1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2006-2009 Red Hat, Inc.
  4 *
  5 * This file is released under the LGPL.
  6 */
  7
  8#include <linux/bio.h>
  9#include <linux/slab.h>
 10#include <linux/jiffies.h>
 11#include <linux/dm-dirty-log.h>
 12#include <linux/device-mapper.h>
 13#include <linux/dm-log-userspace.h>
 14#include <linux/module.h>
 15#include <linux/workqueue.h>
 16
 17#include "dm-log-userspace-transfer.h"
 18
 19#define DM_LOG_USERSPACE_VSN "1.3.0"
 20
 21#define FLUSH_ENTRY_POOL_SIZE 16
 22
 23struct dm_dirty_log_flush_entry {
 24	int type;
 25	region_t region;
 26	struct list_head list;
 27};
 28
 29/*
 30 * This limit on the number of mark and clear request is, to a degree,
 31 * arbitrary.  However, there is some basis for the choice in the limits
 32 * imposed on the size of data payload by dm-log-userspace-transfer.c:
 33 * dm_consult_userspace().
 34 */
 35#define MAX_FLUSH_GROUP_COUNT 32
 36
 37struct log_c {
 38	struct dm_target *ti;
 39	struct dm_dev *log_dev;
 40
 41	char *usr_argv_str;
 42	uint32_t usr_argc;
 43
 44	uint32_t region_size;
 45	region_t region_count;
 46	uint64_t luid;
 47	char uuid[DM_UUID_LEN];
 48
 49	/*
 50	 * Mark and clear requests are held until a flush is issued
 51	 * so that we can group, and thereby limit, the amount of
 52	 * network traffic between kernel and userspace.  The 'flush_lock'
 53	 * is used to protect these lists.
 54	 */
 55	spinlock_t flush_lock;
 56	struct list_head mark_list;
 57	struct list_head clear_list;
 58
 59	/*
 60	 * in_sync_hint gets set when doing is_remote_recovering.  It
 61	 * represents the first region that needs recovery.  IOW, the
 62	 * first zero bit of sync_bits.  This can be useful for to limit
 63	 * traffic for calls like is_remote_recovering and get_resync_work,
 64	 * but be take care in its use for anything else.
 65	 */
 66	uint64_t in_sync_hint;
 67
 68	/*
 69	 * Workqueue for flush of clear region requests.
 
 
 
 70	 */
 71	struct workqueue_struct *dmlog_wq;
 72	struct delayed_work flush_log_work;
 73	atomic_t sched_flush;
 
 74
 75	/*
 76	 * Combine userspace flush and mark requests for efficiency.
 77	 */
 78	uint32_t integrated_flush;
 79
 80	mempool_t flush_entry_pool;
 81};
 
 
 82
 83static struct kmem_cache *_flush_entry_cache;
 
 
 
