On Thu, Nov 13, 2025 at 10:43:17AM -0800, Brian Bunker wrote: > In the Linux kernel when volumes are disconnected, they are left behind > to be re-enabled when the connection comes back. There are many cases > where this behavior is not desirable. > > The goal is to have paths appear when volumes are connected. This is > handled by target initiated rescans and posting of unit attentions. > Secondarily when volumes are disconnected at the target, paths should > be removed. > > This was discussed here in a kernel patch: > https://marc.info/?l=linux-scsi&m=164426722617834&w=2 > > It was suggested there that userspace would be more advantageous in > handling the device removal. > > An option was added to multipath-tools to purge devices that are > disconnected at the target. A purge thread was implemented to handle > the device removal when the path returns sense data (0x5/0x25/0x0) from > the path checker. The option, purge_disconnected, is by default off but > can be turned on by setting it to true. > > When enabled multipathd will log: > Nov 11 18:43:24 init539-33 multipathd[52046]: sdc: mark (disconnected) > path for purge > ... > Nov 13 09:54:17 init539-33 multipathd[69140]: purged 8 paths, 0 failed, > 0 pending in 0.125017 secs
I think this is an o.k. idea. I think that the most common case I see of a device getting disconnected while multipathed, is when someone is reamapping the LUN. They could just be growing the LUN, in which case removing the path isn't great. But far too often, users are remapping the LUN to completely different storage. However, if recheck_wwid is set, multipathd will catch this when the path is restored. So, my only reservation with adding this, is that recheck_wwid should solve the problematic issue (LUNs getting remapped to completely different storage) just as well, while not removing paths from devices that are just growing the LUN (assuming that doesn't cause the array to change the LUN's wwid). On the other hand, it's an optional parameter, and it will cause the path to disappear much sooner than recheck_wwid will, so overall, I fine with adding it. I do have some specific issues with the patch below. > Signed-off-by: Brian Bunker <[email protected]> > Signed-off-by: Krishna Kant <[email protected]> > --- > libmultipath/checkers.c | 2 + > libmultipath/checkers.h | 2 + > libmultipath/checkers/tur.c | 12 ++ > libmultipath/config.c | 2 + > libmultipath/config.h | 3 + > libmultipath/configure.c | 1 + > libmultipath/defaults.h | 1 + > libmultipath/dict.c | 14 +++ > libmultipath/io_err_stat.c | 1 + > libmultipath/print.c | 2 + > libmultipath/propsel.c | 16 +++ > libmultipath/propsel.h | 1 + > libmultipath/structs.h | 9 ++ > multipath/multipath.conf.5.in | 21 ++++ > multipathd/main.c | 229 +++++++++++++++++++++++++++++++++- > 15 files changed, 310 insertions(+), 6 deletions(-) > > diff --git a/libmultipath/checkers.c b/libmultipath/checkers.c > index e2eda58d..bb6ad1ee 100644 > --- a/libmultipath/checkers.c > +++ b/libmultipath/checkers.c > @@ -43,6 +43,7 @@ static const char *checker_state_names[PATH_MAX_STATE] = { > [PATH_TIMEOUT] = "timeout", > [PATH_REMOVED] = "removed", > [PATH_DELAYED] = "delayed", > + [PATH_DISCONNECTED] = "disconnected", > }; > > static LIST_HEAD(checkers); > @@ -363,6 +364,7 @@ static const char > *generic_msg[CHECKER_GENERIC_MSGTABLE_SIZE] = { > [CHECKER_MSGID_DOWN] = " reports path is down", > [CHECKER_MSGID_GHOST] = " reports path is ghost", > [CHECKER_MSGID_UNSUPPORTED] = " doesn't support this device", > + [CHECKER_MSGID_DISCONNECTED] = " no access to this device", > }; > > const char *checker_message(const struct checker *c) > diff --git a/libmultipath/checkers.h b/libmultipath/checkers.h > index da91f499..903c3ebe 100644 > --- a/libmultipath/checkers.h > +++ b/libmultipath/checkers.h > @@ -78,6 +78,7 @@ enum path_check_state { > PATH_TIMEOUT, > PATH_REMOVED, > PATH_DELAYED, > + PATH_DISCONNECTED, > PATH_MAX_STATE > }; > > @@ -113,6 +114,7 @@ enum { > CHECKER_MSGID_DOWN, > CHECKER_MSGID_GHOST, > CHECKER_MSGID_UNSUPPORTED, > + CHECKER_MSGID_DISCONNECTED, > CHECKER_GENERIC_MSGTABLE_SIZE, > CHECKER_FIRST_MSGID = 100, /* lowest msgid for checkers */ > CHECKER_MSGTABLE_SIZE = 100, /* max msg table size for checkers */ > diff --git a/libmultipath/checkers/tur.c b/libmultipath/checkers/tur.c > index 0010acf8..1bf2ca97 100644 > --- a/libmultipath/checkers/tur.c > +++ b/libmultipath/checkers/tur.c > @@ -34,6 +34,7 @@ enum { > MSG_TUR_TIMEOUT, > MSG_TUR_FAILED, > MSG_TUR_TRANSITIONING, > + MSG_TUR_DISCONNECTED, > }; > you already added a generic message for the PATH_DISCONNECTED state, so we don't need a TUR checker specific one as well. > #define IDX_(x) (MSG_ ## x - CHECKER_FIRST_MSGID) > @@ -42,6 +43,7 @@ const char *libcheck_msgtable[] = { > [IDX_(TUR_TIMEOUT)] = " timed out", > [IDX_(TUR_FAILED)] = " failed to initialize", > [IDX_(TUR_TRANSITIONING)] = " reports path is transitioning", > + [IDX_(TUR_DISCONNECTED)] = " no access to this device", > NULL, > }; > > @@ -199,6 +201,16 @@ retry: > return PATH_PENDING; > } > } > + else if (key == 0x5) { > + /* Illegal request */ > + if (asc == 0x25 && ascq == 0x00) { > + /* > + * LOGICAL UNIT NOT SUPPORTED > + */ > + *msgid = MSG_TUR_DISCONNECTED; This should just used CHECKER_MSGID_DISCONNECTED > + return PATH_DISCONNECTED; > + } > + } > *msgid = CHECKER_MSGID_DOWN; > return PATH_DOWN; > } > diff --git a/libmultipath/config.c b/libmultipath/config.c > index 8b424d18..2c66a788 100644 > --- a/libmultipath/config.c > +++ b/libmultipath/config.c > @@ -470,6 +470,7 @@ merge_hwe (struct hwentry * dst, struct hwentry * src) > merge_num(marginal_path_err_rate_threshold); > merge_num(marginal_path_err_recheck_gap_time); > merge_num(marginal_path_double_failed_time); > + merge_num(purge_disconnected); > > snprintf(id, sizeof(id), "%s/%s", dst->vendor, dst->product); > reconcile_features_with_options(id, &dst->features, > @@ -517,6 +518,7 @@ merge_mpe(struct mpentry *dst, struct mpentry *src) > merge_num(skip_kpartx); > merge_num(max_sectors_kb); > merge_num(ghost_delay); > + merge_num(purge_disconnected); I can definitely see the reason why you might want to set this option on a per-array-type basis. Not all scsi arrays return the status you would expect. I'm not sure that setting this on a per-multipath-device basis makes much sense. Maybe you have a good reason for doing this? I realize that some of the other options in the multipaths section don't make tons of sense to set per-multipath-device, so possibly you just thought that doing this was necessary. > merge_num(uid); > merge_num(gid); > merge_num(mode); > diff --git a/libmultipath/config.h b/libmultipath/config.h > index 5b4ebf8c..618fa572 100644 > --- a/libmultipath/config.h > +++ b/libmultipath/config.h > @@ -88,6 +88,7 @@ struct hwentry { > int marginal_path_err_rate_threshold; > int marginal_path_err_recheck_gap_time; > int marginal_path_double_failed_time; > + int purge_disconnected; > int skip_kpartx; > int max_sectors_kb; > int ghost_delay; > @@ -130,6 +131,7 @@ struct mpentry { > int marginal_path_err_rate_threshold; > int marginal_path_err_recheck_gap_time; > int marginal_path_double_failed_time; > + int purge_disconnected; same issue as above. > int skip_kpartx; > int max_sectors_kb; > int ghost_delay; > @@ -188,6 +190,7 @@ struct config { > int marginal_path_err_rate_threshold; > int marginal_path_err_recheck_gap_time; > int