153 lines
3.6 KiB
C++
153 lines
3.6 KiB
C++
#pragma once
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#include "crc32c.h"
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#define MIN_JOURNAL_SIZE 4*1024*1024
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#define JOURNAL_MAGIC 0x4A33
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#define JOURNAL_BUFFER_SIZE 4*1024*1024
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// Journal entries
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// Journal entries are linked to each other by their crc32 value
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// The journal is almost a blockchain, because object versions constantly increase
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#define JE_START 0x01
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#define JE_SMALL_WRITE 0x02
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#define JE_BIG_WRITE 0x03
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#define JE_STABLE 0x04
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#define JE_DELETE 0x05
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// crc32c comes first to ease calculation and is equal to crc32()
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struct __attribute__((__packed__)) journal_entry_start
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{
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uint32_t crc32;
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uint16_t magic;
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uint16_t type;
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uint32_t size;
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uint32_t reserved;
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uint64_t journal_start;
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};
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struct __attribute__((__packed__)) journal_entry_small_write
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{
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uint32_t crc32;
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uint16_t magic;
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uint16_t type;
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uint32_t size;
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uint32_t crc32_prev;
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object_id oid;
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uint64_t version;
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uint32_t offset;
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uint32_t len;
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// small_write entries contain <len> bytes of data which is stored in next sectors
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// data_offset is its offset within journal
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uint64_t data_offset;
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uint32_t crc32_data;
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};
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struct __attribute__((__packed__)) journal_entry_big_write
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{
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uint32_t crc32;
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uint16_t magic;
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uint16_t type;
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uint32_t size;
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uint32_t crc32_prev;
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object_id oid;
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uint64_t version;
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uint64_t location;
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};
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struct __attribute__((__packed__)) journal_entry_stable
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{
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uint32_t crc32;
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uint16_t magic;
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uint16_t type;
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uint32_t size;
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uint32_t crc32_prev;
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object_id oid;
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uint64_t version;
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};
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struct __attribute__((__packed__)) journal_entry_del
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{
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uint32_t crc32;
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uint16_t magic;
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uint16_t type;
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uint32_t size;
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uint32_t crc32_prev;
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object_id oid;
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uint64_t version;
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};
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struct __attribute__((__packed__)) journal_entry
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{
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union
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{
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struct __attribute__((__packed__))
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{
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uint32_t crc32;
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uint16_t magic;
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uint16_t type;
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uint32_t size;
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uint32_t crc32_prev;
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};
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journal_entry_start start;
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journal_entry_small_write small_write;
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journal_entry_big_write big_write;
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journal_entry_stable stable;
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journal_entry_del del;
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};
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};
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inline uint32_t je_crc32(journal_entry *je)
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{
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// 0x48674bc7 = crc32(4 zero bytes)
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return crc32c(0x48674bc7, ((uint8_t*)je)+4, je->size-4);
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}
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struct journal_sector_info_t
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{
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uint64_t offset;
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uint64_t usage_count;
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};
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struct journal_t
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{
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int fd;
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uint64_t device_size;
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bool inmemory = false;
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void *buffer = NULL;
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uint64_t offset, len;
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uint64_t next_free = 512;
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uint64_t used_start = 512;
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uint32_t crc32_last = 0;
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// Current sector(s) used for writing
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void *sector_buf = NULL;
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journal_sector_info_t *sector_info = NULL;
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uint64_t sector_count;
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int cur_sector = 0;
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int in_sector_pos = 512; // no free space because sector is initially unmapped
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// Used sector map
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// May use ~ 80 MB per 1 GB of used journal space in the worst case
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std::map<uint64_t, uint64_t> used_sectors;
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~journal_t();
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bool trim();
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};
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struct blockstore_journal_check_t
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{
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blockstore *bs;
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uint64_t next_pos, next_sector, next_in_pos;
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int sectors_required;
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bool right_dir; // writing to the end or the beginning of the ring buffer
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blockstore_journal_check_t(blockstore *bs);
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int check_available(blockstore_operation *op, int required, int size, int data_after);
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};
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journal_entry* prefill_single_journal_entry(journal_t & journal, uint16_t type, uint32_t size);
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void prepare_journal_sector_write(journal_t & journal, io_uring_sqe *sqe, std::function<void(ring_data_t*)> cb);
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