 84
 85static int userspace_do_request(struct log_c *lc, const char *uuid,
 86				int request_type, char *data, size_t data_size,
 87				char *rdata, size_t *rdata_size)
 88{
 89	int r;
 90
 91	/*
 92	 * If the server isn't there, -ESRCH is returned,
 93	 * and we must keep trying until the server is
 94	 * restored.
 95	 */
 96retry:
 97	r = dm_consult_userspace(uuid, lc->luid, request_type, data,
 98				 data_size, rdata, rdata_size);
 99
100	if (r != -ESRCH)
101		return r;
102
103	DMERR(" Userspace log server not found.");
104	while (1) {
105		set_current_state(TASK_INTERRUPTIBLE);
106		schedule_timeout(2*HZ);
107		DMWARN("Attempting to contact userspace log server...");
108		r = dm_consult_userspace(uuid, lc->luid, DM_ULOG_CTR,
109					 lc->usr_argv_str,
110					 strlen(lc->usr_argv_str) + 1,
111					 NULL, NULL);
112		if (!r)
113			break;
114	}
115	DMINFO("Reconnected to userspace log server... DM_ULOG_CTR complete");
116	r = dm_consult_userspace(uuid, lc->luid, DM_ULOG_RESUME, NULL,
117				 0, NULL, NULL);
118	if (!r)
119		goto retry;
120
121	DMERR("Error trying to resume userspace log: %d", r);
122
123	return -ESRCH;
124}
125
126static int build_constructor_string(struct dm_target *ti,
127				    unsigned int argc, char **argv,
128				    char **ctr_str)
129{
130	int i, str_size;
131	char *str = NULL;
132
133	*ctr_str = NULL;
134
135	/*
136	 * Determine overall size of the string.
137	 */
138	for (i = 0, str_size = 0; i < argc; i++)
139		str_size += strlen(argv[i]) + 1; /* +1 for space between args */
140
141	str_size += 20; /* Max number of chars in a printed u64 number */
142
143	str = kzalloc(str_size, GFP_KERNEL);
144	if (!str) {
145		DMWARN("Unable to allocate memory for constructor string");
146		return -ENOMEM;
147	}
148
149	str_size = sprintf(str, "%llu", (unsigned long long)ti->len);
150	for (i = 0; i < argc; i++)
151		str_size += sprintf(str + str_size, " %s", argv[i]);
152
153	*ctr_str = str;
154	return str_size;
155}
156
157static void do_flush(struct work_struct *work)
158{
159	int r;
160	struct log_c *lc = container_of(work, struct log_c, flush_log_work.work);
161
162	atomic_set(&lc->sched_flush, 0);
163
164	r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH, NULL, 0, NULL, NULL);
165
166	if (r)
167		dm_table_event(lc->ti->table);
168}
169
170/*
171 * userspace_ctr
172 *
173 * argv contains:
174 *	<UUID> [integrated_flush] <other args>
175 * Where 'other args' are the userspace implementation-specific log
176 * arguments.
177 *
178 * Example:
179 *	<UUID> [integrated_flush] clustered-disk <arg count> <log dev>
180 *	<region_size> [[no]sync]
181 *
182 * This module strips off the <UUID> and uses it for identification
183 * purposes when communicating with userspace about a log.
184 *
185 * If integrated_flush is defined, the kernel combines flush
186 * and mark requests.
187 *
188 * The rest of the line, beginning with 'clustered-disk', is passed
189 * to the userspace ctr function.
190 */
191static int userspace_ctr(struct dm_dirty_log *log, struct dm_target *ti,
192			 unsigned int argc, char **argv)
193{
194	int r = 0;
195	int str_size;
196	char *ctr_str = NULL;
197	struct log_c *lc = NULL;
198	uint64_t rdata;
199	size_t rdata_size = sizeof(rdata);
200	char *devices_rdata = NULL;
201	size_t devices_rdata_size = DM_NAME_LEN;
202
203	if (argc < 3) {
204		DMWARN("Too few arguments to userspace dirty log");
205		return -EINVAL;
206	}
207
208	lc = kzalloc(sizeof(*lc), GFP_KERNEL);
209	if (!lc) {
210		DMWARN("Unable to allocate userspace log context.");
211		return -ENOMEM;
212	}
213
214	/* The ptr value is sufficient for local unique id */
215	lc->luid = (unsigned long)lc;
216
217	lc->ti = ti;
218
219	if (strlen(argv[0]) > (DM_UUID_LEN - 1)) {
220		DMWARN("UUID argument too long.");
221		kfree(lc);
222		return -EINVAL;
223	}
224
225	lc->usr_argc = argc;
226
227	strscpy(lc->uuid, argv[0], sizeof(lc->uuid));
228	argc--;
229	argv++;
230	spin_lock_init(&lc->flush_lock);
231	INIT_LIST_HEAD(&lc->mark_list);
232	INIT_LIST_HEAD(&lc->clear_list);
233
234	if (!strcasecmp(argv[0], "integrated_flush")) {
235		lc->integrated_flush = 1;
236		argc--;
237		argv++;
238	}
239
240	str_size = build_constructor_string(ti, argc, argv, &ctr_str);
241	if (str_size < 0) {
242		kfree(lc);
243		return str_size;
244	}
245
246	devices_rdata = kzalloc(devices_rdata_size, GFP_KERNEL);
247	if (!devices_rdata) {
248		DMERR("Failed to allocate memory for device information");
249		r = -ENOMEM;
250		goto out;
251	}
252
253	r = mempool_init_slab_pool(&lc->flush_entry_pool, FLUSH_ENTRY_POOL_SIZE,
254				   _flush_entry_cache);
255	if (r) {
256		DMERR("Failed to create flush_entry_pool");
257		goto out;
258	}
259
260	/*
261	 * Send table string and get back any opened device.
262	 */
263	r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_CTR,
264				 ctr_str, str_size,
265				 devices_rdata, &devices_rdata_size);
266
267	if (r < 0) {
268		if (r == -ESRCH)
269			DMERR("Userspace log server not found");
270		else
271			DMERR("Userspace log server failed to create log");
272		goto out;
273	}
274
275	/* Since the region size does not change, get it now */
276	rdata_size = sizeof(rdata);
277	r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_GET_REGION_SIZE,
278				 NULL, 0, (char *)&rdata, &rdata_size);
279
280	if (r) {
281		DMERR("Failed to get region size of dirty log");
282		goto out;
283	}
284
285	lc->region_size = (uint32_t)rdata;
286	lc->region_count = dm_sector_div_up(ti->len, lc->region_size);
287
288	if (devices_rdata_size) {
289		if (devices_rdata[devices_rdata_size - 1] != '\0') {
290			DMERR("DM_ULOG_CTR device return string not properly terminated");
291			r = -EINVAL;
292			goto out;
293		}
294		r = dm_get_device(ti, devices_rdata,
295				  dm_table_get_mode(ti->table), &lc->log_dev);
296		if (r)
297			DMERR("Failed to register %s with device-mapper",
298			      devices_rdata);
299	}
300
301	if (lc->integrated_flush) {
302		lc->dmlog_wq = alloc_workqueue("dmlogd", WQ_MEM_RECLAIM, 0);
303		if (!lc->dmlog_wq) {
304			DMERR("couldn't start dmlogd");
305			r = -ENOMEM;
306			goto out;
307		}
308
309		INIT_DELAYED_WORK(&lc->flush_log_work, do_flush);
310		atomic_set(&lc->sched_flush, 0);
311	}
312
313out:
314	kfree(devices_rdata);
315	if (r) {
316		mempool_exit(&lc->flush_entry_pool);
317		kfree(lc);
318		kfree(ctr_str);
319	} else {
320		lc->usr_argv_str = ctr_str;
 
