diff options
| -rw-r--r-- | fs/mount.h | 1 | ||||
| -rw-r--r-- | fs/namespace.c | 27 |
2 files changed, 20 insertions, 8 deletions
diff --git a/fs/mount.h b/fs/mount.h index 6a61c2b3e385..b5b8082bfa42 100644 --- a/fs/mount.h +++ b/fs/mount.h @@ -88,6 +88,7 @@ static inline int is_mounted(struct vfsmount *mnt) extern struct mount *__lookup_mnt(struct vfsmount *, struct dentry *); extern struct mount *__lookup_mnt_last(struct vfsmount *, struct dentry *); +extern int __legitimize_mnt(struct vfsmount *, unsigned); extern bool legitimize_mnt(struct vfsmount *, unsigned); extern void __detach_mounts(struct dentry *dentry); diff --git a/fs/namespace.c b/fs/namespace.c index 1b9e11167bae..9c1c43d0d4f1 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -590,24 +590,35 @@ static void delayed_free_vfsmnt(struct rcu_head *head) } /* call under rcu_read_lock */ -bool legitimize_mnt(struct vfsmount *bastard, unsigned seq) +int __legitimize_mnt(struct vfsmount *bastard, unsigned seq) { struct mount *mnt; if (read_seqretry(&mount_lock, seq)) - return false; + return 1; if (bastard == NULL) - return true; + return 0; mnt = real_mount(bastard); mnt_add_count(mnt, 1); if (likely(!read_seqretry(&mount_lock, seq))) - return true; + return 0; if (bastard->mnt_flags & MNT_SYNC_UMOUNT) { mnt_add_count(mnt, -1); - return false; + return 1; + } + return -1; +} + +/* call under rcu_read_lock */ +bool legitimize_mnt(struct vfsmount *bastard, unsigned seq) +{ + int res = __legitimize_mnt(bastard, seq); + if (likely(!res)) + return true; + if (unlikely(res < 0)) { + rcu_read_unlock(); + mntput(bastard); + rcu_read_lock(); } - rcu_read_unlock(); - mntput(bastard); - rcu_read_lock(); return false; } |