143 lines
5.3 KiB
C++
143 lines
5.3 KiB
C++
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#include "blockstore.h"
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int blockstore::fulfill_read(blockstore_operation & read_op, uint32_t item_start, uint32_t item_end,
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uint32_t item_state, uint64_t item_version, uint64_t item_location)
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{
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uint32_t cur_start = item_start;
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if (cur_start < read_op.offset + read_op.len && item_end > read_op.offset)
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{
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cur_start = cur_start < read_op.offset ? read_op.offset : cur_start;
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item_end = item_end > read_op.offset + read_op.len ? read_op.offset + read_op.len : item_end;
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auto fulfill_near = read_op.read_vec.lower_bound(cur_start);
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if (fulfill_near != read_op.read_vec.begin())
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{
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fulfill_near--;
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if (fulfill_near->first + fulfill_near->second.iov_len <= cur_start)
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{
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fulfill_near++;
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}
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}
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while (fulfill_near != read_op.read_vec.end() && fulfill_near->first < item_end)
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{
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if (fulfill_near->first > cur_start)
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{
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if (item_state == ST_IN_FLIGHT)
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{
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// Pause until it's written somewhere
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read_op.wait_for = WAIT_IN_FLIGHT;
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read_op.wait_version = item_version;
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return -1;
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}
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struct io_uring_sqe *sqe = io_uring_get_sqe(ring);
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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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read_op.wait_for = WAIT_SQE;
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return -1;
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}
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read_op.read_vec[cur_start] = (struct iovec){
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read_op.buf + cur_start - read_op.offset,
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fulfill_near->first - cur_start
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};
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io_uring_prep_readv(
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sqe,
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IS_JOURNAL(item_state) ? journal_fd : data_fd,
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// FIXME: &read_op.read_vec is forbidden
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&read_op.read_vec[cur_start], 1,
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(IS_JOURNAL(item_state) ? journal_offset : data_offset) + item_location + cur_start - item_start
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);
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io_uring_sqe_set_data(sqe, 0/*read op link*/);
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}
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cur_start = fulfill_near->first + fulfill_near->second.iov_len;
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fulfill_near++;
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}
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if (cur_start < item_end)
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{
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if (item_state == ST_IN_FLIGHT)
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{
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// Pause until it's written somewhere
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read_op.wait_for = WAIT_IN_FLIGHT;
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read_op.wait_version = item_version;
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return -1;
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}
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struct io_uring_sqe *sqe = io_uring_get_sqe(ring);
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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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read_op.wait_for = WAIT_SQE;
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return -1;
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}
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read_op.read_vec[cur_start] = (struct iovec){
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read_op.buf + cur_start - read_op.offset,
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item_end - cur_start
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};
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io_uring_prep_readv(
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sqe,
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IS_JOURNAL(item_state) ? journal_fd : data_fd,
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&read_op.read_vec[cur_start], 1,
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(IS_JOURNAL(item_state) ? journal_offset : data_offset) + item_location + cur_start - item_start
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);
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io_uring_sqe_set_data(sqe, 0/*read op link*/);
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}
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}
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return 0;
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}
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int blockstore::read(blockstore_operation *read_op)
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{
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auto clean_it = object_db.find(read_op->oid);
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auto dirty_it = dirty_queue.find(read_op->oid);
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if (clean_it == object_db.end() && dirty_it == object_db.end())
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{
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// region is not allocated - return zeroes
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memset(read_op->buf, 0, read_op->len);
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read_op->callback(read_op);
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return 0;
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}
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unsigned prev_sqe_pos = ring->sq.sqe_tail;
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uint64_t fulfilled = 0;
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if (dirty_it != object_db.end())
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{
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dirty_list dirty = dirty_it->second;
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for (int i = dirty.size()-1; i >= 0; i--)
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{
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if (read_op->flags == OP_READ_DIRTY || IS_STABLE(dirty[i].state))
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{
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if (fulfill_read(*read_op, dirty[i].offset, dirty[i].offset + dirty[i].size, dirty[i].state, dirty[i].version, dirty[i].location) < 0)
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{
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// need to wait for something, undo added requests and requeue op
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ring->sq.sqe_tail = prev_sqe_pos;
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read_op->read_vec.clear();
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submit_queue.push_front(read_op);
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return 0;
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}
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}
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}
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}
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if (clean_it != object_db.end())
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{
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if (fulfill_read(*read_op, 0, block_size, ST_CURRENT, 0, clean_it->second.location) < 0)
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{
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// need to wait for something, undo added requests and requeue op
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ring->sq.sqe_tail = prev_sqe_pos;
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read_op->read_vec.clear();
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submit_queue.push_front(read_op);
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return 0;
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}
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}
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if (!read_op->read_vec.size())
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{
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// region is not allocated - return zeroes
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free(read_op);
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memset(read_op->buf, 0, read_op->len);
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read_op->callback(read_op);
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return 0;
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}
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int ret = io_uring_submit(ring);
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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 0;
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}
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