md: 'array_size' sysfs attribute
Allow userspace to set the size of the array according to the following
semantics:
1/ size must be <= to the size returned by mddev->pers->size(mddev, 0, 0)
a) If size is set before the array is running, do_md_run will fail
if size is greater than the default size
b) A reshape attempt that reduces the default size to less than the set
array size should be blocked
2/ once userspace sets the size the kernel will not change it
3/ writing 'default' to this attribute returns control of the size to the
kernel and reverts to the size reported by the personality
Also, convert locations that need to know the default size from directly
reading ->array_sectors to <pers>_size. Resync/reshape operations
always follow the default size.
Finally, fixup other locations that read a number of 1k-blocks from
userspace to use strict_blocks_to_sectors() which checks for unsigned
long long to sector_t overflow and blocks to sectors overflow.
Reviewed-by: Andre Noll <maan@systemlinux.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 76ba69b..923d125 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -387,6 +387,11 @@
return mutex_lock_interruptible(&mddev->reconfig_mutex);
}
+static inline int mddev_is_locked(mddev_t *mddev)
+{
+ return mutex_is_locked(&mddev->reconfig_mutex);
+}
+
static inline int mddev_trylock(mddev_t * mddev)
{
return mutex_trylock(&mddev->reconfig_mutex);
@@ -2282,16 +2287,34 @@
return 1;
}
+static int strict_blocks_to_sectors(const char *buf, sector_t *sectors)
+{
+ unsigned long long blocks;
+ sector_t new;
+
+ if (strict_strtoull(buf, 10, &blocks) < 0)
+ return -EINVAL;
+
+ if (blocks & 1ULL << (8 * sizeof(blocks) - 1))
+ return -EINVAL; /* sector conversion overflow */
+
+ new = blocks * 2;
+ if (new != blocks * 2)
+ return -EINVAL; /* unsigned long long to sector_t overflow */
+
+ *sectors = new;
+ return 0;
+}
+
static ssize_t
rdev_size_store(mdk_rdev_t *rdev, const char *buf, size_t len)
{
mddev_t *my_mddev = rdev->mddev;
sector_t oldsectors = rdev->sectors;
- unsigned long long sectors;
+ sector_t sectors;
- if (strict_strtoull(buf, 10, §ors) < 0)
+ if (strict_blocks_to_sectors(buf, §ors) < 0)
return -EINVAL;
- sectors *= 2;
if (my_mddev->pers && rdev->raid_disk >= 0) {
if (my_mddev->persistent) {
sectors = super_types[my_mddev->major_version].
@@ -3182,12 +3205,11 @@
* not increase it (except from 0).
* If array is active, we can try an on-line resize
*/
- unsigned long long sectors;
- int err = strict_strtoull(buf, 10, §ors);
+ sector_t sectors;
+ int err = strict_blocks_to_sectors(buf, §ors);
if (err < 0)
return err;
- sectors *= 2;
if (mddev->pers) {
err = update_size(mddev, sectors);
md_update_sb(mddev, 1);
@@ -3627,6 +3649,57 @@
__ATTR(reshape_position, S_IRUGO|S_IWUSR, reshape_position_show,
reshape_position_store);
+static ssize_t
+array_size_show(mddev_t *mddev, char *page)
+{
+ if (mddev->external_size)
+ return sprintf(page, "%llu\n",
+ (unsigned long long)mddev->array_sectors/2);
+ else
+ return sprintf(page, "default\n");
+}
+
+static ssize_t
+array_size_store(mddev_t *mddev, const char *buf, size_t len)
+{
+ sector_t sectors;
+
+ if (strncmp(buf, "default", 7) == 0) {
+ if (mddev->pers)
+ sectors = mddev->pers->size(mddev, 0, 0);
+ else
+ sectors = mddev->array_sectors;
+
+ mddev->external_size = 0;
+ } else {
+ if (strict_blocks_to_sectors(buf, §ors) < 0)
+ return -EINVAL;
+ if (mddev->pers && mddev->pers->size(mddev, 0, 0) < sectors)
+ return -EINVAL;
+
+ mddev->external_size = 1;
+ }
+
+ mddev->array_sectors = sectors;
+ set_capacity(mddev->gendisk, mddev->array_sectors);
+ if (mddev->pers) {
+ struct block_device *bdev = bdget_disk(mddev->gendisk, 0);
+
+ if (bdev) {
+ mutex_lock(&bdev->bd_inode->i_mutex);
+ i_size_write(bdev->bd_inode,
+ (loff_t)mddev->array_sectors << 9);
+ mutex_unlock(&bdev->bd_inode->i_mutex);
+ bdput(bdev);
+ }
+ }
+
+ return len;
+}
+
+static struct md_sysfs_entry md_array_size =
+__ATTR(array_size, S_IRUGO|S_IWUSR, array_size_show,
+ array_size_store);
static struct attribute *md_default_attrs[] = {
&md_level.attr,
@@ -3640,6 +3713,7 @@
&md_safe_delay.attr,
&md_array_state.attr,
&md_reshape_position.attr,
+ &md_array_size.attr,
NULL,
};
@@ -4045,7 +4119,17 @@
err = mddev->pers->run(mddev);
if (err)
printk(KERN_ERR "md: pers->run() failed ...\n");
- else if (mddev->pers->sync_request) {
+ else if (mddev->pers->size(mddev, 0, 0) < mddev->array_sectors) {
+ WARN_ONCE(!mddev->external_size, "%s: default size too small,"
+ " but 'external_size' not in effect?\n", __func__);
+ printk(KERN_ERR
+ "md: invalid array_size %llu > default size %llu\n",
+ (unsigned long long)mddev->array_sectors / 2,
+ (unsigned long long)mddev->pers->size(mddev, 0, 0) / 2);
+ err = -EINVAL;
+ mddev->pers->stop(mddev);
+ }
+ if (err == 0 && mddev->pers->sync_request) {
err = bitmap_create(mddev);
if (err) {
printk(KERN_ERR "%s: failed to create bitmap (%d)\n",
@@ -4281,6 +4365,7 @@
export_array(mddev);
mddev->array_sectors = 0;
+ mddev->external_size = 0;
mddev->dev_sectors = 0;
mddev->raid_disks = 0;
mddev->recovery_cp = 0;
@@ -4979,10 +5064,23 @@
void md_set_array_sectors(mddev_t *mddev, sector_t array_sectors)
{
+ WARN(!mddev_is_locked(mddev), "%s: unlocked mddev!\n", __func__);
+
+ if (mddev->external_size)
+ return;
+
mddev->array_sectors = array_sectors;
}
EXPORT_SYMBOL(md_set_array_sectors);
+void md_set_array_sectors_lock(mddev_t *mddev, sector_t array_sectors)
+{
+ mddev_lock(mddev);
+ md_set_array_sectors(mddev, array_sectors);
+ mddev_unlock(mddev);
+}
+EXPORT_SYMBOL(md_set_array_sectors_lock);
+
static int update_size(mddev_t *mddev, sector_t num_sectors)
{
mdk_rdev_t *rdev;