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[RFC PATCH v3 07/27] qcow2: Add subcluster-related fields to BDRVQcow2St
From: |
Alberto Garcia |
Subject: |
[RFC PATCH v3 07/27] qcow2: Add subcluster-related fields to BDRVQcow2State |
Date: |
Sun, 22 Dec 2019 12:36:48 +0100 |
This patch adds the following new fields to BDRVQcow2State:
- subclusters_per_cluster: Number of subclusters in a cluster
- subcluster_size: The size of each subcluster, in bytes
- subcluster_bits: No. of bits so 1 << subcluster_bits = subcluster_size
Images without subclusters are treated as if they had exactly one,
with subcluster_size = cluster_size.
Signed-off-by: Alberto Garcia <address@hidden>
---
block/qcow2.c | 5 +++++
block/qcow2.h | 5 +++++
2 files changed, 10 insertions(+)
diff --git a/block/qcow2.c b/block/qcow2.c
index 3866b47946..cbd857e9c7 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1378,6 +1378,11 @@ static int coroutine_fn qcow2_do_open(BlockDriverState
*bs, QDict *options,
}
}
+ s->subclusters_per_cluster =
+ has_subclusters(s) ? QCOW_MAX_SUBCLUSTERS_PER_CLUSTER : 1;
+ s->subcluster_size = s->cluster_size / s->subclusters_per_cluster;
+ s->subcluster_bits = ctz32(s->subcluster_size);
+
/* Check support for various header values */
if (header.refcount_order > 6) {
error_setg(errp, "Reference count entry width too large; may not "
diff --git a/block/qcow2.h b/block/qcow2.h
index 1db3fc5dbc..941330cfc9 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -78,6 +78,8 @@
/* The cluster reads as all zeros */
#define QCOW_OFLAG_ZERO (1ULL << 0)
+#define QCOW_MAX_SUBCLUSTERS_PER_CLUSTER 32
+
#define MIN_CLUSTER_BITS 9
#define MAX_CLUSTER_BITS 21
@@ -284,6 +286,9 @@ typedef struct BDRVQcow2State {
int cluster_bits;
int cluster_size;
int l2_slice_size;
+ int subcluster_bits;
+ int subcluster_size;
+ int subclusters_per_cluster;
int l2_bits;
int l2_size;
int l1_size;
--
2.20.1
- [RFC PATCH v3 00/27] Add subcluster allocation to qcow2, Alberto Garcia, 2019/12/22
- [RFC PATCH v3 16/27] qcow2: Add subcluster support to zero_in_l2_slice(), Alberto Garcia, 2019/12/22
- [RFC PATCH v3 07/27] qcow2: Add subcluster-related fields to BDRVQcow2State,
Alberto Garcia <=
- [RFC PATCH v3 18/27] qcow2: Add subcluster support to check_refcounts_l2(), Alberto Garcia, 2019/12/22
- [RFC PATCH v3 17/27] qcow2: Add subcluster support to discard_in_l2_slice(), Alberto Garcia, 2019/12/22
- [RFC PATCH v3 10/27] qcow2: Update get/set_l2_entry() and add get/set_l2_bitmap(), Alberto Garcia, 2019/12/22
- [RFC PATCH v3 01/27] qcow2: Add calculate_l2_meta(), Alberto Garcia, 2019/12/22
- [RFC PATCH v3 24/27] qcow2: Restrict qcow2_co_pwrite_zeroes() to full clusters only, Alberto Garcia, 2019/12/22
- [RFC PATCH v3 11/27] qcow2: Add QCow2SubclusterType and qcow2_get_subcluster_type(), Alberto Garcia, 2019/12/22
- [RFC PATCH v3 03/27] qcow2: Process QCOW2_CLUSTER_ZERO_ALLOC clusters in handle_copied(), Alberto Garcia, 2019/12/22
- [RFC PATCH v3 27/27] iotests: Add tests for qcow2 images with extended L2 entries, Alberto Garcia, 2019/12/22
- [RFC PATCH v3 21/27] qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2(), Alberto Garcia, 2019/12/22
- [RFC PATCH v3 13/27] qcow2: Handle QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC, Alberto Garcia, 2019/12/22