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OpenCloudOS-Kernel/drivers/md/raid5-ppl.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Partial Parity Log for closing the RAID5 write hole
* Copyright (c) 2017, Intel Corporation.
*/
#include <linux/kernel.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/crc32c.h>
#include <linux/async_tx.h>
#include <linux/raid/md_p.h>
#include "md.h"
#include "raid5.h"
#include "raid5-log.h"
/*
* PPL consists of a 4KB header (struct ppl_header) and at least 128KB for
* partial parity data. The header contains an array of entries
* (struct ppl_header_entry) which describe the logged write requests.
* Partial parity for the entries comes after the header, written in the same
* sequence as the entries:
*
* Header
* entry0
* ...
* entryN
* PP data
* PP for entry0
* ...
* PP for entryN
*
* An entry describes one or more consecutive stripe_heads, up to a full
* stripe. The modifed raid data chunks form an m-by-n matrix, where m is the
* number of stripe_heads in the entry and n is the number of modified data
* disks. Every stripe_head in the entry must write to the same data disks.
* An example of a valid case described by a single entry (writes to the first
* stripe of a 4 disk array, 16k chunk size):
*
* sh->sector dd0 dd1 dd2 ppl
* +-----+-----+-----+
* 0 | --- | --- | --- | +----+
* 8 | -W- | -W- | --- | | pp | data_sector = 8
* 16 | -W- | -W- | --- | | pp | data_size = 3 * 2 * 4k
* 24 | -W- | -W- | --- | | pp | pp_size = 3 * 4k
* +-----+-----+-----+ +----+
*
* data_sector is the first raid sector of the modified data, data_size is the
* total size of modified data and pp_size is the size of partial parity for
* this entry. Entries for full stripe writes contain no partial parity
* (pp_size = 0), they only mark the stripes for which parity should be
* recalculated after an unclean shutdown. Every entry holds a checksum of its
* partial parity, the header also has a checksum of the header itself.
*
* A write request is always logged to the PPL instance stored on the parity
* disk of the corresponding stripe. For each member disk there is one ppl_log
* used to handle logging for this disk, independently from others. They are
* grouped in child_logs array in struct ppl_conf, which is assigned to
* r5conf->log_private.
*
* ppl_io_unit represents a full PPL write, header_page contains the ppl_header.
* PPL entries for logged stripes are added in ppl_log_stripe(). A stripe_head
* can be appended to the last entry if it meets the conditions for a valid
* entry described above, otherwise a new entry is added. Checksums of entries
* are calculated incrementally as stripes containing partial parity are being
* added. ppl_submit_iounit() calculates the checksum of the header and submits
* a bio containing the header page and partial parity pages (sh->ppl_page) for
* all stripes of the io_unit. When the PPL write completes, the stripes
* associated with the io_unit are released and raid5d starts writing their data
* and parity. When all stripes are written, the io_unit is freed and the next
* can be submitted.
*
* An io_unit is used to gather stripes until it is submitted or becomes full
* (if the maximum number of entries or size of PPL is reached). Another io_unit
* can't be submitted until the previous has completed (PPL and stripe
* data+parity is written). The log->io_list tracks all io_units of a log
* (for a single member disk). New io_units are added to the end of the list
* and the first io_unit is submitted, if it is not submitted already.
* The current io_unit accepting new stripes is always at the end of the list.
*
* If write-back cache is enabled for any of the disks in the array, its data
* must be flushed before next io_unit is submitted.
*/
#define PPL_SPACE_SIZE (128 * 1024)
struct ppl_conf {
struct mddev *mddev;
/* array of child logs, one for each raid disk */
struct ppl_log *child_logs;
int count;
int block_size; /* the logical block size used for data_sector
* in ppl_header_entry */
u32 signature; /* raid array identifier */
atomic64_t seq; /* current log write sequence number */
struct kmem_cache *io_kc;
mempool_t io_pool;
struct bio_set bs;
struct bio_set flush_bs;
/* used only for recovery */
int recovered_entries;
int mismatch_count;
/* stripes to retry if failed to allocate io_unit */
struct list_head no_mem_stripes;
spinlock_t no_mem_stripes_lock;
unsigned short write_hint;
};
struct ppl_log {
struct ppl_conf *ppl_conf; /* shared between all log instances */
struct md_rdev *rdev; /* array member disk associated with
* this log instance */
struct mutex io_mutex;
struct ppl_io_unit *current_io; /* current io_unit accepting new data
* always at the end of io_list */
spinlock_t io_list_lock;
struct list_head io_list; /* all io_units of this log */
sector_t next_io_sector;
unsigned int entry_space;
bool use_multippl;
bool wb_cache_on;
unsigned long disk_flush_bitmap;
};
#define PPL_IO_INLINE_BVECS 32
struct ppl_io_unit {
struct ppl_log *log;
struct page *header_page; /* for ppl_header */
unsigned int entries_count; /* number of entries in ppl_header */
unsigned int pp_size; /* total size current of partial parity */
u64 seq; /* sequence number of this log write */
struct list_head log_sibling; /* log->io_list */
struct list_head stripe_list; /* stripes added to the io_unit */
atomic_t pending_stripes; /* how many stripes not written to raid */
atomic_t pending_flushes; /* how many disk flushes are in progress */
bool submitted; /* true if write to log started */
/* inline bio and its biovec for submitting the iounit */
struct bio bio;
struct bio_vec biovec[PPL_IO_INLINE_BVECS];
};
struct dma_async_tx_descriptor *
ops_run_partial_parity(struct stripe_head *sh, struct raid5_percpu *percpu,
struct dma_async_tx_descriptor *tx)
{
int disks = sh->disks;
struct page **srcs = percpu->scribble;
int count = 0, pd_idx = sh->pd_idx, i;
struct async_submit_ctl submit;
pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
/*
* Partial parity is the XOR of stripe data chunks that are not changed
* during the write request. Depending on available data
* (read-modify-write vs. reconstruct-write case) we calculate it
* differently.
*/
if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
/*
* rmw: xor old data and parity from updated disks
* This is calculated earlier by ops_run_prexor5() so just copy
* the parity dev page.
