[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>

2 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8bdb504be73b..eef66f54c017 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -105,6 +105,7 @@ extern int dir_notify_enable;
 #define MS_REC          16384
 #define MS_VERBOSE      32768
 #define MS_PRIVATE      (1<<18) /* change to private */
+#define MS_SLAVE        (1<<19) /* change to slave */
 #define MS_SHARED       (1<<20) /* change to shared */
 #define MS_POSIXACL     (1<<16) /* VFS does not apply the umask */
 #define MS_ACTIVE       (1<<30)
diff --git a/include/linux/mount.h b/include/linux/mount.h
index 2582559718fc..7e133ae2a94f 100644
--- a/include/linux/mount.h
+++ b/include/linux/mount.h
@@ -38,6 +38,9 @@ struct vfsmount {
         struct list_head mnt_list;
         struct list_head mnt_expire;    /* link in fs-specific expiry list */
         struct list_head mnt_share;     /* circular list of shared mounts */
+        struct list_head mnt_slave_list;/* list of slave mounts */
+        struct list_head mnt_slave;     /* slave list entry */
+        struct vfsmount *mnt_master;    /* slave is on master->mnt_slave_list */
         struct namespace *mnt_namespace; /* containing namespace */
         int mnt_pinned;
 };