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flashcache_conf.c
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flashcache_conf.c
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/****************************************************************************
* flashcache_conf.c
* FlashCache: Device mapper target for block-level disk caching
*
* Copyright 2010 Facebook, Inc.
* Author: Mohan Srinivasan (mohan@fb.com)
*
* Based on DM-Cache:
* Copyright (C) International Business Machines Corp., 2006
* Author: Ming Zhao (mingzhao@ufl.edu)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; under version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
****************************************************************************/
#include <asm/atomic.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/blkdev.h>
#include <linux/bio.h>
#include <linux/slab.h>
#include <linux/hash.h>
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/pagemap.h>
#include <linux/random.h>
#include <linux/hardirq.h>
#include <linux/sysctl.h>
#include <linux/version.h>
#include <linux/reboot.h>
#include <linux/delay.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,26)
#include "dm.h"
#include "dm-io.h"
#include "dm-bio-list.h"
#include "kcopyd.h"
#else
#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,27)
#include "dm.h"
#endif
#include <linux/device-mapper.h>
#include <linux/bio.h>
#include <linux/dm-kcopyd.h>
#endif
#include "flashcache.h"
#include "flashcache_ioctl.h"
struct cache_c *cache_list_head = NULL;
struct work_struct _kcached_wq;
u_int64_t size_hist[33];
struct kmem_cache *_job_cache;
mempool_t *_job_pool;
struct kmem_cache *_pending_job_cache;
mempool_t *_pending_job_pool;
atomic_t nr_cache_jobs;
atomic_t nr_pending_jobs;
extern struct list_head *_pending_jobs;
extern struct list_head *_io_jobs;
extern struct list_head *_md_io_jobs;
extern struct list_head *_md_complete_jobs;
struct flashcache_control_s {
unsigned long synch_flags;
};
struct flashcache_control_s *flashcache_control;
/* Bit offsets for wait_on_bit_lock() */
#define FLASHCACHE_UPDATE_LIST 0
static int flashcache_notify_reboot(struct notifier_block *this,
unsigned long code, void *x);
static void flashcache_sync_for_remove(struct cache_c *dmc);
extern char *flashcache_sw_version;
static int
flashcache_wait_schedule(void *unused)
{
schedule();
return 0;
}
static int
flashcache_jobs_init(void)
{
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
_job_cache = kmem_cache_create("kcached-jobs",
sizeof(struct kcached_job),
__alignof__(struct kcached_job),
0, NULL, NULL);
#else
_job_cache = kmem_cache_create("kcached-jobs",
sizeof(struct kcached_job),
__alignof__(struct kcached_job),
0, NULL);
#endif
if (!_job_cache)
return -ENOMEM;
_job_pool = mempool_create(MIN_JOBS, mempool_alloc_slab,
mempool_free_slab, _job_cache);
if (!_job_pool) {
kmem_cache_destroy(_job_cache);
return -ENOMEM;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
_pending_job_cache = kmem_cache_create("pending-jobs",
sizeof(struct pending_job),
__alignof__(struct pending_job),
0, NULL, NULL);
#else
_pending_job_cache = kmem_cache_create("pending-jobs",
sizeof(struct pending_job),
__alignof__(struct pending_job),
0, NULL);
#endif
if (!_pending_job_cache) {
mempool_destroy(_job_pool);
kmem_cache_destroy(_job_cache);
return -ENOMEM;
}
_pending_job_pool = mempool_create(MIN_JOBS, mempool_alloc_slab,
mempool_free_slab, _pending_job_cache);
if (!_pending_job_pool) {
kmem_cache_destroy(_pending_job_cache);
mempool_destroy(_job_pool);
kmem_cache_destroy(_job_cache);
return -ENOMEM;
}
return 0;
}
static void
flashcache_jobs_exit(void)
{
VERIFY(flashcache_pending_empty());
VERIFY(flashcache_io_empty());
VERIFY(flashcache_md_io_empty());
VERIFY(flashcache_md_complete_empty());
mempool_destroy(_job_pool);
kmem_cache_destroy(_job_cache);
_job_pool = NULL;
_job_cache = NULL;
mempool_destroy(_pending_job_pool);
kmem_cache_destroy(_pending_job_cache);
_pending_job_pool = NULL;
_pending_job_cache = NULL;
}
static int
flashcache_kcached_init(struct cache_c *dmc)
{
init_waitqueue_head(&dmc->destroyq);
atomic_set(&dmc->nr_jobs, 0);
atomic_set(&dmc->remove_in_prog, 0);
return 0;
}
/*
* Write out the metadata one sector at a time.
* Then dump out the superblock.
