1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2018 Red Hat. All rights reserved.
5 * This file is released under the GPL.
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>
19 #define DM_MSG_PREFIX "writecache"
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 #define MAX_AGE_DIV 16
30 #define MAX_AGE_UNSPECIFIED -1UL
32 #define BITMAP_GRANULARITY 65536
33 #if BITMAP_GRANULARITY < PAGE_SIZE
34 #undef BITMAP_GRANULARITY
35 #define BITMAP_GRANULARITY PAGE_SIZE
38 #if IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API) && IS_ENABLED(CONFIG_DAX_DRIVER)
39 #define DM_WRITECACHE_HAS_PMEM
42 #ifdef DM_WRITECACHE_HAS_PMEM
43 #define pmem_assign(dest, src) \
45 typeof(dest) uniq = (src); \
46 memcpy_flushcache(&(dest), &uniq, sizeof(dest)); \
49 #define pmem_assign(dest, src) ((dest) = (src))
52 #if defined(__HAVE_ARCH_MEMCPY_MCSAFE) && defined(DM_WRITECACHE_HAS_PMEM)
53 #define DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
56 #define MEMORY_SUPERBLOCK_MAGIC 0x23489321
57 #define MEMORY_SUPERBLOCK_VERSION 1
59 struct wc_memory_entry {
60 __le64 original_sector;
64 struct wc_memory_superblock {
76 struct wc_memory_entry entries[0];
80 struct rb_node rb_node;
82 unsigned short wc_list_contiguous;
83 bool write_in_progress
84 #if BITS_PER_LONG == 64
89 #if BITS_PER_LONG == 64
94 #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
95 uint64_t original_sector;
100 #ifdef DM_WRITECACHE_HAS_PMEM
101 #define WC_MODE_PMEM(wc) ((wc)->pmem_mode)
102 #define WC_MODE_FUA(wc) ((wc)->writeback_fua)
104 #define WC_MODE_PMEM(wc) false
105 #define WC_MODE_FUA(wc) false
107 #define WC_MODE_SORT_FREELIST(wc) (!WC_MODE_PMEM(wc))
109 struct dm_writecache {
111 struct list_head lru;
113 struct list_head freelist;
115 struct rb_root freetree;
116 struct wc_entry *current_free;
121 size_t freelist_size;
122 size_t writeback_size;
123 size_t freelist_high_watermark;
124 size_t freelist_low_watermark;
125 unsigned long max_age;
127 unsigned uncommitted_blocks;
128 unsigned autocommit_blocks;
129 unsigned max_writeback_jobs;
133 unsigned long autocommit_jiffies;
134 struct timer_list autocommit_timer;
135 struct wait_queue_head freelist_wait;
137 struct timer_list max_age_timer;
139 atomic_t bio_in_progress[2];
140 struct wait_queue_head bio_in_progress_wait[2];
142 struct dm_target *ti;
144 struct dm_dev *ssd_dev;
145 sector_t start_sector;
147 uint64_t memory_map_size;
148 size_t metadata_sectors;
152 struct wc_entry *entries;
154 unsigned char block_size_bits;
157 bool writeback_fua:1;
159 bool overwrote_committed:1;
160 bool memory_vmapped:1;
162 bool high_wm_percent_set:1;
163 bool low_wm_percent_set:1;
164 bool max_writeback_jobs_set:1;
165 bool autocommit_blocks_set:1;
166 bool autocommit_time_set:1;
167 bool writeback_fua_set:1;
168 bool flush_on_suspend:1;
171 unsigned writeback_all;
172 struct workqueue_struct *writeback_wq;
173 struct work_struct writeback_work;
174 struct work_struct flush_work;
176 struct dm_io_client *dm_io;
178 raw_spinlock_t endio_list_lock;
179 struct list_head endio_list;
180 struct task_struct *endio_thread;
182 struct task_struct *flush_thread;
183 struct bio_list flush_list;
185 struct dm_kcopyd_client *dm_kcopyd;
186 unsigned long *dirty_bitmap;
187 unsigned dirty_bitmap_size;
189 struct bio_set bio_set;
193 #define WB_LIST_INLINE 16
195 struct writeback_struct {
196 struct list_head endio_entry;
197 struct dm_writecache *wc;
198 struct wc_entry **wc_list;
200 struct wc_entry *wc_list_inline[WB_LIST_INLINE];
205 struct list_head endio_entry;
206 struct dm_writecache *wc;
212 DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(dm_writecache_throttle,
213 "A percentage of time allocated for data copying");
215 static void wc_lock(struct dm_writecache *wc)
217 mutex_lock(&wc->lock);
220 static void wc_unlock(struct dm_writecache *wc)
222 mutex_unlock(&wc->lock);
225 #ifdef DM_WRITECACHE_HAS_PMEM
226 static int persistent_memory_claim(struct dm_writecache *wc)
235 wc->memory_vmapped = false;
237 if (!wc->ssd_dev->dax_dev) {
241 s = wc->memory_map_size;
247 if (p != s >> PAGE_SHIFT) {
252 id = dax_read_lock();
254 da = dax_direct_access(wc->ssd_dev->dax_dev, 0, p, &wc->memory_map, &pfn);
256 wc->memory_map = NULL;
260 if (!pfn_t_has_page(pfn)) {
261 wc->memory_map = NULL;
267 wc->memory_map = NULL;
268 pages = kvmalloc_array(p, sizeof(struct page *), GFP_KERNEL);
276 daa = dax_direct_access(wc->ssd_dev->dax_dev, i, p - i,
279 r = daa ? daa : -EINVAL;
282 if (!pfn_t_has_page(pfn)) {
286 while (daa-- && i < p) {
287 pages[i++] = pfn_t_to_page(pfn);
291 wc->memory_map = vmap(pages, p, VM_MAP, PAGE_KERNEL);
292 if (!wc->memory_map) {
297 wc->memory_vmapped = true;
302 wc->memory_map += (size_t)wc->start_sector << SECTOR_SHIFT;
303 wc->memory_map_size -= (size_t)wc->start_sector << SECTOR_SHIFT;
314 static int persistent_memory_claim(struct dm_writecache *wc)
320 static void persistent_memory_release(struct dm_writecache *wc)
322 if (wc->memory_vmapped)
323 vunmap(wc->memory_map - ((size_t)wc->start_sector << SECTOR_SHIFT));
326 static struct page *persistent_memory_page(void *addr)
328 if (is_vmalloc_addr(addr))
329 return vmalloc_to_page(addr);
331 return virt_to_page(addr);
334 static unsigned persistent_memory_page_offset(void *addr)
336 return (unsigned long)addr & (PAGE_SIZE - 1);
339 static void persistent_memory_flush_cache(void *ptr, size_t size)
341 if (is_vmalloc_addr(ptr))
342 flush_kernel_vmap_range(ptr, size);
345 static void persistent_memory_invalidate_cache(void *ptr, size_t size)
347 if (is_vmalloc_addr(ptr))
348 invalidate_kernel_vmap_range(ptr, size);
351 static struct wc_memory_superblock *sb(struct dm_writecache *wc)
353 return wc->memory_map;
356 static struct wc_memory_entry *memory_entry(struct dm_writecache *wc, struct wc_entry *e)
358 return &sb(wc)->entries[e->index];
361 static void *memory_data(struct dm_writecache *wc, struct wc_entry *e)
363 return (char *)wc->block_start + (e->index << wc->block_size_bits);
366 static sector_t cache_sector(struct dm_writecache *wc, struct wc_entry *e)
368 return wc->start_sector + wc->metadata_sectors +
369 ((sector_t)e->index << (wc->block_size_bits - SECTOR_SHIFT));
372 static uint64_t read_original_sector(struct dm_writecache *wc, struct wc_entry *e)
374 #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
375 return e->original_sector;
377 return le64_to_cpu(memory_entry(wc, e)->original_sector);
381 static uint64_t read_seq_count(struct dm_writecache *wc, struct wc_entry *e)
383 #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
386 return le64_to_cpu(memory_entry(wc, e)->seq_count);
390 static void clear_seq_count(struct dm_writecache *wc, struct wc_entry *e)
392 #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
395 pmem_assign(memory_entry(wc, e)->seq_count, cpu_to_le64(-1));
398 static void write_original_sector_seq_count(struct dm_writecache *wc, struct wc_entry *e,
399 uint64_t original_sector, uint64_t seq_count)
401 struct wc_memory_entry me;
402 #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
403 e->original_sector = original_sector;
404 e->seq_count = seq_count;
406 me.original_sector = cpu_to_le64(original_sector);
407 me.seq_count = cpu_to_le64(seq_count);
408 pmem_assign(*memory_entry(wc, e), me);
411 #define writecache_error(wc, err, msg, arg...) \
413 if (!cmpxchg(&(wc)->error, 0, err)) \
415 wake_up(&(wc)->freelist_wait); \
418 #define writecache_has_error(wc) (unlikely(READ_ONCE((wc)->error)))
420 static void writecache_flush_all_metadata(struct dm_writecache *wc)
