1/*
  2 * Copyright (C) 2006-2009 Red Hat, Inc.
  3 *
  4 * This file is released under the LGPL.
  5 */
  6
  7#include <linux/bio.h>
  8#include <linux/slab.h>
  9#include <linux/jiffies.h>
 10#include <linux/dm-dirty-log.h>
 11#include <linux/device-mapper.h>
 12#include <linux/dm-log-userspace.h>
 13#include <linux/module.h>
 14#include <linux/workqueue.h>
 15
 16#include "dm-log-userspace-transfer.h"
 17
 18#define DM_LOG_USERSPACE_VSN "1.3.0"
 19
 20#define FLUSH_ENTRY_POOL_SIZE 16
 21
 22struct dm_dirty_log_flush_entry {
 23	int type;
 24	region_t region;
 25	struct list_head list;
 26};
 27
 28/*
 29 * This limit on the number of mark and clear request is, to a degree,
 30 * arbitrary.  However, there is some basis for the choice in the limits
 31 * imposed on the size of data payload by dm-log-userspace-transfer.c:
 32 * dm_consult_userspace().
 33 */
 34#define MAX_FLUSH_GROUP_COUNT 32
 35
 36struct log_c {
 37	struct dm_target *ti;
 38	struct dm_dev *log_dev;
 39
 40	char *usr_argv_str;
 41	uint32_t usr_argc;
 42
 43	uint32_t region_size;
 44	region_t region_count;
 45	uint64_t luid;
 46	char uuid[DM_UUID_LEN];
 47
 48	/*
 49	 * Mark and clear requests are held until a flush is issued
 50	 * so that we can group, and thereby limit, the amount of
 51	 * network traffic between kernel and userspace.  The 'flush_lock'
 52	 * is used to protect these lists.
 53	 */
 54	spinlock_t flush_lock;
 55	struct list_head mark_list;
 56	struct list_head clear_list;
 57
 58	/*
 59	 * in_sync_hint gets set when doing is_remote_recovering.  It
 60	 * represents the first region that needs recovery.  IOW, the
 61	 * first zero bit of sync_bits.  This can be useful for to limit
 62	 * traffic for calls like is_remote_recovering and get_resync_work,
 63	 * but be take care in its use for anything else.
 64	 */
 65	uint64_t in_sync_hint;
 66
 67	/*
 68	 * Workqueue for flush of clear region requests.
 69	 */
 70	struct workqueue_struct *dmlog_wq;
 71	struct delayed_work flush_log_work;
 72	atomic_t sched_flush;
 73
 74	/*
 75	 * Combine userspace flush and mark requests for efficiency.
 76	 */
 77	uint32_t integrated_flush;
 78
 79	mempool_t flush_entry_pool;
 80};
 81
 82static struct kmem_cache *_flush_entry_cache;
 83
 84static int userspace_do_request(struct log_c *lc, const char *uuid,
 85				int request_type, char *data, size_t data_size,
 86				char *rdata, size_t *rdata_size)
 87{
 88	int r;
 89
 90	/*
 91	 * If the server isn't there, -ESRCH is returned,
 92	 * and we must keep trying until the server is
 93	 * restored.
 94	 */
 95retry:
 96	r = dm_consult_userspace(uuid, lc->luid, request_type, data,
 97				 data_size, rdata, rdata_size);
 98
 99	if (r != -ESRCH)
100		return r;
101
102	DMERR(" Userspace log server not found.");
103	while (1) {
104		set_current_state(TASK_INTERRUPTIBLE);
105		schedule_timeout(2*HZ);
106		DMWARN("Attempting to contact userspace log server...");
107		r = dm_consult_userspace(uuid, lc->luid, DM_ULOG_CTR,
108					 lc->usr_argv_str,
109					 strlen(lc->usr_argv_str) + 1,
110					 NULL, NULL);
111		if (!r)
112			break;
113	}
114	DMINFO("Reconnected to userspace log server... DM_ULOG_CTR complete");
115	r = dm_consult_userspace(uuid, lc->luid, DM_ULOG_RESUME, NULL,
116				 0, NULL, NULL);
117	if (!r)
118		goto retry;
119
120	DMERR("Error trying to resume userspace log: %d", r);
121
122	return -ESRCH;
123}
124
125static int build_constructor_string(struct dm_target *ti,
126				    unsigned argc, char **argv,
127				    char **ctr_str)
128{
129	int i, str_size;
130	char *str = NULL;
131
132	*ctr_str = NULL;
133
134	/*
135	 * Determine overall size of the string.
