35 files changed, 210 insertions, 194 deletions

diff --git a/block.c b/block.c
index 7b557f3e04..6c6bb3ec7a 100644
--- a/block.c
+++ b/block.c
@@ -3307,7 +3307,7 @@ exit:
 /**
  * Truncate file to 'offset' bytes (needed only for file protocols)
  */
-int bdrv_truncate(BdrvChild *child, int64_t offset)
+int bdrv_truncate(BdrvChild *child, int64_t offset, Error **errp)
 {
     BlockDriverState *bs = child->bs;
     BlockDriver *drv = bs->drv;
@@ -3315,14 +3315,22 @@ int bdrv_truncate(BdrvChild *child, int64_t offset)
 
     assert(child->perm & BLK_PERM_RESIZE);
 
-    if (!drv)
+    if (!drv) {
+        error_setg(errp, "No medium inserted");
         return -ENOMEDIUM;
-    if (!drv->bdrv_truncate)
+    }
+    if (!drv->bdrv_truncate) {
+        error_setg(errp, "Image format driver does not support resize");
         return -ENOTSUP;
-    if (bs->read_only)
+    }
+    if (bs->read_only) {
+        error_setg(errp, "Image is read-only");
         return -EACCES;
+    }
+
+    assert(!(bs->open_flags & BDRV_O_INACTIVE));
 
-    ret = drv->bdrv_truncate(bs, offset);
+    ret = drv->bdrv_truncate(bs, offset, errp);
     if (ret == 0) {
         ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
         bdrv_dirty_bitmap_truncate(bs);
diff --git a/block/blkdebug.c b/block/blkdebug.c
index cc4a146e84..d2a7561c4c 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -659,9 +659,9 @@ static int64_t blkdebug_getlength(BlockDriverState *bs)
     return bdrv_getlength(bs->file->bs);
 }
 
-static int blkdebug_truncate(BlockDriverState *bs, int64_t offset)
+static int blkdebug_truncate(BlockDriverState *bs, int64_t offset, Error **errp)
 {
-    return bdrv_truncate(bs->file, offset);
+    return bdrv_truncate(bs->file, offset, errp);
 }
 
 static void blkdebug_refresh_filename(BlockDriverState *bs, QDict *options)
diff --git a/block/block-backend.c b/block/block-backend.c
index ae3d7713ce..f5bf13eec9 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1746,13 +1746,14 @@ int blk_pwrite_compressed(BlockBackend *blk, int64_t offset, const void *buf,
                    BDRV_REQ_WRITE_COMPRESSED);
 }
 
-int blk_truncate(BlockBackend *blk, int64_t offset)
+int blk_truncate(BlockBackend *blk, int64_t offset, Error **errp)
 {
     if (!blk_is_available(blk)) {
+        error_setg(errp, "No medium inserted");
         return -ENOMEDIUM;
     }
 
-    return bdrv_truncate(blk->root, offset);
+    return bdrv_truncate(blk->root, offset, errp);
 }
 
 static void blk_pdiscard_entry(void *opaque)
diff --git a/block/commit.c b/block/commit.c
index 91d2c344f6..76a0d98c6f 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -151,7 +151,7 @@ static void coroutine_fn commit_run(void *opaque)
     }
 
     if (base_len < s->common.len) {
-        ret = blk_truncate(s->base, s->common.len);
+        ret = blk_truncate(s->base, s->common.len, NULL);
         if (ret) {
             goto out;
         }
@@ -511,8 +511,9 @@ int bdrv_commit(BlockDriverState *bs)
      * grow the backing file image if possible.  If not possible,
      * we must return an error */
     if (length > backing_length) {
-        ret = blk_truncate(backing, length);
+        ret = blk_truncate(backing, length, &local_err);
         if (ret < 0) {
+            error_report_err(local_err);
             goto ro_cleanup;
         }
     }
diff --git a/block/crypto.c b/block/crypto.c
index 34549b28a5..6828180840 100644
--- a/block/crypto.c
+++ b/block/crypto.c
@@ -381,7 +381,8 @@ static int block_crypto_create_generic(QCryptoBlockFormat format,
     return ret;
 }
 
-static int block_crypto_truncate(BlockDriverState *bs, int64_t offset)
+static int block_crypto_truncate(BlockDriverState *bs, int64_t offset,
+                                 Error **errp)
 {
     BlockCrypto *crypto = bs->opaque;
     size_t payload_offset =
@@ -389,7 +390,7 @@ static int block_crypto_truncate(BlockDriverState *bs, int64_t offset)
 
     offset += payload_offset;
 
