This source file includes following definitions.
- wc_lock
- wc_unlock
- persistent_memory_claim
- persistent_memory_claim
- persistent_memory_release
- persistent_memory_page
- persistent_memory_page_offset
- persistent_memory_flush_cache
- persistent_memory_invalidate_cache
- sb
- memory_data
- cache_sector
- read_original_sector
- read_seq_count
- clear_seq_count
- write_original_sector_seq_count
- writecache_flush_all_metadata
- writecache_flush_region
- writecache_notify_io
- writecache_wait_for_ios
- ssd_commit_flushed
- writecache_commit_flushed
- writecache_disk_flush
- writecache_find_entry
- writecache_insert_entry
- writecache_unlink
- writecache_add_to_freelist
- writecache_verify_watermark
- writecache_pop_from_freelist
- writecache_free_entry
- writecache_wait_on_freelist
- writecache_poison_lists
- writecache_flush_entry
- writecache_entry_is_committed
- writecache_flush
- writecache_flush_work
- writecache_autocommit_timer
- writecache_schedule_autocommit
- writecache_discard
- writecache_wait_for_writeback
- writecache_suspend
- writecache_alloc_entries
- writecache_read_metadata
- writecache_resume
- process_flush_mesg
- process_flush_on_suspend_mesg
- writecache_message
- bio_copy_block
- writecache_flush_thread
- writecache_offload_bio
- writecache_map
- writecache_end_io
- writecache_iterate_devices
- writecache_io_hints
- writecache_writeback_endio
- writecache_copy_endio
- __writecache_endio_pmem
- __writecache_endio_ssd
- writecache_endio_thread
- wc_add_block
- __writeback_throttle
- __writecache_writeback_pmem
- __writecache_writeback_ssd
- writecache_writeback
- calculate_memory_size
- init_memory
- writecache_dtr
- writecache_ctr
- writecache_status
- dm_writecache_init
- dm_writecache_exit
1
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5
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7
8 #include <linux/device-mapper.h>
9 #include <linux/module.h>
10 #include <linux/init.h>
11 #include <linux/vmalloc.h>
12 #include <linux/kthread.h>
13 #include <linux/dm-io.h>
14 #include <linux/dm-kcopyd.h>
15 #include <linux/dax.h>
16 #include <linux/pfn_t.h>
17 #include <linux/libnvdimm.h>
18
19 #define DM_MSG_PREFIX "writecache"
20
21 #define HIGH_WATERMARK 50
22 #define LOW_WATERMARK 45
23 #define MAX_WRITEBACK_JOBS 0
24 #define ENDIO_LATENCY 16
25 #define WRITEBACK_LATENCY 64
26 #define AUTOCOMMIT_BLOCKS_SSD 65536
27 #define AUTOCOMMIT_BLOCKS_PMEM 64
28 #define AUTOCOMMIT_MSEC 1000
29
30 #define BITMAP_GRANULARITY 65536
31 #if BITMAP_GRANULARITY < PAGE_SIZE
32 #undef BITMAP_GRANULARITY
33 #define BITMAP_GRANULARITY PAGE_SIZE
34 #endif
35
36 #if IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API) && IS_ENABLED(CONFIG_DAX_DRIVER)
37 #define DM_WRITECACHE_HAS_PMEM
38 #endif
39
40 #ifdef DM_WRITECACHE_HAS_PMEM
41 #define pmem_assign(dest, src) \
42 do { \
43 typeof(dest) uniq = (src); \
44 memcpy_flushcache(&(dest), &uniq, sizeof(dest)); \
45 } while (0)
46 #else
47 #define pmem_assign(dest, src) ((dest) = (src))
48 #endif
49
50 #if defined(__HAVE_ARCH_MEMCPY_MCSAFE) && defined(DM_WRITECACHE_HAS_PMEM)
51 #define DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
52 #endif
53
54 #define MEMORY_SUPERBLOCK_MAGIC 0x23489321
55 #define MEMORY_SUPERBLOCK_VERSION 1
56
57 struct wc_memory_entry {
58 __le64 original_sector;
59 __le64 seq_count;
60 };
61
62 struct wc_memory_superblock {
63 union {
64 struct {
65 __le32 magic;
66 __le32 version;
67 __le32 block_size;
68 __le32 pad;
69 __le64 n_blocks;
70 __le64 seq_count;
71 };
72 __le64 padding[8];
73 };
74 struct wc_memory_entry entries[0];
75 };
76
77 struct wc_entry {
78 struct rb_node rb_node;
79 struct list_head lru;
80 unsigned short wc_list_contiguous;
81 bool write_in_progress
82 #if BITS_PER_LONG == 64
83 :1
84 #endif
85 ;
86 unsigned long index
87 #if BITS_PER_LONG == 64
88 :47
89 #endif
90 ;
91 #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
92 uint64_t original_sector;
93 uint64_t seq_count;
94 #endif
95 };
96
97 #ifdef DM_WRITECACHE_HAS_PMEM
98 #define WC_MODE_PMEM(wc) ((wc)->pmem_mode)
99 #define WC_MODE_FUA(wc) ((wc)->writeback_fua)
100 #else
101 #define WC_MODE_PMEM(wc) false
102 #define WC_MODE_FUA(wc) false
103 #endif
104 #define WC_MODE_SORT_FREELIST(wc) (!WC_MODE_PMEM(wc))
105
106 struct dm_writecache {
107 struct mutex lock;
108 struct list_head lru;
109 union {
110 struct list_head freelist;
111 struct {
112 struct rb_root freetree;
113 struct wc_entry *current_free;
114 };
115 };
116 struct rb_root tree;
117
118 size_t freelist_size;
119 size_t writeback_size;
120 size_t freelist_high_watermark;
121 size_t freelist_low_watermark;
122
123 unsigned uncommitted_blocks;
124 unsigned autocommit_blocks;
125 unsigned max_writeback_jobs;
126
127 int error;
128
129 unsigned long autocommit_jiffies;
130 struct timer_list autocommit_timer;
131 struct wait_queue_head freelist_wait;
132
133 atomic_t bio_in_progress[2];
134 struct wait_queue_head bio_in_progress_wait[2];
135
136 struct dm_target *ti;
137 struct dm_dev *dev;
138 struct dm_dev *ssd_dev;
139 sector_t start_sector;
140 void *memory_map;
141 uint64_t memory_map_size;
142 size_t metadata_sectors;
143 size_t n_blocks;
144 uint64_t seq_count;
145 void *block_start;
146 struct wc_entry *entries;
147 unsigned block_size;
148 unsigned char block_size_bits;
149
150 bool pmem_mode:1;
151 bool writeback_fua:1;
152
153 bool overwrote_committed:1;
154 bool memory_vmapped:1;
155
156 bool high_wm_percent_set:1;
157 bool low_wm_percent_set:1;
158 bool max_writeback_jobs_set:1;
159 bool autocommit_blocks_set:1;
160 bool autocommit_time_set:1;
161 bool writeback_fua_set:1;
162 bool flush_on_suspend:1;
163
164 unsigned writeback_all;
165 struct workqueue_struct *writeback_wq;
166 struct work_struct writeback_work;
167 struct work_struct flush_work;
168
169 struct dm_io_client *dm_io;
170
171 raw_spinlock_t endio_list_lock;
172 struct list_head endio_list;
173 struct task_struct *endio_thread;
174
175 struct task_struct *flush_thread;
176 struct bio_list flush_list;
177
178 struct dm_kcopyd_client *dm_kcopyd;
179 unsigned long *dirty_bitmap;
180 unsigned dirty_bitmap_size;
181
182 struct bio_set bio_set;
183 mempool_t copy_pool;
184 };
185
186 #define WB_LIST_INLINE 16
187
188 struct writeback_struct {
189 struct list_head endio_entry;
190 struct dm_writecache *wc;
191 struct wc_entry **wc_list;
192 unsigned wc_list_n;
193 struct wc_entry *wc_list_inline[WB_LIST_INLINE];
194 struct bio bio;
195 };
196
197 struct copy_struct {
198 struct list_head endio_entry;
199 struct dm_writecache *wc;
200 struct wc_entry *e;
201 unsigned n_entries;
202 int error;
203 };
204
205 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(dm_writecache_throttle,
206 "A percentage of time allocated for data copying");
207
208 static void wc_lock(struct dm_writecache *wc)
209 {
210 mutex_lock(&wc->lock);
211 }
212
213 static void wc_unlock(struct dm_writecache *wc)
214 {
215 mutex_unlock(&wc->lock);
216 }
217
218 #ifdef DM_WRITECACHE_HAS_PMEM
219 static int persistent_memory_claim(struct dm_writecache *wc)
220 {
221 int r;
222 loff_t s;
223 long p, da;
224 pfn_t pfn;
225 int id;
226 struct page **pages;
227
228 wc->memory_vmapped = false;
229
230 if (!wc->ssd_dev->dax_dev) {
231 r = -EOPNOTSUPP;
232 goto err1;
233 }
234 s = wc->memory_map_size;
235 p = s >> PAGE_SHIFT;
236 if (!p) {
237 r = -EINVAL;
238 goto err1;
239 }
240 if (p != s >> PAGE_SHIFT) {
241 r = -EOVERFLOW;
242 goto err1;
243 }
244
245 id = dax_read_lock();
246
247 da = dax_direct_access(wc->ssd_dev->dax_dev, 0, p, &wc->memory_map, &pfn);
248 if (da < 0) {
249 wc->memory_map = NULL;
250 r = da;
251 goto err2;
252 }
253 if (!pfn_t_has_page(pfn)) {
254 wc->memory_map = NULL;
255 r = -EOPNOTSUPP;
256 goto err2;
257 }
258 if (da != p) {
259 long i;
260 wc->memory_map = NULL;
261 pages = kvmalloc_array(p, sizeof(struct page *), GFP_KERNEL);
262 if (!pages) {
263 r = -ENOMEM;
