[PATCH] introduce slave mounts

A slave mount always has a master mount from which it receives
mount/umount events.  Unlike shared mount the event propagation does not
flow from the slave mount to the master.

Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/fs/namespace.c b/fs/namespace.c
index 4b1af01c2fb4..46f99bc585bd 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -67,6 +67,8 @@ struct vfsmount *alloc_vfsmnt(const char *name)
                 INIT_LIST_HEAD(&mnt->mnt_list);
                 INIT_LIST_HEAD(&mnt->mnt_expire);
                 INIT_LIST_HEAD(&mnt->mnt_share);
+                INIT_LIST_HEAD(&mnt->mnt_slave_list);
+                INIT_LIST_HEAD(&mnt->mnt_slave);
                 if (name) {
                         int size = strlen(name) + 1;
                         char *newname = kmalloc(size, GFP_KERNEL);
@@ -1243,7 +1245,7 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
                                     data_page);
         else if (flags & MS_BIND)
                 retval = do_loopback(&nd, dev_name, flags & MS_REC);
-        else if (flags & (MS_SHARED | MS_PRIVATE))
+        else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE))
                 retval = do_change_type(&nd, flags);
         else if (flags & MS_MOVE)
                 retval = do_move_mount(&nd, dev_name);