[dm-devel] [PATCH 2/5] libmultipath: add eh_deadline multipath.conf parameter
Martin Wilck
martin.wilck at suse.com
Fri Oct 30 21:00:48 UTC 2020
On Fri, 2020-10-23 at 16:15 -0500, Benjamin Marzinski wrote:
> There are times a fc rport is never lost, meaning that
> fast_io_fail_tmo
> and dev_loss_tmo never trigger, but scsi commands still hang. This
> can
> cause problems in cases where users have string timing requirements,
Did you mean "strict" here?
> and
> the easiest way to solve these issues is to set eh_deadline. Since
> it's
> already possible to set fast_io_fail_tmo and dev_loss_tmo from
> multipath.conf, and have multipath take care of setting it correctly
> for
> the scsi devices in sysfs, it makes sense to allow users to set
> eh_deadline here as well.
>
> Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
> ---
> libmultipath/config.c | 2 ++
> libmultipath/config.h | 2 ++
> libmultipath/configure.c | 1 +
> libmultipath/dict.c | 10 ++++++
> libmultipath/discovery.c | 70 ++++++++++++++++++++++++++++++----
> ----
> libmultipath/propsel.c | 17 +++++++++
> libmultipath/propsel.h | 1 +
> libmultipath/structs.h | 7 ++++
> multipath/multipath.conf.5 | 16 +++++++++
> 9 files changed, 111 insertions(+), 15 deletions(-)
>
> diff --git a/libmultipath/config.c b/libmultipath/config.c
> index 49e7fb81..9f3cb38d 100644
> --- a/libmultipath/config.c
> +++ b/libmultipath/config.c
> @@ -424,6 +424,7 @@ merge_hwe (struct hwentry * dst, struct hwentry *
> src)
> merge_num(flush_on_last_del);
> merge_num(fast_io_fail);
> merge_num(dev_loss);
> + merge_num(eh_deadline);
> merge_num(user_friendly_names);
> merge_num(retain_hwhandler);
> merge_num(detect_prio);
> @@ -579,6 +580,7 @@ store_hwe (vector hwtable, struct hwentry * dhwe)
> hwe->flush_on_last_del = dhwe->flush_on_last_del;
> hwe->fast_io_fail = dhwe->fast_io_fail;
> hwe->dev_loss = dhwe->dev_loss;
> + hwe->eh_deadline = dhwe->eh_deadline;
> hwe->user_friendly_names = dhwe->user_friendly_names;
> hwe->retain_hwhandler = dhwe->retain_hwhandler;
> hwe->detect_prio = dhwe->detect_prio;
> diff --git a/libmultipath/config.h b/libmultipath/config.h
> index 661dd586..9ce37f16 100644
> --- a/libmultipath/config.h
> +++ b/libmultipath/config.h
> @@ -63,6 +63,7 @@ struct hwentry {
> int flush_on_last_del;
> int fast_io_fail;
> unsigned int dev_loss;
> + int eh_deadline;
> int user_friendly_names;
> int retain_hwhandler;
> int detect_prio;
> @@ -148,6 +149,7 @@ struct config {
> int attribute_flags;
> int fast_io_fail;
> unsigned int dev_loss;
> + int eh_deadline;
> int log_checker_err;
> int allow_queueing;
> int allow_usb_devices;
> diff --git a/libmultipath/configure.c b/libmultipath/configure.c
> index 1c8aac08..a878d870 100644
> --- a/libmultipath/configure.c
> +++ b/libmultipath/configure.c
> @@ -368,6 +368,7 @@ int setup_map(struct multipath *mpp, char
> *params, int params_size,
> select_gid(conf, mpp);
> select_fast_io_fail(conf, mpp);
> select_dev_loss(conf, mpp);
> + select_eh_deadline(conf, mpp);
> select_reservation_key(conf, mpp);
> select_deferred_remove(conf, mpp);
> select_marginal_path_err_sample_time(conf, mpp);
> diff --git a/libmultipath/dict.c b/libmultipath/dict.c
> index f4357da1..bab96146 100644
> --- a/libmultipath/dict.c
> +++ b/libmultipath/dict.c
> @@ -899,6 +899,13 @@ declare_ovr_snprint(dev_loss, print_dev_loss)
> declare_hw_handler(dev_loss, set_dev_loss)
> declare_hw_snprint(dev_loss, print_dev_loss)
>
> +declare_def_handler(eh_deadline, set_undef_off_zero)
