// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2023 Red Hat
*/
#include "block-map.h"
#include <linux/bio.h>
#include <linux/ratelimit.h>
#include "errors.h"
#include "logger.h"
#include "memory-alloc.h"
#include "permassert.h"
#include "action-manager.h"
#include "admin-state.h"
#include "completion.h"
#include "constants.h"
#include "data-vio.h"
#include "encodings.h"
#include "io-submitter.h"
#include "physical-zone.h"
#include "recovery-journal.h"
#include "slab-depot.h"
#include "status-codes.h"
#include "types.h"
#include "vdo.h"
#include "vio.h"
#include "wait-queue.h"
/**
* DOC: Block map eras
*
* The block map era, or maximum age, is used as follows:
*
* Each block map page, when dirty, records the earliest recovery journal block sequence number of
* the changes reflected in that dirty block. Sequence numbers are classified into eras: every
* @maximum_age sequence numbers, we switch to a new era. Block map pages are assigned to eras
* according to the sequence number they record.
*
* In the current (newest) era, block map pages are not written unless there is cache pressure. In
* the next oldest era, each time a new journal block is written 1/@maximum_age of the pages in
* this era are issued for write. In all older eras, pages are issued for write immediately.
*/
struct page_descriptor {
root_count_t root_index;
height_t height;
page_number_t page_index;
slot_number_t slot;
} __packed;
union page_key {
struct page_descriptor descriptor;
u64 key;
};
struct write_if_not_dirtied_context {
struct block_map_zone *zone;
u8 generation;
};
struct block_map_tree_segment {
struct tree_page *levels[VDO_BLOCK_MAP_TREE_HEIGHT];
};
struct block_map_tree {
struct block_map_tree_segment *segments;
};
struct forest {
struct block_map *map;
size_t segments;
struct boundary *boundaries;
struct tree_page **pages;
struct block_map_tree trees[];
};
struct cursor_level {
page_number_t page_index;
slot_number_t slot;
};
struct cursors;
struct cursor {
struct vdo_waiter waiter;
struct block_map_tree *tree;
height_t height;
struct cursors *parent;
struct boundary boundary;
struct cursor_level levels[VDO_BLOCK_MAP_TREE_HEIGHT];
struct pooled_vio *vio;
};
struct cursors {
struct block_map_zone *zone;
struct vio_pool *pool;
vdo_entry_callback_fn entry_callback;
struct vdo_completion *completion;
root_count_t active_roots;
struct cursor cursors[];
};
static const physical_block_number_t NO_PAGE = 0xFFFFFFFFFFFFFFFF;
/* Used to indicate that the page holding the location of a tree root has been "loaded". */
static const physical_block_number_t VDO_INVALID_PBN = 0xFFFFFFFFFFFFFFFF;
const struct block_map_entry UNMAPPED_BLOCK_MAP_ENTRY = {
.mapping_state = VDO_MAPPING_STATE_UNMAPPED & 0x0F,
.pbn_high_nibble = 0,
.pbn_low_word = __cpu_to_le32(VDO_ZERO_BLOCK & UINT_MAX),
};
#define LOG_INTERVAL 4000
#define DISPLAY_INTERVAL 100000
/*
* For adjusting VDO page cache statistic fields which are only mutated on the logical zone thread.
* Prevents any compiler shenanigans from affecting other threads reading those stats.
*/
#define ADD_ONCE(value, delta) WRITE_ONCE(value, (value) + (delta))
static inline bool is_dirty(const struct page_info *info)
{
return info->state == PS_DIRTY;
}
static inline bool is_present(const struct page_info *info)
{
return (info->state == PS_RESIDENT) || (info->state == PS_DIRTY);
}
static inline bool is_in_flight(const struct page_info *info)
{
return (info->state == PS_INCOMING) || (info->state == PS_OUTGOING);
}
static inline bool is_incoming(const struct page_info *info)
{
return info->state == PS_INCOMING;
}
static inline bool is_outgoing(const struct page_info *info)
{
return info->state == PS_OUTGOING;
}
static inline bool is_valid(const struct page_info *info)
{
return is_present(info) || is_outgoing(info);
}
static char *get_page_buffer(struct page_info *info)
{
struct vdo_page_cache *cache = info->cache;
return &cache->pages[(info - cache->infos) * VDO_BLOCK_SIZE];
}
static inline struct vdo_page_completion *page_completion_from_waiter(struct vdo_waiter *waiter)
{
struct vdo_page_completion *completion;
if (waiter == NULL)
return NULL;
completion = container_of(waiter, struct vdo_page_completion, waiter);
vdo_assert_completion_type(&completion->completion, VDO_PAGE_COMPLETION);
return completion;
}
/**
* initialize_info() - Initialize all page info structures and put them on the free list.
*
* Return: VDO_SUCCESS or an error.
*/
static int initialize_info(struct vdo_page_cache *cache)
{
struct page_info *info;
INIT_LIST_HEAD(&cache->free_list);
for (info = cache->infos; info < cache->infos + cache->page_count; info++) {
int result;
info->cache = cache;
info->state = PS_FREE;
info->pbn = NO_PAGE;
result = create_metadata_vio(cache->vdo, VIO_TYPE_BLOCK_MAP,
VIO_PRIORITY_METADATA, info,
get_page_buffer(info), &info->vio);
if (result != VDO_SUCCESS)
return result;
/* The thread ID should never change. */
info->vio->completion.callback_thread_id = cache->zone->thread_id;
INIT_LIST_HEAD(&info->state_entry);
list_add_tail(&info->state_entry, &cache->free_list);
INIT_LIST_HEAD(&info->lru_entry);
}
return VDO_SUCCESS;
}
/**
* allocate_cache_components() - Allocate components of the cache which require their own
* allocation.
* @maximum_age: The number of journal blocks before a dirtied page is considered old and must be
* written out.
*
* The caller is responsible for all clean up on errors.
*
* Return: VDO_SUCCESS or an error code.
*/
static int __must_check allocate_cache_components(struct vdo_page_cache *cache)
{
u64 size = cache->page_count * (u64) VDO_BLOCK_SIZE;
int result;
result = vdo_allocate(cache->page_count, struct page_info, "page infos",
&cache->infos);
if (result != VDO_SUCCESS)
return result;
result = vdo_allocate_memory(size, VDO_BLOCK_SIZE, "cache pages", &cache->pages);
if (result != VDO_SUCCESS)
return result;
result = vdo_int_map_create(cache->page_count, &cache->page_map);
if (result != VDO_SUCCESS)
return result;
return initialize_info(cache);
}
/**
* assert_on_cache_thread() - Assert that a function has been called on the VDO page cache's
* thread.
*/
static inline void assert_on_cache_thread(struct vdo_page_cache *cache,
const char *function_name)
{
thread_id_t thread_id = vdo_get_callback_thread_id();
VDO_ASSERT_LOG_ONLY((thread_id == cache->zone->thread_id),
"%s() must only be called on cache thread %d, not thread %d",
function_name, cache->zone->thread_id, thread_id);
}
/** assert_io_allowed() - Assert that a page cache may issue I/O. */
static inline void assert_io_allowed(struct vdo_page_cache *cache)
{
VDO_ASSERT_LOG_ONLY(!vdo_is_state_quiescent(&cache->zone->state),
"VDO page cache may issue I/O");
}
/** report_cache_pressure() - Log and, if enabled, report cache pressure. */
static void report_cache_pressure(struct vdo_page_cache *cache)
{
ADD_ONCE(cache->stats.cache_pressure, 1);
if (cache->waiter_count > cache->page_count) {
if ((cache->pressure_report % LOG_INTERVAL) == 0)
vdo_log_info("page cache pressure %u", cache->stats.cache_pressure);
if (++cache->pressure_report >= DISPLAY_INTERVAL)
cache->pressure_report = 0;
}
}
/**
* get_page_state_name() - Return the name of a page state.
*
* If the page state is invalid a static string is returned and the invalid state is logged.
*
* Return: A pointer to a static page state name.
*/
static const char * __must_check get_page_state_name(enum vdo_page_buffer_state state)
{
int result;
static const char * const state_names[] = {
"FREE", "INCOMING", "FAILED", "RESIDENT", "DIRTY", "OUTGOING"
};
BUILD_BUG_ON(ARRAY_SIZE(state_names) != PAGE_STATE_COUNT);
result = VDO_ASSERT(state < ARRAY_SIZE(state_names),
"Unknown page_state value %d", state);
if (result != VDO_SUCCESS)
return "[UNKNOWN PAGE STATE]";
return state_names[state];
}
/**
* update_counter() - Update the counter associated with a given state.
* @info: The page info to count.
* @delta: The delta to apply to the counter.
*/
static void update_counter(struct page_info *info, s32 delta)
{
struct block_map_statistics *stats = &info->cache->stats;
switch (info->state) {
case PS_FREE:
ADD_ONCE(stats->free_pages, delta);
return;
case PS_INCOMING:
ADD_ONCE(stats->incoming_pages, delta);
return;
case PS_OUTGOING:
ADD_ONCE(stats->outgoing_pages, delta);
return;
case PS_FAILED:
ADD_ONCE(stats->failed_pages, delta);
return;
case PS_RESIDENT:
ADD_ONCE(stats->clean_pages, delta);
return;
case PS_DIRTY:
ADD_ONCE(stats->dirty_pages, delta);
return;
default:
return;
}
}
/** update_lru() - Update the lru information for an active page. */
static void update_lru(struct page_info *info)
{
if (info->cache->lru_list.prev != &info->lru_entry)
list_move_tail(&info->lru_entry, &info->cache->lru_list);
}
/**
* set_info_state() - Set the state of a page_info and put it on the right list, adjusting
* counters.
*/
static void set_info_state(struct page_info *info, enum vdo_page_buffer_state new_state)
{
if (new_state == info->state)
return;
update_counter(info, -1);
info->state = new_state;
update_counter(info, 1);
switch (info->state) {
case PS_FREE:
case PS_FAILED:
list_move_tail(&info->state_entry, &info->cache->free_list);
return;
case PS_OUTGOING:
list_move_tail(&info->state_entry, &info->cache->outgoing_list);
return;
case PS_DIRTY:
return;
default:
list_del_init(&info->state_entry);
}
}
/** set_info_pbn() - Set the pbn for an info, updating the map as needed. */
static int __must_check set_info_pbn(struct page_info *info, physical_block_number_t pbn)
{
struct vdo_page_cache *cache = info->cache;
/* Either the new or the old page number must be NO_PAGE. */
int result = VDO_ASSERT((pbn == NO_PAGE) || (info->pbn == NO_PAGE),
"Must free a page before reusing it.");
if (result != VDO_SUCCESS)
return result;
if (info->pbn != NO_PAGE)
vdo_int_map_remove(cache->page_map, info->pbn);
info->pbn = pbn;
if (pbn != NO_PAGE) {
result = vdo_int_map_put(cache->page_map, pbn, info, true, NULL);
if (result != VDO_SUCCESS)
return result;
}
return VDO_SUCCESS;
}
/** reset_page_info() - Reset page info to represent an unallocated page. */
static int reset_page_info(struct page_info *info)
{
int result;
result = VDO_ASSERT(info->busy == 0, "VDO Page must not be busy");
if (result != VDO_SUCCESS)
return result;
result = VDO_ASSERT(!vdo_waitq_has_waiters(&info->waiting),
"VDO Page must not have waiters");
if (result != VDO_SUCCESS)
return result;
result = set_info_pbn(info, NO_PAGE);
set_info_state(info, PS_FREE);
list_del_init(&info->lru_entry);
return result;
}
/**
* find_free_page() - Find a free page.
*
* Return: A pointer to the page info structure (if found), NULL otherwise.
*/
static struct page_info * __must_check find_free_page(struct vdo_page_cache *cache)
{
struct page_info *info;
info = list_first_entry_or_null(&cache->free_list, struct page_info,
state_entry);
if (info != NULL)
list_del_init(&info->state_entry);
return info;
}
/**
* find_page() - Find the page info (if any) associated with a given pbn.
* @pbn: The absolute physical block number of the page.
*
* Return: The page info for the page if available, or NULL if not.
*/
static struct page_info * __must_check find_page(struct vdo_page_cache *cache,
physical_block_number_t pbn)
{
if ((cache->last_found != NULL) && (cache->last_found->pbn == pbn))
return cache->last_found;
cache->last_found = vdo_int_map_get(cache->page_map, pbn);
return cache->last_found;
}
/**
* select_lru_page() - Determine which page is least recently used.
*
* Picks the least recently used from among the non-busy entries at the front of each of the lru
* ring. Since whenever we mark a page busy we also put it to the end of the ring it is unlikely
* that the entries at the front are busy unless the queue is very short, but not impossible.
*
* Return: A pointer to the info structure for a relevant page, or NULL if no such page can be
* found. The page can be dirty or resident.
*/
static struct page_info * __must_check select_lru_page(struct vdo_page_cache *cache)
{
struct page_info *info;
list_for_each_entry(info, &cache->lru_list, lru_entry)
if ((info->busy == 0) && !is_in_flight(info))
return info;
return NULL;
}
/* ASYNCHRONOUS INTERFACE BEYOND THIS POINT */
/**
* complete_with_page() - Helper to complete the VDO Page Completion request successfully.
