xref: /spdk/module/bdev/lvol/vbdev_lvol.c (revision bf30e09abe1667ae2769aa367cde39c550bcac00)
1 /*   SPDX-License-Identifier: BSD-3-Clause
2  *   Copyright (C) 2017 Intel Corporation.
3  *   All rights reserved.
4  *   Copyright (c) 2022-2023 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
5  */
6 
7 #include "spdk/rpc.h"
8 #include "spdk/bdev_module.h"
9 #include "spdk/log.h"
10 #include "spdk/string.h"
11 #include "spdk/uuid.h"
12 #include "spdk/blob.h"
13 
14 #include "vbdev_lvol.h"
15 
16 struct vbdev_lvol_io {
17 	struct spdk_blob_ext_io_opts ext_io_opts;
18 };
19 
20 static TAILQ_HEAD(, lvol_store_bdev) g_spdk_lvol_pairs = TAILQ_HEAD_INITIALIZER(
21 			g_spdk_lvol_pairs);
22 
23 static int vbdev_lvs_init(void);
24 static void vbdev_lvs_fini_start(void);
25 static int vbdev_lvs_get_ctx_size(void);
26 static void vbdev_lvs_examine_config(struct spdk_bdev *bdev);
27 static void vbdev_lvs_examine_disk(struct spdk_bdev *bdev);
28 static bool g_shutdown_started = false;
29 
30 static struct spdk_bdev_module g_lvol_if = {
31 	.name = "lvol",
32 	.module_init = vbdev_lvs_init,
33 	.fini_start = vbdev_lvs_fini_start,
34 	.async_fini_start = true,
35 	.examine_config = vbdev_lvs_examine_config,
36 	.examine_disk = vbdev_lvs_examine_disk,
37 	.get_ctx_size = vbdev_lvs_get_ctx_size,
38 
39 };
40 
41 SPDK_BDEV_MODULE_REGISTER(lvol, &g_lvol_if)
42 
43 static void _vbdev_lvol_destroy(struct spdk_lvol *lvol, spdk_lvol_op_complete cb_fn, void *cb_arg);
44 
45 struct lvol_store_bdev *
46 vbdev_get_lvs_bdev_by_lvs(struct spdk_lvol_store *lvs_orig)
47 {
48 	struct spdk_lvol_store *lvs = NULL;
49 	struct lvol_store_bdev *lvs_bdev = vbdev_lvol_store_first();
50 
51 	while (lvs_bdev != NULL) {
52 		lvs = lvs_bdev->lvs;
53 		if (lvs == lvs_orig) {
54 			if (lvs_bdev->removal_in_progress) {
55 				/* We do not allow access to lvs that are being unloaded or
56 				 * destroyed */
57 				SPDK_DEBUGLOG(vbdev_lvol, "lvs %s: removal in progress\n",
58 					      lvs_orig->name);
59 				return NULL;
60 			} else {
61 				return lvs_bdev;
62 			}
63 		}
64 		lvs_bdev = vbdev_lvol_store_next(lvs_bdev);
65 	}
66 
67 	return NULL;
68 }
69 
70 static int
71 _vbdev_lvol_change_bdev_alias(struct spdk_lvol *lvol, const char *new_lvol_name)
72 {
73 	struct spdk_bdev_alias *tmp;
74 	char *old_alias;
75 	char *alias;
76 	int rc;
77 	int alias_number = 0;
78 
79 	/* bdev representing lvols have only one alias,
80 	 * while we changed lvs name earlier, we have to iterate alias list to get one,
81 	 * and check if there is only one alias */
82 
83 	TAILQ_FOREACH(tmp, spdk_bdev_get_aliases(lvol->bdev), tailq) {
84 		if (++alias_number > 1) {
85 			SPDK_ERRLOG("There is more than 1 alias in bdev %s\n", lvol->bdev->name);
86 			return -EINVAL;
87 		}
88 
89 		old_alias = tmp->alias.name;
90 	}
91 
92 	if (alias_number == 0) {
93 		SPDK_ERRLOG("There are no aliases in bdev %s\n", lvol->bdev->name);
94 		return -EINVAL;
95 	}
96 
97 	alias = spdk_sprintf_alloc("%s/%s", lvol->lvol_store->name, new_lvol_name);
98 	if (alias == NULL) {
99 		SPDK_ERRLOG("Cannot alloc memory for alias\n");
100 		return -ENOMEM;
101 	}
102 
103 	rc = spdk_bdev_alias_add(lvol->bdev, alias);
104 	if (rc != 0) {
105 		SPDK_ERRLOG("cannot add alias '%s'\n", alias);
106 		free(alias);
107 		return rc;
108 	}
109 	free(alias);
110 
111 	rc = spdk_bdev_alias_del(lvol->bdev, old_alias);
112 	if (rc != 0) {
113 		SPDK_ERRLOG("cannot remove alias '%s'\n", old_alias);
114 		return rc;
115 	}
116 
117 	return 0;
118 }
119 
120 static struct lvol_store_bdev *
121 vbdev_get_lvs_bdev_by_bdev(struct spdk_bdev *bdev_orig)
122 {
123 	struct lvol_store_bdev *lvs_bdev = vbdev_lvol_store_first();
124 
125 	while (lvs_bdev != NULL) {
126 		if (lvs_bdev->bdev == bdev_orig) {
127 			if (lvs_bdev->removal_in_progress) {
128 				/* We do not allow access to lvs that are being unloaded or
129 				 * destroyed */
130 				SPDK_DEBUGLOG(vbdev_lvol, "lvs %s: removal in progress\n",
131 					      lvs_bdev->lvs->name);
132 				return NULL;
133 			} else {
134 				return lvs_bdev;
135 			}
136 		}
137 		lvs_bdev = vbdev_lvol_store_next(lvs_bdev);
138 	}
139 
140 	return NULL;
141 }
142 
143 static void
144 vbdev_lvs_hotremove_cb(struct spdk_bdev *bdev)
145 {
146 	struct lvol_store_bdev *lvs_bdev;
147 
148 	lvs_bdev = vbdev_get_lvs_bdev_by_bdev(bdev);
149 	if (lvs_bdev != NULL) {
150 		SPDK_NOTICELOG("bdev %s being removed: closing lvstore %s\n",
151 			       spdk_bdev_get_name(bdev), lvs_bdev->lvs->name);
152 		vbdev_lvs_unload(lvs_bdev->lvs, NULL, NULL);
153 	}
154 }
155 
156 static void
157 vbdev_lvs_base_bdev_event_cb(enum spdk_bdev_event_type type, struct spdk_bdev *bdev,
158 			     void *event_ctx)
159 {
160 	switch (type) {
161 	case SPDK_BDEV_EVENT_REMOVE:
162 		vbdev_lvs_hotremove_cb(bdev);
163 		break;
164 	default:
165 		SPDK_NOTICELOG("Unsupported bdev event: type %d\n", type);
166 		break;
167 	}
168 }
169 
170 static void
171 _vbdev_lvs_create_cb(void *cb_arg, struct spdk_lvol_store *lvs, int lvserrno)
172 {
173 	struct spdk_lvs_with_handle_req *req = cb_arg;
174 	struct lvol_store_bdev *lvs_bdev;
175 	struct spdk_bdev *bdev = req->base_bdev;
176 	struct spdk_bs_dev *bs_dev = req->bs_dev;
177 
178 	if (lvserrno != 0) {
179 		assert(lvs == NULL);
180 		SPDK_ERRLOG("Cannot create lvol store bdev\n");
181 		goto end;
182 	}
183 
184 	lvserrno = spdk_bs_bdev_claim(bs_dev, &g_lvol_if);
185 	if (lvserrno != 0) {
186 		SPDK_INFOLOG(vbdev_lvol, "Lvol store base bdev already claimed by another bdev\n");
187 		req->bs_dev->destroy(req->bs_dev);
188 		goto end;
189 	}
190 
191 	assert(lvs != NULL);
192 
193 	lvs_bdev = calloc(1, sizeof(*lvs_bdev));
194 	if (!lvs_bdev) {
195 		lvserrno = -ENOMEM;
196 		goto end;
197 	}
198 	lvs_bdev->lvs = lvs;
199 	lvs_bdev->bdev = bdev;
200 	lvs_bdev->req = NULL;
201 
202 	TAILQ_INSERT_TAIL(&g_spdk_lvol_pairs, lvs_bdev, lvol_stores);
203 	SPDK_INFOLOG(vbdev_lvol, "Lvol store bdev inserted\n");
204 
205 end:
206 	req->cb_fn(req->cb_arg, lvs, lvserrno);
207 	free(req);
208 
209 	return;
210 }
211 
212 int
213 vbdev_lvs_create(const char *base_bdev_name, const char *name, uint32_t cluster_sz,
214 		 enum lvs_clear_method clear_method, uint32_t num_md_pages_per_cluster_ratio,
215 		 spdk_lvs_op_with_handle_complete cb_fn, void *cb_arg)
216 {
217 	struct spdk_bs_dev *bs_dev;
218 	struct spdk_lvs_with_handle_req *lvs_req;
219 	struct spdk_lvs_opts opts;
220 	int rc;
221 	int len;
222 
223 	if (base_bdev_name == NULL) {
224 		SPDK_ERRLOG("missing base_bdev_name param\n");
225 		return -EINVAL;
226 	}
227 
228 	spdk_lvs_opts_init(&opts);
229 	if (cluster_sz != 0) {
230 		opts.cluster_sz = cluster_sz;
231 	}
232 
233 	if (clear_method != 0) {
234 		opts.clear_method = clear_method;
235 	}
236 
237 	if (num_md_pages_per_cluster_ratio != 0) {
238 		opts.num_md_pages_per_cluster_ratio = num_md_pages_per_cluster_ratio;
239 	}
240 
241 	if (name == NULL) {
242 		SPDK_ERRLOG("missing name param\n");
243 		return -EINVAL;
244 	}
245 
246 	len = strnlen(name, SPDK_LVS_NAME_MAX);
247 
248 	if (len == 0 || len == SPDK_LVS_NAME_MAX) {
249 		SPDK_ERRLOG("name must be between 1 and %d characters\n", SPDK_LVS_NAME_MAX - 1);
250 		return -EINVAL;
251 	}
252 	snprintf(opts.name, sizeof(opts.name), "%s", name);
253 	opts.esnap_bs_dev_create = vbdev_lvol_esnap_dev_create;
254 
255 	lvs_req = calloc(1, sizeof(*lvs_req));
256 	if (!lvs_req) {
257 		SPDK_ERRLOG("Cannot alloc memory for vbdev lvol store request pointer\n");
258 		return -ENOMEM;
259 	}
260 
