[Qemu-devel] [PATCH v3 4/8] qcow2-refcount: Move OFLAG_COPIED checks

[Max Reitz <mreitz@redhat.com>]

Move the OFLAG_COPIED checks out of check_refcounts_l1 and
check_refcounts_l2 and after the actual refcount checks/fixes (since the
refcounts might actually change there).

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/qcow2-refcount.c | 99 +++++++++++++++++++++++++++++++++-----------------
 1 file changed, 65 insertions(+), 34 deletions(-)

diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 310efcc..fdc0f86 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -1035,7 +1035,7 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
     BDRVQcowState *s = bs->opaque;
     uint64_t *l2_table, l2_entry;
     uint64_t next_contiguous_offset = 0;
-    int i, l2_size, nb_csectors, refcount;
+    int i, l2_size, nb_csectors;
 
     /* Read L2 table from disk */
     l2_size = s->l2_size * sizeof(uint64_t);
@@ -1087,23 +1087,8 @@ static int check_refcounts_l2(BlockDriverState *bs, BdrvCheckResult *res,
 
         case QCOW2_CLUSTER_NORMAL:
         {
-            /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
             uint64_t offset = l2_entry & L2E_OFFSET_MASK;
 
-            if (flags & CHECK_OFLAG_COPIED) {
-                refcount = get_refcount(bs, offset >> s->cluster_bits);
-                if (refcount < 0) {
-                    fprintf(stderr, "Can't get refcount for offset %"
-                        PRIx64 ": %s\n", l2_entry, strerror(-refcount));
-                    goto fail;
-                }
-                if ((refcount == 1) != ((l2_entry & QCOW_OFLAG_COPIED) != 0)) {
-                    fprintf(stderr, "ERROR OFLAG_COPIED: offset=%"
-                        PRIx64 " refcount=%d\n", l2_entry, refcount);
-                    res->corruptions++;
-                }
-            }
-
             if (flags & CHECK_FRAG_INFO) {
                 res->bfi.allocated_clusters++;
                 if (next_contiguous_offset &&
@@ -1160,7 +1145,7 @@ static int check_refcounts_l1(BlockDriverState *bs,
 {
     BDRVQcowState *s = bs->opaque;
     uint64_t *l1_table, l2_offset, l1_size2;
-    int i, refcount, ret;
+    int i, ret;
 
     l1_size2 = l1_size * sizeof(uint64_t);
 
@@ -1184,22 +1169,6 @@ static int check_refcounts_l1(BlockDriverState *bs,
     for(i = 0; i < l1_size; i++) {
         l2_offset = l1_table[i];
         if (l2_offset) {
-            /* QCOW_OFLAG_COPIED must be set iff refcount == 1 */
-            if (flags & CHECK_OFLAG_COPIED) {
-                refcount = get_refcount(bs, (l2_offset & ~QCOW_OFLAG_COPIED)
-                    >> s->cluster_bits);
-                if (refcount < 0) {
-                    fprintf(stderr, "Can't get refcount for l2_offset %"
-                        PRIx64 ": %s\n", l2_offset, strerror(-refcount));
-                    goto fail;
-                }
-                if ((refcount == 1) != ((l2_offset & QCOW_OFLAG_COPIED) != 0)) {
-                    fprintf(stderr, "ERROR OFLAG_COPIED: l2_offset=%" PRIx64
-                        " refcount=%d\n", l2_offset, refcount);
-                    res->corruptions++;
-                }
-            }
-
             /* Mark L2 table as used */
             l2_offset &= L1E_OFFSET_MASK;
             inc_refcounts(bs, res, refcount_table, refcount_table_size,
@@ -1241,7 +1210,8 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 {
     BDRVQcowState *s = bs->opaque;
     int64_t size, i, highest_cluster;
-    int nb_clusters, refcount1, refcount2;
+    uint64_t *l2_table = NULL;
+    int nb_clusters, refcount1, refcount2, j;
     QCowSnapshot *sn;
     uint16_t *refcount_table;
     int ret;
@@ -1365,10 +1335,71 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
         }
     }
 
+    l2_table = qemu_blockalign(bs, s->cluster_size);
+
+    /* check OFLAG_COPIED */
+    for (i = 0; i < s->l1_size; i++) {
+        uint64_t l1_entry = s->l1_table[i];
+        uint64_t l2_offset = l1_entry & L1E_OFFSET_MASK;
+        int refcount;
+
+        if (!l2_offset) {
+            continue;
+        }
+
+        refcount = get_refcount(bs, l2_offset >> s->cluster_bits);
+        if (refcount < 0) {
+            /* don't print message nor increment check_errors, since the above
+             * loop will have done this already */
+            continue;
+        }
+        if ((refcount == 1) != ((l1_entry & QCOW_OFLAG_COPIED) != 0)) {
+            fprintf(stderr, "ERROR OFLAG_COPIED L2 cluster: l1_entry=%" PRIx64
+                    " refcount=%d\n",
+                    l1_entry, refcount);
+            res->corruptions++;
+        }
+
+        ret = bdrv_pread(bs->file, l2_offset, l2_table,
+                s->l2_size * sizeof(uint64_t));
+        if (ret < 0) {
+            fprintf(stderr, "ERROR: Could not read L2 table: %s\n",
+                    strerror(-ret));
+            res->check_errors++;
+            goto fail;
+        }
+
+        for (j = 0; j < s->l2_size; j++) {
+            uint64_t l2_entry = be64_to_cpu(l2_table[j]);
+            uint64_t data_offset;
+
+            if (qcow2_get_cluster_type(l2_entry) != QCOW2_CLUSTER_NORMAL) {
+                continue;
+            }
+
+            data_offset = l2_entry & L2E_OFFSET_MASK;
+
+            refcount = get_refcount(bs, data_offset >> s->cluster_bits);
+            if (refcount < 0) {
+                /* don't print message nor increment check_errors, since the
+                 * above loop will have done this already */
+                continue;
+            }
+            if ((refcount == 1) != ((l2_entry & QCOW_OFLAG_COPIED) != 0)) {
+                fprintf(stderr, "ERROR OFLAG_COPIED data cluster: l2_entry=%"
+                        PRIx64 " refcount=%d\n",
+                        l2_entry, refcount);
+                res->corruptions++;
+            }
+        }
+    }
+
+
     res->image_end_offset = (highest_cluster + 1) * s->cluster_size;
     ret = 0;
 
 fail:
+    qemu_vfree(l2_table);
     g_free(refcount_table);
 
     return ret;
-- 
1.8.3.1