Merge tag 'pull-parallels-2023-09-06' of https://src.openvz.org/scm/~den/qemu into staging

Parallels format driver changes:
  * Fix comments formatting inside parallels driver
  * Incorrect data end calculation in parallels_open()
  * Check if data_end greater than the file size
  * Add "explicit" argument to parallels_check_leak()
  * Add data_start field to BDRVParallelsState
  * Add checking and repairing duplicate offsets in BAT
  * Image repairing in parallels_open()
  * Use bdrv_co_getlength() in parallels_check_outside_image()
  * Add data_off check
  * Add data_off repairing to parallels_open()
  * Fix record in MAINTAINERS

Parallels format driver tests:
  * Add out-of-image check test for parallels format
  * Add leak check test for parallels format
  * Add test for BAT entries duplication check
  * Refactor tests of parallels images checks (131)
  * Fix cluster size in parallels images tests (131)
  * Fix test 131 after repair was added to parallels_open()
  * Add test for data_off check

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# gpg: Signature made Wed 06 Sep 2023 11:39:52 EDT
# gpg:                using RSA key F6F1367F707CF91519227CAD3F30A5AE93779C9F
# gpg:                issuer "den@openvz.org"
# gpg: Good signature from "Denis V. Lunev <den@openvz.org>" [unknown]
# gpg: WARNING: The key's User ID is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: F6F1 367F 707C F915 1922  7CAD 3F30 A5AE 9377 9C9F

* tag 'pull-parallels-2023-09-06' of https://src.openvz.org/scm/~den/qemu:
  iotests: Add test for data_off check
  iotests: Fix test 131 after repair was added to parallels_open()
  iotests: Fix cluster size in parallels images tests (131)
  iotests: Refactor tests of parallels images checks (131)
  iotests: Add test for BAT entries duplication check
  iotests: Add leak check test for parallels format
  iotests: Add out-of-image check test for parallels format
  parallels: Add data_off repairing to parallels_open()
  parallels: Add data_off check
  parallels: Use bdrv_co_getlength() in parallels_check_outside_image()
  parallels: Image repairing in parallels_open()
  parallels: Add checking and repairing duplicate offsets in BAT
  parallels: Add data_start field to BDRVParallelsState
  parallels: Add "explicit" argument to parallels_check_leak()
  parallels: Check if data_end greater than the file size
  parallels: Incorrect data end calculation in parallels_open()
  parallels: Fix comments formatting inside parallels driver
  MAINTAINERS: add tree to keep parallels format driver changes

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

7 files changed, 564 insertions, 99 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 3b29568ed4..b471973e1e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3693,6 +3693,7 @@ S: Supported
 F: block/parallels.c
 F: block/parallels-ext.c
 F: docs/interop/parallels.txt
+T: git https://src.openvz.org/scm/~den/qemu.git parallels
 
 qed
 M: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/block/parallels.c b/block/parallels.c
index 18e34aef28..48c32d6821 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -136,6 +136,12 @@ static int cluster_remainder(BDRVParallelsState *s, int64_t sector_num,
     return MIN(nb_sectors, ret);
 }
 
+static uint32_t host_cluster_index(BDRVParallelsState *s, int64_t off)
+{
+    off -= s->data_start << BDRV_SECTOR_BITS;
+    return off / s->cluster_size;
+}
+
 static int64_t block_status(BDRVParallelsState *s, int64_t sector_num,
                             int nb_sectors, int *pnum)
 {
@@ -188,7 +194,8 @@ allocate_clusters(BlockDriverState *bs, int64_t sector_num,
     idx = sector_num / s->tracks;
     to_allocate = DIV_ROUND_UP(sector_num + *pnum, s->tracks) - idx;
 
-    /* This function is called only by parallels_co_writev(), which will never
+    /*
+     * This function is called only by parallels_co_writev(), which will never
      * pass a sector_num at or beyond the end of the image (because the block
      * layer never passes such a sector_num to that function). Therefore, idx
      * is always below s->bat_size.
@@ -196,7 +203,8 @@ allocate_clusters(BlockDriverState *bs, int64_t sector_num,
      * exceed the image end. Therefore, idx + to_allocate cannot exceed
      * s->bat_size.
      * Note that s->bat_size is an unsigned int, therefore idx + to_allocate
-     * will always fit into a uint32_t. */
+     * will always fit into a uint32_t.
+     */
     assert(idx < s->bat_size && idx + to_allocate <= s->bat_size);
 
     space = to_allocate * s->tracks;
@@ -230,13 +238,15 @@ allocate_clusters(BlockDriverState *bs, int64_t sector_num,
         }
     }
 