* @info: The page info representing the result page.
* @vdo_page_comp: The VDO page completion to complete.
*/
static void complete_with_page(struct page_info *info,
struct vdo_page_completion *vdo_page_comp)
{
bool available = vdo_page_comp->writable ? is_present(info) : is_valid(info);
if (!available) {
vdo_log_error_strerror(VDO_BAD_PAGE,
"Requested cache page %llu in state %s is not %s",
(unsigned long long) info->pbn,
get_page_state_name(info->state),
vdo_page_comp->writable ? "present" : "valid");
vdo_fail_completion(&vdo_page_comp->completion, VDO_BAD_PAGE);
return;
}
vdo_page_comp->info = info;
vdo_page_comp->ready = true;
vdo_finish_completion(&vdo_page_comp->completion);
}
/**
* complete_waiter_with_error() - Complete a page completion with an error code.
* @waiter: The page completion, as a waiter.
* @result_ptr: A pointer to the error code.
*
* Implements waiter_callback_fn.
*/
static void complete_waiter_with_error(struct vdo_waiter *waiter, void *result_ptr)
{
int *result = result_ptr;
vdo_fail_completion(&page_completion_from_waiter(waiter)->completion, *result);
}
/**
* complete_waiter_with_page() - Complete a page completion with a page.
* @waiter: The page completion, as a waiter.
* @page_info: The page info to complete with.
*
* Implements waiter_callback_fn.
*/
static void complete_waiter_with_page(struct vdo_waiter *waiter, void *page_info)
{
complete_with_page(page_info, page_completion_from_waiter(waiter));
}
/**
* distribute_page_over_waitq() - Complete a waitq of VDO page completions with a page result.
*
* Upon completion the waitq will be empty.
*
* Return: The number of pages distributed.
*/
static unsigned int distribute_page_over_waitq(struct page_info *info,
struct vdo_wait_queue *waitq)
{
size_t num_pages;
update_lru(info);
num_pages = vdo_waitq_num_waiters(waitq);
/*
* Increment the busy count once for each pending completion so that this page does not
* stop being busy until all completions have been processed.
*/
info->busy += num_pages;
vdo_waitq_notify_all_waiters(waitq, complete_waiter_with_page, info);
return num_pages;
}
/**
* set_persistent_error() - Set a persistent error which all requests will receive in the future.
* @context: A string describing what triggered the error.
*
* Once triggered, all enqueued completions will get this error. Any future requests will result in
* this error as well.
*/
static void set_persistent_error(struct vdo_page_cache *cache, const char *context,
int result)
{
struct page_info *info;
/* If we're already read-only, there's no need to log. */
struct vdo *vdo = cache->vdo;
if ((result != VDO_READ_ONLY) && !vdo_is_read_only(vdo)) {
vdo_log_error_strerror(result, "VDO Page Cache persistent error: %s",
context);
vdo_enter_read_only_mode(vdo, result);
}
assert_on_cache_thread(cache, __func__);
vdo_waitq_notify_all_waiters(&cache->free_waiters,
complete_waiter_with_error, &result);
cache->waiter_count = 0;
for (info = cache->infos; info < cache->infos + cache->page_count; info++) {
vdo_waitq_notify_all_waiters(&info->waiting,
complete_waiter_with_error, &result);
}
}
/**
* validate_completed_page() - Check that a page completion which is being freed to the cache
* referred to a valid page and is in a valid state.
* @writable: Whether a writable page is required.
*
* Return: VDO_SUCCESS if the page was valid, otherwise as error
*/
static int __must_check validate_completed_page(struct vdo_page_completion *completion,
bool writable)
{
int result;
result = VDO_ASSERT(completion->ready, "VDO Page completion not ready");
if (result != VDO_SUCCESS)
return result;
result = VDO_ASSERT(completion->info != NULL,
"VDO Page Completion must be complete");
if (result != VDO_SUCCESS)
return result;
result = VDO_ASSERT(completion->info->pbn == completion->pbn,
"VDO Page Completion pbn must be consistent");
if (result != VDO_SUCCESS)
return result;
result = VDO_ASSERT(is_valid(completion->info),
"VDO Page Completion page must be valid");
if (result != VDO_SUCCESS)
return result;
if (writable) {
result = VDO_ASSERT(completion->writable,
"VDO Page Completion must be writable");
if (result != VDO_SUCCESS)
return result;
}
return VDO_SUCCESS;
}
static void check_for_drain_complete(struct block_map_zone *zone)
{
if (vdo_is_state_draining(&zone->state) &&
(zone->active_lookups == 0) &&
!vdo_waitq_has_waiters(&zone->flush_waiters) &&
!is_vio_pool_busy(zone->vio_pool) &&
(zone->page_cache.outstanding_reads == 0) &&
(zone->page_cache.outstanding_writes == 0)) {
vdo_finish_draining_with_result(&zone->state,
(vdo_is_read_only(zone->block_map->vdo) ?
VDO_READ_ONLY : VDO_SUCCESS));
}
}
static void enter_zone_read_only_mode(struct block_map_zone *zone, int result)
{
vdo_enter_read_only_mode(zone->block_map->vdo, result);
/*
* We are in read-only mode, so we won't ever write any page out.
* Just take all waiters off the waitq so the zone can drain.
*/
vdo_waitq_init(&zone->flush_waiters);
check_for_drain_complete(zone);
}
static bool __must_check
validate_completed_page_or_enter_read_only_mode(struct vdo_page_completion *completion,
bool writable)
{
int result = validate_completed_page(completion, writable);
if (result == VDO_SUCCESS)
return true;
enter_zone_read_only_mode(completion->info->cache->zone, result);
return false;
}
/**
* handle_load_error() - Handle page load errors.
* @completion: The page read vio.
*/
static void handle_load_error(struct vdo_completion *completion)
{
int result = completion->result;
struct page_info *info = completion->parent;
struct vdo_page_cache *cache = info->cache;
assert_on_cache_thread(cache, __func__);
vio_record_metadata_io_error(as_vio(completion));
vdo_enter_read_only_mode(cache->zone->block_map->vdo, result);
ADD_ONCE(cache->stats.failed_reads, 1);
set_info_state(info, PS_FAILED);
vdo_waitq_notify_all_waiters(&info->waiting, complete_waiter_with_error, &result);
reset_page_info(info);
/*
* Don't decrement until right before calling check_for_drain_complete() to
* ensure that the above work can't cause the page cache to be freed out from under us.
*/
cache->outstanding_reads--;
check_for_drain_complete(cache->zone);
}
/**
* page_is_loaded() - Callback used when a page has been loaded.
* @completion: The vio which has loaded the page. Its parent is the page_info.
*/
static void page_is_loaded(struct vdo_completion *completion)
{
struct page_info *info = completion->parent;
struct vdo_page_cache *cache = info->cache;
nonce_t nonce = info->cache->zone->block_map->nonce;
struct block_map_page *page;
enum block_map_page_validity validity;
assert_on_cache_thread(cache, __func__);
page = (struct block_map_page *) get_page_buffer(info);
validity = vdo_validate_block_map_page(page, nonce, info->pbn);
if (validity == VDO_BLOCK_MAP_PAGE_BAD) {
physical_block_number_t pbn = vdo_get_block_map_page_pbn(page);
int result = vdo_log_error_strerror(VDO_BAD_PAGE,
"Expected page %llu but got page %llu instead",
(unsigned long long) info->pbn,
(unsigned long long) pbn);
vdo_continue_completion(completion, result);
return;
}
if (validity == VDO_BLOCK_MAP_PAGE_INVALID)
vdo_format_block_map_page(page, nonce, info->pbn, false);
info->recovery_lock = 0;
set_info_state(info, PS_RESIDENT);
distribute_page_over_waitq(info, &info->waiting);
/*
* Don't decrement until right before calling check_for_drain_complete() to
* ensure that the above work can't cause the page cache to be freed out from under us.
*/
cache->outstanding_reads--;
check_for_drain_complete(cache->zone);
}
/**
* handle_rebuild_read_error() - Handle a read error during a read-only rebuild.
* @completion: The page load completion.
*/
static void handle_rebuild_read_error(struct vdo_completion *completion)
{
struct page_info *info = completion->parent;
struct vdo_page_cache *cache = info->cache;
assert_on_cache_thread(cache, __func__);
/*
* We are doing a read-only rebuild, so treat this as a successful read
* of an uninitialized page.
*/
vio_record_metadata_io_error(as_vio(completion));
ADD_ONCE(cache->stats.failed_reads, 1);
memset(get_page_buffer(info), 0, VDO_BLOCK_SIZE);
vdo_reset_completion(completion);
page_is_loaded(completion);
}
static void load_cache_page_endio(struct bio *bio)
{
struct vio *vio = bio->bi_private;
struct page_info *info = vio->completion.parent;
continue_vio_after_io(vio, page_is_loaded, info->cache->zone->thread_id);
}
/**
* launch_page_load() - Begin the process of loading a page.
*
* Return: VDO_SUCCESS or an error code.
*/
static int __must_check launch_page_load(struct page_info *info,
physical_block_number_t pbn)
{
int result;
vdo_action_fn callback;
struct vdo_page_cache *cache = info->cache;
assert_io_allowed(cache);
result = set_info_pbn(info, pbn);
if (result != VDO_SUCCESS)
return result;
result = VDO_ASSERT((info->busy == 0), "Page is not busy before loading.");
if (result != VDO_SUCCESS)
return result;
set_info_state(info, PS_INCOMING);
cache->outstanding_reads++;
ADD_ONCE(cache->stats.pages_loaded, 1);
callback = (cache->rebuilding ? handle_rebuild_read_error : handle_load_error);
vdo_submit_metadata_vio(info->vio, pbn, load_cache_page_endio,
callback, REQ_OP_READ | REQ_PRIO);
return VDO_SUCCESS;
}
static void write_pages(struct vdo_completion *completion);
/** handle_flush_error() - Handle errors flushing the layer. */
static void handle_flush_error(struct vdo_completion *completion)
{
struct page_info *info = completion->parent;
vio_record_metadata_io_error(as_vio(completion));
set_persistent_error(info->cache, "flush failed", completion->result);
write_pages(completion);
}
static void flush_endio(struct bio *bio)
{
struct vio *vio = bio->bi_private;
struct page_info *info = vio->completion.parent;
continue_vio_after_io(vio, write_pages, info->cache->zone->thread_id);
}
/** save_pages() - Attempt to save the outgoing pages by first flushing the layer. */
static void save_pages(struct vdo_page_cache *cache)
{
struct page_info *info;
struct vio *vio;
if ((cache->pages_in_flush > 0) || (cache->pages_to_flush == 0))
return;
assert_io_allowed(cache);
info = list_first_entry(&cache->outgoing_list, struct page_info, state_entry);
cache->pages_in_flush = cache->pages_to_flush;
cache->pages_to_flush = 0;
ADD_ONCE(cache->stats.flush_count, 1);
vio = info->vio;
/*
* We must make sure that the recovery journal entries that changed these pages were
* successfully persisted, and thus must issue a flush before each batch of pages is
* written to ensure this.
*/
vdo_submit_flush_vio(vio, flush_endio, handle_flush_error);
}
/**
* schedule_page_save() - Add a page to the outgoing list of pages waiting to be saved.
*
* Once in the list, a page may not be used until it has been written out.
*/
static void schedule_page_save(struct page_info *info)
{
if (info->busy > 0) {
info->write_status = WRITE_STATUS_DEFERRED;
return;
}
info->cache->pages_to_flush++;
info->cache->outstanding_writes++;
set_info_state(info, PS_OUTGOING);
}
/**
* launch_page_save() - Add a page to outgoing pages waiting to be saved, and then start saving
* pages if another save is not in progress.
*/
static void launch_page_save(struct page_info *info)
{
schedule_page_save(info);
save_pages(info->cache);
}
/**
* completion_needs_page() - Determine whether a given vdo_page_completion (as a waiter) is
* requesting a given page number.
* @context: A pointer to the pbn of the desired page.
*
* Implements waiter_match_fn.
*
* Return: true if the page completion is for the desired page number.
*/
static bool completion_needs_page(struct vdo_waiter *waiter, void *context)
{
physical_block_number_t *pbn = context;
return (page_completion_from_waiter(waiter)->pbn == *pbn);
}
/**
* allocate_free_page() - Allocate a free page to the first completion in the waiting queue, and
* any other completions that match it in page number.
*/
static void allocate_free_page(struct page_info *info)
{
int result;
struct vdo_waiter *oldest_waiter;
physical_block_number_t pbn;
struct vdo_page_cache *cache = info->cache;
assert_on_cache_thread(cache, __func__);
if (!vdo_waitq_has_waiters(&cache->free_waiters)) {
if (cache->stats.cache_pressure > 0) {
vdo_log_info("page cache pressure relieved");
WRITE_ONCE(cache->stats.cache_pressure, 0);
}
return;
}
result = reset_page_info(info);
if (result != VDO_SUCCESS) {
set_persistent_error(cache, "cannot reset page info", result);
return;
}
oldest_waiter = vdo_waitq_get_first_waiter(&cache->free_waiters);
pbn = page_completion_from_waiter(oldest_waiter)->pbn;
/*
* Remove all entries which match the page number in question and push them onto the page
* info's waitq.
