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0912cf67aa
Users now have the ability to convert their existing logical volumes into cached logical volumes. A cache pool LV must be specified using the '--cachepool' argument. The cachepool is the small, fast LV used to cache the large, slow LV that is being converted.
279 lines
7.7 KiB
C
279 lines
7.7 KiB
C
/*
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* Copyright (C) 2014 Red Hat, Inc. All rights reserved.
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*
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* This file is part of LVM2.
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*
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* This copyrighted material is made available to anyone wishing to use,
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* modify, copy, or redistribute it subject to the terms and conditions
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* of the GNU Lesser General Public License v.2.1.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include "lib.h"
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#include "metadata.h"
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#include "locking.h"
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#include "pv_map.h"
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#include "lvm-string.h"
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#include "toolcontext.h"
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#include "lv_alloc.h"
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#include "pv_alloc.h"
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#include "display.h"
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#include "segtype.h"
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#include "archiver.h"
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#include "activate.h"
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#include "str_list.h"
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#include "defaults.h"
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#include "lvm-exec.h"
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int update_cache_pool_params(struct volume_group *vg, unsigned attr,
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int passed_args,
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uint32_t data_extents, uint32_t extent_size,
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int *chunk_size_calc_method, uint32_t *chunk_size,
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thin_discards_t *discards,
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uint64_t *pool_metadata_size, int *zero)
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{
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uint64_t min_meta_size;
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if ((*chunk_size < DM_CACHE_MIN_DATA_BLOCK_SIZE) ||
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(*chunk_size > DM_CACHE_MAX_DATA_BLOCK_SIZE)) {
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log_error("Chunk size must be in the range %s to %s.",
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display_size(vg->cmd, DM_CACHE_MIN_DATA_BLOCK_SIZE),
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display_size(vg->cmd, DM_CACHE_MAX_DATA_BLOCK_SIZE));
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return 0;
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}
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if (*chunk_size & (DM_CACHE_MIN_DATA_BLOCK_SIZE - 1)) {
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log_error("Chunk size must be a multiple of %u sectors.",
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DM_CACHE_MIN_DATA_BLOCK_SIZE);
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return 0;
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}
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/*
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* Default meta size is:
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* (4MiB + (16 Bytes for each chunk-sized block))
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* ... plus a good amount of padding (2x) to cover any
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* policy hint data that may be added in the future.
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*/
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min_meta_size = 16 * (data_extents * vg->extent_size);
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min_meta_size /= *chunk_size; /* # of Bytes we need */
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min_meta_size *= 2; /* plus some padding */
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min_meta_size /= 512; /* in sectors */
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min_meta_size += 4*1024*2; /* plus 4MiB */
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if (!*pool_metadata_size)
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*pool_metadata_size = min_meta_size;
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if (*pool_metadata_size < min_meta_size) {
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*pool_metadata_size = min_meta_size;
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log_print("Increasing metadata device size to %"
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PRIu64 " sectors", *pool_metadata_size);
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}
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if (*pool_metadata_size > (2 * DEFAULT_CACHE_POOL_MAX_METADATA_SIZE)) {
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*pool_metadata_size = 2 * DEFAULT_CACHE_POOL_MAX_METADATA_SIZE;
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log_print("Reducing metadata device size to %" PRIu64 " sectors",
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*pool_metadata_size);
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}
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return 1;
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}
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/*
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* lv_cache_create
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* @pool
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* @origin
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*
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* Given a cache_pool and an origin, link the two and create a
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* cached LV.
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*
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* Returns: cache LV on success, NULL on failure
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*/
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struct logical_volume *lv_cache_create(struct logical_volume *pool,
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struct logical_volume *origin)
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{
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const struct segment_type *segtype;
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struct cmd_context *cmd = pool->vg->cmd;
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struct logical_volume *cache_lv;
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struct lv_segment *seg;
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if (!lv_is_cache_pool(pool)) {
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log_error(INTERNAL_ERROR
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"%s is not a cache_pool LV", pool->name);
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return NULL;
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}
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if (!dm_list_empty(&pool->segs_using_this_lv)) {
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seg = get_only_segment_using_this_lv(pool);
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log_error("%s is already in use by %s",
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pool->name, seg ? seg->lv->name : "another LV");
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return NULL;
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}
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if (lv_is_cache_type(origin)) {
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/*
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* FIXME: We can layer caches, insert_layer_for_lv() would
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* have to do a better job renaming the LVs in the stack
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* first so that there isn't a name collision with <name>_corig.
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* The origin under the origin would become *_corig_corig
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* before renaming the origin above to *_corig.
