xref: /spdk/lib/ftl/utils/ftl_md.c (revision f8410506e19c71a2a8979946bd5ca0314d2146d4)
1 /*   SPDX-License-Identifier: BSD-3-Clause
2  *   Copyright 2023 Solidigm All Rights Reserved
3  *   Copyright (C) 2022 Intel Corporation.
4  *   All rights reserved.
5  */
6 
7 #include "spdk/env.h"
8 #include "spdk/bdev_module.h"
9 
10 #include "ftl_core.h"
11 #include "ftl_md.h"
12 #include "ftl_nv_cache_io.h"
13 
14 struct ftl_md;
15 static void io_submit(struct ftl_md *md);
16 static void io_done(struct ftl_md *md);
17 
18 static bool
19 has_mirror(struct ftl_md *md)
20 {
21 	if (md->region) {
22 		if (md->region->mirror_type != FTL_LAYOUT_REGION_TYPE_INVALID) {
23 			return md->mirror_enabled;
24 		}
25 	}
26 
27 	return false;
28 }
29 
30 static struct ftl_md *
31 ftl_md_get_mirror(struct ftl_md *md)
32 {
33 	if (has_mirror(md)) {
34 		return md->dev->layout.md[md->region->mirror_type];
35 	}
36 
37 	return NULL;
38 }
39 
40 uint64_t
41 ftl_md_xfer_blocks(struct spdk_ftl_dev *dev)
42 {
43 	return 4ULL * dev->xfer_size;
44 }
45 
46 static uint64_t
47 xfer_size(struct ftl_md *md)
48 {
49 	return ftl_md_xfer_blocks(md->dev) * FTL_BLOCK_SIZE;
50 }
51 
52 static void
53 ftl_md_create_heap(struct ftl_md *md, uint64_t vss_blksz)
54 {
55 	md->shm_fd = -1;
56 	md->vss_data = NULL;
57 	md->data = calloc(md->data_blocks, FTL_BLOCK_SIZE + vss_blksz);
58 
59 	if (md->data && vss_blksz) {
60 		md->vss_data = ((char *)md->data) + md->data_blocks * FTL_BLOCK_SIZE;
61 	}
62 }
63 
64 static void
65 ftl_md_destroy_heap(struct ftl_md *md)
66 {
67 	if (md->data) {
68 		free(md->data);
69 		md->data = NULL;
70 		md->vss_data = NULL;
71 	}
72 }
73 
74 static int
75 ftl_wrapper_open(const char *name, int of, mode_t m)
76 {
77 	return open(name, of, m);
78 }
79 
80 static void
81 ftl_md_setup_obj(struct ftl_md *md, int flags,
82 		 const char *name)
83 {
84 	char uuid_str[SPDK_UUID_STRING_LEN];
85 	const char *fmt;
86 
87 	if (!(flags & FTL_MD_CREATE_SHM)) {
88 		assert(false);
89 		return;
90 	}
91 
92 	/* TODO: temporary, define a proper hugetlbfs mountpoint */
93 	fmt = "/dev/hugepages/ftl_%s_%s";
94 	md->shm_mmap_flags = MAP_SHARED;
95 	md->shm_open = ftl_wrapper_open;
96 	md->shm_unlink = unlink;
97 
98 	if (name == NULL ||
99 	    spdk_uuid_fmt_lower(uuid_str, SPDK_UUID_STRING_LEN, &md->dev->conf.uuid) ||
100 	    snprintf(md->name, sizeof(md->name) / sizeof(md->name[0]),
101 		     fmt, uuid_str, name) <= 0) {
102 		md->name[0] = 0;
103 	}
104 }
105 
106 static void
107 ftl_md_invalidate_shm(struct ftl_md *md)
108 {
109 	if (md->dev->sb_shm && md->dev->sb_shm->shm_ready) {
110 		md->dev->init_retry = true;
111 		md->dev->sb_shm->shm_ready = false;
112 	}
113 }
114 
115 static void
116 ftl_md_create_shm(struct ftl_md *md, uint64_t vss_blksz, int flags)
117 {
118 	struct stat shm_stat;
119 	size_t vss_blk_offs;
120 	void *shm_ptr;
121 	int open_flags = O_RDWR;
122 	mode_t open_mode = S_IRUSR | S_IWUSR;
123 
124 	assert(md->shm_open && md->shm_unlink);
125 	md->data = NULL;
126 	md->vss_data = NULL;
127 	md->shm_sz = 0;
128 
129 	/* Must have an object name */
130 	if (md->name[0] == 0) {
131 		assert(false);
132 		return;
133 	}
134 
135 	/* If specified, unlink before create a new SHM object */
136 	if (flags & FTL_MD_CREATE_SHM_NEW) {
137 		if (md->shm_unlink(md->name) < 0 && errno != ENOENT) {
138 			ftl_md_invalidate_shm(md);
139 			return;
140 		}
141 		open_flags += O_CREAT | O_TRUNC;
142 	}
143 
144 	/* Open existing or create a new SHM object, then query its props */
145 	md->shm_fd = md->shm_open(md->name, open_flags, open_mode);
146 	if (md->shm_fd < 0 || fstat(md->shm_fd, &shm_stat) < 0) {
147 		goto err_shm;
148 	}
149 
150 	/* Verify open mode hasn't changed */
151 	if ((shm_stat.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO)) != open_mode) {
152 		goto err_shm;
153 	}
154 
155 	/* Round up the SHM obj size to the nearest blk size (i.e. page size) */
156 	md->shm_sz = spdk_divide_round_up(md->data_blocks * FTL_BLOCK_SIZE, shm_stat.st_blksize);
157 
158 	/* Add some blks for VSS metadata */
