mnt: Delay removal from the mount hash.
- Modify __lookup_mnt_hash_last to ignore mounts that have MNT_UMOUNTED set.
- Don't remove mounts from the mount hash table in propogate_umount
- Don't remove mounts from the mount hash table in umount_tree before
the entire list of mounts to be umounted is selected.
- Remove mounts from the mount hash table as the last thing that
happens in the case where a mount has a parent in umount_tree.
Mounts without parents are not hashed (by definition).
This paves the way for delaying removal from the mount hash table even
farther and fixing the MNT_LOCKED vs MNT_DETACH issue.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/fs/namespace.c b/fs/namespace.c
index d170814..083e340 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -632,14 +632,17 @@
*/
struct mount *__lookup_mnt_last(struct vfsmount *mnt, struct dentry *dentry)
{
- struct mount *p, *res;
- res = p = __lookup_mnt(mnt, dentry);
+ struct mount *p, *res = NULL;
+ p = __lookup_mnt(mnt, dentry);
if (!p)
goto out;
+ if (!(p->mnt.mnt_flags & MNT_UMOUNT))
+ res = p;
hlist_for_each_entry_continue(p, mnt_hash) {
if (&p->mnt_parent->mnt != mnt || p->mnt_mountpoint != dentry)
break;
- res = p;
+ if (!(p->mnt.mnt_flags & MNT_UMOUNT))
+ res = p;
}
out:
return res;
@@ -1336,9 +1339,8 @@
list_move(&p->mnt_list, &tmp_list);
}
- /* Hide the mounts from lookup_mnt and mnt_mounts */
+ /* Hide the mounts from mnt_mounts */
list_for_each_entry(p, &tmp_list, mnt_list) {
- hlist_del_init_rcu(&p->mnt_hash);
list_del_init(&p->mnt_child);
}
@@ -1365,6 +1367,7 @@
p->mnt_mountpoint = p->mnt.mnt_root;
p->mnt_parent = p;
p->mnt_mp = NULL;
+ hlist_del_init_rcu(&p->mnt_hash);
}
change_mnt_propagation(p, MS_PRIVATE);
}