From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
[ Upstream commit eacd9aa8cedeb412842c7b339adbaa0477fdd5ad ]
After switching to non-RCU mode, we want nd->depth to match the number
of entries in nd->stack[] that need eventual path_put().
legitimize_links() takes care of that on failures; unfortunately,
failure exits added for LOOKUP_CACHED do not.
We could add the logics for that into those failure exits, both in
try_to_unlazy() and in try_to_unlazy_next(), but since both checks
are immediately followed by legitimize_links() and there's no calls
of legitimize_links() other than those two... It's easier to
move the check (and required handling of nd->depth on failure) into
legitimize_links() itself.
[caught by Jens: ... and since we are zeroing ->depth here, we need
to do drop_links() first]
Fixes: 6c6ec2b0a3e0 "fs: add support for LOOKUP_CACHED"
Tested-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/namei.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -630,6 +630,11 @@ static inline bool legitimize_path(struc
static bool legitimize_links(struct nameidata *nd)
{
int i;
+ if (unlikely(nd->flags & LOOKUP_CACHED)) {
+ drop_links(nd);
+ nd->depth = 0;
+ return false;
+ }
for (i = 0; i < nd->depth; i++) {
struct saved *last = nd->stack + i;
if (unlikely(!legitimize_path(nd, &last->link, last->seq))) {
@@ -686,8 +691,6 @@ static bool try_to_unlazy(struct nameida
BUG_ON(!(nd->flags & LOOKUP_RCU));
nd->flags &= ~LOOKUP_RCU;
- if (nd->flags & LOOKUP_CACHED)
- goto out1;
if (unlikely(!legitimize_links(nd)))
goto out1;
if (unlikely(!legitimize_path(nd, &nd->path, nd->seq)))
@@ -724,8 +727,6 @@ static bool try_to_unlazy_next(struct na
BUG_ON(!(nd->flags & LOOKUP_RCU));
nd->flags &= ~LOOKUP_RCU;
- if (nd->flags & LOOKUP_CACHED)
- goto out2;
if (unlikely(!legitimize_links(nd)))
goto out2;
if (unlikely(!legitimize_mnt(nd->path.mnt, nd->m_seq)))