422 if (!WC_MODE_PMEM(wc))
423 memset(wc->dirty_bitmap, -1, wc->dirty_bitmap_size);
426 static void writecache_flush_region(struct dm_writecache *wc, void *ptr, size_t size)
428 if (!WC_MODE_PMEM(wc))
429 __set_bit(((char *)ptr - (char *)wc->memory_map) / BITMAP_GRANULARITY,
433 static void writecache_disk_flush(struct dm_writecache *wc, struct dm_dev *dev);
436 struct dm_writecache *wc;
441 static void writecache_notify_io(unsigned long error, void *context)
443 struct io_notify *endio = context;
445 if (unlikely(error != 0))
446 writecache_error(endio->wc, -EIO, "error writing metadata");
447 BUG_ON(atomic_read(&endio->count) <= 0);
448 if (atomic_dec_and_test(&endio->count))
452 static void writecache_wait_for_ios(struct dm_writecache *wc, int direction)
454 wait_event(wc->bio_in_progress_wait[direction],
455 !atomic_read(&wc->bio_in_progress[direction]));
458 static void ssd_commit_flushed(struct dm_writecache *wc, bool wait_for_ios)
460 struct dm_io_region region;
461 struct dm_io_request req;
462 struct io_notify endio = {
464 COMPLETION_INITIALIZER_ONSTACK(endio.c),
467 unsigned bitmap_bits = wc->dirty_bitmap_size * 8;
472 i = find_next_bit(wc->dirty_bitmap, bitmap_bits, i);
473 if (unlikely(i == bitmap_bits))
475 j = find_next_zero_bit(wc->dirty_bitmap, bitmap_bits, i);
477 region.bdev = wc->ssd_dev->bdev;
478 region.sector = (sector_t)i * (BITMAP_GRANULARITY >> SECTOR_SHIFT);
479 region.count = (sector_t)(j - i) * (BITMAP_GRANULARITY >> SECTOR_SHIFT);
481 if (unlikely(region.sector >= wc->metadata_sectors))
483 if (unlikely(region.sector + region.count > wc->metadata_sectors))
484 region.count = wc->metadata_sectors - region.sector;
486 region.sector += wc->start_sector;
487 atomic_inc(&endio.count);
488 req.bi_op = REQ_OP_WRITE;
489 req.bi_op_flags = REQ_SYNC;
490 req.mem.type = DM_IO_VMA;
491 req.mem.ptr.vma = (char *)wc->memory_map + (size_t)i * BITMAP_GRANULARITY;
492 req.client = wc->dm_io;
493 req.notify.fn = writecache_notify_io;
494 req.notify.context = &endio;
496 /* writing via async dm-io (implied by notify.fn above) won't return an error */
497 (void) dm_io(&req, 1, ®ion, NULL);
501 writecache_notify_io(0, &endio);
502 wait_for_completion_io(&endio.c);
505 writecache_wait_for_ios(wc, WRITE);
507 writecache_disk_flush(wc, wc->ssd_dev);
509 memset(wc->dirty_bitmap, 0, wc->dirty_bitmap_size);
512 static void ssd_commit_superblock(struct dm_writecache *wc)
515 struct dm_io_region region;
516 struct dm_io_request req;
518 region.bdev = wc->ssd_dev->bdev;
520 region.count = PAGE_SIZE;
522 if (unlikely(region.sector + region.count > wc->metadata_sectors))
523 region.count = wc->metadata_sectors - region.sector;
525 region.sector += wc->start_sector;
527 req.bi_op = REQ_OP_WRITE;
528 req.bi_op_flags = REQ_SYNC | REQ_FUA;
529 req.mem.type = DM_IO_VMA;
530 req.mem.ptr.vma = (char *)wc->memory_map;
531 req.client = wc->dm_io;
532 req.notify.fn = NULL;
533 req.notify.context = NULL;
535 r = dm_io(&req, 1, ®ion, NULL);
537 writecache_error(wc, r, "error writing superblock");
540 static void writecache_commit_flushed(struct dm_writecache *wc, bool wait_for_ios)
542 if (WC_MODE_PMEM(wc))
545 ssd_commit_flushed(wc, wait_for_ios);
548 static void writecache_disk_flush(struct dm_writecache *wc, struct dm_dev *dev)
551 struct dm_io_region region;
552 struct dm_io_request req;
554 region.bdev = dev->bdev;
557 req.bi_op = REQ_OP_WRITE;
558 req.bi_op_flags = REQ_PREFLUSH;
559 req.mem.type = DM_IO_KMEM;
560 req.mem.ptr.addr = NULL;
561 req.client = wc->dm_io;
562 req.notify.fn = NULL;
564 r = dm_io(&req, 1, ®ion, NULL);
566 writecache_error(wc, r, "error flushing metadata: %d", r);
569 #define WFE_RETURN_FOLLOWING 1
570 #define WFE_LOWEST_SEQ 2
572 static struct wc_entry *writecache_find_entry(struct dm_writecache *wc,
573 uint64_t block, int flags)
576 struct rb_node *node = wc->tree.rb_node;
582 e = container_of(node, struct wc_entry, rb_node);
583 if (read_original_sector(wc, e) == block)
586 node = (read_original_sector(wc, e) >= block ?
587 e->rb_node.rb_left : e->rb_node.rb_right);
588 if (unlikely(!node)) {
589 if (!(flags & WFE_RETURN_FOLLOWING))
591 if (read_original_sector(wc, e) >= block) {
594 node = rb_next(&e->rb_node);
597 e = container_of(node, struct wc_entry, rb_node);
605 if (flags & WFE_LOWEST_SEQ)
606 node = rb_prev(&e->rb_node);
608 node = rb_next(&e->rb_node);
611 e2 = container_of(node, struct wc_entry, rb_node);
612 if (read_original_sector(wc, e2) != block)
618 static void writecache_insert_entry(struct dm_writecache *wc, struct wc_entry *ins)
621 struct rb_node **node = &wc->tree.rb_node, *parent = NULL;
624 e = container_of(*node, struct wc_entry, rb_node);
625 parent = &e->rb_node;
626 if (read_original_sector(wc, e) > read_original_sector(wc, ins))
627 node = &parent->rb_left;
629 node = &parent->rb_right;
631 rb_link_node(&ins->rb_node, parent, node);
632 rb_insert_color(&ins->rb_node, &wc->tree);
633 list_add(&ins->lru, &wc->lru);
637 static void writecache_unlink(struct dm_writecache *wc, struct wc_entry *e)
640 rb_erase(&e->rb_node, &wc->tree);
643 static void writecache_add_to_freelist(struct dm_writecache *wc, struct wc_entry *e)
645 if (WC_MODE_SORT_FREELIST(wc)) {
646 struct rb_node **node = &wc->freetree.rb_node, *parent = NULL;
647 if (unlikely(!*node))
648 wc->current_free = e;
651 if (&e->rb_node < *node)
652 node = &parent->rb_left;
654 node = &parent->rb_right;
656 rb_link_node(&e->rb_node, parent, node);
657 rb_insert_color(&e->rb_node, &wc->freetree);
659 list_add_tail(&e->lru, &wc->freelist);
664 static inline void writecache_verify_watermark(struct dm_writecache *wc)
666 if (unlikely(wc->freelist_size + wc->writeback_size <= wc->freelist_high_watermark))
667 queue_work(wc->writeback_wq, &wc->writeback_work);
670 static void writecache_max_age_timer(struct timer_list *t)
672 struct dm_writecache *wc = from_timer(wc, t, max_age_timer);
674 if (!dm_suspended(wc->ti) && !writecache_has_error(wc)) {
675 queue_work(wc->writeback_wq, &wc->writeback_work);
676 mod_timer(&wc->max_age_timer, jiffies + wc->max_age / MAX_AGE_DIV);
680 static struct wc_entry *writecache_pop_from_freelist(struct dm_writecache *wc, sector_t expected_sector)
684 if (WC_MODE_SORT_FREELIST(wc)) {
685 struct rb_node *next;
686 if (unlikely(!wc->current_free))
688 e = wc->current_free;
689 if (expected_sector != (sector_t)-1 && unlikely(cache_sector(wc, e) != expected_sector))
691 next = rb_next(&e->rb_node);
692 rb_erase(&e->rb_node, &wc->freetree);
694 next = rb_first(&wc->freetree);
695 wc->current_free = next ? container_of(next, struct wc_entry, rb_node) : NULL;
697 if (unlikely(list_empty(&wc->freelist)))
699 e = container_of(wc->freelist.next, struct wc_entry, lru);
700 if (expected_sector != (sector_t)-1 && unlikely(cache_sector(wc, e) != expected_sector))
706 writecache_verify_watermark(wc);
711 static void writecache_free_entry(struct dm_writecache *wc, struct wc_entry *e)
713 writecache_unlink(wc, e);
714 writecache_add_to_freelist(wc, e);
715 clear_seq_count(wc, e);
716 writecache_flush_region(wc, memory_entry(wc, e), sizeof(struct wc_memory_entry));
717 if (unlikely(waitqueue_active(&wc->freelist_wait)))
718 wake_up(&wc->freelist_wait);
721 static void writecache_wait_on_freelist(struct dm_writecache *wc)
725 prepare_to_wait(&wc->freelist_wait, &wait, TASK_UNINTERRUPTIBLE);
728 finish_wait(&wc->freelist_wait, &wait);
732 static void writecache_poison_lists(struct dm_writecache *wc)
735 * Catch incorrect access to these values while the device is suspended.