321		log->context = lc;
322	}
323
324	return r;
325}
326
327static void userspace_dtr(struct dm_dirty_log *log)
328{
329	struct log_c *lc = log->context;
330
331	if (lc->integrated_flush) {
332		/* flush workqueue */
333		if (atomic_read(&lc->sched_flush))
334			flush_delayed_work(&lc->flush_log_work);
335
336		destroy_workqueue(lc->dmlog_wq);
337	}
338
339	(void) dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_DTR,
340				    NULL, 0, NULL, NULL);
341
342	if (lc->log_dev)
343		dm_put_device(lc->ti, lc->log_dev);
344
345	mempool_exit(&lc->flush_entry_pool);
346
347	kfree(lc->usr_argv_str);
348	kfree(lc);
 
 
349}
350
351static int userspace_presuspend(struct dm_dirty_log *log)
352{
353	int r;
354	struct log_c *lc = log->context;
355
356	r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_PRESUSPEND,
357				 NULL, 0, NULL, NULL);
 
358
359	return r;
360}
361
362static int userspace_postsuspend(struct dm_dirty_log *log)
363{
364	int r;
365	struct log_c *lc = log->context;
366
367	/*
368	 * Run planned flush earlier.
369	 */
370	if (lc->integrated_flush && atomic_read(&lc->sched_flush))
371		flush_delayed_work(&lc->flush_log_work);
372
373	r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_POSTSUSPEND,
374				 NULL, 0, NULL, NULL);
 
375
376	return r;
377}
378
379static int userspace_resume(struct dm_dirty_log *log)
380{
381	int r;
382	struct log_c *lc = log->context;
383
384	lc->in_sync_hint = 0;
385	r = dm_consult_userspace(lc->uuid, lc->luid, DM_ULOG_RESUME,
386				 NULL, 0, NULL, NULL);
 
