Commit 664aed04 authored by Artur Paszkiewicz's avatar Artur Paszkiewicz Committed by Shaohua Li
Browse files

md: add sysfs entries for PPL 



Add 'consistency_policy' attribute for array. It indicates how the array
maintains consistency in case of unexpected shutdown.

Add 'ppl_sector' and 'ppl_size' for rdev, which describe the location
and size of the PPL space on the device. They can't be changed for
active members if the array is started and PPL is enabled, so in the
setter functions only basic checks are performed. More checks are done
in ppl_validate_rdev() when starting the log.

These attributes are writable to allow enabling PPL for external
metadata arrays and (later) to enable/disable PPL for a running array.

Signed-off-by: default avatarArtur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent 3418d036

Documentation/admin-guide/md.rst

+29 −3
Original line number Diff line number Diff line
@@ -401,7 +401,30 @@ All md devices contain: 
     once the array becomes non-degraded, and this fact has been

     recorded in the metadata.



  consistency_policy

     This indicates how the array maintains consistency in case of unexpected

     shutdown. It can be:



     none

       Array has no redundancy information, e.g. raid0, linear.



     resync

       Full resync is performed and all redundancy is regenerated when the

       array is started after unclean shutdown.



     bitmap

       Resync assisted by a write-intent bitmap.



     journal

       For raid4/5/6, journal device is used to log transactions and replay

       after unclean shutdown.



     ppl

       For raid5 only, Partial Parity Log is used to close the write hole and

       eliminate resync.



     The accepted values when writing to this file are ``ppl`` and ``resync``,

     used to enable and disable PPL.





As component devices are added to an md array, they appear in the ``md``
@@ -563,6 +586,9 @@ Each directory contains: 
	adds bad blocks without acknowledging them. This is largely

	for testing.



      ppl_sector, ppl_size

        Location and size (in sectors) of the space used for Partial Parity Log

        on this device.





An active md device will also contain an entry for each active device

drivers/md/md.c

+115 −0
Original line number Diff line number Diff line
@@ -3150,6 +3150,78 @@ static ssize_t ubb_store(struct md_rdev *rdev, const char *page, size_t len) 
static struct rdev_sysfs_entry rdev_unack_bad_blocks =

__ATTR(unacknowledged_bad_blocks, S_IRUGO|S_IWUSR, ubb_show, ubb_store);



static ssize_t

ppl_sector_show(struct md_rdev *rdev, char *page)

{

	return sprintf(page, "%llu\n", (unsigned long long)rdev->ppl.sector);

}



static ssize_t

ppl_sector_store(struct md_rdev *rdev, const char *buf, size_t len)

{

	unsigned long long sector;



	if (kstrtoull(buf, 10, &sector) < 0)

		return -EINVAL;

	if (sector != (sector_t)sector)

		return -EINVAL;



	if (rdev->mddev->pers && test_bit(MD_HAS_PPL, &rdev->mddev->flags) &&

	    rdev->raid_disk >= 0)

		return -EBUSY;



	if (rdev->mddev->persistent) {

		if (rdev->mddev->major_version == 0)

			return -EINVAL;

		if ((sector > rdev->sb_start &&

		     sector - rdev->sb_start > S16_MAX) ||

		    (sector < rdev->sb_start &&

		     rdev->sb_start - sector > -S16_MIN))

			return -EINVAL;

		rdev->ppl.offset = sector - rdev->sb_start;

	} else if (!rdev->mddev->external) {

		return -EBUSY;

	}

	rdev->ppl.sector = sector;

	return len;

}



static struct rdev_sysfs_entry rdev_ppl_sector =

__ATTR(ppl_sector, S_IRUGO|S_IWUSR, ppl_sector_show, ppl_sector_store);



static ssize_t

ppl_size_show(struct md_rdev *rdev, char *page)

{

	return sprintf(page, "%u\n", rdev->ppl.size);

}



static ssize_t

ppl_size_store(struct md_rdev *rdev, const char *buf, size_t len)

{

	unsigned int size;



	if (kstrtouint(buf, 10, &size) < 0)

		return -EINVAL;



	if (rdev->mddev->pers && test_bit(MD_HAS_PPL, &rdev->mddev->flags) &&

	    rdev->raid_disk >= 0)

		return -EBUSY;



	if (rdev->mddev->persistent) {

		if (rdev->mddev->major_version == 0)

			return -EINVAL;

		if (size > U16_MAX)

			return -EINVAL;

	} else if (!rdev->mddev->external) {

		return -EBUSY;

	}

	rdev->ppl.size = size;

	return len;

}



static struct rdev_sysfs_entry rdev_ppl_size =

__ATTR(ppl_size, S_IRUGO|S_IWUSR, ppl_size_show, ppl_size_store);



static struct attribute *rdev_default_attrs[] = {

	&rdev_state.attr,

	&rdev_errors.attr,
@@ -3160,6 +3232,8 @@ static struct attribute *rdev_default_attrs[] = { 
	&rdev_recovery_start.attr,

	&rdev_bad_blocks.attr,

	&rdev_unack_bad_blocks.attr,

	&rdev_ppl_sector.attr,

	&rdev_ppl_size.attr,

	NULL,

};

static ssize_t
@@ -4896,6 +4970,46 @@ static struct md_sysfs_entry md_array_size = 
__ATTR(array_size, S_IRUGO|S_IWUSR, array_size_show,

       array_size_store);



static ssize_t

consistency_policy_show(struct mddev *mddev, char *page)

{

	int ret;



	if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {

		ret = sprintf(page, "journal\n");

	} else if (test_bit(MD_HAS_PPL, &mddev->flags)) {

		ret = sprintf(page, "ppl\n");

	} else if (mddev->bitmap) {

		ret = sprintf(page, "bitmap\n");

	} else if (mddev->pers) {

		if (mddev->pers->sync_request)

			ret = sprintf(page, "resync\n");

		else

			ret = sprintf(page, "none\n");

	} else {

		ret = sprintf(page, "unknown\n");

	}



	return ret;

}



static ssize_t

consistency_policy_store(struct mddev *mddev, const char *buf, size_t len)

{

	if (mddev->pers) {

		return -EBUSY;

	} else if (mddev->external && strncmp(buf, "ppl", 3) == 0) {

		set_bit(MD_HAS_PPL, &mddev->flags);

		return len;

	} else {

		return -EINVAL;

	}

}



static struct md_sysfs_entry md_consistency_policy =

__ATTR(consistency_policy, S_IRUGO | S_IWUSR, consistency_policy_show,

       consistency_policy_store);



static struct attribute *md_default_attrs[] = {

	&md_level.attr,

	&md_layout.attr,
@@ -4911,6 +5025,7 @@ static struct attribute *md_default_attrs[] = { 
	&md_reshape_direction.attr,

	&md_array_size.attr,

	&max_corr_read_errors.attr,

	&md_consistency_policy.attr,

	NULL,

};

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