1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2018 Red Hat. All rights reserved.
4 *
5 * This file is released under the GPL.
6 */
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) \
42do { \
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
57struct wc_memory_entry {
58 __le64 original_sector;
59 __le64 seq_count;
60};
61
62struct 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
77struct 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
106struct 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
188struct 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 unsigned page_offset;
194 struct page *page;
195 struct wc_entry *wc_list_inline[WB_LIST_INLINE];
196 struct bio bio;
197};
198
199struct copy_struct {
200 struct list_head endio_entry;
201 struct dm_writecache *wc;
202 struct wc_entry *e;
203 unsigned n_entries;
204 int error;
205};
206
207DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(dm_writecache_throttle,
208 "A percentage of time allocated for data copying");
209
210static void wc_lock(struct dm_writecache *wc)
211{
212 mutex_lock(&wc->lock);
213}
214
215static void wc_unlock(struct dm_writecache *wc)
216{
217 mutex_unlock(&wc->lock);
218}
219
220#ifdef DM_WRITECACHE_HAS_PMEM
221static int persistent_memory_claim(struct dm_writecache *wc)
222{
223 int r;
224 loff_t s;
225 long p, da;
226 pfn_t pfn;
227 int id;
228 struct page **pages;
229
230 wc->memory_vmapped = false;
231
232 if (!wc->ssd_dev->dax_dev) {
233 r = -EOPNOTSUPP;
234 goto err1;
235 }
236 s = wc->memory_map_size;
237 p = s >> PAGE_SHIFT;
238 if (!p) {
239 r = -EINVAL;
240 goto err1;
241 }
242 if (p != s >> PAGE_SHIFT) {
243 r = -EOVERFLOW;
244 goto err1;
245 }
246
247 id = dax_read_lock();
248
249 da = dax_direct_access(wc->ssd_dev->dax_dev, 0, p, &wc->memory_map, &pfn);
250 if (da < 0) {
251 wc->memory_map = NULL;
252 r = da;
253 goto err2;
254 }
255 if (!pfn_t_has_page(pfn)) {
256 wc->memory_map = NULL;
257 r = -EOPNOTSUPP;
258 goto err2;
259 }
260 if (da != p) {
261 long i;
262 wc->memory_map = NULL;
263 pages = kvmalloc_array(p, sizeof(struct page *), GFP_KERNEL);
264 if (!pages) {
265 r = -ENOMEM;
266 goto err2;
267 }
268 i = 0;
269 do {
270 long daa;
271 daa = dax_direct_access(wc->ssd_dev->dax_dev, i, p - i,
272 NULL, &pfn);
273 if (daa <= 0) {
274 r = daa ? daa : -EINVAL;
275 goto err3;
276 }
277 if (!pfn_t_has_page(pfn)) {
278 r = -EOPNOTSUPP;
279 goto err3;
280 }
281 while (daa-- && i < p) {
282 pages[i++] = pfn_t_to_page(pfn);
283 pfn.val++;
284 }
285 } while (i < p);
286 wc->memory_map = vmap(pages, p, VM_MAP, PAGE_KERNEL);
287 if (!wc->memory_map) {
288 r = -ENOMEM;
289 goto err3;
290 }
291 kvfree(pages);
292 wc->memory_vmapped = true;
293 }
294
295 dax_read_unlock(id);
296
297 wc->memory_map += (size_t)wc->start_sector << SECTOR_SHIFT;
298 wc->memory_map_size -= (size_t)wc->start_sector << SECTOR_SHIFT;
299
300 return 0;
301err3:
302 kvfree(pages);
303err2:
304 dax_read_unlock(id);
305err1:
306 return r;
307}
308#else
309static int persistent_memory_claim(struct dm_writecache *wc)
310{
311 BUG();
312}
313#endif
314
315static void persistent_memory_release(struct dm_writecache *wc)
316{
317 if (wc->memory_vmapped)
318 vunmap(wc->memory_map - ((size_t)wc->start_sector << SECTOR_SHIFT));
319}
320
321static struct page *persistent_memory_page(void *addr)
322{
323 if (is_vmalloc_addr(addr))
324 return vmalloc_to_page(addr);
325 else
326 return virt_to_page(addr);
327}
328
329static unsigned persistent_memory_page_offset(void *addr)
330{
331 return (unsigned long)addr & (PAGE_SIZE - 1);
332}
333
334static void persistent_memory_flush_cache(void *ptr, size_t size)
335{
336 if (is_vmalloc_addr(ptr))
337 flush_kernel_vmap_range(ptr, size);
338}
339
340static void persistent_memory_invalidate_cache(void *ptr, size_t size)
341{
342 if (is_vmalloc_addr(ptr))
343 invalidate_kernel_vmap_range(ptr, size);
344}
345
346static struct wc_memory_superblock *sb(struct dm_writecache *wc)
347{
348 return wc->memory_map;
349}
350
351static struct wc_memory_entry *memory_entry(struct dm_writecache *wc, struct wc_entry *e)
352{
353 return &sb(wc)->entries[e->index];
354}
355
356static void *memory_data(struct dm_writecache *wc, struct wc_entry *e)
357{
358 return (char *)wc->block_start + (e->index << wc->block_size_bits);
359}
360
361static sector_t cache_sector(struct dm_writecache *wc, struct wc_entry *e)
362{
363 return wc->start_sector + wc->metadata_sectors +
364 ((sector_t)e->index << (wc->block_size_bits - SECTOR_SHIFT));
365}
366
367static uint64_t read_original_sector(struct dm_writecache *wc, struct wc_entry *e)
368{
369#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
370 return e->original_sector;
371#else
372 return le64_to_cpu(memory_entry(wc, e)->original_sector);
373#endif
374}
375
376static uint64_t read_seq_count(struct dm_writecache *wc, struct wc_entry *e)
377{
378#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
379 return e->seq_count;
380#else
381 return le64_to_cpu(memory_entry(wc, e)->seq_count);
382#endif
383}
384
385static void clear_seq_count(struct dm_writecache *wc, struct wc_entry *e)
386{
387#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
388 e->seq_count = -1;
389#endif
390 pmem_assign(memory_entry(wc, e)->seq_count, cpu_to_le64(-1));
391}
392
393static void write_original_sector_seq_count(struct dm_writecache *wc, struct wc_entry *e,
394 uint64_t original_sector, uint64_t seq_count)
395{
396 struct wc_memory_entry me;
397#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
398 e->original_sector = original_sector;
399 e->seq_count = seq_count;
400#endif
401 me.original_sector = cpu_to_le64(original_sector);
402 me.seq_count = cpu_to_le64(seq_count);
403 pmem_assign(*memory_entry(wc, e), me);
404}
405
406#define writecache_error(wc, err, msg, arg...) \
407do { \
408 if (!cmpxchg(&(wc)->error, 0, err)) \
409 DMERR(msg, ##arg); \
410 wake_up(&(wc)->freelist_wait); \
411} while (0)
412
413#define writecache_has_error(wc) (unlikely(READ_ONCE((wc)->error)))
414
415static void writecache_flush_all_metadata(struct dm_writecache *wc)
416{
417 if (!WC_MODE_PMEM(wc))
418 memset(wc->dirty_bitmap, -1, wc->dirty_bitmap_size);
419}
420
421static void writecache_flush_region(struct dm_writecache *wc, void *ptr, size_t size)
422{
423 if (!WC_MODE_PMEM(wc))
424 __set_bit(((char *)ptr - (char *)wc->memory_map) / BITMAP_GRANULARITY,
425 wc->dirty_bitmap);
426}
427
428static void writecache_disk_flush(struct dm_writecache *wc, struct dm_dev *dev);
429
430struct io_notify {
431 struct dm_writecache *wc;
432 struct completion c;
433 atomic_t count;
434};
435
436static void writecache_notify_io(unsigned long error, void *context)
437{
438 struct io_notify *endio = context;
439
440 if (unlikely(error != 0))
441 writecache_error(endio->wc, -EIO, "error writing metadata");
442 BUG_ON(atomic_read(&endio->count) <= 0);
443 if (atomic_dec_and_test(&endio->count))
444 complete(&endio->c);
445}
446
447static void ssd_commit_flushed(struct dm_writecache *wc)
448{
449 struct dm_io_region region;
450 struct dm_io_request req;
451 struct io_notify endio = {
452 wc,
453 COMPLETION_INITIALIZER_ONSTACK(endio.c),
454 ATOMIC_INIT(1),
455 };
456 unsigned bitmap_bits = wc->dirty_bitmap_size * 8;
457 unsigned i = 0;
458
459 while (1) {
460 unsigned j;
461 i = find_next_bit(wc->dirty_bitmap, bitmap_bits, i);
462 if (unlikely(i == bitmap_bits))
463 break;
464 j = find_next_zero_bit(wc->dirty_bitmap, bitmap_bits, i);
465
466 region.bdev = wc->ssd_dev->bdev;
467 region.sector = (sector_t)i * (BITMAP_GRANULARITY >> SECTOR_SHIFT);
468 region.count = (sector_t)(j - i) * (BITMAP_GRANULARITY >> SECTOR_SHIFT);
469
470 if (unlikely(region.sector >= wc->metadata_sectors))
471 break;
472 if (unlikely(region.sector + region.count > wc->metadata_sectors))
473 region.count = wc->metadata_sectors - region.sector;
474
475 region.sector += wc->start_sector;
476 atomic_inc(&endio.count);
477 req.bi_op = REQ_OP_WRITE;
478 req.bi_op_flags = REQ_SYNC;
479 req.mem.type = DM_IO_VMA;
480 req.mem.ptr.vma = (char *)wc->memory_map + (size_t)i * BITMAP_GRANULARITY;
481 req.client = wc->dm_io;
482 req.notify.fn = writecache_notify_io;
483 req.notify.context = &endio;
484
485 /* writing via async dm-io (implied by notify.fn above) won't return an error */
486 (void) dm_io(&req, 1, &region, NULL);
487 i = j;
488 }
489
490 writecache_notify_io(0, &endio);
491 wait_for_completion_io(&endio.c);
492
493 writecache_disk_flush(wc, wc->ssd_dev);
494
495 memset(wc->dirty_bitmap, 0, wc->dirty_bitmap_size);
496}
497
498static void writecache_commit_flushed(struct dm_writecache *wc)
499{
500 if (WC_MODE_PMEM(wc))
501 wmb();
502 else
503 ssd_commit_flushed(wc);
504}
505
506static void writecache_disk_flush(struct dm_writecache *wc, struct dm_dev *dev)
507{
508 int r;
509 struct dm_io_region region;
510 struct dm_io_request req;
511
512 region.bdev = dev->bdev;
513 region.sector = 0;
514 region.count = 0;
515 req.bi_op = REQ_OP_WRITE;
516 req.bi_op_flags = REQ_PREFLUSH;
517 req.mem.type = DM_IO_KMEM;
518 req.mem.ptr.addr = NULL;
519 req.client = wc->dm_io;
520 req.notify.fn = NULL;
521
522 r = dm_io(&req, 1, &region, NULL);
523 if (unlikely(r))
524 writecache_error(wc, r, "error flushing metadata: %d", r);
525}
526
527static void writecache_wait_for_ios(struct dm_writecache *wc, int direction)
528{
529 wait_event(wc->bio_in_progress_wait[direction],
530 !atomic_read(&wc->bio_in_progress[direction]));
531}
532
533#define WFE_RETURN_FOLLOWING 1
534#define WFE_LOWEST_SEQ 2
535
536static struct wc_entry *writecache_find_entry(struct dm_writecache *wc,
537 uint64_t block, int flags)
538{
539 struct wc_entry *e;
540 struct rb_node *node = wc->tree.rb_node;
541
542 if (unlikely(!node))
543 return NULL;
544
545 while (1) {
546 e = container_of(node, struct wc_entry, rb_node);
547 if (read_original_sector(wc, e) == block)
548 break;
549 node = (read_original_sector(wc, e) >= block ?
