[SCSI] lpfc 8.1.2: Add ERROR and WARM_START modes for diagnostic purposes.

[linux-2.6-omap-h63xx.git] / fs / pnode.c

diff --git a/fs/pnode.c b/fs/pnode.c
index 7bc942d047cd299df0e76282664ba1d052c81c1b..f1871f773f642c8f39045431f5e42134e93ea80f 100644 (file)
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -17,13 +17,73 @@ static inline struct vfsmount *next_peer(struct vfsmount *p)
        return list_entry(p->mnt_share.next, struct vfsmount, mnt_share);
 }
 
+static inline struct vfsmount *first_slave(struct vfsmount *p)
+{
+       return list_entry(p->mnt_slave_list.next, struct vfsmount, mnt_slave);
+}
+
+static inline struct vfsmount *next_slave(struct vfsmount *p)
+{
+       return list_entry(p->mnt_slave.next, struct vfsmount, mnt_slave);
+}
+
+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;
+               if (type == MS_UNBINDABLE)
+                       mnt->mnt_flags |= MNT_UNBINDABLE;
        }
 }
 
@@ -35,10 +95,64 @@ void change_mnt_propagation(struct vfsmount *mnt, int type)
 static struct vfsmount *propagation_next(struct vfsmount *m,
                                         struct vfsmount *origin)
 {
-       m = next_peer(m);
-       if (m == origin)
-               return NULL;
-       return m;
+       /* are there any slaves of this mount? */
+       if (!IS_MNT_NEW(m) && !list_empty(&m->mnt_slave_list))
+               return first_slave(m);
+
+       while (1) {
+               struct vfsmount *next;
+               struct vfsmount *master = m->mnt_master;
+
+               if (master == origin->mnt_master) {
+                       next = next_peer(m);
+                       return ((next == origin) ? NULL : next);
+               } else if (m->mnt_slave.next != &master->mnt_slave_list)
+                       return next_slave(m);
+
+               /* back at master */
+               m = master;
+       }
+}
+
+/*
+ * return the source mount to be used for cloning
+ *
+ * @dest       the current destination mount
+ * @last_dest          the last seen destination mount
+ * @last_src   the last seen source mount
+ * @type       return CL_SLAVE if the new mount has to be
+ *             cloned as a slave.
+ */
+static struct vfsmount *get_source(struct vfsmount *dest,
+                                       struct vfsmount *last_dest,
+                                       struct vfsmount *last_src,
+                                       int *type)
+{
+       struct vfsmount *p_last_src = NULL;
+       struct vfsmount *p_last_dest = NULL;
+       *type = CL_PROPAGATION;;
+
+       if (IS_MNT_SHARED(dest))
+               *type |= CL_MAKE_SHARED;
+
+       while (last_dest != dest->mnt_master) {
+               p_last_dest = last_dest;
+               p_last_src = last_src;
+               last_dest = last_dest->mnt_master;
+               last_src = last_src->mnt_master;
+       }
+
+       if (p_last_dest) {
+               do {
+                       p_last_dest = next_peer(p_last_dest);
+               } while (IS_MNT_NEW(p_last_dest));
+       }
+
+       if (dest != p_last_dest) {
+               *type |= CL_SLAVE;
+               return last_src;
+       } else
+               return p_last_src;
 }
 
 /*
@@ -66,16 +180,15 @@ int propagate_mnt(struct vfsmount *dest_mnt, struct dentry *dest_dentry,
 
        for (m = propagation_next(dest_mnt, dest_mnt); m;
                        m = propagation_next(m, dest_mnt)) {
-               int type = CL_PROPAGATION;
+               int type;
+               struct vfsmount *source;
 
                if (IS_MNT_NEW(m))
                        continue;
 
-               if (IS_MNT_SHARED(m))
-                       type |= CL_MAKE_SHARED;
+               source =  get_source(m, prev_dest_mnt, prev_src_mnt, &type);
 
-               if (!(child = copy_tree(source_mnt, source_mnt->mnt_root,
-                                               type))) {
+               if (!(child = copy_tree(source, source->mnt_root, type))) {
                        ret = -ENOMEM;
                        list_splice(tree_list, tmp_list.prev);
                        goto out;