From: Eric Blake <ebl...@redhat.com> If nbd_client_init() fails after we are already connected, then the server will spam logs with:
Disconnect client, due to: Unexpected end-of-file before all bytes were read unless we gracefully disconnect before closing the connection. Ways to trigger this: $ opts=driver=nbd,export=foo,server.type=inet,server.host=localhost,server.port=10809 $ qemu-img map --output=json --image-opts $opts,read-only=off $ qemu-img map --output=json --image-opts $opts,x-dirty-bitmap=nosuch: Signed-off-by: Eric Blake <ebl...@redhat.com> Message-Id: <20181130023232.3079982-4-ebl...@redhat.com> Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com> (cherry picked from commit c688e6ca7b41a105241054853d250df64addbf8f) *drop functional dep. on 6c2e581d4d7 Signed-off-by: Michael Roth <mdr...@linux.vnet.ibm.com> --- block/nbd-client.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/block/nbd-client.c b/block/nbd-client.c index f8c42a6996..1b7b5b0a88 100644 --- a/block/nbd-client.c +++ b/block/nbd-client.c @@ -995,13 +995,15 @@ int nbd_client_init(BlockDriverState *bs, if (x_dirty_bitmap && !client->info.base_allocation) { error_setg(errp, "requested x-dirty-bitmap %s not found", x_dirty_bitmap); - return -EINVAL; + ret = -EINVAL; + goto fail; } if (client->info.flags & NBD_FLAG_READ_ONLY && !bdrv_is_read_only(bs)) { error_setg(errp, "request for write access conflicts with read-only export"); - return -EACCES; + ret = -EACCES; + goto fail; } if (client->info.flags & NBD_FLAG_SEND_FUA) { bs->supported_write_flags = BDRV_REQ_FUA; @@ -1029,4 +1031,17 @@ int nbd_client_init(BlockDriverState *bs, logout("Established connection with NBD server\n"); return 0; + + fail: + /* + * We have connected, but must fail for other reasons. The + * connection is still blocking; send NBD_CMD_DISC as a courtesy + * to the server. + */ + { + NBDRequest request = { .type = NBD_CMD_DISC }; + + nbd_send_request(client->ioc ?: QIO_CHANNEL(sioc), &request); + return ret; + } } -- 2.17.1