Re: [Qemu-devel] [PATCH v5 01/11] qcow2: Calculate refcount block entry count

[Kevin Wolf <kwolf@redhat.com>]

Am 20.10.2014 um 16:39 hat Max Reitz geschrieben:
> On 20.10.2014 at 16:25, Kevin Wolf wrote:
> >Am 29.08.2014 um 23:40 hat Max Reitz geschrieben:
> >>The size of a refblock entry is (in theory) variable; calculate
> >>therefore the number of entries per refblock and the according bit shift
> >>(1 << x == entry count) when opening an image.
> >>
> >>Signed-off-by: Max Reitz <mreitz@redhat.com>
> >>---
> >>  block/qcow2.c | 2 ++
> >>  block/qcow2.h | 2 ++
> >>  2 files changed, 4 insertions(+)
> >>
> >>diff --git a/block/qcow2.c b/block/qcow2.c
> >>index f9e045f..172ad00 100644
> >>--- a/block/qcow2.c
> >>+++ b/block/qcow2.c
> >>@@ -689,6 +689,8 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
> >>      s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */
> >>      s->l2_size = 1 << s->l2_bits;
> >>+    s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3);
> >>+    s->refcount_block_size = 1 << s->refcount_block_bits;
> >>      bs->total_sectors = header.size / 512;
> >>      s->csize_shift = (62 - (s->cluster_bits - 8));
> >>      s->csize_mask = (1 << (s->cluster_bits - 8)) - 1;
> >>diff --git a/block/qcow2.h b/block/qcow2.h
> >>index 6aeb7ea..7c01fb7 100644
> >>--- a/block/qcow2.h
> >>+++ b/block/qcow2.h
> >>@@ -222,6 +222,8 @@ typedef struct BDRVQcowState {
> >>      int l2_size;
> >>      int l1_size;
> >>      int l1_vm_state_index;
> >>+    int refcount_block_bits;
> >>+    int refcount_block_size;
> >Might just be me, but size sounds to me as if the unit were bytes. Would
> >you mind renaming this as refcount_block_entries or refblock_entries?
> 
> If I'm doing a v7, no. Otherwise, well, see l1_size and l2_size. ;-)

Good point. This has confused people more than once, so it's probably
not just me.

Kevin