marginal_path_double_failed_time; > + int purge_disconnected; > int uxsock_timeout; > int strict_timing; > int retrigger_tries; > diff --git a/libmultipath/configure.c b/libmultipath/configure.c > index baa13573..e4431d2f 100644 > --- a/libmultipath/configure.c > +++ b/libmultipath/configure.c > @@ -355,6 +355,7 @@ int setup_map(struct multipath *mpp, char **params, > struct vectors *vecs) > select_max_sectors_kb(conf, mpp); > select_ghost_delay(conf, mpp); > select_flush_on_last_del(conf, mpp); > + select_purge_disconnected(conf, mpp); > > sysfs_set_scsi_tmo(conf, mpp); > marginal_pathgroups = conf->marginal_pathgroups; > diff --git a/libmultipath/defaults.h b/libmultipath/defaults.h > index 134b690a..d80dd7d4 100644 > --- a/libmultipath/defaults.h > +++ b/libmultipath/defaults.h > @@ -58,6 +58,7 @@ > #define DEFAULT_ALL_TG_PT ALL_TG_PT_OFF > #define DEFAULT_RECHECK_WWID RECHECK_WWID_OFF > #define DEFAULT_AUTO_RESIZE AUTO_RESIZE_NEVER > +#define DEFAULT_PURGE_DISCONNECTED PURGE_DISCONNECTED_OFF > /* Enable no foreign libraries by default */ > #define DEFAULT_ENABLE_FOREIGN "NONE" > > diff --git a/libmultipath/dict.c b/libmultipath/dict.c > index a06a6138..504b28b5 100644 > --- a/libmultipath/dict.c > +++ b/libmultipath/dict.c > @@ -941,6 +941,16 @@ declare_hw_snprint(skip_kpartx, print_yes_no_undef) > declare_mp_handler(skip_kpartx, set_yes_no_undef) > declare_mp_snprint(skip_kpartx, print_yes_no_undef) > > +declare_def_handler(purge_disconnected, set_yes_no_undef) > +declare_def_snprint_defint(purge_disconnected, print_yes_no_undef, > + DEFAULT_PURGE_DISCONNECTED) > +declare_ovr_handler(purge_disconnected, set_yes_no_undef) > +declare_ovr_snprint(purge_disconnected, print_yes_no_undef) > +declare_hw_handler(purge_disconnected, set_yes_no_undef) > +declare_hw_snprint(purge_disconnected, print_yes_no_undef) > +declare_mp_handler(purge_disconnected, set_yes_no_undef) > +declare_mp_snprint(purge_disconnected, print_yes_no_undef) Same issue as above (for the declare_mp_* macros) > + > declare_def_range_handler(remove_retries, 0, INT_MAX) > declare_def_snprint(remove_retries, print_int) > > @@ -2227,6 +2237,7 @@ init_keywords(vector keywords) > install_keyword("retrigger_delay", &def_retrigger_delay_handler, > &snprint_def_retrigger_delay); > install_keyword("missing_uev_wait_timeout", > &def_uev_wait_timeout_handler, &snprint_def_uev_wait_timeout); > install_keyword("skip_kpartx", &def_skip_kpartx_handler, > &snprint_def_skip_kpartx); > + install_keyword("purge_disconnected", &def_purge_disconnected_handler, > &snprint_def_purge_disconnected); > install_keyword("disable_changed_wwids", > &deprecated_disable_changed_wwids_handler, &snprint_deprecated); > install_keyword("remove_retries", &def_remove_retries_handler, > &snprint_def_remove_retries); > install_keyword("max_sectors_kb", &def_max_sectors_kb_handler, > &snprint_def_max_sectors_kb); > @@ -2310,6 +2321,7 @@ init_keywords(vector keywords) > install_keyword("marginal_path_err_recheck_gap_time", > &hw_marginal_path_err_recheck_gap_time_handler, > &snprint_hw_marginal_path_err_recheck_gap_time); > install_keyword("marginal_path_double_failed_time", > &hw_marginal_path_double_failed_time_handler, > &snprint_hw_marginal_path_double_failed_time); > install_keyword("skip_kpartx", &hw_skip_kpartx_handler, > &snprint_hw_skip_kpartx); > + install_keyword("purge_disconnected", &hw_purge_disconnected_handler, > &snprint_hw_purge_disconnected); > install_keyword("max_sectors_kb", &hw_max_sectors_kb_handler, > &snprint_hw_max_sectors_kb); > install_keyword("ghost_delay", &hw_ghost_delay_handler, > &snprint_hw_ghost_delay); > install_keyword("all_tg_pt", &hw_all_tg_pt_handler, > &snprint_hw_all_tg_pt); > @@ -2355,6 +2367,7 @@ init_keywords(vector keywords) > install_keyword("marginal_path_double_failed_time", > &ovr_marginal_path_double_failed_time_handler, > &snprint_ovr_marginal_path_double_failed_time); > > install_keyword("skip_kpartx", &ovr_skip_kpartx_handler, > &snprint_ovr_skip_kpartx); > + install_keyword("purge_disconnected", &ovr_purge_disconnected_handler, > &snprint_ovr_purge_disconnected); > install_keyword("max_sectors_kb", &ovr_max_sectors_kb_handler, > &snprint_ovr_max_sectors_kb); > install_keyword("ghost_delay", &ovr_ghost_delay_handler, > &snprint_ovr_ghost_delay); > install_keyword("all_tg_pt", &ovr_all_tg_pt_handler, > &snprint_ovr_all_tg_pt); > @@ -2400,6 +2413,7 @@ init_keywords(vector keywords) > install_keyword("marginal_path_err_recheck_gap_time", > &mp_marginal_path_err_recheck_gap_time_handler, > &snprint_mp_marginal_path_err_recheck_gap_time); > install_keyword("marginal_path_double_failed_time", > &mp_marginal_path_double_failed_time_handler, > &snprint_mp_marginal_path_double_failed_time); > install_keyword("skip_kpartx", &mp_skip_kpartx_handler, > &snprint_mp_skip_kpartx); > + install_keyword("purge_disconnected", &mp_purge_disconnected_handler, > &snprint_mp_purge_disconnected); same issue as above > install_keyword("max_sectors_kb", &mp_max_sectors_kb_handler, > &snprint_mp_max_sectors_kb); > install_keyword("ghost_delay", &mp_ghost_delay_handler, > &snprint_mp_ghost_delay); > install_sublevel_end(); > diff --git a/libmultipath/io_err_stat.c b/libmultipath/io_err_stat.c > index 64054c18..acb087b7 100644 > --- a/libmultipath/io_err_stat.c > +++ b/libmultipath/io_err_stat.c > @@ -397,6 +397,7 @@ static void account_async_io_state(struct > io_err_stat_path *pp, int rc) > switch (rc) { > case PATH_DOWN: > case PATH_TIMEOUT: > + case PATH_DISCONNECTED: > pp->io_err_nr++; > break; > case PATH_UNCHECKED: > diff --git a/libmultipath/print.c b/libmultipath/print.c > index 0d44a5a9..8b09b174 100644 > --- a/libmultipath/print.c > +++ b/libmultipath/print.c > @@ -541,6 +541,8 @@ snprint_chk_state (struct strbuf *buff, const struct path > * pp) > return append_strbuf_str(buff, "i/o timeout"); > case PATH_DELAYED: > return append_strbuf_str(buff, "delayed"); > + case PATH_DISCONNECTED: > + return append_strbuf_str(buff, "disconnected"); > default: > return append_strbuf_str(buff, "undef"); > } > diff --git a/libmultipath/propsel.c b/libmultipath/propsel.c > index 4c0fbcf3..9a17f1ed 100644 > --- a/libmultipath/propsel.c > +++ b/libmultipath/propsel.c > @@ -1371,6 +1371,22 @@ out: > return 0; > } > > +int select_purge_disconnected (struct config *conf, struct multipath * mp) > +{ > + const char *origin; > + > + mp_set_mpe(purge_disconnected); Same issue as above > + mp_set_ovr(purge_disconnected); > + mp_set_hwe(purge_disconnected); > + mp_set_conf(purge_disconnected); > + mp_set_default(purge_disconnected, DEFAULT_PURGE_DISCONNECTED); > +out: > + condlog(3, "%s: purge_disconnected = %s %s", mp->alias, > + (mp->purge_disconnected == PURGE_DISCONNECTED_ON)? "yes" : "no", > + origin); > + return 0; > +} > + > int select_max_sectors_kb(struct config *conf, struct multipath * mp) > { > const char *origin; > diff --git a/libmultipath/propsel.h b/libmultipath/propsel.h > index 55930050..c6c937c3 100644 > --- a/libmultipath/propsel.h > +++ b/libmultipath/propsel.h > @@ -39,6 +39,7 @@ int select_marginal_path_err_rate_threshold(struct config > *conf, struct multipat > int select_marginal_path_err_recheck_gap_time(struct config *conf, struct > multipath *mp); > int select_marginal_path_double_failed_time(struct config *conf, struct > multipath *mp); > int select_ghost_delay(struct config *conf, struct multipath * mp); > +int select_purge_disconnected (struct config *conf, struct multipath * mp); > void reconcile_features_with_options(const char *id, char **features, > int* no_path_retry, > int *retain_hwhandler); > diff --git a/libmultipath/structs.h b/libmultipath/structs.h > index 9247e74f..bca01f41 100644 > --- a/libmultipath/structs.h > +++ b/libmultipath/structs.h > @@ -186,6 +186,12 @@ enum auto_resize_state { > AUTO_RESIZE_GROW_SHRINK, > }; > > +enum purge_disconnected_states { > + PURGE_DISCONNECTED_UNDEF = YNU_UNDEF, > + PURGE_DISCONNECTED_OFF = YNU_NO, > + PURGE_DISCONNECTED_ON = YNU_YES, > +}; > + > #define PROTOCOL_UNSET -1 > > enum scsi_protocol { > @@ -382,6 +388,8 @@ struct path { > int dmstate; > int chkrstate; > int oldstate; > + bool purge_path; > + int purge_retries; /* number of purge attempts for this path */ > int failcount; > int priority; > int pgindex; > @@ -483,6 +491,7 @@ struct multipath { > int ghost_delay; > int ghost_delay_tick; > int queue_mode; > + int purge_disconnected; > unsigned int sync_tick; > int checker_count; > enum prio_update_type prio_update; > diff --git a/multipath/multipath.conf.5.in b/multipath/multipath.conf.5.in > index 3c9ae097..1f806da8 100644 > --- a/multipath/multipath.conf.5.in > +++ b/multipath/multipath.conf.5.in > @@ -1306,6 +1306,21 @@ The default is: \fBno\fR > . > . > .TP > +.B purge_disconnected > +If set to > +.I yes > +, multipathd will automatically remove paths that are in the disconnected > state > +by writing to the SCSI device's sysfs delete attribute. This triggers > kernel-level > +device removal. Paths are retried multiple times before being forcibly > cleaned up > +if the kernel removal fails. This option is useful for cleaning up stale > paths > +from storage arrays that have been disconnected or removed. > +.RS > +.TP > +The default is: \fBno\fR > +.RE > +. > +. > +.TP > .B disable_changed_wwids > (Deprecated) This option is not supported anymore, and will be ignored. > .RE > @@ -1602,6 +1617,8 @@ section: > .TP > .B skip_kpartx > .TP > +.B purge_disconnected > +.TP same issue as above > .B max_sectors_kb > .TP > .B ghost_delay > @@ -1797,6 +1814,8 @@ section: > .TP > .B skip_kpartx > .TP > +.B purge_disconnected > +.TP > .B max_sectors_kb > .TP > .B ghost_delay > @@ -1881,6 +1900,8 @@ the values are taken from the \fIdevices\fR or > \fIdefaults\fR sections: > .TP > .B skip_kpartx > .TP > +.B purge_disconnected > +.TP > .B max_sectors_kb > .TP > .B ghost_delay > diff --git a/multipathd/main.c b/multipathd/main.c > index d11a8576..a07021c4 100644 > --- a/multipathd/main.c > +++ b/multipathd/main.c > @@ -137,11 +137,14 @@ static enum force_reload_types reconfigure_pending = > FORCE_RELOAD_NONE; I'm not sure that we need a whole new thread for this. Writing to the sysfs file should be something that we can do directly in get_new_state. I get that we might not want to keep writing to the sysfs file every time we check the path (5 seconds by default). How does this sound: In the path struct, store a purge_retry_tick. In get_new_state(), if the state comes back as PATH_DISCONNECTED and purging is enabled, you can use the purge_retry_tick to make sure that you only call delete_path() every 10 checks or so. Even if purging isn't enabled, it might be smart to track when a path returns PATH_DISCONNECTED, and when that path comes back up again, check for a wwid change, even if recheck_wwids isn't set. I'm also not sure we need the code to forceably remove the path. If the path was removed, and we just didn't have a uevent, or it the path stopped being a scsi device (I'm not sure how that works), multipathd already has code to ignore devices with no sysfs entries. It still wouldn't be deleted without the uevent, but we