*/
static int
flashcache_writeback_md_store(struct cache_c *dmc)
{
struct flash_cacheblock *meta_data_cacheblock, *next_ptr;
struct flash_superblock *header;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,26)
struct io_region where;
#else
struct dm_io_region where;
#endif
int i, j;
int num_valid = 0, num_dirty = 0;
int error;
int write_errors = 0;
int sectors_written = 0, sectors_expected = 0; /* debug */
int slots_written = 0; /* How many cache slots did we fill in this MD io block ? */
meta_data_cacheblock = (struct flash_cacheblock *)vmalloc(METADATA_IO_BLOCKSIZE);
if (!meta_data_cacheblock) {
DMERR("flashcache_writeback_md_store: Unable to allocate memory");
DMERR("flashcache_writeback_md_store: Could not write out cache metadata !");
return 1;
}
where.bdev = dmc->cache_dev->bdev;
where.sector = MD_SECTORS_PER_BLOCK(dmc);
slots_written = 0;
next_ptr = meta_data_cacheblock;
j = MD_SLOTS_PER_BLOCK(dmc);
for (i = 0 ; i < dmc->size ; i++) {
if (dmc->cache[i].cache_state & VALID)
num_valid++;
if (dmc->cache[i].cache_state & DIRTY)
num_dirty++;
next_ptr->dbn = dmc->cache[i].dbn;
#ifdef FLASHCACHE_DO_CHECKSUMS
next_ptr->checksum = dmc->cache[i].checksum;
#endif
next_ptr->cache_state = dmc->cache[i].cache_state &
(INVALID | VALID | DIRTY);
next_ptr++;
slots_written++;
j--;
if (j == 0) {
/*
* Filled the block, write and goto the next metadata block.
*/
if (slots_written == MD_SLOTS_PER_BLOCK(dmc) * METADATA_IO_NUM_BLOCKS(dmc)) {
/*
* Wrote out an entire metadata IO block, write the block to the ssd.
*/
where.count = (slots_written / MD_SLOTS_PER_BLOCK(dmc)) *
MD_SECTORS_PER_BLOCK(dmc);
slots_written = 0;
sectors_written += where.count; /* debug */
error = flashcache_dm_io_sync_vm(dmc, &where, WRITE, meta_data_cacheblock);
if (error) {
write_errors++;
DMERR("flashcache_writeback_md_store: Could not write out cache metadata block %lu error %d !",
where.sector, error);
}
where.sector += where.count; /* Advance offset */
}
/* Move next slot pointer into next block */
next_ptr = (struct flash_cacheblock *)
((caddr_t)meta_data_cacheblock + ((slots_written / MD_SLOTS_PER_BLOCK(dmc)) * MD_BLOCK_BYTES(dmc)));
j = MD_SLOTS_PER_BLOCK(dmc);
}
}
if (next_ptr != meta_data_cacheblock) {
/* Write the remaining last blocks out */
VERIFY(slots_written > 0);
where.count = (slots_written / MD_SLOTS_PER_BLOCK(dmc)) * MD_SECTORS_PER_BLOCK(dmc);
if (slots_written % MD_SLOTS_PER_BLOCK(dmc))
where.count += MD_SECTORS_PER_BLOCK(dmc);
sectors_written += where.count;
error = flashcache_dm_io_sync_vm(dmc, &where, WRITE, meta_data_cacheblock);
if (error) {
write_errors++;
DMERR("flashcache_writeback_md_store: Could not write out cache metadata block %lu error %d !",
where.sector, error);
}
}
/* Debug Tests */
sectors_expected = (dmc->size / MD_SLOTS_PER_BLOCK(dmc)) * MD_SECTORS_PER_BLOCK(dmc);
if (dmc->size % MD_SLOTS_PER_BLOCK(dmc))
sectors_expected += MD_SECTORS_PER_BLOCK(dmc);
if (sectors_expected != sectors_written) {
printk("flashcache_writeback_md_store" "Sector Mismatch ! sectors_expected=%d, sectors_written=%d\n",
sectors_expected, sectors_written);
panic("flashcache_writeback_md_store: sector mismatch\n");
}
vfree((void *)meta_data_cacheblock);
header = (struct flash_superblock *)vmalloc(MD_BLOCK_BYTES(dmc));
if (!header) {
DMERR("flashcache_writeback_md_store: Unable to allocate memory");
DMERR("flashcache_writeback_md_store: Could not write out cache metadata !");
return 1;
}
memset(header, 0, MD_BLOCK_BYTES(dmc));
/* Write the header out last */
if (write_errors == 0) {
if (num_dirty == 0)
header->cache_sb_state = CACHE_MD_STATE_CLEAN;
else
header->cache_sb_state = CACHE_MD_STATE_FASTCLEAN;
} else
header->cache_sb_state = CACHE_MD_STATE_UNSTABLE;
header->block_size = dmc->block_size;
header->md_block_size = dmc->md_block_size;
header->size = dmc->size;
header->assoc = dmc->assoc;
