Commit e28626a0 authored Apr 26, 2013 by Alex Elder Committed by Sage Weil May 01, 2013

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>

parent 2e9f7f1c

drivers/block/rbd.c

+8 −6

Original line number	Diff line number	Diff line
		@@ -3034,16 +3034,18 @@ static void rbd_remove_all_snaps(struct rbd_device *rbd_dev)

		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;
		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);
		rbd_dev->mapping.size = (u64) size;
		set_capacity(rbd_dev->disk, size);
		}
		}

		/*
		* only read the first part of the ondisk header, without the snaps info