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: Dec 4 16:25:54 init110-14 multipathd[1024]: sdmp: purging disconnected path ... Dec 4 16:25:54 init110-14 multipathd[1024]: /dev/sdmp: triggered removal 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 | 10 ++ libmultipath/config.c | 2 + libmultipath/config.h | 3 + libmultipath/configure.c | 1 + libmultipath/defaults.h | 1 + libmultipath/dict.c | 14 ++ libmultipath/discovery.c | 3 +- libmultipath/io_err_stat.c | 1 + libmultipath/print.c | 2 + libmultipath/propsel.c | 16 ++ libmultipath/propsel.h | 1 + libmultipath/structs.h | 14 ++ libmultipath/sysfs.c | 2 +- multipath/multipath.conf.5.in | 22 +++ multipathd/main.c | 287 +++++++++++++++++++++++++++++++++- 17 files changed, 374 insertions(+), 9 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..1bb9a992 100644 --- a/libmultipath/checkers/tur.c +++ b/libmultipath/checkers/tur.c @@ -199,6 +199,16 @@ retry: return PATH_PENDING; } } + else if (key == 0x5) { + /* Illegal request */ + if (asc == 0x25 && ascq == 0x00) { + /* + * LOGICAL UNIT NOT SUPPORTED + */ + *msgid = 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); 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; 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) + 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); 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/discovery.c b/libmultipath/discovery.c index 31db8758..46274f3f 100644 --- a/libmultipath/discovery.c +++ b/libmultipath/discovery.c @@ -2482,7 +2482,8 @@ int pathinfo(struct path *pp, struct config *conf, int mask) pp->state == PATH_UNCHECKED || pp->state == PATH_WILD) pp->chkrstate = pp->state = newstate; - if (pp->state == PATH_TIMEOUT) + if (pp->state == PATH_TIMEOUT || + pp->state == PATH_DISCONNECTED) pp->state = PATH_DOWN; if (pp->state == PATH_UP && !pp->size) { condlog(3, "%s: device size is 0, " 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); + 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..91397467 100644 --- a/libmultipath/structs.h +++ b/libmultipath/structs.h @@ -186,6 +186,18 @@ 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, +}; + +enum path_disconnected_state { + NOT_DISCONNECTED = 0, + DISCONNECTED_NO_PURGE, + DISCONNECTED_NEEDS_PURGE, +}; + #define PROTOCOL_UNSET -1 enum scsi_protocol { @@ -382,6 +394,7 @@ struct path { int dmstate; int chkrstate; int oldstate; + enum path_disconnected_state disconnected; int failcount; int priority; int pgindex; @@ -483,6 +496,7 @@ 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/libmultipath/sysfs.c b/libmultipath/sysfs.c index af27d107..538800d8 100644 --- a/libmultipath/sysfs.c +++ b/libmultipath/sysfs.c @@ -134,7 +134,7 @@ ssize_t sysfs_attr_set_value(struct udev_device *dev, const char *attr_name, size = write(fd, value, value_len); if (size < 0) { size = -errno; - condlog(3, "%s: write to %s failed: %s", __func__, + condlog(3, "%s: write to %s failed: %s", __func__, devpath, strerror(errno)); } else if (size < (ssize_t)value_len) condlog(3, "%s: underflow writing %zu bytes to %s. Wrote %zd bytes", diff --git a/multipath/multipath.conf.5.in b/multipath/multipath.conf.5.in index 3c9ae097..84cd1a0a 100644 --- a/multipath/multipath.conf.5.in +++ b/multipath/multipath.conf.5.in @@ -1306,6 +1306,22 @@ The default is: \fBno\fR . . .TP +.B purge_disconnected +If set to +.I yes +, multipathd will automatically remove devices that are in a disconnected state. +A path is considered disconnected when the TUR (Test Unit Ready) path checker +receives the SCSI sense code "LOGICAL UNIT NOT SUPPORTED" (sense key 0x5, +ASC/ASCQ 0x25/0x00). This typically indicates that the LUN has been unmapped +or is no longer presented by the storage array. This option helps clean up +stale device entries that would otherwise remain in the system. +.