diff options
| -rw-r--r-- | fs/mount.h | 9 | ||||
| -rw-r--r-- | fs/namespace.c | 31 |
2 files changed, 40 insertions, 0 deletions
diff --git a/fs/mount.h b/fs/mount.h index 68bb03ed7f19..f82c62840905 100644 --- a/fs/mount.h +++ b/fs/mount.h @@ -87,6 +87,15 @@ extern struct mount *__lookup_mnt_last(struct vfsmount *, struct dentry *); extern bool legitimize_mnt(struct vfsmount *, unsigned); +extern void __detach_mounts(struct dentry *dentry); + +static inline void detach_mounts(struct dentry *dentry) +{ + if (!d_mountpoint(dentry)) + return; + __detach_mounts(dentry); +} + static inline void get_mnt_ns(struct mnt_namespace *ns) { atomic_inc(&ns->count); diff --git a/fs/namespace.c b/fs/namespace.c index 88fc3f4d77ed..00e5b1efa591 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1468,6 +1468,37 @@ static int do_umount(struct mount *mnt, int flags) return retval; } +/* + * __detach_mounts - lazily unmount all mounts on the specified dentry + * + * During unlink, rmdir, and d_drop it is possible to loose the path + * to an existing mountpoint, and wind up leaking the mount. + * detach_mounts allows lazily unmounting those mounts instead of + * leaking them. + * + * The caller may hold dentry->d_inode->i_mutex. + */ +void __detach_mounts(struct dentry *dentry) +{ + struct mountpoint *mp; + struct mount *mnt; + + namespace_lock(); + mp = lookup_mountpoint(dentry); + if (!mp) + goto out_unlock; + + lock_mount_hash(); + while (!hlist_empty(&mp->m_list)) { + mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list); + umount_tree(mnt, 2); + } + unlock_mount_hash(); + put_mountpoint(mp); +out_unlock: + namespace_unlock(); +} + /* * Is the caller allowed to modify his namespace? */ |