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dm: add writecache target
[linux-2.6-block.git] / drivers / md / dm-writecache.c
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48debafe
MP		 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 void *memory_map;
140 uint64_t memory_map_size;
141 size_t metadata_sectors;
142 size_t n_blocks;
143 uint64_t seq_count;
144 void *block_start;
145 struct wc_entry *entries;
146 unsigned block_size;
147 unsigned char block_size_bits;
148
149 bool pmem_mode:1;
150 bool writeback_fua:1;
151
152 bool overwrote_committed:1;
153 bool memory_vmapped:1;
154
155 bool high_wm_percent_set:1;
156 bool low_wm_percent_set:1;
157 bool max_writeback_jobs_set:1;
158 bool autocommit_blocks_set:1;
159 bool autocommit_time_set:1;
160 bool writeback_fua_set:1;
161 bool flush_on_suspend:1;
162
163 unsigned writeback_all;
164 struct workqueue_struct *writeback_wq;
165 struct work_struct writeback_work;
166 struct work_struct flush_work;
167
168 struct dm_io_client *dm_io;
169
170 raw_spinlock_t endio_list_lock;
171 struct list_head endio_list;
172 struct task_struct *endio_thread;
173
174 struct task_struct *flush_thread;
175 struct bio_list flush_list;
176
177 struct dm_kcopyd_client *dm_kcopyd;
178 unsigned long *dirty_bitmap;
179 unsigned dirty_bitmap_size;
180
181 struct bio_set bio_set;
182 mempool_t copy_pool;
183};
184
185#define WB_LIST_INLINE 16
186
187struct writeback_struct {
188 struct list_head endio_entry;
189 struct dm_writecache *wc;
190 struct wc_entry **wc_list;
191 unsigned wc_list_n;
192 unsigned page_offset;
193 struct page *page;
194 struct wc_entry *wc_list_inline[WB_LIST_INLINE];
195 struct bio bio;
196};
197
198struct copy_struct {
199 struct list_head endio_entry;
200 struct dm_writecache *wc;
201 struct wc_entry *e;
202 unsigned n_entries;
203 int error;
204};
205
206DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(dm_writecache_throttle,
207 "A percentage of time allocated for data copying");
208
209static void wc_lock(struct dm_writecache *wc)
210{
211 mutex_lock(&wc->lock);
212}
213
214static void wc_unlock(struct dm_writecache *wc)
215{
216 mutex_unlock(&wc->lock);
217}
218
219#ifdef DM_WRITECACHE_HAS_PMEM
220static int persistent_memory_claim(struct dm_writecache *wc)
221{
222 int r;
223 loff_t s;
224 long p, da;
225 pfn_t pfn;
226 int id;
227 struct page **pages;
228
229 wc->memory_vmapped = false;
230
231 if (!wc->ssd_dev->dax_dev) {
232 r = -EOPNOTSUPP;
233 goto err1;
234 }
235 s = wc->memory_map_size;
236 p = s >> PAGE_SHIFT;
237 if (!p) {
238 r = -EINVAL;
239 goto err1;
240 }
241 if (p != s >> PAGE_SHIFT) {
242 r = -EOVERFLOW;
243 goto err1;
244 }
245
246 id = dax_read_lock();
247
248 da = dax_direct_access(wc->ssd_dev->dax_dev, 0, p, &wc->memory_map, &pfn);
249 if (da < 0) {
250 wc->memory_map = NULL;
251 r = da;
252 goto err2;
253 }
254 if (!pfn_t_has_page(pfn)) {
255 wc->memory_map = NULL;
256 r = -EOPNOTSUPP;
257 goto err2;
258 }
259 if (da != p) {
260 long i;
261 wc->memory_map = NULL;
262 pages = kvmalloc(p * sizeof(struct page *), GFP_KERNEL);
263 if (!pages) {
264 r = -ENOMEM;
265 goto err2;
266 }
267 i = 0;
268 do {
269 long daa;
270 void *dummy_addr;
271 daa = dax_direct_access(wc->ssd_dev->dax_dev, i, p - i,
272 &dummy_addr, &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 return 0;
297err3:
298 kvfree(pages);
299err2:
300 dax_read_unlock(id);
301err1:
302 return r;
303}
304#else
305static int persistent_memory_claim(struct dm_writecache *wc)
306{
307 BUG();
308}
309#endif
310
311static void persistent_memory_release(struct dm_writecache *wc)
312{
313 if (wc->memory_vmapped)
314 vunmap(wc->memory_map);
315}
316
317static struct page *persistent_memory_page(void *addr)
318{
319 if (is_vmalloc_addr(addr))
320 return vmalloc_to_page(addr);
321 else
322 return virt_to_page(addr);
323}
324
325static unsigned persistent_memory_page_offset(void *addr)
326{
327 return (unsigned long)addr & (PAGE_SIZE - 1);
328}
329
330static void persistent_memory_flush_cache(void *ptr, size_t size)
331{
332 if (is_vmalloc_addr(ptr))
333 flush_kernel_vmap_range(ptr, size);
334}
335
336static void persistent_memory_invalidate_cache(void *ptr, size_t size)
337{
338 if (is_vmalloc_addr(ptr))
339 invalidate_kernel_vmap_range(ptr, size);
340}
341
342static struct wc_memory_superblock *sb(struct dm_writecache *wc)
343{
344 return wc->memory_map;
345}
346
347static struct wc_memory_entry *memory_entry(struct dm_writecache *wc, struct wc_entry *e)
348{
349 if (is_power_of_2(sizeof(struct wc_entry)) && 0)
350 return &sb(wc)->entries[e - wc->entries];
351 else
352 return &sb(wc)->entries[e->index];
353}
354
355static void *memory_data(struct dm_writecache *wc, struct wc_entry *e)
356{
357 return (char *)wc->block_start + (e->index << wc->block_size_bits);
358}
359
360static sector_t cache_sector(struct dm_writecache *wc, struct wc_entry *e)
361{
362 return wc->metadata_sectors +
363 ((sector_t)e->index << (wc->block_size_bits - SECTOR_SHIFT));
364}
365
366static uint64_t read_original_sector(struct dm_writecache *wc, struct wc_entry *e)
367{
368#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
369 return e->original_sector;
370#else
371 return le64_to_cpu(memory_entry(wc, e)->original_sector);
372#endif
373}
374
375static uint64_t read_seq_count(struct dm_writecache *wc, struct wc_entry *e)
376{
377#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
378 return e->seq_count;
379#else
380 return le64_to_cpu(memory_entry(wc, e)->seq_count);
381#endif
382}
383
384static void clear_seq_count(struct dm_writecache *wc, struct wc_entry *e)
385{
386#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
387 e->seq_count = -1;
388#endif
389 pmem_assign(memory_entry(wc, e)->seq_count, cpu_to_le64(-1));
390}
391
392static void write_original_sector_seq_count(struct dm_writecache *wc, struct wc_entry *e,
393 uint64_t original_sector, uint64_t seq_count)
394{
395 struct wc_memory_entry me;
396#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
397 e->original_sector = original_sector;
398 e->seq_count = seq_count;
399#endif
400 me.original_sector = cpu_to_le64(original_sector);
401 me.seq_count = cpu_to_le64(seq_count);
402 pmem_assign(*memory_entry(wc, e), me);
403}
404
405#define writecache_error(wc, err, msg, arg...) \
406do { \
407 if (!cmpxchg(&(wc)->error, 0, err)) \
408 DMERR(msg, ##arg); \
409 wake_up(&(wc)->freelist_wait); \
410} while (0)
411
412#define writecache_has_error(wc) (unlikely(READ_ONCE((wc)->error)))
413
414static void writecache_flush_all_metadata(struct dm_writecache *wc)
415{
416 if (!WC_MODE_PMEM(wc))
417 memset(wc->dirty_bitmap, -1, wc->dirty_bitmap_size);
418}
419
420static void writecache_flush_region(struct dm_writecache *wc, void *ptr, size_t size)
421{
422 if (!WC_MODE_PMEM(wc))
423 __set_bit(((char *)ptr - (char *)wc->memory_map) / BITMAP_GRANULARITY,
424 wc->dirty_bitmap);
425}
426
427static void writecache_disk_flush(struct dm_writecache *wc, struct dm_dev *dev);
428
429struct io_notify {
430 struct dm_writecache *wc;
431 struct completion c;
432 atomic_t count;
433};
434
435static void writecache_notify_io(unsigned long error, void *context)
436{
437 struct io_notify *endio = context;
438
439 if (unlikely(error != 0))
440 writecache_error(endio->wc, -EIO, "error writing metadata");
441 BUG_ON(atomic_read(&endio->count) <= 0);
442 if (atomic_dec_and_test(&endio->count))
443 complete(&endio->c);
444}
445
446static void ssd_commit_flushed(struct dm_writecache *wc)
447{
448 struct dm_io_region region;
449 struct dm_io_request req;
450 struct io_notify endio = {
451 wc,
452 COMPLETION_INITIALIZER_ONSTACK(endio.c),
453 ATOMIC_INIT(1),
454 };
455 unsigned bitmap_bits = wc->dirty_bitmap_size * BITS_PER_LONG;
456 unsigned i = 0;
457
458 while (1) {
459 unsigned j;
460 i = find_next_bit(wc->dirty_bitmap, bitmap_bits, i);
461 if (unlikely(i == bitmap_bits))
462 break;
463 j = find_next_zero_bit(wc->dirty_bitmap, bitmap_bits, i);
464
465 region.bdev = wc->ssd_dev->bdev;
466 region.sector = (sector_t)i * (BITMAP_GRANULARITY >> SECTOR_SHIFT);
467 region.count = (sector_t)(j - i) * (BITMAP_GRANULARITY >> SECTOR_SHIFT);
468
469 if (unlikely(region.sector >= wc->metadata_sectors))
470 break;
471 if (unlikely(region.sector + region.count > wc->metadata_sectors))
472 region.count = wc->metadata_sectors - region.sector;
473
474 atomic_inc(&endio.count);
475 req.bi_op = REQ_OP_WRITE;
476 req.bi_op_flags = REQ_SYNC;
477 req.mem.type = DM_IO_VMA;
478 req.mem.ptr.vma = (char *)wc->memory_map + (size_t)i * BITMAP_GRANULARITY;
479 req.client = wc->dm_io;
480 req.notify.fn = writecache_notify_io;
481 req.notify.context = &endio;
482
483 /* writing via async dm-io (implied by notify.fn above) won't return an error */
484 (void) dm_io(&req, 1, &region, NULL);
485 i = j;
486 }
487
488 writecache_notify_io(0, &endio);
489 wait_for_completion_io(&endio.c);
490
491 writecache_disk_flush(wc, wc->ssd_dev);
492
493 memset(wc->dirty_bitmap, 0, wc->dirty_bitmap_size);
494}
495
496static void writecache_commit_flushed(struct dm_writecache *wc)
497{
498 if (WC_MODE_PMEM(wc))
499 wmb();
500 else
501 ssd_commit_flushed(wc);
502}
503
504static void writecache_disk_flush(struct dm_writecache *wc, struct dm_dev *dev)
505{
506 int r;
507 struct dm_io_region region;
508 struct dm_io_request req;
509
510 region.bdev = dev->bdev;
511 region.sector = 0;
512 region.count = 0;
513 req.bi_op = REQ_OP_WRITE;
514 req.bi_op_flags = REQ_PREFLUSH;
515 req.mem.type = DM_IO_KMEM;
516 req.mem.ptr.addr = NULL;
517 req.client = wc->dm_io;
518 req.notify.fn = NULL;
519
520 r = dm_io(&req, 1, &region, NULL);
521 if (unlikely(r))
522 writecache_error(wc, r, "error flushing metadata: %d", r);
523}
524
525static void writecache_wait_for_ios(struct dm_writecache *wc, int direction)
526{
527 wait_event(wc->bio_in_progress_wait[direction],
528 !atomic_read(&wc->bio_in_progress[direction]));
529}
530
531#define WFE_RETURN_FOLLOWING 1
532#define WFE_LOWEST_SEQ 2
533
534static struct wc_entry *writecache_find_entry(struct dm_writecache *wc,
535 uint64_t block, int flags)
536{
537 struct wc_entry *e;
538 struct rb_node *node = wc->tree.rb_node;
539
540 if (unlikely(!node))
541 return NULL;
542
543 while (1) {
544 e = container_of(node, struct wc_entry, rb_node);
545 if (read_original_sector(wc, e) == block)
546 break;
547 node = (read_original_sector(wc, e) >= block ?
