Btrfs: Tune the automatic defrag code

1) Forced defrag wasn't working properly (btrfsctl -d) because some
cache only checks were incorrect.

2) Defrag only the leaves unless in forced defrag mode.

3) Don't use complex logic to figure out if a leaf is needs defrag

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

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 3eb5a9f30d14e6f9d4f33ead23a724cc250d362a..516b90224a1b7951245fbd03df2fc99127b07258 100644 (file)
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -161,34 +161,6 @@ static int close_blocks(u64 blocknr, u64 other, u32 blocksize)
        return 0;
 }
 
-static int should_defrag_leaf(struct extent_buffer *leaf)
-{
-       struct btrfs_key key;
-       u32 nritems;
-
-       if (btrfs_buffer_defrag(leaf))
-               return 1;
-
-       nritems = btrfs_header_nritems(leaf);
-       if (nritems == 0)
-               return 0;
-
-       btrfs_item_key_to_cpu(leaf, &key, 0);
-       if (key.type == BTRFS_DIR_ITEM_KEY)
-               return 1;
-
-
-       btrfs_item_key_to_cpu(leaf, &key, nritems - 1);
-       if (key.type == BTRFS_DIR_ITEM_KEY)
-               return 1;
-       if (nritems > 4) {
-               btrfs_item_key_to_cpu(leaf, &key, nritems / 2);
-               if (key.type == BTRFS_DIR_ITEM_KEY)
-                       return 1;
-       }
-       return 0;
-}
-
 int btrfs_realloc_node(struct btrfs_trans_handle *trans,
                       struct btrfs_root *root, struct extent_buffer *parent,
                       int start_slot, int cache_only, u64 *last_ret,
@@ -208,6 +180,10 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
        int uptodate;
        u32 blocksize;
 
+       parent_level = btrfs_header_level(parent);
+       if (cache_only && parent_level != 1)
+               return 0;
+
        if (trans->transaction != root->fs_info->running_transaction) {
                printk(KERN_CRIT "trans %Lu running %Lu\n", trans->transid,
                       root->fs_info->running_transaction->transid);
@@ -218,7 +194,6 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
                       root->fs_info->generation);
                WARN_ON(1);
        }
-       parent_level = btrfs_header_level(parent);
 
        parent_nritems = btrfs_header_nritems(parent);
        blocksize = btrfs_level_size(root, parent_level - 1);
@@ -227,27 +202,26 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
        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;
 
+               if (!parent->map_token) {
+                       map_extent_buffer(parent,
+                                       btrfs_node_key_ptr_offset(i),
+                                       sizeof(struct btrfs_key_ptr),
+                                       &parent->map_token, &parent->kaddr,
+                                       &parent->map_start, &parent->map_len,
+                                       KM_USER1);
+               }
                blocknr = btrfs_node_blockptr(parent, i);
                if (last_block == 0)
                        last_block = blocknr;
+
                if (i > 0) {
                        other = btrfs_node_blockptr(parent, i - 1);
                        close = close_blocks(blocknr, other, blocksize);
                }
-               if (close && i < end_slot - 1) {
+               if (close && i < end_slot - 2) {
                        other = btrfs_node_blockptr(parent, i + 1);
                        close = close_blocks(blocknr, other, blocksize);
                }
@@ -255,15 +229,18 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
                        last_block = blocknr;
                        continue;
                }
+               if (parent->map_token) {
+                       unmap_extent_buffer(parent, parent->map_token,
+                                           KM_USER1);
+                       parent->map_token = NULL;
+               }
 
                cur = btrfs_find_tree_block(root, blocknr, blocksize);
                if (cur)
                        uptodate = btrfs_buffer_uptodate(cur);
                else
                        uptodate = 0;
-               if (!cur || !uptodate ||
-                   (parent_level != 1 && !btrfs_buffer_defrag(cur)) ||
-                   (parent_level == 1 && !should_defrag_leaf(cur))) {
+               if (!cur || !uptodate) {
                        if (cache_only) {
                                free_extent_buffer(cur);
                                continue;
@@ -287,11 +264,17 @@ int btrfs_realloc_node(struct btrfs_trans_handle *trans,
                        break;
                }
                search_start = tmp->start;
+               last_block = tmp->start;
                *last_ret = search_start;
                if (parent_level == 1)
                        btrfs_clear_buffer_defrag(tmp);
                free_extent_buffer(tmp);
        }
+       if (parent->map_token) {
+               unmap_extent_buffer(parent, parent->map_token,
+                                   KM_USER1);
+               parent->map_token = NULL;
+       }
        return err;
 }
 

diff --git a/fs/btrfs/tree-defrag.c b/fs/btrfs/tree-defrag.c
index b02355a7b143e4ce82ef5f73b70ed2695430fd3b..65ef12351566e23a1b124998251bca016dcf5ec2 100644 (file)
--- a/fs/btrfs/tree-defrag.c
+++ b/fs/btrfs/tree-defrag.c
@@ -183,7 +183,6 @@ int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
        if (level == 0) {
                goto out;
        }
-
        if (root->defrag_progress.objectid == 0) {
                extent_buffer_get(root->node);
                ret = btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);