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

[Allison Henderson <allison.henderson@oracle.com>]

From: Dave Chinner <dchinner@redhat.com>

This patch modifies xfs_link to add a parent pointer to the inode.
xfs_link will also need to create an attribute fork if the inode does
not already have one.

[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@redhat.com>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
---
 fs/xfs/xfs_inode.c | 60 +++++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 46 insertions(+), 14 deletions(-)

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 0cfdc2f..90498cb 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1417,6 +1417,8 @@ xfs_link(
 	struct xfs_defer_ops	dfops;
 	xfs_fsblock_t           first_block;
 	int			resblks;
+	xfs_dir2_dataptr_t	diroffset;
+	bool			first_parent = false;
 
 	trace_xfs_link(tdp, target_name);
 
@@ -1433,6 +1435,25 @@ xfs_link(
 	if (error)
 		goto std_return;
 
+	/*
+	 * If we have parent pointers and there is no attribute fork (i.e. we
+	 * are linking in a O_TMPFILE created inode) we need to add the
+	 * attribute fork to the inode. Because we may have an existing data
+	 * fork, we do this before we start the link transaction as adding an
+	 * attribute fork requires it's own transaction.
+	 */
+	if (xfs_sb_version_hasparent(&mp->m_sb) && !xfs_inode_hasattr(sip)) {
+		int sf_size = sizeof(struct xfs_attr_sf_hdr) +
+				XFS_ATTR_SF_ENTSIZE_BYNAME(
+					sizeof(struct xfs_parent_name_rec),
+					target_name->len);
+		ASSERT(VFS_I(sip)->i_nlink == 0);
+		error = xfs_bmap_add_attrfork(sip, sf_size, 0);
+		if (error)
+			goto std_return;
+		first_parent = true;
+	}
+
 	resblks = XFS_LINK_SPACE_RES(mp, target_name->len);
 	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_link, resblks, 0, 0, &tp);
 	if (error == -ENOSPC) {
@@ -1464,8 +1485,6 @@ xfs_link(
 			goto error_return;
 	}
 
-	xfs_defer_init(&dfops, &first_block);
-
 	/*
 	 * Handle initial link state of O_TMPFILE inode
 	 */
@@ -1475,36 +1494,49 @@ xfs_link(
 			goto error_return;
 	}
 
+	xfs_defer_init(&dfops, &first_block);
 	error = xfs_dir_createname(tp, tdp, target_name, sip->i_ino,
-				   &first_block, &dfops, resblks, NULL);
+				   &first_block, &dfops, 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);
 
 	error = xfs_bumplink(tp, sip);
 	if (error)
-		goto error_return;
+		goto out_defer_cancel;
 
 	/*
-	 * If this is a synchronous mount, make sure that the
-	 * link transaction goes to disk before returning to
-	 * the user.
+	 * 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 (xfs_sb_version_hasparent(&mp->m_sb)) {
+		error = xfs_parent_add_deferred(tdp, sip, target_name,
+				       diroffset, &dfops);
+		if (error)
+			goto out_defer_cancel;
+	}
+
+	/*
+	 * If this is a synchronous mount, make sure that the link transaction
+	 * goes to disk before returning to the user.
 	 */
 	if (mp->m_flags & (XFS_MOUNT_WSYNC|XFS_MOUNT_DIRSYNC))
 		xfs_trans_set_sync(tp);
 
 	error = xfs_defer_finish(&tp, &dfops);
-	if (error) {
-		xfs_defer_cancel(&dfops);
-		goto error_return;
-	}
+	if (error)
+		goto out_defer_cancel;
 
 	return xfs_trans_commit(tp);
 
- error_return:
+out_defer_cancel:
+	xfs_defer_cancel(&dfops);
+error_return:
 	xfs_trans_cancel(tp);
- std_return:
+std_return:
 	return error;
 }
 
-- 
2.7.4