[XFS] A change to inode chunk allocation to try allocating the new chunk

contiguous with the most recently allocated chunk.  On a striped
filesystem, this will fill a stripe unit with inodes before allocating new
inodes in another stripe unit.

SGI-PV: 951416
SGI-Modid: xfs-linux-melb:xfs-kern:208488a

Signed-off-by: Glen Overby <overby@sgi.com>
Signed-off-by: Nathan Scott <nathans@sgi.com>

fs/xfs/xfs_ialloc.c

@@ -136,7 +136,7 @@ xfs_ialloc_ag_alloc(
 	int		ninodes;	/* num inodes per buf */
 	xfs_agino_t	thisino;	/* current inode number, for loop */
 	int		version;	/* inode version number to use */
-	int		isaligned;	/* inode allocation at stripe unit */
+	int		isaligned = 0;	/* inode allocation at stripe unit */
 					/* boundary */
 
 	args.tp = tp;
@@ -152,47 +152,75 @@ xfs_ialloc_ag_alloc(
 		return XFS_ERROR(ENOSPC);
 	args.minlen = args.maxlen = XFS_IALLOC_BLOCKS(args.mp);
 	/*
-	 * Set the alignment for the allocation.
-	 * If stripe alignment is turned on then align at stripe unit
-	 * boundary.
-	 * If the cluster size is smaller than a filesystem block
-	 * then we're doing I/O for inodes in filesystem block size pieces,
-	 * so don't need alignment anyway.
-	 */
-	isaligned = 0;
-	if (args.mp->m_sinoalign) {
-		ASSERT(!(args.mp->m_flags & XFS_MOUNT_NOALIGN));
-		args.alignment = args.mp->m_dalign;
-		isaligned = 1;
-	} else if (XFS_SB_VERSION_HASALIGN(&args.mp->m_sb) &&
-	    args.mp->m_sb.sb_inoalignmt >=
-	    XFS_B_TO_FSBT(args.mp, XFS_INODE_CLUSTER_SIZE(args.mp)))
-		args.alignment = args.mp->m_sb.sb_inoalignmt;
-	else
-		args.alignment = 1;
+	 * First try to allocate inodes contiguous with the last-allocated
+	 * chunk of inodes.  If the filesystem is striped, this will fill
+	 * an entire stripe unit with inodes.
+ 	 */
 	agi = XFS_BUF_TO_AGI(agbp);
-	/*
-	 * Need to figure out where to allocate the inode blocks.
-	 * Ideally they should be spaced out through the a.g.
-	 * For now, just allocate blocks up front.
-	 */
-	args.agbno = be32_to_cpu(agi->agi_root);
-	args.fsbno = XFS_AGB_TO_FSB(args.mp, be32_to_cpu(agi->agi_seqno),
-				    args.agbno);
-	/*
-	 * Allocate a fixed-size extent of inodes.
-	 */
-	args.type = XFS_ALLOCTYPE_NEAR_BNO;
-	args.mod = args.total = args.wasdel = args.isfl = args.userdata =
-		args.minalignslop = 0;
-	args.prod = 1;
-	/*
-	 * Allow space for the inode btree to split.
-	 */
-	args.minleft = XFS_IN_MAXLEVELS(args.mp) - 1;
-	if ((error = xfs_alloc_vextent(&args)))
-		return error;
+	newino = be32_to_cpu(agi->agi_newino);
+	if(likely(newino != NULLAGINO)) {
+		args.agbno = XFS_AGINO_TO_AGBNO(args.mp, newino) +
+				XFS_IALLOC_BLOCKS(args.mp);
+		args.fsbno = XFS_AGB_TO_FSB(args.mp,
+				be32_to_cpu(agi->agi_seqno), args.agbno);
+		args.type = XFS_ALLOCTYPE_THIS_BNO;
+		args.mod = args.total = args.wasdel = args.isfl =
+			args.userdata = args.minalignslop = 0;
+		args.prod = 1;
+		args.alignment = 1;
+		/*
+		 * Allow space for the inode btree to split.
+		 */
+		args.minleft = XFS_IN_MAXLEVELS(args.mp) - 1;
+		if ((error = xfs_alloc_vextent(&args)))
+			return error;
+	} else
+		args.fsbno = NULLFSBLOCK;
 
+	if (unlikely(args.fsbno == NULLFSBLOCK)) {
+		/*
+		 * Set the alignment for the allocation.
+		 * If stripe alignment is turned on then align at stripe unit
+		 * boundary.
+		 * If the cluster size is smaller than a filesystem block 
+		 * then we're doing I/O for inodes in filesystem block size 
+		 * pieces, so don't need alignment anyway.
+		 */
+		isaligned = 0;
+		if (args.mp->m_sinoalign) {
+			ASSERT(!(args.mp->m_flags & XFS_MOUNT_NOALIGN));
+			args.alignment = args.mp->m_dalign;
+			isaligned = 1;
+		} else if (XFS_SB_VERSION_HASALIGN(&args.mp->m_sb) &&
+			   args.mp->m_sb.sb_inoalignmt >= 
+			   XFS_B_TO_FSBT(args.mp,
+			  	XFS_INODE_CLUSTER_SIZE(args.mp)))
+				args.alignment = args.mp->m_sb.sb_inoalignmt;
+		else
+			args.alignment = 1;
+		/*
+		 * Need to figure out where to allocate the inode blocks.
+		 * Ideally they should be spaced out through the a.g.
+		 * For now, just allocate blocks up front.
+		 */
+		args.agbno = be32_to_cpu(agi->agi_root);
+		args.fsbno = XFS_AGB_TO_FSB(args.mp,
+				be32_to_cpu(agi->agi_seqno), args.agbno);
+		/*
+		 * Allocate a fixed-size extent of inodes.
+		 */
+		args.type = XFS_ALLOCTYPE_NEAR_BNO;
+		args.mod = args.total = args.wasdel = args.isfl =
+			args.userdata = args.minalignslop = 0;
+		args.prod = 1;
+		/*
+		 * Allow space for the inode btree to split.
+		 */
+		args.minleft = XFS_IN_MAXLEVELS(args.mp) - 1;
+		if ((error = xfs_alloc_vextent(&args)))
+			return error;
+	}
+ 
 	/*
 	 * If stripe alignment is turned on, then try again with cluster
 	 * alignment.