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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Copyright (C) 2018 Red Hat. All rights reserved.
- *
- * This file is released under the GPL.
- */
- #include <linux/device-mapper.h>
- #include <linux/module.h>
- #include <linux/init.h>
- #include <linux/vmalloc.h>
- #include <linux/kthread.h>
- #include <linux/dm-io.h>
- #include <linux/dm-kcopyd.h>
- #include <linux/dax.h>
- #include <linux/pfn_t.h>
- #include <linux/libnvdimm.h>
- #define DM_MSG_PREFIX "writecache"
- #define HIGH_WATERMARK 50
- #define LOW_WATERMARK 45
- #define MAX_WRITEBACK_JOBS 0
- #define ENDIO_LATENCY 16
- #define WRITEBACK_LATENCY 64
- #define AUTOCOMMIT_BLOCKS_SSD 65536
- #define AUTOCOMMIT_BLOCKS_PMEM 64
- #define AUTOCOMMIT_MSEC 1000
- #define MAX_AGE_DIV 16
- #define MAX_AGE_UNSPECIFIED -1UL
- #define BITMAP_GRANULARITY 65536
- #if BITMAP_GRANULARITY < PAGE_SIZE
- #undef BITMAP_GRANULARITY
- #define BITMAP_GRANULARITY PAGE_SIZE
- #endif
- #if IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API) && IS_ENABLED(CONFIG_DAX_DRIVER)
- #define DM_WRITECACHE_HAS_PMEM
- #endif
- #ifdef DM_WRITECACHE_HAS_PMEM
- #define pmem_assign(dest, src) \
- do { \
- typeof(dest) uniq = (src); \
- memcpy_flushcache(&(dest), &uniq, sizeof(dest)); \
- } while (0)
- #else
- #define pmem_assign(dest, src) ((dest) = (src))
- #endif
- #if IS_ENABLED(CONFIG_ARCH_HAS_COPY_MC) && defined(DM_WRITECACHE_HAS_PMEM)
- #define DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
- #endif
- #define MEMORY_SUPERBLOCK_MAGIC 0x23489321
- #define MEMORY_SUPERBLOCK_VERSION 1
- struct wc_memory_entry {
- __le64 original_sector;
- __le64 seq_count;
- };
- struct wc_memory_superblock {
- union {
- struct {
- __le32 magic;
- __le32 version;
- __le32 block_size;
- __le32 pad;
- __le64 n_blocks;
- __le64 seq_count;
- };
- __le64 padding[8];
- };
- struct wc_memory_entry entries[0];
- };
- struct wc_entry {
- struct rb_node rb_node;
- struct list_head lru;
- unsigned short wc_list_contiguous;
- bool write_in_progress
- #if BITS_PER_LONG == 64
- :1
- #endif
- ;
- unsigned long index
- #if BITS_PER_LONG == 64
- :47
- #endif
- ;
- unsigned long age;
- #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
- uint64_t original_sector;
- uint64_t seq_count;
- #endif
- };
- #ifdef DM_WRITECACHE_HAS_PMEM
- #define WC_MODE_PMEM(wc) ((wc)->pmem_mode)
- #define WC_MODE_FUA(wc) ((wc)->writeback_fua)
- #else
- #define WC_MODE_PMEM(wc) false
- #define WC_MODE_FUA(wc) false
- #endif
- #define WC_MODE_SORT_FREELIST(wc) (!WC_MODE_PMEM(wc))
- struct dm_writecache {
- struct mutex lock;
- struct list_head lru;
- union {
- struct list_head freelist;
- struct {
- struct rb_root freetree;
- struct wc_entry *current_free;
- };
- };
- struct rb_root tree;
- size_t freelist_size;
- size_t writeback_size;
- size_t freelist_high_watermark;
- size_t freelist_low_watermark;
- unsigned long max_age;
- unsigned uncommitted_blocks;
- unsigned autocommit_blocks;
- unsigned max_writeback_jobs;
- int error;
- unsigned long autocommit_jiffies;
- struct timer_list autocommit_timer;
- struct wait_queue_head freelist_wait;
- struct timer_list max_age_timer;
- atomic_t bio_in_progress[2];
- struct wait_queue_head bio_in_progress_wait[2];
- struct dm_target *ti;
- struct dm_dev *dev;
- struct dm_dev *ssd_dev;
- sector_t start_sector;
- void *memory_map;
- uint64_t memory_map_size;
- size_t metadata_sectors;
- size_t n_blocks;
- uint64_t seq_count;
- sector_t data_device_sectors;
- void *block_start;
- struct wc_entry *entries;
- unsigned block_size;
- unsigned char block_size_bits;
- bool pmem_mode:1;
- bool writeback_fua:1;
- bool overwrote_committed:1;
- bool memory_vmapped:1;
- bool start_sector_set:1;
- bool high_wm_percent_set:1;
- bool low_wm_percent_set:1;
- bool max_writeback_jobs_set:1;
- bool autocommit_blocks_set:1;
- bool autocommit_time_set:1;
- bool max_age_set:1;
- bool writeback_fua_set:1;
- bool flush_on_suspend:1;
- bool cleaner:1;
- bool cleaner_set:1;
- unsigned high_wm_percent_value;
- unsigned low_wm_percent_value;
- unsigned autocommit_time_value;
- unsigned max_age_value;
- unsigned writeback_all;
- struct workqueue_struct *writeback_wq;
- struct work_struct writeback_work;
- struct work_struct flush_work;
- struct dm_io_client *dm_io;
- raw_spinlock_t endio_list_lock;
- struct list_head endio_list;
- struct task_struct *endio_thread;
- struct task_struct *flush_thread;
- struct bio_list flush_list;
- struct dm_kcopyd_client *dm_kcopyd;
- unsigned long *dirty_bitmap;
- unsigned dirty_bitmap_size;
- struct bio_set bio_set;
- mempool_t copy_pool;
- };
- #define WB_LIST_INLINE 16
- struct writeback_struct {
- struct list_head endio_entry;
- struct dm_writecache *wc;
- struct wc_entry **wc_list;
- unsigned wc_list_n;
- struct wc_entry *wc_list_inline[WB_LIST_INLINE];
- struct bio bio;
- };
- struct copy_struct {
- struct list_head endio_entry;
- struct dm_writecache *wc;
- struct wc_entry *e;
- unsigned n_entries;
- int error;
- };
- DECLARE_DM_KCOPYD_THROTTLE_WITH_MODULE_PARM(dm_writecache_throttle,
- "A percentage of time allocated for data copying");
- static void wc_lock(struct dm_writecache *wc)
- {
- mutex_lock(&wc->lock);
- }
- static void wc_unlock(struct dm_writecache *wc)
- {
- mutex_unlock(&wc->lock);
- }
- #ifdef DM_WRITECACHE_HAS_PMEM
- static int persistent_memory_claim(struct dm_writecache *wc)
- {
- int r;
- loff_t s;
- long p, da;
- pfn_t pfn;
- int id;
- struct page **pages;
- sector_t offset;
- wc->memory_vmapped = false;
- s = wc->memory_map_size;
- p = s >> PAGE_SHIFT;
- if (!p) {
- r = -EINVAL;
- goto err1;
- }
- if (p != s >> PAGE_SHIFT) {
- r = -EOVERFLOW;
- goto err1;
- }
- offset = get_start_sect(wc->ssd_dev->bdev);
- if (offset & (PAGE_SIZE / 512 - 1)) {
- r = -EINVAL;
- goto err1;
- }
- offset >>= PAGE_SHIFT - 9;
- id = dax_read_lock();
- da = dax_direct_access(wc->ssd_dev->dax_dev, offset, p, &wc->memory_map, &pfn);
- if (da < 0) {
- wc->memory_map = NULL;
- r = da;
- goto err2;
- }
- if (!pfn_t_has_page(pfn)) {
- wc->memory_map = NULL;
- r = -EOPNOTSUPP;
- goto err2;
- }
- if (da != p) {
- long i;
- wc->memory_map = NULL;
- pages = kvmalloc_array(p, sizeof(struct page *), GFP_KERNEL);
- if (!pages) {
- r = -ENOMEM;
- goto err2;
- }
- i = 0;
- do {
- long daa;
- daa = dax_direct_access(wc->ssd_dev->dax_dev, offset + i, p - i,
- NULL, &pfn);
- if (daa <= 0) {
- r = daa ? daa : -EINVAL;
- goto err3;
- }
- if (!pfn_t_has_page(pfn)) {
- r = -EOPNOTSUPP;
- goto err3;
- }
- while (daa-- && i < p) {
- pages[i++] = pfn_t_to_page(pfn);
- pfn.val++;
- if (!(i & 15))
- cond_resched();
- }
- } while (i < p);
- wc->memory_map = vmap(pages, p, VM_MAP, PAGE_KERNEL);
- if (!wc->memory_map) {
- r = -ENOMEM;
- goto err3;
- }
- kvfree(pages);
- wc->memory_vmapped = true;
- }
- dax_read_unlock(id);
- wc->memory_map += (size_t)wc->start_sector << SECTOR_SHIFT;
- wc->memory_map_size -= (size_t)wc->start_sector << SECTOR_SHIFT;
- return 0;
- err3:
- kvfree(pages);
- err2:
- dax_read_unlock(id);
- err1:
- return r;
- }
- #else
- static int persistent_memory_claim(struct dm_writecache *wc)
- {
- return -EOPNOTSUPP;
- }
- #endif
- static void persistent_memory_release(struct dm_writecache *wc)
- {
- if (wc->memory_vmapped)
- vunmap(wc->memory_map - ((size_t)wc->start_sector << SECTOR_SHIFT));
- }
- static struct page *persistent_memory_page(void *addr)
- {
- if (is_vmalloc_addr(addr))
- return vmalloc_to_page(addr);
- else
- return virt_to_page(addr);
- }
- static unsigned persistent_memory_page_offset(void *addr)
- {
- return (unsigned long)addr & (PAGE_SIZE - 1);
- }
- static void persistent_memory_flush_cache(void *ptr, size_t size)
- {
- if (is_vmalloc_addr(ptr))
- flush_kernel_vmap_range(ptr, size);
- }
- static void persistent_memory_invalidate_cache(void *ptr, size_t size)
- {
- if (is_vmalloc_addr(ptr))
- invalidate_kernel_vmap_range(ptr, size);
- }
- static struct wc_memory_superblock *sb(struct dm_writecache *wc)
- {
- return wc->memory_map;
- }
- static struct wc_memory_entry *memory_entry(struct dm_writecache *wc, struct wc_entry *e)
- {
- return &sb(wc)->entries[e->index];
- }
- static void *memory_data(struct dm_writecache *wc, struct wc_entry *e)
- {
- return (char *)wc->block_start + (e->index << wc->block_size_bits);
- }
- static sector_t cache_sector(struct dm_writecache *wc, struct wc_entry *e)
- {
- return wc->start_sector + wc->metadata_sectors +
- ((sector_t)e->index << (wc->block_size_bits - SECTOR_SHIFT));
- }
- static uint64_t read_original_sector(struct dm_writecache *wc, struct wc_entry *e)
- {
- #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
- return e->original_sector;
- #else
- return le64_to_cpu(memory_entry(wc, e)->original_sector);
- #endif
- }
- static uint64_t read_seq_count(struct dm_writecache *wc, struct wc_entry *e)
- {
- #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
- return e->seq_count;
- #else
- return le64_to_cpu(memory_entry(wc, e)->seq_count);
- #endif
- }
- static void clear_seq_count(struct dm_writecache *wc, struct wc_entry *e)
- {
- #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
- e->seq_count = -1;
- #endif
- pmem_assign(memory_entry(wc, e)->seq_count, cpu_to_le64(-1));
- }