550 e->rb_node.rb_left : e->rb_node.rb_right);
551 if (unlikely(!node)) {
552 if (!(flags & WFE_RETURN_FOLLOWING)) {
553 return NULL;
554 }
555 if (read_original_sector(wc, e) >= block) {
556 break;
557 } else {
558 node = rb_next(&e->rb_node);
559 if (unlikely(!node)) {
560 return NULL;
561 }
562 e = container_of(node, struct wc_entry, rb_node);
563 break;
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 (!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
583static 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
601static 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
607static 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
628static struct wc_entry *writecache_pop_from_freelist(struct dm_writecache *wc)
629{
630 struct wc_entry *e;
631
632 if (WC_MODE_SORT_FREELIST(wc)) {
633 struct rb_node *next;
634 if (unlikely(!wc->current_free))
635 return NULL;
636 e = wc->current_free;
637 next = rb_next(&e->rb_node);
638 rb_erase(&e->rb_node, &wc->freetree);
639 if (unlikely(!next))
640 next = rb_first(&wc->freetree);
641 wc->current_free = next ? container_of(next, struct wc_entry, rb_node) : NULL;
642 } else {
643 if (unlikely(list_empty(&wc->freelist)))
644 return NULL;
645 e = container_of(wc->freelist.next, struct wc_entry, lru);
646 list_del(&e->lru);
647 }
648 wc->freelist_size--;
649 if (unlikely(wc->freelist_size + wc->writeback_size <= wc->freelist_high_watermark))
650 queue_work(wc->writeback_wq, &wc->writeback_work);
651
652 return e;
653}
654
655static void writecache_free_entry(struct dm_writecache *wc, struct wc_entry *e)
656{
657 writecache_unlink(wc, e);
658 writecache_add_to_freelist(wc, e);
659 clear_seq_count(wc, e);
660 writecache_flush_region(wc, memory_entry(wc, e), sizeof(struct wc_memory_entry));
661 if (unlikely(waitqueue_active(&wc->freelist_wait)))
662 wake_up(&wc->freelist_wait);
663}
664
665static void writecache_wait_on_freelist(struct dm_writecache *wc)
666{
667 DEFINE_WAIT(wait);
668
669 prepare_to_wait(&wc->freelist_wait, &wait, TASK_UNINTERRUPTIBLE);
670 wc_unlock(wc);
671 io_schedule();
672 finish_wait(&wc->freelist_wait, &wait);
673 wc_lock(wc);
674}
675
676static void writecache_poison_lists(struct dm_writecache *wc)
677{
678 /*
679 * Catch incorrect access to these values while the device is suspended.
680 */
681 memset(&wc->tree, -1, sizeof wc->tree);
682 wc->lru.next = LIST_POISON1;
683 wc->lru.prev = LIST_POISON2;
684 wc->freelist.next = LIST_POISON1;
685 wc->freelist.prev = LIST_POISON2;
686}
687
688static void writecache_flush_entry(struct dm_writecache *wc, struct wc_entry *e)
689{
690 writecache_flush_region(wc, memory_entry(wc, e), sizeof(struct wc_memory_entry));
691 if (WC_MODE_PMEM(wc))
692 writecache_flush_region(wc, memory_data(wc, e), wc->block_size);
693}
694
695static bool writecache_entry_is_committed(struct dm_writecache *wc, struct wc_entry *e)
696{
697 return read_seq_count(wc, e) < wc->seq_count;
698}
699
700static void writecache_flush(struct dm_writecache *wc)
701{
702 struct wc_entry *e, *e2;
703 bool need_flush_after_free;
704
705 wc->uncommitted_blocks = 0;
706 del_timer(&wc->autocommit_timer);
707
708 if (list_empty(&wc->lru))
709 return;
710
711 e = container_of(wc->lru.next, struct wc_entry, lru);
712 if (writecache_entry_is_committed(wc, e)) {
713 if (wc->overwrote_committed) {
714 writecache_wait_for_ios(wc, WRITE);
715 writecache_disk_flush(wc, wc->ssd_dev);
716 wc->overwrote_committed = false;
717 }
718 return;
719 }
720 while (1) {
721 writecache_flush_entry(wc, e);
722 if (unlikely(e->lru.next == &wc->lru))
723 break;
724 e2 = container_of(e->lru.next, struct wc_entry, lru);
725 if (writecache_entry_is_committed(wc, e2))
726 break;
727 e = e2;
728 cond_resched();
729 }
730 writecache_commit_flushed(wc);
731
732 writecache_wait_for_ios(wc, WRITE);
733
734 wc->seq_count++;
735 pmem_assign(sb(wc)->seq_count, cpu_to_le64(wc->seq_count));
736 writecache_flush_region(wc, &sb(wc)->seq_count, sizeof sb(wc)->seq_count);
737 writecache_commit_flushed(wc);
738
739 wc->overwrote_committed = false;
740
741 need_flush_after_free = false;
742 while (1) {
743 /* Free another committed entry with lower seq-count */
744 struct rb_node *rb_node = rb_prev(&e->rb_node);
745
746 if (rb_node) {
747 e2 = container_of(rb_node, struct wc_entry, rb_node);
748 if (read_original_sector(wc, e2) == read_original_sector(wc, e) &&
749 likely(!e2->write_in_progress)) {
750 writecache_free_entry(wc, e2);
751 need_flush_after_free = true;
752 }
753 }
754 if (unlikely(e->lru.prev == &wc->lru))
755 break;
756 e = container_of(e->lru.prev, struct wc_entry, lru);
757 cond_resched();
758 }
759
760 if (need_flush_after_free)
761 writecache_commit_flushed(wc);
762}
763
764static void writecache_flush_work(struct work_struct *work)
765{
766 struct dm_writecache *wc = container_of(work, struct dm_writecache, flush_work);
767
768 wc_lock(wc);
769 writecache_flush(wc);
770 wc_unlock(wc);
771}
772
773static void writecache_autocommit_timer(struct timer_list *t)
774{
775 struct dm_writecache *wc = from_timer(wc, t, autocommit_timer);
776 if (!writecache_has_error(wc))
777 queue_work(wc->writeback_wq, &wc->flush_work);
778}
779
780static void writecache_schedule_autocommit(struct dm_writecache *wc)
781{
782 if (!timer_pending(&wc->autocommit_timer))
783 mod_timer(&wc->autocommit_timer, jiffies + wc->autocommit_jiffies);
784}
785
786static void writecache_discard(struct dm_writecache *wc, sector_t start, sector_t end)
787{
788 struct wc_entry *e;
789 bool discarded_something = false;
790
791 e = writecache_find_entry(wc, start, WFE_RETURN_FOLLOWING | WFE_LOWEST_SEQ);
792 if (unlikely(!e))
793 return;
794
795 while (read_original_sector(wc, e) < end) {
796 struct rb_node *node = rb_next(&e->rb_node);
797
798 if (likely(!e->write_in_progress)) {
799 if (!discarded_something) {
800 writecache_wait_for_ios(wc, READ);
801 writecache_wait_for_ios(wc, WRITE);
802 discarded_something = true;
803 }
804 writecache_free_entry(wc, e);
805 }
806
807 if (!node)
808 break;
809
810 e = container_of(node, struct wc_entry, rb_node);
811 }
812
813 if (discarded_something)
814 writecache_commit_flushed(wc);
815}
816
817static bool writecache_wait_for_writeback(struct dm_writecache *wc)
818{
819 if (wc->writeback_size) {
820 writecache_wait_on_freelist(wc);
821 return true;
822 }
823 return false;
824}
825
826static void writecache_suspend(struct dm_target *ti)
827{
828 struct dm_writecache *wc = ti->private;
829 bool flush_on_suspend;
830
831 del_timer_sync(&wc->autocommit_timer);
832
833 wc_lock(wc);
834 writecache_flush(wc);
835 flush_on_suspend = wc->flush_on_suspend;
836 if (flush_on_suspend) {
837 wc->flush_on_suspend = false;
838 wc->writeback_all++;
839 queue_work(wc->writeback_wq, &wc->writeback_work);
840 }
841 wc_unlock(wc);
842
843 flush_workqueue(wc->writeback_wq);
844
845 wc_lock(wc);
846 if (flush_on_suspend)
847 wc->writeback_all--;
848 while (writecache_wait_for_writeback(wc));
849
850 if (WC_MODE_PMEM(wc))
851 persistent_memory_flush_cache(wc->memory_map, wc->memory_map_size);
852
853 writecache_poison_lists(wc);
854
855 wc_unlock(wc);
856}
857
858static int writecache_alloc_entries(struct dm_writecache *wc)
