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Commit 28bc3b8c authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Jens Axboe
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drbd: Fix locking across all resources 



Instead of using a rwlock for synchronizing state changes across
resources, take the request locks of all resources for global state
changes.  Use resources_mutex to serialize global state changes.

This means that taking the request lock of a resource is now enough to
prevent changes of that resource.  (Previously, a read lock on the
global state lock was needed as well.)

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 1ec317d3

drivers/block/drbd/drbd_int.h

+4 −14
Original line number Diff line number Diff line
@@ -292,6 +292,9 @@ struct drbd_device_work { 


extern int drbd_wait_misc(struct drbd_device *, struct drbd_interval *);



extern void lock_all_resources(void);

extern void unlock_all_resources(void);



struct drbd_request {

	struct drbd_work w;

	struct drbd_device *device;
@@ -1418,7 +1421,7 @@ extern struct bio_set *drbd_md_io_bio_set; 
/* to allocate from that set */

extern struct bio *bio_alloc_drbd(gfp_t gfp_mask);



extern rwlock_t global_state_lock;

extern struct mutex resources_mutex;



extern int conn_lowest_minor(struct drbd_connection *connection);

extern enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsigned int minor);
@@ -1688,19 +1691,6 @@ static inline int drbd_peer_req_has_active_page(struct drbd_peer_request *peer_r 
	return 0;

}



static inline enum drbd_state_rv

_drbd_set_state(struct drbd_device *device, union drbd_state ns,

		enum chg_state_flags flags, struct completion *done)

{

	enum drbd_state_rv rv;



	read_lock(&global_state_lock);

	rv = __drbd_set_state(device, ns, flags, done);

	read_unlock(&global_state_lock);



	return rv;

}



static inline union drbd_state drbd_read_state(struct drbd_device *device)

{

	struct drbd_resource *resource = device->resource;

drivers/block/drbd/drbd_main.c

+23 −1
Original line number Diff line number Diff line
@@ -117,6 +117,7 @@ module_param_string(usermode_helper, usermode_helper, sizeof(usermode_helper), 0 
 */

struct idr drbd_devices;

struct list_head drbd_resources;

struct mutex resources_mutex;



struct kmem_cache *drbd_request_cache;

struct kmem_cache *drbd_ee_cache;	/* peer requests */
@@ -2923,7 +2924,7 @@ static int __init drbd_init(void) 
	drbd_proc = NULL; /* play safe for drbd_cleanup */

	idr_init(&drbd_devices);



	rwlock_init(&global_state_lock);

	mutex_init(&resources_mutex);

	INIT_LIST_HEAD(&drbd_resources);



	err = drbd_genl_register();
@@ -3746,6 +3747,27 @@ int drbd_wait_misc(struct drbd_device *device, struct drbd_interval *i) 
	return 0;

}



void lock_all_resources(void)

{

	struct drbd_resource *resource;

	int __maybe_unused i = 0;



	mutex_lock(&resources_mutex);

	local_irq_disable();

	for_each_resource(resource, &drbd_resources)

		spin_lock_nested(&resource->req_lock, i++);

}



void unlock_all_resources(void)

{

	struct drbd_resource *resource;



	for_each_resource(resource, &drbd_resources)

		spin_unlock(&resource->req_lock);

	local_irq_enable();

	mutex_unlock(&resources_mutex);

}



#ifdef CONFIG_DRBD_FAULT_INJECTION

/* Fault insertion support including random number generator shamelessly

 * stolen from kernel/rcutorture.c */

drivers/block/drbd/drbd_nl.c

+24 −21
Original line number Diff line number Diff line
@@ -1389,13 +1389,13 @@ int drbd_adm_disk_opts(struct sk_buff *skb, struct genl_info *info) 
		goto fail_unlock;

	}



	write_lock_irq(&global_state_lock);

	lock_all_resources();

	retcode = drbd_resync_after_valid(device, new_disk_conf->resync_after);

	if (retcode == NO_ERROR) {

		rcu_assign_pointer(device->ldev->disk_conf, new_disk_conf);

		drbd_resync_after_changed(device);

	}

	write_unlock_irq(&global_state_lock);

	unlock_all_resources();



	if (retcode != NO_ERROR)

		goto fail_unlock;
@@ -1539,18 +1539,13 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 
		goto fail;

