Re: [Qemu-devel] [PATCH v3 21/39] qcow2: Update qcow2_alloc_cluster_link_l2() to support L2 slices

[Alberto Garcia]

On Thu 01 Feb 2018 07:44:56 PM CET, Max Reitz  wrote:
> On 2018-01-26 15:59, Alberto Garcia wrote:
>> There's a loop in this function that iterates over the L2 entries in a
>> table, so now we need to assert that it remains within the limits of
>> an L2 slice.
>> 
>> Apart from that, this function doesn't need any additional changes, so
>> this patch simply updates the variable name from l2_table to l2_slice.
>> 
>> Signed-off-by: Alberto Garcia 
>> Reviewed-by: Eric Blake 
>> ---
>>  block/qcow2-cluster.c | 16 
>>  1 file changed, 8 insertions(+), 8 deletions(-)
>
> Hm, well, strictly speaking this patch should not be at this point in
> this series -- e.g. handle_alloc() so far only limits its nb_clusters to
> the L2 size, not the L2 slice size.

Yeah, I didn't try to be too strict with this because you can only
change the slice size after everything else is ready.

Berto

Re: [Qemu-devel] [PATCH v3 21/39] qcow2: Update qcow2_alloc_cluster_link_l2() to support L2 slices

[Max Reitz]

On 2018-01-26 15:59, Alberto Garcia wrote:
> There's a loop in this function that iterates over the L2 entries in a
> table, so now we need to assert that it remains within the limits of
> an L2 slice.
> 
> Apart from that, this function doesn't need any additional changes, so
> this patch simply updates the variable name from l2_table to l2_slice.
> 
> Signed-off-by: Alberto Garcia 
> Reviewed-by: Eric Blake 
> ---
>  block/qcow2-cluster.c | 16 
>  1 file changed, 8 insertions(+), 8 deletions(-)

Hm, well, strictly speaking this patch should not be at this point in
this series -- e.g. handle_alloc() so far only limits its nb_clusters to
the L2 size, not the L2 slice size.

But that's nit picking because the slice size equals the L2 size anyway
(for now), so

Reviewed-by: Max Reitz 



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[Qemu-devel] [PATCH v3 21/39] qcow2: Update qcow2_alloc_cluster_link_l2() to support L2 slices

[Alberto Garcia]

There's a loop in this function that iterates over the L2 entries in a
table, so now we need to assert that it remains within the limits of
an L2 slice.

Apart from that, this function doesn't need any additional changes, so
this patch simply updates the variable name from l2_table to l2_slice.

Signed-off-by: Alberto Garcia 
Reviewed-by: Eric Blake 
---
 block/qcow2-cluster.c | 16 
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 128a82dc5a..abc9e3ed6a 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -923,7 +923,7 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, 
QCowL2Meta *m)
 {
 BDRVQcow2State *s = bs->opaque;
 int i, j = 0, l2_index, ret;
-uint64_t *old_cluster, *l2_table;
+uint64_t *old_cluster, *l2_slice;
 uint64_t cluster_offset = m->alloc_offset;
 
 trace_qcow2_cluster_link_l2(qemu_coroutine_self(), m->nb_clusters);
@@ -950,13 +950,13 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, 
QCowL2Meta *m)
s->refcount_block_cache);
 }
 
-ret = get_cluster_table(bs, m->offset, _table, _index);
+ret = get_cluster_table(bs, m->offset, _slice, _index);
 if (ret < 0) {
 goto err;
 }
-qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_table);
+qcow2_cache_entry_mark_dirty(s->l2_table_cache, l2_slice);
 
-assert(l2_index + m->nb_clusters <= s->l2_size);
+assert(l2_index + m->nb_clusters <= s->l2_slice_size);
 for (i = 0; i < m->nb_clusters; i++) {
 /* if two concurrent writes happen to the same unallocated cluster
  * each write allocates separate cluster and writes data concurrently.
@@ -964,16 +964,16 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, 
QCowL2Meta *m)
  * cluster the second one has to do RMW (which is done above by
  * perform_cow()), update l2 table with its cluster pointer and free
  * old cluster. This is what this loop does */
-if (l2_table[l2_index + i] != 0) {
-old_cluster[j++] = l2_table[l2_index + i];
+if (l2_slice[l2_index + i] != 0) {
+old_cluster[j++] = l2_slice[l2_index + i];
 }
 
-l2_table[l2_index + i] = cpu_to_be64((cluster_offset +
+l2_slice[l2_index + i] = cpu_to_be64((cluster_offset +
 (i << s->cluster_bits)) | QCOW_OFLAG_COPIED);
  }
 
 
-qcow2_cache_put(s->l2_table_cache, (void **) _table);
+qcow2_cache_put(s->l2_table_cache, (void **) _slice);
 
 /*
  * If this was a COW, we need to decrease the refcount of the old cluster.
-- 
2.11.0