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lvm2/lib/metadata/cache_manip.c
Zdenek Kabelac 5d820b0201 cleanup: comment typo
2021-02-23 14:56:48 +01:00

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/*
* Copyright (C) 2014-2015 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 "lib/misc/lib.h"
#include "lib/metadata/metadata.h"
#include "lib/locking/locking.h"
#include "lib/misc/lvm-string.h"
#include "lib/commands/toolcontext.h"
#include "lib/display/display.h"
#include "lib/metadata/segtype.h"
#include "lib/activate/activate.h"
#include "lib/config/defaults.h"
#include "lib/metadata/lv_alloc.h"
#include "lib/misc/lvm-signal.h"
/* https://github.com/jthornber/thin-provisioning-tools/blob/master/caching/cache_metadata_size.cc */
#define DM_TRANSACTION_OVERHEAD 4096 /* KiB */
#define DM_BYTES_PER_BLOCK 16 /* bytes */
#define DM_HINT_OVERHEAD_PER_BLOCK 8 /* bytes */
#define DM_MAX_HINT_WIDTH (4+16) /* bytes. FIXME Configurable? */
const char *cache_mode_num_to_str(cache_mode_t mode)
{
switch (mode) {
case CACHE_MODE_WRITETHROUGH:
return "writethrough";
case CACHE_MODE_WRITEBACK:
return "writeback";
case CACHE_MODE_PASSTHROUGH:
return "passthrough";
default:
return NULL;
}
}
const char *get_cache_mode_name(const struct lv_segment *pool_seg)
{
const char *str;
if (!(str = cache_mode_num_to_str(pool_seg->cache_mode))) {
log_error(INTERNAL_ERROR "Cache pool %s has undefined cache mode, using writethrough instead.",
display_lvname(pool_seg->lv));
str = "writethrough";
}
return str;
}
const char *display_cache_mode(const struct lv_segment *seg)
{
const struct lv_segment *setting_seg = NULL;
if (seg_is_cache(seg) && lv_is_cache_vol(seg->pool_lv))
setting_seg = seg;
else if (seg_is_cache_pool(seg))
setting_seg = seg;
else if (seg_is_cache(seg))
setting_seg = first_seg(seg->pool_lv);
if (!setting_seg || (setting_seg->cache_mode == CACHE_MODE_UNSELECTED))
return "";
return cache_mode_num_to_str(setting_seg->cache_mode);
}
int set_cache_mode(cache_mode_t *mode, const char *cache_mode)
{
if (!strcasecmp(cache_mode, "writethrough"))
*mode = CACHE_MODE_WRITETHROUGH;
else if (!strcasecmp(cache_mode, "writeback"))
*mode = CACHE_MODE_WRITEBACK;
else if (!strcasecmp(cache_mode, "passthrough"))
*mode = CACHE_MODE_PASSTHROUGH;
else {
log_error("Unknown cache mode: %s.", cache_mode);
return 0;
}
return 1;
}
static cache_mode_t _get_cache_mode_from_config(struct cmd_context *cmd,
struct profile *profile,
struct logical_volume *lv)
{
cache_mode_t mode;
const char *str;
int id;
/* Figure default settings from config/profiles */
id = allocation_cache_mode_CFG;
/* If present, check backward compatible settings */
if (!find_config_node(cmd, cmd->cft, id) &&
find_config_node(cmd, cmd->cft, allocation_cache_pool_cachemode_CFG))
id = allocation_cache_pool_cachemode_CFG;
if (!(str = find_config_tree_str(cmd, id, profile))) {
log_error(INTERNAL_ERROR "Cache mode is not determined.");
return CACHE_MODE_WRITETHROUGH;
}
if (!(set_cache_mode(&mode, str)))
return CACHE_MODE_WRITETHROUGH;
return mode;
}
int cache_set_cache_mode(struct lv_segment *seg, cache_mode_t mode)
{
struct cmd_context *cmd = seg->lv->vg->cmd;
struct lv_segment *setting_seg;
/*
* Don't set a cache mode on an unused cache pool, the
* cache mode will be set when it's attached.