548 e->rb_node.rb_left : e->rb_node.rb_right);
549 if (unlikely(!node)) {
550 if (!(flags & WFE_RETURN_FOLLOWING)) {
551 return NULL;
552 }
553 if (read_original_sector(wc, e) >= block) {
554 break;
555 } else {
556 node = rb_next(&e->rb_node);
557 if (unlikely(!node)) {
558 return NULL;
559 }
560 e = container_of(node, struct wc_entry, rb_node);
561 break;
562 }
563 }
564 }
565
566 while (1) {
567 struct wc_entry *e2;
568 if (flags & WFE_LOWEST_SEQ)
569 node = rb_prev(&e->rb_node);
570 else
571 node = rb_next(&e->rb_node);
572 if (!node)
573 return e;
574 e2 = container_of(node, struct wc_entry, rb_node);
575 if (read_original_sector(wc, e2) != block)
576 return e;
577 e = e2;
578 }
579}
580
581static void writecache_insert_entry(struct dm_writecache *wc, struct wc_entry *ins)
582{
583 struct wc_entry *e;
584 struct rb_node **node = &wc->tree.rb_node, *parent = NULL;
585
586 while (*node) {
587 e = container_of(*node, struct wc_entry, rb_node);
588 parent = &e->rb_node;
589 if (read_original_sector(wc, e) > read_original_sector(wc, ins))
590 node = &parent->rb_left;
591 else
592 node = &parent->rb_right;
593 }
594 rb_link_node(&ins->rb_node, parent, node);
595 rb_insert_color(&ins->rb_node, &wc->tree);
596 list_add(&ins->lru, &wc->lru);
597}
598
599static void writecache_unlink(struct dm_writecache *wc, struct wc_entry *e)
600{
601 list_del(&e->lru);
602 rb_erase(&e->rb_node, &wc->tree);
603}
604
605static void writecache_add_to_freelist(struct dm_writecache *wc, struct wc_entry *e)
606{
607 if (WC_MODE_SORT_FREELIST(wc)) {
608 struct rb_node **node = &wc->freetree.rb_node, *parent = NULL;
609 if (unlikely(!*node))
610 wc->current_free = e;
611 while (*node) {
612 parent = *node;
613 if (&e->rb_node < *node)
614 node = &parent->rb_left;
615 else
616 node = &parent->rb_right;
617 }
618 rb_link_node(&e->rb_node, parent, node);
619 rb_insert_color(&e->rb_node, &wc->freetree);
620 } else {
621 list_add_tail(&e->lru, &wc->freelist);
622 }
623 wc->freelist_size++;
624}
625
626static struct wc_entry *writecache_pop_from_freelist(struct dm_writecache *wc)
627{
628 struct wc_entry *e;
629
630 if (WC_MODE_SORT_FREELIST(wc)) {
631 struct rb_node *next;
632 if (unlikely(!wc->current_free))
633 return NULL;
634 e = wc->current_free;
635 next = rb_next(&e->rb_node);
636 rb_erase(&e->rb_node, &wc->freetree);
637 if (unlikely(!next))
638 next = rb_first(&wc->freetree);
639 wc->current_free = next ? container_of(next, struct wc_entry, rb_node) : NULL;
640 } else {
641 if (unlikely(list_empty(&wc->freelist)))
642 return NULL;
643 e = container_of(wc->freelist.next, struct wc_entry, lru);
644 list_del(&e->lru);
645 }
646 wc->freelist_size--;
647 if (unlikely(wc->freelist_size + wc->writeback_size <= wc->freelist_high_watermark))
648 queue_work(wc->writeback_wq, &wc->writeback_work);
649
650 return e;
651}
652
653static void writecache_free_entry(struct dm_writecache *wc, struct wc_entry *e)
654{
655 writecache_unlink(wc, e);
656 writecache_add_to_freelist(wc, e);
657 clear_seq_count(wc, e);
658 writecache_flush_region(wc, memory_entry(wc, e), sizeof(struct wc_memory_entry));
659 if (unlikely(waitqueue_active(&wc->freelist_wait)))
660 wake_up(&wc->freelist_wait);
661}
662
663static void writecache_wait_on_freelist(struct dm_writecache *wc)
664{
665 DEFINE_WAIT(wait);
666
667 prepare_to_wait(&wc->freelist_wait, &wait, TASK_UNINTERRUPTIBLE);
668 wc_unlock(wc);
669 io_schedule();
670 finish_wait(&wc->freelist_wait, &wait);
671 wc_lock(wc);
672}
673
674static void writecache_poison_lists(struct dm_writecache *wc)
675{
676 /*
677 * Catch incorrect access to these values while the device is suspended.
