From: Al Viro viro@zeniv.linux.org.uk
[ 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@kernel.dk Signed-off-by: Al Viro viro@zeniv.linux.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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)))