xfs: parent pointer attribute creation

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

@@ -40,6 +40,7 @@ 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 \

fs/xfs/libxfs/xfs_attr.c

@@ -357,12 +357,25 @@ xfs_attr_set_iter(
 	struct xfs_buf			**leaf_bp = &attr->xattri_leaf_bp;
 	struct xfs_inode		*dp = args->dp;
 	struct xfs_buf			*bp = NULL;
-	int				forkoff, error = 0;
+	int				sf_size, forkoff, error = 0;
 	struct xfs_mount		*mp = args->dp->i_mount;
 
 	/* State machine switch */
 	switch (attr->xattri_dela_state) {
 	case XFS_DAS_UNINIT:
+		/*
+		 * New inodes may not have an attribute fork yet. So set the
+		 * attribute fork appropriately
+		 */
+		if (XFS_IFORK_Q((args->dp)) == 0) {
+			sf_size = sizeof(struct xfs_attr_sf_hdr) +
+				  xfs_attr_sf_entsize_byname(args->namelen,
+							     args->valuelen);
+			xfs_bmap_set_attrforkoff(args->dp, sf_size, NULL);
+			args->dp->i_afp = kmem_cache_zalloc(xfs_ifork_zone, 0);
+			args->dp->i_afp->if_format = XFS_DINODE_FMT_EXTENTS;
+		}
+
 		/*
 		 * If the fork is shortform, attempt to add the attr. If there
 		 * is no space, this converts to leaf format and returns

fs/xfs/libxfs/xfs_bmap.c

@@ -1029,7 +1029,7 @@ xfs_bmap_add_attrfork_local(
 /*
  * Set an inode attr fork offset based on the format of the data fork.
  */
-static int
+int
 xfs_bmap_set_attrforkoff(
 	struct xfs_inode	*ip,
 	int			size,

fs/xfs/libxfs/xfs_bmap.h

@@ -187,6 +187,7 @@ void	xfs_trim_extent(struct xfs_bmbt_irec *irec, xfs_fileoff_t bno,
 		xfs_filblks_t len);
 unsigned int xfs_bmap_compute_attr_offset(struct xfs_mount *mp);
 int	xfs_bmap_add_attrfork(struct xfs_inode *ip, int size, int rsvd);
+int	xfs_bmap_set_attrforkoff(struct xfs_inode *ip, int size, int *version);
 void	xfs_bmap_local_to_extents_empty(struct xfs_trans *tp,
 		struct xfs_inode *ip, int whichfork);
 void	__xfs_bmap_add_free(struct xfs_trans *tp, xfs_fsblock_t bno,

fs/xfs/libxfs/xfs_parent.c

@@ -0,0 +1,77 @@
+/*
+ * 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 behavior 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);
+}

fs/xfs/libxfs/xfs_parent.h

@@ -0,0 +1,31 @@
+/*
+ * 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);
+#endif	/* __XFS_PARENT_H__ */

fs/xfs/xfs_inode.c

@@ -35,6 +35,7 @@
 #include "xfs_bmap_btree.h"
 #include "xfs_reflink.h"
 #include "xfs_ag.h"
+#include "xfs_parent.h"
 
 kmem_zone_t *xfs_inode_zone;
 
@@ -954,27 +955,40 @@ xfs_bumplink(
 
 int
 xfs_create(
-	struct user_namespace	*mnt_userns,
-	xfs_inode_t		*dp,
-	struct xfs_name		*name,
-	umode_t			mode,
-	dev_t			rdev,
-	bool			init_xattrs,
-	xfs_inode_t		**ipp)
+	struct user_namespace		*mnt_userns,
+	xfs_inode_t			*dp,
+	struct xfs_name			*name,
+	umode_t				mode,
+	dev_t				rdev,
+	bool				init_xattrs,
+	xfs_inode_t			**ipp)
 {
-	int			is_dir = S_ISDIR(mode);
-	struct xfs_mount	*mp = dp->i_mount;
-	struct xfs_inode	*ip = NULL;
-	struct xfs_trans	*tp = NULL;
-	int			error;
-	bool                    unlock_dp_on_error = false;
-	prid_t			prid;
-	struct xfs_dquot	*udqp = NULL;
-	struct xfs_dquot	*gdqp = NULL;
-	struct xfs_dquot	*pdqp = NULL;
-	struct xfs_trans_res	*tres;
-	uint			resblks;
-	xfs_ino_t		ino;
+	int				is_dir = S_ISDIR(mode);
+	struct xfs_mount		*mp = dp->i_mount;
+	struct xfs_inode		*ip = NULL;
+	struct xfs_trans		*tp = NULL;
+	int				error;
+	bool				unlock_dp_on_error = false;
+	prid_t				prid;
+	struct xfs_dquot		*udqp = NULL;
+	struct xfs_dquot		*gdqp = NULL;
+	struct xfs_dquot		*pdqp = NULL;
+	struct xfs_trans_res		*tres;
+	uint				resblks;
+	xfs_ino_t			ino;
+	xfs_dir2_dataptr_t		diroffset;
+	struct xfs_parent_name_rec	rec;
+	struct xfs_da_args		args = {
+		.dp		= dp,
+		.geo		= mp->m_attr_geo,
+		.whichfork	= XFS_ATTR_FORK,
+		.attr_filter	= XFS_ATTR_PARENT,
+		.op_flags	= XFS_DA_OP_OKNOENT,
+		.name		= (const uint8_t *)&rec,
+		.namelen	= sizeof(rec),
+		.value		= (void *)name->name,
+		.valuelen	= name->len,
+	};
 
 	trace_xfs_create(dp, name);
 
@@ -1045,11 +1059,12 @@ 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 - XFS_IALLOC_SPACE_RES(mp), NULL);
+				   resblks - XFS_IALLOC_SPACE_RES(mp),
+				   &diroffset);
 	if (error) {
 		ASSERT(error != -ENOSPC);
 		goto out_trans_cancel;
@@ -1065,6 +1080,20 @@ xfs_create(
 		xfs_bumplink(tp, dp);
 	}
 
+	/*
+	 * If we have parent pointers, we need to add the attribute containing
+	 * the parent information now.
+	 */
+	if (xfs_sb_version_hasparent(&mp->m_sb)) {
+		xfs_init_parent_name_rec(&rec, dp, diroffset);
+		args.dp	= ip;
+		args.trans = tp;
+		args.hashval = xfs_da_hashname(args.name, args.namelen);
+		error =  xfs_attr_set_deferred(&args);
+		if (error)
+			goto out_trans_cancel;
+	}
+
 	/*
 	 * If this is a synchronous mount, make sure that the
 	 * create transaction goes to disk before returning to
@@ -1090,6 +1119,7 @@ xfs_create(
 
 	*ipp = ip;
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	xfs_iunlock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
 	return 0;
 
  out_trans_cancel: