[PATCH] ovl: fix wrong WARN_ON() in ovl_cache_update_ino()

[PATCH] ovl: fix wrong WARN_ON() in ovl_cache_update_ino()

[Amir Goldstein]

The WARN_ON() that child entry is always on overlay st_dev became wrong
when we allowed this function to update d_ino in non-samefs setup with
xino enabled.

It is not true in case of xino bits overflow on a non-dir inode.
Leave the WARN_ON() only for directories, where assertion is still true.

Fixes: adbf4f7ea834 ("ovl: consistent d_ino for non-samefs with xino")
Cc: <stable@vger.kernel.org> # v4.17+
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---

Hi Miklos,

Another fall out from testing nested xino setup.

Thanks,
Amir.

 fs/overlayfs/readdir.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 47a91c9733a5..7255e6a5838f 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -504,7 +504,13 @@ static int ovl_cache_update_ino(struct path *path, struct ovl_cache_entry *p)
 		if (err)
 			goto fail;
 
-		WARN_ON_ONCE(dir->d_sb->s_dev != stat.dev);
+		/*
+		 * Directory inode is always on overlay st_dev.
+		 * Non-dir with ovl_same_dev() could be on pseudo st_dev in case
+		 * of xino bits overflow.
+		 */
+		WARN_ON_ONCE(S_ISDIR(stat.mode) &&
+			     dir->d_sb->s_dev != stat.dev);
 		ino = stat.ino;
 	} else if (xinobits && !OVL_TYPE_UPPER(type)) {
 		ino = ovl_remap_lower_ino(ino, xinobits,
-- 
2.17.1

Re: [PATCH] ovl: fix wrong WARN_ON() in ovl_cache_update_ino()

[Amir Goldstein]

On Mon, Dec 23, 2019 at 8:40 AM Amir Goldstein <amir73il@gmail.com> wrote:
>
> The WARN_ON() that child entry is always on overlay st_dev became wrong
> when we allowed this function to update d_ino in non-samefs setup with
> xino enabled.
>
> It is not true in case of xino bits overflow on a non-dir inode.
> Leave the WARN_ON() only for directories, where assertion is still true.
>
> Fixes: adbf4f7ea834 ("ovl: consistent d_ino for non-samefs with xino")
> Cc: <stable@vger.kernel.org> # v4.17+
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
>

Miklos,

If you have time, please send this one to Linus for v5.5.
It is a simple fix and the only one causing failure in the new xfstests [1]
that I posted.

Thanks,
Amir.

[1] https://lore.kernel.org/fstests/20191230141423.31695-1-amir73il@gmail.com/

>
>  fs/overlayfs/readdir.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
> index 47a91c9733a5..7255e6a5838f 100644
> --- a/fs/overlayfs/readdir.c
> +++ b/fs/overlayfs/readdir.c
> @@ -504,7 +504,13 @@ static int ovl_cache_update_ino(struct path *path, struct ovl_cache_entry *p)
>                 if (err)
>                         goto fail;
>
> -               WARN_ON_ONCE(dir->d_sb->s_dev != stat.dev);
> +               /*
> +                * Directory inode is always on overlay st_dev.
> +                * Non-dir with ovl_same_dev() could be on pseudo st_dev in case
> +                * of xino bits overflow.
> +                */
> +               WARN_ON_ONCE(S_ISDIR(stat.mode) &&
> +                            dir->d_sb->s_dev != stat.dev);
>                 ino = stat.ino;
>         } else if (xinobits && !OVL_TYPE_UPPER(type)) {
>                 ino = ovl_remap_lower_ino(ino, xinobits,
> --
> 2.17.1
>

Re: [PATCH] ovl: fix wrong WARN_ON() in ovl_cache_update_ino()

[Amir Goldstein]

On Mon, Jan 6, 2020 at 8:35 AM Amir Goldstein <amir73il@gmail.com> wrote:
>
> On Mon, Dec 23, 2019 at 8:40 AM Amir Goldstein <amir73il@gmail.com> wrote:
> >
> > The WARN_ON() that child entry is always on overlay st_dev became wrong
> > when we allowed this function to update d_ino in non-samefs setup with
> > xino enabled.
> >
> > It is not true in case of xino bits overflow on a non-dir inode.
> > Leave the WARN_ON() only for directories, where assertion is still true.
> >
> > Fixes: adbf4f7ea834 ("ovl: consistent d_ino for non-samefs with xino")
> > Cc: <stable@vger.kernel.org> # v4.17+
> > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > ---
> >
>
> Miklos,
>
> If you have time, please send this one to Linus for v5.5.
> It is a simple fix and the only one causing failure in the new xfstests [1]
> that I posted.
>

Gentle nudge..

Thanks,
Amir.

Re: [PATCH] ovl: fix wrong WARN_ON() in ovl_cache_update_ino()

[Miklos Szeredi]

On Tue, Jan 21, 2020 at 11:04 AM Amir Goldstein <amir73il@gmail.com> wrote:
>
> On Mon, Jan 6, 2020 at 8:35 AM Amir Goldstein <amir73il@gmail.com> wrote:
> >
> > On Mon, Dec 23, 2019 at 8:40 AM Amir Goldstein <amir73il@gmail.com> wrote:
> > >
> > > The WARN_ON() that child entry is always on overlay st_dev became wrong
> > > when we allowed this function to update d_ino in non-samefs setup with
> > > xino enabled.
> > >
> > > It is not true in case of xino bits overflow on a non-dir inode.
> > > Leave the WARN_ON() only for directories, where assertion is still true.
> > >
> > > Fixes: adbf4f7ea834 ("ovl: consistent d_ino for non-samefs with xino")
> > > Cc: <stable@vger.kernel.org> # v4.17+
> > > Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> > > ---
> > >
> >
> > Miklos,
> >
> > If you have time, please send this one to Linus for v5.5.
> > It is a simple fix and the only one causing failure in the new xfstests [1]
> > that I posted.
> >
>
> Gentle nudge..

I'm working this into the next batch bound for 5.6, unless something
more urgent comes up before that.

Thanks,
Miklos

Re: [PATCH] ovl: fix wrong WARN_ON() in ovl_cache_update_ino()

[Amir Goldstein]

> I'm working this into the next batch bound for 5.6, unless something
> more urgent comes up before that.
>

overlayfs-next tested.
ovl-ino rebased.

You would probably want to squash the "merge conflict" below to overlayfs-next.

Thanks,
Amir.


--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1348,7 +1348,7 @@ static int ovl_get_layers(struct super_block
*sb, struct ovl_fs *ofs,
         */
        err = get_anon_bdev(&ofs->fs[0].pseudo_dev);
        if (err) {
-               pr_err("overlayfs: failed to get anonymous bdev for
upper fs\n");
+               pr_err("failed to get anonymous bdev for upper fs\n");
                goto out;
        }

@@ -1409,7 +1409,7 @@ static int ovl_get_layers(struct super_block
*sb, struct ovl_fs *ofs,
         */
        if (ofs->numfs - !ofs->upper_mnt == 1) {
                if (ofs->config.xino == OVL_XINO_ON)
-                       pr_info("overlayfs: \"xino=on\" is useless
with all layers on same fs, ignore.\n");
+                       pr_info("\"xino=on\" is useless with all
layers on same fs, ignore.\n");
                ofs->xino_mode = 0;
        } else if (ofs->config.xino == OVL_XINO_ON && ofs->xino_mode < 0) {