261 	rc = spdk_bdev_create_bs_dev_ext(base_bdev_name, vbdev_lvs_base_bdev_event_cb,
262 					 NULL, &bs_dev);
263 	if (rc < 0) {
264 		SPDK_ERRLOG("Cannot create blobstore device\n");
265 		free(lvs_req);
266 		return rc;
267 	}
268 
269 	lvs_req->bs_dev = bs_dev;
270 	lvs_req->base_bdev = bs_dev->get_base_bdev(bs_dev);
271 	lvs_req->cb_fn = cb_fn;
272 	lvs_req->cb_arg = cb_arg;
273 
274 	rc = spdk_lvs_init(bs_dev, &opts, _vbdev_lvs_create_cb, lvs_req);
275 	if (rc < 0) {
276 		free(lvs_req);
277 		bs_dev->destroy(bs_dev);
278 		return rc;
279 	}
280 
281 	return 0;
282 }
283 
284 static void
285 _vbdev_lvs_rename_cb(void *cb_arg, int lvserrno)
286 {
287 	struct spdk_lvs_req *req = cb_arg;
288 	struct spdk_lvol *tmp;
289 
290 	if (lvserrno != 0) {
291 		SPDK_INFOLOG(vbdev_lvol, "Lvol store rename failed\n");
292 	} else {
293 		TAILQ_FOREACH(tmp, &req->lvol_store->lvols, link) {
294 			/* We have to pass current lvol name, since only lvs name changed */
295 			_vbdev_lvol_change_bdev_alias(tmp, tmp->name);
296 		}
297 	}
298 
299 	req->cb_fn(req->cb_arg, lvserrno);
300 	free(req);
301 }
302 
303 void
304 vbdev_lvs_rename(struct spdk_lvol_store *lvs, const char *new_lvs_name,
305 		 spdk_lvs_op_complete cb_fn, void *cb_arg)
306 {
307 	struct lvol_store_bdev *lvs_bdev;
308 
309 	struct spdk_lvs_req *req;
310 
311 	lvs_bdev = vbdev_get_lvs_bdev_by_lvs(lvs);
312 	if (!lvs_bdev) {
313 		SPDK_ERRLOG("No such lvol store found\n");
314 		cb_fn(cb_arg, -ENODEV);
315 		return;
316 	}
317 
318 	req = calloc(1, sizeof(*req));
319 	if (!req) {
320 		SPDK_ERRLOG("Cannot alloc memory for vbdev lvol store request pointer\n");
321 		cb_fn(cb_arg, -ENOMEM);
322 		return;
323 	}
324 	req->cb_fn = cb_fn;
325 	req->cb_arg = cb_arg;
326 	req->lvol_store = lvs;
327 
328 	spdk_lvs_rename(lvs, new_lvs_name, _vbdev_lvs_rename_cb, req);
329 }
330 
331 static void
332 _vbdev_lvs_remove_cb(void *cb_arg, int lvserrno)
333 {
334 	struct lvol_store_bdev *lvs_bdev = cb_arg;
335 	struct spdk_lvs_req *req = lvs_bdev->req;
336 
337 	if (lvserrno != 0) {
338 		SPDK_INFOLOG(vbdev_lvol, "Lvol store removed with error: %d.\n", lvserrno);
339 	}
340 
341 	TAILQ_REMOVE(&g_spdk_lvol_pairs, lvs_bdev, lvol_stores);
342 	free(lvs_bdev);
343 
344 	if (req->cb_fn != NULL) {
345 		req->cb_fn(req->cb_arg, lvserrno);
346 	}
347 	free(req);
348 }
349 
350 static void
351 _vbdev_lvs_remove_lvol_cb(void *cb_arg, int lvolerrno)
352 {
353 	struct lvol_store_bdev *lvs_bdev = cb_arg;
354 	struct spdk_lvol_store *lvs = lvs_bdev->lvs;
355 	struct spdk_lvol *lvol;
356 
357 	if (lvolerrno != 0) {
358 		SPDK_DEBUGLOG(vbdev_lvol, "Lvol removed with errno %d\n", lvolerrno);
359 	}
360 
361 	if (TAILQ_EMPTY(&lvs->lvols)) {
362 		spdk_lvs_destroy(lvs, _vbdev_lvs_remove_cb, lvs_bdev);
363 		return;
364 	}
365 
366 	lvol = TAILQ_FIRST(&lvs->lvols);
367 	while (lvol != NULL) {
368 		if (spdk_lvol_deletable(lvol)) {
369 			_vbdev_lvol_destroy(lvol, _vbdev_lvs_remove_lvol_cb, lvs_bdev);
370 			return;
371 		}
372 		lvol = TAILQ_NEXT(lvol, link);
373 	}
374 
375 	/* If no lvol is deletable, that means there is circular dependency. */
376 	SPDK_ERRLOG("Lvols left in lvs, but unable to delete.\n");
377 	assert(false);
378 }
379 
380 static bool
381 _vbdev_lvs_are_lvols_closed(struct spdk_lvol_store *lvs)
382 {
383 	struct spdk_lvol *lvol;
384 
385 	TAILQ_FOREACH(lvol, &lvs->lvols, link) {
386 		if (lvol->ref_count != 0) {
387 			return false;
388 		}
389 	}
390 	return true;
391 }
392 
393 static void
394 _vbdev_lvs_remove_bdev_unregistered_cb(void *cb_arg, int bdeverrno)
395 {
396 	struct lvol_store_bdev *lvs_bdev = cb_arg;
397 	struct spdk_lvol_store *lvs = lvs_bdev->lvs;
398 
399 	if (bdeverrno != 0) {
400 		SPDK_DEBUGLOG(vbdev_lvol, "Lvol unregistered with errno %d\n", bdeverrno);
401 	}
402 
403 	/* Lvol store can be unloaded once all lvols are closed. */
404 	if (_vbdev_lvs_are_lvols_closed(lvs)) {
405 		spdk_lvs_unload(lvs, _vbdev_lvs_remove_cb, lvs_bdev);
406 	}
407 }
408 
409 static void
410 _vbdev_lvs_remove(struct spdk_lvol_store *lvs, spdk_lvs_op_complete cb_fn, void *cb_arg,
411 		  bool destroy)
412 {
413 	struct spdk_lvs_req *req;
414 	struct lvol_store_bdev *lvs_bdev;
415 	struct spdk_lvol *lvol, *tmp;
416 
417 	lvs_bdev = vbdev_get_lvs_bdev_by_lvs(lvs);
418 	if (!lvs_bdev) {
419 		SPDK_ERRLOG("No such lvol store found\n");
420 		if (cb_fn != NULL) {
421 			cb_fn(cb_arg, -ENODEV);
422 		}
423 		return;
424 	}
425 
426 	req = calloc(1, sizeof(*req));
427 	if (!req) {
428 		SPDK_ERRLOG("Cannot alloc memory for vbdev lvol store request pointer\n");
429 		if (cb_fn != NULL) {
430 			cb_fn(cb_arg, -ENOMEM);
431 		}
432 		return;
433 	}
434 
435 	lvs_bdev->removal_in_progress = true;
436 
437 	req->cb_fn = cb_fn;
438 	req->cb_arg = cb_arg;
439 	lvs_bdev->req = req;
440 
441 	if (_vbdev_lvs_are_lvols_closed(lvs)) {
442 		if (destroy) {
443 			spdk_lvs_destroy(lvs, _vbdev_lvs_remove_cb, lvs_bdev);
444 			return;
445 		}
446 		spdk_lvs_unload(lvs, _vbdev_lvs_remove_cb, lvs_bdev);
447 		return;
448 	}
449 	if (destroy) {
450 		_vbdev_lvs_remove_lvol_cb(lvs_bdev, 0);
451 		return;
452 	}
453 	TAILQ_FOREACH_SAFE(lvol, &lvs->lvols, link, tmp) {
454 		if (lvol->bdev == NULL) {
455 			spdk_lvol_close(lvol, _vbdev_lvs_remove_bdev_unregistered_cb, lvs_bdev);
456 			continue;
457 		}
458 		spdk_bdev_unregister(lvol->bdev, _vbdev_lvs_remove_bdev_unregistered_cb, lvs_bdev);
459 	}
460 }
461 
462 void
463 vbdev_lvs_unload(struct spdk_lvol_store *lvs, spdk_lvs_op_complete cb_fn, void *cb_arg)
464 {
465 	_vbdev_lvs_remove(lvs, cb_fn, cb_arg, false);
466 }
467 
468 void
469 vbdev_lvs_destruct(struct spdk_lvol_store *lvs, spdk_lvs_op_complete cb_fn, void *cb_arg)
470 {
471 	_vbdev_lvs_remove(lvs, cb_fn, cb_arg, true);
472 }
473 
474 struct lvol_store_bdev *
475 vbdev_lvol_store_first(void)
476 {
477 	struct lvol_store_bdev *lvs_bdev;
478 
479 	lvs_bdev = TAILQ_FIRST(&g_spdk_lvol_pairs);
480 	if (lvs_bdev) {
481 		SPDK_INFOLOG(vbdev_lvol, "Starting lvolstore iteration at %p\n", lvs_bdev->lvs);
482 	}
483 
484 	return lvs_bdev;
485 }
486 
487 struct lvol_store_bdev *
488 vbdev_lvol_store_next(struct lvol_store_bdev *prev)
489 {
490 	struct lvol_store_bdev *lvs_bdev;
491 
492 	if (prev == NULL) {
493 		SPDK_ERRLOG("prev argument cannot be NULL\n");
494 		return NULL;
495 	}
496 
497 	lvs_bdev = TAILQ_NEXT(prev, lvol_stores);
498 	if (lvs_bdev) {
499 		SPDK_INFOLOG(vbdev_lvol, "Continuing lvolstore iteration at %p\n", lvs_bdev->lvs);
500 	}
501 
502 	return lvs_bdev;
503 }
504 
505 static struct spdk_lvol_store *
506 _vbdev_get_lvol_store_by_uuid(const struct spdk_uuid *uuid)
507 {
508 	struct spdk_lvol_store *lvs = NULL;
509 	struct lvol_store_bdev *lvs_bdev = vbdev_lvol_store_first();
510 
511 	while (lvs_bdev != NULL) {
512 		lvs = lvs_bdev->lvs;
513 		if (spdk_uuid_compare(&lvs->uuid, uuid) == 0) {
514 			return lvs;
515 		}
516 		lvs_bdev = vbdev_lvol_store_next(lvs_bdev);
517 	}
518 	return NULL;
519 }
520 
521 struct spdk_lvol_store *
522 vbdev_get_lvol_store_by_uuid(const char *uuid_str)
523 {
524 	struct spdk_uuid uuid;
525 
526 	if (spdk_uuid_parse(&uuid, uuid_str)) {
527 		return NULL;
528 	}
529 
530 	return _vbdev_get_lvol_store_by_uuid(&uuid);
531 }
532 
533 struct spdk_lvol_store *
534 vbdev_get_lvol_store_by_name(const char *name)
535 {
536 	struct spdk_lvol_store *lvs = NULL;
537 	struct lvol_store_bdev *lvs_bdev = vbdev_lvol_store_first();
538 
539 	while (lvs_bdev != NULL) {
540 		lvs = lvs_bdev->lvs;
541 		if (strncmp(lvs->name, name, sizeof(lvs->name)) == 0) {