- static void write_original_sector_seq_count(struct dm_writecache *wc, struct wc_entry *e,
- uint64_t original_sector, uint64_t seq_count)
- {
- struct wc_memory_entry me;
- #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
- e->original_sector = original_sector;
- e->seq_count = seq_count;
- #endif
- me.original_sector = cpu_to_le64(original_sector);
- me.seq_count = cpu_to_le64(seq_count);
- pmem_assign(*memory_entry(wc, e), me);
- }
- #define writecache_error(wc, err, msg, arg...) \
- do { \
- if (!cmpxchg(&(wc)->error, 0, err)) \
- DMERR(msg, ##arg); \
- wake_up(&(wc)->freelist_wait); \
- } while (0)
- #define writecache_has_error(wc) (unlikely(READ_ONCE((wc)->error)))
- static void writecache_flush_all_metadata(struct dm_writecache *wc)
- {
- if (!WC_MODE_PMEM(wc))
- memset(wc->dirty_bitmap, -1, wc->dirty_bitmap_size);
- }
- static void writecache_flush_region(struct dm_writecache *wc, void *ptr, size_t size)
- {
- if (!WC_MODE_PMEM(wc))
- __set_bit(((char *)ptr - (char *)wc->memory_map) / BITMAP_GRANULARITY,
- wc->dirty_bitmap);
- }
- static void writecache_disk_flush(struct dm_writecache *wc, struct dm_dev *dev);
- struct io_notify {
- struct dm_writecache *wc;
- struct completion c;
- atomic_t count;
- };
- static void writecache_notify_io(unsigned long error, void *context)
- {
- struct io_notify *endio = context;
- if (unlikely(error != 0))
- writecache_error(endio->wc, -EIO, "error writing metadata");
- BUG_ON(atomic_read(&endio->count) <= 0);
- if (atomic_dec_and_test(&endio->count))
- complete(&endio->c);
- }
- static void writecache_wait_for_ios(struct dm_writecache *wc, int direction)
- {
- wait_event(wc->bio_in_progress_wait[direction],
- !atomic_read(&wc->bio_in_progress[direction]));
- }
- static void ssd_commit_flushed(struct dm_writecache *wc, bool wait_for_ios)
- {
- struct dm_io_region region;
- struct dm_io_request req;
- struct io_notify endio = {
- wc,
- COMPLETION_INITIALIZER_ONSTACK(endio.c),
- ATOMIC_INIT(1),
- };
- unsigned bitmap_bits = wc->dirty_bitmap_size * 8;
- unsigned i = 0;
- while (1) {
- unsigned j;
- i = find_next_bit(wc->dirty_bitmap, bitmap_bits, i);
- if (unlikely(i == bitmap_bits))
- break;
- j = find_next_zero_bit(wc->dirty_bitmap, bitmap_bits, i);
- region.bdev = wc->ssd_dev->bdev;
- region.sector = (sector_t)i * (BITMAP_GRANULARITY >> SECTOR_SHIFT);
- region.count = (sector_t)(j - i) * (BITMAP_GRANULARITY >> SECTOR_SHIFT);
- if (unlikely(region.sector >= wc->metadata_sectors))
- break;
- if (unlikely(region.sector + region.count > wc->metadata_sectors))
- region.count = wc->metadata_sectors - region.sector;
- region.sector += wc->start_sector;
- atomic_inc(&endio.count);
- req.bi_op = REQ_OP_WRITE;
- req.bi_op_flags = REQ_SYNC;
- req.mem.type = DM_IO_VMA;
- req.mem.ptr.vma = (char *)wc->memory_map + (size_t)i * BITMAP_GRANULARITY;
- req.client = wc->dm_io;
- req.notify.fn = writecache_notify_io;
- req.notify.context = &endio;
- /* writing via async dm-io (implied by notify.fn above) won't return an error */
- (void) dm_io(&req, 1, ®ion, NULL);
- i = j;
- }
- writecache_notify_io(0, &endio);
- wait_for_completion_io(&endio.c);
- if (wait_for_ios)
- writecache_wait_for_ios(wc, WRITE);
- writecache_disk_flush(wc, wc->ssd_dev);
- memset(wc->dirty_bitmap, 0, wc->dirty_bitmap_size);
- }
- static void ssd_commit_superblock(struct dm_writecache *wc)
- {
- int r;
- struct dm_io_region region;
- struct dm_io_request req;
- region.bdev = wc->ssd_dev->bdev;
- region.sector = 0;
- region.count = max(4096U, wc->block_size) >> SECTOR_SHIFT;
- if (unlikely(region.sector + region.count > wc->metadata_sectors))
- region.count = wc->metadata_sectors - region.sector;
- region.sector += wc->start_sector;
- req.bi_op = REQ_OP_WRITE;
- req.bi_op_flags = REQ_SYNC | REQ_FUA;
- req.mem.type = DM_IO_VMA;
- req.mem.ptr.vma = (char *)wc->memory_map;
- req.client = wc->dm_io;
- req.notify.fn = NULL;
- req.notify.context = NULL;
- r = dm_io(&req, 1, ®ion, NULL);
- if (unlikely(r))
- writecache_error(wc, r, "error writing superblock");
- }
- static void writecache_commit_flushed(struct dm_writecache *wc, bool wait_for_ios)
- {
- if (WC_MODE_PMEM(wc))
- pmem_wmb();
- else
- ssd_commit_flushed(wc, wait_for_ios);
- }
- static void writecache_disk_flush(struct dm_writecache *wc, struct dm_dev *dev)
- {
- int r;
- struct dm_io_region region;
- struct dm_io_request req;
- region.bdev = dev->bdev;
- region.sector = 0;
- region.count = 0;
- req.bi_op = REQ_OP_WRITE;
- req.bi_op_flags = REQ_PREFLUSH;
- req.mem.type = DM_IO_KMEM;
- req.mem.ptr.addr = NULL;
- req.client = wc->dm_io;
- req.notify.fn = NULL;
- r = dm_io(&req, 1, ®ion, NULL);
- if (unlikely(r))
- writecache_error(wc, r, "error flushing metadata: %d", r);
- }
- #define WFE_RETURN_FOLLOWING 1
- #define WFE_LOWEST_SEQ 2
- static struct wc_entry *writecache_find_entry(struct dm_writecache *wc,
- uint64_t block, int flags)
- {
- struct wc_entry *e;
- struct rb_node *node = wc->tree.rb_node;
- if (unlikely(!node))
- return NULL;
- while (1) {
- e = container_of(node, struct wc_entry, rb_node);
- if (read_original_sector(wc, e) == block)
- break;
- node = (read_original_sector(wc, e) >= block ?
- e->rb_node.rb_left : e->rb_node.rb_right);
- if (unlikely(!node)) {
- if (!(flags & WFE_RETURN_FOLLOWING))
- return NULL;
- if (read_original_sector(wc, e) >= block) {
- return e;
- } else {
- node = rb_next(&e->rb_node);
- if (unlikely(!node))
- return NULL;
- e = container_of(node, struct wc_entry, rb_node);
- return e;
- }
- }
- }
- while (1) {
- struct wc_entry *e2;
- if (flags & WFE_LOWEST_SEQ)
- node = rb_prev(&e->rb_node);
- else
- node = rb_next(&e->rb_node);
- if (unlikely(!node))
- return e;
- e2 = container_of(node, struct wc_entry, rb_node);
- if (read_original_sector(wc, e2) != block)
- return e;
- e = e2;
- }
- }
- static void writecache_insert_entry(struct dm_writecache *wc, struct wc_entry *ins)
- {
- struct wc_entry *e;
- struct rb_node **node = &wc->tree.rb_node, *parent = NULL;
- while (*node) {
- e = container_of(*node, struct wc_entry, rb_node);
- parent = &e->rb_node;
- if (read_original_sector(wc, e) > read_original_sector(wc, ins))
- node = &parent->rb_left;
- else
- node = &parent->rb_right;
- }
- rb_link_node(&ins->rb_node, parent, node);
- rb_insert_color(&ins->rb_node, &wc->tree);
- list_add(&ins->lru, &wc->lru);
- ins->age = jiffies;
- }
- static void writecache_unlink(struct dm_writecache *wc, struct wc_entry *e)
- {
- list_del(&e->lru);
- rb_erase(&e->rb_node, &wc->tree);
- }
- static void writecache_add_to_freelist(struct dm_writecache *wc, struct wc_entry *e)
- {
- if (WC_MODE_SORT_FREELIST(wc)) {
- struct rb_node **node = &wc->freetree.rb_node, *parent = NULL;
- if (unlikely(!*node))
- wc->current_free = e;
- while (*node) {
- parent = *node;
- if (&e->rb_node < *node)
- node = &parent->rb_left;
- else
- node = &parent->rb_right;
- }
- rb_link_node(&e->rb_node, parent, node);
- rb_insert_color(&e->rb_node, &wc->freetree);
- } else {
- list_add_tail(&e->lru, &wc->freelist);
- }
- wc->freelist_size++;
- }
- static inline void writecache_verify_watermark(struct dm_writecache *wc)
- {
- if (unlikely(wc->freelist_size + wc->writeback_size <= wc->freelist_high_watermark))
- queue_work(wc->writeback_wq, &wc->writeback_work);
- }
- static void writecache_max_age_timer(struct timer_list *t)
- {
- struct dm_writecache *wc = from_timer(wc, t, max_age_timer);
- if (!dm_suspended(wc->ti) && !writecache_has_error(wc)) {
- queue_work(wc->writeback_wq, &wc->writeback_work);
- mod_timer(&wc->max_age_timer, jiffies + wc->max_age / MAX_AGE_DIV);
- }
- }
- static struct wc_entry *writecache_pop_from_freelist(struct dm_writecache *wc, sector_t expected_sector)
- {
- struct wc_entry *e;
- if (WC_MODE_SORT_FREELIST(wc)) {
- struct rb_node *next;
- if (unlikely(!wc->current_free))
- return NULL;
- e = wc->current_free;
- if (expected_sector != (sector_t)-1 && unlikely(cache_sector(wc, e) != expected_sector))
- return NULL;
- next = rb_next(&e->rb_node);
- rb_erase(&e->rb_node, &wc->freetree);
- if (unlikely(!next))
- next = rb_first(&wc->freetree);
- wc->current_free = next ? container_of(next, struct wc_entry, rb_node) : NULL;
- } else {
- if (unlikely(list_empty(&wc->freelist)))
- return NULL;
- e = container_of(wc->freelist.next, struct wc_entry, lru);
- if (expected_sector != (sector_t)-1 && unlikely(cache_sector(wc, e) != expected_sector))
- return NULL;
- list_del(&e->lru);
- }
- wc->freelist_size--;
- writecache_verify_watermark(wc);
- return e;
- }
- static void writecache_free_entry(struct dm_writecache *wc, struct wc_entry *e)
- {
- writecache_unlink(wc, e);
- writecache_add_to_freelist(wc, e);
- clear_seq_count(wc, e);
- writecache_flush_region(wc, memory_entry(wc, e), sizeof(struct wc_memory_entry));
- if (unlikely(waitqueue_active(&wc->freelist_wait)))
- wake_up(&wc->freelist_wait);
- }
- static void writecache_wait_on_freelist(struct dm_writecache *wc)
- {
- DEFINE_WAIT(wait);
- prepare_to_wait(&wc->freelist_wait, &wait, TASK_UNINTERRUPTIBLE);
- wc_unlock(wc);
- io_schedule();
- finish_wait(&wc->freelist_wait, &wait);
- wc_lock(wc);
- }
- static void writecache_poison_lists(struct dm_writecache *wc)
- {
- /*
- * Catch incorrect access to these values while the device is suspended.
