linux-kernel - [PATCH 5.16 09/43] ovl: dont fail copy up if no fileattr support on upper

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Date:   Fri,  4 Feb 2022 10:22:16 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Christoph Fritz <chf.fritz@...glemail.com>,
        Miklos Szeredi <mszeredi@...hat.com>
Subject: [PATCH 5.16 09/43] ovl: dont fail copy up if no fileattr support on upper

From: Miklos Szeredi <mszeredi@...hat.com>

commit 94fd19752b28aa66c98e7991734af91dfc529f8f upstream.

Christoph Fritz is reporting that failure to copy up fileattr when upper
doesn't support fileattr or xattr results in a regression.

Return success in these failure cases; this reverts overlayfs to the old
behavior.

Add a pr_warn_once() in these cases to still let the user know about the
copy up failures.

Reported-by: Christoph Fritz <chf.fritz@...glemail.com>
Fixes: 72db82115d2b ("ovl: copy up sync/noatime fileattr flags")
Cc: <stable@...r.kernel.org> # v5.15
Signed-off-by: Miklos Szeredi <mszeredi@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/overlayfs/copy_up.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -157,7 +157,9 @@ static int ovl_copy_fileattr(struct inod
 	 */
 	if (oldfa.flags & OVL_PROT_FS_FLAGS_MASK) {
 		err = ovl_set_protattr(inode, new->dentry, &oldfa);
-		if (err)
+		if (err == -EPERM)
+			pr_warn_once("copying fileattr: no xattr on upper\n");
+		else if (err)
 			return err;
 	}
 
@@ -167,6 +169,14 @@ static int ovl_copy_fileattr(struct inod
 
 	err = ovl_real_fileattr_get(new, &newfa);
 	if (err) {
+		/*
+		 * Returning an error if upper doesn't support fileattr will
+		 * result in a regression, so revert to the old behavior.
+		 */
+		if (err == -ENOTTY || err == -EINVAL) {
+			pr_warn_once("copying fileattr: no support on upper\n");
+			return 0;
+		}
 		pr_warn("failed to retrieve upper fileattr (%pd2, err=%i)\n",
 			new, err);
 		return err;