Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dledford/rdma

[linux-2.6-block.git] / fs / namespace.c

diff --git a/fs/namespace.c b/fs/namespace.c
index c7cb8a526c05fbaa5ba18934cd04eda1eb2a6e60..2b8aa15fd6dfa755368ddf21136eaab5192f1e28 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1361,6 +1361,36 @@ enum umount_tree_flags {
        UMOUNT_PROPAGATE = 2,
        UMOUNT_CONNECTED = 4,
 };
+
+static bool disconnect_mount(struct mount *mnt, enum umount_tree_flags how)
+{
+       /* Leaving mounts connected is only valid for lazy umounts */
+       if (how & UMOUNT_SYNC)
+               return true;
+
+       /* A mount without a parent has nothing to be connected to */
+       if (!mnt_has_parent(mnt))
+               return true;
+
+       /* Because the reference counting rules change when mounts are
+        * unmounted and connected, umounted mounts may not be
+        * connected to mounted mounts.
+        */
+       if (!(mnt->mnt_parent->mnt.mnt_flags & MNT_UMOUNT))
+               return true;
+
+       /* Has it been requested that the mount remain connected? */
+       if (how & UMOUNT_CONNECTED)
+               return false;
+
+       /* Is the mount locked such that it needs to remain connected? */
+       if (IS_MNT_LOCKED(mnt))
+               return false;
+
+       /* By default disconnect the mount */
+       return true;
+}
+
 /*
  * mount_lock must be held
  * namespace_sem must be held for write
@@ -1398,10 +1428,7 @@ static void umount_tree(struct mount *mnt, enum umount_tree_flags how)
                if (how & UMOUNT_SYNC)
                        p->mnt.mnt_flags |= MNT_SYNC_UMOUNT;
 
-               disconnect = !(((how & UMOUNT_CONNECTED) &&
-                               mnt_has_parent(p) &&
-                               (p->mnt_parent->mnt.mnt_flags & MNT_UMOUNT)) ||
-                              IS_MNT_LOCKED_AND_LAZY(p));
+               disconnect = disconnect_mount(p, how);
 
                pin_insert_group(&p->mnt_umount, &p->mnt_parent->mnt,
                                 disconnect ? &unmounted : NULL);
@@ -1538,11 +1565,8 @@ void __detach_mounts(struct dentry *dentry)
        while (!hlist_empty(&mp->m_list)) {
                mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list);
                if (mnt->mnt.mnt_flags & MNT_UMOUNT) {
-                       struct mount *p, *tmp;
-                       list_for_each_entry_safe(p, tmp, &mnt->mnt_mounts,  mnt_child) {
-                               hlist_add_head(&p->mnt_umount.s_list, &unmounted);
-                               umount_mnt(p);
-                       }
+                       hlist_add_head(&mnt->mnt_umount.s_list, &unmounted);
+                       umount_mnt(mnt);
                }
                else umount_tree(mnt, UMOUNT_CONNECTED);
        }