raid5-ppl: Partial Parity Log write logging implementation
Implement the calculation of partial parity for a stripe and PPL write logging functionality. The description of PPL is added to the documentation. More details can be found in the comments in raid5-ppl.c. Attach a page for holding the partial parity data to stripe_head. Allocate it only if mddev has the MD_HAS_PPL flag set. Partial parity is the xor of not modified data chunks of a stripe and is calculated as follows: - reconstruct-write case: xor data from all not updated disks in a stripe - read-modify-write case: xor old data and parity from all updated disks in a stripe Implement it using the async_tx API and integrate into raid_run_ops(). It must be called when we still have access to old data, so do it when STRIPE_OP_BIODRAIN is set, but before ops_run_prexor5(). The result is stored into sh->ppl_page. Partial parity is not meaningful for full stripe write and is not stored in the log or used for recovery, so don't attempt to calculate it when stripe has STRIPE_FULL_WRITE. Put the PPL metadata structures to md_p.h because userspace tools (mdadm) will also need to read/write PPL. Warn about using PPL with enabled disk volatile write-back cache for now. It can be removed once disk cache flushing before writing PPL is implemented. Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com> Signed-off-by: Shaohua Li <shli@fb.com>zero-colors
Artur Paszkiewicz
Shaohua Li
parent
ff875738ed
commit
3418d036c8
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@ -0,0 +1,44 @@
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Partial Parity Log
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Partial Parity Log (PPL) is a feature available for RAID5 arrays. The issue
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addressed by PPL is that after a dirty shutdown, parity of a particular stripe
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may become inconsistent with data on other member disks. If the array is also
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in degraded state, there is no way to recalculate parity, because one of the
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disks is missing. This can lead to silent data corruption when rebuilding the
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array or using it is as degraded - data calculated from parity for array blocks
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that have not been touched by a write request during the unclean shutdown can
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be incorrect. Such condition is known as the RAID5 Write Hole. Because of
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this, md by default does not allow starting a dirty degraded array.
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Partial parity for a write operation is the XOR of stripe data chunks not
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modified by this write. It is just enough data needed for recovering from the
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write hole. XORing partial parity with the modified chunks produces parity for
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the stripe, consistent with its state before the write operation, regardless of
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which chunk writes have completed. If one of the not modified data disks of
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this stripe is missing, this updated parity can be used to recover its
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contents. PPL recovery is also performed when starting an array after an
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unclean shutdown and all disks are available, eliminating the need to resync
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the array. Because of this, using write-intent bitmap and PPL together is not
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supported.
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When handling a write request PPL writes partial parity before new data and
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parity are dispatched to disks. PPL is a distributed log - it is stored on
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array member drives in the metadata area, on the parity drive of a particular
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stripe. It does not require a dedicated journaling drive. Write performance is
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reduced by up to 30%-40% but it scales with the number of drives in the array
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and the journaling drive does not become a bottleneck or a single point of
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failure.
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Unlike raid5-cache, the other solution in md for closing the write hole, PPL is
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not a true journal. It does not protect from losing in-flight data, only from
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silent data corruption. If a dirty disk of a stripe is lost, no PPL recovery is
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performed for this stripe (parity is not updated). So it is possible to have
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arbitrary data in the written part of a stripe if that disk is lost. In such
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case the behavior is the same as in plain raid5.
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PPL is available for md version-1 metadata and external (specifically IMSM)
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metadata arrays. It can be enabled using mdadm option --consistency-policy=ppl.
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Currently, volatile write-back cache should be disabled on all member drives
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when using PPL. Otherwise it cannot guarantee consistency in case of power
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failure.
