From 7e4745a09426b3fe63e9fbea3190e0f8500820a4 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Tue, 5 Jul 2022 12:22:46 -0400 Subject: [PATCH] switch try_to_unlazy_next() to __legitimize_mnt() The tricky case (__legitimize_mnt() failing after having grabbed a reference) can be trivially dealt with by leaving nd->path.mnt non-NULL, for terminate_walk() to drop it. legitimize_mnt() becomes static after that. Signed-off-by: Al Viro --- fs/mount.h | 1 - fs/namei.c | 9 +++++++-- fs/namespace.c | 2 +- 3 files changed, 8 insertions(+), 4 deletions(-) diff --git a/fs/mount.h b/fs/mount.h index 0b6e08cf8afb..130c07c2f8d2 100644 --- a/fs/mount.h +++ b/fs/mount.h @@ -100,7 +100,6 @@ static inline int is_mounted(struct vfsmount *mnt) extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *); extern int __legitimize_mnt(struct vfsmount *, unsigned); -extern bool legitimize_mnt(struct vfsmount *, unsigned); static inline bool __path_is_mountpoint(const struct path *path) { diff --git a/fs/namei.c b/fs/namei.c index 9c50facb9769..e864d5b9eeac 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -799,13 +799,18 @@ out: */ static bool try_to_unlazy_next(struct nameidata *nd, struct dentry *dentry, unsigned seq) { + int res; BUG_ON(!(nd->flags & LOOKUP_RCU)); nd->flags &= ~LOOKUP_RCU; if (unlikely(!legitimize_links(nd))) goto out2; - if (unlikely(!legitimize_mnt(nd->path.mnt, nd->m_seq))) - goto out2; + res = __legitimize_mnt(nd->path.mnt, nd->m_seq); + if (unlikely(res)) { + if (res > 0) + goto out2; + goto out1; + } if (unlikely(!lockref_get_not_dead(&nd->path.dentry->d_lockref))) goto out1; diff --git a/fs/namespace.c b/fs/namespace.c index e6a7e769d25d..68789f896f08 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -648,7 +648,7 @@ int __legitimize_mnt(struct vfsmount *bastard, unsigned seq) } /* call under rcu_read_lock */ -bool legitimize_mnt(struct vfsmount *bastard, unsigned seq) +static bool legitimize_mnt(struct vfsmount *bastard, unsigned seq) { int res = __legitimize_mnt(bastard, seq); if (likely(!res))