Simplified distributed block storage with strong consistency, like in Ceph
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

256 lines
8.9 KiB

// Copyright (c) Vitaliy Filippov, 2019+
// License: VNPL-1.0 (see README.md for details)
#include "blockstore_impl.h"
int blockstore_impl_t::fulfill_read_push(blockstore_op_t *op, void *buf, uint64_t offset, uint64_t len,
uint32_t item_state, uint64_t item_version)
{
if (!len)
{
// Zero-length version - skip
return 1;
}
else if (IS_IN_FLIGHT(item_state))
{
// Write not finished yet - skip
return 1;
}
else if (IS_DELETE(item_state))
{
// item is unallocated - return zeroes
memset(buf, 0, len);
return 1;
}
if (journal.inmemory && IS_JOURNAL(item_state))
{
memcpy(buf, journal.buffer + offset, len);
return 1;
}
BS_SUBMIT_GET_SQE(sqe, data);
data->iov = (struct iovec){ buf, len };
PRIV(op)->pending_ops++;
my_uring_prep_readv(
sqe,
IS_JOURNAL(item_state) ? journal.fd : data_fd,
&data->iov, 1,
(IS_JOURNAL(item_state) ? journal.offset : data_offset) + offset
);
data->callback = [this, op](ring_data_t *data) { handle_read_event(data, op); };
return 1;
}
// FIXME I've seen a bug here so I want some tests
int blockstore_impl_t::fulfill_read(blockstore_op_t *read_op, uint64_t &fulfilled, uint32_t item_start, uint32_t item_end,
uint32_t item_state, uint64_t item_version, uint64_t item_location)
{
uint32_t cur_start = item_start;
if (cur_start < read_op->offset + read_op->len && item_end > read_op->offset)
{
cur_start = cur_start < read_op->offset ? read_op->offset : cur_start;
item_end = item_end > read_op->offset + read_op->len ? read_op->offset + read_op->len : item_end;
auto it = PRIV(read_op)->read_vec.begin();
while (1)
{
for (; it != PRIV(read_op)->read_vec.end(); it++)
{
if (it->offset >= cur_start)
{
break;
}
else if (it->offset + it->len > cur_start)
{
cur_start = it->offset + it->len;
if (cur_start >= item_end)
{
goto endwhile;
}
}
}
if (it == PRIV(read_op)->read_vec.end() || it->offset > cur_start)
{
fulfill_read_t el = {
.offset = cur_start,
.len = it == PRIV(read_op)->read_vec.end() || it->offset >= item_end ? item_end-cur_start : it->offset-cur_start,
};
it = PRIV(read_op)->read_vec.insert(it, el);
if (!fulfill_read_push(read_op,
read_op->buf + el.offset - read_op->offset,
item_location + el.offset - item_start,
el.len, item_state, item_version))
{
return 0;
}
fulfilled += el.len;
}
cur_start = it->offset + it->len;
if (it == PRIV(read_op)->read_vec.end() || cur_start >= item_end)
{
break;
}
}
}
endwhile:
return 1;
}
int blockstore_impl_t::dequeue_read(blockstore_op_t *read_op)
{
auto clean_it = clean_db.find(read_op->oid);
auto dirty_it = dirty_db.upper_bound((obj_ver_id){
.oid = read_op->oid,
.version = UINT64_MAX,
});
if (dirty_it != dirty_db.begin())
dirty_it--;
bool clean_found = clean_it != clean_db.end();
bool dirty_found = (dirty_it != dirty_db.end() && dirty_it->first.oid == read_op->oid);
if (!clean_found && !dirty_found)
{
// region is not allocated - return zeroes
memset(read_op->buf, 0, read_op->len);
read_op->version = 0;
read_op->retval = read_op->len;
FINISH_OP(read_op);
return 1;
}
uint64_t fulfilled = 0;
PRIV(read_op)->pending_ops = 0;
uint64_t result_version = 0;
if (dirty_found)
{
while (dirty_it->first.oid == read_op->oid)
{