136	 */
137	for (i = 0, str_size = 0; i < argc; i++)
138		str_size += strlen(argv[i]) + 1; /* +1 for space between args */
139
140	str_size += 20; /* Max number of chars in a printed u64 number */
141
142	str = kzalloc(str_size, GFP_KERNEL);
143	if (!str) {
144		DMWARN("Unable to allocate memory for constructor string");
145		return -ENOMEM;
146	}
147
148	str_size = sprintf(str, "%llu", (unsigned long long)ti->len);
149	for (i = 0; i < argc; i++)
150		str_size += sprintf(str + str_size, " %s", argv[i]);
151
152	*ctr_str = str;
153	return str_size;
154}
155
156static void do_flush(struct work_struct *work)
157{
158	int r;
159	struct log_c *lc = container_of(work, struct log_c, flush_log_work.work);
160
161	atomic_set(&lc->sched_flush, 0);
162
163	r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH, NULL, 0, NULL, NULL);
164
165	if (r)
166		dm_table_event(lc->ti->table);
167}
168
169/*
170 * userspace_ctr
171 *
172 * argv contains:
173 *	<UUID> [integrated_flush] <other args>
174 * Where 'other args' are the userspace implementation-specific log
175 * arguments.
176 *
177 * Example:
178 *	<UUID> [integrated_flush] clustered-disk <arg count> <log dev>
179 *	<region_size> [[no]sync]
180 *
181 * This module strips off the <UUID> and uses it for identification
182 * purposes when communicating with userspace about a log.
183 *
184 * If integrated_flush is defined, the kernel combines flush
185 * and mark requests.
186 *
187 * The rest of the line, beginning with 'clustered-disk', is passed
188 * to the userspace ctr function.
189 */
190static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti,
191			 unsigned argc, char **argv)
192{
193	int r = 0;
194	int str_size;
195	char *ctr_str = NULL;
196	struct log_c *lc = NULL;
197	uint64_t rdata;
198	size_t rdata_size = sizeof(rdata);
199	char *devices_rdata = NULL;
200	size_t devices_rdata_size = DM_NAME_LEN;
201
202	if (argc < 3) {
203		DMWARN("Too few arguments to userspace dirty log");
204		return -EINVAL;
205	}
206
207	lc = kzalloc(sizeof(*lc), GFP_KERNEL);
208	if (!lc) {
209		DMWARN("Unable to allocate userspace log context.");
210		return -ENOMEM;
211	}
212
213	/* The ptr value is sufficient for local unique id */
214	lc->luid = (unsigned long)lc;
215
216	lc->ti = ti;
217
218	if (strlen(argv[0]) > (DM_UUID_LEN - 1)) {
219		DMWARN("UUID argument too long.");
220		kfree(lc);
221		return -EINVAL;
222	}
223
224	lc->usr_argc = argc;
225
226	strncpy(lc->uuid, argv[0], DM_UUID_LEN);
227	argc--;
228	argv++;
229	spin_lock_init(&lc->flush_lock);
230	INIT_LIST_HEAD(&lc->mark_list);
231	INIT_LIST_HEAD(&lc->clear_list);
232
233	if (!strcasecmp(argv[0], "integrated_flush")) {
234		lc->integrated_flush = 1;
235		argc--;
236		argv++;
237	}
238
239	str_size = build_constructor_string(ti, argc, argv, &ctr_str);
240	if (str_size < 0) {
241		kfree(lc);
242		return str_size;
243	}
244
245	devices_rdata = kzalloc(devices_rdata_size, GFP_KERNEL);
246	if (!devices_rdata) {
247		DMERR("Failed to allocate memory for device information");
248		r = -ENOMEM;
249		goto out;
250	}
251
252	r = mempool_init_slab_pool(&lc->flush_entry_pool, FLUSH_ENTRY_POOL_SIZE,
253				   _flush_entry_cache);
254	if (r) {
255		DMERR("Failed to create flush_entry_pool");
256		goto out;
257	}
258
259	/*
260	 * Send table string and get back any opened device.
