1 files changed, 105 insertions, 7 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 76ba69b31d6a..923d1250b9a9 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -387,6 +387,11 @@ static inline int mddev_lock(mddev_t * mddev)
         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 @@ static int overlaps(sector_t s1, sector_t l1, sector_t s2, sector_t l2)
         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, &sectors) < 0)
+        if (strict_blocks_to_sectors(buf, &sectors) < 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 @@ size_store(mddev_t *mddev, const char *buf, size_t len)
          * 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, &sectors);
+        sector_t sectors;
+        int err = strict_blocks_to_sectors(buf, &sectors);
 
         if (err < 0)
                 return err;
-        sectors *= 2;
         if (mddev->pers) {
                 err = update_size(mddev, sectors);
                 md_update_sb(mddev, 1);
@@ -3627,6 +3649,57 @@ static struct md_sysfs_entry md_reshape_position =
 __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, &sectors) < 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 @@ static struct attribute *md_default_attrs[] = {
         &md_safe_delay.attr,
         &md_array_state.attr,
         &md_reshape_position.attr,
+        &md_array_size.attr,
         NULL,
 };
 
@@ -4045,7 +4119,17 @@ static int do_md_run(mddev_t * mddev)
         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 @@ static int do_md_stop(mddev_t * mddev, int mode, int is_open)
                 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 @@ static int set_array_info(mddev_t * mddev, mdu_array_info_t *info)
 
 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;