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@ -18,7 +18,7 @@ dm-cache-cleaner-y += dm-cache-policy-cleaner.o
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dm-era-y += dm-era-target.o
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dm-verity-y += dm-verity-target.o
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md-mod-y += md.o bitmap.o
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raid456-y += raid5.o raid5-cache.o
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raid456-y += raid5.o raid5-cache.o raid5-ppl.o
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# Note: link order is important. All raid personalities
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# and must come before md.o, as they each initialise
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@ -31,6 +31,20 @@ extern struct md_sysfs_entry r5c_journal_mode;
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extern void r5c_update_on_rdev_error(struct mddev *mddev);
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extern bool r5c_big_stripe_cached(struct r5conf *conf, sector_t sect);
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extern struct dma_async_tx_descriptor *
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ops_run_partial_parity(struct stripe_head *sh, struct raid5_percpu *percpu,
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struct dma_async_tx_descriptor *tx);
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extern int ppl_init_log(struct r5conf *conf);
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extern void ppl_exit_log(struct r5conf *conf);
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extern int ppl_write_stripe(struct r5conf *conf, struct stripe_head *sh);
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extern void ppl_write_stripe_run(struct r5conf *conf);
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extern void ppl_stripe_write_finished(struct stripe_head *sh);
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static inline bool raid5_has_ppl(struct r5conf *conf)
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{
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return test_bit(MD_HAS_PPL, &conf->mddev->flags);
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}
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static inline int log_stripe(struct stripe_head *sh, struct stripe_head_state *s)
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{
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struct r5conf *conf = sh->raid_conf;
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@ -45,6 +59,8 @@ static inline int log_stripe(struct stripe_head *sh, struct stripe_head_state *s
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/* caching phase */
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return r5c_cache_data(conf->log, sh);
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}
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} else if (raid5_has_ppl(conf)) {
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return ppl_write_stripe(conf, sh);
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}
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return -EAGAIN;
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@ -56,24 +72,32 @@ static inline void log_stripe_write_finished(struct stripe_head *sh)
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if (conf->log)
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r5l_stripe_write_finished(sh);
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else if (raid5_has_ppl(conf))
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ppl_stripe_write_finished(sh);
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}
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static inline void log_write_stripe_run(struct r5conf *conf)
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{
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if (conf->log)
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r5l_write_stripe_run(conf->log);
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else if (raid5_has_ppl(conf))
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ppl_write_stripe_run(conf);
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}
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static inline void log_exit(struct r5conf *conf)
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{
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if (conf->log)
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r5l_exit_log(conf);
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else if (raid5_has_ppl(conf))
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ppl_exit_log(conf);
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}
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static inline int log_init(struct r5conf *conf, struct md_rdev *journal_dev)
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{
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if (journal_dev)
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return r5l_init_log(conf, journal_dev);
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else if (raid5_has_ppl(conf))
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return ppl_init_log(conf);
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return 0;
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}
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@ -0,0 +1,703 @@
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/*
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* Partial Parity Log for closing the RAID5 write hole
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* Copyright (c) 2017, Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#include <linux/kernel.h>
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#include <linux/blkdev.h>
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#include <linux/slab.h>
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#include <linux/crc32c.h>
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#include <linux/flex_array.h>
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#include <linux/async_tx.h>
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#include <linux/raid/md_p.h>
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#include "md.h"
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#include "raid5.h"
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/*
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* PPL consists of a 4KB header (struct ppl_header) and at least 128KB for
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* partial parity data. The header contains an array of entries
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* (struct ppl_header_entry) which describe the logged write requests.
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* Partial parity for the entries comes after the header, written in the same
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* sequence as the entries:
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*
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* Header
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* entry0
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* ...
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* entryN
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* PP data
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* PP for entry0
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* ...
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* PP for entryN
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*
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* An entry describes one or more consecutive stripe_heads, up to a full
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* stripe. The modifed raid data chunks form an m-by-n matrix, where m is the
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* number of stripe_heads in the entry and n is the number of modified data
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* disks. Every stripe_head in the entry must write to the same data disks.
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* An example of a valid case described by a single entry (writes to the first
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* stripe of a 4 disk array, 16k chunk size):
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*
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* sh->sector dd0 dd1 dd2 ppl
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* +-----+-----+-----+
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* 0 | --- | --- | --- | +----+
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* 8 | -W- | -W- | --- | | pp | data_sector = 8
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* 16 | -W- | -W- | --- | | pp | data_size = 3 * 2 * 4k
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* 24 | -W- | -W- | --- | | pp | pp_size = 3 * 4k
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* +-----+-----+-----+ +----+
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*
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* data_sector is the first raid sector of the modified data, data_size is the
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* total size of modified data and pp_size is the size of partial parity for
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* this entry. Entries for full stripe writes contain no partial parity
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* (pp_size = 0), they only mark the stripes for which parity should be
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* recalculated after an unclean shutdown. Every entry holds a checksum of its
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* partial parity, the header also has a checksum of the header itself.