261	 */
262	r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_CTR,
263				 ctr_str, str_size,
264				 devices_rdata, &devices_rdata_size);
265
266	if (r < 0) {
267		if (r == -ESRCH)
268			DMERR("Userspace log server not found");
269		else
270			DMERR("Userspace log server failed to create log");
271		goto out;
272	}
273
274	/* Since the region size does not change, get it now */
275	rdata_size = sizeof(rdata);
276	r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_GET_REGION_SIZE,
277				 NULL, 0, (char *)&rdata, &rdata_size);
278
279	if (r) {
280		DMERR("Failed to get region size of dirty log");
281		goto out;
282	}
283
284	lc->region_size = (uint32_t)rdata;
285	lc->region_count = dm_sector_div_up(ti->len, lc->region_size);
286
287	if (devices_rdata_size) {
288		if (devices_rdata[devices_rdata_size - 1] != '\0') {
289			DMERR("DM_ULOG_CTR device return string not properly terminated");
290			r = -EINVAL;
291			goto out;
292		}
293		r = dm_get_device(ti, devices_rdata,
294				  dm_table_get_mode(ti->table), &lc->log_dev);
295		if (r)
296			DMERR("Failed to register %s with device-mapper",
297			      devices_rdata);
298	}
299
300	if (lc->integrated_flush) {
301		lc->dmlog_wq = alloc_workqueue("dmlogd", WQ_MEM_RECLAIM, 0);
302		if (!lc->dmlog_wq) {
303			DMERR("couldn't start dmlogd");
304			r = -ENOMEM;
305			goto out;
306		}
307
308		INIT_DELAYED_WORK(&lc->flush_log_work, do_flush);
309		atomic_set(&lc->sched_flush, 0);
310	}
311
312out:
313	kfree(devices_rdata);
314	if (r) {
315		mempool_exit(&lc->flush_entry_pool);
316		kfree(lc);
317		kfree(ctr_str);
318	} else {
319		lc->usr_argv_str = ctr_str;
320		log->context = lc;
321	}
322
323	return r;
324}
325
326static void userspace_dtr(struct dm_dirty_log *log)
327{
328	struct log_c *lc = log->context;
329
330	if (lc->integrated_flush) {
331		/* flush workqueue */
332		if (atomic_read(&lc->sched_flush))
333			flush_delayed_work(&lc->flush_log_work);
334
335		destroy_workqueue(lc->dmlog_wq);
336	}
337
338	(void) dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_DTR,
339				    NULL, 0, NULL, NULL);
340
341	if (lc->log_dev)
342		dm_put_device(lc->ti, lc->log_dev);
343
344	mempool_exit(&lc->flush_entry_pool);
345
346	kfree(lc->usr_argv_str);
347	kfree(lc);
348
349	return;
350}
351
352static int userspace_presuspend(struct dm_dirty_log *log)
353{
354	int r;
355	struct log_c *lc = log->context;
356
357	r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_PRESUSPEND,
358				 NULL, 0, NULL, NULL);
359
360	return r;
361}
362
363static int userspace_postsuspend(struct dm_dirty_log *log)
364{
365	int r;
366	struct log_c *lc = log->context;
367
368	/*
369	 * Run planned flush earlier.
370	 */
371	if (lc->integrated_flush && atomic_read(&lc->sched_flush))
372		flush_delayed_work(&lc->flush_log_work);
373
374	r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_POSTSUSPEND,
375				 NULL, 0, NULL, NULL);
376
377	return r;
378}
379
380static int userspace_resume(struct dm_dirty_log *log)
381{
382	int r;
383	struct log_c *lc = log->context;
384
385	lc->in_sync_hint = 0;
386	r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_RESUME,
387				 NULL, 0, NULL, NULL);
388
389	return r;
390}
391
392static uint32_t userspace_get_region_size(struct dm_dirty_log *log)
393{
394	struct log_c *lc = log->context;
395
396	return lc->region_size;
397}
398
399/*
400 * userspace_is_clean
401 *
402 * Check whether a region is clean.  If there is any sort of
403 * failure when consulting the server, we return not clean.