-    return bdrv_truncate(bs->file, offset);
+    return bdrv_truncate(bs->file, offset, errp);
 }
 
 static void block_crypto_close(BlockDriverState *bs)
diff --git a/block/file-posix.c b/block/file-posix.c
index ade71db0e2..1941fb6749 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -1407,24 +1407,31 @@ static void raw_close(BlockDriverState *bs)
     }
 }
 
-static int raw_truncate(BlockDriverState *bs, int64_t offset)
+static int raw_truncate(BlockDriverState *bs, int64_t offset, Error **errp)
 {
     BDRVRawState *s = bs->opaque;
     struct stat st;
+    int ret;
 
     if (fstat(s->fd, &st)) {
-        return -errno;
+        ret = -errno;
+        error_setg_errno(errp, -ret, "Failed to fstat() the file");
+        return ret;
     }
 
     if (S_ISREG(st.st_mode)) {
         if (ftruncate(s->fd, offset) < 0) {
-            return -errno;
+            ret = -errno;
+            error_setg_errno(errp, -ret, "Failed to resize the file");
+            return ret;
         }
     } else if (S_ISCHR(st.st_mode) || S_ISBLK(st.st_mode)) {
-       if (offset > raw_getlength(bs)) {
-           return -EINVAL;
-       }
+        if (offset > raw_getlength(bs)) {
+            error_setg(errp, "Cannot grow device files");
+            return -EINVAL;
+        }
     } else {
+        error_setg(errp, "Resizing this file is not supported");
         return -ENOTSUP;
     }
 
diff --git a/block/file-win32.c b/block/file-win32.c
index e132ba17da..7872e00a21 100644
--- a/block/file-win32.c
+++ b/block/file-win32.c
@@ -460,7 +460,7 @@ static void raw_close(BlockDriverState *bs)
     }
 }
 
-static int raw_truncate(BlockDriverState *bs, int64_t offset)
+static int raw_truncate(BlockDriverState *bs, int64_t offset, Error **errp)
 {
     BDRVRawState *s = bs->opaque;
     LONG low, high;
@@ -475,11 +475,11 @@ static int raw_truncate(BlockDriverState *bs, int64_t offset)
      */
     dwPtrLow = SetFilePointer(s->hfile, low, &high, FILE_BEGIN);
     if (dwPtrLow == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR) {
-        fprintf(stderr, "SetFilePointer error: %lu\n", GetLastError());
+        error_setg_win32(errp, GetLastError(), "SetFilePointer error");
         return -EIO;
     }
     if (SetEndOfFile(s->hfile) == 0) {
-        fprintf(stderr, "SetEndOfFile error: %lu\n", GetLastError());
+        error_setg_win32(errp, GetLastError(), "SetEndOfFile error");
         return -EIO;
     }
     return 0;
diff --git a/block/gluster.c b/block/gluster.c
index cf29b5f9a4..1d4e2f7c52 100644
--- a/block/gluster.c
+++ b/block/gluster.c
@@ -1092,14 +1092,17 @@ static coroutine_fn int qemu_gluster_co_rw(BlockDriverState *bs,
     return acb.ret;
 }
 
-static int qemu_gluster_truncate(BlockDriverState *bs, int64_t offset)
+static int qemu_gluster_truncate(BlockDriverState *bs, int64_t offset,
+                                 Error **errp)
 {
     int ret;
     BDRVGlusterState *s = bs->opaque;
 
     ret = glfs_ftruncate(s->fd, offset);
     if (ret < 0) {
-        return -errno;
+        ret = -errno;
+        error_setg_errno(errp, -ret, "Failed to truncate file");
+        return ret;
     }
 
     return 0;
diff --git a/block/iscsi.c b/block/iscsi.c
index 42fb0b019c..5daa201181 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -2059,22 +2059,24 @@ static void iscsi_reopen_commit(BDRVReopenState *reopen_state)
     }
 }
 
