Btrfs: Split the extent_map code into two parts

There is now extent_map for mapping offsets in the file to disk and
extent_io for state tracking, IO submission and extent_bufers.

The new extent_map code shifts from [start,end] pairs to [start,len], and
pushes the locking out into the caller.  This allows a few performance
optimizations and is easier to use.

A number of extent_map usage bugs were fixed, mostly with failing
to remove extent_map entries when changing the file.

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

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h
index 9fc99883c70a..9a0647dc5a0b 100644
--- a/fs/btrfs/btrfs_inode.h
+++ b/fs/btrfs/btrfs_inode.h
@@ -20,6 +20,7 @@
 #define __BTRFS_I__
 
 #include "extent_map.h"
+#include "extent_io.h"
 
 /* in memory btrfs inode */
 struct btrfs_inode {
@@ -27,6 +28,7 @@ struct btrfs_inode {
         struct btrfs_block_group_cache *block_group;
         struct btrfs_key location;
         struct extent_map_tree extent_tree;
+        struct extent_io_tree io_tree;
         struct inode vfs_inode;
 
         u64 ordered_trans;