Merge tag 'nfs-for-5.20-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs
[linux-2.6-block.git] / drivers / md / dm-writecache.c
... / ...
CommitLineData
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#include <linux/delay.h>
19#include "dm-io-tracker.h"
20
21#define DM_MSG_PREFIX "writecache"
22
23#define HIGH_WATERMARK 50
24#define LOW_WATERMARK 45
25#define MAX_WRITEBACK_JOBS min(0x10000000 / PAGE_SIZE, totalram_pages() / 16)
26#define ENDIO_LATENCY 16
27#define WRITEBACK_LATENCY 64
28#define AUTOCOMMIT_BLOCKS_SSD 65536
29#define AUTOCOMMIT_BLOCKS_PMEM 64
30#define AUTOCOMMIT_MSEC 1000
31#define MAX_AGE_DIV 16
32#define MAX_AGE_UNSPECIFIED -1UL
33#define PAUSE_WRITEBACK (HZ * 3)
34
35#define BITMAP_GRANULARITY 65536
36#if BITMAP_GRANULARITY < PAGE_SIZE
37#undef BITMAP_GRANULARITY
38#define BITMAP_GRANULARITY PAGE_SIZE
39#endif
40
41#if IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API) && IS_ENABLED(CONFIG_FS_DAX)
42#define DM_WRITECACHE_HAS_PMEM
43#endif
44
45#ifdef DM_WRITECACHE_HAS_PMEM
46#define pmem_assign(dest, src) \
47do { \
48 typeof(dest) uniq = (src); \
49 memcpy_flushcache(&(dest), &uniq, sizeof(dest)); \
50} while (0)
51#else
52#define pmem_assign(dest, src) ((dest) = (src))
53#endif
54
55#if IS_ENABLED(CONFIG_ARCH_HAS_COPY_MC) && defined(DM_WRITECACHE_HAS_PMEM)
56#define DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
57#endif
58
59#define MEMORY_SUPERBLOCK_MAGIC 0x23489321
60#define MEMORY_SUPERBLOCK_VERSION 1
61
62struct wc_memory_entry {
63 __le64 original_sector;
64 __le64 seq_count;
65};
66
67struct wc_memory_superblock {
68 union {
69 struct {
70 __le32 magic;
71 __le32 version;
72 __le32 block_size;
73 __le32 pad;
74 __le64 n_blocks;
75 __le64 seq_count;
76 };
77 __le64 padding[8];
78 };
79 struct wc_memory_entry entries[];
80};
81
82struct wc_entry {
83 struct rb_node rb_node;
84 struct list_head lru;
85 unsigned short wc_list_contiguous;
86 bool write_in_progress
87#if BITS_PER_LONG == 64
88 :1
89#endif
90 ;
91 unsigned long index
92#if BITS_PER_LONG == 64
93 :47
94#endif
95 ;
96 unsigned long age;
97#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
98 uint64_t original_sector;
99 uint64_t seq_count;
100#endif
101};
102
103#ifdef DM_WRITECACHE_HAS_PMEM
104#define WC_MODE_PMEM(wc) ((wc)->pmem_mode)
105#define WC_MODE_FUA(wc) ((wc)->writeback_fua)
106#else
107#define WC_MODE_PMEM(wc) false
108#define WC_MODE_FUA(wc) false
109#endif
110#define WC_MODE_SORT_FREELIST(wc) (!WC_MODE_PMEM(wc))
111
112struct dm_writecache {
113 struct mutex lock;
114 struct list_head lru;
115 union {
116 struct list_head freelist;
117 struct {
118 struct rb_root freetree;
119 struct wc_entry *current_free;
120 };
121 };
122 struct rb_root tree;
123
124 size_t freelist_size;
125 size_t writeback_size;
126 size_t freelist_high_watermark;
127 size_t freelist_low_watermark;
128 unsigned long max_age;
129 unsigned long pause;
130
131 unsigned uncommitted_blocks;
132 unsigned autocommit_blocks;
133 unsigned max_writeback_jobs;
134
135 int error;
136
137 unsigned long autocommit_jiffies;
138 struct timer_list autocommit_timer;
139 struct wait_queue_head freelist_wait;
140
141 struct timer_list max_age_timer;
142
143 atomic_t bio_in_progress[2];
144 struct wait_queue_head bio_in_progress_wait[2];
145
146 struct dm_target *ti;
147 struct dm_dev *dev;
148 struct dm_dev *ssd_dev;
149 sector_t start_sector;
150 void *memory_map;
151 uint64_t memory_map_size;
152 size_t metadata_sectors;
153 size_t n_blocks;
154 uint64_t seq_count;
155 sector_t data_device_sectors;
156 void *block_start;
157 struct wc_entry *entries;
158 unsigned block_size;
159 unsigned char block_size_bits;
160
161 bool pmem_mode:1;
162 bool writeback_fua:1;
163
164 bool overwrote_committed:1;
165 bool memory_vmapped:1;
166
167 bool start_sector_set:1;
168 bool high_wm_percent_set:1;
169 bool low_wm_percent_set:1;
170 bool max_writeback_jobs_set:1;
171 bool autocommit_blocks_set:1;
172 bool autocommit_time_set:1;
173 bool max_age_set:1;
174 bool writeback_fua_set:1;
175 bool flush_on_suspend:1;
176 bool cleaner:1;
177 bool cleaner_set:1;
178 bool metadata_only:1;
179 bool pause_set:1;
180
181 unsigned high_wm_percent_value;
182 unsigned low_wm_percent_value;
183 unsigned autocommit_time_value;
184 unsigned max_age_value;
185 unsigned pause_value;
186
187 unsigned writeback_all;
188 struct workqueue_struct *writeback_wq;
189 struct work_struct writeback_work;
190 struct work_struct flush_work;
191
192 struct dm_io_tracker iot;
193
194 struct dm_io_client *dm_io;
195
196 raw_spinlock_t endio_list_lock;
197 struct list_head endio_list;
198 struct task_struct *endio_thread;
199
200 struct task_struct *flush_thread;
201 struct bio_list flush_list;
202
203 struct dm_kcopyd_client *dm_kcopyd;
204 unsigned long *dirty_bitmap;
205 unsigned dirty_bitmap_size;
206
207 struct bio_set bio_set;
208 mempool_t copy_pool;
209
210 struct {
211 unsigned long long reads;
212 unsigned long long read_hits;
213 unsigned long long writes;
214 unsigned long long write_hits_uncommitted;
215 unsigned long long write_hits_committed;
216 unsigned long long writes_around;
217 unsigned long long writes_allocate;
218 unsigned long long writes_blocked_on_freelist;
219 unsigned long long flushes;
220 unsigned long long discards;
221 } stats;
222};
223
224#define WB_LIST_INLINE 16
225
226struct writeback_struct {
227 struct list_head endio_entry;
228 struct dm_writecache *wc;
229 struct wc_entry **wc_list;
230 unsigned wc_list_n;
231 struct wc_entry *wc_list_inline[WB_LIST_INLINE];
232 struct bio bio;
233};
234
235struct copy_struct {
236 struct list_head endio_entry;
237 struct dm_writecache *wc;
238 struct wc_entry *e;
239 unsigned n_entries;
240 int error;
241};
242
243DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(dm_writecache_throttle,
244 "A percentage of time allocated for data copying");
245
246static void wc_lock(struct dm_writecache *wc)
247{
248 mutex_lock(&wc->lock);
249}
250
251static void wc_unlock(struct dm_writecache *wc)
252{
253 mutex_unlock(&wc->lock);
254}
255
256#ifdef DM_WRITECACHE_HAS_PMEM
257static int persistent_memory_claim(struct dm_writecache *wc)
258{
259 int r;
260 loff_t s;
261 long p, da;
262 pfn_t pfn;
263 int id;
264 struct page **pages;
265 sector_t offset;
266
267 wc->memory_vmapped = false;
268
269 s = wc->memory_map_size;
270 p = s >> PAGE_SHIFT;
271 if (!p) {
272 r = -EINVAL;
273 goto err1;
274 }
275 if (p != s >> PAGE_SHIFT) {
276 r = -EOVERFLOW;
277 goto err1;
278 }
279
280 offset = get_start_sect(wc->ssd_dev->bdev);
281 if (offset & (PAGE_SIZE / 512 - 1)) {
282 r = -EINVAL;
283 goto err1;
284 }
285 offset >>= PAGE_SHIFT - 9;
286
287 id = dax_read_lock();
288
289 da = dax_direct_access(wc->ssd_dev->dax_dev, offset, p, DAX_ACCESS,
290 &wc->memory_map, &pfn);
291 if (da < 0) {
292 wc->memory_map = NULL;
293 r = da;
294 goto err2;
295 }
296 if (!pfn_t_has_page(pfn)) {
297 wc->memory_map = NULL;
298 r = -EOPNOTSUPP;
299 goto err2;
300 }
301 if (da != p) {
302 long i;
303 wc->memory_map = NULL;
304 pages = kvmalloc_array(p, sizeof(struct page *), GFP_KERNEL);
305 if (!pages) {
306 r = -ENOMEM;
307 goto err2;
308 }
309 i = 0;
310 do {
311 long daa;
312 daa = dax_direct_access(wc->ssd_dev->dax_dev, offset + i,
313 p - i, DAX_ACCESS, NULL, &pfn);
314 if (daa <= 0) {
315 r = daa ? daa : -EINVAL;
316 goto err3;
317 }
318 if (!pfn_t_has_page(pfn)) {
319 r = -EOPNOTSUPP;
320 goto err3;
321 }
322 while (daa-- && i < p) {
323 pages[i++] = pfn_t_to_page(pfn);
324 pfn.val++;
325 if (!(i & 15))
326 cond_resched();
327 }
328 } while (i < p);
329 wc->memory_map = vmap(pages, p, VM_MAP, PAGE_KERNEL);
330 if (!wc->memory_map) {
331 r = -ENOMEM;
332 goto err3;
333 }
334 kvfree(pages);
335 wc->memory_vmapped = true;
336 }
337
338 dax_read_unlock(id);
339
340 wc->memory_map += (size_t)wc->start_sector << SECTOR_SHIFT;
341 wc->memory_map_size -= (size_t)wc->start_sector << SECTOR_SHIFT;
342
343 return 0;
344err3:
345 kvfree(pages);
346err2:
347 dax_read_unlock(id);
348err1:
349 return r;
350}
351#else
352static int persistent_memory_claim(struct dm_writecache *wc)
353{
354 return -EOPNOTSUPP;
355}
356#endif
357
358static void persistent_memory_release(struct dm_writecache *wc)
359{
360 if (wc->memory_vmapped)
361 vunmap(wc->memory_map - ((size_t)wc->start_sector << SECTOR_SHIFT));
362}
363
364static struct page *persistent_memory_page(void *addr)
365{
366 if (is_vmalloc_addr(addr))
367 return vmalloc_to_page(addr);
368 else
369 return virt_to_page(addr);
370}
371
372static unsigned persistent_memory_page_offset(void *addr)
373{
374 return (unsigned long)addr & (PAGE_SIZE - 1);
375}
376
377static void persistent_memory_flush_cache(void *ptr, size_t size)
378{
379 if (is_vmalloc_addr(ptr))
380 flush_kernel_vmap_range(ptr, size);
381}
382
383static void persistent_memory_invalidate_cache(void *ptr, size_t size)
384{
385 if (is_vmalloc_addr(ptr))
386 invalidate_kernel_vmap_range(ptr, size);
387}
388
389static struct wc_memory_superblock *sb(struct dm_writecache *wc)
390{
391 return wc->memory_map;
392}
393
394static struct wc_memory_entry *memory_entry(struct dm_writecache *wc, struct wc_entry *e)
395{
396 return &sb(wc)->entries[e->index];
397}
398
399static void *memory_data(struct dm_writecache *wc, struct wc_entry *e)
400{
401 return (char *)wc->block_start + (e->index << wc->block_size_bits);
402}
403
404static sector_t cache_sector(struct dm_writecache *wc, struct wc_entry *e)
405{
406 return wc->start_sector + wc->metadata_sectors +
407 ((sector_t)e->index << (wc->block_size_bits - SECTOR_SHIFT));
408}
409
410static uint64_t read_original_sector(struct dm_writecache *wc, struct wc_entry *e)
411{
412#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
413 return e->original_sector;
414#else
415 return le64_to_cpu(memory_entry(wc, e)->original_sector);
416#endif
417}
418
419static uint64_t read_seq_count(struct dm_writecache *wc, struct wc_entry *e)
420{
421#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
422 return e->seq_count;
423#else
424 return le64_to_cpu(memory_entry(wc, e)->seq_count);
425#endif
426}
427
428static void clear_seq_count(struct dm_writecache *wc, struct wc_entry *e)