678 */
679 memset(&wc->tree, -1, sizeof wc->tree);
680 wc->lru.next = LIST_POISON1;
681 wc->lru.prev = LIST_POISON2;
682 wc->freelist.next = LIST_POISON1;
683 wc->freelist.prev = LIST_POISON2;
684}
685
686static void writecache_flush_entry(struct dm_writecache *wc, struct wc_entry *e)
687{
688 writecache_flush_region(wc, memory_entry(wc, e), sizeof(struct wc_memory_entry));
689 if (WC_MODE_PMEM(wc))
690 writecache_flush_region(wc, memory_data(wc, e), wc->block_size);
691}
692
693static bool writecache_entry_is_committed(struct dm_writecache *wc, struct wc_entry *e)
694{
695 return read_seq_count(wc, e) < wc->seq_count;
696}
697
698static void writecache_flush(struct dm_writecache *wc)
699{
700 struct wc_entry *e, *e2;
701 bool need_flush_after_free;
702
703 wc->uncommitted_blocks = 0;
704 del_timer(&wc->autocommit_timer);
705
706 if (list_empty(&wc->lru))
707 return;
708
709 e = container_of(wc->lru.next, struct wc_entry, lru);
710 if (writecache_entry_is_committed(wc, e)) {
711 if (wc->overwrote_committed) {
712 writecache_wait_for_ios(wc, WRITE);
713 writecache_disk_flush(wc, wc->ssd_dev);
714 wc->overwrote_committed = false;
715 }
716 return;
717 }
718 while (1) {
719 writecache_flush_entry(wc, e);
720 if (unlikely(e->lru.next == &wc->lru))
721 break;
722 e2 = container_of(e->lru.next, struct wc_entry, lru);
723 if (writecache_entry_is_committed(wc, e2))
724 break;
725 e = e2;
726 cond_resched();
727 }
728 writecache_commit_flushed(wc);
729
730 writecache_wait_for_ios(wc, WRITE);
731
732 wc->seq_count++;
733 pmem_assign(sb(wc)->seq_count, cpu_to_le64(wc->seq_count));
734 writecache_flush_region(wc, &sb(wc)->seq_count, sizeof sb(wc)->seq_count);
735 writecache_commit_flushed(wc);
736
737 wc->overwrote_committed = false;
738
739 need_flush_after_free = false;
740 while (1) {
741 /* Free another committed entry with lower seq-count */
742 struct rb_node *rb_node = rb_prev(&e->rb_node);
743
744 if (rb_node) {
745 e2 = container_of(rb_node, struct wc_entry, rb_node);
746 if (read_original_sector(wc, e2) == read_original_sector(wc, e) &&
747 likely(!e2->write_in_progress)) {
748 writecache_free_entry(wc, e2);
749 need_flush_after_free = true;
750 }
751 }
752 if (unlikely(e->lru.prev == &wc->lru))
753 break;
754 e = container_of(e->lru.prev, struct wc_entry, lru);
755 cond_resched();
756 }
757
758 if (need_flush_after_free)
759 writecache_commit_flushed(wc);
760}
761
762static void writecache_flush_work(struct work_struct *work)
763{
764 struct dm_writecache *wc = container_of(work, struct dm_writecache, flush_work);
765
766 wc_lock(wc);
767 writecache_flush(wc);
768 wc_unlock(wc);
769}
770
771static void writecache_autocommit_timer(struct timer_list *t)
772{
773 struct dm_writecache *wc = from_timer(wc, t, autocommit_timer);
774 if (!writecache_has_error(wc))
775 queue_work(wc->writeback_wq, &wc->flush_work);
776}
777
778static void writecache_schedule_autocommit(struct dm_writecache *wc)
779{
780 if (!timer_pending(&wc->autocommit_timer))
781 mod_timer(&wc->autocommit_timer, jiffies + wc->autocommit_jiffies);
782}
783
784static void writecache_discard(struct dm_writecache *wc, sector_t start, sector_t end)
785{
786 struct wc_entry *e;
787 bool discarded_something = false;
788
789 e = writecache_find_entry(wc, start, WFE_RETURN_FOLLOWING | WFE_LOWEST_SEQ);
790 if (unlikely(!e))
791 return;
792
793 while (read_original_sector(wc, e) < end) {
794 struct rb_node *node = rb_next(&e->rb_node);
795
796 if (likely(!e->write_in_progress)) {
797 if (!discarded_something) {
798 writecache_wait_for_ios(wc, READ);
799 writecache_wait_for_ios(wc, WRITE);
800 discarded_something = true;
801 }
802 writecache_free_entry(wc, e);
803 }
804
805 if (!node)
806 break;
807
808 e = container_of(node, struct wc_entry, rb_node);
809 }
810
811 if (discarded_something)
812 writecache_commit_flushed(wc);
813}
814
815static bool writecache_wait_for_writeback(struct dm_writecache *wc)
816{
817 if (wc->writeback_size) {
818 writecache_wait_on_freelist(wc);
819 return true;
820 }
821 return false;
822}
823
824static void writecache_suspend(struct dm_target *ti)
825{
826 struct dm_writecache *wc = ti->private;
827 bool flush_on_suspend;
828
829 del_timer_sync(&wc->autocommit_timer);
830
831 wc_lock(wc);
832 writecache_flush(wc);
833 flush_on_suspend = wc->flush_on_suspend;
834 if (flush_on_suspend) {
835 wc->flush_on_suspend = false;
836 wc->writeback_all++;
837 queue_work(wc->writeback_wq, &wc->writeback_work);
838 }
839 wc_unlock(wc);
840
841 flush_workqueue(wc->writeback_wq);
842
843 wc_lock(wc);
844 if (flush_on_suspend)
845 wc->writeback_all--;
846 while (writecache_wait_for_writeback(wc));
847
848 if (WC_MODE_PMEM(wc))
849 persistent_memory_flush_cache(wc->memory_map, wc->memory_map_size);
850
851 writecache_poison_lists(wc);
852
853 wc_unlock(wc);
854}
855
856static int writecache_alloc_entries(struct dm_writecache *wc)
857{
858 size_t b;
859
860 if (wc->entries)
861 return 0;
862 wc->entries = vmalloc(sizeof(struct wc_entry) * wc->n_blocks);
863 if (!wc->entries)
864 return -ENOMEM;
865 for (b = 0; b < wc->n_blocks; b++) {
866 struct wc_entry *e = &wc->entries[b];
867 e->index = b;
868 e->write_in_progress = false;
869 }
870
871 return 0;
872}
873
874static void writecache_resume(struct dm_target *ti)
875{
876 struct dm_writecache *wc = ti->private;
877 size_t b;
878 bool need_flush = false;
879 __le64 sb_seq_count;
880 int r;
881
882 wc_lock(wc);
883
884 if (WC_MODE_PMEM(wc))
885 persistent_memory_invalidate_cache(wc->memory_map, wc->memory_map_size);
886
887 wc->tree = RB_ROOT;
888 INIT_LIST_HEAD(&wc->lru);
889 if (WC_MODE_SORT_FREELIST(wc)) {
890 wc->freetree = RB_ROOT;
891 wc->current_free = NULL;
892 } else {
893 INIT_LIST_HEAD(&wc->freelist);
894 }
895 wc->freelist_size = 0;
896
897 r = memcpy_mcsafe(&sb_seq_count, &sb(wc)->seq_count, sizeof(uint64_t));
898 if (r) {
899 writecache_error(wc, r, "hardware memory error when reading superblock: %d", r);
900 sb_seq_count = cpu_to_le64(0);
901 }
902 wc->seq_count = le64_to_cpu(sb_seq_count);
903
904#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
905 for (b = 0; b < wc->n_blocks; b++) {
906 struct wc_entry *e = &wc->entries[b];
907 struct wc_memory_entry wme;
908 if (writecache_has_error(wc)) {
909 e->original_sector = -1;
910 e->seq_count = -1;
911 continue;
912 }
913 r = memcpy_mcsafe(&wme, memory_entry(wc, e), sizeof(struct wc_memory_entry));
914 if (r) {
915 writecache_error(wc, r, "hardware memory error when reading metadata entry %lu: %d",
916 (unsigned long)b, r);
917 e->original_sector = -1;
918 e->seq_count = -1;
919 } else {
920 e->original_sector = le64_to_cpu(wme.original_sector);
921 e->seq_count = le64_to_cpu(wme.seq_count);
922 }
923 }
924#endif
925 for (b = 0; b < wc->n_blocks; b++) {
926 struct wc_entry *e = &wc->entries[b];
927 if (!writecache_entry_is_committed(wc, e)) {
928 if (read_seq_count(wc, e) != -1) {
929erase_this:
930 clear_seq_count(wc, e);
931 need_flush = true;
932 }
933 writecache_add_to_freelist(wc, e);
934 } else {
935 struct wc_entry *old;
936
937 old = writecache_find_entry(wc, read_original_sector(wc, e), 0);
938 if (!old) {
939 writecache_insert_entry(wc, e);
940 } else {
941 if (read_seq_count(wc, old) == read_seq_count(wc, e)) {
942 writecache_error(wc, -EINVAL,
943 "two identical entries, position %llu, sector %llu, sequence %llu",
944 (unsigned long long)b, (unsigned long long)read_original_sector(wc, e),
945 (unsigned long long)read_seq_count(wc, e));
946 }
947 if (read_seq_count(wc, old) > read_seq_count(wc, e)) {
948 goto erase_this;
949 } else {
950 writecache_free_entry(wc, old);
951 writecache_insert_entry(wc, e);
952 need_flush = true;
953 }
954 }
