Patchwork [3.5.y.z,extended,stable] Patch "vfs: d_obtain_alias() needs to use "/" as default" has been added to staging queue

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Submitter Herton Ronaldo Krzesinski
Date Jan. 8, 2013, 8:57 p.m.
Message ID <1357678679-20540-1-git-send-email-herton.krzesinski@canonical.com>
Download mbox | patch
Permalink /patch/210521/
State New
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Comments

Herton Ronaldo Krzesinski - Jan. 8, 2013, 8:57 p.m.
This is a note to let you know that I have just added a patch titled

    vfs: d_obtain_alias() needs to use "/" as default

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

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

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

From 0cc92e888494c489a4f6b91b072718a1f3626216 Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb@suse.de>
Date: Thu, 8 Nov 2012 16:09:37 -0800
Subject: [PATCH 22/27] vfs: d_obtain_alias() needs to use "/" as default
 name.

commit b911a6bdeef5848c468597d040e3407e0aee04ce upstream.

NFS appears to use d_obtain_alias() to create the root dentry rather than
d_make_root.  This can cause 'prepend_path()' to complain that the root
has a weird name if an NFS filesystem is lazily unmounted.  e.g.  if
"/mnt" is an NFS mount then

 { cd /mnt; umount -l /mnt ; ls -l /proc/self/cwd; }

will cause a WARN message like
   WARNING: at /home/git/linux/fs/dcache.c:2624 prepend_path+0x1d7/0x1e0()
   ...
   Root dentry has weird name <>

to appear in kernel logs.

So change d_obtain_alias() to use "/" rather than "" as the anonymous
name.

Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
---
 fs/dcache.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--
1.7.9.5

Patch

diff --git a/fs/dcache.c b/fs/dcache.c
index 9560257..1845c46 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1580,7 +1580,7 @@  EXPORT_SYMBOL(d_find_any_alias);
  */
 struct dentry *d_obtain_alias(struct inode *inode)
 {
-	static const struct qstr anonstring = { .name = "" };
+	static const struct qstr anonstring = QSTR_INIT("/", 1);
 	struct dentry *tmp;
 	struct dentry *res;