264 goto err2;
265 }
266 i = 0;
267 do {
268 long daa;
269 daa = dax_direct_access(wc->ssd_dev->dax_dev, i, p - i,
270 NULL, &pfn);
271 if (daa <= 0) {
272 r = daa ? daa : -EINVAL;
273 goto err3;
274 }
275 if (!pfn_t_has_page(pfn)) {
276 r = -EOPNOTSUPP;
277 goto err3;
278 }
279 while (daa-- && i < p) {
280 pages[i++] = pfn_t_to_page(pfn);
281 pfn.val++;
282 }
283 } while (i < p);
284 wc->memory_map = vmap(pages, p, VM_MAP, PAGE_KERNEL);
285 if (!wc->memory_map) {
286 r = -ENOMEM;
287 goto err3;
288 }
289 kvfree(pages);
290 wc->memory_vmapped = true;
291 }
292
293 dax_read_unlock(id);
294
295 wc->memory_map += (size_t)wc->start_sector << SECTOR_SHIFT;
296 wc->memory_map_size -= (size_t)wc->start_sector << SECTOR_SHIFT;
297
298 return 0;
299 err3:
300 kvfree(pages);
301 err2:
302 dax_read_unlock(id);
303 err1:
304 return r;
305 }
306 #else
307 static int persistent_memory_claim(struct dm_writecache *wc)
308 {
309 BUG();
310 }
311 #endif
312
313 static void persistent_memory_release(struct dm_writecache *wc)
314 {
315 if (wc->memory_vmapped)
316 vunmap(wc->memory_map - ((size_t)wc->start_sector << SECTOR_SHIFT));
317 }
318
319 static struct page *persistent_memory_page(void *addr)
320 {
321 if (is_vmalloc_addr(addr))
322 return vmalloc_to_page(addr);
323 else
324 return virt_to_page(addr);
325 }
326
327 static unsigned persistent_memory_page_offset(void *addr)
328 {
329 return (unsigned long)addr & (PAGE_SIZE - 1);
330 }
331
332 static void persistent_memory_flush_cache(void *ptr, size_t size)
333 {
334 if (is_vmalloc_addr(ptr))
335 flush_kernel_vmap_range(ptr, size);
336 }
337
338 static void persistent_memory_invalidate_cache(void *ptr, size_t size)
339 {
340 if (is_vmalloc_addr(ptr))
341 invalidate_kernel_vmap_range(ptr, size);
342 }
343
344 static struct wc_memory_superblock *sb(struct dm_writecache *wc)
345 {
346 return wc->memory_map;
347 }
348
349 static struct wc_memory_entry *memory_entry(struct dm_writecache *wc, struct wc_entry *e)
350 {
351 return &sb(wc)->entries[e->index];
352 }
353
354 static void *memory_data(struct dm_writecache *wc, struct wc_entry *e)
355 {
356 return (char *)wc->block_start + (e->index << wc->block_size_bits);
357 }
358
359 static sector_t cache_sector(struct dm_writecache *wc, struct wc_entry *e)
360 {
361 return wc->start_sector + wc->metadata_sectors +
362 ((sector_t)e->index << (wc->block_size_bits - SECTOR_SHIFT));
363 }
364
365 static uint64_t read_original_sector(struct dm_writecache *wc, struct wc_entry *e)
366 {
367 #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
368 return e->original_sector;
369 #else
370 return le64_to_cpu(memory_entry(wc, e)->original_sector);
371 #endif
372 }
373
374 static uint64_t read_seq_count(struct dm_writecache *wc, struct wc_entry *e)
375 {
376 #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
377 return e->seq_count;
378 #else
379 return le64_to_cpu(memory_entry(wc, e)->seq_count);
380 #endif
381 }
382
383 static void clear_seq_count(struct dm_writecache *wc, struct wc_entry *e)
384 {
385 #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
386 e->seq_count = -1;
387 #endif
388 pmem_assign(memory_entry(wc, e)->seq_count, cpu_to_le64(-1));
389 }
390
391 static void write_original_sector_seq_count(struct dm_writecache *wc, struct wc_entry *e,
392 uint64_t original_sector, uint64_t seq_count)
393 {
394 struct wc_memory_entry me;
395 #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
396 e->original_sector = original_sector;
397 e->seq_count = seq_count;
398 #endif
399 me.original_sector = cpu_to_le64(original_sector);
400 me.seq_count = cpu_to_le64(seq_count);
401 pmem_assign(*memory_entry(wc, e), me);
402 }
403
404 #define writecache_error(wc, err, msg, arg...) \
405 do { \
406 if (!cmpxchg(&(wc)->error, 0, err)) \
407 DMERR(msg, ##arg); \
408 wake_up(&(wc)->freelist_wait); \
409 } while (0)
410
411 #define writecache_has_error(wc) (unlikely(READ_ONCE((wc)->error)))
412
413 static void writecache_flush_all_metadata(struct dm_writecache *wc)
414 {
415 if (!WC_MODE_PMEM(wc))
416 memset(wc->dirty_bitmap, -1, wc->dirty_bitmap_size);
417 }
418
419 static void writecache_flush_region(struct dm_writecache *wc, void *ptr, size_t size)
420 {
421 if (!WC_MODE_PMEM(wc))
422 __set_bit(((char *)ptr - (char *)wc->memory_map) / BITMAP_GRANULARITY,
423 wc->dirty_bitmap);
424 }
425
426 static void writecache_disk_flush(struct dm_writecache *wc, struct dm_dev *dev);
427
428 struct io_notify {
429 struct dm_writecache *wc;
430 struct completion c;
431 atomic_t count;
432 };
433
434 static void writecache_notify_io(unsigned long error, void *context)
435 {
436 struct io_notify *endio = context;
437
438 if (unlikely(error != 0))
439 writecache_error(endio->wc, -EIO, "error writing metadata");
440 BUG_ON(atomic_read(&endio->count) <= 0);
441 if (atomic_dec_and_test(&endio->count))
442 complete(&endio->c);
443 }
444
445 static void writecache_wait_for_ios(struct dm_writecache *wc, int direction)
446 {
447 wait_event(wc->bio_in_progress_wait[direction],
448 !atomic_read(&wc->bio_in_progress[direction]));
449 }
450
451 static void ssd_commit_flushed(struct dm_writecache *wc, bool wait_for_ios)
452 {
453 struct dm_io_region region;
454 struct dm_io_request req;
455 struct io_notify endio = {
456 wc,
457 COMPLETION_INITIALIZER_ONSTACK(endio.c),
458 ATOMIC_INIT(1),
459 };
460 unsigned bitmap_bits = wc->dirty_bitmap_size * 8;
461 unsigned i = 0;
462
463 while (1) {
464 unsigned j;
465 i = find_next_bit(wc->dirty_bitmap, bitmap_bits, i);
466 if (unlikely(i == bitmap_bits))
467 break;
468 j = find_next_zero_bit(wc->dirty_bitmap, bitmap_bits, i);
469
470 region.bdev = wc->ssd_dev->bdev;
471 region.sector = (sector_t)i * (BITMAP_GRANULARITY >> SECTOR_SHIFT);
472 region.count = (sector_t)(j - i) * (BITMAP_GRANULARITY >> SECTOR_SHIFT);
473
474 if (unlikely(region.sector >= wc->metadata_sectors))
475 break;
476 if (unlikely(region.sector + region.count > wc->metadata_sectors))
477 region.count = wc->metadata_sectors - region.sector;
478
479 region.sector += wc->start_sector;
480 atomic_inc(&endio.count);
481 req.bi_op = REQ_OP_WRITE;
482 req.bi_op_flags = REQ_SYNC;
483 req.mem.type = DM_IO_VMA;
484 req.mem.ptr.vma = (char *)wc->memory_map + (size_t)i * BITMAP_GRANULARITY;
485 req.client = wc->dm_io;
486 req.notify.fn = writecache_notify_io;
487 req.notify.context = &endio;
488
489
490 (void) dm_io(&req, 1, ®ion, NULL);
491 i = j;
492 }
493
494 writecache_notify_io(0, &endio);
495 wait_for_completion_io(&endio.c);
496
497 if (wait_for_ios)
498 writecache_wait_for_ios(wc, WRITE);
499
500 writecache_disk_flush(wc, wc->ssd_dev);
501
502 memset(wc->dirty_bitmap, 0, wc->dirty_bitmap_size);
503 }
504
505 static void writecache_commit_flushed(struct dm_writecache *wc, bool wait_for_ios)
506 {
507 if (WC_MODE_PMEM(wc))
508 wmb();
509 else
510 ssd_commit_flushed(wc, wait_for_ios);
511 }
512
513 static void writecache_disk_flush(struct dm_writecache *wc, struct dm_dev *dev)
514 {
515 int r;
516 struct dm_io_region region;
517 struct dm_io_request req;
518
519 region.bdev = dev->bdev;
520 region.sector = 0;
521 region.count = 0;
522 req.bi_op = REQ_OP_WRITE;
523 req.bi_op_flags = REQ_PREFLUSH;
524 req.mem.type = DM_IO_KMEM;
525 req.mem.ptr.addr = NULL;
526 req.client = wc->dm_io;
527 req.notify.fn = NULL;
528
529 r = dm_io(&req, 1, ®ion, NULL);
530 if (unlikely(r))
531 writecache_error(wc, r, "error flushing metadata: %d", r);
532 }
533
534 #define WFE_RETURN_FOLLOWING 1
535 #define WFE_LOWEST_SEQ 2
536
537 static struct wc_entry *writecache_find_entry(struct dm_writecache *wc,
538 uint64_t block, int flags)
539 {
540 struct wc_entry *e;
541 struct rb_node *node = wc->tree.rb_node;
542
543 if (unlikely(!node))
544 return NULL;
545
546 while (1) {
547 e = container_of(node, struct wc_entry, rb_node);
548 if (read_original_sector(wc, e) == block)
549 break;
550
551 node = (read_original_sector(wc, e) >= block ?