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*/
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log_error(INTERNAL_ERROR
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"The origin, %s, cannot be of cache type",
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origin->name);
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return NULL;
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}
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if (!(segtype = get_segtype_from_string(cmd, "cache")))
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return_NULL;
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cache_lv = origin;
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if (!(origin = insert_layer_for_lv(cmd, cache_lv, CACHE, "_corig")))
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return_NULL;
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seg = first_seg(cache_lv);
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seg->segtype = segtype;
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if (!attach_pool_lv(seg, pool, NULL, NULL))
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return_NULL;
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return cache_lv;
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}
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/*
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* lv_cache_remove
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* @cache_lv
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*
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* Given a cache LV, remove the cache layer. This will unlink
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* the origin and cache_pool, remove the cache LV layer, and promote
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* the origin to a usable non-cached LV of the same name as the
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* given cache_lv.
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*
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* Returns: 1 on success, 0 on failure
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*/
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int lv_cache_remove(struct logical_volume *cache_lv)
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{
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struct cmd_context *cmd = cache_lv->vg->cmd;
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char *policy_name;
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uint64_t dirty_blocks;
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struct segment_type *segtype;
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struct lv_segment *cache_seg = first_seg(cache_lv);
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struct logical_volume *origin_lv;
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struct logical_volume *cache_pool_lv;
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if (!lv_is_cache(cache_lv))
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return_0;
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/*
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* FIXME:
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* Before the link can be broken, we must ensure that the
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* cache has been flushed. This may already be the case
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* if the cache mode is writethrough (or the cleaner
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* policy is in place from a previous half-finished attempt
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* to remove the cache_pool). It could take a long time to
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* flush the cache - it should probably be done in the background.
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*
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* Also, if we do perform the flush in the background and we
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* happen to also be removing the cache/origin LV, then we
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* could check if the cleaner policy is in place and simply
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* remove the cache_pool then without waiting for the flush to
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* complete.
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*/
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if (!lv_cache_policy_info(cache_lv, &policy_name, NULL, NULL))
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return_0;
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if (strcmp(policy_name, "cleaner")) {
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/* We must swap in the cleaner to flush the cache */
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log_error("Flushing cache for %s", cache_lv->name);
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/*
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* Is there are clean way to free the memory for the name
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* and argv when changing the policy?
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*/
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cache_seg->policy_name = (char *)"cleaner";
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cache_seg->policy_argc = 0;
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cache_seg->policy_argv = NULL;
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/* update the kernel to put the cleaner policy in place */
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if (!vg_write(cache_lv->vg))
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return_0;
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if (!suspend_lv(cmd, cache_lv))
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return_0;
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if (!vg_commit(cache_lv->vg))
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return_0;
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if (!resume_lv(cmd, cache_lv))
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return_0;
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}
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//FIXME: use polling to do this...
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do {
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if (!lv_cache_block_info(cache_lv, NULL,
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&dirty_blocks, NULL, NULL))
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return_0;
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log_error("%" PRIu64 " blocks must still be flushed.",
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dirty_blocks);
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if (dirty_blocks)
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sleep(5);
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} while (dirty_blocks);
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cache_pool_lv = first_seg(cache_lv)->pool_lv;
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if (!detach_pool_lv(first_seg(cache_lv)))
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return_0;
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origin_lv = seg_lv(first_seg(cache_lv), 0);
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lv_set_visible(origin_lv);
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//FIXME: We should be able to use 'remove_layer_from_lv', but
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// there is a call to 'lv_empty' in there that recursively
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// deletes everything down the tree - including the origin_lv
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// that we are trying to preserve!
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// if (!remove_layer_from_lv(cache_lv, origin_lv))
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// return_0;
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if (!remove_seg_from_segs_using_this_lv(origin_lv, first_seg(cache_lv)))
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return_0;
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if (!move_lv_segments(cache_lv, origin_lv, 0, 0))
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return_0;
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cache_lv->status &= ~CACHE;
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segtype = get_segtype_from_string(cmd, "error");
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if (!lv_add_virtual_segment(origin_lv, 0,
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cache_lv->le_count, segtype, NULL))
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return_0;
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if (!vg_write(cache_lv->vg))
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return_0;
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/*
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* suspend_lv on this cache LV will suspend all of the components:
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* - the top-level cache LV
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* - the origin
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* - the cache_pool and all of its sub-LVs
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*/
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if (!suspend_lv(cmd, cache_lv))
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return_0;
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if (!vg_commit(cache_lv->vg))
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return_0;
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/*
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* resume_lv on this (former) cache LV will resume all
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* but the cache_pool LV. It must be resumed seperately.
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*/
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if (!resume_lv(cmd, cache_lv))
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return_0;
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if (!resume_lv(cmd, cache_pool_lv))
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return_0;
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if (!activate_lv(cmd, origin_lv))
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return_0;
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if (!deactivate_lv(cmd, origin_lv))
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return_0;
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if (!lv_remove(origin_lv))
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return_0;
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return 1;
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}
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