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[Qemu-devel] [PATCH v2 18/32] qcow2: Update qcow2_get_cluster_offset() t
From: |
Alberto Garcia |
Subject: |
[Qemu-devel] [PATCH v2 18/32] qcow2: Update qcow2_get_cluster_offset() to support L2 slices |
Date: |
Fri, 15 Dec 2017 13:53:46 +0100 |
qcow2_get_cluster_offset() checks how many contiguous bytes are
available at a given offset. The returned number of bytes is limited
by the amount that can be addressed without having to load more than
one L2 table.
Since we'll be loading L2 slices instead of full tables this patch
changes the limit accordingly using the size of the L2 slice for the
calculations instead of the full table size.
The l2_table variable is also renamed to l2_slice to reflect this, and
offset_to_l2_index() is replaced with offset_to_l2_slice_index().
Signed-off-by: Alberto Garcia <address@hidden>
---
block/qcow2-cluster.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 3d43dc2307..f167bb6336 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -530,8 +530,8 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t
offset,
{
BDRVQcow2State *s = bs->opaque;
unsigned int l2_index;
- uint64_t l1_index, l2_offset, *l2_table;
- int l1_bits, c;
+ uint64_t l1_index, l2_offset, *l2_slice;
+ int c;
unsigned int offset_in_cluster;
uint64_t bytes_available, bytes_needed, nb_clusters;
QCow2ClusterType type;
@@ -540,12 +540,12 @@ int qcow2_get_cluster_offset(BlockDriverState *bs,
uint64_t offset,
offset_in_cluster = offset_into_cluster(s, offset);
bytes_needed = (uint64_t) *bytes + offset_in_cluster;
- l1_bits = s->l2_bits + s->cluster_bits;
-
/* compute how many bytes there are between the start of the cluster
- * containing offset and the end of the l1 entry */
- bytes_available = (1ULL << l1_bits) - (offset & ((1ULL << l1_bits) - 1))
- + offset_in_cluster;
+ * containing offset and the end of the l2 slice that contains
+ * the entry pointing to it */
+ bytes_available =
+ ((uint64_t) (s->l2_slice_size - offset_to_l2_slice_index(s, offset)))
+ << s->cluster_bits;
if (bytes_needed > bytes_available) {
bytes_needed = bytes_available;
@@ -574,17 +574,17 @@ int qcow2_get_cluster_offset(BlockDriverState *bs,
uint64_t offset,
return -EIO;
}
- /* load the l2 table in memory */
+ /* load the l2 slice in memory */
- ret = l2_load(bs, offset, l2_offset, &l2_table);
+ ret = l2_load(bs, offset, l2_offset, &l2_slice);
if (ret < 0) {
return ret;
}
/* find the cluster offset for the given disk offset */
- l2_index = offset_to_l2_index(s, offset);
- *cluster_offset = be64_to_cpu(l2_table[l2_index]);
+ l2_index = offset_to_l2_slice_index(s, offset);
+ *cluster_offset = be64_to_cpu(l2_slice[l2_index]);
nb_clusters = size_to_clusters(s, bytes_needed);
/* bytes_needed <= *bytes + offset_in_cluster, both of which are unsigned
@@ -611,14 +611,14 @@ int qcow2_get_cluster_offset(BlockDriverState *bs,
uint64_t offset,
case QCOW2_CLUSTER_UNALLOCATED:
/* how many empty clusters ? */
c = count_contiguous_clusters_unallocated(nb_clusters,
- &l2_table[l2_index], type);
+ &l2_slice[l2_index], type);
*cluster_offset = 0;
break;
case QCOW2_CLUSTER_ZERO_ALLOC:
case QCOW2_CLUSTER_NORMAL:
/* how many allocated clusters ? */
c = count_contiguous_clusters(nb_clusters, s->cluster_size,
- &l2_table[l2_index], QCOW_OFLAG_ZERO);
+ &l2_slice[l2_index], QCOW_OFLAG_ZERO);
*cluster_offset &= L2E_OFFSET_MASK;
if (offset_into_cluster(s, *cluster_offset)) {
qcow2_signal_corruption(bs, true, -1, -1,
@@ -634,7 +634,7 @@ int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t
offset,
abort();
}
- qcow2_cache_put(s->l2_table_cache, (void **) &l2_table);
+ qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
bytes_available = (int64_t)c * s->cluster_size;
@@ -652,7 +652,7 @@ out:
return type;
fail:
- qcow2_cache_put(s->l2_table_cache, (void **)&l2_table);
+ qcow2_cache_put(s->l2_table_cache, (void **)&l2_slice);
return ret;
}
--
2.11.0
- [Qemu-devel] [PATCH v2 09/32] qcow2: Remove BDS parameter from qcow2_cache_clean_unused(), (continued)
- [Qemu-devel] [PATCH v2 09/32] qcow2: Remove BDS parameter from qcow2_cache_clean_unused(), Alberto Garcia, 2017/12/15
- [Qemu-devel] [PATCH v2 27/32] qcow2: Rename l2_table in qcow2_alloc_compressed_cluster_offset(), Alberto Garcia, 2017/12/15
- [Qemu-devel] [PATCH v2 17/32] qcow2: Update get_cluster_table() to support L2 slices, Alberto Garcia, 2017/12/15
- [Qemu-devel] [PATCH v2 04/32] qcow2: Remove BDS parameter from qcow2_cache_get_table_idx(), Alberto Garcia, 2017/12/15
- [Qemu-devel] [PATCH v2 32/32] iotests: Add test for l2-cache-entry-size, Alberto Garcia, 2017/12/15
- [Qemu-devel] [PATCH v2 24/32] qcow2: Update qcow2_update_snapshot_refcount() to support L2 slices, Alberto Garcia, 2017/12/15
- [Qemu-devel] [PATCH v2 31/32] qcow2: Allow configuring the L2 slice size, Alberto Garcia, 2017/12/15
- [Qemu-devel] [PATCH v2 07/32] qcow2: Remove BDS parameter from qcow2_cache_put(), Alberto Garcia, 2017/12/15
- [Qemu-devel] [PATCH v2 25/32] qcow2: Update expand_zero_clusters_in_l1() to support L2 slices, Alberto Garcia, 2017/12/15
- [Qemu-devel] [PATCH v2 10/32] qcow2: Remove BDS parameter from qcow2_cache_discard(), Alberto Garcia, 2017/12/15
- [Qemu-devel] [PATCH v2 18/32] qcow2: Update qcow2_get_cluster_offset() to support L2 slices,
Alberto Garcia <=
- [Qemu-devel] [PATCH v2 20/32] qcow2: Update handle_copied() to support L2 slices, Alberto Garcia, 2017/12/15
- [Qemu-devel] [PATCH v2 16/32] qcow2: Update l2_allocate() to support L2 slices, Alberto Garcia, 2017/12/15
- [Qemu-devel] [PATCH v2 19/32] qcow2: Update qcow2_alloc_cluster_link_l2() to support L2 slices, Alberto Garcia, 2017/12/15
- [Qemu-devel] [PATCH v2 12/32] qcow2: Add offset_to_l1_index(), Alberto Garcia, 2017/12/15
- Re: [Qemu-devel] [PATCH v2 00/32] Allow configuring the qcow2 L2 cache entry size, no-reply, 2017/12/15
- Re: [Qemu-devel] [PATCH v2 00/32] Allow configuring the qcow2 L2 cache entry size, no-reply, 2017/12/15