429{
430#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
431 e->seq_count = -1;
432#endif
433 pmem_assign(memory_entry(wc, e)->seq_count, cpu_to_le64(-1));
434}
435
436static void write_original_sector_seq_count(struct dm_writecache *wc, struct wc_entry *e,
437 uint64_t original_sector, uint64_t seq_count)
438{
439 struct wc_memory_entry me;
440#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
441 e->original_sector = original_sector;
442 e->seq_count = seq_count;
443#endif
444 me.original_sector = cpu_to_le64(original_sector);
445 me.seq_count = cpu_to_le64(seq_count);
446 pmem_assign(*memory_entry(wc, e), me);
447}
448
449#define writecache_error(wc, err, msg, arg...) \
450do { \
451 if (!cmpxchg(&(wc)->error, 0, err)) \
452 DMERR(msg, ##arg); \
453 wake_up(&(wc)->freelist_wait); \
454} while (0)
455
456#define writecache_has_error(wc) (unlikely(READ_ONCE((wc)->error)))
457
458static void writecache_flush_all_metadata(struct dm_writecache *wc)
459{
460 if (!WC_MODE_PMEM(wc))
461 memset(wc->dirty_bitmap, -1, wc->dirty_bitmap_size);
462}
463
464static void writecache_flush_region(struct dm_writecache *wc, void *ptr, size_t size)
465{
466 if (!WC_MODE_PMEM(wc))
467 __set_bit(((char *)ptr - (char *)wc->memory_map) / BITMAP_GRANULARITY,
468 wc->dirty_bitmap);
469}
470
471static void writecache_disk_flush(struct dm_writecache *wc, struct dm_dev *dev);
472
473struct io_notify {
474 struct dm_writecache *wc;
475 struct completion c;
476 atomic_t count;
477};
478
479static void writecache_notify_io(unsigned long error, void *context)
480{
481 struct io_notify *endio = context;
482
483 if (unlikely(error != 0))
484 writecache_error(endio->wc, -EIO, "error writing metadata");
485 BUG_ON(atomic_read(&endio->count) <= 0);
486 if (atomic_dec_and_test(&endio->count))
487 complete(&endio->c);
488}
489
490static void writecache_wait_for_ios(struct dm_writecache *wc, int direction)
491{
492 wait_event(wc->bio_in_progress_wait[direction],
493 !atomic_read(&wc->bio_in_progress[direction]));
494}
495
496static void ssd_commit_flushed(struct dm_writecache *wc, bool wait_for_ios)
497{
498 struct dm_io_region region;
499 struct dm_io_request req;
500 struct io_notify endio = {
501 wc,
502 COMPLETION_INITIALIZER_ONSTACK(endio.c),
503 ATOMIC_INIT(1),
504 };
505 unsigned bitmap_bits = wc->dirty_bitmap_size * 8;
506 unsigned i = 0;
507
508 while (1) {
509 unsigned j;
510 i = find_next_bit(wc->dirty_bitmap, bitmap_bits, i);
511 if (unlikely(i == bitmap_bits))
512 break;
513 j = find_next_zero_bit(wc->dirty_bitmap, bitmap_bits, i);
514
515 region.bdev = wc->ssd_dev->bdev;
516 region.sector = (sector_t)i * (BITMAP_GRANULARITY >> SECTOR_SHIFT);
517 region.count = (sector_t)(j - i) * (BITMAP_GRANULARITY >> SECTOR_SHIFT);
518
519 if (unlikely(region.sector >= wc->metadata_sectors))
520 break;
521 if (unlikely(region.sector + region.count > wc->metadata_sectors))
522 region.count = wc->metadata_sectors - region.sector;
523
524 region.sector += wc->start_sector;
525 atomic_inc(&endio.count);
526 req.bi_opf = REQ_OP_WRITE | REQ_SYNC;
527 req.mem.type = DM_IO_VMA;
528 req.mem.ptr.vma = (char *)wc->memory_map + (size_t)i * BITMAP_GRANULARITY;
529 req.client = wc->dm_io;
530 req.notify.fn = writecache_notify_io;
531 req.notify.context = &endio;
532
533 /* writing via async dm-io (implied by notify.fn above) won't return an error */
534 (void) dm_io(&req, 1, &region, NULL);
535 i = j;
536 }
537
538 writecache_notify_io(0, &endio);
539 wait_for_completion_io(&endio.c);
540
541 if (wait_for_ios)
542 writecache_wait_for_ios(wc, WRITE);
543
544 writecache_disk_flush(wc, wc->ssd_dev);
545
546 memset(wc->dirty_bitmap, 0, wc->dirty_bitmap_size);
547}
548
549static void ssd_commit_superblock(struct dm_writecache *wc)
550{
551 int r;
552 struct dm_io_region region;
553 struct dm_io_request req;
554
555 region.bdev = wc->ssd_dev->bdev;
556 region.sector = 0;
557 region.count = max(4096U, wc->block_size) >> SECTOR_SHIFT;
558
559 if (unlikely(region.sector + region.count > wc->metadata_sectors))
560 region.count = wc->metadata_sectors - region.sector;
561
562 region.sector += wc->start_sector;
563
564 req.bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_FUA;
565 req.mem.type = DM_IO_VMA;
566 req.mem.ptr.vma = (char *)wc->memory_map;
567 req.client = wc->dm_io;
568 req.notify.fn = NULL;
569 req.notify.context = NULL;
570
571 r = dm_io(&req, 1, &region, NULL);
572 if (unlikely(r))
573 writecache_error(wc, r, "error writing superblock");
574}
575
576static void writecache_commit_flushed(struct dm_writecache *wc, bool wait_for_ios)
577{
578 if (WC_MODE_PMEM(wc))
579 pmem_wmb();
580 else
581 ssd_commit_flushed(wc, wait_for_ios);
582}
583
584static void writecache_disk_flush(struct dm_writecache *wc, struct dm_dev *dev)
585{
586 int r;
587 struct dm_io_region region;
588 struct dm_io_request req;
589
590 region.bdev = dev->bdev;
591 region.sector = 0;
592 region.count = 0;
593 req.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
594 req.mem.type = DM_IO_KMEM;
595 req.mem.ptr.addr = NULL;
596 req.client = wc->dm_io;
597 req.notify.fn = NULL;
598
599 r = dm_io(&req, 1, &region, NULL);
600 if (unlikely(r))
601 writecache_error(wc, r, "error flushing metadata: %d", r);
602}
603
604#define WFE_RETURN_FOLLOWING 1
605#define WFE_LOWEST_SEQ 2
606
607static struct wc_entry *writecache_find_entry(struct dm_writecache *wc,
608 uint64_t block, int flags)
609{
610 struct wc_entry *e;
611 struct rb_node *node = wc->tree.rb_node;
612
613 if (unlikely(!node))
614 return NULL;
615
616 while (1) {
617 e = container_of(node, struct wc_entry, rb_node);
618 if (read_original_sector(wc, e) == block)
619 break;
620
621 node = (read_original_sector(wc, e) >= block ?
622 e->rb_node.rb_left : e->rb_node.rb_right);
623 if (unlikely(!node)) {
624 if (!(flags & WFE_RETURN_FOLLOWING))
625 return NULL;
626 if (read_original_sector(wc, e) >= block) {
627 return e;
628 } else {
629 node = rb_next(&e->rb_node);
630 if (unlikely(!node))
631 return NULL;
632 e = container_of(node, struct wc_entry, rb_node);
633 return e;
634 }
635 }
636 }
637
638 while (1) {
639 struct wc_entry *e2;
640 if (flags & WFE_LOWEST_SEQ)
641 node = rb_prev(&e->rb_node);
642 else
643 node = rb_next(&e->rb_node);
644 if (unlikely(!node))
645 return e;
646 e2 = container_of(node, struct wc_entry, rb_node);
647 if (read_original_sector(wc, e2) != block)
648 return e;
649 e = e2;
650 }
651}
652
653static void writecache_insert_entry(struct dm_writecache *wc, struct wc_entry *ins)
654{
655 struct wc_entry *e;
656 struct rb_node **node = &wc->tree.rb_node, *parent = NULL;
657
658 while (*node) {
659 e = container_of(*node, struct wc_entry, rb_node);
660 parent = &e->rb_node;
661 if (read_original_sector(wc, e) > read_original_sector(wc, ins))
662 node = &parent->rb_left;
663 else
664 node = &parent->rb_right;
665 }
666 rb_link_node(&ins->rb_node, parent, node);
667 rb_insert_color(&ins->rb_node, &wc->tree);
668 list_add(&ins->lru, &wc->lru);
669 ins->age = jiffies;
670}
671
672static void writecache_unlink(struct dm_writecache *wc, struct wc_entry *e)
673{
674 list_del(&e->lru);
675 rb_erase(&e->rb_node, &wc->tree);
676}
677
678static void writecache_add_to_freelist(struct dm_writecache *wc, struct wc_entry *e)
679{
680 if (WC_MODE_SORT_FREELIST(wc)) {
681 struct rb_node **node = &wc->freetree.rb_node, *parent = NULL;
682 if (unlikely(!*node))
683 wc->current_free = e;
684 while (*node) {
685 parent = *node;
686 if (&e->rb_node < *node)
687 node = &parent->rb_left;
688 else
689 node = &parent->rb_right;
690 }
691 rb_link_node(&e->rb_node, parent, node);
692 rb_insert_color(&e->rb_node, &wc->freetree);
693 } else {
694 list_add_tail(&e->lru, &wc->freelist);
695 }
696 wc->freelist_size++;
697}
698
699static inline void writecache_verify_watermark(struct dm_writecache *wc)
700{
701 if (unlikely(wc->freelist_size + wc->writeback_size <= wc->freelist_high_watermark))
702 queue_work(wc->writeback_wq, &wc->writeback_work);
703}
704
705static void writecache_max_age_timer(struct timer_list *t)
706{
707 struct dm_writecache *wc = from_timer(wc, t, max_age_timer);
708
709 if (!dm_suspended(wc->ti) && !writecache_has_error(wc)) {
710 queue_work(wc->writeback_wq, &wc->writeback_work);
711 mod_timer(&wc->max_age_timer, jiffies + wc->max_age / MAX_AGE_DIV);
712 }
713}
714
715static struct wc_entry *writecache_pop_from_freelist(struct dm_writecache *wc, sector_t expected_sector)
716{
717 struct wc_entry *e;
718
719 if (WC_MODE_SORT_FREELIST(wc)) {
720 struct rb_node *next;
721 if (unlikely(!wc->current_free))
722 return NULL;
723 e = wc->current_free;
724 if (expected_sector != (sector_t)-1 && unlikely(cache_sector(wc, e) != expected_sector))
725 return NULL;
726 next = rb_next(&e->rb_node);
727 rb_erase(&e->rb_node, &wc->freetree);
728 if (unlikely(!next))
729 next = rb_first(&wc->freetree);
730 wc->current_free = next ? container_of(next, struct wc_entry, rb_node) : NULL;
731 } else {
732 if (unlikely(list_empty(&wc->freelist)))
733 return NULL;
734 e = container_of(wc->freelist.next, struct wc_entry, lru);
735 if (expected_sector != (sector_t)-1 && unlikely(cache_sector(wc, e) != expected_sector))
736 return NULL;
737 list_del(&e->lru);
738 }
739 wc->freelist_size--;
740
741 writecache_verify_watermark(wc);
742
743 return e;
744}
745
746static void writecache_free_entry(struct dm_writecache *wc, struct wc_entry *e)
747{
748 writecache_unlink(wc, e);
749 writecache_add_to_freelist(wc, e);
750 clear_seq_count(wc, e);
751 writecache_flush_region(wc, memory_entry(wc, e), sizeof(struct wc_memory_entry));
752 if (unlikely(waitqueue_active(&wc->freelist_wait)))
753 wake_up(&wc->freelist_wait);
754}
755
756static void writecache_wait_on_freelist(struct dm_writecache *wc)
757{
758 DEFINE_WAIT(wait);
759
760 prepare_to_wait(&wc->freelist_wait, &wait, TASK_UNINTERRUPTIBLE);
761 wc_unlock(wc);
762 io_schedule();
763 finish_wait(&wc->freelist_wait, &wait);
764 wc_lock(wc);
765}
766
767static void writecache_poison_lists(struct dm_writecache *wc)
768{
769 /*
770 * Catch incorrect access to these values while the device is suspended.