*/
if (seg_is_cache_pool(seg) && (mode == CACHE_MODE_UNSELECTED))
return 1;
if (seg_is_cache(seg) && lv_is_cache_vol(seg->pool_lv))
setting_seg = seg;
else if (seg_is_cache_pool(seg))
setting_seg = seg;
else if (seg_is_cache(seg))
setting_seg = first_seg(seg->pool_lv);
else {
log_error(INTERNAL_ERROR "Cannot set cache mode for non cache volume %s.",
display_lvname(seg->lv));
return 0;
}
if (mode != CACHE_MODE_UNSELECTED) {
setting_seg->cache_mode = mode;
return 1;
}
if (setting_seg->cache_mode != CACHE_MODE_UNSELECTED)
return 1;
setting_seg->cache_mode = _get_cache_mode_from_config(cmd, seg->lv->profile, seg->lv);
return 1;
}
/*
* At least warn a user if certain cache stacks may present some problems
*/
void cache_check_for_warns(const struct lv_segment *seg)
{
struct logical_volume *origin_lv = seg_lv(seg, 0);
if (lv_is_raid(origin_lv) &&
first_seg(seg->pool_lv)->cache_mode == CACHE_MODE_WRITEBACK)
log_warn("WARNING: Data redundancy could be lost with writeback "
"caching of raid logical volume!");
}
/*
* Returns the minimum size of cache metadata volume for given cache data size and
* and cache chunk size (all in/out values in sectors)
* Default metadata size is: (Overhead + mapping size + hint size)
*/
static uint64_t _cache_min_metadata_size(uint64_t data_size, uint32_t chunk_size)
{
/* Used space for mapping and hints for each cached chunk in bytes
* (matching thin-tools cache_metadata_size.cc) */
const uint64_t chunk_overhead = (DM_BYTES_PER_BLOCK + DM_MAX_HINT_WIDTH + DM_HINT_OVERHEAD_PER_BLOCK);
const uint64_t transaction_overhead = DM_TRANSACTION_OVERHEAD * 1024; /* 4MiB */
/* Number of cache chunks we have in caching volume */
uint64_t nr_chunks = data_size / chunk_size;
/* Minimal size of metadata volume converted back to sectors */
uint64_t min_meta_size = (transaction_overhead + nr_chunks * chunk_overhead +
(SECTOR_SIZE - 1)) >> SECTOR_SHIFT;
return min_meta_size;
}
int update_cache_pool_params(struct cmd_context *cmd,
struct profile *profile,
uint32_t extent_size,
const struct segment_type *segtype,
unsigned attr,
uint32_t pool_data_extents,
uint32_t *pool_metadata_extents,
struct logical_volume *metadata_lv,
int *chunk_size_calc_method, uint32_t *chunk_size)
{
uint64_t min_meta_size;
uint64_t pool_metadata_size = (uint64_t) *pool_metadata_extents * extent_size;
uint64_t pool_data_size = (uint64_t) pool_data_extents * extent_size;
const uint64_t max_chunks =
get_default_allocation_cache_pool_max_chunks_CFG(cmd, profile);
/* min chunk size in a multiple of DM_CACHE_MIN_DATA_BLOCK_SIZE */
uint64_t min_chunk_size = (((pool_data_size + max_chunks - 1) / max_chunks +
DM_CACHE_MIN_DATA_BLOCK_SIZE - 1) /
DM_CACHE_MIN_DATA_BLOCK_SIZE) * DM_CACHE_MIN_DATA_BLOCK_SIZE;
if (!*chunk_size) {
if (!(*chunk_size = find_config_tree_int(cmd, allocation_cache_pool_chunk_size_CFG,
profile) * 2)) {
*chunk_size = get_default_allocation_cache_pool_chunk_size_CFG(cmd,
profile);
/* Use power-of-2 for min chunk size when unspecified */
min_chunk_size = UINT64_C(1) << (32 - clz(min_chunk_size - 1));
}
if (*chunk_size < min_chunk_size) {
/*
* When using more then 'standard' default,
* keep user informed he might be using things in untintended direction
*/
log_print_unless_silent("Using %s chunk size instead of default %s, "
"so cache pool has less than " FMTu64 " chunks.",
display_size(cmd, min_chunk_size),
display_size(cmd, *chunk_size),
max_chunks);
*chunk_size = min_chunk_size;
} else
log_verbose("Setting chunk size to %s.",
display_size(cmd, *chunk_size));
} else if (*chunk_size < min_chunk_size) {
log_error("Chunk size %s is less than required minimal chunk size %s "
"for a cache pool of %s size and limit " FMTu64 " chunks.",
display_size(cmd, *chunk_size),
display_size(cmd, min_chunk_size),
display_size(cmd, pool_data_size),
max_chunks);
log_error("To allow use of more chunks, see setting allocation/cache_pool_max_chunks.");
return 0;
}
if (!validate_cache_chunk_size(cmd, *chunk_size))
return_0;
if ((uint64_t) *chunk_size > (uint64_t) pool_data_extents * extent_size) {
log_error("Size of %s data volume cannot be smaller than chunk size %s.",
segtype->name, display_size(cmd, *chunk_size));
return 0;
}
min_meta_size = _cache_min_metadata_size((uint64_t) pool_data_extents * extent_size, *chunk_size);
min_meta_size = dm_round_up(min_meta_size, extent_size);
if (!pool_metadata_size)
pool_metadata_size = min_meta_size;
if (!update_pool_metadata_min_max(cmd, extent_size,
min_meta_size,
(2 * DEFAULT_CACHE_POOL_MAX_METADATA_SIZE),
&pool_metadata_size,
metadata_lv,
pool_metadata_extents))
return_0;
log_verbose("Preferred pool metadata size %s.",
display_size(cmd, (uint64_t)*pool_metadata_extents * extent_size));
return 1;
}
/*
* Validate if existing cache-pool can be used with given chunk size
* i.e. cache-pool metadata size fits all info.
*/
int validate_lv_cache_chunk_size(struct logical_volume *pool_lv, uint32_t chunk_size)
{
struct volume_group *vg = pool_lv->vg;
const uint64_t max_chunks = get_default_allocation_cache_pool_max_chunks_CFG(vg->cmd, pool_lv->profile);
uint64_t min_size = _cache_min_metadata_size(pool_lv->size, chunk_size);
uint64_t chunks = pool_lv->size / chunk_size;
int r = 1;
if (min_size > first_seg(pool_lv)->metadata_lv->size) {
log_error("Cannot use chunk size %s with cache pool %s metadata size %s.",
display_size(vg->cmd, chunk_size),
display_lvname(pool_lv),
display_size(vg->cmd, first_seg(pool_lv)->metadata_lv->size));
log_error("Minimal size for cache pool %s metadata with chunk size %s would be %s.",
display_lvname(pool_lv),
display_size(vg->cmd, chunk_size),
display_size(vg->cmd, min_size));
r = 0;
}
if (chunks > max_chunks) {
log_error("Cannot use too small chunk size %s with cache pool %s data volume size %s.",
display_size(vg->cmd, chunk_size),
display_lvname(pool_lv),
display_size(pool_lv->vg->cmd, pool_lv->size));
log_error("Maximum configured chunks for a cache pool is " FMTu64 ".",
max_chunks);
log_error("Use smaller cache pool (<%s) or bigger cache chunk size (>=%s) or enable higher "
"values in 'allocation/cache_pool_max_chunks'.",
display_size(vg->cmd, chunk_size * max_chunks),
display_size(vg->cmd, pool_lv->size / max_chunks));
r = 0;
}
return r;
}
/*
* Validate arguments for converting origin into cached volume with given cache pool.