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*
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* A write request is always logged to the PPL instance stored on the parity
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* disk of the corresponding stripe. For each member disk there is one ppl_log
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* used to handle logging for this disk, independently from others. They are
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* grouped in child_logs array in struct ppl_conf, which is assigned to
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* r5conf->log_private.
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*
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* ppl_io_unit represents a full PPL write, header_page contains the ppl_header.
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* PPL entries for logged stripes are added in ppl_log_stripe(). A stripe_head
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* can be appended to the last entry if it meets the conditions for a valid
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* entry described above, otherwise a new entry is added. Checksums of entries
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* are calculated incrementally as stripes containing partial parity are being
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* added. ppl_submit_iounit() calculates the checksum of the header and submits
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* a bio containing the header page and partial parity pages (sh->ppl_page) for
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* all stripes of the io_unit. When the PPL write completes, the stripes
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* associated with the io_unit are released and raid5d starts writing their data
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* and parity. When all stripes are written, the io_unit is freed and the next
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* can be submitted.
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*
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* An io_unit is used to gather stripes until it is submitted or becomes full
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* (if the maximum number of entries or size of PPL is reached). Another io_unit
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* can't be submitted until the previous has completed (PPL and stripe
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* data+parity is written). The log->io_list tracks all io_units of a log
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* (for a single member disk). New io_units are added to the end of the list
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* and the first io_unit is submitted, if it is not submitted already.
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* The current io_unit accepting new stripes is always at the end of the list.
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*/
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struct ppl_conf {
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struct mddev *mddev;
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/* array of child logs, one for each raid disk */
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struct ppl_log *child_logs;
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int count;
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int block_size; /* the logical block size used for data_sector
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* in ppl_header_entry */
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u32 signature; /* raid array identifier */
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atomic64_t seq; /* current log write sequence number */
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struct kmem_cache *io_kc;
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mempool_t *io_pool;
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struct bio_set *bs;
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mempool_t *meta_pool;
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};
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struct ppl_log {
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struct ppl_conf *ppl_conf; /* shared between all log instances */
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struct md_rdev *rdev; /* array member disk associated with
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* this log instance */
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struct mutex io_mutex;
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struct ppl_io_unit *current_io; /* current io_unit accepting new data
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* always at the end of io_list */
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spinlock_t io_list_lock;
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struct list_head io_list; /* all io_units of this log */
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struct list_head no_mem_stripes;/* stripes to retry if failed to
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* allocate io_unit */
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};
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#define PPL_IO_INLINE_BVECS 32
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struct ppl_io_unit {
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struct ppl_log *log;
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struct page *header_page; /* for ppl_header */
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unsigned int entries_count; /* number of entries in ppl_header */
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unsigned int pp_size; /* total size current of partial parity */
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u64 seq; /* sequence number of this log write */
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struct list_head log_sibling; /* log->io_list */
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struct list_head stripe_list; /* stripes added to the io_unit */
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atomic_t pending_stripes; /* how many stripes not written to raid */
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bool submitted; /* true if write to log started */
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/* inline bio and its biovec for submitting the iounit */
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struct bio bio;
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struct bio_vec biovec[PPL_IO_INLINE_BVECS];
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};
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struct dma_async_tx_descriptor *
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ops_run_partial_parity(struct stripe_head *sh, struct raid5_percpu *percpu,
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struct dma_async_tx_descriptor *tx)
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{
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int disks = sh->disks;
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struct page **xor_srcs = flex_array_get(percpu->scribble, 0);
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int count = 0, pd_idx = sh->pd_idx, i;
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struct async_submit_ctl submit;
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pr_debug("%s: stripe %llu\n", __func__, (unsigned long long)sh->sector);
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/*
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* Partial parity is the XOR of stripe data chunks that are not changed
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* during the write request. Depending on available data
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* (read-modify-write vs. reconstruct-write case) we calculate it
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* differently.