- */
- memset(&wc->tree, -1, sizeof wc->tree);
- wc->lru.next = LIST_POISON1;
- wc->lru.prev = LIST_POISON2;
- wc->freelist.next = LIST_POISON1;
- wc->freelist.prev = LIST_POISON2;
- }
- static void writecache_flush_entry(struct dm_writecache *wc, struct wc_entry *e)
- {
- writecache_flush_region(wc, memory_entry(wc, e), sizeof(struct wc_memory_entry));
- if (WC_MODE_PMEM(wc))
- writecache_flush_region(wc, memory_data(wc, e), wc->block_size);
- }
- static bool writecache_entry_is_committed(struct dm_writecache *wc, struct wc_entry *e)
- {
- return read_seq_count(wc, e) < wc->seq_count;
- }
- static void writecache_flush(struct dm_writecache *wc)
- {
- struct wc_entry *e, *e2;
- bool need_flush_after_free;
- wc->uncommitted_blocks = 0;
- del_timer(&wc->autocommit_timer);
- if (list_empty(&wc->lru))
- return;
- e = container_of(wc->lru.next, struct wc_entry, lru);
- if (writecache_entry_is_committed(wc, e)) {
- if (wc->overwrote_committed) {
- writecache_wait_for_ios(wc, WRITE);
- writecache_disk_flush(wc, wc->ssd_dev);
- wc->overwrote_committed = false;
- }
- return;
- }
- while (1) {
- writecache_flush_entry(wc, e);
- if (unlikely(e->lru.next == &wc->lru))
- break;
- e2 = container_of(e->lru.next, struct wc_entry, lru);
- if (writecache_entry_is_committed(wc, e2))
- break;
- e = e2;
- cond_resched();
- }
- writecache_commit_flushed(wc, true);
- wc->seq_count++;
- pmem_assign(sb(wc)->seq_count, cpu_to_le64(wc->seq_count));
- if (WC_MODE_PMEM(wc))
- writecache_commit_flushed(wc, false);
- else
- ssd_commit_superblock(wc);
- wc->overwrote_committed = false;
- need_flush_after_free = false;
- while (1) {
- /* Free another committed entry with lower seq-count */
- struct rb_node *rb_node = rb_prev(&e->rb_node);
- if (rb_node) {
- e2 = container_of(rb_node, struct wc_entry, rb_node);
- if (read_original_sector(wc, e2) == read_original_sector(wc, e) &&
- likely(!e2->write_in_progress)) {
- writecache_free_entry(wc, e2);
- need_flush_after_free = true;
- }
- }
- if (unlikely(e->lru.prev == &wc->lru))
- break;
- e = container_of(e->lru.prev, struct wc_entry, lru);
- cond_resched();
- }
- if (need_flush_after_free)
- writecache_commit_flushed(wc, false);
- }
- static void writecache_flush_work(struct work_struct *work)
- {
- struct dm_writecache *wc = container_of(work, struct dm_writecache, flush_work);
- wc_lock(wc);
- writecache_flush(wc);
- wc_unlock(wc);
- }
- static void writecache_autocommit_timer(struct timer_list *t)
- {
- struct dm_writecache *wc = from_timer(wc, t, autocommit_timer);
- if (!writecache_has_error(wc))
- queue_work(wc->writeback_wq, &wc->flush_work);
- }
- static void writecache_schedule_autocommit(struct dm_writecache *wc)
- {
- if (!timer_pending(&wc->autocommit_timer))
- mod_timer(&wc->autocommit_timer, jiffies + wc->autocommit_jiffies);
- }
- static void writecache_discard(struct dm_writecache *wc, sector_t start, sector_t end)
- {
- struct wc_entry *e;
- bool discarded_something = false;
- e = writecache_find_entry(wc, start, WFE_RETURN_FOLLOWING | WFE_LOWEST_SEQ);
- if (unlikely(!e))
- return;
- while (read_original_sector(wc, e) < end) {
- struct rb_node *node = rb_next(&e->rb_node);
- if (likely(!e->write_in_progress)) {
- if (!discarded_something) {
- if (!WC_MODE_PMEM(wc)) {
- writecache_wait_for_ios(wc, READ);
- writecache_wait_for_ios(wc, WRITE);
- }
- discarded_something = true;
- }
- if (!writecache_entry_is_committed(wc, e))
- wc->uncommitted_blocks--;
- writecache_free_entry(wc, e);
- }
- if (unlikely(!node))
- break;
- e = container_of(node, struct wc_entry, rb_node);
- }
- if (discarded_something)
- writecache_commit_flushed(wc, false);
- }
- static bool writecache_wait_for_writeback(struct dm_writecache *wc)
- {
- if (wc->writeback_size) {
- writecache_wait_on_freelist(wc);
- return true;
- }
- return false;
- }
- static void writecache_suspend(struct dm_target *ti)
- {
- struct dm_writecache *wc = ti->private;
- bool flush_on_suspend;
- del_timer_sync(&wc->autocommit_timer);
- del_timer_sync(&wc->max_age_timer);
- wc_lock(wc);
- writecache_flush(wc);
- flush_on_suspend = wc->flush_on_suspend;
- if (flush_on_suspend) {
- wc->flush_on_suspend = false;
- wc->writeback_all++;
- queue_work(wc->writeback_wq, &wc->writeback_work);
- }
- wc_unlock(wc);
- drain_workqueue(wc->writeback_wq);
- wc_lock(wc);
- if (flush_on_suspend)
- wc->writeback_all--;
- while (writecache_wait_for_writeback(wc));
- if (WC_MODE_PMEM(wc))
- persistent_memory_flush_cache(wc->memory_map, wc->memory_map_size);
- writecache_poison_lists(wc);
- wc_unlock(wc);
- }
- static int writecache_alloc_entries(struct dm_writecache *wc)
- {
- size_t b;
- if (wc->entries)
- return 0;
- wc->entries = vmalloc(array_size(sizeof(struct wc_entry), wc->n_blocks));
- if (!wc->entries)
- return -ENOMEM;
- for (b = 0; b < wc->n_blocks; b++) {
- struct wc_entry *e = &wc->entries[b];
- e->index = b;
- e->write_in_progress = false;
- cond_resched();
- }
- return 0;
- }
- static int writecache_read_metadata(struct dm_writecache *wc, sector_t n_sectors)
- {
- struct dm_io_region region;
- struct dm_io_request req;
- region.bdev = wc->ssd_dev->bdev;
- region.sector = wc->start_sector;
- region.count = n_sectors;
- req.bi_op = REQ_OP_READ;
- req.bi_op_flags = REQ_SYNC;
- req.mem.type = DM_IO_VMA;
- req.mem.ptr.vma = (char *)wc->memory_map;
- req.client = wc->dm_io;
- req.notify.fn = NULL;
- return dm_io(&req, 1, ®ion, NULL);
- }
- static void writecache_resume(struct dm_target *ti)
- {
- struct dm_writecache *wc = ti->private;
- size_t b;
- bool need_flush = false;
- __le64 sb_seq_count;
- int r;
- wc_lock(wc);
- wc->data_device_sectors = i_size_read(wc->dev->bdev->bd_inode) >> SECTOR_SHIFT;
- if (WC_MODE_PMEM(wc)) {
- persistent_memory_invalidate_cache(wc->memory_map, wc->memory_map_size);
- } else {
- r = writecache_read_metadata(wc, wc->metadata_sectors);
- if (r) {
- size_t sb_entries_offset;
- writecache_error(wc, r, "unable to read metadata: %d", r);
- sb_entries_offset = offsetof(struct wc_memory_superblock, entries);
- memset((char *)wc->memory_map + sb_entries_offset, -1,
- (wc->metadata_sectors << SECTOR_SHIFT) - sb_entries_offset);
- }
- }
- wc->tree = RB_ROOT;
- INIT_LIST_HEAD(&wc->lru);
- if (WC_MODE_SORT_FREELIST(wc)) {
- wc->freetree = RB_ROOT;
- wc->current_free = NULL;
- } else {
- INIT_LIST_HEAD(&wc->freelist);
- }
- wc->freelist_size = 0;
- r = copy_mc_to_kernel(&sb_seq_count, &sb(wc)->seq_count,
- sizeof(uint64_t));
- if (r) {
- writecache_error(wc, r, "hardware memory error when reading superblock: %d", r);
- sb_seq_count = cpu_to_le64(0);
- }
- wc->seq_count = le64_to_cpu(sb_seq_count);
- #ifdef DM_WRITECACHE_HANDLE_HARDWARE_ERRORS
- for (b = 0; b < wc->n_blocks; b++) {
- struct wc_entry *e = &wc->entries[b];
- struct wc_memory_entry wme;
- if (writecache_has_error(wc)) {
- e->original_sector = -1;
- e->seq_count = -1;
- continue;
- }
- r = copy_mc_to_kernel(&wme, memory_entry(wc, e),
- sizeof(struct wc_memory_entry));
- if (r) {
- writecache_error(wc, r, "hardware memory error when reading metadata entry %lu: %d",
- (unsigned long)b, r);
- e->original_sector = -1;
- e->seq_count = -1;
- } else {
- e->original_sector = le64_to_cpu(wme.original_sector);
- e->seq_count = le64_to_cpu(wme.seq_count);
- }
- cond_resched();
- }
- #endif
- for (b = 0; b < wc->n_blocks; b++) {
- struct wc_entry *e = &wc->entries[b];
- if (!writecache_entry_is_committed(wc, e)) {
- if (read_seq_count(wc, e) != -1) {
- erase_this:
- clear_seq_count(wc, e);
- need_flush = true;
- }
- writecache_add_to_freelist(wc, e);
- } else {
- struct wc_entry *old;
- old = writecache_find_entry(wc, read_original_sector(wc, e), 0);
- if (!old) {
- writecache_insert_entry(wc, e);
- } else {
- if (read_seq_count(wc, old) == read_seq_count(wc, e)) {
- writecache_error(wc, -EINVAL,
- "two identical entries, position %llu, sector %llu, sequence %llu",
- (unsigned long long)b, (unsigned long long)read_original_sector(wc, e),
- (unsigned long long)read_seq_count(wc, e));
- }
- if (read_seq_count(wc, old) > read_seq_count(wc, e)) {
- goto erase_this;
- } else {
