xfs: introduce xfs_bulkstat_ichunk_ra

From: Jie Liu <jeff.liu@oracle.com>

Introduce xfs_bulkstat_ichunk_ra() to loop over all clusters in the
next inode chunk, then performs readahead if there are any allocated
inodes in that cluster.

Refactor xfs_bulkstat() with it.
Signed-off-by: NJie Liu <jeff.liu@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDave Chinner <david@fromorbit.com>

fs/xfs/xfs_itable.c

@@ -172,6 +172,37 @@ xfs_bulkstat_one(
 				    xfs_bulkstat_one_fmt, ubused, stat);
 }
 
+/*
+ * Loop over all clusters in a chunk for a given incore inode allocation btree
+ * record.  Do a readahead if there are any allocated inodes in that cluster.
+ */
+STATIC void
+xfs_bulkstat_ichunk_ra(
+	struct xfs_mount		*mp,
+	xfs_agnumber_t			agno,
+	struct xfs_inobt_rec_incore	*irec)
+{
+	xfs_agblock_t			agbno;
+	struct blk_plug			plug;
+	int				blks_per_cluster;
+	int				inodes_per_cluster;
+	int				i;	/* inode chunk index */
+
+	agbno = XFS_AGINO_TO_AGBNO(mp, irec->ir_startino);
+	blks_per_cluster = xfs_icluster_size_fsb(mp);
+	inodes_per_cluster = blks_per_cluster << mp->m_sb.sb_inopblog;
+
+	blk_start_plug(&plug);
+	for (i = 0; i < XFS_INODES_PER_CHUNK;
+	     i += inodes_per_cluster, agbno += blks_per_cluster) {
+		if (xfs_inobt_maskn(i, inodes_per_cluster) & ~irec->ir_free) {
+			xfs_btree_reada_bufs(mp, agno, agbno, blks_per_cluster,
+					     &xfs_inode_buf_ops);
+		}
+	}
+	blk_finish_plug(&plug);
+}
+
 #define XFS_BULKSTAT_UBLEFT(ubleft)	((ubleft) >= statstruct_size)
 
 /*
@@ -187,7 +218,6 @@ xfs_bulkstat(
 	char			__user *ubuffer, /* buffer with inode stats */
 	int			*done)	/* 1 if there are more stats to get */
 {
-	xfs_agblock_t		agbno=0;/* allocation group block number */
 	xfs_buf_t		*agbp;	/* agi header buffer */
 	xfs_agi_t		*agi;	/* agi header data */
 	xfs_agino_t		agino;	/* inode # in allocation group */
@@ -206,8 +236,6 @@ xfs_bulkstat(
 	xfs_inobt_rec_incore_t	*irbuf;	/* start of irec buffer */
 	xfs_inobt_rec_incore_t	*irbufend; /* end of good irec buffer entries */
 	xfs_ino_t		lastino; /* last inode number returned */
-	int			blks_per_cluster; /* # of blocks per cluster */
-	int			inodes_per_cluster;/* # of inodes per cluster */
 	int			nirbuf;	/* size of irbuf */
 	int			rval;	/* return value error code */
 	int			tmp;	/* result value from btree calls */
@@ -237,8 +265,6 @@ xfs_bulkstat(
 	*done = 0;
 	fmterror = 0;
 	ubufp = ubuffer;
-	blks_per_cluster = xfs_icluster_size_fsb(mp);
-	inodes_per_cluster = blks_per_cluster << mp->m_sb.sb_inopblog;
 	irbuf = kmem_zalloc_greedy(&irbsize, PAGE_SIZE, PAGE_SIZE * 4);
 	if (!irbuf)
 		return -ENOMEM;
@@ -347,25 +373,7 @@ xfs_bulkstat(
 			 * Also start read-ahead now for this chunk.
 			 */
 			if (r.ir_freecount < XFS_INODES_PER_CHUNK) {
-				struct blk_plug	plug;
-				/*
-				 * Loop over all clusters in the next chunk.
-				 * Do a readahead if there are any allocated
-				 * inodes in that cluster.
-				 */
-				blk_start_plug(&plug);
-				agbno = XFS_AGINO_TO_AGBNO(mp, r.ir_startino);
-				for (chunkidx = 0;
-				     chunkidx < XFS_INODES_PER_CHUNK;
-				     chunkidx += inodes_per_cluster,
-				     agbno += blks_per_cluster) {
-					if (xfs_inobt_maskn(chunkidx,
-					    inodes_per_cluster) & ~r.ir_free)
-						xfs_btree_reada_bufs(mp, agno,
-							agbno, blks_per_cluster,
-							&xfs_inode_buf_ops);
-				}
-				blk_finish_plug(&plug);
+				xfs_bulkstat_ichunk_ra(mp, agno, &r);
 				irbp->ir_startino = r.ir_startino;
 				irbp->ir_freecount = r.ir_freecount;
 				irbp->ir_free = r.ir_free;