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Re: [Qemu-devel] [PATCH 21/21] block: add spice block device backend
From: |
Marc-André Lureau |
Subject: |
Re: [Qemu-devel] [PATCH 21/21] block: add spice block device backend |
Date: |
Wed, 20 Nov 2013 12:00:26 +0100 |
/note to self:
- add failing case where nbd channel isn't connected before and after
migration (do not wait for nbd init or disconnection)
On Mon, Nov 18, 2013 at 1:25 PM, Marc-André Lureau
<address@hidden> wrote:
> From: Marc-André Lureau <address@hidden>
>
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
> block/Makefile.objs | 1 +
> block/spicebd.c | 536
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 537 insertions(+)
> create mode 100644 block/spicebd.c
>
> diff --git a/block/Makefile.objs b/block/Makefile.objs
> index 4e8c91e..f49b7c3 100644
> --- a/block/Makefile.objs
> +++ b/block/Makefile.objs
> @@ -16,6 +16,7 @@ block-obj-$(CONFIG_CURL) += curl.o
> block-obj-$(CONFIG_RBD) += rbd.o
> block-obj-$(CONFIG_GLUSTERFS) += gluster.o
> block-obj-$(CONFIG_LIBSSH2) += ssh.o
> +common-obj-$(CONFIG_SPICE) += spicebd.o
> endif
>
> common-obj-y += stream.o
> diff --git a/block/spicebd.c b/block/spicebd.c
> new file mode 100644
> index 0000000..6b23b61
> --- /dev/null
> +++ b/block/spicebd.c
> @@ -0,0 +1,536 @@
> +/*
> + * Spice block backend for QEMU.
> + *
> + * Copyright (C) 2013 Red Hat, Inc.
> + * Author: Marc-André Lureau <address@hidden>
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> copy
> + * of this software and associated documentation files (the "Software"), to
> deal
> + * in the Software without restriction, including without limitation the
> rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <stdarg.h>
> +#include <spice/protocol.h>
> +
> +#include "nbd-client.h"
> +#include "ui/qemu-spice.h"
> +#include "block/block_int.h"
> +#include "qemu/sockets.h"
> +#include "qemu/uri.h"
> +#include "qapi/qmp/qint.h"
> +#include "sysemu/sysemu.h"
> +#include "sysemu/char.h"
> +#include "qmp-commands.h"
> +#include "sysemu/blockdev.h"
> +#include "migration/migration.h"
> +
> +#ifndef DEBUG_SPICE
> +#define DEBUG_SPICE 0
> +#endif
> +
> +#define SOCKET_CHR 0
> +#define SOCKET_NBD 1
> +
> +#define DPRINTF(fmt, ...) \
> + do { \
> + if (DEBUG_SPICE) { \
> + fprintf(stderr, "spicebd: %-15s " fmt "\n", \
> + __func__, ##__VA_ARGS__); \
> + } \
> + } while (0)
> +
> +typedef struct Buffer {
> + uint8_t data[4096];
> + uint8_t *p;
> + char left;
> +} Buffer;
> +
> +typedef struct BDRVSpiceState {
> + BlockDriverState *bs;
> + QEMUBH *bh;
> + NbdClientSession client;
> +
> + /* our spicechr-fd pipe */
> + int sv[2];
> + Buffer readb;
> + Buffer writeb;
> +
> + int aio_count;
> + CharDriverState *chr;
> + guint chr_watch;
> +
> + Coroutine *coroutine;
> + bool need_read;
> + bool need_write;
> + bool opened;
> + bool inmigrate;
> +} BDRVSpiceState;
> +
> +static void nbd_read_handler(void *opaque);
