xfs: Set up infrastructure for log attribute replay

Currently attributes are modified directly across one or more
transactions. But they are not logged or replayed in the event of an
error. The goal of log attr replay is to enable logging and replaying
of attribute operations using the existing delayed operations
infrastructure.  This will later enable the attributes to become part of
larger multi part operations that also must first be recorded to the
log.  This is mostly of interest in the scheme of parent pointers which
would need to maintain an attribute containing parent inode information
any time an inode is moved, created, or removed.  Parent pointers would
then be of interest to any feature that would need to quickly derive an
inode path from the mount point. Online scrub, nfs lookups and fs grow
or shrink operations are all features that could take advantage of this.

This patch adds two new log item types for setting or removing
attributes as deferred operations.  The xfs_attri_log_item will log an
intent to set or remove an attribute.  The corresponding
xfs_attrd_log_item holds a reference to the xfs_attri_log_item and is
freed once the transaction is done.  Both log items use a generic
xfs_attr_log_format structure that contains the attribute name, value,
flags, inode, and an op_flag that indicates if the operations is a set
or remove.

[dchinner: added extra little bits needed for intent whiteouts]

Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 458 insertions, 0 deletions

diff --git a/fs/xfs/xfs_attr_item.c b/fs/xfs/xfs_attr_item.c
new file mode 100644
index 000000000000..b1141ecaa1ab
--- /dev/null
+++ b/fs/xfs/xfs_attr_item.c
@@ -0,0 +1,458 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2022 Oracle.  All Rights Reserved.
+ * Author: Allison Henderson <allison.henderson@oracle.com>
+ */
+
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_shared.h"
+#include "xfs_mount.h"
+#include "xfs_defer.h"
+#include "xfs_log_format.h"
+#include "xfs_trans.h"
+#include "xfs_trans_priv.h"
+#include "xfs_log.h"
+#include "xfs_inode.h"
+#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
+#include "xfs_attr.h"
+#include "xfs_attr_item.h"
+#include "xfs_trace.h"
+#include "xfs_inode.h"
+#include "xfs_trans_space.h"
+#include "xfs_error.h"
+#include "xfs_log_priv.h"
+#include "xfs_log_recover.h"
+
+static const struct xfs_item_ops xfs_attri_item_ops;
+static const struct xfs_item_ops xfs_attrd_item_ops;
+
+static inline struct xfs_attri_log_item *ATTRI_ITEM(struct xfs_log_item *lip)
+{
+	return container_of(lip, struct xfs_attri_log_item, attri_item);
+}
+
+STATIC void
+xfs_attri_item_free(
+	struct xfs_attri_log_item	*attrip)
+{
+	kmem_free(attrip->attri_item.li_lv_shadow);
+	kmem_free(attrip);
+}
+
+/*
+ * Freeing the attrip requires that we remove it from the AIL if it has already
+ * been placed there. However, the ATTRI may not yet have been placed in the
+ * AIL when called by xfs_attri_release() from ATTRD processing due to the
+ * ordering of committed vs unpin operations in bulk insert operations. Hence
+ * the reference count to ensure only the last caller frees the ATTRI.
+ */
+STATIC void
+xfs_attri_release(
+	struct xfs_attri_log_item	*attrip)
+{
+	ASSERT(atomic_read(&attrip->attri_refcount) > 0);
+	if (!atomic_dec_and_test(&attrip->attri_refcount))
+		return;
+
+	xfs_trans_ail_delete(&attrip->attri_item, 0);
+	xfs_attri_item_free(attrip);
+}
+
+STATIC void
+xfs_attri_item_size(
+	struct xfs_log_item		*lip,
+	int				*nvecs,
+	int				*nbytes)
+{
+	struct xfs_attri_log_item       *attrip = ATTRI_ITEM(lip);
+
+	*nvecs += 2;
+	*nbytes += sizeof(struct xfs_attri_log_format) +
+			xlog_calc_iovec_len(attrip->attri_name_len);
+
+	if (!attrip->attri_value_len)
+		return;
+
+	*nvecs += 1;
+	*nbytes += xlog_calc_iovec_len(attrip->attri_value_len);
+}
+
+/*
+ * This is called to fill in the log iovecs for the given attri log
+ * item. We use  1 iovec for the attri_format_item, 1 for the name, and
+ * another for the value if it is present
+ */
+STATIC void
+xfs_attri_item_format(
+	struct xfs_log_item		*lip,
+	struct xfs_log_vec		*lv)
+{
+	struct xfs_attri_log_item	*attrip = ATTRI_ITEM(lip);
+	struct xfs_log_iovec		*vecp = NULL;
+
+	attrip->attri_format.alfi_type = XFS_LI_ATTRI;
+	attrip->attri_format.alfi_size = 1;
+
+	/*
+	 * This size accounting must be done before copying the attrip into the
+	 * iovec.  If we do it after, the wrong size will be recorded to the log
+	 * and we trip across assertion checks for bad region sizes later during
+	 * the log recovery.