*/
srcs[count++] = sh->dev[pd_idx].page;
} else if (sh->reconstruct_state == reconstruct_state_drain_run) {
/* rcw: xor data from all not updated disks */
for (i = disks; i--;) {
struct r5dev *dev = &sh->dev[i];
if (test_bit(R5_UPTODATE, &dev->flags))
srcs[count++] = dev->page;
}
} else {
return tx;
}
init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, tx,
NULL, sh, (void *) (srcs + sh->disks + 2));
if (count == 1)
tx = async_memcpy(sh->ppl_page, srcs[0], 0, 0, PAGE_SIZE,
&submit);
else
tx = async_xor(sh->ppl_page, srcs, 0, count, PAGE_SIZE,
&submit);
return tx;
}
static void *ppl_io_pool_alloc(gfp_t gfp_mask, void *pool_data)
{
struct kmem_cache *kc = pool_data;
struct ppl_io_unit *io;
io = kmem_cache_alloc(kc, gfp_mask);
if (!io)
return NULL;
io->header_page = alloc_page(gfp_mask);
if (!io->header_page) {
kmem_cache_free(kc, io);
return NULL;
}
return io;
}
static void ppl_io_pool_free(void *element, void *pool_data)
{
struct kmem_cache *kc = pool_data;
struct ppl_io_unit *io = element;
__free_page(io->header_page);
kmem_cache_free(kc, io);
}
static struct ppl_io_unit *ppl_new_iounit(struct ppl_log *log,
struct stripe_head *sh)
{
struct ppl_conf *ppl_conf = log->ppl_conf;
struct ppl_io_unit *io;
struct ppl_header *pplhdr;
struct page *header_page;
io = mempool_alloc(&ppl_conf->io_pool, GFP_NOWAIT);
if (!io)
return NULL;
header_page = io->header_page;
memset(io, 0, sizeof(*io));
io->header_page = header_page;
io->log = log;
INIT_LIST_HEAD(&io->log_sibling);
INIT_LIST_HEAD(&io->stripe_list);
atomic_set(&io->pending_stripes, 0);
atomic_set(&io->pending_flushes, 0);
bio_init(&io->bio, io->biovec, PPL_IO_INLINE_BVECS);
pplhdr = page_address(io->header_page);
clear_page(pplhdr);
memset(pplhdr->reserved, 0xff, PPL_HDR_RESERVED);
pplhdr->signature = cpu_to_le32(ppl_conf->signature);
io->seq = atomic64_add_return(1, &ppl_conf->seq);
pplhdr->generation = cpu_to_le64(io->seq);
return io;
}
static int ppl_log_stripe(struct ppl_log *log, struct stripe_head *sh)
{
struct ppl_io_unit *io = log->current_io;
struct ppl_header_entry *e = NULL;
struct ppl_header *pplhdr;
int i;
sector_t data_sector = 0;
int data_disks = 0;
struct r5conf *conf = sh->raid_conf;
pr_debug("%s: stripe: %llu\n", __func__, (unsigned long long)sh->sector);
/* check if current io_unit is full */
if (io && (io->pp_size == log->entry_space ||
io->entries_count == PPL_HDR_MAX_ENTRIES)) {
pr_debug("%s: add io_unit blocked by seq: %llu\n",
__func__, io->seq);
io = NULL;
}
/* add a new unit if there is none or the current is full */
if (!io) {
io = ppl_new_iounit(log, sh);
if (!io)
return -ENOMEM;
spin_lock_irq(&log->io_list_lock);
list_add_tail(&io->log_sibling, &log->io_list);
spin_unlock_irq(&log->io_list_lock);
log->current_io = io;
}
for (i = 0; i < sh->disks; i++) {
struct r5dev *dev = &sh->dev[i];
if (i != sh->pd_idx && test_bit(R5_Wantwrite, &dev->flags)) {
if (!data_disks || dev->sector < data_sector)
data_sector = dev->sector;
data_disks++;
}
}
BUG_ON(!data_disks);
pr_debug("%s: seq: %llu data_sector: %llu data_disks: %d\n", __func__,
io->seq, (unsigned long long)data_sector, data_disks);
pplhdr = page_address(io->header_page);
if (io->entries_count > 0) {
struct ppl_header_entry *last =
&pplhdr->entries[io->entries_count - 1];
struct stripe_head *sh_last = list_last_entry(
&io->stripe_list, struct stripe_head, log_list);
u64 data_sector_last = le64_to_cpu(last->data_sector);
u32 data_size_last = le32_to_cpu(last->data_size);
/*
* Check if we can append the stripe to the last entry. It must
* be just after the last logged stripe and write to the same
* disks. Use bit shift and logarithm to avoid 64-bit division.
*/
if ((sh->sector == sh_last->sector + RAID5_STRIPE_SECTORS(conf)) &&
(data_sector >> ilog2(conf->chunk_sectors) ==
data_sector_last >> ilog2(conf->chunk_sectors)) &&
((data_sector - data_sector_last) * data_disks ==
data_size_last >> 9))
e = last;
}
if (!e) {
e = &pplhdr->entries[io->entries_count++];
e->data_sector = cpu_to_le64(data_sector);
e->parity_disk = cpu_to_le32(sh->pd_idx);
e->checksum = cpu_to_le32(~0);
}
le32_add_cpu(&e->data_size, data_disks << PAGE_SHIFT);
/* don't write any PP if full stripe write */
if (!test_bit(STRIPE_FULL_WRITE, &sh->state)) {
le32_add_cpu(&e->pp_size, PAGE_SIZE);
io->pp_size += PAGE_SIZE;
e->checksum = cpu_to_le32(crc32c_le(le32_to_cpu(e->checksum),
page_address(sh->ppl_page),
PAGE_SIZE));
}
list_add_tail(&sh->log_list, &io->stripe_list);
atomic_inc(&io->pending_stripes);
sh->ppl_io = io;