> +static void update_chr_handlers(BDRVSpiceState *s);
> +
> +static int parse_uri(const char *filename, QDict *options, Error **errp)
> +{
> + URI *uri = NULL;
> +
> + uri = uri_parse(filename);
> + if (!uri) {
> + return -EINVAL;
> + }
> +
> + if (strcmp(uri->scheme, "spicebd") != 0) {
> + error_setg(errp, "URI scheme must be 'spicebd'");
> + goto err;
> + }
> +
> + uri_free(uri);
> + return 0;
> +
> + err:
> + if (uri) {
> + uri_free(uri);
> + }
> + return -EINVAL;
> +}
> +
> +static void spice_parse_filename(const char *filename, QDict *options,
> + Error **errp)
> +{
> + parse_uri(filename, options, errp);
> +}
> +
> +static void co_restart(void *opaque)
> +{
> + BDRVSpiceState *s = opaque;
> +
> + qemu_coroutine_enter(s->coroutine, NULL);
> +}
> +
> +static void close_socketpair(BDRVSpiceState *s)
> +{
> + if (!s->opened) {
> + return;
> + }
> +
> + DPRINTF("");
> + nbd_client_session_close(&s->client);
> +
> + if (s->sv[SOCKET_NBD] >= 0) {
> + qemu_aio_set_fd_handler(s->sv[SOCKET_NBD], NULL, NULL, NULL);
> + closesocket(s->sv[SOCKET_NBD]);
> + s->sv[SOCKET_NBD] = -1;
> + }
> +
> + if (s->sv[SOCKET_CHR] >= 0) {
> + qemu_aio_set_fd_handler(s->sv[SOCKET_CHR], NULL, NULL, NULL);
> + closesocket(s->sv[SOCKET_CHR]);
> + s->sv[SOCKET_CHR] = -1;
> + }
> +
> + if (s->inmigrate) {
> + vm_start_release();
> + s->inmigrate = false;
> + }
> +
> + s->opened = FALSE;
> + if (s->coroutine && s->coroutine != qemu_coroutine_self()) {
> + co_restart(s);
> + }
> +}
> +
> +static int chardev_can_read(void *opaque)
> +{
> + BDRVSpiceState *s = opaque;
> + int retval = 0;
> +
> + GPollFD pfd = {
> + .fd = s->sv[SOCKET_CHR],
> + .events = G_IO_OUT
> + };
> + g_poll(&pfd, 1, 0);
> + if (pfd.revents & G_IO_OUT) {
> + retval = s->writeb.left == 0 ? sizeof(s->writeb.data) : 0;
> + }
> +
> + return retval;
> +}
> +
> +static void chardev_read(void *opaque, const uint8_t *buf, int size)
> +{
> + BDRVSpiceState *s = opaque;
> + int written;
> +
> + DPRINTF("reply from client %d", size);
> + written = write(s->sv[SOCKET_CHR], buf, size);
> + if (written == -1) {
> + if (errno != EAGAIN) {
> + close_socketpair(s);
> + return;
> + } else {
> + written = 0;
> + }
> + }
> +
> + if (s->writeb.left == 0) {
> + size -= written;
> + assert(size <= sizeof(s->writeb.data));
> + memcpy(s->writeb.data, buf, size);
> + s->writeb.p = s->writeb.data;
> + s->writeb.left = size;
> + } else {
> + s->writeb.left -= written;
> + s->writeb.p += written;
> + }
> +
> + s->need_write = s->writeb.left > 0;
> + update_chr_handlers(s);
> +}
> +
> +static void change_blockdev_cb(void *opaque)
> +{
> + BDRVSpiceState *s = opaque;
> + BlockDriverState *bs = s->bs;
> + Error *err = NULL;
> + int bdrv_flags;
> + QDict *options = NULL;
> + char device_name[32];
> +
> + qemu_bh_delete(s->bh);
> + s->bh = NULL;
> +
> + memcpy(device_name, bs->child_device_name, sizeof(device_name));
> + DPRINTF("set bs %p to NULL", bs);
> + bs->opaque = NULL;
> +
> + bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
> + if (bdrv_is_snapshot(bs)) {
> + bdrv_flags |= BDRV_O_SNAPSHOT;
> + options = qdict_new();
> + qdict_put(options, "snapshot.size", qint_from_int(s->client.size));
> + }
> +
> + qmp_eject(device_name, true, true, &err);
> + if (error_is_set(&err)) {
> + fprintf(stderr, "spicebd: %s\n", error_get_pretty(err));
> + error_free(err);
> + QDECREF(options);
> + free(s);
> + }
> +
> + qmp_change_blockdev_int(device_name, "spicebd:", NULL,
> + options, s, &err);
> + if (error_is_set(&err)) {
> + fprintf(stderr, "spicebd: %s\n", error_get_pretty(err));
> + error_free(err);
> + }
> +
> + if (s->inmigrate) {
> + vm_start_release();
> + s->inmigrate = false;
> + }
> +}
> +
> +static void coroutine_fn co_init(void *opaque)
> +{
> + BDRVSpiceState *s = opaque;
> + BlockDriverState *bs = s->bs;
> +
> + DPRINTF("temporary coroutine for session initialization %p, "
> + "device: %s", s, bs->child_device_name);
> +
> + qemu_set_nonblock(s->sv[SOCKET_NBD]);
> + /* After session_init, the fd_handler is managed by nbd-client */
> + qemu_aio_set_fd_handler(s->sv[SOCKET_NBD], co_restart, NULL, s);
> + if (nbd_client_session_init(&s->client, bs,
> + s->sv[SOCKET_NBD], NULL) < 0) {
> + close_socketpair(s);
> + } else {
> + assert(s->bh == NULL);
> + /* NOTE: need to defer out of current AIO call, to avoid non-blocking
> + drain_all when ejecting? */
> + s->bh = qemu_bh_new(change_blockdev_cb, s);
> + qemu_bh_schedule(s->bh);
> + }
> +
> + s->coroutine = NULL;
> + DPRINTF("end of temporary coroutine");
> +}
> +
> +static void spice_init(BDRVSpiceState *s)
> +{
> + if (s->opened) {
> + return;
> + }
> +
> + s->opened = TRUE;
> +
> + /* TODO: teach nbd to use a iostream api instead of a socket */
> + if (socketpair(PF_UNIX, SOCK_STREAM, 0, s->sv) == -1) {
> + fprintf(stderr, "failed to create socketpair\n");
> + return;
> + }
> +
> + s->need_read = TRUE;
> + update_chr_handlers(s);
> +
> + if (runstate_check(RUN_STATE_INMIGRATE)) {
> + vm_start_hold();
> + s->inmigrate = true;
> + }
> +
> + /* tell server we are ready */
> + qemu_chr_fe_event(s->chr, SPICE_PORT_EVENT_OPENED);
> + s->coroutine = qemu_coroutine_create(co_init);
> + qemu_coroutine_enter(s->coroutine, s);
> +}
> +
> +static void chardev_event(void *opaque, int event)
> +{
> + BDRVSpiceState *s = opaque;
> +
> + switch (event) {
> + case CHR_EVENT_CLOSED:
> + DPRINTF("chardev close");
> + close_socketpair(s);
> + break;
> + case CHR_EVENT_BREAK:
> + DPRINTF("chardev break");
> + if (s->coroutine) {
> + DPRINTF("already waiting for incoming session");
> + qemu_chr_fe_event(s->chr, SPICE_PORT_EVENT_OPENED);
> + return;
> + }
> + close_socketpair(s);
> + /* fall-through */
> + case CHR_EVENT_OPENED:
> + DPRINTF("chardev opened");
> + spice_init(s);
> + break;
> + default:
> + DPRINTF("unhandled chardev event %d", event);
> + }
> +}
> +
> +static gboolean write_to_chr(GIOChannel *chan, GIOCondition cond,
> + void *opaque)
