[XFS] Rework DMAPI bulkstat calls in such a way that we can directly

extract inline attributes out of the bulkstat buffer (for that case),
rather than using an (extremely expensive for large icount filesystems)
iget for fetching attrs.

SGI-PV: 944409
SGI-Modid: xfs-linux-melb:xfs-kern:26602a
Signed-off-by: Nathan Scott <nathans@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>

fs/xfs/xfs_itable.c

@@ -252,6 +252,46 @@ xfs_bulkstat_one(
 	return error;
 }
 
+/*
+ * Test to see whether we can use the ondisk inode directly, based
+ * on the given bulkstat flags, filling in dipp accordingly.
+ * Returns zero if the inode is dodgey.
+ */
+STATIC int
+xfs_bulkstat_use_dinode(
+	xfs_mount_t	*mp,
+	int		flags,
+	xfs_buf_t	*bp,
+	int		clustidx,
+	xfs_dinode_t	**dipp)
+{
+	xfs_dinode_t	*dip;
+	unsigned int	aformat;
+
+	*dipp = NULL;
+	if (!bp || (flags & BULKSTAT_FG_IGET))
+		return 1;
+	dip = (xfs_dinode_t *)
+			xfs_buf_offset(bp, clustidx << mp->m_sb.sb_inodelog);
+	if (INT_GET(dip->di_core.di_magic, ARCH_CONVERT) != XFS_DINODE_MAGIC ||
+	    !XFS_DINODE_GOOD_VERSION(
+			INT_GET(dip->di_core.di_version, ARCH_CONVERT)))
+		return 0;
+	if (flags & BULKSTAT_FG_QUICK) {
+		*dipp = dip;
+		return 1;
+	}
+	/* BULKSTAT_FG_INLINE: if attr fork is local, or not there, use it */
+	aformat = INT_GET(dip->di_core.di_aformat, ARCH_CONVERT);
+	if ((XFS_CFORK_Q(&dip->di_core) == 0) ||
+	    (aformat == XFS_DINODE_FMT_LOCAL) ||
+	    (aformat == XFS_DINODE_FMT_EXTENTS && !dip->di_core.di_anextents)) {
+		*dipp = dip;
+		return 1;
+	}
+	return 1;
+}
+
 /*
  * Return stat information in bulk (by-inode) for the filesystem.
  */
@@ -529,7 +569,8 @@ xfs_bulkstat(
 						((chunkidx & nimask) >>
 						 mp->m_sb.sb_inopblog);
 
-					if (flags & BULKSTAT_FG_QUICK) {
+					if (flags & (BULKSTAT_FG_QUICK |
+						     BULKSTAT_FG_INLINE)) {
 						ino = XFS_AGINO_TO_INO(mp, agno,
 								       agino);
 						bno = XFS_AGB_TO_DADDR(mp, agno,
@@ -573,21 +614,25 @@ xfs_bulkstat(
 				be32_add(&irbp->ir_freecount, 1);
 				ino = XFS_AGINO_TO_INO(mp, agno, agino);
 				bno = XFS_AGB_TO_DADDR(mp, agno, agbno);
-				if (flags & BULKSTAT_FG_QUICK) {
-					dip = (xfs_dinode_t *)xfs_buf_offset(bp,
-					      (clustidx << mp->m_sb.sb_inodelog));
-
-					if (INT_GET(dip->di_core.di_magic, ARCH_CONVERT)
-						    != XFS_DINODE_MAGIC
-					    || !XFS_DINODE_GOOD_VERSION(
-						    INT_GET(dip->di_core.di_version, ARCH_CONVERT)))
+				if (!xfs_bulkstat_use_dinode(mp, flags, bp,
+							     clustidx, &dip))
 					continue;
+				/*
+				 * If we need to do an iget, cannot hold bp.
+				 * Drop it, until starting the next cluster.
+				 */
+				if ((flags & BULKSTAT_FG_INLINE) && !dip) {
+					if (bp)
+						xfs_buf_relse(bp);
+					bp = NULL;
 				}
 
 				/*
 				 * Get the inode and fill in a single buffer.
 				 * BULKSTAT_FG_QUICK uses dip to fill it in.
 				 * BULKSTAT_FG_IGET uses igets.
+				 * BULKSTAT_FG_INLINE uses dip if we have an
+				 * inline attr fork, else igets.
 				 * See: xfs_bulkstat_one & xfs_dm_bulkstat_one.
 				 * This is also used to count inodes/blks, etc
 				 * in xfs_qm_quotacheck.

fs/xfs/xfs_itable.h

@@ -45,6 +45,7 @@ typedef int (*bulkstat_one_pf)(struct xfs_mount	*mp,
  */
 #define BULKSTAT_FG_IGET	0x1	/* Go through the buffer cache */
 #define BULKSTAT_FG_QUICK	0x2	/* No iget, walk the dinode cluster */
+#define BULKSTAT_FG_INLINE	0x4	/* No iget if inline attrs */
 
 /*
  * Return stat information in bulk (by-inode) for the filesystem.