lvm2/lib/writecache/writecache.c

/*
 * Copyright (C) 2013-2016 Red Hat, Inc. All rights reserved.
 *
 * This file is part of LVM2.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU Lesser General Public License v.2.1.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "base/memory/zalloc.h"
#include "lib/misc/lib.h"
#include "lib/commands/toolcontext.h"
#include "lib/metadata/segtype.h"
#include "lib/display/display.h"
#include "lib/format_text/text_export.h"
#include "lib/config/config.h"
#include "lib/datastruct/str_list.h"
#include "lib/misc/lvm-string.h"
#include "lib/activate/activate.h"
#include "lib/metadata/metadata.h"
#include "lib/metadata/lv_alloc.h"
#include "lib/config/defaults.h"

static int _writecache_cleaner_supported;
static int _writecache_max_age_supported;

#define SEG_LOG_ERROR(t, p...) \
        log_error(t " segment %s of logical volume %s.", ## p,	\
                  dm_config_parent_name(sn), seg->lv->name), 0;

static void _writecache_display(const struct lv_segment *seg)
{
	/* TODO: lvdisplay segments */
}

static int _writecache_text_import(struct lv_segment *seg,
				   const struct dm_config_node *sn,
				   struct dm_hash_table *pv_hash __attribute__((unused)))
{
	struct logical_volume *origin_lv = NULL;
	struct logical_volume *fast_lv;
	const char *origin_name = NULL;
	const char *fast_name = NULL;

	if (!dm_config_has_node(sn, "origin"))
		return SEG_LOG_ERROR("origin not specified in");

	if (!dm_config_get_str(sn, "origin", &origin_name))
		return SEG_LOG_ERROR("origin must be a string in");

	if (!(origin_lv = find_lv(seg->lv->vg, origin_name)))
		return SEG_LOG_ERROR("Unknown LV specified for writecache origin %s in", origin_name);

	if (!set_lv_segment_area_lv(seg, 0, origin_lv, 0, 0))
		return_0;

	if (!dm_config_has_node(sn, "writecache"))
		return SEG_LOG_ERROR("writecache not specified in");

	if (!dm_config_get_str(sn, "writecache", &fast_name))
		return SEG_LOG_ERROR("writecache must be a string in");

	if (!(fast_lv = find_lv(seg->lv->vg, fast_name)))
		return SEG_LOG_ERROR("Unknown logical volume %s specified for writecache in",
				     fast_name);

	if (!dm_config_get_uint32(sn, "writecache_block_size", &seg->writecache_block_size))
		return SEG_LOG_ERROR("writecache block_size must be set in");

	seg->origin = origin_lv;
	seg->writecache = fast_lv;
	seg->lv->status |= WRITECACHE;

	if (!add_seg_to_segs_using_this_lv(fast_lv, seg))
		return_0;

	memset(&seg->writecache_settings, 0, sizeof(struct writecache_settings));

	if (dm_config_has_node(sn, "high_watermark")) {
		if (!dm_config_get_uint64(sn, "high_watermark", &seg->writecache_settings.high_watermark))
			return SEG_LOG_ERROR("Unknown writecache_setting in");
		seg->writecache_settings.high_watermark_set = 1;
	}

	if (dm_config_has_node(sn, "low_watermark")) {
		if (!dm_config_get_uint64(sn, "low_watermark", &seg->writecache_settings.low_watermark))
			return SEG_LOG_ERROR("Unknown writecache_setting in");
		seg->writecache_settings.low_watermark_set = 1;
	}

	if (dm_config_has_node(sn, "writeback_jobs")) {
		if (!dm_config_get_uint64(sn, "writeback_jobs", &seg->writecache_settings.writeback_jobs))
			return SEG_LOG_ERROR("Unknown writecache_setting in");
		seg->writecache_settings.writeback_jobs_set = 1;
	}

	if (dm_config_has_node(sn, "autocommit_blocks")) {
		if (!dm_config_get_uint64(sn, "autocommit_blocks", &seg->writecache_settings.autocommit_blocks))
			return SEG_LOG_ERROR("Unknown writecache_setting in");
		seg->writecache_settings.autocommit_blocks_set = 1;
	}

	if (dm_config_has_node(sn, "autocommit_time")) {
		if (!dm_config_get_uint64(sn, "autocommit_time", &seg->writecache_settings.autocommit_time))
			return SEG_LOG_ERROR("Unknown writecache_setting in");
		seg->writecache_settings.autocommit_time_set = 1;
	}