404 *
405 * Returns: 1 if clean, 0 otherwise
406 */
407static int userspace_is_clean(struct dm_dirty_log *log, region_t region)
408{
409	int r;
410	uint64_t region64 = (uint64_t)region;
411	int64_t is_clean;
412	size_t rdata_size;
413	struct log_c *lc = log->context;
414
415	rdata_size = sizeof(is_clean);
416	r = userspace_do_request(lc, lc->uuid, DM_ULOG_IS_CLEAN,
417				 (char *)&region64, sizeof(region64),
418				 (char *)&is_clean, &rdata_size);
419
420	return (r) ? 0 : (int)is_clean;
421}
422
423/*
424 * userspace_in_sync
425 *
426 * Check if the region is in-sync.  If there is any sort
427 * of failure when consulting the server, we assume that
428 * the region is not in sync.
429 *
430 * If 'can_block' is set, return immediately
431 *
432 * Returns: 1 if in-sync, 0 if not-in-sync, -EWOULDBLOCK
433 */
434static int userspace_in_sync(struct dm_dirty_log *log, region_t region,
435			     int can_block)
436{
437	int r;
438	uint64_t region64 = region;
439	int64_t in_sync;
440	size_t rdata_size;
441	struct log_c *lc = log->context;
442
443	/*
444	 * We can never respond directly - even if in_sync_hint is
445	 * set.  This is because another machine could see a device
446	 * failure and mark the region out-of-sync.  If we don't go
447	 * to userspace to ask, we might think the region is in-sync
448	 * and allow a read to pick up data that is stale.  (This is
449	 * very unlikely if a device actually fails; but it is very
450	 * likely if a connection to one device from one machine fails.)
451	 *
452	 * There still might be a problem if the mirror caches the region
453	 * state as in-sync... but then this call would not be made.  So,
454	 * that is a mirror problem.
455	 */
456	if (!can_block)
457		return -EWOULDBLOCK;
458
459	rdata_size = sizeof(in_sync);
460	r = userspace_do_request(lc, lc->uuid, DM_ULOG_IN_SYNC,
461				 (char *)&region64, sizeof(region64),
462				 (char *)&in_sync, &rdata_size);
463	return (r) ? 0 : (int)in_sync;
464}
465
466static int flush_one_by_one(struct log_c *lc, struct list_head *flush_list)
467{
468	int r = 0;
469	struct dm_dirty_log_flush_entry *fe;
470
471	list_for_each_entry(fe, flush_list, list) {
472		r = userspace_do_request(lc, lc->uuid, fe->type,
473					 (char *)&fe->region,
474					 sizeof(fe->region),
475					 NULL, NULL);
476		if (r)
477			break;
478	}
479
480	return r;
481}
482
483static int flush_by_group(struct log_c *lc, struct list_head *flush_list,
484			  int flush_with_payload)
485{
486	int r = 0;
487	int count;
488	uint32_t type = 0;
489	struct dm_dirty_log_flush_entry *fe, *tmp_fe;
490	LIST_HEAD(tmp_list);
491	uint64_t group[MAX_FLUSH_GROUP_COUNT];
492
493	/*
494	 * Group process the requests
495	 */
496	while (!list_empty(flush_list)) {
497		count = 0;
498
499		list_for_each_entry_safe(fe, tmp_fe, flush_list, list) {
500			group[count] = fe->region;
501			count++;
502
503			list_move(&fe->list, &tmp_list);
504
505			type = fe->type;
506			if (count >= MAX_FLUSH_GROUP_COUNT)
507				break;
508		}
509
510		if (flush_with_payload) {
511			r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH,
512						 (char *)(group),
513						 count * sizeof(uint64_t),
514						 NULL, NULL);
515			/*
516			 * Integrated flush failed.
517			 */
518			if (r)
519				break;
520		} else {
521			r = userspace_do_request(lc, lc->uuid, type,
522						 (char *)(group),
523						 count * sizeof(uint64_t),
524						 NULL, NULL);
525			if (r) {
526				/*
527				 * Group send failed.  Attempt one-by-one.
528				 */
529				list_splice_init(&tmp_list, flush_list);
530				r = flush_one_by_one(lc, flush_list);
531				break;
532			}
533		}
534	}
535
536	/*
537	 * Must collect flush_entrys that were successfully processed
538	 * as a group so that they will be free'd by the caller.
539	 */
540	list_splice_init(&tmp_list, flush_list);
541
542	return r;
543}
544
545/*
546 * userspace_flush
547 *
548 * This function is ok to block.
549 * The flush happens in two stages.  First, it sends all
550 * clear/mark requests that are on the list.  Then it
551 * tells the server to commit them.  This gives the
552 * server a chance to optimise the commit, instead of
553 * doing it for every request.