552 e->rb_node.rb_left : e->rb_node.rb_right);
553 if (unlikely(!node)) {
554 if (!(flags & WFE_RETURN_FOLLOWING))
555 return NULL;
556 if (read_original_sector(wc, e) >= block) {
557 return e;
558 } else {
559 node = rb_next(&e->rb_node);
560 if (unlikely(!node))
561 return NULL;
562 e = container_of(node, struct wc_entry, rb_node);
563 return e;
564 }
565 }
566 }
567
568 while (1) {
569 struct wc_entry *e2;
570 if (flags & WFE_LOWEST_SEQ)
571 node = rb_prev(&e->rb_node);
572 else
573 node = rb_next(&e->rb_node);
574 if (unlikely(!node))
575 return e;
576 e2 = container_of(node, struct wc_entry, rb_node);
577 if (read_original_sector(wc, e2) != block)
578 return e;
579 e = e2;
580 }
581 }
582
583 static void writecache_insert_entry(struct dm_writecache *wc, struct wc_entry *ins)
584 {
585 struct wc_entry *e;
586 struct rb_node **node = &wc->tree.rb_node, *parent = NULL;
587
588 while (*node) {
589 e = container_of(*node, struct wc_entry, rb_node);
590 parent = &e->rb_node;
591 if (read_original_sector(wc, e) > read_original_sector(wc, ins))
592 node = &parent->rb_left;
593 else
594 node = &parent->rb_right;
595 }
596 rb_link_node(&ins->rb_node, parent, node);
597 rb_insert_color(&ins->rb_node, &wc->tree);
598 list_add(&ins->lru, &wc->lru);
599 }
600
601 static void writecache_unlink(struct dm_writecache *wc, struct wc_entry *e)
602 {
603 list_del(&e->lru);
604 rb_erase(&e->rb_node, &wc->tree);
605 }
606
607 static void writecache_add_to_freelist(struct dm_writecache *wc, struct wc_entry *e)
608 {
609 if (WC_MODE_SORT_FREELIST(wc)) {
610 struct rb_node **node = &wc->freetree.rb_node, *parent = NULL;
611 if (unlikely(!*node))
612 wc->current_free = e;
613 while (*node) {
614 parent = *node;
615 if (&e->rb_node < *node)
616 node = &parent->rb_left;
617 else
618 node = &parent->rb_right;
619 }
620 rb_link_node(&e->rb_node, parent, node);
621 rb_insert_color(&e->rb_node, &wc->freetree);
622 } else {
623 list_add_tail(&e->lru, &wc->freelist);
624 }
625 wc->freelist_size++;
626 }
627
628 static inline void writecache_verify_watermark(struct dm_writecache *wc)
629 {
630 if (unlikely(wc->freelist_size + wc->writeback_size <= wc->freelist_high_watermark))
631 queue_work(wc->writeback_wq, &wc->writeback_work);
632 }
633
634 static struct wc_entry *writecache_pop_from_freelist(struct dm_writecache *wc)
635 {
636 struct wc_entry *e;
637
638 if (WC_MODE_SORT_FREELIST(wc)) {
639 struct rb_node *next;
640 if (unlikely(!wc->current_free))
641 return NULL;
642 e = wc->current_free;
643 next = rb_next(&e->rb_node);
644 rb_erase(&e->rb_node, &wc->freetree);
645 if (unlikely(!next))
646 next = rb_first(&wc->freetree);
647 wc->current_free = next ? container_of(next, struct wc_entry, rb_node) : NULL;
648 } else {
649 if (unlikely(list_empty(&wc->freelist)))
650 return NULL;
651 e = container_of(wc->freelist.next, struct wc_entry, lru);
652 list_del(&e->lru);
653 }
654 wc->freelist_size--;
655
656 writecache_verify_watermark(wc);
657
658 return e;
659 }
660
661 static void writecache_free_entry(struct dm_writecache *wc, struct wc_entry *e)
662 {
663 writecache_unlink(wc, e);
664 writecache_add_to_freelist(wc, e);
665 clear_seq_count(wc, e);
666 writecache_flush_region(wc, memory_entry(wc, e), sizeof(struct wc_memory_entry));
667 if (unlikely(waitqueue_active(&wc->freelist_wait)))
668 wake_up(&wc->freelist_wait);
669 }
670
671 static void writecache_wait_on_freelist(struct dm_writecache *wc)
672 {
673 DEFINE_WAIT(wait);
674
675 prepare_to_wait(&wc->freelist_wait, &wait, TASK_UNINTERRUPTIBLE);
676 wc_unlock(wc);
677 io_schedule();
678 finish_wait(&wc->freelist_wait, &wait);
679 wc_lock(wc);
680 }
681
682 static void writecache_poison_lists(struct dm_writecache *wc)
683 {
684
685
686
687 memset(&wc->tree, -1, sizeof wc->tree);
688 wc->lru.next = LIST_POISON1;
689 wc->lru.prev = LIST_POISON2;
690 wc->freelist.next = LIST_POISON1;
691 wc->freelist.prev = LIST_POISON2;
692 }
693
694 static void writecache_flush_entry(struct dm_writecache *wc, struct wc_entry *e)
695 {
696 writecache_flush_region(wc, memory_entry(wc, e), sizeof(struct wc_memory_entry));
697 if (WC_MODE_PMEM(wc))
698 writecache_flush_region(wc, memory_data(wc, e), wc->block_size);
699 }
700
701 static bool writecache_entry_is_committed(struct dm_writecache *wc, struct wc_entry *e)
702 {
703 return read_seq_count(wc, e) < wc->seq_count;
704 }
705
706 static void writecache_flush(struct dm_writecache *wc)
707 {
708 struct wc_entry *e, *e2;
709 bool need_flush_after_free;
710
711 wc->uncommitted_blocks = 0;
712 del_timer(&wc->autocommit_timer);
713
714 if (list_empty(&wc->lru))
715 return;
716
717 e = container_of(wc->lru.next, struct wc_entry, lru);
718 if (writecache_entry_is_committed(wc, e)) {
719 if (wc->overwrote_committed) {
720 writecache_wait_for_ios(wc, WRITE);
721 writecache_disk_flush(wc, wc->ssd_dev);
722 wc->overwrote_committed = false;
723 }
724 return;
725 }
726 while (1) {
727 writecache_flush_entry(wc, e);
728 if (unlikely(e->lru.next == &wc->lru))
729 break;
730 e2 = container_of(e->lru.next, struct wc_entry, lru);
731 if (writecache_entry_is_committed(wc, e2))
732 break;
733 e = e2;
734 cond_resched();
735 }
736 writecache_commit_flushed(wc, true);
737
738 wc->seq_count++;
739 pmem_assign(sb(wc)->seq_count, cpu_to_le64(wc->seq_count));
740 writecache_flush_region(wc, &sb(wc)->seq_count, sizeof sb(wc)->seq_count);
741 writecache_commit_flushed(wc, false);
742
743 wc->overwrote_committed = false;
744
745 need_flush_after_free = false;
746 while (1) {
747
748 struct rb_node *rb_node = rb_prev(&e->rb_node);
749
750 if (rb_node) {
751 e2 = container_of(rb_node, struct wc_entry, rb_node);
752 if (read_original_sector(wc, e2) == read_original_sector(wc, e) &&
753 likely(!e2->write_in_progress)) {
754 writecache_free_entry(wc, e2);
755 need_flush_after_free = true;
756 }
757 }
758 if (unlikely(e->lru.prev == &wc->lru))
759 break;
760 e = container_of(e->lru.prev, struct wc_entry, lru);
761 cond_resched();
762 }
763
764 if (need_flush_after_free)
765 writecache_commit_flushed(wc, false);
766 }
767
768 static void writecache_flush_work(struct work_struct *work)
769 {
770 struct dm_writecache *wc = container_of(work, struct dm_writecache, flush_work);
771
772 wc_lock(wc);
773 writecache_flush(wc);
774 wc_unlock(wc);
775 }
776
777 static void writecache_autocommit_timer(struct timer_list *t)
778 {
779 struct dm_writecache *wc = from_timer(wc, t, autocommit_timer);
780 if (!writecache_has_error(wc))
781 queue_work(wc->writeback_wq, &wc->flush_work);
782 }
783
784 static void writecache_schedule_autocommit(struct dm_writecache *wc)
785 {
786 if (!timer_pending(&wc->autocommit_timer))
787 mod_timer(&wc->autocommit_timer, jiffies + wc->autocommit_jiffies);
788 }
789
790 static void writecache_discard(struct dm_writecache *wc, sector_t start, sector_t end)
791 {
792 struct wc_entry *e;
793 bool discarded_something = false;
794
795 e = writecache_find_entry(wc, start, WFE_RETURN_FOLLOWING | WFE_LOWEST_SEQ);
796 if (unlikely(!e))
797 return;
798
799 while (read_original_sector(wc, e) < end) {
800 struct rb_node *node = rb_next(&e->rb_node);
801
802 if (likely(!e->write_in_progress)) {
803 if (!discarded_something) {
804 writecache_wait_for_ios(wc, READ);
805 writecache_wait_for_ios(wc, WRITE);
806 discarded_something = true;
807 }
808 writecache_free_entry(wc, e);
809 }
810
811 if (unlikely(!node))
812 break;
813
814 e = container_of(node, struct wc_entry, rb_node);
815 }
816
817 if (discarded_something)
818 writecache_commit_flushed(wc, false);
819 }
820
821 static bool writecache_wait_for_writeback(struct dm_writecache *wc)
822 {
823 if (wc->writeback_size) {
824 writecache_wait_on_freelist(wc);
825 return true;
826 }
827 return false;
828 }
829
830 static void writecache_suspend(struct dm_target *ti)
831 {
832 struct dm_writecache *wc = ti->private;
833 bool flush_on_suspend;
834
835 del_timer_sync(&wc->autocommit_timer);
836
837 wc_lock(wc);
838 writecache_flush(wc);
839 flush_on_suspend = wc->flush_on_suspend;
840 if (flush_on_suspend) {
841 wc->flush_on_suspend = false;
842 wc->writeback_all++;
843 queue_work(wc->writeback_wq, &wc->writeback_work);
844 }
845 wc_unlock(wc);
846
847 drain_workqueue(wc->writeback_wq);
848
849 wc_lock(wc);
850 if (flush_on_suspend)
851 wc->writeback_all--;
852 while (writecache_wait_for_writeback(wc));
853
854 if (WC_MODE_PMEM(wc))
855 persistent_memory_flush_cache(wc->memory_map, wc->memory_map_size);
856
857 writecache_poison_lists(wc);
858
859 wc_unlock(wc);
860 }
861
