Commit 940a2cd5 authored Jun 20, 2019 by Sam Eiderman Committed by Max Reitz Jun 24, 2019

vmdk: Fix comment regarding max l1_size coverage



Commit b0651b8c ("vmdk: Move l1_size check into vmdk_add_extent")
extended the l1_size check from VMDK4 to VMDK3 but did not update the
default coverage in the moved comment.

The previous vmdk4 calculation:

    (512 * 1024 * 1024) * 512(l2 entries) * 65536(grain) = 16PB

The added vmdk3 calculation:

    (512 * 1024 * 1024) * 4096(l2 entries) * 512(grain) = 1PB

Adding the calculation of vmdk3 to the comment.

In any case, VMware does not offer virtual disks more than 2TB for
vmdk4/vmdk3 or 64TB for the new undocumented seSparse format which is
not implemented yet in qemu.

Reviewed-by: Karl Heubaum <karl.heubaum@oracle.com>
Reviewed-by: Eyal Moscovici <eyal.moscovici@oracle.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Arbel Moshe <arbel.moshe@oracle.com>
Signed-off-by: Sam Eiderman <shmuel.eiderman@oracle.com>
Message-id: 20190620091057.47441-2-shmuel.eiderman@oracle.com
Reviewed-by: yuchenlin <yuchenlin@synology.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

parent 6ec889eb

block/vmdk.c

+8 −3

Original line number	Diff line number	Diff line
		@@ -426,10 +426,15 @@ static int vmdk_add_extent(BlockDriverState *bs,
		return -EFBIG;
		}
		if (l1_size > 512 * 1024 * 1024) {
		/* Although with big capacity and small l1_entry_sectors, we can get a
		/*
		* Although with big capacity and small l1_entry_sectors, we can get a
		* big l1_size, we don't want unbounded value to allocate the table.
		* Limit it to 512M, which is 16PB for default cluster and L2 table
		* size */
		* Limit it to 512M, which is:
		* 16PB - for default "Hosted Sparse Extent" (VMDK4)
		* cluster size: 64KB, L2 table size: 512 entries
		* 1PB - for default "ESXi Host Sparse Extent" (VMDK3/vmfsSparse)
		* cluster size: 512B, L2 table size: 4096 entries
		*/
		error_setg(errp, "L1 size too big");
		return -EFBIG;
		}