From: Badari Pulavarty <pbadari@us.ibm.com>

Pass amount of disk needs to be mapped to get_block().  This way one can
modify the fs ->get_block() functions to map multiple blocks at the same time.

Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 fs/buffer.c                 |    6 ++++++
 fs/mpage.c                  |    2 ++
 include/linux/buffer_head.h |    1 +
 3 files changed, 9 insertions(+)

diff -puN fs/buffer.c~pass-b_size-to-get_block fs/buffer.c
--- devel/fs/buffer.c~pass-b_size-to-get_block	2006-03-11 02:47:08.000000000 -0800
+++ devel-akpm/fs/buffer.c	2006-03-11 02:47:08.000000000 -0800
@@ -1782,6 +1782,7 @@ static int __block_write_full_page(struc
 			clear_buffer_dirty(bh);
 			set_buffer_uptodate(bh);
 		} else if (!buffer_mapped(bh) && buffer_dirty(bh)) {
+			bh->b_size = 1 << inode->i_blkbits;
 			err = get_block(inode, block, bh, 1);
 			if (err)
 				goto recover;
@@ -1935,6 +1936,7 @@ static int __block_prepare_write(struct 
 		if (buffer_new(bh))
 			clear_buffer_new(bh);
 		if (!buffer_mapped(bh)) {
+			bh->b_size = 1 << inode->i_blkbits;
 			err = get_block(inode, block, bh, 1);
 			if (err)
 				break;
@@ -2090,6 +2092,7 @@ int block_read_full_page(struct page *pa
 
 			fully_mapped = 0;
 			if (iblock < lblock) {
+				bh->b_size = 1 << inode->i_blkbits;
 				err = get_block(inode, iblock, bh, 0);
 				if (err)
 					SetPageError(page);
@@ -2411,6 +2414,7 @@ int nobh_prepare_write(struct page *page
 		create = 1;
 		if (block_start >= to)
 			create = 0;
+		map_bh.b_size = 1 << blkbits;
 		ret = get_block(inode, block_in_file + block_in_page,
 					&map_bh, create);
 		if (ret)
@@ -2671,6 +2675,7 @@ int block_truncate_page(struct address_s
 
 	err = 0;
 	if (!buffer_mapped(bh)) {
+		bh->b_size = 1 << inode->i_blkbits;
 		err = get_block(inode, iblock, bh, 0);
 		if (err)
 			goto unlock;
@@ -2757,6 +2762,7 @@ sector_t generic_block_bmap(struct addre
 	struct inode *inode = mapping->host;
 	tmp.b_state = 0;
 	tmp.b_blocknr = 0;
+	tmp.b_size = 1 << inode->i_blkbits;
 	get_block(inode, block, &tmp, 0);
 	return tmp.b_blocknr;
 }
diff -puN fs/mpage.c~pass-b_size-to-get_block fs/mpage.c
--- devel/fs/mpage.c~pass-b_size-to-get_block	2006-03-11 02:47:08.000000000 -0800
+++ devel-akpm/fs/mpage.c	2006-03-11 02:47:08.000000000 -0800
@@ -192,6 +192,7 @@ do_mpage_readpage(struct bio *bio, struc
 				page_block++, block_in_file++) {
 		bh.b_state = 0;
 		if (block_in_file < last_block) {
+			bh.b_size = blocksize;
 			if (get_block(inode, block_in_file, &bh, 0))
 				goto confused;
 		}
@@ -472,6 +473,7 @@ __mpage_writepage(struct bio *bio, struc
 	for (page_block = 0; page_block < blocks_per_page; ) {
 
 		map_bh.b_state = 0;
+		map_bh.b_size = 1 << blkbits;
 		if (get_block(inode, block_in_file, &map_bh, 1))
 			goto confused;
 		if (buffer_new(&map_bh))
diff -puN include/linux/buffer_head.h~pass-b_size-to-get_block include/linux/buffer_head.h
--- devel/include/linux/buffer_head.h~pass-b_size-to-get_block	2006-03-11 02:47:08.000000000 -0800
+++ devel-akpm/include/linux/buffer_head.h	2006-03-11 02:47:08.000000000 -0800
@@ -280,6 +280,7 @@ map_bh(struct buffer_head *bh, struct su
 	set_buffer_mapped(bh);
 	bh->b_bdev = sb->s_bdev;
 	bh->b_blocknr = block;
+	bh->b_size =  sb->s_blocksize;
 }
 
 /*
_