return 0;
}
int ppl_write_stripe(struct r5conf *conf, struct stripe_head *sh)
{
struct ppl_conf *ppl_conf = conf->log_private;
struct ppl_io_unit *io = sh->ppl_io;
struct ppl_log *log;
if (io || test_bit(STRIPE_SYNCING, &sh->state) || !sh->ppl_page ||
!test_bit(R5_Wantwrite, &sh->dev[sh->pd_idx].flags) ||
!test_bit(R5_Insync, &sh->dev[sh->pd_idx].flags)) {
clear_bit(STRIPE_LOG_TRAPPED, &sh->state);
return -EAGAIN;
}
log = &ppl_conf->child_logs[sh->pd_idx];
mutex_lock(&log->io_mutex);
if (!log->rdev || test_bit(Faulty, &log->rdev->flags)) {
mutex_unlock(&log->io_mutex);
return -EAGAIN;
}
set_bit(STRIPE_LOG_TRAPPED, &sh->state);
clear_bit(STRIPE_DELAYED, &sh->state);
atomic_inc(&sh->count);
if (ppl_log_stripe(log, sh)) {
spin_lock_irq(&ppl_conf->no_mem_stripes_lock);
list_add_tail(&sh->log_list, &ppl_conf->no_mem_stripes);
spin_unlock_irq(&ppl_conf->no_mem_stripes_lock);
}
mutex_unlock(&log->io_mutex);
return 0;
}
static void ppl_log_endio(struct bio *bio)
{
struct ppl_io_unit *io = bio->bi_private;
struct ppl_log *log = io->log;
struct ppl_conf *ppl_conf = log->ppl_conf;
struct stripe_head *sh, *next;
pr_debug("%s: seq: %llu\n", __func__, io->seq);
if (bio->bi_status)
md_error(ppl_conf->mddev, log->rdev);
list_for_each_entry_safe(sh, next, &io->stripe_list, log_list) {
list_del_init(&sh->log_list);
set_bit(STRIPE_HANDLE, &sh->state);
raid5_release_stripe(sh);
}
}
static void ppl_submit_iounit_bio(struct ppl_io_unit *io, struct bio *bio)
{
char b[BDEVNAME_SIZE];
pr_debug("%s: seq: %llu size: %u sector: %llu dev: %s\n",
__func__, io->seq, bio->bi_iter.bi_size,
(unsigned long long)bio->bi_iter.bi_sector,
bio_devname(bio, b));
submit_bio(bio);
}
static void ppl_submit_iounit(struct ppl_io_unit *io)
{
struct ppl_log *log = io->log;
struct ppl_conf *ppl_conf = log->ppl_conf;
struct ppl_header *pplhdr = page_address(io->header_page);
struct bio *bio = &io->bio;
struct stripe_head *sh;
int i;
bio->bi_private = io;
if (!log->rdev || test_bit(Faulty, &log->rdev->flags)) {
ppl_log_endio(bio);
return;
}
for (i = 0; i < io->entries_count; i++) {
struct ppl_header_entry *e = &pplhdr->entries[i];
pr_debug("%s: seq: %llu entry: %d data_sector: %llu pp_size: %u data_size: %u\n",
__func__, io->seq, i, le64_to_cpu(e->data_sector),
le32_to_cpu(e->pp_size), le32_to_cpu(e->data_size));
e->data_sector = cpu_to_le64(le64_to_cpu(e->data_sector) >>
ilog2(ppl_conf->block_size >> 9));
e->checksum = cpu_to_le32(~le32_to_cpu(e->checksum));
}
pplhdr->entries_count = cpu_to_le32(io->entries_count);
pplhdr->checksum = cpu_to_le32(~crc32c_le(~0, pplhdr, PPL_HEADER_SIZE));
/* Rewind the buffer if current PPL is larger then remaining space */
if (log->use_multippl &&
log->rdev->ppl.sector + log->rdev->ppl.size - log->next_io_sector <
(PPL_HEADER_SIZE + io->pp_size) >> 9)
log->next_io_sector = log->rdev->ppl.sector;
bio->bi_end_io = ppl_log_endio;
bio->bi_opf = REQ_OP_WRITE | REQ_FUA;
bio_set_dev(bio, log->rdev->bdev);
bio->bi_iter.bi_sector = log->next_io_sector;
bio_add_page(bio, io->header_page, PAGE_SIZE, 0);
bio->bi_write_hint = ppl_conf->write_hint;
pr_debug("%s: log->current_io_sector: %llu\n", __func__,
(unsigned long long)log->next_io_sector);
if (log->use_multippl)
log->next_io_sector += (PPL_HEADER_SIZE + io->pp_size) >> 9;
WARN_ON(log->disk_flush_bitmap != 0);
list_for_each_entry(sh, &io->stripe_list, log_list) {
for (i = 0; i < sh->disks; i++) {
struct r5dev *dev = &sh->dev[i];
if ((ppl_conf->child_logs[i].wb_cache_on) &&
(test_bit(R5_Wantwrite, &dev->flags))) {
set_bit(i, &log->disk_flush_bitmap);
}
}
/* entries for full stripe writes have no partial parity */
if (test_bit(STRIPE_FULL_WRITE, &sh->state))
continue;
if (!bio_add_page(bio, sh->ppl_page, PAGE_SIZE, 0)) {
struct bio *prev = bio;
bio = bio_alloc_bioset(GFP_NOIO, BIO_MAX_VECS,
&ppl_conf->bs);
bio->bi_opf = prev->bi_opf;
bio->bi_write_hint = prev->bi_write_hint;
bio_copy_dev(bio, prev);
bio->bi_iter.bi_sector = bio_end_sector(prev);
bio_add_page(bio, sh->ppl_page, PAGE_SIZE, 0);
bio_chain(bio, prev);
ppl_submit_iounit_bio(io, prev);
}
}
ppl_submit_iounit_bio(io, bio);
}
static void ppl_submit_current_io(struct ppl_log *log)
{
struct ppl_io_unit *io;
spin_lock_irq(&log->io_list_lock);
io = list_first_entry_or_null(&log->io_list, struct ppl_io_unit,
log_sibling);
if (io && io->submitted)
io = NULL;
spin_unlock_irq(&log->io_list_lock);
if (io) {
io->submitted = true;
if (io == log->current_io)
log->current_io = NULL;
ppl_submit_iounit(io);
}
}