	}



	write_lock_irq(&global_state_lock);

	retcode = drbd_resync_after_valid(device, new_disk_conf->resync_after);

	if (retcode != NO_ERROR)

		goto fail_unlock;



	rcu_read_lock();

	nc = rcu_dereference(connection->net_conf);

	if (nc) {

		if (new_disk_conf->fencing == FP_STONITH && nc->wire_protocol == DRBD_PROT_A) {

			rcu_read_unlock();

			retcode = ERR_STONITH_AND_PROT_A;

			goto fail_unlock;

			goto fail;

		}

	}

	rcu_read_unlock();
@@ -1561,7 +1556,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 
		drbd_err(device, "open(\"%s\") failed with %ld\n", new_disk_conf->backing_dev,

			PTR_ERR(bdev));

		retcode = ERR_OPEN_DISK;

		goto fail_unlock;

		goto fail;

	}

	nbc->backing_bdev = bdev;
@@ -1581,7 +1576,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 
		drbd_err(device, "open(\"%s\") failed with %ld\n", new_disk_conf->meta_dev,

			PTR_ERR(bdev));

		retcode = ERR_OPEN_MD_DISK;

		goto fail_unlock;

		goto fail;

	}

	nbc->md_bdev = bdev;
@@ -1589,7 +1584,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 
	    (new_disk_conf->meta_dev_idx == DRBD_MD_INDEX_INTERNAL ||

	     new_disk_conf->meta_dev_idx == DRBD_MD_INDEX_FLEX_INT)) {

		retcode = ERR_MD_IDX_INVALID;

		goto fail_unlock;

		goto fail;

	}



	resync_lru = lc_create("resync", drbd_bm_ext_cache,
@@ -1597,14 +1592,14 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 
			offsetof(struct bm_extent, lce));

	if (!resync_lru) {

		retcode = ERR_NOMEM;

		goto fail_unlock;

		goto fail;

	}



	/* Read our meta data super block early.

	 * This also sets other on-disk offsets. */

	retcode = drbd_md_read(device, nbc);

	if (retcode != NO_ERROR)

		goto fail_unlock;

		goto fail;



	if (new_disk_conf->al_extents < DRBD_AL_EXTENTS_MIN)

		new_disk_conf->al_extents = DRBD_AL_EXTENTS_MIN;
@@ -1616,7 +1611,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 
			(unsigned long long) drbd_get_max_capacity(nbc),

			(unsigned long long) new_disk_conf->disk_size);

		retcode = ERR_DISK_TOO_SMALL;

		goto fail_unlock;

		goto fail;

	}



	if (new_disk_conf->meta_dev_idx < 0) {
@@ -1633,7 +1628,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 
		drbd_warn(device, "refusing attach: md-device too small, "

		     "at least %llu sectors needed for this meta-disk type\n",

		     (unsigned long long) min_md_device_sectors);

		goto fail_unlock;

		goto fail;

	}



	/* Make sure the new disk is big enough
@@ -1641,7 +1636,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 
	if (drbd_get_max_capacity(nbc) <

	    drbd_get_capacity(device->this_bdev)) {

		retcode = ERR_DISK_TOO_SMALL;

		goto fail_unlock;

		goto fail;

	}



	nbc->known_size = drbd_get_capacity(nbc->backing_bdev);
@@ -1671,7 +1666,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 
	retcode = rv;  /* FIXME: Type mismatch. */

	drbd_resume_io(device);

	if (rv < SS_SUCCESS)

		goto fail_unlock;

		goto fail;



	if (!get_ldev_if_state(device, D_ATTACHING))

		goto force_diskless;
@@ -1706,6 +1701,13 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 
		goto force_diskless_dec;

	}



	lock_all_resources();

	retcode = drbd_resync_after_valid(device, new_disk_conf->resync_after);

	if (retcode != NO_ERROR) {

		unlock_all_resources();

		goto force_diskless_dec;

	}



	/* Reset the "barriers don't work" bits here, then force meta data to

	 * be written, to ensure we determine if barriers are supported. */

	if (new_disk_conf->md_flushes)
@@ -1728,6 +1730,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 


	drbd_resync_after_changed(device);

	drbd_bump_write_ordering(device->resource, device->ldev, WO_BDEV_FLUSH);

	unlock_all_resources();



	if (drbd_md_test_flag(device->ldev, MDF_CRASHED_PRIMARY))

		set_bit(CRASHED_PRIMARY, &device->flags);
@@ -1850,8 +1853,6 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 
	if (rv < SS_SUCCESS)

		goto force_diskless_dec;



	write_unlock(&global_state_lock);



	mod_timer(&device->request_timer, jiffies + HZ);



	if (device->state.role == R_PRIMARY)
@@ -1874,8 +1875,6 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info) 
 force_diskless:

	drbd_force_state(device, NS(disk, D_DISKLESS));

	drbd_md_sync(device);

 fail_unlock:

	write_unlock_irq(&global_state_lock);

 fail:

	conn_reconfig_done(connection);

	if (nbc) {
@@ -3453,8 +3452,10 @@ int drbd_adm_new_resource(struct sk_buff *skb, struct genl_info *info) 
	}