955 }
956 cond_resched();
957 }
958
959 if (need_flush) {
960 writecache_flush_all_metadata(wc);
961 writecache_commit_flushed(wc);
962 }
963
964 wc_unlock(wc);
965}
966
967static int process_flush_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
968{
969 if (argc != 1)
970 return -EINVAL;
971
972 wc_lock(wc);
973 if (dm_suspended(wc->ti)) {
974 wc_unlock(wc);
975 return -EBUSY;
976 }
977 if (writecache_has_error(wc)) {
978 wc_unlock(wc);
979 return -EIO;
980 }
981
982 writecache_flush(wc);
983 wc->writeback_all++;
984 queue_work(wc->writeback_wq, &wc->writeback_work);
985 wc_unlock(wc);
986
987 flush_workqueue(wc->writeback_wq);
988
989 wc_lock(wc);
990 wc->writeback_all--;
991 if (writecache_has_error(wc)) {
992 wc_unlock(wc);
993 return -EIO;
994 }
995 wc_unlock(wc);
996
997 return 0;
998}
999
1000static int process_flush_on_suspend_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
1001{
1002 if (argc != 1)
1003 return -EINVAL;
1004
1005 wc_lock(wc);
1006 wc->flush_on_suspend = true;
1007 wc_unlock(wc);
1008
1009 return 0;
1010}
1011
1012static int writecache_message(struct dm_target *ti, unsigned argc, char **argv,
1013 char *result, unsigned maxlen)
1014{
1015 int r = -EINVAL;
1016 struct dm_writecache *wc = ti->private;
1017
1018 if (!strcasecmp(argv[0], "flush"))
1019 r = process_flush_mesg(argc, argv, wc);
1020 else if (!strcasecmp(argv[0], "flush_on_suspend"))
1021 r = process_flush_on_suspend_mesg(argc, argv, wc);
1022 else
1023 DMERR("unrecognised message received: %s", argv[0]);
1024
1025 return r;
1026}
1027
1028static void bio_copy_block(struct dm_writecache *wc, struct bio *bio, void *data)
1029{
1030 void *buf;
1031 unsigned long flags;
1032 unsigned size;
1033 int rw = bio_data_dir(bio);
1034 unsigned remaining_size = wc->block_size;
1035
1036 do {
1037 struct bio_vec bv = bio_iter_iovec(bio, bio->bi_iter);
1038 buf = bvec_kmap_irq(&bv, &flags);
1039 size = bv.bv_len;
1040 if (unlikely(size > remaining_size))
1041 size = remaining_size;
1042
1043 if (rw == READ) {
1044 int r;
1045 r = memcpy_mcsafe(buf, data, size);
1046 flush_dcache_page(bio_page(bio));
1047 if (unlikely(r)) {
1048 writecache_error(wc, r, "hardware memory error when reading data: %d", r);
1049 bio->bi_status = BLK_STS_IOERR;
1050 }
1051 } else {
1052 flush_dcache_page(bio_page(bio));
1053 memcpy_flushcache(data, buf, size);
1054 }
1055
1056 bvec_kunmap_irq(buf, &flags);
1057
1058 data = (char *)data + size;
1059 remaining_size -= size;
1060 bio_advance(bio, size);
1061 } while (unlikely(remaining_size));
1062}
1063
1064static int writecache_flush_thread(void *data)
1065{
1066 struct dm_writecache *wc = data;
1067
1068 while (1) {
1069 struct bio *bio;
1070
1071 wc_lock(wc);
1072 bio = bio_list_pop(&wc->flush_list);
1073 if (!bio) {
1074 set_current_state(TASK_INTERRUPTIBLE);
1075 wc_unlock(wc);
1076
1077 if (unlikely(kthread_should_stop())) {
1078 set_current_state(TASK_RUNNING);
1079 break;
1080 }
1081
1082 schedule();
1083 continue;
1084 }
1085
1086 if (bio_op(bio) == REQ_OP_DISCARD) {
1087 writecache_discard(wc, bio->bi_iter.bi_sector,
1088 bio_end_sector(bio));
1089 wc_unlock(wc);
1090 bio_set_dev(bio, wc->dev->bdev);
1091 generic_make_request(bio);
1092 } else {
1093 writecache_flush(wc);
1094 wc_unlock(wc);
1095 if (writecache_has_error(wc))
1096 bio->bi_status = BLK_STS_IOERR;
1097 bio_endio(bio);
1098 }
1099 }
1100
1101 return 0;
1102}
1103
1104static void writecache_offload_bio(struct dm_writecache *wc, struct bio *bio)
1105{
1106 if (bio_list_empty(&wc->flush_list))
1107 wake_up_process(wc->flush_thread);
1108 bio_list_add(&wc->flush_list, bio);
1109}
1110
1111static int writecache_map(struct dm_target *ti, struct bio *bio)
1112{
1113 struct wc_entry *e;
1114 struct dm_writecache *wc = ti->private;
1115
1116 bio->bi_private = NULL;
1117
1118 wc_lock(wc);
1119
1120 if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
1121 if (writecache_has_error(wc))
1122 goto unlock_error;
1123 if (WC_MODE_PMEM(wc)) {
1124 writecache_flush(wc);
1125 if (writecache_has_error(wc))
1126 goto unlock_error;
1127 goto unlock_submit;
1128 } else {
1129 writecache_offload_bio(wc, bio);
1130 goto unlock_return;
1131 }
1132 }
1133
1134 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
1135
1136 if (unlikely((((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) &
1137 (wc->block_size / 512 - 1)) != 0)) {
1138 DMERR("I/O is not aligned, sector %llu, size %u, block size %u",
1139 (unsigned long long)bio->bi_iter.bi_sector,
1140 bio->bi_iter.bi_size, wc->block_size);
1141 goto unlock_error;
1142 }
1143
1144 if (unlikely(bio_op(bio) == REQ_OP_DISCARD)) {
1145 if (writecache_has_error(wc))
1146 goto unlock_error;
1147 if (WC_MODE_PMEM(wc)) {
1148 writecache_discard(wc, bio->bi_iter.bi_sector, bio_end_sector(bio));
1149 goto unlock_remap_origin;
1150 } else {
1151 writecache_offload_bio(wc, bio);
1152 goto unlock_return;
1153 }
1154 }
1155
1156 if (bio_data_dir(bio) == READ) {
1157read_next_block:
1158 e = writecache_find_entry(wc, bio->bi_iter.bi_sector, WFE_RETURN_FOLLOWING);
1159 if (e && read_original_sector(wc, e) == bio->bi_iter.bi_sector) {
1160 if (WC_MODE_PMEM(wc)) {
1161 bio_copy_block(wc, bio, memory_data(wc, e));
1162 if (bio->bi_iter.bi_size)
1163 goto read_next_block;
1164 goto unlock_submit;
1165 } else {
1166 dm_accept_partial_bio(bio, wc->block_size >> SECTOR_SHIFT);
1167 bio_set_dev(bio, wc->ssd_dev->bdev);
1168 bio->bi_iter.bi_sector = cache_sector(wc, e);
1169 if (!writecache_entry_is_committed(wc, e))
1170 writecache_wait_for_ios(wc, WRITE);
1171 goto unlock_remap;
1172 }
1173 } else {
1174 if (e) {
1175 sector_t next_boundary =
1176 read_original_sector(wc, e) - bio->bi_iter.bi_sector;
1177 if (next_boundary < bio->bi_iter.bi_size >> SECTOR_SHIFT) {
1178 dm_accept_partial_bio(bio, next_boundary);
1179 }
1180 }
1181 goto unlock_remap_origin;
1182 }
1183 } else {
1184 do {
1185 if (writecache_has_error(wc))
1186 goto unlock_error;
1187 e = writecache_find_entry(wc, bio->bi_iter.bi_sector, 0);
1188 if (e) {
1189 if (!writecache_entry_is_committed(wc, e))
1190 goto bio_copy;
1191 if (!WC_MODE_PMEM(wc) && !e->write_in_progress) {
1192 wc->overwrote_committed = true;
1193 goto bio_copy;
1194 }
1195 }
1196 e = writecache_pop_from_freelist(wc);
1197 if (unlikely(!e)) {
1198 writecache_wait_on_freelist(wc);
1199 continue;
1200 }
1201 write_original_sector_seq_count(wc, e, bio->bi_iter.bi_sector, wc->seq_count);
1202 writecache_insert_entry(wc, e);
1203 wc->uncommitted_blocks++;
1204bio_copy:
1205 if (WC_MODE_PMEM(wc)) {
1206 bio_copy_block(wc, bio, memory_data(wc, e));
1207 } else {
1208 dm_accept_partial_bio(bio, wc->block_size >> SECTOR_SHIFT);
1209 bio_set_dev(bio, wc->ssd_dev->bdev);
1210 bio->bi_iter.bi_sector = cache_sector(wc, e);
1211 if (unlikely(wc->uncommitted_blocks >= wc->autocommit_blocks)) {
1212 wc->uncommitted_blocks = 0;
1213 queue_work(wc->writeback_wq, &wc->flush_work);
1214 } else {
1215 writecache_schedule_autocommit(wc);
1216 }
1217 goto unlock_remap;
1218 }
1219 } while (bio->bi_iter.bi_size);
1220
1221 if (unlikely(wc->uncommitted_blocks >= wc->autocommit_blocks))
1222 writecache_flush(wc);
1223 else
1224 writecache_schedule_autocommit(wc);
1225 goto unlock_submit;
1226 }
1227
1228unlock_remap_origin:
1229 bio_set_dev(bio, wc->dev->bdev);
1230 wc_unlock(wc);
1231 return DM_MAPIO_REMAPPED;
1232
1233unlock_remap:
1234 /* make sure that writecache_end_io decrements bio_in_progress: */
1235 bio->bi_private = (void *)1;
1236 atomic_inc(&wc->bio_in_progress[bio_data_dir(bio)]);
1237 wc_unlock(wc);
1238 return DM_MAPIO_REMAPPED;
1239
1240unlock_submit:
1241 wc_unlock(wc);
1242 bio_endio(bio);
1243 return DM_MAPIO_SUBMITTED;