strncpy(header->disk_devname, dmc->disk_devname, DEV_PATHLEN);
strncpy(header->cache_devname, dmc->dm_vdevname, DEV_PATHLEN);
header->cache_devsize = to_sector(dmc->cache_dev->bdev->bd_inode->i_size);
header->disk_devsize = to_sector(dmc->disk_dev->bdev->bd_inode->i_size);
header->cache_version = dmc->on_ssd_version;
DPRINTK("Store metadata to disk: block size(%u), md block size(%u), cache size(%llu)" \
"associativity(%u)",
header->block_size, header->md_block_size, header->size,
header->assoc);
where.sector = 0;
where.count = dmc->md_block_size;
error = flashcache_dm_io_sync_vm(dmc, &where, WRITE, header);
if (error) {
write_errors++;
DMERR("flashcache_writeback_md_store: Could not write out cache metadata superblock %lu error %d !",
where.sector, error);
}
vfree((void *)header);
if (write_errors == 0)
DMINFO("Cache metadata saved to disk");
else {
DMINFO("CRITICAL : There were %d errors in saving cache metadata saved to disk",
write_errors);
if (num_dirty)
DMINFO("CRITICAL : You have likely lost %d dirty blocks", num_dirty);
}
DMINFO("flashcache_writeback_md_store: valid blocks = %d dirty blocks = %d md_sectors = %d\n",
num_valid, num_dirty, dmc->md_blocks * MD_SECTORS_PER_BLOCK(dmc));
return 0;
}
static int
flashcache_writethrough_create(struct cache_c *dmc)
{
sector_t cache_size, dev_size;
sector_t order;
int i;
/*
* Convert size (in sectors) to blocks.
* Then round size (in blocks now) down to a multiple of associativity
*/
dmc->size /= dmc->block_size;
dmc->size = (dmc->size / dmc->assoc) * dmc->assoc;
/* Check cache size against device size */
dev_size = to_sector(dmc->cache_dev->bdev->bd_inode->i_size);
cache_size = dmc->size * dmc->block_size;
if (cache_size > dev_size) {
DMERR("Requested cache size exeeds the cache device's capacity" \
"(%lu>%lu)",
cache_size, dev_size);
return 1;
}
order = dmc->size * sizeof(struct cacheblock);
DMINFO("Allocate %luKB (%luB per) mem for %lu-entry cache" \
"(capacity:%luMB, associativity:%u, block size:%u " \
"sectors(%uKB))",
order >> 10, sizeof(struct cacheblock), dmc->size,
cache_size >> (20-SECTOR_SHIFT), dmc->assoc, dmc->block_size,
dmc->block_size >> (10-SECTOR_SHIFT));
dmc->cache = (struct cacheblock *)vmalloc(order);
if (!dmc->cache) {
DMERR("flashcache_writethrough_create: Unable to allocate cache md");
return 1;
}
/* Initialize the cache structs */
for (i = 0; i < dmc->size ; i++) {
dmc->cache[i].dbn = 0;
#ifdef FLASHCACHE_DO_CHECKSUMS
dmc->cache[i].checksum = 0;
#endif
dmc->cache[i].cache_state = INVALID;
dmc->cache[i].nr_queued = 0;
}
dmc->md_blocks = 0;
return 0;
}
static int
flashcache_writeback_create(struct cache_c *dmc, int force)
{
struct flash_cacheblock *meta_data_cacheblock, *next_ptr;
struct flash_superblock *header;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,26)
struct io_region where;
#else
struct dm_io_region where;
#endif
int i, j, error;
sector_t cache_size, dev_size;
sector_t order;
int sectors_written = 0, sectors_expected = 0; /* debug */
int slots_written = 0; /* How many cache slots did we fill in this MD io block ? */
header = (struct flash_superblock *)vmalloc(MD_BLOCK_BYTES(dmc));
if (!header) {
DMERR("flashcache_writeback_create: Unable to allocate sector");
return 1;
}
where.bdev = dmc->cache_dev->bdev;
where.sector = 0;
where.count = dmc->md_block_size;
error = flashcache_dm_io_sync_vm(dmc, &where, READ, header);
if (error) {
vfree((void *)header);
DMERR("flashcache_writeback_create: Could not read cache superblock %lu error %d !",
where.sector, error);
return 1;
}
if (!force &&
((header->cache_sb_state == CACHE_MD_STATE_DIRTY) ||
(header->cache_sb_state == CACHE_MD_STATE_CLEAN) ||
(header->cache_sb_state == CACHE_MD_STATE_FASTCLEAN))) {
vfree((void *)header);
DMERR("flashcache_writeback_create: Existing Cache Detected, use force to re-create");
return 1;
}
/* Compute the size of the metadata, including header.