387
388	return r;
389}
390
391static uint32_t userspace_get_region_size(struct dm_dirty_log *log)
392{
393	struct log_c *lc = log->context;
394
395	return lc->region_size;
396}
397
398/*
399 * userspace_is_clean
400 *
401 * Check whether a region is clean.  If there is any sort of
402 * failure when consulting the server, we return not clean.
403 *
404 * Returns: 1 if clean, 0 otherwise
405 */
406static int userspace_is_clean(struct dm_dirty_log *log, region_t region)
407{
408	int r;
409	uint64_t region64 = (uint64_t)region;
410	int64_t is_clean;
411	size_t rdata_size;
412	struct log_c *lc = log->context;
413
414	rdata_size = sizeof(is_clean);
415	r = userspace_do_request(lc, lc->uuid, DM_ULOG_IS_CLEAN,
416				 (char *)&region64, sizeof(region64),
417				 (char *)&is_clean, &rdata_size);
418
419	return (r) ? 0 : (int)is_clean;
420}
421
422/*
423 * userspace_in_sync
424 *
425 * Check if the region is in-sync.  If there is any sort
426 * of failure when consulting the server, we assume that
427 * the region is not in sync.
428 *
429 * If 'can_block' is set, return immediately
430 *
431 * Returns: 1 if in-sync, 0 if not-in-sync, -EWOULDBLOCK
432 */
433static int userspace_in_sync(struct dm_dirty_log *log, region_t region,
434			     int can_block)
435{
436	int r;
437	uint64_t region64 = region;
438	int64_t in_sync;
439	size_t rdata_size;
440	struct log_c *lc = log->context;
441
442	/*
443	 * We can never respond directly - even if in_sync_hint is
444	 * set.  This is because another machine could see a device
445	 * failure and mark the region out-of-sync.  If we don't go
446	 * to userspace to ask, we might think the region is in-sync
447	 * and allow a read to pick up data that is stale.  (This is
448	 * very unlikely if a device actually fails; but it is very
449	 * likely if a connection to one device from one machine fails.)
450	 *
451	 * There still might be a problem if the mirror caches the region
452	 * state as in-sync... but then this call would not be made.  So,
453	 * that is a mirror problem.
454	 */
455	if (!can_block)
456		return -EWOULDBLOCK;
457
458	rdata_size = sizeof(in_sync);
459	r = userspace_do_request(lc, lc->uuid, DM_ULOG_IN_SYNC,
460				 (char *)&region64, sizeof(region64),
461				 (char *)&in_sync, &rdata_size);
462	return (r) ? 0 : (int)in_sync;
463}
464
465static int flush_one_by_one(struct log_c *lc, struct list_head *flush_list)
466{
467	int r = 0;
468	struct dm_dirty_log_flush_entry *fe;
469
470	list_for_each_entry(fe, flush_list, list) {
471		r = userspace_do_request(lc, lc->uuid, fe->type,
472					 (char *)&fe->region,
473					 sizeof(fe->region),
474					 NULL, NULL);
475		if (r)
476			break;
477	}
478
479	return r;
480}
481
482static int flush_by_group(struct log_c *lc, struct list_head *flush_list,
483			  int flush_with_payload)
484{
485	int r = 0;
486	int count;
487	uint32_t type = 0;
488	struct dm_dirty_log_flush_entry *fe, *tmp_fe;
489	LIST_HEAD(tmp_list);
490	uint64_t group[MAX_FLUSH_GROUP_COUNT];
491
492	/*
493	 * Group process the requests
494	 */
495	while (!list_empty(flush_list)) {
496		count = 0;
497
498		list_for_each_entry_safe(fe, tmp_fe, flush_list, list) {
499			group[count] = fe->region;
500			count++;
501
502			list_move(&fe->list, &tmp_list);
503
504			type = fe->type;
505			if (count >= MAX_FLUSH_GROUP_COUNT)
506				break;
507		}
508
509		if (flush_with_payload) {
510			r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH,
511						 (char *)(group),
512						 count * sizeof(uint64_t),
513						 NULL, NULL);
514			/*
515			 * Integrated flush failed.
516			 */
517			if (r)
518				break;
519		} else {
520			r = userspace_do_request(lc, lc->uuid, type,
521						 (char *)(group),
522						 count * sizeof(uint64_t),
523						 NULL, NULL);
524			if (r) {
525				/*
526				 * Group send failed.  Attempt one-by-one.
527				 */
528				list_splice_init(&tmp_list, flush_list);
529				r = flush_one_by_one(lc, flush_list);
530				break;
531			}
532		}
533	}
534
535	/*
536	 * Must collect flush_entrys that were successfully processed
537	 * as a group so that they will be free'd by the caller.
538	 */
539	list_splice_init(&tmp_list, flush_list);
540
541	return r;
542}
543
544/*
545 * userspace_flush
546 *
547 * This function is ok to block.
548 * The flush happens in two stages.  First, it sends all
549 * clear/mark requests that are on the list.  Then it
550 * tells the server to commit them.  This gives the
551 * server a chance to optimise the commit, instead of
552 * doing it for every request.
553 *
554 * Additionally, we could implement another thread that
555 * sends the requests up to the server - reducing the
556 * load on flush.  Then the flush would have less in
557 * the list and be responsible for the finishing commit.
558 *
559 * Returns: 0 on success, < 0 on failure
560 */
561static int userspace_flush(struct dm_dirty_log *log)
562{
563	int r = 0;
564	unsigned long flags;
565	struct log_c *lc = log->context;
566	LIST_HEAD(mark_list);
567	LIST_HEAD(clear_list);
568	int mark_list_is_empty;
569	int clear_list_is_empty;
570	struct dm_dirty_log_flush_entry *fe, *tmp_fe;
571	mempool_t *flush_entry_pool = &lc->flush_entry_pool;
572
573	spin_lock_irqsave(&lc->flush_lock, flags);
574	list_splice_init(&lc->mark_list, &mark_list);
575	list_splice_init(&lc->clear_list, &clear_list);
576	spin_unlock_irqrestore(&lc->flush_lock, flags);
577
578	mark_list_is_empty = list_empty(&mark_list);
579	clear_list_is_empty = list_empty(&clear_list);
580
581	if (mark_list_is_empty && clear_list_is_empty)
582		return 0;
583
584	r = flush_by_group(lc, &clear_list, 0);
585	if (r)
586		goto out;
587
588	if (!lc->integrated_flush) {
589		r = flush_by_group(lc, &mark_list, 0);
590		if (r)
591			goto out;
592		r = userspace_do_request(lc, lc->uuid, DM_ULOG_FLUSH,
593					 NULL, 0, NULL, NULL);
594		goto out;
595	}
596
597	/*
598	 * Send integrated flush request with mark_list as payload.
599	 */
600	r = flush_by_group(lc, &mark_list, 1);
601	if (r)
602		goto out;
603
604	if (mark_list_is_empty && !atomic_read(&lc->sched_flush)) {
605		/*
606		 * When there are only clear region requests,
607		 * we schedule a flush in the future.
608		 */
609		queue_delayed_work(lc->dmlog_wq, &lc->flush_log_work, 3 * HZ);
610		atomic_set(&lc->sched_flush, 1);
611	} else {
612		/*
613		 * Cancel pending flush because we
614		 * have already flushed in mark_region.
615		 */
616		cancel_delayed_work(&lc->flush_log_work);
617		atomic_set(&lc->sched_flush, 0);
618	}
619
620out:
621	/*
622	 * We can safely remove these entries, even after failure.
623	 * Calling code will receive an error and will know that
624	 * the log facility has failed.
625	 */
626	list_for_each_entry_safe(fe, tmp_fe, &mark_list, list) {
627		list_del(&fe->list);
628		mempool_free(fe, flush_entry_pool);
629	}
630	list_for_each_entry_safe(fe, tmp_fe, &clear_list, list) {
631		list_del(&fe->list);
632		mempool_free(fe, flush_entry_pool);
633	}
634
635	if (r)
636		dm_table_event(lc->ti->table);
637
638	return r;
639}
640
641/*
642 * userspace_mark_region
643 *
644 * This function should avoid blocking unless absolutely required.
645 * (Memory allocation is valid for blocking.)
646 */
647static void userspace_mark_region(struct dm_dirty_log *log, region_t region)
648{
649	unsigned long flags;
650	struct log_c *lc = log->context;
651	struct dm_dirty_log_flush_entry *fe;
652
653	/* Wait for an allocation, but _never_ fail */
654	fe = mempool_alloc(&lc->flush_entry_pool, GFP_NOIO);
655	BUG_ON(!fe);
656
657	spin_lock_irqsave(&lc->flush_lock, flags);
658	fe->type = DM_ULOG_MARK_REGION;
659	fe->region = region;
660	list_add(&fe->list, &lc->mark_list);
661	spin_unlock_irqrestore(&lc->flush_lock, flags);
 