*
* Always validates origin_lv, and when it is known also cache pool_lv
*/
int validate_lv_cache_create_pool(const struct logical_volume *pool_lv)
{
struct lv_segment *seg;
if (lv_is_locked(pool_lv)) {
log_error("Cannot use locked cache pool %s.",
display_lvname(pool_lv));
return 0;
}
if (!dm_list_empty(&pool_lv->segs_using_this_lv)) {
seg = get_only_segment_using_this_lv(pool_lv);
log_error("Logical volume %s is already in use by %s.",
display_lvname(pool_lv),
seg ? display_lvname(seg->lv) : "another LV");
return 0;
}
return 1;
}
int validate_lv_cache_create_origin(const struct logical_volume *origin_lv)
{
if (lv_is_locked(origin_lv)) {
log_error("Cannot use locked origin volume %s.",
display_lvname(origin_lv));
return 0;
}
/* For now we only support conversion of thin pool data volume */
if (!lv_is_visible(origin_lv) &&
!lv_is_thin_pool_data(origin_lv) &&
!lv_is_vdo_pool_data(origin_lv)) {
log_error("Can't convert internal LV %s.", display_lvname(origin_lv));
return 0;
}
/*
* Only linear, striped or raid supported.
* FIXME Tidy up all these type restrictions.
*/
if (lv_is_cache_type(origin_lv) ||
lv_is_mirror_type(origin_lv) ||
lv_is_thin_volume(origin_lv) || lv_is_thin_pool_metadata(origin_lv) ||
lv_is_merging_origin(origin_lv) ||
lv_is_cow(origin_lv) || lv_is_merging_cow(origin_lv) ||
/* TODO: think about enabling caching of a single thin volume */
(lv_is_virtual(origin_lv) && !lv_is_vdo(origin_lv))) {
log_error("Cache is not supported with %s segment type of the original logical volume %s.",
lvseg_name(first_seg(origin_lv)), display_lvname(origin_lv));
return 0;
}
return 1;
}
int validate_cache_chunk_size(struct cmd_context *cmd, uint32_t chunk_size)
{
const uint32_t min_size = DM_CACHE_MIN_DATA_BLOCK_SIZE;
const uint32_t max_size = DM_CACHE_MAX_DATA_BLOCK_SIZE;
int r = 1;
if ((chunk_size < min_size) || (chunk_size > max_size)) {
log_error("Cache chunk size %s is not in the range %s to %s.",
display_size(cmd, chunk_size),
display_size(cmd, min_size),
display_size(cmd, max_size));
r = 0;
}
if (chunk_size & (min_size - 1)) {
log_error("Cache chunk size %s must be a multiple of %s.",
display_size(cmd, chunk_size),
display_size(cmd, min_size));
r = 0;
}
return r;
}
/*
* lv_cache_create
* @pool
* @origin
*
* Given a cache_pool and an origin, link the two and create a
* cached LV.
*
* Returns: cache LV on success, NULL on failure
*/
struct logical_volume *lv_cache_create(struct logical_volume *pool_lv,
struct logical_volume *origin_lv)
{
char cpool_name[NAME_LEN];
const struct segment_type *segtype;
struct cmd_context *cmd = pool_lv->vg->cmd;
struct logical_volume *cache_lv = origin_lv;
struct lv_segment *seg;
if (!validate_lv_cache_create_pool(pool_lv) ||
!validate_lv_cache_create_origin(cache_lv))
return_NULL;
if (lv_is_thin_pool(cache_lv) || lv_is_vdo_pool(cache_lv))
cache_lv = seg_lv(first_seg(cache_lv), 0); /* cache _tdata */
if (!(segtype = get_segtype_from_string(cmd, SEG_TYPE_NAME_CACHE)))
return_NULL;
if (!insert_layer_for_lv(cmd, cache_lv, CACHE, "_corig"))
return_NULL;
seg = first_seg(cache_lv);
seg->segtype = segtype;
if (!attach_pool_lv(seg, pool_lv, NULL, NULL, NULL))
return_NULL;
if (lv_is_cache_pool(pool_lv)) {
/* Used cache-pool gets _cpool suffix (easy to recognize from _cvol usage) */
if (dm_snprintf(cpool_name, sizeof(cpool_name), "%s_cpool", pool_lv->name) < 0) {
log_error("Can't prepare new cachepool name for %s.", display_lvname(pool_lv));
return NULL;
}
if (!lv_rename_update(cmd, pool_lv, cpool_name, 0))
return_NULL;
}
if (!seg->lv->profile) /* Inherit profile from cache-pool */
seg->lv->profile = seg->pool_lv->profile;
return cache_lv;
}
/*
* Checks cache status and loops until there are not dirty blocks
* Set 1 to *is_clean when there are no dirty blocks on return.
