On Sun, Sep 04, 2016 at 01:37:36AM +0200, ziegler@xxxxxxxxxxxxxxx wrote:
> Dear Miklos,
>
> overlayfs works still in v4.8-rc4, but not longer in the newest kernel:
>
>
> If the four directories test_lowerdir,test/upperd, test/workd,
> test_mountdir exist, the command
>
> mount -t overlay -o lowerdir=test_lowerdir,upperdir=test/upperd,workdir=test/workd,noatime overlay test_mountdir
>
> does not produce a writable files system. The kernel says:
>
>
> kernel: overlayfs: failed to create directory /root/test/workd/work (errno: 95); mounting read-only
>
>
> I bisected between v4.8-rc4 and v4.8-rc4-359-g4b30b6d and found
>
> c11b9fdd6a612f376a5e886505f1c54c16d8c380
> Author: Miklos Szeredi <mszeredi@xxxxxxxxxx>
> Date: Thu Sep 1 11:11:59 2016 +0200
>
> ovl: remove posix_acl_default from workdir
>
> responsible. Reverting this makes overlayfs work again.
>
Thanks for spotting this bug!
The following patch should fix it. Pushed to overlayfs-linus branch of
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git
Thanks,
Miklos
---
From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Subject: ovl: fix workdir creation
Workdir creation fails in latest kernel.
Fix by allowing EOPNOTSUPP as a valid return value from
vfs_removexattr(XATTR_NAME_POSIX_ACL_*). Upper filesystem may not support
ACL and still be perfectly able to support overlayfs.
Reported-by: Martin Ziegler <ziegler@xxxxxxxxxxxxxxx>
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Fixes: c11b9fdd6a61 ("ovl: remove posix_acl_default from workdir")
Cc: <stable@xxxxxxxxxxxxxxx>
---
fs/overlayfs/super.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -835,11 +835,11 @@ static struct dentry *ovl_workdir_create
goto out_dput;
err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_DEFAULT);
- if (err && err != -ENODATA)
+ if (err && err != -ENODATA && err != -EOPNOTSUPP)
goto out_dput;
err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_ACCESS);
- if (err && err != -ENODATA)
+ if (err && err != -ENODATA && err != -EOPNOTSUPP)
goto out_dput;
/* Clear any inherited mode bits */
--
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