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Re: [Qemu-block] [PATCH 10/10] scsi: add persistent reservation manager
From: |
Fam Zheng |
Subject: |
Re: [Qemu-block] [PATCH 10/10] scsi: add persistent reservation manager using qemu-pr-helper |
Date: |
Wed, 23 Aug 2017 12:49:26 +0800 |
User-agent: |
Mutt/1.8.3 (2017-05-23) |
On Tue, 08/22 15:18, Paolo Bonzini wrote:
> This adds a concrete subclass of pr-manager that talks to qemu-pr-helper.
>
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
> scsi/Makefile.objs | 2 +-
> scsi/pr-manager-helper.c | 288
> +++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 289 insertions(+), 1 deletion(-)
> create mode 100644 scsi/pr-manager-helper.c
>
> diff --git a/scsi/Makefile.objs b/scsi/Makefile.objs
> index 5496d2ae6a..4d25e476cf 100644
> --- a/scsi/Makefile.objs
> +++ b/scsi/Makefile.objs
> @@ -1,3 +1,3 @@
> block-obj-y += utils.o
>
> -block-obj-$(CONFIG_LINUX) += pr-manager.o
> +block-obj-$(CONFIG_LINUX) += pr-manager.o pr-manager-helper.o
> diff --git a/scsi/pr-manager-helper.c b/scsi/pr-manager-helper.c
> new file mode 100644
> index 0000000000..c9d9606696
> --- /dev/null
> +++ b/scsi/pr-manager-helper.c
> @@ -0,0 +1,288 @@
> +/*
> + * Persistent reservation manager that talks to qemu-mpath-helper
s/qemu-mpath-helper/qemu-pr-helper/
> + *
> + * Copyright (c) 2017 Red Hat, Inc.
Since I'm commenting on a header, just BTW I was educated that (c) stands for
"copyright" so this is actually a ubiquitous redundancy. :)
> + *
> + * Author: Paolo Bonzini <address@hidden>
> + *
> + * This code is licensed under the LGPL.
Interesting, I think the version of the license is required?
> + *
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qapi/error.h"
> +#include "scsi/constants.h"
> +#include "scsi/pr-manager.h"
> +#include "scsi/utils.h"
> +#include "io/channel.h"
> +#include "io/channel-socket.h"
> +#include "pr-helper.h"
> +
> +#include <scsi/sg.h>
> +
> +#define PR_MAX_RECONNECT_ATTEMPTS 5
> +
> +#define TYPE_PR_MANAGER_HELPER "pr-manager-helper"
> +
> +#define PR_MANAGER_HELPER(obj) \
> + INTERFACE_CHECK(PRManagerHelper, (obj), \
> + TYPE_PR_MANAGER_HELPER)
> +
> +typedef struct PRManagerHelper {
> + /* <private> */
> + PRManager parent;
> +
> + char *path;
> +
> + QemuMutex lock;
> + QIOChannel *ioc;
> +} PRManagerHelper;
> +
> +/* Called with lock held. */
> +static int pr_manager_helper_read(PRManagerHelper *pr_mgr,
> + void *buf, int sz, Error **errp)
> +{
> + ssize_t r = qio_channel_read_all(pr_mgr->ioc, buf, sz, errp);
> +
> + if (r < 0) {
> + object_unref(OBJECT(pr_mgr->ioc));
> + pr_mgr->ioc = NULL;
> + return r;
> + }
> +
> + return r < 0 ? r : 0;
> +}
> +
> +/* Called with lock held. */
> +static int pr_manager_helper_write(PRManagerHelper *pr_mgr,
> + int fd,
> + const void *buf, int sz, Error **errp)
> +{
> + size_t nfds = (fd != -1);
> + while (sz > 0) {
> + struct iovec iov;
> + ssize_t n_written;
> +
> + iov.iov_base = (void *)buf;
> + iov.iov_len = sz;
> + n_written = qio_channel_writev_full(QIO_CHANNEL(pr_mgr->ioc), &iov,
> 1,
> + nfds ? &fd : NULL, nfds, errp);
> +
> + if (n_written <= 0) {
> + assert(n_written != QIO_CHANNEL_ERR_BLOCK);
> + object_unref(OBJECT(pr_mgr->ioc));
> + pr_mgr->ioc = NULL;
> + return n_written;
> + }
> +
> + nfds = 0;
> + buf += n_written;
> + sz -= n_written;
> + }
> +
> + return 0;
> +}
> +
> +/* Called with lock held. */
> +static int pr_manager_helper_initialize(PRManagerHelper *pr_mgr,
> + Error **errp)
> +{
> + uint32_t flags;
> +
> + SocketAddress saddr = {
> + .type = SOCKET_ADDRESS_TYPE_UNIX,
> + .u.q_unix.path = g_strdup(pr_mgr->path)
Missing g_free()?
> + };
> + QIOChannelSocket *sioc = qio_channel_socket_new();
> + Error *local_err = NULL;
> +
> + qio_channel_set_name(QIO_CHANNEL(sioc), "pr-manager-helper");
> + qio_channel_socket_connect_sync(sioc,
> + &saddr,
> + &local_err);
> + if (local_err) {
> + object_unref(OBJECT(sioc));
> + error_propagate(errp, local_err);
> + return -ENOTCONN;
> + }
> +
> + qio_channel_set_delay(QIO_CHANNEL(sioc), false);
> + pr_mgr->ioc = QIO_CHANNEL(sioc);
> +
> + /* A simple feature negotation protocol, even though there is
> + * no optional feature right now.
> + */
> + if (pr_manager_helper_read(pr_mgr, &flags, sizeof(flags), errp) < 0) {
Not returning the return value of pr_manager_helper_read()?.
