[Qemu-devel] [PULL 26/61] qcow2: Use negated overflow check mask

[Kevin Wolf <kwolf@redhat.com>]

From: Max Reitz <mreitz@redhat.com>

In qcow2_check_metadata_overlap and qcow2_pre_write_overlap_check,
change the parameter signifying the checks to perform from its current
positive form to a negative one, i.e., it will no longer explicitly
specify every check to perform but rather a mask of checks not to
perform.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/qcow2-cache.c    |  8 +++-----
 block/qcow2-cluster.c  | 16 +++++++---------
 block/qcow2-refcount.c | 22 ++++++++++------------
 block/qcow2-snapshot.c | 12 +++++-------
 block/qcow2.c          |  5 ++---
 block/qcow2.h          |  4 ++--
 6 files changed, 29 insertions(+), 38 deletions(-)

diff --git a/block/qcow2-cache.c b/block/qcow2-cache.c
index 40a5a3f..8ecbb5b 100644
--- a/block/qcow2-cache.c
+++ b/block/qcow2-cache.c
@@ -115,15 +115,13 @@ static int qcow2_cache_entry_flush(BlockDriverState *bs, Qcow2Cache *c, int i)
     }
 
     if (c == s->refcount_block_cache) {
-        ret = qcow2_pre_write_overlap_check(bs,
-                QCOW2_OL_DEFAULT & ~QCOW2_OL_REFCOUNT_BLOCK,
+        ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_REFCOUNT_BLOCK,
                 c->entries[i].offset, s->cluster_size);
     } else if (c == s->l2_table_cache) {
-        ret = qcow2_pre_write_overlap_check(bs,
-                QCOW2_OL_DEFAULT & ~QCOW2_OL_ACTIVE_L2,
+        ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L2,
                 c->entries[i].offset, s->cluster_size);
     } else {
-        ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
+        ret = qcow2_pre_write_overlap_check(bs, 0,
                 c->entries[i].offset, s->cluster_size);
     }
 
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 0fd26bb..0348b97 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -83,8 +83,8 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
 
     /* the L1 position has not yet been updated, so these clusters must
      * indeed be completely free */
-    ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
-                                        new_l1_table_offset, new_l1_size2);
+    ret = qcow2_pre_write_overlap_check(bs, 0, new_l1_table_offset,
+                                        new_l1_size2);
     if (ret < 0) {
         goto fail;
     }
@@ -160,8 +160,7 @@ int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index)
         buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]);
     }
 
-    ret = qcow2_pre_write_overlap_check(bs,
-            QCOW2_OL_DEFAULT & ~QCOW2_OL_ACTIVE_L1,
+    ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
             s->l1_table_offset + 8 * l1_start_index, sizeof(buf));
     if (ret < 0) {
         return ret;
@@ -396,7 +395,7 @@ static int coroutine_fn copy_sectors(BlockDriverState *bs,
                         &s->aes_encrypt_key);
     }
 
-    ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
+    ret = qcow2_pre_write_overlap_check(bs, 0,
             cluster_offset + n_start * BDRV_SECTOR_SIZE, n * BDRV_SECTOR_SIZE);
     if (ret < 0) {
         goto out;
@@ -1604,8 +1603,7 @@ static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table,
                 }
             }
 
-            ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
-                                                offset, s->cluster_size);
+            ret = qcow2_pre_write_overlap_check(bs, 0, offset, s->cluster_size);
             if (ret < 0) {
                 if (!preallocated) {
                     qcow2_free_clusters(bs, offset, s->cluster_size,
@@ -1661,8 +1659,8 @@ static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table,
             }
         } else {
             if (l2_dirty) {
-                ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT &
-                        ~(QCOW2_OL_INACTIVE_L2 | QCOW2_OL_ACTIVE_L2), l2_offset,
+                ret = qcow2_pre_write_overlap_check(bs,
+                        QCOW2_OL_INACTIVE_L2 | QCOW2_OL_ACTIVE_L2, l2_offset,
                         s->cluster_size);
                 if (ret < 0) {
                     goto fail;
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 4ef6899..988644a 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -1311,9 +1311,8 @@ static int check_oflag_copied(BlockDriverState *bs, BdrvCheckResult *res,
         }
 
         if (l2_dirty) {
-            ret = qcow2_pre_write_overlap_check(bs,
-                    QCOW2_OL_DEFAULT & ~QCOW2_OL_ACTIVE_L2, l2_offset,
-                    s->cluster_size);
+            ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L2,
+                                                l2_offset, s->cluster_size);
             if (ret < 0) {
                 fprintf(stderr, "ERROR: Could not write L2 table; metadata "
                         "overlap check failed: %s\n", strerror(-ret));
@@ -1354,8 +1353,7 @@ static int write_reftable_entry(BlockDriverState *bs, int rt_index)
         buf[i] = cpu_to_be64(s->refcount_table[rt_start_index + i]);
     }
 