Note dmc->size is in raw sectors */
dmc->md_blocks = INDEX_TO_MD_BLOCK(dmc, dmc->size / dmc->block_size) + 1 + 1;
dmc->size -= dmc->md_blocks * MD_SECTORS_PER_BLOCK(dmc); /* total sectors available for cache */
dmc->size /= dmc->block_size;
dmc->size = (dmc->size / dmc->assoc) * dmc->assoc;
/* Recompute since dmc->size was possibly trunc'ed down */
dmc->md_blocks = INDEX_TO_MD_BLOCK(dmc, dmc->size) + 1 + 1;
DMINFO("flashcache_writeback_create: md_blocks = %d, md_sectors = %d\n",
dmc->md_blocks, dmc->md_blocks * MD_SECTORS_PER_BLOCK(dmc));
dev_size = to_sector(dmc->cache_dev->bdev->bd_inode->i_size);
cache_size = dmc->md_blocks * MD_SECTORS_PER_BLOCK(dmc) + (dmc->size * dmc->block_size);
if (cache_size > dev_size) {
DMERR("Requested cache size exceeds the cache device's capacity" \
"(%lu>%lu)",
cache_size, dev_size);
vfree((void *)header);
return 1;
}
order = dmc->size * sizeof(struct cacheblock);
DMINFO("Allocate %luKB (%luB per) mem for %lu-entry cache" \
"(capacity:%luMB, associativity:%u, block size:%u " \
"sectors(%uKB))",
order >> 10, sizeof(struct cacheblock), dmc->size,
cache_size >> (20-SECTOR_SHIFT), dmc->assoc, dmc->block_size,
dmc->block_size >> (10-SECTOR_SHIFT));
dmc->cache = (struct cacheblock *)vmalloc(order);
if (!dmc->cache) {
vfree((void *)header);
DMERR("flashcache_writeback_create: Unable to allocate cache md");
return 1;
}
/* Initialize the cache structs */
for (i = 0; i < dmc->size ; i++) {
dmc->cache[i].dbn = 0;
#ifdef FLASHCACHE_DO_CHECKSUMS
dmc->cache[i].checksum = 0;
#endif
dmc->cache[i].cache_state = INVALID;
dmc->cache[i].nr_queued = 0;
}
meta_data_cacheblock = (struct flash_cacheblock *)vmalloc(METADATA_IO_BLOCKSIZE);
if (!meta_data_cacheblock) {
DMERR("flashcache_writeback_create: Unable to allocate memory");
DMERR("flashcache_writeback_create: Could not write out cache metadata !");
return 1;
}
where.sector = MD_SECTORS_PER_BLOCK(dmc);
slots_written = 0;
next_ptr = meta_data_cacheblock;
j = MD_SLOTS_PER_BLOCK(dmc);
for (i = 0 ; i < dmc->size ; i++) {
next_ptr->dbn = dmc->cache[i].dbn;
#ifdef FLASHCACHE_DO_CHECKSUMS
next_ptr->checksum = dmc->cache[i].checksum;
#endif
next_ptr->cache_state = dmc->cache[i].cache_state &
(INVALID | VALID | DIRTY);
next_ptr++;
slots_written++;
j--;
if (j == 0) {
/*
* Filled the block, write and goto the next metadata block.
*/
if (slots_written == MD_SLOTS_PER_BLOCK(dmc) * METADATA_IO_NUM_BLOCKS(dmc)) {
/*
* Wrote out an entire metadata IO block, write the block to the ssd.
