xfs: fix access to upper inodes without inode64

If a filesystem is mounted without the inode64 mount option we
should still be able to access inodes not fitting into 32 bits, just
not created new ones. For this to work we need to make sure the
inode cache radix tree is initialized for all allocation groups, not
just those we plan to allocate inodes from. This patch makes sure
we initialize the inode cache radix tree for all allocation groups,
and also cleans xfs_initialize_perag up a bit to separate the
inode32 logical from the general perag structure setup.

Signed-off-by: Christoph Hellwig <[e-mail]>
Signed-off-by: Alex Elder <[e-mail]>

fs/xfs/linux-2.6/xfs_sync.c

···
 		struct xfs_perag	*pag;
 
 		pag = xfs_perag_get(mp, ag);
-		if (!pag->pag_ici_init) {
-			xfs_perag_put(pag);
-			continue;
-		}
 		error = xfs_inode_ag_walk(mp, pag, execute, flags, tag,
 						exclusive, &nr);
 		xfs_perag_put(pag);
···
 	down_read(&xfs_mount_list_lock);
 	list_for_each_entry(mp, &xfs_mount_list, m_mplist) {
 		for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
-
 			pag = xfs_perag_get(mp, ag);
-			if (!pag->pag_ici_init) {
-				xfs_perag_put(pag);
-				continue;
-			}
 			reclaimable += pag->pag_ici_reclaimable;
 			xfs_perag_put(pag);
 		}

fs/xfs/xfs_ag.h

···
 
 	atomic_t        pagf_fstrms;    /* # of filestreams active in this AG */
 
-	int		pag_ici_init;	/* incore inode cache initialised */
 	rwlock_t	pag_ici_lock;	/* incore inode lock */
 	struct radix_tree_root pag_ici_root;	/* incore inode cache root */
 	int		pag_ici_reclaimable;	/* reclaimable inodes */

fs/xfs/xfs_iget.c

···
 
 	/* get the perag structure and ensure that it's inode capable */
 	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ino));
-	if (!pag->pagi_inodeok)
-		return EINVAL;
-	ASSERT(pag->pag_ici_init);
 	agino = XFS_INO_TO_AGINO(mp, ino);
 
 again:

fs/xfs/xfs_inode.c

···
 	int			i;
 
 	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
-	ASSERT(pag->pagi_inodeok);
-	ASSERT(pag->pag_ici_init);
 
 	inodes_per_cluster = XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog;
 	ilist_size = inodes_per_cluster * sizeof(xfs_inode_t *);

fs/xfs/xfs_mount.c

···
 	return 0;
 }
 
-STATIC void
-xfs_initialize_perag_icache(
-	xfs_perag_t	*pag)
-{
-	if (!pag->pag_ici_init) {
-		rwlock_init(&pag->pag_ici_lock);
-		INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC);
-		pag->pag_ici_init = 1;
-	}
-}
-
 int
 xfs_initialize_perag(
 	xfs_mount_t	*mp,
···
 	xfs_agino_t	agino;
 	xfs_ino_t	ino;
 	xfs_sb_t	*sbp = &mp->m_sb;
-	xfs_ino_t	max_inum = XFS_MAXINUMBER_32;
 	int		error = -ENOMEM;
-
-	/* Check to see if the filesystem can overflow 32 bit inodes */
-	agino = XFS_OFFBNO_TO_AGINO(mp, sbp->sb_agblocks - 1, 0);
-	ino = XFS_AGINO_TO_INO(mp, agcount - 1, agino);
 
 	/*
 	 * Walk the current per-ag tree so we don't try to initialise AGs
···
 		}
 		if (!first_initialised)
 			first_initialised = index;
+
 		pag = kmem_zalloc(sizeof(*pag), KM_MAYFAIL);
 		if (!pag)
 			goto out_unwind;
+		pag->pag_agno = index;
+		pag->pag_mount = mp;
+		rwlock_init(&pag->pag_ici_lock);
+		INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC);
+
 		if (radix_tree_preload(GFP_NOFS))
 			goto out_unwind;
+
 		spin_lock(&mp->m_perag_lock);
 		if (radix_tree_insert(&mp->m_perag_tree, index, pag)) {
 			BUG();
···
 			error = -EEXIST;
 			goto out_unwind;
 		}
-		pag->pag_agno = index;
-		pag->pag_mount = mp;
 		spin_unlock(&mp->m_perag_lock);
 		radix_tree_preload_end();
 	}
 
-	/* Clear the mount flag if no inode can overflow 32 bits
-	 * on this filesystem, or if specifically requested..
+	/*
+	 * If we mount with the inode64 option, or no inode overflows
+	 * the legacy 32-bit address space clear the inode32 option.
 	 */
-	if ((mp->m_flags & XFS_MOUNT_SMALL_INUMS) && ino > max_inum) {
-		mp->m_flags |= XFS_MOUNT_32BITINODES;
-	} else {
-		mp->m_flags &= ~XFS_MOUNT_32BITINODES;
-	}
+	agino = XFS_OFFBNO_TO_AGINO(mp, sbp->sb_agblocks - 1, 0);
+	ino = XFS_AGINO_TO_INO(mp, agcount - 1, agino);
 
-	/* If we can overflow then setup the ag headers accordingly */
+	if ((mp->m_flags & XFS_MOUNT_SMALL_INUMS) && ino > XFS_MAXINUMBER_32)
+		mp->m_flags |= XFS_MOUNT_32BITINODES;
+	else
+		mp->m_flags &= ~XFS_MOUNT_32BITINODES;
+
 	if (mp->m_flags & XFS_MOUNT_32BITINODES) {
-		/* Calculate how much should be reserved for inodes to
-		 * meet the max inode percentage.
+		/*
+		 * Calculate how much should be reserved for inodes to meet
+		 * the max inode percentage.
 		 */
 		if (mp->m_maxicount) {
 			__uint64_t	icount;
···
 		} else {
 			max_metadata = agcount;
 		}
+
 		for (index = 0; index < agcount; index++) {
 			ino = XFS_AGINO_TO_INO(mp, index, agino);
-			if (ino > max_inum) {
+			if (ino > XFS_MAXINUMBER_32) {
 				index++;
 				break;
 			}
 
-			/* This ag is preferred for inodes */
 			pag = xfs_perag_get(mp, index);
 			pag->pagi_inodeok = 1;
 			if (index < max_metadata)
 				pag->pagf_metadata = 1;
-			xfs_initialize_perag_icache(pag);
 			xfs_perag_put(pag);
 		}
 	} else {
-		/* Setup default behavior for smaller filesystems */
 		for (index = 0; index < agcount; index++) {
 			pag = xfs_perag_get(mp, index);
 			pag->pagi_inodeok = 1;
-			xfs_initialize_perag_icache(pag);
 			xfs_perag_put(pag);
 		}
 	}
+
 	if (maxagi)
 		*maxagi = index;
 	return 0;