diff options
Diffstat (limited to 'drivers/md/dm-vdo/indexer/index-page-map.c')
| -rw-r--r-- | drivers/md/dm-vdo/indexer/index-page-map.c | 173 |
1 files changed, 173 insertions, 0 deletions
diff --git a/drivers/md/dm-vdo/indexer/index-page-map.c b/drivers/md/dm-vdo/indexer/index-page-map.c new file mode 100644 index 0000000000..00b44e07d0 --- /dev/null +++ b/drivers/md/dm-vdo/indexer/index-page-map.c @@ -0,0 +1,173 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2023 Red Hat + */ + +#include "index-page-map.h" + +#include "errors.h" +#include "logger.h" +#include "memory-alloc.h" +#include "numeric.h" +#include "permassert.h" +#include "string-utils.h" +#include "thread-utils.h" + +#include "hash-utils.h" +#include "indexer.h" + +/* + * The index page map is conceptually a two-dimensional array indexed by chapter number and index + * page number within the chapter. Each entry contains the number of the last delta list on that + * index page. In order to save memory, the information for the last page in each chapter is not + * recorded, as it is known from the geometry. + */ + +static const u8 PAGE_MAP_MAGIC[] = "ALBIPM02"; + +#define PAGE_MAP_MAGIC_LENGTH (sizeof(PAGE_MAP_MAGIC) - 1) + +static inline u32 get_entry_count(const struct index_geometry *geometry) +{ + return geometry->chapters_per_volume * (geometry->index_pages_per_chapter - 1); +} + +int uds_make_index_page_map(const struct index_geometry *geometry, + struct index_page_map **map_ptr) +{ + int result; + struct index_page_map *map; + + result = vdo_allocate(1, struct index_page_map, "page map", &map); + if (result != VDO_SUCCESS) + return result; + + map->geometry = geometry; + map->entries_per_chapter = geometry->index_pages_per_chapter - 1; + result = vdo_allocate(get_entry_count(geometry), u16, "Index Page Map Entries", + &map->entries); + if (result != VDO_SUCCESS) { + uds_free_index_page_map(map); + return result; + } + + *map_ptr = map; + return UDS_SUCCESS; +} + +void uds_free_index_page_map(struct index_page_map *map) +{ + if (map != NULL) { + vdo_free(map->entries); + vdo_free(map); + } +} + +void uds_update_index_page_map(struct index_page_map *map, u64 virtual_chapter_number, + u32 chapter_number, u32 index_page_number, + u32 delta_list_number) +{ + size_t slot; + + map->last_update = virtual_chapter_number; + if (index_page_number == map->entries_per_chapter) + return; + + slot = (chapter_number * map->entries_per_chapter) + index_page_number; + map->entries[slot] = delta_list_number; +} + +u32 uds_find_index_page_number(const struct index_page_map *map, + const struct uds_record_name *name, u32 chapter_number) +{ + u32 delta_list_number = uds_hash_to_chapter_delta_list(name, map->geometry); + u32 slot = chapter_number * map->entries_per_chapter; + u32 page; + + for (page = 0; page < map->entries_per_chapter; page++) { + if (delta_list_number <= map->entries[slot + page]) + break; + } + + return page; +} + +void uds_get_list_number_bounds(const struct index_page_map *map, u32 chapter_number, + u32 index_page_number, u32 *lowest_list, + u32 *highest_list) +{ + u32 slot = chapter_number * map->entries_per_chapter; + + *lowest_list = ((index_page_number == 0) ? + 0 : map->entries[slot + index_page_number - 1] + 1); + *highest_list = ((index_page_number < map->entries_per_chapter) ? + map->entries[slot + index_page_number] : + map->geometry->delta_lists_per_chapter - 1); +} + +u64 uds_compute_index_page_map_save_size(const struct index_geometry *geometry) +{ + return PAGE_MAP_MAGIC_LENGTH + sizeof(u64) + sizeof(u16) * get_entry_count(geometry); +} + +int uds_write_index_page_map(struct index_page_map *map, struct buffered_writer *writer) +{ + int result; + u8 *buffer; + size_t offset = 0; + u64 saved_size = uds_compute_index_page_map_save_size(map->geometry); + u32 i; + + result = vdo_allocate(saved_size, u8, "page map data", &buffer); + if (result != VDO_SUCCESS) + return result; + + memcpy(buffer, PAGE_MAP_MAGIC, PAGE_MAP_MAGIC_LENGTH); + offset += PAGE_MAP_MAGIC_LENGTH; + encode_u64_le(buffer, &offset, map->last_update); + for (i = 0; i < get_entry_count(map->geometry); i++) + encode_u16_le(buffer, &offset, map->entries[i]); + + result = uds_write_to_buffered_writer(writer, buffer, offset); + vdo_free(buffer); + if (result != UDS_SUCCESS) + return result; + + return uds_flush_buffered_writer(writer); +} + +int uds_read_index_page_map(struct index_page_map *map, struct buffered_reader *reader) +{ + int result; + u8 magic[PAGE_MAP_MAGIC_LENGTH]; + u8 *buffer; + size_t offset = 0; + u64 saved_size = uds_compute_index_page_map_save_size(map->geometry); + u32 i; + + result = vdo_allocate(saved_size, u8, "page map data", &buffer); + if (result != VDO_SUCCESS) + return result; + + result = uds_read_from_buffered_reader(reader, buffer, saved_size); + if (result != UDS_SUCCESS) { + vdo_free(buffer); + return result; + } + + memcpy(&magic, buffer, PAGE_MAP_MAGIC_LENGTH); + offset += PAGE_MAP_MAGIC_LENGTH; + if (memcmp(magic, PAGE_MAP_MAGIC, PAGE_MAP_MAGIC_LENGTH) != 0) { + vdo_free(buffer); + return UDS_CORRUPT_DATA; + } + + decode_u64_le(buffer, &offset, &map->last_update); + for (i = 0; i < get_entry_count(map->geometry); i++) + decode_u16_le(buffer, &offset, &map->entries[i]); + + vdo_free(buffer); + vdo_log_debug("read index page map, last update %llu", + (unsigned long long) map->last_update); + return UDS_SUCCESS; +} |