diff options
| -rw-r--r-- | Documentation/md/raid5-ppl.txt | 44 | ||||
| -rw-r--r-- | drivers/md/Makefile | 2 | ||||
| -rw-r--r-- | drivers/md/raid5-log.h | 24 | ||||
| -rw-r--r-- | drivers/md/raid5-ppl.c | 703 | ||||
| -rw-r--r-- | drivers/md/raid5.c | 64 | ||||
| -rw-r--r-- | drivers/md/raid5.h | 10 | ||||
| -rw-r--r-- | include/uapi/linux/raid/md_p.h | 27 |
7 files changed, 869 insertions, 5 deletions
diff --git a/Documentation/md/raid5-ppl.txt b/Documentation/md/raid5-ppl.txt new file mode 100644 index 0000000..127072b --- /dev/null +++ b/Documentation/md/raid5-ppl.txt @@ -0,0 +1,44 @@ +Partial Parity Log + +Partial Parity Log (PPL) is a feature available for RAID5 arrays. The issue +addressed by PPL is that after a dirty shutdown, parity of a particular stripe +may become inconsistent with data on other member disks. If the array is also +in degraded state, there is no way to recalculate parity, because one of the +disks is missing. This can lead to silent data corruption when rebuilding the +array or using it is as degraded - data calculated from parity for array blocks +that have not been touched by a write request during the unclean shutdown can +be incorrect. Such condition is known as the RAID5 Write Hole. Because of +this, md by default does not allow starting a dirty degraded array. + +Partial parity for a write operation is the XOR of stripe data chunks not +modified by this write. It is just enough data needed for recovering from the +write hole. XORing partial parity with the modified chunks produces parity for +the stripe, consistent with its state before the write operation, regardless of +which chunk writes have completed. If one of the not modified data disks of +this stripe is missing, this updated parity can be used to recover its +contents. PPL recovery is also performed when starting an array after an +unclean shutdown and all disks are available, eliminating the need to resync +the array. Because of this, using write-intent bitmap and PPL together is not +supported. + +When handling a write request PPL writes partial parity before new data and +parity are dispatched to disks. PPL is a distributed log - it is stored on +array member drives in the metadata area, on the parity drive of a particular +stripe. It does not require a dedicated journaling drive. Write performance is +reduced by up to 30%-40% but it scales with the number of drives in the array +and the journaling drive does not become a bottleneck or a single point of +failure. + +Unlike raid5-cache, the other solution in md for closing the write hole, PPL is +not a true journal. It does not protect from losing in-flight data, only from +silent data corruption. If a dirty disk of a stripe is lost, no PPL recovery is +performed for this stripe (parity is not updated). So it is possible to have +arbitrary data in the written part of a stripe if that disk is lost. In such +case the behavior is the same as in plain raid5. + +PPL is available for md version-1 metadata and external (specifically IMSM) +metadata arrays. It can be enabled using mdadm option --consistency-policy=ppl. + +Currently, volatile write-back cache should be disabled on all member drives +when using PPL. Otherwise it cannot guarantee consistency in case of power +failure. diff --git a/drivers/md/Makefile b/drivers/md/Makefile index 3cbda1a..4d48714 100644 --- a/drivers/md/Makefile +++ b/drivers/md/Makefile @@ -18,7 +18,7 @@ dm-cache-cleaner-y += dm-cache-policy-cleaner.o