From: Alberto Garcia <berto@igalia.com>
To: qemu-devel@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,
Alberto Garcia <berto@igalia.com>,
qemu-block@nongnu.org, Derek Su <dereksu@qnap.com>,
Max Reitz <mreitz@redhat.com>
Subject: [PATCH v6 15/32] qcow2: Add qcow2_get_subcluster_range_type()
Date: Sun, 24 May 2020 16:51:35 +0200 [thread overview]
Message-ID: <1a2ca24ad22d0c14d1c6cb05f5ab4db7444a7161.1590331741.git.berto@igalia.com> (raw)
In-Reply-To: <cover.1590331741.git.berto@igalia.com>
There are situations in which we want to know how many contiguous
subclusters of the same type there are in a given cluster. This can be
done by simply iterating over the subclusters and repeatedly calling
qcow2_get_subcluster_type() for each one of them.
However once we determined the type of a subcluster we can check the
rest efficiently by counting the number of adjacent ones (or zeroes)
in the bitmap. This is what this function does.
Signed-off-by: Alberto Garcia <berto@igalia.com>
---
block/qcow2-cluster.c | 51 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 51 insertions(+)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 8b2fc550b7..32dc6e75e3 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -375,6 +375,57 @@ fail:
return ret;
}
+/*
+ * For a given L2 entry, count the number of contiguous subclusters of
+ * the same type starting from @sc_from. Compressed clusters are
+ * treated as if they were divided into subclusters of size
+ * s->subcluster_size.
+ *
+ * Return the number of contiguous subclusters and set @type to the
+ * subcluster type.
+ *
+ * If the L2 entry is invalid return -errno and set @type to
+ * QCOW2_SUBCLUSTER_INVALID.
+ */
+G_GNUC_UNUSED
+static int qcow2_get_subcluster_range_type(BlockDriverState *bs,
+ uint64_t l2_entry,
+ uint64_t l2_bitmap,
+ unsigned sc_from,
+ QCow2SubclusterType *type)
+{
+ BDRVQcow2State *s = bs->opaque;
+ uint32_t val;
+
+ *type = qcow2_get_subcluster_type(bs, l2_entry, l2_bitmap, sc_from);
+
+ if (*type == QCOW2_SUBCLUSTER_INVALID) {
+ return -EINVAL;
+ } else if (!has_subclusters(s) || *type == QCOW2_SUBCLUSTER_COMPRESSED) {
+ return s->subclusters_per_cluster - sc_from;
+ }
+
+ switch (*type) {
+ case QCOW2_SUBCLUSTER_NORMAL:
+ val = l2_bitmap | QCOW_OFLAG_SUB_ALLOC_RANGE(0, sc_from);
+ return cto32(val) - sc_from;
+
+ case QCOW2_SUBCLUSTER_ZERO_PLAIN:
+ case QCOW2_SUBCLUSTER_ZERO_ALLOC:
+ val = (l2_bitmap | QCOW_OFLAG_SUB_ZERO_RANGE(0, sc_from)) >> 32;
+ return cto32(val) - sc_from;
+
+ case QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN:
+ case QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC:
+ val = ((l2_bitmap >> 32) | l2_bitmap)
+ & ~QCOW_OFLAG_SUB_ALLOC_RANGE(0, sc_from);
+ return ctz32(val) - sc_from;
+
+ default:
+ g_assert_not_reached();
+ }
+}
+
/*
* Checks how many clusters in a given L2 slice are contiguous in the image
* file. As soon as one of the flags in the bitmask stop_flags changes compared
--
2.20.1
next prev parent reply other threads:[~2020-05-24 15:08 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-24 14:51 [PATCH v6 00/32] Add subcluster allocation to qcow2 Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 01/32] qcow2: Make Qcow2AioTask store the full host offset Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 02/32] qcow2: Convert qcow2_get_cluster_offset() into qcow2_get_host_offset() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 03/32] qcow2: Add calculate_l2_meta() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 04/32] qcow2: Split cluster_needs_cow() out of count_cow_clusters() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 05/32] qcow2: Process QCOW2_CLUSTER_ZERO_ALLOC clusters in handle_copied() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 06/32] qcow2: Add get_l2_entry() and set_l2_entry() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 07/32] qcow2: Document the Extended L2 Entries feature Alberto Garcia
2020-05-26 19:54 ` Eric Blake
2020-05-24 14:51 ` [PATCH v6 08/32] qcow2: Add dummy has_subclusters() function Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 09/32] qcow2: Add subcluster-related fields to BDRVQcow2State Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 10/32] qcow2: Add offset_to_sc_index() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 11/32] qcow2: Add offset_into_subcluster() and size_to_subclusters() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 12/32] qcow2: Add l2_entry_size() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 13/32] qcow2: Update get/set_l2_entry() and add get/set_l2_bitmap() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 14/32] qcow2: Add QCow2SubclusterType and qcow2_get_subcluster_type() Alberto Garcia
2020-05-24 14:51 ` Alberto Garcia [this message]
2020-05-24 14:51 ` [PATCH v6 16/32] qcow2: Add qcow2_cluster_is_allocated() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 17/32] qcow2: Add cluster type parameter to qcow2_get_host_offset() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 18/32] qcow2: Replace QCOW2_CLUSTER_* with QCOW2_SUBCLUSTER_* Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 19/32] qcow2: Handle QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 20/32] qcow2: Add subcluster support to calculate_l2_meta() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 21/32] qcow2: Add subcluster support to qcow2_get_host_offset() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 22/32] qcow2: Add subcluster support to zero_in_l2_slice() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 23/32] qcow2: Add subcluster support to discard_in_l2_slice() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 24/32] qcow2: Add subcluster support to check_refcounts_l2() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 25/32] qcow2: Update L2 bitmap in qcow2_alloc_cluster_link_l2() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 26/32] qcow2: Clear the L2 bitmap when allocating a compressed cluster Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 27/32] qcow2: Add subcluster support to handle_alloc_space() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 28/32] qcow2: Add subcluster support to qcow2_co_pwrite_zeroes() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 29/32] qcow2: Add subcluster support to qcow2_measure() Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 30/32] qcow2: Add the 'extended_l2' option and the QCOW2_INCOMPAT_EXTL2 bit Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 31/32] qcow2: Assert that expand_zero_clusters_in_l1() does not support subclusters Alberto Garcia
2020-05-24 14:51 ` [PATCH v6 32/32] iotests: Add tests for qcow2 images with extended L2 entries Alberto Garcia
2020-05-24 16:29 ` [PATCH v6 00/32] Add subcluster allocation to qcow2 no-reply
2020-05-24 16:34 ` no-reply
2020-05-25 16:06 ` Alberto Garcia
2020-05-24 16:42 ` no-reply
2020-05-24 16:46 ` no-reply
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