-    /* Try to read from backing to fill empty clusters
+    /*
+     * Try to read from backing to fill empty clusters
      * FIXME: 1. previous write_zeroes may be redundant
      *        2. most of data we read from backing will be rewritten by
      *           parallels_co_writev. On aligned-to-cluster write we do not need
      *           this read at all.
      *        3. it would be good to combine write of data from backing and new
-     *           data into one write call */
+     *           data into one write call.
+     */
     if (bs->backing) {
         int64_t nb_cow_sectors = to_allocate * s->tracks;
         int64_t nb_cow_bytes = nb_cow_sectors << BDRV_SECTOR_BITS;
@@ -440,6 +450,81 @@ static void parallels_check_unclean(BlockDriverState *bs,
     }
 }
 
+/*
+ * Returns true if data_off is correct, otherwise false. In both cases
+ * correct_offset is set to the proper value.
+ */
+static bool parallels_test_data_off(BDRVParallelsState *s,
+                                    int64_t file_nb_sectors,
+                                    uint32_t *correct_offset)
+{
+    uint32_t data_off, min_off;
+    bool old_magic;
+
+    /*
+     * There are two slightly different image formats: with "WithoutFreeSpace"
+     * or "WithouFreSpacExt" magic words. Call the first one as "old magic".
+     * In such images data_off field can be zero. In this case the offset is
+     * calculated as the end of BAT table plus some padding to ensure sector
+     * size alignment.
+     */
+    old_magic = !memcmp(s->header->magic, HEADER_MAGIC, 16);
+
+    min_off = DIV_ROUND_UP(bat_entry_off(s->bat_size), BDRV_SECTOR_SIZE);
+    if (!old_magic) {
+        min_off = ROUND_UP(min_off, s->cluster_size / BDRV_SECTOR_SIZE);
+    }
+
+    if (correct_offset) {
+        *correct_offset = min_off;
+    }
+
+    data_off = le32_to_cpu(s->header->data_off);
+    if (data_off == 0 && old_magic) {
+        return true;
+    }
+
+    if (data_off < min_off || data_off > file_nb_sectors) {
+        return false;
+    }
+
+    if (correct_offset) {
+        *correct_offset = data_off;
+    }
+
+    return true;
+}
+
+static int coroutine_fn GRAPH_RDLOCK
+parallels_check_data_off(BlockDriverState *bs, BdrvCheckResult *res,
+                         BdrvCheckMode fix)
+{
+    BDRVParallelsState *s = bs->opaque;
+    int64_t file_size;
+    uint32_t data_off;
+
+    file_size = bdrv_co_nb_sectors(bs->file->bs);
+    if (file_size < 0) {
+        res->check_errors++;
+        return file_size;
+    }
+
+    if (parallels_test_data_off(s, file_size, &data_off)) {
+        return 0;
+    }
+
+    res->corruptions++;
+    if (fix & BDRV_FIX_ERRORS) {
+        s->header->data_off = cpu_to_le32(data_off);
+        res->corruptions_fixed++;
+    }
+
+    fprintf(stderr, "%s data_off field has incorrect value\n",
+            fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR");
+
+    return 0;
+}
+
 static int coroutine_fn GRAPH_RDLOCK
 parallels_check_outside_image(BlockDriverState *bs, BdrvCheckResult *res,
                               BdrvCheckMode fix)
@@ -484,13 +569,13 @@ parallels_check_outside_image(BlockDriverState *bs, BdrvCheckResult *res,
 
 static int coroutine_fn GRAPH_RDLOCK
 parallels_check_leak(BlockDriverState *bs, BdrvCheckResult *res,
-                     BdrvCheckMode fix)
+                     BdrvCheckMode fix, bool explicit)
 {
     BDRVParallelsState *s = bs->opaque;
     int64_t size;
     int ret;
 