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*/
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if (sh->reconstruct_state == reconstruct_state_prexor_drain_run) {
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/* rmw: xor old data and parity from updated disks */
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for (i = disks; i--;) {
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struct r5dev *dev = &sh->dev[i];
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if (test_bit(R5_Wantdrain, &dev->flags) || i == pd_idx)
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xor_srcs[count++] = dev->page;
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}
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} else if (sh->reconstruct_state == reconstruct_state_drain_run) {
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/* rcw: xor data from all not updated disks */
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for (i = disks; i--;) {
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struct r5dev *dev = &sh->dev[i];
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if (test_bit(R5_UPTODATE, &dev->flags))
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xor_srcs[count++] = dev->page;
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}
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} else {
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return tx;
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}
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init_async_submit(&submit, ASYNC_TX_FENCE|ASYNC_TX_XOR_ZERO_DST, tx,
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NULL, sh, flex_array_get(percpu->scribble, 0)
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+ sizeof(struct page *) * (sh->disks + 2));
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if (count == 1)
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tx = async_memcpy(sh->ppl_page, xor_srcs[0], 0, 0, PAGE_SIZE,
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&submit);
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else
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tx = async_xor(sh->ppl_page, xor_srcs, 0, count, PAGE_SIZE,
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&submit);
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return tx;
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}
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static struct ppl_io_unit *ppl_new_iounit(struct ppl_log *log,
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struct stripe_head *sh)
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{
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struct ppl_conf *ppl_conf = log->ppl_conf;
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struct ppl_io_unit *io;
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struct ppl_header *pplhdr;
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io = mempool_alloc(ppl_conf->io_pool, GFP_ATOMIC);
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if (!io)
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return NULL;
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memset(io, 0, sizeof(*io));
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io->log = log;
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INIT_LIST_HEAD(&io->log_sibling);
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INIT_LIST_HEAD(&io->stripe_list);
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atomic_set(&io->pending_stripes, 0);
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bio_init(&io->bio, io->biovec, PPL_IO_INLINE_BVECS);
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io->header_page = mempool_alloc(ppl_conf->meta_pool, GFP_NOIO);
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pplhdr = page_address(io->header_page);
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clear_page(pplhdr);
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memset(pplhdr->reserved, 0xff, PPL_HDR_RESERVED);
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pplhdr->signature = cpu_to_le32(ppl_conf->signature);
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io->seq = atomic64_add_return(1, &ppl_conf->seq);
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pplhdr->generation = cpu_to_le64(io->seq);
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return io;
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}
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static int ppl_log_stripe(struct ppl_log *log, struct stripe_head *sh)
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{
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struct ppl_io_unit *io = log->current_io;
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struct ppl_header_entry *e = NULL;
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struct ppl_header *pplhdr;
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int i;
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sector_t data_sector = 0;
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int data_disks = 0;
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unsigned int entry_space = (log->rdev->ppl.size << 9) - PPL_HEADER_SIZE;
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struct r5conf *conf = sh->raid_conf;
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pr_debug("%s: stripe: %llu\n", __func__, (unsigned long long)sh->sector);
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/* check if current io_unit is full */
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if (io && (io->pp_size == entry_space ||
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io->entries_count == PPL_HDR_MAX_ENTRIES)) {
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pr_debug("%s: add io_unit blocked by seq: %llu\n",
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__func__, io->seq);
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io = NULL;
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}
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/* add a new unit if there is none or the current is full */
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if (!io) {
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io = ppl_new_iounit(log, sh);
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if (!io)
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return -ENOMEM;
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spin_lock_irq(&log->io_list_lock);
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list_add_tail(&io->log_sibling, &log->io_list);
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spin_unlock_irq(&log->io_list_lock);
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log->current_io = io;
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}
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for (i = 0; i < sh->disks; i++) {
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struct r5dev *dev = &sh->dev[i];
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if (i != sh->pd_idx && test_bit(R5_Wantwrite, &dev->flags)) {
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if (!data_disks || dev->sector < data_sector)
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data_sector = dev->sector;
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data_disks++;
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}
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}
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BUG_ON(!data_disks);
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pr_debug("%s: seq: %llu data_sector: %llu data_disks: %d\n", __func__,
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io->seq, (unsigned long long)data_sector, data_disks);
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pplhdr = page_address(io->header_page);
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if (io->entries_count > 0) {
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struct ppl_header_entry *last =
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&pplhdr->entries[io->entries_count - 1];
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struct stripe_head *sh_last = list_last_entry(
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&io->stripe_list, struct stripe_head, log_list);
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u64 data_sector_last = le64_to_cpu(last->data_sector);
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u32 data_size_last = le32_to_cpu(last->data_size);
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|
||||
/*
|
||||
* 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;
|
||||
}
|
||||
|
|
@ -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 &&
|
||||
|
|
|
|||
|
|
@ -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;
|
||||
|
|
|
|||
|
|
@ -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
|
||||
|
|
|
|||
Loading…
Reference in New Issue