859{
860 size_t b;
861
862 if (wc->entries)
863 return 0;
864 wc->entries = vmalloc(array_size(sizeof(struct wc_entry), wc->n_blocks));
865 if (!wc->entries)
866 return -ENOMEM;
867 for (b = 0; b < wc->n_blocks; b++) {
868 struct wc_entry *e = &wc->entries[b];
869 e->index = b;
870 e->write_in_progress = false;
871 }
872
873 return 0;
874}
875
876static void writecache_resume(struct dm_target *ti)
877{
878 struct dm_writecache *wc = ti->private;
879 size_t b;
880 bool need_flush = false;
881 __le64 sb_seq_count;
882 int r;
883
884 wc_lock(wc);
885
886 if (WC_MODE_PMEM(wc))
887 persistent_memory_invalidate_cache(wc->memory_map, wc->memory_map_size);
888
889 wc->tree = RB_ROOT;
890 INIT_LIST_HEAD(&wc->lru);
891 if (WC_MODE_SORT_FREELIST(wc)) {
892 wc->freetree = RB_ROOT;
893 wc->current_free = NULL;
894 } else {
895 INIT_LIST_HEAD(&wc->freelist);
896 }
897 wc->freelist_size = 0;
898
899 r = memcpy_mcsafe(&sb_seq_count, &sb(wc)->seq_count, sizeof(uint64_t));
900 if (r) {
901 writecache_error(wc, r, "hardware memory error when reading superblock: %d", r);
902 sb_seq_count = cpu_to_le64(0);
903 }
904 wc->seq_count = le64_to_cpu(sb_seq_count);
905
906#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
907 for (b = 0; b < wc->n_blocks; b++) {
908 struct wc_entry *e = &wc->entries[b];
909 struct wc_memory_entry wme;
910 if (writecache_has_error(wc)) {
911 e->original_sector = -1;
912 e->seq_count = -1;
913 continue;
914 }
915 r = memcpy_mcsafe(&wme, memory_entry(wc, e), sizeof(struct wc_memory_entry));
916 if (r) {
917 writecache_error(wc, r, "hardware memory error when reading metadata entry %lu: %d",
918 (unsigned long)b, r);
919 e->original_sector = -1;
920 e->seq_count = -1;
921 } else {
922 e->original_sector = le64_to_cpu(wme.original_sector);
923 e->seq_count = le64_to_cpu(wme.seq_count);
924 }
925 }
926#endif
927 for (b = 0; b < wc->n_blocks; b++) {
928 struct wc_entry *e = &wc->entries[b];
929 if (!writecache_entry_is_committed(wc, e)) {
930 if (read_seq_count(wc, e) != -1) {
931erase_this:
932 clear_seq_count(wc, e);
933 need_flush = true;
934 }
935 writecache_add_to_freelist(wc, e);
936 } else {
937 struct wc_entry *old;
938
939 old = writecache_find_entry(wc, read_original_sector(wc, e), 0);
940 if (!old) {
941 writecache_insert_entry(wc, e);
942 } else {
943 if (read_seq_count(wc, old) == read_seq_count(wc, e)) {
944 writecache_error(wc, -EINVAL,
945 "two identical entries, position %llu, sector %llu, sequence %llu",
946 (unsigned long long)b, (unsigned long long)read_original_sector(wc, e),
947 (unsigned long long)read_seq_count(wc, e));
948 }
949 if (read_seq_count(wc, old) > read_seq_count(wc, e)) {
950 goto erase_this;
951 } else {
952 writecache_free_entry(wc, old);
953 writecache_insert_entry(wc, e);
954 need_flush = true;
955 }
956 }
957 }
958 cond_resched();
959 }
960
961 if (need_flush) {
962 writecache_flush_all_metadata(wc);
963 writecache_commit_flushed(wc);
964 }
965
966 wc_unlock(wc);
967}
968
969static int process_flush_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
970{
971 if (argc != 1)
972 return -EINVAL;
973
974 wc_lock(wc);
975 if (dm_suspended(wc->ti)) {
976 wc_unlock(wc);
977 return -EBUSY;
978 }
979 if (writecache_has_error(wc)) {
980 wc_unlock(wc);
981 return -EIO;
982 }
983
984 writecache_flush(wc);
985 wc->writeback_all++;
986 queue_work(wc->writeback_wq, &wc->writeback_work);
987 wc_unlock(wc);
988
989 flush_workqueue(wc->writeback_wq);
990
991 wc_lock(wc);
992 wc->writeback_all--;
993 if (writecache_has_error(wc)) {
994 wc_unlock(wc);
995 return -EIO;
996 }
997 wc_unlock(wc);
998
999 return 0;
1000}
1001
1002static int process_flush_on_suspend_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
1003{
1004 if (argc != 1)
1005 return -EINVAL;
1006
1007 wc_lock(wc);
1008 wc->flush_on_suspend = true;
1009 wc_unlock(wc);
1010
1011 return 0;
1012}
1013
1014static int writecache_message(struct dm_target *ti, unsigned argc, char **argv,
1015 char *result, unsigned maxlen)
1016{
1017 int r = -EINVAL;
1018 struct dm_writecache *wc = ti->private;
1019
1020 if (!strcasecmp(argv[0], "flush"))
1021 r = process_flush_mesg(argc, argv, wc);
1022 else if (!strcasecmp(argv[0], "flush_on_suspend"))
1023 r = process_flush_on_suspend_mesg(argc, argv, wc);
1024 else
1025 DMERR("unrecognised message received: %s", argv[0]);
1026
1027 return r;
1028}
1029
1030static void bio_copy_block(struct dm_writecache *wc, struct bio *bio, void *data)
1031{
1032 void *buf;
1033 unsigned long flags;
1034 unsigned size;
1035 int rw = bio_data_dir(bio);
1036 unsigned remaining_size = wc->block_size;
1037
1038 do {
1039 struct bio_vec bv = bio_iter_iovec(bio, bio->bi_iter);
1040 buf = bvec_kmap_irq(&bv, &flags);
1041 size = bv.bv_len;
1042 if (unlikely(size > remaining_size))
1043 size = remaining_size;
1044
1045 if (rw == READ) {
1046 int r;
1047 r = memcpy_mcsafe(buf, data, size);
1048 flush_dcache_page(bio_page(bio));
1049 if (unlikely(r)) {
1050 writecache_error(wc, r, "hardware memory error when reading data: %d", r);
1051 bio->bi_status = BLK_STS_IOERR;
1052 }
1053 } else {
1054 flush_dcache_page(bio_page(bio));
1055 memcpy_flushcache(data, buf, size);
1056 }
1057
1058 bvec_kunmap_irq(buf, &flags);
1059
1060 data = (char *)data + size;
1061 remaining_size -= size;
1062 bio_advance(bio, size);
1063 } while (unlikely(remaining_size));
1064}
1065
1066static int writecache_flush_thread(void *data)
1067{
1068 struct dm_writecache *wc = data;
1069
1070 while (1) {
1071 struct bio *bio;
1072
1073 wc_lock(wc);
1074 bio = bio_list_pop(&wc->flush_list);
1075 if (!bio) {
1076 set_current_state(TASK_INTERRUPTIBLE);
1077 wc_unlock(wc);
1078
1079 if (unlikely(kthread_should_stop())) {
1080 set_current_state(TASK_RUNNING);
1081 break;
1082 }
1083
1084 schedule();
1085 continue;
1086 }
1087
1088 if (bio_op(bio) == REQ_OP_DISCARD) {
1089 writecache_discard(wc, bio->bi_iter.bi_sector,
1090 bio_end_sector(bio));
1091 wc_unlock(wc);
1092 bio_set_dev(bio, wc->dev->bdev);
1093 generic_make_request(bio);
1094 } else {
1095 writecache_flush(wc);
1096 wc_unlock(wc);
1097 if (writecache_has_error(wc))
1098 bio->bi_status = BLK_STS_IOERR;
1099 bio_endio(bio);
1100 }
1101 }
1102
1103 return 0;
1104}
1105
1106static void writecache_offload_bio(struct dm_writecache *wc, struct bio *bio)
1107{
1108 if (bio_list_empty(&wc->flush_list))
1109 wake_up_process(wc->flush_thread);
1110 bio_list_add(&wc->flush_list, bio);
1111}
1112
1113static int writecache_map(struct dm_target *ti, struct bio *bio)
1114{
1115 struct wc_entry *e;
1116 struct dm_writecache *wc = ti->private;
1117
1118 bio->bi_private = NULL;
1119
1120 wc_lock(wc);
1121
1122 if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
1123 if (writecache_has_error(wc))
1124 goto unlock_error;
1125 if (WC_MODE_PMEM(wc)) {
1126 writecache_flush(wc);
1127 if (writecache_has_error(wc))
1128 goto unlock_error;
1129 goto unlock_submit;
1130 } else {
1131 writecache_offload_bio(wc, bio);
1132 goto unlock_return;
1133 }
1134 }
1135
1136 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
1137
1138 if (unlikely((((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) &
1139 (wc->block_size / 512 - 1)) != 0)) {