159 	vss_blk_offs = md->shm_sz;
160 
161 	if (vss_blksz) {
162 		md->shm_sz += spdk_divide_round_up(md->data_blocks * vss_blksz,
163 						   shm_stat.st_blksize);
164 	}
165 
166 	/* Total SHM obj size */
167 	md->shm_sz *= shm_stat.st_blksize;
168 
169 	/* Set or check the object size - zero init`d in case of set (FTL_MD_CREATE_SHM_NEW) */
170 	if ((shm_stat.st_size == 0 && (ftruncate(md->shm_fd, md->shm_sz) < 0 ||
171 				       (flags & FTL_MD_CREATE_SHM_NEW) == 0))
172 	    || (shm_stat.st_size > 0 && (size_t)shm_stat.st_size != md->shm_sz)) {
173 		goto err_shm;
174 	}
175 
176 	/* Create a virtual memory mapping for the object */
177 	shm_ptr = mmap(NULL, md->shm_sz, PROT_READ | PROT_WRITE, md->shm_mmap_flags,
178 		       md->shm_fd, 0);
179 	if (shm_ptr == MAP_FAILED) {
180 		goto err_shm;
181 	}
182 
183 	md->data = shm_ptr;
184 	if (vss_blksz) {
185 		md->vss_data = ((char *)shm_ptr) + vss_blk_offs * shm_stat.st_blksize;
186 	}
187 
188 	/* Lock the pages in memory (i.e. prevent the pages to be paged out) */
189 	if (mlock(md->data, md->shm_sz) < 0) {
190 		goto err_map;
191 	}
192 
193 	if (spdk_mem_register(md->data, md->shm_sz)) {
194 		goto err_mlock;
195 	}
196 	md->mem_reg = true;
197 
198 	return;
199 
200 	/* Cleanup upon fault */
201 err_mlock:
202 	munlock(md->data, md->shm_sz);
203 
204 err_map:
205 	munmap(md->data, md->shm_sz);
206 	md->data = NULL;
207 	md->vss_data = NULL;
208 	md->shm_sz = 0;
209 
210 err_shm:
211 	if (md->shm_fd >= 0) {
212 		close(md->shm_fd);
213 		md->shm_unlink(md->name);
214 		md->shm_fd = -1;
215 	}
216 	ftl_md_invalidate_shm(md);
217 }
218 
219 static void
220 ftl_md_destroy_shm(struct ftl_md *md, int flags)
221 {
222 	if (!md->data) {
223 		return;
224 	}
225 
226 	assert(md->shm_sz > 0);
227 	if (md->mem_reg) {
228 		spdk_mem_unregister(md->data, md->shm_sz);
229 		md->mem_reg = false;
230 	}
231 
232 	/* Unlock the pages in memory */
233 	munlock(md->data, md->shm_sz);
234 
235 	/* Remove the virtual memory mapping for the object */
236 	munmap(md->data, md->shm_sz);
237 
238 	/* Close SHM object fd */
239 	close(md->shm_fd);
240 
241 	md->data = NULL;
242 	md->vss_data = NULL;
243 
244 	/* If specified, keep the object in SHM */
245 	if (flags & FTL_MD_DESTROY_SHM_KEEP) {
246 		return;
247 	}
248 
249 	/* Otherwise destroy/unlink the object */
250 	assert(md->name[0] != 0 && md->shm_unlink != NULL);
251 	md->shm_unlink(md->name);
252 }
253 
254 struct ftl_md *ftl_md_create(struct spdk_ftl_dev *dev, uint64_t blocks,
255 			     uint64_t vss_blksz, const char *name, int flags,
256 			     const struct ftl_layout_region *region)
257 {
258 	struct ftl_md *md;
259 
260 	md = calloc(1, sizeof(*md));
261 	if (!md) {
262 		return NULL;
263 	}
264 	md->dev = dev;
265 	md->data_blocks = blocks;
266 	md->mirror_enabled = true;
267 
268 	if (flags != FTL_MD_CREATE_NO_MEM) {
269 		if (flags & FTL_MD_CREATE_SHM) {
270 			ftl_md_setup_obj(md, flags, name);
271 			ftl_md_create_shm(md, vss_blksz, flags);
272 		} else {
273 			assert((flags & FTL_MD_CREATE_HEAP) == FTL_MD_CREATE_HEAP);
274 			ftl_md_create_heap(md, vss_blksz);
275 		}
276 
277 		if (!md->data) {
278 			free(md);
279 			return NULL;
280 		}
281 	}
282 
283 	if (region) {
284 		size_t entry_vss_buf_size = vss_blksz * region->entry_size;
285 
286 		if (entry_vss_buf_size) {
287 			md->entry_vss_dma_buf = spdk_malloc(entry_vss_buf_size, FTL_BLOCK_SIZE,
288 							    NULL, SPDK_ENV_LCORE_ID_ANY,
289 							    SPDK_MALLOC_DMA);
290 			if (!md->entry_vss_dma_buf) {
291 				goto err;
292 			}
293 		}
294 
295 		ftl_md_set_region(md, region);
296 	}
297 
298 	return md;
299 err:
300 	ftl_md_destroy(md, ftl_md_destroy_region_flags(dev, region->type));
301 	return NULL;
302 }
303 
304 int
305 ftl_md_unlink(struct spdk_ftl_dev *dev, const char *name, int flags)
306 {
307 	struct ftl_md md = { 0 };
308 
309 	if (0 == (flags & FTL_MD_CREATE_SHM)) {
310 		/* Unlink can be called for shared memory only */
311 		return -EINVAL;
312 	}
313 
314 	md.dev = dev;
315 	ftl_md_setup_obj(&md, flags, name);
