blob: 18320444fb0a9b71a2bba75fec062a54a0c03f68 [file] [log] [blame]
// 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>
#include <linux/delay.h>
#include "dm-io-tracker.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 PAUSE_WRITEBACK (HZ * 3)
#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[];
};
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 long pause;
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;
bool metadata_only:1;
bool pause_set:1;
unsigned high_wm_percent_value;
unsigned low_wm_percent_value;
unsigned autocommit_time_value;
unsigned max_age_value;
unsigned pause_value;
unsigned writeback_all;
struct workqueue_struct *writeback_wq;
struct work_struct writeback_work;
struct work_struct flush_work;
struct dm_io_tracker iot;
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;
struct {
unsigned long long reads;
unsigned long long read_hits;
unsigned long long writes;
unsigned long long write_hits_uncommitted;
unsigned long long write_hits_committed;
unsigned long long writes_around;
unsigned long long writes_allocate;
unsigned long long writes_blocked_on_freelist;
unsigned long long flushes;
unsigned long long discards;
} stats;
};
#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, &region, 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, &region, 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, &region, 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, &region, 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 = bdev_nr_sectors(wc->dev->bdev);
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 process_clear_stats_mesg(unsigned argc, char **argv, struct dm_writecache *wc)
{
if (argc != 1)
return -EINVAL;
wc_lock(wc);
memset(&wc->stats, 0, sizeof wc->stats);
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 if (!strcasecmp(argv[0], "clear_stats"))
r = process_clear_stats_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 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_local(&bv);
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);
}
kunmap_local(buf);
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);
}
enum wc_map_op {
WC_MAP_SUBMIT,
WC_MAP_REMAP,
WC_MAP_REMAP_ORIGIN,
WC_MAP_RETURN,
WC_MAP_ERROR,
};
static enum wc_map_op writecache_map_remap_origin(struct dm_writecache *wc, struct bio *bio,
struct wc_entry *e)
{
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);
}
return WC_MAP_REMAP_ORIGIN;
}
static enum wc_map_op writecache_map_read(struct dm_writecache *wc, struct bio *bio)
{
enum wc_map_op map_op;
struct wc_entry *e;
read_next_block:
wc->stats.reads++;
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) {
wc->stats.read_hits++;
if (WC_MODE_PMEM(wc)) {
bio_copy_block(wc, bio, memory_data(wc, e));
if (bio->bi_iter.bi_size)
goto read_next_block;
map_op = WC_MAP_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);
map_op = WC_MAP_REMAP;
}
} else {
map_op = writecache_map_remap_origin(wc, bio, e);
}
return map_op;
}
static enum wc_map_op writecache_bio_copy_ssd(struct dm_writecache *wc, struct bio *bio,
struct wc_entry *e, bool search_used)
{
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);
}
return WC_MAP_REMAP;
}
static enum wc_map_op writecache_map_write(struct dm_writecache *wc, struct bio *bio)
{
struct wc_entry *e;
do {
bool found_entry = false;
bool search_used = false;
wc->stats.writes++;
if (writecache_has_error(wc))
return WC_MAP_ERROR;
e = writecache_find_entry(wc, bio->bi_iter.bi_sector, 0);
if (e) {
if (!writecache_entry_is_committed(wc, e)) {
wc->stats.write_hits_uncommitted++;
search_used = true;
goto bio_copy;
}
wc->stats.write_hits_committed++;
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) ||
(wc->metadata_only && !(bio->bi_opf & REQ_META)))
goto direct_write;
}
e = writecache_pop_from_freelist(wc, (sector_t)-1);
if (unlikely(!e)) {
if (!WC_MODE_PMEM(wc) && !found_entry) {
direct_write:
wc->stats.writes_around++;
e = writecache_find_entry(wc, bio->bi_iter.bi_sector, WFE_RETURN_FOLLOWING);
return writecache_map_remap_origin(wc, bio, e);
}
wc->stats.writes_blocked_on_freelist++;
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++;
wc->stats.writes_allocate++;
bio_copy:
if (WC_MODE_PMEM(wc))
bio_copy_block(wc, bio, memory_data(wc, e));
else
return writecache_bio_copy_ssd(wc, bio, e, search_used);