1244
1245unlock_return:
1246 wc_unlock(wc);
1247 return DM_MAPIO_SUBMITTED;
1248
1249unlock_error:
1250 wc_unlock(wc);
1251 bio_io_error(bio);
1252 return DM_MAPIO_SUBMITTED;
1253}
1254
1255static int writecache_end_io(struct dm_target *ti, struct bio *bio, blk_status_t *status)
1256{
1257 struct dm_writecache *wc = ti->private;
1258
1259 if (bio->bi_private != NULL) {
1260 int dir = bio_data_dir(bio);
1261 if (atomic_dec_and_test(&wc->bio_in_progress[dir]))
1262 if (unlikely(waitqueue_active(&wc->bio_in_progress_wait[dir])))
1263 wake_up(&wc->bio_in_progress_wait[dir]);
1264 }
1265 return 0;
1266}
1267
1268static int writecache_iterate_devices(struct dm_target *ti,
1269 iterate_devices_callout_fn fn, void *data)
1270{
1271 struct dm_writecache *wc = ti->private;
1272
1273 return fn(ti, wc->dev, 0, ti->len, data);
1274}
1275
1276static void writecache_io_hints(struct dm_target *ti, struct queue_limits *limits)
1277{
1278 struct dm_writecache *wc = ti->private;
1279
1280 if (limits->logical_block_size < wc->block_size)
1281 limits->logical_block_size = wc->block_size;
1282
1283 if (limits->physical_block_size < wc->block_size)
1284 limits->physical_block_size = wc->block_size;
1285
1286 if (limits->io_min < wc->block_size)
1287 limits->io_min = wc->block_size;
1288}
1289
1290
1291static void writecache_writeback_endio(struct bio *bio)
1292{
1293 struct writeback_struct *wb = container_of(bio, struct writeback_struct, bio);
1294 struct dm_writecache *wc = wb->wc;
1295 unsigned long flags;
1296
1297 raw_spin_lock_irqsave(&wc->endio_list_lock, flags);
1298 if (unlikely(list_empty(&wc->endio_list)))
1299 wake_up_process(wc->endio_thread);
1300 list_add_tail(&wb->endio_entry, &wc->endio_list);
1301 raw_spin_unlock_irqrestore(&wc->endio_list_lock, flags);
1302}
1303
1304static void writecache_copy_endio(int read_err, unsigned long write_err, void *ptr)
1305{
1306 struct copy_struct *c = ptr;
1307 struct dm_writecache *wc = c->wc;
1308
1309 c->error = likely(!(read_err | write_err)) ? 0 : -EIO;
1310
1311 raw_spin_lock_irq(&wc->endio_list_lock);
1312 if (unlikely(list_empty(&wc->endio_list)))
1313 wake_up_process(wc->endio_thread);
1314 list_add_tail(&c->endio_entry, &wc->endio_list);
1315 raw_spin_unlock_irq(&wc->endio_list_lock);
1316}
1317
1318static void __writecache_endio_pmem(struct dm_writecache *wc, struct list_head *list)
1319{
1320 unsigned i;
1321 struct writeback_struct *wb;
1322 struct wc_entry *e;
1323 unsigned long n_walked = 0;
1324
1325 do {
1326 wb = list_entry(list->next, struct writeback_struct, endio_entry);
1327 list_del(&wb->endio_entry);
1328
1329 if (unlikely(wb->bio.bi_status != BLK_STS_OK))
1330 writecache_error(wc, blk_status_to_errno(wb->bio.bi_status),
1331 "write error %d", wb->bio.bi_status);
1332 i = 0;
1333 do {
1334 e = wb->wc_list[i];
1335 BUG_ON(!e->write_in_progress);
1336 e->write_in_progress = false;
1337 INIT_LIST_HEAD(&e->lru);
1338 if (!writecache_has_error(wc))
1339 writecache_free_entry(wc, e);
1340 BUG_ON(!wc->writeback_size);
1341 wc->writeback_size--;
1342 n_walked++;
1343 if (unlikely(n_walked >= ENDIO_LATENCY)) {
1344 writecache_commit_flushed(wc);
1345 wc_unlock(wc);
1346 wc_lock(wc);
1347 n_walked = 0;
1348 }
1349 } while (++i < wb->wc_list_n);
1350
1351 if (wb->wc_list != wb->wc_list_inline)
1352 kfree(wb->wc_list);
1353 bio_put(&wb->bio);
1354 } while (!list_empty(list));
1355}
1356
1357static void __writecache_endio_ssd(struct dm_writecache *wc, struct list_head *list)
1358{
1359 struct copy_struct *c;
1360 struct wc_entry *e;
1361
1362 do {
1363 c = list_entry(list->next, struct copy_struct, endio_entry);
1364 list_del(&c->endio_entry);
1365
1366 if (unlikely(c->error))
1367 writecache_error(wc, c->error, "copy error");
1368
1369 e = c->e;
1370 do {
1371 BUG_ON(!e->write_in_progress);
1372 e->write_in_progress = false;
1373 INIT_LIST_HEAD(&e->lru);
1374 if (!writecache_has_error(wc))
1375 writecache_free_entry(wc, e);
1376
1377 BUG_ON(!wc->writeback_size);
1378 wc->writeback_size--;
1379 e++;
1380 } while (--c->n_entries);
1381 mempool_free(c, &wc->copy_pool);
1382 } while (!list_empty(list));
1383}
1384
1385static int writecache_endio_thread(void *data)
1386{
1387 struct dm_writecache *wc = data;
1388
1389 while (1) {
1390 struct list_head list;
1391
1392 raw_spin_lock_irq(&wc->endio_list_lock);
1393 if (!list_empty(&wc->endio_list))
1394 goto pop_from_list;
1395 set_current_state(TASK_INTERRUPTIBLE);
1396 raw_spin_unlock_irq(&wc->endio_list_lock);
1397
1398 if (unlikely(kthread_should_stop())) {
1399 set_current_state(TASK_RUNNING);
1400 break;
1401 }
1402
1403 schedule();
1404
1405 continue;
1406
1407pop_from_list:
1408 list = wc->endio_list;
1409 list.next->prev = list.prev->next = &list;
1410 INIT_LIST_HEAD(&wc->endio_list);
1411 raw_spin_unlock_irq(&wc->endio_list_lock);
1412
1413 if (!WC_MODE_FUA(wc))
1414 writecache_disk_flush(wc, wc->dev);
1415
1416 wc_lock(wc);
1417
1418 if (WC_MODE_PMEM(wc)) {
1419 __writecache_endio_pmem(wc, &list);
1420 } else {
1421 __writecache_endio_ssd(wc, &list);
1422 writecache_wait_for_ios(wc, READ);
1423 }
1424
1425 writecache_commit_flushed(wc);
1426
1427 wc_unlock(wc);
1428 }
1429
1430 return 0;
1431}
1432
1433static bool wc_add_block(struct writeback_struct *wb, struct wc_entry *e, gfp_t gfp)
1434{
1435 struct dm_writecache *wc = wb->wc;
1436 unsigned block_size = wc->block_size;
1437 void *address = memory_data(wc, e);
1438
1439 persistent_memory_flush_cache(address, block_size);
1440 return bio_add_page(&wb->bio, persistent_memory_page(address),
1441 block_size, persistent_memory_page_offset(address)) != 0;
1442}
1443
1444struct writeback_list {
1445 struct list_head list;
1446 size_t size;
1447};
1448
1449static void __writeback_throttle(struct dm_writecache *wc, struct writeback_list *wbl)
1450{
1451 if (unlikely(wc->max_writeback_jobs)) {
1452 if (READ_ONCE(wc->writeback_size) - wbl->size >= wc->max_writeback_jobs) {
1453 wc_lock(wc);
1454 while (wc->writeback_size - wbl->size >= wc->max_writeback_jobs)
1455 writecache_wait_on_freelist(wc);
1456 wc_unlock(wc);
1457 }
1458 }
1459 cond_resched();
1460}
1461
1462static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeback_list *wbl)
1463{
1464 struct wc_entry *e, *f;
1465 struct bio *bio;
1466 struct writeback_struct *wb;
1467 unsigned max_pages;
1468
1469 while (wbl->size) {
1470 wbl->size--;
1471 e = container_of(wbl->list.prev, struct wc_entry, lru);
1472 list_del(&e->lru);
1473
1474 max_pages = e->wc_list_contiguous;
1475
1476 bio = bio_alloc_bioset(GFP_NOIO, max_pages, &wc->bio_set);
1477 wb = container_of(bio, struct writeback_struct, bio);
1478 wb->wc = wc;
1479 wb->bio.bi_end_io = writecache_writeback_endio;
1480 bio_set_dev(&wb->bio, wc->dev->bdev);
1481 wb->bio.bi_iter.bi_sector = read_original_sector(wc, e);
1482 wb->page_offset = PAGE_SIZE;
1483 if (max_pages <= WB_LIST_INLINE ||
1484 unlikely(!(wb->wc_list = kmalloc(max_pages * sizeof(struct wc_entry *),
1485 GFP_NOIO | __GFP_NORETRY |
1486 __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
1487 wb->wc_list = wb->wc_list_inline;
1488 max_pages = WB_LIST_INLINE;
1489 }
1490
1491 BUG_ON(!wc_add_block(wb, e, GFP_NOIO));
1492
1493 wb->wc_list[0] = e;
1494 wb->wc_list_n = 1;
1495
1496 while (wbl->size && wb->wc_list_n < max_pages) {
1497 f = container_of(wbl->list.prev, struct wc_entry, lru);
1498 if (read_original_sector(wc, f) !=
1499 read_original_sector(wc, e) + (wc->block_size >> SECTOR_SHIFT))
1500 break;
1501 if (!wc_add_block(wb, f, GFP_NOWAIT | __GFP_NOWARN))
1502 break;
1503 wbl->size--;
1504 list_del(&f->lru);
1505 wb->wc_list[wb->wc_list_n++] = f;
1506 e = f;
1507 }