1140 DMERR("I/O is not aligned, sector %llu, size %u, block size %u",
1141 (unsigned long long)bio->bi_iter.bi_sector,
1142 bio->bi_iter.bi_size, wc->block_size);
1143 goto unlock_error;
1144 }
1145
1146 if (unlikely(bio_op(bio) == REQ_OP_DISCARD)) {
1147 if (writecache_has_error(wc))
1148 goto unlock_error;
1149 if (WC_MODE_PMEM(wc)) {
1150 writecache_discard(wc, bio->bi_iter.bi_sector, bio_end_sector(bio));
1151 goto unlock_remap_origin;
1152 } else {
1153 writecache_offload_bio(wc, bio);
1154 goto unlock_return;
1155 }
1156 }
1157
1158 if (bio_data_dir(bio) == READ) {
1159read_next_block:
1160 e = writecache_find_entry(wc, bio->bi_iter.bi_sector, WFE_RETURN_FOLLOWING);
1161 if (e && read_original_sector(wc, e) == bio->bi_iter.bi_sector) {
1162 if (WC_MODE_PMEM(wc)) {
1163 bio_copy_block(wc, bio, memory_data(wc, e));
1164 if (bio->bi_iter.bi_size)
1165 goto read_next_block;
1166 goto unlock_submit;
1167 } else {
1168 dm_accept_partial_bio(bio, wc->block_size >> SECTOR_SHIFT);
1169 bio_set_dev(bio, wc->ssd_dev->bdev);
1170 bio->bi_iter.bi_sector = cache_sector(wc, e);
1171 if (!writecache_entry_is_committed(wc, e))
1172 writecache_wait_for_ios(wc, WRITE);
1173 goto unlock_remap;
1174 }
1175 } else {
1176 if (e) {
1177 sector_t next_boundary =
1178 read_original_sector(wc, e) - bio->bi_iter.bi_sector;
1179 if (next_boundary < bio->bi_iter.bi_size >> SECTOR_SHIFT) {
1180 dm_accept_partial_bio(bio, next_boundary);
1181 }
1182 }
1183 goto unlock_remap_origin;
1184 }
1185 } else {
1186 do {
1187 if (writecache_has_error(wc))
1188 goto unlock_error;
1189 e = writecache_find_entry(wc, bio->bi_iter.bi_sector, 0);
1190 if (e) {
1191 if (!writecache_entry_is_committed(wc, e))
1192 goto bio_copy;
1193 if (!WC_MODE_PMEM(wc) && !e->write_in_progress) {
1194 wc->overwrote_committed = true;
1195 goto bio_copy;
1196 }
1197 }
1198 e = writecache_pop_from_freelist(wc);
1199 if (unlikely(!e)) {
1200 writecache_wait_on_freelist(wc);
1201 continue;
1202 }
1203 write_original_sector_seq_count(wc, e, bio->bi_iter.bi_sector, wc->seq_count);
1204 writecache_insert_entry(wc, e);
1205 wc->uncommitted_blocks++;
1206bio_copy:
1207 if (WC_MODE_PMEM(wc)) {
1208 bio_copy_block(wc, bio, memory_data(wc, e));
1209 } else {
1210 dm_accept_partial_bio(bio, wc->block_size >> SECTOR_SHIFT);
1211 bio_set_dev(bio, wc->ssd_dev->bdev);
1212 bio->bi_iter.bi_sector = cache_sector(wc, e);
1213 if (unlikely(wc->uncommitted_blocks >= wc->autocommit_blocks)) {
1214 wc->uncommitted_blocks = 0;
1215 queue_work(wc->writeback_wq, &wc->flush_work);
1216 } else {
1217 writecache_schedule_autocommit(wc);
1218 }
1219 goto unlock_remap;
1220 }
1221 } while (bio->bi_iter.bi_size);
1222
1223 if (unlikely(wc->uncommitted_blocks >= wc->autocommit_blocks))
1224 writecache_flush(wc);
1225 else
1226 writecache_schedule_autocommit(wc);
1227 goto unlock_submit;
1228 }
1229
1230unlock_remap_origin:
1231 bio_set_dev(bio, wc->dev->bdev);
1232 wc_unlock(wc);
1233 return DM_MAPIO_REMAPPED;
1234
1235unlock_remap:
1236 /* make sure that writecache_end_io decrements bio_in_progress: */
1237 bio->bi_private = (void *)1;
1238 atomic_inc(&wc->bio_in_progress[bio_data_dir(bio)]);
1239 wc_unlock(wc);
1240 return DM_MAPIO_REMAPPED;
1241
1242unlock_submit:
1243 wc_unlock(wc);
1244 bio_endio(bio);
1245 return DM_MAPIO_SUBMITTED;
1246
1247unlock_return:
1248 wc_unlock(wc);
1249 return DM_MAPIO_SUBMITTED;
1250
1251unlock_error:
1252 wc_unlock(wc);
1253 bio_io_error(bio);
1254 return DM_MAPIO_SUBMITTED;
1255}
1256
1257static int writecache_end_io(struct dm_target *ti, struct bio *bio, blk_status_t *status)
1258{
1259 struct dm_writecache *wc = ti->private;
1260
1261 if (bio->bi_private != NULL) {
1262 int dir = bio_data_dir(bio);
1263 if (atomic_dec_and_test(&wc->bio_in_progress[dir]))
1264 if (unlikely(waitqueue_active(&wc->bio_in_progress_wait[dir])))
1265 wake_up(&wc->bio_in_progress_wait[dir]);
1266 }
1267 return 0;
1268}
1269
1270static int writecache_iterate_devices(struct dm_target *ti,
1271 iterate_devices_callout_fn fn, void *data)
1272{
1273 struct dm_writecache *wc = ti->private;
1274
1275 return fn(ti, wc->dev, 0, ti->len, data);
1276}
1277
1278static void writecache_io_hints(struct dm_target *ti, struct queue_limits *limits)
1279{
1280 struct dm_writecache *wc = ti->private;
1281
1282 if (limits->logical_block_size < wc->block_size)
1283 limits->logical_block_size = wc->block_size;
1284
1285 if (limits->physical_block_size < wc->block_size)
1286 limits->physical_block_size = wc->block_size;
1287
1288 if (limits->io_min < wc->block_size)
1289 limits->io_min = wc->block_size;
1290}
1291
1292
1293static void writecache_writeback_endio(struct bio *bio)
1294{
1295 struct writeback_struct *wb = container_of(bio, struct writeback_struct, bio);
1296 struct dm_writecache *wc = wb->wc;
1297 unsigned long flags;
1298
1299 raw_spin_lock_irqsave(&wc->endio_list_lock, flags);
1300 if (unlikely(list_empty(&wc->endio_list)))
1301 wake_up_process(wc->endio_thread);
1302 list_add_tail(&wb->endio_entry, &wc->endio_list);
1303 raw_spin_unlock_irqrestore(&wc->endio_list_lock, flags);
1304}
1305
1306static void writecache_copy_endio(int read_err, unsigned long write_err, void *ptr)
1307{
1308 struct copy_struct *c = ptr;
1309 struct dm_writecache *wc = c->wc;
1310
1311 c->error = likely(!(read_err | write_err)) ? 0 : -EIO;
1312
1313 raw_spin_lock_irq(&wc->endio_list_lock);
1314 if (unlikely(list_empty(&wc->endio_list)))
1315 wake_up_process(wc->endio_thread);
1316 list_add_tail(&c->endio_entry, &wc->endio_list);
1317 raw_spin_unlock_irq(&wc->endio_list_lock);
1318}
1319
1320static void __writecache_endio_pmem(struct dm_writecache *wc, struct list_head *list)
1321{
1322 unsigned i;
1323 struct writeback_struct *wb;
1324 struct wc_entry *e;
1325 unsigned long n_walked = 0;
1326
1327 do {
1328 wb = list_entry(list->next, struct writeback_struct, endio_entry);
1329 list_del(&wb->endio_entry);
1330
1331 if (unlikely(wb->bio.bi_status != BLK_STS_OK))
1332 writecache_error(wc, blk_status_to_errno(wb->bio.bi_status),
1333 "write error %d", wb->bio.bi_status);
1334 i = 0;
1335 do {
1336 e = wb->wc_list[i];
1337 BUG_ON(!e->write_in_progress);
1338 e->write_in_progress = false;
1339 INIT_LIST_HEAD(&e->lru);
1340 if (!writecache_has_error(wc))
1341 writecache_free_entry(wc, e);
1342 BUG_ON(!wc->writeback_size);
1343 wc->writeback_size--;
1344 n_walked++;
1345 if (unlikely(n_walked >= ENDIO_LATENCY)) {
1346 writecache_commit_flushed(wc);
1347 wc_unlock(wc);
1348 wc_lock(wc);
1349 n_walked = 0;
1350 }
1351 } while (++i < wb->wc_list_n);
1352
1353 if (wb->wc_list != wb->wc_list_inline)
1354 kfree(wb->wc_list);
1355 bio_put(&wb->bio);
1356 } while (!list_empty(list));
1357}
1358
1359static void __writecache_endio_ssd(struct dm_writecache *wc, struct list_head *list)
1360{
1361 struct copy_struct *c;
1362 struct wc_entry *e;
1363
1364 do {
1365 c = list_entry(list->next, struct copy_struct, endio_entry);
1366 list_del(&c->endio_entry);
1367
1368 if (unlikely(c->error))
1369 writecache_error(wc, c->error, "copy error");
1370
1371 e = c->e;
1372 do {
1373 BUG_ON(!e->write_in_progress);
1374 e->write_in_progress = false;
1375 INIT_LIST_HEAD(&e->lru);
1376 if (!writecache_has_error(wc))
