Btrfs: Create larger bios for btree blocks

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

fs/btrfs/disk-io.c

@@ -197,7 +197,8 @@ int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 		WARN_ON(1);
 	}
 	eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
-	read_extent_buffer_pages(tree, eb, start + PAGE_CACHE_SIZE, 1);
+	read_extent_buffer_pages(tree, eb, start + PAGE_CACHE_SIZE, 1,
+				 btree_get_extent);
 	btrfs_clear_buffer_defrag(eb);
 	found_start = btrfs_header_bytenr(eb);
 	if (found_start != start) {
@@ -339,7 +340,7 @@ int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize)
 	if (!buf)
 		return 0;
 	read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
-				 buf, 0, 0);
+				 buf, 0, 0, btree_get_extent);
 	free_extent_buffer(buf);
 	return ret;
 }
@@ -358,7 +359,8 @@ struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 	buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 	if (!buf)
 		return NULL;
-	read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree, buf, 0, 1);
+	read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree, buf, 0, 1,
+				 btree_get_extent);
 
 	if (buf->flags & EXTENT_CSUM)
 		return buf;
@@ -1009,7 +1011,7 @@ int btrfs_read_buffer(struct extent_buffer *buf)
 	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)->io_tree,
-					buf, 0, 1);
+					buf, 0, 1, btree_get_extent);
 }
 
 static struct extent_io_ops btree_extent_io_ops = {

fs/btrfs/extent_io.c

@@ -2859,8 +2859,8 @@ EXPORT_SYMBOL(extent_buffer_uptodate);
 
 int read_extent_buffer_pages(struct extent_io_tree *tree,
 			     struct extent_buffer *eb,
-			     u64 start,
-			     int wait)
+			     u64 start, int wait,
+			     get_extent_t *get_extent)
 {
 	unsigned long i;
 	unsigned long start_i;
@@ -2868,6 +2868,8 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 	int err;
 	int ret = 0;
 	unsigned long num_pages;
+	struct bio *bio = NULL;
+
 
 	if (eb->flags & EXTENT_UPTODATE)
 		return 0;
@@ -2899,7 +2901,8 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 			lock_page(page);
 		}
 		if (!PageUptodate(page)) {
-			err = page->mapping->a_ops->readpage(NULL, page);
+			err = __extent_read_full_page(tree, page,
+						      get_extent, &bio);
 			if (err) {
 				ret = err;
 			}
@@ -2908,6 +2911,9 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
 		}
 	}
 
+	if (bio)
+		submit_one_bio(READ, bio);
+
 	if (ret || !wait) {
 		return ret;
 	}

fs/btrfs/extent_io.h

@@ -157,7 +157,8 @@ struct extent_buffer *find_extent_buffer(struct extent_io_tree *tree,
 					  gfp_t mask);
 void free_extent_buffer(struct extent_buffer *eb);
 int read_extent_buffer_pages(struct extent_io_tree *tree,
-			     struct extent_buffer *eb, u64 start, int wait);
+			     struct extent_buffer *eb, u64 start, int wait,
+			     get_extent_t *get_extent);
 
 static inline void extent_buffer_get(struct extent_buffer *eb)
 {