Btrfs: do not strdup non existent strings

When we close devices we add back empty devices for some reason that escapes
me.  In the case of a missing dev we don't allocate an rcu_string for it's
name, so check to see if the device has a name and if it doesn't don't
bother strdup()'ing it.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>

diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index b8708f9..3b39450 100644 (file)
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -569,9 +569,11 @@ static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
                memcpy(new_device, device, sizeof(*new_device));
 
                /* Safe because we are under uuid_mutex */
-               name = rcu_string_strdup(device->name->str, GFP_NOFS);
-               BUG_ON(device->name && !name); /* -ENOMEM */
-               rcu_assign_pointer(new_device->name, name);
+               if (device->name) {
+                       name = rcu_string_strdup(device->name->str, GFP_NOFS);
+                       BUG_ON(device->name && !name); /* -ENOMEM */
+                       rcu_assign_pointer(new_device->name, name);
+               }
                new_device->bdev = NULL;
                new_device->writeable = 0;
                new_device->in_fs_metadata = 0;