-    size = bdrv_getlength(bs->file->bs);
+    size = bdrv_co_getlength(bs->file->bs);
     if (size < 0) {
         res->check_errors++;
         return size;
@@ -499,10 +584,13 @@ parallels_check_leak(BlockDriverState *bs, BdrvCheckResult *res,
     if (size > res->image_end_offset) {
         int64_t count;
         count = DIV_ROUND_UP(size - res->image_end_offset, s->cluster_size);
-        fprintf(stderr, "%s space leaked at the end of the image %" PRId64 "\n",
-                fix & BDRV_FIX_LEAKS ? "Repairing" : "ERROR",
-                size - res->image_end_offset);
-        res->leaks += count;
+        if (explicit) {
+            fprintf(stderr,
+                    "%s space leaked at the end of the image %" PRId64 "\n",
+                    fix & BDRV_FIX_LEAKS ? "Repairing" : "ERROR",
+                    size - res->image_end_offset);
+            res->leaks += count;
+        }
         if (fix & BDRV_FIX_LEAKS) {
             Error *local_err = NULL;
 
@@ -517,13 +605,148 @@ parallels_check_leak(BlockDriverState *bs, BdrvCheckResult *res,
                 res->check_errors++;
                 return ret;
             }
-            res->leaks_fixed += count;
+            if (explicit) {
+                res->leaks_fixed += count;
+            }
         }
     }
 
     return 0;
 }
 
+static int coroutine_fn GRAPH_RDLOCK
+parallels_check_duplicate(BlockDriverState *bs, BdrvCheckResult *res,
+                          BdrvCheckMode fix)
+{
+    BDRVParallelsState *s = bs->opaque;
+    int64_t host_off, host_sector, guest_sector;
+    unsigned long *bitmap;
+    uint32_t i, bitmap_size, cluster_index, bat_entry;
+    int n, ret = 0;
+    uint64_t *buf = NULL;
+    bool fixed = false;
+
+    /*
+     * Create a bitmap of used clusters.
+     * If a bit is set, there is a BAT entry pointing to this cluster.
+     * Loop through the BAT entries, check bits relevant to an entry offset.
+     * If bit is set, this entry is duplicated. Otherwise set the bit.
+     *
+     * We shouldn't worry about newly allocated clusters outside the image
+     * because they are created higher then any existing cluster pointed by
+     * a BAT entry.
+     */
+    bitmap_size = host_cluster_index(s, res->image_end_offset);
+    if (bitmap_size == 0) {
+        return 0;
+    }
+    if (res->image_end_offset % s->cluster_size) {
+        /* A not aligned image end leads to a bitmap shorter by 1 */
+        bitmap_size++;
+    }
+
+    bitmap = bitmap_new(bitmap_size);
+
+    buf = qemu_blockalign(bs, s->cluster_size);
+
+    for (i = 0; i < s->bat_size; i++) {
+        host_off = bat2sect(s, i) << BDRV_SECTOR_BITS;
+        if (host_off == 0) {
+            continue;
+        }
+
+        cluster_index = host_cluster_index(s, host_off);
+        assert(cluster_index < bitmap_size);
+        if (!test_bit(cluster_index, bitmap)) {
+            bitmap_set(bitmap, cluster_index, 1);
+            continue;
+        }
+
+        /* this cluster duplicates another one */
+        fprintf(stderr, "%s duplicate offset in BAT entry %u\n",
+                fix & BDRV_FIX_ERRORS ? "Repairing" : "ERROR", i);
+
+        res->corruptions++;
+
+        if (!(fix & BDRV_FIX_ERRORS)) {
+            continue;
+        }
+
+        /*
+         * Reset the entry and allocate a new cluster
+         * for the relevant guest offset. In this way we let
+         * the lower layer to place the new cluster properly.
+         * Copy the original cluster to the allocated one.
+         * But before save the old offset value for repairing
+         * if we have an error.
+         */
+        bat_entry = s->bat_bitmap[i];
+        parallels_set_bat_entry(s, i, 0);
+
+        ret = bdrv_co_pread(bs->file, host_off, s->cluster_size, buf, 0);
+        if (ret < 0) {
+            res->check_errors++;
+            goto out_repair_bat;
+        }
+
+        guest_sector = (i * (int64_t)s->cluster_size) >> BDRV_SECTOR_BITS;
+        host_sector = allocate_clusters(bs, guest_sector, s->tracks, &n);
+        if (host_sector < 0) {
+            res->check_errors++;
+            goto out_repair_bat;
+        }
+        host_off = host_sector << BDRV_SECTOR_BITS;
+
+        ret = bdrv_co_pwrite(bs->file, host_off, s->cluster_size, buf, 0);
+        if (ret < 0) {
+            res->check_errors++;
+            goto out_repair_bat;
+        }
+
+        if (host_off + s->cluster_size > res->image_end_offset) {
+            res->image_end_offset = host_off + s->cluster_size;
+        }
+
+        /*
+         * In the future allocate_cluster() will reuse holed offsets
+         * inside the image. Keep the used clusters bitmap content
+         * consistent for the new allocated clusters too.
+         *
+         * Note, clusters allocated outside the current image are not
+         * considered, and the bitmap size doesn't change.
+         */
+        cluster_index = host_cluster_index(s, host_off);
+        if (cluster_index < bitmap_size) {
+            bitmap_set(bitmap, cluster_index, 1);
+        }
+
+        fixed = true;
+        res->corruptions_fixed++;
+
+    }
+
+    if (fixed) {
+        /*
+         * When new clusters are allocated, the file size increases by
+         * 128 Mb. We need to truncate the file to the right size. Let
+         * the leak fix code make its job without res changing.
+         */
+        ret = parallels_check_leak(bs, res, fix, false);
+    }
+
+out_free:
+    g_free(buf);
+    g_free(bitmap);
+    return ret;
+/*
+ * We can get here only from places where index and old_offset have
+ * meaningful values.
+ */
+out_repair_bat:
+    s->bat_bitmap[i] = bat_entry;
+    goto out_free;
+}
+
 static void parallels_collect_statistics(BlockDriverState *bs,
                                          BdrvCheckResult *res,
                                          BdrvCheckMode fix)
@@ -565,12 +788,22 @@ parallels_co_check(BlockDriverState *bs, BdrvCheckResult *res,
     WITH_QEMU_LOCK_GUARD(&s->lock) {
         parallels_check_unclean(bs, res, fix);
 
