[PATCH v8 20/28] xfs: parent pointer attribute creation

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

From: Dave Chinner <dchinner@redhat.com>

Add parent pointer attribute during xfs_create, and
subroutines to initialize attributes

[bfoster: rebase, use VFS inode generation]
[achender: rebased, changed __unint32_t to xfs_dir2_dataptr_t,
	   fixed some null pointer bugs,
	   merged error handling patch,
	   added subroutines to handle attribute initialization,
	   remove unnecessary ENOSPC handling in xfs_attr_set_first_parent]

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
---
 fs/xfs/Makefile            |   2 +
 fs/xfs/libxfs/xfs_parent.c | 101 +++++++++++++++++++++++++++++++++++++++++++++
 fs/xfs/libxfs/xfs_parent.h |  35 ++++++++++++++++
 fs/xfs/xfs_inode.c         |  17 +++++++-
 fs/xfs/xfs_parent_utils.c  |  52 +++++++++++++++++++++++
 fs/xfs/xfs_parent_utils.h  |  26 ++++++++++++
 6 files changed, 231 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index 022e0b4..45a3360 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -42,6 +42,7 @@ xfs-y				+= $(addprefix libxfs/, \
 				   xfs_inode_fork.o \
 				   xfs_inode_buf.o \
 				   xfs_log_rlimit.o \
+				   xfs_parent.o \
 				   xfs_ag_resv.o \
 				   xfs_rmap.o \
 				   xfs_rmap_btree.o \
@@ -82,6 +83,7 @@ xfs-y				+= xfs_aops.o \
 				   xfs_message.o \
 				   xfs_mount.o \
 				   xfs_mru_cache.o \
+				   xfs_parent_utils.o \
 				   xfs_reflink.o \
 				   xfs_stats.o \
 				   xfs_super.o \
diff --git a/fs/xfs/libxfs/xfs_parent.c b/fs/xfs/libxfs/xfs_parent.c
new file mode 100644
index 0000000..5045f65
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_parent.c
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2015 Red Hat, Inc.
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_format.h"
+#include "xfs_da_format.h"
+#include "xfs_log_format.h"
+#include "xfs_shared.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_inode.h"
+#include "xfs_error.h"
+#include "xfs_trace.h"
+#include "xfs_trans.h"
+#include "xfs_da_btree.h"
+#include "xfs_attr.h"
+#include "xfs_da_btree.h"
+#include "xfs_attr_sf.h"
+#include "xfs_bmap.h"
+
+/*
+ * Parent pointer attribute handling.
+ *
+ * Because the attribute value is a filename component, it will never be longer
+ * than 255 bytes. This means the attribute will always be a local format
+ * attribute as it is xfs_attr_leaf_entsize_local_max() for v5 filesystems will
+ * always be larger than this (max is 75% of block size).
+ *
+ * Creating a new parent attribute will always create a new attribute - there
+ * should never, ever be an existing attribute in the tree for a new inode.
+ * ENOSPC behaviour is problematic - creating the inode without the parent
+ * pointer is effectively a corruption, so we allow parent attribute creation
+ * to dip into the reserve block pool to avoid unexpected ENOSPC errors from
+ * occurring.
+ */
+
+
+/* Initializes a xfs_parent_name_rec to be stored as an attribute name */
+void
+xfs_init_parent_name_rec(
+	struct xfs_parent_name_rec	*rec,
+	struct xfs_inode		*ip,
+	uint32_t			p_diroffset)
+{
+	xfs_ino_t			p_ino = ip->i_ino;
+	uint32_t			p_gen = VFS_I(ip)->i_generation;
+
+	rec->p_ino = cpu_to_be64(p_ino);
+	rec->p_gen = cpu_to_be32(p_gen);
+	rec->p_diroffset = cpu_to_be32(p_diroffset);
+}
+
+/* Initializes a xfs_parent_name_irec from an xfs_parent_name_rec */
+void
+xfs_init_parent_name_irec(
+	struct xfs_parent_name_irec	*irec,
+	struct xfs_parent_name_rec	*rec)
+{
+	irec->p_ino = be64_to_cpu(rec->p_ino);
+	irec->p_gen = be32_to_cpu(rec->p_gen);
+	irec->p_diroffset = be32_to_cpu(rec->p_diroffset);
+}
+
+/*
+ * Directly add a parent pointer instead of as a deferred operation
+ * Currently only used during protofile creation
+ */
+int
+xfs_parent_add(
+	struct xfs_inode		*parent,
+	struct xfs_inode		*child,
+	struct xfs_name			*child_name,
+	uint32_t			diroffset)
+{
+	struct xfs_parent_name_rec	rec;
+	int				error;
+	int				flags = ATTR_PARENT;
+
+	xfs_init_parent_name_rec(&rec, parent, diroffset);
+
+	error = xfs_attr_set(child, (const unsigned char *)&rec, sizeof(rec), 
+		(char *)child_name->name, child_name->len, flags);
+
+	return error;
+}
+
diff --git a/fs/xfs/libxfs/xfs_parent.h b/fs/xfs/libxfs/xfs_parent.h
new file mode 100644
index 0000000..60f1172
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_parent.h
@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2018 Oracle, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation Inc.
+ */
+#ifndef	__XFS_PARENT_H__
+#define	__XFS_PARENT_H__
+
+#include "xfs_da_format.h"
+#include "xfs_format.h"
+
+/*
+ * Parent pointer attribute prototypes
+ */
+void xfs_init_parent_name_rec(struct xfs_parent_name_rec *rec,
+			      struct xfs_inode *ip,
+			      uint32_t p_diroffset);
+void xfs_init_parent_name_irec(struct xfs_parent_name_irec *irec,
+			       struct xfs_parent_name_rec *rec);
+
+int xfs_parent_add(struct xfs_inode *parent,
+		   struct xfs_inode *child, struct xfs_name *child_name,
+		   uint32_t diroffset);
+#endif	/* __XFS_PARENT_H__ */
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index d7e06c2..3f722e6 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -41,6 +41,7 @@
 #include "xfs_bmap_btree.h"
 #include "xfs_reflink.h"
 #include "xfs_dir2_priv.h"
+#include "xfs_parent_utils.h"
 
