jfs: stop using the nobh helper

The nobh mode is an obscure feature to save lowlevel for large memory
32-bit configurations while trading for much slower performance and
has been long obsolete.  Switch to the regular buffer head based helpers
instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

fs/jfs/inode.c

@@ -301,13 +301,25 @@ static int jfs_write_begin(struct file *file, struct address_space *mapping,
 {
 	int ret;
 
-	ret = nobh_write_begin(mapping, pos, len, pagep, fsdata, jfs_get_block);
+	ret = block_write_begin(mapping, pos, len, pagep, jfs_get_block);
 	if (unlikely(ret))
 		jfs_write_failed(mapping, pos + len);
 
 	return ret;
 }
 
+static int jfs_write_end(struct file *file, struct address_space *mapping,
+		loff_t pos, unsigned len, unsigned copied, struct page *page,
+		void *fsdata)
+{
+	int ret;
+
+	ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
+	if (ret < len)
+		jfs_write_failed(mapping, pos + len);
+	return ret;
+}
+
 static sector_t jfs_bmap(struct address_space *mapping, sector_t block)
 {
 	return generic_block_bmap(mapping, block, jfs_get_block);
@@ -346,7 +358,7 @@ const struct address_space_operations jfs_aops = {
 	.writepage	= jfs_writepage,
 	.writepages	= jfs_writepages,
 	.write_begin	= jfs_write_begin,
-	.write_end	= nobh_write_end,
+	.write_end	= jfs_write_end,
 	.bmap		= jfs_bmap,
 	.direct_IO	= jfs_direct_IO,
 };
@@ -399,7 +411,7 @@ void jfs_truncate(struct inode *ip)
 {
 	jfs_info("jfs_truncate: size = 0x%lx", (ulong) ip->i_size);
 
-	nobh_truncate_page(ip->i_mapping, ip->i_size, jfs_get_block);
+	block_truncate_page(ip->i_mapping, ip->i_size, jfs_get_block);
 
 	IWRITE_LOCK(ip, RDWRLOCK_NORMAL);
 	jfs_truncate_nolock(ip, ip->i_size);