udf: move calculating of nr_groups into helper function

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Ben Fennema <bfennema@falcon.csc.calpoly.edu>
Acked-by: Jan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
index 2c05f82..d9adb0f 100644
--- a/fs/udf/udf_sb.h
+++ b/fs/udf/udf_sb.h
@@ -43,6 +43,8 @@
 
 struct logicalVolIntegrityDescImpUse *udf_sb_lvidiu(struct udf_sb_info *sbi);
 
+int udf_compute_nr_groups(struct super_block *sb, u32 partition);
+
 #define UDF_QUERY_FLAG(X,Y)			( UDF_SB(X)->s_flags & ( 1 << (Y) ) )
 #define UDF_SET_FLAG(X,Y)			( UDF_SB(X)->s_flags |= ( 1 << (Y) ) )
 #define UDF_CLEAR_FLAG(X,Y)			( UDF_SB(X)->s_flags &= ~( 1 << (Y) ) )