From: Miklos Szeredi <mszeredi@xxxxxxx>
Currently getcwd(2) on a detached mount will give a garbled result:
> mkdir /mnt/foo
> mount --bind /etc /mnt/foo
> cd /mnt/foo/skel
> /bin/pwd
/mnt/foo/skel
> umount -l /mnt/foo
> /bin/pwd
etcskel
After the patch it will give a much saner "/skel" result.
Thanks to John Johansen for pointing out this bug.
Reported-by: John Johansen <jjohansen@xxxxxxx>
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
Acked-by: Christoph Hellwig <hch@xxxxxxxxxxxxx>
---
fs/dcache.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
Index: linux-2.6/fs/dcache.c
===================================================================
--- linux-2.6.orig/fs/dcache.c 2008-06-13 13:12:57.000000000 +0200
+++ linux-2.6/fs/dcache.c 2008-06-13 13:13:01.000000000 +0200
@@ -1825,10 +1825,20 @@ char *__d_path(const struct path *path,
return retval;
global_root:
- retval += 1; /* hit the slash */
- name = &dentry->d_name;
- if (prepend(&retval, &buflen, name->name, name->len) != 0)
- goto Elong;
+ /*
+ * If this is a root dentry, then overwrite the slash. This
+ * will also DTRT with pseudo filesystems which have root
+ * dentries named "foo:".
+ *
+ * Otherwise this is the root of a detached mount, so don't do
+ * anything.
+ */
+ if (IS_ROOT(dentry)) {
+ retval += 1;
+ name = &dentry->d_name;
+ if (prepend(&retval, &buflen, name->name, name->len) != 0)
+ goto Elong;
+ }
root->mnt = vfsmnt;
root->dentry = dentry;
return retval;
--
--
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