 
662}
663
664/*
665 * userspace_clear_region
666 *
667 * This function must not block.
668 * So, the alloc can't block.  In the worst case, it is ok to
669 * fail.  It would simply mean we can't clear the region.
670 * Does nothing to current sync context, but does mean
671 * the region will be re-sync'ed on a reload of the mirror
672 * even though it is in-sync.
673 */
674static void userspace_clear_region(struct dm_dirty_log *log, region_t region)
675{
676	unsigned long flags;
677	struct log_c *lc = log->context;
678	struct dm_dirty_log_flush_entry *fe;
679
680	/*
681	 * If we fail to allocate, we skip the clearing of
682	 * the region.  This doesn't hurt us in any way, except
683	 * to cause the region to be resync'ed when the
684	 * device is activated next time.
685	 */
686	fe = mempool_alloc(&lc->flush_entry_pool, GFP_ATOMIC);
687	if (!fe) {
688		DMERR("Failed to allocate memory to clear region.");
689		return;
690	}
691
692	spin_lock_irqsave(&lc->flush_lock, flags);
693	fe->type = DM_ULOG_CLEAR_REGION;
694	fe->region = region;
695	list_add(&fe->list, &lc->clear_list);
696	spin_unlock_irqrestore(&lc->flush_lock, flags);
 