862 static int writecache_alloc_entries(struct dm_writecache *wc)
863 {
864 size_t b;
865
866 if (wc->entries)
867 return 0;
868 wc->entries = vmalloc(array_size(sizeof(struct wc_entry), wc->n_blocks));
869 if (!wc->entries)
870 return -ENOMEM;
871 for (b = 0; b < wc->n_blocks; b++) {
872 struct wc_entry *e = &wc->entries[b];
873 e->index = b;
874 e->write_in_progress = false;
875 cond_resched();
876 }
877
878 return 0;
879 }
880
881 static int writecache_read_metadata(struct dm_writecache *wc, sector_t n_sectors)
882 {
883 struct dm_io_region region;
884 struct dm_io_request req;
885
886 region.bdev = wc->ssd_dev->bdev;
887 region.sector = wc->start_sector;
888 region.count = n_sectors;
889 req.bi_op = REQ_OP_READ;
890 req.bi_op_flags = REQ_SYNC;
891 req.mem.type = DM_IO_VMA;
892 req.mem.ptr.vma = (char *)wc->memory_map;
893 req.client = wc->dm_io;
894 req.notify.fn = NULL;
895
896 return dm_io(&req, 1, ®ion, NULL);
897 }
898
899 static void writecache_resume(struct dm_target *ti)
900 {
901 struct dm_writecache *wc = ti->private;
902 size_t b;
903 bool need_flush = false;
904 __le64 sb_seq_count;
905 int r;
906
907 wc_lock(wc);
908
909 if (WC_MODE_PMEM(wc)) {
910 persistent_memory_invalidate_cache(wc->memory_map, wc->memory_map_size);
911 } else {
912 r = writecache_read_metadata(wc, wc->metadata_sectors);
913 if (r) {
914 size_t sb_entries_offset;
915 writecache_error(wc, r, "unable to read metadata: %d", r);
916 sb_entries_offset = offsetof(struct wc_memory_superblock, entries);
917 memset((char *)wc->memory_map + sb_entries_offset, -1,
918 (wc->metadata_sectors << SECTOR_SHIFT) - sb_entries_offset);
919 }
920 }
921
922 wc->tree = RB_ROOT;
923 INIT_LIST_HEAD(&wc->lru);
924 if (WC_MODE_SORT_FREELIST(wc)) {
925 wc->freetree = RB_ROOT;
926 wc->current_free = NULL;
927 } else {
928 INIT_LIST_HEAD(&wc->freelist);
929 }
930 wc->freelist_size = 0;
931
932 r = memcpy_mcsafe(&sb_seq_count, &sb(wc)->seq_count, sizeof(uint64_t));
933 if (r) {
934 writecache_error(wc, r, "hardware memory error when reading superblock: %d", r);
935 sb_seq_count = cpu_to_le64(0);
936 }
937 wc->seq_count = le64_to_cpu(sb_seq_count);
938
939 #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
940 for (b = 0; b < wc->n_blocks; b++) {
941 struct wc_entry *e = &wc->entries[b];
942 struct wc_memory_entry wme;
943 if (writecache_has_error(wc)) {
944 e->original_sector = -1;
945 e->seq_count = -1;
946 continue;
947 }
948 r = memcpy_mcsafe(&wme, memory_entry(wc, e), sizeof(struct wc_memory_entry));
949 if (r) {
950 writecache_error(wc, r, "hardware memory error when reading metadata entry %lu: %d",
951 (unsigned long)b, r);
952 e->original_sector = -1;
953 e->seq_count = -1;
954 } else {
955 e->original_sector = le64_to_cpu(wme.original_sector);
956 e->seq_count = le64_to_cpu(wme.seq_count);
957 }
958 cond_resched();
959 }
960 #endif
961 for (b = 0; b < wc->n_blocks; b++) {
962 struct wc_entry *e = &wc->entries[b];
963 if (!writecache_entry_is_committed(wc, e)) {
964 if (read_seq_count(wc, e) != -1) {
965 erase_this:
966 clear_seq_count(wc, e);
967 need_flush = true;
968 }
969 writecache_add_to_freelist(wc, e);
970 } else {
971 struct wc_entry *old;
972
973 old = writecache_find_entry(wc, read_original_sector(wc, e), 0);
974 if (!old) {
975 writecache_insert_entry(wc, e);
976 } else {
977 if (read_seq_count(wc, old) == read_seq_count(wc, e)) {
978 writecache_error(wc, -EINVAL,
979 "two identical entries, position %llu, sector %llu, sequence %llu",
980 (unsigned long long)b, (unsigned long long)read_original_sector(wc, e),
981 (unsigned long long)read_seq_count(wc, e));
982 }
983 if (read_seq_count(wc, old) > read_seq_count(wc, e)) {
984 goto erase_this;
985 } else {
986 writecache_free_entry(wc, old);
987 writecache_insert_entry(wc, e);
988 need_flush = true;
989 }
990 }
991 }
992 cond_resched();
993 }
994
995 if (need_flush) {
996 writecache_flush_all_metadata(wc);
997 writecache_commit_flushed(wc, false);
998 }
999
1000 writecache_verify_watermark(wc);
1001
1002 wc_unlock(wc);
1003 }
1004
1005 static int process_flush_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
1006 {
1007 if (argc != 1)
1008 return -EINVAL;
1009
1010 wc_lock(wc);
1011 if (dm_suspended(wc->ti)) {
1012 wc_unlock(wc);
1013 return -EBUSY;
1014 }
1015 if (writecache_has_error(wc)) {
1016 wc_unlock(wc);
1017 return -EIO;
1018 }
1019
1020 writecache_flush(wc);
1021 wc->writeback_all++;
1022 queue_work(wc->writeback_wq, &wc->writeback_work);
1023 wc_unlock(wc);
1024
1025 flush_workqueue(wc->writeback_wq);
1026
1027 wc_lock(wc);
1028 wc->writeback_all--;
1029 if (writecache_has_error(wc)) {
1030 wc_unlock(wc);
1031 return -EIO;
1032 }
1033 wc_unlock(wc);
1034
1035 return 0;
1036 }
1037
1038 static int process_flush_on_suspend_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
1039 {
1040 if (argc != 1)
1041 return -EINVAL;
1042
1043 wc_lock(wc);
1044 wc->flush_on_suspend = true;
1045 wc_unlock(wc);
1046
1047 return 0;
1048 }
1049
1050 static int writecache_message(struct dm_target *ti, unsigned argc, char **argv,
1051 char *result, unsigned maxlen)
1052 {
1053 int r = -EINVAL;
1054 struct dm_writecache *wc = ti->private;
1055
1056 if (!strcasecmp(argv[0], "flush"))
1057 r = process_flush_mesg(argc, argv, wc);
1058 else if (!strcasecmp(argv[0], "flush_on_suspend"))
1059 r = process_flush_on_suspend_mesg(argc, argv, wc);
1060 else
1061 DMERR("unrecognised message received: %s", argv[0]);
1062
1063 return r;
1064 }
1065
1066 static void bio_copy_block(struct dm_writecache *wc, struct bio *bio, void *data)
1067 {
1068 void *buf;
1069 unsigned long flags;
1070 unsigned size;
1071 int rw = bio_data_dir(bio);
1072 unsigned remaining_size = wc->block_size;
1073
1074 do {
1075 struct bio_vec bv = bio_iter_iovec(bio, bio->bi_iter);
1076 buf = bvec_kmap_irq(&bv, &flags);
1077 size = bv.bv_len;
1078 if (unlikely(size > remaining_size))
1079 size = remaining_size;
1080
1081 if (rw == READ) {
1082 int r;
1083 r = memcpy_mcsafe(buf, data, size);
1084 flush_dcache_page(bio_page(bio));
1085 if (unlikely(r)) {
1086 writecache_error(wc, r, "hardware memory error when reading data: %d", r);
1087 bio->bi_status = BLK_STS_IOERR;
1088 }
1089 } else {
1090 flush_dcache_page(bio_page(bio));
1091 memcpy_flushcache(data, buf, size);
1092 }
1093
1094 bvec_kunmap_irq(buf, &flags);
1095
1096 data = (char *)data + size;
1097 remaining_size -= size;
1098 bio_advance(bio, size);
1099 } while (unlikely(remaining_size));
1100 }
1101
1102 static int writecache_flush_thread(void *data)
1103 {
1104 struct dm_writecache *wc = data;
1105
1106 while (1) {
1107 struct bio *bio;
1108
1109 wc_lock(wc);
1110 bio = bio_list_pop(&wc->flush_list);
1111 if (!bio) {
1112 set_current_state(TASK_INTERRUPTIBLE);
1113 wc_unlock(wc);
1114
1115 if (unlikely(kthread_should_stop())) {
1116 set_current_state(TASK_RUNNING);
1117 break;
1118 }
1119
1120 schedule();
1121 continue;
1122 }
1123
1124 if (bio_op(bio) == REQ_OP_DISCARD) {
1125 writecache_discard(wc, bio->bi_iter.bi_sector,
1126 bio_end_sector(bio));
1127 wc_unlock(wc);
1128 bio_set_dev(bio, wc->dev->bdev);
1129 generic_make_request(bio);
1130 } else {
1131 writecache_flush(wc);
1132 wc_unlock(wc);
1133 if (writecache_has_error(wc))
1134 bio->bi_status = BLK_STS_IOERR;
1135 bio_endio(bio);
1136 }
1137 }
1138
1139 return 0;
1140 }
1141
1142 static void writecache_offload_bio(struct dm_writecache *wc, struct bio *bio)
1143 {
1144 if (bio_list_empty(&wc->flush_list))
1145 wake_up_process(wc->flush_thread);
1146 bio_list_add(&wc->flush_list, bio);
1147 }
1148
1149 static int writecache_map(struct dm_target *ti, struct bio *bio)
1150 {
1151 struct wc_entry *e;
1152 struct dm_writecache *wc = ti->private;
1153
1154 bio->bi_private = NULL;
1155
1156 wc_lock(wc);
1157
1158 if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
1159 if (writecache_has_error(wc))
1160 goto unlock_error;
1161 if (WC_MODE_PMEM(wc)) {
1162 writecache_flush(wc);
1163 if (writecache_has_error(wc))
1164 goto unlock_error;
1165 goto unlock_submit;
1166 } else {
1167 writecache_offload_bio(wc, bio);
1168 goto unlock_return;
1169 }
1170 }
1171
1172 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
1173
1174 if (unlikely((((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) &
1175 (wc->block_size / 512 - 1)) != 0)) {
1176 DMERR("I/O is not aligned, sector %llu, size %u, block size %u",
1177 (unsigned long long)bio->bi_iter.bi_sector,
1178 bio->bi_iter.bi_size, wc->block_size);
1179 goto unlock_error;
1180 }
1181
1182 if (unlikely(bio_op(bio) == REQ_OP_DISCARD)) {
