Patch "ovl: warn instead of error if d_type is not supported" has been added to the 4.6-stable tree

Patch "ovl: warn instead of error if d_type is not supported" has been added to the 4.6-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ovl: warn instead of error if d_type is not supported

to the 4.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ovl-warn-instead-of-error-if-d_type-is-not-supported.patch
and it can be found in the queue-4.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From e7c0b5991dd1be7b6f6dc2b54a15a0f47b64b007 Mon Sep 17 00:00:00 2001
From: Vivek Goyal <vgoyal@redhat.com>
Date: Fri, 1 Jul 2016 10:02:44 -0400
Subject: ovl: warn instead of error if d_type is not supported

From: Vivek Goyal <vgoyal@redhat.com>

commit e7c0b5991dd1be7b6f6dc2b54a15a0f47b64b007 upstream.

overlay needs underlying fs to support d_type. Recently I put in a
patch in to detect this condition and started failing mount if
underlying fs did not support d_type.

But this breaks existing configurations over kernel upgrade. Those who
are running docker (partially broken configuration) with xfs not
supporting d_type, are surprised that after kernel upgrade docker does
not run anymore.

https://github.com/docker/docker/issues/22937#issuecomment-229881315

So instead of erroring out, detect broken configuration and warn
about it. This should allow existing docker setups to continue
working after kernel upgrade.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: 45aebeaf4f67 ("ovl: Ensure upper filesystem supports d_type")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/overlayfs/super.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1072,11 +1072,13 @@ static int ovl_fill_super(struct super_b
 			if (err < 0)
 				goto out_put_workdir;
 
-			if (!err) {
-				pr_err("overlayfs: upper fs needs to support d_type.\n");
-				err = -EINVAL;
-				goto out_put_workdir;
-			}
+			/*
+			 * We allowed this configuration and don't want to
+			 * break users over kernel upgrade. So warn instead
+			 * of erroring out.
+			 */
+			if (!err)
+				pr_warn("overlayfs: upper fs needs to support d_type.\n");
 		}
 	}
 


Patches currently in stable-queue which might be from vgoyal@redhat.com are

queue-4.6/ovl-warn-instead-of-error-if-d_type-is-not-supported.patch
queue-4.6/ovl-copy-up-underlying-inode-s-i_mode-to-overlay-inode.patch
queue-4.6/ovl-do-d_type-check-only-if-work-dir-creation-was-successful.patch