/*
* Copyright (C) 2015 Shaohua Li <shli@fb.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*
*/
#include <linux/kernel.h>
#include <linux/wait.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/raid/md_p.h>
#include <linux/crc32.h>
#include <linux/random.h>
#include "md.h"
#include "raid5.h"
/*
* metadata/data stored in disk with 4k size unit (a block) regardless
* underneath hardware sector size. only works with PAGE_SIZE == 4096
*/
#define BLOCK_SECTORS (8)
struct r5l_log {
struct md_rdev *rdev;
u32 uuid_checksum;
sector_t device_size; /* log device size, round to
* BLOCK_SECTORS */
sector_t last_checkpoint; /* log tail. where recovery scan
* starts from */
u64 last_cp_seq; /* log tail sequence */
sector_t log_start; /* log head. where new data appends */
u64 seq; /* log head sequence */
struct mutex io_mutex;
struct r5l_io_unit *current_io; /* current io_unit accepting new data */
spinlock_t io_list_lock;
struct list_head running_ios; /* io_units which are still running,
* and have not yet been completely
* written to the log */
struct list_head io_end_ios; /* io_units which have been completely
* written to the log but not yet written
* to the RAID */
struct kmem_cache *io_kc;
struct list_head no_space_stripes; /* pending stripes, log has no space */
spinlock_t no_space_stripes_lock;
};
/*
* an IO range starts from a meta data block and end at the next meta data
* block. The io unit's the meta data block tracks data/parity followed it. io
* unit is written to log disk with normal write, as we always flush log disk
* first and then start move data to raid disks, there is no requirement to
* write io unit with FLUSH/FUA
*/
struct r5l_io_unit {
struct r5l_log *log;
struct page *meta_page; /* store meta block */
int meta_offset; /* current offset in meta_page */
struct bio_list bios;
atomic_t pending_io; /* pending bios not written to log yet */
struct bio *current_bio;/* current_bio accepting new data */
atomic_t pending_stripe;/* how many stripes not flushed to raid */
u64 seq; /* seq number of the metablock */
sector_t log_start; /* where the io_unit starts */
sector_t log_end; /* where the io_unit ends */
struct list_head log_sibling; /* log->running_ios */
struct list_head stripe_list; /* stripes added to the io_unit */
int state;
wait_queue_head_t wait_state;
};
/* r5l_io_unit state */
enum r5l_io_unit_state {
IO_UNIT_RUNNING = 0, /* accepting new IO */
IO_UNIT_IO_START = 1, /* io_unit bio start writing to log,
* don't accepting new bio */
IO_UNIT_IO_END = 2, /* io_unit bio finish writing to log */
IO_UNIT_STRIPE_START = 3, /* stripes of io_unit are flushing to raid */
IO_UNIT_STRIPE_END = 4, /* stripes data finished writing to raid */
};
static sector_t r5l_ring_add(struct r5l_log *log, sector_t start, sector_t inc)
{
start += inc;
if (start >= log->device_size)
start = start - log->device_size;
return start;
}
static sector_t r5l_ring_distance(struct r5l_log *log, sector_t start,
sector_t end)
{
if (end >= start)
return end - start;
else
return end + log->device_size - start;
}
static bool r5l_has_free_space(struct r5l_log *log, sector_t size)
{
sector_t used_size;
used_size = r5l_ring_distance(log, log->last_checkpoint,
log->log_start);
return log->device_size > used_size + size;
}
static struct r5l_io_unit *r5l_alloc_io_unit(struct r5l_log *log)
{
struct r5l_io_unit *io;
/* We can't handle memory allocate failure so far */
gfp_t gfp = GFP_NOIO | __GFP_NOFAIL;
io = kmem_cache_zalloc(log->io_kc, gfp);
io->log = log;
io->meta_page = alloc_page(gfp | __GFP_ZERO);
bio_list_init(&io->bios);
INIT_LIST_HEAD(&io->log_sibling);
INIT_LIST_HEAD(&io->stripe_list);
io->state = IO_UNIT_RUNNING;
init_waitqueue_head(&io->wait_state);