1377 writecache_free_entry(wc, e);
1378
1379 BUG_ON(!wc->writeback_size);
1380 wc->writeback_size--;
1381 e++;
1382 } while (--c->n_entries);
1383 mempool_free(c, &wc->copy_pool);
1384 } while (!list_empty(list));
1385}
1386
1387static int writecache_endio_thread(void *data)
1388{
1389 struct dm_writecache *wc = data;
1390
1391 while (1) {
1392 struct list_head list;
1393
1394 raw_spin_lock_irq(&wc->endio_list_lock);
1395 if (!list_empty(&wc->endio_list))
1396 goto pop_from_list;
1397 set_current_state(TASK_INTERRUPTIBLE);
1398 raw_spin_unlock_irq(&wc->endio_list_lock);
1399
1400 if (unlikely(kthread_should_stop())) {
1401 set_current_state(TASK_RUNNING);
1402 break;
1403 }
1404
1405 schedule();
1406
1407 continue;
1408
1409pop_from_list:
1410 list = wc->endio_list;
1411 list.next->prev = list.prev->next = &list;
1412 INIT_LIST_HEAD(&wc->endio_list);
1413 raw_spin_unlock_irq(&wc->endio_list_lock);
1414
1415 if (!WC_MODE_FUA(wc))
1416 writecache_disk_flush(wc, wc->dev);
1417
1418 wc_lock(wc);
1419
1420 if (WC_MODE_PMEM(wc)) {
1421 __writecache_endio_pmem(wc, &list);
1422 } else {
1423 __writecache_endio_ssd(wc, &list);
1424 writecache_wait_for_ios(wc, READ);
1425 }
1426
1427 writecache_commit_flushed(wc);
1428
1429 wc_unlock(wc);
1430 }
1431
1432 return 0;
1433}
1434
1435static bool wc_add_block(struct writeback_struct *wb, struct wc_entry *e, gfp_t gfp)
1436{
1437 struct dm_writecache *wc = wb->wc;
1438 unsigned block_size = wc->block_size;
1439 void *address = memory_data(wc, e);
1440
1441 persistent_memory_flush_cache(address, block_size);
1442 return bio_add_page(&wb->bio, persistent_memory_page(address),
1443 block_size, persistent_memory_page_offset(address)) != 0;
1444}
1445
1446struct writeback_list {
1447 struct list_head list;
1448 size_t size;
1449};
1450
1451static void __writeback_throttle(struct dm_writecache *wc, struct writeback_list *wbl)
1452{
1453 if (unlikely(wc->max_writeback_jobs)) {
1454 if (READ_ONCE(wc->writeback_size) - wbl->size >= wc->max_writeback_jobs) {
1455 wc_lock(wc);
1456 while (wc->writeback_size - wbl->size >= wc->max_writeback_jobs)
1457 writecache_wait_on_freelist(wc);
1458 wc_unlock(wc);
1459 }
1460 }
1461 cond_resched();
1462}
1463
1464static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeback_list *wbl)
1465{
1466 struct wc_entry *e, *f;
1467 struct bio *bio;
1468 struct writeback_struct *wb;
1469 unsigned max_pages;
1470
1471 while (wbl->size) {
1472 wbl->size--;
1473 e = container_of(wbl->list.prev, struct wc_entry, lru);
1474 list_del(&e->lru);
1475
1476 max_pages = e->wc_list_contiguous;
1477
1478 bio = bio_alloc_bioset(GFP_NOIO, max_pages, &wc->bio_set);
1479 wb = container_of(bio, struct writeback_struct, bio);
1480 wb->wc = wc;
1481 wb->bio.bi_end_io = writecache_writeback_endio;
1482 bio_set_dev(&wb->bio, wc->dev->bdev);
1483 wb->bio.bi_iter.bi_sector = read_original_sector(wc, e);
1484 wb->page_offset = PAGE_SIZE;
1485 if (max_pages <= WB_LIST_INLINE ||
1486 unlikely(!(wb->wc_list = kmalloc_array(max_pages, sizeof(struct wc_entry *),
1487 GFP_NOIO | __GFP_NORETRY |
1488 __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
1489 wb->wc_list = wb->wc_list_inline;
1490 max_pages = WB_LIST_INLINE;
1491 }
1492
1493 BUG_ON(!wc_add_block(wb, e, GFP_NOIO));
1494
1495 wb->wc_list[0] = e;
1496 wb->wc_list_n = 1;
1497
1498 while (wbl->size && wb->wc_list_n < max_pages) {
1499 f = container_of(wbl->list.prev, struct wc_entry, lru);
1500 if (read_original_sector(wc, f) !=
1501 read_original_sector(wc, e) + (wc->block_size >> SECTOR_SHIFT))
1502 break;
1503 if (!wc_add_block(wb, f, GFP_NOWAIT | __GFP_NOWARN))
1504 break;
1505 wbl->size--;
1506 list_del(&f->lru);
1507 wb->wc_list[wb->wc_list_n++] = f;
1508 e = f;
1509 }
1510 bio_set_op_attrs(&wb->bio, REQ_OP_WRITE, WC_MODE_FUA(wc) * REQ_FUA);
1511 if (writecache_has_error(wc)) {
1512 bio->bi_status = BLK_STS_IOERR;
1513 bio_endio(&wb->bio);
1514 } else {
1515 submit_bio(&wb->bio);
1516 }
1517
1518 __writeback_throttle(wc, wbl);
1519 }
1520}
1521
1522static void __writecache_writeback_ssd(struct dm_writecache *wc, struct writeback_list *wbl)
1523{
1524 struct wc_entry *e, *f;
1525 struct dm_io_region from, to;
1526 struct copy_struct *c;
1527
1528 while (wbl->size) {
1529 unsigned n_sectors;
1530
1531 wbl->size--;
1532 e = container_of(wbl->list.prev, struct wc_entry, lru);
1533 list_del(&e->lru);
1534
1535 n_sectors = e->wc_list_contiguous << (wc->block_size_bits - SECTOR_SHIFT);
1536
1537 from.bdev = wc->ssd_dev->bdev;
1538 from.sector = cache_sector(wc, e);
1539 from.count = n_sectors;
1540 to.bdev = wc->dev->bdev;
1541 to.sector = read_original_sector(wc, e);
1542 to.count = n_sectors;
1543
1544 c = mempool_alloc(&wc->copy_pool, GFP_NOIO);
1545 c->wc = wc;
1546 c->e = e;
1547 c->n_entries = e->wc_list_contiguous;
1548
1549 while ((n_sectors -= wc->block_size >> SECTOR_SHIFT)) {
1550 wbl->size--;
1551 f = container_of(wbl->list.prev, struct wc_entry, lru);
1552 BUG_ON(f != e + 1);
1553 list_del(&f->lru);
1554 e = f;
1555 }
1556
1557 dm_kcopyd_copy(wc->dm_kcopyd, &from, 1, &to, 0, writecache_copy_endio, c);
1558
1559 __writeback_throttle(wc, wbl);
1560 }
1561}
1562
1563static void writecache_writeback(struct work_struct *work)
1564{
1565 struct dm_writecache *wc = container_of(work, struct dm_writecache, writeback_work);
1566 struct blk_plug plug;
1567 struct wc_entry *e, *f, *g;
1568 struct rb_node *node, *next_node;
1569 struct list_head skipped;
1570 struct writeback_list wbl;
1571 unsigned long n_walked;
1572
1573 wc_lock(wc);
1574restart:
1575 if (writecache_has_error(wc)) {
1576 wc_unlock(wc);
1577 return;
1578 }
1579
1580 if (unlikely(wc->writeback_all)) {
1581 if (writecache_wait_for_writeback(wc))
1582 goto restart;
1583 }
1584
1585 if (wc->overwrote_committed) {
1586 writecache_wait_for_ios(wc, WRITE);
1587 }
1588
1589 n_walked = 0;
1590 INIT_LIST_HEAD(&skipped);
1591 INIT_LIST_HEAD(&wbl.list);
1592 wbl.size = 0;
1593 while (!list_empty(&wc->lru) &&
1594 (wc->writeback_all ||
1595 wc->freelist_size + wc->writeback_size <= wc->freelist_low_watermark)) {
1596
1597 n_walked++;
1598 if (unlikely(n_walked > WRITEBACK_LATENCY) &&
1599 likely(!wc->writeback_all) && likely(!dm_suspended(wc->ti))) {
1600 queue_work(wc->writeback_wq, &wc->writeback_work);
1601 break;
1602 }
1603
1604 e = container_of(wc->lru.prev, struct wc_entry, lru);
1605 BUG_ON(e->write_in_progress);
1606 if (unlikely(!writecache_entry_is_committed(wc, e))) {
1607 writecache_flush(wc);
1608 }
1609 node = rb_prev(&e->rb_node);
1610 if (node) {
1611 f = container_of(node, struct wc_entry, rb_node);
1612 if (unlikely(read_original_sector(wc, f) ==
1613 read_original_sector(wc, e))) {
1614 BUG_ON(!f->write_in_progress);
1615 list_del(&e->lru);
1616 list_add(&e->lru, &skipped);
1617 cond_resched();
1618 continue;
1619 }
1620 }
1621 wc->writeback_size++;
1622 list_del(&e->lru);
1623 list_add(&e->lru, &wbl.list);
1624 wbl.size++;
1625 e->write_in_progress = true;
1626 e->wc_list_contiguous = 1;
1627
1628 f = e;
1629
1630 while (1) {
1631 next_node = rb_next(&f->rb_node);
1632 if (unlikely(!next_node))
1633 break;
1634 g = container_of(next_node, struct wc_entry, rb_node);