542 			return lvs;
543 		}
544 		lvs_bdev = vbdev_lvol_store_next(lvs_bdev);
545 	}
546 	return NULL;
547 }
548 
549 struct vbdev_lvol_destroy_ctx {
550 	struct spdk_lvol *lvol;
551 	spdk_lvol_op_complete cb_fn;
552 	void *cb_arg;
553 };
554 
555 static void
556 _vbdev_lvol_unregister_unload_lvs(void *cb_arg, int lvserrno)
557 {
558 	struct lvol_bdev *lvol_bdev = cb_arg;
559 	struct lvol_store_bdev *lvs_bdev = lvol_bdev->lvs_bdev;
560 
561 	if (lvserrno != 0) {
562 		SPDK_INFOLOG(vbdev_lvol, "Lvol store removed with error: %d.\n", lvserrno);
563 	}
564 
565 	TAILQ_REMOVE(&g_spdk_lvol_pairs, lvs_bdev, lvol_stores);
566 	free(lvs_bdev);
567 
568 	spdk_bdev_destruct_done(&lvol_bdev->bdev, lvserrno);
569 	free(lvol_bdev);
570 }
571 
572 static void
573 _vbdev_lvol_unregister_cb(void *ctx, int lvolerrno)
574 {
575 	struct lvol_bdev *lvol_bdev = ctx;
576 	struct lvol_store_bdev *lvs_bdev = lvol_bdev->lvs_bdev;
577 
578 	if (g_shutdown_started && _vbdev_lvs_are_lvols_closed(lvs_bdev->lvs)) {
579 		spdk_lvs_unload(lvs_bdev->lvs, _vbdev_lvol_unregister_unload_lvs, lvol_bdev);
580 		return;
581 	}
582 
583 	spdk_bdev_destruct_done(&lvol_bdev->bdev, lvolerrno);
584 	free(lvol_bdev);
585 }
586 
587 static int
588 vbdev_lvol_unregister(void *ctx)
589 {
590 	struct spdk_lvol *lvol = ctx;
591 	struct lvol_bdev *lvol_bdev;
592 
593 	assert(lvol != NULL);
594 	lvol_bdev = SPDK_CONTAINEROF(lvol->bdev, struct lvol_bdev, bdev);
595 
596 	spdk_bdev_alias_del_all(lvol->bdev);
597 	spdk_lvol_close(lvol, _vbdev_lvol_unregister_cb, lvol_bdev);
598 
599 	/* return 1 to indicate we have an operation that must finish asynchronously before the
600 	 *  lvol is closed
601 	 */
602 	return 1;
603 }
604 
605 static void
606 _vbdev_lvol_destroy_cb(void *cb_arg, int bdeverrno)
607 {
608 	struct vbdev_lvol_destroy_ctx *ctx = cb_arg;
609 	struct spdk_lvol *lvol = ctx->lvol;
610 
611 	if (bdeverrno < 0) {
612 		SPDK_INFOLOG(vbdev_lvol, "Could not unregister bdev during lvol (%s) destroy\n",
613 			     lvol->unique_id);
614 		ctx->cb_fn(ctx->cb_arg, bdeverrno);
615 		free(ctx);
616 		return;
617 	}
618 
619 	spdk_lvol_destroy(lvol, ctx->cb_fn, ctx->cb_arg);
620 	free(ctx);
621 }
622 
623 static void
624 _vbdev_lvol_destroy(struct spdk_lvol *lvol, spdk_lvol_op_complete cb_fn, void *cb_arg)
625 {
626 	struct vbdev_lvol_destroy_ctx *ctx;
627 	size_t count;
628 
629 	assert(lvol != NULL);
630 	assert(cb_fn != NULL);
631 
632 	/* Callers other than _vbdev_lvs_remove() must ensure the lvstore is not being removed. */
633 	assert(cb_fn == _vbdev_lvs_remove_lvol_cb ||
634 	       vbdev_get_lvs_bdev_by_lvs(lvol->lvol_store) != NULL);
635 
636 	/* Check if it is possible to delete lvol */
637 	spdk_blob_get_clones(lvol->lvol_store->blobstore, lvol->blob_id, NULL, &count);
638 	if (count > 1) {
639 		/* throw an error */
640 		SPDK_ERRLOG("Cannot delete lvol\n");
641 		cb_fn(cb_arg, -EPERM);
642 		return;
643 	}
644 
645 	ctx = calloc(1, sizeof(*ctx));
646 	if (!ctx) {
647 		cb_fn(cb_arg, -ENOMEM);
648 		return;
649 	}
650 
651 	ctx->lvol = lvol;
652 	ctx->cb_fn = cb_fn;
653 	ctx->cb_arg = cb_arg;
654 
655 	if (spdk_lvol_is_degraded(lvol)) {
656 		spdk_lvol_close(lvol, _vbdev_lvol_destroy_cb, ctx);
657 		return;
658 	}
659 
660 	spdk_bdev_unregister(lvol->bdev, _vbdev_lvol_destroy_cb, ctx);
661 }
662 
663 void
664 vbdev_lvol_destroy(struct spdk_lvol *lvol, spdk_lvol_op_complete cb_fn, void *cb_arg)
665 {
666 	struct lvol_store_bdev *lvs_bdev;
667 
668 	/*
669 	 * During destruction of an lvolstore, _vbdev_lvs_unload() iterates through lvols until they
670 	 * are all deleted. There may be some IO required
671 	 */
672 	lvs_bdev = vbdev_get_lvs_bdev_by_lvs(lvol->lvol_store);
673 	if (lvs_bdev == NULL) {
674 		SPDK_DEBUGLOG(vbdev_lvol, "lvol %s: lvolstore is being removed\n",
675 			      lvol->unique_id);
676 		cb_fn(cb_arg, -ENODEV);
677 		return;
678 	}
679 
680 	_vbdev_lvol_destroy(lvol, cb_fn, cb_arg);
681 }
682 
683 static char *
684 vbdev_lvol_find_name(struct spdk_lvol *lvol, spdk_blob_id blob_id)
685 {
686 	struct spdk_lvol_store *lvs;
687 	struct spdk_lvol *_lvol;
688 
689 	assert(lvol != NULL);
690 
691 	lvs = lvol->lvol_store;
692 
693 	assert(lvs);
694 
695 	TAILQ_FOREACH(_lvol, &lvs->lvols, link) {
696 		if (_lvol->blob_id == blob_id) {
697 			return _lvol->name;
698 		}
699 	}
700 
701 	return NULL;
702 }
703 
704 static int
705 vbdev_lvol_dump_info_json(void *ctx, struct spdk_json_write_ctx *w)
706 {
707 	struct spdk_lvol *lvol = ctx;
708 	struct lvol_store_bdev *lvs_bdev;
709 	struct spdk_bdev *bdev;
710 	struct spdk_blob *blob;
711 	spdk_blob_id *ids = NULL;
712 	size_t count, i;
713 	char *name;
714 	int rc = 0;
715 
716 	spdk_json_write_named_object_begin(w, "lvol");
717 
718 	lvs_bdev = vbdev_get_lvs_bdev_by_lvs(lvol->lvol_store);
719 	if (!lvs_bdev) {
720 		SPDK_ERRLOG("No such lvol store found\n");
721 		rc = -ENODEV;
722 		goto end;
723 	}
724 
725 	bdev = lvs_bdev->bdev;
726 
727 	spdk_json_write_named_uuid(w, "lvol_store_uuid", &lvol->lvol_store->uuid);
728 
729 	spdk_json_write_named_string(w, "base_bdev", spdk_bdev_get_name(bdev));
730 
731 	blob = lvol->blob;
732 
733 	spdk_json_write_named_bool(w, "thin_provision", spdk_blob_is_thin_provisioned(blob));
734 
735 	spdk_json_write_named_uint64(w, "num_allocated_clusters",
736 				     spdk_blob_get_num_allocated_clusters(blob));
737 
738 	spdk_json_write_named_bool(w, "snapshot", spdk_blob_is_snapshot(blob));
739 
740 	spdk_json_write_named_bool(w, "clone", spdk_blob_is_clone(blob));
741 
742 	if (spdk_blob_is_clone(blob)) {
743 		spdk_blob_id snapshotid = spdk_blob_get_parent_snapshot(lvol->lvol_store->blobstore, lvol->blob_id);
744 		if (snapshotid != SPDK_BLOBID_INVALID) {
745 			name = vbdev_lvol_find_name(lvol, snapshotid);
746 			if (name != NULL) {
747 				spdk_json_write_named_string(w, "base_snapshot", name);
748 			} else {
749 				SPDK_ERRLOG("Cannot obtain snapshots name\n");
750 			}
751 		}
752 	}
753 
754 	if (spdk_blob_is_snapshot(blob)) {
755 		/* Take a number of clones */
756 		rc = spdk_blob_get_clones(lvol->lvol_store->blobstore, lvol->blob_id, NULL, &count);
757 		if (rc == -ENOMEM && count > 0) {
758 			ids = malloc(sizeof(spdk_blob_id) * count);
759 			if (ids == NULL) {
760 				SPDK_ERRLOG("Cannot allocate memory\n");
761 				rc = -ENOMEM;
762 				goto end;
763 			}
764 
765 			rc = spdk_blob_get_clones(lvol->lvol_store->blobstore, lvol->blob_id, ids, &count);
766 			if (rc == 0) {
767 				spdk_json_write_named_array_begin(w, "clones");
768 				for (i = 0; i < count; i++) {
769 					name = vbdev_lvol_find_name(lvol, ids[i]);
770 					if (name != NULL) {
771 						spdk_json_write_string(w, name);
772 					} else {
773 						SPDK_ERRLOG("Cannot obtain clone name\n");
774 					}
775 
776 				}
777 				spdk_json_write_array_end(w);
778 			}
779 			free(ids);
780 		}
781 
782 	}
783 
784 	spdk_json_write_named_bool(w, "esnap_clone", spdk_blob_is_esnap_clone(blob));
785 
786 	if (spdk_blob_is_esnap_clone(blob)) {
787 		const char *name;
788 		size_t name_len;
789 
790 		rc = spdk_blob_get_esnap_id(blob, (const void **)&name, &name_len);
791 		if (rc == 0 && name != NULL && strnlen(name, name_len) + 1 == name_len) {
792 			spdk_json_write_named_string(w, "external_snapshot_name", name);
793 		}
794 	}
795 
796 end:
797 	spdk_json_write_object_end(w);
798 
799 	return rc;
800 }
801 
802 static void
803 vbdev_lvol_write_config_json(struct spdk_bdev *bdev, struct spdk_json_write_ctx *w)
804 {
805 	/* Nothing to dump as lvol configuration is saved on physical device. */