737 memset(&wc->tree, -1, sizeof wc->tree);
738 wc->lru.next = LIST_POISON1;
739 wc->lru.prev = LIST_POISON2;
740 wc->freelist.next = LIST_POISON1;
741 wc->freelist.prev = LIST_POISON2;
744 static void writecache_flush_entry(struct dm_writecache *wc, struct wc_entry *e)
746 writecache_flush_region(wc, memory_entry(wc, e), sizeof(struct wc_memory_entry));
747 if (WC_MODE_PMEM(wc))
748 writecache_flush_region(wc, memory_data(wc, e), wc->block_size);
751 static bool writecache_entry_is_committed(struct dm_writecache *wc, struct wc_entry *e)
753 return read_seq_count(wc, e) < wc->seq_count;
756 static void writecache_flush(struct dm_writecache *wc)
758 struct wc_entry *e, *e2;
759 bool need_flush_after_free;
761 wc->uncommitted_blocks = 0;
762 del_timer(&wc->autocommit_timer);
764 if (list_empty(&wc->lru))
767 e = container_of(wc->lru.next, struct wc_entry, lru);
768 if (writecache_entry_is_committed(wc, e)) {
769 if (wc->overwrote_committed) {
770 writecache_wait_for_ios(wc, WRITE);
771 writecache_disk_flush(wc, wc->ssd_dev);
772 wc->overwrote_committed = false;
777 writecache_flush_entry(wc, e);
778 if (unlikely(e->lru.next == &wc->lru))
780 e2 = container_of(e->lru.next, struct wc_entry, lru);
781 if (writecache_entry_is_committed(wc, e2))
786 writecache_commit_flushed(wc, true);
789 pmem_assign(sb(wc)->seq_count, cpu_to_le64(wc->seq_count));
790 if (WC_MODE_PMEM(wc))
791 writecache_commit_flushed(wc, false);
793 ssd_commit_superblock(wc);
795 wc->overwrote_committed = false;
797 need_flush_after_free = false;
799 /* Free another committed entry with lower seq-count */
800 struct rb_node *rb_node = rb_prev(&e->rb_node);
803 e2 = container_of(rb_node, struct wc_entry, rb_node);
804 if (read_original_sector(wc, e2) == read_original_sector(wc, e) &&
805 likely(!e2->write_in_progress)) {
806 writecache_free_entry(wc, e2);
807 need_flush_after_free = true;
810 if (unlikely(e->lru.prev == &wc->lru))
812 e = container_of(e->lru.prev, struct wc_entry, lru);
816 if (need_flush_after_free)
817 writecache_commit_flushed(wc, false);
820 static void writecache_flush_work(struct work_struct *work)
822 struct dm_writecache *wc = container_of(work, struct dm_writecache, flush_work);
825 writecache_flush(wc);
829 static void writecache_autocommit_timer(struct timer_list *t)
831 struct dm_writecache *wc = from_timer(wc, t, autocommit_timer);
832 if (!writecache_has_error(wc))
833 queue_work(wc->writeback_wq, &wc->flush_work);
836 static void writecache_schedule_autocommit(struct dm_writecache *wc)
838 if (!timer_pending(&wc->autocommit_timer))
839 mod_timer(&wc->autocommit_timer, jiffies + wc->autocommit_jiffies);
842 static void writecache_discard(struct dm_writecache *wc, sector_t start, sector_t end)
845 bool discarded_something = false;
847 e = writecache_find_entry(wc, start, WFE_RETURN_FOLLOWING | WFE_LOWEST_SEQ);
851 while (read_original_sector(wc, e) < end) {
852 struct rb_node *node = rb_next(&e->rb_node);
854 if (likely(!e->write_in_progress)) {
855 if (!discarded_something) {
856 writecache_wait_for_ios(wc, READ);
857 writecache_wait_for_ios(wc, WRITE);
858 discarded_something = true;
860 writecache_free_entry(wc, e);
866 e = container_of(node, struct wc_entry, rb_node);
869 if (discarded_something)
870 writecache_commit_flushed(wc, false);
873 static bool writecache_wait_for_writeback(struct dm_writecache *wc)
875 if (wc->writeback_size) {
876 writecache_wait_on_freelist(wc);
882 static void writecache_suspend(struct dm_target *ti)
884 struct dm_writecache *wc = ti->private;
885 bool flush_on_suspend;
887 del_timer_sync(&wc->autocommit_timer);
888 del_timer_sync(&wc->max_age_timer);
891 writecache_flush(wc);
892 flush_on_suspend = wc->flush_on_suspend;
893 if (flush_on_suspend) {
894 wc->flush_on_suspend = false;
896 queue_work(wc->writeback_wq, &wc->writeback_work);
900 drain_workqueue(wc->writeback_wq);
903 if (flush_on_suspend)
905 while (writecache_wait_for_writeback(wc));
907 if (WC_MODE_PMEM(wc))
908 persistent_memory_flush_cache(wc->memory_map, wc->memory_map_size);
910 writecache_poison_lists(wc);
915 static int writecache_alloc_entries(struct dm_writecache *wc)
921 wc->entries = vmalloc(array_size(sizeof(struct wc_entry), wc->n_blocks));
924 for (b = 0; b < wc->n_blocks; b++) {
925 struct wc_entry *e = &wc->entries[b];
927 e->write_in_progress = false;
934 static int writecache_read_metadata(struct dm_writecache *wc, sector_t n_sectors)
936 struct dm_io_region region;
937 struct dm_io_request req;
939 region.bdev = wc->ssd_dev->bdev;
940 region.sector = wc->start_sector;
941 region.count = n_sectors;
942 req.bi_op = REQ_OP_READ;
943 req.bi_op_flags = REQ_SYNC;
944 req.mem.type = DM_IO_VMA;
945 req.mem.ptr.vma = (char *)wc->memory_map;
946 req.client = wc->dm_io;
947 req.notify.fn = NULL;
949 return dm_io(&req, 1, ®ion, NULL);
952 static void writecache_resume(struct dm_target *ti)
954 struct dm_writecache *wc = ti->private;
956 bool need_flush = false;
962 if (WC_MODE_PMEM(wc)) {
963 persistent_memory_invalidate_cache(wc->memory_map, wc->memory_map_size);
965 r = writecache_read_metadata(wc, wc->metadata_sectors);
967 size_t sb_entries_offset;
968 writecache_error(wc, r, "unable to read metadata: %d", r);
969 sb_entries_offset = offsetof(struct wc_memory_superblock, entries);
970 memset((char *)wc->memory_map + sb_entries_offset, -1,
971 (wc->metadata_sectors << SECTOR_SHIFT) - sb_entries_offset);
976 INIT_LIST_HEAD(&wc->lru);
977 if (WC_MODE_SORT_FREELIST(wc)) {
978 wc->freetree = RB_ROOT;
979 wc->current_free = NULL;
981 INIT_LIST_HEAD(&wc->freelist);
983 wc->freelist_size = 0;
985 r = memcpy_mcsafe(&sb_seq_count, &sb(wc)->seq_count, sizeof(uint64_t));
987 writecache_error(wc, r, "hardware memory error when reading superblock: %d", r);
988 sb_seq_count = cpu_to_le64(0);
990 wc->seq_count = le64_to_cpu(sb_seq_count);
992 #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
993 for (b = 0; b < wc->n_blocks; b++) {
994 struct wc_entry *e = &wc->entries[b];
995 struct wc_memory_entry wme;
996 if (writecache_has_error(wc)) {
997 e->original_sector = -1;
1001 r = memcpy_mcsafe(&wme, memory_entry(wc, e), sizeof(struct wc_memory_entry));
1003 writecache_error(wc, r, "hardware memory error when reading metadata entry %lu: %d",
1004 (unsigned long)b, r);
1005 e->original_sector = -1;
1008 e->original_sector = le64_to_cpu(wme.original_sector);
1009 e->seq_count = le64_to_cpu(wme.seq_count);
1014 for (b = 0; b < wc->n_blocks; b++) {
1015 struct wc_entry *e = &wc->entries[b];
1016 if (!writecache_entry_is_committed(wc, e)) {
1017 if (read_seq_count(wc, e) != -1) {
1019 clear_seq_count(wc, e);
1022 writecache_add_to_freelist(wc, e);
1024 struct wc_entry *old;
1026 old = writecache_find_entry(wc, read_original_sector(wc, e), 0);
1028 writecache_insert_entry(wc, e);
1030 if (read_seq_count(wc, old) == read_seq_count(wc, e)) {
1031 writecache_error(wc, -EINVAL,