*/
where.count = (slots_written / MD_SLOTS_PER_BLOCK(dmc)) * MD_SECTORS_PER_BLOCK(dmc);
slots_written = 0;
sectors_written += where.count; /* debug */
error = flashcache_dm_io_sync_vm(dmc, &where, WRITE,
meta_data_cacheblock);
if (error) {
vfree((void *)header);
vfree((void *)meta_data_cacheblock);
vfree(dmc->cache);
DMERR("flashcache_writeback_create: Could not write cache metadata block %lu error %d !",
where.sector, error);
return 1;
}
where.sector += where.count; /* Advance offset */
}
/* Move next slot pointer into next metadata block */
next_ptr = (struct flash_cacheblock *)
((caddr_t)meta_data_cacheblock + ((slots_written / MD_SLOTS_PER_BLOCK(dmc)) * MD_BLOCK_BYTES(dmc)));
j = MD_SLOTS_PER_BLOCK(dmc);
}
}
if (next_ptr != meta_data_cacheblock) {
/* Write the remaining last blocks out */
VERIFY(slots_written > 0);
where.count = (slots_written / MD_SLOTS_PER_BLOCK(dmc)) * MD_SECTORS_PER_BLOCK(dmc);
if (slots_written % MD_SLOTS_PER_BLOCK(dmc))
where.count += MD_SECTORS_PER_BLOCK(dmc);
sectors_written += where.count;
error = flashcache_dm_io_sync_vm(dmc, &where, WRITE, meta_data_cacheblock);
if (error) {
vfree((void *)header);
vfree((void *)meta_data_cacheblock);
vfree(dmc->cache);
DMERR("flashcache_writeback_create: Could not write cache metadata block %lu error %d !",
where.sector, error);
return 1;
}
}
/* Debug Tests */
sectors_expected = (dmc->size / MD_SLOTS_PER_BLOCK(dmc)) * MD_SECTORS_PER_BLOCK(dmc);
if (dmc->size % MD_SLOTS_PER_BLOCK(dmc))
sectors_expected += MD_SECTORS_PER_BLOCK(dmc);
if (sectors_expected != sectors_written) {
printk("flashcache_writeback_create" "Sector Mismatch ! sectors_expected=%d, sectors_written=%d\n",
sectors_expected, sectors_written);
panic("flashcache_writeback_create: sector mismatch\n");
}
vfree((void *)meta_data_cacheblock);
/* Write the header */
header->cache_sb_state = CACHE_MD_STATE_DIRTY;
header->block_size = dmc->block_size;
header->md_block_size = dmc->md_block_size;
header->size = dmc->size;
header->assoc = dmc->assoc;
strncpy(header->disk_devname, dmc->disk_devname, DEV_PATHLEN);
strncpy(header->cache_devname, dmc->dm_vdevname, DEV_PATHLEN);
header->cache_devsize = to_sector(dmc->cache_dev->bdev->bd_inode->i_size);
header->disk_devsize = to_sector(dmc->disk_dev->bdev->bd_inode->i_size);
dmc->on_ssd_version = header->cache_version = FLASHCACHE_VERSION;
where.sector = 0;
where.count = dmc->md_block_size;
printk("flashcache-dbg: cachedev check - %s %s", header->cache_devname,
dmc->dm_vdevname);
error = flashcache_dm_io_sync_vm(dmc, &where, WRITE, header);
if (error) {
vfree((void *)header);
vfree(dmc->cache);
DMERR("flashcache_writeback_create: Could not write cache superblock %lu error %d !",
where.sector, error);
return 1;
}
vfree((void *)header);
return 0;
}
static int
flashcache_writeback_load(struct cache_c *dmc)
{
struct flash_cacheblock *meta_data_cacheblock, *next_ptr;
struct flash_superblock *header;
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,26)
struct io_region where;
#else
struct dm_io_region where;
#endif
int i, j;
u_int64_t size, slots_read;
int clean_shutdown;
int dirty_loaded = 0;
sector_t order, data_size;
int num_valid = 0;
int error;
int sectors_read = 0, sectors_expected = 0; /* Debug */
/*
* We don't know what the preferred block size is, just read off
* the default md blocksize.
*/
header = (struct flash_superblock *)vmalloc(DEFAULT_MD_BLOCK_SIZE);
if (!header) {
DMERR("flashcache_writeback_load: Unable to allocate memory");
return 1;
}
where.bdev = dmc->cache_dev->bdev;
where.sector = 0;
where.count = DEFAULT_MD_BLOCK_SIZE;
error = flashcache_dm_io_sync_vm(dmc, &where, READ, header);
if (error) {
vfree((void *)header);
DMERR("flashcache_writeback_load: Could not read cache superblock %lu error %d!",
where.sector, error);
return 1;
}
if (header->cache_version == 1) {
/* Backwards compatibility, md was 512 bytes always in V1.0 */
header->md_block_size = 1;