806 }
807 
808 static struct spdk_io_channel *
809 vbdev_lvol_get_io_channel(void *ctx)
810 {
811 	struct spdk_lvol *lvol = ctx;
812 
813 	return spdk_lvol_get_io_channel(lvol);
814 }
815 
816 static bool
817 vbdev_lvol_io_type_supported(void *ctx, enum spdk_bdev_io_type io_type)
818 {
819 	struct spdk_lvol *lvol = ctx;
820 
821 	switch (io_type) {
822 	case SPDK_BDEV_IO_TYPE_WRITE:
823 	case SPDK_BDEV_IO_TYPE_UNMAP:
824 	case SPDK_BDEV_IO_TYPE_WRITE_ZEROES:
825 		return !spdk_blob_is_read_only(lvol->blob);
826 	case SPDK_BDEV_IO_TYPE_RESET:
827 	case SPDK_BDEV_IO_TYPE_READ:
828 	case SPDK_BDEV_IO_TYPE_SEEK_DATA:
829 	case SPDK_BDEV_IO_TYPE_SEEK_HOLE:
830 		return true;
831 	default:
832 		return false;
833 	}
834 }
835 
836 static void
837 lvol_op_comp(void *cb_arg, int bserrno)
838 {
839 	struct spdk_bdev_io *bdev_io = cb_arg;
840 	enum spdk_bdev_io_status status = SPDK_BDEV_IO_STATUS_SUCCESS;
841 
842 	if (bserrno != 0) {
843 		if (bserrno == -ENOMEM) {
844 			status = SPDK_BDEV_IO_STATUS_NOMEM;
845 		} else {
846 			status = SPDK_BDEV_IO_STATUS_FAILED;
847 		}
848 	}
849 
850 	spdk_bdev_io_complete(bdev_io, status);
851 }
852 
853 static void
854 lvol_unmap(struct spdk_lvol *lvol, struct spdk_io_channel *ch, struct spdk_bdev_io *bdev_io)
855 {
856 	uint64_t start_page, num_pages;
857 	struct spdk_blob *blob = lvol->blob;
858 
859 	start_page = bdev_io->u.bdev.offset_blocks;
860 	num_pages = bdev_io->u.bdev.num_blocks;
861 
862 	spdk_blob_io_unmap(blob, ch, start_page, num_pages, lvol_op_comp, bdev_io);
863 }
864 
865 static void
866 lvol_seek_data(struct spdk_lvol *lvol, struct spdk_bdev_io *bdev_io)
867 {
868 	bdev_io->u.bdev.seek.offset = spdk_blob_get_next_allocated_io_unit(lvol->blob,
869 				      bdev_io->u.bdev.offset_blocks);
870 
871 	spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_SUCCESS);
872 }
873 
874 static void
875 lvol_seek_hole(struct spdk_lvol *lvol, struct spdk_bdev_io *bdev_io)
876 {
877 	bdev_io->u.bdev.seek.offset = spdk_blob_get_next_unallocated_io_unit(lvol->blob,
878 				      bdev_io->u.bdev.offset_blocks);
879 
880 	spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_SUCCESS);
881 }
882 
883 static void
884 lvol_write_zeroes(struct spdk_lvol *lvol, struct spdk_io_channel *ch, struct spdk_bdev_io *bdev_io)
885 {
886 	uint64_t start_page, num_pages;
887 	struct spdk_blob *blob = lvol->blob;
888 
889 	start_page = bdev_io->u.bdev.offset_blocks;
890 	num_pages = bdev_io->u.bdev.num_blocks;
891 
892 	spdk_blob_io_write_zeroes(blob, ch, start_page, num_pages, lvol_op_comp, bdev_io);
893 }
894 
895 static void
896 lvol_read(struct spdk_io_channel *ch, struct spdk_bdev_io *bdev_io)
897 {
898 	uint64_t start_page, num_pages;
899 	struct spdk_lvol *lvol = bdev_io->bdev->ctxt;
900 	struct spdk_blob *blob = lvol->blob;
901 	struct vbdev_lvol_io *lvol_io = (struct vbdev_lvol_io *)bdev_io->driver_ctx;
902 
903 	start_page = bdev_io->u.bdev.offset_blocks;
904 	num_pages = bdev_io->u.bdev.num_blocks;
905 
906 	lvol_io->ext_io_opts.size = sizeof(lvol_io->ext_io_opts);
907 	lvol_io->ext_io_opts.memory_domain = bdev_io->u.bdev.memory_domain;
908 	lvol_io->ext_io_opts.memory_domain_ctx = bdev_io->u.bdev.memory_domain_ctx;
909 
910 	spdk_blob_io_readv_ext(blob, ch, bdev_io->u.bdev.iovs, bdev_io->u.bdev.iovcnt, start_page,
911 			       num_pages, lvol_op_comp, bdev_io, &lvol_io->ext_io_opts);
912 }
913 
914 static void
915 lvol_write(struct spdk_lvol *lvol, struct spdk_io_channel *ch, struct spdk_bdev_io *bdev_io)
916 {
917 	uint64_t start_page, num_pages;
918 	struct spdk_blob *blob = lvol->blob;
919 	struct vbdev_lvol_io *lvol_io = (struct vbdev_lvol_io *)bdev_io->driver_ctx;
920 
921 	start_page = bdev_io->u.bdev.offset_blocks;
922 	num_pages = bdev_io->u.bdev.num_blocks;
923 
924 	lvol_io->ext_io_opts.size = sizeof(lvol_io->ext_io_opts);
925 	lvol_io->ext_io_opts.memory_domain = bdev_io->u.bdev.memory_domain;
926 	lvol_io->ext_io_opts.memory_domain_ctx = bdev_io->u.bdev.memory_domain_ctx;
927 
928 	spdk_blob_io_writev_ext(blob, ch, bdev_io->u.bdev.iovs, bdev_io->u.bdev.iovcnt, start_page,
929 				num_pages, lvol_op_comp, bdev_io, &lvol_io->ext_io_opts);
930 }
931 
932 static int
933 lvol_reset(struct spdk_bdev_io *bdev_io)
934 {
935 	spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_FAILED);
936 
937 	return 0;
938 }
939 
940 static void
941 lvol_get_buf_cb(struct spdk_io_channel *ch, struct spdk_bdev_io *bdev_io, bool success)
942 {
943 	if (!success) {
944 		spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_FAILED);
945 		return;
946 	}
947 
948 	lvol_read(ch, bdev_io);
949 }
950 
951 static void
952 vbdev_lvol_submit_request(struct spdk_io_channel *ch, struct spdk_bdev_io *bdev_io)
953 {
954 	struct spdk_lvol *lvol = bdev_io->bdev->ctxt;
955 
956 	switch (bdev_io->type) {
957 	case SPDK_BDEV_IO_TYPE_READ:
958 		spdk_bdev_io_get_buf(bdev_io, lvol_get_buf_cb,
959 				     bdev_io->u.bdev.num_blocks * bdev_io->bdev->blocklen);
960 		break;
961 	case SPDK_BDEV_IO_TYPE_WRITE:
962 		lvol_write(lvol, ch, bdev_io);
963 		break;
964 	case SPDK_BDEV_IO_TYPE_RESET:
965 		lvol_reset(bdev_io);
966 		break;
967 	case SPDK_BDEV_IO_TYPE_UNMAP:
968 		lvol_unmap(lvol, ch, bdev_io);
969 		break;
970 	case SPDK_BDEV_IO_TYPE_WRITE_ZEROES:
971 		lvol_write_zeroes(lvol, ch, bdev_io);
972 		break;
973 	case SPDK_BDEV_IO_TYPE_SEEK_DATA:
974 		lvol_seek_data(lvol, bdev_io);
975 		break;
976 	case SPDK_BDEV_IO_TYPE_SEEK_HOLE:
977 		lvol_seek_hole(lvol, bdev_io);
978 		break;
979 	default:
980 		SPDK_INFOLOG(vbdev_lvol, "lvol: unsupported I/O type %d\n", bdev_io->type);
981 		spdk_bdev_io_complete(bdev_io, SPDK_BDEV_IO_STATUS_FAILED);
982 		return;
983 	}
984 	return;
985 }
986 
987 static int
988 vbdev_lvol_get_memory_domains(void *ctx, struct spdk_memory_domain **domains, int array_size)
989 {
990 	struct spdk_lvol *lvol = ctx;
991 	struct spdk_bdev *base_bdev, *esnap_bdev;
992 	struct spdk_bs_dev *bs_dev;
993 	struct spdk_lvol_store *lvs;
994 	int base_cnt, esnap_cnt;
995 
996 	lvs = lvol->lvol_store;
997 	base_bdev = lvs->bs_dev->get_base_bdev(lvol->lvol_store->bs_dev);
998 
999 	base_cnt = spdk_bdev_get_memory_domains(base_bdev, domains, array_size);
1000 	if (base_cnt < 0) {
1001 		return base_cnt;
1002 	}
1003 
1004 	if (lvol->blob == NULL) {
1005 		/*
1006 		 * This is probably called due to an open happening during blobstore load. Another
1007 		 * open will follow shortly that has lvol->blob set.
1008 		 */
1009 		return -EAGAIN;
1010 	}
1011 
1012 	if (!spdk_blob_is_esnap_clone(lvol->blob)) {
1013 		return base_cnt;
1014 	}
1015 
1016 	bs_dev = spdk_blob_get_esnap_bs_dev(lvol->blob);
1017 	if (bs_dev == NULL) {
1018 		assert(false);
1019 		SPDK_ERRLOG("lvol %s is an esnap clone but has no esnap device\n", lvol->unique_id);
1020 		return base_cnt;
1021 	}
1022 
1023 	if (bs_dev->get_base_bdev == NULL) {
1024 		/*
1025 		 * If this were a blob_bdev, we wouldn't be here. We are probably here because an
1026 		 * lvol bdev is being registered with spdk_bdev_register() before the external
1027 		 * snapshot bdev is loaded. Ideally, the load of a missing esnap would trigger an
1028 		 * event that causes the lvol bdev's memory domain information to be updated.
1029 		 */
1030 		return base_cnt;
1031 	}
1032 
1033 	esnap_bdev = bs_dev->get_base_bdev(bs_dev);
1034 	if (esnap_bdev == NULL) {
1035 		/*
1036 		 * The esnap bdev has not yet been loaded. Anyone that has opened at this point may
1037 		 * miss out on using memory domains if base_cnt is zero.