+	 */
+
+	ASSERT(attrip->attri_name_len > 0);
+	attrip->attri_format.alfi_size++;
+
+	if (attrip->attri_value_len > 0)
+		attrip->attri_format.alfi_size++;
+
+	xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_ATTRI_FORMAT,
+			&attrip->attri_format,
+			sizeof(struct xfs_attri_log_format));
+	xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_ATTR_NAME,
+			attrip->attri_name,
+			xlog_calc_iovec_len(attrip->attri_name_len));
+	if (attrip->attri_value_len > 0)
+		xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_ATTR_VALUE,
+				attrip->attri_value,
+				xlog_calc_iovec_len(attrip->attri_value_len));
+}
+
+/*
+ * The unpin operation is the last place an ATTRI is manipulated in the log. It
+ * is either inserted in the AIL or aborted in the event of a log I/O error. In
+ * either case, the ATTRI transaction has been successfully committed to make
+ * it this far. Therefore, we expect whoever committed the ATTRI to either
+ * construct and commit the ATTRD or drop the ATTRD's reference in the event of
+ * error. Simply drop the log's ATTRI reference now that the log is done with
+ * it.
+ */
+STATIC void
+xfs_attri_item_unpin(
+	struct xfs_log_item	*lip,
+	int			remove)
+{
+	xfs_attri_release(ATTRI_ITEM(lip));
+}
+
+
+STATIC void
+xfs_attri_item_release(
+	struct xfs_log_item	*lip)
+{
+	xfs_attri_release(ATTRI_ITEM(lip));
+}
+
+/*
+ * Allocate and initialize an attri item.  Caller may allocate an additional
+ * trailing buffer for name and value
+ */
+STATIC struct xfs_attri_log_item *
+xfs_attri_init(
+	struct xfs_mount		*mp,
+	uint32_t			name_len,
+	uint32_t			value_len)
+
+{
+	struct xfs_attri_log_item	*attrip;
+	uint32_t			name_vec_len = 0;
+	uint32_t			value_vec_len = 0;
+	uint32_t			buffer_size;
+
+	if (name_len)
+		name_vec_len = xlog_calc_iovec_len(name_len);
+	if (value_len)
+		value_vec_len = xlog_calc_iovec_len(value_len);
+
+	buffer_size = name_vec_len + value_vec_len;
+
+	if (buffer_size) {
+		attrip = kmem_zalloc(sizeof(struct xfs_attri_log_item) +
+				    buffer_size, KM_NOFS);
+		if (attrip == NULL)
+			return NULL;
+	} else {
+		attrip = kmem_cache_zalloc(xfs_attri_cache,
+					  GFP_NOFS | __GFP_NOFAIL);
+	}
+
+	attrip->attri_name_len = name_len;
+	if (name_len)
+		attrip->attri_name = ((char *)attrip) +
+				sizeof(struct xfs_attri_log_item);
+	else
+		attrip->attri_name = NULL;
+
+	attrip->attri_value_len = value_len;
+	if (value_len)
+		attrip->attri_value = ((char *)attrip) +
+				sizeof(struct xfs_attri_log_item) +
+				name_vec_len;
+	else
+		attrip->attri_value = NULL;
+
+	xfs_log_item_init(mp, &attrip->attri_item, XFS_LI_ATTRI,
+			  &xfs_attri_item_ops);
+	attrip->attri_format.alfi_id = (uintptr_t)(void *)attrip;
+	atomic_set(&attrip->attri_refcount, 2);
+
+	return attrip;
+}
+
+/*
+ * Copy an attr format buffer from the given buf, and into the destination attr
+ * format structure.