void ppl_write_stripe_run(struct r5conf *conf)
{
struct ppl_conf *ppl_conf = conf->log_private;
struct ppl_log *log;
int i;
for (i = 0; i < ppl_conf->count; i++) {
log = &ppl_conf->child_logs[i];
mutex_lock(&log->io_mutex);
ppl_submit_current_io(log);
mutex_unlock(&log->io_mutex);
}
}
static void ppl_io_unit_finished(struct ppl_io_unit *io)
{
struct ppl_log *log = io->log;
struct ppl_conf *ppl_conf = log->ppl_conf;
struct r5conf *conf = ppl_conf->mddev->private;
unsigned long flags;
pr_debug("%s: seq: %llu\n", __func__, io->seq);
local_irq_save(flags);
spin_lock(&log->io_list_lock);
list_del(&io->log_sibling);
spin_unlock(&log->io_list_lock);
mempool_free(io, &ppl_conf->io_pool);
spin_lock(&ppl_conf->no_mem_stripes_lock);
if (!list_empty(&ppl_conf->no_mem_stripes)) {
struct stripe_head *sh;
sh = list_first_entry(&ppl_conf->no_mem_stripes,
struct stripe_head, log_list);
list_del_init(&sh->log_list);
set_bit(STRIPE_HANDLE, &sh->state);
raid5_release_stripe(sh);
}
spin_unlock(&ppl_conf->no_mem_stripes_lock);
local_irq_restore(flags);
wake_up(&conf->wait_for_quiescent);
}
static void ppl_flush_endio(struct bio *bio)
{
struct ppl_io_unit *io = bio->bi_private;
struct ppl_log *log = io->log;
struct ppl_conf *ppl_conf = log->ppl_conf;
struct r5conf *conf = ppl_conf->mddev->private;
char b[BDEVNAME_SIZE];
pr_debug("%s: dev: %s\n", __func__, bio_devname(bio, b));
if (bio->bi_status) {
struct md_rdev *rdev;
rcu_read_lock();
rdev = md_find_rdev_rcu(conf->mddev, bio_dev(bio));
if (rdev)
md_error(rdev->mddev, rdev);
rcu_read_unlock();
}
bio_put(bio);
if (atomic_dec_and_test(&io->pending_flushes)) {
ppl_io_unit_finished(io);
md_wakeup_thread(conf->mddev->thread);
}
}
static void ppl_do_flush(struct ppl_io_unit *io)
{
struct ppl_log *log = io->log;
struct ppl_conf *ppl_conf = log->ppl_conf;
struct r5conf *conf = ppl_conf->mddev->private;
int raid_disks = conf->raid_disks;
int flushed_disks = 0;
int i;
atomic_set(&io->pending_flushes, raid_disks);
for_each_set_bit(i, &log->disk_flush_bitmap, raid_disks) {
struct md_rdev *rdev;
struct block_device *bdev = NULL;
rcu_read_lock();
rdev = rcu_dereference(conf->disks[i].rdev);
if (rdev && !test_bit(Faulty, &rdev->flags))
bdev = rdev->bdev;
rcu_read_unlock();
if (bdev) {
struct bio *bio;
char b[BDEVNAME_SIZE];
bio = bio_alloc_bioset(GFP_NOIO, 0, &ppl_conf->flush_bs);
bio_set_dev(bio, bdev);
bio->bi_private = io;
bio->bi_opf = REQ_OP_WRITE | REQ_PREFLUSH;
bio->bi_end_io = ppl_flush_endio;
pr_debug("%s: dev: %s\n", __func__,
bio_devname(bio, b));
submit_bio(bio);
flushed_disks++;
}
}
log->disk_flush_bitmap = 0;
for (i = flushed_disks ; i < raid_disks; i++) {
if (atomic_dec_and_test(&io->pending_flushes))
ppl_io_unit_finished(io);
}
}
static inline bool ppl_no_io_unit_submitted(struct r5conf *conf,
struct ppl_log *log)
{
struct ppl_io_unit *io;
io = list_first_entry_or_null(&log->io_list, struct ppl_io_unit,
log_sibling);
return !io || !io->submitted;
}
void ppl_quiesce(struct r5conf *conf, int quiesce)
{
struct ppl_conf *ppl_conf = conf->log_private;
int i;
if (quiesce) {
for (i = 0; i < ppl_conf->count; i++) {
struct ppl_log *log = &ppl_conf->child_logs[i];
spin_lock_irq(&log->io_list_lock);
wait_event_lock_irq(conf->wait_for_quiescent,
ppl_no_io_unit_submitted(conf, log),
log->io_list_lock);
spin_unlock_irq(&log->io_list_lock);
}
}
}
int ppl_handle_flush_request(struct r5l_log *log, struct bio *bio)
{
if (bio->bi_iter.bi_size == 0) {
bio_endio(bio);
return 0;
}
bio->bi_opf &= ~REQ_PREFLUSH;
return -EAGAIN;
}
void ppl_stripe_write_finished(struct stripe_head *sh)
{
struct ppl_io_unit *io;
io = sh->ppl_io;
sh->ppl_io = NULL;
if (io && atomic_dec_and_test(&io->pending_stripes)) {
if (io->log->disk_flush_bitmap)
ppl_do_flush(io);
else
ppl_io_unit_finished(io);
}
}
static void ppl_xor(int size, struct page *page1, struct page *page2)
{
struct async_submit_ctl submit;
struct dma_async_tx_descriptor *tx;
struct page *xor_srcs[] = { page1, page2 };
init_async_submit(&submit, ASYNC_TX_ACK|ASYNC_TX_XOR_DROP_DST,
NULL, NULL, NULL, NULL);
tx = async_xor(page1, xor_srcs, 0, 2, size, &submit);
async_tx_quiesce(&tx);
}
/*
* PPL recovery strategy: xor partial parity and data from all modified data
* disks within a stripe and write the result as the new stripe parity. If all
* stripe data disks are modified (full stripe write), no partial parity is
* available, so just xor the data disks.
*
* Recovery of a PPL entry shall occur only if all modified data disks are
* available and read from all of them succeeds.
