Btrfs: cache the extent tree preallocation

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

1 files changed, 12 insertions, 2 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index e0738c65bc5b..47e91184fff3 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -741,7 +741,6 @@ static int finish_current_insert(struct btrfs_trans_handle *trans, struct
                 BUG_ON(ret);
         }
         extent_root->fs_info->extent_tree_insert_nr = 0;
-        extent_root->fs_info->extent_tree_prealloc_nr = 0;
         return 0;
 }
 
@@ -951,6 +950,18 @@ static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
                 num_blocks = 1;
                 total_needed = (min(level + 1, BTRFS_MAX_LEVEL) + 2) * 3;
         }
+        if (fill_prealloc) {
+                u64 first;
+                int nr = info->extent_tree_prealloc_nr;
+                first = info->extent_tree_prealloc[nr - 1];
+                if (info->extent_tree_prealloc_nr >= total_needed &&
+                    first >= search_start) {
+                        ins->objectid = info->extent_tree_prealloc[0];
+                        ins->offset = 1;
+                        return 0;
+                }
+                info->extent_tree_prealloc_nr = 0;
+        }
         if (search_end == (u64)-1)
                 search_end = btrfs_super_total_blocks(info->disk_super);
         if (hint_block) {
@@ -1107,7 +1118,6 @@ check_pending:
                 if (ins->objectid + num_blocks > first &&
                     ins->objectid <= info->extent_tree_prealloc[0]) {
                         search_start = info->extent_tree_prealloc[0] + 1;
-                        WARN_ON(!full_scan);
                         goto new_group;
                 }
         }