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Commit 06e3c817 authored by Dan Williams's avatar Dan Williams Committed by NeilBrown
Browse files

md: add 'recovery_start' per-device sysfs attribute 



Enable external metadata arrays to manage rebuild checkpointing via a
md/dev-XXX/recovery_start attribute which reflects rdev->recovery_offset

Also update resync_start_store to allow 'none' to be written, for
consistency.

Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.de>
parent 4e59ca7d

Documentation/md.txt

+23 −4
Original line number Diff line number Diff line
@@ -233,9 +233,9 @@ All md devices contain: 


  resync_start

     The point at which resync should start.  If no resync is needed,

     this will be a very large number.  At array creation it will

     default to 0, though starting the array as 'clean' will

     set it much larger.

     this will be a very large number (or 'none' since 2.6.30-rc1).  At

     array creation it will default to 0, though starting the array as

     'clean' will set it much larger.



   new_dev

     This file can be written but not read.  The value written should
@@ -379,8 +379,9 @@ Each directory contains: 
	Writing "writemostly" sets the writemostly flag.

	Writing "-writemostly" clears the writemostly flag.

	Writing "blocked" sets the "blocked" flag.

	Writing "-blocked" clear the "blocked" flag and allows writes

	Writing "-blocked" clears the "blocked" flag and allows writes

		to complete.

	Writing "in_sync" sets the in_sync flag.



	This file responds to select/poll. Any change to 'faulty'

	or 'blocked' causes an event.
@@ -417,6 +418,24 @@ Each directory contains: 
        array.  If a value less than the current component_size is

        written, it will be rejected.



      recovery_start



        When the device is not 'in_sync', this records the number of

	sectors from the start of the device which are known to be

	correct.  This is normally zero, but during a recovery

	operation is will steadily increase, and if the recovery is

	interrupted, restoring this value can cause recovery to

	avoid repeating the earlier blocks.  With v1.x metadata, this

	value is saved and restored automatically.



	This can be set whenever the device is not an active member of

	the array, either before the array is activated, or before

	the 'slot' is set.



	Setting this to 'none' is equivalent to setting 'in_sync'.

	Setting to any other value also clears the 'in_sync' flag.

	





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

in the array.  These are named

drivers/md/md.c

+40 −1
Original line number Diff line number Diff line
@@ -2551,12 +2551,49 @@ rdev_size_store(mdk_rdev_t *rdev, const char *buf, size_t len) 
static struct rdev_sysfs_entry rdev_size =

__ATTR(size, S_IRUGO|S_IWUSR, rdev_size_show, rdev_size_store);





static ssize_t recovery_start_show(mdk_rdev_t *rdev, char *page)

{

	unsigned long long recovery_start = rdev->recovery_offset;



	if (test_bit(In_sync, &rdev->flags) ||

	    recovery_start == MaxSector)

		return sprintf(page, "none\n");



	return sprintf(page, "%llu\n", recovery_start);

}



static ssize_t recovery_start_store(mdk_rdev_t *rdev, const char *buf, size_t len)

{

	unsigned long long recovery_start;



	if (cmd_match(buf, "none"))

		recovery_start = MaxSector;

	else if (strict_strtoull(buf, 10, &recovery_start))

		return -EINVAL;



	if (rdev->mddev->pers &&

	    rdev->raid_disk >= 0)

		return -EBUSY;



	rdev->recovery_offset = recovery_start;

	if (recovery_start == MaxSector)

		set_bit(In_sync, &rdev->flags);

	else

		clear_bit(In_sync, &rdev->flags);

	return len;

}



static struct rdev_sysfs_entry rdev_recovery_start =

__ATTR(recovery_start, S_IRUGO|S_IWUSR, recovery_start_show, recovery_start_store);



static struct attribute *rdev_default_attrs[] = {

	&rdev_state.attr,

	&rdev_errors.attr,

	&rdev_slot.attr,

	&rdev_offset.attr,

	&rdev_size.attr,

	&rdev_recovery_start.attr,

	NULL,

};

static ssize_t
@@ -3101,7 +3138,9 @@ resync_start_store(mddev_t *mddev, const char *buf, size_t len) 


	if (mddev->pers)

		return -EBUSY;

	if (!*buf || (*e && *e != '\n'))

	if (cmd_match(buf, "none"))

		n = MaxSector;

	else if (!*buf || (*e && *e != '\n'))

		return -EINVAL;



	mddev->recovery_cp = n;