	if (dm_config_has_node(sn, "fua")) {
		if (!dm_config_get_uint32(sn, "fua", &seg->writecache_settings.fua))
			return SEG_LOG_ERROR("Unknown writecache_setting in");
		seg->writecache_settings.fua_set = 1;
	}

	if (dm_config_has_node(sn, "nofua")) {
		if (!dm_config_get_uint32(sn, "nofua", &seg->writecache_settings.nofua))
			return SEG_LOG_ERROR("Unknown writecache_setting in");
		seg->writecache_settings.nofua_set = 1;
	}

	if (dm_config_has_node(sn, "cleaner")) {
		if (!dm_config_get_uint32(sn, "cleaner", &seg->writecache_settings.cleaner))
			return SEG_LOG_ERROR("Unknown writecache_setting in");
		seg->writecache_settings.cleaner_set = 1;
	}

	if (dm_config_has_node(sn, "max_age")) {
		if (!dm_config_get_uint32(sn, "max_age", &seg->writecache_settings.max_age))
			return SEG_LOG_ERROR("Unknown writecache_setting in");
		seg->writecache_settings.max_age_set = 1;
	}

	if (dm_config_has_node(sn, "writecache_setting_key")) {
		const char *key;
		const char *val;

		if (!dm_config_get_str(sn, "writecache_setting_key", &key))
			return SEG_LOG_ERROR("Unknown writecache_setting in");
		if (!dm_config_get_str(sn, "writecache_setting_val", &val))
			return SEG_LOG_ERROR("Unknown writecache_setting in");

		seg->writecache_settings.new_key = dm_pool_strdup(seg->lv->vg->vgmem, key);
		seg->writecache_settings.new_val = dm_pool_strdup(seg->lv->vg->vgmem, val);
	}

	return 1;
}

static int _writecache_text_import_area_count(const struct dm_config_node *sn,
					      uint32_t *area_count)
{
	*area_count = 1;

	return 1;
}

static int _writecache_text_export(const struct lv_segment *seg,
				   struct formatter *f)
{
	outf(f, "writecache = \"%s\"", seg->writecache->name);
	outf(f, "origin = \"%s\"", seg_lv(seg, 0)->name);
	outf(f, "writecache_block_size = %u", seg->writecache_block_size);

	if (seg->writecache_settings.high_watermark_set) {
	        outf(f, "high_watermark = %llu",
	                (unsigned long long)seg->writecache_settings.high_watermark);
	}

	if (seg->writecache_settings.low_watermark_set) {
	        outf(f, "low_watermark = %llu",
	                (unsigned long long)seg->writecache_settings.low_watermark);
	}

	if (seg->writecache_settings.writeback_jobs_set) {
	        outf(f, "writeback_jobs = %llu",
	                (unsigned long long)seg->writecache_settings.writeback_jobs);
	}

	if (seg->writecache_settings.autocommit_blocks_set) {
	        outf(f, "autocommit_blocks = %llu",
	                (unsigned long long)seg->writecache_settings.autocommit_blocks);
	}

	if (seg->writecache_settings.autocommit_time_set) {
	        outf(f, "autocommit_time = %llu",
	                (unsigned long long)seg->writecache_settings.autocommit_time);
	}

	if (seg->writecache_settings.fua_set) {
	        outf(f, "fua = %u", seg->writecache_settings.fua);
	}

	if (seg->writecache_settings.nofua_set) {
	        outf(f, "nofua = %u", seg->writecache_settings.nofua);
	}

	if (seg->writecache_settings.cleaner_set && seg->writecache_settings.cleaner) {
	        outf(f, "cleaner = %u", seg->writecache_settings.cleaner);
	}

	if (seg->writecache_settings.max_age_set) {
	        outf(f, "max_age = %u", seg->writecache_settings.max_age);
	}

	if (seg->writecache_settings.new_key && seg->writecache_settings.new_val) {
	        outf(f, "writecache_setting_key = \"%s\"",
	                seg->writecache_settings.new_key);

	        outf(f, "writecache_setting_val = \"%s\"",
	                seg->writecache_settings.new_val);
	}

	return 1;
}

static void _destroy(struct segment_type *segtype)
{
	free((void *) segtype);
}

#ifdef DEVMAPPER_SUPPORT

static int _target_present(struct cmd_context *cmd,
			   const struct lv_segment *seg __attribute__((unused)),
			   unsigned *attributes __attribute__((unused)))
{
	static int _writecache_checked = 0;
	static int _writecache_present = 0;
	uint32_t maj, min, patchlevel;

	if (!activation())
		return 0;

