Song Liu <songliubraving@xxxxxx> writes: > Summary: > To save life time of journal device, we can config the device to > bypass journal writes for full stripe write. This is configured by: > > echo "yes" > /sys/block/mdX/md/r5l_bypass_full_stripe > > and > > echo "no" > /sys/block/mdX/md/r5l_bypass_full_stripe > > For file system integrity, full stripe with REQ_FUA will still > write to journal first. > > This patch applies on top of Shaohua's most recent patches: > > http://marc.info/?l=linux-raid&m=144122700510667 This just re-introduces the write hole. You have no guarantee that all of the writes will complete before a crash, but some might. So after a crash on a degraded array, you still get unreliable data. NeilBrown > > Signed-off-by: Song Liu <songliubraving@xxxxxx> > Reviewed-by: Shaohua Li <shli@xxxxxx> > --- > drivers/md/raid5-cache.c | 20 +++++++++++++++++ > drivers/md/raid5.c | 56 ++++++++++++++++++++++++++++++++++++++++++++++++ > drivers/md/raid5.h | 2 ++ > 3 files changed, 78 insertions(+) > > diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c > index 410b85b..0c3ddc5 100644 > --- a/drivers/md/raid5-cache.c > +++ b/drivers/md/raid5-cache.c > @@ -82,6 +82,8 @@ struct r5l_log { > > struct list_head no_space_stripes; /* pending stripes, log has no space */ > spinlock_t no_space_stripes_lock; > + > + int bypass_full_stripe; > }; > > /* > @@ -438,6 +440,7 @@ int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh) > int meta_size; > int reserve; > int i; > + int fua = 0; > > if (!log) > return -EAGAIN; > @@ -453,6 +456,8 @@ int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh) > void *addr; > if (!test_bit(R5_Wantwrite, &sh->dev[i].flags)) > continue; > + if (test_bit(R5_WantFUA, &sh->dev[i].flags)) > + fua = 1; > write_disks++; > /* checksum is already calculated in last run */ > if (test_bit(STRIPE_LOG_TRAPPED, &sh->state)) > @@ -462,6 +467,10 @@ int r5l_write_stripe(struct r5l_log *log, struct stripe_head *sh) > addr, PAGE_SIZE); > kunmap_atomic(addr); > } > + > + if (log->bypass_full_stripe && (write_disks == sh->disks) && (!fua)) > + return -EAGAIN; /* bypass journal device */ > + > parity_pages = 1 + !!(sh->qd_idx >= 0); > data_pages = write_disks - parity_pages; > > @@ -520,6 +529,16 @@ int r5l_handle_flush_request(struct r5l_log *log, struct bio *bio) > return -EAGAIN; > } > > +int r5l_get_bypass_full_stripe(struct r5l_log *log) > +{ > + return log->bypass_full_stripe; > +} > + > +void r5l_set_bypass_full_stripe(struct r5l_log *log, int val) > +{ > + log->bypass_full_stripe = val; > +} > + > /* This will run after log space is reclaimed */ > static void r5l_run_no_space_stripes(struct r5l_log *log) > { > @@ -1105,6 +1124,7 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev) > if (!log->io_kc) > goto io_kc; > > + log->bypass_full_stripe = 0; > log->reclaim_thread = md_register_thread(r5l_reclaim_thread, > log->rdev->mddev, "reclaim"); > if (!log->reclaim_thread) > diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c > index 394cdf8..5781987 100644 > --- a/drivers/md/raid5.c > +++ b/drivers/md/raid5.c > @@ -6223,6 +6223,61 @@ raid5_group_thread_cnt = __ATTR(group_thread_cnt, S_IRUGO | S_IWUSR, > raid5_show_group_thread_cnt, > raid5_store_group_thread_cnt); > > +static ssize_t > +r5l_show_bypass_full_stripe(struct mddev *mddev, char *page) > +{ > + struct r5conf *conf; > + int ret = 0; > + > + spin_lock(&mddev->lock); > + conf = mddev->private; > + if (conf) { > + if (conf->log) > + ret = sprintf(page, "%s\n", > + r5l_get_bypass_full_stripe(conf->log) ? "yes" : "no"); > + else > + ret = sprintf(page, "n/a\n"); > + } > + spin_unlock(&mddev->lock); > + return ret; > +} > + > +static ssize_t > +r5l_store_bypass_full_stripe(struct mddev *mddev, const char *page, size_t len) > +{ > + struct r5conf *conf; > + int err = 0; > + int val; > + > + if (strncmp(page, "yes", 3) == 0 && > + (page[3] == '\n' || page[3] == '\0')) > + val = 1; > + else if (strncmp(page, "no", 2) == 0 && > + (page[2] == '\n' || page[2] == '\0')) > + val = 0; > + else > + return -EINVAL; > + > + mddev_suspend(mddev); > + spin_lock(&mddev->lock); > + conf = mddev->private; > + if (conf) { > + if (conf->log) { > + r5l_set_bypass_full_stripe(conf->log, val); > + } else > + err = -EINVAL; > + } else > + err = -ENODEV; > + spin_unlock(&mddev->lock); > + mddev_resume(mddev); > + return err ?: len; > +} > + > +static struct md_sysfs_entry > +r5l_bypass_full_stripe = __ATTR(r5l_bypass_full_stripe, S_IRUGO | S_IWUSR, > + r5l_show_bypass_full_stripe, > + r5l_store_bypass_full_stripe); > + > static struct attribute *raid5_attrs[] = { > &raid5_stripecache_size.attr, > &raid5_stripecache_active.attr, > @@ -6230,6 +6285,7 @@ static struct attribute *raid5_attrs[] = { > &raid5_group_thread_cnt.attr, > &raid5_skip_copy.attr, > &raid5_rmw_level.attr, > + &r5l_bypass_full_stripe.attr, > NULL, > }; > static struct attribute_group raid5_attrs_group = { > diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h > index e6b9a40..c1f6935 100644 > --- a/drivers/md/raid5.h > +++ b/drivers/md/raid5.h > @@ -630,4 +630,6 @@ extern void r5l_write_stripe_run(struct r5l_log *log); > extern void r5l_flush_stripe_to_raid(struct r5l_log *log); > extern void r5l_stripe_write_finished(struct stripe_head *sh); > extern int r5l_handle_flush_request(struct r5l_log *log, struct bio *bio); > +extern int r5l_get_bypass_full_stripe(struct r5l_log *log); > +extern void r5l_set_bypass_full_stripe(struct r5l_log *log, int val); > #endif > -- > 1.8.1
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