+ */
+STATIC int
+xfs_attri_copy_format(
+	struct xfs_log_iovec		*buf,
+	struct xfs_attri_log_format	*dst_attr_fmt)
+{
+	struct xfs_attri_log_format	*src_attr_fmt = buf->i_addr;
+	size_t				len;
+
+	len = sizeof(struct xfs_attri_log_format);
+	if (buf->i_len != len) {
+		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, NULL);
+		return -EFSCORRUPTED;
+	}
+
+	memcpy((char *)dst_attr_fmt, (char *)src_attr_fmt, len);
+	return 0;
+}
+
+static inline struct xfs_attrd_log_item *ATTRD_ITEM(struct xfs_log_item *lip)
+{
+	return container_of(lip, struct xfs_attrd_log_item, attrd_item);
+}
+
+STATIC void
+xfs_attrd_item_free(struct xfs_attrd_log_item *attrdp)
+{
+	kmem_free(attrdp->attrd_item.li_lv_shadow);
+	kmem_free(attrdp);
+}
+
+STATIC void
+xfs_attrd_item_size(
+	struct xfs_log_item		*lip,
+	int				*nvecs,
+	int				*nbytes)
+{
+	*nvecs += 1;
+	*nbytes += sizeof(struct xfs_attrd_log_format);
+}
+
+/*
+ * This is called to fill in the log iovecs for the given attrd log item. We use
+ * only 1 iovec for the attrd_format, and we point that at the attr_log_format
+ * structure embedded in the attrd item.
+ */
+STATIC void
+xfs_attrd_item_format(
+	struct xfs_log_item	*lip,
+	struct xfs_log_vec	*lv)
+{
+	struct xfs_attrd_log_item	*attrdp = ATTRD_ITEM(lip);
+	struct xfs_log_iovec		*vecp = NULL;
+
+	attrdp->attrd_format.alfd_type = XFS_LI_ATTRD;
+	attrdp->attrd_format.alfd_size = 1;
+
+	xlog_copy_iovec(lv, &vecp, XLOG_REG_TYPE_ATTRD_FORMAT,
+			&attrdp->attrd_format,
+			sizeof(struct xfs_attrd_log_format));
+}
+
+/*
+ * The ATTRD is either committed or aborted if the transaction is canceled. If
+ * the transaction is canceled, drop our reference to the ATTRI and free the
+ * ATTRD.
+ */
+STATIC void
+xfs_attrd_item_release(
+	struct xfs_log_item		*lip)
+{
+	struct xfs_attrd_log_item	*attrdp = ATTRD_ITEM(lip);
+
+	xfs_attri_release(attrdp->attrd_attrip);
+	xfs_attrd_item_free(attrdp);
+}
+
+STATIC xfs_lsn_t
+xfs_attri_item_committed(
+	struct xfs_log_item		*lip,
+	xfs_lsn_t			lsn)
+{
+	struct xfs_attri_log_item	*attrip = ATTRI_ITEM(lip);
+
+	/*
+	 * The attrip refers to xfs_attr_item memory to log the name and value
+	 * with the intent item. This already occurred when the intent was
+	 * committed so these fields are no longer accessed. Clear them out of
+	 * caution since we're about to free the xfs_attr_item.
+	 */
+	attrip->attri_name = NULL;
+	attrip->attri_value = NULL;
+
+	/*
+	 * The ATTRI is logged only once and cannot be moved in the log, so
+	 * simply return the lsn at which it's been logged.