	/* not yet safe for genl_family.parallel_ops */

	mutex_lock(&resources_mutex);

	if (!conn_create(adm_ctx.resource_name, &res_opts))

		retcode = ERR_NOMEM;

	mutex_unlock(&resources_mutex);

out:

	drbd_adm_finish(&adm_ctx, info, retcode);

	return 0;
@@ -3545,7 +3546,9 @@ static int adm_del_resource(struct drbd_resource *resource) 
	if (!idr_is_empty(&resource->devices))

		return ERR_RES_IN_USE;



	mutex_lock(&resources_mutex);

	list_del_rcu(&resource->resources);

	mutex_unlock(&resources_mutex);

	/* Make sure all threads have actually stopped: state handling only

	 * does drbd_thread_stop_nowait(). */

	list_for_each_entry(connection, &resource->connections, connections)

drivers/block/drbd/drbd_state.c

+7 −7
Original line number Diff line number Diff line
@@ -937,7 +937,7 @@ void drbd_resume_al(struct drbd_device *device) 
		drbd_info(device, "Resumed AL updates\n");

}



/* helper for __drbd_set_state */

/* helper for _drbd_set_state */

static void set_ov_position(struct drbd_device *device, enum drbd_conns cs)

{

	if (first_peer_device(device)->connection->agreed_pro_version < 90)
@@ -965,16 +965,16 @@ static void set_ov_position(struct drbd_device *device, enum drbd_conns cs) 
}



/**

 * __drbd_set_state() - Set a new DRBD state

 * _drbd_set_state() - Set a new DRBD state

 * @device:	DRBD device.

 * @ns:		new state.

 * @flags:	Flags

 * @done:	Optional completion, that will get completed after the after_state_ch() finished

 *

 * Caller needs to hold req_lock, and global_state_lock. Do not call directly.

 * Caller needs to hold req_lock. Do not call directly.

 */

enum drbd_state_rv

__drbd_set_state(struct drbd_device *device, union drbd_state ns,

_drbd_set_state(struct drbd_device *device, union drbd_state ns,

	        enum chg_state_flags flags, struct completion *done)

{

	struct drbd_peer_device *peer_device = first_peer_device(device);
@@ -1444,7 +1444,7 @@ static void after_state_ch(struct drbd_device *device, union drbd_state os, 
	if (os.disk != D_FAILED && ns.disk == D_FAILED) {

		enum drbd_io_error_p eh = EP_PASS_ON;

		int was_io_error = 0;

		/* corresponding get_ldev was in __drbd_set_state, to serialize

		/* corresponding get_ldev was in _drbd_set_state, to serialize

		 * our cleanup here with the transition to D_DISKLESS.

		 * But is is still not save to dreference ldev here, since

		 * we might come from an failed Attach before ldev was set. */
@@ -1759,7 +1759,7 @@ conn_set_state(struct drbd_connection *connection, union drbd_state mask, union 
		if (flags & CS_IGN_OUTD_FAIL && ns.disk == D_OUTDATED && os.disk < D_OUTDATED)

			ns.disk = os.disk;



		rv = __drbd_set_state(device, ns, flags, NULL);

		rv = _drbd_set_state(device, ns, flags, NULL);

		if (rv < SS_SUCCESS)

			BUG();

drivers/block/drbd/drbd_state.h

+3 −3
Original line number Diff line number Diff line
@@ -122,7 +122,7 @@ extern enum drbd_state_rv 
_drbd_request_state_holding_state_mutex(struct drbd_device *, union drbd_state,

					union drbd_state, enum chg_state_flags);



extern enum drbd_state_rv __drbd_set_state(struct drbd_device *, union drbd_state,

extern enum drbd_state_rv _drbd_set_state(struct drbd_device *, union drbd_state,

					  enum chg_state_flags,

					  struct completion *done);

extern void print_st_err(struct drbd_device *, union drbd_state,