 
697}
698
699/*
700 * userspace_get_resync_work
701 *
702 * Get a region that needs recovery.  It is valid to return
703 * an error for this function.
704 *
705 * Returns: 1 if region filled, 0 if no work, <0 on error
706 */
707static int userspace_get_resync_work(struct dm_dirty_log *log, region_t *region)
708{
709	int r;
710	size_t rdata_size;
711	struct log_c *lc = log->context;
712	struct {
713		int64_t i; /* 64-bit for mix arch compatibility */
714		region_t r;
715	} pkg;
716
717	if (lc->in_sync_hint >= lc->region_count)
718		return 0;
719
720	rdata_size = sizeof(pkg);
721	r = userspace_do_request(lc, lc->uuid, DM_ULOG_GET_RESYNC_WORK,
722				 NULL, 0, (char *)&pkg, &rdata_size);
 
723
724	*region = pkg.r;
725	return (r) ? r : (int)pkg.i;
726}
727
728/*
729 * userspace_set_region_sync
730 *
731 * Set the sync status of a given region.  This function
732 * must not fail.
733 */
734static void userspace_set_region_sync(struct dm_dirty_log *log,
735				      region_t region, int in_sync)
736{
 
737	struct log_c *lc = log->context;
738	struct {
739		region_t r;
740		int64_t i;
741	} pkg;
742
743	pkg.r = region;
744	pkg.i = (int64_t)in_sync;
745
746	(void) userspace_do_request(lc, lc->uuid, DM_ULOG_SET_REGION_SYNC,
747				    (char *)&pkg, sizeof(pkg), NULL, NULL);
 
748
749	/*
750	 * It would be nice to be able to report failures.
751	 * However, it is easy enough to detect and resolve.
752	 */
 
753}
754
755/*
756 * userspace_get_sync_count
757 *
758 * If there is any sort of failure when consulting the server,
759 * we assume that the sync count is zero.
760 *
761 * Returns: sync count on success, 0 on failure
762 */
763static region_t userspace_get_sync_count(struct dm_dirty_log *log)
764{
765	int r;
766	size_t rdata_size;
767	uint64_t sync_count;
768	struct log_c *lc = log->context;
769
770	rdata_size = sizeof(sync_count);
771	r = userspace_do_request(lc, lc->uuid, DM_ULOG_GET_SYNC_COUNT,
772				 NULL, 0, (char *)&sync_count, &rdata_size);
 
773
774	if (r)
775		return 0;
776
777	if (sync_count >= lc->region_count)
778		lc->in_sync_hint = lc->region_count;
779
780	return (region_t)sync_count;
781}
782
783/*
784 * userspace_status
785 *
786 * Returns: amount of space consumed
787 */
788static int userspace_status(struct dm_dirty_log *log, status_type_t status_type,
789			    char *result, unsigned int maxlen)
790{
791	int r = 0;
792	char *table_args;
793	size_t sz = (size_t)maxlen;
794	struct log_c *lc = log->context;
795
796	switch (status_type) {
797	case STATUSTYPE_INFO:
798		r = userspace_do_request(lc, lc->uuid, DM_ULOG_STATUS_INFO,
799					 NULL, 0, result, &sz);
 