316 
317 	return md.shm_unlink(md.name);
318 }
319 
320 void
321 ftl_md_destroy(struct ftl_md *md, int flags)
322 {
323 	if (!md) {
324 		return;
325 	}
326 
327 	if (!md->is_mirror) {
328 		ftl_md_free_buf(md, flags);
329 		spdk_free(md->entry_vss_dma_buf);
330 	}
331 	free(md);
332 }
333 
334 void
335 ftl_md_free_buf(struct ftl_md *md, int flags)
336 {
337 	if (!md) {
338 		return;
339 	}
340 
341 	if (md->shm_fd < 0) {
342 		assert(flags == 0);
343 		ftl_md_destroy_heap(md);
344 	} else {
345 		ftl_md_destroy_shm(md, flags);
346 	}
347 }
348 
349 void *
350 ftl_md_get_buffer(struct ftl_md *md)
351 {
352 	return md->data;
353 }
354 
355 uint64_t
356 ftl_md_get_buffer_size(struct ftl_md *md)
357 {
358 	return md->data_blocks * FTL_BLOCK_SIZE;
359 }
360 
361 static void
362 ftl_md_vss_buf_init(union ftl_md_vss *buf, uint32_t count,
363 		    const union ftl_md_vss *vss_pattern)
364 {
365 	while (count) {
366 		count--;
367 		buf[count] = *vss_pattern;
368 	}
369 }
370 
371 union ftl_md_vss *ftl_md_vss_buf_alloc(struct ftl_layout_region *region, uint32_t count)
372 {
373 	union ftl_md_vss *buf = spdk_zmalloc(count * FTL_MD_VSS_SZ, FTL_BLOCK_SIZE, NULL,
374 						     SPDK_ENV_LCORE_ID_ANY,
375 						     SPDK_MALLOC_DMA);
376 
377 	if (!buf) {
378 		return NULL;
379 	}
380 
381 	union ftl_md_vss vss_buf = {0};
382 	vss_buf.version.md_version = region->current.version;
383 	ftl_md_vss_buf_init(buf, count, &vss_buf);
384 	return buf;
385 }
386 
387 union ftl_md_vss *ftl_md_get_vss_buffer(struct ftl_md *md)
388 {
389 	return md->vss_data;
390 }
391 
392 static void
393 io_cleanup(struct ftl_md *md)
394 {
395 	spdk_dma_free(md->io.data);
396 	md->io.data = NULL;
397 
398 	spdk_dma_free(md->io.md);
399 	md->io.md = NULL;
400 }
401 
402 static void
403 exception(void *arg)
404 {
405 	struct ftl_md *md = arg;
406 
407 	md->cb(md->dev, md, -EINVAL);
408 	io_cleanup(md);
409 }
410 
411 static inline enum ftl_stats_type
412 get_bdev_io_ftl_stats_type(struct spdk_ftl_dev *dev, struct spdk_bdev_io *bdev_io) {
413 	struct spdk_bdev *nvc = spdk_bdev_desc_get_bdev(dev->nv_cache.bdev_desc);
414 
415 	if (bdev_io->bdev == nvc)
416 	{
417 		return FTL_STATS_TYPE_MD_NV_CACHE;
418 	} else
419 	{
420 		return FTL_STATS_TYPE_MD_BASE;
421 	}
422 }
423 
424 static void
425 audit_md_vss_version(struct ftl_md *md, uint64_t blocks)
426 {
427 #if defined(DEBUG)
428 	union ftl_md_vss *vss = md->io.md;
429 	while (blocks) {
430 		blocks--;
431 		assert(vss[blocks].version.md_version == md->region->current.version);
432 	}
433 #endif
434 }
435 
436 static void
437 read_write_blocks_cb(struct spdk_bdev_io *bdev_io, bool success, void *arg)
438 {
439 	struct ftl_md *md = arg;
440 
441 	ftl_stats_bdev_io_completed(md->dev, get_bdev_io_ftl_stats_type(md->dev, bdev_io), bdev_io);
442 
443 	if (spdk_unlikely(!success)) {
444 		if (md->io.op == FTL_MD_OP_RESTORE && has_mirror(md)) {
445 			md->io.status = -EAGAIN;
446 		} else {
447 			md->io.status = -EIO;
448 		}
449 	} else {
450 		uint64_t blocks = bdev_io->u.bdev.num_blocks;
451 		uint64_t size = blocks * FTL_BLOCK_SIZE;
452 
453 		if (md->io.op == FTL_MD_OP_RESTORE) {
454 			memcpy(md->data + md->io.data_offset, md->io.data, size);
455 
456 			if (md->vss_data) {
457 				uint64_t vss_offset = md->io.data_offset / FTL_BLOCK_SIZE;
458 				vss_offset *= FTL_MD_VSS_SZ;
459 				audit_md_vss_version(md, blocks);
460 				memcpy(md->vss_data + vss_offset, md->io.md, blocks * FTL_MD_VSS_SZ);
461 			}
462 		}
463 
464 		md->io.address += blocks;
465 		md->io.remaining -= blocks;
466 		md->io.data_offset += size;
467 	}
468 
469 	spdk_bdev_free_io(bdev_io);
470 
471 	io_submit(md);
472 }
473 
474 static inline int
475 read_blocks(struct spdk_ftl_dev *dev, struct spdk_bdev_desc *desc,
476 	    struct spdk_io_channel *ch,
477 	    void *buf, void *md_buf,
478 	    uint64_t offset_blocks, uint64_t num_blocks,
479 	    spdk_bdev_io_completion_cb cb, void *cb_arg)
480 {
481 	if (desc == dev->nv_cache.bdev_desc) {
482 		return ftl_nv_cache_bdev_read_blocks_with_md(dev, desc, ch, buf, md_buf,