dm-era-y += dm-era-target.o dm-verity-y += dm-verity-target.o md-mod-y += md.o bitmap.o -raid456-y += raid5.o raid5-cache.o +raid456-y += raid5.o raid5-cache.o raid5-ppl.o # Note: link order is important. All raid personalities # and must come before md.o, as they each initialise diff --git a/drivers/md/raid5-log.h b/drivers/md/raid5-log.h index 2da4bd3..a67fb58 100644 --- a/drivers/md/raid5-log.h +++ b/drivers/md/raid5-log.h @@ -31,6 +31,20 @@ extern struct md_sysfs_entry r5c_journal_mode; extern void r5c_update_on_rdev_error(struct mddev *mddev); extern bool r5c_big_stripe_cached(struct r5conf *conf, sector_t sect); +extern struct dma_async_tx_descriptor * +ops_run_partial_parity(struct stripe_head *sh, struct raid5_percpu *percpu, + struct dma_async_tx_descriptor *tx); +extern int ppl_init_log(struct r5conf *conf); +extern void ppl_exit_log(struct r5conf *conf); +extern int ppl_write_stripe(struct r5conf *conf, struct stripe_head *sh); +extern void ppl_write_stripe_run(struct r5conf *conf); +extern void ppl_stripe_write_finished(struct stripe_head *sh); + +static inline bool raid5_has_ppl(struct r5conf *conf) +{ + return test_bit(MD_HAS_PPL, &conf->mddev->flags); +} + static inline int log_stripe(struct stripe_head *sh, struct stripe_head_state *s) { struct r5conf *conf = sh->raid_conf; @@ -45,6 +59,8 @@ static inline int log_stripe(struct stripe_head *sh, struct stripe_head_state *s /* caching phase */ return r5c_cache_data(conf->log, sh); } + } else if (raid5_has_ppl(conf)) { + return ppl_write_stripe(conf, sh); } return -EAGAIN; @@ -56,24 +72,32 @@ static inline void log_stripe_write_finished(struct stripe_head *sh) if (conf->log) r5l_stripe_write_finished(sh); + else if (raid5_has_ppl(conf)) + ppl_stripe_write_finished(sh); } static inline void log_write_stripe_run(struct r5conf *conf) { if (conf->log) r5l_write_stripe_run(conf->log); + else if (raid5_has_ppl(conf)) + ppl_write_stripe_run(conf); } static inline void log_exit(struct r5conf *conf) { if (conf->log) r5l_exit_log(conf); + else if (raid5_has_ppl(conf)) + ppl_exit_log(conf); } static inline int log_init(struct r5conf *conf, struct md_rdev *journal_dev) { if (journal_dev) return r5l_init_log(conf, journal_dev); + else if (raid5_has_ppl(conf)) + return ppl_init_log(conf); return 0; } diff --git a/drivers/md/raid5-ppl.c b/drivers/md/raid5-ppl.c new file mode 100644 index 0000000..db5b72b --- /dev/null +++ b/drivers/md/raid5-ppl.c @@ -0,0 +1,703 @@ +/* + * Partial Parity Log for closing the RAID5 write hole + * Copyright (c) 2017, Intel Corporation. + * + * 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/blkdev.h> +#include <linux/slab.h> +#include <linux/crc32c.h> +#include <linux/flex_array.h> +#include <linux/async_tx.h> +#include <linux/raid/md_p.h> +#include "md.h" +#include "raid5.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. + */ + +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; + mempool_t *meta_pool; +}; + +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 */ + struct list_head no_mem_stripes;/* stripes to retry if failed to + * allocate io_unit */ +}; + +#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 */ + + 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 **xor_srcs = flex_array_get(percpu->scribble, 0); + 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 */ + for (i = disks; i--;) { + struct r5dev *dev = &sh->dev[i]; + if (test_bit(R5_Wantdrain, &dev->flags) || i == pd_idx) + xor_srcs[count++] = dev->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)) + xor_srcs[count++] = dev->page; + } + } else { + return tx; + } + + init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, tx, + NULL, sh, flex_array_get(percpu->scribble, 0) + + sizeof(struct page *) * (sh->disks + 2)); + + if (count == 1) + tx = async_memcpy(sh->ppl_page, xor_srcs[0], 0, 0, PAGE_SIZE, + &submit); + else + tx = async_xor(sh->ppl_page, xor_srcs, 0, count, PAGE_SIZE, + &submit); + + return tx; +} + +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; + + io = mempool_alloc(ppl_conf->io_pool, GFP_ATOMIC); + if (!io) + return NULL; + + memset(io, 0, sizeof(*io)); + io->log = log; + INIT_LIST_HEAD(&io->log_sibling); + INIT_LIST_HEAD(&io->stripe_list); + atomic_set(&io->pending_stripes, 0); + bio_init(&io->bio, io->biovec, PPL_IO_INLINE_BVECS); + + io->header_page = mempool_alloc(ppl_conf->meta_pool, GFP_NOIO); + 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; + unsigned int entry_space = (log->rdev->ppl.size << 9) - PPL_HEADER_SIZE; + 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 == 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 + STRIPE_SECTORS) && + (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) || + !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(&log->io_list_lock); + list_add_tail(&sh->log_list, &log->no_mem_stripes); + spin_unlock_irq(&log->io_list_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_error) + md_error(ppl_conf->mddev, log->rdev); + + mempool_free(io->header_page, ppl_conf->meta_pool); + + 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, + bdevname(bio->bi_bdev, 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; + + 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)); + + bio->bi_private = io; + bio->bi_end_io = ppl_log_endio; + bio->bi_opf = REQ_OP_WRITE | REQ_FUA; + bio->bi_bdev = log->rdev->bdev; + bio->bi_iter.bi_sector = log->rdev->ppl.sector; + bio_add_page(bio, io->header_page, PAGE_SIZE, 0); + + list_for_each_entry(sh, &io->stripe_list, log_list) { + /* 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_PAGES, + ppl_conf->bs); + bio->bi_opf = prev->bi_opf; + bio->bi_bdev = prev->bi_bdev; + 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; + unsigned long flags; + + pr_debug("%s: seq: %llu\n", __func__, io->seq); + + spin_lock_irqsave(&log->io_list_lock, flags); + + list_del(&io->log_sibling); + mempool_free(io, log->ppl_conf->io_pool); + + if (!list_empty(&log->no_mem_stripes)) { + struct stripe_head *sh = list_first_entry(&log->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_irqrestore(&log->io_list_lock, flags); +} + +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)) + ppl_io_unit_finished(io); +} + +static void __ppl_exit_log(struct ppl_conf *ppl_conf) +{ + clear_bit(MD_HAS_PPL, &ppl_conf->mddev->flags); + + kfree(ppl_conf->child_logs); + + mempool_destroy(ppl_conf->meta_pool); + if (ppl_conf->bs) + bioset_free(ppl_conf->bs); + mempool_destroy(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, STRIPE_SECTORS); + + 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; +} + +int ppl_init_log(struct r5conf *conf) +{ + struct ppl_conf *ppl_conf; + struct mddev *mddev = conf->mddev; + int ret = 0; + int i; + bool need_cache_flush; + + 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; + } + + 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 = -EINVAL; + goto err; + } + + ppl_conf->io_pool = mempool_create_slab_pool(conf->raid_disks, ppl_conf->io_kc); + if (!ppl_conf->io_pool) { + ret = -EINVAL; + goto err; + } + + ppl_conf->bs = bioset_create(conf->raid_disks, 0); + if (!ppl_conf->bs) { + ret = -EINVAL; + goto err; + } + + ppl_conf->meta_pool = mempool_create_page_pool(conf->raid_disks, 0); + if (!ppl_conf->meta_pool) { + ret = -EINVAL; + 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); + + 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); + INIT_LIST_HEAD(&log->no_mem_stripes); + + log->ppl_conf = ppl_conf; + log->rdev = rdev; + + if (rdev) { + struct request_queue *q; + + ret = ppl_validate_rdev(rdev); + if (ret) + goto err; + + q = bdev_get_queue(rdev->bdev); + if (test_bit(QUEUE_FLAG_WC, &q->queue_flags)) + need_cache_flush = true; + } + } + + if (need_cache_flush) + pr_warn("md/raid:%s: Volatile write-back cache should be disabled on all member drives when using PPL!\n", + mdname(mddev)); + + conf->log_private = ppl_conf; + + return 0; +err: + __ppl_exit_log(ppl_conf); + return ret; +} diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index f575f40..6b86e08 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -482,6 +482,11 @@ static void shrink_buffers(struct stripe_head *sh) sh->dev[i].page = NULL; put_page(p); } + + if (sh->ppl_page) { + put_page(sh->ppl_page); + sh->ppl_page = NULL; + } } static int grow_buffers(struct stripe_head *sh, gfp_t gfp) @@ -498,6 +503,13 @@ static int grow_buffers(struct stripe_head *sh, gfp_t gfp) sh->dev[i].page = page; sh->dev[i].orig_page = page; } + + if (raid5_has_ppl(sh->raid_conf)) { + sh->ppl_page = alloc_page(gfp); + if (!sh->ppl_page) + return 1; + } + return 0; } @@ -746,7 +758,7 @@ static bool stripe_can_batch(struct stripe_head *sh) { struct r5conf *conf = sh->raid_conf; - if (conf->log) + if (conf->log || raid5_has_ppl(conf)) return false; return test_bit(STRIPE_BATCH_READY, &sh->state) && !test_bit(STRIPE_BITMAP_PENDING, &sh->state) && @@ -2093,6 +2105,9 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request) async_tx_ack(tx); } + if (test_bit(STRIPE_OP_PARTIAL_PARITY, &ops_request)) + tx = ops_run_partial_parity(sh, percpu, tx); + if (test_bit(STRIPE_OP_PREXOR, &ops_request)) { if (level < 6) tx = ops_run_prexor5(sh, percpu, tx); @@ -3168,6 +3183,12 @@ schedule_reconstruction(struct stripe_head *sh, struct stripe_head_state *s, s->locked++; } + if (raid5_has_ppl(sh->raid_conf) && + test_bit(STRIPE_OP_BIODRAIN, &s->ops_request) && + !test_bit(STRIPE_FULL_WRITE, &sh->state) && + test_bit(R5_Insync, &sh->dev[pd_idx].flags)) + set_bit(STRIPE_OP_PARTIAL_PARITY, &s->ops_request); + pr_debug("%s: stripe %llu locked: %d ops_request: %lx\n", __func__, (unsigned long long)sh->sector, s->locked, s->ops_request); @@ -3215,6 +3236,36 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, if (*bip && (*bip)->bi_iter.bi_sector < bio_end_sector(bi)) goto overlap; + if (forwrite && raid5_has_ppl(conf)) { + /* + * With PPL only writes to consecutive data chunks within a + * stripe are allowed because for a single stripe_head we can + * only have one PPL entry at a time, which describes one data + * range. Not really an overlap, but wait_for_overlap can be + * used to handle this. + */ + sector_t sector; + sector_t first = 0; + sector_t last = 0; + int count = 0; + int i; + + for (i = 0; i < sh->disks; i++) { + if (i != sh->pd_idx && + (i == dd_idx || sh->dev[i].towrite)) { + sector = sh->dev[i].sector; + if (count == 0 || sector < first) + first = sector; + if (sector > last) + last = sector; + count++; + } + } + + if (first + conf->chunk_sectors * (count - 1) != last) + goto overlap; + } + if (!forwrite || previous) clear_bit(STRIPE_BATCH_READY, &sh->state); @@ -7208,6 +7259,13 @@ static int raid5_run(struct mddev *mddev) BUG_ON(mddev->delta_disks != 0); } + if (test_bit(MD_HAS_JOURNAL, &mddev->flags) && + test_bit(MD_HAS_PPL, &mddev->flags)) { + pr_warn("md/raid:%s: using journal device and PPL not allowed - disabling PPL\n", + mdname(mddev)); + clear_bit(MD_HAS_PPL, &mddev->flags); + } + if (mddev->private == NULL) conf = setup_conf(mddev); else @@ -7689,7 +7747,7 @@ static int raid5_resize(struct mddev *mddev, sector_t sectors) sector_t newsize; struct r5conf *conf = mddev->private; - if (conf->log) + if (conf->log || raid5_has_ppl(conf)) return -EINVAL; sectors &= ~((sector_t)conf->chunk_sectors - 1); newsize = raid5_size(mddev, sectors, mddev->raid_disks); @@ -7740,7 +7798,7 @@ static int check_reshape(struct mddev *mddev) { struct r5conf *conf = mddev->private; - if (conf->log) + if (conf->log || raid5_has_ppl(conf)) return -EINVAL; if (mddev->delta_disks == 0 && mddev->new_layout == mddev->layout && diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index 6dd295a..ba5b7a3 100644 --- a/drivers/md/raid5.h +++ b/drivers/md/raid5.h @@ -224,10 +224,16 @@ struct stripe_head { spinlock_t batch_lock; /* only header's lock is useful */ struct list_head batch_list; /* protected by head's batch lock*/ - struct r5l_io_unit *log_io; + union { + struct r5l_io_unit *log_io; + struct ppl_io_unit *ppl_io; + }; + struct list_head log_list; sector_t log_start; /* first meta block on the journal */ struct list_head r5c; /* for r5c_cache->stripe_in_journal */ + + struct page *ppl_page; /* partial parity of this stripe */ /** * struct stripe_operations * @target - STRIPE_OP_COMPUTE_BLK target @@ -400,6 +406,7 @@ enum { STRIPE_OP_BIODRAIN, STRIPE_OP_RECONSTRUCT, STRIPE_OP_CHECK, + STRIPE_OP_PARTIAL_PARITY, }; /* @@ -696,6 +703,7 @@ struct r5conf { int group_cnt; int worker_cnt_per_group; struct r5l_log *log; + void *log_private; spinlock_t pending_bios_lock; bool batch_bio_dispatch; diff --git a/include/uapi/linux/raid/md_p.h b/include/uapi/linux/raid/md_p.h index fe21128..d9a1ead 100644 --- a/include/uapi/linux/raid/md_p.h +++ b/include/uapi/linux/raid/md_p.h @@ -398,4 +398,31 @@ struct r5l_meta_block { #define R5LOG_VERSION 0x1 #define R5LOG_MAGIC 0x6433c509 + +struct ppl_header_entry { + __le64 data_sector; /* raid sector of the new data */ + __le32 pp_size; /* length of partial parity */ + __le32 data_size; /* length of data */ + __le32 parity_disk; /* member disk containing parity */ + __le32 checksum; /* checksum of partial parity data for this + * entry (~crc32c) */ +} __attribute__ ((__packed__)); + +#define PPL_HEADER_SIZE 4096 +#define PPL_HDR_RESERVED 512 +#define PPL_HDR_ENTRY_SPACE \ + (PPL_HEADER_SIZE - PPL_HDR_RESERVED - 4 * sizeof(u32) - sizeof(u64)) +#define PPL_HDR_MAX_ENTRIES \ + (PPL_HDR_ENTRY_SPACE / sizeof(struct ppl_header_entry)) + +struct ppl_header { + __u8 reserved[PPL_HDR_RESERVED];/* reserved space, fill with 0xff */ + __le32 signature; /* signature (family number of volume) */ + __le32 padding; /* zero pad */ + __le64 generation; /* generation number of the header */ + __le32 entries_count; /* number of entries in entry array */ + __le32 checksum; /* checksum of the header (~crc32c) */ + struct ppl_header_entry entries[PPL_HDR_MAX_ENTRIES]; +} __attribute__ ((__packed__)); + #endif |