771 */
772 memset(&wc->tree, -1, sizeof wc->tree);
773 wc->lru.next = LIST_POISON1;
774 wc->lru.prev = LIST_POISON2;
775 wc->freelist.next = LIST_POISON1;
776 wc->freelist.prev = LIST_POISON2;
777}
778
779static void writecache_flush_entry(struct dm_writecache *wc, struct wc_entry *e)
780{
781 writecache_flush_region(wc, memory_entry(wc, e), sizeof(struct wc_memory_entry));
782 if (WC_MODE_PMEM(wc))
783 writecache_flush_region(wc, memory_data(wc, e), wc->block_size);
784}
785
786static bool writecache_entry_is_committed(struct dm_writecache *wc, struct wc_entry *e)
787{
788 return read_seq_count(wc, e) < wc->seq_count;
789}
790
791static void writecache_flush(struct dm_writecache *wc)
792{
793 struct wc_entry *e, *e2;
794 bool need_flush_after_free;
795
796 wc->uncommitted_blocks = 0;
797 del_timer(&wc->autocommit_timer);
798
799 if (list_empty(&wc->lru))
800 return;
801
802 e = container_of(wc->lru.next, struct wc_entry, lru);
803 if (writecache_entry_is_committed(wc, e)) {
804 if (wc->overwrote_committed) {
805 writecache_wait_for_ios(wc, WRITE);
806 writecache_disk_flush(wc, wc->ssd_dev);
807 wc->overwrote_committed = false;
808 }
809 return;
810 }
811 while (1) {
812 writecache_flush_entry(wc, e);
813 if (unlikely(e->lru.next == &wc->lru))
814 break;
815 e2 = container_of(e->lru.next, struct wc_entry, lru);
816 if (writecache_entry_is_committed(wc, e2))
817 break;
818 e = e2;
819 cond_resched();
820 }
821 writecache_commit_flushed(wc, true);
822
823 wc->seq_count++;
824 pmem_assign(sb(wc)->seq_count, cpu_to_le64(wc->seq_count));
825 if (WC_MODE_PMEM(wc))
826 writecache_commit_flushed(wc, false);
827 else
828 ssd_commit_superblock(wc);
829
830 wc->overwrote_committed = false;
831
832 need_flush_after_free = false;
833 while (1) {
834 /* Free another committed entry with lower seq-count */
835 struct rb_node *rb_node = rb_prev(&e->rb_node);
836
837 if (rb_node) {
838 e2 = container_of(rb_node, struct wc_entry, rb_node);
839 if (read_original_sector(wc, e2) == read_original_sector(wc, e) &&
840 likely(!e2->write_in_progress)) {
841 writecache_free_entry(wc, e2);
842 need_flush_after_free = true;
843 }
844 }
845 if (unlikely(e->lru.prev == &wc->lru))
846 break;
847 e = container_of(e->lru.prev, struct wc_entry, lru);
848 cond_resched();
849 }
850
851 if (need_flush_after_free)
852 writecache_commit_flushed(wc, false);
853}
854
855static void writecache_flush_work(struct work_struct *work)
856{
857 struct dm_writecache *wc = container_of(work, struct dm_writecache, flush_work);
858
859 wc_lock(wc);
860 writecache_flush(wc);
861 wc_unlock(wc);
862}
863
864static void writecache_autocommit_timer(struct timer_list *t)
865{
866 struct dm_writecache *wc = from_timer(wc, t, autocommit_timer);
867 if (!writecache_has_error(wc))
868 queue_work(wc->writeback_wq, &wc->flush_work);
869}
870
871static void writecache_schedule_autocommit(struct dm_writecache *wc)
872{
873 if (!timer_pending(&wc->autocommit_timer))
874 mod_timer(&wc->autocommit_timer, jiffies + wc->autocommit_jiffies);
875}
876
877static void writecache_discard(struct dm_writecache *wc, sector_t start, sector_t end)
878{
879 struct wc_entry *e;
880 bool discarded_something = false;
881
882 e = writecache_find_entry(wc, start, WFE_RETURN_FOLLOWING | WFE_LOWEST_SEQ);
883 if (unlikely(!e))
884 return;
885
886 while (read_original_sector(wc, e) < end) {
887 struct rb_node *node = rb_next(&e->rb_node);
888
889 if (likely(!e->write_in_progress)) {
890 if (!discarded_something) {
891 if (!WC_MODE_PMEM(wc)) {
892 writecache_wait_for_ios(wc, READ);
893 writecache_wait_for_ios(wc, WRITE);
894 }
895 discarded_something = true;
896 }
897 if (!writecache_entry_is_committed(wc, e))
898 wc->uncommitted_blocks--;
899 writecache_free_entry(wc, e);
900 }
901
902 if (unlikely(!node))
903 break;
904
905 e = container_of(node, struct wc_entry, rb_node);
906 }
907
908 if (discarded_something)
909 writecache_commit_flushed(wc, false);
910}
911
912static bool writecache_wait_for_writeback(struct dm_writecache *wc)
913{
914 if (wc->writeback_size) {
915 writecache_wait_on_freelist(wc);
916 return true;
917 }
918 return false;
919}
920
921static void writecache_suspend(struct dm_target *ti)
922{
923 struct dm_writecache *wc = ti->private;
924 bool flush_on_suspend;
925
926 del_timer_sync(&wc->autocommit_timer);
927 del_timer_sync(&wc->max_age_timer);
928
929 wc_lock(wc);
930 writecache_flush(wc);
931 flush_on_suspend = wc->flush_on_suspend;
932 if (flush_on_suspend) {
933 wc->flush_on_suspend = false;
934 wc->writeback_all++;
935 queue_work(wc->writeback_wq, &wc->writeback_work);
936 }
937 wc_unlock(wc);
938
939 drain_workqueue(wc->writeback_wq);
940
941 wc_lock(wc);
942 if (flush_on_suspend)
943 wc->writeback_all--;
944 while (writecache_wait_for_writeback(wc));
945
946 if (WC_MODE_PMEM(wc))
947 persistent_memory_flush_cache(wc->memory_map, wc->memory_map_size);
948
949 writecache_poison_lists(wc);
950
951 wc_unlock(wc);
952}
953
954static int writecache_alloc_entries(struct dm_writecache *wc)
955{
956 size_t b;
957
958 if (wc->entries)
959 return 0;
960 wc->entries = vmalloc(array_size(sizeof(struct wc_entry), wc->n_blocks));
961 if (!wc->entries)
962 return -ENOMEM;
963 for (b = 0; b < wc->n_blocks; b++) {
964 struct wc_entry *e = &wc->entries[b];
965 e->index = b;
966 e->write_in_progress = false;
967 cond_resched();
968 }
969
970 return 0;
971}
972
973static int writecache_read_metadata(struct dm_writecache *wc, sector_t n_sectors)
974{
975 struct dm_io_region region;
976 struct dm_io_request req;
977
978 region.bdev = wc->ssd_dev->bdev;
979 region.sector = wc->start_sector;
980 region.count = n_sectors;
981 req.bi_opf = REQ_OP_READ | REQ_SYNC;
982 req.mem.type = DM_IO_VMA;
983 req.mem.ptr.vma = (char *)wc->memory_map;
984 req.client = wc->dm_io;
985 req.notify.fn = NULL;
986
987 return dm_io(&req, 1, &region, NULL);
988}
989
990static void writecache_resume(struct dm_target *ti)
991{
992 struct dm_writecache *wc = ti->private;
993 size_t b;
994 bool need_flush = false;
995 __le64 sb_seq_count;
996 int r;
997
998 wc_lock(wc);
999
1000 wc->data_device_sectors = bdev_nr_sectors(wc->dev->bdev);
1001
1002 if (WC_MODE_PMEM(wc)) {
1003 persistent_memory_invalidate_cache(wc->memory_map, wc->memory_map_size);
1004 } else {
1005 r = writecache_read_metadata(wc, wc->metadata_sectors);
1006 if (r) {
1007 size_t sb_entries_offset;
1008 writecache_error(wc, r, "unable to read metadata: %d", r);
1009 sb_entries_offset = offsetof(struct wc_memory_superblock, entries);
1010 memset((char *)wc->memory_map + sb_entries_offset, -1,
1011 (wc->metadata_sectors << SECTOR_SHIFT) - sb_entries_offset);
1012 }
1013 }
1014
1015 wc->tree = RB_ROOT;
1016 INIT_LIST_HEAD(&wc->lru);
1017 if (WC_MODE_SORT_FREELIST(wc)) {
1018 wc->freetree = RB_ROOT;
1019 wc->current_free = NULL;
1020 } else {
1021 INIT_LIST_HEAD(&wc->freelist);
1022 }
1023 wc->freelist_size = 0;
1024
1025 r = copy_mc_to_kernel(&sb_seq_count, &sb(wc)->seq_count,
1026 sizeof(uint64_t));
1027 if (r) {
1028 writecache_error(wc, r, "hardware memory error when reading superblock: %d", r);
1029 sb_seq_count = cpu_to_le64(0);
1030 }
1031 wc->seq_count = le64_to_cpu(sb_seq_count);
1032
1033#ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
1034 for (b = 0; b < wc->n_blocks; b++) {
1035 struct wc_entry *e = &wc->entries[b];
1036 struct wc_memory_entry wme;
1037 if (writecache_has_error(wc)) {
1038 e->original_sector = -1;
1039 e->seq_count = -1;
1040 continue;
1041 }
1042 r = copy_mc_to_kernel(&wme, memory_entry(wc, e),
1043 sizeof(struct wc_memory_entry));
1044 if (r) {
1045 writecache_error(wc, r, "hardware memory error when reading metadata entry %lu: %d",
1046 (unsigned long)b, r);
1047 e->original_sector = -1;
1048 e->seq_count = -1;
1049 } else {
1050 e->original_sector = le64_to_cpu(wme.original_sector);
1051 e->seq_count = le64_to_cpu(wme.seq_count);
1052 }
1053 cond_resched();
1054 }
1055#endif
1056 for (b = 0; b < wc->n_blocks; b++) {
1057 struct wc_entry *e = &wc->entries[b];
1058 if (!writecache_entry_is_committed(wc, e)) {
1059 if (read_seq_count(wc, e) != -1) {
1060erase_this:
1061 clear_seq_count(wc, e);
1062 need_flush = true;
1063 }
1064 writecache_add_to_freelist(wc, e);
1065 } else {
1066 struct wc_entry *old;
1067
1068 old = writecache_find_entry(wc, read_original_sector(wc, e), 0);
1069 if (!old) {
1070 writecache_insert_entry(wc, e);
1071 } else {
1072 if (read_seq_count(wc, old) == read_seq_count(wc, e)) {
1073 writecache_error(wc, -EINVAL,
1074 "two identical entries, position %llu, sector %llu, sequence %llu",
1075 (unsigned long long)b, (unsigned long long)read_original_sector(wc, e),
1076 (unsigned long long)read_seq_count(wc, e));
1077 }
1078 if (read_seq_count(wc, old) > read_seq_count(wc, e)) {
1079 goto erase_this;
1080 } else {
1081 writecache_free_entry(wc, old);
1082 writecache_insert_entry(wc, e);
1083 need_flush = true;
1084 }
1085 }
1086 }
1087 cond_resched();
1088 }
1089
1090 if (need_flush) {
1091 writecache_flush_all_metadata(wc);
1092 writecache_commit_flushed(wc, false);
1093 }
1094
1095 writecache_verify_watermark(wc);
1096
1097 if (wc->max_age != MAX_AGE_UNSPECIFIED)
1098 mod_timer(&wc->max_age_timer, jiffies + wc->max_age / MAX_AGE_DIV);
1099
1100 wc_unlock(wc);
1101}
1102
1103static int process_flush_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
1104{
1105 if (argc != 1)
1106 return -EINVAL;
1107
1108 wc_lock(wc);
1109 if (dm_suspended(wc->ti)) {
1110 wc_unlock(wc);
1111 return -EBUSY;
1112 }
1113 if (writecache_has_error(wc)) {
1114 wc_unlock(wc);
1115 return -EIO;
1116 }
1117
1118 writecache_flush(wc);
1119 wc->writeback_all++;
1120 queue_work(wc->writeback_wq, &wc->writeback_work);
1121 wc_unlock(wc);
1122
1123 flush_workqueue(wc->writeback_wq);
1124
1125 wc_lock(wc);
1126 wc->writeback_all--;
1127 if (writecache_has_error(wc)) {
1128 wc_unlock(wc);
1129 return -EIO;
1130 }
1131 wc_unlock(wc);
1132
1133 return 0;
1134}
1135
1136static int process_flush_on_suspend_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
1137{
1138 if (argc != 1)
1139 return -EINVAL;
1140
1141 wc_lock(wc);
1142 wc->flush_on_suspend = true;
1143 wc_unlock(wc);
1144
1145 return 0;
1146}
1147
1148static void activate_cleaner(struct dm_writecache *wc)
1149{
1150 wc->flush_on_suspend = true;
1151 wc->cleaner = true;
1152 wc->freelist_high_watermark = wc->n_blocks;
1153 wc->freelist_low_watermark = wc->n_blocks;
1154}
1155
1156static int process_cleaner_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
1157{
1158 if (argc != 1)
1159 return -EINVAL;
1160
1161 wc_lock(wc);
1162 activate_cleaner(wc);
1163 if (!dm_suspended(wc->ti))
1164 writecache_verify_watermark(wc);
1165 wc_unlock(wc);
1166
1167 return 0;
1168}
1169
1170static int process_clear_stats_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
1171{
1172 if (argc != 1)
1173 return -EINVAL;
1174
1175 wc_lock(wc);
1176 memset(&wc->stats, 0, sizeof wc->stats);
1177 wc_unlock(wc);
1178
1179 return 0;
1180}
1181
1182static int writecache_message(struct dm_target *ti, unsigned argc, char **argv,
1183 char *result, unsigned maxlen)
1184{
1185 int r = -EINVAL;
1186 struct dm_writecache *wc = ti->private;
1187
1188 if (!strcasecmp(argv[0], "flush"))
1189 r = process_flush_mesg(argc, argv, wc);
1190 else if (!strcasecmp(argv[0], "flush_on_suspend"))
1191 r = process_flush_on_suspend_mesg(argc, argv, wc);
1192 else if (!strcasecmp(argv[0], "cleaner"))
1193 r = process_cleaner_mesg(argc, argv, wc);
1194 else if (!strcasecmp(argv[0], "clear_stats"))
1195 r = process_clear_stats_mesg(argc, argv, wc);
1196 else
1197 DMERR("unrecognised message received: %s", argv[0]);
1198
1199 return r;
1200}
1201
1202static void memcpy_flushcache_optimized(void *dest, void *source, size_t size)
1203{
1204 /*
1205 * clflushopt performs better with block size 1024, 2048, 4096
1206 * non-temporal stores perform better with block size 512
1207 *
1208 * block size 512 1024 2048 4096
1209 * movnti 496 MB/s 642 MB/s 725 MB/s 744 MB/s
1210 * clflushopt 373 MB/s 688 MB/s 1.1 GB/s 1.2 GB/s
1211 *
1212 * We see that movnti performs better for 512-byte blocks, and
1213 * clflushopt performs better for 1024-byte and larger blocks. So, we
1214 * prefer clflushopt for sizes >= 768.