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 +1618,8 @@ section: .TP .B skip_kpartx .TP +.B purge_disconnected +.TP .B max_sectors_kb .TP .B ghost_delay @@ -1797,6 +1815,8 @@ section: .TP .B skip_kpartx .TP +.B purge_disconnected +.TP .B max_sectors_kb .TP .B ghost_delay @@ -1881,6 +1901,8 @@ 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..83754cd9 100644 --- a/multipathd/main.c +++ b/multipathd/main.c @@ -137,11 +137,14 @@ static enum force_reload_types reconfigure_pending = FORCE_RELOAD_NONE; 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 +1092,109 @@ check_path_wwid_change(struct path *pp) return false; } +/* + * Information needed to delete a path via sysfs, copied while holding + * the lock so that the actual sysfs write can be done without holding + * vecs->lock. + * + * The duplicated fd prevents the kernel from reusing the device + * name/H:C:T:L even if the device is removed and a new one appears. + */ +struct purge_path_info { + struct udev_device *udev; /* Reference to udev device (refcounted) */ + int fd; /* Duplicated fd to prevent device reuse */ +}; + +/* + * 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). + * + * This function does NOT require vecs->lock to be held, as it operates on + * copied data. This function may block while writing to sysfs, which is + * why it's called without holding any locks. + */ +static void +delete_path_sysfs(struct purge_path_info *info) +{ + struct udev_device *ud; + const char *devname; + + if (!info->udev) + return; + + devname = udev_device_get_devnode(info->udev); + ud = udev_device_get_parent_with_subsystem_devtype(info->udev, + "scsi", "scsi_device"); + + if (!ud) { + condlog(3, "%s: failed to purge, no SCSI parent device found", + devname); + return; + } + + if (sysfs_attr_set_value(ud, "delete", "1", strlen("1")) < 0) + condlog(3, "%s: failed to purge", devname); + else + condlog(2, "%s: purged", devname); +} + +/* + * Prepare purge info for a path while holding vecs->lock. + * Takes a reference on the udev device and duplicates the fd if + * available. The duplicated fd prevents the kernel from reusing the + * device, but if we can't get one (device already disconnected), we + * proceed anyway since reuse is unlikely in that case. + * Returns true if info was successfully prepared, false otherwise. + */ +static bool +prepare_purge_path_info(struct path *pp, struct purge_path_info *info) +{ + if (!pp->udev || !pp->mpp) + return false; + + info->udev = udev_device_ref(pp->udev); + if (!info->udev) + return false; + + /* + * Try to dup the fd if available, but don't fail if we can't get + * one because the device is already disconnected. + */ + if (pp->fd >= 0) { + info->fd = dup(pp->fd); + if (info->fd < 0) { + condlog(3, "%s: failed to dup fd: %s", pp->dev, + strerror(errno)); + udev_device_unref(info->udev); + info->udev = NULL; + return false; + } + } + + return true; +} + +/* + * Clean up purge info after use. + * This must be usable as a pthread cleanup handler. + */ +static void +cleanup_purge_path_info(void *arg) +{ + struct purge_path_info *info = arg; + + if (info->fd >= 0) { + close(info->fd); + info->fd = -1; + } + if (info->udev) { + udev_device_unref(info->udev); + info->udev = NULL; + } +} + /* * uev_add_path can call uev_update_path, and uev_update_path can call * uev_add_path @@ -2474,6 +2580,21 @@ get_new_state(struct path *pp) if (newstate == PATH_REMOVED) newstate = PATH_DOWN; + /* + * For PATH_DISCONNECTED, mark the path for purging if that feature + * 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->disconnected != DISCONNECTED_NEEDS_PURGE) { + condlog(2, "%s: mark (%s) path for purge", + pp->dev, checker_state_name(newstate)); + pp->disconnected = DISCONNECTED_NEEDS_PURGE; + } + newstate = PATH_DOWN; + } + if (newstate == PATH_WILD || newstate == PATH_UNCHECKED) { condlog(2, "%s: unusable path (%s) - checker failed", pp->dev, checker_state_name(newstate)); @@ -2545,7 +2666,18 @@ update_path_state (struct vectors * vecs, struct path * pp) pp->tick = 1; return CHECK_PATH_SKIPPED; } - if (pp->recheck_wwid == RECHECK_WWID_ON && + + /* + * Recheck WWID if either: + * 1. recheck_wwid is explicitly enabled, OR + * 2. Path was previously disconnected (higher chance of change) + * + * This ensures we catch WWID changes even if users don't enable + * recheck_wwid, since disconnected paths are far more likely to + * have been replaced or reconfigured. + */ + if ((pp->recheck_wwid == RECHECK_WWID_ON || + (pp->disconnected != NOT_DISCONNECTED && can_recheck_wwid(pp))) && (newstate == PATH_UP || newstate == PATH_GHOST) && ((pp->state != PATH_UP && pp->state != PATH_GHOST) || pp->dmstate == PSTATE_FAILED) && @@ -2554,6 +2686,19 @@ update_path_state (struct vectors * vecs, struct path * pp) return handle_path_wwid_change(pp, vecs)? CHECK_PATH_REMOVED : CHECK_PATH_SKIPPED; } + + /* + * If path was previously disconnected and has now recovered to + * UP or GHOST, clear the disconnected state. This happens after + * the WWID recheck above, so we only clear it if the WWID is + * OK. + */ + if (pp->disconnected != NOT_DISCONNECTED && + (newstate == PATH_UP || newstate == PATH_GHOST)) { + condlog(2, "%s: path recovered from disconnected state", + pp->dev); + pp->disconnected = NOT_DISCONNECTED; + } if ((newstate != PATH_UP && newstate != PATH_GHOST && newstate != PATH_PENDING) && (pp->state == PATH_DELAYED)) { /* If path state become failed again cancel path delay state */ @@ -3022,6 +3167,21 @@ update_paths(struct vectors *vecs, int *num_paths_p, time_t start_secs) return CHECKER_FINISHED; } +/* + * Check if there are paths marked for purging. + */ +static bool +has_paths_to_purge(struct vectors *vecs) +{ + int i; + struct path *pp; + + vector_foreach_slot(vecs->pathvec, pp, i) + if (pp->disconnected == DISCONNECTED_NEEDS_PURGE) + return true; + return false; +} + static void enable_pathgroups(struct multipath *mpp) { struct pathgroup *pgp; @@ -3125,6 +3285,7 @@ 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 +3329,10 @@ 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 +3355,13 @@ 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 +3399,100 @@ checkerloop (void *ap) return NULL; } +/* + * Purge thread: removes disconnected paths by writing to sysfs. + * + * This thread is signaled by the checker thread when paths in + * DISCONNECTED_NEEDS_PURGE state 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). + * + * To avoid holding vecs->lock for extended periods and starving other + * threads, this function processes one path at a time: lock -> find one + * path -> downgrade to NO_PURGE -> unlock -> delete -> repeat. If no + * paths need purging, it waits for a signal. + */ +static void * +purgeloop (void *ap) +{ + struct vectors *vecs; + 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) { + struct purge_path_info purge_info = { .udev = NULL, .fd = -1 }; + bool found = false; + + /* + * Register cleanup handler first to ensure purge_info is + * always cleaned up, even if the thread is cancelled while + * holding the lock. + */ + pthread_cleanup_push(cleanup_purge_path_info, &purge_info); + pthread_cleanup_push(cleanup_lock, &vecs->lock); + lock(&vecs->lock); + pthread_testcancel(); + + vector_foreach_slot (vecs->pathvec, pp, i) { + if (pp->disconnected != DISCONNECTED_NEEDS_PURGE) + continue; + + /* + * Downgrade to NO_PURGE whether we succeed or fail. + * On success, we're purging it now. + * On failure, retrying is unlikely to help until + * the checker re-evaluates the path. + */ + pp->disconnected = DISCONNECTED_NO_PURGE; + + /* Try to prepare purge info for this path */ + if (prepare_purge_path_info(pp, &purge_info)) { + found = true; + condlog(2, "%s: purging disconnected path", pp->dev); + break; + } else { + condlog(3, "%s: failed to prepare purge info", pp->dev); + /* Continue looking for other purgeable paths */ + } + } + + lock_cleanup_pop(vecs->lock); + + /* + * Now we've released the lock. Do the sysfs operation + * without holding vecs->lock. This may block. + */ + if (found) + delete_path_sysfs(&purge_info); + pthread_cleanup_pop(1); + + /* + * If we didn't find a path to purge, wait for signal. + */ + if (!found) { + pthread_mutex_lock(&purge_mutex); + while (!devices_to_purge) { + condlog(4, "purgeloop waiting for work"); + pthread_cond_wait(&purge_cond, &purge_mutex); + } + devices_to_purge = 0; + 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 +3933,8 @@ 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 +3951,8 @@ 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 +4205,11 @@ 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; -- 2.52.0
