[XFS] use the inode radix tree for reclaiming inodes

Use the reclaim tag to walk the radix tree and find the inodes under
reclaim. This was the only user of the deleted inode list.

SGI-PV: 988142

SGI-Modid: xfs-linux-melb:xfs-kern:32333a
Signed-off-by: David Chinner <david@fromorbit.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>

fs/xfs/linux-2.6/xfs_sync.c

@@ -685,32 +685,93 @@ xfs_inode_clear_reclaim_tag(
 	xfs_put_perag(mp, pag);
 }
 
-int
-xfs_reclaim_inodes(
+
+STATIC void
+xfs_reclaim_inodes_ag(
 	xfs_mount_t	*mp,
-	int		 noblock,
+	int		ag,
+	int		noblock,
 	int		mode)
 {
-	xfs_inode_t	*ip, *n;
+	xfs_inode_t	*ip = NULL;
+	xfs_perag_t	*pag = &mp->m_perag[ag];
+	int		nr_found;
+	int		first_index;
+	int		skipped;
 
 restart:
-	XFS_MOUNT_ILOCK(mp);
-	list_for_each_entry_safe(ip, n, &mp->m_del_inodes, i_reclaim) {
+	first_index = 0;
+	skipped = 0;
+	do {
+		/*
+		 * use a gang lookup to find the next inode in the tree
+		 * as the tree is sparse and a gang lookup walks to find
+		 * the number of objects requested.
+		 */
+		read_lock(&pag->pag_ici_lock);
+		nr_found = radix_tree_gang_lookup_tag(&pag->pag_ici_root,
+					(void**)&ip, first_index, 1,
+					XFS_ICI_RECLAIM_TAG);
+
+		if (!nr_found) {
+			read_unlock(&pag->pag_ici_lock);
+			break;
+		}
+
+		/* update the index for the next lookup */
+		first_index = XFS_INO_TO_AGINO(mp, ip->i_ino + 1);
+
+		ASSERT(xfs_iflags_test(ip, (XFS_IRECLAIMABLE|XFS_IRECLAIM)));
+
+		/* ignore if already under reclaim */
+		if (xfs_iflags_test(ip, XFS_IRECLAIM)) {
+			read_unlock(&pag->pag_ici_lock);
+			continue;
+		}
+
 		if (noblock) {
-			if (xfs_ilock_nowait(ip, XFS_ILOCK_EXCL) == 0)
+			if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL)) {
+				read_unlock(&pag->pag_ici_lock);
 				continue;
+			}
 			if (xfs_ipincount(ip) ||
 			    !xfs_iflock_nowait(ip)) {
 				xfs_iunlock(ip, XFS_ILOCK_EXCL);
+				read_unlock(&pag->pag_ici_lock);
 				continue;
 			}
 		}
-		XFS_MOUNT_IUNLOCK(mp);
+		read_unlock(&pag->pag_ici_lock);
+
+		/*
+		 * hmmm - this is an inode already in reclaim. Do
+		 * we even bother catching it here?
+		 */
 		if (xfs_reclaim_inode(ip, noblock, mode))
-			delay(1);
+			skipped++;
+	} while (nr_found);
+
+	if (skipped) {
+		delay(1);
 		goto restart;
 	}
-	XFS_MOUNT_IUNLOCK(mp);
+	return;
+
+}
+
+int
+xfs_reclaim_inodes(
+	xfs_mount_t	*mp,
+	int		 noblock,
+	int		mode)
+{
+	int		i;
+
+	for (i = 0; i < mp->m_sb.sb_agcount; i++) {
+		if (!mp->m_perag[i].pag_ici_init)
+			continue;
+		xfs_reclaim_inodes_ag(mp, i, noblock, mode);
+	}
 	return 0;
 }