*/
vdo_waitq_dequeue_matching_waiters(&cache->free_waiters, completion_needs_page,
&pbn, &info->waiting);
cache->waiter_count -= vdo_waitq_num_waiters(&info->waiting);
result = launch_page_load(info, pbn);
if (result != VDO_SUCCESS) {
vdo_waitq_notify_all_waiters(&info->waiting,
complete_waiter_with_error, &result);
}
}
/**
* discard_a_page() - Begin the process of discarding a page.
*
* If no page is discardable, increments a count of deferred frees so that the next release of a
* page which is no longer busy will kick off another discard cycle. This is an indication that the
* cache is not big enough.
*
* If the selected page is not dirty, immediately allocates the page to the oldest completion
* waiting for a free page.
*/
static void discard_a_page(struct vdo_page_cache *cache)
{
struct page_info *info = select_lru_page(cache);
if (info == NULL) {
report_cache_pressure(cache);
return;
}
if (!is_dirty(info)) {
allocate_free_page(info);
return;
}
VDO_ASSERT_LOG_ONLY(!is_in_flight(info),
"page selected for discard is not in flight");
cache->discard_count++;
info->write_status = WRITE_STATUS_DISCARD;
launch_page_save(info);
}
/**
* discard_page_for_completion() - Helper used to trigger a discard so that the completion can get
* a different page.
*/
static void discard_page_for_completion(struct vdo_page_completion *vdo_page_comp)
{
struct vdo_page_cache *cache = vdo_page_comp->cache;
cache->waiter_count++;
vdo_waitq_enqueue_waiter(&cache->free_waiters, &vdo_page_comp->waiter);
discard_a_page(cache);
}
/**
* discard_page_if_needed() - Helper used to trigger a discard if the cache needs another free
* page.
* @cache: The page cache.
*/
static void discard_page_if_needed(struct vdo_page_cache *cache)
{
if (cache->waiter_count > cache->discard_count)
discard_a_page(cache);
}
/**
* write_has_finished() - Inform the cache that a write has finished (possibly with an error).
* @info: The info structure for the page whose write just completed.
*
* Return: true if the page write was a discard.
*/
static bool write_has_finished(struct page_info *info)
{
bool was_discard = (info->write_status == WRITE_STATUS_DISCARD);
assert_on_cache_thread(info->cache, __func__);
info->cache->outstanding_writes--;
info->write_status = WRITE_STATUS_NORMAL;
return was_discard;
}
/**
* handle_page_write_error() - Handler for page write errors.
* @completion: The page write vio.
*/
static void handle_page_write_error(struct vdo_completion *completion)
{
int result = completion->result;
struct page_info *info = completion->parent;
struct vdo_page_cache *cache = info->cache;
vio_record_metadata_io_error(as_vio(completion));
/* If we're already read-only, write failures are to be expected. */
if (result != VDO_READ_ONLY) {
vdo_log_ratelimit(vdo_log_error,
"failed to write block map page %llu",
(unsigned long long) info->pbn);
}
set_info_state(info, PS_DIRTY);
ADD_ONCE(cache->stats.failed_writes, 1);
set_persistent_error(cache, "cannot write page", result);
if (!write_has_finished(info))
discard_page_if_needed(cache);
check_for_drain_complete(cache->zone);
}
static void page_is_written_out(struct vdo_completion *completion);
static void write_cache_page_endio(struct bio *bio)
{
struct vio *vio = bio->bi_private;
struct page_info *info = vio->completion.parent;
continue_vio_after_io(vio, page_is_written_out, info->cache->zone->thread_id);
}
/**
* page_is_written_out() - Callback used when a page has been written out.
* @completion: The vio which wrote the page. Its parent is a page_info.
*/
static void page_is_written_out(struct vdo_completion *completion)
{
bool was_discard, reclaimed;
u32 reclamations;
struct page_info *info = completion->parent;
struct vdo_page_cache *cache = info->cache;
struct block_map_page *page = (struct block_map_page *) get_page_buffer(info);
if (!page->header.initialized) {
page->header.initialized = true;
vdo_submit_metadata_vio(info->vio, info->pbn,
write_cache_page_endio,
handle_page_write_error,
REQ_OP_WRITE | REQ_PRIO | REQ_PREFLUSH);
return;
}
/* Handle journal updates and torn write protection. */
vdo_release_recovery_journal_block_reference(cache->zone->block_map->journal,
info->recovery_lock,
VDO_ZONE_TYPE_LOGICAL,
cache->zone->zone_number);
info->recovery_lock = 0;
was_discard = write_has_finished(info);
reclaimed = (!was_discard || (info->busy > 0) || vdo_waitq_has_waiters(&info->waiting));
set_info_state(info, PS_RESIDENT);
reclamations = distribute_page_over_waitq(info, &info->waiting);
ADD_ONCE(cache->stats.reclaimed, reclamations);
if (was_discard)
cache->discard_count--;
if (reclaimed)
discard_page_if_needed(cache);
else
allocate_free_page(info);
check_for_drain_complete(cache->zone);
}
/**
* write_pages() - Write the batch of pages which were covered by the layer flush which just
* completed.
* @flush_completion: The flush vio.
*
* This callback is registered in save_pages().
*/
static void write_pages(struct vdo_completion *flush_completion)
{
struct vdo_page_cache *cache = ((struct page_info *) flush_completion->parent)->cache;
/*
* We need to cache these two values on the stack since it is possible for the last
* page info to cause the page cache to get freed. Hence once we launch the last page,
* it may be unsafe to dereference the cache.
*/
bool has_unflushed_pages = (cache->pages_to_flush > 0);
page_count_t pages_in_flush = cache->pages_in_flush;
cache->pages_in_flush = 0;
while (pages_in_flush-- > 0) {
struct page_info *info =
list_first_entry(&cache->outgoing_list, struct page_info,
state_entry);
list_del_init(&info->state_entry);
if (vdo_is_read_only(info->cache->vdo)) {
struct vdo_completion *completion = &info->vio->completion;
vdo_reset_completion(completion);
completion->callback = page_is_written_out;
completion->error_handler = handle_page_write_error;
vdo_fail_completion(completion, VDO_READ_ONLY);
continue;
}
ADD_ONCE(info->cache->stats.pages_saved, 1);
vdo_submit_metadata_vio(info->vio, info->pbn, write_cache_page_endio,
handle_page_write_error, REQ_OP_WRITE | REQ_PRIO);
}
if (has_unflushed_pages) {
/*
* If there are unflushed pages, the cache can't have been freed, so this call is
* safe.
*/
save_pages(cache);
}
}
/**
* vdo_release_page_completion() - Release a VDO Page Completion.
*
* The page referenced by this completion (if any) will no longer be held busy by this completion.
* If a page becomes discardable and there are completions awaiting free pages then a new round of
* page discarding is started.
*/
void vdo_release_page_completion(struct vdo_completion *completion)
{
struct page_info *discard_info = NULL;
struct vdo_page_completion *page_completion = as_vdo_page_completion(completion);
struct vdo_page_cache *cache;
if (completion->result == VDO_SUCCESS) {
if (!validate_completed_page_or_enter_read_only_mode(page_completion, false))
return;
if (--page_completion->info->busy == 0)
discard_info = page_completion->info;
}
VDO_ASSERT_LOG_ONLY((page_completion->waiter.next_waiter == NULL),
"Page being released after leaving all queues");
page_completion->info = NULL;
cache = page_completion->cache;
assert_on_cache_thread(cache, __func__);
if (discard_info != NULL) {
if (discard_info->write_status == WRITE_STATUS_DEFERRED) {
discard_info->write_status = WRITE_STATUS_NORMAL;
launch_page_save(discard_info);
}
/*
* if there are excess requests for pages (that have not already started discards)
* we need to discard some page (which may be this one)
*/
discard_page_if_needed(cache);
}
}
/**
* load_page_for_completion() - Helper function to load a page as described by a VDO Page
* Completion.
*/
static void load_page_for_completion(struct page_info *info,
struct vdo_page_completion *vdo_page_comp)
{
int result;
vdo_waitq_enqueue_waiter(&info->waiting, &vdo_page_comp->waiter);
result = launch_page_load(info, vdo_page_comp->pbn);
if (result != VDO_SUCCESS) {
vdo_waitq_notify_all_waiters(&info->waiting,
complete_waiter_with_error, &result);
}
}
/**
* vdo_get_page() - Initialize a page completion and get a block map page.
* @page_completion: The vdo_page_completion to initialize.
* @zone: The block map zone of the desired page.
* @pbn: The absolute physical block of the desired page.
* @writable: Whether the page can be modified.
* @parent: The object to notify when the fetch is complete.
* @callback: The notification callback.
* @error_handler: The handler for fetch errors.
* @requeue: Whether we must requeue when notifying the parent.
*
* May cause another page to be discarded (potentially writing a dirty page) and the one nominated
* by the completion to be loaded from disk. When the callback is invoked, the page will be
* resident in the cache and marked busy. All callers must call vdo_release_page_completion()
* when they are done with the page to clear the busy mark.
*/
void vdo_get_page(struct vdo_page_completion *page_completion,
struct block_map_zone *zone, physical_block_number_t pbn,
bool writable, void *parent, vdo_action_fn callback,
vdo_action_fn error_handler, bool requeue)
{
struct vdo_page_cache *cache = &zone->page_cache;
struct vdo_completion *completion = &page_completion->completion;
struct page_info *info;
assert_on_cache_thread(cache, __func__);
VDO_ASSERT_LOG_ONLY((page_completion->waiter.next_waiter == NULL),
"New page completion was not already on a wait queue");
*page_completion = (struct vdo_page_completion) {
.pbn = pbn,
.writable = writable,
.cache = cache,
};
vdo_initialize_completion(completion, cache->vdo, VDO_PAGE_COMPLETION);
vdo_prepare_completion(completion, callback, error_handler,
cache->zone->thread_id, parent);
completion->requeue = requeue;
if (page_completion->writable && vdo_is_read_only(cache->vdo)) {
vdo_fail_completion(completion, VDO_READ_ONLY);
return;
}
if (page_completion->writable)
ADD_ONCE(cache->stats.write_count, 1);
else
ADD_ONCE(cache->stats.read_count, 1);
info = find_page(cache, page_completion->pbn);
if (info != NULL) {
/* The page is in the cache already. */
if ((info->write_status == WRITE_STATUS_DEFERRED) ||
is_incoming(info) ||
(is_outgoing(info) && page_completion->writable)) {
/* The page is unusable until it has finished I/O. */
ADD_ONCE(cache->stats.wait_for_page, 1);
vdo_waitq_enqueue_waiter(&info->waiting, &page_completion->waiter);
return;
}
if (is_valid(info)) {
/* The page is usable. */
ADD_ONCE(cache->stats.found_in_cache, 1);
if (!is_present(info))
ADD_ONCE(cache->stats.read_outgoing, 1);
update_lru(info);
info->busy++;
complete_with_page(info, page_completion);
return;
}
/* Something horrible has gone wrong. */
VDO_ASSERT_LOG_ONLY(false, "Info found in a usable state.");
}
/* The page must be fetched. */
info = find_free_page(cache);
if (info != NULL) {
ADD_ONCE(cache->stats.fetch_required, 1);
load_page_for_completion(info, page_completion);
return;
}
/* The page must wait for a page to be discarded. */
ADD_ONCE(cache->stats.discard_required, 1);
discard_page_for_completion(page_completion);
}
/**
* vdo_request_page_write() - Request that a VDO page be written out as soon as it is not busy.
* @completion: The vdo_page_completion containing the page.
*/
void vdo_request_page_write(struct vdo_completion *completion)
{
struct page_info *info;
struct vdo_page_completion *vdo_page_comp = as_vdo_page_completion(completion);
if (!validate_completed_page_or_enter_read_only_mode(vdo_page_comp, true))
return;
info = vdo_page_comp->info;
set_info_state(info, PS_DIRTY);
launch_page_save(info);
}
/**
* vdo_get_cached_page() - Get the block map page from a page completion.
* @completion: A vdo page completion whose callback has been called.
* @page_ptr: A pointer to hold the page
*
* Return: VDO_SUCCESS or an error
*/
int vdo_get_cached_page(struct vdo_completion *completion,
struct block_map_page **page_ptr)
{
int result;
struct vdo_page_completion *vpc;
vpc = as_vdo_page_completion(completion);
result = validate_completed_page(vpc, true);
if (result == VDO_SUCCESS)
*page_ptr = (struct block_map_page *) get_page_buffer(vpc->info);
return result;
}
/**
* vdo_invalidate_page_cache() - Invalidate all entries in the VDO page cache.
*
* There must not be any dirty pages in the cache.