1508 bio_set_op_attrs(&wb->bio, REQ_OP_WRITE, WC_MODE_FUA(wc) * REQ_FUA);
1509 if (writecache_has_error(wc)) {
1510 bio->bi_status = BLK_STS_IOERR;
1511 bio_endio(&wb->bio);
1512 } else {
1513 submit_bio(&wb->bio);
1514 }
1515
1516 __writeback_throttle(wc, wbl);
1517 }
1518}
1519
1520static void __writecache_writeback_ssd(struct dm_writecache *wc, struct writeback_list *wbl)
1521{
1522 struct wc_entry *e, *f;
1523 struct dm_io_region from, to;
1524 struct copy_struct *c;
1525
1526 while (wbl->size) {
1527 unsigned n_sectors;
1528
1529 wbl->size--;
1530 e = container_of(wbl->list.prev, struct wc_entry, lru);
1531 list_del(&e->lru);
1532
1533 n_sectors = e->wc_list_contiguous << (wc->block_size_bits - SECTOR_SHIFT);
1534
1535 from.bdev = wc->ssd_dev->bdev;
1536 from.sector = cache_sector(wc, e);
1537 from.count = n_sectors;
1538 to.bdev = wc->dev->bdev;
1539 to.sector = read_original_sector(wc, e);
1540 to.count = n_sectors;
1541
1542 c = mempool_alloc(&wc->copy_pool, GFP_NOIO);
1543 c->wc = wc;
1544 c->e = e;
1545 c->n_entries = e->wc_list_contiguous;
1546
1547 while ((n_sectors -= wc->block_size >> SECTOR_SHIFT)) {
1548 wbl->size--;
1549 f = container_of(wbl->list.prev, struct wc_entry, lru);
1550 BUG_ON(f != e + 1);
1551 list_del(&f->lru);
1552 e = f;
1553 }
1554
1555 dm_kcopyd_copy(wc->dm_kcopyd, &from, 1, &to, 0, writecache_copy_endio, c);
1556
1557 __writeback_throttle(wc, wbl);
1558 }
1559}
1560
1561static void writecache_writeback(struct work_struct *work)
1562{
1563 struct dm_writecache *wc = container_of(work, struct dm_writecache, writeback_work);
1564 struct blk_plug plug;
1565 struct wc_entry *e, *f, *g;
1566 struct rb_node *node, *next_node;
1567 struct list_head skipped;
1568 struct writeback_list wbl;
1569 unsigned long n_walked;
1570
1571 wc_lock(wc);
1572restart:
1573 if (writecache_has_error(wc)) {
1574 wc_unlock(wc);
1575 return;
1576 }
1577
1578 if (unlikely(wc->writeback_all)) {
1579 if (writecache_wait_for_writeback(wc))
1580 goto restart;
1581 }
1582
1583 if (wc->overwrote_committed) {
1584 writecache_wait_for_ios(wc, WRITE);
1585 }
1586
1587 n_walked = 0;
1588 INIT_LIST_HEAD(&skipped);
1589 INIT_LIST_HEAD(&wbl.list);
1590 wbl.size = 0;
1591 while (!list_empty(&wc->lru) &&
1592 (wc->writeback_all ||
1593 wc->freelist_size + wc->writeback_size <= wc->freelist_low_watermark)) {
1594
1595 n_walked++;
1596 if (unlikely(n_walked > WRITEBACK_LATENCY) &&
1597 likely(!wc->writeback_all) && likely(!dm_suspended(wc->ti))) {
1598 queue_work(wc->writeback_wq, &wc->writeback_work);
1599 break;
1600 }
1601
1602 e = container_of(wc->lru.prev, struct wc_entry, lru);
1603 BUG_ON(e->write_in_progress);
1604 if (unlikely(!writecache_entry_is_committed(wc, e))) {
1605 writecache_flush(wc);
1606 }
1607 node = rb_prev(&e->rb_node);
1608 if (node) {
1609 f = container_of(node, struct wc_entry, rb_node);
1610 if (unlikely(read_original_sector(wc, f) ==
1611 read_original_sector(wc, e))) {
1612 BUG_ON(!f->write_in_progress);
1613 list_del(&e->lru);
1614 list_add(&e->lru, &skipped);
1615 cond_resched();
1616 continue;
1617 }
1618 }
1619 wc->writeback_size++;
1620 list_del(&e->lru);
1621 list_add(&e->lru, &wbl.list);
1622 wbl.size++;
1623 e->write_in_progress = true;
1624 e->wc_list_contiguous = 1;
1625
1626 f = e;
1627
1628 while (1) {
1629 next_node = rb_next(&f->rb_node);
1630 if (unlikely(!next_node))
1631 break;
1632 g = container_of(next_node, struct wc_entry, rb_node);
1633 if (read_original_sector(wc, g) ==
1634 read_original_sector(wc, f)) {
1635 f = g;
1636 continue;
1637 }
1638 if (read_original_sector(wc, g) !=
1639 read_original_sector(wc, f) + (wc->block_size >> SECTOR_SHIFT))
1640 break;
1641 if (unlikely(g->write_in_progress))
1642 break;
1643 if (unlikely(!writecache_entry_is_committed(wc, g)))
1644 break;
1645
1646 if (!WC_MODE_PMEM(wc)) {
1647 if (g != f + 1)
1648 break;
1649 }
1650
1651 n_walked++;
1652 //if (unlikely(n_walked > WRITEBACK_LATENCY) && likely(!wc->writeback_all))
1653 // break;
1654
1655 wc->writeback_size++;
1656 list_del(&g->lru);
1657 list_add(&g->lru, &wbl.list);
1658 wbl.size++;
1659 g->write_in_progress = true;
1660 g->wc_list_contiguous = BIO_MAX_PAGES;
1661 f = g;
1662 e->wc_list_contiguous++;
1663 if (unlikely(e->wc_list_contiguous == BIO_MAX_PAGES))
1664 break;
1665 }
1666 cond_resched();
1667 }
1668
1669 if (!list_empty(&skipped)) {
1670 list_splice_tail(&skipped, &wc->lru);
1671 /*
1672 * If we didn't do any progress, we must wait until some
1673 * writeback finishes to avoid burning CPU in a loop
1674 */
1675 if (unlikely(!wbl.size))
1676 writecache_wait_for_writeback(wc);
1677 }
1678
1679 wc_unlock(wc);
1680
1681 blk_start_plug(&plug);
1682
1683 if (WC_MODE_PMEM(wc))
1684 __writecache_writeback_pmem(wc, &wbl);
1685 else
1686 __writecache_writeback_ssd(wc, &wbl);
1687
1688 blk_finish_plug(&plug);
1689
1690 if (unlikely(wc->writeback_all)) {
1691 wc_lock(wc);
1692 while (writecache_wait_for_writeback(wc));
1693 wc_unlock(wc);
1694 }
1695}
1696
1697static int calculate_memory_size(uint64_t device_size, unsigned block_size,
1698 size_t *n_blocks_p, size_t *n_metadata_blocks_p)
1699{
1700 uint64_t n_blocks, offset;
1701 struct wc_entry e;
1702
1703 n_blocks = device_size;
1704 do_div(n_blocks, block_size + sizeof(struct wc_memory_entry));
1705
1706 while (1) {
1707 if (!n_blocks)
1708 return -ENOSPC;
1709 /* Verify the following entries[n_blocks] won't overflow */
1710 if (n_blocks >= ((size_t)-sizeof(struct wc_memory_superblock) /
1711 sizeof(struct wc_memory_entry)))
1712 return -EFBIG;
1713 offset = offsetof(struct wc_memory_superblock, entries[n_blocks]);
1714 offset = (offset + block_size - 1) & ~(uint64_t)(block_size - 1);
1715 if (offset + n_blocks * block_size <= device_size)
1716 break;
1717 n_blocks--;
1718 }
1719
1720 /* check if the bit field overflows */
1721 e.index = n_blocks;
1722 if (e.index != n_blocks)
1723 return -EFBIG;
1724
1725 if (n_blocks_p)
1726 *n_blocks_p = n_blocks;
1727 if (n_metadata_blocks_p)
1728 *n_metadata_blocks_p = offset >> __ffs(block_size);
1729 return 0;
1730}
1731
1732static int init_memory(struct dm_writecache *wc)
1733{
1734 size_t b;
1735 int r;
1736
1737 r = calculate_memory_size(wc->memory_map_size, wc->block_size, &wc->n_blocks, NULL);
1738 if (r)
1739 return r;
1740
1741 r = writecache_alloc_entries(wc);
1742 if (r)
1743 return r;
1744
1745 for (b = 0; b < ARRAY_SIZE(sb(wc)->padding); b++)
1746 pmem_assign(sb(wc)->padding[b], cpu_to_le64(0));
1747 pmem_assign(sb(wc)->version, cpu_to_le32(MEMORY_SUPERBLOCK_VERSION));
1748 pmem_assign(sb(wc)->block_size, cpu_to_le32(wc->block_size));
1749 pmem_assign(sb(wc)->n_blocks, cpu_to_le64(wc->n_blocks));
1750 pmem_assign(sb(wc)->seq_count, cpu_to_le64(0));
1751
1752 for (b = 0; b < wc->n_blocks; b++)
1753 write_original_sector_seq_count(wc, &wc->entries[b], -1, -1);
1754
1755 writecache_flush_all_metadata(wc);
1756 writecache_commit_flushed(wc);
1757 pmem_assign(sb(wc)->magic, cpu_to_le32(MEMORY_SUPERBLOCK_MAGIC));
1758 writecache_flush_region(wc, &sb(wc)->magic, sizeof sb(wc)->magic);
1759 writecache_commit_flushed(wc);
1760
1761 return 0;
1762}
1763
1764static void writecache_dtr(struct dm_target *ti)
1765{
1766 struct dm_writecache *wc = ti->private;
1767
1768 if (!wc)
1769 return;
1770
1771 if (wc->endio_thread)
1772 kthread_stop(wc->endio_thread);
1773
1774 if (wc->flush_thread)
1775 kthread_stop(wc->flush_thread);
1776
1777 bioset_exit(&wc->bio_set);
1778
1779 mempool_exit(&wc->copy_pool);
1780
1781 if (wc->writeback_wq)
1782 destroy_workqueue(wc->writeback_wq);
1783
1784 if (wc->dev)
1785 dm_put_device(ti, wc->dev);
1786
1787 if (wc->ssd_dev)
1788 dm_put_device(ti, wc->ssd_dev);
1789
1790 if (wc->entries)