*
* A PPL entry applies to a stripe, partial parity size for an entry is at most
* the size of the chunk. Examples of possible cases for a single entry:
*
* case 0: single data disk write:
* data0 data1 data2 ppl parity
* +--------+--------+--------+ +--------------------+
* | ------ | ------ | ------ | +----+ | (no change) |
* | ------ | -data- | ------ | | pp | -> | data1 ^ pp |
* | ------ | -data- | ------ | | pp | -> | data1 ^ pp |
* | ------ | ------ | ------ | +----+ | (no change) |
* +--------+--------+--------+ +--------------------+
* pp_size = data_size
*
* case 1: more than one data disk write:
* data0 data1 data2 ppl parity
* +--------+--------+--------+ +--------------------+
* | ------ | ------ | ------ | +----+ | (no change) |
* | -data- | -data- | ------ | | pp | -> | data0 ^ data1 ^ pp |
* | -data- | -data- | ------ | | pp | -> | data0 ^ data1 ^ pp |
* | ------ | ------ | ------ | +----+ | (no change) |
* +--------+--------+--------+ +--------------------+
* pp_size = data_size / modified_data_disks
*
* case 2: write to all data disks (also full stripe write):
* data0 data1 data2 parity
* +--------+--------+--------+ +--------------------+
* | ------ | ------ | ------ | | (no change) |
* | -data- | -data- | -data- | --------> | xor all data |
* | ------ | ------ | ------ | --------> | (no change) |
* | ------ | ------ | ------ | | (no change) |
* +--------+--------+--------+ +--------------------+
* pp_size = 0
*
* The following cases are possible only in other implementations. The recovery
* code can handle them, but they are not generated at runtime because they can
* be reduced to cases 0, 1 and 2:
*
* case 3:
* data0 data1 data2 ppl parity
* +--------+--------+--------+ +----+ +--------------------+
* | ------ | -data- | -data- | | pp | | data1 ^ data2 ^ pp |
* | ------ | -data- | -data- | | pp | -> | data1 ^ data2 ^ pp |
* | -data- | -data- | -data- | | -- | -> | xor all data |
* | -data- | -data- | ------ | | pp | | data0 ^ data1 ^ pp |
* +--------+--------+--------+ +----+ +--------------------+
* pp_size = chunk_size
*
* case 4:
* data0 data1 data2 ppl parity
* +--------+--------+--------+ +----+ +--------------------+
* | ------ | -data- | ------ | | pp | | data1 ^ pp |
* | ------ | ------ | ------ | | -- | -> | (no change) |
* | ------ | ------ | ------ | | -- | -> | (no change) |
* | -data- | ------ | ------ | | pp | | data0 ^ pp |
* +--------+--------+--------+ +----+ +--------------------+
* pp_size = chunk_size
*/
static int ppl_recover_entry(struct ppl_log *log, struct ppl_header_entry *e,
sector_t ppl_sector)
{
struct ppl_conf *ppl_conf = log->ppl_conf;
struct mddev *mddev = ppl_conf->mddev;
struct r5conf *conf = mddev->private;
int block_size = ppl_conf->block_size;
struct page *page1;
struct page *page2;
sector_t r_sector_first;
sector_t r_sector_last;
int strip_sectors;
int data_disks;
int i;
int ret = 0;
char b[BDEVNAME_SIZE];
unsigned int pp_size = le32_to_cpu(e->pp_size);
unsigned int data_size = le32_to_cpu(e->data_size);
page1 = alloc_page(GFP_KERNEL);
page2 = alloc_page(GFP_KERNEL);
if (!page1 || !page2) {
ret = -ENOMEM;
goto out;
}
r_sector_first = le64_to_cpu(e->data_sector) * (block_size >> 9);
if ((pp_size >> 9) < conf->chunk_sectors) {
if (pp_size > 0) {
data_disks = data_size / pp_size;
strip_sectors = pp_size >> 9;
} else {
data_disks = conf->raid_disks - conf->max_degraded;
strip_sectors = (data_size >> 9) / data_disks;
}
r_sector_last = r_sector_first +
(data_disks - 1) * conf->chunk_sectors +
strip_sectors;
} else {
data_disks = conf->raid_disks - conf->max_degraded;
strip_sectors = conf->chunk_sectors;
r_sector_last = r_sector_first + (data_size >> 9);
}
pr_debug("%s: array sector first: %llu last: %llu\n", __func__,
(unsigned long long)r_sector_first,
(unsigned long long)r_sector_last);
/* if start and end is 4k aligned, use a 4k block */
if (block_size == 512 &&
(r_sector_first & (RAID5_STRIPE_SECTORS(conf) - 1)) == 0 &&
(r_sector_last & (RAID5_STRIPE_SECTORS(conf) - 1)) == 0)
block_size = RAID5_STRIPE_SIZE(conf);
/* iterate through blocks in strip */
for (i = 0; i < strip_sectors; i += (block_size >> 9)) {
bool update_parity = false;
sector_t parity_sector;
struct md_rdev *parity_rdev;
struct stripe_head sh;
int disk;
int indent = 0;
pr_debug("%s:%*s iter %d start\n", __func__, indent, "", i);
indent += 2;
memset(page_address(page1), 0, PAGE_SIZE);
/* iterate through data member disks */
for (disk = 0; disk < data_disks; disk++) {
int dd_idx;
struct md_rdev *rdev;
sector_t sector;
sector_t r_sector = r_sector_first + i +
(disk * conf->chunk_sectors);
pr_debug("%s:%*s data member disk %d start\n",
__func__, indent, "", disk);
indent += 2;
if (r_sector >= r_sector_last) {
pr_debug("%s:%*s array sector %llu doesn't need parity update\n",
__func__, indent, "",
(unsigned long long)r_sector);
indent -= 2;
continue;
}
update_parity = true;
/* map raid sector to member disk */
sector = raid5_compute_sector(conf, r_sector, 0,
&dd_idx, NULL);
pr_debug("%s:%*s processing array sector %llu => data member disk %d, sector %llu\n",
__func__, indent, "",
(unsigned long long)r_sector, dd_idx,
(unsigned long long)sector);
rdev = conf->disks[dd_idx].rdev;
if (!rdev || (!test_bit(In_sync, &rdev->flags) &&
sector >= rdev->recovery_offset)) {
pr_debug("%s:%*s data member disk %d missing\n",
__func__, indent, "", dd_idx);
update_parity = false;
break;
}
pr_debug("%s:%*s reading data member disk %s sector %llu\n",
__func__, indent, "", bdevname(rdev->bdev, b),
(unsigned long long)sector);
