diff --git a/fs/gfs2/bmap.h b/fs/gfs2/bmap.h
index 4e6cde2..c983177 100644
--- a/fs/gfs2/bmap.h
+++ b/fs/gfs2/bmap.h
@@ -10,10 +10,40 @@
 #ifndef __BMAP_DOT_H__
 #define __BMAP_DOT_H__
 
+#include "inode.h"
+
 struct inode;
 struct gfs2_inode;
 struct page;
 
+
+/**
+ * gfs2_write_calc_reserv - calculate number of blocks needed to write to a file
+ * @ip: the file
+ * @len: the number of bytes to be written to the file
+ * @data_blocks: returns the number of data blocks required
+ * @ind_blocks: returns the number of indirect blocks required
+ *
+ */
+
+static inline void gfs2_write_calc_reserv(const struct gfs2_inode *ip,
+					  unsigned int len,
+					  unsigned int *data_blocks,
+					  unsigned int *ind_blocks)
+{
+	const struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
+	unsigned int tmp;
+
+	BUG_ON(gfs2_is_dir(ip));
+	*data_blocks = (len >> sdp->sd_sb.sb_bsize_shift) + 3;
+	*ind_blocks = 3 * (sdp->sd_max_height - 1);
+
+	for (tmp = *data_blocks; tmp > sdp->sd_diptrs;) {
+		tmp = DIV_ROUND_UP(tmp, sdp->sd_inptrs);
+		*ind_blocks += tmp;
+	}
+}
+
 int gfs2_unstuff_dinode(struct gfs2_inode *ip, struct page *page);
 int gfs2_block_map(struct inode *inode, sector_t lblock, struct buffer_head *bh, int create);
 int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsigned *extlen);
@@ -21,10 +51,6 @@
 int gfs2_truncatei(struct gfs2_inode *ip, u64 size);
 int gfs2_truncatei_resume(struct gfs2_inode *ip);
 int gfs2_file_dealloc(struct gfs2_inode *ip);
-
-void gfs2_write_calc_reserv(struct gfs2_inode *ip, unsigned int len,
-			    unsigned int *data_blocks,
-			    unsigned int *ind_blocks);
 int gfs2_write_alloc_required(struct gfs2_inode *ip, u64 offset,
 			      unsigned int len, int *alloc_required);