> +declare_def_snprint(eh_deadline, print_undef_off_zero)
> +declare_ovr_handler(eh_deadline, set_undef_off_zero)
> +declare_ovr_snprint(eh_deadline, print_undef_off_zero)
> +declare_hw_handler(eh_deadline, set_undef_off_zero)
> +declare_hw_snprint(eh_deadline, print_undef_off_zero)
> +
> static int
> set_pgpolicy(vector strvec, void *ptr)
> {
> @@ -1771,6 +1778,7 @@ init_keywords(vector keywords)
> install_keyword("gid", &def_gid_handler, &snprint_def_gid);
> install_keyword("fast_io_fail_tmo", &def_fast_io_fail_handler,
> &snprint_def_fast_io_fail);
> install_keyword("dev_loss_tmo", &def_dev_loss_handler,
> &snprint_def_dev_loss);
> + install_keyword("eh_deadline", &def_eh_deadline_handler,
> &snprint_def_eh_deadline);
> install_keyword("bindings_file", &def_bindings_file_handler,
> &snprint_def_bindings_file);
> install_keyword("wwids_file", &def_wwids_file_handler,
> &snprint_def_wwids_file);
> install_keyword("prkeys_file", &def_prkeys_file_handler,
> &snprint_def_prkeys_file);
> @@ -1880,6 +1888,7 @@ init_keywords(vector keywords)
> install_keyword("flush_on_last_del",
> &hw_flush_on_last_del_handler, &snprint_hw_flush_on_last_del);
> install_keyword("fast_io_fail_tmo", &hw_fast_io_fail_handler,
> &snprint_hw_fast_io_fail);
> install_keyword("dev_loss_tmo", &hw_dev_loss_handler,
> &snprint_hw_dev_loss);
> + install_keyword("eh_deadline", &hw_eh_deadline_handler,
> &snprint_hw_eh_deadline);
> install_keyword("user_friendly_names",
> &hw_user_friendly_names_handler, &snprint_hw_user_friendly_names);
> install_keyword("retain_attached_hw_handler",
> &hw_retain_hwhandler_handler, &snprint_hw_retain_hwhandler);
> install_keyword("detect_prio", &hw_detect_prio_handler,
> &snprint_hw_detect_prio);
> @@ -1920,6 +1929,7 @@ init_keywords(vector keywords)
> install_keyword("flush_on_last_del",
> &ovr_flush_on_last_del_handler, &snprint_ovr_flush_on_last_del);
> install_keyword("fast_io_fail_tmo", &ovr_fast_io_fail_handler,
> &snprint_ovr_fast_io_fail);
> install_keyword("dev_loss_tmo", &ovr_dev_loss_handler,
> &snprint_ovr_dev_loss);
> + install_keyword("eh_deadline", &ovr_eh_deadline_handler,
> &snprint_ovr_eh_deadline);
> install_keyword("user_friendly_names",
> &ovr_user_friendly_names_handler, &snprint_ovr_user_friendly_names);
> install_keyword("retain_attached_hw_handler",
> &ovr_retain_hwhandler_handler, &snprint_ovr_retain_hwhandler);
> install_keyword("detect_prio", &ovr_detect_prio_handler,
> &snprint_ovr_detect_prio);
> diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
> index 950b1586..ef9a9a23 100644
> --- a/libmultipath/discovery.c
> +++ b/libmultipath/discovery.c
> @@ -585,6 +585,42 @@ sysfs_get_asymmetric_access_state(struct path
> *pp, char *buff, int buflen)
> return !!preferred;
> }
>
> +static int
> +sysfs_set_eh_deadline(struct multipath *mpp, struct path *pp)
> +{
> + struct udev_device *hostdev;
> + char host_name[HOST_NAME_LEN], value[16];
> + int ret;
> +
> + if (mpp->eh_deadline == EH_DEADLINE_UNSET)
> + return 0;
> +
> + sprintf(host_name, "host%d", pp->sg_id.host_no);
> + hostdev = udev_device_new_from_subsystem_sysname(udev,
> + "scsi_host", host_name);
> + if (!hostdev)
> + return 1;
> +
> + if (mpp->eh_deadline == EH_DEADLINE_OFF)
> + sprintf(value, "off");
> + else if (mpp->eh_deadline == EH_DEADLINE_ZERO)
> + sprintf(value, "0");
> + else
> + snprintf(value, 16, "%u", mpp->eh_deadline);
Hm, mpp->eh_deadline is an "int". This should cause a compiler warning,
does it not?