1215 *
1216 * NOTE: this happens to be the case now (with dm-writecache's single
1217 * threaded model) but re-evaluate this once memcpy_flushcache() is
1218 * enabled to use movdir64b which might invalidate this performance
1219 * advantage seen with cache-allocating-writes plus flushing.
1220 */
1221#ifdef CONFIG_X86
1222 if (static_cpu_has(X86_FEATURE_CLFLUSHOPT) &&
1223 likely(boot_cpu_data.x86_clflush_size == 64) &&
1224 likely(size >= 768)) {
1225 do {
1226 memcpy((void *)dest, (void *)source, 64);
1227 clflushopt((void *)dest);
1228 dest += 64;
1229 source += 64;
1230 size -= 64;
1231 } while (size >= 64);
1232 return;
1233 }
1234#endif
1235 memcpy_flushcache(dest, source, size);
1236}
1237
1238static void bio_copy_block(struct dm_writecache *wc, struct bio *bio, void *data)
1239{
1240 void *buf;
1241 unsigned size;
1242 int rw = bio_data_dir(bio);
1243 unsigned remaining_size = wc->block_size;
1244
1245 do {
1246 struct bio_vec bv = bio_iter_iovec(bio, bio->bi_iter);
1247 buf = bvec_kmap_local(&bv);
1248 size = bv.bv_len;
1249 if (unlikely(size > remaining_size))
1250 size = remaining_size;
1251
1252 if (rw == READ) {
1253 int r;
1254 r = copy_mc_to_kernel(buf, data, size);
1255 flush_dcache_page(bio_page(bio));
1256 if (unlikely(r)) {
1257 writecache_error(wc, r, "hardware memory error when reading data: %d", r);
1258 bio->bi_status = BLK_STS_IOERR;
1259 }
1260 } else {
1261 flush_dcache_page(bio_page(bio));
1262 memcpy_flushcache_optimized(data, buf, size);
1263 }
1264
1265 kunmap_local(buf);
1266
1267 data = (char *)data + size;
1268 remaining_size -= size;
1269 bio_advance(bio, size);
1270 } while (unlikely(remaining_size));
1271}
1272
1273static int writecache_flush_thread(void *data)
1274{
1275 struct dm_writecache *wc = data;
1276
1277 while (1) {
1278 struct bio *bio;
1279
1280 wc_lock(wc);
1281 bio = bio_list_pop(&wc->flush_list);
1282 if (!bio) {
1283 set_current_state(TASK_INTERRUPTIBLE);
1284 wc_unlock(wc);
1285
1286 if (unlikely(kthread_should_stop())) {
1287 set_current_state(TASK_RUNNING);
1288 break;
1289 }
1290
1291 schedule();
1292 continue;
1293 }
1294
1295 if (bio_op(bio) == REQ_OP_DISCARD) {
1296 writecache_discard(wc, bio->bi_iter.bi_sector,
1297 bio_end_sector(bio));
1298 wc_unlock(wc);
1299 bio_set_dev(bio, wc->dev->bdev);
1300 submit_bio_noacct(bio);
1301 } else {
1302 writecache_flush(wc);
1303 wc_unlock(wc);
1304 if (writecache_has_error(wc))
1305 bio->bi_status = BLK_STS_IOERR;
1306 bio_endio(bio);
1307 }
1308 }
1309
1310 return 0;
1311}
1312
1313static void writecache_offload_bio(struct dm_writecache *wc, struct bio *bio)
1314{
1315 if (bio_list_empty(&wc->flush_list))
1316 wake_up_process(wc->flush_thread);
1317 bio_list_add(&wc->flush_list, bio);
1318}
1319
1320enum wc_map_op {
1321 WC_MAP_SUBMIT,
1322 WC_MAP_REMAP,
1323 WC_MAP_REMAP_ORIGIN,
1324 WC_MAP_RETURN,
1325 WC_MAP_ERROR,
1326};
1327
1328static void writecache_map_remap_origin(struct dm_writecache *wc, struct bio *bio,
1329 struct wc_entry *e)
1330{
1331 if (e) {
1332 sector_t next_boundary =
1333 read_original_sector(wc, e) - bio->bi_iter.bi_sector;
1334 if (next_boundary < bio->bi_iter.bi_size >> SECTOR_SHIFT)
1335 dm_accept_partial_bio(bio, next_boundary);
1336 }
1337}
1338
1339static enum wc_map_op writecache_map_read(struct dm_writecache *wc, struct bio *bio)
1340{
1341 enum wc_map_op map_op;
1342 struct wc_entry *e;
1343
1344read_next_block:
1345 wc->stats.reads++;
1346 e = writecache_find_entry(wc, bio->bi_iter.bi_sector, WFE_RETURN_FOLLOWING);
1347 if (e && read_original_sector(wc, e) == bio->bi_iter.bi_sector) {
1348 wc->stats.read_hits++;
1349 if (WC_MODE_PMEM(wc)) {
1350 bio_copy_block(wc, bio, memory_data(wc, e));
1351 if (bio->bi_iter.bi_size)
1352 goto read_next_block;
1353 map_op = WC_MAP_SUBMIT;
1354 } else {
1355 dm_accept_partial_bio(bio, wc->block_size >> SECTOR_SHIFT);
1356 bio_set_dev(bio, wc->ssd_dev->bdev);
1357 bio->bi_iter.bi_sector = cache_sector(wc, e);
1358 if (!writecache_entry_is_committed(wc, e))
1359 writecache_wait_for_ios(wc, WRITE);
1360 map_op = WC_MAP_REMAP;
1361 }
1362 } else {
1363 writecache_map_remap_origin(wc, bio, e);
1364 wc->stats.reads += (bio->bi_iter.bi_size - wc->block_size) >> wc->block_size_bits;
1365 map_op = WC_MAP_REMAP_ORIGIN;
1366 }
1367
1368 return map_op;
1369}
1370
1371static void writecache_bio_copy_ssd(struct dm_writecache *wc, struct bio *bio,
1372 struct wc_entry *e, bool search_used)
1373{
1374 unsigned bio_size = wc->block_size;
1375 sector_t start_cache_sec = cache_sector(wc, e);
1376 sector_t current_cache_sec = start_cache_sec + (bio_size >> SECTOR_SHIFT);
1377
1378 while (bio_size < bio->bi_iter.bi_size) {
1379 if (!search_used) {
1380 struct wc_entry *f = writecache_pop_from_freelist(wc, current_cache_sec);
1381 if (!f)
1382 break;
1383 write_original_sector_seq_count(wc, f, bio->bi_iter.bi_sector +
1384 (bio_size >> SECTOR_SHIFT), wc->seq_count);
1385 writecache_insert_entry(wc, f);
1386 wc->uncommitted_blocks++;
1387 } else {
1388 struct wc_entry *f;
1389 struct rb_node *next = rb_next(&e->rb_node);
1390 if (!next)
1391 break;
1392 f = container_of(next, struct wc_entry, rb_node);
1393 if (f != e + 1)
1394 break;
1395 if (read_original_sector(wc, f) !=
1396 read_original_sector(wc, e) + (wc->block_size >> SECTOR_SHIFT))
1397 break;
1398 if (unlikely(f->write_in_progress))
1399 break;
1400 if (writecache_entry_is_committed(wc, f))
1401 wc->overwrote_committed = true;
1402 e = f;
1403 }
1404 bio_size += wc->block_size;
1405 current_cache_sec += wc->block_size >> SECTOR_SHIFT;
1406 }
1407
1408 bio_set_dev(bio, wc->ssd_dev->bdev);
1409 bio->bi_iter.bi_sector = start_cache_sec;
1410 dm_accept_partial_bio(bio, bio_size >> SECTOR_SHIFT);
1411
1412 wc->stats.writes += bio->bi_iter.bi_size >> wc->block_size_bits;
1413 wc->stats.writes_allocate += (bio->bi_iter.bi_size - wc->block_size) >> wc->block_size_bits;
1414
1415 if (unlikely(wc->uncommitted_blocks >= wc->autocommit_blocks)) {
1416 wc->uncommitted_blocks = 0;
1417 queue_work(wc->writeback_wq, &wc->flush_work);
1418 } else {
1419 writecache_schedule_autocommit(wc);
1420 }
1421}
1422
1423static enum wc_map_op writecache_map_write(struct dm_writecache *wc, struct bio *bio)
1424{
1425 struct wc_entry *e;
1426
1427 do {
1428 bool found_entry = false;
1429 bool search_used = false;
1430 if (writecache_has_error(wc)) {
1431 wc->stats.writes += bio->bi_iter.bi_size >> wc->block_size_bits;
1432 return WC_MAP_ERROR;
1433 }
1434 e = writecache_find_entry(wc, bio->bi_iter.bi_sector, 0);
1435 if (e) {
1436 if (!writecache_entry_is_committed(wc, e)) {
1437 wc->stats.write_hits_uncommitted++;
1438 search_used = true;
1439 goto bio_copy;
1440 }
1441 wc->stats.write_hits_committed++;
1442 if (!WC_MODE_PMEM(wc) && !e->write_in_progress) {
1443 wc->overwrote_committed = true;
1444 search_used = true;
1445 goto bio_copy;
1446 }
1447 found_entry = true;
1448 } else {
1449 if (unlikely(wc->cleaner) ||
1450 (wc->metadata_only && !(bio->bi_opf & REQ_META)))
1451 goto direct_write;
1452 }
1453 e = writecache_pop_from_freelist(wc, (sector_t)-1);
1454 if (unlikely(!e)) {
1455 if (!WC_MODE_PMEM(wc) && !found_entry) {
1456direct_write:
1457 e = writecache_find_entry(wc, bio->bi_iter.bi_sector, WFE_RETURN_FOLLOWING);
1458 writecache_map_remap_origin(wc, bio, e);
1459 wc->stats.writes_around += bio->bi_iter.bi_size >> wc->block_size_bits;
1460 wc->stats.writes += bio->bi_iter.bi_size >> wc->block_size_bits;
1461 return WC_MAP_REMAP_ORIGIN;
1462 }
1463 wc->stats.writes_blocked_on_freelist++;
1464 writecache_wait_on_freelist(wc);
1465 continue;
1466 }
1467 write_original_sector_seq_count(wc, e, bio->bi_iter.bi_sector, wc->seq_count);
1468 writecache_insert_entry(wc, e);
1469 wc->uncommitted_blocks++;
1470 wc->stats.writes_allocate++;
1471bio_copy:
1472 if (WC_MODE_PMEM(wc)) {
1473 bio_copy_block(wc, bio, memory_data(wc, e));
1474 wc->stats.writes++;
1475 } else {
1476 writecache_bio_copy_ssd(wc, bio, e, search_used);
1477 return WC_MAP_REMAP;
1478 }
1479 } while (bio->bi_iter.bi_size);
1480
1481 if (unlikely(bio->bi_opf & REQ_FUA || wc->uncommitted_blocks >= wc->autocommit_blocks))
1482 writecache_flush(wc);
1483 else
1484 writecache_schedule_autocommit(wc);
1485
1486 return WC_MAP_SUBMIT;
1487}
1488
1489static enum wc_map_op writecache_map_flush(struct dm_writecache *wc, struct bio *bio)
1490{
1491 if (writecache_has_error(wc))
1492 return WC_MAP_ERROR;
1493
1494 if (WC_MODE_PMEM(wc)) {
1495 wc->stats.flushes++;
1496 writecache_flush(wc);
1497 if (writecache_has_error(wc))
1498 return WC_MAP_ERROR;
1499 else if (unlikely(wc->cleaner) || unlikely(wc->metadata_only))
1500 return WC_MAP_REMAP_ORIGIN;
1501 return WC_MAP_SUBMIT;
1502 }
1503 /* SSD: */
1504 if (dm_bio_get_target_bio_nr(bio))
1505 return WC_MAP_REMAP_ORIGIN;
1506 wc->stats.flushes++;
1507 writecache_offload_bio(wc, bio);
1508 return WC_MAP_RETURN;
1509}
1510
1511static enum wc_map_op writecache_map_discard(struct dm_writecache *wc, struct bio *bio)
1512{
1513 wc->stats.discards += bio->bi_iter.bi_size >> wc->block_size_bits;
1514
1515 if (writecache_has_error(wc))
1516 return WC_MAP_ERROR;
1517
1518 if (WC_MODE_PMEM(wc)) {
1519 writecache_discard(wc, bio->bi_iter.bi_sector, bio_end_sector(bio));
