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, 1 deletions

diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile
index 72cc3e16741f..9c61609f3714 100644
--- a/fs/btrfs/Makefile
+++ b/fs/btrfs/Makefile
@@ -5,7 +5,8 @@ obj-m  := btrfs.o
 btrfs-y := super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \
            hash.o file-item.o inode-item.o inode-map.o disk-io.o \
            transaction.o bit-radix.o inode.o file.o tree-defrag.o \
-           extent_map.o sysfs.o struct-funcs.o xattr.o ordered-data.o
+           extent_map.o sysfs.o struct-funcs.o xattr.o ordered-data.o \
+           extent_io.o
 
 ifeq ($(CONFIG_FS_POSIX_ACL),y)
 btrfs-y += acl.o