554 *
555 * Additionally, we could implement another thread that
556 * sends the requests up to the server - reducing the
557 * load on flush.  Then the flush would have less in
558 * the list and be responsible for the finishing commit.
559 *
560 * Returns: 0 on success, < 0 on failure
561 */
562static int userspace_flush(struct dm_dirty_log *log)
563{
564	int r = 0;
565	unsigned long flags;
566	struct log_c *lc = log->context;
567	LIST_HEAD(mark_list);
568	LIST_HEAD(clear_list);
569	int mark_list_is_empty;
570	int clear_list_is_empty;
571	struct dm_dirty_log_flush_entry *fe, *tmp_fe;
572	mempool_t *flush_entry_pool = &lc->flush_entry_pool;
573
574	spin_lock_irqsave(&lc->flush_lock, flags);
575	list_splice_init(&lc->mark_list, &mark_list);
576	list_splice_init(&lc->clear_list, &clear_list);
577	spin_unlock_irqrestore(&lc->flush_lock, flags);
578
579	mark_list_is_empty = list_empty(&mark_list);
580	clear_list_is_empty = list_empty(&clear_list);
581
582	if (mark_list_is_empty && clear_list_is_empty)
583		return 0;
584
585	r = flush_by_group(lc, &clear_list, 0);
586	if (r)
587		goto out;
588
589	if (!lc->integrated_flush) {
590		r = flush_by_group(lc, &mark_list, 0);
591		if (r)
592			goto out;
593		r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH,
594					 NULL, 0, NULL, NULL);
595		goto out;
596	}
597
598	/*
599	 * Send integrated flush request with mark_list as payload.
600	 */
601	r = flush_by_group(lc, &mark_list, 1);
602	if (r)
603		goto out;
604
605	if (mark_list_is_empty && !atomic_read(&lc->sched_flush)) {
606		/*
607		 * When there are only clear region requests,
608		 * we schedule a flush in the future.
609		 */
610		queue_delayed_work(lc->dmlog_wq, &lc->flush_log_work, 3 * HZ);
611		atomic_set(&lc->sched_flush, 1);
612	} else {
613		/*
614		 * Cancel pending flush because we
615		 * have already flushed in mark_region.
616		 */
617		cancel_delayed_work(&lc->flush_log_work);
618		atomic_set(&lc->sched_flush, 0);
619	}
620
621out:
622	/*
623	 * We can safely remove these entries, even after failure.
624	 * Calling code will receive an error and will know that
625	 * the log facility has failed.
626	 */
627	list_for_each_entry_safe(fe, tmp_fe, &mark_list, list) {
628		list_del(&fe->list);
629		mempool_free(fe, flush_entry_pool);
630	}
631	list_for_each_entry_safe(fe, tmp_fe, &clear_list, list) {
632		list_del(&fe->list);
633		mempool_free(fe, flush_entry_pool);
634	}
635
636	if (r)
637		dm_table_event(lc->ti->table);
638
639	return r;
640}
641
642/*
643 * userspace_mark_region
644 *
645 * This function should avoid blocking unless absolutely required.
646 * (Memory allocation is valid for blocking.)
647 */
648static void userspace_mark_region(struct dm_dirty_log *log, region_t region)
649{
650	unsigned long flags;
651	struct log_c *lc = log->context;
652	struct dm_dirty_log_flush_entry *fe;
653
654	/* Wait for an allocation, but _never_ fail */
655	fe = mempool_alloc(&lc->flush_entry_pool, GFP_NOIO);
656	BUG_ON(!fe);
657
658	spin_lock_irqsave(&lc->flush_lock, flags);
659	fe->type = DM_ULOG_MARK_REGION;
660	fe->region = region;
661	list_add(&fe->list, &lc->mark_list);
662	spin_unlock_irqrestore(&lc->flush_lock, flags);
663
664	return;
665}
666
667/*
668 * userspace_clear_region
669 *
670 * This function must not block.
671 * So, the alloc can't block.  In the worst case, it is ok to
672 * fail.  It would simply mean we can't clear the region.
673 * Does nothing to current sync context, but does mean
674 * the region will be re-sync'ed on a reload of the mirror
675 * even though it is in-sync.