} else if (header->cache_version > FLASHCACHE_VERSION) {
vfree((void *)header);
DMERR("flashcache_writeback_load: Unknown version %d found in superblock!", header->cache_version);
return 1;
}
dmc->on_ssd_version = header->cache_version;
DPRINTK("Loaded cache conf: version(%d), block size(%u), md block size(%u), cache size(%llu), " \
"associativity(%u)",
header->cache_version, header->block_size, header->md_block_size, header->size,
header->assoc);
if (!((header->cache_sb_state == CACHE_MD_STATE_DIRTY) ||
(header->cache_sb_state == CACHE_MD_STATE_CLEAN) ||
(header->cache_sb_state == CACHE_MD_STATE_FASTCLEAN))) {
vfree((void *)header);
DMERR("flashcache_writeback_load: Corrupt Cache Superblock");
return 1;
}
if (header->cache_sb_state == CACHE_MD_STATE_DIRTY) {
DMINFO("Unclean Shutdown Detected");
printk(KERN_ALERT "Only DIRTY blocks exist in cache");
clean_shutdown = 0;
} else if (header->cache_sb_state == CACHE_MD_STATE_CLEAN) {
DMINFO("Slow (clean) Shutdown Detected");
printk(KERN_ALERT "Only CLEAN blocks exist in cache");
clean_shutdown = 1;
} else {
DMINFO("Fast (clean) Shutdown Detected");
printk(KERN_ALERT "Both CLEAN and DIRTY blocks exist in cache");
clean_shutdown = 1;
}
dmc->block_size = header->block_size;
dmc->md_block_size = header->md_block_size;
dmc->block_shift = ffs(dmc->block_size) - 1;
dmc->block_mask = dmc->block_size - 1;
dmc->size = header->size;
dmc->assoc = header->assoc;
dmc->assoc_shift = ffs(dmc->assoc) - 1;
dmc->md_blocks = INDEX_TO_MD_BLOCK(dmc, dmc->size) + 1 + 1;
DMINFO("flashcache_writeback_load: md_blocks = %d, md_sectors = %d, md_block_size = %d\n",
dmc->md_blocks, dmc->md_blocks * MD_SECTORS_PER_BLOCK(dmc), dmc->md_block_size);
data_size = dmc->size * dmc->block_size;
order = dmc->size * sizeof(struct cacheblock);
DMINFO("Allocate %luKB (%ldB per) mem for %lu-entry cache" \
"(capacity:%luMB, associativity:%u, block size:%u " \
"sectors(%uKB))",
order >> 10, sizeof(struct cacheblock), dmc->size,
(dmc->md_blocks * MD_SECTORS_PER_BLOCK(dmc) + data_size) >> (20-SECTOR_SHIFT),
dmc->assoc, dmc->block_size,
dmc->block_size >> (10-SECTOR_SHIFT));
dmc->cache = (struct cacheblock *)vmalloc(order);
if (!dmc->cache) {
DMERR("load_metadata: Unable to allocate memory");
vfree((void *)header);
return 1;
}
/* Read the metadata in large blocks and populate incore state */
meta_data_cacheblock = (struct flash_cacheblock *)vmalloc(METADATA_IO_BLOCKSIZE);
if (!meta_data_cacheblock) {
vfree((void *)header);
vfree(dmc->cache);
DMERR("flashcache_writeback_load: Unable to allocate memory");
return 1;
}
where.sector = MD_SECTORS_PER_BLOCK(dmc);
size = dmc->size;
i = 0;
while (size > 0) {
slots_read = min(size, (u_int64_t)(MD_SLOTS_PER_BLOCK(dmc) * METADATA_IO_NUM_BLOCKS(dmc)));
if (slots_read % MD_SLOTS_PER_BLOCK(dmc))
where.count = (1 + (slots_read / MD_SLOTS_PER_BLOCK(dmc))) * MD_SECTORS_PER_BLOCK(dmc);
else
where.count = (slots_read / MD_SLOTS_PER_BLOCK(dmc)) * MD_SECTORS_PER_BLOCK(dmc);
sectors_read += where.count; /* Debug */
error = flashcache_dm_io_sync_vm(dmc, &where, READ, meta_data_cacheblock);
if (error) {
vfree((void *)header);
vfree(dmc->cache);
vfree((void *)meta_data_cacheblock);
DMERR("flashcache_writeback_load: Could not read cache metadata block %lu error %d !",
where.sector, error);
return 1;
}
where.sector += where.count;
next_ptr = meta_data_cacheblock;
for (j = 0 ; j < slots_read ; j++) {
/*
* XXX - Now that we force each on-ssd metadata cache slot to be a ^2, where
* we are guaranteed that the slots will exactly fit within a sector (and
* a metadata block), we can simplify this logic. We don't need this next test.
*/
if ((j % MD_SLOTS_PER_BLOCK(dmc)) == 0) {
/* Move onto next block */
next_ptr = (struct flash_cacheblock *)
((caddr_t)meta_data_cacheblock + MD_BLOCK_BYTES(dmc) * (j / MD_SLOTS_PER_BLOCK(dmc)));
}
dmc->cache[i].nr_queued = 0;
/*
* If unclean shutdown, only the DIRTY blocks are loaded.