} 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);
return WC_MAP_SUBMIT;
}
static enum wc_map_op writecache_map_flush(struct dm_writecache *wc, struct bio *bio)
{
if (writecache_has_error(wc))
return WC_MAP_ERROR;
if (WC_MODE_PMEM(wc)) {
wc->stats.flushes++;
writecache_flush(wc);
if (writecache_has_error(wc))
return WC_MAP_ERROR;
else if (unlikely(wc->cleaner) || unlikely(wc->metadata_only))
return WC_MAP_REMAP_ORIGIN;
return WC_MAP_SUBMIT;
}
/* SSD: */
if (dm_bio_get_target_bio_nr(bio))
return WC_MAP_REMAP_ORIGIN;
wc->stats.flushes++;
writecache_offload_bio(wc, bio);
return WC_MAP_RETURN;
}
static enum wc_map_op writecache_map_discard(struct dm_writecache *wc, struct bio *bio)
{
wc->stats.discards++;
if (writecache_has_error(wc))
return WC_MAP_ERROR;
if (WC_MODE_PMEM(wc)) {
writecache_discard(wc, bio->bi_iter.bi_sector, bio_end_sector(bio));
return WC_MAP_REMAP_ORIGIN;
}
/* SSD: */
writecache_offload_bio(wc, bio);
return WC_MAP_RETURN;
}
static int writecache_map(struct dm_target *ti, struct bio *bio)
{
struct dm_writecache *wc = ti->private;
enum wc_map_op map_op;
bio->bi_private = NULL;
wc_lock(wc);
if (unlikely(bio->bi_opf & REQ_PREFLUSH)) {
map_op = writecache_map_flush(wc, bio);
goto done;
}
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);
map_op = WC_MAP_ERROR;
goto done;
}
if (unlikely(bio_op(bio) == REQ_OP_DISCARD)) {
map_op = writecache_map_discard(wc, bio);
goto done;
}
if (bio_data_dir(bio) == READ)
map_op = writecache_map_read(wc, bio);
else
map_op = writecache_map_write(wc, bio);
done:
switch (map_op) {
case WC_MAP_REMAP_ORIGIN:
if (likely(wc->pause != 0)) {
if (bio_op(bio) == REQ_OP_WRITE) {
dm_iot_io_begin(&wc->iot, 1);
bio->bi_private = (void *)2;
}
}
bio_set_dev(bio, wc->dev->bdev);
wc_unlock(wc);
return DM_MAPIO_REMAPPED;
case WC_MAP_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;
case WC_MAP_SUBMIT:
wc_unlock(wc);
bio_endio(bio);
return DM_MAPIO_SUBMITTED;
case WC_MAP_RETURN:
wc_unlock(wc);
return DM_MAPIO_SUBMITTED;
case WC_MAP_ERROR:
wc_unlock(wc);
bio_io_error(bio);
return DM_MAPIO_SUBMITTED;
default:
BUG();
return -1;
}
}
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 == (void *)1) {
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]);
} else if (bio->bi_private == (void *)2) {
dm_iot_io_end(&wc->iot, 1);
}
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)
{
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));
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))
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;
if (!WC_MODE_PMEM(wc)) {
/* Wait for any active kcopyd work on behalf of ssd writeback */
dm_kcopyd_client_flush(wc->dm_kcopyd);
}
if (likely(wc->pause != 0)) {
while (1) {
unsigned long idle;
if (unlikely(wc->cleaner) || unlikely(wc->writeback_all) ||
unlikely(dm_suspended(wc->ti)))
break;
idle = dm_iot_idle_time(&wc->iot);
if (idle >= wc->pause)
break;
idle = wc->pause - idle;
if (idle > HZ)
idle = HZ;
schedule_timeout_idle(idle);
}
}
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)) {
if (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_move(&e->lru, &skipped);
cond_resched();
continue;
}
}
wc->writeback_size++;
list_move(&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_move(&g->lru, &wbl.list);
wbl.size++;
g->write_in_progress = true;
g->wc_list_contiguous = BIO_MAX_VECS;
f = g;
e->wc_list_contiguous++;
if (unlikely(e->wc_list_contiguous == BIO_MAX_VECS)) {
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);
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);
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, 18, "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);
dm_iot_init(&wc->iot);
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 {
wc->pause = PAUSE_WRITEBACK;
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 if (!strcasecmp(string, "metadata_only")) {
wc->metadata_only = true;
} else if (!strcasecmp(string, "pause_writeback") && opt_params >= 1) {
unsigned pause_msecs;
if (WC_MODE_PMEM(wc))
goto invalid_optional;
string = dm_shift_arg(&as), opt_params--;
if (sscanf(string, "%u%c", &pause_msecs, &dummy) != 1)
goto invalid_optional;
if (pause_msecs > 60000)
goto invalid_optional;
wc->pause = msecs_to_jiffies(pause_msecs);
wc->pause_set = true;
wc->pause_value = pause_msecs;
} 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);