*
* Return: A success or error code.
*/
int vdo_invalidate_page_cache(struct vdo_page_cache *cache)
{
struct page_info *info;
assert_on_cache_thread(cache, __func__);
/* Make sure we don't throw away any dirty pages. */
for (info = cache->infos; info < cache->infos + cache->page_count; info++) {
int result = VDO_ASSERT(!is_dirty(info), "cache must have no dirty pages");
if (result != VDO_SUCCESS)
return result;
}
/* Reset the page map by re-allocating it. */
vdo_int_map_free(vdo_forget(cache->page_map));
return vdo_int_map_create(cache->page_count, &cache->page_map);
}
/**
* get_tree_page_by_index() - Get the tree page for a given height and page index.
*
* Return: The requested page.
*/
static struct tree_page * __must_check get_tree_page_by_index(struct forest *forest,
root_count_t root_index,
height_t height,
page_number_t page_index)
{
page_number_t offset = 0;
size_t segment;
for (segment = 0; segment < forest->segments; segment++) {
page_number_t border = forest->boundaries[segment].levels[height - 1];
if (page_index < border) {
struct block_map_tree *tree = &forest->trees[root_index];
return &(tree->segments[segment].levels[height - 1][page_index - offset]);
}
offset = border;
}
return NULL;
}
/* Get the page referred to by the lock's tree slot at its current height. */
static inline struct tree_page *get_tree_page(const struct block_map_zone *zone,
const struct tree_lock *lock)
{
return get_tree_page_by_index(zone->block_map->forest, lock->root_index,
lock->height,
lock->tree_slots[lock->height].page_index);
}
/** vdo_copy_valid_page() - Validate and copy a buffer to a page. */
bool vdo_copy_valid_page(char *buffer, nonce_t nonce,
physical_block_number_t pbn,
struct block_map_page *page)
{
struct block_map_page *loaded = (struct block_map_page *) buffer;
enum block_map_page_validity validity =
vdo_validate_block_map_page(loaded, nonce, pbn);
if (validity == VDO_BLOCK_MAP_PAGE_VALID) {
memcpy(page, loaded, VDO_BLOCK_SIZE);
return true;
}
if (validity == VDO_BLOCK_MAP_PAGE_BAD) {
vdo_log_error_strerror(VDO_BAD_PAGE,
"Expected page %llu but got page %llu instead",
(unsigned long long) pbn,
(unsigned long long) vdo_get_block_map_page_pbn(loaded));
}
return false;
}
/**
* in_cyclic_range() - Check whether the given value is between the lower and upper bounds, within
* a cyclic range of values from 0 to (modulus - 1).
* @lower: The lowest value to accept.
* @value: The value to check.
* @upper: The highest value to accept.
* @modulus: The size of the cyclic space, no more than 2^15.
*
* The value and both bounds must be smaller than the modulus.
*
* Return: true if the value is in range.
*/
static bool in_cyclic_range(u16 lower, u16 value, u16 upper, u16 modulus)
{
if (value < lower)
value += modulus;
if (upper < lower)
upper += modulus;
return (value <= upper);
}
/**
* is_not_older() - Check whether a generation is strictly older than some other generation in the
* context of a zone's current generation range.
* @zone: The zone in which to do the comparison.
* @a: The generation in question.
* @b: The generation to compare to.
*
* Return: true if generation @a is not strictly older than generation @b in the context of @zone
*/
static bool __must_check is_not_older(struct block_map_zone *zone, u8 a, u8 b)
{
int result;
result = VDO_ASSERT((in_cyclic_range(zone->oldest_generation, a, zone->generation, 1 << 8) &&
in_cyclic_range(zone->oldest_generation, b, zone->generation, 1 << 8)),
"generation(s) %u, %u are out of range [%u, %u]",
a, b, zone->oldest_generation, zone->generation);
if (result != VDO_SUCCESS) {
enter_zone_read_only_mode(zone, result);
return true;
}
return in_cyclic_range(b, a, zone->generation, 1 << 8);
}
static void release_generation(struct block_map_zone *zone, u8 generation)
{
int result;
result = VDO_ASSERT((zone->dirty_page_counts[generation] > 0),
"dirty page count underflow for generation %u", generation);
if (result != VDO_SUCCESS) {
enter_zone_read_only_mode(zone, result);
return;
}
zone->dirty_page_counts[generation]--;
while ((zone->dirty_page_counts[zone->oldest_generation] == 0) &&
(zone->oldest_generation != zone->generation))
zone->oldest_generation++;
}
static void set_generation(struct block_map_zone *zone, struct tree_page *page,
u8 new_generation)
{
u32 new_count;
int result;
bool decrement_old = vdo_waiter_is_waiting(&page->waiter);
u8 old_generation = page->generation;
if (decrement_old && (old_generation == new_generation))
return;
page->generation = new_generation;
new_count = ++zone->dirty_page_counts[new_generation];
result = VDO_ASSERT((new_count != 0), "dirty page count overflow for generation %u",
new_generation);
if (result != VDO_SUCCESS) {
enter_zone_read_only_mode(zone, result);
return;
}
if (decrement_old)
release_generation(zone, old_generation);
}
static void write_page(struct tree_page *tree_page, struct pooled_vio *vio);
/* Implements waiter_callback_fn */
static void write_page_callback(struct vdo_waiter *waiter, void *context)
{
write_page(container_of(waiter, struct tree_page, waiter), context);
}
static void acquire_vio(struct vdo_waiter *waiter, struct block_map_zone *zone)
{
waiter->callback = write_page_callback;
acquire_vio_from_pool(zone->vio_pool, waiter);
}
/* Return: true if all possible generations were not already active */
static bool attempt_increment(struct block_map_zone *zone)
{
u8 generation = zone->generation + 1;
if (zone->oldest_generation == generation)
return false;
zone->generation = generation;
return true;
}
/* Launches a flush if one is not already in progress. */
static void enqueue_page(struct tree_page *page, struct block_map_zone *zone)
{
if ((zone->flusher == NULL) && attempt_increment(zone)) {
zone->flusher = page;
acquire_vio(&page->waiter, zone);
return;
}
vdo_waitq_enqueue_waiter(&zone->flush_waiters, &page->waiter);
}
static void write_page_if_not_dirtied(struct vdo_waiter *waiter, void *context)
{
struct tree_page *page = container_of(waiter, struct tree_page, waiter);
struct write_if_not_dirtied_context *write_context = context;
if (page->generation == write_context->generation) {
acquire_vio(waiter, write_context->zone);
return;
}
enqueue_page(page, write_context->zone);
}
static void return_to_pool(struct block_map_zone *zone, struct pooled_vio *vio)
{
return_vio_to_pool(zone->vio_pool, vio);
check_for_drain_complete(zone);
}
/* This callback is registered in write_initialized_page(). */
static void finish_page_write(struct vdo_completion *completion)
{
bool dirty;
struct vio *vio = as_vio(completion);
struct pooled_vio *pooled = container_of(vio, struct pooled_vio, vio);
struct tree_page *page = completion->parent;
struct block_map_zone *zone = pooled->context;
vdo_release_recovery_journal_block_reference(zone->block_map->journal,
page->writing_recovery_lock,
VDO_ZONE_TYPE_LOGICAL,
zone->zone_number);
dirty = (page->writing_generation != page->generation);
release_generation(zone, page->writing_generation);
page->writing = false;
if (zone->flusher == page) {
struct write_if_not_dirtied_context context = {
.zone = zone,
.generation = page->writing_generation,
};
vdo_waitq_notify_all_waiters(&zone->flush_waiters,
write_page_if_not_dirtied, &context);
if (dirty && attempt_increment(zone)) {
write_page(page, pooled);
return;
}
zone->flusher = NULL;
}
if (dirty) {
enqueue_page(page, zone);
} else if ((zone->flusher == NULL) && vdo_waitq_has_waiters(&zone->flush_waiters) &&
attempt_increment(zone)) {
zone->flusher = container_of(vdo_waitq_dequeue_waiter(&zone->flush_waiters),
struct tree_page, waiter);
write_page(zone->flusher, pooled);
return;
}
return_to_pool(zone, pooled);
}
static void handle_write_error(struct vdo_completion *completion)
{
int result = completion->result;
struct vio *vio = as_vio(completion);
struct pooled_vio *pooled = container_of(vio, struct pooled_vio, vio);
struct block_map_zone *zone = pooled->context;
vio_record_metadata_io_error(vio);
enter_zone_read_only_mode(zone, result);
return_to_pool(zone, pooled);
}
static void write_page_endio(struct bio *bio);
static void write_initialized_page(struct vdo_completion *completion)
{
struct vio *vio = as_vio(completion);
struct pooled_vio *pooled = container_of(vio, struct pooled_vio, vio);
struct block_map_zone *zone = pooled->context;
struct tree_page *tree_page = completion->parent;
struct block_map_page *page = (struct block_map_page *) vio->data;
blk_opf_t operation = REQ_OP_WRITE | REQ_PRIO;
/*
* Now that we know the page has been written at least once, mark the copy we are writing
* as initialized.
*/
page->header.initialized = true;
if (zone->flusher == tree_page)
operation |= REQ_PREFLUSH;
vdo_submit_metadata_vio(vio, vdo_get_block_map_page_pbn(page),
write_page_endio, handle_write_error,
operation);
}
static void write_page_endio(struct bio *bio)
{
struct pooled_vio *vio = bio->bi_private;
struct block_map_zone *zone = vio->context;
struct block_map_page *page = (struct block_map_page *) vio->vio.data;
continue_vio_after_io(&vio->vio,
(page->header.initialized ?
finish_page_write : write_initialized_page),
zone->thread_id);
}
static void write_page(struct tree_page *tree_page, struct pooled_vio *vio)
{
struct vdo_completion *completion = &vio->vio.completion;
struct block_map_zone *zone = vio->context;
struct block_map_page *page = vdo_as_block_map_page(tree_page);
if ((zone->flusher != tree_page) &&
is_not_older(zone, tree_page->generation, zone->generation)) {
/*
* This page was re-dirtied after the last flush was issued, hence we need to do
* another flush.
*/
enqueue_page(tree_page, zone);
return_to_pool(zone, vio);
return;
}
completion->parent = tree_page;
memcpy(vio->vio.data, tree_page->page_buffer, VDO_BLOCK_SIZE);
completion->callback_thread_id = zone->thread_id;
tree_page->writing = true;
tree_page->writing_generation = tree_page->generation;
tree_page->writing_recovery_lock = tree_page->recovery_lock;
/* Clear this now so that we know this page is not on any dirty list. */
tree_page->recovery_lock = 0;
/*
* We've already copied the page into the vio which will write it, so if it was not yet
* initialized, the first write will indicate that (for torn write protection). It is now
* safe to mark it as initialized in memory since if the write fails, the in memory state
* will become irrelevant.