- writecache_free_entry(wc, old);
- writecache_insert_entry(wc, e);
- need_flush = true;
- }
- }
- }
- cond_resched();
- }
- if (need_flush) {
- writecache_flush_all_metadata(wc);
- writecache_commit_flushed(wc, false);
- }
- writecache_verify_watermark(wc);
- if (wc->max_age != MAX_AGE_UNSPECIFIED)
- mod_timer(&wc->max_age_timer, jiffies + wc->max_age / MAX_AGE_DIV);
- wc_unlock(wc);
- }
- static int process_flush_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
- {
- if (argc != 1)
- return -EINVAL;
- wc_lock(wc);
- if (dm_suspended(wc->ti)) {
- wc_unlock(wc);
- return -EBUSY;
- }
- if (writecache_has_error(wc)) {
- wc_unlock(wc);
- return -EIO;
- }
- writecache_flush(wc);
- wc->writeback_all++;
- queue_work(wc->writeback_wq, &wc->writeback_work);
- wc_unlock(wc);
- flush_workqueue(wc->writeback_wq);
- wc_lock(wc);
- wc->writeback_all--;
- if (writecache_has_error(wc)) {
- wc_unlock(wc);
- return -EIO;
- }
- wc_unlock(wc);
- return 0;
- }
- static int process_flush_on_suspend_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
- {
- if (argc != 1)
- return -EINVAL;
- wc_lock(wc);
- wc->flush_on_suspend = true;
- wc_unlock(wc);
- return 0;
- }
- static void activate_cleaner(struct dm_writecache *wc)
- {
- wc->flush_on_suspend = true;
- wc->cleaner = true;
- wc->freelist_high_watermark = wc->n_blocks;
- wc->freelist_low_watermark = wc->n_blocks;
- }
- static int process_cleaner_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
- {
- if (argc != 1)
- return -EINVAL;
- wc_lock(wc);
- activate_cleaner(wc);
- if (!dm_suspended(wc->ti))
- writecache_verify_watermark(wc);
- wc_unlock(wc);
- return 0;
- }
- static int writecache_message(struct dm_target *ti, unsigned argc, char **argv,
- char *result, unsigned maxlen)
- {
- int r = -EINVAL;
- struct dm_writecache *wc = ti->private;
- if (!strcasecmp(argv[0], "flush"))
- r = process_flush_mesg(argc, argv, wc);
- else if (!strcasecmp(argv[0], "flush_on_suspend"))
- r = process_flush_on_suspend_mesg(argc, argv, wc);
- else if (!strcasecmp(argv[0], "cleaner"))
- r = process_cleaner_mesg(argc, argv, wc);
- else
- DMERR("unrecognised message received: %s", argv[0]);
- return r;
- }
- static void memcpy_flushcache_optimized(void *dest, void *source, size_t size)
- {
- /*
- * clflushopt performs better with block size 1024, 2048, 4096
- * non-temporal stores perform better with block size 512
- *
- * block size 512 1024 2048 4096
- * movnti 496 MB/s 642 MB/s 725 MB/s 744 MB/s
- * clflushopt 373 MB/s 688 MB/s 1.1 GB/s 1.2 GB/s
- *
- * We see that movnti performs better for 512-byte blocks, and
- * clflushopt performs better for 1024-byte and larger blocks. So, we
- * prefer clflushopt for sizes >= 768.
- *
- * NOTE: this happens to be the case now (with dm-writecache's single
- * threaded model) but re-evaluate this once memcpy_flushcache() is
- * enabled to use movdir64b which might invalidate this performance
- * advantage seen with cache-allocating-writes plus flushing.
- */
- #ifdef CONFIG_X86
- if (static_cpu_has(X86_FEATURE_CLFLUSHOPT) &&
- likely(boot_cpu_data.x86_clflush_size == 64) &&
- likely(size >= 768)) {
- do {
- memcpy((void *)dest, (void *)source, 64);
- clflushopt((void *)dest);
- dest += 64;
- source += 64;
- size -= 64;
- } while (size >= 64);
- return;
- }
- #endif
- memcpy_flushcache(dest, source, size);
- }
- static void bio_copy_block(struct dm_writecache *wc, struct bio *bio, void *data)
- {
- void *buf;
- unsigned long flags;
- unsigned size;
- int rw = bio_data_dir(bio);
- unsigned remaining_size = wc->block_size;
- do {
- struct bio_vec bv = bio_iter_iovec(bio, bio->bi_iter);
- buf = bvec_kmap_irq(&bv, &flags);
- size = bv.bv_len;
- if (unlikely(size > remaining_size))
- size = remaining_size;
- if (rw == READ) {
- int r;
- r = copy_mc_to_kernel(buf, data, size);
- flush_dcache_page(bio_page(bio));
- if (unlikely(r)) {
- writecache_error(wc, r, "hardware memory error when reading data: %d", r);
- bio->bi_status = BLK_STS_IOERR;
- }
- } else {
- flush_dcache_page(bio_page(bio));
- memcpy_flushcache_optimized(data, buf, size);
- }
- bvec_kunmap_irq(buf, &flags);
- data = (char *)data + size;
- remaining_size -= size;
- bio_advance(bio, size);
- } while (unlikely(remaining_size));
- }
- static int writecache_flush_thread(void *data)
- {
- struct dm_writecache *wc = data;
- while (1) {
- struct bio *bio;
- wc_lock(wc);
- bio = bio_list_pop(&wc->flush_list);
- if (!bio) {
- set_current_state(TASK_INTERRUPTIBLE);
- wc_unlock(wc);
- if (unlikely(kthread_should_stop())) {
- set_current_state(TASK_RUNNING);
- break;
- }
- schedule();
- continue;
- }
- if (bio_op(bio) == REQ_OP_DISCARD) {
- writecache_discard(wc, bio->bi_iter.bi_sector,
- bio_end_sector(bio));
- wc_unlock(wc);
- bio_set_dev(bio, wc->dev->bdev);
- submit_bio_noacct(bio);
- } else {
- writecache_flush(wc);
- wc_unlock(wc);
- if (writecache_has_error(wc))
- bio->bi_status = BLK_STS_IOERR;
- bio_endio(bio);
- }
- }
- return 0;
- }
- static void writecache_offload_bio(struct dm_writecache *wc, struct bio *bio)
- {
- if (bio_list_empty(&wc->flush_list))
- wake_up_process(wc->flush_thread);
- bio_list_add(&wc->flush_list, bio);
- }
- static int writecache_map(struct dm_target *ti, struct bio *bio)
- {
- struct wc_entry *e;
- struct dm_writecache *wc = ti->private;
- bio->bi_private = NULL;
- wc_lock(wc);
- if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
- if (writecache_has_error(wc))
- goto unlock_error;
- if (WC_MODE_PMEM(wc)) {
- writecache_flush(wc);
- if (writecache_has_error(wc))
- goto unlock_error;
- if (unlikely(wc->cleaner))
- goto unlock_remap_origin;
- goto unlock_submit;
- } else {
- if (dm_bio_get_target_bio_nr(bio))
- goto unlock_remap_origin;
- writecache_offload_bio(wc, bio);
- goto unlock_return;
- }
- }
- bio->bi_iter.bi_sector = dm_target_offset(ti, bio->bi_iter.bi_sector);
- if (unlikely((((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) &
- (wc->block_size / 512 - 1)) != 0)) {
- DMERR("I/O is not aligned, sector %llu, size %u, block size %u",
- (unsigned long long)bio->bi_iter.bi_sector,
- bio->bi_iter.bi_size, wc->block_size);
- goto unlock_error;
- }
- if (unlikely(bio_op(bio) == REQ_OP_DISCARD)) {
- if (writecache_has_error(wc))
- goto unlock_error;
- if (WC_MODE_PMEM(wc)) {
- writecache_discard(wc, bio->bi_iter.bi_sector, bio_end_sector(bio));
- goto unlock_remap_origin;
- } else {
- writecache_offload_bio(wc, bio);
- goto unlock_return;
- }
- }
- if (bio_data_dir(bio) == READ) {
- read_next_block:
- e = writecache_find_entry(wc, bio->bi_iter.bi_sector, WFE_RETURN_FOLLOWING);
- if (e && read_original_sector(wc, e) == bio->bi_iter.bi_sector) {
- if (WC_MODE_PMEM(wc)) {
- bio_copy_block(wc, bio, memory_data(wc, e));
- if (bio->bi_iter.bi_size)
- goto read_next_block;
- goto unlock_submit;
- } else {
- dm_accept_partial_bio(bio, wc->block_size >> SECTOR_SHIFT);
- bio_set_dev(bio, wc->ssd_dev->bdev);
- bio->bi_iter.bi_sector = cache_sector(wc, e);
- if (!writecache_entry_is_committed(wc, e))
- writecache_wait_for_ios(wc, WRITE);
- goto unlock_remap;
- }
- } else {
- if (e) {
- sector_t next_boundary =
- read_original_sector(wc, e) - bio->bi_iter.bi_sector;
- if (next_boundary < bio->bi_iter.bi_size >> SECTOR_SHIFT) {
- dm_accept_partial_bio(bio, next_boundary);
- }
- }
- goto unlock_remap_origin;
- }
- } else {
- do {
- bool found_entry = false;
- bool search_used = false;
- if (writecache_has_error(wc))
- goto unlock_error;
- e = writecache_find_entry(wc, bio->bi_iter.bi_sector, 0);
- if (e) {
- if (!writecache_entry_is_committed(wc, e)) {
- search_used = true;
- goto bio_copy;
- }
- if (!WC_MODE_PMEM(wc) && !e->write_in_progress) {
- wc->overwrote_committed = true;
- search_used = true;
- goto bio_copy;
- }
- found_entry = true;
- } else {
- if (unlikely(wc->cleaner))
- goto direct_write;
- }
- e = writecache_pop_from_freelist(wc, (sector_t)-1);
- if (unlikely(!e)) {
- if (!WC_MODE_PMEM(wc) && !found_entry) {
- direct_write:
- e = writecache_find_entry(wc, bio->bi_iter.bi_sector, WFE_RETURN_FOLLOWING);
- if (e) {