*/
int lv_cache_wait_for_clean(struct logical_volume *cache_lv, int *is_clean)
{
const struct logical_volume *lock_lv = lv_lock_holder(cache_lv);
struct lv_segment *cache_seg = first_seg(cache_lv);
struct lv_status_cache *status;
int cleaner_policy = 0, writeback;
uint64_t dirty_blocks;
*is_clean = 0;
//FIXME: use polling to do this...
for (;;) {
sigint_allow();
if (cleaner_policy)
/* TODO: Use centralized place */
usleep(500000);
sigint_restore();
if (sigint_caught()) {
sigint_clear();
log_error("Flushing of %s aborted.", display_lvname(cache_lv));
if (cache_seg->cleaner_policy) {
cache_seg->cleaner_policy = 0;
/* Restore normal table */
if (!lv_update_and_reload_origin(cache_lv))
stack;
}
return 0;
}
if (!lv_cache_status(cache_lv, &status))
return_0;
if (status->cache->fail) {
dm_pool_destroy(status->mem);
log_warn("WARNING: Skippping flush for failed cache %s.",
display_lvname(cache_lv));
return 1;
}
cleaner_policy = !strcmp(status->cache->policy_name, "cleaner");
dirty_blocks = status->cache->dirty_blocks;
writeback = (status->cache->feature_flags & DM_CACHE_FEATURE_WRITEBACK);
dm_pool_destroy(status->mem);
/* Only clear when policy is Clear or mode != writeback */
if (!dirty_blocks && (cleaner_policy || !writeback))
break;
log_print_unless_silent("Flushing " FMTu64 " blocks for cache %s.",
dirty_blocks, display_lvname(cache_lv));
if (cleaner_policy)
continue;
if (!(cache_lv->status & LVM_WRITE)) {
log_warn("WARNING: Dirty blocks found on read-only cache volume %s.",
display_lvname(cache_lv));
/* TODO: can we actually clean something? */
}
/* Switch to cleaner policy to flush the cache */
cache_seg->cleaner_policy = 1;
/* Reload cache volume with "cleaner" policy */
if (!lv_update_and_reload_origin(cache_lv))
return_0;
if (!sync_local_dev_names(cache_lv->vg->cmd)) {
log_error("Failed to sync local devices when clearing cache volume %s.",
display_lvname(cache_lv));
return 0;
}
}
/*
* TODO: add check if extra suspend resume is necessary
* ATM this is workaround for missing cache sync when cache gets clean
*/
if (cleaner_policy) {
if (!lv_refresh_suspend_resume(lock_lv))
return_0;
if (!sync_local_dev_names(cache_lv->vg->cmd)) {
log_error("Failed to sync local devices after final clearing of cache %s.",
display_lvname(cache_lv));
return 0;
}
}
cache_seg->cleaner_policy = 0;
*is_clean = 1;
return 1;
}
/*
* lv_cache_remove
* @cache_lv
*
* Given a cache LV, remove the cache layer. This will unlink
* the origin and cache_pool/cachevol, remove the cache LV layer, and promote
* the origin to a usable non-cached LV of the same name as the
* given cache_lv.
*
* Returns: 1 on success, 0 on failure
*/
int lv_cache_remove(struct logical_volume *cache_lv)
{
struct lv_segment *cache_seg = first_seg(cache_lv);
struct logical_volume *corigin_lv;
struct logical_volume *cache_pool_lv;
struct id *data_id, *metadata_id;
uint64_t data_len, metadata_len;
cache_mode_t cache_mode;
int is_clear;
if (!lv_is_cache(cache_lv)) {
log_error(INTERNAL_ERROR "LV %s is not cache volume.",
display_lvname(cache_lv));
return 0;
}
if (lv_is_pending_delete(cache_lv)) {
log_debug(INTERNAL_ERROR "LV %s is already dropped cache volume.",
display_lvname(cache_lv));
goto remove; /* Already dropped */
}
/* Localy active volume is needed for writeback */
if (!lv_info(cache_lv->vg->cmd, cache_lv, 1, NULL, 0, 0)) {
/* Give up any remote locks */
if (!deactivate_lv_with_sub_lv(cache_lv))
return_0;
cache_mode = (lv_is_cache_pool(cache_seg->pool_lv)) ?
first_seg(cache_seg->pool_lv)->cache_mode : cache_seg->cache_mode;
switch (cache_mode) {
case CACHE_MODE_WRITETHROUGH:
case CACHE_MODE_PASSTHROUGH:
/* For inactive pass/writethrough just drop cache layer */
corigin_lv = seg_lv(cache_seg, 0);
if (!detach_pool_lv(cache_seg))
return_0;
if (!remove_layer_from_lv(cache_lv, corigin_lv))
return_0;
if (!lv_remove(corigin_lv))
return_0;
return 1;
default:
/* Otherwise localy activate volume to sync dirty blocks */
cache_lv->status |= LV_TEMPORARY;
if (!activate_lv(cache_lv->vg->cmd, cache_lv) ||
!lv_is_active(cache_lv)) {
log_error("Failed to activate %s to flush cache.", display_lvname(cache_lv));
return 0;
}
cache_lv->status &= ~LV_TEMPORARY;
}
}
/*
* FIXME:
* Before the link can be broken, we must ensure that the
* cache has been flushed. This may already be the case
* if the cache mode is writethrough (or the cleaner
* policy is in place from a previous half-finished attempt
* to remove the cache_pool). It could take a long time to
* flush the cache - it should probably be done in the background.
*
* Also, if we do perform the flush in the background and we
* happen to also be removing the cache/origin LV, then we
* could check if the cleaner policy is in place and simply
* remove the cache_pool then without waiting for the flush to
* complete.
*/
if (!lv_cache_wait_for_clean(cache_lv, &is_clear))
return_0;
cache_pool_lv = cache_seg->pool_lv;
if (!detach_pool_lv(cache_seg))
return_0;
/*
* Drop layer from cache LV and make _corigin to appear again as regular LV
* And use 'existing' _corigin volume to keep reference on cache-pool
* This way we still have a way to reference _corigin in dm table and we
* know it's been 'cache' LV and we can drop all needed table entries via
* activation and deactivation of it.
