rbd: fix a bug in resizing a mapping
When a snapshot context update occurs, rbd_update_mapping_size() is
called to set the capacity of the disk to record the updated
size of the image in case it has changed.
There's a bug though. The mapping size is in units of *bytes*. The
code that updates the mapping size field is assigning a value that
has been scaled down to *sectors*.
Fix that. Also, check to see if the size has actually changed, and
don't bother updating things (specifically, calling set_capacity())
if it has not.
This resolves:
http://tracker.ceph.com/issues/4833
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 3bd12ea..83265ad 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3034,15 +3034,17 @@
static void rbd_update_mapping_size(struct rbd_device *rbd_dev)
{
- sector_t size;
-
if (rbd_dev->spec->snap_id != CEPH_NOSNAP)
return;
- size = (sector_t) rbd_dev->header.image_size / SECTOR_SIZE;
- dout("setting size to %llu sectors", (unsigned long long) size);
- rbd_dev->mapping.size = (u64) size;
- set_capacity(rbd_dev->disk, size);
+ if (rbd_dev->mapping.size != rbd_dev->header.image_size) {
+ sector_t size;
+
+ rbd_dev->mapping.size = rbd_dev->header.image_size;
+ size = (sector_t)rbd_dev->mapping.size / SECTOR_SIZE;
+ dout("setting size to %llu sectors", (unsigned long long)size);
+ set_capacity(rbd_dev->disk, size);
+ }
}
/*