- sector_t next_boundary = read_original_sector(wc, e) - bio->bi_iter.bi_sector;
- BUG_ON(!next_boundary);
- if (next_boundary < bio->bi_iter.bi_size >> SECTOR_SHIFT) {
- dm_accept_partial_bio(bio, next_boundary);
- }
- }
- goto unlock_remap_origin;
- }
- writecache_wait_on_freelist(wc);
- continue;
- }
- write_original_sector_seq_count(wc, e, bio->bi_iter.bi_sector, wc->seq_count);
- writecache_insert_entry(wc, e);
- wc->uncommitted_blocks++;
- bio_copy:
- if (WC_MODE_PMEM(wc)) {
- bio_copy_block(wc, bio, memory_data(wc, e));
- } else {
- unsigned bio_size = wc->block_size;
- sector_t start_cache_sec = cache_sector(wc, e);
- sector_t current_cache_sec = start_cache_sec + (bio_size >> SECTOR_SHIFT);
- while (bio_size < bio->bi_iter.bi_size) {
- if (!search_used) {
- struct wc_entry *f = writecache_pop_from_freelist(wc, current_cache_sec);
- if (!f)
- break;
- write_original_sector_seq_count(wc, f, bio->bi_iter.bi_sector +
- (bio_size >> SECTOR_SHIFT), wc->seq_count);
- writecache_insert_entry(wc, f);
- wc->uncommitted_blocks++;
- } else {
- struct wc_entry *f;
- struct rb_node *next = rb_next(&e->rb_node);
- if (!next)
- break;
- f = container_of(next, struct wc_entry, rb_node);
- if (f != e + 1)
- break;
- if (read_original_sector(wc, f) !=
- read_original_sector(wc, e) + (wc->block_size >> SECTOR_SHIFT))
- break;
- if (unlikely(f->write_in_progress))
- break;
- if (writecache_entry_is_committed(wc, f))
- wc->overwrote_committed = true;
- e = f;
- }
- bio_size += wc->block_size;
- current_cache_sec += wc->block_size >> SECTOR_SHIFT;
- }
- bio_set_dev(bio, wc->ssd_dev->bdev);
- bio->bi_iter.bi_sector = start_cache_sec;
- dm_accept_partial_bio(bio, bio_size >> SECTOR_SHIFT);
- if (unlikely(wc->uncommitted_blocks >= wc->autocommit_blocks)) {
- wc->uncommitted_blocks = 0;
- queue_work(wc->writeback_wq, &wc->flush_work);
- } else {
- writecache_schedule_autocommit(wc);
- }
- goto unlock_remap;
- }
- } while (bio->bi_iter.bi_size);
- if (unlikely(bio->bi_opf & REQ_FUA ||
- wc->uncommitted_blocks >= wc->autocommit_blocks))
- writecache_flush(wc);
- else
- writecache_schedule_autocommit(wc);
- goto unlock_submit;
- }
- unlock_remap_origin:
- bio_set_dev(bio, wc->dev->bdev);
- wc_unlock(wc);
- return DM_MAPIO_REMAPPED;
- unlock_remap:
- /* make sure that writecache_end_io decrements bio_in_progress: */
- bio->bi_private = (void *)1;
- atomic_inc(&wc->bio_in_progress[bio_data_dir(bio)]);
- wc_unlock(wc);
- return DM_MAPIO_REMAPPED;
- unlock_submit:
- wc_unlock(wc);
- bio_endio(bio);
- return DM_MAPIO_SUBMITTED;
- unlock_return:
- wc_unlock(wc);
- return DM_MAPIO_SUBMITTED;
- unlock_error:
- wc_unlock(wc);
- bio_io_error(bio);
- return DM_MAPIO_SUBMITTED;
- }
- static int writecache_end_io(struct dm_target *ti, struct bio *bio, blk_status_t *status)
- {
- struct dm_writecache *wc = ti->private;
- if (bio->bi_private != NULL) {
- int dir = bio_data_dir(bio);
- if (atomic_dec_and_test(&wc->bio_in_progress[dir]))
- if (unlikely(waitqueue_active(&wc->bio_in_progress_wait[dir])))
- wake_up(&wc->bio_in_progress_wait[dir]);
- }
- return 0;
- }
- static int writecache_iterate_devices(struct dm_target *ti,
- iterate_devices_callout_fn fn, void *data)
- {
- struct dm_writecache *wc = ti->private;
- return fn(ti, wc->dev, 0, ti->len, data);
- }
- static void writecache_io_hints(struct dm_target *ti, struct queue_limits *limits)
- {
- struct dm_writecache *wc = ti->private;
- if (limits->logical_block_size < wc->block_size)
- limits->logical_block_size = wc->block_size;
- if (limits->physical_block_size < wc->block_size)
- limits->physical_block_size = wc->block_size;
- if (limits->io_min < wc->block_size)
- limits->io_min = wc->block_size;
- }
- static void writecache_writeback_endio(struct bio *bio)
- {
- struct writeback_struct *wb = container_of(bio, struct writeback_struct, bio);
- struct dm_writecache *wc = wb->wc;
- unsigned long flags;
- raw_spin_lock_irqsave(&wc->endio_list_lock, flags);
- if (unlikely(list_empty(&wc->endio_list)))
- wake_up_process(wc->endio_thread);
- list_add_tail(&wb->endio_entry, &wc->endio_list);
- raw_spin_unlock_irqrestore(&wc->endio_list_lock, flags);
- }
- static void writecache_copy_endio(int read_err, unsigned long write_err, void *ptr)
- {
- struct copy_struct *c = ptr;
- struct dm_writecache *wc = c->wc;
- c->error = likely(!(read_err | write_err)) ? 0 : -EIO;
- raw_spin_lock_irq(&wc->endio_list_lock);
- if (unlikely(list_empty(&wc->endio_list)))
- wake_up_process(wc->endio_thread);
- list_add_tail(&c->endio_entry, &wc->endio_list);
- raw_spin_unlock_irq(&wc->endio_list_lock);
- }
- static void __writecache_endio_pmem(struct dm_writecache *wc, struct list_head *list)
- {
- unsigned i;
- struct writeback_struct *wb;
- struct wc_entry *e;
- unsigned long n_walked = 0;
- do {
- wb = list_entry(list->next, struct writeback_struct, endio_entry);
- list_del(&wb->endio_entry);
- if (unlikely(wb->bio.bi_status != BLK_STS_OK))
- writecache_error(wc, blk_status_to_errno(wb->bio.bi_status),
- "write error %d", wb->bio.bi_status);
- i = 0;
- do {
- e = wb->wc_list[i];
- BUG_ON(!e->write_in_progress);
- e->write_in_progress = false;
- INIT_LIST_HEAD(&e->lru);
- if (!writecache_has_error(wc))
- writecache_free_entry(wc, e);
- BUG_ON(!wc->writeback_size);
- wc->writeback_size--;
- n_walked++;
- if (unlikely(n_walked >= ENDIO_LATENCY)) {
- writecache_commit_flushed(wc, false);
- wc_unlock(wc);
- wc_lock(wc);
- n_walked = 0;
- }
- } while (++i < wb->wc_list_n);
- if (wb->wc_list != wb->wc_list_inline)
- kfree(wb->wc_list);
- bio_put(&wb->bio);
- } while (!list_empty(list));
- }
- static void __writecache_endio_ssd(struct dm_writecache *wc, struct list_head *list)
- {
- struct copy_struct *c;
- struct wc_entry *e;
- do {
- c = list_entry(list->next, struct copy_struct, endio_entry);
- list_del(&c->endio_entry);
- if (unlikely(c->error))
- writecache_error(wc, c->error, "copy error");
- e = c->e;
- do {
- BUG_ON(!e->write_in_progress);
- e->write_in_progress = false;
- INIT_LIST_HEAD(&e->lru);
- if (!writecache_has_error(wc))
- writecache_free_entry(wc, e);
- BUG_ON(!wc->writeback_size);
- wc->writeback_size--;
- e++;
- } while (--c->n_entries);
- mempool_free(c, &wc->copy_pool);
- } while (!list_empty(list));
- }
- static int writecache_endio_thread(void *data)
- {
- struct dm_writecache *wc = data;
- while (1) {
- struct list_head list;
- raw_spin_lock_irq(&wc->endio_list_lock);
- if (!list_empty(&wc->endio_list))
- goto pop_from_list;
- set_current_state(TASK_INTERRUPTIBLE);
- raw_spin_unlock_irq(&wc->endio_list_lock);
- if (unlikely(kthread_should_stop())) {
- set_current_state(TASK_RUNNING);
- break;
- }
- schedule();
- continue;
- pop_from_list:
- list = wc->endio_list;
- list.next->prev = list.prev->next = &list;
- INIT_LIST_HEAD(&wc->endio_list);
- raw_spin_unlock_irq(&wc->endio_list_lock);
- if (!WC_MODE_FUA(wc))
- writecache_disk_flush(wc, wc->dev);
- wc_lock(wc);
- if (WC_MODE_PMEM(wc)) {
- __writecache_endio_pmem(wc, &list);
- } else {
- __writecache_endio_ssd(wc, &list);
- writecache_wait_for_ios(wc, READ);
- }
- writecache_commit_flushed(wc, false);
- wc_unlock(wc);
- }
- return 0;
- }
- static bool wc_add_block(struct writeback_struct *wb, struct wc_entry *e, gfp_t gfp)
- {
- struct dm_writecache *wc = wb->wc;
- unsigned block_size = wc->block_size;
- void *address = memory_data(wc, e);
- persistent_memory_flush_cache(address, block_size);
- if (unlikely(bio_end_sector(&wb->bio) >= wc->data_device_sectors))
- return true;
- return bio_add_page(&wb->bio, persistent_memory_page(address),
- block_size, persistent_memory_page_offset(address)) != 0;
- }
- struct writeback_list {
- struct list_head list;
- size_t size;
- };
- static void __writeback_throttle(struct dm_writecache *wc, struct writeback_list *wbl)
- {
- if (unlikely(wc->max_writeback_jobs)) {
- if (READ_ONCE(wc->writeback_size) - wbl->size >= wc->max_writeback_jobs) {
- wc_lock(wc);
- while (wc->writeback_size - wbl->size >= wc->max_writeback_jobs)
- writecache_wait_on_freelist(wc);
- wc_unlock(wc);
- }
- }
- cond_resched();
- }
