Add TXG timestamp database

This feature enables tracking of when TXGs are committed to disk,
providing an estimated timestamp for each TXG.

With this information, it becomes possible to perform scrubs based
on specific date ranges, improving the granularity of data
management and recovery operations.

Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <alexander.motin@TrueNAS.com>
Reviewed-by: Paul Dagnelie <paul.dagnelie@klarasystems.com>
Signed-off-by: Mariusz Zaborski <mariusz.zaborski@klarasystems.com>
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Closes #16853

include/Makefile.am

@@ -10,6 +10,7 @@ COMMON_H = \
 	cityhash.h \
 	zfeature_common.h \
 	zfs_comutil.h \
+	zfs_crrd.h \
 	zfs_deleg.h \
 	zfs_fletcher.h \
 	zfs_namecheck.h \

include/libzfs.h

@@ -302,6 +302,8 @@ typedef struct initialize_cbdata {
  * Functions to manipulate pool and vdev state
  */
 _LIBZFS_H int zpool_scan(zpool_handle_t *, pool_scan_func_t, pool_scrub_cmd_t);
+_LIBZFS_H int zpool_scan_range(zpool_handle_t *, pool_scan_func_t,
+    pool_scrub_cmd_t, time_t, time_t);
 _LIBZFS_H int zpool_initialize_one(zpool_handle_t *, void *);
 _LIBZFS_H int zpool_initialize(zpool_handle_t *, pool_initialize_func_t,
     nvlist_t *);

include/sys/dmu.h

@@ -414,6 +414,9 @@ typedef struct dmu_buf {
 #define	DMU_POOL_ZPOOL_CHECKPOINT	"com.delphix:zpool_checkpoint"
 #define	DMU_POOL_LOG_SPACEMAP_ZAP	"com.delphix:log_spacemap_zap"
 #define	DMU_POOL_DELETED_CLONES		"com.delphix:deleted_clones"
+#define	DMU_POOL_TXG_LOG_TIME_MINUTES	"com.klaraystems:txg_log_time:minutes"
+#define	DMU_POOL_TXG_LOG_TIME_DAYS	"com.klaraystems:txg_log_time:days"
+#define	DMU_POOL_TXG_LOG_TIME_MONTHS	"com.klaraystems:txg_log_time:months"
 
 /*
  * Allocate an object from this objset.  The range of object numbers

include/sys/spa_impl.h

@@ -55,6 +55,8 @@
 #include <sys/dsl_deadlist.h>
 #include <zfeature_common.h>
 
+#include "zfs_crrd.h"
+
 #ifdef	__cplusplus
 extern "C" {
 #endif
@@ -344,6 +346,12 @@ struct spa {
 	spa_checkpoint_info_t spa_checkpoint_info; /* checkpoint accounting */
 	zthr_t		*spa_checkpoint_discard_zthr;
 
+	kmutex_t	spa_txg_log_time_lock;	/* for spa_txg_log_time */
+	dbrrd_t		spa_txg_log_time;
+	uint64_t	spa_last_noted_txg;
+	uint64_t	spa_last_noted_txg_time;
+	uint64_t	spa_last_flush_txg_time;
+
 	space_map_t	*spa_syncing_log_sm;	/* current log space map */
 	avl_tree_t	spa_sm_logs_by_txg;
 	kmutex_t	spa_flushed_ms_lock;	/* for metaslabs_by_flushed */

include/zfs_crrd.h

@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: CDDL-1.0
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or https://opensource.org/licenses/CDDL-1.0.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright (c) 2024 Klara Inc.
+ *
+ * This software was developed by
+ * Mariusz Zaborski <mariusz.zaborski@klarasystems.com>
+ * Fred Weigel <fred.weigel@klarasystems.com>
+ * under sponsorship from Wasabi Technology, Inc. and Klara Inc.
+ */
+
+#ifndef _CRRD_H_
+#define	_CRRD_H_
+
+#define	RRD_MAX_ENTRIES	256
+
+#define	RRD_ENTRY_SIZE	sizeof (uint64_t)
+#define	RRD_STRUCT_ELEM	(sizeof (rrd_t) / RRD_ENTRY_SIZE)
+
+typedef enum {
+	DBRRD_FLOOR,
+	DBRRD_CEILING
+} dbrrd_rounding_t;
+
+typedef struct {
+	uint64_t	rrdd_time;
+	uint64_t	rrdd_txg;
+} rrd_data_t;
+
+typedef struct {
+	uint64_t	rrd_head;	/* head (beginning) */
+	uint64_t	rrd_tail;	/* tail (end) */
+	uint64_t	rrd_length;
+
+	rrd_data_t	rrd_entries[RRD_MAX_ENTRIES];
+} rrd_t;
+
+typedef struct {
+	rrd_t		dbr_minutes;
+	rrd_t		dbr_days;
+	rrd_t		dbr_months;
+} dbrrd_t;
+
+size_t rrd_len(rrd_t *rrd);
+
+const rrd_data_t *rrd_entry(rrd_t *r, size_t i);
+rrd_data_t *rrd_tail_entry(rrd_t *rrd);
+uint64_t rrd_tail(rrd_t *rrd);
+uint64_t rrd_get(rrd_t *rrd, size_t i);
+
+void rrd_add(rrd_t *rrd, hrtime_t time, uint64_t txg);
+
+void dbrrd_add(dbrrd_t *db, hrtime_t time, uint64_t txg);
+uint64_t dbrrd_query(dbrrd_t *r, hrtime_t tv, dbrrd_rounding_t rouding);
+
+#endif