commit 810191ff3087e8143b41a944fcf4fd8c693f00e3
author Chris Mason <chris.mason@oracle.com> Mon Oct 15 16:18:55 2007 -0400
committer Chris Mason <chris.mason@oracle.com> Thu Sep 25 11:03:56 2008 -0400
tree 9d23dd51458623eaac41bc8c89dd2998a2eda7ae
parent 3326d1b07c0cb6a2ff5b835b7a2cffa54124d074

Btrfs: extent_map optimizations to cut down on CPU usage

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

fs/btrfs/disk-io.c

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index fd7e6c1..16f0260 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -644,20 +644,20 @@
 
 int btrfs_buffer_uptodate(struct extent_buffer *buf)
 {
-	struct inode *btree_inode = buf->last_page->mapping->host;
+	struct inode *btree_inode = buf->first_page->mapping->host;
 	return extent_buffer_uptodate(&BTRFS_I(btree_inode)->extent_tree, buf);
 }
 
 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
 {
-	struct inode *btree_inode = buf->last_page->mapping->host;
+	struct inode *btree_inode = buf->first_page->mapping->host;
 	return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->extent_tree,
 					  buf);
 }
 
 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
 {
-	struct btrfs_root *root = BTRFS_I(buf->last_page->mapping->host)->root;
+	struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
 	u64 transid = btrfs_header_generation(buf);
 	struct inode *btree_inode = root->fs_info->btree_inode;
 
@@ -678,7 +678,7 @@
 
 void btrfs_set_buffer_defrag(struct extent_buffer *buf)
 {
-	struct btrfs_root *root = BTRFS_I(buf->last_page->mapping->host)->root;
+	struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
 	struct inode *btree_inode = root->fs_info->btree_inode;
 	set_extent_bits(&BTRFS_I(btree_inode)->extent_tree, buf->start,
 			buf->start + buf->len - 1, EXTENT_DEFRAG, GFP_NOFS);
@@ -686,7 +686,7 @@
 
 void btrfs_set_buffer_defrag_done(struct extent_buffer *buf)
 {
-	struct btrfs_root *root = BTRFS_I(buf->last_page->mapping->host)->root;
+	struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
 	struct inode *btree_inode = root->fs_info->btree_inode;
 	set_extent_bits(&BTRFS_I(btree_inode)->extent_tree, buf->start,
 			buf->start + buf->len - 1, EXTENT_DEFRAG_DONE,
@@ -695,7 +695,7 @@
 
 int btrfs_buffer_defrag(struct extent_buffer *buf)
 {
-	struct btrfs_root *root = BTRFS_I(buf->last_page->mapping->host)->root;
+	struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
 	struct inode *btree_inode = root->fs_info->btree_inode;
 	return test_range_bit(&BTRFS_I(btree_inode)->extent_tree,
 		     buf->start, buf->start + buf->len - 1, EXTENT_DEFRAG, 0);
@@ -703,7 +703,7 @@
 
 int btrfs_buffer_defrag_done(struct extent_buffer *buf)
 {
-	struct btrfs_root *root = BTRFS_I(buf->last_page->mapping->host)->root;
+	struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
 	struct inode *btree_inode = root->fs_info->btree_inode;
 	return test_range_bit(&BTRFS_I(btree_inode)->extent_tree,
 		     buf->start, buf->start + buf->len - 1,
@@ -712,7 +712,7 @@
 
 int btrfs_clear_buffer_defrag_done(struct extent_buffer *buf)
 {
-	struct btrfs_root *root = BTRFS_I(buf->last_page->mapping->host)->root;
+	struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
 	struct inode *btree_inode = root->fs_info->btree_inode;
 	return clear_extent_bits(&BTRFS_I(btree_inode)->extent_tree,
 		     buf->start, buf->start + buf->len - 1,
@@ -721,7 +721,7 @@
 
 int btrfs_clear_buffer_defrag(struct extent_buffer *buf)
 {
-	struct btrfs_root *root = BTRFS_I(buf->last_page->mapping->host)->root;
+	struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
 	struct inode *btree_inode = root->fs_info->btree_inode;
 	return clear_extent_bits(&BTRFS_I(btree_inode)->extent_tree,
 		     buf->start, buf->start + buf->len - 1,
@@ -730,7 +730,7 @@
 
 int btrfs_read_buffer(struct extent_buffer *buf)
 {
-	struct btrfs_root *root = BTRFS_I(buf->last_page->mapping->host)->root;
+	struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
 	struct inode *btree_inode = root->fs_info->btree_inode;
 	return read_extent_buffer_pages(&BTRFS_I(btree_inode)->extent_tree,
 					buf, 1);