+        ret = parallels_check_data_off(bs, res, fix);
+        if (ret < 0) {
+            return ret;
+        }
+
         ret = parallels_check_outside_image(bs, res, fix);
         if (ret < 0) {
             return ret;
         }
 
-        ret = parallels_check_leak(bs, res, fix);
+        ret = parallels_check_leak(bs, res, fix, true);
+        if (ret < 0) {
+            return ret;
+        }
+
+        ret = parallels_check_duplicate(bs, res, fix);
         if (ret < 0) {
             return ret;
         }
@@ -798,10 +1031,12 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
     BDRVParallelsState *s = bs->opaque;
     ParallelsHeader ph;
     int ret, size, i;
-    int64_t file_nb_sectors;
+    int64_t file_nb_sectors, sector;
+    uint32_t data_start;
     QemuOpts *opts = NULL;
     Error *local_err = NULL;
     char *buf;
+    bool data_off_is_correct;
 
     ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
     if (ret < 0) {
@@ -859,15 +1094,6 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
         ret = -ENOMEM;
         goto fail;
     }
-    s->data_end = le32_to_cpu(ph.data_off);
-    if (s->data_end == 0) {
-        s->data_end = ROUND_UP(bat_entry_off(s->bat_size), BDRV_SECTOR_SIZE);
-    }
-    if (s->data_end < s->header_size) {
-        /* there is not enough unused space to fit to block align between BAT
-           and actual data. We can't avoid read-modify-write... */
-        s->header_size = size;
-    }
 
     ret = bdrv_pread(bs->file, 0, s->header_size, s->header, 0);
     if (ret < 0) {
@@ -875,33 +1101,20 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
     }
     s->bat_bitmap = (uint32_t *)(s->header + 1);
 