return io;
}
static void r5l_free_io_unit(struct r5l_log *log, struct r5l_io_unit *io)
{
__free_page(io->meta_page);
kmem_cache_free(log->io_kc, io);
}
static void r5l_move_io_unit_list(struct list_head *from, struct list_head *to,
enum r5l_io_unit_state state)
{
struct r5l_io_unit *io;
while (!list_empty(from)) {
io = list_first_entry(from, struct r5l_io_unit, log_sibling);
/* don't change list order */
if (io->state >= state)
list_move_tail(&io->log_sibling, to);
else
break;
}
}
static void r5l_wake_reclaim(struct r5l_log *log, sector_t space);
static void __r5l_set_io_unit_state(struct r5l_io_unit *io,
enum r5l_io_unit_state state)
{
struct r5l_log *log = io->log;
if (WARN_ON(io->state >= state))
return;
io->state = state;
if (state == IO_UNIT_IO_END)
r5l_move_io_unit_list(&log->running_ios, &log->io_end_ios,
IO_UNIT_IO_END);
wake_up(&io->wait_state);
}
static void r5l_set_io_unit_state(struct r5l_io_unit *io,
enum r5l_io_unit_state state)
{
struct r5l_log *log = io->log;
unsigned long flags;
spin_lock_irqsave(&log->io_list_lock, flags);
__r5l_set_io_unit_state(io, state);
spin_unlock_irqrestore(&log->io_list_lock, flags);
}
/* XXX: totally ignores I/O errors */
static void r5l_log_endio(struct bio *bio)
{
struct r5l_io_unit *io = bio->bi_private;
struct r5l_log *log = io->log;
bio_put(bio);
if (!atomic_dec_and_test(&io->pending_io))
return;
r5l_set_io_unit_state(io, IO_UNIT_IO_END);
md_wakeup_thread(log->rdev->mddev->thread);
}
static void r5l_submit_current_io(struct r5l_log *log)
{
struct r5l_io_unit *io = log->current_io;
struct r5l_meta_block *block;
struct bio *bio;
u32 crc;
if (!io)
return;
block = page_address(io->meta_page);
block->meta_size = cpu_to_le32(io->meta_offset);
crc = crc32_le(log->uuid_checksum, (void *)block, PAGE_SIZE);
block->checksum = cpu_to_le32(crc);
log->current_io = NULL;
r5l_set_io_unit_state(io, IO_UNIT_IO_START);
while ((bio = bio_list_pop(&io->bios))) {
/* all IO must start from rdev->data_offset */
bio->bi_iter.bi_sector += log->rdev->data_offset;
submit_bio(WRITE, bio);
}
}
static struct r5l_io_unit *r5l_new_meta(struct r5l_log *log)
{
struct r5l_io_unit *io;
struct r5l_meta_block *block;
struct bio *bio;
io = r5l_alloc_io_unit(log);
block = page_address(io->meta_page);
block->magic = cpu_to_le32(R5LOG_MAGIC);
block->version = R5LOG_VERSION;
block->seq = cpu_to_le64(log->seq);
block->position = cpu_to_le64(log->log_start);
io->log_start = log->log_start;
io->meta_offset = sizeof(struct r5l_meta_block);
io->seq = log->seq;
bio = bio_kmalloc(GFP_NOIO | __GFP_NOFAIL, BIO_MAX_PAGES);
io->current_bio = bio;
bio->bi_rw = WRITE;
bio->bi_bdev = log->rdev->bdev;
bio->bi_iter.bi_sector = log->log_start;
bio_add_page(bio, io->meta_page, PAGE_SIZE, 0);
bio->bi_end_io = r5l_log_endio;
bio->bi_private = io;
bio_list_add(&io->bios, bio);
atomic_inc(&io->pending_io);
log->seq++;
log->log_start = r5l_ring_add(log, log->log_start, BLOCK_SECTORS);
io->log_end = log->log_start;
/* current bio hit disk end */
if (log->log_start == 0)
io->current_bio = NULL;
spin_lock_irq(&log->io_list_lock);
list_add_tail(&io->log_sibling, &log->running_ios);
spin_unlock_irq(&log->io_list_lock);
return io;
}
static int r5l_get_meta(struct r5l_log *log, unsigned int payload_size)
{
struct r5l_io_unit *io;
io = log->current_io;
if (io && io->meta_offset + payload_size > PAGE_SIZE)
r5l_submit_current_io(log);
io = log->current_io;
if (io)
return 0;
log->current_io = r5l_new_meta(log);
return 0;
}
static void r5l_append_payload_meta(struct r5l_log *log, u16 type,
sector_t location,
u32 checksum1, u32 checksum2,
bool checksum2_valid)
{
struct r5l_io_unit *io = log->current_io;
struct r5l_payload_data_parity *payload;