1183 if (writecache_has_error(wc))
1184 goto unlock_error;
1185 if (WC_MODE_PMEM(wc)) {
1186 writecache_discard(wc, bio->bi_iter.bi_sector, bio_end_sector(bio));
1187 goto unlock_remap_origin;
1188 } else {
1189 writecache_offload_bio(wc, bio);
1190 goto unlock_return;
1191 }
1192 }
1193
1194 if (bio_data_dir(bio) == READ) {
1195 read_next_block:
1196 e = writecache_find_entry(wc, bio->bi_iter.bi_sector, WFE_RETURN_FOLLOWING);
1197 if (e && read_original_sector(wc, e) == bio->bi_iter.bi_sector) {
1198 if (WC_MODE_PMEM(wc)) {
1199 bio_copy_block(wc, bio, memory_data(wc, e));
1200 if (bio->bi_iter.bi_size)
1201 goto read_next_block;
1202 goto unlock_submit;
1203 } else {
1204 dm_accept_partial_bio(bio, wc->block_size >> SECTOR_SHIFT);
1205 bio_set_dev(bio, wc->ssd_dev->bdev);
1206 bio->bi_iter.bi_sector = cache_sector(wc, e);
1207 if (!writecache_entry_is_committed(wc, e))
1208 writecache_wait_for_ios(wc, WRITE);
1209 goto unlock_remap;
1210 }
1211 } else {
1212 if (e) {
1213 sector_t next_boundary =
1214 read_original_sector(wc, e) - bio->bi_iter.bi_sector;
1215 if (next_boundary < bio->bi_iter.bi_size >> SECTOR_SHIFT) {
1216 dm_accept_partial_bio(bio, next_boundary);
1217 }
1218 }
1219 goto unlock_remap_origin;
1220 }
1221 } else {
1222 do {
1223 if (writecache_has_error(wc))
1224 goto unlock_error;
1225 e = writecache_find_entry(wc, bio->bi_iter.bi_sector, 0);
1226 if (e) {
1227 if (!writecache_entry_is_committed(wc, e))
1228 goto bio_copy;
1229 if (!WC_MODE_PMEM(wc) && !e->write_in_progress) {
1230 wc->overwrote_committed = true;
1231 goto bio_copy;
1232 }
1233 }
1234 e = writecache_pop_from_freelist(wc);
1235 if (unlikely(!e)) {
1236 writecache_wait_on_freelist(wc);
1237 continue;
1238 }
1239 write_original_sector_seq_count(wc, e, bio->bi_iter.bi_sector, wc->seq_count);
1240 writecache_insert_entry(wc, e);
1241 wc->uncommitted_blocks++;
1242 bio_copy:
1243 if (WC_MODE_PMEM(wc)) {
1244 bio_copy_block(wc, bio, memory_data(wc, e));
1245 } else {
1246 dm_accept_partial_bio(bio, wc->block_size >> SECTOR_SHIFT);
1247 bio_set_dev(bio, wc->ssd_dev->bdev);
1248 bio->bi_iter.bi_sector = cache_sector(wc, e);
1249 if (unlikely(wc->uncommitted_blocks >= wc->autocommit_blocks)) {
1250 wc->uncommitted_blocks = 0;
1251 queue_work(wc->writeback_wq, &wc->flush_work);
1252 } else {
1253 writecache_schedule_autocommit(wc);
1254 }
1255 goto unlock_remap;
1256 }
1257 } while (bio->bi_iter.bi_size);
1258
1259 if (unlikely(bio->bi_opf & REQ_FUA ||
1260 wc->uncommitted_blocks >= wc->autocommit_blocks))
1261 writecache_flush(wc);
1262 else
1263 writecache_schedule_autocommit(wc);
1264 goto unlock_submit;
1265 }
1266
1267 unlock_remap_origin:
1268 bio_set_dev(bio, wc->dev->bdev);
1269 wc_unlock(wc);
1270 return DM_MAPIO_REMAPPED;
1271
1272 unlock_remap:
1273
1274 bio->bi_private = (void *)1;
1275 atomic_inc(&wc->bio_in_progress[bio_data_dir(bio)]);
1276 wc_unlock(wc);
1277 return DM_MAPIO_REMAPPED;
1278
1279 unlock_submit:
1280 wc_unlock(wc);
1281 bio_endio(bio);
1282 return DM_MAPIO_SUBMITTED;
1283
1284 unlock_return:
1285 wc_unlock(wc);
1286 return DM_MAPIO_SUBMITTED;
1287
1288 unlock_error:
1289 wc_unlock(wc);
1290 bio_io_error(bio);
1291 return DM_MAPIO_SUBMITTED;
1292 }
1293
1294 static int writecache_end_io(struct dm_target *ti, struct bio *bio, blk_status_t *status)
1295 {
1296 struct dm_writecache *wc = ti->private;
1297
1298 if (bio->bi_private != NULL) {
1299 int dir = bio_data_dir(bio);
1300 if (atomic_dec_and_test(&wc->bio_in_progress[dir]))
1301 if (unlikely(waitqueue_active(&wc->bio_in_progress_wait[dir])))
1302 wake_up(&wc->bio_in_progress_wait[dir]);
1303 }
1304 return 0;
1305 }
1306
1307 static int writecache_iterate_devices(struct dm_target *ti,
1308 iterate_devices_callout_fn fn, void *data)
1309 {
1310 struct dm_writecache *wc = ti->private;
1311
1312 return fn(ti, wc->dev, 0, ti->len, data);
1313 }
1314
1315 static void writecache_io_hints(struct dm_target *ti, struct queue_limits *limits)
1316 {
1317 struct dm_writecache *wc = ti->private;
1318
1319 if (limits->logical_block_size < wc->block_size)
1320 limits->logical_block_size = wc->block_size;
1321
1322 if (limits->physical_block_size < wc->block_size)
1323 limits->physical_block_size = wc->block_size;
1324
1325 if (limits->io_min < wc->block_size)
1326 limits->io_min = wc->block_size;
1327 }
1328
1329
1330 static void writecache_writeback_endio(struct bio *bio)
1331 {
1332 struct writeback_struct *wb = container_of(bio, struct writeback_struct, bio);
1333 struct dm_writecache *wc = wb->wc;
1334 unsigned long flags;
1335
1336 raw_spin_lock_irqsave(&wc->endio_list_lock, flags);
1337 if (unlikely(list_empty(&wc->endio_list)))
1338 wake_up_process(wc->endio_thread);
1339 list_add_tail(&wb->endio_entry, &wc->endio_list);
1340 raw_spin_unlock_irqrestore(&wc->endio_list_lock, flags);
1341 }
1342
1343 static void writecache_copy_endio(int read_err, unsigned long write_err, void *ptr)
1344 {
1345 struct copy_struct *c = ptr;
1346 struct dm_writecache *wc = c->wc;
1347
1348 c->error = likely(!(read_err | write_err)) ? 0 : -EIO;
1349
1350 raw_spin_lock_irq(&wc->endio_list_lock);
1351 if (unlikely(list_empty(&wc->endio_list)))
1352 wake_up_process(wc->endio_thread);
1353 list_add_tail(&c->endio_entry, &wc->endio_list);
1354 raw_spin_unlock_irq(&wc->endio_list_lock);
1355 }
1356
1357 static void __writecache_endio_pmem(struct dm_writecache *wc, struct list_head *list)
1358 {
1359 unsigned i;
1360 struct writeback_struct *wb;
1361 struct wc_entry *e;
1362 unsigned long n_walked = 0;
1363
1364 do {
1365 wb = list_entry(list->next, struct writeback_struct, endio_entry);
1366 list_del(&wb->endio_entry);
1367
1368 if (unlikely(wb->bio.bi_status != BLK_STS_OK))
1369 writecache_error(wc, blk_status_to_errno(wb->bio.bi_status),
1370 "write error %d", wb->bio.bi_status);
1371 i = 0;
1372 do {
1373 e = wb->wc_list[i];
1374 BUG_ON(!e->write_in_progress);
1375 e->write_in_progress = false;
1376 INIT_LIST_HEAD(&e->lru);
1377 if (!writecache_has_error(wc))
1378 writecache_free_entry(wc, e);
1379 BUG_ON(!wc->writeback_size);
1380 wc->writeback_size--;
1381 n_walked++;
1382 if (unlikely(n_walked >= ENDIO_LATENCY)) {
1383 writecache_commit_flushed(wc, false);
1384 wc_unlock(wc);
1385 wc_lock(wc);
1386 n_walked = 0;
1387 }
1388 } while (++i < wb->wc_list_n);
1389
1390 if (wb->wc_list != wb->wc_list_inline)
1391 kfree(wb->wc_list);
1392 bio_put(&wb->bio);
1393 } while (!list_empty(list));
1394 }
1395
1396 static void __writecache_endio_ssd(struct dm_writecache *wc, struct list_head *list)
1397 {
1398 struct copy_struct *c;
1399 struct wc_entry *e;
1400
1401 do {
1402 c = list_entry(list->next, struct copy_struct, endio_entry);
1403 list_del(&c->endio_entry);
1404
1405 if (unlikely(c->error))
1406 writecache_error(wc, c->error, "copy error");
1407
1408 e = c->e;
1409 do {
1410 BUG_ON(!e->write_in_progress);
1411 e->write_in_progress = false;
1412 INIT_LIST_HEAD(&e->lru);
1413 if (!writecache_has_error(wc))
1414 writecache_free_entry(wc, e);
1415
1416 BUG_ON(!wc->writeback_size);
1417 wc->writeback_size--;
1418 e++;
1419 } while (--c->n_entries);
1420 mempool_free(c, &wc->copy_pool);
1421 } while (!list_empty(list));
1422 }
1423
1424 static int writecache_endio_thread(void *data)
1425 {
1426 struct dm_writecache *wc = data;
1427
1428 while (1) {
1429 struct list_head list;
1430
1431 raw_spin_lock_irq(&wc->endio_list_lock);
1432 if (!list_empty(&wc->endio_list))
1433 goto pop_from_list;
1434 set_current_state(TASK_INTERRUPTIBLE);
1435 raw_spin_unlock_irq(&wc->endio_list_lock);
1436
1437 if (unlikely(kthread_should_stop())) {
1438 set_current_state(TASK_RUNNING);
1439 break;
1440 }
1441
1442 schedule();
1443
1444 continue;
1445
1446 pop_from_list:
1447 list = wc->endio_list;
1448 list.next->prev = list.prev->next = &list;
1449 INIT_LIST_HEAD(&wc->endio_list);
1450 raw_spin_unlock_irq(&wc->endio_list_lock);
1451
1452 if (!WC_MODE_FUA(wc))
1453 writecache_disk_flush(wc, wc->dev);
1454
1455 wc_lock(wc);
1456
1457 if (WC_MODE_PMEM(wc)) {
1458 __writecache_endio_pmem(wc, &list);
1459 } else {
1460 __writecache_endio_ssd(wc, &list);
1461 writecache_wait_for_ios(wc, READ);
1462 }
1463
1464 writecache_commit_flushed(wc, false);
1465
1466 wc_unlock(wc);
1467 }
1468
1469 return 0;
1470 }
1471
1472 static bool wc_add_block(struct writeback_struct *wb, struct wc_entry *e, gfp_t gfp)
1473 {
1474 struct dm_writecache *wc = wb->wc;
1475 unsigned block_size = wc->block_size;
1476 void *address = memory_data(wc, e);
1477
1478 persistent_memory_flush_cache(address, block_size);
