Btrfs: kill BTRFS_I(inode)->block_group

Originally this was going to be used as a way to give hints to the allocator,
but frankly we can get much better hints elsewhere and it's not even used at all
for anything usefull.  In addition to be completely useless, when we initialize
an inode we try and find a freeish block group to set as the inodes block group,
and with a completely full 40gb fs this takes _forever_, so I imagine with say
1tb fs this is just unbearable.  So just axe the thing altoghether, we don't
need it and it saves us 8 bytes in the inode and saves us 500 microseconds per
inode lookup in my testcase.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>

1 files changed, 0 insertions, 2 deletions

diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
index cfd660550ded..72ab0295ca74 100644
--- a/fs/btrfs/xattr.c
+++ b/fs/btrfs/xattr.c
@@ -158,8 +158,6 @@ int __btrfs_setxattr(struct btrfs_trans_handle *trans,
         if (IS_ERR(trans))
                 return PTR_ERR(trans);
 
-        btrfs_set_trans_block_group(trans, inode);
-
         ret = do_setxattr(trans, inode, name, value, size, flags);
         if (ret)
                 goto out;