From: Alberto Garcia <berto@igalia.com>
To: Eric Blake <eblake@redhat.com>, qemu-devel@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,
qemu-block@nongnu.org, Max Reitz <mreitz@redhat.com>
Subject: Re: [PATCH v5 07/31] qcow2: Document the Extended L2 Entries feature
Date: Wed, 06 May 2020 17:02:52 +0200 [thread overview]
Message-ID: <w51d07h9kdf.fsf@maestria.local.igalia.com> (raw)
In-Reply-To: <52c059ee-8a80-89af-dbab-ffea3976421e@redhat.com>
On Tue 05 May 2020 09:35:06 PM CEST, Eric Blake wrote:
> On 5/5/20 12:38 PM, Alberto Garcia wrote:
>> Subcluster allocation in qcow2 is implemented by extending the
>> existing L2 table entries and adding additional information to
>> indicate the allocation status of each subcluster.
>>
>> This patch documents the changes to the qcow2 format and how they
>> affect the calculation of the L2 cache size.
>>
>> Signed-off-by: Alberto Garcia <berto@igalia.com>
>> Reviewed-by: Max Reitz <mreitz@redhat.com>
>> ---
>> docs/interop/qcow2.txt | 68 ++++++++++++++++++++++++++++++++++++++++--
>> docs/qcow2-cache.txt | 19 +++++++++++-
>> 2 files changed, 83 insertions(+), 4 deletions(-)
>>
>
>> @@ -547,7 +557,8 @@ Standard Cluster Descriptor:
>> nor is data read from the backing file if the cluster is
>> unallocated.
>>
>> - With version 2, this is always 0.
>> + With version 2 or with extended L2 entries (see the next
>> + section), this is always 0.
>
> In your cover letter, you said you changed things to tolerate this bit
> being set even with extended L2 entries. Does this sentence need a
> tweak?
Not a bad idea.
>> +The last 64 bits contain a subcluster allocation bitmap with this format:
>> +
>> +Subcluster Allocation Bitmap (for standard clusters):
>> +
>> + Bit 0 - 31: Allocation status (one bit per subcluster)
>
> Why two spaces after '-'?
No reason, I guess I just didn't notice. I'll fix it.
Berto
next prev parent reply other threads:[~2020-05-06 15:03 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-05 17:38 [PATCH v5 00/31] Add subcluster allocation to qcow2 Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 01/31] qcow2: Make Qcow2AioTask store the full host offset Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 02/31] qcow2: Convert qcow2_get_cluster_offset() into qcow2_get_host_offset() Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 03/31] qcow2: Add calculate_l2_meta() Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 04/31] qcow2: Split cluster_needs_cow() out of count_cow_clusters() Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 05/31] qcow2: Process QCOW2_CLUSTER_ZERO_ALLOC clusters in handle_copied() Alberto Garcia
2020-05-05 19:23 ` Eric Blake
2020-05-05 17:38 ` [PATCH v5 06/31] qcow2: Add get_l2_entry() and set_l2_entry() Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 07/31] qcow2: Document the Extended L2 Entries feature Alberto Garcia
2020-05-05 19:35 ` Eric Blake
2020-05-06 15:02 ` Alberto Garcia [this message]
2020-05-06 15:24 ` Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 08/31] qcow2: Add dummy has_subclusters() function Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 09/31] qcow2: Add subcluster-related fields to BDRVQcow2State Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 10/31] qcow2: Add offset_to_sc_index() Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 11/31] qcow2: Add offset_into_subcluster() and size_to_subclusters() Alberto Garcia
2020-05-05 19:42 ` Eric Blake
2020-05-06 10:18 ` Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 12/31] qcow2: Add l2_entry_size() Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 13/31] qcow2: Update get/set_l2_entry() and add get/set_l2_bitmap() Alberto Garcia
2020-05-05 20:04 ` Eric Blake
2020-05-06 12:06 ` Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 14/31] qcow2: Add QCow2SubclusterType and qcow2_get_subcluster_type() Alberto Garcia
2020-05-05 21:08 ` Eric Blake
2020-05-05 17:38 ` [PATCH v5 15/31] qcow2: Add qcow2_cluster_is_allocated() Alberto Garcia
2020-05-05 21:10 ` Eric Blake
2020-05-05 17:38 ` [PATCH v5 16/31] qcow2: Add cluster type parameter to qcow2_get_host_offset() Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 17/31] qcow2: Replace QCOW2_CLUSTER_* with QCOW2_SUBCLUSTER_* Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 18/31] qcow2: Handle QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 19/31] qcow2: Add subcluster support to calculate_l2_meta() Alberto Garcia
2020-05-05 21:59 ` Eric Blake
2020-05-06 17:14 ` Alberto Garcia
2020-05-06 17:39 ` Eric Blake
2020-05-07 15:34 ` Alberto Garcia
2020-05-07 15:50 ` Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 20/31] qcow2: Add subcluster support to qcow2_get_host_offset() Alberto Garcia
2020-05-06 17:55 ` Eric Blake
2020-05-08 11:44 ` Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 21/31] qcow2: Add subcluster support to zero_in_l2_slice() Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 22/31] qcow2: Add subcluster support to discard_in_l2_slice() Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 23/31] qcow2: Add subcluster support to check_refcounts_l2() Alberto Garcia
2020-05-06 17:58 ` Eric Blake
2020-05-05 17:38 ` [PATCH v5 24/31] qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2() Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 25/31] qcow2: Clear the L2 bitmap when allocating a compressed cluster Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 26/31] qcow2: Add subcluster support to handle_alloc_space() Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 27/31] qcow2: Add subcluster support to qcow2_co_pwrite_zeroes() Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 28/31] qcow2: Add the 'extended_l2' option and the QCOW2_INCOMPAT_EXTL2 bit Alberto Garcia
2020-05-06 18:09 ` Eric Blake
2020-05-07 14:37 ` Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 29/31] qcow2: Assert that expand_zero_clusters_in_l1() does not support subclusters Alberto Garcia
2020-05-06 18:11 ` Eric Blake
2020-05-05 17:38 ` [PATCH v5 30/31] qcow2: Add subcluster support to qcow2_measure() Alberto Garcia
2020-05-06 18:13 ` Eric Blake
2020-05-07 15:16 ` Alberto Garcia
2020-05-05 17:38 ` [PATCH v5 31/31] iotests: Add tests for qcow2 images with extended L2 entries Alberto Garcia
2020-05-20 9:35 ` [PATCH v5 00/31] Add subcluster allocation to qcow2 Derek Su
2020-05-20 9:50 ` Alberto Garcia
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