[XFS] Drop unneeded endian conversion in bulkstat and start readahead for

batches of inode cluster buffers at once, before any blocking reads are
issued.

SGI-PV: 944409
SGI-Modid: xfs-linux-melb:xfs-kern:26606a
Signed-off-by: Nathan Scott <nathans@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>

fs/xfs/xfs_itable.c

@@ -325,9 +325,9 @@ xfs_bulkstat(
 	int			i;	/* loop index */
 	int			icount;	/* count of inodes good in irbuf */
 	xfs_ino_t		ino;	/* inode number (filesystem) */
-	xfs_inobt_rec_t		*irbp;	/* current irec buffer pointer */
-	xfs_inobt_rec_t		*irbuf;	/* start of irec buffer */
-	xfs_inobt_rec_t		*irbufend; /* end of good irec buffer entries */
+	xfs_inobt_rec_incore_t	*irbp;	/* current irec buffer pointer */
+	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=0; /* last inode number returned */
 	int			nbcluster; /* # of blocks in a cluster */
 	int			nicluster; /* # of inodes in a cluster */
@@ -435,9 +435,9 @@ xfs_bulkstat(
 						gcnt++;
 				}
 				gfree |= XFS_INOBT_MASKN(0, chunkidx);
-				irbp->ir_startino = cpu_to_be32(gino);
-				irbp->ir_freecount = cpu_to_be32(gcnt);
-				irbp->ir_free = cpu_to_be64(gfree);
+				irbp->ir_startino = gino;
+				irbp->ir_freecount = gcnt;
+				irbp->ir_free = gfree;
 				irbp++;
 				agino = gino + XFS_INODES_PER_CHUNK;
 				icount = XFS_INODES_PER_CHUNK - gcnt;
@@ -491,11 +491,27 @@ xfs_bulkstat(
 			}
 			/*
 			 * If this chunk has any allocated inodes, save it.
+			 * Also start read-ahead now for this chunk.
 			 */
 			if (gcnt < XFS_INODES_PER_CHUNK) {
-				irbp->ir_startino = cpu_to_be32(gino);
-				irbp->ir_freecount = cpu_to_be32(gcnt);
-				irbp->ir_free = cpu_to_be64(gfree);
+				/*
+				 * Loop over all clusters in the next chunk.
+				 * Do a readahead if there are any allocated
+				 * inodes in that cluster.
+				 */
+				for (agbno = XFS_AGINO_TO_AGBNO(mp, gino),
+				     chunkidx = 0;
+				     chunkidx < XFS_INODES_PER_CHUNK;
+				     chunkidx += nicluster,
+				     agbno += nbcluster) {
+					if (XFS_INOBT_MASKN(chunkidx,
+							    nicluster) & ~gfree)
+						xfs_btree_reada_bufs(mp, agno,
+							agbno, nbcluster);
+				}
+				irbp->ir_startino = gino;
+				irbp->ir_freecount = gcnt;
+				irbp->ir_free = gfree;
 				irbp++;
 				icount += XFS_INODES_PER_CHUNK - gcnt;
 			}
@@ -518,34 +534,12 @@ xfs_bulkstat(
 		irbufend = irbp;
 		for (irbp = irbuf;
 		     irbp < irbufend && ubleft >= statstruct_size; irbp++) {
-			/*
-			 * Read-ahead the next chunk's worth of inodes.
-			 */
-			if (&irbp[1] < irbufend) {
-				/*
-				 * Loop over all clusters in the next chunk.
-				 * Do a readahead if there are any allocated
-				 * inodes in that cluster.
-				 */
-				for (agbno = XFS_AGINO_TO_AGBNO(mp,
-							be32_to_cpu(irbp[1].ir_startino)),
-				     chunkidx = 0;
-				     chunkidx < XFS_INODES_PER_CHUNK;
-				     chunkidx += nicluster,
-				     agbno += nbcluster) {
-					if (XFS_INOBT_MASKN(chunkidx,
-							    nicluster) &
-					    ~(be64_to_cpu(irbp[1].ir_free)))
-						xfs_btree_reada_bufs(mp, agno,
-							agbno, nbcluster);
-				}
-			}
 			/*
 			 * Now process this chunk of inodes.
 			 */
-			for (agino = be32_to_cpu(irbp->ir_startino), chunkidx = 0, clustidx = 0;
+			for (agino = irbp->ir_startino, chunkidx = clustidx = 0;
 			     ubleft > 0 &&
-				be32_to_cpu(irbp->ir_freecount) < XFS_INODES_PER_CHUNK;
+				irbp->ir_freecount < XFS_INODES_PER_CHUNK;
 			     chunkidx++, clustidx++, agino++) {
 				ASSERT(chunkidx < XFS_INODES_PER_CHUNK);
 				/*
@@ -565,7 +559,7 @@ xfs_bulkstat(
 				 */
 				if ((chunkidx & (nicluster - 1)) == 0) {
 					agbno = XFS_AGINO_TO_AGBNO(mp,
-							be32_to_cpu(irbp->ir_startino)) +
+							irbp->ir_startino) +
 						((chunkidx & nimask) >>
 						 mp->m_sb.sb_inopblog);
 
@@ -605,13 +599,13 @@ xfs_bulkstat(
 				/*
 				 * Skip if this inode is free.
 				 */
-				if (XFS_INOBT_MASK(chunkidx) & be64_to_cpu(irbp->ir_free))
+				if (XFS_INOBT_MASK(chunkidx) & irbp->ir_free)
 					continue;
 				/*
 				 * Count used inodes as free so we can tell
 				 * when the chunk is used up.
 				 */
-				be32_add(&irbp->ir_freecount, 1);
+				irbp->ir_freecount++;
 				ino = XFS_AGINO_TO_INO(mp, agno, agino);
 				bno = XFS_AGB_TO_DADDR(mp, agno, agbno);
 				if (!xfs_bulkstat_use_dinode(mp, flags, bp,