66 lines
2.2 KiB
Diff
66 lines
2.2 KiB
Diff
From c0ea161a6e7158281f64bc6d41126da43cb08f14 Mon Sep 17 00:00:00 2001
|
|
From: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Date: Sat, 15 Aug 2015 13:36:12 -0500
|
|
Subject: [PATCH 1/2] dcache: Handle escaped paths in prepend_path
|
|
|
|
commit cde93be45a8a90d8c264c776fab63487b5038a65 upstream.
|
|
|
|
A rename can result in a dentry that by walking up d_parent
|
|
will never reach it's mnt_root. For lack of a better term
|
|
I call this an escaped path.
|
|
|
|
prepend_path is called by four different functions __d_path,
|
|
d_absolute_path, d_path, and getcwd.
|
|
|
|
__d_path only wants to see paths are connected to the root it passes
|
|
in. So __d_path needs prepend_path to return an error.
|
|
|
|
d_absolute_path similarly wants to see paths that are connected to
|
|
some root. Escaped paths are not connected to any mnt_root so
|
|
d_absolute_path needs prepend_path to return an error greater
|
|
than 1. So escaped paths will be treated like paths on lazily
|
|
unmounted mounts.
|
|
|
|
getcwd needs to prepend "(unreachable)" so getcwd also needs
|
|
prepend_path to return an error.
|
|
|
|
d_path is the interesting hold out. d_path just wants to print
|
|
something, and does not care about the weird cases. Which raises
|
|
the question what should be printed?
|
|
|
|
Given that <escaped_path>/<anything> should result in -ENOENT I
|
|
believe it is desirable for escaped paths to be printed as empty
|
|
paths. As there are not really any meaninful path components when
|
|
considered from the perspective of a mount tree.
|
|
|
|
So tweak prepend_path to return an empty path with an new error
|
|
code of 3 when it encounters an escaped path.
|
|
|
|
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
---
|
|
fs/dcache.c | 7 +++++++
|
|
1 file changed, 7 insertions(+)
|
|
|
|
diff --git a/fs/dcache.c b/fs/dcache.c
|
|
index 9b5fe503f6cb..e3b44ca75a1b 100644
|
|
--- a/fs/dcache.c
|
|
+++ b/fs/dcache.c
|
|
@@ -2926,6 +2926,13 @@ restart:
|
|
|
|
if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) {
|
|
struct mount *parent = ACCESS_ONCE(mnt->mnt_parent);
|
|
+ /* Escaped? */
|
|
+ if (dentry != vfsmnt->mnt_root) {
|
|
+ bptr = *buffer;
|
|
+ blen = *buflen;
|
|
+ error = 3;
|
|
+ break;
|
|
+ }
|
|
/* Global root? */
|
|
if (mnt != parent) {
|
|
dentry = ACCESS_ONCE(mnt->mnt_mountpoint);
|
|
--
|
|
2.4.3
|
|
|