-    for (i = 0; i < s->bat_size; i++) {
-        int64_t off = bat2sect(s, i);
-        if (off >= file_nb_sectors) {
-            if (flags & BDRV_O_CHECK) {
-                continue;
-            }
-            error_setg(errp, "parallels: Offset %" PRIi64 " in BAT[%d] entry "
-                       "is larger than file size (%" PRIi64 ")",
-                       off << BDRV_SECTOR_BITS, i,
-                       file_nb_sectors << BDRV_SECTOR_BITS);
-            ret = -EINVAL;
-            goto fail;
-        }
-        if (off >= s->data_end) {
-            s->data_end = off + s->tracks;
-        }
-    }
-
     if (le32_to_cpu(ph.inuse) == HEADER_INUSE_MAGIC) {
-        /* Image was not closed correctly. The check is mandatory */
         s->header_unclean = true;
-        if ((flags & BDRV_O_RDWR) && !(flags & BDRV_O_CHECK)) {
-            error_setg(errp, "parallels: Image was not closed correctly; "
-                       "cannot be opened read/write");
-            ret = -EACCES;
-            goto fail;
-        }
+    }
+
+    data_off_is_correct = parallels_test_data_off(s, file_nb_sectors,
+                                                  &data_start);
+    s->data_start = data_start;
+    s->data_end = s->data_start;
+    if (s->data_end < (s->header_size >> BDRV_SECTOR_BITS)) {
+        /*
+         * There is not enough unused space to fit to block align between BAT
+         * and actual data. We can't avoid read-modify-write...
+         */
+        s->header_size = size;
     }
 
     opts = qemu_opts_create(&parallels_runtime_opts, NULL, 0, errp);
@@ -962,10 +1175,41 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
                bdrv_get_device_or_node_name(bs));
     ret = migrate_add_blocker(s->migration_blocker, errp);
     if (ret < 0) {
-        error_free(s->migration_blocker);
+        error_setg(errp, "Migration blocker error");
         goto fail;
     }
     qemu_co_mutex_init(&s->lock);
+
+    for (i = 0; i < s->bat_size; i++) {
+        sector = bat2sect(s, i);
+        if (sector + s->tracks > s->data_end) {
+            s->data_end = sector + s->tracks;
+        }
+    }
+
+    /*
+     * We don't repair the image here if it's opened for checks. Also we don't
+     * want to change inactive images and can't change readonly images.
+     */
+    if ((flags & (BDRV_O_CHECK | BDRV_O_INACTIVE)) || !(flags & BDRV_O_RDWR)) {
+        return 0;
+    }
+
+    /*
+     * Repair the image if it's dirty or
+     * out-of-image corruption was detected.
+     */
+    if (s->data_end > file_nb_sectors || s->header_unclean
+        || !data_off_is_correct) {
+        BdrvCheckResult res;
+        ret = bdrv_check(bs, &res, BDRV_FIX_ERRORS | BDRV_FIX_LEAKS);
+        if (ret < 0) {
+            error_setg_errno(errp, -ret, "Could not repair corrupted image");
+            migrate_del_blocker(s->migration_blocker);
+            goto fail;
+        }
+    }
+
     return 0;
 
 fail_format:
@@ -973,6 +1217,12 @@ fail_format:
 fail_options:
     ret = -EINVAL;
 fail:
+    /*
+     * "s" object was allocated by g_malloc0 so we can safely
+     * try to free its fields even they were not allocated.
+     */
+    error_free(s->migration_blocker);
+    g_free(s->bat_dirty_bmap);
     qemu_vfree(s->header);
     return ret;
 }
diff --git a/block/parallels.h b/block/parallels.h
index f22f43f988..4e53e9572d 100644
--- a/block/parallels.h
+++ b/block/parallels.h
@@ -75,6 +75,7 @@ typedef struct BDRVParallelsState {
     uint32_t *bat_bitmap;
     unsigned int bat_size;
 
+    int64_t  data_start;
     int64_t  data_end;
     uint64_t prealloc_size;
     ParallelsPreallocMode prealloc_mode;
diff --git a/tests/qemu-iotests/131 b/tests/qemu-iotests/131
index a847692b4c..304bbb3f61 100755
--- a/tests/qemu-iotests/131
+++ b/tests/qemu-iotests/131
@@ -44,31 +44,35 @@ _supported_os Linux
 inuse_offset=$((0x2c))
 
 size=$((64 * 1024 * 1024))
-CLUSTER_SIZE=64k
 IMGFMT=parallels
 _make_test_img $size
 
