Btrfs: remove last_log_alloc allocator optimization

The tree logging code was trying to separate tree log allocations
from normal metadata allocations to improve writeback patterns during
an fsync.

But, the code was not effective and ended up just mixing tree log
blocks with regular metadata.  That seems to be working fairly well,
so the last_log_alloc code can be removed.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 0 insertions, 7 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index db37b867e4f..29380467b67 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2228,13 +2228,6 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans,
         if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD))
                 last_ptr = &root->fs_info->last_data_alloc;
 
-        if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
-                last_ptr = &root->fs_info->last_log_alloc;
-                if (!last_ptr == 0 && root->fs_info->last_alloc) {
-                        *last_ptr = root->fs_info->last_alloc + empty_cluster;
-                }
-        }
-
         if (last_ptr) {
                 if (*last_ptr)
                         hint_byte = *last_ptr;