if (!sync_page_io(rdev, sector, block_size, page2,
REQ_OP_READ, 0, false)) {
md_error(mddev, rdev);
pr_debug("%s:%*s read failed!\n", __func__,
indent, "");
ret = -EIO;
goto out;
}
ppl_xor(block_size, page1, page2);
indent -= 2;
}
if (!update_parity)
continue;
if (pp_size > 0) {
pr_debug("%s:%*s reading pp disk sector %llu\n",
__func__, indent, "",
(unsigned long long)(ppl_sector + i));
if (!sync_page_io(log->rdev,
ppl_sector - log->rdev->data_offset + i,
block_size, page2, REQ_OP_READ, 0,
false)) {
pr_debug("%s:%*s read failed!\n", __func__,
indent, "");
md_error(mddev, log->rdev);
ret = -EIO;
goto out;
}
ppl_xor(block_size, page1, page2);
}
/* map raid sector to parity disk */
parity_sector = raid5_compute_sector(conf, r_sector_first + i,
0, &disk, &sh);
BUG_ON(sh.pd_idx != le32_to_cpu(e->parity_disk));
parity_rdev = conf->disks[sh.pd_idx].rdev;
BUG_ON(parity_rdev->bdev->bd_dev != log->rdev->bdev->bd_dev);
pr_debug("%s:%*s write parity at sector %llu, disk %s\n",
__func__, indent, "",
(unsigned long long)parity_sector,
bdevname(parity_rdev->bdev, b));
if (!sync_page_io(parity_rdev, parity_sector, block_size,
page1, REQ_OP_WRITE, 0, false)) {
pr_debug("%s:%*s parity write error!\n", __func__,
indent, "");
md_error(mddev, parity_rdev);
ret = -EIO;
goto out;
}
}
out:
if (page1)
__free_page(page1);
if (page2)
__free_page(page2);
return ret;
}
static int ppl_recover(struct ppl_log *log, struct ppl_header *pplhdr,
sector_t offset)
{
struct ppl_conf *ppl_conf = log->ppl_conf;
struct md_rdev *rdev = log->rdev;
struct mddev *mddev = rdev->mddev;
sector_t ppl_sector = rdev->ppl.sector + offset +
(PPL_HEADER_SIZE >> 9);
struct page *page;
int i;
int ret = 0;
page = alloc_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
/* iterate through all PPL entries saved */
for (i = 0; i < le32_to_cpu(pplhdr->entries_count); i++) {
struct ppl_header_entry *e = &pplhdr->entries[i];
u32 pp_size = le32_to_cpu(e->pp_size);
sector_t sector = ppl_sector;
int ppl_entry_sectors = pp_size >> 9;
u32 crc, crc_stored;
pr_debug("%s: disk: %d entry: %d ppl_sector: %llu pp_size: %u\n",
__func__, rdev->raid_disk, i,
(unsigned long long)ppl_sector, pp_size);
crc = ~0;
crc_stored = le32_to_cpu(e->checksum);
/* read parial parity for this entry and calculate its checksum */
while (pp_size) {
int s = pp_size > PAGE_SIZE ? PAGE_SIZE : pp_size;
if (!sync_page_io(rdev, sector - rdev->data_offset,
s, page, REQ_OP_READ, 0, false)) {
md_error(mddev, rdev);
ret = -EIO;
goto out;
}
crc = crc32c_le(crc, page_address(page), s);
pp_size -= s;
sector += s >> 9;
}
crc = ~crc;
if (crc != crc_stored) {
/*
* Don't recover this entry if the checksum does not
* match, but keep going and try to recover other
* entries.
*/
pr_debug("%s: ppl entry crc does not match: stored: 0x%x calculated: 0x%x\n",
__func__, crc_stored, crc);
ppl_conf->mismatch_count++;
} else {
ret = ppl_recover_entry(log, e, ppl_sector);
if (ret)
goto out;
ppl_conf->recovered_entries++;
}
ppl_sector += ppl_entry_sectors;
}
/* flush the disk cache after recovery if necessary */
ret = blkdev_issue_flush(rdev->bdev);
out:
__free_page(page);
return ret;
}
static int ppl_write_empty_header(struct ppl_log *log)
{
struct page *page;
struct ppl_header *pplhdr;
struct md_rdev *rdev = log->rdev;
int ret = 0;
pr_debug("%s: disk: %d ppl_sector: %llu\n", __func__,
rdev->raid_disk, (unsigned long long)rdev->ppl.sector);
page = alloc_page(GFP_NOIO | __GFP_ZERO);
if (!page)
return -ENOMEM;
pplhdr = page_address(page);
/* zero out PPL space to avoid collision with old PPLs */
blkdev_issue_zeroout(rdev->bdev, rdev->ppl.sector,
log->rdev->ppl.size, GFP_NOIO, 0);
memset(pplhdr->reserved, 0xff, PPL_HDR_RESERVED);
pplhdr->signature = cpu_to_le32(log->ppl_conf->signature);
pplhdr->checksum = cpu_to_le32(~crc32c_le(~0, pplhdr, PAGE_SIZE));
if (!sync_page_io(rdev, rdev->ppl.sector - rdev->data_offset,
PPL_HEADER_SIZE, page, REQ_OP_WRITE | REQ_SYNC |
REQ_FUA, 0, false)) {
md_error(rdev->mddev, rdev);
ret = -EIO;
}
__free_page(page);
return ret;
}
static int ppl_load_distributed(struct ppl_log *log)
{
struct ppl_conf *ppl_conf = log->ppl_conf;
struct md_rdev *rdev = log->rdev;
struct mddev *mddev = rdev->mddev;
struct page *page, *page2, *tmp;
struct ppl_header *pplhdr = NULL, *prev_pplhdr = NULL;
u32 crc, crc_stored;
u32 signature;
int ret = 0, i;
sector_t pplhdr_offset = 0, prev_pplhdr_offset = 0;
pr_debug("%s: disk: %d\n", __func__, rdev->raid_disk);
/* read PPL headers, find the recent one */
page = alloc_page(GFP_KERNEL);
if (!page)
return -ENOMEM;
page2 = alloc_page(GFP_KERNEL);
if (!page2) {
__free_page(page);
return -ENOMEM;
}
/* searching ppl area for latest ppl */
while (pplhdr_offset < rdev->ppl.size - (PPL_HEADER_SIZE >> 9)) {
if (!sync_page_io(rdev,
rdev->ppl.sector - rdev->data_offset +
pplhdr_offset, PAGE_SIZE, page, REQ_OP_READ,
0, false)) {
md_error(mddev, rdev);
ret = -EIO;
/* if not able to read - don't recover any PPL */
pplhdr = NULL;
break;
}
pplhdr = page_address(page);
/* check header validity */
crc_stored = le32_to_cpu(pplhdr->checksum);
pplhdr->checksum = 0;
crc = ~crc32c_le(~0, pplhdr, PAGE_SIZE);
if (crc_stored != crc) {
pr_debug("%s: ppl header crc does not match: stored: 0x%x calculated: 0x%x (offset: %llu)\n",
__func__, crc_stored, crc,
(unsigned long long)pplhdr_offset);
pplhdr = prev_pplhdr;
pplhdr_offset = prev_pplhdr_offset;
break;
}
signature = le32_to_cpu(pplhdr->signature);
if (mddev->external) {
/*
* For external metadata the header signature is set and
* validated in userspace.
