[3.16.y-ckt stable] Patch "vfs: Remove incorrect debugging WARN in prepend_path" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    vfs: Remove incorrect debugging WARN in prepend_path

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt15.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 217860733c15eb55b45fd943d07f2fb94300712c Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm at xmission.com>
Date: Sun, 24 May 2015 09:25:00 -0500
Subject: vfs: Remove incorrect debugging WARN in prepend_path

commit 93e3bce6287e1fb3e60d3324ed08555b5bbafa89 upstream.

The warning message in prepend_path is unclear and outdated.  It was
added as a warning that the mechanism for generating names of pseudo
files had been removed from prepend_path and d_dname should be used
instead.  Unfortunately the warning reads like a general warning,
making it unclear what to do with it.

Remove the warning.  The transition it was added to warn about is long
over, and I added code several years ago which in rare cases causes
the warning to fire on legitimate code, and the warning is now firing
and scaring people for no good reason.

Reported-by: Ivan Delalande <colona at arista.com>
Reported-by: Omar Sandoval <osandov at osandov.com>
Fixes: f48cfddc6729e ("vfs: In d_path don't call d_dname on a mount point")
Signed-off-by: "Eric W. Biederman" <ebiederm at xmission.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/dcache.c | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index 05a041a134c4..df0de6b95409 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2898,17 +2898,6 @@ restart:
 				vfsmnt = &mnt->mnt;
 				continue;
 			}
-			/*
-			 * Filesystems needing to implement special "root names"
-			 * should do so with ->d_dname()
-			 */
-			if (IS_ROOT(dentry) &&
-			   (dentry->d_name.len != 1 ||
-			    dentry->d_name.name[0] != '/')) {
-				WARN(1, "Root dentry has weird name <%.*s>\n",
-				     (int) dentry->d_name.len,
-				     dentry->d_name.name);
-			}
 			if (!error)
 				error = is_mounted(vfsmnt) ? 1 : 2;
 			break;