[PATCH 4/6] xfs: fully check the parent handle when it points to the rootdir

From: Darrick J. Wong <[email protected]>

LOLLM noticed that the directory tree path checking declares the path to
be ok if the inumber in the parent pointer reaches the root directory.
Unfortunately, it neglects to check that the generation is correct.  Fix
that by moving the generation check up.

Cc: <[email protected]> # v6.10
Fixes: 928b721a11789a ("xfs: teach online scrub to find directory tree structure problems")
Signed-off-by: "Darrick J. Wong" <[email protected]>
Assisted-by: LOLLM # finding obvious bugs
---
 fs/xfs/scrub/dirtree.c |   16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)


diff --git a/fs/xfs/scrub/dirtree.c b/fs/xfs/scrub/dirtree.c
index c6a210f7508fc2..b2cf6e5439d915 100644
--- a/fs/xfs/scrub/dirtree.c
+++ b/fs/xfs/scrub/dirtree.c
@@ -383,6 +383,14 @@ xchk_dirpath_step_up(
 		goto out_scanlock;
 	}
 
+	/* The handle encoded in the parent pointer must match. */
+	if (VFS_I(dp)->i_generation != be32_to_cpu(dl->pptr_rec.p_gen)) {
+		trace_xchk_dirpath_badgen(dl->sc, dp, path->path_nr,
+				path->nr_steps, &dl->xname, &dl->pptr_rec);
+		error = -EFSCORRUPTED;
+		goto out_scanlock;
+	}
+
 	/* We've reached the root directory; the path is ok. */
 	if (parent_ino == dl->root_ino) {
 		xchk_dirpath_set_outcome(dl, path, XCHK_DIRPATH_OK);
@@ -411,14 +419,6 @@ xchk_dirpath_step_up(
 		goto out_scanlock;
 	}
 
-	/* The handle encoded in the parent pointer must match. */
-	if (VFS_I(dp)->i_generation != be32_to_cpu(dl->pptr_rec.p_gen)) {
-		trace_xchk_dirpath_badgen(dl->sc, dp, path->path_nr,
-				path->nr_steps, &dl->xname, &dl->pptr_rec);
-		error = -EFSCORRUPTED;
-		goto out_scanlock;
-	}
-
 	/* Parent pointer must point up to a directory. */
 	if (!S_ISDIR(VFS_I(dp)->i_mode)) {
 		trace_xchk_dirpath_nondir_parent(dl->sc, dp, path->path_nr,