1479 return bio_add_page(&wb->bio, persistent_memory_page(address),
1480 block_size, persistent_memory_page_offset(address)) != 0;
1481 }
1482
1483 struct writeback_list {
1484 struct list_head list;
1485 size_t size;
1486 };
1487
1488 static void __writeback_throttle(struct dm_writecache *wc, struct writeback_list *wbl)
1489 {
1490 if (unlikely(wc->max_writeback_jobs)) {
1491 if (READ_ONCE(wc->writeback_size) - wbl->size >= wc->max_writeback_jobs) {
1492 wc_lock(wc);
1493 while (wc->writeback_size - wbl->size >= wc->max_writeback_jobs)
1494 writecache_wait_on_freelist(wc);
1495 wc_unlock(wc);
1496 }
1497 }
1498 cond_resched();
1499 }
1500
1501 static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeback_list *wbl)
1502 {
1503 struct wc_entry *e, *f;
1504 struct bio *bio;
1505 struct writeback_struct *wb;
1506 unsigned max_pages;
1507
1508 while (wbl->size) {
1509 wbl->size--;
1510 e = container_of(wbl->list.prev, struct wc_entry, lru);
1511 list_del(&e->lru);
1512
1513 max_pages = e->wc_list_contiguous;
1514
1515 bio = bio_alloc_bioset(GFP_NOIO, max_pages, &wc->bio_set);
1516 wb = container_of(bio, struct writeback_struct, bio);
1517 wb->wc = wc;
1518 bio->bi_end_io = writecache_writeback_endio;
1519 bio_set_dev(bio, wc->dev->bdev);
1520 bio->bi_iter.bi_sector = read_original_sector(wc, e);
1521 if (max_pages <= WB_LIST_INLINE ||
1522 unlikely(!(wb->wc_list = kmalloc_array(max_pages, sizeof(struct wc_entry *),
1523 GFP_NOIO | __GFP_NORETRY |
1524 __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
1525 wb->wc_list = wb->wc_list_inline;
1526 max_pages = WB_LIST_INLINE;
1527 }
1528
1529 BUG_ON(!wc_add_block(wb, e, GFP_NOIO));
1530
1531 wb->wc_list[0] = e;
1532 wb->wc_list_n = 1;
1533
1534 while (wbl->size && wb->wc_list_n < max_pages) {
1535 f = container_of(wbl->list.prev, struct wc_entry, lru);
1536 if (read_original_sector(wc, f) !=
1537 read_original_sector(wc, e) + (wc->block_size >> SECTOR_SHIFT))
1538 break;
1539 if (!wc_add_block(wb, f, GFP_NOWAIT | __GFP_NOWARN))
1540 break;
1541 wbl->size--;
1542 list_del(&f->lru);
1543 wb->wc_list[wb->wc_list_n++] = f;
1544 e = f;
1545 }
1546 bio_set_op_attrs(bio, REQ_OP_WRITE, WC_MODE_FUA(wc) * REQ_FUA);
1547 if (writecache_has_error(wc)) {
1548 bio->bi_status = BLK_STS_IOERR;
1549 bio_endio(bio);
1550 } else {
1551 submit_bio(bio);
1552 }
1553
1554 __writeback_throttle(wc, wbl);
1555 }
1556 }
1557
1558 static void __writecache_writeback_ssd(struct dm_writecache *wc, struct writeback_list *wbl)
1559 {
1560 struct wc_entry *e, *f;
1561 struct dm_io_region from, to;
1562 struct copy_struct *c;
1563
1564 while (wbl->size) {
1565 unsigned n_sectors;
1566
1567 wbl->size--;
1568 e = container_of(wbl->list.prev, struct wc_entry, lru);
1569 list_del(&e->lru);
1570
1571 n_sectors = e->wc_list_contiguous << (wc->block_size_bits - SECTOR_SHIFT);
1572
1573 from.bdev = wc->ssd_dev->bdev;
1574 from.sector = cache_sector(wc, e);
1575 from.count = n_sectors;
1576 to.bdev = wc->dev->bdev;
1577 to.sector = read_original_sector(wc, e);
1578 to.count = n_sectors;
1579
1580 c = mempool_alloc(&wc->copy_pool, GFP_NOIO);
1581 c->wc = wc;
1582 c->e = e;
1583 c->n_entries = e->wc_list_contiguous;
1584
1585 while ((n_sectors -= wc->block_size >> SECTOR_SHIFT)) {
1586 wbl->size--;
1587 f = container_of(wbl->list.prev, struct wc_entry, lru);
1588 BUG_ON(f != e + 1);
1589 list_del(&f->lru);
1590 e = f;
1591 }
1592
1593 dm_kcopyd_copy(wc->dm_kcopyd, &from, 1, &to, 0, writecache_copy_endio, c);
1594
1595 __writeback_throttle(wc, wbl);
1596 }
1597 }
1598
1599 static void writecache_writeback(struct work_struct *work)
1600 {
1601 struct dm_writecache *wc = container_of(work, struct dm_writecache, writeback_work);
1602 struct blk_plug plug;
1603 struct wc_entry *f, *g, *e = NULL;
1604 struct rb_node *node, *next_node;
1605 struct list_head skipped;
1606 struct writeback_list wbl;
1607 unsigned long n_walked;
1608
1609 wc_lock(wc);
1610 restart:
1611 if (writecache_has_error(wc)) {
1612 wc_unlock(wc);
1613 return;
1614 }
1615
1616 if (unlikely(wc->writeback_all)) {
1617 if (writecache_wait_for_writeback(wc))
1618 goto restart;
1619 }
1620
1621 if (wc->overwrote_committed) {
1622 writecache_wait_for_ios(wc, WRITE);
1623 }
1624
1625 n_walked = 0;
1626 INIT_LIST_HEAD(&skipped);
1627 INIT_LIST_HEAD(&wbl.list);
1628 wbl.size = 0;
1629 while (!list_empty(&wc->lru) &&
1630 (wc->writeback_all ||
1631 wc->freelist_size + wc->writeback_size <= wc->freelist_low_watermark)) {
1632
1633 n_walked++;
1634 if (unlikely(n_walked > WRITEBACK_LATENCY) &&
1635 likely(!wc->writeback_all) && likely(!dm_suspended(wc->ti))) {
1636 queue_work(wc->writeback_wq, &wc->writeback_work);
1637 break;
1638 }
1639
1640 if (unlikely(wc->writeback_all)) {
1641 if (unlikely(!e)) {
1642 writecache_flush(wc);
1643 e = container_of(rb_first(&wc->tree), struct wc_entry, rb_node);
1644 } else
1645 e = g;
1646 } else
1647 e = container_of(wc->lru.prev, struct wc_entry, lru);
1648 BUG_ON(e->write_in_progress);
1649 if (unlikely(!writecache_entry_is_committed(wc, e))) {
1650 writecache_flush(wc);
1651 }
1652 node = rb_prev(&e->rb_node);
1653 if (node) {
1654 f = container_of(node, struct wc_entry, rb_node);
1655 if (unlikely(read_original_sector(wc, f) ==
1656 read_original_sector(wc, e))) {
1657 BUG_ON(!f->write_in_progress);
1658 list_del(&e->lru);
1659 list_add(&e->lru, &skipped);
1660 cond_resched();
1661 continue;
1662 }
1663 }
1664 wc->writeback_size++;
1665 list_del(&e->lru);
1666 list_add(&e->lru, &wbl.list);
1667 wbl.size++;
1668 e->write_in_progress = true;
1669 e->wc_list_contiguous = 1;
1670
1671 f = e;
1672
1673 while (1) {
1674 next_node = rb_next(&f->rb_node);
1675 if (unlikely(!next_node))
1676 break;
1677 g = container_of(next_node, struct wc_entry, rb_node);
1678 if (unlikely(read_original_sector(wc, g) ==
1679 read_original_sector(wc, f))) {
1680 f = g;
1681 continue;
1682 }
1683 if (read_original_sector(wc, g) !=
1684 read_original_sector(wc, f) + (wc->block_size >> SECTOR_SHIFT))
1685 break;
1686 if (unlikely(g->write_in_progress))
1687 break;
1688 if (unlikely(!writecache_entry_is_committed(wc, g)))
1689 break;
1690
1691 if (!WC_MODE_PMEM(wc)) {
1692 if (g != f + 1)
1693 break;
1694 }
1695
1696 n_walked++;
1697
1698
1699
1700 wc->writeback_size++;
1701 list_del(&g->lru);
1702 list_add(&g->lru, &wbl.list);
1703 wbl.size++;
1704 g->write_in_progress = true;
1705 g->wc_list_contiguous = BIO_MAX_PAGES;
1706 f = g;
1707 e->wc_list_contiguous++;
1708 if (unlikely(e->wc_list_contiguous == BIO_MAX_PAGES)) {
1709 if (unlikely(wc->writeback_all)) {
1710 next_node = rb_next(&f->rb_node);
1711 if (likely(next_node))
1712 g = container_of(next_node, struct wc_entry, rb_node);
1713 }
1714 break;
1715 }
1716 }
1717 cond_resched();
1718 }
1719
1720 if (!list_empty(&skipped)) {
1721 list_splice_tail(&skipped, &wc->lru);
1722
1723
1724
1725
1726 if (unlikely(!wbl.size))
1727 writecache_wait_for_writeback(wc);
1728 }
1729
1730 wc_unlock(wc);
1731
1732 blk_start_plug(&plug);
1733
1734 if (WC_MODE_PMEM(wc))
1735 __writecache_writeback_pmem(wc, &wbl);
1736 else
1737 __writecache_writeback_ssd(wc, &wbl);
1738
1739 blk_finish_plug(&plug);
1740
1741 if (unlikely(wc->writeback_all)) {
1742 wc_lock(wc);
1743 while (writecache_wait_for_writeback(wc));
1744 wc_unlock(wc);
1745 }
1746 }
1747
1748 static int calculate_memory_size(uint64_t device_size, unsigned block_size,
1749 size_t *n_blocks_p, size_t *n_metadata_blocks_p)
1750 {
1751 uint64_t n_blocks, offset;
1752 struct wc_entry e;
1753
1754 n_blocks = device_size;
1755 do_div(n_blocks, block_size + sizeof(struct wc_memory_entry));
1756
1757 while (1) {
1758 if (!n_blocks)
1759 return -ENOSPC;
1760
1761 if (n_blocks >= ((size_t)-sizeof(struct wc_memory_superblock) /
1762 sizeof(struct wc_memory_entry)))
1763 return -EFBIG;
1764 offset = offsetof(struct wc_memory_superblock, entries[n_blocks]);
1765 offset = (offset + block_size - 1) & ~(uint64_t)(block_size - 1);
1766 if (offset + n_blocks * block_size <= device_size)
1767 break;
1768 n_blocks--;
1769 }
1770
1771
1772 e.index = n_blocks;
1773 if (e.index != n_blocks)
1774 return -EFBIG;
1775
1776 if (n_blocks_p)
1777 *n_blocks_p = n_blocks;
1778 if (n_metadata_blocks_p)
1779 *n_metadata_blocks_p = offset >> __ffs(block_size);
1780 return 0;
1781 }
1782
1783 static int init_memory(struct dm_writecache *wc)
1784 {
1785 size_t b;
1786 int r;
1787
1788 r = calculate_memory_size(wc->memory_map_size, wc->block_size, &wc->n_blocks, NULL);
1789 if (r)
1790 return r;
1791
1792 r = writecache_alloc_entries(wc);