1520 return WC_MAP_REMAP_ORIGIN;
1521 }
1522 /* SSD: */
1523 writecache_offload_bio(wc, bio);
1524 return WC_MAP_RETURN;
1525}
1526
1527static int writecache_map(struct dm_target *ti, struct bio *bio)
1528{
1529 struct dm_writecache *wc = ti->private;
1530 enum wc_map_op map_op;
1531
1532 bio->bi_private = NULL;
1533
1534 wc_lock(wc);
1535
1536 if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
1537 map_op = writecache_map_flush(wc, bio);
1538 goto done;
1539 }
1540
1541 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
1542
1543 if (unlikely((((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) &
1544 (wc->block_size / 512 - 1)) != 0)) {
1545 DMERR("I/O is not aligned, sector %llu, size %u, block size %u",
1546 (unsigned long long)bio->bi_iter.bi_sector,
1547 bio->bi_iter.bi_size, wc->block_size);
1548 map_op = WC_MAP_ERROR;
1549 goto done;
1550 }
1551
1552 if (unlikely(bio_op(bio) == REQ_OP_DISCARD)) {
1553 map_op = writecache_map_discard(wc, bio);
1554 goto done;
1555 }
1556
1557 if (bio_data_dir(bio) == READ)
1558 map_op = writecache_map_read(wc, bio);
1559 else
1560 map_op = writecache_map_write(wc, bio);
1561done:
1562 switch (map_op) {
1563 case WC_MAP_REMAP_ORIGIN:
1564 if (likely(wc->pause != 0)) {
1565 if (bio_op(bio) == REQ_OP_WRITE) {
1566 dm_iot_io_begin(&wc->iot, 1);
1567 bio->bi_private = (void *)2;
1568 }
1569 }
1570 bio_set_dev(bio, wc->dev->bdev);
1571 wc_unlock(wc);
1572 return DM_MAPIO_REMAPPED;
1573
1574 case WC_MAP_REMAP:
1575 /* make sure that writecache_end_io decrements bio_in_progress: */
1576 bio->bi_private = (void *)1;
1577 atomic_inc(&wc->bio_in_progress[bio_data_dir(bio)]);
1578 wc_unlock(wc);
1579 return DM_MAPIO_REMAPPED;
1580
1581 case WC_MAP_SUBMIT:
1582 wc_unlock(wc);
1583 bio_endio(bio);
1584 return DM_MAPIO_SUBMITTED;
1585
1586 case WC_MAP_RETURN:
1587 wc_unlock(wc);
1588 return DM_MAPIO_SUBMITTED;
1589
1590 case WC_MAP_ERROR:
1591 wc_unlock(wc);
1592 bio_io_error(bio);
1593 return DM_MAPIO_SUBMITTED;
1594
1595 default:
1596 BUG();
1597 return -1;
1598 }
1599}
1600
1601static int writecache_end_io(struct dm_target *ti, struct bio *bio, blk_status_t *status)
1602{
1603 struct dm_writecache *wc = ti->private;
1604
1605 if (bio->bi_private == (void *)1) {
1606 int dir = bio_data_dir(bio);
1607 if (atomic_dec_and_test(&wc->bio_in_progress[dir]))
1608 if (unlikely(waitqueue_active(&wc->bio_in_progress_wait[dir])))
1609 wake_up(&wc->bio_in_progress_wait[dir]);
1610 } else if (bio->bi_private == (void *)2) {
1611 dm_iot_io_end(&wc->iot, 1);
1612 }
1613 return 0;
1614}
1615
1616static int writecache_iterate_devices(struct dm_target *ti,
1617 iterate_devices_callout_fn fn, void *data)
1618{
1619 struct dm_writecache *wc = ti->private;
1620
1621 return fn(ti, wc->dev, 0, ti->len, data);
1622}
1623
1624static void writecache_io_hints(struct dm_target *ti, struct queue_limits *limits)
1625{
1626 struct dm_writecache *wc = ti->private;
1627
1628 if (limits->logical_block_size < wc->block_size)
1629 limits->logical_block_size = wc->block_size;
1630
1631 if (limits->physical_block_size < wc->block_size)
1632 limits->physical_block_size = wc->block_size;
1633
1634 if (limits->io_min < wc->block_size)
1635 limits->io_min = wc->block_size;
1636}
1637
1638
1639static void writecache_writeback_endio(struct bio *bio)
1640{
1641 struct writeback_struct *wb = container_of(bio, struct writeback_struct, bio);
1642 struct dm_writecache *wc = wb->wc;
1643 unsigned long flags;
1644
1645 raw_spin_lock_irqsave(&wc->endio_list_lock, flags);
1646 if (unlikely(list_empty(&wc->endio_list)))
1647 wake_up_process(wc->endio_thread);
1648 list_add_tail(&wb->endio_entry, &wc->endio_list);
1649 raw_spin_unlock_irqrestore(&wc->endio_list_lock, flags);
1650}
1651
1652static void writecache_copy_endio(int read_err, unsigned long write_err, void *ptr)
1653{
1654 struct copy_struct *c = ptr;
1655 struct dm_writecache *wc = c->wc;
1656
1657 c->error = likely(!(read_err | write_err)) ? 0 : -EIO;
1658
1659 raw_spin_lock_irq(&wc->endio_list_lock);
1660 if (unlikely(list_empty(&wc->endio_list)))
1661 wake_up_process(wc->endio_thread);
1662 list_add_tail(&c->endio_entry, &wc->endio_list);
1663 raw_spin_unlock_irq(&wc->endio_list_lock);
1664}
1665
1666static void __writecache_endio_pmem(struct dm_writecache *wc, struct list_head *list)
1667{
1668 unsigned i;
1669 struct writeback_struct *wb;
1670 struct wc_entry *e;
1671 unsigned long n_walked = 0;
1672
1673 do {
1674 wb = list_entry(list->next, struct writeback_struct, endio_entry);
1675 list_del(&wb->endio_entry);
1676
1677 if (unlikely(wb->bio.bi_status != BLK_STS_OK))
1678 writecache_error(wc, blk_status_to_errno(wb->bio.bi_status),
1679 "write error %d", wb->bio.bi_status);
1680 i = 0;
1681 do {
1682 e = wb->wc_list[i];
1683 BUG_ON(!e->write_in_progress);
1684 e->write_in_progress = false;
1685 INIT_LIST_HEAD(&e->lru);
1686 if (!writecache_has_error(wc))
1687 writecache_free_entry(wc, e);
1688 BUG_ON(!wc->writeback_size);
1689 wc->writeback_size--;
1690 n_walked++;
1691 if (unlikely(n_walked >= ENDIO_LATENCY)) {
1692 writecache_commit_flushed(wc, false);
1693 wc_unlock(wc);
1694 wc_lock(wc);
1695 n_walked = 0;
1696 }
1697 } while (++i < wb->wc_list_n);
1698
1699 if (wb->wc_list != wb->wc_list_inline)
1700 kfree(wb->wc_list);
1701 bio_put(&wb->bio);
1702 } while (!list_empty(list));
1703}
1704
1705static void __writecache_endio_ssd(struct dm_writecache *wc, struct list_head *list)
1706{
1707 struct copy_struct *c;
1708 struct wc_entry *e;
1709
1710 do {
1711 c = list_entry(list->next, struct copy_struct, endio_entry);
1712 list_del(&c->endio_entry);
1713
1714 if (unlikely(c->error))
1715 writecache_error(wc, c->error, "copy error");
1716
1717 e = c->e;
1718 do {
1719 BUG_ON(!e->write_in_progress);
1720 e->write_in_progress = false;
1721 INIT_LIST_HEAD(&e->lru);
1722 if (!writecache_has_error(wc))
1723 writecache_free_entry(wc, e);
1724
1725 BUG_ON(!wc->writeback_size);
1726 wc->writeback_size--;
1727 e++;
1728 } while (--c->n_entries);
1729 mempool_free(c, &wc->copy_pool);
1730 } while (!list_empty(list));
1731}
1732
1733static int writecache_endio_thread(void *data)
1734{
1735 struct dm_writecache *wc = data;
1736
1737 while (1) {
1738 struct list_head list;
1739
1740 raw_spin_lock_irq(&wc->endio_list_lock);
1741 if (!list_empty(&wc->endio_list))
1742 goto pop_from_list;
1743 set_current_state(TASK_INTERRUPTIBLE);
1744 raw_spin_unlock_irq(&wc->endio_list_lock);
1745
1746 if (unlikely(kthread_should_stop())) {
1747 set_current_state(TASK_RUNNING);
1748 break;
1749 }
1750
1751 schedule();
1752
1753 continue;
1754
1755pop_from_list:
1756 list = wc->endio_list;
1757 list.next->prev = list.prev->next = &list;
1758 INIT_LIST_HEAD(&wc->endio_list);
1759 raw_spin_unlock_irq(&wc->endio_list_lock);
1760
1761 if (!WC_MODE_FUA(wc))
1762 writecache_disk_flush(wc, wc->dev);
1763
1764 wc_lock(wc);
1765
1766 if (WC_MODE_PMEM(wc)) {
1767 __writecache_endio_pmem(wc, &list);
1768 } else {
1769 __writecache_endio_ssd(wc, &list);
1770 writecache_wait_for_ios(wc, READ);
1771 }
1772
1773 writecache_commit_flushed(wc, false);
1774
1775 wc_unlock(wc);
1776 }
1777
1778 return 0;
1779}
1780
1781static bool wc_add_block(struct writeback_struct *wb, struct wc_entry *e)
1782{
1783 struct dm_writecache *wc = wb->wc;
1784 unsigned block_size = wc->block_size;
1785 void *address = memory_data(wc, e);
1786
1787 persistent_memory_flush_cache(address, block_size);
1788
1789 if (unlikely(bio_end_sector(&wb->bio) >= wc->data_device_sectors))
1790 return true;
1791
1792 return bio_add_page(&wb->bio, persistent_memory_page(address),
1793 block_size, persistent_memory_page_offset(address)) != 0;
1794}
1795
1796struct writeback_list {
1797 struct list_head list;
1798 size_t size;
1799};
1800
1801static void __writeback_throttle(struct dm_writecache *wc, struct writeback_list *wbl)
1802{
1803 if (unlikely(wc->max_writeback_jobs)) {
1804 if (READ_ONCE(wc->writeback_size) - wbl->size >= wc->max_writeback_jobs) {
1805 wc_lock(wc);
1806 while (wc->writeback_size - wbl->size >= wc->max_writeback_jobs)
1807 writecache_wait_on_freelist(wc);
1808 wc_unlock(wc);
1809 }
1810 }
1811 cond_resched();
1812}
1813
1814static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeback_list *wbl)
1815{
1816 struct wc_entry *e, *f;
1817 struct bio *bio;
1818 struct writeback_struct *wb;
1819 unsigned max_pages;
1820
1821 while (wbl->size) {
1822 wbl->size--;
1823 e = container_of(wbl->list.prev, struct wc_entry, lru);
1824 list_del(&e->lru);
1825
1826 max_pages = e->wc_list_contiguous;
1827
1828 bio = bio_alloc_bioset(wc->dev->bdev, max_pages, REQ_OP_WRITE,
1829 GFP_NOIO, &wc->bio_set);
1830 wb = container_of(bio, struct writeback_struct, bio);
1831 wb->wc = wc;
1832 bio->bi_end_io = writecache_writeback_endio;
1833 bio->bi_iter.bi_sector = read_original_sector(wc, e);
1834 if (max_pages <= WB_LIST_INLINE ||
1835 unlikely(!(wb->wc_list = kmalloc_array(max_pages, sizeof(struct wc_entry *),
1836 GFP_NOIO | __GFP_NORETRY |
1837 __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
1838 wb->wc_list = wb->wc_list_inline;
1839 max_pages = WB_LIST_INLINE;
1840 }
1841
1842 BUG_ON(!wc_add_block(wb, e));
1843
1844 wb->wc_list[0] = e;