676 */
677static void userspace_clear_region(struct dm_dirty_log *log, region_t region)
678{
679	unsigned long flags;
680	struct log_c *lc = log->context;
681	struct dm_dirty_log_flush_entry *fe;
682
683	/*
684	 * If we fail to allocate, we skip the clearing of
685	 * the region.  This doesn't hurt us in any way, except
686	 * to cause the region to be resync'ed when the
687	 * device is activated next time.
688	 */
689	fe = mempool_alloc(&lc->flush_entry_pool, GFP_ATOMIC);
690	if (!fe) {
691		DMERR("Failed to allocate memory to clear region.");
692		return;
693	}
694
695	spin_lock_irqsave(&lc->flush_lock, flags);
696	fe->type = DM_ULOG_CLEAR_REGION;
697	fe->region = region;
698	list_add(&fe->list, &lc->clear_list);
699	spin_unlock_irqrestore(&lc->flush_lock, flags);
700
701	return;
702}
703
704/*
705 * userspace_get_resync_work
706 *
707 * Get a region that needs recovery.  It is valid to return
708 * an error for this function.
709 *
710 * Returns: 1 if region filled, 0 if no work, <0 on error
711 */
712static int userspace_get_resync_work(struct dm_dirty_log *log, region_t *region)
713{
714	int r;
715	size_t rdata_size;
716	struct log_c *lc = log->context;
717	struct {
718		int64_t i; /* 64-bit for mix arch compatibility */
719		region_t r;
720	} pkg;
721
722	if (lc->in_sync_hint >= lc->region_count)
723		return 0;
724
725	rdata_size = sizeof(pkg);
726	r = userspace_do_request(lc, lc->uuid, DM_ULOG_GET_RESYNC_WORK,
727				 NULL, 0, (char *)&pkg, &rdata_size);
728
729	*region = pkg.r;
730	return (r) ? r : (int)pkg.i;
731}
732
733/*
734 * userspace_set_region_sync
735 *
736 * Set the sync status of a given region.  This function
737 * must not fail.
738 */
739static void userspace_set_region_sync(struct dm_dirty_log *log,
740				      region_t region, int in_sync)
741{
742	struct log_c *lc = log->context;
743	struct {
744		region_t r;
745		int64_t i;
746	} pkg;
747
748	pkg.r = region;
749	pkg.i = (int64_t)in_sync;
750
751	(void) userspace_do_request(lc, lc->uuid, DM_ULOG_SET_REGION_SYNC,
752				    (char *)&pkg, sizeof(pkg), NULL, NULL);
753
754	/*
755	 * It would be nice to be able to report failures.
756	 * However, it is easy enough to detect and resolve.
757	 */
758	return;
759}
760
761/*
762 * userspace_get_sync_count
763 *
764 * If there is any sort of failure when consulting the server,
765 * we assume that the sync count is zero.
766 *
767 * Returns: sync count on success, 0 on failure
768 */
769static region_t userspace_get_sync_count(struct dm_dirty_log *log)
770{
771	int r;
772	size_t rdata_size;
773	uint64_t sync_count;
774	struct log_c *lc = log->context;
775
776	rdata_size = sizeof(sync_count);
777	r = userspace_do_request(lc, lc->uuid, DM_ULOG_GET_SYNC_COUNT,
778				 NULL, 0, (char *)&sync_count, &rdata_size);
779
780	if (r)
781		return 0;
782
783	if (sync_count >= lc->region_count)
784		lc->in_sync_hint = lc->region_count;
785
786	return (region_t)sync_count;
787}
788
789/*
790 * userspace_status
791 *
792 * Returns: amount of space consumed
793 */
794static int userspace_status(struct dm_dirty_log *log, status_type_t status_type,
795			    char *result, unsigned maxlen)
796{
797	int r = 0;
798	char *table_args;
799	size_t sz = (size_t)maxlen;
800	struct log_c *lc = log->context;
801
802	switch (status_type) {
803	case STATUSTYPE_INFO:
804		r = userspace_do_request(lc, lc->uuid, DM_ULOG_STATUS_INFO,
805					 NULL, 0, result, &sz);
806
807		if (r) {
808			sz = 0;
809			DMEMIT("%s 1 COM_FAILURE", log->type->name);
810		}
811		break;
812	case STATUSTYPE_TABLE:
813		sz = 0;
814		table_args = strchr(lc->usr_argv_str, ' ');
815		BUG_ON(!table_args); /* There will always be a ' ' */
816		table_args++;
817
818		DMEMIT("%s %u %s ", log->type->name, lc->usr_argc, lc->uuid);
819		if (lc->integrated_flush)
820			DMEMIT("integrated_flush ");
821		DMEMIT("%s ", table_args);
822		break;
 
 
 
823	}
824	return (r) ? 0 : (int)sz;
825}
826
827/*
828 * userspace_is_remote_recovering
829 *
830 * Returns: 1 if region recovering, 0 otherwise
831 */
832static int userspace_is_remote_recovering(struct dm_dirty_log *log,
833					  region_t region)
834{
835	int r;
836	uint64_t region64 = region;
837	struct log_c *lc = log->context;
838	static unsigned long limit;
839	struct {
840		int64_t is_recovering;
841		uint64_t in_sync_hint;
842	} pkg;
843	size_t rdata_size = sizeof(pkg);
844
845	/*
846	 * Once the mirror has been reported to be in-sync,
847	 * it will never again ask for recovery work.  So,
848	 * we can safely say there is not a remote machine
849	 * recovering if the device is in-sync.  (in_sync_hint
850	 * must be reset at resume time.)
