow remote upper
Date: Tue, 4 Feb 2020 09:59:51 -0500 [thread overview]
Message-ID: <20200204145951.GC11631@redhat.com> (raw)
In-Reply-To: <20200131115004.17410-5-mszeredi@redhat.com>
On Fri, Jan 31, 2020 at 12:50:04PM +0100, Miklos Szeredi wrote:
> No reason to prevent upper layer being a remote filesystem. Do the
> revalidation in that case, just as we already do for lower layers.
>
> This lets virtiofs be used as upper layer, which appears to be a real use
> case.
Hi Miklos,
I have couple of very basic questions.
- So with this change, we will allow NFS to be upper layer also?
- What does revalidation on lower/upper mean? Does that mean that
lower/upper can now change underneath overlayfs and overlayfs will
cope with it. If we still expect underlying layers not to change, then
what's the point of calling ->revalidate().
Thanks
Vivek
>
> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
> ---
> fs/overlayfs/namei.c | 3 +--
> fs/overlayfs/super.c | 8 ++++++--
> fs/overlayfs/util.c | 2 ++
> 3 files changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
> index 76e61cc27822..0db23baf98e7 100644
> --- a/fs/overlayfs/namei.c
> +++ b/fs/overlayfs/namei.c
> @@ -845,8 +845,7 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
> if (err)
> goto out;
>
> - if (upperdentry && (upperdentry->d_flags & DCACHE_OP_REAL ||
> - unlikely(ovl_dentry_remote(upperdentry)))) {
> + if (upperdentry && upperdentry->d_flags & DCACHE_OP_REAL) {
> dput(upperdentry);
> err = -EREMOTE;
> goto out;
> diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
> index 26d4153240a8..ed3a11db9039 100644
> --- a/fs/overlayfs/super.c
> +++ b/fs/overlayfs/super.c
> @@ -135,9 +135,14 @@ static int ovl_dentry_revalidate_common(struct dentry *dentry,
> unsigned int flags, bool weak)
> {
> struct ovl_entry *oe = dentry->d_fsdata;
> + struct dentry *upper;
> unsigned int i;
> int ret = 1;
>
> + upper = ovl_dentry_upper(dentry);
> + if (upper)
> + ret = ovl_revalidate_real(upper, flags, weak);
> +
> for (i = 0; ret > 0 && i < oe->numlower; i++) {
> ret = ovl_revalidate_real(oe->lowerstack[i].dentry, flags,
> weak);
> @@ -747,8 +752,7 @@ static int ovl_mount_dir(const char *name, struct path *path)
> ovl_unescape(tmp);
> err = ovl_mount_dir_noesc(tmp, path);
>
> - if (!err && (ovl_dentry_remote(path->dentry) ||
> - path->dentry->d_flags & DCACHE_OP_REAL)) {
> + if (!err && path->dentry->d_flags & DCACHE_OP_REAL) {
> pr_err("filesystem on '%s' not supported as upperdir\n",
> tmp);
> path_put_init(path);
> diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
> index 3ad8fb291f7d..c793722739e1 100644
> --- a/fs/overlayfs/util.c
> +++ b/fs/overlayfs/util.c
> @@ -96,6 +96,8 @@ void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *upperdentry,
> struct ovl_entry *oe = OVL_E(dentry);
> unsigned int i, flags = 0;
>
> + if (upperdentry)
> + flags |= upperdentry->d_flags;
> for (i = 0; i < oe->numlower; i++)
> flags |= oe->lowerstack[i].dentry->d_flags;
>
> --
> 2.21.1
>
next prev parent reply other threads:[~2020-02-04 14:59 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-31 11:50 [PATCH 0/4] ovl: allow virtiofs as upper Miklos Szeredi
2020-01-31 11:50 ` [PATCH 1/4] ovl: restructure dentry revalidation Miklos Szeredi
2020-01-31 11:50 ` [PATCH 2/4] ovl: separate detection of remote upper layer from stacked overlay Miklos Szeredi
2020-01-31 11:50 ` [PATCH 3/4] ovl: decide if revalidate needed on a per-dentry bases Miklos Szeredi
2020-01-31 14:53 ` Amir Goldstein
2020-01-31 15:15 ` Miklos Szeredi
2020-01-31 11:50 ` [PATCH 4/4] ovl: alllow remote upper Miklos Szeredi
2020-01-31 15:29 ` Amir Goldstein
2020-01-31 15:38 ` Miklos Szeredi
2020-01-31 15:50 ` Amir Goldstein
2020-01-31 16:05 ` Miklos Szeredi
2020-02-04 14:59 ` Vivek Goyal [this message]
2020-02-04 16:16 ` Miklos Szeredi
2020-02-04 17:02 ` Amir Goldstein
2020-02-04 18:42 ` Vivek Goyal
2020-02-04 19:11 ` Amir Goldstein
2020-02-04 19:16 ` Miklos Szeredi
2020-02-20 7:52 ` Amir Goldstein
2020-02-20 20:00 ` Amir Goldstein
2020-03-14 13:16 ` Amir Goldstein
2020-03-16 17:54 ` Vivek Goyal
2020-03-16 19:02 ` Amir Goldstein
2020-03-16 19:40 ` Vivek Goyal
2020-03-18 13:36 ` unionmount testsuite with upper virtiofs Amir Goldstein
2020-03-19 21:40 ` Vivek Goyal
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