1032 "two identical entries, position %llu, sector %llu, sequence %llu",
1033 (unsigned long long)b, (unsigned long long)read_original_sector(wc, e),
1034 (unsigned long long)read_seq_count(wc, e));
1036 if (read_seq_count(wc, old) > read_seq_count(wc, e)) {
1039 writecache_free_entry(wc, old);
1040 writecache_insert_entry(wc, e);
1049 writecache_flush_all_metadata(wc);
1050 writecache_commit_flushed(wc, false);
1053 writecache_verify_watermark(wc);
1055 if (wc->max_age != MAX_AGE_UNSPECIFIED)
1056 mod_timer(&wc->max_age_timer, jiffies + wc->max_age / MAX_AGE_DIV);
1061 static int process_flush_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
1067 if (dm_suspended(wc->ti)) {
1071 if (writecache_has_error(wc)) {
1076 writecache_flush(wc);
1077 wc->writeback_all++;
1078 queue_work(wc->writeback_wq, &wc->writeback_work);
1081 flush_workqueue(wc->writeback_wq);
1084 wc->writeback_all--;
1085 if (writecache_has_error(wc)) {
1094 static int process_flush_on_suspend_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
1100 wc->flush_on_suspend = true;
1106 static void activate_cleaner(struct dm_writecache *wc)
1108 wc->flush_on_suspend = true;
1110 wc->freelist_high_watermark = wc->n_blocks;
1111 wc->freelist_low_watermark = wc->n_blocks;
1114 static int process_cleaner_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
1120 activate_cleaner(wc);
1121 if (!dm_suspended(wc->ti))
1122 writecache_verify_watermark(wc);
1128 static int writecache_message(struct dm_target *ti, unsigned argc, char **argv,
1129 char *result, unsigned maxlen)
1132 struct dm_writecache *wc = ti->private;
1134 if (!strcasecmp(argv[0], "flush"))
1135 r = process_flush_mesg(argc, argv, wc);
1136 else if (!strcasecmp(argv[0], "flush_on_suspend"))
1137 r = process_flush_on_suspend_mesg(argc, argv, wc);
1138 else if (!strcasecmp(argv[0], "cleaner"))
1139 r = process_cleaner_mesg(argc, argv, wc);
1141 DMERR("unrecognised message received: %s", argv[0]);
1146 static void bio_copy_block(struct dm_writecache *wc, struct bio *bio, void *data)
1149 unsigned long flags;
1151 int rw = bio_data_dir(bio);
1152 unsigned remaining_size = wc->block_size;
1155 struct bio_vec bv = bio_iter_iovec(bio, bio->bi_iter);
1156 buf = bvec_kmap_irq(&bv, &flags);
1158 if (unlikely(size > remaining_size))
1159 size = remaining_size;
1163 r = memcpy_mcsafe(buf, data, size);
1164 flush_dcache_page(bio_page(bio));
1166 writecache_error(wc, r, "hardware memory error when reading data: %d", r);
1167 bio->bi_status = BLK_STS_IOERR;
1170 flush_dcache_page(bio_page(bio));
1171 memcpy_flushcache(data, buf, size);
1174 bvec_kunmap_irq(buf, &flags);
1176 data = (char *)data + size;
1177 remaining_size -= size;
1178 bio_advance(bio, size);
1179 } while (unlikely(remaining_size));
1182 static int writecache_flush_thread(void *data)
1184 struct dm_writecache *wc = data;
1190 bio = bio_list_pop(&wc->flush_list);
1192 set_current_state(TASK_INTERRUPTIBLE);
1195 if (unlikely(kthread_should_stop())) {
1196 set_current_state(TASK_RUNNING);
1204 if (bio_op(bio) == REQ_OP_DISCARD) {
1205 writecache_discard(wc, bio->bi_iter.bi_sector,
1206 bio_end_sector(bio));
1208 bio_set_dev(bio, wc->dev->bdev);
1209 generic_make_request(bio);
1211 writecache_flush(wc);
1213 if (writecache_has_error(wc))
1214 bio->bi_status = BLK_STS_IOERR;
1222 static void writecache_offload_bio(struct dm_writecache *wc, struct bio *bio)
1224 if (bio_list_empty(&wc->flush_list))
1225 wake_up_process(wc->flush_thread);
1226 bio_list_add(&wc->flush_list, bio);
1229 static int writecache_map(struct dm_target *ti, struct bio *bio)
1232 struct dm_writecache *wc = ti->private;
1234 bio->bi_private = NULL;
1238 if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
1239 if (writecache_has_error(wc))
1241 if (WC_MODE_PMEM(wc)) {
1242 writecache_flush(wc);
1243 if (writecache_has_error(wc))
1247 writecache_offload_bio(wc, bio);
1252 bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
1254 if (unlikely((((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) &
1255 (wc->block_size / 512 - 1)) != 0)) {
1256 DMERR("I/O is not aligned, sector %llu, size %u, block size %u",
1257 (unsigned long long)bio->bi_iter.bi_sector,
1258 bio->bi_iter.bi_size, wc->block_size);
1262 if (unlikely(bio_op(bio) == REQ_OP_DISCARD)) {
1263 if (writecache_has_error(wc))
1265 if (WC_MODE_PMEM(wc)) {
1266 writecache_discard(wc, bio->bi_iter.bi_sector, bio_end_sector(bio));
1267 goto unlock_remap_origin;
1269 writecache_offload_bio(wc, bio);
1274 if (bio_data_dir(bio) == READ) {
1276 e = writecache_find_entry(wc, bio->bi_iter.bi_sector, WFE_RETURN_FOLLOWING);
1277 if (e && read_original_sector(wc, e) == bio->bi_iter.bi_sector) {
1278 if (WC_MODE_PMEM(wc)) {
1279 bio_copy_block(wc, bio, memory_data(wc, e));
1280 if (bio->bi_iter.bi_size)
1281 goto read_next_block;
1284 dm_accept_partial_bio(bio, wc->block_size >> SECTOR_SHIFT);
1285 bio_set_dev(bio, wc->ssd_dev->bdev);
1286 bio->bi_iter.bi_sector = cache_sector(wc, e);
1287 if (!writecache_entry_is_committed(wc, e))
1288 writecache_wait_for_ios(wc, WRITE);
1293 sector_t next_boundary =
1294 read_original_sector(wc, e) - bio->bi_iter.bi_sector;
1295 if (next_boundary < bio->bi_iter.bi_size >> SECTOR_SHIFT) {
1296 dm_accept_partial_bio(bio, next_boundary);
1299 goto unlock_remap_origin;
1303 bool found_entry = false;
1304 if (writecache_has_error(wc))
1306 e = writecache_find_entry(wc, bio->bi_iter.bi_sector, 0);
1308 if (!writecache_entry_is_committed(wc, e))
1310 if (!WC_MODE_PMEM(wc) && !e->write_in_progress) {
1311 wc->overwrote_committed = true;
1316 if (unlikely(wc->cleaner))
1319 e = writecache_pop_from_freelist(wc, (sector_t)-1);
1323 e = writecache_find_entry(wc, bio->bi_iter.bi_sector, WFE_RETURN_FOLLOWING);
1325 sector_t next_boundary = read_original_sector(wc, e) - bio->bi_iter.bi_sector;
1326 BUG_ON(!next_boundary);
1327 if (next_boundary < bio->bi_iter.bi_size >> SECTOR_SHIFT) {
1328 dm_accept_partial_bio(bio, next_boundary);
1331 goto unlock_remap_origin;
1333 writecache_wait_on_freelist(wc);
1336 write_original_sector_seq_count(wc, e, bio->bi_iter.bi_sector, wc->seq_count);
1337 writecache_insert_entry(wc, e);
1338 wc->uncommitted_blocks++;
1340 if (WC_MODE_PMEM(wc)) {
1341 bio_copy_block(wc, bio, memory_data(wc, e));
1343 unsigned bio_size = wc->block_size;
1344 sector_t start_cache_sec = cache_sector(wc, e);
1345 sector_t current_cache_sec = start_cache_sec + (bio_size >> SECTOR_SHIFT);
1347 while (bio_size < bio->bi_iter.bi_size) {
1348 struct wc_entry *f = writecache_pop_from_freelist(wc, current_cache_sec);
1351 write_original_sector_seq_count(wc, f, bio->bi_iter.bi_sector +
1352 (bio_size >> SECTOR_SHIFT), wc->seq_count);
1353 writecache_insert_entry(wc, f);
1354 wc->uncommitted_blocks++;
1355 bio_size += wc->block_size;
1356 current_cache_sec += wc->block_size >> SECTOR_SHIFT;
