Btrfs: Defrag only leaves, and only when the parent node has a single objectid

This allows us to defrag huge directories, but skip the expensive defrag
case in more common usage, where it does not help as much.

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

1 files changed, 16 insertions, 6 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 984f4745440e..74fec6b83a8b 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -16,6 +16,7 @@
  * Boston, MA 021110-1307, USA.
  */
 
+#include <linux/sched.h>
 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"
@@ -190,7 +191,8 @@ static int should_defrag_leaf(struct extent_buffer *leaf)
 
 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root, struct extent_buffer *parent,
-                       int cache_only, u64 *last_ret)
+                       int start_slot, int cache_only, u64 *last_ret,
+                       struct btrfs_key *progress)
 {
         struct extent_buffer *cur;
         struct extent_buffer *tmp;
@@ -199,7 +201,6 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
         u64 last_block = 0;
         u64 other;
         u32 parent_nritems;
-        int start_slot;
         int end_slot;
         int i;
         int err = 0;
@@ -221,15 +222,24 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
 
         parent_nritems = btrfs_header_nritems(parent);
         blocksize = btrfs_level_size(root, parent_level - 1);
-
-        start_slot = 0;
         end_slot = parent_nritems;
 
         if (parent_nritems == 1)
                 return 0;
 
+        if (root != root->fs_info->extent_root) {
+                struct btrfs_key first_key;
+                struct btrfs_key last_key;
+
+                btrfs_node_key_to_cpu(parent, &first_key, 0);
+                btrfs_node_key_to_cpu(parent, &last_key, parent_nritems - 1);
+                if (first_key.objectid != last_key.objectid)
+                        return 0;
+        }
+
         for (i = start_slot; i < end_slot; i++) {
                 int close = 1;
+
                 blocknr = btrfs_node_blockptr(parent, i);
                 if (last_block == 0)
                         last_block = blocknr;
@@ -898,7 +908,7 @@ static void reada_for_search(struct btrfs_root *root, struct btrfs_path *path,
         u32 blocksize;
         u32 nscan = 0;
 
-        if (level == 0)
+        if (level != 1)
                 return;
 
         if (!path->nodes[level])
@@ -2370,7 +2380,7 @@ int btrfs_del_item(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                 }
 
                 /* delete the leaf if it is mostly empty */
-                if (used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
+                if (0 && used < BTRFS_LEAF_DATA_SIZE(root) / 3) {
                         /* push_leaf_left fixes the path.
                          * make sure the path still points to our leaf
                          * for possible call to del_ptr below