[PATCH v2 13/18] xfs: add parent attributes to link

[Allison Henderson <allison.henderson@xxxxxxxxxx>]

This patch modifies xfs_link to add a parent pointer to the inode.

[bfoster: rebase, use VFS inode fields, fix xfs_bmap_finish() usage]
[achender: rebased, changed __unint32_t to xfs_dir2_dataptr_t,
           fixed null pointer bugs]

Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
Signed-off-by: Allison Henderson <allison.henderson@xxxxxxxxxx>
---
 fs/xfs/xfs_inode.c | 43 ++++++++++++++++++++++++++++++++++---------
 1 file changed, 34 insertions(+), 9 deletions(-)

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index ef993c3a8963..6e5deb0d42c4 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1228,14 +1228,16 @@ xfs_create_tmpfile(
 
 int
 xfs_link(
-	xfs_inode_t		*tdp,
-	xfs_inode_t		*sip,
+	struct xfs_inode	*tdp,
+	struct xfs_inode	*sip,
 	struct xfs_name		*target_name)
 {
-	xfs_mount_t		*mp = tdp->i_mount;
-	xfs_trans_t		*tp;
+	struct xfs_mount	*mp = tdp->i_mount;
+	struct xfs_trans	*tp;
 	int			error, nospace_error = 0;
 	int			resblks;
+	xfs_dir2_dataptr_t	diroffset;
+	struct xfs_parent_defer	*parent = NULL;
 
 	trace_xfs_link(tdp, target_name);
 
@@ -1252,11 +1254,17 @@ xfs_link(
 	if (error)
 		goto std_return;
 
+	if (xfs_has_parent(mp)) {
+		error = xfs_parent_init(mp, sip, target_name, &parent);
+		if (error)
+			goto std_return;
+	}
+
 	resblks = XFS_LINK_SPACE_RES(mp, target_name->len);
 	error = xfs_trans_alloc_dir(tdp, &M_RES(mp)->tr_link, sip, &resblks,
 			&tp, &nospace_error);
 	if (error)
-		goto std_return;
+		goto drop_incompat;
 
 	/*
 	 * If we are using project inheritance, we only allow hard link
@@ -1289,14 +1297,26 @@ xfs_link(
 	}
 
 	error = xfs_dir_createname(tp, tdp, target_name, sip->i_ino,
-				   resblks, NULL);
+				   resblks, &diroffset);
 	if (error)
-		goto error_return;
+		goto out_defer_cancel;
 	xfs_trans_ichgtime(tp, tdp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 	xfs_trans_log_inode(tp, tdp, XFS_ILOG_CORE);
 
 	xfs_bumplink(tp, sip);
 
+	/*
+	 * If we have parent pointers, we now need to add the parent record to
+	 * the attribute fork of the inode. If this is the initial parent
+	 * attribute, we need to create it correctly, otherwise we can just add
+	 * the parent to the inode.
+	 */
+	if (parent) {
+		error = xfs_parent_defer_add(tp, tdp, parent, diroffset);
+		if (error)
+			goto out_defer_cancel;
+	}
+
 	/*
 	 * If this is a synchronous mount, make sure that the
 	 * link transaction goes to disk before returning to
@@ -1310,11 +1330,16 @@ xfs_link(
 	xfs_iunlock(sip, XFS_ILOCK_EXCL);
 	return error;
 
- error_return:
+out_defer_cancel:
+	xfs_defer_cancel(tp);
+error_return:
 	xfs_trans_cancel(tp);
 	xfs_iunlock(tdp, XFS_ILOCK_EXCL);
 	xfs_iunlock(sip, XFS_ILOCK_EXCL);
- std_return:
+drop_incompat:
+	if (parent)
+		xfs_parent_cancel(mp, parent);
+std_return:
 	if (error == -ENOSPC && nospace_error)
 		error = nospace_error;
 	return error;
-- 
2.25.1