1359 bio_set_dev(bio, wc->ssd_dev->bdev);
1360 bio->bi_iter.bi_sector = start_cache_sec;
1361 dm_accept_partial_bio(bio, bio_size >> SECTOR_SHIFT);
1363 if (unlikely(wc->uncommitted_blocks >= wc->autocommit_blocks)) {
1364 wc->uncommitted_blocks = 0;
1365 queue_work(wc->writeback_wq, &wc->flush_work);
1367 writecache_schedule_autocommit(wc);
1371 } while (bio->bi_iter.bi_size);
1373 if (unlikely(bio->bi_opf & REQ_FUA ||
1374 wc->uncommitted_blocks >= wc->autocommit_blocks))
1375 writecache_flush(wc);
1377 writecache_schedule_autocommit(wc);
1381 unlock_remap_origin:
1382 bio_set_dev(bio, wc->dev->bdev);
1384 return DM_MAPIO_REMAPPED;
1387 /* make sure that writecache_end_io decrements bio_in_progress: */
1388 bio->bi_private = (void *)1;
1389 atomic_inc(&wc->bio_in_progress[bio_data_dir(bio)]);
1391 return DM_MAPIO_REMAPPED;
1396 return DM_MAPIO_SUBMITTED;
1400 return DM_MAPIO_SUBMITTED;
1405 return DM_MAPIO_SUBMITTED;
1408 static int writecache_end_io(struct dm_target *ti, struct bio *bio, blk_status_t *status)
1410 struct dm_writecache *wc = ti->private;
1412 if (bio->bi_private != NULL) {
1413 int dir = bio_data_dir(bio);
1414 if (atomic_dec_and_test(&wc->bio_in_progress[dir]))
1415 if (unlikely(waitqueue_active(&wc->bio_in_progress_wait[dir])))
1416 wake_up(&wc->bio_in_progress_wait[dir]);
1421 static int writecache_iterate_devices(struct dm_target *ti,
1422 iterate_devices_callout_fn fn, void *data)
1424 struct dm_writecache *wc = ti->private;
1426 return fn(ti, wc->dev, 0, ti->len, data);
1429 static void writecache_io_hints(struct dm_target *ti, struct queue_limits *limits)
1431 struct dm_writecache *wc = ti->private;
1433 if (limits->logical_block_size < wc->block_size)
1434 limits->logical_block_size = wc->block_size;
1436 if (limits->physical_block_size < wc->block_size)
1437 limits->physical_block_size = wc->block_size;
1439 if (limits->io_min < wc->block_size)
1440 limits->io_min = wc->block_size;
1444 static void writecache_writeback_endio(struct bio *bio)
1446 struct writeback_struct *wb = container_of(bio, struct writeback_struct, bio);
1447 struct dm_writecache *wc = wb->wc;
1448 unsigned long flags;
1450 raw_spin_lock_irqsave(&wc->endio_list_lock, flags);
1451 if (unlikely(list_empty(&wc->endio_list)))
1452 wake_up_process(wc->endio_thread);
1453 list_add_tail(&wb->endio_entry, &wc->endio_list);
1454 raw_spin_unlock_irqrestore(&wc->endio_list_lock, flags);
1457 static void writecache_copy_endio(int read_err, unsigned long write_err, void *ptr)
1459 struct copy_struct *c = ptr;
1460 struct dm_writecache *wc = c->wc;
1462 c->error = likely(!(read_err | write_err)) ? 0 : -EIO;
1464 raw_spin_lock_irq(&wc->endio_list_lock);
1465 if (unlikely(list_empty(&wc->endio_list)))
1466 wake_up_process(wc->endio_thread);
1467 list_add_tail(&c->endio_entry, &wc->endio_list);
1468 raw_spin_unlock_irq(&wc->endio_list_lock);
1471 static void __writecache_endio_pmem(struct dm_writecache *wc, struct list_head *list)
1474 struct writeback_struct *wb;
1476 unsigned long n_walked = 0;
1479 wb = list_entry(list->next, struct writeback_struct, endio_entry);
1480 list_del(&wb->endio_entry);
1482 if (unlikely(wb->bio.bi_status != BLK_STS_OK))
1483 writecache_error(wc, blk_status_to_errno(wb->bio.bi_status),
1484 "write error %d", wb->bio.bi_status);
1488 BUG_ON(!e->write_in_progress);
1489 e->write_in_progress = false;
1490 INIT_LIST_HEAD(&e->lru);
1491 if (!writecache_has_error(wc))
1492 writecache_free_entry(wc, e);
1493 BUG_ON(!wc->writeback_size);
1494 wc->writeback_size--;
1496 if (unlikely(n_walked >= ENDIO_LATENCY)) {
1497 writecache_commit_flushed(wc, false);
1502 } while (++i < wb->wc_list_n);
1504 if (wb->wc_list != wb->wc_list_inline)
1507 } while (!list_empty(list));
1510 static void __writecache_endio_ssd(struct dm_writecache *wc, struct list_head *list)
1512 struct copy_struct *c;
1516 c = list_entry(list->next, struct copy_struct, endio_entry);
1517 list_del(&c->endio_entry);
1519 if (unlikely(c->error))
1520 writecache_error(wc, c->error, "copy error");
1524 BUG_ON(!e->write_in_progress);
1525 e->write_in_progress = false;
1526 INIT_LIST_HEAD(&e->lru);
1527 if (!writecache_has_error(wc))
1528 writecache_free_entry(wc, e);
1530 BUG_ON(!wc->writeback_size);
1531 wc->writeback_size--;
1533 } while (--c->n_entries);
1534 mempool_free(c, &wc->copy_pool);
1535 } while (!list_empty(list));
1538 static int writecache_endio_thread(void *data)
1540 struct dm_writecache *wc = data;
1543 struct list_head list;
1545 raw_spin_lock_irq(&wc->endio_list_lock);
1546 if (!list_empty(&wc->endio_list))
1548 set_current_state(TASK_INTERRUPTIBLE);
1549 raw_spin_unlock_irq(&wc->endio_list_lock);
1551 if (unlikely(kthread_should_stop())) {
1552 set_current_state(TASK_RUNNING);
1561 list = wc->endio_list;
1562 list.next->prev = list.prev->next = &list;
1563 INIT_LIST_HEAD(&wc->endio_list);
1564 raw_spin_unlock_irq(&wc->endio_list_lock);
1566 if (!WC_MODE_FUA(wc))
1567 writecache_disk_flush(wc, wc->dev);
1571 if (WC_MODE_PMEM(wc)) {
1572 __writecache_endio_pmem(wc, &list);
1574 __writecache_endio_ssd(wc, &list);
1575 writecache_wait_for_ios(wc, READ);
1578 writecache_commit_flushed(wc, false);
1586 static bool wc_add_block(struct writeback_struct *wb, struct wc_entry *e, gfp_t gfp)
1588 struct dm_writecache *wc = wb->wc;
1589 unsigned block_size = wc->block_size;
1590 void *address = memory_data(wc, e);
1592 persistent_memory_flush_cache(address, block_size);
1593 return bio_add_page(&wb->bio, persistent_memory_page(address),
1594 block_size, persistent_memory_page_offset(address)) != 0;
1597 struct writeback_list {
1598 struct list_head list;
1602 static void __writeback_throttle(struct dm_writecache *wc, struct writeback_list *wbl)
1604 if (unlikely(wc->max_writeback_jobs)) {
1605 if (READ_ONCE(wc->writeback_size) - wbl->size >= wc->max_writeback_jobs) {
1607 while (wc->writeback_size - wbl->size >= wc->max_writeback_jobs)
1608 writecache_wait_on_freelist(wc);
1615 static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeback_list *wbl)
1617 struct wc_entry *e, *f;
1619 struct writeback_struct *wb;
1624 e = container_of(wbl->list.prev, struct wc_entry, lru);
1627 max_pages = e->wc_list_contiguous;
1629 bio = bio_alloc_bioset(GFP_NOIO, max_pages, &wc->bio_set);
1630 wb = container_of(bio, struct writeback_struct, bio);
1632 bio->bi_end_io = writecache_writeback_endio;
1633 bio_set_dev(bio, wc->dev->bdev);
1634 bio->bi_iter.bi_sector = read_original_sector(wc, e);
1635 if (max_pages <= WB_LIST_INLINE ||
1636 unlikely(!(wb->wc_list = kmalloc_array(max_pages, sizeof(struct wc_entry *),
1637 GFP_NOIO | __GFP_NORETRY |
1638 __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
1639 wb->wc_list = wb->wc_list_inline;
1640 max_pages = WB_LIST_INLINE;
1643 BUG_ON(!wc_add_block(wb, e, GFP_NOIO));
1648 while (wbl->size && wb->wc_list_n < max_pages) {