483 				offset_blocks, num_blocks,
484 				cb, cb_arg);
485 	} else if (md_buf) {
486 		return spdk_bdev_read_blocks_with_md(desc, ch, buf, md_buf,
487 						     offset_blocks, num_blocks,
488 						     cb, cb_arg);
489 	} else {
490 		return spdk_bdev_read_blocks(desc, ch, buf,
491 					     offset_blocks, num_blocks,
492 					     cb, cb_arg);
493 	}
494 }
495 
496 static inline int
497 write_blocks(struct spdk_ftl_dev *dev, struct spdk_bdev_desc *desc,
498 	     struct spdk_io_channel *ch,
499 	     void *buf, void *md_buf,
500 	     uint64_t offset_blocks, uint64_t num_blocks,
501 	     spdk_bdev_io_completion_cb cb, void *cb_arg)
502 {
503 	if (desc == dev->nv_cache.bdev_desc) {
504 		return ftl_nv_cache_bdev_write_blocks_with_md(dev, desc, ch, buf, md_buf,
505 				offset_blocks, num_blocks,
506 				cb, cb_arg);
507 	} else if (md_buf) {
508 		return spdk_bdev_write_blocks_with_md(desc, ch, buf, md_buf, offset_blocks,
509 						      num_blocks, cb, cb_arg);
510 	} else {
511 		return spdk_bdev_write_blocks(desc, ch, buf, offset_blocks, num_blocks, cb, cb_arg);
512 	}
513 }
514 
515 static void
516 read_write_blocks(void *_md)
517 {
518 	struct ftl_md *md = _md;
519 	const struct ftl_layout_region *region = md->region;
520 	uint64_t blocks;
521 	int rc = 0;
522 
523 	blocks = spdk_min(md->io.remaining, ftl_md_xfer_blocks(md->dev));
524 
525 	switch (md->io.op) {
526 	case FTL_MD_OP_RESTORE:
527 		rc = read_blocks(md->dev, region->bdev_desc, region->ioch,
528 				 md->io.data, md->io.md,
529 				 md->io.address, blocks,
530 				 read_write_blocks_cb, md);
531 		break;
532 	case FTL_MD_OP_PERSIST:
533 	case FTL_MD_OP_CLEAR:
534 		rc = write_blocks(md->dev, region->bdev_desc, region->ioch,
535 				  md->io.data, md->io.md,
536 				  md->io.address, blocks,
537 				  read_write_blocks_cb, md);
538 		break;
539 	default:
540 		ftl_abort();
541 	}
542 
543 	if (spdk_unlikely(rc)) {
544 		if (rc == -ENOMEM) {
545 			struct spdk_bdev *bdev = spdk_bdev_desc_get_bdev(region->bdev_desc);
546 			md->io.bdev_io_wait.bdev = bdev;
547 			md->io.bdev_io_wait.cb_fn = read_write_blocks;
548 			md->io.bdev_io_wait.cb_arg = md;
549 			spdk_bdev_queue_io_wait(bdev, region->ioch, &md->io.bdev_io_wait);
550 		} else {
551 			ftl_abort();
552 		}
553 	}
554 }
555 
556 static void
557 io_submit(struct ftl_md *md)
558 {
559 	if (!md->io.remaining || md->io.status) {
560 		io_done(md);
561 		return;
562 	}
563 
564 	if (md->io.op == FTL_MD_OP_PERSIST) {
565 		uint64_t blocks = spdk_min(md->io.remaining, ftl_md_xfer_blocks(md->dev));
566 
567 		memcpy(md->io.data, md->data + md->io.data_offset, FTL_BLOCK_SIZE * blocks);
568 
569 		if (md->vss_data) {
570 			uint64_t vss_offset = md->io.data_offset / FTL_BLOCK_SIZE;
571 			vss_offset *= FTL_MD_VSS_SZ;
572 			assert(md->io.md);
573 			memcpy(md->io.md, md->vss_data + vss_offset, FTL_MD_VSS_SZ * blocks);
574 			audit_md_vss_version(md, blocks);
575 		}
576 	}
577 #if defined(DEBUG)
578 	if (md->io.md && md->io.op == FTL_MD_OP_CLEAR) {
579 		uint64_t blocks = spdk_min(md->io.remaining, ftl_md_xfer_blocks(md->dev));
580 		audit_md_vss_version(md, blocks);
581 	}
582 #endif
583 
584 	read_write_blocks(md);
585 }
586 
587 static int
588 io_can_start(struct ftl_md *md)
589 {
590 	assert(NULL == md->io.data);
591 	if (NULL != md->io.data) {
592 		/* Outgoing IO on metadata */
593 		return -EINVAL;
594 	}
595 
596 	if (!md->region) {
597 		/* No device region to process data */
598 		return -EINVAL;
599 	}
600 
601 	if (md->region->current.blocks > md->data_blocks) {
602 		/* No device region to process data */
603 		FTL_ERRLOG(md->dev, "Blocks number mismatch between metadata object and"
604 			   "device region\n");
605 		return -EINVAL;
606 	}
607 
608 	return 0;
609 }
610 
611 static int
612 io_prepare(struct ftl_md *md, enum ftl_md_ops op)
613 {
614 	const struct ftl_layout_region *region = md->region;
615 	uint64_t data_size, meta_size = 0;
616 
617 	/* Allocates buffer for IO */
618 	data_size = xfer_size(md);
