[077/115] xfs: check dirents have parent pointers

Commit Message

Darrick J. Wong July 30, 2024, 12:43 a.m. UTC

From: Darrick J. Wong <[e-mail]>

Source kernel commit: 61b3f0df5c235806d372aaf696ce9aee7746d18f

If the fs has parent pointers, we need to check that each child dirent
points to a file that has a parent pointer pointing back at us.

Signed-off-by: Darrick J. Wong <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
---
 libxfs/xfs_parent.c |   22 ++++++++++++++++++++++
 libxfs/xfs_parent.h |    5 +++++
 2 files changed, 27 insertions(+)

Patch

diff --git a/libxfs/xfs_parent.c b/libxfs/xfs_parent.c
index bb0465197..8c29ba61c 100644
--- a/libxfs/xfs_parent.c
+++ b/libxfs/xfs_parent.c
@@ -288,3 +288,25 @@  xfs_parent_from_attr(
 		*parent_gen = be32_to_cpu(rec->p_gen);
 	return 0;
 }
+
+/*
+ * Look up a parent pointer record (@parent_name -> @pptr) of @ip.
+ *
+ * Caller must hold at least ILOCK_SHARED.  The scratchpad need not be
+ * initialized.
+ *
+ * Returns 0 if the pointer is found, -ENOATTR if there is no match, or a
+ * negative errno.
+ */
+int
+xfs_parent_lookup(
+	struct xfs_trans		*tp,
+	struct xfs_inode		*ip,
+	const struct xfs_name		*parent_name,
+	struct xfs_parent_rec		*pptr,
+	struct xfs_da_args		*scratch)
+{
+	memset(scratch, 0, sizeof(struct xfs_da_args));
+	xfs_parent_da_args_init(scratch, tp, pptr, ip, ip->i_ino, parent_name);
+	return xfs_attr_get_ilocked(scratch);
+}
diff --git a/libxfs/xfs_parent.h b/libxfs/xfs_parent.h
index d7ab09e73..977885823 100644
--- a/libxfs/xfs_parent.h
+++ b/libxfs/xfs_parent.h
@@ -96,4 +96,9 @@  int xfs_parent_from_attr(struct xfs_mount *mp, unsigned int attr_flags,
 		const void *value, unsigned int valuelen,
 		xfs_ino_t *parent_ino, uint32_t *parent_gen);
 
+/* Repair functions */
+int xfs_parent_lookup(struct xfs_trans *tp, struct xfs_inode *ip,
+		const struct xfs_name *name, struct xfs_parent_rec *pptr,
+		struct xfs_da_args *scratch);
+
 #endif /* __XFS_PARENT_H__ */