1845 wb->wc_list_n = 1;
1846
1847 while (wbl->size && wb->wc_list_n < max_pages) {
1848 f = container_of(wbl->list.prev, struct wc_entry, lru);
1849 if (read_original_sector(wc, f) !=
1850 read_original_sector(wc, e) + (wc->block_size >> SECTOR_SHIFT))
1851 break;
1852 if (!wc_add_block(wb, f))
1853 break;
1854 wbl->size--;
1855 list_del(&f->lru);
1856 wb->wc_list[wb->wc_list_n++] = f;
1857 e = f;
1858 }
1859 if (WC_MODE_FUA(wc))
1860 bio->bi_opf |= REQ_FUA;
1861 if (writecache_has_error(wc)) {
1862 bio->bi_status = BLK_STS_IOERR;
1863 bio_endio(bio);
1864 } else if (unlikely(!bio_sectors(bio))) {
1865 bio->bi_status = BLK_STS_OK;
1866 bio_endio(bio);
1867 } else {
1868 submit_bio(bio);
1869 }
1870
1871 __writeback_throttle(wc, wbl);
1872 }
1873}
1874
1875static void __writecache_writeback_ssd(struct dm_writecache *wc, struct writeback_list *wbl)
1876{
1877 struct wc_entry *e, *f;
1878 struct dm_io_region from, to;
1879 struct copy_struct *c;
1880
1881 while (wbl->size) {
1882 unsigned n_sectors;
1883
1884 wbl->size--;
1885 e = container_of(wbl->list.prev, struct wc_entry, lru);
1886 list_del(&e->lru);
1887
1888 n_sectors = e->wc_list_contiguous << (wc->block_size_bits - SECTOR_SHIFT);
1889
1890 from.bdev = wc->ssd_dev->bdev;
1891 from.sector = cache_sector(wc, e);
1892 from.count = n_sectors;
1893 to.bdev = wc->dev->bdev;
1894 to.sector = read_original_sector(wc, e);
1895 to.count = n_sectors;
1896
1897 c = mempool_alloc(&wc->copy_pool, GFP_NOIO);
1898 c->wc = wc;
1899 c->e = e;
1900 c->n_entries = e->wc_list_contiguous;
1901
1902 while ((n_sectors -= wc->block_size >> SECTOR_SHIFT)) {
1903 wbl->size--;
1904 f = container_of(wbl->list.prev, struct wc_entry, lru);
1905 BUG_ON(f != e + 1);
1906 list_del(&f->lru);
1907 e = f;
1908 }
1909
1910 if (unlikely(to.sector + to.count > wc->data_device_sectors)) {
1911 if (to.sector >= wc->data_device_sectors) {
1912 writecache_copy_endio(0, 0, c);
1913 continue;
1914 }
1915 from.count = to.count = wc->data_device_sectors - to.sector;
1916 }
1917
1918 dm_kcopyd_copy(wc->dm_kcopyd, &from, 1, &to, 0, writecache_copy_endio, c);
1919
1920 __writeback_throttle(wc, wbl);
1921 }
1922}
1923
1924static void writecache_writeback(struct work_struct *work)
1925{
1926 struct dm_writecache *wc = container_of(work, struct dm_writecache, writeback_work);
1927 struct blk_plug plug;
1928 struct wc_entry *f, *g, *e = NULL;
1929 struct rb_node *node, *next_node;
1930 struct list_head skipped;
1931 struct writeback_list wbl;
1932 unsigned long n_walked;
1933
1934 if (!WC_MODE_PMEM(wc)) {
1935 /* Wait for any active kcopyd work on behalf of ssd writeback */
1936 dm_kcopyd_client_flush(wc->dm_kcopyd);
1937 }
1938
1939 if (likely(wc->pause != 0)) {
1940 while (1) {
1941 unsigned long idle;
1942 if (unlikely(wc->cleaner) || unlikely(wc->writeback_all) ||
1943 unlikely(dm_suspended(wc->ti)))
1944 break;
1945 idle = dm_iot_idle_time(&wc->iot);
1946 if (idle >= wc->pause)
1947 break;
1948 idle = wc->pause - idle;
1949 if (idle > HZ)
1950 idle = HZ;
1951 schedule_timeout_idle(idle);
1952 }
1953 }
1954
1955 wc_lock(wc);
1956restart:
1957 if (writecache_has_error(wc)) {
1958 wc_unlock(wc);
1959 return;
1960 }
1961
1962 if (unlikely(wc->writeback_all)) {
1963 if (writecache_wait_for_writeback(wc))
1964 goto restart;
1965 }
1966
1967 if (wc->overwrote_committed) {
1968 writecache_wait_for_ios(wc, WRITE);
1969 }
1970
1971 n_walked = 0;
1972 INIT_LIST_HEAD(&skipped);
1973 INIT_LIST_HEAD(&wbl.list);
1974 wbl.size = 0;
1975 while (!list_empty(&wc->lru) &&
1976 (wc->writeback_all ||
1977 wc->freelist_size + wc->writeback_size <= wc->freelist_low_watermark ||
1978 (jiffies - container_of(wc->lru.prev, struct wc_entry, lru)->age >=
1979 wc->max_age - wc->max_age / MAX_AGE_DIV))) {
1980
1981 n_walked++;
1982 if (unlikely(n_walked > WRITEBACK_LATENCY) &&
1983 likely(!wc->writeback_all)) {
1984 if (likely(!dm_suspended(wc->ti)))
1985 queue_work(wc->writeback_wq, &wc->writeback_work);
1986 break;
1987 }
1988
1989 if (unlikely(wc->writeback_all)) {
1990 if (unlikely(!e)) {
1991 writecache_flush(wc);
1992 e = container_of(rb_first(&wc->tree), struct wc_entry, rb_node);
1993 } else
1994 e = g;
1995 } else
1996 e = container_of(wc->lru.prev, struct wc_entry, lru);
1997 BUG_ON(e->write_in_progress);
1998 if (unlikely(!writecache_entry_is_committed(wc, e))) {
1999 writecache_flush(wc);
2000 }
2001 node = rb_prev(&e->rb_node);
2002 if (node) {
2003 f = container_of(node, struct wc_entry, rb_node);
2004 if (unlikely(read_original_sector(wc, f) ==
2005 read_original_sector(wc, e))) {
2006 BUG_ON(!f->write_in_progress);
2007 list_move(&e->lru, &skipped);
2008 cond_resched();
2009 continue;
2010 }
2011 }
2012 wc->writeback_size++;
2013 list_move(&e->lru, &wbl.list);
2014 wbl.size++;
2015 e->write_in_progress = true;
2016 e->wc_list_contiguous = 1;
2017
2018 f = e;
2019
2020 while (1) {
2021 next_node = rb_next(&f->rb_node);
2022 if (unlikely(!next_node))
2023 break;
2024 g = container_of(next_node, struct wc_entry, rb_node);
2025 if (unlikely(read_original_sector(wc, g) ==
2026 read_original_sector(wc, f))) {
2027 f = g;
2028 continue;
2029 }
2030 if (read_original_sector(wc, g) !=
2031 read_original_sector(wc, f) + (wc->block_size >> SECTOR_SHIFT))
2032 break;
2033 if (unlikely(g->write_in_progress))
2034 break;
2035 if (unlikely(!writecache_entry_is_committed(wc, g)))
2036 break;
2037
2038 if (!WC_MODE_PMEM(wc)) {
2039 if (g != f + 1)
2040 break;
2041 }
2042
2043 n_walked++;
2044 //if (unlikely(n_walked > WRITEBACK_LATENCY) && likely(!wc->writeback_all))
2045 // break;
2046
2047 wc->writeback_size++;
2048 list_move(&g->lru, &wbl.list);
2049 wbl.size++;
2050 g->write_in_progress = true;
2051 g->wc_list_contiguous = BIO_MAX_VECS;
2052 f = g;
2053 e->wc_list_contiguous++;
2054 if (unlikely(e->wc_list_contiguous == BIO_MAX_VECS)) {
2055 if (unlikely(wc->writeback_all)) {
2056 next_node = rb_next(&f->rb_node);
2057 if (likely(next_node))
2058 g = container_of(next_node, struct wc_entry, rb_node);
2059 }
2060 break;
2061 }
2062 }
2063 cond_resched();
2064 }
2065
2066 if (!list_empty(&skipped)) {
2067 list_splice_tail(&skipped, &wc->lru);
2068 /*
2069 * If we didn't do any progress, we must wait until some
2070 * writeback finishes to avoid burning CPU in a loop
2071 */
2072 if (unlikely(!wbl.size))
2073 writecache_wait_for_writeback(wc);
2074 }
2075
2076 wc_unlock(wc);
2077
2078 blk_start_plug(&plug);
2079
2080 if (WC_MODE_PMEM(wc))
2081 __writecache_writeback_pmem(wc, &wbl);
2082 else
2083 __writecache_writeback_ssd(wc, &wbl);
2084
2085 blk_finish_plug(&plug);
2086
2087 if (unlikely(wc->writeback_all)) {
2088 wc_lock(wc);
2089 while (writecache_wait_for_writeback(wc));
2090 wc_unlock(wc);
2091 }
2092}
2093
2094static int calculate_memory_size(uint64_t device_size, unsigned block_size,
2095 size_t *n_blocks_p, size_t *n_metadata_blocks_p)
2096{
2097 uint64_t n_blocks, offset;
2098 struct wc_entry e;
2099
2100 n_blocks = device_size;
2101 do_div(n_blocks, block_size + sizeof(struct wc_memory_entry));
2102
2103 while (1) {
2104 if (!n_blocks)
2105 return -ENOSPC;
2106 /* Verify the following entries[n_blocks] won't overflow */
2107 if (n_blocks >= ((size_t)-sizeof(struct wc_memory_superblock) /
2108 sizeof(struct wc_memory_entry)))
2109 return -EFBIG;
2110 offset = offsetof(struct wc_memory_superblock, entries[n_blocks]);
2111 offset = (offset + block_size - 1) & ~(uint64_t)(block_size - 1);
2112 if (offset + n_blocks * block_size <= device_size)
2113 break;
2114 n_blocks--;
2115 }
2116
2117 /* check if the bit field overflows */
2118 e.index = n_blocks;
2119 if (e.index != n_blocks)
2120 return -EFBIG;
2121
2122 if (n_blocks_p)
2123 *n_blocks_p = n_blocks;
2124 if (n_metadata_blocks_p)
2125 *n_metadata_blocks_p = offset >> __ffs(block_size);
2126 return 0;
2127}
2128
2129static int init_memory(struct dm_writecache *wc)
2130{
2131 size_t b;
2132 int r;
2133
2134 r = calculate_memory_size(wc->memory_map_size, wc->block_size, &wc->n_blocks, NULL);
2135 if (r)
2136 return r;
2137
2138 r = writecache_alloc_entries(wc);
2139 if (r)
2140 return r;
2141
2142 for (b = 0; b < ARRAY_SIZE(sb(wc)->padding); b++)
2143 pmem_assign(sb(wc)->padding[b], cpu_to_le64(0));
2144 pmem_assign(sb(wc)->version, cpu_to_le32(MEMORY_SUPERBLOCK_VERSION));
2145 pmem_assign(sb(wc)->block_size, cpu_to_le32(wc->block_size));
2146 pmem_assign(sb(wc)->n_blocks, cpu_to_le64(wc->n_blocks));
2147 pmem_assign(sb(wc)->seq_count, cpu_to_le64(0));
2148
2149 for (b = 0; b < wc->n_blocks; b++) {
2150 write_original_sector_seq_count(wc, &wc->entries[b], -1, -1);
2151 cond_resched();
2152 }
2153
2154 writecache_flush_all_metadata(wc);
2155 writecache_commit_flushed(wc, false);
2156 pmem_assign(sb(wc)->magic, cpu_to_le32(MEMORY_SUPERBLOCK_MAGIC));
2157 writecache_flush_region(wc, &sb(wc)->magic, sizeof sb(wc)->magic);
2158 writecache_commit_flushed(wc, false);
2159
2160 return 0;
2161}
2162
2163static void writecache_dtr(struct dm_target *ti)
2164{
2165 struct dm_writecache *wc = ti->private;
2166
2167 if (!wc)
2168 return;
2169
2170 if (wc->endio_thread)
2171 kthread_stop(wc->endio_thread);
2172
2173 if (wc->flush_thread)
2174 kthread_stop(wc->flush_thread);
2175
2176 bioset_exit(&wc->bio_set);