619 	md->io.data = spdk_zmalloc(data_size, FTL_BLOCK_SIZE, NULL,
620 				   SPDK_ENV_LCORE_ID_ANY, SPDK_MALLOC_DMA);
621 	if (!md->io.data) {
622 		return -ENOMEM;
623 	}
624 
625 	if (md->vss_data || md->region->vss_blksz) {
626 		meta_size = ftl_md_xfer_blocks(md->dev) * FTL_MD_VSS_SZ;
627 		md->io.md = spdk_zmalloc(meta_size, FTL_BLOCK_SIZE, NULL,
628 					 SPDK_ENV_LCORE_ID_ANY, SPDK_MALLOC_DMA);
629 		if (!md->io.md) {
630 			spdk_dma_free(md->io.data);
631 			md->io.data = NULL;
632 			return -ENOMEM;
633 		}
634 	}
635 
636 	md->io.address = region->current.offset;
637 	md->io.remaining = region->current.blocks;
638 	md->io.data_offset = 0;
639 	md->io.status = 0;
640 	md->io.op = op;
641 
642 	return 0;
643 }
644 
645 static int
646 io_init(struct ftl_md *md, enum ftl_md_ops op)
647 {
648 	if (io_can_start(md)) {
649 		return -EINVAL;
650 	}
651 
652 	if (io_prepare(md, op)) {
653 		return -ENOMEM;
654 	}
655 
656 	return 0;
657 }
658 
659 static uint64_t
660 persist_entry_lba(struct ftl_md *md, uint64_t start_entry)
661 {
662 	return md->region->current.offset + start_entry * md->region->entry_size;
663 }
664 
665 static void
666 persist_entry_cb(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)
667 {
668 	struct ftl_md_io_entry_ctx *ctx = cb_arg;
669 	struct ftl_md *md = ctx->md;
670 
671 	ftl_stats_bdev_io_completed(md->dev, get_bdev_io_ftl_stats_type(md->dev, bdev_io), bdev_io);
672 
673 	spdk_bdev_free_io(bdev_io);
674 
675 	assert(ctx->remaining > 0);
676 	ctx->remaining--;
677 
678 	if (!success) {
679 		ctx->status = -EIO;
680 	}
681 
682 	if (!ctx->remaining) {
683 		ctx->cb(ctx->status, ctx->cb_arg);
684 	}
685 }
686 
687 static int
688 ftl_md_persist_entry_write_blocks(struct ftl_md_io_entry_ctx *ctx, struct ftl_md *md,
689 				  spdk_bdev_io_wait_cb retry_fn)
690 {
691 	int rc;
692 
693 	rc = write_blocks(md->dev, md->region->bdev_desc, md->region->ioch,
694 			  ctx->buffer, ctx->vss_buffer,
695 			  persist_entry_lba(md, ctx->start_entry), md->region->entry_size,
696 			  persist_entry_cb, ctx);
697 	if (spdk_unlikely(rc)) {
698 		if (rc == -ENOMEM) {
699 			struct spdk_bdev *bdev = spdk_bdev_desc_get_bdev(md->region->bdev_desc);
700 			ctx->bdev_io_wait.bdev = bdev;
701 			ctx->bdev_io_wait.cb_fn = retry_fn;
702 			ctx->bdev_io_wait.cb_arg = ctx;
703 			spdk_bdev_queue_io_wait(bdev, md->region->ioch, &ctx->bdev_io_wait);
704 		} else {
705 			ftl_abort();
706 		}
707 	}
708 
709 	return rc;
710 }
711 
712 static void
713 ftl_md_persist_entry_mirror(void *_ctx)
714 {
715 	struct ftl_md_io_entry_ctx *ctx = _ctx;
716 	struct ftl_md *md_mirror = ftl_md_get_mirror(ctx->md);
717 
718 	ftl_md_persist_entry_write_blocks(ctx, md_mirror, ftl_md_persist_entry_mirror);
719 }
720 
721 static void
722 ftl_md_persist_entry_primary(void *_ctx)
723 {
724 	struct ftl_md_io_entry_ctx *ctx = _ctx;
725 	struct ftl_md *md = ctx->md;
726 	int rc;
727 
728 	rc = ftl_md_persist_entry_write_blocks(ctx, md, ftl_md_persist_entry_primary);
729 
730 	if (!rc && has_mirror(md)) {
731 		assert(md->region->entry_size == (ftl_md_get_mirror(md))->region->entry_size);
732 
733 		/* The MD object has mirror so execute persist on it too */
734 		ftl_md_persist_entry_mirror(ctx);
735 		ctx->remaining++;
736 	}
737 }
738 
739 static void
740 _ftl_md_persist_entry(struct ftl_md_io_entry_ctx *ctx)
741 {
742 	ctx->status = 0;
743 	ctx->remaining = 1;
744 
745 	/* First execute an IO to the primary region */
746 	ftl_md_persist_entry_primary(ctx);
747 }
748 
749 void
750 ftl_md_persist_entry(struct ftl_md *md, uint64_t start_entry, void *buffer, void *vss_buffer,
751 		     ftl_md_io_entry_cb cb, void *cb_arg,
752 		     struct ftl_md_io_entry_ctx *ctx)
753 {
754 	if (spdk_unlikely(0 == md->region->entry_size)) {
755 		/* This MD has not been configured to support persist entry call */
756 		ftl_abort();
757 	}
758 
759 	/* Initialize persist entry context */
760 	ctx->cb = cb;
761 	ctx->cb_arg = cb_arg;
762 	ctx->md = md;
763 	ctx->start_entry = start_entry;
764 	ctx->buffer = buffer;
765 	ctx->vss_buffer = vss_buffer ? : md->entry_vss_dma_buf;
