[PATCH] md: allow md array component size to be accessed and set via sysfs
Signed-off-by: Neil Brown <neilb@suse.de>
Acked-by: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 9e57e97..d568ab4 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1820,6 +1820,44 @@
static ssize_t
+size_show(mddev_t *mddev, char *page)
+{
+ return sprintf(page, "%llu\n", (unsigned long long)mddev->size);
+}
+
+static int update_size(mddev_t *mddev, unsigned long size);
+
+static ssize_t
+size_store(mddev_t *mddev, const char *buf, size_t len)
+{
+ /* If array is inactive, we can reduce the component size, but
+ * not increase it (except from 0).
+ * If array is active, we can try an on-line resize
+ */
+ char *e;
+ int err = 0;
+ unsigned long long size = simple_strtoull(buf, &e, 10);
+ if (!*buf || *buf == '\n' ||
+ (*e && *e != '\n'))
+ return -EINVAL;
+
+ if (mddev->pers) {
+ err = update_size(mddev, size);
+ md_update_sb(mddev);
+ } else {
+ if (mddev->size == 0 ||
+ mddev->size > size)
+ mddev->size = size;
+ else
+ err = -ENOSPC;
+ }
+ return err ? err : len;
+}
+
+static struct md_sysfs_entry md_size =
+__ATTR(component_size, 0644, size_show, size_store);
+
+static ssize_t
action_show(mddev_t *mddev, char *page)
{
char *type = "idle";
@@ -1887,6 +1925,7 @@
&md_level.attr,
&md_raid_disks.attr,
&md_chunk_size.attr,
+ &md_size.attr,
NULL,
};
@@ -3005,6 +3044,54 @@
return 0;
}
+static int update_size(mddev_t *mddev, unsigned long size)
+{
+ mdk_rdev_t * rdev;
+ int rv;
+ struct list_head *tmp;
+
+ if (mddev->pers->resize == NULL)
+ return -EINVAL;
+ /* The "size" is the amount of each device that is used.
+ * This can only make sense for arrays with redundancy.
+ * linear and raid0 always use whatever space is available
+ * We can only consider changing the size if no resync
+ * or reconstruction is happening, and if the new size
+ * is acceptable. It must fit before the sb_offset or,
+ * if that is <data_offset, it must fit before the
+ * size of each device.
+ * If size is zero, we find the largest size that fits.
+ */
+ if (mddev->sync_thread)
+ return -EBUSY;
+ ITERATE_RDEV(mddev,rdev,tmp) {
+ sector_t avail;
+ int fit = (size == 0);
+ if (rdev->sb_offset > rdev->data_offset)
+ avail = (rdev->sb_offset*2) - rdev->data_offset;
+ else
+ avail = get_capacity(rdev->bdev->bd_disk)
+ - rdev->data_offset;
+ if (fit && (size == 0 || size > avail/2))
+ size = avail/2;
+ if (avail < ((sector_t)size << 1))
+ return -ENOSPC;
+ }
+ rv = mddev->pers->resize(mddev, (sector_t)size *2);
+ if (!rv) {
+ struct block_device *bdev;
+
+ bdev = bdget_disk(mddev->gendisk, 0);
+ if (bdev) {
+ down(&bdev->bd_inode->i_sem);
+ i_size_write(bdev->bd_inode, mddev->array_size << 10);
+ up(&bdev->bd_inode->i_sem);
+ bdput(bdev);
+ }
+ }
+ return rv;
+}
+
/*
* update_array_info is used to change the configuration of an
* on-line array.
@@ -3053,49 +3140,9 @@
else
return mddev->pers->reconfig(mddev, info->layout, -1);
}
- if (mddev->size != info->size) {
- mdk_rdev_t * rdev;
- struct list_head *tmp;
- if (mddev->pers->resize == NULL)
- return -EINVAL;
- /* The "size" is the amount of each device that is used.
- * This can only make sense for arrays with redundancy.
- * linear and raid0 always use whatever space is available
- * We can only consider changing the size if no resync
- * or reconstruction is happening, and if the new size
- * is acceptable. It must fit before the sb_offset or,
- * if that is <data_offset, it must fit before the
- * size of each device.
- * If size is zero, we find the largest size that fits.
- */
- if (mddev->sync_thread)
- return -EBUSY;
- ITERATE_RDEV(mddev,rdev,tmp) {
- sector_t avail;
- int fit = (info->size == 0);
- if (rdev->sb_offset > rdev->data_offset)
- avail = (rdev->sb_offset*2) - rdev->data_offset;
- else
- avail = get_capacity(rdev->bdev->bd_disk)
- - rdev->data_offset;
- if (fit && (info->size == 0 || info->size > avail/2))
- info->size = avail/2;
- if (avail < ((sector_t)info->size << 1))
- return -ENOSPC;
- }
- rv = mddev->pers->resize(mddev, (sector_t)info->size *2);
- if (!rv) {
- struct block_device *bdev;
+ if (mddev->size != info->size)
+ rv = update_size(mddev, info->size);
- bdev = bdget_disk(mddev->gendisk, 0);
- if (bdev) {
- down(&bdev->bd_inode->i_sem);
- i_size_write(bdev->bd_inode, mddev->array_size << 10);
- up(&bdev->bd_inode->i_sem);
- bdput(bdev);
- }
- }
- }
if (mddev->raid_disks != info->raid_disks) {
/* change the number of raid disks */
if (mddev->pers->reshape == NULL)