payload = page_address(io->meta_page) + io->meta_offset;
payload->header.type = cpu_to_le16(type);
payload->header.flags = cpu_to_le16(0);
payload->size = cpu_to_le32((1 + !!checksum2_valid) <<
(PAGE_SHIFT - 9));
payload->location = cpu_to_le64(location);
payload->checksum[0] = cpu_to_le32(checksum1);
if (checksum2_valid)
payload->checksum[1] = cpu_to_le32(checksum2);
io->meta_offset += sizeof(struct r5l_payload_data_parity) +
sizeof(__le32) * (1 + !!checksum2_valid);
}
static void r5l_append_payload_page(struct r5l_log *log, struct page *page)
{
struct r5l_io_unit *io = log->current_io;
alloc_bio:
if (!io->current_bio) {
struct bio *bio;
bio = bio_kmalloc(GFP_NOIO | __GFP_NOFAIL, BIO_MAX_PAGES);
bio->bi_rw = WRITE;
bio->bi_bdev = log->rdev->bdev;
bio->bi_iter.bi_sector = log->log_start;
bio->bi_end_io = r5l_log_endio;
bio->bi_private = io;
bio_list_add(&io->bios, bio);
atomic_inc(&io->pending_io);
io->current_bio = bio;
}
if (!bio_add_page(io->current_bio, page, PAGE_SIZE, 0)) {
io->current_bio = NULL;
goto alloc_bio;
}
log->log_start = r5l_ring_add(log, log->log_start,
BLOCK_SECTORS);
/* current bio hit disk end */
if (log->log_start == 0)
io->current_bio = NULL;
io->log_end = log->log_start;
}
static void r5l_log_stripe(struct r5l_log *log, struct stripe_head *sh,
int data_pages, int parity_pages)
{
int i;
int meta_size;
struct r5l_io_unit *io;
meta_size =
((sizeof(struct r5l_payload_data_parity) + sizeof(__le32))
* data_pages) +
sizeof(struct r5l_payload_data_parity) +
sizeof(__le32) * parity_pages;
r5l_get_meta(log, meta_size);
io = log->current_io;
for (i = 0; i < sh->disks; i++) {
if (!test_bit(R5_Wantwrite, &sh->dev[i].flags))
continue;
if (i == sh->pd_idx || i == sh->qd_idx)
continue;
r5l_append_payload_meta(log, R5LOG_PAYLOAD_DATA,
raid5_compute_blocknr(sh, i, 0),
sh->dev[i].log_checksum, 0, false);
r5l_append_payload_page(log, sh->dev[i].page);
}
if (sh->qd_idx >= 0) {
r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY,
sh->sector, sh->dev[sh->pd_idx].log_checksum,
sh->dev[sh->qd_idx].log_checksum, true);
r5l_append_payload_page(log, sh->dev[sh->pd_idx].page);
r5l_append_payload_page(log, sh->dev[sh->qd_idx].page);
} else {
r5l_append_payload_meta(log, R5LOG_PAYLOAD_PARITY,
sh->sector, sh->dev[sh->pd_idx].log_checksum,
0, false);
r5l_append_payload_page(log, sh->dev[sh->pd_idx].page);
}
list_add_tail(&sh->log_list, &io->stripe_list);
atomic_inc(&io->pending_stripe);
sh->log_io = io;
}
/*
* running in raid5d, where reclaim could wait for raid5d too (when it flushes
* data from log to raid disks), so we shouldn't wait for reclaim here
*/
int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh)
{
int write_disks = 0;
int data_pages, parity_pages;
int meta_size;
int reserve;
int i;
if (!log)
return -EAGAIN;
/* Don't support stripe batch */
if (sh->log_io || !test_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags) ||
test_bit(STRIPE_SYNCING, &sh->state)) {
/* the stripe is written to log, we start writing it to raid */
clear_bit(STRIPE_LOG_TRAPPED, &sh->state);
return -EAGAIN;
}
for (i = 0; i < sh->disks; i++) {
void *addr;
if (!test_bit(R5_Wantwrite, &sh->dev[i].flags))
continue;
write_disks++;
/* checksum is already calculated in last run */
if (test_bit(STRIPE_LOG_TRAPPED, &sh->state))
continue;
addr = kmap_atomic(sh->dev[i].page);
sh->dev[i].log_checksum = crc32_le(log->uuid_checksum,
addr, PAGE_SIZE);
kunmap_atomic(addr);
}
parity_pages = 1 + !!(sh->qd_idx >= 0);
data_pages = write_disks - parity_pages;
meta_size =
((sizeof(struct r5l_payload_data_parity) + sizeof(__le32))
* data_pages) +
sizeof(struct r5l_payload_data_parity) +
sizeof(__le32) * parity_pages;
/* Doesn't work with very big raid array */
if (meta_size + sizeof(struct r5l_meta_block) > PAGE_SIZE)