1038 		 */
1039 		SPDK_NOTICELOG("lvol %s reporting %d memory domains, not including missing esnap\n",
1040 			       lvol->unique_id, base_cnt);
1041 		return base_cnt;
1042 	}
1043 
1044 	if (base_cnt < array_size) {
1045 		array_size -= base_cnt;
1046 		domains += base_cnt;
1047 	} else {
1048 		array_size = 0;
1049 		domains = NULL;
1050 	}
1051 
1052 	esnap_cnt = spdk_bdev_get_memory_domains(esnap_bdev, domains, array_size);
1053 	if (esnap_cnt <= 0) {
1054 		return base_cnt;
1055 	}
1056 
1057 	return base_cnt + esnap_cnt;
1058 }
1059 
1060 static struct spdk_bdev_fn_table vbdev_lvol_fn_table = {
1061 	.destruct		= vbdev_lvol_unregister,
1062 	.io_type_supported	= vbdev_lvol_io_type_supported,
1063 	.submit_request		= vbdev_lvol_submit_request,
1064 	.get_io_channel		= vbdev_lvol_get_io_channel,
1065 	.dump_info_json		= vbdev_lvol_dump_info_json,
1066 	.write_config_json	= vbdev_lvol_write_config_json,
1067 	.get_memory_domains	= vbdev_lvol_get_memory_domains,
1068 };
1069 
1070 static void
1071 lvol_destroy_cb(void *cb_arg, int bdeverrno)
1072 {
1073 }
1074 
1075 static void
1076 _create_lvol_disk_destroy_cb(void *cb_arg, int bdeverrno)
1077 {
1078 	struct spdk_lvol *lvol = cb_arg;
1079 
1080 	if (bdeverrno < 0) {
1081 		SPDK_ERRLOG("Could not unregister bdev for lvol %s\n",
1082 			    lvol->unique_id);
1083 		return;
1084 	}
1085 
1086 	spdk_lvol_destroy(lvol, lvol_destroy_cb, NULL);
1087 }
1088 
1089 static void
1090 _create_lvol_disk_unload_cb(void *cb_arg, int bdeverrno)
1091 {
1092 	struct spdk_lvol *lvol = cb_arg;
1093 
1094 	if (bdeverrno < 0) {
1095 		SPDK_ERRLOG("Could not unregister bdev for lvol %s\n",
1096 			    lvol->unique_id);
1097 		return;
1098 	}
1099 
1100 	TAILQ_REMOVE(&lvol->lvol_store->lvols, lvol, link);
1101 	free(lvol);
1102 }
1103 
1104 static int
1105 _create_lvol_disk(struct spdk_lvol *lvol, bool destroy)
1106 {
1107 	struct spdk_bdev *bdev;
1108 	struct lvol_bdev *lvol_bdev;
1109 	struct lvol_store_bdev *lvs_bdev;
1110 	uint64_t total_size;
1111 	unsigned char *alias;
1112 	int rc;
1113 
1114 	if (spdk_lvol_is_degraded(lvol)) {
1115 		SPDK_NOTICELOG("lvol %s: blob is degraded: deferring bdev creation\n",
1116 			       lvol->unique_id);
1117 		return 0;
1118 	}
1119 
1120 	lvs_bdev = vbdev_get_lvs_bdev_by_lvs(lvol->lvol_store);
1121 	if (lvs_bdev == NULL) {
1122 		SPDK_ERRLOG("No spdk lvs-bdev pair found for lvol %s\n", lvol->unique_id);
1123 		assert(false);
1124 		return -ENODEV;
1125 	}
1126 
1127 	lvol_bdev = calloc(1, sizeof(struct lvol_bdev));
1128 	if (!lvol_bdev) {
1129 		SPDK_ERRLOG("Cannot alloc memory for lvol bdev\n");
1130 		return -ENOMEM;
1131 	}
1132 
1133 	lvol_bdev->lvol = lvol;
1134 	lvol_bdev->lvs_bdev = lvs_bdev;
1135 
1136 	bdev = &lvol_bdev->bdev;
1137 	bdev->name = lvol->unique_id;
1138 	bdev->product_name = "Logical Volume";
1139 	bdev->blocklen = spdk_bs_get_io_unit_size(lvol->lvol_store->blobstore);
1140 	total_size = spdk_blob_get_num_clusters(lvol->blob) *
1141 		     spdk_bs_get_cluster_size(lvol->lvol_store->blobstore);
1142 	assert((total_size % bdev->blocklen) == 0);
1143 	bdev->blockcnt = total_size / bdev->blocklen;
1144 	bdev->uuid = lvol->uuid;
1145 	bdev->required_alignment = lvs_bdev->bdev->required_alignment;
1146 	bdev->split_on_optimal_io_boundary = true;
1147 	bdev->optimal_io_boundary = spdk_bs_get_cluster_size(lvol->lvol_store->blobstore) / bdev->blocklen;
1148 
1149 	bdev->ctxt = lvol;
1150 	bdev->fn_table = &vbdev_lvol_fn_table;
1151 	bdev->module = &g_lvol_if;
1152 
1153 	/* Set default bdev reset waiting time. This value indicates how much
1154 	 * time a reset should wait before forcing a reset down to the underlying
1155 	 * bdev module.
1156 	 * Setting this parameter is mainly to avoid "empty" resets to a shared
1157 	 * bdev that may be used by multiple lvols. */
1158 	bdev->reset_io_drain_timeout = SPDK_BDEV_RESET_IO_DRAIN_RECOMMENDED_VALUE;
1159 
1160 	rc = spdk_bdev_register(bdev);
1161 	if (rc) {
1162 		free(lvol_bdev);
1163 		return rc;
1164 	}
1165 	lvol->bdev = bdev;
1166 
1167 	alias = spdk_sprintf_alloc("%s/%s", lvs_bdev->lvs->name, lvol->name);
1168 	if (alias == NULL) {
1169 		SPDK_ERRLOG("Cannot alloc memory for alias\n");
1170 		spdk_bdev_unregister(lvol->bdev, (destroy ? _create_lvol_disk_destroy_cb :
1171 						  _create_lvol_disk_unload_cb), lvol);
1172 		return -ENOMEM;
1173 	}
1174 
1175 	rc = spdk_bdev_alias_add(bdev, alias);
1176 	if (rc != 0) {
1177 		SPDK_ERRLOG("Cannot add alias to lvol bdev\n");
1178 		spdk_bdev_unregister(lvol->bdev, (destroy ? _create_lvol_disk_destroy_cb :
1179 						  _create_lvol_disk_unload_cb), lvol);
1180 	}
1181 	free(alias);
1182 
1183 	return rc;
1184 }
1185 
1186 static void
1187 _vbdev_lvol_create_cb(void *cb_arg, struct spdk_lvol *lvol, int lvolerrno)
1188 {
1189 	struct spdk_lvol_with_handle_req *req = cb_arg;
1190 
1191 	if (lvolerrno < 0) {
1192 		goto end;
1193 	}
1194 
1195 	lvolerrno = _create_lvol_disk(lvol, true);
1196 
1197 end:
1198 	req->cb_fn(req->cb_arg, lvol, lvolerrno);
1199 	free(req);
1200 }
1201 
1202 int
1203 vbdev_lvol_create(struct spdk_lvol_store *lvs, const char *name, uint64_t sz,
1204 		  bool thin_provision, enum lvol_clear_method clear_method, spdk_lvol_op_with_handle_complete cb_fn,
1205 		  void *cb_arg)
1206 {
1207 	struct spdk_lvol_with_handle_req *req;
1208 	int rc;
1209 
1210 	req = calloc(1, sizeof(*req));
1211 	if (req == NULL) {
1212 		return -ENOMEM;
1213 	}
1214 	req->cb_fn = cb_fn;
1215 	req->cb_arg = cb_arg;
1216 
1217 	rc = spdk_lvol_create(lvs, name, sz, thin_provision, clear_method,
1218 			      _vbdev_lvol_create_cb, req);
1219 	if (rc != 0) {
1220 		free(req);
1221 	}
1222 
1223 	return rc;
1224 }
1225 
1226 void
1227 vbdev_lvol_create_snapshot(struct spdk_lvol *lvol, const char *snapshot_name,
1228 			   spdk_lvol_op_with_handle_complete cb_fn, void *cb_arg)
1229 {
1230 	struct spdk_lvol_with_handle_req *req;
1231 
1232 	req = calloc(1, sizeof(*req));
1233 	if (req == NULL) {
1234 		cb_fn(cb_arg, NULL, -ENOMEM);
1235 		return;
1236 	}
1237 
1238 	req->cb_fn = cb_fn;
1239 	req->cb_arg = cb_arg;
1240 
1241 	spdk_lvol_create_snapshot(lvol, snapshot_name, _vbdev_lvol_create_cb, req);
1242 }
1243 
1244 void
1245 vbdev_lvol_create_clone(struct spdk_lvol *lvol, const char *clone_name,
1246 			spdk_lvol_op_with_handle_complete cb_fn, void *cb_arg)
1247 {
1248 	struct spdk_lvol_with_handle_req *req;
1249 
1250 	req = calloc(1, sizeof(*req));
1251 	if (req == NULL) {
1252 		cb_fn(cb_arg, NULL, -ENOMEM);
1253 		return;
1254 	}
1255 
1256 	req->cb_fn = cb_fn;
1257 	req->cb_arg = cb_arg;
1258 
1259 	spdk_lvol_create_clone(lvol, clone_name, _vbdev_lvol_create_cb, req);
1260 }
1261 
1262 static void
1263 ignore_bdev_event_cb(enum spdk_bdev_event_type type, struct spdk_bdev *bdev, void *ctx)
1264 {
1265 }
1266 
1267 void
1268 vbdev_lvol_create_bdev_clone(const char *esnap_name,
1269 			     struct spdk_lvol_store *lvs, const char *clone_name,
1270 			     spdk_lvol_op_with_handle_complete cb_fn, void *cb_arg)
1271 {
1272 	struct spdk_lvol_with_handle_req *req;
1273 	struct spdk_bdev_desc *desc;
1274 	struct spdk_bdev *bdev;
1275 	char bdev_uuid[SPDK_UUID_STRING_LEN];
1276 	uint64_t sz;
1277 	int rc;
1278 
1279 	if (lvs == NULL) {
1280 		SPDK_ERRLOG("lvol store not specified\n");