766 
767 	_ftl_md_persist_entry(ctx);
768 }
769 
770 static void
771 read_entry_cb(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)
772 {
773 	struct ftl_md_io_entry_ctx *ctx = cb_arg;
774 	struct ftl_md *md = ctx->md;
775 
776 	ftl_stats_bdev_io_completed(md->dev, get_bdev_io_ftl_stats_type(md->dev, bdev_io), bdev_io);
777 
778 	spdk_bdev_free_io(bdev_io);
779 
780 	if (!success) {
781 		if (has_mirror(md)) {
782 			md->mirror_enabled = true;
783 
784 			/* First read from the mirror */
785 			ftl_md_read_entry(ftl_md_get_mirror(md), ctx->start_entry, ctx->buffer,
786 					  ctx->vss_buffer,
787 					  ctx->cb, ctx->cb_arg,
788 					  ctx);
789 			return;
790 		} else {
791 			ctx->status = -EIO;
792 			goto finish_io;
793 		}
794 	}
795 
796 finish_io:
797 	ctx->cb(ctx->status, ctx->cb_arg);
798 }
799 
800 static void
801 ftl_md_read_entry_read_blocks(struct ftl_md_io_entry_ctx *ctx, struct ftl_md *md,
802 			      spdk_bdev_io_wait_cb retry_fn)
803 {
804 	int rc;
805 
806 	rc = read_blocks(md->dev, md->region->bdev_desc, md->region->ioch,
807 			 ctx->buffer, ctx->vss_buffer,
808 			 persist_entry_lba(md, ctx->start_entry), md->region->entry_size,
809 			 read_entry_cb, ctx);
810 
811 	if (spdk_unlikely(rc)) {
812 		if (rc == -ENOMEM) {
813 			struct spdk_bdev *bdev = spdk_bdev_desc_get_bdev(md->region->bdev_desc);
814 			ctx->bdev_io_wait.bdev = bdev;
815 			ctx->bdev_io_wait.cb_fn = retry_fn;
816 			ctx->bdev_io_wait.cb_arg = ctx;
817 			spdk_bdev_queue_io_wait(bdev, md->region->ioch, &ctx->bdev_io_wait);
818 		} else {
819 			ftl_abort();
820 		}
821 	}
822 }
823 
824 static void
825 _ftl_md_read_entry(void *_ctx)
826 {
827 	struct ftl_md_io_entry_ctx *ctx = _ctx;
828 
829 	ftl_md_read_entry_read_blocks(ctx, ctx->md, _ftl_md_read_entry);
830 }
831 
832 void
833 ftl_md_read_entry(struct ftl_md *md, uint64_t start_entry, void *buffer, void *vss_buffer,
834 		  ftl_md_io_entry_cb cb, void *cb_arg,
835 		  struct ftl_md_io_entry_ctx *ctx)
836 {
837 	if (spdk_unlikely(0 == md->region->entry_size)) {
838 		/* This MD has not been configured to support read entry call */
839 		ftl_abort();
840 	}
841 
842 	ctx->cb = cb;
843 	ctx->cb_arg = cb_arg;
844 	ctx->md = md;
845 	ctx->start_entry = start_entry;
846 	ctx->buffer = buffer;
847 	ctx->vss_buffer = vss_buffer;
848 
849 	_ftl_md_read_entry(ctx);
850 }
851 
852 void
853 ftl_md_persist_entry_retry(struct ftl_md_io_entry_ctx *ctx)
854 {
855 	_ftl_md_persist_entry(ctx);
856 }
857 
858 static void
859 persist_mirror_cb(struct spdk_ftl_dev *dev, struct ftl_md *md, int status)
860 {
861 	struct ftl_md *primary = md->owner.private;
862 
863 	if (status) {
864 		/* We got an error, stop persist procedure immediately */
865 		primary->io.status = status;
866 		io_done(primary);
867 	} else {
868 		/* Now continue the persist procedure on the primary MD object */
869 		if (0 == io_init(primary, FTL_MD_OP_PERSIST)) {
870 			io_submit(primary);
871 		} else {
872 			spdk_thread_send_msg(spdk_get_thread(), exception, primary);
873 		}
874 	}
875 }
876 
877 void
878 ftl_md_persist(struct ftl_md *md)
879 {
880 	if (has_mirror(md)) {
881 		struct ftl_md *md_mirror = ftl_md_get_mirror(md);
882 
883 		md->mirror_enabled = true;
884 
885 		/* Set callback and context in mirror */
886 		md_mirror->cb = persist_mirror_cb;
887 		md_mirror->owner.private = md;
888 
889 		/* First persist the mirror */
890 		ftl_md_persist(md_mirror);
891 		return;
892 	}
893 
894 	if (0 == io_init(md, FTL_MD_OP_PERSIST)) {
895 		io_submit(md);
896 	} else {
897 		spdk_thread_send_msg(spdk_get_thread(), exception, md);
898 	}
899 }
900 
901 static void
902 restore_mirror_cb(struct spdk_ftl_dev *dev, struct ftl_md *md, int status)
903 {
904 	struct ftl_md *primary = md->owner.private;
905 
906 	if (status) {
907 		/* Cannot restore the object from the mirror too, mark error and fail */
908 		primary->io.status = -EIO;
909 		io_done(primary);
910 	} else {
911 		/*
912 		 * Restoring from the mirror successful. Synchronize mirror to the primary.
