diff options
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index c1ac585e41e3..843bc6191f30 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -2714,6 +2714,10 @@ static int do_change_type(struct path *path, int ms_flags) return -EINVAL; namespace_lock(); + if (!check_mnt(mnt)) { + err = -EINVAL; + goto out_unlock; + } if (type == MS_SHARED) { err = invent_group_ids(mnt, recurse); if (err) @@ -3151,7 +3155,7 @@ static int do_set_group(struct path *from_path, struct path *to_path) if (IS_MNT_SLAVE(from)) { struct mount *m = from->mnt_master; - list_add(&to->mnt_slave, &m->mnt_slave_list); + list_add(&to->mnt_slave, &from->mnt_slave); to->mnt_master = m; } @@ -3176,18 +3180,25 @@ out: * Check if path is overmounted, i.e., if there's a mount on top of * @path->mnt with @path->dentry as mountpoint. * - * Context: This function expects namespace_lock() to be held. + * Context: namespace_sem must be held at least shared. + * MUST NOT be called under lock_mount_hash() (there one should just + * call __lookup_mnt() and check if it returns NULL). * Return: If path is overmounted true is returned, false if not. */ static inline bool path_overmounted(const struct path *path) { + unsigned seq = read_seqbegin(&mount_lock); + bool no_child; + rcu_read_lock(); - if (unlikely(__lookup_mnt(path->mnt, path->dentry))) { - rcu_read_unlock(); - return true; - } + no_child = !__lookup_mnt(path->mnt, path->dentry); rcu_read_unlock(); - return false; + if (need_seqretry(&mount_lock, seq)) { + read_seqlock_excl(&mount_lock); + no_child = !__lookup_mnt(path->mnt, path->dentry); + read_sequnlock_excl(&mount_lock); + } + return unlikely(!no_child); } /** |