800
801		if (r) {
802			sz = 0;
803			DMEMIT("%s 1 COM_FAILURE", log->type->name);
804		}
805		break;
806	case STATUSTYPE_TABLE:
807		sz = 0;
808		table_args = strchr(lc->usr_argv_str, ' ');
809		BUG_ON(!table_args); /* There will always be a ' ' */
810		table_args++;
811
812		DMEMIT("%s %u %s ", log->type->name, lc->usr_argc, lc->uuid);
813		if (lc->integrated_flush)
814			DMEMIT("integrated_flush ");
815		DMEMIT("%s ", table_args);
816		break;
817	case STATUSTYPE_IMA:
818		*result = '\0';
819		break;
820	}
821	return (r) ? 0 : (int)sz;
822}
823
824/*
825 * userspace_is_remote_recovering
826 *
827 * Returns: 1 if region recovering, 0 otherwise
828 */
829static int userspace_is_remote_recovering(struct dm_dirty_log *log,
830					  region_t region)
831{
832	int r;
833	uint64_t region64 = region;
834	struct log_c *lc = log->context;
835	static unsigned long limit;
836	struct {
837		int64_t is_recovering;
838		uint64_t in_sync_hint;
839	} pkg;
840	size_t rdata_size = sizeof(pkg);
841
842	/*
843	 * Once the mirror has been reported to be in-sync,
844	 * it will never again ask for recovery work.  So,
845	 * we can safely say there is not a remote machine
846	 * recovering if the device is in-sync.  (in_sync_hint
847	 * must be reset at resume time.)
848	 */
849	if (region < lc->in_sync_hint)
850		return 0;
851	else if (time_after(limit, jiffies))
852		return 1;
853
854	limit = jiffies + (HZ / 4);
855	r = userspace_do_request(lc, lc->uuid, DM_ULOG_IS_REMOTE_RECOVERING,
856				 (char *)&region64, sizeof(region64),
857				 (char *)&pkg, &rdata_size);
858	if (r)
859		return 1;
860
861	lc->in_sync_hint = pkg.in_sync_hint;
862
863	return (int)pkg.is_recovering;
864}
865
866static struct dm_dirty_log_type _userspace_type = {
867	.name = "userspace",
868	.module = THIS_MODULE,
869	.ctr = userspace_ctr,
870	.dtr = userspace_dtr,
871	.presuspend = userspace_presuspend,
872	.postsuspend = userspace_postsuspend,
873	.resume = userspace_resume,
874	.get_region_size = userspace_get_region_size,
875	.is_clean = userspace_is_clean,
876	.in_sync = userspace_in_sync,
877	.flush = userspace_flush,
878	.mark_region = userspace_mark_region,
879	.clear_region = userspace_clear_region,
880	.get_resync_work = userspace_get_resync_work,
881	.set_region_sync = userspace_set_region_sync,
882	.get_sync_count = userspace_get_sync_count,
883	.status = userspace_status,
884	.is_remote_recovering = userspace_is_remote_recovering,
885};
886
887static int __init userspace_dirty_log_init(void)
888{
889	int r = 0;
890
891	_flush_entry_cache = KMEM_CACHE(dm_dirty_log_flush_entry, 0);
892	if (!_flush_entry_cache) {
893		DMWARN("Unable to create flush_entry_cache: No memory.");
 
 
894		return -ENOMEM;
895	}
896
897	r = dm_ulog_tfr_init();
898	if (r) {
899		DMWARN("Unable to initialize userspace log communications");
900		kmem_cache_destroy(_flush_entry_cache);
901		return r;
902	}
903
904	r = dm_dirty_log_type_register(&_userspace_type);
905	if (r) {
906		DMWARN("Couldn't register userspace dirty log type");
907		dm_ulog_tfr_exit();
908		kmem_cache_destroy(_flush_entry_cache);
909		return r;
910	}
911
912	DMINFO("version " DM_LOG_USERSPACE_VSN " loaded");
913	return 0;
914}
915
916static void __exit userspace_dirty_log_exit(void)
917{
918	dm_dirty_log_type_unregister(&_userspace_type);
919	dm_ulog_tfr_exit();
920	kmem_cache_destroy(_flush_entry_cache);
921
922	DMINFO("version " DM_LOG_USERSPACE_VSN " unloaded");
 
923}
924
925module_init(userspace_dirty_log_init);
926module_exit(userspace_dirty_log_exit);
927
928MODULE_DESCRIPTION(DM_NAME " userspace dirty log link");
929MODULE_AUTHOR("Jonathan Brassow <dm-devel@lists.linux.dev>");
930MODULE_LICENSE("GPL");