xfs: fix corruptions in the directory tree

Repair corruptions in the directory tree itself.  Cycles are broken by
removing an incoming parent->child link.  Multiply-owned directories are
fixed by pruning the extra parent -> child links  Disconnected subtrees
are reconnected to the lost and found.

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

1 files changed, 29 insertions, 0 deletions

diff --git a/fs/xfs/scrub/dirtree.h b/fs/xfs/scrub/dirtree.h
index 2ddbcf43c291..1e1686365c61 100644
--- a/fs/xfs/scrub/dirtree.h
+++ b/fs/xfs/scrub/dirtree.h
@@ -26,6 +26,11 @@ enum xchk_dirpath_outcome {
 	XCHK_DIRPATH_LOOP,		/* cycle detected further up */
 	XCHK_DIRPATH_STALE,		/* path is stale */
 	XCHK_DIRPATH_OK,		/* path reaches the root */
+
+	XREP_DIRPATH_DELETING,		/* path is being deleted */
+	XREP_DIRPATH_DELETED,		/* path has been deleted */
+	XREP_DIRPATH_ADOPTING,		/* path is being adopted */
+	XREP_DIRPATH_ADOPTED,		/* path has been adopted */
 };
 
 /*
@@ -64,6 +69,9 @@ struct xchk_dirtree_outcomes {
 
 	/* Number of XCHK_DIRPATH_OK */
 	unsigned int		good;
+
+	/* Directory needs to be added to lost+found */
+	bool			needs_adoption;
 };
 
 struct xchk_dirtree {
@@ -79,6 +87,14 @@ struct xchk_dirtree {
 	 */
 	xfs_ino_t		scan_ino;
 
+	/*
+	 * If we start deleting redundant paths to this subdirectory, this is
+	 * the inode number of the surviving parent and the dotdot entry will
+	 * be set to this value.  If the value is NULLFSINO, then use @root_ino
+	 * as a stand-in until the orphanage can adopt the subdirectory.
+	 */
+	xfs_ino_t		parent_ino;
+
 	/* Scratch buffer for scanning pptr xattrs */
 	struct xfs_parent_rec	pptr_rec;
 	struct xfs_da_args	pptr_args;
@@ -87,12 +103,18 @@ struct xchk_dirtree {
 	struct xfs_name		xname;
 	char			namebuf[MAXNAMELEN];
 
+	/* Information for reparenting this directory. */
+	struct xrep_adoption	adoption;
+
 	/*
 	 * Hook into directory updates so that we can receive live updates
 	 * from other writer threads.
 	 */
 	struct xfs_dir_hook	dhook;
 
+	/* Parent pointer update arguments. */
+	struct xfs_parent_args	ppargs;
+
 	/* lock for everything below here */
 	struct mutex		lock;
 
@@ -146,4 +168,11 @@ xchk_dirtree_parentless(const struct xchk_dirtree *dl)
 	return false;
 }
 
+int xchk_dirtree_find_paths_to_root(struct xchk_dirtree *dl);
+int xchk_dirpath_append(struct xchk_dirtree *dl, struct xfs_inode *ip,
+		struct xchk_dirpath *path, const struct xfs_name *name,
+		const struct xfs_parent_rec *pptr);
+void xchk_dirtree_evaluate(struct xchk_dirtree *dl,
+		struct xchk_dirtree_outcomes *oc);
+
 #endif /* __XFS_SCRUB_DIRTREE_H__ */