851	 */
852	if (region < lc->in_sync_hint)
853		return 0;
854	else if (time_after(limit, jiffies))
855		return 1;
856
857	limit = jiffies + (HZ / 4);
858	r = userspace_do_request(lc, lc->uuid, DM_ULOG_IS_REMOTE_RECOVERING,
859				 (char *)&region64, sizeof(region64),
860				 (char *)&pkg, &rdata_size);
861	if (r)
862		return 1;
863
864	lc->in_sync_hint = pkg.in_sync_hint;
865
866	return (int)pkg.is_recovering;
867}
868
869static struct dm_dirty_log_type _userspace_type = {
870	.name = "userspace",
871	.module = THIS_MODULE,
872	.ctr = userspace_ctr,
873	.dtr = userspace_dtr,
874	.presuspend = userspace_presuspend,
875	.postsuspend = userspace_postsuspend,
876	.resume = userspace_resume,
877	.get_region_size = userspace_get_region_size,
878	.is_clean = userspace_is_clean,
879	.in_sync = userspace_in_sync,
880	.flush = userspace_flush,
881	.mark_region = userspace_mark_region,
882	.clear_region = userspace_clear_region,
883	.get_resync_work = userspace_get_resync_work,
884	.set_region_sync = userspace_set_region_sync,
885	.get_sync_count = userspace_get_sync_count,
886	.status = userspace_status,
887	.is_remote_recovering = userspace_is_remote_recovering,
888};
889
890static int __init userspace_dirty_log_init(void)
891{
892	int r = 0;
893
894	_flush_entry_cache = KMEM_CACHE(dm_dirty_log_flush_entry, 0);
895	if (!_flush_entry_cache) {
896		DMWARN("Unable to create flush_entry_cache: No memory.");
897		return -ENOMEM;
898	}
899
900	r = dm_ulog_tfr_init();
901	if (r) {
902		DMWARN("Unable to initialize userspace log communications");
903		kmem_cache_destroy(_flush_entry_cache);
904		return r;
905	}
906
907	r = dm_dirty_log_type_register(&_userspace_type);
908	if (r) {
909		DMWARN("Couldn't register userspace dirty log type");
910		dm_ulog_tfr_exit();
911		kmem_cache_destroy(_flush_entry_cache);
912		return r;
913	}
914
915	DMINFO("version " DM_LOG_USERSPACE_VSN " loaded");
916	return 0;
917}
918
919static void __exit userspace_dirty_log_exit(void)
920{
921	dm_dirty_log_type_unregister(&_userspace_type);
922	dm_ulog_tfr_exit();
923	kmem_cache_destroy(_flush_entry_cache);
924
925	DMINFO("version " DM_LOG_USERSPACE_VSN " unloaded");
926	return;
927}
928
929module_init(userspace_dirty_log_init);
930module_exit(userspace_dirty_log_exit);
931
932MODULE_DESCRIPTION(DM_NAME " userspace dirty log link");
933MODULE_AUTHOR("Jonathan Brassow <dm-devel@redhat.com>");
934MODULE_LICENSE("GPL");