diff options
| -rw-r--r-- | fs/namespace.c | 36 |
1 files changed, 24 insertions, 12 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 54847db5b819..1686b4442f1d 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1767,6 +1767,19 @@ bool may_mount(void) return ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN); } +/** + * path_mounted - check whether path is mounted + * @path: path to check + * + * Determine whether @path refers to the root of a mount. + * + * Return: true if @path is the root of a mount, false if not. + */ +static inline bool path_mounted(const struct path *path) +{ + return path->mnt->mnt_root == path->dentry; +} + static void warn_mandlock(void) { pr_warn_once("=======================================================\n" @@ -1782,7 +1795,7 @@ static int can_umount(const struct path *path, int flags) if (!may_mount()) return -EPERM; - if (path->dentry != path->mnt->mnt_root) + if (!path_mounted(path)) return -EINVAL; if (!check_mnt(mnt)) return -EINVAL; @@ -2367,7 +2380,7 @@ static int do_change_type(struct path *path, int ms_flags) int type; int err = 0; - if (path->dentry != path->mnt->mnt_root) + if (!path_mounted(path)) return -EINVAL; type = flags_to_propagation_type(ms_flags); @@ -2643,7 +2656,7 @@ static int do_reconfigure_mnt(struct path *path, unsigned int mnt_flags) if (!check_mnt(mnt)) return -EINVAL; - if (path->dentry != mnt->mnt.mnt_root) + if (!path_mounted(path)) return -EINVAL; if (!can_change_locked_flags(mnt, mnt_flags)) @@ -2682,7 +2695,7 @@ static int do_remount(struct path *path, int ms_flags, int sb_flags, if (!check_mnt(mnt)) return -EINVAL; - if (path->dentry != path->mnt->mnt_root) + if (!path_mounted(path)) return -EINVAL; if (!can_change_locked_flags(mnt, mnt_flags)) @@ -2772,9 +2785,9 @@ static int do_set_group(struct path *from_path, struct path *to_path) err = -EINVAL; /* To and From paths should be mount roots */ - if (from_path->dentry != from_path->mnt->mnt_root) + if (!path_mounted(from_path)) goto out; - if (to_path->dentry != to_path->mnt->mnt_root) + if (!path_mounted(to_path)) goto out; /* Setting sharing groups is only allowed across same superblock */ @@ -2855,7 +2868,7 @@ static int do_move_mount(struct path *old_path, struct path *new_path) if (old->mnt.mnt_flags & MNT_LOCKED) goto out; - if (old_path->dentry != old_path->mnt->mnt_root) + if (!path_mounted(old_path)) goto out; if (d_is_dir(new_path->dentry) != @@ -2937,8 +2950,7 @@ static int do_add_mount(struct mount *newmnt, struct mountpoint *mp, } /* Refuse the same filesystem on the same mount point */ - if (path->mnt->mnt_sb == newmnt->mnt.mnt_sb && - path->mnt->mnt_root == path->dentry) + if (path->mnt->mnt_sb == newmnt->mnt.mnt_sb && path_mounted(path)) return -EBUSY; if (d_is_symlink(newmnt->mnt.mnt_root)) @@ -3917,11 +3929,11 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, if (new_mnt == root_mnt || old_mnt == root_mnt) goto out4; /* loop, on the same file system */ error = -EINVAL; - if (root.mnt->mnt_root != root.dentry) + if (!path_mounted(&root)) goto out4; /* not a mountpoint */ if (!mnt_has_parent(root_mnt)) goto out4; /* not attached */ - if (new.mnt->mnt_root != new.dentry) + if (!path_mounted(&new)) goto out4; /* not a mountpoint */ if (!mnt_has_parent(new_mnt)) goto out4; /* not attached */ @@ -4124,7 +4136,7 @@ static int do_mount_setattr(struct path *path, struct mount_kattr *kattr) struct mount *mnt = real_mount(path->mnt); int err = 0; - if (path->dentry != mnt->mnt.mnt_root) + if (!path_mounted(path)) return -EINVAL; if (kattr->mnt_userns) { |