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authorRam Pai <linuxram@us.ibm.com>2005-11-07 17:20:48 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-07 18:18:11 -0800
commita58b0eb8e64b78d9315a5491955e78b1391d42e5 (patch)
tree546f77cb0338c817ef1e34d8ebbc6eaf0e5d6be9 /fs/pnode.c
parenta05964f3917c7c55368c229d7985f8e7c9977e97 (diff)
downloadlinux-linaro-a58b0eb8e64b78d9315a5491955e78b1391d42e5.tar.gz
[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>
Diffstat (limited to 'fs/pnode.c')
-rw-r--r--fs/pnode.c54
1 files changed, 51 insertions, 3 deletions
diff --git a/fs/pnode.c b/fs/pnode.c
index 7bc942d047c..f73eba24f1d 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -17,13 +17,61 @@ static inline struct vfsmount *next_peer(struct vfsmount *p)
return list_entry(p->mnt_share.next, struct vfsmount, mnt_share);
}
+static int do_make_slave(struct vfsmount *mnt)
+{
+ struct vfsmount *peer_mnt = mnt, *master = mnt->mnt_master;
+ struct vfsmount *slave_mnt;
+
+ /*
+ * slave 'mnt' to a peer mount that has the
+ * same root dentry. If none is available than
+ * slave it to anything that is available.
+ */
+ while ((peer_mnt = next_peer(peer_mnt)) != mnt &&
+ peer_mnt->mnt_root != mnt->mnt_root) ;
+
+ if (peer_mnt == mnt) {
+ peer_mnt = next_peer(mnt);
+ if (peer_mnt == mnt)
+ peer_mnt = NULL;
+ }
+ list_del_init(&mnt->mnt_share);
+
+ if (peer_mnt)
+ master = peer_mnt;
+
+ if (master) {
+ list_for_each_entry(slave_mnt, &mnt->mnt_slave_list, mnt_slave)
+ slave_mnt->mnt_master = master;
+ list_del(&mnt->mnt_slave);
+ list_add(&mnt->mnt_slave, &master->mnt_slave_list);
+ list_splice(&mnt->mnt_slave_list, master->mnt_slave_list.prev);
+ INIT_LIST_HEAD(&mnt->mnt_slave_list);
+ } else {
+ struct list_head *p = &mnt->mnt_slave_list;
+ while (!list_empty(p)) {
+ slave_mnt = list_entry(p->next,
+ struct vfsmount, mnt_slave);
+ list_del_init(&slave_mnt->mnt_slave);
+ slave_mnt->mnt_master = NULL;
+ }
+ }
+ mnt->mnt_master = master;
+ CLEAR_MNT_SHARED(mnt);
+ INIT_LIST_HEAD(&mnt->mnt_slave_list);
+ return 0;
+}
+
void change_mnt_propagation(struct vfsmount *mnt, int type)
{
if (type == MS_SHARED) {
set_mnt_shared(mnt);
- } else {
- list_del_init(&mnt->mnt_share);
- mnt->mnt_flags &= ~MNT_PNODE_MASK;
+ return;
+ }
+ do_make_slave(mnt);
+ if (type != MS_SLAVE) {
+ list_del_init(&mnt->mnt_slave);
+ mnt->mnt_master = NULL;
}
}