--- /dev/null
+/*
+ * 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);
+}
projects / cascardo / linux.git / commitdiff