From: Josef Bacik <jbacik@fusionio.com>
Date: Thu, 2 Aug 2012 14:23:59 +0000 (-0400)
Subject: Btrfs: do not strdup non existent strings
X-Git-Tag: v3.6-rc4~6^2~16
X-Git-Url: http://git.cascardo.info/?a=commitdiff_plain;h=99f5944b8477914406173b47b4f261356286730b;p=cascardo%2Flinux.git

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 b8708f994e67..3b394503bd4e 100644
--- 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;