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md: allow reshape_position for md arrays to be set via sysfs 

"reshape_position" records how much progress has been made on a "reshape"
(adding drives, changing layout or chunksize).

When it is set, the number of drives, layout and chunksize can have
two possible values, an old an a new.

So allow these different values to be visible, and allow both old and new to
be set: Set the old ones first, then the reshape_position, then the new
values.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
NeilBrown 2007-05-09 02:35:38 -07:00 committed by Linus Torvalds
parent 42b9bebe3f
commit 08a02ecd28
2 changed files with 107 additions and 35 deletions
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72
Documentation/md.txt
View File

@ -178,6 +178,21 @@ All md devices contain:
The size should be at least PAGE_SIZE (4k) and should be a power
of 2. This can only be set while assembling an array
layout
The "layout" for the array for the particular level. This is
simply a number that is interpretted differently by different
levels. It can be written while assembling an array.
reshape_position
This is either "none" or a sector number within the devices of
the array where "reshape" is up to. If this is set, the three
attributes mentioned above (raid_disks, chunk_size, layout) can
potentially have 2 values, an old and a new value. If these
values differ, reading the attribute returns
new (old)
and writing will effect the 'new' value, leaving the 'old'
unchanged.
component_size
For arrays with data redundancy (i.e. not raid0, linear, faulty,
multipath), all components must be the same size - or at least
@ -193,11 +208,6 @@ All md devices contain:
1.2 (newer format in varying locations) or "none" indicating that
the kernel isn't managing metadata at all.
layout
The "layout" for the array for the particular level. This is
simply a number that is interpretted differently by different
levels. It can be written while assembling an array.
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
@ -259,29 +269,6 @@ All md devices contain:
like active, but no writes have been seen for a while (safe_mode_delay).
sync_speed_min
sync_speed_max
This are similar to /proc/sys/dev/raid/speed_limit_{min,max}
however they only apply to the particular array.
If no value has been written to these, of if the word 'system'
is written, then the system-wide value is used. If a value,
in kibibytes-per-second is written, then it is used.
When the files are read, they show the currently active value
followed by "(local)" or "(system)" depending on whether it is
a locally set or system-wide value.
sync_completed
This shows the number of sectors that have been completed of
whatever the current sync_action is, followed by the number of
sectors in total that could need to be processed. The two
numbers are separated by a '/' thus effectively showing one
value, a fraction of the process that is complete.
sync_speed
This shows the current actual speed, in K/sec, of the current
sync_action. It is averaged over the last 30 seconds.
As component devices are added to an md array, they appear in the 'md'
directory as new directories named
dev-XXX
@ -412,6 +399,35 @@ also have
Note that the numbers are 'bit' numbers, not 'block' numbers.
They should be scaled by the bitmap_chunksize.
sync_speed_min
sync_speed_max
This are similar to /proc/sys/dev/raid/speed_limit_{min,max}
however they only apply to the particular array.
If no value has been written to these, of if the word 'system'
is written, then the system-wide value is used. If a value,
in kibibytes-per-second is written, then it is used.
When the files are read, they show the currently active value
followed by "(local)" or "(system)" depending on whether it is
a locally set or system-wide value.
sync_completed
This shows the number of sectors that have been completed of
whatever the current sync_action is, followed by the number of
sectors in total that could need to be processed. The two
numbers are separated by a '/' thus effectively showing one
value, a fraction of the process that is complete.
sync_speed
This shows the current actual speed, in K/sec, of the current
sync_action. It is averaged over the last 30 seconds.
suspend_lo
suspend_hi
The two values, given as numbers of sectors, indicate a range
within the array where IO will be blocked. This is currently
only supported for raid4/5/6.
Each active md device may also have attributes specific to the
personality module that manages it.
These are specific to the implementation of the module and could