*
* This 'cache' LV without origin is temporary LV, which still could be
* easily operated by lvm2 commands - it could be activate/deactivated/removed.
* However in the dm-table it will use 'error' target for _corigin volume.
*/
corigin_lv = seg_lv(cache_seg, 0);
lv_set_visible(corigin_lv);
if (!remove_layer_from_lv(cache_lv, corigin_lv))
return_0;
/* Preserve currently important data from original cache segment.
* TODO: can it be done without this ? */
data_id = cache_seg->data_id;
data_len = cache_seg->data_len;
metadata_id = cache_seg->metadata_id;
metadata_len = cache_seg->metadata_len;
/* Replace 'error' with 'cache' segtype */
cache_seg = first_seg(corigin_lv);
if (!(cache_seg->segtype = get_segtype_from_string(corigin_lv->vg->cmd, SEG_TYPE_NAME_CACHE)))
return_0;
if (!add_lv_segment_areas(cache_seg, 1))
return_0;
if (!set_lv_segment_area_lv(cache_seg, 0, cache_lv, 0, 0))
return_0;
corigin_lv->le_count = cache_lv->le_count;
corigin_lv->size = cache_lv->size;
corigin_lv->status |= LV_PENDING_DELETE;
/* Restore preserved data into a new cache segment that is going to be removed. */
if ((cache_seg->data_len = data_len)) {
cache_seg->metadata_len = metadata_len;
cache_seg->data_id = data_id;
cache_seg->metadata_id = metadata_id;
cache_pool_lv->status |= LV_CACHE_VOL;
/* Unused settings set only for passing metadata validation. */
cache_seg->cache_mode = CACHE_MODE_WRITETHROUGH;
cache_seg->chunk_size = DM_CACHE_MAX_DATA_BLOCK_SIZE;
cache_seg->cache_metadata_format = CACHE_METADATA_FORMAT_2;
}
/* Reattach cache pool */
if (!attach_pool_lv(cache_seg, cache_pool_lv, NULL, NULL, NULL))
return_0;
/* Suspend/resume also deactivates deleted LV via support of LV_PENDING_DELETE */
if (!lv_update_and_reload(cache_lv))
return_0;
cache_lv = corigin_lv;
remove:
if (!detach_pool_lv(cache_seg))
return_0;
if (!lv_remove(cache_lv)) /* Will use LV_PENDING_DELETE */
return_0;
/* CachePool or CacheVol is left inactivate for further manipulation */
return 1;
}
int lv_is_cache_origin(const struct logical_volume *lv)
{
struct lv_segment *seg;
/* Make sure there's exactly one segment in segs_using_this_lv! */
if (dm_list_empty(&lv->segs_using_this_lv) ||
(dm_list_size(&lv->segs_using_this_lv) > 1))
return 0;
seg = get_only_segment_using_this_lv(lv);
return seg && lv_is_cache(seg->lv) && !lv_is_pending_delete(seg->lv) && (seg_lv(seg, 0) == lv);
}
static const char *_get_default_cache_policy(struct cmd_context *cmd)
{
const struct segment_type *segtype = get_segtype_from_string(cmd, SEG_TYPE_NAME_CACHE);
unsigned attr = ~0;
const char *def = NULL;
if (!segtype ||
!segtype->ops->target_present ||
!segtype->ops->target_present(cmd, NULL, &attr)) {
log_warn("WARNING: Cannot detect default cache policy, using \""
DEFAULT_CACHE_POLICY "\".");
return DEFAULT_CACHE_POLICY;
}
if (attr & CACHE_FEATURE_POLICY_SMQ)
def = "smq";
else if (attr & CACHE_FEATURE_POLICY_MQ)
def = "mq";
else {
log_error("Default cache policy is not available.");
return NULL;
}
log_debug_metadata("Detected default cache_policy \"%s\".", def);
return def;
}
/* Autodetect best available cache metadata format for a user */
static cache_metadata_format_t _get_default_cache_metadata_format(struct cmd_context *cmd)
{
const struct segment_type *segtype = get_segtype_from_string(cmd, SEG_TYPE_NAME_CACHE);
unsigned attr;
cache_metadata_format_t f;
if (!segtype ||
!segtype->ops->target_present ||
!segtype->ops->target_present(cmd, NULL, &attr)) {
f = CACHE_METADATA_FORMAT_1;
log_warn("WARNING: Cannot detect default cache metadata format, using format: %u.", f);
} else {
f = (attr & CACHE_FEATURE_METADATA2) ? CACHE_METADATA_FORMAT_2 : CACHE_METADATA_FORMAT_1;
log_debug_metadata("Detected default cache metadata format: %u.", f);
}
return f;
}
int cache_set_policy(struct lv_segment *lvseg, const char *name,
const struct dm_config_tree *settings)
{
struct lv_segment *seg;
struct dm_config_node *cn;
const struct dm_config_node *cns;
struct dm_config_tree *old = NULL, *new = NULL, *tmp = NULL;
int r = 0;
struct profile *profile = lvseg->lv->profile;
if (seg_is_cache_pool(lvseg)) {
if (!name && !settings)
return 1; /* Policy and settings can be selected later when caching LV */
}
if (seg_is_cache(lvseg) && lv_is_cache_vol(lvseg->pool_lv))
seg = lvseg;
else if (seg_is_cache_pool(lvseg))
seg = lvseg;
else if (seg_is_cache(lvseg))
seg = first_seg(lvseg->pool_lv);
else {
log_error(INTERNAL_ERROR "Cannot set cache metadata format for non cache volume %s.",
display_lvname(lvseg->lv));
return 0;
}
if (name) {
if (!(seg->policy_name = dm_pool_strdup(seg->lv->vg->vgmem, name))) {
log_error("Failed to duplicate policy name.");
return 0;
}
} else if (!seg->policy_name) {
if (!(seg->policy_name = find_config_tree_str(seg->lv->vg->cmd, allocation_cache_policy_CFG,
profile)) &&
!(seg->policy_name = _get_default_cache_policy(seg->lv->vg->cmd)))
return_0;
if (!seg->policy_name) {
log_error(INTERNAL_ERROR "Can't set policy settings without policy name.");
return 0;
}
}
if (settings) {
if (seg->policy_settings) {
if (!(old = dm_config_create()))
goto_out;
if (!(new = dm_config_create()))
goto_out;
new->root = settings->root;
old->root = seg->policy_settings;
new->cascade = old;
