[Qemu-devel] [RFC PATCH 05/16] qcow2: Ignore reserved bits in L1/L2 entries

[Kevin Wolf <kwolf@redhat.com>]

This changes the still existing places that assume that the only flags
are QCOW_OFLAG_COPIED and QCOW_OFLAG_COMPRESSED to properly mask out
reserved bits.

It does not convert bdrv_check yet.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/qcow2-cluster.c  |   26 +++++++++++++-------------
 block/qcow2-refcount.c |   12 ++++++------
 2 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index b26028c..157a156 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -195,7 +195,7 @@ static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table)
 
     l2_table = *table;
 
-    if (old_l2_offset == 0) {
+    if ((old_l2_offset & L1E_OFFSET_MASK) == 0) {
         /* if there was no old l2 table, clear the new table */
         memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
     } else {
@@ -203,7 +203,8 @@ static int l2_allocate(BlockDriverState *bs, int l1_index, uint64_t **table)
 
         /* if there was an old l2 table, read it from the disk */
         BLKDBG_EVENT(bs->file, BLKDBG_L2_ALLOC_COW_READ);
-        ret = qcow2_cache_get(bs, s->l2_table_cache, old_l2_offset,
+        ret = qcow2_cache_get(bs, s->l2_table_cache,
+            old_l2_offset & L1E_OFFSET_MASK,
             (void**) &old_table);
         if (ret < 0) {
             goto fail;
@@ -508,13 +509,13 @@ static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
             return ret;
         }
     }
-    l2_offset = s->l1_table[l1_index];
+
+    l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK;
 
     /* seek the l2 table of the given l2 offset */
 
-    if (l2_offset & QCOW_OFLAG_COPIED) {
+    if (s->l1_table[l1_index] & QCOW_OFLAG_COPIED) {
         /* load the l2 table in memory */
-        l2_offset &= ~QCOW_OFLAG_COPIED;
         ret = l2_load(bs, l2_offset, &l2_table);
         if (ret < 0) {
             return ret;
@@ -530,7 +531,7 @@ static int get_cluster_table(BlockDriverState *bs, uint64_t offset,
         if (l2_offset) {
             qcow2_free_clusters(bs, l2_offset, s->l2_size * sizeof(uint64_t));
         }
-        l2_offset = s->l1_table[l1_index] & ~QCOW_OFLAG_COPIED;
+        l2_offset = s->l1_table[l1_index] & L1E_OFFSET_MASK;
     }
 
     /* find the cluster offset for the given disk offset */
@@ -687,8 +688,7 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
      */
     if (j != 0) {
         for (i = 0; i < j; i++) {
-            qcow2_free_any_clusters(bs,
-                be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, 1);
+            qcow2_free_any_clusters(bs, be64_to_cpu(old_cluster[i]), 1);
         }
     }
 
@@ -867,7 +867,9 @@ again:
      * Check how many clusters are already allocated and don't need COW, and how
      * many need a new allocation.
      */
-    if (cluster_offset & QCOW_OFLAG_COPIED) {
+    if (qcow2_get_cluster_type(cluster_offset) == QCOW2_CLUSTER_NORMAL
+        && (cluster_offset & QCOW_OFLAG_COPIED))
+    {
         /* We keep all QCOW_OFLAG_COPIED clusters */
         keep_clusters = count_contiguous_clusters(nb_clusters, s->cluster_size,
                                                   &l2_table[l2_index], 0,
@@ -886,7 +888,7 @@ again:
         cluster_offset = 0;
     }
 
-    cluster_offset &= ~QCOW_OFLAG_COPIED;
+    cluster_offset &= L2E_OFFSET_MASK;
 
     /* If there is something left to allocate, do that now */
     *m = (QCowL2Meta) {
@@ -1041,9 +1043,7 @@ static int discard_single_l2(BlockDriverState *bs, uint64_t offset,
         uint64_t old_offset;
 
         old_offset = be64_to_cpu(l2_table[l2_index + i]);
-        old_offset &= ~QCOW_OFLAG_COPIED;
-
-        if (old_offset == 0) {
+        if ((old_offset & L2E_OFFSET_MASK) == 0) {
             continue;
         }
 
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index f39928a..7c95fe3 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -696,9 +696,8 @@ void qcow2_free_any_clusters(BlockDriverState *bs,
         return;
     }
 
-    qcow2_free_clusters(bs, cluster_offset, nb_clusters << s->cluster_bits);
-
-    return;
+    qcow2_free_clusters(bs, cluster_offset & L2E_OFFSET_MASK,
+                        nb_clusters << s->cluster_bits);
 }
 
 
@@ -758,7 +757,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
         l2_offset = l1_table[i];
         if (l2_offset) {
             old_l2_offset = l2_offset;
-            l2_offset &= ~QCOW_OFLAG_COPIED;
+            l2_offset &= L1E_OFFSET_MASK;
 
             ret = qcow2_cache_get(bs, s->l2_table_cache, l2_offset,
                 (void**) &l2_table);
@@ -790,10 +789,11 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
                         /* compressed clusters are never modified */
                         refcount = 2;
                     } else {
+                        uint64_t cluster_index = (offset & L2E_OFFSET_MASK) >> s->cluster_bits;
                         if (addend != 0) {
-                            refcount = update_cluster_refcount(bs, offset >> s->cluster_bits, addend);
+                            refcount = update_cluster_refcount(bs, cluster_index, addend);
                         } else {
-                            refcount = get_refcount(bs, offset >> s->cluster_bits);
+                            refcount = get_refcount(bs, cluster_index);
                         }
 
                         if (refcount < 0) {
-- 
1.7.6.5