forked from vitalif/vitastor
145 lines
5.7 KiB
C++
145 lines
5.7 KiB
C++
#include "blockstore.h"
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// First step of the write algorithm: dequeue operation and submit initial write(s)
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int blockstore::dequeue_write(blockstore_operation *op)
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{
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auto dirty_it = dirty_db.find((obj_ver_id){
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.oid = op->oid,
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.version = op->version,
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});
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if (op->len == block_size)
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{
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// Big (redirect) write
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uint64_t loc = allocator_find_free(data_alloc);
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if (loc == (uint64_t)-1)
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{
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// no space
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op->retval = -ENOSPC;
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op->callback(op);
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return 1;
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}
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struct io_uring_sqe *sqe = get_sqe();
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if (!sqe)
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{
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// Pause until there are more requests available
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op->wait_for = WAIT_SQE;
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op->wait_detail = 1;
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return 0;
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}
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struct ring_data_t *data = ((ring_data_t*)sqe->user_data);
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dirty_it->second.location = loc << block_order;
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dirty_it->second.state = ST_D_SUBMITTED;
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allocator_set(data_alloc, loc, true);
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data->iov = (struct iovec){ op->buf, op->len };
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data->op = op;
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io_uring_prep_writev(
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sqe, data_fd, &data->iov, 1, data_offset + (loc << block_order)
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);
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op->pending_ops = 1;
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op->used_journal_sector = 0;
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}
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else
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{
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// Small (journaled) write
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// First check if the journal has sufficient space
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// FIXME Always two SQEs for now. Although it's possible to send 1 sometimes
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bool two_sqes = true;
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uint64_t next_pos = journal.next_free;
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if (512 - journal.in_sector_pos < sizeof(struct journal_entry_small_write))
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{
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next_pos = next_pos + 512;
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//if (journal.len - next_pos < op->len)
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// two_sqes = true;
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if (next_pos >= journal.len)
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next_pos = 512;
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// Also check if we have an unused memory buffer for the journal sector
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if (journal.sector_info[((journal.cur_sector + 1) % journal.sector_count)].usage_count > 0)
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{
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// No memory buffer available. Wait for it.
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op->wait_for = WAIT_JOURNAL_BUFFER;
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return 0;
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}
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}
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//else if (journal.sector_info[journal.cur_sector].offset + 512 != journal.next_free ||
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// journal.len - next_pos < op->len)
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// two_sqes = true;
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next_pos = (journal.len - next_pos < op->len ? 512 : next_pos) + op->len;
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if (next_pos >= journal.used_start)
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{
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// No space in the journal. Wait for it.
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op->wait_for = WAIT_JOURNAL;
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op->wait_detail = next_pos;
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return 0;
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}
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// There is sufficient space. Get SQE(s)
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unsigned prev_sqe_pos = ringloop->ring->sq.sqe_tail;
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struct io_uring_sqe *sqe1 = get_sqe(), *sqe2 = two_sqes ? get_sqe() : NULL;
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if (!sqe1 || two_sqes && !sqe2)
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{
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// Pause until there are more requests available
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op->wait_for = WAIT_SQE;
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op->wait_detail = two_sqes ? 2 : 1;
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ringloop->ring->sq.sqe_tail = prev_sqe_pos;
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return 0;
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}
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struct ring_data_t *data1 = ((ring_data_t*)sqe1->user_data);
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struct ring_data_t *data2 = two_sqes ? ((ring_data_t*)sqe2->user_data) : NULL;
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// Got SQEs. Prepare journal sector write
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if (512 - journal.in_sector_pos < sizeof(struct journal_entry_small_write))
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{
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// Move to the next journal sector
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// Also select next sector buffer in memory
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journal.cur_sector = ((journal.cur_sector + 1) % journal.sector_count);
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journal.sector_info[journal.cur_sector].offset = journal.next_free;
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journal.in_sector_pos = 0;
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journal.next_free = (journal.next_free + 512) >= journal.len ? journal.next_free + 512 : 512;
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memset(journal.sector_buf + 512*journal.cur_sector, 0, 512);
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}
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journal_entry_small_write *je = (struct journal_entry_small_write*)(
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journal.sector_buf + 512*journal.cur_sector + journal.in_sector_pos
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);
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*je = {
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.crc32 = 0,
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.magic = JOURNAL_MAGIC,
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.type = JE_SMALL_WRITE,
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.size = sizeof(struct journal_entry_small_write),
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.crc32_prev = journal.crc32_last,
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.oid = op->oid,
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.version = op->version,
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.offset = op->offset,
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.len = op->len,
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};
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je->crc32 = je_crc32((journal_entry*)je);
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data1->iov = (struct iovec){ journal.sector_buf + 512*journal.cur_sector, 512 };
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data1->op = op;
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io_uring_prep_writev(
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sqe1, journal.fd, &data1->iov, 1, journal.offset + journal.sector_info[journal.cur_sector].offset
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);
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// Prepare journal data write
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if (journal.len - journal.next_free < op->len)
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journal.next_free = 512;
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data2->iov = (struct iovec){ op->buf, op->len };
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data2->op = op;
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io_uring_prep_writev(
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sqe2, journal.fd, &data2->iov, 1, journal.offset + journal.next_free
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);
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dirty_it->second.location = journal.next_free;
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dirty_it->second.state = ST_J_SUBMITTED;
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// Move journal.next_free and save last write for current sector
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journal.next_free += op->len;
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if (journal.next_free >= journal.len)
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journal.next_free = 512;
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journal.sector_info[journal.cur_sector].usage_count++;
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journal.crc32_last = je->crc32;
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op->pending_ops = 2;
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op->used_journal_sector = 1 + journal.cur_sector;
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}
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in_process_ops.insert(op);
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int ret = ringloop->submit();
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if (ret < 0)
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{
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throw new std::runtime_error(std::string("io_uring_submit: ") + strerror(-ret));
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}
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return 1;
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}
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