ocfs2: fix wrong check in ocfs2_direct_IO_get_blocks

contig_blocks gotten from ocfs2_extent_map_get_blocks cannot be compared
with clusters_to_alloc. So convert it to clusters first.

Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Reviewed-by: Weiwei Wang <wangww631@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 460c6c3..690ddc6 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -717,6 +717,16 @@
 	return (u64)clusters << c_to_b_bits;
 }
 
+static inline u32 ocfs2_clusters_for_blocks(struct super_block *sb,
+		u64 blocks)
+{
+	int b_to_c_bits = OCFS2_SB(sb)->s_clustersize_bits -
+			sb->s_blocksize_bits;
+
+	blocks += (1 << b_to_c_bits) - 1;
+	return (u32)(blocks >> b_to_c_bits);
+}
+
 static inline u32 ocfs2_blocks_to_clusters(struct super_block *sb,
 					   u64 blocks)
 {