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-rw-r--r--fs/namespace.c31
1 files changed, 31 insertions, 0 deletions
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?
*/