+# get cluster size in sectors from "tracks" header field
+CLUSTER_SIZE_OFFSET=28
+CLUSTER_SIZE=$(peek_file_le $TEST_IMG $CLUSTER_SIZE_OFFSET 4)
+CLUSTER_SIZE=$((CLUSTER_SIZE * 512))
+CLUSTER_HALF_SIZE=$((CLUSTER_SIZE / 2))
+CLUSTER_DBL_SIZE=$((CLUSTER_SIZE * 2))
+
 echo == read empty image ==
-{ $QEMU_IO -c "read -P 0 32k 64k" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+{ $QEMU_IO -c "read -P 0 $CLUSTER_HALF_SIZE $CLUSTER_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
 echo == write more than 1 block in a row ==
-{ $QEMU_IO -c "write -P 0x11 32k 128k" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+{ $QEMU_IO -c "write -P 0x11 $CLUSTER_HALF_SIZE $CLUSTER_DBL_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
 echo == read less than block ==
-{ $QEMU_IO -c "read -P 0x11 32k 32k" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+{ $QEMU_IO -c "read -P 0x11 $CLUSTER_HALF_SIZE $CLUSTER_HALF_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
 echo == read exactly 1 block ==
-{ $QEMU_IO -c "read -P 0x11 64k 64k" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+{ $QEMU_IO -c "read -P 0x11 $CLUSTER_SIZE $CLUSTER_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
 echo == read more than 1 block ==
-{ $QEMU_IO -c "read -P 0x11 32k 128k" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+{ $QEMU_IO -c "read -P 0x11 $CLUSTER_HALF_SIZE $CLUSTER_DBL_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
 echo == check that there is no trash after written ==
-{ $QEMU_IO -c "read -P 0 160k 32k" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+{ $QEMU_IO -c "read -P 0 $((CLUSTER_HALF_SIZE + CLUSTER_DBL_SIZE)) $CLUSTER_HALF_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
 echo == check that there is no trash before written ==
-{ $QEMU_IO -c "read -P 0 0 32k" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+{ $QEMU_IO -c "read -P 0 0 $CLUSTER_HALF_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
 
-echo "== Corrupt image =="
+echo "== corrupt image =="
 poke_file "$TEST_IMG" "$inuse_offset" "\x59\x6e\x6f\x74"
-{ $QEMU_IO -c "read -P 0x11 64k 64k" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
-_check_test_img
-_check_test_img -r all
-{ $QEMU_IO -c "read -P 0x11 64k 64k" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+echo "== read corrupted image with repairing =="
+{ $QEMU_IO -c "read -P 0x11 $CLUSTER_SIZE $CLUSTER_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
 
 echo "== allocate with backing =="
 # Verify that allocating clusters works fine even when there is a backing image.
@@ -83,7 +87,7 @@ TEST_IMG="$TEST_IMG.base" _make_test_img $size
 
 # Write some data to the base image (which would trigger an assertion failure if
 # interpreted as a QEMUIOVector)
-$QEMU_IO -c 'write -P 42 0 64k' "$TEST_IMG.base" | _filter_qemu_io
+$QEMU_IO -c "write -P 42 0 $CLUSTER_SIZE" "$TEST_IMG.base" | _filter_qemu_io
 
 # Parallels does not seem to support storing a backing filename in the image
 # itself, so we need to build our backing chain on the command line
@@ -99,8 +103,8 @@ QEMU_IO_OPTIONS=$QEMU_IO_OPTIONS_NO_FMT \
 QEMU_IO_OPTIONS=$QEMU_IO_OPTIONS_NO_FMT \
     $QEMU_IO --image-opts "$imgopts" \
     -c 'read -P 1 0 64' \
-    -c "read -P 42 64 $((64 * 1024 - 64))" \
-    -c "read -P 0 64k $((size - 64 * 1024))" \
+    -c "read -P 42 64 $((CLUSTER_SIZE - 64))" \
+    -c "read -P 0 $CLUSTER_SIZE $((size - CLUSTER_SIZE))" \
     | _filter_qemu_io
 