1649 f = container_of(wbl->list.prev, struct wc_entry, lru);
1650 if (read_original_sector(wc, f) !=
1651 read_original_sector(wc, e) + (wc->block_size >> SECTOR_SHIFT))
1653 if (!wc_add_block(wb, f, GFP_NOWAIT | __GFP_NOWARN))
1657 wb->wc_list[wb->wc_list_n++] = f;
1660 bio_set_op_attrs(bio, REQ_OP_WRITE, WC_MODE_FUA(wc) * REQ_FUA);
1661 if (writecache_has_error(wc)) {
1662 bio->bi_status = BLK_STS_IOERR;
1668 __writeback_throttle(wc, wbl);
1672 static void __writecache_writeback_ssd(struct dm_writecache *wc, struct writeback_list *wbl)
1674 struct wc_entry *e, *f;
1675 struct dm_io_region from, to;
1676 struct copy_struct *c;
1682 e = container_of(wbl->list.prev, struct wc_entry, lru);
1685 n_sectors = e->wc_list_contiguous << (wc->block_size_bits - SECTOR_SHIFT);
1687 from.bdev = wc->ssd_dev->bdev;
1688 from.sector = cache_sector(wc, e);
1689 from.count = n_sectors;
1690 to.bdev = wc->dev->bdev;
1691 to.sector = read_original_sector(wc, e);
1692 to.count = n_sectors;
1694 c = mempool_alloc(&wc->copy_pool, GFP_NOIO);
1697 c->n_entries = e->wc_list_contiguous;
1699 while ((n_sectors -= wc->block_size >> SECTOR_SHIFT)) {
1701 f = container_of(wbl->list.prev, struct wc_entry, lru);
1707 dm_kcopyd_copy(wc->dm_kcopyd, &from, 1, &to, 0, writecache_copy_endio, c);
1709 __writeback_throttle(wc, wbl);
1713 static void writecache_writeback(struct work_struct *work)
1715 struct dm_writecache *wc = container_of(work, struct dm_writecache, writeback_work);
1716 struct blk_plug plug;
1717 struct wc_entry *f, *uninitialized_var(g), *e = NULL;
1718 struct rb_node *node, *next_node;
1719 struct list_head skipped;
1720 struct writeback_list wbl;
1721 unsigned long n_walked;
1725 if (writecache_has_error(wc)) {
1730 if (unlikely(wc->writeback_all)) {
1731 if (writecache_wait_for_writeback(wc))
1735 if (wc->overwrote_committed) {
1736 writecache_wait_for_ios(wc, WRITE);
1740 INIT_LIST_HEAD(&skipped);
1741 INIT_LIST_HEAD(&wbl.list);
1743 while (!list_empty(&wc->lru) &&
1744 (wc->writeback_all ||
1745 wc->freelist_size + wc->writeback_size <= wc->freelist_low_watermark ||
1746 (jiffies - container_of(wc->lru.prev, struct wc_entry, lru)->age >=
1747 wc->max_age - wc->max_age / MAX_AGE_DIV))) {
1750 if (unlikely(n_walked > WRITEBACK_LATENCY) &&
1751 likely(!wc->writeback_all) && likely(!dm_suspended(wc->ti))) {
1752 queue_work(wc->writeback_wq, &wc->writeback_work);
1756 if (unlikely(wc->writeback_all)) {
1758 writecache_flush(wc);
1759 e = container_of(rb_first(&wc->tree), struct wc_entry, rb_node);
1763 e = container_of(wc->lru.prev, struct wc_entry, lru);
1764 BUG_ON(e->write_in_progress);
1765 if (unlikely(!writecache_entry_is_committed(wc, e))) {
1766 writecache_flush(wc);
1768 node = rb_prev(&e->rb_node);
1770 f = container_of(node, struct wc_entry, rb_node);
1771 if (unlikely(read_original_sector(wc, f) ==
1772 read_original_sector(wc, e))) {
1773 BUG_ON(!f->write_in_progress);
1775 list_add(&e->lru, &skipped);
1780 wc->writeback_size++;
1782 list_add(&e->lru, &wbl.list);
1784 e->write_in_progress = true;
1785 e->wc_list_contiguous = 1;
1790 next_node = rb_next(&f->rb_node);
1791 if (unlikely(!next_node))
1793 g = container_of(next_node, struct wc_entry, rb_node);
1794 if (unlikely(read_original_sector(wc, g) ==
1795 read_original_sector(wc, f))) {
1799 if (read_original_sector(wc, g) !=
1800 read_original_sector(wc, f) + (wc->block_size >> SECTOR_SHIFT))
1802 if (unlikely(g->write_in_progress))
1804 if (unlikely(!writecache_entry_is_committed(wc, g)))
1807 if (!WC_MODE_PMEM(wc)) {
1813 //if (unlikely(n_walked > WRITEBACK_LATENCY) && likely(!wc->writeback_all))
1816 wc->writeback_size++;
1818 list_add(&g->lru, &wbl.list);
1820 g->write_in_progress = true;
1821 g->wc_list_contiguous = BIO_MAX_PAGES;
1823 e->wc_list_contiguous++;
1824 if (unlikely(e->wc_list_contiguous == BIO_MAX_PAGES)) {
1825 if (unlikely(wc->writeback_all)) {
1826 next_node = rb_next(&f->rb_node);
1827 if (likely(next_node))
1828 g = container_of(next_node, struct wc_entry, rb_node);
1836 if (!list_empty(&skipped)) {
1837 list_splice_tail(&skipped, &wc->lru);
1839 * If we didn't do any progress, we must wait until some
1840 * writeback finishes to avoid burning CPU in a loop
1842 if (unlikely(!wbl.size))
1843 writecache_wait_for_writeback(wc);
1848 blk_start_plug(&plug);
1850 if (WC_MODE_PMEM(wc))
1851 __writecache_writeback_pmem(wc, &wbl);
1853 __writecache_writeback_ssd(wc, &wbl);
1855 blk_finish_plug(&plug);
1857 if (unlikely(wc->writeback_all)) {
1859 while (writecache_wait_for_writeback(wc));
1864 static int calculate_memory_size(uint64_t device_size, unsigned block_size,
1865 size_t *n_blocks_p, size_t *n_metadata_blocks_p)
1867 uint64_t n_blocks, offset;
1870 n_blocks = device_size;
1871 do_div(n_blocks, block_size + sizeof(struct wc_memory_entry));
1876 /* Verify the following entries[n_blocks] won't overflow */
1877 if (n_blocks >= ((size_t)-sizeof(struct wc_memory_superblock) /
1878 sizeof(struct wc_memory_entry)))
1880 offset = offsetof(struct wc_memory_superblock, entries[n_blocks]);
1881 offset = (offset + block_size - 1) & ~(uint64_t)(block_size - 1);
1882 if (offset + n_blocks * block_size <= device_size)
1887 /* check if the bit field overflows */
1889 if (e.index != n_blocks)
1893 *n_blocks_p = n_blocks;
1894 if (n_metadata_blocks_p)
1895 *n_metadata_blocks_p = offset >> __ffs(block_size);
1899 static int init_memory(struct dm_writecache *wc)
1904 r = calculate_memory_size(wc->memory_map_size, wc->block_size, &wc->n_blocks, NULL);
1908 r = writecache_alloc_entries(wc);
1912 for (b = 0; b < ARRAY_SIZE(sb(wc)->padding); b++)
1913 pmem_assign(sb(wc)->padding[b], cpu_to_le64(0));
1914 pmem_assign(sb(wc)->version, cpu_to_le32(MEMORY_SUPERBLOCK_VERSION));
1915 pmem_assign(sb(wc)->block_size, cpu_to_le32(wc->block_size));
1916 pmem_assign(sb(wc)->n_blocks, cpu_to_le64(wc->n_blocks));
1917 pmem_assign(sb(wc)->seq_count, cpu_to_le64(0));
1919 for (b = 0; b < wc->n_blocks; b++) {
1920 write_original_sector_seq_count(wc, &wc->entries[b], -1, -1);
1924 writecache_flush_all_metadata(wc);
1925 writecache_commit_flushed(wc, false);
1926 pmem_assign(sb(wc)->magic, cpu_to_le32(MEMORY_SUPERBLOCK_MAGIC));
1927 writecache_flush_region(wc, &sb(wc)->magic, sizeof sb(wc)->magic);
1928 writecache_commit_flushed(wc, false);
1933 static void writecache_dtr(struct dm_target *ti)
1935 struct dm_writecache *wc = ti->private;
1940 if (wc->endio_thread)
1941 kthread_stop(wc->endio_thread);
1943 if (wc->flush_thread)
1944 kthread_stop(wc->flush_thread);
1946 bioset_exit(&wc->bio_set);
1948 mempool_exit(&wc->copy_pool);
1950 if (wc->writeback_wq)
1951 destroy_workqueue(wc->writeback_wq);
1954 dm_put_device(ti, wc->dev);
1957 dm_put_device(ti, wc->ssd_dev);
1962 if (wc->memory_map) {
1963 if (WC_MODE_PMEM(wc))
1964 persistent_memory_release(wc);
1966 vfree(wc->memory_map);
1970 dm_kcopyd_client_destroy(wc->dm_kcopyd);