 kmem_zone_t *xfs_inode_zone;
 
@@ -1151,6 +1152,7 @@ xfs_create(
 	struct xfs_dquot	*pdqp = NULL;
 	struct xfs_trans_res	*tres;
 	uint			resblks;
+	xfs_dir2_dataptr_t	diroffset;
 
 	trace_xfs_create(dp, name);
 
@@ -1219,13 +1221,13 @@ xfs_create(
 	 * the transaction cancel unlocking dp so don't do it explicitly in the
 	 * error path.
 	 */
-	xfs_trans_ijoin(tp, dp, XFS_ILOCK_EXCL);
+	xfs_trans_ijoin(tp, dp, 0);
 	unlock_dp_on_error = false;
 
 	error = xfs_dir_createname(tp, dp, name, ip->i_ino,
 				   resblks ?
 					resblks - XFS_IALLOC_SPACE_RES(mp) : 0,
-					NULL);
+					&diroffset);
 	if (error) {
 		ASSERT(error != -ENOSPC);
 		goto out_trans_cancel;
@@ -1244,6 +1246,16 @@ xfs_create(
 	}
 
 	/*
+	 * If we have parent pointers, we need to add the attribute containing
+	 * the parent information now.
+	 */
+	if (xfs_sb_version_hasparent(&mp->m_sb)) {
+		error = xfs_parent_add_deferred(dp, tp, ip, name, diroffset);
+		if (error)
+			goto out_trans_cancel;
+	}
+
+	/*
 	 * If this is a synchronous mount, make sure that the
 	 * create transaction goes to disk before returning to
 	 * the user.
@@ -1268,6 +1280,7 @@ xfs_create(
 
 	*ipp = ip;
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	xfs_iunlock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
 	return 0;
 
  out_trans_cancel:
diff --git a/fs/xfs/xfs_parent_utils.c b/fs/xfs/xfs_parent_utils.c
new file mode 100644
index 0000000..f84a4fd
--- /dev/null
+++ b/fs/xfs/xfs_parent_utils.c
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2015 Red Hat, Inc.
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_shared.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_inode.h"
+#include "xfs_error.h"
+#include "xfs_trace.h"
+#include "xfs_trans.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
+#include "xfs_attr.h"
+#include "xfs_parent.h"
+
+/*
+ * Add a parent record to an inode with existing parent records.
+ */
+int
+xfs_parent_add_deferred(
+	struct xfs_inode        *parent,
+	struct xfs_trans	*tp,
+	struct xfs_inode        *child,
+	struct xfs_name         *child_name,
+	uint32_t                diroffset)
+{
+	struct xfs_parent_name_rec rec;
+
+	xfs_init_parent_name_rec(&rec, parent, diroffset);
+
+	return xfs_attr_set_deferred(child, tp, &rec, sizeof(rec),
+		(void *)child_name->name, child_name->len, ATTR_PARENT);
+}
+
diff --git a/fs/xfs/xfs_parent_utils.h b/fs/xfs/xfs_parent_utils.h
new file mode 100644
index 0000000..82453d2
--- /dev/null
+++ b/fs/xfs/xfs_parent_utils.h
@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2017 Oracle, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation Inc.
+ */
+#ifndef	__XFS_PARENT_UTILS_H__
+#define	__XFS_PARENT_UTILS_H__
+
+/*
+ * Parent pointer attribute prototypes
+ */
+int xfs_parent_add_deferred(struct xfs_inode *parent, struct xfs_trans *tp,
+	       struct xfs_inode *child, struct xfs_name *child_name,
+	       uint32_t diroffset);
+#endif	/* __XFS_PARENT_UTILS_H__ */
-- 
2.7.4