*/
if (page->header.initialized) {
write_initialized_page(completion);
return;
}
page->header.initialized = true;
vdo_submit_metadata_vio(&vio->vio, vdo_get_block_map_page_pbn(page),
write_page_endio, handle_write_error,
REQ_OP_WRITE | REQ_PRIO);
}
/* Release a lock on a page which was being loaded or allocated. */
static void release_page_lock(struct data_vio *data_vio, char *what)
{
struct block_map_zone *zone;
struct tree_lock *lock_holder;
struct tree_lock *lock = &data_vio->tree_lock;
VDO_ASSERT_LOG_ONLY(lock->locked,
"release of unlocked block map page %s for key %llu in tree %u",
what, (unsigned long long) lock->key, lock->root_index);
zone = data_vio->logical.zone->block_map_zone;
lock_holder = vdo_int_map_remove(zone->loading_pages, lock->key);
VDO_ASSERT_LOG_ONLY((lock_holder == lock),
"block map page %s mismatch for key %llu in tree %u",
what, (unsigned long long) lock->key, lock->root_index);
lock->locked = false;
}
static void finish_lookup(struct data_vio *data_vio, int result)
{
data_vio->tree_lock.height = 0;
--data_vio->logical.zone->block_map_zone->active_lookups;
set_data_vio_logical_callback(data_vio, continue_data_vio_with_block_map_slot);
data_vio->vio.completion.error_handler = handle_data_vio_error;
continue_data_vio_with_error(data_vio, result);
}
static void abort_lookup_for_waiter(struct vdo_waiter *waiter, void *context)
{
struct data_vio *data_vio = vdo_waiter_as_data_vio(waiter);
int result = *((int *) context);
if (!data_vio->write) {
if (result == VDO_NO_SPACE)
result = VDO_SUCCESS;
} else if (result != VDO_NO_SPACE) {
result = VDO_READ_ONLY;
}
finish_lookup(data_vio, result);
}
static void abort_lookup(struct data_vio *data_vio, int result, char *what)
{
if (result != VDO_NO_SPACE)
enter_zone_read_only_mode(data_vio->logical.zone->block_map_zone, result);
if (data_vio->tree_lock.locked) {
release_page_lock(data_vio, what);
vdo_waitq_notify_all_waiters(&data_vio->tree_lock.waiters,
abort_lookup_for_waiter,
&result);
}
finish_lookup(data_vio, result);
}
static void abort_load(struct data_vio *data_vio, int result)
{
abort_lookup(data_vio, result, "load");
}
static bool __must_check is_invalid_tree_entry(const struct vdo *vdo,
const struct data_location *mapping,
height_t height)
{
if (!vdo_is_valid_location(mapping) ||
vdo_is_state_compressed(mapping->state) ||
(vdo_is_mapped_location(mapping) && (mapping->pbn == VDO_ZERO_BLOCK)))
return true;
/* Roots aren't physical data blocks, so we can't check their PBNs. */
if (height == VDO_BLOCK_MAP_TREE_HEIGHT)
return false;
return !vdo_is_physical_data_block(vdo->depot, mapping->pbn);
}
static void load_block_map_page(struct block_map_zone *zone, struct data_vio *data_vio);
static void allocate_block_map_page(struct block_map_zone *zone,
struct data_vio *data_vio);
static void continue_with_loaded_page(struct data_vio *data_vio,
struct block_map_page *page)
{
struct tree_lock *lock = &data_vio->tree_lock;
struct block_map_tree_slot slot = lock->tree_slots[lock->height];
struct data_location mapping =
vdo_unpack_block_map_entry(&page->entries[slot.block_map_slot.slot]);
if (is_invalid_tree_entry(vdo_from_data_vio(data_vio), &mapping, lock->height)) {
vdo_log_error_strerror(VDO_BAD_MAPPING,
"Invalid block map tree PBN: %llu with state %u for page index %u at height %u",
(unsigned long long) mapping.pbn, mapping.state,
lock->tree_slots[lock->height - 1].page_index,
lock->height - 1);
abort_load(data_vio, VDO_BAD_MAPPING);
return;
}
if (!vdo_is_mapped_location(&mapping)) {
/* The page we need is unallocated */
allocate_block_map_page(data_vio->logical.zone->block_map_zone,
data_vio);
return;
}
lock->tree_slots[lock->height - 1].block_map_slot.pbn = mapping.pbn;
if (lock->height == 1) {
finish_lookup(data_vio, VDO_SUCCESS);
return;
}
/* We know what page we need to load next */
load_block_map_page(data_vio->logical.zone->block_map_zone, data_vio);
}
static void continue_load_for_waiter(struct vdo_waiter *waiter, void *context)
{
struct data_vio *data_vio = vdo_waiter_as_data_vio(waiter);
data_vio->tree_lock.height--;
continue_with_loaded_page(data_vio, context);
}
static void finish_block_map_page_load(struct vdo_completion *completion)
{
physical_block_number_t pbn;
struct tree_page *tree_page;
struct block_map_page *page;
nonce_t nonce;
struct vio *vio = as_vio(completion);
struct pooled_vio *pooled = vio_as_pooled_vio(vio);
struct data_vio *data_vio = completion->parent;
struct block_map_zone *zone = pooled->context;
struct tree_lock *tree_lock = &data_vio->tree_lock;
tree_lock->height--;
pbn = tree_lock->tree_slots[tree_lock->height].block_map_slot.pbn;
tree_page = get_tree_page(zone, tree_lock);
page = (struct block_map_page *) tree_page->page_buffer;
nonce = zone->block_map->nonce;
if (!vdo_copy_valid_page(vio->data, nonce, pbn, page))
vdo_format_block_map_page(page, nonce, pbn, false);
return_vio_to_pool(zone->vio_pool, pooled);
/* Release our claim to the load and wake any waiters */
release_page_lock(data_vio, "load");
vdo_waitq_notify_all_waiters(&tree_lock->waiters, continue_load_for_waiter, page);
continue_with_loaded_page(data_vio, page);
}
static void handle_io_error(struct vdo_completion *completion)
{
int result = completion->result;
struct vio *vio = as_vio(completion);
struct pooled_vio *pooled = container_of(vio, struct pooled_vio, vio);
struct data_vio *data_vio = completion->parent;
struct block_map_zone *zone = pooled->context;
vio_record_metadata_io_error(vio);
return_vio_to_pool(zone->vio_pool, pooled);
abort_load(data_vio, result);
}
static void load_page_endio(struct bio *bio)
{
struct vio *vio = bio->bi_private;
struct data_vio *data_vio = vio->completion.parent;
continue_vio_after_io(vio, finish_block_map_page_load,
data_vio->logical.zone->thread_id);
}
static void load_page(struct vdo_waiter *waiter, void *context)
{
struct pooled_vio *pooled = context;
struct data_vio *data_vio = vdo_waiter_as_data_vio(waiter);
struct tree_lock *lock = &data_vio->tree_lock;
physical_block_number_t pbn = lock->tree_slots[lock->height - 1].block_map_slot.pbn;
pooled->vio.completion.parent = data_vio;
vdo_submit_metadata_vio(&pooled->vio, pbn, load_page_endio,
handle_io_error, REQ_OP_READ | REQ_PRIO);
}
/*
* If the page is already locked, queue up to wait for the lock to be released. If the lock is
* acquired, @data_vio->tree_lock.locked will be true.
*/
static int attempt_page_lock(struct block_map_zone *zone, struct data_vio *data_vio)
{
int result;
struct tree_lock *lock_holder;
struct tree_lock *lock = &data_vio->tree_lock;
height_t height = lock->height;
struct block_map_tree_slot tree_slot = lock->tree_slots[height];
union page_key key;
key.descriptor = (struct page_descriptor) {
.root_index = lock->root_index,
.height = height,
.page_index = tree_slot.page_index,
.slot = tree_slot.block_map_slot.slot,
};
lock->key = key.key;
result = vdo_int_map_put(zone->loading_pages, lock->key,
lock, false, (void **) &lock_holder);
if (result != VDO_SUCCESS)
return result;
if (lock_holder == NULL) {
/* We got the lock */
data_vio->tree_lock.locked = true;
return VDO_SUCCESS;
}
/* Someone else is loading or allocating the page we need */
vdo_waitq_enqueue_waiter(&lock_holder->waiters, &data_vio->waiter);
return VDO_SUCCESS;
}
/* Load a block map tree page from disk, for the next level in the data vio tree lock. */
static void load_block_map_page(struct block_map_zone *zone, struct data_vio *data_vio)
{
int result;
result = attempt_page_lock(zone, data_vio);
if (result != VDO_SUCCESS) {
abort_load(data_vio, result);
return;
}
if (data_vio->tree_lock.locked) {
data_vio->waiter.callback = load_page;
acquire_vio_from_pool(zone->vio_pool, &data_vio->waiter);
}
}
static void allocation_failure(struct vdo_completion *completion)
{
struct data_vio *data_vio = as_data_vio(completion);
if (vdo_requeue_completion_if_needed(completion,
data_vio->logical.zone->thread_id))
return;
abort_lookup(data_vio, completion->result, "allocation");
}
static void continue_allocation_for_waiter(struct vdo_waiter *waiter, void *context)
{
struct data_vio *data_vio = vdo_waiter_as_data_vio(waiter);
struct tree_lock *tree_lock = &data_vio->tree_lock;
physical_block_number_t pbn = *((physical_block_number_t *) context);
tree_lock->height--;
data_vio->tree_lock.tree_slots[tree_lock->height].block_map_slot.pbn = pbn;
if (tree_lock->height == 0) {
finish_lookup(data_vio, VDO_SUCCESS);
return;
}
allocate_block_map_page(data_vio->logical.zone->block_map_zone, data_vio);
}
/** expire_oldest_list() - Expire the oldest list. */
static void expire_oldest_list(struct dirty_lists *dirty_lists)
{
block_count_t i = dirty_lists->offset++;
dirty_lists->oldest_period++;
if (!list_empty(&dirty_lists->eras[i][VDO_TREE_PAGE])) {
list_splice_tail_init(&dirty_lists->eras[i][VDO_TREE_PAGE],
&dirty_lists->expired[VDO_TREE_PAGE]);
}
if (!list_empty(&dirty_lists->eras[i][VDO_CACHE_PAGE])) {
list_splice_tail_init(&dirty_lists->eras[i][VDO_CACHE_PAGE],
&dirty_lists->expired[VDO_CACHE_PAGE]);
}
if (dirty_lists->offset == dirty_lists->maximum_age)
dirty_lists->offset = 0;
}
/** update_period() - Update the dirty_lists period if necessary. */
static void update_period(struct dirty_lists *dirty, sequence_number_t period)
{
while (dirty->next_period <= period) {
if ((dirty->next_period - dirty->oldest_period) == dirty->maximum_age)
expire_oldest_list(dirty);
dirty->next_period++;
}
}
/** write_expired_elements() - Write out the expired list. */
static void write_expired_elements(struct block_map_zone *zone)
{
struct tree_page *page, *ttmp;
struct page_info *info, *ptmp;
struct list_head *expired;
u8 generation = zone->generation;
expired = &zone->dirty_lists->expired[VDO_TREE_PAGE];
list_for_each_entry_safe(page, ttmp, expired, entry) {
int result;
list_del_init(&page->entry);
result = VDO_ASSERT(!vdo_waiter_is_waiting(&page->waiter),
"Newly expired page not already waiting to write");
if (result != VDO_SUCCESS) {
enter_zone_read_only_mode(zone, result);
continue;
}
set_generation(zone, page, generation);
if (!page->writing)
enqueue_page(page, zone);
}
expired = &zone->dirty_lists->expired[VDO_CACHE_PAGE];
list_for_each_entry_safe(info, ptmp, expired, state_entry) {
list_del_init(&info->state_entry);
schedule_page_save(info);
}
save_pages(&zone->page_cache);
}
/**
* add_to_dirty_lists() - Add an element to the dirty lists.
* @zone: The zone in which we are operating.
* @entry: The list entry of the element to add.
* @type: The type of page.
* @old_period: The period in which the element was previously dirtied, or 0 if it was not dirty.
* @new_period: The period in which the element has now been dirtied, or 0 if it does not hold a
* lock.
*/
static void add_to_dirty_lists(struct block_map_zone *zone,
struct list_head *entry,
enum block_map_page_type type,
sequence_number_t old_period,
sequence_number_t new_period)
{
struct dirty_lists *dirty_lists = zone->dirty_lists;
if ((old_period == new_period) || ((old_period != 0) && (old_period < new_period)))
return;
if (new_period < dirty_lists->oldest_period) {
list_move_tail(entry, &dirty_lists->expired[type]);
} else {
update_period(dirty_lists, new_period);
list_move_tail(entry,
&dirty_lists->eras[new_period % dirty_lists->maximum_age][type]);
}
write_expired_elements(zone);
}
/*
* Record the allocation in the tree and wake any waiters now that the write lock has been
* released.
*/
static void finish_block_map_allocation(struct vdo_completion *completion)
{
physical_block_number_t pbn;
struct tree_page *tree_page;
struct block_map_page *page;
sequence_number_t old_lock;
struct data_vio *data_vio = as_data_vio(completion);
struct block_map_zone *zone = data_vio->logical.zone->block_map_zone;
struct tree_lock *tree_lock = &data_vio->tree_lock;
height_t height = tree_lock->height;
assert_data_vio_in_logical_zone(data_vio);
tree_page = get_tree_page(zone, tree_lock);
pbn = tree_lock->tree_slots[height - 1].block_map_slot.pbn;
/* Record the allocation. */
page = (struct block_map_page *) tree_page->page_buffer;
old_lock = tree_page->recovery_lock;
vdo_update_block_map_page(page, data_vio, pbn,
VDO_MAPPING_STATE_UNCOMPRESSED,
&tree_page->recovery_lock);
if (vdo_waiter_is_waiting(&tree_page->waiter)) {
/* This page is waiting to be written out. */
if (zone->flusher != tree_page) {
/*
* The outstanding flush won't cover the update we just made,
* so mark the page as needing another flush.
*/
set_generation(zone, tree_page, zone->generation);
}
} else {
/* Put the page on a dirty list */
if (old_lock == 0)
INIT_LIST_HEAD(&tree_page->entry);
add_to_dirty_lists(zone, &tree_page->entry, VDO_TREE_PAGE,
old_lock, tree_page->recovery_lock);
}
tree_lock->height--;
if (height > 1) {
/* Format the interior node we just allocated (in memory). */
tree_page = get_tree_page(zone, tree_lock);
vdo_format_block_map_page(tree_page->page_buffer,
zone->block_map->nonce,
pbn, false);
}
/* Release our claim to the allocation and wake any waiters */
release_page_lock(data_vio, "allocation");
vdo_waitq_notify_all_waiters(&tree_lock->waiters,
continue_allocation_for_waiter, &pbn);
if (tree_lock->height == 0) {
finish_lookup(data_vio, VDO_SUCCESS);
return;
}
allocate_block_map_page(zone, data_vio);
}
static void release_block_map_write_lock(struct vdo_completion *completion)
{
struct data_vio *data_vio = as_data_vio(completion);
assert_data_vio_in_allocated_zone(data_vio);
release_data_vio_allocation_lock(data_vio, true);
launch_data_vio_logical_callback(data_vio, finish_block_map_allocation);
}
/*
* Newly allocated block map pages are set to have to MAXIMUM_REFERENCES after they are journaled,
* to prevent deduplication against the block after we release the write lock on it, but before we
* write out the page.