 # success, all done
diff --git a/tests/qemu-iotests/131.out b/tests/qemu-iotests/131.out
index de5ef7a8f5..d2904578df 100644
--- a/tests/qemu-iotests/131.out
+++ b/tests/qemu-iotests/131.out
@@ -1,53 +1,42 @@
 QA output created by 131
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
 == read empty image ==
-read 65536/65536 bytes at offset 32768
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 1048576/1048576 bytes at offset 524288
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 == write more than 1 block in a row ==
-wrote 131072/131072 bytes at offset 32768
-128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 2097152/2097152 bytes at offset 524288
+2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 == read less than block ==
-read 32768/32768 bytes at offset 32768
-32 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 524288/524288 bytes at offset 524288
+512 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 == read exactly 1 block ==
-read 65536/65536 bytes at offset 65536
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 1048576/1048576 bytes at offset 1048576
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 == read more than 1 block ==
-read 131072/131072 bytes at offset 32768
-128 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 2097152/2097152 bytes at offset 524288
+2 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 == check that there is no trash after written ==
-read 32768/32768 bytes at offset 163840
-32 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 524288/524288 bytes at offset 2621440
+512 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 == check that there is no trash before written ==
-read 32768/32768 bytes at offset 0
-32 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-== Corrupt image ==
-qemu-io: can't open device TEST_DIR/t.parallels: parallels: Image was not closed correctly; cannot be opened read/write
-ERROR image was not closed correctly
-
-1 errors were found on the image.
-Data may be corrupted, or further writes to the image may corrupt it.
+read 524288/524288 bytes at offset 0
+512 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+== corrupt image ==
+== read corrupted image with repairing ==
 Repairing image was not closed correctly
-The following inconsistencies were found and repaired:
-
-    0 leaked clusters
-    1 corruptions
-
-Double checking the fixed image now...
-No errors were found on the image.
-read 65536/65536 bytes at offset 65536
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 1048576/1048576 bytes at offset 1048576
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 == allocate with backing ==
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
 Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=67108864
-wrote 65536/65536 bytes at offset 0
-64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 wrote 64/64 bytes at offset 0
 64 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 read 64/64 bytes at offset 0
 64 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-read 65472/65472 bytes at offset 64
-63.938 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-read 67043328/67043328 bytes at offset 65536
-63.938 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 1048512/1048512 bytes at offset 64
+1023.938 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 66060288/66060288 bytes at offset 1048576
+63 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 *** done
diff --git a/tests/qemu-iotests/tests/parallels-checks b/tests/qemu-iotests/tests/parallels-checks
new file mode 100755
index 0000000000..a7a1b357b5
--- /dev/null
+++ b/tests/qemu-iotests/tests/parallels-checks
@@ -0,0 +1,145 @@
+#!/usr/bin/env bash
+# group: rw quick
+#
+# Test qemu-img check for parallels format
+#
+# Copyright (C) 2022 Virtuozzo International GmbH
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+# creator
+owner=alexander.ivanov@virtuozzo.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+status=1	# failure is the default!
+
+_cleanup()
+{
+    _cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ../common.rc
+. ../common.filter
+
+_supported_fmt parallels
+_supported_proto file
+_supported_os Linux
+
+SIZE=$((4 * 1024 * 1024))
+IMGFMT=parallels
+CLUSTER_SIZE_OFFSET=28
+DATA_OFF_OFFSET=48
+BAT_OFFSET=64
+
+_make_test_img $SIZE
+
+CLUSTER_SIZE=$(peek_file_le $TEST_IMG $CLUSTER_SIZE_OFFSET 4)
+CLUSTER_SIZE=$((CLUSTER_SIZE * 512))
+LAST_CLUSTER_OFF=$((SIZE - CLUSTER_SIZE))
+LAST_CLUSTER=$((LAST_CLUSTER_OFF/CLUSTER_SIZE))
+
+echo "== TEST OUT OF IMAGE CHECK =="
+
+echo "== write pattern =="
+{ $QEMU_IO -c "write -P 0x11 0 $SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+echo "== corrupt image =="
+cluster=$(($LAST_CLUSTER + 2))
+poke_file "$TEST_IMG" "$BAT_OFFSET" "\x$cluster\x00\x00\x00"
+
+echo "== read corrupted image with repairing =="
+{ $QEMU_IO -c "read -P 0x00 0 $CLUSTER_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+# Clear image
+_make_test_img $SIZE
+
+echo "== TEST LEAK CHECK =="
+