return -EINVAL;
set_bit(STRIPE_LOG_TRAPPED, &sh->state);
atomic_inc(&sh->count);
mutex_lock(&log->io_mutex);
/* meta + data */
reserve = (1 + write_disks) << (PAGE_SHIFT - 9);
if (r5l_has_free_space(log, reserve))
r5l_log_stripe(log, sh, data_pages, parity_pages);
else {
spin_lock(&log->no_space_stripes_lock);
list_add_tail(&sh->log_list, &log->no_space_stripes);
spin_unlock(&log->no_space_stripes_lock);
r5l_wake_reclaim(log, reserve);
}
mutex_unlock(&log->io_mutex);
return 0;
}
void r5l_write_stripe_run(struct r5l_log *log)
{
if (!log)
return;
mutex_lock(&log->io_mutex);
r5l_submit_current_io(log);
mutex_unlock(&log->io_mutex);
}
/* This will run after log space is reclaimed */
static void r5l_run_no_space_stripes(struct r5l_log *log)
{
struct stripe_head *sh;
spin_lock(&log->no_space_stripes_lock);
while (!list_empty(&log->no_space_stripes)) {
sh = list_first_entry(&log->no_space_stripes,
struct stripe_head, log_list);
list_del_init(&sh->log_list);
set_bit(STRIPE_HANDLE, &sh->state);
raid5_release_stripe(sh);
}
spin_unlock(&log->no_space_stripes_lock);
}
static void r5l_wake_reclaim(struct r5l_log *log, sector_t space)
{
/* will implement later */
}
static int r5l_recovery_log(struct r5l_log *log)
{
/* fake recovery */
log->seq = log->last_cp_seq + 1;
log->log_start = r5l_ring_add(log, log->last_checkpoint, BLOCK_SECTORS);
return 0;
}
static void r5l_write_super(struct r5l_log *log, sector_t cp)
{
struct mddev *mddev = log->rdev->mddev;
log->rdev->journal_tail = cp;
set_bit(MD_CHANGE_DEVS, &mddev->flags);
}
static int r5l_load_log(struct r5l_log *log)
{
struct md_rdev *rdev = log->rdev;
struct page *page;
struct r5l_meta_block *mb;
sector_t cp = log->rdev->journal_tail;
u32 stored_crc, expected_crc;
bool create_super = false;
int ret;
/* Make sure it's valid */
if (cp >= rdev->sectors || round_down(cp, BLOCK_SECTORS) != cp)
cp = 0;
page = alloc_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
if (!sync_page_io(rdev, cp, PAGE_SIZE, page, READ, false)) {
ret = -EIO;
goto ioerr;
}
mb = page_address(page);
if (le32_to_cpu(mb->magic) != R5LOG_MAGIC ||
mb->version != R5LOG_VERSION) {
create_super = true;
goto create;
}
stored_crc = le32_to_cpu(mb->checksum);
mb->checksum = 0;
expected_crc = crc32_le(log->uuid_checksum, (void *)mb, PAGE_SIZE);
if (stored_crc != expected_crc) {
create_super = true;
goto create;
}
if (le64_to_cpu(mb->position) != cp) {
create_super = true;
goto create;
}
create:
if (create_super) {
log->last_cp_seq = prandom_u32();
cp = 0;
/*
* Make sure super points to correct address. Log might have
* data very soon. If super hasn't correct log tail address,
* recovery can't find the log
*/
r5l_write_super(log, cp);
} else
log->last_cp_seq = le64_to_cpu(mb->seq);
log->device_size = round_down(rdev->sectors, BLOCK_SECTORS);
log->last_checkpoint = cp;
__free_page(page);
return r5l_recovery_log(log);
ioerr:
__free_page(page);
return ret;
}
int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
{
struct r5l_log *log;
if (PAGE_SIZE != 4096)
return -EINVAL;
log = kzalloc(sizeof(*log), GFP_KERNEL);
if (!log)
return -ENOMEM;
log->rdev = rdev;
log->uuid_checksum = crc32_le(~0, (void *)rdev->mddev->uuid,
sizeof(rdev->mddev->uuid));
mutex_init(&log->io_mutex);
spin_lock_init(&log->io_list_lock);
INIT_LIST_HEAD(&log->running_ios);
log->io_kc = KMEM_CACHE(r5l_io_unit, 0);
if (!log->io_kc)
goto io_kc;
INIT_LIST_HEAD(&log->no_space_stripes);
spin_lock_init(&log->no_space_stripes_lock);
if (r5l_load_log(log))
goto error;
conf->log = log;
return 0;
error:
kmem_cache_destroy(log->io_kc);
io_kc:
kfree(log);
return -EINVAL;
}
void r5l_exit_log(struct r5l_log *log)
{
kmem_cache_destroy(log->io_kc);
kfree(log);
}