won't keep trying to send it delete messages. And I'm not sure we need to worry about the other case you mentioned, where the sysfs interface doesn't exist. Are there SCSI devices where the delete sysfs attribute doesn't exist? That attribute has been around for a while. Or is there an actual case you ran into, that I'm just overlooking, where the device needed to be forceably deleted. If you'd like, I could write a patch with these changes for you to try out. Otherwise, you're welcome to revise this and repost. I would also like to hear Martin Wilck's opinion on this idea (Cc'ed). For future patches, you should Cc both of us. Thanks. -Ben > pid_t daemon_pid; > static pthread_mutex_t config_lock = PTHREAD_MUTEX_INITIALIZER; > static pthread_cond_t config_cond; > -static pthread_t check_thr, uevent_thr, uxlsnr_thr, uevq_thr, dmevent_thr, > - fpin_thr, fpin_consumer_thr; > -static bool check_thr_started, uevent_thr_started, uxlsnr_thr_started, > - uevq_thr_started, dmevent_thr_started, fpin_thr_started, > - fpin_consumer_thr_started; > +static pthread_mutex_t purge_mutex = PTHREAD_MUTEX_INITIALIZER; > +static pthread_cond_t purge_cond = PTHREAD_COND_INITIALIZER; > +int devices_to_purge = 0; > +static pthread_t check_thr, purge_thr, uevent_thr, uxlsnr_thr, uevq_thr, > + dmevent_thr, fpin_thr, fpin_consumer_thr; > +static bool check_thr_started, purge_thr_started, uevent_thr_started, > + uxlsnr_thr_started, uevq_thr_started, dmevent_thr_started, > + fpin_thr_started, fpin_consumer_thr_started; > static int pid_fd = -1; > > static inline enum daemon_status get_running_state(bool *pending_reconfig) > @@ -1089,6 +1092,34 @@ check_path_wwid_change(struct path *pp) > return false; > } > > +/* > + * Attempt to delete a path by writing to the SCSI device's sysfs delete > attribute. > + * This triggers kernel-level device removal. The actual cleanup of the path > structure > + * from pathvec happens later when a uevent arrives (handled by > uev_remove_path). > + * > + * Returns: > + * true - sysfs write succeeded, uevent expected > + * false - sysfs write failed or device not found > + */ > +static bool > +delete_path(struct path * pp) > +{ > + struct udev_device *ud = > udev_device_get_parent_with_subsystem_devtype(pp->udev, > + "scsi", "scsi_device"); > + > + if (ud) { > + if (sysfs_attr_set_value(ud, "delete", "1", strlen("1")) < 0) { > + condlog(1, "failed to remove path %s from %s", > + pp->dev_t, pp->mpp->alias); > + return false; > + } > + condlog(2, "removed path %s from %s", pp->dev_t, > pp->mpp->alias); > + pp->purge_path = false; > + return true; > + } > + return false; > +} > + > /* > * uev_add_path can call uev_update_path, and uev_update_path can call > * uev_add_path > @@ -2031,6 +2062,10 @@ reinstate_path (struct path * pp) > condlog(0, "%s: reinstate failed", pp->dev_t); > else { > condlog(2, "%s: reinstated", pp->dev_t); > + if (pp->purge_path) { > + pp->purge_path = false; > + pp->purge_retries = 0; > + } > update_queue_mode_add_path(pp->mpp); > } > } > @@ -2474,6 +2509,20 @@ get_new_state(struct path *pp) > if (newstate == PATH_REMOVED) > newstate = PATH_DOWN; > > + /* > + * For PATH_DISOCONNECTED mark the path as OK to purge if that is > + * enabled. Whether or not purge is enabled mark the path as down. > + */ > + if (newstate == PATH_DISCONNECTED) { > + if (pp->mpp->purge_disconnected == PURGE_DISCONNECTED_ON && > + !pp->purge_path) { > + condlog(2, "%s: mark (%s) path for purge", > + pp->dev, checker_state_name(newstate)); > + pp->purge_path = true; > + } > + newstate = PATH_DOWN; If the goal is to treat PATH_DISCONNECTED as PATH_DOWN aside from the purging code, then you need to handle get_state() returning PATH_DISCONNECTED in pathinfo() as