GFS2: Streamline alloc calculations for writes

This patch removes some unused code, and make the calculation
of the number of blocks required conditional in order to reduce
the number of times this (potentially expensive) calculation
is done.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

1 files changed, 7 insertions, 42 deletions

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 789f28cfdc2..11ffc56f1f8 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -1231,35 +1231,6 @@ int gfs2_file_dealloc(struct gfs2_inode *ip)
 }
 
 /**
- * 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
- *
- */
-
-void gfs2_write_calc_reserv(struct gfs2_inode *ip, unsigned int len,
-			    unsigned int *data_blocks, unsigned int *ind_blocks)
-{
-	struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
-	unsigned int tmp;
-
-	if (gfs2_is_dir(ip)) {
-		*data_blocks = DIV_ROUND_UP(len, sdp->sd_jbsize) + 2;
-		*ind_blocks = 3 * (sdp->sd_max_jheight - 1);
-	} else {
-		*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;
-	}
-}
-
-/**
  * gfs2_write_alloc_required - figure out if a write will require an allocation
  * @ip: the file being written to
  * @offset: the offset to write to
@@ -1276,6 +1247,7 @@ int gfs2_write_alloc_required(struct gfs2_inode *ip, u64 offset,
 	struct buffer_head bh;
 	unsigned int shift;
 	u64 lblock, lblock_stop, size;
+	u64 end_of_file;
 
 	*alloc_required = 0;
 
@@ -1291,19 +1263,12 @@ int gfs2_write_alloc_required(struct gfs2_inode *ip, u64 offset,
 
 	*alloc_required = 1;
 	shift = sdp->sd_sb.sb_bsize_shift;
-	if (gfs2_is_dir(ip)) {
-		unsigned int bsize = sdp->sd_jbsize;
-		lblock = offset;
-		do_div(lblock, bsize);
-		lblock_stop = offset + len + bsize - 1;
-		do_div(lblock_stop, bsize);
-	} else {
-		u64 end_of_file = (ip->i_disksize + sdp->sd_sb.sb_bsize - 1) >> shift;
-		lblock = offset >> shift;
-		lblock_stop = (offset + len + sdp->sd_sb.sb_bsize - 1) >> shift;
-		if (lblock_stop > end_of_file)
-			return 0;
-	}
+	BUG_ON(gfs2_is_dir(ip));
+	end_of_file = (ip->i_disksize + sdp->sd_sb.sb_bsize - 1) >> shift;
+	lblock = offset >> shift;
+	lblock_stop = (offset + len + sdp->sd_sb.sb_bsize - 1) >> shift;
+	if (lblock_stop > end_of_file)
+		return 0;
 
 	size = (lblock_stop - lblock) << shift;
 	do {