+	 */
+	return lsn;
+}
+
+STATIC bool
+xfs_attri_item_match(
+	struct xfs_log_item	*lip,
+	uint64_t		intent_id)
+{
+	return ATTRI_ITEM(lip)->attri_format.alfi_id == intent_id;
+}
+
+/* Is this recovered ATTRI format ok? */
+static inline bool
+xfs_attri_validate(
+	struct xfs_mount		*mp,
+	struct xfs_attri_log_format	*attrp)
+{
+	unsigned int			op = attrp->alfi_op_flags &
+					     XFS_ATTR_OP_FLAGS_TYPE_MASK;
+
+	if (attrp->__pad != 0)
+		return false;
+
+	/* alfi_op_flags should be either a set or remove */
+	if (op != XFS_ATTR_OP_FLAGS_SET && op != XFS_ATTR_OP_FLAGS_REMOVE)
+		return false;
+
+	if (attrp->alfi_value_len > XATTR_SIZE_MAX)
+		return false;
+
+	if ((attrp->alfi_name_len > XATTR_NAME_MAX) ||
+	    (attrp->alfi_name_len == 0))
+		return false;
+
+	return xfs_verify_ino(mp, attrp->alfi_ino);
+}
+
+STATIC int
+xlog_recover_attri_commit_pass2(
+	struct xlog                     *log,
+	struct list_head		*buffer_list,
+	struct xlog_recover_item        *item,
+	xfs_lsn_t                       lsn)
+{
+	int                             error;
+	struct xfs_mount                *mp = log->l_mp;
+	struct xfs_attri_log_item       *attrip;
+	struct xfs_attri_log_format     *attri_formatp;
+	int				region = 0;
+
+	attri_formatp = item->ri_buf[region].i_addr;
+
+	/* Validate xfs_attri_log_format */
+	if (!xfs_attri_validate(mp, attri_formatp)) {
+		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
+		return -EFSCORRUPTED;
+	}
+
+	/* memory alloc failure will cause replay to abort */
+	attrip = xfs_attri_init(mp, attri_formatp->alfi_name_len,
+				attri_formatp->alfi_value_len);
+	if (attrip == NULL)
+		return -ENOMEM;
+
+	error = xfs_attri_copy_format(&item->ri_buf[region],
+				      &attrip->attri_format);
+	if (error)
+		goto out;
+
+	region++;
+	memcpy(attrip->attri_name, item->ri_buf[region].i_addr,
+	       attrip->attri_name_len);
+
+	if (!xfs_attr_namecheck(attrip->attri_name, attrip->attri_name_len)) {
+		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, mp);
+		error = -EFSCORRUPTED;
+		goto out;
+	}
+
+	if (attrip->attri_value_len > 0) {
+		region++;
+		memcpy(attrip->attri_value, item->ri_buf[region].i_addr,
+		       attrip->attri_value_len);
+	}
+
+	/*
+	 * The ATTRI has two references. One for the ATTRD and one for ATTRI to
+	 * ensure it makes it into the AIL. Insert the ATTRI into the AIL
+	 * directly and drop the ATTRI reference. Note that
+	 * xfs_trans_ail_update() drops the AIL lock.
+	 */
+	xfs_trans_ail_insert(log->l_ailp, &attrip->attri_item, lsn);
+	xfs_attri_release(attrip);
+	return 0;
+out:
+	xfs_attri_item_free(attrip);
+	return error;
+}
+
+/*
+ * This routine is called when an ATTRD format structure is found in a committed
+ * transaction in the log. Its purpose is to cancel the corresponding ATTRI if
+ * it was still in the log. To do this it searches the AIL for the ATTRI with
+ * an id equal to that in the ATTRD format structure. If we find it we drop
+ * the ATTRD reference, which removes the ATTRI from the AIL and frees it.
+ */
+STATIC int
+xlog_recover_attrd_commit_pass2(
+	struct xlog			*log,
+	struct list_head		*buffer_list,
+	struct xlog_recover_item	*item,
+	xfs_lsn_t			lsn)
+{
+	struct xfs_attrd_log_format	*attrd_formatp;
+
+	attrd_formatp = item->ri_buf[0].i_addr;
+	if (item->ri_buf[0].i_len != sizeof(struct xfs_attrd_log_format)) {
+		XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, NULL);
+		return -EFSCORRUPTED;
+	}
+
+	xlog_recover_release_intent(log, XFS_LI_ATTRI,
+				    attrd_formatp->alfd_alf_id);
+	return 0;
+}
+
+static const struct xfs_item_ops xfs_attri_item_ops = {
+	.flags		= XFS_ITEM_INTENT,
+	.iop_size	= xfs_attri_item_size,
+	.iop_format	= xfs_attri_item_format,
+	.iop_unpin	= xfs_attri_item_unpin,
+	.iop_committed	= xfs_attri_item_committed,
+	.iop_release    = xfs_attri_item_release,
+	.iop_match	= xfs_attri_item_match,
+};
+
+const struct xlog_recover_item_ops xlog_attri_item_ops = {
+	.item_type	= XFS_LI_ATTRI,
+	.commit_pass2	= xlog_recover_attri_commit_pass2,
+};
+
+static const struct xfs_item_ops xfs_attrd_item_ops = {
+	.flags		= XFS_ITEM_RELEASE_WHEN_COMMITTED |
+			  XFS_ITEM_INTENT_DONE,
+	.iop_size	= xfs_attrd_item_size,
+	.iop_format	= xfs_attrd_item_format,
+	.iop_release    = xfs_attrd_item_release,
+};
+
+const struct xlog_recover_item_ops xlog_attrd_item_ops = {
+	.item_type	= XFS_LI_ATTRD,
+	.commit_pass2	= xlog_recover_attrd_commit_pass2,
+};