1791 vfree(wc->entries);
1792
1793 if (wc->memory_map) {
1794 if (WC_MODE_PMEM(wc))
1795 persistent_memory_release(wc);
1796 else
1797 vfree(wc->memory_map);
1798 }
1799
1800 if (wc->dm_kcopyd)
1801 dm_kcopyd_client_destroy(wc->dm_kcopyd);
1802
1803 if (wc->dm_io)
1804 dm_io_client_destroy(wc->dm_io);
1805
1806 if (wc->dirty_bitmap)
1807 vfree(wc->dirty_bitmap);
1808
1809 kfree(wc);
1810}
1811
1812static int writecache_ctr(struct dm_target *ti, unsigned argc, char **argv)
1813{
1814 struct dm_writecache *wc;
1815 struct dm_arg_set as;
1816 const char *string;
1817 unsigned opt_params;
1818 size_t offset, data_size;
1819 int i, r;
1820 char dummy;
1821 int high_wm_percent = HIGH_WATERMARK;
1822 int low_wm_percent = LOW_WATERMARK;
1823 uint64_t x;
1824 struct wc_memory_superblock s;
1825
1826 static struct dm_arg _args[] = {
1827 {0, 10, "Invalid number of feature args"},
1828 };
1829
1830 as.argc = argc;
1831 as.argv = argv;
1832
1833 wc = kzalloc(sizeof(struct dm_writecache), GFP_KERNEL);
1834 if (!wc) {
1835 ti->error = "Cannot allocate writecache structure";
1836 r = -ENOMEM;
1837 goto bad;
1838 }
1839 ti->private = wc;
1840 wc->ti = ti;
1841
1842 mutex_init(&wc->lock);
1843 writecache_poison_lists(wc);
1844 init_waitqueue_head(&wc->freelist_wait);
1845 timer_setup(&wc->autocommit_timer, writecache_autocommit_timer, 0);
1846
1847 for (i = 0; i < 2; i++) {
1848 atomic_set(&wc->bio_in_progress[i], 0);
1849 init_waitqueue_head(&wc->bio_in_progress_wait[i]);
1850 }
1851
1852 wc->dm_io = dm_io_client_create();
1853 if (IS_ERR(wc->dm_io)) {
1854 r = PTR_ERR(wc->dm_io);
1855 ti->error = "Unable to allocate dm-io client";
1856 wc->dm_io = NULL;
1857 goto bad;
1858 }
1859
1860 wc->writeback_wq = alloc_workqueue("writecache-writeabck", WQ_MEM_RECLAIM, 1);
1861 if (!wc->writeback_wq) {
1862 r = -ENOMEM;
1863 ti->error = "Could not allocate writeback workqueue";
1864 goto bad;
1865 }
1866 INIT_WORK(&wc->writeback_work, writecache_writeback);
1867 INIT_WORK(&wc->flush_work, writecache_flush_work);
1868
1869 raw_spin_lock_init(&wc->endio_list_lock);
1870 INIT_LIST_HEAD(&wc->endio_list);
1871 wc->endio_thread = kthread_create(writecache_endio_thread, wc, "writecache_endio");
1872 if (IS_ERR(wc->endio_thread)) {
1873 r = PTR_ERR(wc->endio_thread);
1874 wc->endio_thread = NULL;
1875 ti->error = "Couldn't spawn endio thread";
1876 goto bad;
1877 }
1878 wake_up_process(wc->endio_thread);
1879
1880 /*
1881 * Parse the mode (pmem or ssd)
1882 */
1883 string = dm_shift_arg(&as);
1884 if (!string)
1885 goto bad_arguments;
1886
1887 if (!strcasecmp(string, "s")) {
1888 wc->pmem_mode = false;
1889 } else if (!strcasecmp(string, "p")) {
1890#ifdef DM_WRITECACHE_HAS_PMEM
1891 wc->pmem_mode = true;
1892 wc->writeback_fua = true;
1893#else
1894 /*
1895 * If the architecture doesn't support persistent memory or
1896 * the kernel doesn't support any DAX drivers, this driver can
1897 * only be used in SSD-only mode.
1898 */
1899 r = -EOPNOTSUPP;
1900 ti->error = "Persistent memory or DAX not supported on this system";
1901 goto bad;
1902#endif
1903 } else {
1904 goto bad_arguments;
1905 }
1906
1907 if (WC_MODE_PMEM(wc)) {
1908 r = bioset_init(&wc->bio_set, BIO_POOL_SIZE,
1909 offsetof(struct writeback_struct, bio),
1910 BIOSET_NEED_BVECS);
1911 if (r) {
1912 ti->error = "Could not allocate bio set";
1913 goto bad;
1914 }
1915 } else {
1916 r = mempool_init_kmalloc_pool(&wc->copy_pool, 1, sizeof(struct copy_struct));
1917 if (r) {
1918 ti->error = "Could not allocate mempool";
1919 goto bad;
1920 }
1921 }
1922
1923 /*
1924 * Parse the origin data device
1925 */
1926 string = dm_shift_arg(&as);
1927 if (!string)
1928 goto bad_arguments;
1929 r = dm_get_device(ti, string, dm_table_get_mode(ti->table), &wc->dev);
1930 if (r) {
1931 ti->error = "Origin data device lookup failed";
1932 goto bad;
1933 }
1934
1935 /*
1936 * Parse cache data device (be it pmem or ssd)
1937 */
1938 string = dm_shift_arg(&as);
1939 if (!string)
1940 goto bad_arguments;
1941
1942 r = dm_get_device(ti, string, dm_table_get_mode(ti->table), &wc->ssd_dev);
1943 if (r) {
1944 ti->error = "Cache data device lookup failed";
1945 goto bad;
1946 }
1947 wc->memory_map_size = i_size_read(wc->ssd_dev->bdev->bd_inode);
1948
1949 if (WC_MODE_PMEM(wc)) {
1950 r = persistent_memory_claim(wc);
1951 if (r) {
1952 ti->error = "Unable to map persistent memory for cache";
1953 goto bad;
1954 }
1955 }
1956
1957 /*
1958 * Parse the cache block size
1959 */
1960 string = dm_shift_arg(&as);
1961 if (!string)
1962 goto bad_arguments;
1963 if (sscanf(string, "%u%c", &wc->block_size, &dummy) != 1 ||
1964 wc->block_size < 512 || wc->block_size > PAGE_SIZE ||
1965 (wc->block_size & (wc->block_size - 1))) {
1966 r = -EINVAL;
1967 ti->error = "Invalid block size";
1968 goto bad;
1969 }
1970 wc->block_size_bits = __ffs(wc->block_size);
1971
1972 wc->max_writeback_jobs = MAX_WRITEBACK_JOBS;
1973 wc->autocommit_blocks = !WC_MODE_PMEM(wc) ? AUTOCOMMIT_BLOCKS_SSD : AUTOCOMMIT_BLOCKS_PMEM;
1974 wc->autocommit_jiffies = msecs_to_jiffies(AUTOCOMMIT_MSEC);
1975
1976 /*
1977 * Parse optional arguments
1978 */
1979 r = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
1980 if (r)
1981 goto bad;
1982
1983 while (opt_params) {
1984 string = dm_shift_arg(&as), opt_params--;
1985 if (!strcasecmp(string, "high_watermark") && opt_params >= 1) {
1986 string = dm_shift_arg(&as), opt_params--;
1987 if (sscanf(string, "%d%c", &high_wm_percent, &dummy) != 1)
1988 goto invalid_optional;
1989 if (high_wm_percent < 0 || high_wm_percent > 100)
1990 goto invalid_optional;
1991 wc->high_wm_percent_set = true;
1992 } else if (!strcasecmp(string, "low_watermark") && opt_params >= 1) {
1993 string = dm_shift_arg(&as), opt_params--;
1994 if (sscanf(string, "%d%c", &low_wm_percent, &dummy) != 1)
1995 goto invalid_optional;
1996 if (low_wm_percent < 0 || low_wm_percent > 100)
1997 goto invalid_optional;
1998 wc->low_wm_percent_set = true;
1999 } else if (!strcasecmp(string, "writeback_jobs") && opt_params >= 1) {
2000 string = dm_shift_arg(&as), opt_params--;
2001 if (sscanf(string, "%u%c", &wc->max_writeback_jobs, &dummy) != 1)
2002 goto invalid_optional;
2003 wc->max_writeback_jobs_set = true;
2004 } else if (!strcasecmp(string, "autocommit_blocks") && opt_params >= 1) {
2005 string = dm_shift_arg(&as), opt_params--;
2006 if (sscanf(string, "%u%c", &wc->autocommit_blocks, &dummy) != 1)
2007 goto invalid_optional;
2008 wc->autocommit_blocks_set = true;
2009 } else if (!strcasecmp(string, "autocommit_time") && opt_params >= 1) {
2010 unsigned autocommit_msecs;
2011 string = dm_shift_arg(&as), opt_params--;
2012 if (sscanf(string, "%u%c", &autocommit_msecs, &dummy) != 1)
2013 goto invalid_optional;
2014 if (autocommit_msecs > 3600000)
2015 goto invalid_optional;
2016 wc->autocommit_jiffies = msecs_to_jiffies(autocommit_msecs);
2017 wc->autocommit_time_set = true;
2018 } else if (!strcasecmp(string, "fua")) {
2019 if (WC_MODE_PMEM(wc)) {
2020 wc->writeback_fua = true;
2021 wc->writeback_fua_set = true;
2022 } else goto invalid_optional;
2023 } else if (!strcasecmp(string, "nofua")) {
2024 if (WC_MODE_PMEM(wc)) {
2025 wc->writeback_fua = false;
2026 wc->writeback_fua_set = true;
2027 } else goto invalid_optional;
2028 } else {
2029invalid_optional:
2030 r = -EINVAL;
2031 ti->error = "Invalid optional argument";
2032 goto bad;
2033 }
2034 }
2035
2036 if (high_wm_percent < low_wm_percent) {
2037 r = -EINVAL;
2038 ti->error = "High watermark must be greater than or equal to low watermark";
2039 goto bad;
2040 }
2041
2042 if (!WC_MODE_PMEM(wc)) {
2043 struct dm_io_region region;
2044 struct dm_io_request req;
2045 size_t n_blocks, n_metadata_blocks;