> + return -EINVAL;
> + }
> +
> + flags = 0;
> + if (pr_manager_helper_write(pr_mgr, -1, &flags, sizeof(flags), errp) <
> 0) {
> + return -EINVAL;
Same here.
> + }
> +
> + return 0;
> +}
> +
> +static int pr_manager_helper_run(PRManager *p,
> + int fd, struct sg_io_hdr *io_hdr)
> +{
> + PRManagerHelper *pr_mgr = PR_MANAGER_HELPER(p);
> +
> + uint32_t len;
> + PRHelperResponse resp;
> + int ret;
> + int expected_dir;
> + int attempts;
> + uint8_t cdb[PR_HELPER_CDB_SIZE] = { 0 };
> +
> + if (!io_hdr->cmd_len || io_hdr->cmd_len > PR_HELPER_CDB_SIZE) {
> + return -EINVAL;
> + }
> +
> + memcpy(cdb, io_hdr->cmdp, io_hdr->cmd_len);
> + assert(cdb[0] == PERSISTENT_RESERVE_OUT || cdb[0] ==
> PERSISTENT_RESERVE_IN);
> + expected_dir =
> + (cdb[0] == PERSISTENT_RESERVE_OUT ? SG_DXFER_TO_DEV :
> SG_DXFER_FROM_DEV);
> + if (io_hdr->dxfer_direction != expected_dir) {
> + return -EINVAL;
> + }
> +
> + len = scsi_cdb_xfer(cdb);
> + if (io_hdr->dxfer_len < len || len > PR_HELPER_DATA_SIZE) {
> + return -EINVAL;
> + }
> +
> + ret = 0;
> + qemu_mutex_lock(&pr_mgr->lock);
> +
> + /* Try to reconnect while sending the CDB. */
> + for (attempts = 0; attempts < PR_MAX_RECONNECT_ATTEMPTS; attempts++) {
> + if (!pr_mgr->ioc) {
> + if (pr_manager_helper_initialize(pr_mgr, NULL) < 0) {
> + qemu_mutex_unlock(&pr_mgr->lock);
> + g_usleep(G_USEC_PER_SEC);
> + qemu_mutex_lock(&pr_mgr->lock);
> + }
> + }
> +
> + if (pr_mgr->ioc) {
> + if (pr_manager_helper_write(pr_mgr, fd, cdb,
> + ARRAY_SIZE(cdb), NULL) >= 0) {
> + break;
> + }
> + }
> + }
> + if (attempts == PR_MAX_RECONNECT_ATTEMPTS) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + /* After sending the CDB, any communications failure causes the
> + * command to fail. The failure is transient, retrying the command
> + * will invoke pr_manager_helper_initialize again.
> + */
> + if (expected_dir == SG_DXFER_TO_DEV) {
> + if (pr_manager_helper_write(pr_mgr, -1, io_hdr->dxferp,
> + len, NULL) < 0) {
> + ret = -EINVAL;
> + goto out;
> + }
> + }
> + if (pr_manager_helper_read(pr_mgr, &resp, sizeof(resp), NULL) < 0) {
> + ret = -EINVAL;
> + goto out;
> + }
> + if (expected_dir == SG_DXFER_FROM_DEV && resp.result == 0) {
> + if (pr_manager_helper_read(pr_mgr, io_hdr->dxferp, len, NULL) < 0) {
> + ret = -EINVAL;
> + goto out;
> + }
> + }
Same for these three errors, too.
> +
> + io_hdr->status = resp.result;
> + if (resp.result == CHECK_CONDITION) {
> + io_hdr->driver_status = SG_ERR_DRIVER_SENSE;
> + io_hdr->sb_len_wr = MIN(io_hdr->mx_sb_len, PR_HELPER_SENSE_SIZE);
> + memcpy(io_hdr->sbp, resp.sense, io_hdr->sb_len_wr);
> + }
> +
> +out:
> + if (ret < 0) {
> + int sense_len = scsi_build_sense(io_hdr->sbp,
> + SENSE_CODE(LUN_COMM_FAILURE));
> + io_hdr->driver_status = SG_ERR_DRIVER_SENSE;
> + io_hdr->sb_len_wr = MIN(io_hdr->mx_sb_len, sense_len);
> + io_hdr->status = CHECK_CONDITION;
> + }
> + qemu_mutex_unlock(&pr_mgr->lock);
> + return ret;
> +}
Fam
- [Qemu-block] [RFC PATCH 00/10] scsi, block: introduce persistent reservation managers, Paolo Bonzini, 2017/08/22
- [Qemu-block] [PATCH 06/10] scsi, file-posix: add support for persistent reservation management, Paolo Bonzini, 2017/08/22
- Re: [Qemu-block] [PATCH 06/10] scsi, file-posix: add support for persistent reservation management, Fam Zheng, 2017/08/23
- Re: [Qemu-block] [Qemu-devel] [PATCH 06/10] scsi, file-posix: add support for persistent reservation management, Eric Blake, 2017/08/24
- Re: [Qemu-block] [Qemu-devel] [PATCH 06/10] scsi, file-posix: add support for persistent reservation management, Daniel P. Berrange, 2017/08/30
- Re: [Qemu-block] [PATCH 06/10] scsi, file-posix: add support for persistent reservation management, Stefan Hajnoczi, 2017/08/30
- [Qemu-block] [PATCH 10/10] scsi: add persistent reservation manager using qemu-pr-helper, Paolo Bonzini, 2017/08/22
- [Qemu-block] [PATCH 07/10] io: add qio_channel_read/write_all, Paolo Bonzini, 2017/08/22
- [Qemu-block] [PATCH 09/10] scsi: add multipath support to qemu-pr-helper, Paolo Bonzini, 2017/08/22