[PATCH v2 12/18] xfs: parent pointer attribute creation

[Allison Henderson <allison.henderson@oracle.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,
           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            |   1 +
 fs/xfs/libxfs/xfs_attr.c   |   4 +-
 fs/xfs/libxfs/xfs_attr.h   |   4 +-
 fs/xfs/libxfs/xfs_parent.c | 134 +++++++++++++++++++++++++++++++++++++
 fs/xfs/libxfs/xfs_parent.h |  34 ++++++++++
 fs/xfs/xfs_inode.c         |  37 ++++++++--
 fs/xfs/xfs_xattr.c         |   2 +-
 fs/xfs/xfs_xattr.h         |   1 +
 8 files changed, 208 insertions(+), 9 deletions(-)

diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index 1131dd01e4fe..caeea8d968ba 100644
--- a/fs/xfs/Makefile
+++ b/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 \
diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 2ef3262f21e8..0a458ea7051f 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -880,7 +880,7 @@ xfs_attr_lookup(
 	return error;
 }
 
-static int
+int
 xfs_attr_intent_init(
 	struct xfs_da_args	*args,
 	unsigned int		op_flags,	/* op flag (set or remove) */
@@ -898,7 +898,7 @@ xfs_attr_intent_init(
 }
 
 /* Sets an attribute for an inode as a deferred operation */
-static int
+int
 xfs_attr_defer_add(
 	struct xfs_da_args	*args)
 {
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index af92cc57e7d8..b47417b5172f 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -544,6 +544,7 @@ int xfs_inode_hasattr(struct xfs_inode *ip);
 bool xfs_attr_is_leaf(struct xfs_inode *ip);
 int xfs_attr_get_ilocked(struct xfs_da_args *args);
 int xfs_attr_get(struct xfs_da_args *args);
+int xfs_attr_defer_add(struct xfs_da_args *args);
 int xfs_attr_set(struct xfs_da_args *args);
 int xfs_attr_set_iter(struct xfs_attr_intent *attr);
 int xfs_attr_remove_iter(struct xfs_attr_intent *attr);
@@ -552,7 +553,8 @@ bool xfs_attr_namecheck(struct xfs_mount *mp, const void *name, size_t length,
 int xfs_attr_calc_size(struct xfs_da_args *args, int *local);
 void xfs_init_attr_trans(struct xfs_da_args *args, struct xfs_trans_res *tres,
 			 unsigned int *total);
-
+int xfs_attr_intent_init(struct xfs_da_args *args, unsigned int op_flags,
+			 struct xfs_attr_intent  **attr);
 /*
  * Check to see if the attr should be upgraded from non-existent or shortform to
  * single-leaf-block attribute list.
diff --git a/fs/xfs/libxfs/xfs_parent.c b/fs/xfs/libxfs/xfs_parent.c
new file mode 100644
index 000000000000..4ab531c77d7d
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_parent.c
@@ -0,0 +1,134 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022 Oracle, Inc.
+ * All rights reserved.
+ */
+#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"
+#include "xfs_defer.h"
+#include "xfs_log.h"
+#include "xfs_xattr.h"
+#include "xfs_parent.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);
+}
+
+int
+xfs_parent_init(
+	xfs_mount_t                     *mp,
+	xfs_inode_t			*ip,
+	struct xfs_name			*target_name,
+	struct xfs_parent_defer		**parentp)
+{
+	struct xfs_parent_defer		*parent;
+	int				error;
+
+	if (!xfs_has_parent(mp))
+		return 0;
+
+	error = xfs_attr_grab_log_assist(mp);
+	if (error)
+		return error;
+
+	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
+	if (!parent)
+		return -ENOMEM;
+
+	/* init parent da_args */
+	parent->args.dp = ip;
+	parent->args.geo = mp->m_attr_geo;
+	parent->args.whichfork = XFS_ATTR_FORK;
+	parent->args.attr_filter = XFS_ATTR_PARENT;
+	parent->args.op_flags = XFS_DA_OP_OKNOENT | XFS_DA_OP_LOGGED;
+	parent->args.name = (const uint8_t *)&parent->rec;
+	parent->args.namelen = sizeof(struct xfs_parent_name_rec);
+
+	if (target_name) {
+		parent->args.value = (void *)target_name->name;
+		parent->args.valuelen = target_name->len;
+	}
+
+	*parentp = parent;
+	return 0;
+}
+
+int
+xfs_parent_defer_add(
+	struct xfs_trans	*tp,
+	struct xfs_inode	*ip,
+	struct xfs_parent_defer	*parent,
+	xfs_dir2_dataptr_t	diroffset)
+{
+	struct xfs_da_args	*args = &parent->args;
+
+	xfs_init_parent_name_rec(&parent->rec, ip, diroffset);
+	args->trans = tp;
+	args->hashval = xfs_da_hashname(args->name, args->namelen);
+	return xfs_attr_defer_add(args);
+}
+
+void
+xfs_parent_cancel(
+	xfs_mount_t		*mp,
+	struct xfs_parent_defer *parent)
+{
+	xlog_drop_incompat_feat(mp->m_log);
+	kfree(parent);
+}
+
diff --git a/fs/xfs/libxfs/xfs_parent.h b/fs/xfs/libxfs/xfs_parent.h
new file mode 100644
index 000000000000..21a350b97ed5
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_parent.h
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022 Oracle, Inc.
+ * All Rights Reserved.
+ */
+#ifndef	__XFS_PARENT_H__
+#define	__XFS_PARENT_H__
+
+/*
+ * Dynamically allocd structure used to wrap the needed data to pass around
+ * the defer ops machinery
+ */
+struct xfs_parent_defer {
+	struct xfs_parent_name_rec	rec;
+	struct xfs_da_args		args;
+};
+
+/*
+ * 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_init(xfs_mount_t *mp, xfs_inode_t *ip,
+		    struct xfs_name *target_name,
+		    struct xfs_parent_defer **parentp);
+int xfs_parent_defer_add(struct xfs_trans *tp, struct xfs_inode *ip,
+			 struct xfs_parent_defer *parent,
+			 xfs_dir2_dataptr_t diroffset);
+void xfs_parent_cancel(xfs_mount_t *mp, struct xfs_parent_defer *parent);
+
+#endif	/* __XFS_PARENT_H__ */
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 09876ba10a42..ef993c3a8963 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -37,6 +37,8 @@
 #include "xfs_reflink.h"
 #include "xfs_ag.h"
 #include "xfs_log_priv.h"
+#include "xfs_parent.h"
+#include "xfs_xattr.h"
 
