Btrfs: Add run time btree defrag, and an ioctl to force btree defrag

This adds two types of btree defrag, a run time form that tries to
defrag recently allocated blocks in the btree when they are still in ram,
and an ioctl that forces defrag of all btree blocks.

File data blocks are not defragged yet, but this can make a huge difference
in sequential btree reads.

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

1 files changed, 17 insertions, 2 deletions

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index c5a18d5d7f7c..42aa20301bc9 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -178,6 +178,7 @@ struct btrfs_path {
         struct buffer_head *nodes[BTRFS_MAX_LEVEL];
         int slots[BTRFS_MAX_LEVEL];
         int reada;
+        int lowest_level;
 };
 
 /*
@@ -338,6 +339,9 @@ struct btrfs_root {
         u64 highest_inode;
         u64 last_inode_alloc;
         int ref_cows;
+        struct btrfs_key defrag_progress;
+        int defrag_running;
+        int defrag_level;
 };
 
 /* the lower bits in the key flags defines the item type */
@@ -1031,10 +1035,11 @@ struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
 int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root);
 struct buffer_head *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
-                                            struct btrfs_root *root, u64 hint);
+                                            struct btrfs_root *root, u64 hint,
+                                            u64 empty_size);
 int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root, u64 owner,
-                       u64 num_blocks, u64 search_start,
+                       u64 num_blocks, u64 empty_size, u64 search_start,
                        u64 search_end, struct btrfs_key *ins, int data);
 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
                   struct buffer_head *buf);
@@ -1051,6 +1056,10 @@ int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
 int btrfs_free_block_groups(struct btrfs_fs_info *info);
 int btrfs_read_block_groups(struct btrfs_root *root);
 /* ctree.c */
+int btrfs_cow_block(struct btrfs_trans_handle *trans, struct btrfs_root
+                           *root, struct buffer_head *buf, struct buffer_head
+                           *parent, int parent_slot, struct buffer_head
+                           **cow_ret);
 int btrfs_extend_item(struct btrfs_trans_handle *trans, struct btrfs_root
                       *root, struct btrfs_path *path, u32 data_size);
 int btrfs_truncate_item(struct btrfs_trans_handle *trans,
@@ -1060,6 +1069,9 @@ int btrfs_truncate_item(struct btrfs_trans_handle *trans,
 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
                       *root, struct btrfs_key *key, struct btrfs_path *p, int
                       ins_len, int cow);
+int btrfs_realloc_node(struct btrfs_trans_handle *trans,
+                       struct btrfs_root *root, struct buffer_head *parent,
+                       int cache_only);
 void btrfs_release_path(struct btrfs_root *root, struct btrfs_path *p);
 struct btrfs_path *btrfs_alloc_path(void);
 void btrfs_free_path(struct btrfs_path *p);
@@ -1171,4 +1183,7 @@ extern struct file_operations btrfs_file_operations;
 int btrfs_drop_extents(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root, struct inode *inode,
                        u64 start, u64 end, u64 *hint_block);
+/* tree-defrag.c */
+int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
+                        struct btrfs_root *root, int cache_only);
 #endif