virtio_blk: fix incorrect message when disk is resized

The message printed on disk resize is incorrect.  The following is
printed when resizing to 2 GiB:

  $ truncate -s 1G test.img
  $ qemu -device virtio-blk-pci,logical_block_size=4096,...
  (qemu) block_resize drive1 2G

  virtio_blk virtio0: new size: 4194304 4096-byte logical blocks (17.2 GB/16.0 GiB)

The virtio_blk capacity config field is in 512-byte sector units
regardless of logical_block_size as per the VIRTIO specification.
Therefore the message should read:

  virtio_blk virtio0: new size: 524288 4096-byte logical blocks (2.15 GB/2.0 GiB)

Note that this only affects the printed message.  Thankfully the actual
block device has the correct size because the block layer expects
capacity in sectors.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 1498b899a593e31951c835f4f537d1bb03d0e596..d3d5523862c227d86166a56fba230467b9b545fc 100644 (file)
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -381,6 +381,7 @@ static void virtblk_config_changed_work(struct work_struct *work)
        struct request_queue *q = vblk->disk->queue;
        char cap_str_2[10], cap_str_10[10];
        char *envp[] = { "RESIZE=1", NULL };
+       unsigned long long nblocks;
        u64 capacity;
 
        /* Host must always specify the capacity. */
@@ -393,16 +394,19 @@ static void virtblk_config_changed_work(struct work_struct *work)
                capacity = (sector_t)-1;
        }
 
-       string_get_size(capacity, queue_logical_block_size(q),
+       nblocks = DIV_ROUND_UP_ULL(capacity, queue_logical_block_size(q) >> 9);
+
+       string_get_size(nblocks, queue_logical_block_size(q),
                        STRING_UNITS_2, cap_str_2, sizeof(cap_str_2));
-       string_get_size(capacity, queue_logical_block_size(q),
+       string_get_size(nblocks, queue_logical_block_size(q),
                        STRING_UNITS_10, cap_str_10, sizeof(cap_str_10));
 
        dev_notice(&vdev->dev,
-                 "new size: %llu %d-byte logical blocks (%s/%s)\n",
-                 (unsigned long long)capacity,
-                 queue_logical_block_size(q),
-                 cap_str_10, cap_str_2);
+                  "new size: %llu %d-byte logical blocks (%s/%s)\n",
+                  nblocks,
+                  queue_logical_block_size(q),
+                  cap_str_10,
+                  cap_str_2);
 
        set_capacity(vblk->disk, capacity);
        revalidate_disk(vblk->disk);