 struct kmem_cache *xfs_inode_cache;
 
@@ -950,7 +952,7 @@ xfs_bumplink(
 int
 xfs_create(
 	struct user_namespace	*mnt_userns,
-	xfs_inode_t		*dp,
+	struct xfs_inode	*dp,
 	struct xfs_name		*name,
 	umode_t			mode,
 	dev_t			rdev,
@@ -962,7 +964,7 @@ xfs_create(
 	struct xfs_inode	*ip = NULL;
 	struct xfs_trans	*tp = NULL;
 	int			error;
-	bool                    unlock_dp_on_error = false;
+	bool			unlock_dp_on_error = false;
 	prid_t			prid;
 	struct xfs_dquot	*udqp = NULL;
 	struct xfs_dquot	*gdqp = NULL;
@@ -970,6 +972,8 @@ xfs_create(
 	struct xfs_trans_res	*tres;
 	uint			resblks;
 	xfs_ino_t		ino;
+	xfs_dir2_dataptr_t	diroffset;
+	struct xfs_parent_defer	*parent = NULL;
 
 	trace_xfs_create(dp, name);
 
@@ -996,6 +1000,12 @@ xfs_create(
 		tres = &M_RES(mp)->tr_create;
 	}
 
+	if (xfs_has_parent(mp)) {
+		error = xfs_parent_init(mp, dp, name, &parent);
+		if (error)
+			goto out_release_dquots;
+	}
+
 	/*
 	 * Initially assume that the file does not exist and
 	 * reserve the resources for that case.  If that is not
@@ -1011,7 +1021,7 @@ xfs_create(
 				resblks, &tp);
 	}
 	if (error)
-		goto out_release_dquots;
+		goto drop_incompat;
 
 	xfs_ilock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
 	unlock_dp_on_error = true;
@@ -1021,6 +1031,7 @@ xfs_create(
 	 * entry pointing to them, but a directory also the "." entry
 	 * pointing to itself.
 	 */
+	init_xattrs |= xfs_has_parent(mp);
 	error = xfs_dialloc(&tp, dp->i_ino, mode, &ino);
 	if (!error)
 		error = xfs_init_new_inode(mnt_userns, tp, dp, ino, mode,
@@ -1035,11 +1046,12 @@ 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;
@@ -1055,6 +1067,17 @@ xfs_create(
 		xfs_bumplink(tp, dp);
 	}
 
+	/*
+	 * If we have parent pointers, we need to add the attribute containing
+	 * the parent information now.
+	 */
+	if (parent) {
+		parent->args.dp	= ip;
+		error = xfs_parent_defer_add(tp, dp, parent, 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
@@ -1080,6 +1103,7 @@ xfs_create(
 
 	*ipp = ip;
 	xfs_iunlock(ip, XFS_ILOCK_EXCL);
+	xfs_iunlock(dp, XFS_ILOCK_EXCL | XFS_ILOCK_PARENT);
 	return 0;
 
  out_trans_cancel:
@@ -1094,6 +1118,9 @@ xfs_create(
 		xfs_finish_inode_setup(ip);
 		xfs_irele(ip);
 	}
+ drop_incompat:
+	if (parent)
+		xfs_parent_cancel(mp, parent);
  out_release_dquots:
 	xfs_qm_dqrele(udqp);
 	xfs_qm_dqrele(gdqp);
diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
index c325a28b89a8..d9067c5f6bd6 100644
--- a/fs/xfs/xfs_xattr.c
+++ b/fs/xfs/xfs_xattr.c
@@ -27,7 +27,7 @@
  * they must release the permission by calling xlog_drop_incompat_feat
  * when they're done.
  */
-static inline int
+int
 xfs_attr_grab_log_assist(
 	struct xfs_mount	*mp)
 {
diff --git a/fs/xfs/xfs_xattr.h b/fs/xfs/xfs_xattr.h
index 2b09133b1b9b..3fd6520a4d69 100644
--- a/fs/xfs/xfs_xattr.h
+++ b/fs/xfs/xfs_xattr.h
@@ -7,6 +7,7 @@
 #define __XFS_XATTR_H__
 
 int xfs_attr_change(struct xfs_da_args *args);
+int xfs_attr_grab_log_assist(struct xfs_mount *mp);
 
 extern const struct xattr_handler *xfs_xattr_handlers[];
 
-- 
2.25.1