*/
if (clean_shutdown || (next_ptr->cache_state & DIRTY)) {
if (next_ptr->cache_state & DIRTY)
dirty_loaded++;
dmc->cache[i].cache_state = next_ptr->cache_state;
VERIFY((dmc->cache[i].cache_state & (VALID | INVALID))
!= (VALID | INVALID));
if (dmc->cache[i].cache_state & VALID)
num_valid++;
dmc->cache[i].dbn = next_ptr->dbn;
#ifdef FLASHCACHE_DO_CHECKSUMS
if (clean_shutdown)
dmc->cache[i].checksum = next_ptr->checksum;
else {
error = flashcache_read_compute_checksum(dmc, i, block);
if (error) {
vfree((void *)header);
vfree(dmc->cache);
vfree((void *)meta_data_cacheblock);
DMERR("flashcache_writeback_load: Could not read cache metadata block %lu error %d !",
dmc->cache[i].dbn, error);
return 1;
}
}
#endif
} else {
dmc->cache[i].cache_state = INVALID;
dmc->cache[i].dbn = 0;
#ifdef FLASHCACHE_DO_CHECKSUMS
dmc->cache[i].checksum = 0;
#endif
}
next_ptr++;
i++;
}
size -= slots_read;
}
/* Debug Tests */
sectors_expected = (dmc->size / MD_SLOTS_PER_BLOCK(dmc)) * MD_SECTORS_PER_BLOCK(dmc);
if (dmc->size % MD_SLOTS_PER_BLOCK(dmc))
sectors_expected += MD_SECTORS_PER_BLOCK(dmc);
if (sectors_expected != sectors_read) {
printk("flashcache_writeback_load" "Sector Mismatch ! sectors_expected=%d, sectors_read=%d\n",
sectors_expected, sectors_read);
panic("flashcache_writeback_load: sector mismatch\n");
}
vfree((void *)meta_data_cacheblock);
/*
* For writing the superblock out, use the preferred blocksize that
* we read from the superblock above.
*/
if (DEFAULT_MD_BLOCK_SIZE != dmc->md_block_size) {
vfree((void *)header);
header = (struct flash_superblock *)vmalloc(MD_BLOCK_BYTES(dmc));
if (!header) {
DMERR("flashcache_writeback_load: Unable to allocate memory");
return 1;
}
}
/* Before we finish loading, we need to dirty the superblock and
write it out */
header->size = dmc->size;
header->block_size = dmc->block_size;
header->md_block_size = dmc->md_block_size;
header->assoc = dmc->assoc;
header->cache_sb_state = CACHE_MD_STATE_DIRTY;
strncpy(header->disk_devname, dmc->disk_devname, DEV_PATHLEN);
strncpy(header->cache_devname, dmc->dm_vdevname, DEV_PATHLEN);
header->cache_devsize = to_sector(dmc->cache_dev->bdev->bd_inode->i_size);
header->disk_devsize = to_sector(dmc->disk_dev->bdev->bd_inode->i_size);
header->cache_version = dmc->on_ssd_version;
where.sector = 0;
where.count = dmc->md_block_size;
error = flashcache_dm_io_sync_vm(dmc, &where, WRITE, header);
if (error) {
vfree((void *)header);
vfree(dmc->cache);
DMERR("flashcache_writeback_load: Could not write cache superblock %lu error %d !",
where.sector, error);
return 1;
}
vfree((void *)header);
DMINFO("flashcache_writeback_load: Cache metadata loaded from disk with %d valid %d DIRTY blocks",
num_valid, dirty_loaded);
return 0;
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
static void
flashcache_clean_all_sets(void *data)
{
struct cache_c *dmc = (struct cache_c *)data;
#else
static void
flashcache_clean_all_sets(struct work_struct *work)
{
struct cache_c *dmc = container_of(work, struct cache_c,
delayed_clean.work);
#endif
int i;
for (i = 0 ; i < dmc->num_sets ; i++)
flashcache_clean_set(dmc, i);
}
static int inline
flashcache_get_dev(struct dm_target *ti, char *pth, struct dm_dev **dmd,
char *dmc_dname, sector_t tilen)
{
int rc;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,34)
rc = dm_get_device(ti, pth,
dm_table_get_mode(ti->table), dmd);
#else
#if defined(RHEL_MAJOR) && RHEL_MAJOR == 6
rc = dm_get_device(ti, pth,
dm_table_get_mode(ti->table), dmd);
#else
rc = dm_get_device(ti, pth, 0, tilen,
dm_table_get_mode(ti->table), dmd);
#endif
#endif
if (!rc)
strncpy(dmc_dname, pth, DEV_PATHLEN);
return rc;
}
/*
* Construct a cache mapping.
* arg[0]: path to source device
* arg[1]: path to cache device
* arg[2]: md virtual device name
* arg[3]: cache mode (from flashcache.h)
* arg[4]: cache persistence (if set, cache conf is loaded from disk)
* Cache configuration parameters (if not set, default values are used.