dirty_entry& dirty = dirty_it->second;
bool version_ok = read_op->version >= dirty_it->first.version;
if (IS_SYNCED(dirty.state))
{
if (!version_ok && read_op->version != 0)
read_op->version = dirty_it->first.version;
version_ok = true;
}
if (version_ok)
{
if (!result_version)
{
result_version = dirty_it->first.version;
}
if (!fulfill_read(read_op, fulfilled, dirty.offset, dirty.offset + dirty.len,
dirty.state, dirty_it->first.version, dirty.location + (IS_JOURNAL(dirty.state) ? 0 : dirty.offset)))
{
// need to wait. undo added requests, don't dequeue op
PRIV(read_op)->read_vec.clear();
return 0;
}
}
if (fulfilled == read_op->len || dirty_it == dirty_db.begin())
{
break;
}
dirty_it--;
}
}
if (clean_it != clean_db.end())
{
if (!result_version)
{
result_version = clean_it->second.version;
}
if (fulfilled < read_op->len)
{
if (!clean_entry_bitmap_size)
{
if (!fulfill_read(read_op, fulfilled, 0, block_size, (BS_ST_BIG_WRITE | BS_ST_STABLE), 0, clean_it->second.location))
{
// need to wait. undo added requests, don't dequeue op
PRIV(read_op)->read_vec.clear();
return 0;
}
}
else
{
uint64_t meta_loc = clean_it->second.location >> block_order;
uint8_t *clean_entry_bitmap;
if (inmemory_meta)
{
uint64_t sector = (meta_loc / (meta_block_size / clean_entry_size)) * meta_block_size;
uint64_t pos = (meta_loc % (meta_block_size / clean_entry_size));
clean_entry_bitmap = (uint8_t*)(metadata_buffer + sector + pos*clean_entry_size + sizeof(clean_disk_entry));
}
else
{
clean_entry_bitmap = (uint8_t*)(clean_bitmap + meta_loc*clean_entry_bitmap_size);
}
uint64_t bmp_start = 0, bmp_end = 0, bmp_size = block_size/bitmap_granularity;
while (bmp_start < bmp_size)
{
while (!(clean_entry_bitmap[bmp_end >> 3] & (1 << (bmp_end & 0x7))) && bmp_end < bmp_size)
{
bmp_end++;
}
if (bmp_end > bmp_start)
{
// fill with zeroes
fulfill_read(read_op, fulfilled, bmp_start * bitmap_granularity,
bmp_end * bitmap_granularity, (BS_ST_DELETE | BS_ST_STABLE), 0, 0);
}
bmp_start = bmp_end;
while (clean_entry_bitmap[bmp_end >> 3] & (1 << (bmp_end & 0x7)) && bmp_end < bmp_size)
{
bmp_end++;
}
if (bmp_end > bmp_start)
{
if (!fulfill_read(read_op, fulfilled, bmp_start * bitmap_granularity,
bmp_end * bitmap_granularity, (BS_ST_BIG_WRITE | BS_ST_STABLE), 0,
clean_it->second.location + bmp_start * bitmap_granularity))
{
// need to wait. undo added requests, don't dequeue op
PRIV(read_op)->read_vec.clear();
return 0;
}
bmp_start = bmp_end;
}
}
}
}
}
else if (fulfilled < read_op->len)
{
// fill remaining parts with zeroes
fulfill_read(read_op, fulfilled, 0, block_size, (BS_ST_DELETE | BS_ST_STABLE), 0, 0);
}
assert(fulfilled == read_op->len);
read_op->version = result_version;
if (!PRIV(read_op)->pending_ops)
{
// everything is fulfilled from memory
if (!PRIV(read_op)->read_vec.size())
{
// region is not allocated - return zeroes
memset(read_op->buf, 0, read_op->len);
}
read_op->retval = read_op->len;
FINISH_OP(read_op);
return 1;
}
read_op->retval = 0;
return 1;
}
void blockstore_impl_t::handle_read_event(ring_data_t *data, blockstore_op_t *op)
{
live = true;
PRIV(op)->pending_ops--;
if (data->res != data->iov.iov_len)
{
// read error
op->retval = data->res;
}
if (PRIV(op)->pending_ops == 0)
{
if (op->retval == 0)
op->retval = op->len;
FINISH_OP(op);
}
}