Merge tag 'metadata-directory-tree-6.13_2024-11-05' of https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into staging-merge

xfs: metadata inode directory trees [v5.5 03/10]

This series delivers a new feature -- metadata inode directories.  This
is a separate directory tree (rooted in the superblock) that contains
only inodes that contain filesystem metadata.  Different metadata
objects can be looked up with regular paths.

Start by creating xfs_imeta{dir,file}* functions to mediate access to
the metadata directory tree.  By the end of this mega series, all
existing metadata inodes (rt+quota) will use this directory tree instead
of the superblock.

Next, define the metadir on-disk format, which consists of marking
inodes with a new iflag that says they're metadata.  This prevents
bulkstat and friends from ever getting their hands on fs metadata files.

With a bit of luck, this should all go splendidly.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

1 files changed, 31 insertions, 4 deletions

diff --git a/fs/xfs/scrub/inode.c b/fs/xfs/scrub/inode.c
index d32716fb2fec..25ee66e7649d 100644
--- a/fs/xfs/scrub/inode.c
+++ b/fs/xfs/scrub/inode.c
@@ -60,6 +60,22 @@ xchk_install_handle_iscrub(
 	if (error)
 		return error;
 
+	/*
+	 * Don't allow scrubbing by handle of any non-directory inode records
+	 * in the metadata directory tree.  We don't know if any of the scans
+	 * launched by this scrubber will end up indirectly trying to lock this
+	 * file.
+	 *
+	 * Scrubbers of inode-rooted metadata files (e.g. quota files) will
+	 * attach all the resources needed to scrub the inode and call
+	 * xchk_inode directly.  Userspace cannot call this directly.
+	 */
+	if (xfs_is_metadir_inode(ip) && !S_ISDIR(VFS_I(ip)->i_mode)) {
+		xchk_irele(sc, ip);
+		sc->ip = NULL;
+		return -ENOENT;
+	}
+
 	return xchk_prepare_iscrub(sc);
 }
 
@@ -94,9 +110,15 @@ xchk_setup_inode(
 		return xchk_prepare_iscrub(sc);
 	}
 
-	/* Reject internal metadata files and obviously bad inode numbers. */
-	if (xfs_internal_inum(mp, sc->sm->sm_ino))
+	/*
+	 * On pre-metadir filesystems, reject internal metadata files.  For
+	 * metadir filesystems, limited scrubbing of any file in the metadata
+	 * directory tree by handle is allowed, because that is the only way to
+	 * validate the lack of parent pointers in the sb-root metadata inodes.
+	 */
+	if (!xfs_has_metadir(mp) && xfs_is_sb_inum(mp, sc->sm->sm_ino))
 		return -ENOENT;
+	/* Reject obviously bad inode numbers. */
 	if (!xfs_verify_ino(sc->mp, sc->sm->sm_ino))
 		return -ENOENT;
 
@@ -421,8 +443,13 @@ xchk_dinode(
 		break;
 	case 2:
 	case 3:
-		if (dip->di_onlink != 0)
-			xchk_ino_set_corrupt(sc, ino);
+		if (xfs_dinode_is_metadir(dip)) {
+			if (be16_to_cpu(dip->di_metatype) >= XFS_METAFILE_MAX)
+				xchk_ino_set_corrupt(sc, ino);
+		} else {
+			if (dip->di_metatype != 0)
+				xchk_ino_set_corrupt(sc, ino);
+		}
 
 		if (dip->di_mode == 0 && sc->ip)
 			xchk_ino_set_corrupt(sc, ino);