* arg[5]: cache block size (in sectors)
* arg[6]: cache size (in blocks)
* arg[7]: cache associativity
* arg[8]: md block size (in sectors)
*/
int
flashcache_ctr(struct dm_target *ti, unsigned int argc, char **argv)
{
struct cache_c *dmc;
sector_t i, order;
int r = -EINVAL;
int persistence = 0;
if (argc < 3) {
ti->error = "flashcache: Need at least 3 arguments";
goto bad;
}
dmc = kzalloc(sizeof(*dmc), GFP_KERNEL);
if (dmc == NULL) {
ti->error = "flashcache: Failed to allocate cache context";
r = ENOMEM;
goto bad;
}
dmc->tgt = ti;
if (flashcache_get_dev(ti, argv[0], &dmc->disk_dev,
dmc->disk_devname, ti->len)) {
ti->error = "flashcache: Disk device lookup failed";
goto bad1;
}
if (flashcache_get_dev(ti, argv[1], &dmc->cache_dev,
dmc->cache_devname, 0)) {
ti->error = "flashcache: Cache device lookup failed";
goto bad2;
}
if (sscanf(argv[2], "%s", (char *)&dmc->dm_vdevname) != 1) {
ti->error = "flashcache: Virtual device name lookup failed";
goto bad3;
}
r = flashcache_kcached_init(dmc);
if (r) {
ti->error = "Failed to initialize kcached";
goto bad3;
}
if (sscanf(argv[3], "%u", &dmc->cache_mode) != 1) {
ti->error = "flashcache: sscanf failed, invalid cache mode";
r = -EINVAL;
goto bad3;
}
if (dmc->cache_mode < FLASHCACHE_WRITE_BACK ||
dmc->cache_mode > FLASHCACHE_WRITE_AROUND) {
DMERR("cache_mode = %d", dmc->cache_mode);
ti->error = "flashcache: Invalid cache mode";
r = -EINVAL;
goto bad3;
}
/*
* XXX - Persistence is totally ignored for write through and write around.
* Maybe this should really be moved to the end of the param list ?
*/
if (dmc->cache_mode == FLASHCACHE_WRITE_BACK) {
if (argc >= 5) {
if (sscanf(argv[4], "%u", &persistence) != 1) {
ti->error = "flashcache: sscanf failed, invalid cache persistence";
r = -EINVAL;
goto bad3;
}
if (persistence < CACHE_RELOAD || persistence > CACHE_FORCECREATE) {
DMERR("persistence = %d", persistence);
ti->error = "flashcache: Invalid cache persistence";
r = -EINVAL;
goto bad3;
}
}
if (persistence == CACHE_RELOAD) {
if (flashcache_writeback_load(dmc)) {
ti->error = "flashcache: Cache reload failed";
r = -EINVAL;
goto bad3;
}
goto init; /* Skip reading cache parameters from command line */
}
} else
persistence = CACHE_CREATE;
if (argc >= 6) {
if (sscanf(argv[5], "%u", &dmc->block_size) != 1) {
ti->error = "flashcache: Invalid block size";
r = -EINVAL;
goto bad3;
}
if (!dmc->block_size || (dmc->block_size & (dmc->block_size - 1))) {
ti->error = "flashcache: Invalid block size";
r = -EINVAL;
goto bad3;
}
}
if (!dmc->block_size)
dmc->block_size = DEFAULT_BLOCK_SIZE;
dmc->block_shift = ffs(dmc->block_size) - 1;
dmc->block_mask = dmc->block_size - 1;
/* dmc->size is specified in sectors here, and converted to blocks later */
if (argc >= 7) {
if (sscanf(argv[6], "%lu", &dmc->size) != 1) {
ti->error = "flashcache: Invalid cache size";
r = -EINVAL;
goto bad3;
}
}
if (!dmc->size)
dmc->size = to_sector(dmc->cache_dev->bdev->bd_inode->i_size);
if (argc >= 8) {
if (sscanf(argv[7], "%u", &dmc->assoc) != 1) {
ti->error = "flashcache: Invalid cache associativity";
r = -EINVAL;
goto bad3;
}
if (!dmc->assoc || (dmc->assoc & (dmc->assoc - 1)) ||
dmc->assoc > FLASHCACHE_MAX_ASSOC ||
dmc->assoc < FLASHCACHE_MIN_ASSOC ||
dmc->size < dmc->assoc) {
ti->error = "flashcache: Invalid cache associativity";
r = -EINVAL;
goto bad3;
}
}
if (!dmc->assoc)
dmc->assoc = DEFAULT_CACHE_ASSOC;
dmc->assoc_shift = ffs(dmc->assoc) - 1;
if (dmc->cache_mode == FLASHCACHE_WRITE_BACK) {
if (argc >= 9) {
if (sscanf(argv[8], "%u", &dmc->md_block_size) != 1) {
ti->error = "flashcache: Invalid metadata block size";
r = -EINVAL;
goto bad3;
}
if (!dmc->md_block_size || (dmc->md_block_size & (dmc->md_block_size - 1)) ||
dmc->md_block_size > FLASHCACHE_MAX_MD_BLOCK_SIZE) {
ti->error = "flashcache: Invalid metadata block size";
r = -EINVAL;
goto bad3;
}
if (dmc->assoc <
(dmc->md_block_size * 512 / sizeof(struct flash_cacheblock))) {