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>

2 files changed, 26 insertions, 44 deletions

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 3eb5a9f30d14..516b90224a1b 100644
--- 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 b02355a7b143..65ef12351566 100644
--- 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);