well. Probably, it should just set the state to PATH_DOWN, like it does for PATH_TIMEOUT. > + } > + > if (newstate == PATH_WILD || newstate == PATH_UNCHECKED) { > condlog(2, "%s: unusable path (%s) - checker failed", > pp->dev, checker_state_name(newstate)); > @@ -3022,6 +3071,25 @@ update_paths(struct vectors *vecs, int *num_paths_p, > time_t start_secs) > return CHECKER_FINISHED; > } > > +/* > + * Check if there are newly marked paths to purge. > + * Only returns true for paths with purge_path=true and purge_retries=0, > + * which indicates they were just marked for purging and haven't been > + * attempted yet. This prevents signaling the purge thread unnecessarily > + * for paths that are already being retried. > + */ > +static bool > +has_paths_to_purge(struct vectors *vecs) > +{ > + int i; > + struct path *pp; > + > + vector_foreach_slot(vecs->pathvec, pp, i) > + if (pp->purge_path && pp->purge_retries == 0) > + return true; > + return false; > +} > + > static void enable_pathgroups(struct multipath *mpp) > { > struct pathgroup *pgp; > @@ -3125,6 +3193,7 @@ checkerloop (void *ap) > int num_paths = 0, strict_timing; > unsigned int ticks = 0; > enum checker_state checker_state = CHECKER_STARTING; > + bool devs_to_purge = false; > > if (set_config_state(DAEMON_RUNNING) != DAEMON_RUNNING) > /* daemon shutdown */ > @@ -3168,8 +3237,10 @@ checkerloop (void *ap) > if (checker_state == CHECKER_UPDATING_PATHS) > checker_state = update_paths(vecs, &num_paths, > start_time.tv_sec); > - if (checker_state == CHECKER_FINISHED) > + if (checker_state == CHECKER_FINISHED) { > + devs_to_purge = has_paths_to_purge(vecs); > checker_finished(vecs, ticks); > + } > lock_cleanup_pop(vecs->lock); > } > > @@ -3192,6 +3263,13 @@ checkerloop (void *ap) > (long)diff_time.tv_sec); > } > > + if (devs_to_purge) { > + pthread_mutex_lock(&purge_mutex); > + devices_to_purge = 1; > + pthread_cond_signal(&purge_cond); > + pthread_mutex_unlock(&purge_mutex); > + } > + > if (foreign_tick == 0) { > conf = get_multipath_config(); > foreign_tick = conf->max_checkint; > @@ -3229,6 +3307,136 @@ checkerloop (void *ap) > return NULL; > } > > +/* > + * Purge thread: removes disconnected paths by writing to sysfs. > + * > + * This thread is signaled by the checker thread when paths marked with > + * purge_path=true are detected. It attempts to delete these paths by > + * writing "1" to their SCSI device's sysfs "delete" attribute. > + * > + * The actual cleanup of path structures from pathvec happens asynchronously > + * when the kernel sends a remove uevent (handled by uev_remove_path). > + * If the uevent doesn't arrive or the sysfs write fails, paths will be > + * retried on subsequent purge cycles with a timeout mechanism. > + */ > +#define PURGE_TIMEOUT_CYCLES 10 /* ~50 seconds at 5 second check intervals > */ > + > +static void * > +purgeloop (void *ap) > +{ > + struct vectors *vecs; > + struct timespec diff_time, end_time, start_time; > + unsigned int i; > + struct path *pp; > + vecs = (struct vectors *)ap; > + > + pthread_cleanup_push(rcu_unregister, NULL); > + rcu_register_thread(); > + mlockall(MCL_CURRENT | MCL_FUTURE); > + > + while (1) { > + int devices_purged = 0; > + int devices_failed = 0; > + int devices_pending = 0; > + > + pthread_mutex_lock(&purge_mutex); > + while (!devices_to_purge) { > + condlog(3, "waiting on devices to purge"); > + pthread_cond_wait(&purge_cond, &purge_mutex); > + } > + /* Reset flag before releasing mutex to avoid race condition */ > + devices_to_purge = 0; > + pthread_mutex_unlock(&purge_mutex); > + > + condlog(3, "devices available for purge"); > + get_monotonic_time(&start_time); > + pthread_cleanup_push(cleanup_lock, &vecs->lock); > + lock(&vecs->lock); > + pthread_testcancel(); > + > + /* > + * Iterate