1281 		cb_fn(cb_arg, NULL, -EINVAL);
1282 		return;
1283 	}
1284 
1285 	rc = spdk_bdev_open_ext(esnap_name, false, ignore_bdev_event_cb, NULL, &desc);
1286 	if (rc != 0) {
1287 		SPDK_ERRLOG("bdev '%s' could not be opened: error %d\n", esnap_name, rc);
1288 		cb_fn(cb_arg, NULL, rc);
1289 		return;
1290 	}
1291 	bdev = spdk_bdev_desc_get_bdev(desc);
1292 
1293 	rc = spdk_uuid_fmt_lower(bdev_uuid, sizeof(bdev_uuid), spdk_bdev_get_uuid(bdev));
1294 	if (rc != 0) {
1295 		spdk_bdev_close(desc);
1296 		SPDK_ERRLOG("bdev %s: unable to parse UUID\n", esnap_name);
1297 		assert(false);
1298 		cb_fn(cb_arg, NULL, -ENODEV);
1299 		return;
1300 	}
1301 
1302 	req = calloc(1, sizeof(*req));
1303 	if (req == NULL) {
1304 		spdk_bdev_close(desc);
1305 		cb_fn(cb_arg, NULL, -ENOMEM);
1306 		return;
1307 	}
1308 
1309 	req->cb_fn = cb_fn;
1310 	req->cb_arg = cb_arg;
1311 
1312 	sz = spdk_bdev_get_num_blocks(bdev) * spdk_bdev_get_block_size(bdev);
1313 	rc = spdk_lvol_create_esnap_clone(bdev_uuid, sizeof(bdev_uuid), sz, lvs, clone_name,
1314 					  _vbdev_lvol_create_cb, req);
1315 	spdk_bdev_close(desc);
1316 	if (rc != 0) {
1317 		cb_fn(cb_arg, NULL, rc);
1318 		free(req);
1319 	}
1320 }
1321 
1322 static void
1323 _vbdev_lvol_rename_cb(void *cb_arg, int lvolerrno)
1324 {
1325 	struct spdk_lvol_req *req = cb_arg;
1326 
1327 	if (lvolerrno != 0) {
1328 		SPDK_ERRLOG("Renaming lvol failed\n");
1329 	}
1330 
1331 	req->cb_fn(req->cb_arg, lvolerrno);
1332 	free(req);
1333 }
1334 
1335 void
1336 vbdev_lvol_rename(struct spdk_lvol *lvol, const char *new_lvol_name,
1337 		  spdk_lvol_op_complete cb_fn, void *cb_arg)
1338 {
1339 	struct spdk_lvol_req *req;
1340 	int rc;
1341 
1342 	rc = _vbdev_lvol_change_bdev_alias(lvol, new_lvol_name);
1343 	if (rc != 0) {
1344 		SPDK_ERRLOG("renaming lvol to '%s' does not succeed\n", new_lvol_name);
1345 		cb_fn(cb_arg, rc);
1346 		return;
1347 	}
1348 
1349 	req = calloc(1, sizeof(*req));
1350 	if (req == NULL) {
1351 		cb_fn(cb_arg, -ENOMEM);
1352 		return;
1353 	}
1354 	req->cb_fn = cb_fn;
1355 	req->cb_arg = cb_arg;
1356 
1357 	spdk_lvol_rename(lvol, new_lvol_name, _vbdev_lvol_rename_cb, req);
1358 }
1359 
1360 static void
1361 _vbdev_lvol_resize_cb(void *cb_arg, int lvolerrno)
1362 {
1363 	struct spdk_lvol_req *req = cb_arg;
1364 	struct spdk_lvol *lvol = req->lvol;
1365 	uint64_t total_size;
1366 
1367 	/* change bdev size */
1368 	if (lvolerrno != 0) {
1369 		SPDK_ERRLOG("CB function for bdev lvol %s receive error no: %d.\n", lvol->name, lvolerrno);
1370 		goto finish;
1371 	}
1372 
1373 	total_size = spdk_blob_get_num_clusters(lvol->blob) *
1374 		     spdk_bs_get_cluster_size(lvol->lvol_store->blobstore);
1375 	assert((total_size % lvol->bdev->blocklen) == 0);
1376 
1377 	lvolerrno = spdk_bdev_notify_blockcnt_change(lvol->bdev, total_size / lvol->bdev->blocklen);
1378 	if (lvolerrno != 0) {
1379 		SPDK_ERRLOG("Could not change num blocks for bdev lvol %s with error no: %d.\n",
1380 			    lvol->name, lvolerrno);
1381 	}
1382 
1383 finish:
1384 	req->cb_fn(req->cb_arg, lvolerrno);
1385 	free(req);
1386 }
1387 
1388 void
1389 vbdev_lvol_resize(struct spdk_lvol *lvol, uint64_t sz, spdk_lvol_op_complete cb_fn, void *cb_arg)
1390 {
1391 	struct spdk_lvol_req *req;
1392 
1393 	if (lvol == NULL) {
1394 		SPDK_ERRLOG("lvol does not exist\n");
1395 		cb_fn(cb_arg, -EINVAL);
1396 		return;
1397 	}
1398 
1399 	assert(lvol->bdev != NULL);
1400 
1401 	req = calloc(1, sizeof(*req));
1402 	if (req == NULL) {
1403 		cb_fn(cb_arg, -ENOMEM);
1404 		return;
1405 	}
1406 
1407 	req->cb_fn = cb_fn;
1408 	req->cb_arg = cb_arg;
1409 	req->sz = sz;
1410 	req->lvol = lvol;
1411 
1412 	spdk_lvol_resize(req->lvol, req->sz, _vbdev_lvol_resize_cb, req);
1413 }
1414 
1415 static void
1416 _vbdev_lvol_set_read_only_cb(void *cb_arg, int lvolerrno)
1417 {
1418 	struct spdk_lvol_req *req = cb_arg;
1419 	struct spdk_lvol *lvol = req->lvol;
1420 
1421 	if (lvolerrno != 0) {
1422 		SPDK_ERRLOG("Could not set bdev lvol %s as read only due to error: %d.\n", lvol->name, lvolerrno);
1423 	}
1424 
1425 	req->cb_fn(req->cb_arg, lvolerrno);
1426 	free(req);
1427 }
1428 
1429 void
1430 vbdev_lvol_set_read_only(struct spdk_lvol *lvol, spdk_lvol_op_complete cb_fn, void *cb_arg)
1431 {
1432 	struct spdk_lvol_req *req;
1433 
1434 	if (lvol == NULL) {
1435 		SPDK_ERRLOG("lvol does not exist\n");
1436 		cb_fn(cb_arg, -EINVAL);
1437 		return;
1438 	}
1439 
1440 	assert(lvol->bdev != NULL);
1441 
1442 	req = calloc(1, sizeof(*req));
1443 	if (req == NULL) {
1444 		cb_fn(cb_arg, -ENOMEM);
1445 		return;
1446 	}
1447 
1448 	req->cb_fn = cb_fn;
1449 	req->cb_arg = cb_arg;
1450 	req->lvol = lvol;
1451 
1452 	spdk_lvol_set_read_only(lvol, _vbdev_lvol_set_read_only_cb, req);
1453 }
1454 
1455 static int
1456 vbdev_lvs_init(void)
1457 {
1458 	return 0;
1459 }
1460 
1461 static void vbdev_lvs_fini_start_iter(struct lvol_store_bdev *lvs_bdev);
1462 
1463 static void
1464 vbdev_lvs_fini_start_unload_cb(void *cb_arg, int lvserrno)
1465 {
1466 	struct lvol_store_bdev *lvs_bdev = cb_arg;
1467 	struct lvol_store_bdev *next_lvs_bdev = vbdev_lvol_store_next(lvs_bdev);
1468 
1469 	if (lvserrno != 0) {
1470 		SPDK_INFOLOG(vbdev_lvol, "Lvol store removed with error: %d.\n", lvserrno);
1471 	}
1472 
1473 	TAILQ_REMOVE(&g_spdk_lvol_pairs, lvs_bdev, lvol_stores);
1474 	free(lvs_bdev);
1475 
1476 	vbdev_lvs_fini_start_iter(next_lvs_bdev);
1477 }
1478 
1479 static void
1480 vbdev_lvs_fini_start_iter(struct lvol_store_bdev *lvs_bdev)
1481 {
1482 	struct spdk_lvol_store *lvs;
1483 
1484 	while (lvs_bdev != NULL) {
1485 		lvs = lvs_bdev->lvs;
1486 
1487 		if (_vbdev_lvs_are_lvols_closed(lvs)) {
1488 			spdk_lvs_unload(lvs, vbdev_lvs_fini_start_unload_cb, lvs_bdev);
1489 			return;
1490 		}
1491 		lvs_bdev = vbdev_lvol_store_next(lvs_bdev);
1492 	}
1493 
1494 	spdk_bdev_module_fini_start_done();
1495 }
1496 
1497 static void
1498 vbdev_lvs_fini_start(void)
1499 {
1500 	g_shutdown_started = true;
1501 	vbdev_lvs_fini_start_iter(vbdev_lvol_store_first());
1502 }
1503 
1504 static int
1505 vbdev_lvs_get_ctx_size(void)
1506 {
1507 	return sizeof(struct vbdev_lvol_io);
1508 }
1509 
1510 static void
1511 _vbdev_lvs_examine_done(struct spdk_lvs_req *req, int lvserrno)
1512 {
1513 	req->cb_fn(req->cb_arg, lvserrno);
1514 }
1515 
1516 static void
1517 _vbdev_lvs_examine_failed(void *cb_arg, int lvserrno)
1518 {
1519 	struct spdk_lvs_req *req = cb_arg;
1520 
1521 	_vbdev_lvs_examine_done(req, req->lvserrno);
1522 }
1523 
1524 static void
1525 _vbdev_lvs_examine_finish(void *cb_arg, struct spdk_lvol *lvol, int lvolerrno)
1526 {
1527 	struct spdk_lvs_req *req = cb_arg;
1528 	struct spdk_lvol_store *lvs = req->lvol_store;
1529 
1530 	if (lvolerrno != 0) {
1531 		TAILQ_REMOVE(&lvs->lvols, lvol, link);
1532 		if (lvolerrno == -ENOMEM) {
1533 			TAILQ_INSERT_TAIL(&lvs->retry_open_lvols, lvol, link);
1534 			return;
1535 		}
1536 		SPDK_ERRLOG("Error opening lvol %s\n", lvol->unique_id);
1537 		lvs->lvol_count--;
1538 		free(lvol);
1539 		goto end;
1540 	}
1541 
1542 	if (_create_lvol_disk(lvol, false)) {
1543 		SPDK_ERRLOG("Cannot create bdev for lvol %s\n", lvol->unique_id);
1544 		lvs->lvol_count--;
1545 		goto end;
1546 	}
1547 
1548 	lvs->lvols_opened++;
1549 	SPDK_INFOLOG(vbdev_lvol, "Opening lvol %s succeeded\n", lvol->unique_id);
1550 
1551 end:
1552 	if (!TAILQ_EMPTY(&lvs->retry_open_lvols)) {
1553 		lvol = TAILQ_FIRST(&lvs->retry_open_lvols);
1554 		TAILQ_REMOVE(&lvs->retry_open_lvols, lvol, link);
1555 		TAILQ_INSERT_HEAD(&lvs->lvols, lvol, link);
1556 		spdk_lvol_open(lvol, _vbdev_lvs_examine_finish, req);
1557 		return;
1558 	}
1559 	if (lvs->lvols_opened >= lvs->lvol_count) {
1560 		SPDK_INFOLOG(vbdev_lvol, "Opening lvols finished\n");
1561 		_vbdev_lvs_examine_done(req, 0);
1562 	}
1563 }
1564 
1565 /* Walks a tree of clones that are no longer degraded to create bdevs. */
1566 static int
1567 create_esnap_clone_lvol_disks(void *ctx, struct spdk_lvol *lvol)
1568 {
1569 	struct spdk_bdev *bdev = ctx;
1570 	int rc;
1571 
1572 	rc = _create_lvol_disk(lvol, false);
1573 	if (rc != 0) {
1574 		SPDK_ERRLOG("lvol %s: failed to create bdev after esnap hotplug of %s: %d\n",
1575 			    lvol->unique_id, spdk_bdev_get_name(bdev), rc);
1576 		/* Do not prevent creation of other clones in case of one failure. */
1577 		return 0;
1578 	}
1579 
1580 	return spdk_lvol_iter_immediate_clones(lvol, create_esnap_clone_lvol_disks, ctx);
1581 }
1582 
1583 static void
1584 vbdev_lvs_hotplug(void *ctx, struct spdk_lvol *lvol, int lvolerrno)
1585 {
1586 	struct spdk_bdev *esnap_clone_bdev = ctx;
1587 
1588 	if (lvolerrno != 0) {
1589 		SPDK_ERRLOG("lvol %s: during examine of bdev %s: not creating clone bdev due to "
1590 			    "error %d\n", lvol->unique_id, spdk_bdev_get_name(esnap_clone_bdev),
1591 			    lvolerrno);
1592 		return;
1593 	}
1594 	create_esnap_clone_lvol_disks(esnap_clone_bdev, lvol);
1595 }
1596 
1597 static void
1598 vbdev_lvs_examine_config(struct spdk_bdev *bdev)
1599 {
1600 	char uuid_str[SPDK_UUID_STRING_LEN];
1601 
1602 	spdk_uuid_fmt_lower(uuid_str, sizeof(uuid_str), &bdev->uuid);
1603 
1604 	if (spdk_lvs_notify_hotplug(uuid_str, sizeof(uuid_str), vbdev_lvs_hotplug, bdev)) {
1605 		SPDK_INFOLOG(vbdev_lvol, "bdev %s: claimed by one or more esnap clones\n",
1606 			     uuid_str);
1607 	}
1608 	spdk_bdev_module_examine_done(&g_lvol_if);
1609 }
1610 
1611 static void
1612 _vbdev_lvs_examine_cb(void *arg, struct spdk_lvol_store *lvol_store, int lvserrno)
1613 {
1614 	struct lvol_store_bdev *lvs_bdev;
1615 	struct spdk_lvs_with_handle_req *req = (struct spdk_lvs_with_handle_req *)arg;
1616 	struct spdk_lvol *lvol, *tmp;
1617 	struct spdk_lvs_req *ori_req = req->cb_arg;
1618 
1619 	if (lvserrno == -EEXIST) {
1620 		SPDK_INFOLOG(vbdev_lvol,
1621 			     "Name for lvolstore on device %s conflicts with name for already loaded lvs\n",
1622 			     req->base_bdev->name);
1623 		/* On error blobstore destroys bs_dev itself */
1624 		_vbdev_lvs_examine_done(ori_req, lvserrno);
1625 		goto end;
1626 	} else if (lvserrno != 0) {
1627 		SPDK_INFOLOG(vbdev_lvol, "Lvol store not found on %s\n", req->base_bdev->name);
1628 		/* On error blobstore destroys bs_dev itself */
1629 		_vbdev_lvs_examine_done(ori_req, lvserrno);
1630 		goto end;
1631 	}
1632 
1633 	lvserrno = spdk_bs_bdev_claim(lvol_store->bs_dev, &g_lvol_if);
1634 	if (lvserrno != 0) {
1635 		SPDK_INFOLOG(vbdev_lvol, "Lvol store base bdev already claimed by another bdev\n");
1636 		ori_req->lvserrno = lvserrno;
1637 		spdk_lvs_unload(lvol_store, _vbdev_lvs_examine_failed, ori_req);
1638 		goto end;
1639 	}
1640 
1641 	lvs_bdev = calloc(1, sizeof(*lvs_bdev));
1642 	if (!lvs_bdev) {
1643 		SPDK_ERRLOG("Cannot alloc memory for lvs_bdev\n");
1644 		ori_req->lvserrno = lvserrno;
1645 		spdk_lvs_unload(lvol_store, _vbdev_lvs_examine_failed, ori_req);
1646 		goto end;
1647 	}
1648 
1649 	lvs_bdev->lvs = lvol_store;
1650 	lvs_bdev->bdev = req->base_bdev;
1651 
1652 	TAILQ_INSERT_TAIL(&g_spdk_lvol_pairs, lvs_bdev, lvol_stores);
1653 
1654 	SPDK_INFOLOG(vbdev_lvol, "Lvol store found on %s - begin parsing\n",
1655 		     req->base_bdev->name);
1656 
1657 	lvol_store->lvols_opened = 0;
1658 
1659 	ori_req->lvol_store = lvol_store;
1660 
1661 	if (TAILQ_EMPTY(&lvol_store->lvols)) {
1662 		SPDK_INFOLOG(vbdev_lvol, "Lvol store examination done\n");
1663 		_vbdev_lvs_examine_done(ori_req, 0);
1664 	} else {
1665 		/* Open all lvols */
1666 		TAILQ_FOREACH_SAFE(lvol, &lvol_store->lvols, link, tmp) {
1667 			spdk_lvol_open(lvol, _vbdev_lvs_examine_finish, ori_req);
1668 		}
1669 	}
1670 
1671 end:
1672 	free(req);
1673 }
1674 
1675 static void
1676 _vbdev_lvs_examine(struct spdk_bdev *bdev, struct spdk_lvs_req *ori_req,
1677 		   void (*action)(struct spdk_bs_dev *bs_dev, spdk_lvs_op_with_handle_complete cb_fn, void *cb_arg))
1678 {
1679 	struct spdk_bs_dev *bs_dev;
1680 	struct spdk_lvs_with_handle_req *req;
1681 	int rc;
1682 
1683 	req = calloc(1, sizeof(*req));
1684 	if (req == NULL) {
1685 		SPDK_ERRLOG("Cannot alloc memory for vbdev lvol store request pointer\n");
1686 		_vbdev_lvs_examine_done(ori_req, -ENOMEM);
1687 		return;
1688 	}
1689 
1690 	rc = spdk_bdev_create_bs_dev_ext(bdev->name, vbdev_lvs_base_bdev_event_cb,
1691 					 NULL, &bs_dev);
1692 	if (rc < 0) {
1693 		SPDK_INFOLOG(vbdev_lvol, "Cannot create bs dev on %s\n", bdev->name);
1694 		_vbdev_lvs_examine_done(ori_req, rc);
1695 		free(req);
1696 		return;
1697 	}
1698 
1699 	req->base_bdev = bdev;
1700 	req->cb_arg = ori_req;
1701 
1702 	action(bs_dev, _vbdev_lvs_examine_cb, req);
1703 }
1704 
1705 static void
1706 vbdev_lvs_examine_done(void *arg, int lvserrno)
1707 {
1708 	struct spdk_lvs_req *req = arg;
1709 
1710 	spdk_bdev_module_examine_done(&g_lvol_if);
1711 	free(req);
1712 }
1713 
1714 static void
1715 vbdev_lvs_load(struct spdk_bs_dev *bs_dev, spdk_lvs_op_with_handle_complete cb_fn, void *cb_arg)
1716 {
1717 	struct spdk_lvs_opts lvs_opts;
1718 
1719 	spdk_lvs_opts_init(&lvs_opts);
1720 	lvs_opts.esnap_bs_dev_create = vbdev_lvol_esnap_dev_create;
1721 	spdk_lvs_load_ext(bs_dev, &lvs_opts, cb_fn, cb_arg);
1722 }
1723 
1724 static void
1725 vbdev_lvs_examine_disk(struct spdk_bdev *bdev)
1726 {
1727 	struct spdk_lvs_req *req;
1728 
1729 	if (spdk_bdev_get_md_size(bdev) != 0) {
1730 		SPDK_INFOLOG(vbdev_lvol, "Cannot create bs dev on %s\n which is formatted with metadata",
1731 			     bdev->name);
1732 		spdk_bdev_module_examine_done(&g_lvol_if);
1733 		return;
1734 	}
1735 
1736 	req = calloc(1, sizeof(*req));
1737 	if (req == NULL) {
1738 		SPDK_ERRLOG("Cannot alloc memory for vbdev lvol store request pointer\n");
1739 		spdk_bdev_module_examine_done(&g_lvol_if);
1740 		return;
1741 	}
1742 
1743 	req->cb_fn = vbdev_lvs_examine_done;
1744 	req->cb_arg = req;
1745 
1746 	_vbdev_lvs_examine(bdev, req, vbdev_lvs_load);
1747 }
1748 
1749 struct spdk_lvol *
1750 vbdev_lvol_get_from_bdev(struct spdk_bdev *bdev)
1751 {
1752 	if (!bdev || bdev->module != &g_lvol_if) {
1753 		return NULL;
1754 	}
1755 
1756 	if (bdev->ctxt == NULL) {
1757 		SPDK_ERRLOG("No lvol ctx assigned to bdev %s\n", bdev->name);
1758 		return NULL;
1759 	}
1760 
1761 	return (struct spdk_lvol *)bdev->ctxt;
1762 }
1763 
1764 /* Begin degraded blobstore device */
1765 
1766 /*
1767  * When an external snapshot is missing, an instance of bs_dev_degraded is used as the blob's
1768  * back_bs_dev. No bdev is registered, so there should be no IO nor requests for channels. The main
1769  * purposes of this device are to prevent blobstore from hitting fatal runtime errors and to
1770  * indicate that the blob is degraded via the is_degraded() callback.
