[Qemu-devel] [PATCH v2 21/32] qcow2: Update handle_alloc() to support L2 slices

Alberto Garcia posted 32 patches 8 years, 1 month ago
There is a newer version of this series
[Qemu-devel] [PATCH v2 21/32] qcow2: Update handle_alloc() to support L2 slices
Posted by Alberto Garcia 8 years, 1 month ago
handle_alloc() loads an L2 table and limits the number of checked
clusters to the amount that fits inside that table. Since we'll be
loading L2 slices instead of full tables we need to update that limit.

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 <berto@igalia.com>
---
 block/qcow2-cluster.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 09b6dc984f..0d126581bd 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1283,7 +1283,7 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,
 {
     BDRVQcow2State *s = bs->opaque;
     int l2_index;
-    uint64_t *l2_table;
+    uint64_t *l2_slice;
     uint64_t entry;
     uint64_t nb_clusters;
     int ret;
@@ -1296,29 +1296,29 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,
     assert(*bytes > 0);
 
     /*
-     * Calculate the number of clusters to look for. We stop at L2 table
+     * Calculate the number of clusters to look for. We stop at L2 slice
      * boundaries to keep things simple.
      */
     nb_clusters =
         size_to_clusters(s, offset_into_cluster(s, guest_offset) + *bytes);
 
-    l2_index = offset_to_l2_index(s, guest_offset);
-    nb_clusters = MIN(nb_clusters, s->l2_size - l2_index);
+    l2_index = offset_to_l2_slice_index(s, guest_offset);
+    nb_clusters = MIN(nb_clusters, s->l2_slice_size - l2_index);
     assert(nb_clusters <= INT_MAX);
 
     /* Find L2 entry for the first involved cluster */
-    ret = get_cluster_table(bs, guest_offset, &l2_table, &l2_index);
+    ret = get_cluster_table(bs, guest_offset, &l2_slice, &l2_index);
     if (ret < 0) {
         return ret;
     }
 
-    entry = be64_to_cpu(l2_table[l2_index]);
+    entry = be64_to_cpu(l2_slice[l2_index]);
 
     /* For the moment, overwrite compressed clusters one by one */
     if (entry & QCOW_OFLAG_COMPRESSED) {
         nb_clusters = 1;
     } else {
-        nb_clusters = count_cow_clusters(s, nb_clusters, l2_table, l2_index);
+        nb_clusters = count_cow_clusters(s, nb_clusters, l2_slice, l2_index);
     }
 
     /* This function is only called when there were no non-COW clusters, so if
@@ -1347,7 +1347,7 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,
          * nb_clusters already to a range of COW clusters */
         preallocated_nb_clusters =
             count_contiguous_clusters(nb_clusters, s->cluster_size,
-                                      &l2_table[l2_index], QCOW_OFLAG_COPIED);
+                                      &l2_slice[l2_index], QCOW_OFLAG_COPIED);
         assert(preallocated_nb_clusters > 0);
 
         nb_clusters = preallocated_nb_clusters;
@@ -1358,7 +1358,7 @@ static int handle_alloc(BlockDriverState *bs, uint64_t guest_offset,
         keep_old_clusters = true;
     }
 
-    qcow2_cache_put(s->l2_table_cache, (void **) &l2_table);
+    qcow2_cache_put(s->l2_table_cache, (void **) &l2_slice);
 
     if (!alloc_cluster_offset) {
         /* Allocate, if necessary at a given offset in the image file */
-- 
2.11.0


Re: [Qemu-devel] [PATCH v2 21/32] qcow2: Update handle_alloc() to support L2 slices
Posted by Eric Blake 8 years ago
On 12/15/2017 06:53 AM, Alberto Garcia wrote:
> handle_alloc() loads an L2 table and limits the number of checked
> clusters to the amount that fits inside that table. Since we'll be
> loading L2 slices instead of full tables we need to update that limit.
> 
> 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 <berto@igalia.com>
> ---
>  block/qcow2-cluster.c | 18 +++++++++---------
>  1 file changed, 9 insertions(+), 9 deletions(-)
> 
Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org