913 		 * Because we read MD content from the mirror, we can disable it, only the primary
914 		 * requires persisting.
915 		 */
916 		primary->io.status = 0;
917 		primary->mirror_enabled = false;
918 		io_cleanup(primary);
919 		ftl_md_persist(primary);
920 		primary->mirror_enabled = true;
921 	}
922 }
923 
924 static void
925 restore_sync_cb(struct spdk_ftl_dev *dev, struct ftl_md *md, int status)
926 {
927 	struct ftl_md *primary = md->owner.private;
928 
929 	if (status) {
930 		/* Cannot sync the object from the primary to the mirror, mark error and fail */
931 		primary->io.status = -EIO;
932 		io_done(primary);
933 	} else {
934 		primary->cb(dev, primary, primary->io.status);
935 		io_cleanup(primary);
936 	}
937 }
938 
939 static int
940 restore_done(struct ftl_md *md)
941 {
942 	if (-EAGAIN == md->io.status) {
943 		/* Failed to read MD from primary region, try it from mirror.
944 		 * At the moment read the mirror entirely, (TODO) in the
945 		 * feature we can restore from primary and mirror region
946 		 * with finer granularity.
947 		 */
948 
949 		if (has_mirror(md)) {
950 			struct ftl_md *md_mirror = ftl_md_get_mirror(md);
951 
952 			md->mirror_enabled = true;
953 
954 			/* Set callback and context in mirror */
955 			md_mirror->cb = restore_mirror_cb;
956 			md_mirror->owner.private = md;
957 
958 			/* First persist the mirror */
959 			ftl_md_restore(md_mirror);
960 			return -EAGAIN;
961 		} else {
962 			return -EIO;
963 		}
964 	} else if (0 == md->io.status && false == md->dev->sb->clean) {
965 		if (has_mirror(md)) {
966 			struct ftl_md *md_mirror = ftl_md_get_mirror(md);
967 			/* There was a dirty shutdown, synchronize primary to mirror */
968 
969 			/* Set callback and context in the mirror */
970 			md_mirror->cb = restore_sync_cb;
971 			md_mirror->owner.private = md;
972 
973 			/* First persist the mirror */
974 			ftl_md_persist(md_mirror);
975 			return -EAGAIN;
976 		}
977 	}
978 
979 	return md->io.status;
980 }
981 
982 static void
983 io_done(struct ftl_md *md)
984 {
985 	int status;
986 
987 	if (md->io.op == FTL_MD_OP_RESTORE) {
988 		status = restore_done(md);
989 	} else {
990 		status = md->io.status;
991 	}
992 
993 	if (status != -EAGAIN) {
994 		md->cb(md->dev, md, status);
995 		io_cleanup(md);
996 	}
997 }
998 
999 void
1000 ftl_md_restore(struct ftl_md *md)
1001 {
1002 	if (0 == io_init(md, FTL_MD_OP_RESTORE)) {
1003 		io_submit(md);
1004 	} else {
1005 		spdk_thread_send_msg(spdk_get_thread(), exception, md);
1006 	}
1007 }
1008 
1009 static int
1010 pattern_prepare(struct ftl_md *md,
1011 		int data_pattern, union ftl_md_vss *vss_pattern)
1012 {
1013 	void *data = md->io.data;
1014 	uint64_t data_size = xfer_size(md);
1015 
1016 	memset(data, data_pattern, data_size);
1017 
1018 	if (md->io.md) {
1019 		if (vss_pattern) {
1020 			/* store the VSS pattern... */
1021 			ftl_md_vss_buf_init(md->io.md, ftl_md_xfer_blocks(md->dev), vss_pattern);
1022 		} else {
1023 			/* ...or default init VSS to 0 */
1024 			union ftl_md_vss vss = {0};
1025 
1026 			vss.version.md_version = md->region->current.version;
1027 			ftl_md_vss_buf_init(md->io.md, ftl_md_xfer_blocks(md->dev), &vss);
1028 		}
1029 	}
1030 
1031 	return 0;
1032 }
1033 
1034 static void
1035 clear_mirror_cb(struct spdk_ftl_dev *dev, struct ftl_md *secondary, int status)
1036 {
1037 	struct ftl_md *primary = secondary->owner.private;
1038 
1039 	if (status) {
1040 		/* We got an error, stop persist procedure immediately */
1041 		primary->io.status = status;
1042 		io_done(primary);
1043 	} else {
