It's incorrect to return success rc >= 0 if we skip qio_channel_writev_all() call due to s->quit. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-Id: <20170920124507.18841-4-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake <eblake@redhat.com>
417 lines
12 KiB
C
417 lines
12 KiB
C
/*
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* QEMU Block driver for NBD
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*
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* Copyright (C) 2016 Red Hat, Inc.
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* Copyright (C) 2008 Bull S.A.S.
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* Author: Laurent Vivier <Laurent.Vivier@bull.net>
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*
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* Some parts:
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* Copyright (C) 2007 Anthony Liguori <anthony@codemonkey.ws>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu/osdep.h"
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#include "qapi/error.h"
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#include "nbd-client.h"
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#define HANDLE_TO_INDEX(bs, handle) ((handle) ^ (uint64_t)(intptr_t)(bs))
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#define INDEX_TO_HANDLE(bs, index) ((index) ^ (uint64_t)(intptr_t)(bs))
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static void nbd_recv_coroutines_wake_all(NBDClientSession *s)
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{
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int i;
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for (i = 0; i < MAX_NBD_REQUESTS; i++) {
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NBDClientRequest *req = &s->requests[i];
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if (req->coroutine && req->receiving) {
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aio_co_wake(req->coroutine);
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}
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}
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}
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static void nbd_teardown_connection(BlockDriverState *bs)
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{
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NBDClientSession *client = nbd_get_client_session(bs);
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if (!client->ioc) { /* Already closed */
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return;
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}
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/* finish any pending coroutines */
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qio_channel_shutdown(client->ioc,
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QIO_CHANNEL_SHUTDOWN_BOTH,
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NULL);
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BDRV_POLL_WHILE(bs, client->read_reply_co);
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nbd_client_detach_aio_context(bs);
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object_unref(OBJECT(client->sioc));
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client->sioc = NULL;
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object_unref(OBJECT(client->ioc));
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client->ioc = NULL;
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}
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static coroutine_fn void nbd_read_reply_entry(void *opaque)
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{
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NBDClientSession *s = opaque;
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uint64_t i;
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int ret = 0;
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Error *local_err = NULL;
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while (!s->quit) {
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assert(s->reply.handle == 0);
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ret = nbd_receive_reply(s->ioc, &s->reply, &local_err);
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if (ret < 0) {
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error_report_err(local_err);
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}
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if (ret <= 0) {
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break;
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}
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/* There's no need for a mutex on the receive side, because the
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* handler acts as a synchronization point and ensures that only
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* one coroutine is called until the reply finishes.
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*/
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i = HANDLE_TO_INDEX(s, s->reply.handle);
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if (i >= MAX_NBD_REQUESTS ||
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!s->requests[i].coroutine ||
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!s->requests[i].receiving) {
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break;
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}
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/* We're woken up again by the request itself. Note that there
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* is no race between yielding and reentering read_reply_co. This
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* is because:
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*
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* - if the request runs on the same AioContext, it is only
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* entered after we yield
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*
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* - if the request runs on a different AioContext, reentering
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* read_reply_co happens through a bottom half, which can only
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* run after we yield.