-static int iscsi_truncate(BlockDriverState *bs, int64_t offset)
+static int iscsi_truncate(BlockDriverState *bs, int64_t offset, Error **errp)
 {
     IscsiLun *iscsilun = bs->opaque;
     Error *local_err = NULL;
 
     if (iscsilun->type != TYPE_DISK) {
+        error_setg(errp, "Cannot resize non-disk iSCSI devices");
         return -ENOTSUP;
     }
 
     iscsi_readcapacity_sync(iscsilun, &local_err);
     if (local_err != NULL) {
-        error_free(local_err);
+        error_propagate(errp, local_err);
         return -EIO;
     }
 
     if (offset > iscsi_getlength(bs)) {
+        error_setg(errp, "Cannot grow iSCSI devices");
         return -EINVAL;
     }
 
diff --git a/block/mirror.c b/block/mirror.c
index 9f5eb692fd..e86f8f8ad7 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -724,7 +724,7 @@ static void coroutine_fn mirror_run(void *opaque)
         }
 
         if (s->bdev_length > base_length) {
-            ret = blk_truncate(s->target, s->bdev_length);
+            ret = blk_truncate(s->target, s->bdev_length, NULL);
             if (ret < 0) {
                 goto immediate_exit;
             }
diff --git a/block/nfs.c b/block/nfs.c
index 6541dec1fc..76572ae546 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -764,10 +764,18 @@ static int64_t nfs_get_allocated_file_size(BlockDriverState *bs)
     return (task.ret < 0 ? task.ret : st.st_blocks * 512);
 }
 
-static int nfs_file_truncate(BlockDriverState *bs, int64_t offset)
+static int nfs_file_truncate(BlockDriverState *bs, int64_t offset, Error **errp)
 {
     NFSClient *client = bs->opaque;
-    return nfs_ftruncate(client->context, client->fh, offset);
+    int ret;
+
+    ret = nfs_ftruncate(client->context, client->fh, offset);
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "Failed to truncate file");
+        return ret;
+    }
+
+    return 0;
 }
 
 /* Note that this will not re-establish a connection with the NFS server
diff --git a/block/parallels.c b/block/parallels.c
index 90acf79687..8be46a7d48 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -223,7 +223,8 @@ static int64_t allocate_clusters(BlockDriverState *bs, int64_t sector_num,
                                      space << BDRV_SECTOR_BITS, 0);
         } else {
             ret = bdrv_truncate(bs->file,
-                                (s->data_end + space) << BDRV_SECTOR_BITS);
+                                (s->data_end + space) << BDRV_SECTOR_BITS,
+                                NULL);
         }
         if (ret < 0) {
             return ret;
@@ -456,8 +457,10 @@ static int parallels_check(BlockDriverState *bs, BdrvCheckResult *res,
                 size - res->image_end_offset);
         res->leaks += count;
         if (fix & BDRV_FIX_LEAKS) {
-            ret = bdrv_truncate(bs->file, res->image_end_offset);
+            Error *local_err = NULL;
+            ret = bdrv_truncate(bs->file, res->image_end_offset, &local_err);
             if (ret < 0) {
+                error_report_err(local_err);
                 res->check_errors++;
                 return ret;
             }
@@ -504,7 +507,7 @@ static int parallels_create(const char *filename, QemuOpts *opts, Error **errp)
 
     blk_set_allow_write_beyond_eof(file, true);
 
-    ret = blk_truncate(file, 0);
+    ret = blk_truncate(file, 0, errp);
     if (ret < 0) {
         goto exit;
     }
@@ -696,7 +699,7 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     if (!(flags & BDRV_O_RESIZE) || !bdrv_has_zero_init(bs->file->bs) ||
-            bdrv_truncate(bs->file, bdrv_getlength(bs->file->bs)) != 0) {
+            bdrv_truncate(bs->file, bdrv_getlength(bs->file->bs), NULL) != 0) {
         s->prealloc_mode = PRL_PREALLOC_MODE_FALLOCATE;
     }
 
@@ -739,7 +742,7 @@ static void parallels_close(BlockDriverState *bs)
     }
 
     if (bs->open_flags & BDRV_O_RDWR) {
-        bdrv_truncate(bs->file, s->data_end << BDRV_SECTOR_BITS);
+        bdrv_truncate(bs->file, s->data_end << BDRV_SECTOR_BITS, NULL);
     }
 
     g_free(s->bat_dirty_bmap);
diff --git a/block/qcow.c b/block/qcow.c
index 9d6ac83959..5d147b962e 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -473,7 +473,7 @@ static uint64_t get_cluster_offset(BlockDriverState *bs,
                 /* round to cluster size */
                 cluster_offset = (cluster_offset + s->cluster_size - 1) &
                     ~(s->cluster_size - 1);
-                bdrv_truncate(bs->file, cluster_offset + s->cluster_size);
+                bdrv_truncate(bs->file, cluster_offset + s->cluster_size, NULL);
                 /* if encrypted, we must initialize the cluster
                    content which won't be written */
                 if (bs->encrypted &&
@@ -833,7 +833,7 @@ static int qcow_create(const char *filename, QemuOpts *opts, Error **errp)
 
     blk_set_allow_write_beyond_eof(qcow_blk, true);
 
