[PATCH 16/28] xfs: add parent attributes to link

["Darrick J. Wong" <djwong@xxxxxxxxxx>]

From: Allison Henderson <allison.henderson@xxxxxxxxxx>

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

Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
Signed-off-by: Allison Henderson <allison.henderson@xxxxxxxxxx>
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
 fs/xfs/libxfs/xfs_trans_space.h |    2 -
 fs/xfs/xfs_inode.c              |   60 ++++++++++++++++++++++++++++++++++-----
 2 files changed, 53 insertions(+), 9 deletions(-)


diff --git a/fs/xfs/libxfs/xfs_trans_space.h b/fs/xfs/libxfs/xfs_trans_space.h
index 87b31c69a773..f72207923ec2 100644
--- a/fs/xfs/libxfs/xfs_trans_space.h
+++ b/fs/xfs/libxfs/xfs_trans_space.h
@@ -84,8 +84,6 @@
 	(2 * (mp)->m_alloc_maxlevels)
 #define	XFS_GROWFSRT_SPACE_RES(mp,b)	\
 	((b) + XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK))
-#define	XFS_LINK_SPACE_RES(mp,nl)	\
-	XFS_DIRENTER_SPACE_RES(mp,nl)
 #define	XFS_MKDIR_SPACE_RES(mp,nl)	\
 	(XFS_IALLOC_SPACE_RES(mp) + XFS_DIRENTER_SPACE_RES(mp,nl))
 #define	XFS_QM_DQALLOC_SPACE_RES(mp)	\
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index ba488310ea9c..b4318df03b5c 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1247,16 +1247,32 @@ xfs_create_tmpfile(
 	return error;
 }
 
+static unsigned int
+xfs_link_space_res(
+	struct xfs_mount	*mp,
+	unsigned int		namelen)
+{
+	unsigned int		ret;
+
+	ret = XFS_DIRENTER_SPACE_RES(mp, namelen);
+	if (xfs_has_parent(mp))
+		ret += xfs_pptr_calc_space_res(mp, namelen);
+
+	return ret;
+}
+
 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);
 
@@ -1273,11 +1289,25 @@ xfs_link(
 	if (error)
 		goto std_return;
 
-	resblks = XFS_LINK_SPACE_RES(mp, target_name->len);
+	error = xfs_parent_start(mp, &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 out_parent;
+
+	/*
+	 * We don't allow reservationless or quotaless hardlinking when parent
+	 * pointers are enabled because we can't back out if the xattrs must
+	 * grow.
+	 */
+	if (parent && nospace_error) {
+		error = nospace_error;
+		goto error_return;
+	}
 
 	/*
 	 * If we are using project inheritance, we only allow hard link
@@ -1310,7 +1340,7 @@ xfs_link(
 	}
 
 	error = xfs_dir_createname(tp, tdp, target_name, sip->i_ino,
-				   resblks, NULL);
+				   resblks, &diroffset);
 	if (error)
 		goto error_return;
 	xfs_trans_ichgtime(tp, tdp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
@@ -1318,6 +1348,19 @@ xfs_link(
 
 	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, parent, tdp, target_name,
+					     diroffset, sip);
+		if (error)
+			goto error_return;
+	}
+
 	/*
 	 * If this is a synchronous mount, make sure that the
 	 * link transaction goes to disk before returning to
@@ -1329,12 +1372,15 @@ xfs_link(
 	error = xfs_trans_commit(tp);
 	xfs_iunlock(tdp, XFS_ILOCK_EXCL);
 	xfs_iunlock(sip, XFS_ILOCK_EXCL);
+	xfs_parent_finish(mp, parent);
 	return error;
 
  error_return:
 	xfs_trans_cancel(tp);
 	xfs_iunlock(tdp, XFS_ILOCK_EXCL);
 	xfs_iunlock(sip, XFS_ILOCK_EXCL);
+ out_parent:
+	xfs_parent_finish(mp, parent);
  std_return:
 	if (error == -ENOSPC && nospace_error)
 		error = nospace_error;