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*/
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aio_co_wake(s->requests[i].coroutine);
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qemu_coroutine_yield();
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}
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s->quit = true;
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nbd_recv_coroutines_wake_all(s);
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s->read_reply_co = NULL;
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}
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static int nbd_co_send_request(BlockDriverState *bs,
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NBDRequest *request,
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QEMUIOVector *qiov)
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{
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NBDClientSession *s = nbd_get_client_session(bs);
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int rc, i;
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qemu_co_mutex_lock(&s->send_mutex);
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while (s->in_flight == MAX_NBD_REQUESTS) {
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qemu_co_queue_wait(&s->free_sema, &s->send_mutex);
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}
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s->in_flight++;
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for (i = 0; i < MAX_NBD_REQUESTS; i++) {
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if (s->requests[i].coroutine == NULL) {
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break;
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}
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}
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g_assert(qemu_in_coroutine());
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assert(i < MAX_NBD_REQUESTS);
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s->requests[i].coroutine = qemu_coroutine_self();
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s->requests[i].receiving = false;
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request->handle = INDEX_TO_HANDLE(s, i);
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if (s->quit) {
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rc = -EIO;
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goto err;
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}
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if (!s->ioc) {
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rc = -EPIPE;
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goto err;
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}
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if (qiov) {
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qio_channel_set_cork(s->ioc, true);
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rc = nbd_send_request(s->ioc, request);
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if (rc >= 0 && !s->quit) {
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assert(request->len == iov_size(qiov->iov, qiov->niov));
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if (qio_channel_writev_all(s->ioc, qiov->iov, qiov->niov,
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NULL) < 0) {
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rc = -EIO;
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}
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} else if (rc >= 0) {
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rc = -EIO;
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}
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qio_channel_set_cork(s->ioc, false);
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} else {
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rc = nbd_send_request(s->ioc, request);
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}
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err:
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if (rc < 0) {
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s->quit = true;
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s->requests[i].coroutine = NULL;
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s->in_flight--;
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qemu_co_queue_next(&s->free_sema);
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}
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qemu_co_mutex_unlock(&s->send_mutex);
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return rc;
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}
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static int nbd_co_receive_reply(NBDClientSession *s,
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NBDRequest *request,
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QEMUIOVector *qiov)
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{
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int ret;
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int i = HANDLE_TO_INDEX(s, request->handle);
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/* Wait until we're woken up by nbd_read_reply_entry. */
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s->requests[i].receiving = true;
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qemu_coroutine_yield();
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s->requests[i].receiving = false;
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if (!s->ioc || s->quit) {
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ret = -EIO;
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} else {
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assert(s->reply.handle == request->handle);
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ret = -s->reply.error;
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if (qiov && s->reply.error == 0) {
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assert(request->len == iov_size(qiov->iov, qiov->niov));
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if (qio_channel_readv_all(s->ioc, qiov->iov, qiov->niov,
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NULL) < 0) {
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ret = -EIO;
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s->quit = true;
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}
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}
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/* Tell the read handler to read another header. */
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s->reply.handle = 0;
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}
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s->requests[i].coroutine = NULL;
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/* Kick the read_reply_co to get the next reply. */
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if (s->read_reply_co) {
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aio_co_wake(s->read_reply_co);
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}
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qemu_co_mutex_lock(&s->send_mutex);
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s->in_flight--;
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qemu_co_queue_next(&s->free_sema);
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qemu_co_mutex_unlock(&s->send_mutex);
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return ret;
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}
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static int nbd_co_request(BlockDriverState *bs,
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NBDRequest *request,
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QEMUIOVector *qiov)
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{
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NBDClientSession *client = nbd_get_client_session(bs);
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int ret;
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assert(!qiov || request->type == NBD_CMD_WRITE ||
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request->type == NBD_CMD_READ);
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ret = nbd_co_send_request(bs, request,
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request->type == NBD_CMD_WRITE ? qiov : NULL);
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if (ret < 0) {
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return ret;
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}
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return nbd_co_receive_reply(client, request,
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request->type == NBD_CMD_READ ? qiov : NULL);
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}
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int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
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uint64_t bytes, QEMUIOVector *qiov, int flags)
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{
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NBDRequest request = {
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.type = NBD_CMD_READ,
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.from = offset,
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.len = bytes,
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};
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assert(bytes <= NBD_MAX_BUFFER_SIZE);
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assert(!flags);
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return nbd_co_request(bs, &request, qiov);
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}
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int nbd_client_co_pwritev(BlockDriverState *bs, uint64_t offset,
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uint64_t bytes, QEMUIOVector *qiov, int flags)
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{
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NBDClientSession *client = nbd_get_client_session(bs);
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NBDRequest request = {