if (!(tmp = dm_config_flatten(new)))
goto_out;
}
if ((cn = dm_config_find_node((tmp) ? tmp->root : settings->root, "policy_settings")) &&
!(seg->policy_settings = dm_config_clone_node_with_mem(seg->lv->vg->vgmem, cn, 0)))
goto_out;
} else if (!seg->policy_settings) {
if ((cns = find_config_tree_node(seg->lv->vg->cmd, allocation_cache_settings_CFG_SECTION,
profile))) {
/* Try to find our section for given policy */
for (cn = cns->child; cn; cn = cn->sib) {
if (!cn->child)
continue; /* Ignore section without settings */
if (cn->v || strcmp(cn->key, seg->policy_name) != 0)
continue; /* Ignore mismatching sections */
/* Clone nodes with policy name */
if (!(seg->policy_settings = dm_config_clone_node_with_mem(seg->lv->vg->vgmem,
cn, 0)))
return_0;
/* Replace policy name key with 'policy_settings' */
seg->policy_settings->key = "policy_settings";
break; /* Only first match counts */
}
}
}
restart: /* remove any 'default" nodes */
cn = seg->policy_settings ? seg->policy_settings->child : NULL;
while (cn) {
if (cn->v->type == DM_CFG_STRING && !strcmp(cn->v->v.str, "default")) {
dm_config_remove_node(seg->policy_settings, cn);
goto restart;
}
cn = cn->sib;
}
r = 1;
out:
if (tmp)
dm_config_destroy(tmp);
if (new)
dm_config_destroy(new);
if (old)
dm_config_destroy(old);
return r;
}
/*
* Sets metadata format on cache pool segment with these rules:
* 1. When 'cache-pool' segment is passed, sets only for selected formats (1 or 2).
* 2. For 'cache' segment passed in we know cache pool segment.
* When passed format is 0 (UNSELECTED) with 'cache' segment - it's the moment
* lvm2 has to figure out 'default' metadata format (1 or 2) from
* configuration or profiles.
* 3. If still unselected or selected format is != 1, figure the best supported format
* and either use it or validate users settings is possible.
*
* Reasoning: A user may create cache-pool and may or may not specify CMFormat.
* If the CMFormat has been selected (1 or 2) store this in metadata, otherwise
* for an unused cache-pool UNSELECTED CMFormat is used. When caching LV, CMFormat
* must be decided and from this moment it's always stored. To support backward
* compatibility 'CMFormat 1' is used when it is NOT specified for a cached LV in
* lvm2 metadata (no metadata_format=#F element in cache-pool segment).
*/
int cache_set_metadata_format(struct lv_segment *seg, cache_metadata_format_t format)
{
cache_metadata_format_t best;
struct profile *profile = seg->lv->profile;
if (seg_is_cache(seg))
seg = first_seg(seg->pool_lv);
else if (seg_is_cache_pool(seg)) {
if (format == CACHE_METADATA_FORMAT_UNSELECTED)
return 1; /* Format can be selected later when caching LV */
} else {
log_error(INTERNAL_ERROR "Cannot set cache metadata format for non cache volume %s.",
display_lvname(seg->lv));
return 0;
}
/*
* If policy is unselected, but format 2 is selected, policy smq is enforced.
*/
if (!seg->policy_name) {
if (format == CACHE_METADATA_FORMAT_2)
seg->policy_name = "smq";
}
/* Check if we need to search for configured cache metadata format */
if (format == CACHE_METADATA_FORMAT_UNSELECTED) {
if (seg->cache_metadata_format != CACHE_METADATA_FORMAT_UNSELECTED)
return 1; /* Format already selected in cache pool */
/* Check configurations and profiles */
format = find_config_tree_int(seg->lv->vg->cmd, allocation_cache_metadata_format_CFG,
profile);
}
/* See what is a 'best' available cache metadata format
* when the specifed format is other then always existing CMFormat 1 */
if (format != CACHE_METADATA_FORMAT_1) {
best = _get_default_cache_metadata_format(seg->lv->vg->cmd);
/* Format was not selected, so use best present on a system */
if (format == CACHE_METADATA_FORMAT_UNSELECTED)
format = best;
else if (format != best) {
/* Format is not valid (Only Format 1 or 2 is supported ATM) */
log_error("Cache metadata format %u is not supported by kernel target.", format);
return 0;
}
}
switch (format) {
case CACHE_METADATA_FORMAT_2: seg->lv->status |= LV_METADATA_FORMAT; break;
case CACHE_METADATA_FORMAT_1: seg->lv->status &= ~LV_METADATA_FORMAT; break;
default:
log_error(INTERNAL_ERROR "Invalid cache metadata format %u for cache volume %s.",
format, display_lvname(seg->lv));
return 0;
}
seg->cache_metadata_format = format;
return 1;
}
#define ONE_MB_IN_SECTORS 2048 /* 1MB in sectors */
#define ONE_GB_IN_SECTORS 2097152 /* 1GB in sectors */
int cache_vol_set_params(struct cmd_context *cmd,
struct logical_volume *cache_lv,
struct logical_volume *pool_lv,
uint64_t poolmetadatasize,
uint32_t chunk_size,
cache_metadata_format_t format,
cache_mode_t mode,
const char *policy,
const struct dm_config_tree *settings)
{
struct dm_pool *mem = cache_lv->vg->vgmem;
struct profile *profile = cache_lv->profile;
struct lv_segment *cache_seg = first_seg(cache_lv);
struct logical_volume *corig_lv = seg_lv(cache_seg, 0);
const char *policy_name = NULL;
struct dm_config_node *policy_settings = NULL;
const struct dm_config_node *cns;
struct dm_config_node *cn;
uint64_t meta_size = 0;
uint64_t data_size = 0;
uint64_t max_chunks;
uint32_t min_meta_size;
uint32_t max_meta_size;
uint32_t extent_size;
/* all _size variables in units of sectors (512 bytes) */
/*
* cache format: only create new cache LVs with 2.
