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authorArtur Paszkiewicz2017-03-09 09:59:59 +0100
committerShaohua Li2017-03-17 00:55:54 +0100
commit3418d036c81dcb604b7c7c71b209d5890a8418aa (patch)
treed02a31103e09f82858bf149ebcb511e12ed6065a /drivers/md/raid5-log.h
parentraid5: separate header for log functions (diff)
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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>
Diffstat (limited to 'drivers/md/raid5-log.h')
-rw-r--r--drivers/md/raid5-log.h24
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/md/raid5-log.h b/drivers/md/raid5-log.h
index 2da4bd3bbd79..a67fb58513b9 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;
}