1973 dm_io_client_destroy(wc->dm_io);
1975 if (wc->dirty_bitmap)
1976 vfree(wc->dirty_bitmap);
1981 static int writecache_ctr(struct dm_target *ti, unsigned argc, char **argv)
1983 struct dm_writecache *wc;
1984 struct dm_arg_set as;
1986 unsigned opt_params;
1987 size_t offset, data_size;
1990 int high_wm_percent = HIGH_WATERMARK;
1991 int low_wm_percent = LOW_WATERMARK;
1993 struct wc_memory_superblock s;
1995 static struct dm_arg _args[] = {
1996 {0, 10, "Invalid number of feature args"},
2002 wc = kzalloc(sizeof(struct dm_writecache), GFP_KERNEL);
2004 ti->error = "Cannot allocate writecache structure";
2011 mutex_init(&wc->lock);
2012 wc->max_age = MAX_AGE_UNSPECIFIED;
2013 writecache_poison_lists(wc);
2014 init_waitqueue_head(&wc->freelist_wait);
2015 timer_setup(&wc->autocommit_timer, writecache_autocommit_timer, 0);
2016 timer_setup(&wc->max_age_timer, writecache_max_age_timer, 0);
2018 for (i = 0; i < 2; i++) {
2019 atomic_set(&wc->bio_in_progress[i], 0);
2020 init_waitqueue_head(&wc->bio_in_progress_wait[i]);
2023 wc->dm_io = dm_io_client_create();
2024 if (IS_ERR(wc->dm_io)) {
2025 r = PTR_ERR(wc->dm_io);
2026 ti->error = "Unable to allocate dm-io client";
2031 wc->writeback_wq = alloc_workqueue("writecache-writeback", WQ_MEM_RECLAIM, 1);
2032 if (!wc->writeback_wq) {
2034 ti->error = "Could not allocate writeback workqueue";
2037 INIT_WORK(&wc->writeback_work, writecache_writeback);
2038 INIT_WORK(&wc->flush_work, writecache_flush_work);
2040 raw_spin_lock_init(&wc->endio_list_lock);
2041 INIT_LIST_HEAD(&wc->endio_list);
2042 wc->endio_thread = kthread_create(writecache_endio_thread, wc, "writecache_endio");
2043 if (IS_ERR(wc->endio_thread)) {
2044 r = PTR_ERR(wc->endio_thread);
2045 wc->endio_thread = NULL;
2046 ti->error = "Couldn't spawn endio thread";
2049 wake_up_process(wc->endio_thread);
2052 * Parse the mode (pmem or ssd)
2054 string = dm_shift_arg(&as);
2058 if (!strcasecmp(string, "s")) {
2059 wc->pmem_mode = false;
2060 } else if (!strcasecmp(string, "p")) {
2061 #ifdef DM_WRITECACHE_HAS_PMEM
2062 wc->pmem_mode = true;
2063 wc->writeback_fua = true;
2066 * If the architecture doesn't support persistent memory or
2067 * the kernel doesn't support any DAX drivers, this driver can
2068 * only be used in SSD-only mode.
2071 ti->error = "Persistent memory or DAX not supported on this system";
2078 if (WC_MODE_PMEM(wc)) {
2079 r = bioset_init(&wc->bio_set, BIO_POOL_SIZE,
2080 offsetof(struct writeback_struct, bio),
2083 ti->error = "Could not allocate bio set";
2087 r = mempool_init_kmalloc_pool(&wc->copy_pool, 1, sizeof(struct copy_struct));
2089 ti->error = "Could not allocate mempool";
2095 * Parse the origin data device
2097 string = dm_shift_arg(&as);
2100 r = dm_get_device(ti, string, dm_table_get_mode(ti->table), &wc->dev);
2102 ti->error = "Origin data device lookup failed";
2107 * Parse cache data device (be it pmem or ssd)
2109 string = dm_shift_arg(&as);
2113 r = dm_get_device(ti, string, dm_table_get_mode(ti->table), &wc->ssd_dev);
2115 ti->error = "Cache data device lookup failed";
2118 wc->memory_map_size = i_size_read(wc->ssd_dev->bdev->bd_inode);
2121 * Parse the cache block size
2123 string = dm_shift_arg(&as);
2126 if (sscanf(string, "%u%c", &wc->block_size, &dummy) != 1 ||
2127 wc->block_size < 512 || wc->block_size > PAGE_SIZE ||
2128 (wc->block_size & (wc->block_size - 1))) {
2130 ti->error = "Invalid block size";
2133 if (wc->block_size < bdev_logical_block_size(wc->dev->bdev) ||
2134 wc->block_size < bdev_logical_block_size(wc->ssd_dev->bdev)) {
2136 ti->error = "Block size is smaller than device logical block size";
2139 wc->block_size_bits = __ffs(wc->block_size);
2141 wc->max_writeback_jobs = MAX_WRITEBACK_JOBS;
2142 wc->autocommit_blocks = !WC_MODE_PMEM(wc) ? AUTOCOMMIT_BLOCKS_SSD : AUTOCOMMIT_BLOCKS_PMEM;
2143 wc->autocommit_jiffies = msecs_to_jiffies(AUTOCOMMIT_MSEC);
2146 * Parse optional arguments
2148 r = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
2152 while (opt_params) {
2153 string = dm_shift_arg(&as), opt_params--;
2154 if (!strcasecmp(string, "start_sector") && opt_params >= 1) {
2155 unsigned long long start_sector;
2156 string = dm_shift_arg(&as), opt_params--;
2157 if (sscanf(string, "%llu%c", &start_sector, &dummy) != 1)
2158 goto invalid_optional;
2159 wc->start_sector = start_sector;
2160 if (wc->start_sector != start_sector ||
2161 wc->start_sector >= wc->memory_map_size >> SECTOR_SHIFT)
2162 goto invalid_optional;
2163 } else if (!strcasecmp(string, "high_watermark") && opt_params >= 1) {
2164 string = dm_shift_arg(&as), opt_params--;
2165 if (sscanf(string, "%d%c", &high_wm_percent, &dummy) != 1)
2166 goto invalid_optional;
2167 if (high_wm_percent < 0 || high_wm_percent > 100)
2168 goto invalid_optional;
2169 wc->high_wm_percent_set = true;
2170 } else if (!strcasecmp(string, "low_watermark") && opt_params >= 1) {
2171 string = dm_shift_arg(&as), opt_params--;
2172 if (sscanf(string, "%d%c", &low_wm_percent, &dummy) != 1)
2173 goto invalid_optional;
2174 if (low_wm_percent < 0 || low_wm_percent > 100)
2175 goto invalid_optional;
2176 wc->low_wm_percent_set = true;
2177 } else if (!strcasecmp(string, "writeback_jobs") && opt_params >= 1) {
2178 string = dm_shift_arg(&as), opt_params--;
2179 if (sscanf(string, "%u%c", &wc->max_writeback_jobs, &dummy) != 1)
2180 goto invalid_optional;
2181 wc->max_writeback_jobs_set = true;
2182 } else if (!strcasecmp(string, "autocommit_blocks") && opt_params >= 1) {
2183 string = dm_shift_arg(&as), opt_params--;
2184 if (sscanf(string, "%u%c", &wc->autocommit_blocks, &dummy) != 1)
2185 goto invalid_optional;
2186 wc->autocommit_blocks_set = true;
2187 } else if (!strcasecmp(string, "autocommit_time") && opt_params >= 1) {
2188 unsigned autocommit_msecs;
2189 string = dm_shift_arg(&as), opt_params--;
2190 if (sscanf(string, "%u%c", &autocommit_msecs, &dummy) != 1)
2191 goto invalid_optional;
2192 if (autocommit_msecs > 3600000)
2193 goto invalid_optional;
2194 wc->autocommit_jiffies = msecs_to_jiffies(autocommit_msecs);
2195 wc->autocommit_time_set = true;
2196 } else if (!strcasecmp(string, "max_age") && opt_params >= 1) {
2197 unsigned max_age_msecs;
2198 string = dm_shift_arg(&as), opt_params--;
2199 if (sscanf(string, "%u%c", &max_age_msecs, &dummy) != 1)
2200 goto invalid_optional;
2201 if (max_age_msecs > 86400000)
2202 goto invalid_optional;
2203 wc->max_age = msecs_to_jiffies(max_age_msecs);
2204 } else if (!strcasecmp(string, "cleaner")) {
2206 } else if (!strcasecmp(string, "fua")) {
2207 if (WC_MODE_PMEM(wc)) {
2208 wc->writeback_fua = true;
2209 wc->writeback_fua_set = true;
2210 } else goto invalid_optional;
2211 } else if (!strcasecmp(string, "nofua")) {
2212 if (WC_MODE_PMEM(wc)) {
2213 wc->writeback_fua = false;
2214 wc->writeback_fua_set = true;
2215 } else goto invalid_optional;
2219 ti->error = "Invalid optional argument";