2177
2178 mempool_exit(&wc->copy_pool);
2179
2180 if (wc->writeback_wq)
2181 destroy_workqueue(wc->writeback_wq);
2182
2183 if (wc->dev)
2184 dm_put_device(ti, wc->dev);
2185
2186 if (wc->ssd_dev)
2187 dm_put_device(ti, wc->ssd_dev);
2188
2189 vfree(wc->entries);
2190
2191 if (wc->memory_map) {
2192 if (WC_MODE_PMEM(wc))
2193 persistent_memory_release(wc);
2194 else
2195 vfree(wc->memory_map);
2196 }
2197
2198 if (wc->dm_kcopyd)
2199 dm_kcopyd_client_destroy(wc->dm_kcopyd);
2200
2201 if (wc->dm_io)
2202 dm_io_client_destroy(wc->dm_io);
2203
2204 vfree(wc->dirty_bitmap);
2205
2206 kfree(wc);
2207}
2208
2209static int writecache_ctr(struct dm_target *ti, unsigned argc, char **argv)
2210{
2211 struct dm_writecache *wc;
2212 struct dm_arg_set as;
2213 const char *string;
2214 unsigned opt_params;
2215 size_t offset, data_size;
2216 int i, r;
2217 char dummy;
2218 int high_wm_percent = HIGH_WATERMARK;
2219 int low_wm_percent = LOW_WATERMARK;
2220 uint64_t x;
2221 struct wc_memory_superblock s;
2222
2223 static struct dm_arg _args[] = {
2224 {0, 18, "Invalid number of feature args"},
2225 };
2226
2227 as.argc = argc;
2228 as.argv = argv;
2229
2230 wc = kzalloc(sizeof(struct dm_writecache), GFP_KERNEL);
2231 if (!wc) {
2232 ti->error = "Cannot allocate writecache structure";
2233 r = -ENOMEM;
2234 goto bad;
2235 }
2236 ti->private = wc;
2237 wc->ti = ti;
2238
2239 mutex_init(&wc->lock);
2240 wc->max_age = MAX_AGE_UNSPECIFIED;
2241 writecache_poison_lists(wc);
2242 init_waitqueue_head(&wc->freelist_wait);
2243 timer_setup(&wc->autocommit_timer, writecache_autocommit_timer, 0);
2244 timer_setup(&wc->max_age_timer, writecache_max_age_timer, 0);
2245
2246 for (i = 0; i < 2; i++) {
2247 atomic_set(&wc->bio_in_progress[i], 0);
2248 init_waitqueue_head(&wc->bio_in_progress_wait[i]);
2249 }
2250
2251 wc->dm_io = dm_io_client_create();
2252 if (IS_ERR(wc->dm_io)) {
2253 r = PTR_ERR(wc->dm_io);
2254 ti->error = "Unable to allocate dm-io client";
2255 wc->dm_io = NULL;
2256 goto bad;
2257 }
2258
2259 wc->writeback_wq = alloc_workqueue("writecache-writeback", WQ_MEM_RECLAIM, 1);
2260 if (!wc->writeback_wq) {
2261 r = -ENOMEM;
2262 ti->error = "Could not allocate writeback workqueue";
2263 goto bad;
2264 }
2265 INIT_WORK(&wc->writeback_work, writecache_writeback);
2266 INIT_WORK(&wc->flush_work, writecache_flush_work);
2267
2268 dm_iot_init(&wc->iot);
2269
2270 raw_spin_lock_init(&wc->endio_list_lock);
2271 INIT_LIST_HEAD(&wc->endio_list);
2272 wc->endio_thread = kthread_run(writecache_endio_thread, wc, "writecache_endio");
2273 if (IS_ERR(wc->endio_thread)) {
2274 r = PTR_ERR(wc->endio_thread);
2275 wc->endio_thread = NULL;
2276 ti->error = "Couldn't spawn endio thread";
2277 goto bad;
2278 }
2279
2280 /*
2281 * Parse the mode (pmem or ssd)
2282 */
2283 string = dm_shift_arg(&as);
2284 if (!string)
2285 goto bad_arguments;
2286
2287 if (!strcasecmp(string, "s")) {
2288 wc->pmem_mode = false;
2289 } else if (!strcasecmp(string, "p")) {
2290#ifdef DM_WRITECACHE_HAS_PMEM
2291 wc->pmem_mode = true;
2292 wc->writeback_fua = true;
2293#else
2294 /*
2295 * If the architecture doesn't support persistent memory or
2296 * the kernel doesn't support any DAX drivers, this driver can
2297 * only be used in SSD-only mode.
2298 */
2299 r = -EOPNOTSUPP;
2300 ti->error = "Persistent memory or DAX not supported on this system";
2301 goto bad;
2302#endif
2303 } else {
2304 goto bad_arguments;
2305 }
2306
2307 if (WC_MODE_PMEM(wc)) {
2308 r = bioset_init(&wc->bio_set, BIO_POOL_SIZE,
2309 offsetof(struct writeback_struct, bio),
2310 BIOSET_NEED_BVECS);
2311 if (r) {
2312 ti->error = "Could not allocate bio set";
2313 goto bad;
2314 }
2315 } else {
2316 wc->pause = PAUSE_WRITEBACK;
2317 r = mempool_init_kmalloc_pool(&wc->copy_pool, 1, sizeof(struct copy_struct));
2318 if (r) {
2319 ti->error = "Could not allocate mempool";
2320 goto bad;
2321 }
2322 }
2323
2324 /*
2325 * Parse the origin data device
2326 */
2327 string = dm_shift_arg(&as);
2328 if (!string)
2329 goto bad_arguments;
2330 r = dm_get_device(ti, string, dm_table_get_mode(ti->table), &wc->dev);
2331 if (r) {
2332 ti->error = "Origin data device lookup failed";
2333 goto bad;
2334 }
2335
2336 /*
2337 * Parse cache data device (be it pmem or ssd)
2338 */
2339 string = dm_shift_arg(&as);
2340 if (!string)
2341 goto bad_arguments;
2342
2343 r = dm_get_device(ti, string, dm_table_get_mode(ti->table), &wc->ssd_dev);
2344 if (r) {
2345 ti->error = "Cache data device lookup failed";
2346 goto bad;
2347 }
2348 wc->memory_map_size = bdev_nr_bytes(wc->ssd_dev->bdev);
2349
2350 /*
2351 * Parse the cache block size
2352 */
2353 string = dm_shift_arg(&as);
2354 if (!string)
2355 goto bad_arguments;
2356 if (sscanf(string, "%u%c", &wc->block_size, &dummy) != 1 ||
2357 wc->block_size < 512 || wc->block_size > PAGE_SIZE ||
2358 (wc->block_size & (wc->block_size - 1))) {
2359 r = -EINVAL;
2360 ti->error = "Invalid block size";
2361 goto bad;
2362 }
2363 if (wc->block_size < bdev_logical_block_size(wc->dev->bdev) ||
2364 wc->block_size < bdev_logical_block_size(wc->ssd_dev->bdev)) {
2365 r = -EINVAL;
2366 ti->error = "Block size is smaller than device logical block size";
2367 goto bad;
2368 }
2369 wc->block_size_bits = __ffs(wc->block_size);
2370
2371 wc->max_writeback_jobs = MAX_WRITEBACK_JOBS;
2372 wc->autocommit_blocks = !WC_MODE_PMEM(wc) ? AUTOCOMMIT_BLOCKS_SSD : AUTOCOMMIT_BLOCKS_PMEM;
2373 wc->autocommit_jiffies = msecs_to_jiffies(AUTOCOMMIT_MSEC);
2374
2375 /*
2376 * Parse optional arguments
2377 */
2378 r = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
2379 if (r)
2380 goto bad;
2381
2382 while (opt_params) {
2383 string = dm_shift_arg(&as), opt_params--;
2384 if (!strcasecmp(string, "start_sector") && opt_params >= 1) {
2385 unsigned long long start_sector;
2386 string = dm_shift_arg(&as), opt_params--;
2387 if (sscanf(string, "%llu%c", &start_sector, &dummy) != 1)
2388 goto invalid_optional;
2389 wc->start_sector = start_sector;
2390 wc->start_sector_set = true;
2391 if (wc->start_sector != start_sector ||
2392 wc->start_sector >= wc->memory_map_size >> SECTOR_SHIFT)
2393 goto invalid_optional;
2394 } else if (!strcasecmp(string, "high_watermark") && opt_params >= 1) {
2395 string = dm_shift_arg(&as), opt_params--;
2396 if (sscanf(string, "%d%c", &high_wm_percent, &dummy) != 1)
2397 goto invalid_optional;
2398 if (high_wm_percent < 0 || high_wm_percent > 100)
2399 goto invalid_optional;
2400 wc->high_wm_percent_value = high_wm_percent;
2401 wc->high_wm_percent_set = true;
2402 } else if (!strcasecmp(string, "low_watermark") && opt_params >= 1) {
2403 string = dm_shift_arg(&as), opt_params--;
2404 if (sscanf(string, "%d%c", &low_wm_percent, &dummy) != 1)
2405 goto invalid_optional;
2406 if (low_wm_percent < 0 || low_wm_percent > 100)
2407 goto invalid_optional;
2408 wc->low_wm_percent_value = low_wm_percent;
2409 wc->low_wm_percent_set = true;
2410 } else if (!strcasecmp(string, "writeback_jobs") && opt_params >= 1) {
2411 string = dm_shift_arg(&as), opt_params--;
2412 if (sscanf(string, "%u%c", &wc->max_writeback_jobs, &dummy) != 1)
2413 goto invalid_optional;
2414 wc->max_writeback_jobs_set = true;
2415 } else if (!strcasecmp(string, "autocommit_blocks") && opt_params >= 1) {
2416 string = dm_shift_arg(&as), opt_params--;
2417 if (sscanf(string, "%u%c", &wc->autocommit_blocks, &dummy) != 1)
2418 goto invalid_optional;
2419 wc->autocommit_blocks_set = true;
2420 } else if (!strcasecmp(string, "autocommit_time") && opt_params >= 1) {
2421 unsigned autocommit_msecs;
2422 string = dm_shift_arg(&as), opt_params--;
2423 if (sscanf(string, "%u%c", &autocommit_msecs, &dummy) != 1)
2424 goto invalid_optional;
2425 if (autocommit_msecs > 3600000)
2426 goto invalid_optional;
2427 wc->autocommit_jiffies = msecs_to_jiffies(autocommit_msecs);
2428 wc->autocommit_time_value = autocommit_msecs;
2429 wc->autocommit_time_set = true;
2430 } else if (!strcasecmp(string, "max_age") && opt_params >= 1) {
2431 unsigned max_age_msecs;
2432 string = dm_shift_arg(&as), opt_params--;
2433 if (sscanf(string, "%u%c", &max_age_msecs, &dummy) != 1)
2434 goto invalid_optional;
2435 if (max_age_msecs > 86400000)
2436 goto invalid_optional;
2437 wc->max_age = msecs_to_jiffies(max_age_msecs);
2438 wc->max_age_set = true;
2439 wc->max_age_value = max_age_msecs;
2440 } else if (!strcasecmp(string, "cleaner")) {
2441 wc->cleaner_set = true;
2442 wc->cleaner = true;
2443 } else if (!strcasecmp(string, "fua")) {
2444 if (WC_MODE_PMEM(wc)) {
2445 wc->writeback_fua = true;
2446 wc->writeback_fua_set = true;
2447 } else goto invalid_optional;
2448 } else if (!strcasecmp(string, "nofua")) {
2449 if (WC_MODE_PMEM(wc)) {
2450 wc->writeback_fua = false;
2451 wc->writeback_fua_set = true;
2452 } else goto invalid_optional;
2453 } else if (!strcasecmp(string, "metadata_only")) {
2454 wc->metadata_only = true;
2455 } else if (!strcasecmp(string, "pause_writeback") && opt_params >= 1) {
2456 unsigned pause_msecs;
2457 if (WC_MODE_PMEM(wc))
2458 goto invalid_optional;
2459 string = dm_shift_arg(&as), opt_params--;
2460 if (sscanf(string, "%u%c", &pause_msecs, &dummy) != 1)
2461 goto invalid_optional;
2462 if (pause_msecs > 60000)
2463 goto invalid_optional;