through all paths and attempt to purge those marked. > + * Use purge_retries as a timeout counter for failed purge > attempts. > + */ > + vector_foreach_slot (vecs->pathvec, pp, i) { > + if (!pp->purge_path) > + continue; > + > + /* Increment timeout counter for this purge attempt */ > + pp->purge_retries++; > + > + if (delete_path(pp)) { > + /* Success: sysfs write succeeded, uevent > expected */ > + devices_purged++; > + pp->purge_retries = 0; > + } else if (pp->purge_retries >= PURGE_TIMEOUT_CYCLES) { > + /* > + * Timeout: path couldn't be deleted after > multiple attempts. > + * This can happen if: > + * - The device is no longer a SCSI device > + * - The sysfs interface is unavailable > + * - The device was already removed but no > uevent arrived > + * > + * Force cleanup by removing from pathvec and > freeing. > + */ > + condlog(1, "%s: purge timeout after %d > attempts, forcing cleanup", > + pp->dev, pp->purge_retries); > + vector_del_slot(vecs->pathvec, i); > + i--; /* Adjust iterator after deletion */ > + free_path(pp); > + devices_failed++; > + } else { > + /* Retry on next purge cycle */ > + devices_pending++; > + } > + } > + > + lock_cleanup_pop(vecs->lock); > + > + diff_time.tv_nsec = 0; > + if (start_time.tv_sec) { > + get_monotonic_time(&end_time); > + timespecsub(&end_time, &start_time, &diff_time); > + if (devices_purged > 0 || devices_failed > 0) { > + condlog(2, "purged %d path%s, %d failed, %d > pending in %ld.%06lu secs", > + devices_purged, devices_purged > 1 ? > "s" : "", > + devices_failed, devices_pending, > + (long)diff_time.tv_sec, > + diff_time.tv_nsec / 1000); > + } > + } > + > + /* > + * If there are still paths pending purge, sleep for the checker > + * cycle interval before retrying. This prevents spinning and > + * ensures the ~5 second retry interval mentioned in > PURGE_TIMEOUT_CYCLES. > + * We sleep outside the mutex to allow the checker thread to > signal > + * us if new paths are marked for purge. > + */ > + if (devices_pending > 0) { > + struct timespec wait_time; > + struct config *conf; > + > + conf = get_multipath_config(); > + wait_time.tv_sec = conf->checkint; > + wait_time.tv_nsec = 0; > + put_multipath_config(conf); > + > + condlog(3, "sleeping %ld seconds before purge retry", > + (long)wait_time.tv_sec); > + nanosleep(&wait_time, NULL); > + > + /* Signal ourselves to process the pending paths */ > + pthread_mutex_lock(&purge_mutex); > + devices_to_purge = 1; > + pthread_mutex_unlock(&purge_mutex); > + } > + } > + > + pthread_cleanup_pop(1); > + return NULL; > +} > + > static int > configure (struct vectors * vecs, enum force_reload_types reload_type) > { > @@ -3669,6 +3877,8 @@ static void cleanup_threads(void) > > if (check_thr_started) > pthread_cancel(check_thr); > + if (purge_thr_started) > + pthread_cancel(purge_thr); > if (uevent_thr_started) > pthread_cancel(uevent_thr); > if (uxlsnr_thr_started) > @@ -3685,6 +3895,8 @@ static void cleanup_threads(void) > > if (check_thr_started) > pthread_join(check_thr, NULL); > + if (purge_thr_started) > + pthread_join(purge_thr, NULL); > if (uevent_thr_started) > pthread_join(uevent_thr, NULL); > if (uxlsnr_thr_started) > @@ -3937,6 +4149,11 @@ child (__attribute__((unused)) void *param) > goto failed; > } else > check_thr_started = true; > + if ((rc = pthread_create(&purge_thr, &misc_attr, purgeloop, vecs))) { > + condlog(0,"failed to create purge loop thread: %d", rc); > + goto failed; > + } else > + purge_thr_started = true; > if ((rc = pthread_create(&uevq_thr, &misc_attr, uevqloop, vecs))) { > condlog(0, "failed to create uevent dispatcher: %d", rc); > goto failed; > -- > 2.51.0 >