- static void __writecache_writeback_pmem(struct dm_writecache *wc, struct writeback_list *wbl)
- {
- struct wc_entry *e, *f;
- struct bio *bio;
- struct writeback_struct *wb;
- unsigned max_pages;
- while (wbl->size) {
- wbl->size--;
- e = container_of(wbl->list.prev, struct wc_entry, lru);
- list_del(&e->lru);
- max_pages = e->wc_list_contiguous;
- bio = bio_alloc_bioset(GFP_NOIO, max_pages, &wc->bio_set);
- wb = container_of(bio, struct writeback_struct, bio);
- wb->wc = wc;
- bio->bi_end_io = writecache_writeback_endio;
- bio_set_dev(bio, wc->dev->bdev);
- bio->bi_iter.bi_sector = read_original_sector(wc, e);
- if (max_pages <= WB_LIST_INLINE ||
- unlikely(!(wb->wc_list = kmalloc_array(max_pages, sizeof(struct wc_entry *),
- GFP_NOIO | __GFP_NORETRY |
- __GFP_NOMEMALLOC | __GFP_NOWARN)))) {
- wb->wc_list = wb->wc_list_inline;
- max_pages = WB_LIST_INLINE;
- }
- BUG_ON(!wc_add_block(wb, e, GFP_NOIO));
- wb->wc_list[0] = e;
- wb->wc_list_n = 1;
- while (wbl->size && wb->wc_list_n < max_pages) {
- f = container_of(wbl->list.prev, struct wc_entry, lru);
- if (read_original_sector(wc, f) !=
- read_original_sector(wc, e) + (wc->block_size >> SECTOR_SHIFT))
- break;
- if (!wc_add_block(wb, f, GFP_NOWAIT | __GFP_NOWARN))
- break;
- wbl->size--;
- list_del(&f->lru);
- wb->wc_list[wb->wc_list_n++] = f;
- e = f;
- }
- bio_set_op_attrs(bio, REQ_OP_WRITE, WC_MODE_FUA(wc) * REQ_FUA);
- if (writecache_has_error(wc)) {
- bio->bi_status = BLK_STS_IOERR;
- bio_endio(bio);
- } else if (unlikely(!bio_sectors(bio))) {
- bio->bi_status = BLK_STS_OK;
- bio_endio(bio);
- } else {
- submit_bio(bio);
- }
- __writeback_throttle(wc, wbl);
- }
- }
- static void __writecache_writeback_ssd(struct dm_writecache *wc, struct writeback_list *wbl)
- {
- struct wc_entry *e, *f;
- struct dm_io_region from, to;
- struct copy_struct *c;
- while (wbl->size) {
- unsigned n_sectors;
- wbl->size--;
- e = container_of(wbl->list.prev, struct wc_entry, lru);
- list_del(&e->lru);
- n_sectors = e->wc_list_contiguous << (wc->block_size_bits - SECTOR_SHIFT);
- from.bdev = wc->ssd_dev->bdev;
- from.sector = cache_sector(wc, e);
- from.count = n_sectors;
- to.bdev = wc->dev->bdev;
- to.sector = read_original_sector(wc, e);
- to.count = n_sectors;
- c = mempool_alloc(&wc->copy_pool, GFP_NOIO);
- c->wc = wc;
- c->e = e;
- c->n_entries = e->wc_list_contiguous;
- while ((n_sectors -= wc->block_size >> SECTOR_SHIFT)) {
- wbl->size--;
- f = container_of(wbl->list.prev, struct wc_entry, lru);
- BUG_ON(f != e + 1);
- list_del(&f->lru);
- e = f;
- }
- if (unlikely(to.sector + to.count > wc->data_device_sectors)) {
- if (to.sector >= wc->data_device_sectors) {
- writecache_copy_endio(0, 0, c);
- continue;
- }
- from.count = to.count = wc->data_device_sectors - to.sector;
- }
- dm_kcopyd_copy(wc->dm_kcopyd, &from, 1, &to, 0, writecache_copy_endio, c);
- __writeback_throttle(wc, wbl);
- }
- }
- static void writecache_writeback(struct work_struct *work)
- {
- struct dm_writecache *wc = container_of(work, struct dm_writecache, writeback_work);
- struct blk_plug plug;
- struct wc_entry *f, *g, *e = NULL;
- struct rb_node *node, *next_node;
- struct list_head skipped;
- struct writeback_list wbl;
- unsigned long n_walked;
- wc_lock(wc);
- restart:
- if (writecache_has_error(wc)) {
- wc_unlock(wc);
- return;
- }
- if (unlikely(wc->writeback_all)) {
- if (writecache_wait_for_writeback(wc))
- goto restart;
- }
- if (wc->overwrote_committed) {
- writecache_wait_for_ios(wc, WRITE);
- }
- n_walked = 0;
- INIT_LIST_HEAD(&skipped);
- INIT_LIST_HEAD(&wbl.list);
- wbl.size = 0;
- while (!list_empty(&wc->lru) &&
- (wc->writeback_all ||
- wc->freelist_size + wc->writeback_size <= wc->freelist_low_watermark ||
- (jiffies - container_of(wc->lru.prev, struct wc_entry, lru)->age >=
- wc->max_age - wc->max_age / MAX_AGE_DIV))) {
- n_walked++;
- if (unlikely(n_walked > WRITEBACK_LATENCY) &&
- likely(!wc->writeback_all) && likely(!dm_suspended(wc->ti))) {
- queue_work(wc->writeback_wq, &wc->writeback_work);
- break;
- }
- if (unlikely(wc->writeback_all)) {
- if (unlikely(!e)) {
- writecache_flush(wc);
- e = container_of(rb_first(&wc->tree), struct wc_entry, rb_node);
- } else
- e = g;
- } else
- e = container_of(wc->lru.prev, struct wc_entry, lru);
- BUG_ON(e->write_in_progress);
- if (unlikely(!writecache_entry_is_committed(wc, e))) {
- writecache_flush(wc);
- }
- node = rb_prev(&e->rb_node);
- if (node) {
- f = container_of(node, struct wc_entry, rb_node);
- if (unlikely(read_original_sector(wc, f) ==
- read_original_sector(wc, e))) {
- BUG_ON(!f->write_in_progress);
- list_del(&e->lru);
- list_add(&e->lru, &skipped);
- cond_resched();
- continue;
- }
- }
- wc->writeback_size++;
- list_del(&e->lru);
- list_add(&e->lru, &wbl.list);
- wbl.size++;
- e->write_in_progress = true;
- e->wc_list_contiguous = 1;
- f = e;
- while (1) {
- next_node = rb_next(&f->rb_node);
- if (unlikely(!next_node))
- break;
- g = container_of(next_node, struct wc_entry, rb_node);
- if (unlikely(read_original_sector(wc, g) ==
- read_original_sector(wc, f))) {
- f = g;
- continue;
- }
- if (read_original_sector(wc, g) !=
- read_original_sector(wc, f) + (wc->block_size >> SECTOR_SHIFT))
- break;
- if (unlikely(g->write_in_progress))
- break;
- if (unlikely(!writecache_entry_is_committed(wc, g)))
- break;
- if (!WC_MODE_PMEM(wc)) {
- if (g != f + 1)
- break;
- }
- n_walked++;
- //if (unlikely(n_walked > WRITEBACK_LATENCY) && likely(!wc->writeback_all))
- // break;
- wc->writeback_size++;
- list_del(&g->lru);
- list_add(&g->lru, &wbl.list);
- wbl.size++;
- g->write_in_progress = true;
- g->wc_list_contiguous = BIO_MAX_PAGES;
- f = g;
- e->wc_list_contiguous++;
- if (unlikely(e->wc_list_contiguous == BIO_MAX_PAGES)) {
- if (unlikely(wc->writeback_all)) {
- next_node = rb_next(&f->rb_node);
- if (likely(next_node))
- g = container_of(next_node, struct wc_entry, rb_node);
- }
- break;
- }
- }
- cond_resched();
- }
- if (!list_empty(&skipped)) {
- list_splice_tail(&skipped, &wc->lru);
- /*
- * If we didn't do any progress, we must wait until some
- * writeback finishes to avoid burning CPU in a loop
- */
- if (unlikely(!wbl.size))
- writecache_wait_for_writeback(wc);
- }
- wc_unlock(wc);
- blk_start_plug(&plug);
- if (WC_MODE_PMEM(wc))
- __writecache_writeback_pmem(wc, &wbl);
- else
- __writecache_writeback_ssd(wc, &wbl);
- blk_finish_plug(&plug);
- if (unlikely(wc->writeback_all)) {
- wc_lock(wc);
- while (writecache_wait_for_writeback(wc));
- wc_unlock(wc);
- }
- }
- static int calculate_memory_size(uint64_t device_size, unsigned block_size,
- size_t *n_blocks_p, size_t *n_metadata_blocks_p)
- {
- uint64_t n_blocks, offset;
- struct wc_entry e;
- n_blocks = device_size;
- do_div(n_blocks, block_size + sizeof(struct wc_memory_entry));
- while (1) {
- if (!n_blocks)
- return -ENOSPC;
- /* Verify the following entries[n_blocks] won't overflow */
- if (n_blocks >= ((size_t)-sizeof(struct wc_memory_superblock) /
- sizeof(struct wc_memory_entry)))
- return -EFBIG;
- offset = offsetof(struct wc_memory_superblock, entries[n_blocks]);
- offset = (offset + block_size - 1) & ~(uint64_t)(block_size - 1);
- if (offset + n_blocks * block_size <= device_size)
- break;
- n_blocks--;
- }
- /* check if the bit field overflows */
- e.index = n_blocks;
- if (e.index != n_blocks)
- return -EFBIG;
- if (n_blocks_p)
- *n_blocks_p = n_blocks;
- if (n_metadata_blocks_p)
- *n_metadata_blocks_p = offset >> __ffs(block_size);
- return 0;
- }
- static int init_memory(struct dm_writecache *wc)
- {
- size_t b;
- int r;
- r = calculate_memory_size(wc->memory_map_size, wc->block_size, &wc->n_blocks, NULL);
- if (r)
- return r;
- r = writecache_alloc_entries(wc);
- if (r)
- return r;
- for (b = 0; b < ARRAY_SIZE(sb(wc)->padding); b++)
- pmem_assign(sb(wc)->padding[b], cpu_to_le64(0));
- pmem_assign(sb(wc)->version, cpu_to_le32(MEMORY_SUPERBLOCK_VERSION));
- pmem_assign(sb(wc)->block_size, cpu_to_le32(wc->block_size));
- pmem_assign(sb(wc)->n_blocks, cpu_to_le64(wc->n_blocks));
- pmem_assign(sb(wc)->seq_count, cpu_to_le64(0));
- for (b = 0; b < wc->n_blocks; b++) {
- write_original_sector_seq_count(wc, &wc->entries[b], -1, -1);