> +{
> + BDRVSpiceState *s = opaque;
> + int r;
> +
> + r = qemu_chr_fe_write(s->chr, s->readb.p, s->readb.left);
> + DPRINTF("write_to_chr %d/%d", r, s->readb.left);
> + if (r <= 0) {
> + close_socketpair(s);
> + return FALSE;
> + }
> +
> + s->readb.p += r;
> + s->readb.left -= r;
> +
> + if (s->readb.left > 0) {
> + if (!s->chr_watch) {
> + s->chr_watch = qemu_chr_fe_add_watch(s->chr, G_IO_OUT,
> + write_to_chr, s);
> + }
> + return TRUE;
> + } else {
> + s->need_read = TRUE;
> + update_chr_handlers(s);
> + }
> +
> + return FALSE;
> +}
> +
> +static void nbd_read_handler(void *opaque)
> +{
> + BDRVSpiceState *s = opaque;
> +
> + DPRINTF("read from nbd");
> +
> + if (s->readb.left > 0) {
> + abort();
> + }
> +
> + do {
> + s->readb.left = recv(s->sv[SOCKET_CHR], s->readb.data,
> + sizeof(s->readb.data), MSG_DONTWAIT);
> + } while (s->readb.left == -1 && errno == EAGAIN);
> +
> + if (s->readb.left <= 0) {
> + close_socketpair(s);
> + return;
> + }
> +
> + s->need_read = FALSE;
> + update_chr_handlers(s);
> +
> + s->readb.p = s->readb.data;
> + write_to_chr(NULL, 0, s);
> +}
> +
> +static void nbd_write_handler(void *opaque)
> +{
> + BDRVSpiceState *s = opaque;
> +
> + DPRINTF("resuming chardev_read left: %d", s->writeb.left);
> +
> + chardev_read(s, s->writeb.data, s->writeb.left);
> +}
> +
> +static void update_chr_handlers(BDRVSpiceState *s)
> +{
> + qemu_aio_set_fd_handler(s->sv[SOCKET_CHR],
> + s->need_read ? nbd_read_handler : NULL,
> + s->need_write ? nbd_write_handler : NULL,
> + s);
> +}
> +
> +static int spice_file_open(BlockDriverState *bs, QDict *options, int
> bdrv_flags,
> + Error **errp)
> +{
> + BDRVSpiceState *s = bs->opaque;
> + int ret = -1;
> +
> + s->bs = bs;
> +
> + if (s->opened) {
> + DPRINTF("re-open spicebd");
> + s->client.bs = bs;
> + return 0;
> + }
> +
> + DPRINTF("open %p device=%s flags=0x%x", s,
> + bs->child_device_name, bdrv_flags);
> + if (strlen(bs->child_device_name) == 0) {
> + fprintf(stderr, "spicebd: missing associated child device\n");
> + return -1;
> + }
> +
> + if (bdrv_flags & BDRV_O_RDWR) {
> + fprintf(stderr, "spicebd: only read-only supported\n");
> + return -1;
> + }
> +
> + s->chr = qemu_chr_open_spice_vmc("nbd", true);
> + if (!s->chr) {
> + goto err;
> + }
> +
> + qemu_chr_add_handlers(s->chr, chardev_can_read,
> + chardev_read, chardev_event, s);
> + spice_init(s);
> +
> + return 0;
> +
> + err:
> + return ret;
> +}
> +
> +static void spice_close(BlockDriverState *bs)
> +{
> + BDRVSpiceState *s = bs->opaque;
> +
> + DPRINTF("spice close %p\n", s);
> +
> + if (s == NULL) {
> + /* changing bd */
> + return;
> + }
> +
> + s->bs = NULL;
> +
> + close_socketpair(s);
> + assert(!s->coroutine); /* after close_socketpair */
> +
> + if (s->chr) {
> + s->chr->chr_close(s->chr);
> + g_free(s->chr);
> + s->chr = NULL;
> + }
> +}
> +
> +static coroutine_fn int spice_co_readv(BlockDriverState *bs,
> + int64_t sector_num,
> + int nb_sectors, QEMUIOVector *qiov)
