>From bf6e48c71803f2c7dfab10196ef43ca1d8f2146f Mon Sep 17 00:00:00 2001
From: Chris Mason <chris.mason@oracle.com>
Date: Tue, 15 Jan 2008 10:05:46 +0100
Subject: [PATCH] ext2: add support for extent_map API

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---
 fs/ext2/ext2.h   |    3 +++
 fs/ext2/ialloc.c |    1 +
 fs/ext2/inode.c  |   15 +++++++++++++++
 fs/ext2/super.c  |    2 ++
 4 files changed, 21 insertions(+), 0 deletions(-)

diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index c87ae29..13c0f77 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -1,5 +1,6 @@
 #include <linux/fs.h>
 #include <linux/ext2_fs.h>
+#include <linux/extent_map.h>
 
 /*
  * ext2 mount options
@@ -62,6 +63,8 @@ struct ext2_inode_info {
 	struct mutex truncate_mutex;
 	struct inode	vfs_inode;
 	struct list_head i_orphan;	/* unlinked but open inodes */
+
+	struct extent_map_tree extent_tree;
 };
 
 /*
diff --git a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
index 5deb8b7..d3fe368 100644
--- a/fs/ext2/ialloc.c
+++ b/fs/ext2/ialloc.c
@@ -584,6 +584,7 @@ got:
 	ei->i_block_alloc_info = NULL;
 	ei->i_block_group = group;
 	ei->i_dir_start_lookup = 0;
+	extent_map_tree_init(&ei->extent_tree);
 	ei->i_state = EXT2_STATE_NEW;
 	ext2_set_inode_flags(inode);
 	spin_lock(&sbi->s_next_gen_lock);
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index b1ab32a..c3555a3 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -31,6 +31,7 @@
 #include <linux/writeback.h>
 #include <linux/buffer_head.h>
 #include <linux/mpage.h>
+#include <linux/extent_map.h>
 #include "ext2.h"
 #include "acl.h"
 #include "xip.h"
@@ -70,9 +71,11 @@ void ext2_delete_inode (struct inode * inode)
 	if (inode->i_blocks)
 		ext2_truncate (inode);
 	ext2_free_inode (inode);
+	remove_extent_mappings(&EXT2_I(inode)->extent_tree, 0, (u64)-1);
 
 	return;
 no_delete:
+	remove_extent_mappings(&EXT2_I(inode)->extent_tree, 0, (u64)-1);
 	clear_inode(inode);	/* We must guarantee clearing of inode... */
 }
 
@@ -709,6 +712,16 @@ int ext2_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_
 
 }
 
+static struct extent_map *ext2_map_extent(struct address_space *mapping,
+					  struct page *page,
+					  size_t page_offset, u64 start,
+					  u64 len, int create, gfp_t gfp_mask)
+{
+	return map_extent_get_block(&EXT2_I(mapping->host)->extent_tree,
+				    mapping, start, len, create, gfp_mask,
+				    ext2_get_block);
+}
+
 static int ext2_writepage(struct page *page, struct writeback_control *wbc)
 {
 	return block_write_full_page(page, ext2_get_block, wbc);
@@ -796,6 +809,7 @@ const struct address_space_operations ext2_aops = {
 	.direct_IO		= ext2_direct_IO,
 	.writepages		= ext2_writepages,
 	.migratepage		= buffer_migrate_page,
+	.map_extent		= ext2_map_extent,
 };
 
 const struct address_space_operations ext2_aops_xip = {
@@ -1242,6 +1256,7 @@ void ext2_read_inode (struct inode * inode)
 	ei->i_state = 0;
 	ei->i_block_group = (ino - 1) / EXT2_INODES_PER_GROUP(inode->i_sb);
 	ei->i_dir_start_lookup = 0;
+	extent_map_tree_init(&ei->extent_tree);
 
 	/*
 	 * NOTE! The in-memory inode i_data array is in little-endian order
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 154e25f..d3bcdc1 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -156,6 +156,7 @@ static struct inode *ext2_alloc_inode(struct super_block *sb)
 
 static void ext2_destroy_inode(struct inode *inode)
 {
+	remove_extent_mappings(&EXT2_I(inode)->extent_tree, 0, (u64)-1);
 	kmem_cache_free(ext2_inode_cachep, EXT2_I(inode));
 }
 
@@ -168,6 +169,7 @@ static void init_once(struct kmem_cache * cachep, void *foo)
 	init_rwsem(&ei->xattr_sem);
 #endif
 	mutex_init(&ei->truncate_mutex);
+	extent_map_tree_init(&ei->extent_tree);
 	inode_init_once(&ei->vfs_inode);
 }
 
-- 
1.5.4.rc2.84.gf85fd