- cond_resched();
- }
- writecache_flush_all_metadata(wc);
- writecache_commit_flushed(wc, false);
- pmem_assign(sb(wc)->magic, cpu_to_le32(MEMORY_SUPERBLOCK_MAGIC));
- writecache_flush_region(wc, &sb(wc)->magic, sizeof sb(wc)->magic);
- writecache_commit_flushed(wc, false);
- return 0;
- }
- static void writecache_dtr(struct dm_target *ti)
- {
- struct dm_writecache *wc = ti->private;
- if (!wc)
- return;
- if (wc->endio_thread)
- kthread_stop(wc->endio_thread);
- if (wc->flush_thread)
- kthread_stop(wc->flush_thread);
- bioset_exit(&wc->bio_set);
- mempool_exit(&wc->copy_pool);
- if (wc->writeback_wq)
- destroy_workqueue(wc->writeback_wq);
- if (wc->dev)
- dm_put_device(ti, wc->dev);
- if (wc->ssd_dev)
- dm_put_device(ti, wc->ssd_dev);
- if (wc->entries)
- vfree(wc->entries);
- if (wc->memory_map) {
- if (WC_MODE_PMEM(wc))
- persistent_memory_release(wc);
- else
- vfree(wc->memory_map);
- }
- if (wc->dm_kcopyd)
- dm_kcopyd_client_destroy(wc->dm_kcopyd);
- if (wc->dm_io)
- dm_io_client_destroy(wc->dm_io);
- if (wc->dirty_bitmap)
- vfree(wc->dirty_bitmap);
- kfree(wc);
- }
- static int writecache_ctr(struct dm_target *ti, unsigned argc, char **argv)
- {
- struct dm_writecache *wc;
- struct dm_arg_set as;
- const char *string;
- unsigned opt_params;
- size_t offset, data_size;
- int i, r;
- char dummy;
- int high_wm_percent = HIGH_WATERMARK;
- int low_wm_percent = LOW_WATERMARK;
- uint64_t x;
- struct wc_memory_superblock s;
- static struct dm_arg _args[] = {
- {0, 16, "Invalid number of feature args"},
- };
- as.argc = argc;
- as.argv = argv;
- wc = kzalloc(sizeof(struct dm_writecache), GFP_KERNEL);
- if (!wc) {
- ti->error = "Cannot allocate writecache structure";
- r = -ENOMEM;
- goto bad;
- }
- ti->private = wc;
- wc->ti = ti;
- mutex_init(&wc->lock);
- wc->max_age = MAX_AGE_UNSPECIFIED;
- writecache_poison_lists(wc);
- init_waitqueue_head(&wc->freelist_wait);
- timer_setup(&wc->autocommit_timer, writecache_autocommit_timer, 0);
- timer_setup(&wc->max_age_timer, writecache_max_age_timer, 0);
- for (i = 0; i < 2; i++) {
- atomic_set(&wc->bio_in_progress[i], 0);
- init_waitqueue_head(&wc->bio_in_progress_wait[i]);
- }
- wc->dm_io = dm_io_client_create();
- if (IS_ERR(wc->dm_io)) {
- r = PTR_ERR(wc->dm_io);
- ti->error = "Unable to allocate dm-io client";
- wc->dm_io = NULL;
- goto bad;
- }
- wc->writeback_wq = alloc_workqueue("writecache-writeback", WQ_MEM_RECLAIM, 1);
- if (!wc->writeback_wq) {
- r = -ENOMEM;
- ti->error = "Could not allocate writeback workqueue";
- goto bad;
- }
- INIT_WORK(&wc->writeback_work, writecache_writeback);
- INIT_WORK(&wc->flush_work, writecache_flush_work);
- raw_spin_lock_init(&wc->endio_list_lock);
- INIT_LIST_HEAD(&wc->endio_list);
- wc->endio_thread = kthread_create(writecache_endio_thread, wc, "writecache_endio");
- if (IS_ERR(wc->endio_thread)) {
- r = PTR_ERR(wc->endio_thread);
- wc->endio_thread = NULL;
- ti->error = "Couldn't spawn endio thread";
- goto bad;
- }
- wake_up_process(wc->endio_thread);
- /*
- * Parse the mode (pmem or ssd)
- */
- string = dm_shift_arg(&as);
- if (!string)
- goto bad_arguments;
- if (!strcasecmp(string, "s")) {
- wc->pmem_mode = false;
- } else if (!strcasecmp(string, "p")) {
- #ifdef DM_WRITECACHE_HAS_PMEM
- wc->pmem_mode = true;
- wc->writeback_fua = true;
- #else
- /*
- * If the architecture doesn't support persistent memory or
- * the kernel doesn't support any DAX drivers, this driver can
- * only be used in SSD-only mode.
- */
- r = -EOPNOTSUPP;
- ti->error = "Persistent memory or DAX not supported on this system";
- goto bad;
- #endif
- } else {
- goto bad_arguments;
- }
- if (WC_MODE_PMEM(wc)) {
- r = bioset_init(&wc->bio_set, BIO_POOL_SIZE,
- offsetof(struct writeback_struct, bio),
- BIOSET_NEED_BVECS);
- if (r) {
- ti->error = "Could not allocate bio set";
- goto bad;
- }
- } else {
- r = mempool_init_kmalloc_pool(&wc->copy_pool, 1, sizeof(struct copy_struct));
- if (r) {
- ti->error = "Could not allocate mempool";
- goto bad;
- }
- }
- /*
- * Parse the origin data device
- */
- string = dm_shift_arg(&as);
- if (!string)
- goto bad_arguments;
- r = dm_get_device(ti, string, dm_table_get_mode(ti->table), &wc->dev);
- if (r) {
- ti->error = "Origin data device lookup failed";
- goto bad;
- }
- /*
- * Parse cache data device (be it pmem or ssd)
- */
- string = dm_shift_arg(&as);
- if (!string)
- goto bad_arguments;
- r = dm_get_device(ti, string, dm_table_get_mode(ti->table), &wc->ssd_dev);
- if (r) {
- ti->error = "Cache data device lookup failed";
- goto bad;
- }
- wc->memory_map_size = i_size_read(wc->ssd_dev->bdev->bd_inode);
- /*
- * Parse the cache block size
- */
- string = dm_shift_arg(&as);
- if (!string)
- goto bad_arguments;
- if (sscanf(string, "%u%c", &wc->block_size, &dummy) != 1 ||
- wc->block_size < 512 || wc->block_size > PAGE_SIZE ||
- (wc->block_size & (wc->block_size - 1))) {
- r = -EINVAL;
- ti->error = "Invalid block size";
- goto bad;
- }
- if (wc->block_size < bdev_logical_block_size(wc->dev->bdev) ||
- wc->block_size < bdev_logical_block_size(wc->ssd_dev->bdev)) {
- r = -EINVAL;
- ti->error = "Block size is smaller than device logical block size";
- goto bad;
- }
- wc->block_size_bits = __ffs(wc->block_size);
- wc->max_writeback_jobs = MAX_WRITEBACK_JOBS;
- wc->autocommit_blocks = !WC_MODE_PMEM(wc) ? AUTOCOMMIT_BLOCKS_SSD : AUTOCOMMIT_BLOCKS_PMEM;
- wc->autocommit_jiffies = msecs_to_jiffies(AUTOCOMMIT_MSEC);
- /*
- * Parse optional arguments
- */
- r = dm_read_arg_group(_args, &as, &opt_params, &ti->error);
- if (r)
- goto bad;
- while (opt_params) {
- string = dm_shift_arg(&as), opt_params--;
- if (!strcasecmp(string, "start_sector") && opt_params >= 1) {
- unsigned long long start_sector;
- string = dm_shift_arg(&as), opt_params--;
- if (sscanf(string, "%llu%c", &start_sector, &dummy) != 1)
- goto invalid_optional;
- wc->start_sector = start_sector;
- wc->start_sector_set = true;
- if (wc->start_sector != start_sector ||
- wc->start_sector >= wc->memory_map_size >> SECTOR_SHIFT)
- goto invalid_optional;
- } else if (!strcasecmp(string, "high_watermark") && opt_params >= 1) {
- string = dm_shift_arg(&as), opt_params--;
- if (sscanf(string, "%d%c", &high_wm_percent, &dummy) != 1)
- goto invalid_optional;
- if (high_wm_percent < 0 || high_wm_percent > 100)
- goto invalid_optional;
- wc->high_wm_percent_value = high_wm_percent;
- wc->high_wm_percent_set = true;
- } else if (!strcasecmp(string, "low_watermark") && opt_params >= 1) {
- string = dm_shift_arg(&as), opt_params--;
- if (sscanf(string, "%d%c", &low_wm_percent, &dummy) != 1)
- goto invalid_optional;
- if (low_wm_percent < 0 || low_wm_percent > 100)
- goto invalid_optional;
- wc->low_wm_percent_value = low_wm_percent;
- wc->low_wm_percent_set = true;
- } else if (!strcasecmp(string, "writeback_jobs") && opt_params >= 1) {
- string = dm_shift_arg(&as), opt_params--;
- if (sscanf(string, "%u%c", &wc->max_writeback_jobs, &dummy) != 1)
- goto invalid_optional;
- wc->max_writeback_jobs_set = true;
- } else if (!strcasecmp(string, "autocommit_blocks") && opt_params >= 1) {
- string = dm_shift_arg(&as), opt_params--;
- if (sscanf(string, "%u%c", &wc->autocommit_blocks, &dummy) != 1)
- goto invalid_optional;
- wc->autocommit_blocks_set = true;
- } else if (!strcasecmp(string, "autocommit_time") && opt_params >= 1) {
- unsigned autocommit_msecs;
- string = dm_shift_arg(&as), opt_params--;
- if (sscanf(string, "%u%c", &autocommit_msecs, &dummy) != 1)
- goto invalid_optional;
- if (autocommit_msecs > 3600000)
- goto invalid_optional;
- wc->autocommit_jiffies = msecs_to_jiffies(autocommit_msecs);
- wc->autocommit_time_value = autocommit_msecs;
- wc->autocommit_time_set = true;
- } else if (!strcasecmp(string, "max_age") && opt_params >= 1) {
- unsigned max_age_msecs;
- string = dm_shift_arg(&as), opt_params--;
- if (sscanf(string, "%u%c", &max_age_msecs, &dummy) != 1)
- goto invalid_optional;
- if (max_age_msecs > 86400000)
- goto invalid_optional;
- wc->max_age = msecs_to_jiffies(max_age_msecs);
- wc->max_age_set = true;