*/
ppl_conf->signature = signature;
} else if (ppl_conf->signature != signature) {
pr_debug("%s: ppl header signature does not match: stored: 0x%x configured: 0x%x (offset: %llu)\n",
__func__, signature, ppl_conf->signature,
(unsigned long long)pplhdr_offset);
pplhdr = prev_pplhdr;
pplhdr_offset = prev_pplhdr_offset;
break;
}
if (prev_pplhdr && le64_to_cpu(prev_pplhdr->generation) >
le64_to_cpu(pplhdr->generation)) {
/* previous was newest */
pplhdr = prev_pplhdr;
pplhdr_offset = prev_pplhdr_offset;
break;
}
prev_pplhdr_offset = pplhdr_offset;
prev_pplhdr = pplhdr;
tmp = page;
page = page2;
page2 = tmp;
/* calculate next potential ppl offset */
for (i = 0; i < le32_to_cpu(pplhdr->entries_count); i++)
pplhdr_offset +=
le32_to_cpu(pplhdr->entries[i].pp_size) >> 9;
pplhdr_offset += PPL_HEADER_SIZE >> 9;
}
/* no valid ppl found */
if (!pplhdr)
ppl_conf->mismatch_count++;
else
pr_debug("%s: latest PPL found at offset: %llu, with generation: %llu\n",
__func__, (unsigned long long)pplhdr_offset,
le64_to_cpu(pplhdr->generation));
/* attempt to recover from log if we are starting a dirty array */
if (pplhdr && !mddev->pers && mddev->recovery_cp != MaxSector)
ret = ppl_recover(log, pplhdr, pplhdr_offset);
/* write empty header if we are starting the array */
if (!ret && !mddev->pers)
ret = ppl_write_empty_header(log);
__free_page(page);
__free_page(page2);
pr_debug("%s: return: %d mismatch_count: %d recovered_entries: %d\n",
__func__, ret, ppl_conf->mismatch_count,
ppl_conf->recovered_entries);
return ret;
}
static int ppl_load(struct ppl_conf *ppl_conf)
{
int ret = 0;
u32 signature = 0;
bool signature_set = false;
int i;
for (i = 0; i < ppl_conf->count; i++) {
struct ppl_log *log = &ppl_conf->child_logs[i];
/* skip missing drive */
if (!log->rdev)
continue;
ret = ppl_load_distributed(log);
if (ret)
break;
/*
* For external metadata we can't check if the signature is
* correct on a single drive, but we can check if it is the same
* on all drives.
*/
if (ppl_conf->mddev->external) {
if (!signature_set) {
signature = ppl_conf->signature;
signature_set = true;
} else if (signature != ppl_conf->signature) {
pr_warn("md/raid:%s: PPL header signature does not match on all member drives\n",
mdname(ppl_conf->mddev));
ret = -EINVAL;
break;
}
}
}
pr_debug("%s: return: %d mismatch_count: %d recovered_entries: %d\n",
__func__, ret, ppl_conf->mismatch_count,
ppl_conf->recovered_entries);
return ret;
}
static void __ppl_exit_log(struct ppl_conf *ppl_conf)
{
clear_bit(MD_HAS_PPL, &ppl_conf->mddev->flags);
clear_bit(MD_HAS_MULTIPLE_PPLS, &ppl_conf->mddev->flags);
kfree(ppl_conf->child_logs);
bioset_exit(&ppl_conf->bs);
bioset_exit(&ppl_conf->flush_bs);
mempool_exit(&ppl_conf->io_pool);
kmem_cache_destroy(ppl_conf->io_kc);
kfree(ppl_conf);
}
void ppl_exit_log(struct r5conf *conf)
{
struct ppl_conf *ppl_conf = conf->log_private;
if (ppl_conf) {
__ppl_exit_log(ppl_conf);
conf->log_private = NULL;
}
}
static int ppl_validate_rdev(struct md_rdev *rdev)
{
char b[BDEVNAME_SIZE];
int ppl_data_sectors;
int ppl_size_new;
/*
* The configured PPL size must be enough to store
* the header and (at the very least) partial parity
* for one stripe. Round it down to ensure the data
* space is cleanly divisible by stripe size.
*/
ppl_data_sectors = rdev->ppl.size - (PPL_HEADER_SIZE >> 9);
if (ppl_data_sectors > 0)
ppl_data_sectors = rounddown(ppl_data_sectors,
RAID5_STRIPE_SECTORS((struct r5conf *)rdev->mddev->private));
if (ppl_data_sectors <= 0) {
pr_warn("md/raid:%s: PPL space too small on %s\n",
mdname(rdev->mddev), bdevname(rdev->bdev, b));
return -ENOSPC;
}
ppl_size_new = ppl_data_sectors + (PPL_HEADER_SIZE >> 9);
if ((rdev->ppl.sector < rdev->data_offset &&
rdev->ppl.sector + ppl_size_new > rdev->data_offset) ||
(rdev->ppl.sector >= rdev->data_offset &&
rdev->data_offset + rdev->sectors > rdev->ppl.sector)) {
pr_warn("md/raid:%s: PPL space overlaps with data on %s\n",
mdname(rdev->mddev), bdevname(rdev->bdev, b));
return -EINVAL;
}
if (!rdev->mddev->external &&
((rdev->ppl.offset > 0 && rdev->ppl.offset < (rdev->sb_size >> 9)) ||
(rdev->ppl.offset <= 0 && rdev->ppl.offset + ppl_size_new > 0))) {
pr_warn("md/raid:%s: PPL space overlaps with superblock on %s\n",
mdname(rdev->mddev), bdevname(rdev->bdev, b));
return -EINVAL;
}
rdev->ppl.size = ppl_size_new;
return 0;
}
static void ppl_init_child_log(struct ppl_log *log, struct md_rdev *rdev)
{
struct request_queue *q;
if ((rdev->ppl.size << 9) >= (PPL_SPACE_SIZE +
PPL_HEADER_SIZE) * 2) {
log->use_multippl = true;
set_bit(MD_HAS_MULTIPLE_PPLS,
&log->ppl_conf->mddev->flags);
log->entry_space = PPL_SPACE_SIZE;
} else {
log->use_multippl = false;
log->entry_space = (log->rdev->ppl.size << 9) -
PPL_HEADER_SIZE;
}
log->next_io_sector = rdev->ppl.sector;
q = bdev_get_queue(rdev->bdev);
if (test_bit(QUEUE_FLAG_WC, &q->queue_flags))
log->wb_cache_on = true;
}
