diff options
| -rw-r--r-- | block/nbd.c | 52 |
1 files changed, 46 insertions, 6 deletions
diff --git a/block/nbd.c b/block/nbd.c index bea7acd213..9d661c1a92 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -277,8 +277,9 @@ static int nbd_open(BlockDriverState *bs, const char* filename, int flags) return result; } -static int nbd_co_readv(BlockDriverState *bs, int64_t sector_num, - int nb_sectors, QEMUIOVector *qiov) +static int nbd_co_readv_1(BlockDriverState *bs, int64_t sector_num, + int nb_sectors, QEMUIOVector *qiov, + int offset) { BDRVNBDState *s = bs->opaque; struct nbd_request request; @@ -292,15 +293,16 @@ static int nbd_co_readv(BlockDriverState *bs, int64_t sector_num, if (nbd_co_send_request(s, &request, NULL, 0) == -1) { reply.error = errno; } else { - nbd_co_receive_reply(s, &request, &reply, qiov->iov, 0); + nbd_co_receive_reply(s, &request, &reply, qiov->iov, offset); } nbd_coroutine_end(s, &request); return -reply.error; } -static int nbd_co_writev(BlockDriverState *bs, int64_t sector_num, - int nb_sectors, QEMUIOVector *qiov) +static int nbd_co_writev_1(BlockDriverState *bs, int64_t sector_num, + int nb_sectors, QEMUIOVector *qiov, + int offset) { BDRVNBDState *s = bs->opaque; struct nbd_request request; @@ -311,7 +313,7 @@ static int nbd_co_writev(BlockDriverState *bs, int64_t sector_num, request.len = nb_sectors * 512; nbd_coroutine_start(s, &request); - if (nbd_co_send_request(s, &request, qiov->iov, 0) == -1) { + if (nbd_co_send_request(s, &request, qiov->iov, offset) == -1) { reply.error = errno; } else { nbd_co_receive_reply(s, &request, &reply, NULL, 0); @@ -320,6 +322,44 @@ static int nbd_co_writev(BlockDriverState *bs, int64_t sector_num, return -reply.error; } +/* qemu-nbd has a limit of slightly less than 1M per request. Try to + * remain aligned to 4K. */ +#define NBD_MAX_SECTORS 2040 + +static int nbd_co_readv(BlockDriverState *bs, int64_t sector_num, + int nb_sectors, QEMUIOVector *qiov) +{ + int offset = 0; + int ret; + while (nb_sectors > NBD_MAX_SECTORS) { + ret = nbd_co_readv_1(bs, sector_num, NBD_MAX_SECTORS, qiov, offset); + if (ret < 0) { + return ret; + } + offset += NBD_MAX_SECTORS * 512; + sector_num += NBD_MAX_SECTORS; + nb_sectors -= NBD_MAX_SECTORS; + } + return nbd_co_readv_1(bs, sector_num, nb_sectors, qiov, offset); +} + +static int nbd_co_writev(BlockDriverState *bs, int64_t sector_num, + int nb_sectors, QEMUIOVector *qiov) +{ + int offset = 0; + int ret; + while (nb_sectors > NBD_MAX_SECTORS) { + ret = nbd_co_writev_1(bs, sector_num, NBD_MAX_SECTORS, qiov, offset); + if (ret < 0) { + return ret; + } + offset += NBD_MAX_SECTORS * 512; + sector_num += NBD_MAX_SECTORS; + nb_sectors -= NBD_MAX_SECTORS; + } + return nbd_co_writev_1(bs, sector_num, nb_sectors, qiov, offset); +} + static void nbd_close(BlockDriverState *bs) { BDRVNBDState *s = bs->opaque; |