1793 if (r)
1794 return r;
1795
1796 for (b = 0; b < ARRAY_SIZE(sb(wc)->padding); b++)
1797 pmem_assign(sb(wc)->padding[b], cpu_to_le64(0));
1798 pmem_assign(sb(wc)->version, cpu_to_le32(MEMORY_SUPERBLOCK_VERSION));
1799 pmem_assign(sb(wc)->block_size, cpu_to_le32(wc->block_size));
1800 pmem_assign(sb(wc)->n_blocks, cpu_to_le64(wc->n_blocks));
1801 pmem_assign(sb(wc)->seq_count, cpu_to_le64(0));
1802
1803 for (b = 0; b < wc->n_blocks; b++) {
1804 write_original_sector_seq_count(wc, &wc->entries[b], -1, -1);
1805 cond_resched();
1806 }
1807
1808 writecache_flush_all_metadata(wc);
1809 writecache_commit_flushed(wc, false);
1810 pmem_assign(sb(wc)->magic, cpu_to_le32(MEMORY_SUPERBLOCK_MAGIC));
1811 writecache_flush_region(wc, &sb(wc)->magic, sizeof sb(wc)->magic);
1812 writecache_commit_flushed(wc, false);
1813
1814 return 0;
1815 }
1816
1817 static void writecache_dtr(struct dm_target *ti)
1818 {
1819 struct dm_writecache *wc = ti->private;
1820
1821 if (!wc)
1822 return;
1823
1824 if (wc->endio_thread)
1825 kthread_stop(wc->endio_thread);
1826
1827 if (wc->flush_thread)
1828 kthread_stop(wc->flush_thread);
1829
1830 bioset_exit(&wc->bio_set);
1831
1832 mempool_exit(&wc->copy_pool);
1833
1834 if (wc->writeback_wq)
1835 destroy_workqueue(wc->writeback_wq);
1836
1837 if (wc->dev)
1838 dm_put_device(ti, wc->dev);
1839
1840 if (wc->ssd_dev)
1841 dm_put_device(ti, wc->ssd_dev);
1842
1843 if (wc->entries)
1844 vfree(wc->entries);
1845
1846 if (wc->memory_map) {
1847 if (WC_MODE_PMEM(wc))
1848 persistent_memory_release(wc);
1849 else
1850 vfree(wc->memory_map);
1851 }
1852
1853 if (wc->dm_kcopyd)
1854 dm_kcopyd_client_destroy(wc->dm_kcopyd);
1855
1856 if (wc->dm_io)
1857 dm_io_client_destroy(wc->dm_io);
1858
1859 if (wc->dirty_bitmap)
1860 vfree(wc->dirty_bitmap);
1861
1862 kfree(wc);
1863 }
1864
1865 static int writecache_ctr(struct dm_target *ti, unsigned argc, char **argv)
1866 {
1867 struct dm_writecache *wc;
1868 struct dm_arg_set as;
1869 const char *string;
1870 unsigned opt_params;
1871 size_t offset, data_size;
1872 int i, r;
1873 char dummy;
1874 int high_wm_percent = HIGH_WATERMARK;
1875 int low_wm_percent = LOW_WATERMARK;
1876 uint64_t x;
1877 struct wc_memory_superblock s;
1878
1879 static struct dm_arg _args[] = {
1880 {0, 10, "Invalid number of feature args"},
1881 };
1882
1883 as.argc = argc;
1884 as.argv = argv;
1885
1886 wc = kzalloc(sizeof(struct dm_writecache), GFP_KERNEL);
1887 if (!wc) {
1888 ti->error = "Cannot allocate writecache structure";
1889 r = -ENOMEM;
1890 goto bad;
1891 }
1892 ti->private = wc;
1893 wc->ti = ti;
1894
1895 mutex_init(&wc->lock);
1896 writecache_poison_lists(wc);
1897 init_waitqueue_head(&wc->freelist_wait);
1898 timer_setup(&wc->autocommit_timer, writecache_autocommit_timer, 0);
1899
1900 for (i = 0; i < 2; i++) {
1901 atomic_set(&wc->bio_in_progress[i], 0);
1902 init_waitqueue_head(&wc->bio_in_progress_wait[i]);
1903 }
1904
1905 wc->dm_io = dm_io_client_create();
1906 if (IS_ERR(wc->dm_io)) {
1907 r = PTR_ERR(wc->dm_io);
1908 ti->error = "Unable to allocate dm-io client";
1909 wc->dm_io = NULL;
1910 goto bad;
1911 }
1912
1913 wc->writeback_wq = alloc_workqueue("writecache-writeback", WQ_MEM_RECLAIM, 1);
1914 if (!wc->writeback_wq) {
1915 r = -ENOMEM;
1916 ti->error = "Could not allocate writeback workqueue";
1917 goto bad;
1918 }
1919 INIT_WORK(&wc->writeback_work, writecache_writeback);
1920 INIT_WORK(&wc->flush_work, writecache_flush_work);
1921
1922 raw_spin_lock_init(&wc->endio_list_lock);
1923 INIT_LIST_HEAD(&wc->endio_list);
1924 wc->endio_thread = kthread_create(writecache_endio_thread, wc, "writecache_endio");
1925 if (IS_ERR(wc->endio_thread)) {
1926 r = PTR_ERR(wc->endio_thread);
1927 wc->endio_thread = NULL;
1928 ti->error = "Couldn't spawn endio thread";
1929 goto bad;
1930 }
1931 wake_up_process(wc->endio_thread);
1932
1933
1934
1935
1936 string = dm_shift_arg(&as);
1937 if (!string)
1938 goto bad_arguments;
1939
1940 if (!strcasecmp(string, "s")) {
1941 wc->pmem_mode = false;
1942 } else if (!strcasecmp(string, "p")) {
1943 #ifdef DM_WRITECACHE_HAS_PMEM
1944 wc->pmem_mode = true;
1945 wc->writeback_fua = true;
1946 #else
1947
1948
1949
1950
1951
1952 r = -EOPNOTSUPP;
1953 ti->error = "Persistent memory or DAX not supported on this system";
1954 goto bad;
1955 #endif
1956 } else {
1957 goto bad_arguments;
1958 }
1959
1960 if (WC_MODE_PMEM(wc)) {
1961 r = bioset_init(&wc->bio_set, BIO_POOL_SIZE,
1962 offsetof(struct writeback_struct, bio),
1963 BIOSET_NEED_BVECS);
1964 if (r) {
1965 ti->error = "Could not allocate bio set";
1966 goto bad;
1967 }
1968 } else {
1969 r = mempool_init_kmalloc_pool(&wc->copy_pool, 1, sizeof(struct copy_struct));
1970 if (r) {
1971 ti->error = "Could not allocate mempool";
1972 goto bad;
1973 }
1974 }
1975
1976
1977
1978
1979 string = dm_shift_arg(&as);
1980 if (!string)
1981 goto bad_arguments;
1982 r = dm_get_device(ti, string, dm_table_get_mode(ti->table), &wc->dev);
1983 if (r) {
1984 ti->error = "Origin data device lookup failed";
1985 goto bad;
1986 }
1987
1988
1989
1990
1991 string = dm_shift_arg(&as);
1992 if (!string)
1993 goto bad_arguments;
1994
1995 r = dm_get_device(ti, string, dm_table_get_mode(ti->table), &wc->ssd_dev);
1996 if (r) {
1997 ti->error = "Cache data device lookup failed";
1998 goto bad;
1999 }
2000 wc->memory_map_size = i_size_read(wc->ssd_dev->bdev->bd_inode);
2001
2002
2003
2004
2005 string = dm_shift_arg(&as);
2006 if (!string)
2007 goto bad_arguments;
2008 if (sscanf(string, "%u%c", &wc->block_size, &dummy) != 1 ||
2009 wc->block_size < 512 || wc->block_size > PAGE_SIZE ||
2010 (wc->block_size & (wc->block_size - 1))) {
2011 r = -EINVAL;
2012 ti->error = "Invalid block size";
2013 goto bad;
2014 }
2015 if (wc->block_size < bdev_logical_block_size(wc->dev->bdev) ||
2016 wc->block_size < bdev_logical_block_size(wc->ssd_dev->bdev)) {
2017 r = -EINVAL;
2018 ti->error = "Block size is smaller than device logical block size";
2019 goto bad;
2020 }
2021 wc->block_size_bits = __ffs(wc->block_size);
2022
2023 wc->max_writeback_jobs = MAX_WRITEBACK_JOBS;
2024 wc->autocommit_blocks = !WC_MODE_PMEM(wc) ? AUTOCOMMIT_BLOCKS_SSD : AUTOCOMMIT_BLOCKS_PMEM;
2025 wc->autocommit_jiffies = msecs_to_jiffies(AUTOCOMMIT_MSEC);
2026
2027
2028
2029
2030 r = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
2031 if (r)
2032 goto bad;
2033
2034 while (opt_params) {
2035 string = dm_shift_arg(&as), opt_params--;
2036 if (!strcasecmp(string, "start_sector") && opt_params >= 1) {
2037 unsigned long long start_sector;
2038 string = dm_shift_arg(&as), opt_params--;
2039 if (sscanf(string, "%llu%c", &start_sector, &dummy) != 1)
2040 goto invalid_optional;
2041 wc->start_sector = start_sector;
2042 if (wc->start_sector != start_sector ||
2043 wc->start_sector >= wc->memory_map_size >> SECTOR_SHIFT)
2044 goto invalid_optional;
2045 } else if (!strcasecmp(string, "high_watermark") && opt_params >= 1) {
2046 string = dm_shift_arg(&as), opt_params--;
2047 if (sscanf(string, "%d%c", &high_wm_percent, &dummy) != 1)
2048 goto invalid_optional;
2049 if (high_wm_percent < 0 || high_wm_percent > 100)
2050 goto invalid_optional;
2051 wc->high_wm_percent_set = true;
2052 } else if (!strcasecmp(string, "low_watermark") && opt_params >= 1) {
2053 string = dm_shift_arg(&as), opt_params--;
2054 if (sscanf(string, "%d%c", &low_wm_percent, &dummy) != 1)
2055 goto invalid_optional;
2056 if (low_wm_percent < 0 || low_wm_percent > 100)
2057 goto invalid_optional;
2058 wc->low_wm_percent_set = true;
2059 } else if (!strcasecmp(string, "writeback_jobs") && opt_params >= 1) {
2060 string = dm_shift_arg(&as), opt_params--;
2061 if (sscanf(string, "%u%c", &wc->max_writeback_jobs, &dummy) != 1)
2062 goto invalid_optional;
2063 wc->max_writeback_jobs_set = true;
2064 } else if (!strcasecmp(string, "autocommit_blocks") && opt_params >= 1) {
2065 string = dm_shift_arg(&as), opt_params--;
2066 if (sscanf(string, "%u%c", &wc->autocommit_blocks, &dummy) != 1)
2067 goto invalid_optional;
2068 wc->autocommit_blocks_set = true;
2069 } else if (!strcasecmp(string, "autocommit_time") && opt_params >= 1) {
2070 unsigned autocommit_msecs;
2071 string = dm_shift_arg(&as), opt_params--;
2072 if (sscanf(string, "%u%c", &autocommit_msecs, &dummy) != 1)
2073 goto invalid_optional;
2074 if (autocommit_msecs > 3600000)
2075 goto invalid_optional;
2076 wc->autocommit_jiffies = msecs_to_jiffies(autocommit_msecs);
2077 wc->autocommit_time_set = true;
2078 } else if (!strcasecmp(string, "fua")) {
2079 if (WC_MODE_PMEM(wc)) {