*/
if (format == CACHE_METADATA_FORMAT_UNSELECTED)
format = CACHE_METADATA_FORMAT_2;
if (format == CACHE_METADATA_FORMAT_1) {
log_error("Use cache metadata format 2.");
return 0;
}
/*
* cache mode: get_cache_params() gets mode from --cachemode or sets
* UNSEL. When unspecified, it comes from config.
*/
if (mode == CACHE_MODE_UNSELECTED)
mode = _get_cache_mode_from_config(cmd, profile, cache_lv);
cache_seg->cache_mode = mode;
/*
* chunk size: get_cache_params() get chunk_size from --chunksize or
* sets 0. When unspecified it comes from config or default.
*
* cache_pool_chunk_size in lvm.conf, DEFAULT_CACHE_POOL_CHUNK_SIZE,
* and DEFAULT_CACHE_POOL_MAX_METADATA_SIZE are in KiB, so *2 turn
* them into sectors.
*/
if (!chunk_size)
chunk_size = find_config_tree_int(cmd, allocation_cache_pool_chunk_size_CFG, cache_lv->profile) * 2;
if (!chunk_size)
chunk_size = get_default_allocation_cache_pool_chunk_size_CFG(cmd, profile);
if (!validate_cache_chunk_size(cmd, chunk_size))
return_0;
/*
* metadata size: can be specified with --poolmetadatasize,
* otherwise it's set according to the size of the cache.
* data size: the LV size minus the metadata size.
*/
if (!(extent_size = pool_lv->vg->extent_size)) {
log_error(INTERNAL_ERROR "Extend size can't be 0.");
return 0;
}
min_meta_size = extent_size;
max_meta_size = 2 * DEFAULT_CACHE_POOL_MAX_METADATA_SIZE; /* 2x for KiB to sectors */
if (pool_lv->size < (extent_size * 2)) {
log_error("The minimum cache size is two extents (%s bytes).",
display_size(cmd, extent_size * 2));
return 0;
}
if (poolmetadatasize) {
meta_size = poolmetadatasize; /* in sectors, from --poolmetadatasize, see _size_arg() */
if (meta_size > max_meta_size) {
meta_size = max_meta_size;
log_print_unless_silent("Rounding down metadata size to max size %s",
display_size(cmd, meta_size));
}
if (meta_size < min_meta_size) {
meta_size = min_meta_size;
log_print_unless_silent("Rounding up metadata size to min size %s",
display_size(cmd, meta_size));
}
if (meta_size % extent_size) {
meta_size += extent_size - meta_size % extent_size;
log_print_unless_silent("Rounding up metadata size to full physical extent %s",
display_size(cmd, meta_size));
}
}
if (!meta_size) {
meta_size = _cache_min_metadata_size(pool_lv->size, chunk_size);
/* fix bad value from _cache_min_metadata_size */
if (meta_size > (pool_lv->size / 2))
meta_size = pool_lv->size / 2;
if (meta_size < min_meta_size)
meta_size = min_meta_size;
if (meta_size % extent_size)
meta_size += extent_size - meta_size % extent_size;
}
data_size = pool_lv->size - meta_size;
max_chunks = get_default_allocation_cache_pool_max_chunks_CFG(cmd, profile);
if (data_size / chunk_size > max_chunks) {
log_error("Cache data blocks %llu and chunk size %u exceed max chunks %llu.",
(unsigned long long)data_size, chunk_size, (unsigned long long)max_chunks);
log_error("Use smaller cache, larger --chunksize or increase max chunks setting.");
return 0;
}
/*
* cache policy: get_cache_params() gets policy from --cachepolicy,
* or sets NULL.
*/
if (!policy)
policy = find_config_tree_str(cmd, allocation_cache_policy_CFG, profile);
if (!policy)
policy = _get_default_cache_policy(cmd);
if (!policy) {
log_error(INTERNAL_ERROR "Missing cache policy name.");
return 0;
}
if (!(policy_name = dm_pool_strdup(mem, policy)))
return_0;
/*
* cache settings: get_cache_params() gets policy from --cachesettings,
* or sets NULL.
* FIXME: code for this is a mess, mostly copied from cache_set_policy
* which is even worse.
