diff options
| -rw-r--r-- | Documentation/device-mapper/dm-uevent.txt | 97 | ||||
| -rw-r--r-- | drivers/md/dm-uevent.c | 150 | ||||
| -rw-r--r-- | drivers/md/dm-uevent.h | 18 | ||||
| -rw-r--r-- | drivers/md/dm.c | 28 | ||||
| -rw-r--r-- | include/linux/device-mapper.h | 2 |
5 files changed, 295 insertions, 0 deletions
diff --git a/Documentation/device-mapper/dm-uevent.txt b/Documentation/device-mapper/dm-uevent.txt new file mode 100644 index 000000000000..07edbd85c714 --- /dev/null +++ b/Documentation/device-mapper/dm-uevent.txt @@ -0,0 +1,97 @@ +The device-mapper uevent code adds the capability to device-mapper to create +and send kobject uevents (uevents). Previously device-mapper events were only +available through the ioctl interface. The advantage of the uevents interface +is the event contains environment attributes providing increased context for +the event avoiding the need to query the state of the device-mapper device after +the event is received. + +There are two functions currently for device-mapper events. The first function +listed creates the event and the second function sends the event(s). + +void dm_path_uevent(enum dm_uevent_type event_type, struct dm_target *ti, + const char *path, unsigned nr_valid_paths) + +void dm_send_uevents(struct list_head *events, struct kobject *kobj) + + +The variables added to the uevent environment are: + +Variable Name: DM_TARGET +Uevent Action(s): KOBJ_CHANGE +Type: string +Description: +Value: Name of device-mapper target that generated the event. + +Variable Name: DM_ACTION +Uevent Action(s): KOBJ_CHANGE +Type: string +Description: +Value: Device-mapper specific action that caused the uevent action. + PATH_FAILED - A path has failed. + PATH_REINSTATED - A path has been reinstated. + +Variable Name: DM_SEQNUM +Uevent Action(s): KOBJ_CHANGE +Type: unsigned integer +Description: A sequence number for this specific device-mapper device. +Value: Valid unsigned integer range. + +Variable Name: DM_PATH +Uevent Action(s): KOBJ_CHANGE +Type: string +Description: Major and minor number of the path device pertaining to this +event. +Value: Path name in the form of "Major:Minor" + +Variable Name: DM_NR_VALID_PATHS +Uevent Action(s): KOBJ_CHANGE +Type: unsigned integer +Description: +Value: Valid unsigned integer range. + +Variable Name: DM_NAME +Uevent Action(s): KOBJ_CHANGE +Type: string +Description: Name of the device-mapper device. +Value: Name + +Variable Name: DM_UUID +Uevent Action(s): KOBJ_CHANGE +Type: string +Description: UUID of the device-mapper device. +Value: UUID. (Empty string if there isn't one.) + +An example of the uevents generated as captured by udevmonitor is shown +below. + +1.) Path failure. +UEVENT[1192521009.711215] change@/block/dm-3 +ACTION=change +DEVPATH=/block/dm-3 +SUBSYSTEM=block +DM_TARGET=multipath +DM_ACTION=PATH_FAILED +DM_SEQNUM=1 +DM_PATH=8:32 +DM_NR_VALID_PATHS=0 +DM_NAME=mpath2 +DM_UUID=mpath-35333333000002328 +MINOR=3 +MAJOR=253 +SEQNUM=1130 + +2.) Path reinstate. +UEVENT[1192521132.989927] change@/block/dm-3 +ACTION=change +DEVPATH=/block/dm-3 +SUBSYSTEM=block +DM_TARGET=multipath +DM_ACTION=PATH_REINSTATED +DM_SEQNUM=2 +DM_PATH=8:32 +DM_NR_VALID_PATHS=1 +DM_NAME=mpath2 +DM_UUID=mpath-35333333000002328 +MINOR=3 +MAJOR=253 +SEQNUM=1131 diff --git a/drivers/md/dm-uevent.c b/drivers/md/dm-uevent.c index 53200c96bcb4..50377e5dc2a3 100644 --- a/drivers/md/dm-uevent.c +++ b/drivers/md/dm-uevent.c @@ -21,12 +21,22 @@ #include <linux/list.h> #include <linux/slab.h> #include <linux/kobject.h> +#include <linux/dm-ioctl.h> #include "dm.h" #include "dm-uevent.h" #define DM_MSG_PREFIX "uevent" +static const struct { + enum dm_uevent_type type; + enum kobject_action action; + char *name; +} _dm_uevent_type_names[] = { + {DM_UEVENT_PATH_FAILED, KOBJ_CHANGE, "PATH_FAILED"}, + {DM_UEVENT_PATH_REINSTATED, KOBJ_CHANGE, "PATH_REINSTATED"}, +}; + static struct kmem_cache *_dm_event_cache; struct dm_uevent { @@ -34,6 +44,8 @@ struct dm_uevent { enum kobject_action action; struct kobj_uevent_env ku_env; struct list_head elist; + char name[DM_NAME_LEN]; + char uuid[DM_UUID_LEN]; }; static void dm_uevent_free(struct dm_uevent *event) @@ -55,6 +67,144 @@ static struct dm_uevent *dm_uevent_alloc(struct mapped_device *md) return event; } +static struct dm_uevent *dm_build_path_uevent(struct mapped_device *md, + struct dm_target *ti, + enum kobject_action action, + const char *dm_action, + const char *path, + unsigned nr_valid_paths) +{ + struct dm_uevent *event; + + event = dm_uevent_alloc(md); + if (!event) { + DMERR("%s: dm_uevent_alloc() failed", __FUNCTION__); + goto err_nomem; + } + + event->action = action; + + if (add_uevent_var(&event->ku_env, "DM_TARGET=%s", ti->type->name)) { + DMERR("%s: add_uevent_var() for DM_TARGET failed", + __FUNCTION__); + goto err_add; + } + + if (add_uevent_var(&event->ku_env, "DM_ACTION=%s", dm_action)) { + DMERR("%s: add_uevent_var() for DM_ACTION failed", + __FUNCTION__); + goto err_add; + } + + if (add_uevent_var(&event->ku_env, "DM_SEQNUM=%u", + dm_next_uevent_seq(md))) { + DMERR("%s: add_uevent_var() for DM_SEQNUM failed", + __FUNCTION__); + goto err_add; + } + + if (add_uevent_var(&event->ku_env, "DM_PATH=%s", path)) { + DMERR("%s: add_uevent_var() for DM_PATH failed", __FUNCTION__); + goto err_add; + } + + if (add_uevent_var(&event->ku_env, "DM_NR_VALID_PATHS=%d", + nr_valid_paths)) { + DMERR("%s: add_uevent_var() for DM_NR_VALID_PATHS failed", + __FUNCTION__); + goto err_add; + } + + return event; + +err_add: + dm_uevent_free(event); +err_nomem: + return ERR_PTR(-ENOMEM); +} + +/** + * dm_send_uevents - send uevents for given list + * + * @events: list of events to send + * @kobj: kobject generating event + * + */ +void dm_send_uevents(struct list_head *events, struct kobject *kobj) +{ + int r; + struct dm_uevent *event, *next; + + list_for_each_entry_safe(event, next, events, elist) { + list_del_init(&event->elist); + + /* + * Need to call dm_copy_name_and_uuid from here for now. + * Context of previous var adds and locking used for + * hash_cell not compatable. + */ + if (dm_copy_name_and_uuid(event->md, event->name, + event->uuid)) { + DMERR("%s: dm_copy_name_and_uuid() failed", + __FUNCTION__); + goto uevent_free; + } + + if (add_uevent_var(&event->ku_env, "DM_NAME=%s", event->name)) { + DMERR("%s: add_uevent_var() for DM_NAME failed", + __FUNCTION__); + goto uevent_free; + } + + if (add_uevent_var(&event->ku_env, "DM_UUID=%s", event->uuid)) { + DMERR("%s: add_uevent_var() for DM_UUID failed", + __FUNCTION__); + goto uevent_free; + } + + r = kobject_uevent_env(kobj, event->action, event->ku_env.envp); + if (r) + DMERR("%s: kobject_uevent_env failed", __FUNCTION__); +uevent_free: + dm_uevent_free(event); + } +} +EXPORT_SYMBOL_GPL(dm_send_uevents); + +/** + * dm_path_uevent - called to create a new path event and queue it + * + * @event_type: path event type enum + * @ti: pointer to a dm_target + * @path: string containing pathname + * @nr_valid_paths: number of valid paths remaining + * + */ +void dm_path_uevent(enum dm_uevent_type event_type, struct dm_target *ti, + const char *path, unsigned nr_valid_paths) +{ + struct mapped_device *md = dm_table_get_md(ti->table); + struct dm_uevent *event; + + if (event_type >= ARRAY_SIZE(_dm_uevent_type_names)) { + DMERR("%s: Invalid event_type %d", __FUNCTION__, event_type); + goto out; + } + + event = dm_build_path_uevent(md, ti, + _dm_uevent_type_names[event_type].action, + _dm_uevent_type_names[event_type].name, + path, nr_valid_paths); + if (IS_ERR(event)) + goto out; + + dm_uevent_add(md, &event->elist); + +out: + dm_put(md); +} +EXPORT_SYMBOL_GPL(dm_path_uevent); + int dm_uevent_init(void) { _dm_event_cache = KMEM_CACHE(dm_uevent, 0); diff --git a/drivers/md/dm-uevent.h b/drivers/md/dm-uevent.h index 9d776836489b..2eccc8bd671a 100644 --- a/drivers/md/dm-uevent.h +++ b/drivers/md/dm-uevent.h @@ -21,10 +21,19 @@ #ifndef DM_UEVENT_H #define DM_UEVENT_H +enum dm_uevent_type { + DM_UEVENT_PATH_FAILED, + DM_UEVENT_PATH_REINSTATED, +}; + #ifdef CONFIG_DM_UEVENT extern int dm_uevent_init(void); extern void dm_uevent_exit(void); +extern void dm_send_uevents(struct list_head *events, struct kobject *kobj); +extern void dm_path_uevent(enum dm_uevent_type event_type, + struct dm_target *ti, const char *path, + unsigned nr_valid_paths); #else @@ -35,6 +44,15 @@ static inline int dm_uevent_init(void) static inline void dm_uevent_exit(void) { } +static inline void dm_send_uevents(struct list_head *events, + struct kobject *kobj) +{ +} +static inline void dm_path_uevent(enum dm_uevent_type event_type, + struct dm_target *ti, const char *path, + unsigned nr_valid_paths) +{ +} #endif /* CONFIG_DM_UEVENT */ diff --git a/drivers/md/dm.c b/drivers/md/dm.c index bb5c1eaca52b..07cbbb8eb3e0 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -113,6 +113,9 @@ struct mapped_device { */ atomic_t event_nr; wait_queue_head_t eventq; + atomic_t uevent_seq; + struct list_head uevent_list; + spinlock_t uevent_lock; /* Protect access to uevent_list */ /* * freeze/thaw support require holding onto a super block @@ -985,6 +988,9 @@ static struct mapped_device *alloc_dev(int minor) atomic_set(&md->holders, 1); atomic_set(&md->open_count, 0); atomic_set(&md->event_nr, 0); + atomic_set(&md->uevent_seq, 0); + INIT_LIST_HEAD(&md->uevent_list); + spin_lock_init(&md->uevent_lock); md->queue = blk_alloc_queue(GFP_KERNEL); if (!md->queue) @@ -1083,8 +1089,16 @@ static void free_dev(struct mapped_device *md) */ static void event_callback(void *context) { + unsigned long flags; + LIST_HEAD(uevents); struct mapped_device *md = (struct mapped_device *) context; + spin_lock_irqsave(&md->uevent_lock, flags); + list_splice_init(&md->uevent_list, &uevents); + spin_unlock_irqrestore(&md->uevent_lock, flags); + + dm_send_uevents(&uevents, &md->disk->kobj); + atomic_inc(&md->event_nr); wake_up(&md->eventq); } @@ -1502,6 +1516,11 @@ out: /*----------------------------------------------------------------- * Event notification. *---------------------------------------------------------------*/ +uint32_t dm_next_uevent_seq(struct mapped_device *md) +{ + return atomic_add_return(1, &md->uevent_seq); +} + uint32_t dm_get_event_nr(struct mapped_device *md) { return atomic_read(&md->event_nr); @@ -1513,6 +1532,15 @@ int dm_wait_event(struct mapped_device *md, int event_nr) (event_nr != atomic_read(&md->event_nr))); } +void dm_uevent_add(struct mapped_device *md, struct list_head *elist) +{ + unsigned long flags; + + spin_lock_irqsave(&md->uevent_lock, flags); + list_add(elist, &md->uevent_list); + spin_unlock_irqrestore(&md->uevent_lock, flags); +} + /* * The gendisk is only valid as long as you have a reference * count on 'md'. diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index 8b3c7cdc599c..37c66d1254b5 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -183,6 +183,8 @@ int dm_resume(struct mapped_device *md); */ uint32_t dm_get_event_nr(struct mapped_device *md); int dm_wait_event(struct mapped_device *md, int event_nr); +uint32_t dm_next_uevent_seq(struct mapped_device *md); +void dm_uevent_add(struct mapped_device *md, struct list_head *elist); /* * Info functions. |