2464 wc->pause = msecs_to_jiffies(pause_msecs);
2465 wc->pause_set = true;
2466 wc->pause_value = pause_msecs;
2467 } else {
2468invalid_optional:
2469 r = -EINVAL;
2470 ti->error = "Invalid optional argument";
2471 goto bad;
2472 }
2473 }
2474
2475 if (high_wm_percent < low_wm_percent) {
2476 r = -EINVAL;
2477 ti->error = "High watermark must be greater than or equal to low watermark";
2478 goto bad;
2479 }
2480
2481 if (WC_MODE_PMEM(wc)) {
2482 if (!dax_synchronous(wc->ssd_dev->dax_dev)) {
2483 r = -EOPNOTSUPP;
2484 ti->error = "Asynchronous persistent memory not supported as pmem cache";
2485 goto bad;
2486 }
2487
2488 r = persistent_memory_claim(wc);
2489 if (r) {
2490 ti->error = "Unable to map persistent memory for cache";
2491 goto bad;
2492 }
2493 } else {
2494 size_t n_blocks, n_metadata_blocks;
2495 uint64_t n_bitmap_bits;
2496
2497 wc->memory_map_size -= (uint64_t)wc->start_sector << SECTOR_SHIFT;
2498
2499 bio_list_init(&wc->flush_list);
2500 wc->flush_thread = kthread_run(writecache_flush_thread, wc, "dm_writecache_flush");
2501 if (IS_ERR(wc->flush_thread)) {
2502 r = PTR_ERR(wc->flush_thread);
2503 wc->flush_thread = NULL;
2504 ti->error = "Couldn't spawn flush thread";
2505 goto bad;
2506 }
2507
2508 r = calculate_memory_size(wc->memory_map_size, wc->block_size,
2509 &n_blocks, &n_metadata_blocks);
2510 if (r) {
2511 ti->error = "Invalid device size";
2512 goto bad;
2513 }
2514
2515 n_bitmap_bits = (((uint64_t)n_metadata_blocks << wc->block_size_bits) +
2516 BITMAP_GRANULARITY - 1) / BITMAP_GRANULARITY;
2517 /* this is limitation of test_bit functions */
2518 if (n_bitmap_bits > 1U << 31) {
2519 r = -EFBIG;
2520 ti->error = "Invalid device size";
2521 goto bad;
2522 }
2523
2524 wc->memory_map = vmalloc(n_metadata_blocks << wc->block_size_bits);
2525 if (!wc->memory_map) {
2526 r = -ENOMEM;
2527 ti->error = "Unable to allocate memory for metadata";
2528 goto bad;
2529 }
2530
2531 wc->dm_kcopyd = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2532 if (IS_ERR(wc->dm_kcopyd)) {
2533 r = PTR_ERR(wc->dm_kcopyd);
2534 ti->error = "Unable to allocate dm-kcopyd client";
2535 wc->dm_kcopyd = NULL;
2536 goto bad;
2537 }
2538
2539 wc->metadata_sectors = n_metadata_blocks << (wc->block_size_bits - SECTOR_SHIFT);
2540 wc->dirty_bitmap_size = (n_bitmap_bits + BITS_PER_LONG - 1) /
2541 BITS_PER_LONG * sizeof(unsigned long);
2542 wc->dirty_bitmap = vzalloc(wc->dirty_bitmap_size);
2543 if (!wc->dirty_bitmap) {
2544 r = -ENOMEM;
2545 ti->error = "Unable to allocate dirty bitmap";
2546 goto bad;
2547 }
2548
2549 r = writecache_read_metadata(wc, wc->block_size >> SECTOR_SHIFT);
2550 if (r) {
2551 ti->error = "Unable to read first block of metadata";
2552 goto bad;
2553 }
2554 }
2555
2556 r = copy_mc_to_kernel(&s, sb(wc), sizeof(struct wc_memory_superblock));
2557 if (r) {
2558 ti->error = "Hardware memory error when reading superblock";
2559 goto bad;
2560 }
2561 if (!le32_to_cpu(s.magic) && !le32_to_cpu(s.version)) {
2562 r = init_memory(wc);
2563 if (r) {
2564 ti->error = "Unable to initialize device";
2565 goto bad;
2566 }
2567 r = copy_mc_to_kernel(&s, sb(wc),
2568 sizeof(struct wc_memory_superblock));
2569 if (r) {
2570 ti->error = "Hardware memory error when reading superblock";
2571 goto bad;
2572 }
2573 }
2574
2575 if (le32_to_cpu(s.magic) != MEMORY_SUPERBLOCK_MAGIC) {
2576 ti->error = "Invalid magic in the superblock";
2577 r = -EINVAL;
2578 goto bad;
2579 }
2580
2581 if (le32_to_cpu(s.version) != MEMORY_SUPERBLOCK_VERSION) {
2582 ti->error = "Invalid version in the superblock";
2583 r = -EINVAL;
2584 goto bad;
2585 }
2586
2587 if (le32_to_cpu(s.block_size) != wc->block_size) {
2588 ti->error = "Block size does not match superblock";
2589 r = -EINVAL;
2590 goto bad;
2591 }
2592
2593 wc->n_blocks = le64_to_cpu(s.n_blocks);
2594
2595 offset = wc->n_blocks * sizeof(struct wc_memory_entry);
2596 if (offset / sizeof(struct wc_memory_entry) != le64_to_cpu(sb(wc)->n_blocks)) {
2597overflow:
2598 ti->error = "Overflow in size calculation";
2599 r = -EINVAL;
2600 goto bad;
2601 }
2602 offset += sizeof(struct wc_memory_superblock);
2603 if (offset < sizeof(struct wc_memory_superblock))
2604 goto overflow;
2605 offset = (offset + wc->block_size - 1) & ~(size_t)(wc->block_size - 1);
2606 data_size = wc->n_blocks * (size_t)wc->block_size;
2607 if (!offset || (data_size / wc->block_size != wc->n_blocks) ||
2608 (offset + data_size < offset))
2609 goto overflow;
2610 if (offset + data_size > wc->memory_map_size) {
2611 ti->error = "Memory area is too small";
2612 r = -EINVAL;
2613 goto bad;
2614 }
2615
2616 wc->metadata_sectors = offset >> SECTOR_SHIFT;
2617 wc->block_start = (char *)sb(wc) + offset;
2618
2619 x = (uint64_t)wc->n_blocks * (100 - high_wm_percent);
2620 x += 50;
2621 do_div(x, 100);
2622 wc->freelist_high_watermark = x;
2623 x = (uint64_t)wc->n_blocks * (100 - low_wm_percent);
2624 x += 50;
2625 do_div(x, 100);
2626 wc->freelist_low_watermark = x;
2627
2628 if (wc->cleaner)
2629 activate_cleaner(wc);
2630
2631 r = writecache_alloc_entries(wc);
2632 if (r) {
2633 ti->error = "Cannot allocate memory";
2634 goto bad;
2635 }
2636
2637 ti->num_flush_bios = WC_MODE_PMEM(wc) ? 1 : 2;
2638 ti->flush_supported = true;
2639 ti->num_discard_bios = 1;
2640
2641 if (WC_MODE_PMEM(wc))
2642 persistent_memory_flush_cache(wc->memory_map, wc->memory_map_size);
2643
2644 return 0;
2645
2646bad_arguments:
2647 r = -EINVAL;
2648 ti->error = "Bad arguments";
2649bad:
2650 writecache_dtr(ti);
2651 return r;
2652}
2653
2654static void writecache_status(struct dm_target *ti, status_type_t type,
2655 unsigned status_flags, char *result, unsigned maxlen)
2656{
2657 struct dm_writecache *wc = ti->private;
2658 unsigned extra_args;
2659 unsigned sz = 0;
2660
2661 switch (type) {
2662 case STATUSTYPE_INFO:
2663 DMEMIT("%ld %llu %llu %llu %llu %llu %llu %llu %llu %llu %llu %llu %llu %llu",
2664 writecache_has_error(wc),
2665 (unsigned long long)wc->n_blocks, (unsigned long long)wc->freelist_size,
2666 (unsigned long long)wc->writeback_size,
2667 wc->stats.reads,
2668 wc->stats.read_hits,
2669 wc->stats.writes,
2670 wc->stats.write_hits_uncommitted,
2671 wc->stats.write_hits_committed,
2672 wc->stats.writes_around,
2673 wc->stats.writes_allocate,
2674 wc->stats.writes_blocked_on_freelist,
2675 wc->stats.flushes,
2676 wc->stats.discards);
2677 break;
2678 case STATUSTYPE_TABLE:
2679 DMEMIT("%c %s %s %u ", WC_MODE_PMEM(wc) ? 'p' : 's',
2680 wc->dev->name, wc->ssd_dev->name, wc->block_size);
2681 extra_args = 0;
2682 if (wc->start_sector_set)
2683 extra_args += 2;
2684 if (wc->high_wm_percent_set)
2685 extra_args += 2;
2686 if (wc->low_wm_percent_set)
2687 extra_args += 2;
2688 if (wc->max_writeback_jobs_set)
2689 extra_args += 2;
2690 if (wc->autocommit_blocks_set)
2691 extra_args += 2;
2692 if (wc->autocommit_time_set)
2693 extra_args += 2;
2694 if (wc->max_age_set)
2695 extra_args += 2;
2696 if (wc->cleaner_set)
2697 extra_args++;
2698 if (wc->writeback_fua_set)
2699 extra_args++;
2700 if (wc->metadata_only)
2701 extra_args++;
2702 if (wc->pause_set)
2703 extra_args += 2;
2704
2705 DMEMIT("%u", extra_args);
2706 if (wc->start_sector_set)
2707 DMEMIT(" start_sector %llu", (unsigned long long)wc->start_sector);
2708 if (wc->high_wm_percent_set)
2709 DMEMIT(" high_watermark %u", wc->high_wm_percent_value);
2710 if (wc->low_wm_percent_set)
2711 DMEMIT(" low_watermark %u", wc->low_wm_percent_value);
2712 if (wc->max_writeback_jobs_set)
2713 DMEMIT(" writeback_jobs %u", wc->max_writeback_jobs);
2714 if (wc->autocommit_blocks_set)
2715 DMEMIT(" autocommit_blocks %u", wc->autocommit_blocks);
2716 if (wc->autocommit_time_set)
2717 DMEMIT(" autocommit_time %u", wc->autocommit_time_value);
2718 if (wc->max_age_set)
2719 DMEMIT(" max_age %u", wc->max_age_value);
2720 if (wc->cleaner_set)
2721 DMEMIT(" cleaner");
2722 if (wc->writeback_fua_set)
2723 DMEMIT(" %sfua", wc->writeback_fua ? "" : "no");
2724 if (wc->metadata_only)
2725 DMEMIT(" metadata_only");
2726 if (wc->pause_set)
2727 DMEMIT(" pause_writeback %u", wc->pause_value);
2728 break;
2729 case STATUSTYPE_IMA:
2730 *result = '\0';
2731 break;
2732 }
2733}
2734
2735static struct target_type writecache_target = {
2736 .name = "writecache",
2737 .version = {1, 6, 0},
2738 .module = THIS_MODULE,
2739 .ctr = writecache_ctr,
2740 .dtr = writecache_dtr,
2741 .status = writecache_status,
2742 .postsuspend = writecache_suspend,
2743 .resume = writecache_resume,
2744 .message = writecache_message,
2745 .map = writecache_map,
2746 .end_io = writecache_end_io,
2747 .iterate_devices = writecache_iterate_devices,
2748 .io_hints = writecache_io_hints,
2749};
2750
2751static int __init dm_writecache_init(void)
2752{
2753 int r;
2754
2755 r = dm_register_target(&writecache_target);
2756 if (r < 0) {
2757 DMERR("register failed %d", r);
2758 return r;
2759 }
2760
2761 return 0;
2762}
2763
2764static void __exit dm_writecache_exit(void)
2765{
2766 dm_unregister_target(&writecache_target);
2767}
2768
2769module_init(dm_writecache_init);
2770module_exit(dm_writecache_exit);
2771
2772MODULE_DESCRIPTION(DM_NAME " writecache target");
2773MODULE_AUTHOR("Mikulas Patocka <dm-devel@redhat.com>");
2774MODULE_LICENSE("GPL");