From: Darrick J. Wong <djwong@xxxxxxxxxx>
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 <djwong@xxxxxxxxxx>
---
libxfs/xfs_parent.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++
libxfs/xfs_parent.h | 10 +++++++++
2 files changed, 64 insertions(+)
diff --git a/libxfs/xfs_parent.c b/libxfs/xfs_parent.c
index 92b541737cb..024e89756e6 100644
--- a/libxfs/xfs_parent.c
+++ b/libxfs/xfs_parent.c
@@ -367,3 +367,57 @@ xfs_parent_irec_hashname(
irec->p_namehash = xfs_dir2_hashname(mp, &dname);
}
+
+static inline void
+xfs_parent_scratch_init(
+ struct xfs_trans *tp,
+ struct xfs_inode *ip,
+ const struct xfs_parent_name_irec *pptr,
+ struct xfs_parent_scratch *scr)
+{
+ memset(&scr->args, 0, sizeof(struct xfs_da_args));
+ scr->args.attr_filter = XFS_ATTR_PARENT;
+ scr->args.dp = ip;
+ scr->args.geo = ip->i_mount->m_attr_geo;
+ scr->args.name = (const unsigned char *)&scr->rec;
+ scr->args.namelen = sizeof(struct xfs_parent_name_rec);
+ scr->args.op_flags = XFS_DA_OP_NVLOOKUP;
+ scr->args.trans = tp;
+ scr->args.value = (void *)pptr->p_name;
+ scr->args.valuelen = pptr->p_namelen;
+ scr->args.whichfork = XFS_ATTR_FORK;
+ scr->args.hashval = xfs_da_hashname((const void *)&scr->rec,
+ sizeof(struct xfs_parent_name_rec));
+}
+
+/*
+ * Look up the @name associated with the parent pointer (@pptr) of @ip.
+ * Caller must hold at least ILOCK_SHARED. Returns 0 if the pointer is found,
+ * -ENOATTR if there is no match, or a negative errno. The scratchpad need not
+ * be initialized.
+ */
+int
+xfs_parent_lookup(
+ struct xfs_trans *tp,
+ struct xfs_inode *ip,
+ const struct xfs_parent_name_irec *pptr,
+ struct xfs_parent_scratch *scr)
+{
+ int error;
+
+ /*
+ * Make sure the attr fork iext tree is loaded in transaction context
+ * before we start down the rest of the call path.
+ */
+ if (xfs_inode_hasattr(ip)) {
+ error = xfs_iread_extents(tp, ip, XFS_ATTR_FORK);
+ if (error)
+ return error;
+ }
+
+ xfs_parent_irec_to_disk(&scr->rec, pptr);
+ xfs_parent_scratch_init(tp, ip, pptr, scr);
+ scr->args.op_flags |= XFS_DA_OP_OKNOENT;
+
+ return xfs_attr_get_ilocked(&scr->args);
+}
diff --git a/libxfs/xfs_parent.h b/libxfs/xfs_parent.h
index e43ae5a7df8..e4443da1d86 100644
--- a/libxfs/xfs_parent.h
+++ b/libxfs/xfs_parent.h
@@ -152,4 +152,14 @@ void xfs_parent_irec_hashname(struct xfs_mount *mp,
bool xfs_parent_verify_irec(struct xfs_mount *mp,
const struct xfs_parent_name_irec *irec);
+/* Scratchpad memory so that raw parent operations don't burn stack space. */
+struct xfs_parent_scratch {
+ struct xfs_parent_name_rec rec;
+ struct xfs_da_args args;
+};
+
+int xfs_parent_lookup(struct xfs_trans *tp, struct xfs_inode *ip,
+ const struct xfs_parent_name_irec *pptr,
+ struct xfs_parent_scratch *scratch);
+
#endif /* __XFS_PARENT_H__ */