+echo "== write pattern to last cluster =="
+echo "write -P 0x11 $LAST_CLUSTER_OFF $CLUSTER_SIZE"
+{ $QEMU_IO -c "write -P 0x11 $LAST_CLUSTER_OFF $CLUSTER_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+file_size=`stat --printf="%s" "$TEST_IMG"`
+echo "file size: $file_size"
+
+echo "== extend image by 1 cluster =="
+fallocate -xl $((file_size + CLUSTER_SIZE)) "$TEST_IMG"
+
+file_size=`stat --printf="%s" "$TEST_IMG"`
+echo "file size: $file_size"
+
+echo "== repair image =="
+_check_test_img -r all
+
+file_size=`stat --printf="%s" "$TEST_IMG"`
+echo "file size: $file_size"
+
+echo "== check last cluster =="
+{ $QEMU_IO -c "read -P 0x11 $LAST_CLUSTER_OFF $CLUSTER_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+# Clear image
+_make_test_img $SIZE
+
+echo "== TEST DUPLICATION CHECK =="
+
+echo "== write pattern to whole image =="
+{ $QEMU_IO -c "write -P 0x11 0 $SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+echo "== write another pattern to second cluster =="
+{ $QEMU_IO -c "write -P 0x55 $CLUSTER_SIZE $CLUSTER_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+echo "== check second cluster =="
+{ $QEMU_IO -c "read -P 0x55 $CLUSTER_SIZE $CLUSTER_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+echo "== corrupt image =="
+poke_file "$TEST_IMG" "$(($BAT_OFFSET + 4))" "\x01\x00\x00\x00"
+
+echo "== check second cluster =="
+{ $QEMU_IO -c "read -P 0x11 $CLUSTER_SIZE $CLUSTER_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+echo "== repair image =="
+_check_test_img -r all
+
+echo "== check second cluster =="
+{ $QEMU_IO -c "read -P 0x11 $CLUSTER_SIZE $CLUSTER_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+echo "== check first cluster on host =="
+printf "content: 0x%02x\n" `peek_file_le $TEST_IMG $(($CLUSTER_SIZE)) 1`
+
+echo "== check second cluster on host =="
+printf "content: 0x%02x\n" `peek_file_le $TEST_IMG $(($CLUSTER_SIZE)) 1`
+
+# Clear image
+_make_test_img $SIZE
+
+echo "== TEST DATA_OFF CHECK =="
+
+echo "== write pattern to first cluster =="
+{ $QEMU_IO -c "write -P 0x55 0 $CLUSTER_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+echo "== spoil data_off field =="
+poke_file "$TEST_IMG" "$DATA_OFF_OFFSET" "\xff\xff\xff\xff"
+
+echo "== check first cluster =="
+{ $QEMU_IO -c "read -P 0x55 0 $CLUSTER_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/tests/parallels-checks.out b/tests/qemu-iotests/tests/parallels-checks.out
new file mode 100644
index 0000000000..98a3a7f55e
--- /dev/null
+++ b/tests/qemu-iotests/tests/parallels-checks.out
@@ -0,0 +1,75 @@
+QA output created by parallels-checks
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4194304
+== TEST OUT OF IMAGE CHECK ==
+== write pattern ==
+wrote 4194304/4194304 bytes at offset 0
+4 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+== corrupt image ==
+== read corrupted image with repairing ==
+Repairing cluster 0 is outside image
+read 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4194304
+== TEST LEAK CHECK ==
+== write pattern to last cluster ==
+write -P 0x11 3145728 1048576
+wrote 1048576/1048576 bytes at offset 3145728
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+file size: 2097152
+== extend image by 1 cluster ==
+file size: 3145728
+== repair image ==
+Repairing space leaked at the end of the image 1048576
+The following inconsistencies were found and repaired:
+
+    1 leaked clusters
+    0 corruptions
+
+Double checking the fixed image now...
+No errors were found on the image.
+file size: 2097152
+== check last cluster ==
+read 1048576/1048576 bytes at offset 3145728
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4194304
+== TEST DUPLICATION CHECK ==
+== write pattern to whole image ==
+wrote 4194304/4194304 bytes at offset 0
+4 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+== write another pattern to second cluster ==
+wrote 1048576/1048576 bytes at offset 1048576
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+== check second cluster ==
+read 1048576/1048576 bytes at offset 1048576
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+== corrupt image ==
+== check second cluster ==
+read 1048576/1048576 bytes at offset 1048576
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+== repair image ==
+Repairing duplicate offset in BAT entry 1
+The following inconsistencies were found and repaired:
+
+    0 leaked clusters
+    1 corruptions
+
+Double checking the fixed image now...
+No errors were found on the image.
+== check second cluster ==
+read 1048576/1048576 bytes at offset 1048576
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+== check first cluster on host ==
+content: 0x11
+== check second cluster on host ==
+content: 0x11
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4194304
+== TEST DATA_OFF CHECK ==
+== write pattern to first cluster ==
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+== spoil data_off field ==
+== check first cluster ==
+Repairing data_off field has incorrect value
+read 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+*** done