1044 		/* Now continue the persist procedure on the primary MD object */
1045 		if (0 == io_init(primary, FTL_MD_OP_CLEAR) &&
1046 		    0 == pattern_prepare(primary, *(int *)secondary->io.data,
1047 					 secondary->io.md)) {
1048 			io_submit(primary);
1049 		} else {
1050 			spdk_thread_send_msg(spdk_get_thread(), exception, primary);
1051 		}
1052 	}
1053 }
1054 
1055 void
1056 ftl_md_clear(struct ftl_md *md, int data_pattern, union ftl_md_vss *vss_pattern)
1057 {
1058 	if (has_mirror(md)) {
1059 		struct ftl_md *md_mirror = ftl_md_get_mirror(md);
1060 
1061 		md->mirror_enabled = true;
1062 
1063 		/* Set callback and context in mirror */
1064 		md_mirror->cb = clear_mirror_cb;
1065 		md_mirror->owner.private = md;
1066 
1067 		/* First persist the mirror */
1068 		ftl_md_clear(md_mirror, data_pattern, vss_pattern);
1069 		return;
1070 	}
1071 
1072 	if (0 == io_init(md, FTL_MD_OP_CLEAR) && 0 == pattern_prepare(md, data_pattern, vss_pattern)) {
1073 		io_submit(md);
1074 	} else {
1075 		spdk_thread_send_msg(spdk_get_thread(), exception, md);
1076 	}
1077 }
1078 
1079 const struct ftl_layout_region *
1080 ftl_md_get_region(struct ftl_md *md)
1081 {
1082 	return md->region;
1083 }
1084 
1085 void
1086 ftl_md_set_region(struct ftl_md *md,
1087 		  const struct ftl_layout_region *region)
1088 {
1089 	assert(region->current.blocks <= md->data_blocks);
1090 	md->region = region;
1091 
1092 	if (md->vss_data) {
1093 		union ftl_md_vss vss = {0};
1094 		vss.version.md_version = region->current.version;
1095 		ftl_md_vss_buf_init(md->vss_data, md->data_blocks, &vss);
1096 		if (region->entry_size) {
1097 			assert(md->entry_vss_dma_buf);
1098 			ftl_md_vss_buf_init(md->entry_vss_dma_buf, region->entry_size, &vss);
1099 		}
1100 	}
1101 
1102 	if (has_mirror(md)) {
1103 		md->mirror_enabled = true;
1104 	}
1105 }
1106 
1107 int
1108 ftl_md_create_region_flags(struct spdk_ftl_dev *dev, int region_type)
1109 {
1110 	int flags = FTL_MD_CREATE_SHM;
1111 
1112 	switch (region_type) {
1113 	case FTL_LAYOUT_REGION_TYPE_SB:
1114 		if (dev->conf.mode & SPDK_FTL_MODE_CREATE) {
1115 			flags |= FTL_MD_CREATE_SHM_NEW;
1116 		}
1117 		break;
1118 
1119 	case FTL_LAYOUT_REGION_TYPE_BAND_MD:
1120 	case FTL_LAYOUT_REGION_TYPE_NVC_MD:
1121 		if (!ftl_fast_startup(dev)) {
1122 			flags |= FTL_MD_CREATE_SHM_NEW;
1123 		}
1124 		break;
1125 	case FTL_LAYOUT_REGION_TYPE_VALID_MAP:
1126 	case FTL_LAYOUT_REGION_TYPE_TRIM_MD:
1127 		if (!ftl_fast_startup(dev) && !ftl_fast_recovery(dev)) {
1128 			flags |= FTL_MD_CREATE_SHM_NEW;
1129 		}
1130 		break;
1131 	default:
1132 		return FTL_MD_CREATE_HEAP;
1133 	}
1134 
1135 	return flags;
1136 }
1137 
1138 int
1139 ftl_md_destroy_region_flags(struct spdk_ftl_dev *dev, int region_type)
1140 {
1141 	switch (region_type) {
1142 	case FTL_LAYOUT_REGION_TYPE_SB:
1143 	case FTL_LAYOUT_REGION_TYPE_BAND_MD:
1144 	case FTL_LAYOUT_REGION_TYPE_VALID_MAP:
1145 	case FTL_LAYOUT_REGION_TYPE_NVC_MD:
1146 	case FTL_LAYOUT_REGION_TYPE_TRIM_MD:
1147 		if (dev->conf.fast_shutdown) {
1148 			return FTL_MD_DESTROY_SHM_KEEP;
1149 		}
1150 		break;
1151 
1152 	default:
1153 		break;
1154 	}
1155 	return 0;
1156 }
1157 
1158 int
1159 ftl_md_create_shm_flags(struct spdk_ftl_dev *dev)
1160 {
1161 	int flags = FTL_MD_CREATE_SHM;
1162 
1163 	if (!ftl_fast_startup(dev) && !ftl_fast_recovery(dev)) {
1164 		flags |= FTL_MD_CREATE_SHM_NEW;
1165 	}
1166 	return flags;
1167 }
1168 
1169 int
1170 ftl_md_destroy_shm_flags(struct spdk_ftl_dev *dev)
1171 {
1172 	return (dev->conf.fast_shutdown) ? FTL_MD_DESTROY_SHM_KEEP : 0;
1173 }
1174