int ppl_init_log(struct r5conf *conf)
{
struct ppl_conf *ppl_conf;
struct mddev *mddev = conf->mddev;
int ret = 0;
int max_disks;
int i;
pr_debug("md/raid:%s: enabling distributed Partial Parity Log\n",
mdname(conf->mddev));
if (PAGE_SIZE != 4096)
return -EINVAL;
if (mddev->level != 5) {
pr_warn("md/raid:%s PPL is not compatible with raid level %d\n",
mdname(mddev), mddev->level);
return -EINVAL;
}
if (mddev->bitmap_info.file || mddev->bitmap_info.offset) {
pr_warn("md/raid:%s PPL is not compatible with bitmap\n",
mdname(mddev));
return -EINVAL;
}
if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
pr_warn("md/raid:%s PPL is not compatible with journal\n",
mdname(mddev));
return -EINVAL;
}
max_disks = sizeof_field(struct ppl_log, disk_flush_bitmap) *
BITS_PER_BYTE;
if (conf->raid_disks > max_disks) {
pr_warn("md/raid:%s PPL doesn't support over %d disks in the array\n",
mdname(mddev), max_disks);
return -EINVAL;
}
ppl_conf = kzalloc(sizeof(struct ppl_conf), GFP_KERNEL);
if (!ppl_conf)
return -ENOMEM;
ppl_conf->mddev = mddev;
ppl_conf->io_kc = KMEM_CACHE(ppl_io_unit, 0);
if (!ppl_conf->io_kc) {
ret = -ENOMEM;
goto err;
}
ret = mempool_init(&ppl_conf->io_pool, conf->raid_disks, ppl_io_pool_alloc,
ppl_io_pool_free, ppl_conf->io_kc);
if (ret)
goto err;
ret = bioset_init(&ppl_conf->bs, conf->raid_disks, 0, BIOSET_NEED_BVECS);
if (ret)
goto err;
ret = bioset_init(&ppl_conf->flush_bs, conf->raid_disks, 0, 0);
if (ret)
goto err;
ppl_conf->count = conf->raid_disks;
ppl_conf->child_logs = kcalloc(ppl_conf->count, sizeof(struct ppl_log),
GFP_KERNEL);
if (!ppl_conf->child_logs) {
ret = -ENOMEM;
goto err;
}
atomic64_set(&ppl_conf->seq, 0);
INIT_LIST_HEAD(&ppl_conf->no_mem_stripes);
spin_lock_init(&ppl_conf->no_mem_stripes_lock);
ppl_conf->write_hint = RWH_WRITE_LIFE_NOT_SET;
if (!mddev->external) {
ppl_conf->signature = ~crc32c_le(~0, mddev->uuid, sizeof(mddev->uuid));
ppl_conf->block_size = 512;
} else {
ppl_conf->block_size = queue_logical_block_size(mddev->queue);
}
for (i = 0; i < ppl_conf->count; i++) {
struct ppl_log *log = &ppl_conf->child_logs[i];
struct md_rdev *rdev = conf->disks[i].rdev;
mutex_init(&log->io_mutex);
spin_lock_init(&log->io_list_lock);
INIT_LIST_HEAD(&log->io_list);
log->ppl_conf = ppl_conf;
log->rdev = rdev;
if (rdev) {
ret = ppl_validate_rdev(rdev);
if (ret)
goto err;
ppl_init_child_log(log, rdev);
}
}
/* load and possibly recover the logs from the member disks */
ret = ppl_load(ppl_conf);
if (ret) {
goto err;
} else if (!mddev->pers && mddev->recovery_cp == 0 &&
ppl_conf->recovered_entries > 0 &&
ppl_conf->mismatch_count == 0) {
/*
* If we are starting a dirty array and the recovery succeeds
* without any issues, set the array as clean.
*/
mddev->recovery_cp = MaxSector;
set_bit(MD_SB_CHANGE_CLEAN, &mddev->sb_flags);
} else if (mddev->pers && ppl_conf->mismatch_count > 0) {
/* no mismatch allowed when enabling PPL for a running array */
ret = -EINVAL;
goto err;
}
conf->log_private = ppl_conf;
set_bit(MD_HAS_PPL, &ppl_conf->mddev->flags);
return 0;
err:
__ppl_exit_log(ppl_conf);
return ret;
}
int ppl_modify_log(struct r5conf *conf, struct md_rdev *rdev, bool add)
{
struct ppl_conf *ppl_conf = conf->log_private;
struct ppl_log *log;
int ret = 0;
char b[BDEVNAME_SIZE];
if (!rdev)
return -EINVAL;
pr_debug("%s: disk: %d operation: %s dev: %s\n",
__func__, rdev->raid_disk, add ? "add" : "remove",
bdevname(rdev->bdev, b));
if (rdev->raid_disk < 0)
return 0;
if (rdev->raid_disk >= ppl_conf->count)
return -ENODEV;
log = &ppl_conf->child_logs[rdev->raid_disk];
mutex_lock(&log->io_mutex);
if (add) {
ret = ppl_validate_rdev(rdev);
if (!ret) {
log->rdev = rdev;
ret = ppl_write_empty_header(log);
ppl_init_child_log(log, rdev);
}
} else {
log->rdev = NULL;
}
mutex_unlock(&log->io_mutex);
return ret;
}
static ssize_t
ppl_write_hint_show(struct mddev *mddev, char *buf)
{
size_t ret = 0;
struct r5conf *conf;
struct ppl_conf *ppl_conf = NULL;
spin_lock(&mddev->lock);
conf = mddev->private;
if (conf && raid5_has_ppl(conf))
ppl_conf = conf->log_private;
ret = sprintf(buf, "%d\n", ppl_conf ? ppl_conf->write_hint : 0);
spin_unlock(&mddev->lock);
return ret;
}
static ssize_t
ppl_write_hint_store(struct mddev *mddev, const char *page, size_t len)
{
struct r5conf *conf;
struct ppl_conf *ppl_conf;
int err = 0;
unsigned short new;
if (len >= PAGE_SIZE)
return -EINVAL;
if (kstrtou16(page, 10, &new))
return -EINVAL;
err = mddev_lock(mddev);
if (err)
return err;
conf = mddev->private;
if (!conf) {
err = -ENODEV;
} else if (raid5_has_ppl(conf)) {
ppl_conf = conf->log_private;
if (!ppl_conf)
err = -EINVAL;
else
ppl_conf->write_hint = new;
} else {
err = -EINVAL;
}
mddev_unlock(mddev);
return err ?: len;
}
struct md_sysfs_entry
ppl_write_hint = __ATTR(ppl_write_hint, S_IRUGO | S_IWUSR,
ppl_write_hint_show,
ppl_write_hint_store);
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