*/
if (settings) {
if ((cn = dm_config_find_node(settings->root, "policy_settings"))) {
if (!(policy_settings = dm_config_clone_node_with_mem(mem, cn, 0)))
return_0;
}
} else {
if ((cns = find_config_tree_node(cmd, allocation_cache_settings_CFG_SECTION, profile))) {
/* Try to find our section for given policy */
for (cn = cns->child; cn; cn = cn->sib) {
if (!cn->child)
continue; /* Ignore section without settings */
if (cn->v || strcmp(cn->key, policy_name) != 0)
continue; /* Ignore mismatching sections */
/* Clone nodes with policy name */
if (!(policy_settings = dm_config_clone_node_with_mem(mem, cn, 0)))
return_0;
/* Replace policy name key with 'policy_settings' */
policy_settings->key = "policy_settings";
break; /* Only first match counts */
}
}
}
restart: /* remove any 'default" nodes */
cn = policy_settings ? policy_settings->child : NULL;
while (cn) {
if (cn->v->type == DM_CFG_STRING && !strcmp(cn->v->v.str, "default")) {
dm_config_remove_node(policy_settings, cn);
goto restart;
}
cn = cn->sib;
}
log_debug("Setting LV %s cache on %s meta start 0 len %llu data start %llu len %llu sectors",
display_lvname(cache_lv), display_lvname(pool_lv),
(unsigned long long)meta_size,
(unsigned long long)meta_size,
(unsigned long long)data_size);
log_debug("Setting LV %s cache format %u policy %s chunk_size %u sectors",
display_lvname(cache_lv), format, policy_name, chunk_size);
if (lv_is_raid(corig_lv) && (mode == CACHE_MODE_WRITEBACK))
log_warn("WARNING: Data redundancy could be lost with writeback caching of raid logical volume!");
if (lv_is_thin_pool_data(cache_lv)) {
log_warn("WARNING: thin pool data will not be automatically extended when cached.");
log_warn("WARNING: manual splitcache is required before extending thin pool data.");
}
cache_seg->chunk_size = chunk_size;
cache_seg->metadata_start = 0;
cache_seg->metadata_len = meta_size;
cache_seg->data_start = meta_size;
cache_seg->data_len = data_size;
cache_seg->cache_metadata_format = format;
cache_seg->policy_name = policy_name;
cache_seg->policy_settings = policy_settings;
/* Since we add -cdata and -cmeta to UUID we use CacheVol LV UUID */
cache_seg->data_id = cache_seg->metadata_id = NULL;
return 1;
}
int cache_set_params(struct lv_segment *seg,
uint32_t chunk_size,
cache_metadata_format_t format,
cache_mode_t mode,
const char *policy_name,
const struct dm_config_tree *policy_settings)
{
struct lv_segment *pool_seg;
struct cmd_context *cmd = seg->lv->vg->cmd;
if (!cache_set_cache_mode(seg, mode))
return_0;
if (!cache_set_policy(seg, policy_name, policy_settings))
return_0;
if (!cache_set_metadata_format(seg, format))
return_0;
pool_seg = seg_is_cache(seg) ? first_seg(seg->pool_lv) : seg;
if (chunk_size) {
if (seg_is_cache(seg) &&
!validate_lv_cache_chunk_size(pool_seg->lv, chunk_size))
return_0;
pool_seg->chunk_size = chunk_size;
} else if (seg_is_cache(seg)) {
/* Chunk size in profile has priority over cache-pool chunk size */
if ((chunk_size = find_config_tree_int(cmd, allocation_cache_pool_chunk_size_CFG,
seg->lv->profile) * 2)) {
if (!validate_lv_cache_chunk_size(pool_seg->lv, chunk_size))
return_0;
if (pool_seg->chunk_size != chunk_size)
log_verbose("Replacing chunk size %s in cache pool %s with "
"chunk size %s from profile.",
display_size(cmd, pool_seg->chunk_size),
display_lvname(seg->lv),
display_size(cmd, chunk_size));
pool_seg->chunk_size = chunk_size;
}
} else if (seg_is_cache_pool(seg)) {
if (!pool_seg->chunk_size &&
/* TODO: some calc_policy solution for cache ? */
!recalculate_pool_chunk_size_with_dev_hints(pool_seg->lv,
THIN_CHUNK_SIZE_CALC_METHOD_GENERIC))
return_0;
}
if (seg_is_cache(seg))
cache_check_for_warns(seg);
return 1;
}
/*
* Wipe cache pool metadata area before use.
*
* Activates metadata volume as 'cache-pool' so regular wiping
* of existing visible volume may proceed.
*/
int wipe_cache_pool(struct logical_volume *cache_pool_lv)
{
int r;
/* Only unused cache-pool could be activated and wiped */
if (lv_is_used_cache_pool(cache_pool_lv) || lv_is_cache_vol(cache_pool_lv)) {
log_error(INTERNAL_ERROR "Failed to wipe cache pool for volume %s.",
display_lvname(cache_pool_lv));
return 0;
}
cache_pool_lv->status |= LV_TEMPORARY;
if (!activate_lv(cache_pool_lv->vg->cmd, cache_pool_lv)) {
log_error("Aborting. Failed to activate cache pool %s.",
display_lvname(cache_pool_lv));
return 0;
}
cache_pool_lv->status &= ~LV_TEMPORARY;
if (!(r = wipe_lv(cache_pool_lv, (struct wipe_params) { .do_zero = 1 }))) {
log_error("Aborting. Failed to wipe cache pool %s.",
display_lvname(cache_pool_lv));
/* Delay return of error after deactivation */
}
/* Deactivate cleared cache-pool metadata */
if (!deactivate_lv(cache_pool_lv->vg->cmd, cache_pool_lv)) {
log_error("Aborting. Could not deactivate cache pool %s.",
display_lvname(cache_pool_lv));
r = 0;
}
return r;
}
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