[ 143/173] vfs: d_obtain_alias() needs to use "/" as default name.

From: Ben Hutchings
Date: Fri Dec 28 2012 - 14:17:45 EST


3.2-stable review patch. If anyone has any objections, please let me know.

------------------

From: NeilBrown <neilb@xxxxxxx>

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@xxxxxxx>
Cc: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
[bwh: Backported to 3.2: use named initialisers instead of QSTR_INIT()]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
fs/dcache.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1492,7 +1492,7 @@ static struct dentry * d_find_any_alias(
*/
struct dentry *d_obtain_alias(struct inode *inode)
{
- static const struct qstr anonstring = { .name = "" };
+ static const struct qstr anonstring = { .name = "/", .len = 1 };
struct dentry *tmp;
struct dentry *res;



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/