Commit 48fab5d7 authored Nov 16, 2016 by Amir Goldstein Committed by Miklos Szeredi Dec 16, 2016

ovl: fix nested overlayfs mount



When the upper overlayfs checks "trusted.overlay.*" xattr on the underlying
overlayfs mount, it gets -EPERM, which confuses the upper overlayfs.

Fix this by returning -EOPNOTSUPP instead of -EPERM from
ovl_own_xattr_get() and ovl_own_xattr_set().  This behavior is consistent
with the behavior of ovl_listxattr(), which filters out the private
overlayfs xattrs.

Note: nested overlays are deprecated.  But this change makes sense
regardless: these xattrs are private to the overlay and should always be
hidden.  Hence getting and setting them should indicate this.

[SzMi: Use EOPNOTSUPP instead of ENODATA and use it for both getting and
setting "trusted.overlay." xattrs.  This is a perfectly valid error code
for "we don't support this prefix", which is the case here.]

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

parent 6b2d5fe4

fs/overlayfs/super.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -603,7 +603,7 @@ static int ovl_own_xattr_get(const struct xattr_handler *handler,
		struct dentry dentry, struct inode inode,
		const char name, void buffer, size_t size)
		{
		return -EPERM;
		return -EOPNOTSUPP;
		}

		static int ovl_own_xattr_set(const struct xattr_handler *handler,
		@@ -611,7 +611,7 @@ static int ovl_own_xattr_set(const struct xattr_handler *handler,
		const char name, const void value,
		size_t size, int flags)
		{
		return -EPERM;
		return -EOPNOTSUPP;
		}

		static int ovl_other_xattr_get(const struct xattr_handler *handler,

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