*/
static void set_block_map_page_reference_count(struct vdo_completion *completion)
{
struct data_vio *data_vio = as_data_vio(completion);
assert_data_vio_in_allocated_zone(data_vio);
completion->callback = release_block_map_write_lock;
vdo_modify_reference_count(completion, &data_vio->increment_updater);
}
static void journal_block_map_allocation(struct vdo_completion *completion)
{
struct data_vio *data_vio = as_data_vio(completion);
assert_data_vio_in_journal_zone(data_vio);
set_data_vio_allocated_zone_callback(data_vio,
set_block_map_page_reference_count);
vdo_add_recovery_journal_entry(completion->vdo->recovery_journal, data_vio);
}
static void allocate_block(struct vdo_completion *completion)
{
struct data_vio *data_vio = as_data_vio(completion);
struct tree_lock *lock = &data_vio->tree_lock;
physical_block_number_t pbn;
assert_data_vio_in_allocated_zone(data_vio);
if (!vdo_allocate_block_in_zone(data_vio))
return;
pbn = data_vio->allocation.pbn;
lock->tree_slots[lock->height - 1].block_map_slot.pbn = pbn;
data_vio->increment_updater = (struct reference_updater) {
.operation = VDO_JOURNAL_BLOCK_MAP_REMAPPING,
.increment = true,
.zpbn = {
.pbn = pbn,
.state = VDO_MAPPING_STATE_UNCOMPRESSED,
},
.lock = data_vio->allocation.lock,
};
launch_data_vio_journal_callback(data_vio, journal_block_map_allocation);
}
static void allocate_block_map_page(struct block_map_zone *zone,
struct data_vio *data_vio)
{
int result;
if (!data_vio->write || data_vio->is_discard) {
/* This is a pure read or a discard, so there's nothing left to do here. */
finish_lookup(data_vio, VDO_SUCCESS);
return;
}
result = attempt_page_lock(zone, data_vio);
if (result != VDO_SUCCESS) {
abort_lookup(data_vio, result, "allocation");
return;
}
if (!data_vio->tree_lock.locked)
return;
data_vio_allocate_data_block(data_vio, VIO_BLOCK_MAP_WRITE_LOCK,
allocate_block, allocation_failure);
}
/**
* vdo_find_block_map_slot() - Find the block map slot in which the block map entry for a data_vio
* resides and cache that result in the data_vio.
*
* All ancestors in the tree will be allocated or loaded, as needed.
*/
void vdo_find_block_map_slot(struct data_vio *data_vio)
{
page_number_t page_index;
struct block_map_tree_slot tree_slot;
struct data_location mapping;
struct block_map_page *page = NULL;
struct tree_lock *lock = &data_vio->tree_lock;
struct block_map_zone *zone = data_vio->logical.zone->block_map_zone;
zone->active_lookups++;
if (vdo_is_state_draining(&zone->state)) {
finish_lookup(data_vio, VDO_SHUTTING_DOWN);
return;
}
lock->tree_slots[0].block_map_slot.slot =
data_vio->logical.lbn % VDO_BLOCK_MAP_ENTRIES_PER_PAGE;
page_index = (lock->tree_slots[0].page_index / zone->block_map->root_count);
tree_slot = (struct block_map_tree_slot) {
.page_index = page_index / VDO_BLOCK_MAP_ENTRIES_PER_PAGE,
.block_map_slot = {
.pbn = 0,
.slot = page_index % VDO_BLOCK_MAP_ENTRIES_PER_PAGE,
},
};
for (lock->height = 1; lock->height <= VDO_BLOCK_MAP_TREE_HEIGHT; lock->height++) {
physical_block_number_t pbn;
lock->tree_slots[lock->height] = tree_slot;
page = (struct block_map_page *) (get_tree_page(zone, lock)->page_buffer);
pbn = vdo_get_block_map_page_pbn(page);
if (pbn != VDO_ZERO_BLOCK) {
lock->tree_slots[lock->height].block_map_slot.pbn = pbn;
break;
}
/* Calculate the index and slot for the next level. */
tree_slot.block_map_slot.slot =
tree_slot.page_index % VDO_BLOCK_MAP_ENTRIES_PER_PAGE;
tree_slot.page_index = tree_slot.page_index / VDO_BLOCK_MAP_ENTRIES_PER_PAGE;
}
/* The page at this height has been allocated and loaded. */
mapping = vdo_unpack_block_map_entry(&page->entries[tree_slot.block_map_slot.slot]);
if (is_invalid_tree_entry(vdo_from_data_vio(data_vio), &mapping, lock->height)) {
vdo_log_error_strerror(VDO_BAD_MAPPING,
"Invalid block map tree PBN: %llu with state %u for page index %u at height %u",
(unsigned long long) mapping.pbn, mapping.state,
lock->tree_slots[lock->height - 1].page_index,
lock->height - 1);
abort_load(data_vio, VDO_BAD_MAPPING);
return;
}
if (!vdo_is_mapped_location(&mapping)) {
/* The page we want one level down has not been allocated, so allocate it. */
allocate_block_map_page(zone, data_vio);
return;
}
lock->tree_slots[lock->height - 1].block_map_slot.pbn = mapping.pbn;
if (lock->height == 1) {
/* This is the ultimate block map page, so we're done */
finish_lookup(data_vio, VDO_SUCCESS);
return;
}
/* We know what page we need to load. */
load_block_map_page(zone, data_vio);
}
/*
* Find the PBN of a leaf block map page. This method may only be used after all allocated tree
* pages have been loaded, otherwise, it may give the wrong answer (0).
*/
physical_block_number_t vdo_find_block_map_page_pbn(struct block_map *map,
page_number_t page_number)
{
struct data_location mapping;
struct tree_page *tree_page;
struct block_map_page *page;
root_count_t root_index = page_number % map->root_count;
page_number_t page_index = page_number / map->root_count;
slot_number_t slot = page_index % VDO_BLOCK_MAP_ENTRIES_PER_PAGE;
page_index /= VDO_BLOCK_MAP_ENTRIES_PER_PAGE;
tree_page = get_tree_page_by_index(map->forest, root_index, 1, page_index);
page = (struct block_map_page *) tree_page->page_buffer;
if (!page->header.initialized)
return VDO_ZERO_BLOCK;
mapping = vdo_unpack_block_map_entry(&page->entries[slot]);
if (!vdo_is_valid_location(&mapping) || vdo_is_state_compressed(mapping.state))
return VDO_ZERO_BLOCK;
return mapping.pbn;
}
/*
* Write a tree page or indicate that it has been re-dirtied if it is already being written. This
* method is used when correcting errors in the tree during read-only rebuild.
*/
void vdo_write_tree_page(struct tree_page *page, struct block_map_zone *zone)
{
bool waiting = vdo_waiter_is_waiting(&page->waiter);
if (waiting && (zone->flusher == page))
return;
set_generation(zone, page, zone->generation);
if (waiting || page->writing)
return;
enqueue_page(page, zone);
}
static int make_segment(struct forest *old_forest, block_count_t new_pages,
struct boundary *new_boundary, struct forest *forest)
{
size_t index = (old_forest == NULL) ? 0 : old_forest->segments;
struct tree_page *page_ptr;
page_count_t segment_sizes[VDO_BLOCK_MAP_TREE_HEIGHT];
height_t height;
root_count_t root;
int result;
forest->segments = index + 1;
result = vdo_allocate(forest->segments, struct boundary,
"forest boundary array", &forest->boundaries);
if (result != VDO_SUCCESS)
return result;
result = vdo_allocate(forest->segments, struct tree_page *,
"forest page pointers", &forest->pages);
if (result != VDO_SUCCESS)
return result;
result = vdo_allocate(new_pages, struct tree_page,
"new forest pages", &forest->pages[index]);
if (result != VDO_SUCCESS)
return result;
if (index > 0) {
memcpy(forest->boundaries, old_forest->boundaries,
index * sizeof(struct boundary));
memcpy(forest->pages, old_forest->pages,
index * sizeof(struct tree_page *));
}
memcpy(&(forest->boundaries[index]), new_boundary, sizeof(struct boundary));
for (height = 0; height < VDO_BLOCK_MAP_TREE_HEIGHT; height++) {
segment_sizes[height] = new_boundary->levels[height];
if (index > 0)
segment_sizes[height] -= old_forest->boundaries[index - 1].levels[height];
}
page_ptr = forest->pages[index];
for (root = 0; root < forest->map->root_count; root++) {
struct block_map_tree_segment *segment;
struct block_map_tree *tree = &(forest->trees[root]);
height_t height;
int result = vdo_allocate(forest->segments,
struct block_map_tree_segment,
"tree root segments", &tree->segments);
if (result != VDO_SUCCESS)
return result;
if (index > 0) {
memcpy(tree->segments, old_forest->trees[root].segments,
index * sizeof(struct block_map_tree_segment));
}
segment = &(tree->segments[index]);
for (height = 0; height < VDO_BLOCK_MAP_TREE_HEIGHT; height++) {
if (segment_sizes[height] == 0)
continue;
segment->levels[height] = page_ptr;
if (height == (VDO_BLOCK_MAP_TREE_HEIGHT - 1)) {
/* Record the root. */
struct block_map_page *page =
vdo_format_block_map_page(page_ptr->page_buffer,
forest->map->nonce,
VDO_INVALID_PBN, true);
page->entries[0] =
vdo_pack_block_map_entry(forest->map->root_origin + root,
VDO_MAPPING_STATE_UNCOMPRESSED);
}
page_ptr += segment_sizes[height];
}
}
return VDO_SUCCESS;
}
static void deforest(struct forest *forest, size_t first_page_segment)
{
root_count_t root;
if (forest->pages != NULL) {
size_t segment;
for (segment = first_page_segment; segment < forest->segments; segment++)
vdo_free(forest->pages[segment]);
vdo_free(forest->pages);
}
for (root = 0; root < forest->map->root_count; root++)
vdo_free(forest->trees[root].segments);
vdo_free(forest->boundaries);
vdo_free(forest);
}
/**
* make_forest() - Make a collection of trees for a block_map, expanding the existing forest if
* there is one.
* @entries: The number of entries the block map will hold.
*
* Return: VDO_SUCCESS or an error.
*/
static int make_forest(struct block_map *map, block_count_t entries)
{
struct forest *forest, *old_forest = map->forest;
struct boundary new_boundary, *old_boundary = NULL;
block_count_t new_pages;
int result;
if (old_forest != NULL)
old_boundary = &(old_forest->boundaries[old_forest->segments - 1]);
new_pages = vdo_compute_new_forest_pages(map->root_count, old_boundary,
entries, &new_boundary);
if (new_pages == 0) {
map->next_entry_count = entries;
return VDO_SUCCESS;
}
result = vdo_allocate_extended(struct forest, map->root_count,
struct block_map_tree, __func__,
&forest);
if (result != VDO_SUCCESS)
return result;
forest->map = map;
result = make_segment(old_forest, new_pages, &new_boundary, forest);
if (result != VDO_SUCCESS) {
deforest(forest, forest->segments - 1);
return result;
}
map->next_forest = forest;
map->next_entry_count = entries;
return VDO_SUCCESS;
}
/**
* replace_forest() - Replace a block_map's forest with the already-prepared larger forest.
*/
static void replace_forest(struct block_map *map)
{
if (map->next_forest != NULL) {
if (map->forest != NULL)
deforest(map->forest, map->forest->segments);
map->forest = vdo_forget(map->next_forest);
}
map->entry_count = map->next_entry_count;
map->next_entry_count = 0;
}
/**
* finish_cursor() - Finish the traversal of a single tree. If it was the last cursor, finish the
* traversal.
*/
static void finish_cursor(struct cursor *cursor)
{
struct cursors *cursors = cursor->parent;
struct vdo_completion *completion = cursors->completion;
return_vio_to_pool(cursors->pool, vdo_forget(cursor->vio));
if (--cursors->active_roots > 0)
return;
vdo_free(cursors);
vdo_finish_completion(completion);
}
static void traverse(struct cursor *cursor);
/**
* continue_traversal() - Continue traversing a block map tree.
* @completion: The VIO doing a read or write.
*/
static void continue_traversal(struct vdo_completion *completion)
{
vio_record_metadata_io_error(as_vio(completion));
traverse(completion->parent);
}
/**
* finish_traversal_load() - Continue traversing a block map tree now that a page has been loaded.
* @completion: The VIO doing the read.
*/
static void finish_traversal_load(struct vdo_completion *completion)
{
struct cursor *cursor = completion->parent;
height_t height = cursor->height;
struct cursor_level *level = &cursor->levels[height];
struct tree_page *tree_page =
&(cursor->tree->segments[0].levels[height][level->page_index]);
struct block_map_page *page = (struct block_map_page *) tree_page->page_buffer;
vdo_copy_valid_page(cursor->vio->vio.data,
cursor->parent->zone->block_map->nonce,
pbn_from_vio_bio(cursor->vio->vio.bio), page);
traverse(cursor);
}
static void traversal_endio(struct bio *bio)
{
struct vio *vio = bio->bi_private;
struct cursor *cursor = vio->completion.parent;
continue_vio_after_io(vio, finish_traversal_load,
cursor->parent->zone->thread_id);
}
/**
* traverse() - Traverse a single block map tree.