2046 uint64_t n_bitmap_bits;
2047
2048 bio_list_init(&wc->flush_list);
2049 wc->flush_thread = kthread_create(writecache_flush_thread, wc, "dm_writecache_flush");
2050 if (IS_ERR(wc->flush_thread)) {
2051 r = PTR_ERR(wc->flush_thread);
2052 wc->flush_thread = NULL;
2053 ti->error = "Couldn't spawn endio thread";
2054 goto bad;
2055 }
2056 wake_up_process(wc->flush_thread);
2057
2058 r = calculate_memory_size(wc->memory_map_size, wc->block_size,
2059 &n_blocks, &n_metadata_blocks);
2060 if (r) {
2061 ti->error = "Invalid device size";
2062 goto bad;
2063 }
2064
2065 n_bitmap_bits = (((uint64_t)n_metadata_blocks << wc->block_size_bits) +
2066 BITMAP_GRANULARITY - 1) / BITMAP_GRANULARITY;
2067 /* this is limitation of test_bit functions */
2068 if (n_bitmap_bits > 1U << 31) {
2069 r = -EFBIG;
2070 ti->error = "Invalid device size";
2071 goto bad;
2072 }
2073
2074 wc->memory_map = vmalloc(n_metadata_blocks << wc->block_size_bits);
2075 if (!wc->memory_map) {
2076 r = -ENOMEM;
2077 ti->error = "Unable to allocate memory for metadata";
2078 goto bad;
2079 }
2080
2081 wc->dm_kcopyd = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2082 if (IS_ERR(wc->dm_kcopyd)) {
2083 r = PTR_ERR(wc->dm_kcopyd);
2084 ti->error = "Unable to allocate dm-kcopyd client";
2085 wc->dm_kcopyd = NULL;
2086 goto bad;
2087 }
2088
2089 wc->metadata_sectors = n_metadata_blocks << (wc->block_size_bits - SECTOR_SHIFT);
2090 wc->dirty_bitmap_size = (n_bitmap_bits + BITS_PER_LONG - 1) /
2091 BITS_PER_LONG * sizeof(unsigned long);
2092 wc->dirty_bitmap = vzalloc(wc->dirty_bitmap_size);
2093 if (!wc->dirty_bitmap) {
2094 r = -ENOMEM;
2095 ti->error = "Unable to allocate dirty bitmap";
2096 goto bad;
2097 }
2098
2099 region.bdev = wc->ssd_dev->bdev;
2100 region.sector = 0;
2101 region.count = wc->metadata_sectors;
2102 req.bi_op = REQ_OP_READ;
2103 req.bi_op_flags = REQ_SYNC;
2104 req.mem.type = DM_IO_VMA;
2105 req.mem.ptr.vma = (char *)wc->memory_map;
2106 req.client = wc->dm_io;
2107 req.notify.fn = NULL;
2108
2109 r = dm_io(&req, 1, &region, NULL);
2110 if (r) {
2111 ti->error = "Unable to read metadata";
2112 goto bad;
2113 }
2114 }
2115
2116 r = memcpy_mcsafe(&s, sb(wc), sizeof(struct wc_memory_superblock));
2117 if (r) {
2118 ti->error = "Hardware memory error when reading superblock";
2119 goto bad;
2120 }
2121 if (!le32_to_cpu(s.magic) && !le32_to_cpu(s.version)) {
2122 r = init_memory(wc);
2123 if (r) {
2124 ti->error = "Unable to initialize device";
2125 goto bad;
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 }
2133
2134 if (le32_to_cpu(s.magic) != MEMORY_SUPERBLOCK_MAGIC) {
2135 ti->error = "Invalid magic in the superblock";
2136 r = -EINVAL;
2137 goto bad;
2138 }
2139
2140 if (le32_to_cpu(s.version) != MEMORY_SUPERBLOCK_VERSION) {
2141 ti->error = "Invalid version in the superblock";
2142 r = -EINVAL;
2143 goto bad;
2144 }
2145
2146 if (le32_to_cpu(s.block_size) != wc->block_size) {
2147 ti->error = "Block size does not match superblock";
2148 r = -EINVAL;
2149 goto bad;
2150 }
2151
2152 wc->n_blocks = le64_to_cpu(s.n_blocks);
2153
2154 offset = wc->n_blocks * sizeof(struct wc_memory_entry);
2155 if (offset / sizeof(struct wc_memory_entry) != le64_to_cpu(sb(wc)->n_blocks)) {
2156overflow:
2157 ti->error = "Overflow in size calculation";
2158 r = -EINVAL;
2159 goto bad;
2160 }
2161 offset += sizeof(struct wc_memory_superblock);
2162 if (offset < sizeof(struct wc_memory_superblock))
2163 goto overflow;
2164 offset = (offset + wc->block_size - 1) & ~(size_t)(wc->block_size - 1);
2165 data_size = wc->n_blocks * (size_t)wc->block_size;
2166 if (!offset || (data_size / wc->block_size != wc->n_blocks) ||
2167 (offset + data_size < offset))
2168 goto overflow;
2169 if (offset + data_size > wc->memory_map_size) {
2170 ti->error = "Memory area is too small";
2171 r = -EINVAL;
2172 goto bad;
2173 }
2174
2175 wc->metadata_sectors = offset >> SECTOR_SHIFT;
2176 wc->block_start = (char *)sb(wc) + offset;
2177
2178 x = (uint64_t)wc->n_blocks * (100 - high_wm_percent);
2179 x += 50;
2180 do_div(x, 100);
2181 wc->freelist_high_watermark = x;
2182 x = (uint64_t)wc->n_blocks * (100 - low_wm_percent);
2183 x += 50;
2184 do_div(x, 100);
2185 wc->freelist_low_watermark = x;
2186
2187 r = writecache_alloc_entries(wc);
2188 if (r) {
2189 ti->error = "Cannot allocate memory";
2190 goto bad;
2191 }
2192
2193 ti->num_flush_bios = 1;
2194 ti->flush_supported = true;
2195 ti->num_discard_bios = 1;
2196
2197 if (WC_MODE_PMEM(wc))
2198 persistent_memory_flush_cache(wc->memory_map, wc->memory_map_size);
2199
2200 return 0;
2201
2202bad_arguments:
2203 r = -EINVAL;
2204 ti->error = "Bad arguments";
2205bad:
2206 writecache_dtr(ti);
2207 return r;
2208}
2209
2210static void writecache_status(struct dm_target *ti, status_type_t type,
2211 unsigned status_flags, char *result, unsigned maxlen)
2212{
2213 struct dm_writecache *wc = ti->private;
2214 unsigned extra_args;
2215 unsigned sz = 0;
2216 uint64_t x;
2217
2218 switch (type) {
2219 case STATUSTYPE_INFO:
2220 DMEMIT("%ld %llu %llu %llu", writecache_has_error(wc),
2221 (unsigned long long)wc->n_blocks, (unsigned long long)wc->freelist_size,
2222 (unsigned long long)wc->writeback_size);
2223 break;
2224 case STATUSTYPE_TABLE:
2225 DMEMIT("%c %s %s %u ", WC_MODE_PMEM(wc) ? 'p' : 's',
2226 wc->dev->name, wc->ssd_dev->name, wc->block_size);
2227 extra_args = 0;
2228 if (wc->high_wm_percent_set)
2229 extra_args += 2;
2230 if (wc->low_wm_percent_set)
2231 extra_args += 2;
2232 if (wc->max_writeback_jobs_set)
2233 extra_args += 2;
2234 if (wc->autocommit_blocks_set)
2235 extra_args += 2;
2236 if (wc->autocommit_time_set)
2237 extra_args += 2;
2238 if (wc->writeback_fua_set)
2239 extra_args++;
2240
2241 DMEMIT("%u", extra_args);
2242 if (wc->high_wm_percent_set) {
2243 x = (uint64_t)wc->freelist_high_watermark * 100;
2244 x += wc->n_blocks / 2;
2245 do_div(x, (size_t)wc->n_blocks);
2246 DMEMIT(" high_watermark %u", 100 - (unsigned)x);
2247 }
2248 if (wc->low_wm_percent_set) {
2249 x = (uint64_t)wc->freelist_low_watermark * 100;
2250 x += wc->n_blocks / 2;
2251 do_div(x, (size_t)wc->n_blocks);
2252 DMEMIT(" low_watermark %u", 100 - (unsigned)x);
2253 }
2254 if (wc->max_writeback_jobs_set)
2255 DMEMIT(" writeback_jobs %u", wc->max_writeback_jobs);
2256 if (wc->autocommit_blocks_set)
2257 DMEMIT(" autocommit_blocks %u", wc->autocommit_blocks);
2258 if (wc->autocommit_time_set)
2259 DMEMIT(" autocommit_time %u", jiffies_to_msecs(wc->autocommit_jiffies));
2260 if (wc->writeback_fua_set)
2261 DMEMIT(" %sfua", wc->writeback_fua ? "" : "no");
2262 break;
2263 }
2264}
2265
2266static struct target_type writecache_target = {
2267 .name = "writecache",
2268 .version = {1, 0, 0},
2269 .module = THIS_MODULE,
2270 .ctr = writecache_ctr,
2271 .dtr = writecache_dtr,
2272 .status = writecache_status,
2273 .postsuspend = writecache_suspend,
2274 .resume = writecache_resume,
2275 .message = writecache_message,
2276 .map = writecache_map,
2277 .end_io = writecache_end_io,
2278 .iterate_devices = writecache_iterate_devices,
2279 .io_hints = writecache_io_hints,
2280};
2281
2282static int __init dm_writecache_init(void)
2283{
2284 int r;
2285
2286 r = dm_register_target(&writecache_target);
2287 if (r < 0) {
2288 DMERR("register failed %d", r);
2289 return r;
2290 }
2291
2292 return 0;
2293}
2294
2295static void __exit dm_writecache_exit(void)
2296{
2297 dm_unregister_target(&writecache_target);
2298}
2299
2300module_init(dm_writecache_init);
2301module_exit(dm_writecache_exit);
2302
2303MODULE_DESCRIPTION(DM_NAME " writecache target");
2304MODULE_AUTHOR("Mikulas Patocka <dm-devel@redhat.com>");
2305MODULE_LICENSE("GPL");
Linux 6.x block layer and io_uring tree(s)