xfs: scrub metadata directories

Teach online scrub about the metadata directory tree.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/scrub/dir.c

@@ -100,6 +100,14 @@ xchk_dir_check_ftype(
 
 	if (xfs_mode_to_ftype(VFS_I(ip)->i_mode) != ftype)
 		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);
+
+	/*
+	 * Metadata and regular inodes cannot cross trees.  This property
+	 * cannot change without a full inode free and realloc cycle, so it's
+	 * safe to check this without holding locks.
+	 */
+	if (xfs_is_metadir_inode(ip) != xfs_is_metadir_inode(sc->ip))
+		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, offset);
 }
 
 /*

fs/xfs/scrub/dir_repair.c

@@ -415,6 +415,12 @@ xrep_dir_salvage_entry(
 	if (error)
 		return 0;
 
+	/* Don't mix metadata and regular directory trees. */
+	if (xfs_is_metadir_inode(ip) != xfs_is_metadir_inode(rd->sc->ip)) {
+		xchk_irele(sc, ip);
+		return 0;
+	}
+
 	xname.type = xfs_mode_to_ftype(VFS_I(ip)->i_mode);
 	xchk_irele(sc, ip);
 

fs/xfs/scrub/dirtree.c

@@ -362,7 +362,8 @@ xchk_dirpath_set_outcome(
 STATIC int
 xchk_dirpath_step_up(
 	struct xchk_dirtree	*dl,
-	struct xchk_dirpath	*path)
+	struct xchk_dirpath	*path,
+	bool			is_metadir)
 {
 	struct xfs_scrub	*sc = dl->sc;
 	struct xfs_inode	*dp;
@@ -435,6 +436,14 @@ xchk_dirpath_step_up(
 		goto out_scanlock;
 	}
 
+	/* Parent must be in the same directory tree. */
+	if (is_metadir != xfs_is_metadir_inode(dp)) {
+		trace_xchk_dirpath_crosses_tree(dl->sc, dp, path->path_nr,
+				path->nr_steps, &dl->xname, &dl->pptr_rec);
+		error = -EFSCORRUPTED;
+		goto out_scanlock;
+	}
+
 	/*
 	 * If the extended attributes look as though they has been zapped by
 	 * the inode record repair code, we cannot scan for parent pointers.
@@ -508,6 +517,7 @@ xchk_dirpath_walk_upwards(
 	struct xchk_dirpath	*path)
 {
 	struct xfs_scrub	*sc = dl->sc;
+	bool			is_metadir;
 	int			error;
 
 	ASSERT(sc->ilock_flags & XFS_ILOCK_EXCL);
@@ -538,6 +548,7 @@ xchk_dirpath_walk_upwards(
 	 * ILOCK state is no longer tracked in the scrub context.  Hence we
 	 * must drop @sc->ip's ILOCK during the walk.
 	 */
+	is_metadir = xfs_is_metadir_inode(sc->ip);
 	mutex_unlock(&dl->lock);
 	xchk_iunlock(sc, XFS_ILOCK_EXCL);
 
@@ -547,7 +558,7 @@ xchk_dirpath_walk_upwards(
 	 * If we see any kind of error here (including corruptions), the parent
 	 * pointer of @sc->ip is corrupt.  Stop the whole scan.
 	 */
-	error = xchk_dirpath_step_up(dl, path);
+	error = xchk_dirpath_step_up(dl, path, is_metadir);
 	if (error) {
 		xchk_ilock(sc, XFS_ILOCK_EXCL);
 		mutex_lock(&dl->lock);
@@ -560,7 +571,7 @@ xchk_dirpath_walk_upwards(
 	 * *somewhere* in the path, but we don't need to stop scanning.
 	 */
 	while (!error && path->outcome == XCHK_DIRPATH_SCANNING)
-		error = xchk_dirpath_step_up(dl, path);
+		error = xchk_dirpath_step_up(dl, path, is_metadir);
 
 	/* Retake the locks we had, mark paths, etc. */
 	xchk_ilock(sc, XFS_ILOCK_EXCL);

fs/xfs/scrub/findparent.c

@@ -172,6 +172,10 @@ xrep_findparent_walk_directory(
 	 */
 	lock_mode = xfs_ilock_data_map_shared(dp);
 
+	/* Don't mix metadata and regular directory trees. */
+	if (xfs_is_metadir_inode(dp) != xfs_is_metadir_inode(sc->ip))
+		goto out_unlock;
+
 	/*
 	 * If this directory is known to be sick, we cannot scan it reliably
 	 * and must abort.
@@ -368,6 +372,12 @@ xrep_findparent_confirm(
 		return 0;
 	}
 
+	/* The metadata root directory always points to itself. */
+	if (sc->ip == sc->mp->m_metadirip) {
+		*parent_ino = sc->mp->m_sb.sb_metadirino;
+		return 0;
+	}
+
 	/* Unlinked dirs can point anywhere; point them up to the root dir. */
 	if (VFS_I(sc->ip)->i_nlink == 0) {
 		*parent_ino = xchk_inode_rootdir_inum(sc->ip);
@@ -415,6 +425,9 @@ xrep_findparent_self_reference(
 	if (sc->ip->i_ino == sc->mp->m_sb.sb_rootino)
 		return sc->mp->m_sb.sb_rootino;
 
+	if (sc->ip->i_ino == sc->mp->m_sb.sb_metadirino)
+		return sc->mp->m_sb.sb_metadirino;
+
 	if (VFS_I(sc->ip)->i_nlink == 0)
 		return xchk_inode_rootdir_inum(sc->ip);
 

fs/xfs/scrub/parent.c

@@ -132,6 +132,14 @@ xchk_parent_validate(
 		return 0;
 	}
 
+	/* Is this the metadata root dir?  Then '..' must point to itself. */
+	if (sc->ip == mp->m_metadirip) {
+		if (sc->ip->i_ino != mp->m_sb.sb_metadirino ||
+		    sc->ip->i_ino != parent_ino)
+			xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
+		return 0;
+	}
+
 	/* '..' must not point to ourselves. */
 	if (sc->ip->i_ino == parent_ino) {
 		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
@@ -185,6 +193,12 @@ xchk_parent_validate(
 		goto out_unlock;
 	}
 
+	/* Metadata and regular inodes cannot cross trees. */
+	if (xfs_is_metadir_inode(dp) != xfs_is_metadir_inode(sc->ip)) {
+		xchk_fblock_set_corrupt(sc, XFS_DATA_FORK, 0);
+		goto out_unlock;
+	}
+
 	/* Look for a directory entry in the parent pointing to the child. */
 	error = xchk_dir_walk(sc, dp, xchk_parent_actor, &spc);
 	if (!xchk_fblock_xref_process_error(sc, XFS_DATA_FORK, 0, &error))

fs/xfs/scrub/trace.h

@@ -1753,6 +1753,7 @@ DEFINE_XCHK_DIRPATH_EVENT(xchk_dirpath_badgen);
 DEFINE_XCHK_DIRPATH_EVENT(xchk_dirpath_nondir_parent);
 DEFINE_XCHK_DIRPATH_EVENT(xchk_dirpath_unlinked_parent);
 DEFINE_XCHK_DIRPATH_EVENT(xchk_dirpath_found_next_step);
+DEFINE_XCHK_DIRPATH_EVENT(xchk_dirpath_crosses_tree);
 
 TRACE_DEFINE_ENUM(XCHK_DIRPATH_SCANNING);
 TRACE_DEFINE_ENUM(XCHK_DIRPATH_DELETE);