2224 if (high_wm_percent < low_wm_percent) {
2226 ti->error = "High watermark must be greater than or equal to low watermark";
2230 if (WC_MODE_PMEM(wc)) {
2231 r = persistent_memory_claim(wc);
2233 ti->error = "Unable to map persistent memory for cache";
2237 size_t n_blocks, n_metadata_blocks;
2238 uint64_t n_bitmap_bits;
2240 wc->memory_map_size -= (uint64_t)wc->start_sector << SECTOR_SHIFT;
2242 bio_list_init(&wc->flush_list);
2243 wc->flush_thread = kthread_create(writecache_flush_thread, wc, "dm_writecache_flush");
2244 if (IS_ERR(wc->flush_thread)) {
2245 r = PTR_ERR(wc->flush_thread);
2246 wc->flush_thread = NULL;
2247 ti->error = "Couldn't spawn flush thread";
2250 wake_up_process(wc->flush_thread);
2252 r = calculate_memory_size(wc->memory_map_size, wc->block_size,
2253 &n_blocks, &n_metadata_blocks);
2255 ti->error = "Invalid device size";
2259 n_bitmap_bits = (((uint64_t)n_metadata_blocks << wc->block_size_bits) +
2260 BITMAP_GRANULARITY - 1) / BITMAP_GRANULARITY;
2261 /* this is limitation of test_bit functions */
2262 if (n_bitmap_bits > 1U << 31) {
2264 ti->error = "Invalid device size";
2268 wc->memory_map = vmalloc(n_metadata_blocks << wc->block_size_bits);
2269 if (!wc->memory_map) {
2271 ti->error = "Unable to allocate memory for metadata";
2275 wc->dm_kcopyd = dm_kcopyd_client_create(&dm_kcopyd_throttle);
2276 if (IS_ERR(wc->dm_kcopyd)) {
2277 r = PTR_ERR(wc->dm_kcopyd);
2278 ti->error = "Unable to allocate dm-kcopyd client";
2279 wc->dm_kcopyd = NULL;
2283 wc->metadata_sectors = n_metadata_blocks << (wc->block_size_bits - SECTOR_SHIFT);
2284 wc->dirty_bitmap_size = (n_bitmap_bits + BITS_PER_LONG - 1) /
2285 BITS_PER_LONG * sizeof(unsigned long);
2286 wc->dirty_bitmap = vzalloc(wc->dirty_bitmap_size);
2287 if (!wc->dirty_bitmap) {
2289 ti->error = "Unable to allocate dirty bitmap";
2293 r = writecache_read_metadata(wc, wc->block_size >> SECTOR_SHIFT);
2295 ti->error = "Unable to read first block of metadata";
2300 r = memcpy_mcsafe(&s, sb(wc), sizeof(struct wc_memory_superblock));
2302 ti->error = "Hardware memory error when reading superblock";
2305 if (!le32_to_cpu(s.magic) && !le32_to_cpu(s.version)) {
2306 r = init_memory(wc);
2308 ti->error = "Unable to initialize device";
2311 r = memcpy_mcsafe(&s, sb(wc), sizeof(struct wc_memory_superblock));
2313 ti->error = "Hardware memory error when reading superblock";
2318 if (le32_to_cpu(s.magic) != MEMORY_SUPERBLOCK_MAGIC) {
2319 ti->error = "Invalid magic in the superblock";
2324 if (le32_to_cpu(s.version) != MEMORY_SUPERBLOCK_VERSION) {
2325 ti->error = "Invalid version in the superblock";
2330 if (le32_to_cpu(s.block_size) != wc->block_size) {
2331 ti->error = "Block size does not match superblock";
2336 wc->n_blocks = le64_to_cpu(s.n_blocks);
2338 offset = wc->n_blocks * sizeof(struct wc_memory_entry);
2339 if (offset / sizeof(struct wc_memory_entry) != le64_to_cpu(sb(wc)->n_blocks)) {
2341 ti->error = "Overflow in size calculation";
2345 offset += sizeof(struct wc_memory_superblock);
2346 if (offset < sizeof(struct wc_memory_superblock))
2348 offset = (offset + wc->block_size - 1) & ~(size_t)(wc->block_size - 1);
2349 data_size = wc->n_blocks * (size_t)wc->block_size;
2350 if (!offset || (data_size / wc->block_size != wc->n_blocks) ||
2351 (offset + data_size < offset))
2353 if (offset + data_size > wc->memory_map_size) {
2354 ti->error = "Memory area is too small";
2359 wc->metadata_sectors = offset >> SECTOR_SHIFT;
2360 wc->block_start = (char *)sb(wc) + offset;
2362 x = (uint64_t)wc->n_blocks * (100 - high_wm_percent);
2365 wc->freelist_high_watermark = x;
2366 x = (uint64_t)wc->n_blocks * (100 - low_wm_percent);
2369 wc->freelist_low_watermark = x;
2372 activate_cleaner(wc);
2374 r = writecache_alloc_entries(wc);
2376 ti->error = "Cannot allocate memory";
2380 ti->num_flush_bios = 1;
2381 ti->flush_supported = true;
2382 ti->num_discard_bios = 1;
2384 if (WC_MODE_PMEM(wc))
2385 persistent_memory_flush_cache(wc->memory_map, wc->memory_map_size);
2391 ti->error = "Bad arguments";
2397 static void writecache_status(struct dm_target *ti, status_type_t type,
2398 unsigned status_flags, char *result, unsigned maxlen)
2400 struct dm_writecache *wc = ti->private;
2401 unsigned extra_args;
2406 case STATUSTYPE_INFO:
2407 DMEMIT("%ld %llu %llu %llu", writecache_has_error(wc),
2408 (unsigned long long)wc->n_blocks, (unsigned long long)wc->freelist_size,
2409 (unsigned long long)wc->writeback_size);
2411 case STATUSTYPE_TABLE:
2412 DMEMIT("%c %s %s %u ", WC_MODE_PMEM(wc) ? 'p' : 's',
2413 wc->dev->name, wc->ssd_dev->name, wc->block_size);
2415 if (wc->start_sector)
2417 if (wc->high_wm_percent_set && !wc->cleaner)
2419 if (wc->low_wm_percent_set && !wc->cleaner)
2421 if (wc->max_writeback_jobs_set)
2423 if (wc->autocommit_blocks_set)
2425 if (wc->autocommit_time_set)
2429 if (wc->writeback_fua_set)
2432 DMEMIT("%u", extra_args);
2433 if (wc->start_sector)
2434 DMEMIT(" start_sector %llu", (unsigned long long)wc->start_sector);
2435 if (wc->high_wm_percent_set && !wc->cleaner) {
2436 x = (uint64_t)wc->freelist_high_watermark * 100;
2437 x += wc->n_blocks / 2;
2438 do_div(x, (size_t)wc->n_blocks);
2439 DMEMIT(" high_watermark %u", 100 - (unsigned)x);
2441 if (wc->low_wm_percent_set && !wc->cleaner) {
2442 x = (uint64_t)wc->freelist_low_watermark * 100;
2443 x += wc->n_blocks / 2;
2444 do_div(x, (size_t)wc->n_blocks);
2445 DMEMIT(" low_watermark %u", 100 - (unsigned)x);
2447 if (wc->max_writeback_jobs_set)
2448 DMEMIT(" writeback_jobs %u", wc->max_writeback_jobs);
2449 if (wc->autocommit_blocks_set)
2450 DMEMIT(" autocommit_blocks %u", wc->autocommit_blocks);
2451 if (wc->autocommit_time_set)
2452 DMEMIT(" autocommit_time %u", jiffies_to_msecs(wc->autocommit_jiffies));
2453 if (wc->max_age != MAX_AGE_UNSPECIFIED)
2454 DMEMIT(" max_age %u", jiffies_to_msecs(wc->max_age));
2457 if (wc->writeback_fua_set)
2458 DMEMIT(" %sfua", wc->writeback_fua ? "" : "no");
2463 static struct target_type writecache_target = {
2464 .name = "writecache",
2465 .version = {1, 3, 0},
2466 .module = THIS_MODULE,
2467 .ctr = writecache_ctr,
2468 .dtr = writecache_dtr,
2469 .status = writecache_status,
2470 .postsuspend = writecache_suspend,
2471 .resume = writecache_resume,
2472 .message = writecache_message,
2473 .map = writecache_map,
2474 .end_io = writecache_end_io,
2475 .iterate_devices = writecache_iterate_devices,
2476 .io_hints = writecache_io_hints,
2479 static int __init dm_writecache_init(void)
2483 r = dm_register_target(&writecache_target);
2485 DMERR("register failed %d", r);
2492 static void __exit dm_writecache_exit(void)
2494 dm_unregister_target(&writecache_target);
2497 module_init(dm_writecache_init);
2498 module_exit(dm_writecache_exit);
2500 MODULE_DESCRIPTION(DM_NAME " writecache target");
2501 MODULE_AUTHOR("Mikulas Patocka <dm-devel@redhat.com>");
2502 MODULE_LICENSE("GPL");