70
drivers/md/md.c
View File

@ -274,6 +274,7 @@ static mddev_t * mddev_find(dev_t unit)
atomic_set(&new->active, 1);
spin_lock_init(&new->write_lock);
init_waitqueue_head(&new->sb_wait);
new->reshape_position = MaxSector;
new->queue = blk_alloc_queue(GFP_KERNEL);
if (!new->queue) {
@ -2242,6 +2243,10 @@ static ssize_t
layout_show(mddev_t *mddev, char *page)
{
/* just a number, not meaningful for all levels */
if (mddev->reshape_position != MaxSector &&
mddev->layout != mddev->new_layout)
return sprintf(page, "%d (%d)\n",
mddev->new_layout, mddev->layout);
return sprintf(page, "%d\n", mddev->layout);
}
@ -2250,13 +2255,16 @@ layout_store(mddev_t *mddev, const char *buf, size_t len)
{
char *e;
unsigned long n = simple_strtoul(buf, &e, 10);
if (mddev->pers)
return -EBUSY;
if (!*buf || (*e && *e != '\n'))
return -EINVAL;
mddev->layout = n;
if (mddev->pers)
return -EBUSY;
if (mddev->reshape_position != MaxSector)
mddev->new_layout = n;
else
mddev->layout = n;
return len;
}
static struct md_sysfs_entry md_layout =
@ -2268,6 +2276,10 @@ raid_disks_show(mddev_t *mddev, char *page)
{
if (mddev->raid_disks == 0)
return 0;
if (mddev->reshape_position != MaxSector &&
mddev->delta_disks != 0)
return sprintf(page, "%d (%d)\n", mddev->raid_disks,
mddev->raid_disks - mddev->delta_disks);
return sprintf(page, "%d\n", mddev->raid_disks);
}
@ -2285,7 +2297,11 @@ raid_disks_store(mddev_t *mddev, const char *buf, size_t len)
if (mddev->pers)
rv = update_raid_disks(mddev, n);
else
else if (mddev->reshape_position != MaxSector) {
int olddisks = mddev->raid_disks - mddev->delta_disks;
mddev->delta_disks = n - olddisks;
mddev->raid_disks = n;
} else
mddev->raid_disks = n;
return rv ? rv : len;
}
@ -2295,6 +2311,10 @@ __ATTR(raid_disks, S_IRUGO|S_IWUSR, raid_disks_show, raid_disks_store);
static ssize_t
chunk_size_show(mddev_t *mddev, char *page)
{
if (mddev->reshape_position != MaxSector &&
mddev->chunk_size != mddev->new_chunk)
return sprintf(page, "%d (%d)\n", mddev->new_chunk,
mddev->chunk_size);
return sprintf(page, "%d\n", mddev->chunk_size);
}
@ -2305,12 +2325,15 @@ chunk_size_store(mddev_t *mddev, const char *buf, size_t len)
char *e;
unsigned long n = simple_strtoul(buf, &e, 10);
if (mddev->pers)
return -EBUSY;
if (!*buf || (*e && *e != '\n'))
return -EINVAL;
mddev->chunk_size = n;
if (mddev->pers)
return -EBUSY;
else if (mddev->reshape_position != MaxSector)
mddev->new_chunk = n;
else
mddev->chunk_size = n;
return len;
}
static struct md_sysfs_entry md_chunk_size =
@ -2896,6 +2919,37 @@ suspend_hi_store(mddev_t *mddev, const char *buf, size_t len)
static struct md_sysfs_entry md_suspend_hi =
__ATTR(suspend_hi, S_IRUGO|S_IWUSR, suspend_hi_show, suspend_hi_store);
static ssize_t
reshape_position_show(mddev_t *mddev, char *page)
{
if (mddev->reshape_position != MaxSector)
return sprintf(page, "%llu\n",
(unsigned long long)mddev->reshape_position);
strcpy(page, "none\n");
return 5;
}
static ssize_t
reshape_position_store(mddev_t *mddev, const char *buf, size_t len)
{
char *e;
unsigned long long new = simple_strtoull(buf, &e, 10);
if (mddev->pers)
return -EBUSY;
if (buf == e || (*e && *e != '\n'))
return -EINVAL;
mddev->reshape_position = new;
mddev->delta_disks = 0;
mddev->new_level = mddev->level;
mddev->new_layout = mddev->layout;
mddev->new_chunk = mddev->chunk_size;
return len;
}
static struct md_sysfs_entry md_reshape_position =
__ATTR(reshape_position, S_IRUGO|S_IWUSR, reshape_position_show,
reshape_position_store);
static struct attribute *md_default_attrs[] = {
&md_level.attr,
@ -2908,6 +2962,7 @@ static struct attribute *md_default_attrs[] = {
&md_new_device.attr,
&md_safe_delay.attr,
&md_array_state.attr,
&md_reshape_position.attr,
NULL,
};
@ -3446,6 +3501,7 @@ static int do_md_stop(mddev_t * mddev, int mode)
mddev->size = 0;
mddev->raid_disks = 0;
mddev->recovery_cp = 0;
mddev->reshape_position = MaxSector;
} else if (mddev->pers)
printk(KERN_INFO "md: %s switched to read-only mode.\n",