*
* This is the recursive heart of the traversal process.
*/
static void traverse(struct cursor *cursor)
{
for (; cursor->height < VDO_BLOCK_MAP_TREE_HEIGHT; cursor->height++) {
height_t height = cursor->height;
struct cursor_level *level = &cursor->levels[height];
struct tree_page *tree_page =
&(cursor->tree->segments[0].levels[height][level->page_index]);
struct block_map_page *page = (struct block_map_page *) tree_page->page_buffer;
if (!page->header.initialized)
continue;
for (; level->slot < VDO_BLOCK_MAP_ENTRIES_PER_PAGE; level->slot++) {
struct cursor_level *next_level;
page_number_t entry_index =
(VDO_BLOCK_MAP_ENTRIES_PER_PAGE * level->page_index) + level->slot;
struct data_location location =
vdo_unpack_block_map_entry(&page->entries[level->slot]);
if (!vdo_is_valid_location(&location)) {
/* This entry is invalid, so remove it from the page. */
page->entries[level->slot] = UNMAPPED_BLOCK_MAP_ENTRY;
vdo_write_tree_page(tree_page, cursor->parent->zone);
continue;
}
if (!vdo_is_mapped_location(&location))
continue;
/* Erase mapped entries past the end of the logical space. */
if (entry_index >= cursor->boundary.levels[height]) {
page->entries[level->slot] = UNMAPPED_BLOCK_MAP_ENTRY;
vdo_write_tree_page(tree_page, cursor->parent->zone);
continue;
}
if (cursor->height < VDO_BLOCK_MAP_TREE_HEIGHT - 1) {
int result = cursor->parent->entry_callback(location.pbn,
cursor->parent->completion);
if (result != VDO_SUCCESS) {
page->entries[level->slot] = UNMAPPED_BLOCK_MAP_ENTRY;
vdo_write_tree_page(tree_page, cursor->parent->zone);
continue;
}
}
if (cursor->height == 0)
continue;
cursor->height--;
next_level = &cursor->levels[cursor->height];
next_level->page_index = entry_index;
next_level->slot = 0;
level->slot++;
vdo_submit_metadata_vio(&cursor->vio->vio, location.pbn,
traversal_endio, continue_traversal,
REQ_OP_READ | REQ_PRIO);
return;
}
}
finish_cursor(cursor);
}
/**
* launch_cursor() - Start traversing a single block map tree now that the cursor has a VIO with
* which to load pages.
* @context: The pooled_vio just acquired.
*
* Implements waiter_callback_fn.
*/
static void launch_cursor(struct vdo_waiter *waiter, void *context)
{
struct cursor *cursor = container_of(waiter, struct cursor, waiter);
struct pooled_vio *pooled = context;
cursor->vio = pooled;
pooled->vio.completion.parent = cursor;
pooled->vio.completion.callback_thread_id = cursor->parent->zone->thread_id;
traverse(cursor);
}
/**
* compute_boundary() - Compute the number of pages used at each level of the given root's tree.
*
* Return: The list of page counts as a boundary structure.
*/
static struct boundary compute_boundary(struct block_map *map, root_count_t root_index)
{
struct boundary boundary;
height_t height;
page_count_t leaf_pages = vdo_compute_block_map_page_count(map->entry_count);
/*
* Compute the leaf pages for this root. If the number of leaf pages does not distribute
* evenly, we must determine if this root gets an extra page. Extra pages are assigned to
* roots starting from tree 0.
*/
page_count_t last_tree_root = (leaf_pages - 1) % map->root_count;
page_count_t level_pages = leaf_pages / map->root_count;
if (root_index <= last_tree_root)
level_pages++;
for (height = 0; height < VDO_BLOCK_MAP_TREE_HEIGHT - 1; height++) {
boundary.levels[height] = level_pages;
level_pages = DIV_ROUND_UP(level_pages, VDO_BLOCK_MAP_ENTRIES_PER_PAGE);
}
/* The root node always exists, even if the root is otherwise unused. */
boundary.levels[VDO_BLOCK_MAP_TREE_HEIGHT - 1] = 1;
return boundary;
}
/**
* vdo_traverse_forest() - Walk the entire forest of a block map.
* @callback: A function to call with the pbn of each allocated node in the forest.
* @completion: The completion to notify on each traversed PBN, and when traversal completes.
*/
void vdo_traverse_forest(struct block_map *map, vdo_entry_callback_fn callback,
struct vdo_completion *completion)
{
root_count_t root;
struct cursors *cursors;
int result;
result = vdo_allocate_extended(struct cursors, map->root_count,
struct cursor, __func__, &cursors);
if (result != VDO_SUCCESS) {
vdo_fail_completion(completion, result);
return;
}
cursors->zone = &map->zones[0];
cursors->pool = cursors->zone->vio_pool;
cursors->entry_callback = callback;
cursors->completion = completion;
cursors->active_roots = map->root_count;
for (root = 0; root < map->root_count; root++) {
struct cursor *cursor = &cursors->cursors[root];
*cursor = (struct cursor) {
.tree = &map->forest->trees[root],
.height = VDO_BLOCK_MAP_TREE_HEIGHT - 1,
.parent = cursors,
.boundary = compute_boundary(map, root),
};
cursor->waiter.callback = launch_cursor;
acquire_vio_from_pool(cursors->pool, &cursor->waiter);
}
}
/**
* initialize_block_map_zone() - Initialize the per-zone portions of the block map.
* @maximum_age: The number of journal blocks before a dirtied page is considered old and must be
* written out.
*/
static int __must_check initialize_block_map_zone(struct block_map *map,
zone_count_t zone_number,
page_count_t cache_size,
block_count_t maximum_age)
{
int result;
block_count_t i;
struct vdo *vdo = map->vdo;
struct block_map_zone *zone = &map->zones[zone_number];
BUILD_BUG_ON(sizeof(struct page_descriptor) != sizeof(u64));
zone->zone_number = zone_number;
zone->thread_id = vdo->thread_config.logical_threads[zone_number];
zone->block_map = map;
result = vdo_allocate_extended(struct dirty_lists, maximum_age,
dirty_era_t, __func__,
&zone->dirty_lists);
if (result != VDO_SUCCESS)
return result;
zone->dirty_lists->maximum_age = maximum_age;
INIT_LIST_HEAD(&zone->dirty_lists->expired[VDO_TREE_PAGE]);
INIT_LIST_HEAD(&zone->dirty_lists->expired[VDO_CACHE_PAGE]);
for (i = 0; i < maximum_age; i++) {
INIT_LIST_HEAD(&zone->dirty_lists->eras[i][VDO_TREE_PAGE]);
INIT_LIST_HEAD(&zone->dirty_lists->eras[i][VDO_CACHE_PAGE]);
}
result = vdo_int_map_create(VDO_LOCK_MAP_CAPACITY, &zone->loading_pages);
if (result != VDO_SUCCESS)
return result;
result = make_vio_pool(vdo, BLOCK_MAP_VIO_POOL_SIZE,
zone->thread_id, VIO_TYPE_BLOCK_MAP_INTERIOR,
VIO_PRIORITY_METADATA, zone, &zone->vio_pool);
if (result != VDO_SUCCESS)
return result;
vdo_set_admin_state_code(&zone->state, VDO_ADMIN_STATE_NORMAL_OPERATION);
zone->page_cache.zone = zone;
zone->page_cache.vdo = vdo;
zone->page_cache.page_count = cache_size / map->zone_count;
zone->page_cache.stats.free_pages = zone->page_cache.page_count;
result = allocate_cache_components(&zone->page_cache);
if (result != VDO_SUCCESS)
return result;
/* initialize empty circular queues */
INIT_LIST_HEAD(&zone->page_cache.lru_list);
INIT_LIST_HEAD(&zone->page_cache.outgoing_list);
return VDO_SUCCESS;
}
/* Implements vdo_zone_thread_getter_fn */
static thread_id_t get_block_map_zone_thread_id(void *context, zone_count_t zone_number)
{
struct block_map *map = context;
return map->zones[zone_number].thread_id;
}
/* Implements vdo_action_preamble_fn */
static void prepare_for_era_advance(void *context, struct vdo_completion *parent)
{
struct block_map *map = context;
map->current_era_point = map->pending_era_point;
vdo_finish_completion(parent);
}
/* Implements vdo_zone_action_fn */
static void advance_block_map_zone_era(void *context, zone_count_t zone_number,
struct vdo_completion *parent)
{
struct block_map *map = context;
struct block_map_zone *zone = &map->zones[zone_number];
update_period(zone->dirty_lists, map->current_era_point);
write_expired_elements(zone);
vdo_finish_completion(parent);
}
/*
* Schedule an era advance if necessary. This method should not be called directly. Rather, call
* vdo_schedule_default_action() on the block map's action manager.
*
* Implements vdo_action_scheduler_fn.