	if (!_writecache_checked) {
		_writecache_checked = 1;
		_writecache_present = target_present(cmd, TARGET_NAME_WRITECACHE, 1);

		if (!_writecache_present) {
			log_error("dm-writecache module not found in kernel.");
			return 0;
		}

		if (!target_version(TARGET_NAME_WRITECACHE, &maj, &min, &patchlevel)) {
			log_error("dm-writecache module version not found.");
			return_0;
		}

		if (maj < 1) {
			log_error("dm-writecache module version older than minimum 1.0.0");
			return 0;
		}

		if (min >= 2) {
			_writecache_cleaner_supported = 1;
			_writecache_max_age_supported = 1;
		}
	}

	return _writecache_present;
}

bool writecache_cleaner_supported(struct cmd_context *cmd)
{
	_target_present(cmd, NULL, NULL);
	return _writecache_cleaner_supported ? true : false;
}

static int _modules_needed(struct dm_pool *mem,
			   const struct lv_segment *seg __attribute__((unused)),
			   struct dm_list *modules)
{
	if (!str_list_add(mem, modules, MODULE_NAME_WRITECACHE)) {
		log_error("String list allocation failed for writecache module.");
		return 0;
	}

	return 1;
}

#else
bool writecache_cleaner_supported(struct cmd_context *cmd)
{
	return 0;
}
#endif /* DEVMAPPER_SUPPORT */

#ifdef DEVMAPPER_SUPPORT
static int _writecache_add_target_line(struct dev_manager *dm,
				 struct dm_pool *mem,
				 struct cmd_context *cmd __attribute__((unused)),
				 void **target_state __attribute__((unused)),
				 struct lv_segment *seg,
				 const struct lv_activate_opts *laopts __attribute__((unused)),
				 struct dm_tree_node *node, uint64_t len,
				 uint32_t *pvmove_mirror_count __attribute__((unused)))
{
	char *origin_uuid;
	char *fast_uuid;
	int pmem;

	if (!seg_is_writecache(seg)) {
		log_error(INTERNAL_ERROR "Passed segment is not writecache.");
		return 0;
	}

	if (!seg->writecache) {
		log_error(INTERNAL_ERROR "Passed segment has no writecache.");
		return 0;
	}

	if (!_writecache_cleaner_supported && seg->writecache_settings.cleaner_set && seg->writecache_settings.cleaner) {
		log_warn("WARNING: ignoring writecache setting \"cleaner\" which is not supported by kernel for LV %s.", seg->lv->name);
		seg->writecache_settings.cleaner = 0;
		seg->writecache_settings.cleaner_set = 0;
	}

	if (!_writecache_max_age_supported && seg->writecache_settings.max_age_set) {
		log_warn("WARNING: ignoring writecache setting \"max_age\" which is not supported by kernel for LV %s.", seg->lv->name);
		seg->writecache_settings.max_age = 0;
		seg->writecache_settings.max_age_set = 0;
	}

	if ((pmem = lv_on_pmem(seg->writecache)) < 0)
		return_0;

	if (!(origin_uuid = build_dm_uuid(mem, seg_lv(seg, 0), "real")))
		return_0;

	if (!(fast_uuid = build_dm_uuid(mem, seg->writecache, "cvol")))
		return_0;

	if (!dm_tree_node_add_writecache_target(node, len,
						origin_uuid, fast_uuid,
						pmem,
						seg->writecache_block_size,
						&seg->writecache_settings))
		return_0;

	return 1;
}
#endif /* DEVMAPPER_SUPPORT */

static struct segtype_handler _writecache_ops = {
	.display = _writecache_display,
	.text_import = _writecache_text_import,
	.text_import_area_count = _writecache_text_import_area_count,
	.text_export = _writecache_text_export,
#ifdef DEVMAPPER_SUPPORT
	.add_target_line = _writecache_add_target_line,
	.target_present = _target_present,
	.modules_needed = _modules_needed,
#endif
	.destroy = _destroy,
};

int init_writecache_segtypes(struct cmd_context *cmd,
			struct segtype_library *seglib)
{
	struct segment_type *segtype = zalloc(sizeof(*segtype));

	if (!segtype) {
		log_error("Failed to allocate memory for writecache segtype");
		return 0;
	}

	segtype->name = SEG_TYPE_NAME_WRITECACHE;
	segtype->flags = SEG_WRITECACHE;
	segtype->ops = &_writecache_ops;

	if (!lvm_register_segtype(seglib, segtype))
		return_0;
	log_very_verbose("Initialised segtype: %s", segtype->name);

	return 1;
}