-    ret = qcow2_pre_write_overlap_check(bs,
-            QCOW2_OL_DEFAULT & ~QCOW2_OL_REFCOUNT_TABLE,
+    ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_REFCOUNT_TABLE,
             s->refcount_table_offset + rt_start_index * sizeof(uint64_t),
             sizeof(buf));
     if (ret < 0) {
@@ -1406,8 +1404,7 @@ static int64_t realloc_refcount_block(BlockDriverState *bs, int reftable_index,
 
     /* new block has not yet been entered into refcount table, therefore it is
      * no refcount block yet (regarding this check) */
-    ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, new_offset,
-            s->cluster_size);
+    ret = qcow2_pre_write_overlap_check(bs, 0, new_offset, s->cluster_size);
     if (ret < 0) {
         fprintf(stderr, "Could not write refcount block; metadata overlap "
                 "check failed: %s\n", strerror(-ret));
@@ -1639,8 +1636,8 @@ fail:
  * looking for overlaps with important metadata sections (L1/L2 tables etc.),
  * i.e. a sanity check without relying on the refcount tables.
  *
- * The chk parameter specifies exactly what checks to perform (being a bitmask
- * of QCow2MetadataOverlap values).
+ * The ign parameter specifies what checks not to perform (being a bitmask of
+ * QCow2MetadataOverlap values), i.e., what sections to ignore.
  *
  * Returns:
  * - 0 if writing to this offset will not affect the mentioned metadata
@@ -1648,10 +1645,11 @@ fail:
  * - a negative value (-errno) indicating an error while performing a check,
  *   e.g. when bdrv_read failed on QCOW2_OL_INACTIVE_L2
  */
-int qcow2_check_metadata_overlap(BlockDriverState *bs, int chk, int64_t offset,
+int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset,
                                  int64_t size)
 {
     BDRVQcowState *s = bs->opaque;
+    int chk = QCOW2_OL_DEFAULT & ~ign;
     int i, j;
 
     if (!size) {
@@ -1767,10 +1765,10 @@ static const char *metadata_ol_names[] = {
  * Returns 0 if there were neither overlaps nor errors while checking for
  * overlaps; or a negative value (-errno) on error.
  */
-int qcow2_pre_write_overlap_check(BlockDriverState *bs, int chk, int64_t offset,
+int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset,
                                   int64_t size)
 {
-    int ret = qcow2_check_metadata_overlap(bs, chk, offset, size);
+    int ret = qcow2_check_metadata_overlap(bs, ign, offset, size);
 
     if (ret < 0) {
         return ret;
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 884b06d..3529c68 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -192,8 +192,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
 
     /* The snapshot list position has not yet been updated, so these clusters
      * must indeed be completely free */
-    ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, offset,
-                                        snapshots_size);
+    ret = qcow2_pre_write_overlap_check(bs, 0, offset, snapshots_size);
     if (ret < 0) {
         goto fail;
     }
@@ -395,8 +394,8 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
         l1_table[i] = cpu_to_be64(s->l1_table[i]);
     }
 
-    ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
-            sn->l1_table_offset, s->l1_size * sizeof(uint64_t));
+    ret = qcow2_pre_write_overlap_check(bs, 0, sn->l1_table_offset,
+                                        s->l1_size * sizeof(uint64_t));
     if (ret < 0) {
         goto fail;
     }
@@ -521,9 +520,8 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
         goto fail;
     }
 
-    ret = qcow2_pre_write_overlap_check(bs,
-            QCOW2_OL_DEFAULT & ~QCOW2_OL_ACTIVE_L1,
-            s->l1_table_offset, cur_l1_bytes);
+    ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_ACTIVE_L1,
+                                        s->l1_table_offset, cur_l1_bytes);
     if (ret < 0) {
         goto fail;
     }
diff --git a/block/qcow2.c b/block/qcow2.c
index 3d1e74d..c461471 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -965,7 +965,7 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
                 cur_nr_sectors * 512);
         }
 
-        ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
+        ret = qcow2_pre_write_overlap_check(bs, 0,
                 cluster_offset + index_in_cluster * BDRV_SECTOR_SIZE,
                 cur_nr_sectors * BDRV_SECTOR_SIZE);
         if (ret < 0) {
@@ -1751,8 +1751,7 @@ static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num,
         }
         cluster_offset &= s->cluster_offset_mask;
 
-        ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT,
-                cluster_offset, out_len);
+        ret = qcow2_pre_write_overlap_check(bs, 0, cluster_offset, out_len);
         if (ret < 0) {
             goto fail;
         }
diff --git a/block/qcow2.h b/block/qcow2.h
index 455e38d..8692011 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -433,9 +433,9 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 
 void qcow2_process_discards(BlockDriverState *bs, int ret);
 
-int qcow2_check_metadata_overlap(BlockDriverState *bs, int chk, int64_t offset,
+int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset,
                                  int64_t size);
-int qcow2_pre_write_overlap_check(BlockDriverState *bs, int chk, int64_t offset,
+int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset,
                                   int64_t size);
 
 /* qcow2-cluster.c functions */
-- 
1.8.1.4