*/
static bool schedule_era_advance(void *context)
{
struct block_map *map = context;
if (map->current_era_point == map->pending_era_point)
return false;
return vdo_schedule_action(map->action_manager, prepare_for_era_advance,
advance_block_map_zone_era, NULL, NULL);
}
static void uninitialize_block_map_zone(struct block_map_zone *zone)
{
struct vdo_page_cache *cache = &zone->page_cache;
vdo_free(vdo_forget(zone->dirty_lists));
free_vio_pool(vdo_forget(zone->vio_pool));
vdo_int_map_free(vdo_forget(zone->loading_pages));
if (cache->infos != NULL) {
struct page_info *info;
for (info = cache->infos; info < cache->infos + cache->page_count; info++)
free_vio(vdo_forget(info->vio));
}
vdo_int_map_free(vdo_forget(cache->page_map));
vdo_free(vdo_forget(cache->infos));
vdo_free(vdo_forget(cache->pages));
}
void vdo_free_block_map(struct block_map *map)
{
zone_count_t zone;
if (map == NULL)
return;
for (zone = 0; zone < map->zone_count; zone++)
uninitialize_block_map_zone(&map->zones[zone]);
vdo_abandon_block_map_growth(map);
if (map->forest != NULL)
deforest(vdo_forget(map->forest), 0);
vdo_free(vdo_forget(map->action_manager));
vdo_free(map);
}
/* @journal may be NULL. */
int vdo_decode_block_map(struct block_map_state_2_0 state, block_count_t logical_blocks,
struct vdo *vdo, struct recovery_journal *journal,
nonce_t nonce, page_count_t cache_size, block_count_t maximum_age,
struct block_map **map_ptr)
{
struct block_map *map;
int result;
zone_count_t zone = 0;
BUILD_BUG_ON(VDO_BLOCK_MAP_ENTRIES_PER_PAGE !=
((VDO_BLOCK_SIZE - sizeof(struct block_map_page)) /
sizeof(struct block_map_entry)));
result = VDO_ASSERT(cache_size > 0, "block map cache size is specified");
if (result != VDO_SUCCESS)
return result;
result = vdo_allocate_extended(struct block_map,
vdo->thread_config.logical_zone_count,
struct block_map_zone, __func__, &map);
if (result != VDO_SUCCESS)
return result;
map->vdo = vdo;
map->root_origin = state.root_origin;
map->root_count = state.root_count;
map->entry_count = logical_blocks;
map->journal = journal;
map->nonce = nonce;
result = make_forest(map, map->entry_count);
if (result != VDO_SUCCESS) {
vdo_free_block_map(map);
return result;
}
replace_forest(map);
map->zone_count = vdo->thread_config.logical_zone_count;
for (zone = 0; zone < map->zone_count; zone++) {
result = initialize_block_map_zone(map, zone, cache_size, maximum_age);
if (result != VDO_SUCCESS) {
vdo_free_block_map(map);
return result;
}
}
result = vdo_make_action_manager(map->zone_count, get_block_map_zone_thread_id,
vdo_get_recovery_journal_thread_id(journal),
map, schedule_era_advance, vdo,
&map->action_manager);
if (result != VDO_SUCCESS) {
vdo_free_block_map(map);
return result;
}
*map_ptr = map;
return VDO_SUCCESS;
}
struct block_map_state_2_0 vdo_record_block_map(const struct block_map *map)
{
return (struct block_map_state_2_0) {
.flat_page_origin = VDO_BLOCK_MAP_FLAT_PAGE_ORIGIN,
/* This is the flat page count, which has turned out to always be 0. */
.flat_page_count = 0,
.root_origin = map->root_origin,
.root_count = map->root_count,
};
}
/* The block map needs to know the journals' sequence number to initialize the eras. */
void vdo_initialize_block_map_from_journal(struct block_map *map,
struct recovery_journal *journal)
{
zone_count_t z = 0;
map->current_era_point = vdo_get_recovery_journal_current_sequence_number(journal);
map->pending_era_point = map->current_era_point;
for (z = 0; z < map->zone_count; z++) {
struct dirty_lists *dirty_lists = map->zones[z].dirty_lists;
VDO_ASSERT_LOG_ONLY(dirty_lists->next_period == 0, "current period not set");
dirty_lists->oldest_period = map->current_era_point;
dirty_lists->next_period = map->current_era_point + 1;
dirty_lists->offset = map->current_era_point % dirty_lists->maximum_age;
}
}
/* Compute the logical zone for the LBN of a data vio. */
zone_count_t vdo_compute_logical_zone(struct data_vio *data_vio)
{
struct block_map *map = vdo_from_data_vio(data_vio)->block_map;
struct tree_lock *tree_lock = &data_vio->tree_lock;
page_number_t page_number = data_vio->logical.lbn / VDO_BLOCK_MAP_ENTRIES_PER_PAGE;
tree_lock->tree_slots[0].page_index = page_number;
tree_lock->root_index = page_number % map->root_count;
return (tree_lock->root_index % map->zone_count);
}
void vdo_advance_block_map_era(struct block_map *map,
sequence_number_t recovery_block_number)
{
if (map == NULL)
return;
map->pending_era_point = recovery_block_number;
vdo_schedule_default_action(map->action_manager);
}
/* Implements vdo_admin_initiator_fn */
static void initiate_drain(struct admin_state *state)
{
struct block_map_zone *zone = container_of(state, struct block_map_zone, state);
VDO_ASSERT_LOG_ONLY((zone->active_lookups == 0),
"%s() called with no active lookups", __func__);
if (!vdo_is_state_suspending(state)) {
while (zone->dirty_lists->oldest_period < zone->dirty_lists->next_period)
expire_oldest_list(zone->dirty_lists);
write_expired_elements(zone);
}
check_for_drain_complete(zone);
}
/* Implements vdo_zone_action_fn. */
static void drain_zone(void *context, zone_count_t zone_number,
struct vdo_completion *parent)
{
struct block_map *map = context;
struct block_map_zone *zone = &map->zones[zone_number];
vdo_start_draining(&zone->state,
vdo_get_current_manager_operation(map->action_manager),
parent, initiate_drain);
}
void vdo_drain_block_map(struct block_map *map, const struct admin_state_code *operation,
struct vdo_completion *parent)
{
vdo_schedule_operation(map->action_manager, operation, NULL, drain_zone, NULL,
parent);
}
/* Implements vdo_zone_action_fn. */
static void resume_block_map_zone(void *context, zone_count_t zone_number,
struct vdo_completion *parent)
{
struct block_map *map = context;
struct block_map_zone *zone = &map->zones[zone_number];
vdo_fail_completion(parent, vdo_resume_if_quiescent(&zone->state));
}
void vdo_resume_block_map(struct block_map *map, struct vdo_completion *parent)
{
vdo_schedule_operation(map->action_manager, VDO_ADMIN_STATE_RESUMING,
NULL, resume_block_map_zone, NULL, parent);
}
/* Allocate an expanded collection of trees, for a future growth. */
int vdo_prepare_to_grow_block_map(struct block_map *map,
block_count_t new_logical_blocks)
{
if (map->next_entry_count == new_logical_blocks)
return VDO_SUCCESS;
if (map->next_entry_count > 0)
vdo_abandon_block_map_growth(map);
if (new_logical_blocks < map->entry_count) {
map->next_entry_count = map->entry_count;
return VDO_SUCCESS;
}
return make_forest(map, new_logical_blocks);
}
/* Implements vdo_action_preamble_fn */
static void grow_forest(void *context, struct vdo_completion *completion)
{
replace_forest(context);
vdo_finish_completion(completion);
}
/* Requires vdo_prepare_to_grow_block_map() to have been previously called. */
void vdo_grow_block_map(struct block_map *map, struct vdo_completion *parent)
{
vdo_schedule_operation(map->action_manager,
VDO_ADMIN_STATE_SUSPENDED_OPERATION,
grow_forest, NULL, NULL, parent);
}
void vdo_abandon_block_map_growth(struct block_map *map)
{
struct forest *forest = vdo_forget(map->next_forest);
if (forest != NULL)
deforest(forest, forest->segments - 1);
map->next_entry_count = 0;
}
/* Release the page completion and then continue the requester. */
static inline void finish_processing_page(struct vdo_completion *completion, int result)
{
struct vdo_completion *parent = completion->parent;
vdo_release_page_completion(completion);
vdo_continue_completion(parent, result);
}
static void handle_page_error(struct vdo_completion *completion)
{
finish_processing_page(completion, completion->result);
}
/* Fetch the mapping page for a block map update, and call the provided handler when fetched. */
static void fetch_mapping_page(struct data_vio *data_vio, bool modifiable,
vdo_action_fn action)
{
struct block_map_zone *zone = data_vio->logical.zone->block_map_zone;
if (vdo_is_state_draining(&zone->state)) {
continue_data_vio_with_error(data_vio, VDO_SHUTTING_DOWN);
return;
}
vdo_get_page(&data_vio->page_completion, zone,
data_vio->tree_lock.tree_slots[0].block_map_slot.pbn,
modifiable, &data_vio->vio.completion,
action, handle_page_error, false);
}
/**
* clear_mapped_location() - Clear a data_vio's mapped block location, setting it to be unmapped.
*
* This indicates the block map entry for the logical block is either unmapped or corrupted.
*/
static void clear_mapped_location(struct data_vio *data_vio)
{
data_vio->mapped = (struct zoned_pbn) {
.state = VDO_MAPPING_STATE_UNMAPPED,
};
}
/**
* set_mapped_location() - Decode and validate a block map entry, and set the mapped location of a
* data_vio.
*
* Return: VDO_SUCCESS or VDO_BAD_MAPPING if the map entry is invalid or an error code for any
* other failure
*/
static int __must_check set_mapped_location(struct data_vio *data_vio,
const struct block_map_entry *entry)
{
/* Unpack the PBN for logging purposes even if the entry is invalid. */
struct data_location mapped = vdo_unpack_block_map_entry(entry);
if (vdo_is_valid_location(&mapped)) {
int result;
result = vdo_get_physical_zone(vdo_from_data_vio(data_vio),
mapped.pbn, &data_vio->mapped.zone);
if (result == VDO_SUCCESS) {
data_vio->mapped.pbn = mapped.pbn;
data_vio->mapped.state = mapped.state;
return VDO_SUCCESS;
}
/*
* Return all errors not specifically known to be errors from validating the
* location.
*/
if ((result != VDO_OUT_OF_RANGE) && (result != VDO_BAD_MAPPING))
return result;
}
/*
* Log the corruption even if we wind up ignoring it for write VIOs, converting all cases
* to VDO_BAD_MAPPING.
*/
vdo_log_error_strerror(VDO_BAD_MAPPING,
"PBN %llu with state %u read from the block map was invalid",
(unsigned long long) mapped.pbn, mapped.state);
/*
* A read VIO has no option but to report the bad mapping--reading zeros would be hiding
* known data loss.
*/
if (!data_vio->write)
return VDO_BAD_MAPPING;
/*
* A write VIO only reads this mapping to decref the old block. Treat this as an unmapped
* entry rather than fail the write.
*/
clear_mapped_location(data_vio);
return VDO_SUCCESS;
}
/* This callback is registered in vdo_get_mapped_block(). */
static void get_mapping_from_fetched_page(struct vdo_completion *completion)
{
int result;
struct vdo_page_completion *vpc = as_vdo_page_completion(completion);
const struct block_map_page *page;
const struct block_map_entry *entry;
struct data_vio *data_vio = as_data_vio(completion->parent);
struct block_map_tree_slot *tree_slot;
if (completion->result != VDO_SUCCESS) {
finish_processing_page(completion, completion->result);
return;
}
result = validate_completed_page(vpc, false);
if (result != VDO_SUCCESS) {
finish_processing_page(completion, result);
return;
}
page = (const struct block_map_page *) get_page_buffer(vpc->info);
tree_slot = &data_vio->tree_lock.tree_slots[0];
entry = &page->entries[tree_slot->block_map_slot.slot];
result = set_mapped_location(data_vio, entry);
finish_processing_page(completion, result);
}
void vdo_update_block_map_page(struct block_map_page *page, struct data_vio *data_vio,
physical_block_number_t pbn,
enum block_mapping_state mapping_state,
sequence_number_t *recovery_lock)
{
struct block_map_zone *zone = data_vio->logical.zone->block_map_zone;
struct block_map *block_map = zone->block_map;
struct recovery_journal *journal = block_map->journal;
sequence_number_t old_locked, new_locked;
struct tree_lock *tree_lock = &data_vio->tree_lock;
/* Encode the new mapping. */
page->entries[tree_lock->tree_slots[tree_lock->height].block_map_slot.slot] =
vdo_pack_block_map_entry(pbn, mapping_state);
/* Adjust references on the recovery journal blocks. */
old_locked = *recovery_lock;
new_locked = data_vio->recovery_sequence_number;
if ((old_locked == 0) || (old_locked > new_locked)) {
vdo_acquire_recovery_journal_block_reference(journal, new_locked,
VDO_ZONE_TYPE_LOGICAL,
zone->zone_number);
if (old_locked > 0) {
vdo_release_recovery_journal_block_reference(journal, old_locked,
VDO_ZONE_TYPE_LOGICAL,
zone->zone_number);
}
*recovery_lock = new_locked;
}
/*
* FIXME: explain this more
* Release the transferred lock from the data_vio.
*/
vdo_release_journal_entry_lock(journal, new_locked);
data_vio->recovery_sequence_number = 0;
}
static void put_mapping_in_fetched_page(struct vdo_completion *completion)
{
struct data_vio *data_vio = as_data_vio(completion->parent);
sequence_number_t old_lock;
struct vdo_page_completion *vpc;
struct page_info *info;
int result;
if (completion->result != VDO_SUCCESS) {
finish_processing_page(completion, completion->result);
return;
}
vpc = as_vdo_page_completion(completion);
result = validate_completed_page(vpc, true);
if (result != VDO_SUCCESS) {
finish_processing_page(completion, result);
return;
}
info = vpc->info;
old_lock = info->recovery_lock;
vdo_update_block_map_page((struct block_map_page *) get_page_buffer(info),
data_vio, data_vio->new_mapped.pbn,
data_vio->new_mapped.state, &info->recovery_lock);
set_info_state(info, PS_DIRTY);
add_to_dirty_lists(info->cache->zone, &info->state_entry,
VDO_CACHE_PAGE, old_lock, info->recovery_lock);
finish_processing_page(completion, VDO_SUCCESS);
}
/* Read a stored block mapping into a data_vio. */
void vdo_get_mapped_block(struct data_vio *data_vio)
{
if (data_vio->tree_lock.tree_slots[0].block_map_slot.pbn == VDO_ZERO_BLOCK) {
/*
* We know that the block map page for this LBN has not been allocated, so the
* block must be unmapped.
*/
clear_mapped_location(data_vio);
continue_data_vio(data_vio);
return;
}
fetch_mapping_page(data_vio, false, get_mapping_from_fetched_page);
}
/* Update a stored block mapping to reflect a data_vio's new mapping. */
void vdo_put_mapped_block(struct data_vio *data_vio)
{
fetch_mapping_page(data_vio, true, put_mapping_in_fetched_page);
}
struct block_map_statistics vdo_get_block_map_statistics(struct block_map *map)
{
zone_count_t zone = 0;
struct block_map_statistics totals;
memset(&totals, 0, sizeof(struct block_map_statistics));
for (zone = 0; zone < map->zone_count; zone++) {
const struct block_map_statistics *stats =
&(map->zones[zone].page_cache.stats);
totals.dirty_pages += READ_ONCE(stats->dirty_pages);
totals.clean_pages += READ_ONCE(stats->clean_pages);
totals.free_pages += READ_ONCE(stats->free_pages);
totals.failed_pages += READ_ONCE(stats->failed_pages);
totals.incoming_pages += READ_ONCE(stats->incoming_pages);
totals.outgoing_pages += READ_ONCE(stats->outgoing_pages);
totals.cache_pressure += READ_ONCE(stats->cache_pressure);
totals.read_count += READ_ONCE(stats->read_count);
totals.write_count += READ_ONCE(stats->write_count);
totals.failed_reads += READ_ONCE(stats->failed_reads);
totals.failed_writes += READ_ONCE(stats->failed_writes);
totals.reclaimed += READ_ONCE(stats->reclaimed);
totals.read_outgoing += READ_ONCE(stats->read_outgoing);
totals.found_in_cache += READ_ONCE(stats->found_in_cache);
totals.discard_required += READ_ONCE(stats->discard_required);
totals.wait_for_page += READ_ONCE(stats->wait_for_page);
totals.fetch_required += READ_ONCE(stats->fetch_required);
totals.pages_loaded += READ_ONCE(stats->pages_loaded);
totals.pages_saved += READ_ONCE(stats->pages_saved);
totals.flush_count += READ_ONCE(stats->flush_count);
}
return totals;
}
Codebase Browser
linux