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[Qemu-block] [PATCH 18/31] qcow2: Update qcow2_get_cluster_offset() to s
From: |
Alberto Garcia |
Subject: |
[Qemu-block] [PATCH 18/31] qcow2: Update qcow2_get_cluster_offset() to support L2 slices |
Date: |
Thu, 12 Oct 2017 16:05:32 +0300 |
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 | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 580fb50869..860e56ec7c 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -522,8 +522,8 @@ 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;
@@ -532,12 +532,11 @@ 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 = (s->l2_slice_size - offset_to_l2_slice_index(s, offset))
+ << s->cluster_bits;
if (bytes_needed > bytes_available) {
bytes_needed = bytes_available;
@@ -566,17 +565,17 @@ 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
@@ -603,14 +602,14 @@ 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,
@@ -626,7 +625,7 @@ 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;
@@ -644,7 +643,7 @@ 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-block] [PATCH 30/31] qcow2: Rename l2_table in count_cow_clusters(), (continued)
- [Qemu-block] [PATCH 30/31] qcow2: Rename l2_table in count_cow_clusters(), Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 26/31] qcow2: Update qcow2_truncate() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 29/31] qcow2: Rename l2_table in count_contiguous_clusters_unallocated(), Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 25/31] qcow2: Update expand_zero_clusters_in_l1() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 24/31] qcow2: Update qcow2_update_snapshot_refcount() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 23/31] qcow2: Update zero_single_l2() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 22/31] qcow2: Update discard_single_l2() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 21/31] qcow2: Update handle_alloc() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 19/31] qcow2: Update qcow2_alloc_cluster_link_l2() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 20/31] qcow2: Update handle_copied() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 18/31] qcow2: Update qcow2_get_cluster_offset() to support L2 slices,
Alberto Garcia <=
- [Qemu-block] [PATCH 08/31] qcow2: Remove BDS parameter from qcow2_cache_destroy(), Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 10/31] qcow2: Remove BDS parameter from qcow2_cache_discard(), Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 12/31] qcow2: Add offset_to_l1_index(), Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 07/31] qcow2: Remove BDS parameter from qcow2_cache_put(), Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 16/31] qcow2: Update l2_allocate() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 11/31] qcow2: Remove BDS parameter from qcow2_cache_is_table_offset(), Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 06/31] qcow2: Remove BDS parameter from qcow2_cache_entry_mark_dirty(), Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 15/31] qcow2: Update l2_load() to support L2 slices, Alberto Garcia, 2017/10/12
- [Qemu-block] [PATCH 05/31] qcow2: Remove BDS parameter from qcow2_cache_table_release(), Alberto Garcia, 2017/10/12