1635 if (read_original_sector(wc, g) ==
1636 read_original_sector(wc, f)) {
1637 f = g;
1638 continue;
1639 }
1640 if (read_original_sector(wc, g) !=
1641 read_original_sector(wc, f) + (wc->block_size >> SECTOR_SHIFT))
1642 break;
1643 if (unlikely(g->write_in_progress))
1644 break;
1645 if (unlikely(!writecache_entry_is_committed(wc, g)))
1646 break;
1647
1648 if (!WC_MODE_PMEM(wc)) {
1649 if (g != f + 1)
1650 break;
1651 }
1652
1653 n_walked++;
1654 //if (unlikely(n_walked > WRITEBACK_LATENCY) && likely(!wc->writeback_all))
1655 // break;
1656
1657 wc->writeback_size++;
1658 list_del(&g->lru);
1659 list_add(&g->lru, &wbl.list);
1660 wbl.size++;
1661 g->write_in_progress = true;
1662 g->wc_list_contiguous = BIO_MAX_PAGES;
1663 f = g;
1664 e->wc_list_contiguous++;
1665 if (unlikely(e->wc_list_contiguous == BIO_MAX_PAGES))
1666 break;
1667 }
1668 cond_resched();
1669 }
1670
1671 if (!list_empty(&skipped)) {
1672 list_splice_tail(&skipped, &wc->lru);
1673 /*
1674 * If we didn't do any progress, we must wait until some
1675 * writeback finishes to avoid burning CPU in a loop
1676 */
1677 if (unlikely(!wbl.size))
1678 writecache_wait_for_writeback(wc);
1679 }
1680
1681 wc_unlock(wc);
1682
1683 blk_start_plug(&plug);
1684
1685 if (WC_MODE_PMEM(wc))
1686 __writecache_writeback_pmem(wc, &wbl);
1687 else
1688 __writecache_writeback_ssd(wc, &wbl);
1689
1690 blk_finish_plug(&plug);
1691
1692 if (unlikely(wc->writeback_all)) {
1693 wc_lock(wc);
1694 while (writecache_wait_for_writeback(wc));
1695 wc_unlock(wc);
1696 }
1697}
1698
1699static int calculate_memory_size(uint64_t device_size, unsigned block_size,
1700 size_t *n_blocks_p, size_t *n_metadata_blocks_p)
1701{
1702 uint64_t n_blocks, offset;
1703 struct wc_entry e;
1704
1705 n_blocks = device_size;
1706 do_div(n_blocks, block_size + sizeof(struct wc_memory_entry));
1707
1708 while (1) {
1709 if (!n_blocks)
1710 return -ENOSPC;
1711 /* Verify the following entries[n_blocks] won't overflow */
1712 if (n_blocks >= ((size_t)-sizeof(struct wc_memory_superblock) /
1713 sizeof(struct wc_memory_entry)))
1714 return -EFBIG;
1715 offset = offsetof(struct wc_memory_superblock, entries[n_blocks]);
1716 offset = (offset + block_size - 1) & ~(uint64_t)(block_size - 1);
1717 if (offset + n_blocks * block_size <= device_size)
1718 break;
1719 n_blocks--;
1720 }
1721
1722 /* check if the bit field overflows */
1723 e.index = n_blocks;
1724 if (e.index != n_blocks)
1725 return -EFBIG;
1726
1727 if (n_blocks_p)
1728 *n_blocks_p = n_blocks;
1729 if (n_metadata_blocks_p)
1730 *n_metadata_blocks_p = offset >> __ffs(block_size);
1731 return 0;
1732}
1733
1734static int init_memory(struct dm_writecache *wc)
1735{
1736 size_t b;
1737 int r;
1738
1739 r = calculate_memory_size(wc->memory_map_size, wc->block_size, &wc->n_blocks, NULL);
1740 if (r)
1741 return r;
1742
1743 r = writecache_alloc_entries(wc);
1744 if (r)
1745 return r;
1746
1747 for (b = 0; b < ARRAY_SIZE(sb(wc)->padding); b++)
1748 pmem_assign(sb(wc)->padding[b], cpu_to_le64(0));
1749 pmem_assign(sb(wc)->version, cpu_to_le32(MEMORY_SUPERBLOCK_VERSION));
1750 pmem_assign(sb(wc)->block_size, cpu_to_le32(wc->block_size));
1751 pmem_assign(sb(wc)->n_blocks, cpu_to_le64(wc->n_blocks));
1752 pmem_assign(sb(wc)->seq_count, cpu_to_le64(0));
1753
1754 for (b = 0; b < wc->n_blocks; b++)
1755 write_original_sector_seq_count(wc, &wc->entries[b], -1, -1);
1756
1757 writecache_flush_all_metadata(wc);
1758 writecache_commit_flushed(wc);
1759 pmem_assign(sb(wc)->magic, cpu_to_le32(MEMORY_SUPERBLOCK_MAGIC));
1760 writecache_flush_region(wc, &sb(wc)->magic, sizeof sb(wc)->magic);
1761 writecache_commit_flushed(wc);
1762
1763 return 0;
1764}
1765
1766static void writecache_dtr(struct dm_target *ti)
1767{
1768 struct dm_writecache *wc = ti->private;
1769
1770 if (!wc)
1771 return;
1772
1773 if (wc->endio_thread)
1774 kthread_stop(wc->endio_thread);
1775
1776 if (wc->flush_thread)
1777 kthread_stop(wc->flush_thread);
1778
1779 bioset_exit(&wc->bio_set);
1780
1781 mempool_exit(&wc->copy_pool);
1782
1783 if (wc->writeback_wq)
1784 destroy_workqueue(wc->writeback_wq);
1785
1786 if (wc->dev)
1787 dm_put_device(ti, wc->dev);
1788
1789 if (wc->ssd_dev)
1790 dm_put_device(ti, wc->ssd_dev);
1791
1792 if (wc->entries)
1793 vfree(wc->entries);
1794
1795 if (wc->memory_map) {
1796 if (WC_MODE_PMEM(wc))
1797 persistent_memory_release(wc);
1798 else
1799 vfree(wc->memory_map);
1800 }
1801
1802 if (wc->dm_kcopyd)
1803 dm_kcopyd_client_destroy(wc->dm_kcopyd);
1804
1805 if (wc->dm_io)
1806 dm_io_client_destroy(wc->dm_io);
1807
1808 if (wc->dirty_bitmap)
1809 vfree(wc->dirty_bitmap);
1810
1811 kfree(wc);
1812}
1813
1814static int writecache_ctr(struct dm_target *ti, unsigned argc, char **argv)
1815{
1816 struct dm_writecache *wc;
1817 struct dm_arg_set as;
1818 const char *string;
1819 unsigned opt_params;
1820 size_t offset, data_size;
1821 int i, r;
1822 char dummy;
1823 int high_wm_percent = HIGH_WATERMARK;
1824 int low_wm_percent = LOW_WATERMARK;
1825 uint64_t x;
1826 struct wc_memory_superblock s;
1827
1828 static struct dm_arg _args[] = {
1829 {0, 10, "Invalid number of feature args"},
1830 };
1831
1832 as.argc = argc;
1833 as.argv = argv;
1834
1835 wc = kzalloc(sizeof(struct dm_writecache), GFP_KERNEL);
1836 if (!wc) {
1837 ti->error = "Cannot allocate writecache structure";
1838 r = -ENOMEM;
1839 goto bad;
1840 }
1841 ti->private = wc;
1842 wc->ti = ti;
1843
1844 mutex_init(&wc->lock);
1845 writecache_poison_lists(wc);
1846 init_waitqueue_head(&wc->freelist_wait);
1847 timer_setup(&wc->autocommit_timer, writecache_autocommit_timer, 0);
1848
1849 for (i = 0; i < 2; i++) {
1850 atomic_set(&wc->bio_in_progress[i], 0);
1851 init_waitqueue_head(&wc->bio_in_progress_wait[i]);
1852 }
1853
1854 wc->dm_io = dm_io_client_create();
1855 if (IS_ERR(wc->dm_io)) {
1856 r = PTR_ERR(wc->dm_io);
1857 ti->error = "Unable to allocate dm-io client";
1858 wc->dm_io = NULL;
1859 goto bad;
1860 }
1861
1862 wc->writeback_wq = alloc_workqueue("writecache-writeback", WQ_MEM_RECLAIM, 1);
1863 if (!wc->writeback_wq) {
1864 r = -ENOMEM;
1865 ti->error = "Could not allocate writeback workqueue";
1866 goto bad;
1867 }
1868 INIT_WORK(&wc->writeback_work, writecache_writeback);
1869 INIT_WORK(&wc->flush_work, writecache_flush_work);
1870
1871 raw_spin_lock_init(&wc->endio_list_lock);
1872 INIT_LIST_HEAD(&wc->endio_list);
1873 wc->endio_thread = kthread_create(writecache_endio_thread, wc, "writecache_endio");
1874 if (IS_ERR(wc->endio_thread)) {
1875 r = PTR_ERR(wc->endio_thread);
1876 wc->endio_thread = NULL;
1877 ti->error = "Couldn't spawn endio thread";
1878 goto bad;
1879 }
1880 wake_up_process(wc->endio_thread);
1881
1882 /*
1883 * Parse the mode (pmem or ssd)
1884 */
1885 string = dm_shift_arg(&as);
1886 if (!string)
1887 goto bad_arguments;
1888
1889 if (!strcasecmp(string, "s")) {
1890 wc->pmem_mode = false;
1891 } else if (!strcasecmp(string, "p")) {
1892#ifdef DM_WRITECACHE_HAS_PMEM
1893 wc->pmem_mode = true;
1894 wc->writeback_fua = true;
1895#else
1896 /*
1897 * If the architecture doesn't support persistent memory or
1898 * the kernel doesn't support any DAX drivers, this driver can
1899 * only be used in SSD-only mode.
