diff options
| -rw-r--r-- | block/blklogwrites.c | 35 |
1 files changed, 26 insertions, 9 deletions
diff --git a/block/blklogwrites.c b/block/blklogwrites.c index 7207b2e757..ba717dab4d 100644 --- a/block/blklogwrites.c +++ b/block/blklogwrites.c @@ -328,22 +328,39 @@ static void coroutine_fn GRAPH_RDLOCK blk_log_writes_co_do_log(BlkLogWritesLogReq *lr) { BDRVBlkLogWritesState *s = lr->bs->opaque; - uint64_t cur_log_offset = s->cur_log_sector << s->sectorbits; - s->nr_entries++; - s->cur_log_sector += - ROUND_UP(lr->qiov->size, s->sectorsize) >> s->sectorbits; + /* + * Determine the offsets and sizes of different parts of the entry, and + * update the state of the driver. + * + * This needs to be done in one go, before any actual I/O is done, as the + * log entry may have to be written in two parts, and the state of the + * driver may be modified by other driver operations while waiting for the + * I/O to complete. + */ + const uint64_t entry_start_sector = s->cur_log_sector; + const uint64_t entry_offset = entry_start_sector << s->sectorbits; + const uint64_t qiov_aligned_size = ROUND_UP(lr->qiov->size, s->sectorsize); + const uint64_t entry_aligned_size = qiov_aligned_size + + ROUND_UP(lr->zero_size, s->sectorsize); + const uint64_t entry_nr_sectors = entry_aligned_size >> s->sectorbits; - lr->log_ret = bdrv_co_pwritev(s->log_file, cur_log_offset, lr->qiov->size, + s->nr_entries++; + s->cur_log_sector += entry_nr_sectors; + + /* + * Write the log entry. Note that if this is a "write zeroes" operation, + * only the entry header is written here, with the zeroing being done + * separately below. + */ + lr->log_ret = bdrv_co_pwritev(s->log_file, entry_offset, lr->qiov->size, lr->qiov, 0); /* Logging for the "write zeroes" operation */ if (lr->log_ret == 0 && lr->zero_size) { - cur_log_offset = s->cur_log_sector << s->sectorbits; - s->cur_log_sector += - ROUND_UP(lr->zero_size, s->sectorsize) >> s->sectorbits; + const uint64_t zeroes_offset = entry_offset + qiov_aligned_size; - lr->log_ret = bdrv_co_pwrite_zeroes(s->log_file, cur_log_offset, + lr->log_ret = bdrv_co_pwrite_zeroes(s->log_file, zeroes_offset, lr->zero_size, 0); } |