- wc->max_age_value = max_age_msecs;
- } else if (!strcasecmp(string, "cleaner")) {
- wc->cleaner_set = true;
- wc->cleaner = true;
- } else if (!strcasecmp(string, "fua")) {
- if (WC_MODE_PMEM(wc)) {
- wc->writeback_fua = true;
- wc->writeback_fua_set = true;
- } else goto invalid_optional;
- } else if (!strcasecmp(string, "nofua")) {
- if (WC_MODE_PMEM(wc)) {
- wc->writeback_fua = false;
- wc->writeback_fua_set = true;
- } else goto invalid_optional;
- } else {
- invalid_optional:
- r = -EINVAL;
- ti->error = "Invalid optional argument";
- goto bad;
- }
- }
- if (high_wm_percent < low_wm_percent) {
- r = -EINVAL;
- ti->error = "High watermark must be greater than or equal to low watermark";
- goto bad;
- }
- if (WC_MODE_PMEM(wc)) {
- if (!dax_synchronous(wc->ssd_dev->dax_dev)) {
- r = -EOPNOTSUPP;
- ti->error = "Asynchronous persistent memory not supported as pmem cache";
- goto bad;
- }
- r = persistent_memory_claim(wc);
- if (r) {
- ti->error = "Unable to map persistent memory for cache";
- goto bad;
- }
- } else {
- size_t n_blocks, n_metadata_blocks;
- uint64_t n_bitmap_bits;
- wc->memory_map_size -= (uint64_t)wc->start_sector << SECTOR_SHIFT;
- bio_list_init(&wc->flush_list);
- wc->flush_thread = kthread_create(writecache_flush_thread, wc, "dm_writecache_flush");
- if (IS_ERR(wc->flush_thread)) {
- r = PTR_ERR(wc->flush_thread);
- wc->flush_thread = NULL;
- ti->error = "Couldn't spawn flush thread";
- goto bad;
- }
- wake_up_process(wc->flush_thread);
- r = calculate_memory_size(wc->memory_map_size, wc->block_size,
- &n_blocks, &n_metadata_blocks);
- if (r) {
- ti->error = "Invalid device size";
- goto bad;
- }
- n_bitmap_bits = (((uint64_t)n_metadata_blocks << wc->block_size_bits) +
- BITMAP_GRANULARITY - 1) / BITMAP_GRANULARITY;
- /* this is limitation of test_bit functions */
- if (n_bitmap_bits > 1U << 31) {
- r = -EFBIG;
- ti->error = "Invalid device size";
- goto bad;
- }
- wc->memory_map = vmalloc(n_metadata_blocks << wc->block_size_bits);
- if (!wc->memory_map) {
- r = -ENOMEM;
- ti->error = "Unable to allocate memory for metadata";
- goto bad;
- }
- wc->dm_kcopyd = dm_kcopyd_client_create(&dm_kcopyd_throttle);
- if (IS_ERR(wc->dm_kcopyd)) {
- r = PTR_ERR(wc->dm_kcopyd);
- ti->error = "Unable to allocate dm-kcopyd client";
- wc->dm_kcopyd = NULL;
- goto bad;
- }
- wc->metadata_sectors = n_metadata_blocks << (wc->block_size_bits - SECTOR_SHIFT);
- wc->dirty_bitmap_size = (n_bitmap_bits + BITS_PER_LONG - 1) /
- BITS_PER_LONG * sizeof(unsigned long);
- wc->dirty_bitmap = vzalloc(wc->dirty_bitmap_size);
- if (!wc->dirty_bitmap) {
- r = -ENOMEM;
- ti->error = "Unable to allocate dirty bitmap";
- goto bad;
- }
- r = writecache_read_metadata(wc, wc->block_size >> SECTOR_SHIFT);
- if (r) {
- ti->error = "Unable to read first block of metadata";
- goto bad;
- }
- }
- r = copy_mc_to_kernel(&s, sb(wc), sizeof(struct wc_memory_superblock));
- if (r) {
- ti->error = "Hardware memory error when reading superblock";
- goto bad;
- }
- if (!le32_to_cpu(s.magic) && !le32_to_cpu(s.version)) {
- r = init_memory(wc);
- if (r) {
- ti->error = "Unable to initialize device";
- goto bad;
- }
- r = copy_mc_to_kernel(&s, sb(wc),
- sizeof(struct wc_memory_superblock));
- if (r) {
- ti->error = "Hardware memory error when reading superblock";
- goto bad;
- }
- }
- if (le32_to_cpu(s.magic) != MEMORY_SUPERBLOCK_MAGIC) {
- ti->error = "Invalid magic in the superblock";
- r = -EINVAL;
- goto bad;
- }
- if (le32_to_cpu(s.version) != MEMORY_SUPERBLOCK_VERSION) {
- ti->error = "Invalid version in the superblock";
- r = -EINVAL;
- goto bad;
- }
- if (le32_to_cpu(s.block_size) != wc->block_size) {
- ti->error = "Block size does not match superblock";
- r = -EINVAL;
- goto bad;
- }
- wc->n_blocks = le64_to_cpu(s.n_blocks);
- offset = wc->n_blocks * sizeof(struct wc_memory_entry);
- if (offset / sizeof(struct wc_memory_entry) != le64_to_cpu(sb(wc)->n_blocks)) {
- overflow:
- ti->error = "Overflow in size calculation";
- r = -EINVAL;
- goto bad;
- }
- offset += sizeof(struct wc_memory_superblock);
- if (offset < sizeof(struct wc_memory_superblock))
- goto overflow;
- offset = (offset + wc->block_size - 1) & ~(size_t)(wc->block_size - 1);
- data_size = wc->n_blocks * (size_t)wc->block_size;
- if (!offset || (data_size / wc->block_size != wc->n_blocks) ||
- (offset + data_size < offset))
- goto overflow;
- if (offset + data_size > wc->memory_map_size) {
- ti->error = "Memory area is too small";
- r = -EINVAL;
- goto bad;
- }
- wc->metadata_sectors = offset >> SECTOR_SHIFT;
- wc->block_start = (char *)sb(wc) + offset;
- x = (uint64_t)wc->n_blocks * (100 - high_wm_percent);
- x += 50;
- do_div(x, 100);
- wc->freelist_high_watermark = x;
- x = (uint64_t)wc->n_blocks * (100 - low_wm_percent);
- x += 50;
- do_div(x, 100);
- wc->freelist_low_watermark = x;
- if (wc->cleaner)
- activate_cleaner(wc);
- r = writecache_alloc_entries(wc);
- if (r) {
- ti->error = "Cannot allocate memory";
- goto bad;
- }
- ti->num_flush_bios = WC_MODE_PMEM(wc) ? 1 : 2;
- ti->flush_supported = true;
- ti->num_discard_bios = 1;
- if (WC_MODE_PMEM(wc))
- persistent_memory_flush_cache(wc->memory_map, wc->memory_map_size);
- return 0;
- bad_arguments:
- r = -EINVAL;
- ti->error = "Bad arguments";
- bad:
- writecache_dtr(ti);
- return r;
- }
- static void writecache_status(struct dm_target *ti, status_type_t type,
- unsigned status_flags, char *result, unsigned maxlen)
- {
- struct dm_writecache *wc = ti->private;
- unsigned extra_args;
- unsigned sz = 0;
- switch (type) {
- case STATUSTYPE_INFO:
- DMEMIT("%ld %llu %llu %llu", writecache_has_error(wc),
- (unsigned long long)wc->n_blocks, (unsigned long long)wc->freelist_size,
- (unsigned long long)wc->writeback_size);
- break;
- case STATUSTYPE_TABLE:
- DMEMIT("%c %s %s %u ", WC_MODE_PMEM(wc) ? 'p' : 's',
- wc->dev->name, wc->ssd_dev->name, wc->block_size);
- extra_args = 0;
- if (wc->start_sector_set)
- extra_args += 2;
- if (wc->high_wm_percent_set)
- extra_args += 2;
- if (wc->low_wm_percent_set)
- extra_args += 2;
- if (wc->max_writeback_jobs_set)
- extra_args += 2;
- if (wc->autocommit_blocks_set)
- extra_args += 2;
- if (wc->autocommit_time_set)
- extra_args += 2;
- if (wc->max_age_set)
- extra_args += 2;
- if (wc->cleaner_set)
- extra_args++;
- if (wc->writeback_fua_set)
- extra_args++;
- DMEMIT("%u", extra_args);
- if (wc->start_sector_set)
- DMEMIT(" start_sector %llu", (unsigned long long)wc->start_sector);
- if (wc->high_wm_percent_set)
- DMEMIT(" high_watermark %u", wc->high_wm_percent_value);
- if (wc->low_wm_percent_set)
- DMEMIT(" low_watermark %u", wc->low_wm_percent_value);
- if (wc->max_writeback_jobs_set)
- DMEMIT(" writeback_jobs %u", wc->max_writeback_jobs);
- if (wc->autocommit_blocks_set)
- DMEMIT(" autocommit_blocks %u", wc->autocommit_blocks);
- if (wc->autocommit_time_set)
- DMEMIT(" autocommit_time %u", wc->autocommit_time_value);
- if (wc->max_age_set)
- DMEMIT(" max_age %u", wc->max_age_value);
- if (wc->cleaner_set)
- DMEMIT(" cleaner");
- if (wc->writeback_fua_set)
- DMEMIT(" %sfua", wc->writeback_fua ? "" : "no");
- break;
- }
- }
- static struct target_type writecache_target = {
- .name = "writecache",
- .version = {1, 4, 0},
- .module = THIS_MODULE,
- .ctr = writecache_ctr,
- .dtr = writecache_dtr,
- .status = writecache_status,
- .postsuspend = writecache_suspend,
- .resume = writecache_resume,
- .message = writecache_message,
- .map = writecache_map,
- .end_io = writecache_end_io,
- .iterate_devices = writecache_iterate_devices,
- .io_hints = writecache_io_hints,
- };
- static int __init dm_writecache_init(void)
- {
- int r;
- r = dm_register_target(&writecache_target);
- if (r < 0) {
- DMERR("register failed %d", r);
- return r;
- }
- return 0;
- }
- static void __exit dm_writecache_exit(void)
- {
- dm_unregister_target(&writecache_target);
- }
- module_init(dm_writecache_init);
- module_exit(dm_writecache_exit);
- MODULE_DESCRIPTION(DM_NAME " writecache target");
- MODULE_AUTHOR("Mikulas Patocka <dm-devel@redhat.com>");
- MODULE_LICENSE("GPL");
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