> +{
> + BDRVSpiceState *s = bs->opaque;
> +
> + return nbd_client_session_co_readv(&s->client, sector_num,
> + nb_sectors, qiov);
> +}
> +
> +static coroutine_fn int spice_co_writev(BlockDriverState *bs,
> + int64_t sector_num,
> + int nb_sectors, QEMUIOVector *qiov)
> +{
> + BDRVSpiceState *s = bs->opaque;
> +
> + return nbd_client_session_co_writev(&s->client, sector_num,
> + nb_sectors, qiov);
> +}
> +
> +static coroutine_fn int spice_co_flush(BlockDriverState *bs)
> +{
> + BDRVSpiceState *s = bs->opaque;
> +
> + if (s == NULL) {
> + /* changing bd */
> + return -1;
> + }
> +
> + return nbd_client_session_co_flush(&s->client);
> +}
> +
> +static coroutine_fn int spice_co_discard(BlockDriverState *bs,
> + int64_t sector_num, int nb_sectors)
> +{
> + BDRVSpiceState *s = bs->opaque;
> +
> + return nbd_client_session_co_discard(&s->client, sector_num, nb_sectors);
> +}
> +
> +static coroutine_fn int64_t spice_getlength(BlockDriverState *bs)
> +{
> + BDRVSpiceState *s = bs->opaque;
> +
> + DPRINTF("length=%" PRIi64, s->client.size);
> +
> + return s->client.size;
> +}
> +
> +static BlockDriver bdrv_spice = {
> + .format_name = "spicebd",
> + .protocol_name = "spicebd",
> + .instance_size = sizeof(BDRVSpiceState),
> + .bdrv_parse_filename = spice_parse_filename,
> + .bdrv_file_open = spice_file_open,
> + .bdrv_close = spice_close,
> + .bdrv_co_readv = spice_co_readv,
> + .bdrv_co_writev = spice_co_writev,
> + .bdrv_getlength = spice_getlength,
> + .bdrv_co_flush_to_os = spice_co_flush,
> + .bdrv_co_discard = spice_co_discard,
> +};
> +
> +static void bdrv_spice_init(void)
> +{
> + bdrv_register(&bdrv_spice);
> +}
> +
> +block_init(bdrv_spice_init);
> --
> 1.8.3.1
>
--
Marc-André Lureau
- [Qemu-devel] [PATCH 13/21] blockdev: add qmp_change_blockdev_int(), (continued)
- [Qemu-devel] [PATCH 13/21] blockdev: add qmp_change_blockdev_int(), Marc-André Lureau, 2013/11/18
- [Qemu-devel] [PATCH 14/21] block: extract make_snapshot() from bdrv_open(), Marc-André Lureau, 2013/11/18
- [Qemu-devel] [PATCH 15/21] block: add "snapshot.size" option to avoid extra bdrv_open(), Marc-André Lureau, 2013/11/18
- [Qemu-devel] [PATCH 16/21] block: learn to open a driver with a given opaque, Marc-André Lureau, 2013/11/18
- [Qemu-devel] [PATCH 17/21] block: allow to call bdrv_open() with an opaque, Marc-André Lureau, 2013/11/18
- [Qemu-devel] [PATCH 18/21] block: do not notify change during migration, Marc-André Lureau, 2013/11/18
- [Qemu-devel] [PATCH 19/21] sysemu: add vm_start_hold/release, Marc-André Lureau, 2013/11/18
- [Qemu-devel] [PATCH 20/21] spice-core: allow an interface to be in AIO context, Marc-André Lureau, 2013/11/18
- [Qemu-devel] [PATCH 21/21] block: add spice block device backend, Marc-André Lureau, 2013/11/18
- Re: [Qemu-devel] [PATCH 21/21] block: add spice block device backend,
Marc-André Lureau <=
- Re: [Qemu-devel] [PATCH 00/21] RFCv2: add Spice block device, Marc-André Lureau, 2013/11/22