On Tue, Feb 21, 2017 at 08:44:01PM +0100, Artur Paszkiewicz wrote:
> Allow writing to 'consistency_policy' attribute when the array is
> active. Add a new function 'change_consistency_policy' to the
> md_personality operations structure to handle the change in the
> personality code. Values "ppl" and "resync" are accepted and
> turn PPL on and off respectively.
>
> When enabling PPL its location and size should first be set using
> 'ppl_sector' and 'ppl_size' attributes and a valid PPL header should be
> written at this location on each member device.
>
> Enabling or disabling PPL is performed under a suspended array. The
> raid5_reset_stripe_cache function frees the stripe cache and allocates
> it again in order to allocate or free the ppl_pages for the stripes in
> the stripe cache.
>
> Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@xxxxxxxxx>
> ---
> drivers/md/md.c | 12 ++++++++---
> drivers/md/md.h | 2 ++
> drivers/md/raid5-ppl.c | 4 ++++
> drivers/md/raid5.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 73 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 3ff979d538d4..b70e19513588 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -5003,14 +5003,20 @@ consistency_policy_show(struct mddev *mddev, char *page)
> static ssize_t
> consistency_policy_store(struct mddev *mddev, const char *buf, size_t len)
> {
> + int err = 0;
> +
> if (mddev->pers) {
> - return -EBUSY;
> + if (mddev->pers->change_consistency_policy)
> + err = mddev->pers->change_consistency_policy(mddev, buf);
> + else
> + err = -EBUSY;
> } else if (mddev->external && strncmp(buf, "ppl", 3) == 0) {
> set_bit(MD_HAS_PPL, &mddev->flags);
> - return len;
> } else {
> - return -EINVAL;
> + err = -EINVAL;
> }
> +
> + return err ? err : len;
> }
>
> static struct md_sysfs_entry md_consistency_policy =
> diff --git a/drivers/md/md.h b/drivers/md/md.h
> index 66a5a16e79f7..88a5155c152e 100644
> --- a/drivers/md/md.h
> +++ b/drivers/md/md.h
> @@ -548,6 +548,8 @@ struct md_personality
> /* congested implements bdi.congested_fn().
> * Will not be called while array is 'suspended' */
> int (*congested)(struct mddev *mddev, int bits);
> + /* Changes the consistency policy of an active array. */
> + int (*change_consistency_policy)(struct mddev *mddev, const char *buf);
> };
>
> struct md_sysfs_entry {
> diff --git a/drivers/md/raid5-ppl.c b/drivers/md/raid5-ppl.c
> index c2070d124849..a5c4d3333bce 100644
> --- a/drivers/md/raid5-ppl.c
> +++ b/drivers/md/raid5-ppl.c
> @@ -1095,6 +1095,10 @@ int ppl_init_log(struct r5conf *conf)
> */
> mddev->recovery_cp = MaxSector;
> set_bit(MD_SB_CHANGE_CLEAN, &mddev->sb_flags);
> + } else if (mddev->pers && ppl_conf->mismatch_count > 0) {
> + /* no mismatch allowed when enabling PPL for a running array */
> + ret = -EINVAL;
> + goto err;
> }
>
> conf->ppl = ppl_conf;
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index b17e90f06f19..754fb8e1c76f 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -8319,6 +8319,63 @@ static void *raid6_takeover(struct mddev *mddev)
> return setup_conf(mddev);
> }
>
> +static void raid5_reset_stripe_cache(struct mddev *mddev)
> +{
> + struct r5conf *conf = mddev->private;
> +
> + mutex_lock(&conf->cache_size_mutex);
> + while (conf->max_nr_stripes &&
> + drop_one_stripe(conf))
> + ;
> + while (conf->min_nr_stripes > conf->max_nr_stripes &&
> + grow_one_stripe(conf, GFP_KERNEL))
> + ;
> + mutex_unlock(&conf->cache_size_mutex);
> +}
> +
> +static int raid5_change_consistency_policy(struct mddev *mddev, const char *buf)
> +{
> + struct r5conf *conf;
> + int err;
> +
> + err = mddev_lock(mddev);
> + if (err)
> + return err;
> + conf = mddev->private;
> + if (!conf) {
> + mddev_unlock(mddev);
> + return -ENODEV;
> + }
> +
> + if (strncmp(buf, "ppl", 3) == 0 &&
> + !test_bit(MD_HAS_PPL, &mddev->flags)) {
> + mddev_suspend(mddev);
> + err = ppl_init_log(conf);
I didn't see you check if all rdev have valid ppl setting in ppl_load. Am I
missing anything? Is it possible some rdevs have ppl set, but some not. In the
case, we should just bail out.
Also check if this is raid5
Thanks,
Shaohua
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