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.type = NBD_CMD_WRITE,
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.from = offset,
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.len = bytes,
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};
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if (flags & BDRV_REQ_FUA) {
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assert(client->info.flags & NBD_FLAG_SEND_FUA);
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request.flags |= NBD_CMD_FLAG_FUA;
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}
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assert(bytes <= NBD_MAX_BUFFER_SIZE);
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return nbd_co_request(bs, &request, qiov);
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}
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int nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
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int bytes, BdrvRequestFlags flags)
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{
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NBDClientSession *client = nbd_get_client_session(bs);
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NBDRequest request = {
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.type = NBD_CMD_WRITE_ZEROES,
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.from = offset,
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.len = bytes,
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};
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if (!(client->info.flags & NBD_FLAG_SEND_WRITE_ZEROES)) {
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return -ENOTSUP;
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}
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if (flags & BDRV_REQ_FUA) {
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assert(client->info.flags & NBD_FLAG_SEND_FUA);
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request.flags |= NBD_CMD_FLAG_FUA;
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}
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if (!(flags & BDRV_REQ_MAY_UNMAP)) {
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request.flags |= NBD_CMD_FLAG_NO_HOLE;
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}
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return nbd_co_request(bs, &request, NULL);
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}
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int nbd_client_co_flush(BlockDriverState *bs)
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{
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NBDClientSession *client = nbd_get_client_session(bs);
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NBDRequest request = { .type = NBD_CMD_FLUSH };
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if (!(client->info.flags & NBD_FLAG_SEND_FLUSH)) {
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return 0;
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}
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request.from = 0;
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request.len = 0;
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return nbd_co_request(bs, &request, NULL);
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}
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int nbd_client_co_pdiscard(BlockDriverState *bs, int64_t offset, int bytes)
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{
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NBDClientSession *client = nbd_get_client_session(bs);
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NBDRequest request = {
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.type = NBD_CMD_TRIM,
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.from = offset,
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.len = bytes,
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};
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if (!(client->info.flags & NBD_FLAG_SEND_TRIM)) {
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return 0;
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}
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return nbd_co_request(bs, &request, NULL);
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}
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void nbd_client_detach_aio_context(BlockDriverState *bs)
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{
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NBDClientSession *client = nbd_get_client_session(bs);
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qio_channel_detach_aio_context(QIO_CHANNEL(client->ioc));
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}
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void nbd_client_attach_aio_context(BlockDriverState *bs,
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AioContext *new_context)
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{
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NBDClientSession *client = nbd_get_client_session(bs);
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qio_channel_attach_aio_context(QIO_CHANNEL(client->ioc), new_context);
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aio_co_schedule(new_context, client->read_reply_co);
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}
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void nbd_client_close(BlockDriverState *bs)
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{
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NBDClientSession *client = nbd_get_client_session(bs);
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NBDRequest request = { .type = NBD_CMD_DISC };
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if (client->ioc == NULL) {
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return;
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}
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nbd_send_request(client->ioc, &request);
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nbd_teardown_connection(bs);
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}
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int nbd_client_init(BlockDriverState *bs,
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QIOChannelSocket *sioc,
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const char *export,
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QCryptoTLSCreds *tlscreds,
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const char *hostname,
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Error **errp)
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{
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NBDClientSession *client = nbd_get_client_session(bs);
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int ret;
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/* NBD handshake */
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logout("session init %s\n", export);
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qio_channel_set_blocking(QIO_CHANNEL(sioc), true, NULL);
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client->info.request_sizes = true;
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ret = nbd_receive_negotiate(QIO_CHANNEL(sioc), export,
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tlscreds, hostname,
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&client->ioc, &client->info, errp);
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if (ret < 0) {
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logout("Failed to negotiate with the NBD server\n");
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return ret;
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}
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if (client->info.flags & NBD_FLAG_SEND_FUA) {
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bs->supported_write_flags = BDRV_REQ_FUA;
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bs->supported_zero_flags |= BDRV_REQ_FUA;
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}
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if (client->info.flags & NBD_FLAG_SEND_WRITE_ZEROES) {
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bs->supported_zero_flags |= BDRV_REQ_MAY_UNMAP;
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}
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if (client->info.min_block > bs->bl.request_alignment) {
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bs->bl.request_alignment = client->info.min_block;
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}
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qemu_co_mutex_init(&client->send_mutex);
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qemu_co_queue_init(&client->free_sema);
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client->sioc = sioc;
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object_ref(OBJECT(client->sioc));
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if (!client->ioc) {
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client->ioc = QIO_CHANNEL(sioc);
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object_ref(OBJECT(client->ioc));
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}
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/* Now that we're connected, set the socket to be non-blocking and
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* kick the reply mechanism. */
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qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL);
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client->read_reply_co = qemu_coroutine_create(nbd_read_reply_entry, client);
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nbd_client_attach_aio_context(bs, bdrv_get_aio_context(bs));
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logout("Established connection with NBD server\n");
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return 0;
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}
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