1900 */
1901 r = -EOPNOTSUPP;
1902 ti->error = "Persistent memory or DAX not supported on this system";
1903 goto bad;
1904#endif
1905 } else {
1906 goto bad_arguments;
1907 }
1908
1909 if (WC_MODE_PMEM(wc)) {
1910 r = bioset_init(&wc->bio_set, BIO_POOL_SIZE,
1911 offsetof(struct writeback_struct, bio),
1912 BIOSET_NEED_BVECS);
1913 if (r) {
1914 ti->error = "Could not allocate bio set";
1915 goto bad;
1916 }
1917 } else {
1918 r = mempool_init_kmalloc_pool(&wc->copy_pool, 1, sizeof(struct copy_struct));
1919 if (r) {
1920 ti->error = "Could not allocate mempool";
1921 goto bad;
1922 }
1923 }
1924
1925 /*
1926 * Parse the origin data device
1927 */
1928 string = dm_shift_arg(&as);
1929 if (!string)
1930 goto bad_arguments;
1931 r = dm_get_device(ti, string, dm_table_get_mode(ti->table), &wc->dev);
1932 if (r) {
1933 ti->error = "Origin data device lookup failed";
1934 goto bad;
1935 }
1936
1937 /*
1938 * Parse cache data device (be it pmem or ssd)
1939 */
1940 string = dm_shift_arg(&as);
1941 if (!string)
1942 goto bad_arguments;
1943
1944 r = dm_get_device(ti, string, dm_table_get_mode(ti->table), &wc->ssd_dev);
1945 if (r) {
1946 ti->error = "Cache data device lookup failed";
1947 goto bad;
1948 }
1949 wc->memory_map_size = i_size_read(wc->ssd_dev->bdev->bd_inode);
1950
1951 /*
1952 * Parse the cache block size
1953 */
1954 string = dm_shift_arg(&as);
1955 if (!string)
1956 goto bad_arguments;
1957 if (sscanf(string, "%u%c", &wc->block_size, &dummy) != 1 ||
1958 wc->block_size < 512 || wc->block_size > PAGE_SIZE ||
1959 (wc->block_size & (wc->block_size - 1))) {
1960 r = -EINVAL;
1961 ti->error = "Invalid block size";
1962 goto bad;
1963 }
1964 wc->block_size_bits = __ffs(wc->block_size);
1965
1966 wc->max_writeback_jobs = MAX_WRITEBACK_JOBS;
1967 wc->autocommit_blocks = !WC_MODE_PMEM(wc) ? AUTOCOMMIT_BLOCKS_SSD : AUTOCOMMIT_BLOCKS_PMEM;
1968 wc->autocommit_jiffies = msecs_to_jiffies(AUTOCOMMIT_MSEC);
1969
1970 /*
1971 * Parse optional arguments
1972 */
1973 r = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
1974 if (r)
1975 goto bad;
1976
1977 while (opt_params) {
1978 string = dm_shift_arg(&as), opt_params--;
1979 if (!strcasecmp(string, "start_sector") && opt_params >= 1) {
1980 unsigned long long start_sector;
1981 string = dm_shift_arg(&as), opt_params--;
1982 if (sscanf(string, "%llu%c", &start_sector, &dummy) != 1)
1983 goto invalid_optional;
1984 wc->start_sector = start_sector;
1985 if (wc->start_sector != start_sector ||
1986 wc->start_sector >= wc->memory_map_size >> SECTOR_SHIFT)
1987 goto invalid_optional;
1988 } else if (!strcasecmp(string, "high_watermark") && opt_params >= 1) {
1989 string = dm_shift_arg(&as), opt_params--;
1990 if (sscanf(string, "%d%c", &high_wm_percent, &dummy) != 1)
1991 goto invalid_optional;
1992 if (high_wm_percent < 0 || high_wm_percent > 100)
1993 goto invalid_optional;
1994 wc->high_wm_percent_set = true;
1995 } else if (!strcasecmp(string, "low_watermark") && opt_params >= 1) {
1996 string = dm_shift_arg(&as), opt_params--;
1997 if (sscanf(string, "%d%c", &low_wm_percent, &dummy) != 1)
1998 goto invalid_optional;
1999 if (low_wm_percent < 0 || low_wm_percent > 100)
2000 goto invalid_optional;
2001 wc->low_wm_percent_set = true;
2002 } else if (!strcasecmp(string, "writeback_jobs") && opt_params >= 1) {
2003 string = dm_shift_arg(&as), opt_params--;
2004 if (sscanf(string, "%u%c", &wc->max_writeback_jobs, &dummy) != 1)
2005 goto invalid_optional;
2006 wc->max_writeback_jobs_set = true;
2007 } else if (!strcasecmp(string, "autocommit_blocks") && opt_params >= 1) {
2008 string = dm_shift_arg(&as), opt_params--;
2009 if (sscanf(string, "%u%c", &wc->autocommit_blocks, &dummy) != 1)
2010 goto invalid_optional;
2011 wc->autocommit_blocks_set = true;
2012 } else if (!strcasecmp(string, "autocommit_time") && opt_params >= 1) {
2013 unsigned autocommit_msecs;
2014 string = dm_shift_arg(&as), opt_params--;
2015 if (sscanf(string, "%u%c", &autocommit_msecs, &dummy) != 1)
2016 goto invalid_optional;
2017 if (autocommit_msecs > 3600000)
2018 goto invalid_optional;
2019 wc->autocommit_jiffies = msecs_to_jiffies(autocommit_msecs);
2020 wc->autocommit_time_set = true;
2021 } else if (!strcasecmp(string, "fua")) {
2022 if (WC_MODE_PMEM(wc)) {
2023 wc->writeback_fua = true;
2024 wc->writeback_fua_set = true;
2025 } else goto invalid_optional;
2026 } else if (!strcasecmp(string, "nofua")) {
2027 if (WC_MODE_PMEM(wc)) {
2028 wc->writeback_fua = false;
2029 wc->writeback_fua_set = true;
2030 } else goto invalid_optional;
2031 } else {
2032invalid_optional:
2033 r = -EINVAL;
2034 ti->error = "Invalid optional argument";
2035 goto bad;
2036 }
2037 }
2038
2039 if (high_wm_percent < low_wm_percent) {
2040 r = -EINVAL;
2041 ti->error = "High watermark must be greater than or equal to low watermark";
2042 goto bad;
2043 }
2044
2045 if (WC_MODE_PMEM(wc)) {
2046 r = persistent_memory_claim(wc);
2047 if (r) {
2048 ti->error = "Unable to map persistent memory for cache";
2049 goto bad;
2050 }
2051 } else {
2052 struct dm_io_region region;
2053 struct dm_io_request req;
2054 size_t n_blocks, n_metadata_blocks;
2055 uint64_t n_bitmap_bits;
2056
2057 wc->memory_map_size -= (uint64_t)wc->start_sector << SECTOR_SHIFT;
2058
2059 bio_list_init(&wc->flush_list);
2060 wc->flush_thread = kthread_create(writecache_flush_thread, wc, "dm_writecache_flush");
2061 if (IS_ERR(wc->flush_thread)) {
2062 r = PTR_ERR(wc->flush_thread);
2063 wc->flush_thread = NULL;
2064 ti->error = "Couldn't spawn flush thread";
2065 goto bad;
2066 }
2067 wake_up_process(wc->flush_thread);
2068
2069 r = calculate_memory_size(wc->memory_map_size, wc->block_size,
2070 &n_blocks, &n_metadata_blocks);
2071 if (r) {
2072 ti->error = "Invalid device size";
2073 goto bad;
2074 }
2075
2076 n_bitmap_bits = (((uint64_t)n_metadata_blocks << wc->block_size_bits) +
2077 BITMAP_GRANULARITY - 1) / BITMAP_GRANULARITY;
2078 /* this is limitation of test_bit functions */
2079 if (n_bitmap_bits > 1U << 31) {
2080 r = -EFBIG;
2081 ti->error = "Invalid device size";
2082 goto bad;
2083 }
2084
2085 wc->memory_map = vmalloc(n_metadata_blocks << wc->block_size_bits);
2086 if (!wc->memory_map) {
2087 r = -ENOMEM;
2088 ti->error = "Unable to allocate memory for metadata";
2089 goto bad;
2090 }
2091
2092 wc->dm_kcopyd = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2093 if (IS_ERR(wc->dm_kcopyd)) {
2094 r = PTR_ERR(wc->dm_kcopyd);
2095 ti->error = "Unable to allocate dm-kcopyd client";
2096 wc->dm_kcopyd = NULL;
2097 goto bad;
2098 }
2099
2100 wc->metadata_sectors = n_metadata_blocks << (wc->block_size_bits - SECTOR_SHIFT);