1771  */
1772 
1773 static void
1774 bs_dev_degraded_read(struct spdk_bs_dev *dev, struct spdk_io_channel *channel, void *payload,
1775 		     uint64_t lba, uint32_t lba_count, struct spdk_bs_dev_cb_args *cb_args)
1776 {
1777 	assert(false);
1778 	cb_args->cb_fn(cb_args->channel, cb_args->cb_arg, -EIO);
1779 }
1780 
1781 static void
1782 bs_dev_degraded_readv(struct spdk_bs_dev *dev, struct spdk_io_channel *channel,
1783 		      struct iovec *iov, int iovcnt, uint64_t lba, uint32_t lba_count,
1784 		      struct spdk_bs_dev_cb_args *cb_args)
1785 {
1786 	assert(false);
1787 	cb_args->cb_fn(cb_args->channel, cb_args->cb_arg, -EIO);
1788 }
1789 
1790 static void
1791 bs_dev_degraded_readv_ext(struct spdk_bs_dev *dev, struct spdk_io_channel *channel,
1792 			  struct iovec *iov, int iovcnt, uint64_t lba, uint32_t lba_count,
1793 			  struct spdk_bs_dev_cb_args *cb_args,
1794 			  struct spdk_blob_ext_io_opts *io_opts)
1795 {
1796 	assert(false);
1797 	cb_args->cb_fn(cb_args->channel, cb_args->cb_arg, -EIO);
1798 }
1799 
1800 static bool
1801 bs_dev_degraded_is_zeroes(struct spdk_bs_dev *dev, uint64_t lba, uint64_t lba_count)
1802 {
1803 	assert(false);
1804 	return false;
1805 }
1806 
1807 static bool
1808 bs_dev_degraded_is_range_valid(struct spdk_bs_dev *dev, uint64_t lba, uint64_t lba_count)
1809 {
1810 	assert(false);
1811 	return false;
1812 }
1813 
1814 static struct spdk_io_channel *
1815 bs_dev_degraded_create_channel(struct spdk_bs_dev *bs_dev)
1816 {
1817 	assert(false);
1818 	return NULL;
1819 }
1820 
1821 static void
1822 bs_dev_degraded_destroy_channel(struct spdk_bs_dev *bs_dev, struct spdk_io_channel *channel)
1823 {
1824 	assert(false);
1825 }
1826 
1827 static void
1828 bs_dev_degraded_destroy(struct spdk_bs_dev *bs_dev)
1829 {
1830 }
1831 
1832 static bool
1833 bs_dev_degraded_is_degraded(struct spdk_bs_dev *bs_dev)
1834 {
1835 	return true;
1836 }
1837 
1838 static struct spdk_bs_dev bs_dev_degraded = {
1839 	.create_channel = bs_dev_degraded_create_channel,
1840 	.destroy_channel = bs_dev_degraded_destroy_channel,
1841 	.destroy = bs_dev_degraded_destroy,
1842 	.read = bs_dev_degraded_read,
1843 	.readv = bs_dev_degraded_readv,
1844 	.readv_ext = bs_dev_degraded_readv_ext,
1845 	.is_zeroes = bs_dev_degraded_is_zeroes,
1846 	.is_range_valid = bs_dev_degraded_is_range_valid,
1847 	.is_degraded = bs_dev_degraded_is_degraded,
1848 	/* Make the device as large as possible without risk of uint64 overflow. */
1849 	.blockcnt = UINT64_MAX / 512,
1850 	/* Prevent divide by zero errors calculating LBAs that will never be read. */
1851 	.blocklen = 512,
1852 };
1853 
1854 /* End degraded blobstore device */
1855 
1856 /* Begin external snapshot support */
1857 
1858 static void
1859 vbdev_lvol_esnap_bdev_event_cb(enum spdk_bdev_event_type type, struct spdk_bdev *bdev,
1860 			       void *event_ctx)
1861 {
1862 	SPDK_NOTICELOG("bdev name (%s) received unsupported event type %d\n",
1863 		       spdk_bdev_get_name(bdev), type);
1864 }
1865 
1866 int
1867 vbdev_lvol_esnap_dev_create(void *bs_ctx, void *blob_ctx, struct spdk_blob *blob,
1868 			    const void *esnap_id, uint32_t id_len,
1869 			    struct spdk_bs_dev **_bs_dev)
1870 {
1871 	struct spdk_lvol_store	*lvs = bs_ctx;
1872 	struct spdk_lvol	*lvol = blob_ctx;
1873 	struct spdk_bs_dev	*bs_dev = NULL;
1874 	struct spdk_uuid	uuid;
1875 	int			rc;
1876 	char			uuid_str[SPDK_UUID_STRING_LEN] = { 0 };
1877 
1878 	if (esnap_id == NULL) {
1879 		SPDK_ERRLOG("lvol %s: NULL esnap ID\n", lvol->unique_id);
1880 		return -EINVAL;
1881 	}
1882 
1883 	/* Guard against arbitrary names and unterminated UUID strings */
1884 	if (id_len != SPDK_UUID_STRING_LEN) {
1885 		SPDK_ERRLOG("lvol %s: Invalid esnap ID length (%u)\n", lvol->unique_id, id_len);
1886 		return -EINVAL;
1887 	}
1888 
1889 	if (spdk_uuid_parse(&uuid, esnap_id)) {
1890 		SPDK_ERRLOG("lvol %s: Invalid esnap ID: not a UUID\n", lvol->unique_id);
1891 		return -EINVAL;
1892 	}
1893 
1894 	/* Format the UUID the same as it is in the bdev names tree. */
1895 	spdk_uuid_fmt_lower(uuid_str, sizeof(uuid_str), &uuid);
1896 	if (strcmp(uuid_str, esnap_id) != 0) {
1897 		SPDK_WARNLOG("lvol %s: esnap_id '%*s' does not match parsed uuid '%s'\n",
1898 			     lvol->unique_id, SPDK_UUID_STRING_LEN, (const char *)esnap_id,
1899 			     uuid_str);
1900 		assert(false);
1901 	}
1902 
1903 	rc = spdk_bdev_create_bs_dev(uuid_str, false, NULL, 0,
1904 				     vbdev_lvol_esnap_bdev_event_cb, NULL, &bs_dev);
1905 	if (rc != 0) {
1906 		goto fail;
1907 	}
1908 
1909 	rc = spdk_bs_bdev_claim(bs_dev, &g_lvol_if);
1910 	if (rc != 0) {
1911 		SPDK_ERRLOG("lvol %s: unable to claim esnap bdev '%s': %d\n", lvol->unique_id,
1912 			    uuid_str, rc);
1913 		bs_dev->destroy(bs_dev);
1914 		goto fail;
1915 	}
1916 
1917 	*_bs_dev = bs_dev;
1918 	return 0;
1919 
1920 fail:
1921 	/* Unable to open or claim the bdev. This lvol is degraded. */
1922 	bs_dev = &bs_dev_degraded;
1923 	SPDK_NOTICELOG("lvol %s: bdev %s not available: lvol is degraded\n", lvol->unique_id,
1924 		       uuid_str);
1925 
1926 	/*
1927 	 * Be sure not to call spdk_lvs_missing_add() on an lvol that is already degraded. This can
1928 	 * lead to a cycle in the degraded_lvols tailq.
1929 	 */
1930 	if (lvol->degraded_set == NULL) {
1931 		rc = spdk_lvs_esnap_missing_add(lvs, lvol, uuid_str, sizeof(uuid_str));
1932 		if (rc != 0) {
1933 			SPDK_NOTICELOG("lvol %s: unable to register missing esnap device %s: "
1934 				       "it will not be hotplugged if added later\n",
1935 				       lvol->unique_id, uuid_str);
1936 		}
1937 	}
1938 
1939 	*_bs_dev = bs_dev;
1940 	return 0;
1941 }
1942 
1943 /* End external snapshot support */
1944 
1945 static void
1946 _vbdev_lvol_shallow_copy_base_bdev_event_cb(enum spdk_bdev_event_type type, struct spdk_bdev *bdev,
1947 		void *event_ctx)
1948 {
1949 }
1950 
1951 static void
1952 _vbdev_lvol_shallow_copy_cb(void *cb_arg, int lvolerrno)
1953 {
1954 	struct spdk_lvol_copy_req *req = cb_arg;
1955 	struct spdk_lvol *lvol = req->lvol;
1956 
1957 	if (lvolerrno != 0) {
1958 		SPDK_ERRLOG("Could not make a shallow copy of lvol %s due to error: %d\n",
1959 			    lvol->name, lvolerrno);
1960 	}
1961 
1962 	req->ext_dev->destroy(req->ext_dev);
1963 	req->cb_fn(req->cb_arg, lvolerrno);
1964 	free(req);
1965 }
1966 
1967 int
1968 vbdev_lvol_shallow_copy(struct spdk_lvol *lvol, const char *bdev_name,
1969 			spdk_blob_shallow_copy_status status_cb_fn, void *status_cb_arg,
1970 			spdk_lvol_op_complete cb_fn, void *cb_arg)
1971 {
1972 	struct spdk_bs_dev *ext_dev;
1973 	struct spdk_lvol_copy_req *req;
1974 	int rc;
1975 
1976 	if (lvol == NULL) {
1977 		SPDK_ERRLOG("lvol must not be NULL\n");
1978 		return -EINVAL;
1979 	}
1980 
1981 	if (bdev_name == NULL) {
1982 		SPDK_ERRLOG("lvol %s, bdev name must not be NULL\n", lvol->name);
1983 		return -EINVAL;
1984 	}
1985 
1986 	assert(lvol->bdev != NULL);
1987 
1988 	req = calloc(1, sizeof(*req));
1989 	if (req == NULL) {
1990 		SPDK_ERRLOG("lvol %s, cannot alloc memory for lvol copy request\n", lvol->name);
1991 		return -ENOMEM;
1992 	}
1993 
1994 	rc = spdk_bdev_create_bs_dev_ext(bdev_name, _vbdev_lvol_shallow_copy_base_bdev_event_cb,
1995 					 NULL, &ext_dev);
1996 	if (rc < 0) {
1997 		SPDK_ERRLOG("lvol %s, cannot create blobstore block device from bdev %s\n", lvol->name, bdev_name);
1998 		free(req);
1999 		return rc;
2000 	}
2001 
2002 	rc = spdk_bs_bdev_claim(ext_dev, &g_lvol_if);
2003 	if (rc != 0) {
2004 		SPDK_ERRLOG("lvol %s, unable to claim bdev %s, error %d\n", lvol->name, bdev_name, rc);
2005 		ext_dev->destroy(ext_dev);
2006 		free(req);
2007 		return rc;
2008 	}
2009 
2010 	req->cb_fn = cb_fn;
2011 	req->cb_arg = cb_arg;
2012 	req->lvol = lvol;
2013 	req->ext_dev = ext_dev;
2014 
2015 	rc = spdk_lvol_shallow_copy(lvol, ext_dev, status_cb_fn, status_cb_arg, _vbdev_lvol_shallow_copy_cb,
2016 				    req);
2017 
2018 	if (rc < 0) {
2019 		ext_dev->destroy(ext_dev);
2020 		free(req);
2021 	}
2022 
2023 	return rc;
2024 }
2025 
2026 void
2027 vbdev_lvol_set_external_parent(struct spdk_lvol *lvol, const char *esnap_name,
2028 			       spdk_lvol_op_complete cb_fn, void *cb_arg)
2029 {
2030 	struct spdk_bdev_desc *desc;
2031 	struct spdk_bdev *bdev;
2032 	char bdev_uuid[SPDK_UUID_STRING_LEN];
2033 	int rc;
2034 
2035 	rc = spdk_bdev_open_ext(esnap_name, false, ignore_bdev_event_cb, NULL, &desc);
2036 	if (rc != 0) {
2037 		SPDK_ERRLOG("bdev '%s' could not be opened: error %d\n", esnap_name, rc);
2038 		cb_fn(cb_arg, -ENODEV);
2039 		return;
2040 	}
2041 	bdev = spdk_bdev_desc_get_bdev(desc);
2042 
2043 	rc = spdk_uuid_fmt_lower(bdev_uuid, sizeof(bdev_uuid), spdk_bdev_get_uuid(bdev));
2044 	if (rc != 0) {
2045 		spdk_bdev_close(desc);
2046 		SPDK_ERRLOG("bdev %s: unable to parse UUID\n", esnap_name);
2047 		assert(false);
2048 		cb_fn(cb_arg, -ENODEV);
2049 		return;
2050 	}
2051 
2052 	/*
2053 	 * If lvol store is not loaded from disk, and so vbdev_lvs_load is not called, these
2054 	 * assignments are necessary to let vbdev_lvol_esnap_dev_create be called.
2055 	 */
2056 	lvol->lvol_store->load_esnaps = true;
2057 	lvol->lvol_store->esnap_bs_dev_create = vbdev_lvol_esnap_dev_create;
2058 
2059 	spdk_lvol_set_external_parent(lvol, bdev_uuid, sizeof(bdev_uuid), cb_fn, cb_arg);
2060 
2061 	spdk_bdev_close(desc);
2062 }
2063 
2064 SPDK_LOG_REGISTER_COMPONENT(vbdev_lvol)
2065