Nitpick: You're certain to not need more than 11 bytes of string
buffer, so you could simply use sprintf(). If you want to use
snprintf(), please pass sizeof(value) rather than an explicit number.
> +
> + ret = sysfs_attr_set_value(hostdev, "eh_deadline",
> + value, strlen(value));
Nitpick: you could use the return value of sprintf() here rather than
calling strlen() again.
> + /*
> + * not all scsi drivers support setting eh_deadline, so failing
> + * is totally reasonable
> + */
> + if (ret <= 0)
> + condlog(4, "%s: failed to set eh_deadline to %s, error
> %d", udev_device_get_sysname(hostdev), value, -ret);
Loglevel 3 might still be justified. After all, the user did set
eh_deadline, and might wonder why her settings aren't applied.
> +
> + udev_device_unref(hostdev);
> + return (ret <= 0);
> +}
> +
> static void
> sysfs_set_rport_tmo(struct multipath *mpp, struct path *pp)
> {
> @@ -799,7 +835,8 @@ sysfs_set_scsi_tmo (struct multipath *mpp,
> unsigned int checkint)
> mpp->fast_io_fail = MP_FAST_IO_FAIL_OFF;
> }
> if (mpp->dev_loss == DEV_LOSS_TMO_UNSET &&
> - mpp->fast_io_fail == MP_FAST_IO_FAIL_UNSET)
> + mpp->fast_io_fail == MP_FAST_IO_FAIL_UNSET &&
> + mpp->eh_deadline == EH_DEADLINE_UNSET)
> return 0;
>
> vector_foreach_slot(mpp->paths, pp, i) {
> @@ -808,21 +845,24 @@ sysfs_set_scsi_tmo (struct multipath *mpp,
> unsigned int checkint)
> err_path = pp;
> continue;
> }
> -
> - switch (pp->sg_id.proto_id) {
> - case SCSI_PROTOCOL_FCP:
> - sysfs_set_rport_tmo(mpp, pp);
> - continue;
> - case SCSI_PROTOCOL_ISCSI:
> - sysfs_set_session_tmo(mpp, pp);
> - continue;
> - case SCSI_PROTOCOL_SAS:
> - sysfs_set_nexus_loss_tmo(mpp, pp);
> - continue;
> - default:
> - if (!err_path)
> - err_path = pp;
> + if (mpp->dev_loss != DEV_LOSS_TMO_UNSET ||
> + mpp->fast_io_fail != MP_FAST_IO_FAIL_UNSET) {
Perhaps we should rather check these in the called functions then
introduce another conditional here. Some callees do check these
already. We've got the likely shortcut (none set) above already.