2101 wc->dirty_bitmap_size = (n_bitmap_bits + BITS_PER_LONG - 1) /
2102 BITS_PER_LONG * sizeof(unsigned long);
2103 wc->dirty_bitmap = vzalloc(wc->dirty_bitmap_size);
2104 if (!wc->dirty_bitmap) {
2105 r = -ENOMEM;
2106 ti->error = "Unable to allocate dirty bitmap";
2107 goto bad;
2108 }
2109
2110 region.bdev = wc->ssd_dev->bdev;
2111 region.sector = wc->start_sector;
2112 region.count = wc->metadata_sectors;
2113 req.bi_op = REQ_OP_READ;
2114 req.bi_op_flags = REQ_SYNC;
2115 req.mem.type = DM_IO_VMA;
2116 req.mem.ptr.vma = (char *)wc->memory_map;
2117 req.client = wc->dm_io;
2118 req.notify.fn = NULL;
2119
2120 r = dm_io(&req, 1, &region, NULL);
2121 if (r) {
2122 ti->error = "Unable to read metadata";
2123 goto bad;
2124 }
2125 }
2126
2127 r = memcpy_mcsafe(&s, sb(wc), sizeof(struct wc_memory_superblock));
2128 if (r) {
2129 ti->error = "Hardware memory error when reading superblock";
2130 goto bad;
2131 }
2132 if (!le32_to_cpu(s.magic) && !le32_to_cpu(s.version)) {
2133 r = init_memory(wc);
2134 if (r) {
2135 ti->error = "Unable to initialize device";
2136 goto bad;
2137 }
2138 r = memcpy_mcsafe(&s, sb(wc), sizeof(struct wc_memory_superblock));
2139 if (r) {
2140 ti->error = "Hardware memory error when reading superblock";
2141 goto bad;
2142 }
2143 }
2144
2145 if (le32_to_cpu(s.magic) != MEMORY_SUPERBLOCK_MAGIC) {
2146 ti->error = "Invalid magic in the superblock";
2147 r = -EINVAL;
2148 goto bad;
2149 }
2150
2151 if (le32_to_cpu(s.version) != MEMORY_SUPERBLOCK_VERSION) {
2152 ti->error = "Invalid version in the superblock";
2153 r = -EINVAL;
2154 goto bad;
2155 }
2156
2157 if (le32_to_cpu(s.block_size) != wc->block_size) {
2158 ti->error = "Block size does not match superblock";
2159 r = -EINVAL;
2160 goto bad;
2161 }
2162
2163 wc->n_blocks = le64_to_cpu(s.n_blocks);
2164
2165 offset = wc->n_blocks * sizeof(struct wc_memory_entry);
2166 if (offset / sizeof(struct wc_memory_entry) != le64_to_cpu(sb(wc)->n_blocks)) {
2167overflow:
2168 ti->error = "Overflow in size calculation";
2169 r = -EINVAL;
2170 goto bad;
2171 }
2172 offset += sizeof(struct wc_memory_superblock);
2173 if (offset < sizeof(struct wc_memory_superblock))
2174 goto overflow;
2175 offset = (offset + wc->block_size - 1) & ~(size_t)(wc->block_size - 1);
2176 data_size = wc->n_blocks * (size_t)wc->block_size;
2177 if (!offset || (data_size / wc->block_size != wc->n_blocks) ||
2178 (offset + data_size < offset))
2179 goto overflow;
2180 if (offset + data_size > wc->memory_map_size) {
2181 ti->error = "Memory area is too small";
2182 r = -EINVAL;
2183 goto bad;
2184 }
2185
2186 wc->metadata_sectors = offset >> SECTOR_SHIFT;
2187 wc->block_start = (char *)sb(wc) + offset;
2188
2189 x = (uint64_t)wc->n_blocks * (100 - high_wm_percent);
2190 x += 50;
2191 do_div(x, 100);
2192 wc->freelist_high_watermark = x;
2193 x = (uint64_t)wc->n_blocks * (100 - low_wm_percent);
2194 x += 50;
2195 do_div(x, 100);
2196 wc->freelist_low_watermark = x;
2197
2198 r = writecache_alloc_entries(wc);
2199 if (r) {
2200 ti->error = "Cannot allocate memory";
2201 goto bad;
2202 }
2203
2204 ti->num_flush_bios = 1;
2205 ti->flush_supported = true;
2206 ti->num_discard_bios = 1;
2207
2208 if (WC_MODE_PMEM(wc))
2209 persistent_memory_flush_cache(wc->memory_map, wc->memory_map_size);
2210
2211 return 0;
2212
2213bad_arguments:
2214 r = -EINVAL;
2215 ti->error = "Bad arguments";
2216bad:
2217 writecache_dtr(ti);
2218 return r;
2219}
2220
2221static void writecache_status(struct dm_target *ti, status_type_t type,
2222 unsigned status_flags, char *result, unsigned maxlen)
2223{
2224 struct dm_writecache *wc = ti->private;
2225 unsigned extra_args;
2226 unsigned sz = 0;
2227 uint64_t x;
2228
2229 switch (type) {
2230 case STATUSTYPE_INFO:
2231 DMEMIT("%ld %llu %llu %llu", writecache_has_error(wc),
2232 (unsigned long long)wc->n_blocks, (unsigned long long)wc->freelist_size,
2233 (unsigned long long)wc->writeback_size);
2234 break;
2235 case STATUSTYPE_TABLE:
2236 DMEMIT("%c %s %s %u ", WC_MODE_PMEM(wc) ? 'p' : 's',
2237 wc->dev->name, wc->ssd_dev->name, wc->block_size);
2238 extra_args = 0;
2239 if (wc->start_sector)
2240 extra_args += 2;
2241 if (wc->high_wm_percent_set)
2242 extra_args += 2;
2243 if (wc->low_wm_percent_set)
2244 extra_args += 2;
2245 if (wc->max_writeback_jobs_set)
2246 extra_args += 2;
2247 if (wc->autocommit_blocks_set)
2248 extra_args += 2;
2249 if (wc->autocommit_time_set)
2250 extra_args += 2;
2251 if (wc->writeback_fua_set)
2252 extra_args++;
2253
2254 DMEMIT("%u", extra_args);
2255 if (wc->start_sector)
2256 DMEMIT(" start_sector %llu", (unsigned long long)wc->start_sector);
2257 if (wc->high_wm_percent_set) {
2258 x = (uint64_t)wc->freelist_high_watermark * 100;
2259 x += wc->n_blocks / 2;
2260 do_div(x, (size_t)wc->n_blocks);
2261 DMEMIT(" high_watermark %u", 100 - (unsigned)x);
2262 }
2263 if (wc->low_wm_percent_set) {
2264 x = (uint64_t)wc->freelist_low_watermark * 100;
2265 x += wc->n_blocks / 2;
2266 do_div(x, (size_t)wc->n_blocks);
2267 DMEMIT(" low_watermark %u", 100 - (unsigned)x);
2268 }
2269 if (wc->max_writeback_jobs_set)
2270 DMEMIT(" writeback_jobs %u", wc->max_writeback_jobs);
2271 if (wc->autocommit_blocks_set)
2272 DMEMIT(" autocommit_blocks %u", wc->autocommit_blocks);
2273 if (wc->autocommit_time_set)
2274 DMEMIT(" autocommit_time %u", jiffies_to_msecs(wc->autocommit_jiffies));
2275 if (wc->writeback_fua_set)
2276 DMEMIT(" %sfua", wc->writeback_fua ? "" : "no");
2277 break;
2278 }
2279}
2280
2281static struct target_type writecache_target = {
2282 .name = "writecache",
2283 .version = {1, 1, 1},
2284 .module = THIS_MODULE,
2285 .ctr = writecache_ctr,
2286 .dtr = writecache_dtr,
2287 .status = writecache_status,
2288 .postsuspend = writecache_suspend,
2289 .resume = writecache_resume,
2290 .message = writecache_message,
2291 .map = writecache_map,
2292 .end_io = writecache_end_io,
2293 .iterate_devices = writecache_iterate_devices,
2294 .io_hints = writecache_io_hints,
2295};
2296
2297static int __init dm_writecache_init(void)
2298{
2299 int r;
2300
2301 r = dm_register_target(&writecache_target);
2302 if (r < 0) {
2303 DMERR("register failed %d", r);
2304 return r;
2305 }
2306
2307 return 0;
2308}
2309
2310static void __exit dm_writecache_exit(void)
2311{
2312 dm_unregister_target(&writecache_target);
2313}
2314
2315module_init(dm_writecache_init);
2316module_exit(dm_writecache_exit);
2317
2318MODULE_DESCRIPTION(DM_NAME " writecache target");
2319MODULE_AUTHOR("Mikulas Patocka <dm-devel@redhat.com>");
2320MODULE_LICENSE("GPL");
2321