2080 wc->writeback_fua = true;
2081 wc->writeback_fua_set = true;
2082 } else goto invalid_optional;
2083 } else if (!strcasecmp(string, "nofua")) {
2084 if (WC_MODE_PMEM(wc)) {
2085 wc->writeback_fua = false;
2086 wc->writeback_fua_set = true;
2087 } else goto invalid_optional;
2088 } else {
2089 invalid_optional:
2090 r = -EINVAL;
2091 ti->error = "Invalid optional argument";
2092 goto bad;
2093 }
2094 }
2095
2096 if (high_wm_percent < low_wm_percent) {
2097 r = -EINVAL;
2098 ti->error = "High watermark must be greater than or equal to low watermark";
2099 goto bad;
2100 }
2101
2102 if (WC_MODE_PMEM(wc)) {
2103 r = persistent_memory_claim(wc);
2104 if (r) {
2105 ti->error = "Unable to map persistent memory for cache";
2106 goto bad;
2107 }
2108 } else {
2109 size_t n_blocks, n_metadata_blocks;
2110 uint64_t n_bitmap_bits;
2111
2112 wc->memory_map_size -= (uint64_t)wc->start_sector << SECTOR_SHIFT;
2113
2114 bio_list_init(&wc->flush_list);
2115 wc->flush_thread = kthread_create(writecache_flush_thread, wc, "dm_writecache_flush");
2116 if (IS_ERR(wc->flush_thread)) {
2117 r = PTR_ERR(wc->flush_thread);
2118 wc->flush_thread = NULL;
2119 ti->error = "Couldn't spawn flush thread";
2120 goto bad;
2121 }
2122 wake_up_process(wc->flush_thread);
2123
2124 r = calculate_memory_size(wc->memory_map_size, wc->block_size,
2125 &n_blocks, &n_metadata_blocks);
2126 if (r) {
2127 ti->error = "Invalid device size";
2128 goto bad;
2129 }
2130
2131 n_bitmap_bits = (((uint64_t)n_metadata_blocks << wc->block_size_bits) +
2132 BITMAP_GRANULARITY - 1) / BITMAP_GRANULARITY;
2133
2134 if (n_bitmap_bits > 1U << 31) {
2135 r = -EFBIG;
2136 ti->error = "Invalid device size";
2137 goto bad;
2138 }
2139
2140 wc->memory_map = vmalloc(n_metadata_blocks << wc->block_size_bits);
2141 if (!wc->memory_map) {
2142 r = -ENOMEM;
2143 ti->error = "Unable to allocate memory for metadata";
2144 goto bad;
2145 }
2146
2147 wc->dm_kcopyd = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2148 if (IS_ERR(wc->dm_kcopyd)) {
2149 r = PTR_ERR(wc->dm_kcopyd);
2150 ti->error = "Unable to allocate dm-kcopyd client";
2151 wc->dm_kcopyd = NULL;
2152 goto bad;
2153 }
2154
2155 wc->metadata_sectors = n_metadata_blocks << (wc->block_size_bits - SECTOR_SHIFT);
2156 wc->dirty_bitmap_size = (n_bitmap_bits + BITS_PER_LONG - 1) /
2157 BITS_PER_LONG * sizeof(unsigned long);
2158 wc->dirty_bitmap = vzalloc(wc->dirty_bitmap_size);
2159 if (!wc->dirty_bitmap) {
2160 r = -ENOMEM;
2161 ti->error = "Unable to allocate dirty bitmap";
2162 goto bad;
2163 }
2164
2165 r = writecache_read_metadata(wc, wc->block_size >> SECTOR_SHIFT);
2166 if (r) {
2167 ti->error = "Unable to read first block of metadata";
2168 goto bad;
2169 }
2170 }
2171
2172 r = memcpy_mcsafe(&s, sb(wc), sizeof(struct wc_memory_superblock));
2173 if (r) {
2174 ti->error = "Hardware memory error when reading superblock";
2175 goto bad;
2176 }
2177 if (!le32_to_cpu(s.magic) && !le32_to_cpu(s.version)) {
2178 r = init_memory(wc);
2179 if (r) {
2180 ti->error = "Unable to initialize device";
2181 goto bad;
2182 }
2183 r = memcpy_mcsafe(&s, sb(wc), sizeof(struct wc_memory_superblock));
2184 if (r) {
2185 ti->error = "Hardware memory error when reading superblock";
2186 goto bad;
2187 }
2188 }
2189
2190 if (le32_to_cpu(s.magic) != MEMORY_SUPERBLOCK_MAGIC) {
2191 ti->error = "Invalid magic in the superblock";
2192 r = -EINVAL;
2193 goto bad;
2194 }
2195
2196 if (le32_to_cpu(s.version) != MEMORY_SUPERBLOCK_VERSION) {
2197 ti->error = "Invalid version in the superblock";
2198 r = -EINVAL;
2199 goto bad;
2200 }
2201
2202 if (le32_to_cpu(s.block_size) != wc->block_size) {
2203 ti->error = "Block size does not match superblock";
2204 r = -EINVAL;
2205 goto bad;
2206 }
2207
2208 wc->n_blocks = le64_to_cpu(s.n_blocks);
2209
2210 offset = wc->n_blocks * sizeof(struct wc_memory_entry);
2211 if (offset / sizeof(struct wc_memory_entry) != le64_to_cpu(sb(wc)->n_blocks)) {
2212 overflow:
2213 ti->error = "Overflow in size calculation";
2214 r = -EINVAL;
2215 goto bad;
2216 }
2217 offset += sizeof(struct wc_memory_superblock);
2218 if (offset < sizeof(struct wc_memory_superblock))
2219 goto overflow;
2220 offset = (offset + wc->block_size - 1) & ~(size_t)(wc->block_size - 1);
2221 data_size = wc->n_blocks * (size_t)wc->block_size;
2222 if (!offset || (data_size / wc->block_size != wc->n_blocks) ||
2223 (offset + data_size < offset))
2224 goto overflow;
2225 if (offset + data_size > wc->memory_map_size) {
2226 ti->error = "Memory area is too small";
2227 r = -EINVAL;
2228 goto bad;
2229 }
2230
2231 wc->metadata_sectors = offset >> SECTOR_SHIFT;
2232 wc->block_start = (char *)sb(wc) + offset;
2233
2234 x = (uint64_t)wc->n_blocks * (100 - high_wm_percent);
2235 x += 50;
2236 do_div(x, 100);
2237 wc->freelist_high_watermark = x;
2238 x = (uint64_t)wc->n_blocks * (100 - low_wm_percent);
2239 x += 50;
2240 do_div(x, 100);
2241 wc->freelist_low_watermark = x;
2242
2243 r = writecache_alloc_entries(wc);
2244 if (r) {
2245 ti->error = "Cannot allocate memory";
2246 goto bad;
2247 }
2248
2249 ti->num_flush_bios = 1;
2250 ti->flush_supported = true;
2251 ti->num_discard_bios = 1;
2252
2253 if (WC_MODE_PMEM(wc))
2254 persistent_memory_flush_cache(wc->memory_map, wc->memory_map_size);
2255
2256 return 0;
2257
2258 bad_arguments:
2259 r = -EINVAL;
2260 ti->error = "Bad arguments";
2261 bad:
2262 writecache_dtr(ti);
2263 return r;
2264 }
2265
2266 static void writecache_status(struct dm_target *ti, status_type_t type,
2267 unsigned status_flags, char *result, unsigned maxlen)
2268 {
2269 struct dm_writecache *wc = ti->private;
2270 unsigned extra_args;
2271 unsigned sz = 0;
2272 uint64_t x;
2273
2274 switch (type) {
2275 case STATUSTYPE_INFO:
2276 DMEMIT("%ld %llu %llu %llu", writecache_has_error(wc),
2277 (unsigned long long)wc->n_blocks, (unsigned long long)wc->freelist_size,
2278 (unsigned long long)wc->writeback_size);
2279 break;
2280 case STATUSTYPE_TABLE:
2281 DMEMIT("%c %s %s %u ", WC_MODE_PMEM(wc) ? 'p' : 's',
2282 wc->dev->name, wc->ssd_dev->name, wc->block_size);
2283 extra_args = 0;
2284 if (wc->start_sector)
2285 extra_args += 2;
2286 if (wc->high_wm_percent_set)
2287 extra_args += 2;
2288 if (wc->low_wm_percent_set)
2289 extra_args += 2;
2290 if (wc->max_writeback_jobs_set)
2291 extra_args += 2;
2292 if (wc->autocommit_blocks_set)
2293 extra_args += 2;
2294 if (wc->autocommit_time_set)
2295 extra_args += 2;
2296 if (wc->writeback_fua_set)
2297 extra_args++;
2298
2299 DMEMIT("%u", extra_args);
2300 if (wc->start_sector)
2301 DMEMIT(" start_sector %llu", (unsigned long long)wc->start_sector);
2302 if (wc->high_wm_percent_set) {
2303 x = (uint64_t)wc->freelist_high_watermark * 100;
2304 x += wc->n_blocks / 2;
2305 do_div(x, (size_t)wc->n_blocks);
2306 DMEMIT(" high_watermark %u", 100 - (unsigned)x);
2307 }
2308 if (wc->low_wm_percent_set) {
2309 x = (uint64_t)wc->freelist_low_watermark * 100;
2310 x += wc->n_blocks / 2;
2311 do_div(x, (size_t)wc->n_blocks);
2312 DMEMIT(" low_watermark %u", 100 - (unsigned)x);
2313 }
2314 if (wc->max_writeback_jobs_set)
2315 DMEMIT(" writeback_jobs %u", wc->max_writeback_jobs);
2316 if (wc->autocommit_blocks_set)
2317 DMEMIT(" autocommit_blocks %u", wc->autocommit_blocks);
2318 if (wc->autocommit_time_set)
2319 DMEMIT(" autocommit_time %u", jiffies_to_msecs(wc->autocommit_jiffies));
2320 if (wc->writeback_fua_set)
2321 DMEMIT(" %sfua", wc->writeback_fua ? "" : "no");
2322 break;
2323 }
2324 }
2325
2326 static struct target_type writecache_target = {
2327 .name = "writecache",
2328 .version = {1, 1, 1},
2329 .module = THIS_MODULE,
2330 .ctr = writecache_ctr,
2331 .dtr = writecache_dtr,
2332 .status = writecache_status,
2333 .postsuspend = writecache_suspend,
2334 .resume = writecache_resume,
2335 .message = writecache_message,
2336 .map = writecache_map,
2337 .end_io = writecache_end_io,
2338 .iterate_devices = writecache_iterate_devices,
2339 .io_hints = writecache_io_hints,
2340 };
2341
2342 static int __init dm_writecache_init(void)
2343 {
2344 int r;
2345
2346 r = dm_register_target(&writecache_target);
2347 if (r < 0) {
2348 DMERR("register failed %d", r);
2349 return r;
2350 }
2351
2352 return 0;
2353 }
2354
2355 static void __exit dm_writecache_exit(void)
2356 {
2357 dm_unregister_target(&writecache_target);
2358 }
2359
2360 module_init(dm_writecache_init);
2361 module_exit(dm_writecache_exit);
2362
2363 MODULE_DESCRIPTION(DM_NAME " writecache target");
2364 MODULE_AUTHOR("Mikulas Patocka <dm-devel@redhat.com>");
2365 MODULE_LICENSE("GPL");