> + switch (pp->sg_id.proto_id) {
> + case SCSI_PROTOCOL_FCP:
> + sysfs_set_rport_tmo(mpp, pp);
> + break;
> + case SCSI_PROTOCOL_ISCSI:
> + sysfs_set_session_tmo(mpp, pp);
> + break;
> + case SCSI_PROTOCOL_SAS:
> + sysfs_set_nexus_loss_tmo(mpp, pp);
> + break;
> + default:
> + if (!err_path)
> + err_path = pp;
> + }
> }
> + sysfs_set_eh_deadline(mpp, pp);
> }
>
> if (err_path) {
> diff --git a/libmultipath/propsel.c b/libmultipath/propsel.c
> index 67d025cf..fa4ac5d9 100644
> --- a/libmultipath/propsel.c
> +++ b/libmultipath/propsel.c
> @@ -775,6 +775,23 @@ out:
> return 0;
> }
>
> +int select_eh_deadline(struct config *conf, struct multipath *mp)
> +{
> + const char *origin;
> + char buff[12];
> +
> + mp_set_ovr(eh_deadline);
> + mp_set_hwe(eh_deadline);
> + mp_set_conf(eh_deadline);
> + mp->eh_deadline = EH_DEADLINE_UNSET;
> + /* not changing sysfs in default cause, so don't print anything
> */
> + return 0;
> +out:
> + print_undef_off_zero(buff, 12, mp->eh_deadline);
> + condlog(3, "%s: eh_deadline = %s %s", mp->alias, buff, origin);
> + return 0;
> +}
> +
> int select_flush_on_last_del(struct config *conf, struct multipath
> *mp)
> {
> const char *origin;
> diff --git a/libmultipath/propsel.h b/libmultipath/propsel.h
> index 3d6edd8a..a68bacf0 100644
> --- a/libmultipath/propsel.h
> +++ b/libmultipath/propsel.h
> @@ -17,6 +17,7 @@ int select_uid(struct config *conf, struct
> multipath *mp);
> int select_gid(struct config *conf, struct multipath *mp);
> int select_fast_io_fail(struct config *conf, struct multipath *mp);
> int select_dev_loss(struct config *conf, struct multipath *mp);
> +int select_eh_deadline(struct config *conf, struct multipath *mp);
> int select_reservation_key(struct config *conf, struct multipath
> *mp);
> int select_retain_hwhandler (struct config *conf, struct multipath *
> mp);
> int select_detect_prio(struct config *conf, struct path * pp);
> diff --git a/libmultipath/structs.h b/libmultipath/structs.h
> index cfa7b649..d6ff6762 100644
> --- a/libmultipath/structs.h
> +++ b/libmultipath/structs.h
> @@ -236,6 +236,12 @@ enum fast_io_fail_states {
> MP_FAST_IO_FAIL_ZERO = UOZ_ZERO,
> };
>
> +enum eh_deadline_states {
> + EH_DEADLINE_UNSET = UOZ_UNDEF,
> + EH_DEADLINE_OFF = UOZ_OFF,
> + EH_DEADLINE_ZERO = UOZ_ZERO,
> +};
> +
> struct vpd_vendor_page {
> int pg;
> const char *name;
> @@ -356,6 +362,7 @@ struct multipath {
> int ghost_delay;
> int ghost_delay_tick;
> unsigned int dev_loss;
> + int eh_deadline;
> uid_t uid;
> gid_t gid;
> mode_t mode;
> diff --git a/multipath/multipath.conf.5 b/multipath/multipath.conf.5
> index d2101ed6..cf05c1ab 100644
> --- a/multipath/multipath.conf.5
> +++ b/multipath/multipath.conf.5
> @@ -717,6 +717,22 @@ The default is: \fB600\fR
> .
> .
> .TP
> +.B eh_deadline
> +Specify the maximum number of seconds the SCSI layer will spend
> doing error
> +handling when scsi devices fail. After this timeout the scsi layer
> will perform
> +a full HBA reset. Setting this may be necessary in cases where the
> rport is
> +never lost, so \fIfast_io_fail_tmo\fR and \fIdev_loss_tmo\fR will
> never
> +trigger, but (frequently do to load) scsi commands still hang.
> \fBNote:\fR when
> +the scsi error handler performs the HBA reset, all target paths on
> that HBA
> +will be affected. eh_deadline should only be set in cases where all
> targets on
> +the affected HBAs are multipathed.
> +.RS
> +.TP
> +The default is: \fB<unset>\fR
> +.RE
> +.
> +.
> +.TP
> .B bindings_file
> The full pathname of the binding file to be used when the
> user_friendly_names
> option is set.
--
Dr. Martin Wilck <mwilck at suse.com>, Tel. +49 (0)911 74053 2107
SUSE Software Solutions Germany GmbH
HRB 36809, AG Nürnberg GF: Felix
Imendörffer
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