-    ret = blk_truncate(qcow_blk, 0);
+    ret = blk_truncate(qcow_blk, 0, errp);
     if (ret < 0) {
         goto exit;
     }
@@ -916,7 +916,7 @@ static int qcow_make_empty(BlockDriverState *bs)
     if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table,
             l1_length) < 0)
         return -1;
-    ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length);
+    ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, NULL);
     if (ret < 0)
         return ret;
 
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 9e96f64c8b..4efca7ebdb 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -1728,14 +1728,17 @@ static int check_refblocks(BlockDriverState *bs, BdrvCheckResult *res,
 
             if (fix & BDRV_FIX_ERRORS) {
                 int64_t new_nb_clusters;
+                Error *local_err = NULL;
 
                 if (offset > INT64_MAX - s->cluster_size) {
                     ret = -EINVAL;
                     goto resize_fail;
                 }
 
-                ret = bdrv_truncate(bs->file, offset + s->cluster_size);
+                ret = bdrv_truncate(bs->file, offset + s->cluster_size,
+                                    &local_err);
                 if (ret < 0) {
+                    error_report_err(local_err);
                     goto resize_fail;
                 }
                 size = bdrv_getlength(bs->file->bs);
diff --git a/block/qcow2.c b/block/qcow2.c
index 6a92d2ef3f..5c1573c999 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2294,9 +2294,9 @@ static int qcow2_create2(const char *filename, int64_t total_size,
     }
 
     /* Okay, now that we have a valid image, let's give it the right size */
-    ret = blk_truncate(blk, total_size);
+    ret = blk_truncate(blk, total_size, errp);
     if (ret < 0) {
-        error_setg_errno(errp, -ret, "Could not resize image");
+        error_prepend(errp, "Could not resize image: ");
         goto out;
     }
 
@@ -2515,7 +2515,12 @@ static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs,
 
     if (!QEMU_IS_ALIGNED(offset | count, s->cluster_size)) {
         assert(count < s->cluster_size);
-        return -ENOTSUP;
+        /* Ignore partial clusters, except for the special case of the
+         * complete partial cluster at the end of an unaligned file */
+        if (!QEMU_IS_ALIGNED(offset, s->cluster_size) ||
+            offset + count != bs->total_sectors * BDRV_SECTOR_SIZE) {
+            return -ENOTSUP;
+        }
     }
 
     qemu_co_mutex_lock(&s->lock);
@@ -2525,32 +2530,33 @@ static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs,
     return ret;
 }
 
-static int qcow2_truncate(BlockDriverState *bs, int64_t offset)
+static int qcow2_truncate(BlockDriverState *bs, int64_t offset, Error **errp)
 {
     BDRVQcow2State *s = bs->opaque;
     int64_t new_l1_size;
     int ret;
 
     if (offset & 511) {
-        error_report("The new size must be a multiple of 512");
+        error_setg(errp, "The new size must be a multiple of 512");
         return -EINVAL;
     }
 
     /* cannot proceed if image has snapshots */
     if (s->nb_snapshots) {
-        error_report("Can't resize an image which has snapshots");
+        error_setg(errp, "Can't resize an image which has snapshots");
         return -ENOTSUP;
     }
 
     /* shrinking is currently not supported */
     if (offset < bs->total_sectors * 512) {
-        error_report("qcow2 doesn't support shrinking images yet");
+        error_setg(errp, "qcow2 doesn't support shrinking images yet");
         return -ENOTSUP;
     }
 
     new_l1_size = size_to_l1(s, offset);
     ret = qcow2_grow_l1_table(bs, new_l1_size, true);
     if (ret < 0) {
+        error_setg_errno(errp, -ret, "Failed to grow the L1 table");
         return ret;
     }
 
@@ -2559,6 +2565,7 @@ static int qcow2_truncate(BlockDriverState *bs, int64_t offset)
     ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, size),
                            &offset, sizeof(uint64_t));
     if (ret < 0) {
+        error_setg_errno(errp, -ret, "Failed to update the image size");
         return ret;
     }
 
@@ -2584,7 +2591,7 @@ qcow2_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
         /* align end of file to a sector boundary to ease reading with
            sector based I/Os */
         cluster_offset = bdrv_getlength(bs->file->bs);
-        return bdrv_truncate(bs->file, cluster_offset);
+        return bdrv_truncate(bs->file, cluster_offset, NULL);
     }
 
     buf = qemu_blockalign(bs, s->cluster_size);
@@ -2674,6 +2681,7 @@ fail:
 static int make_completely_empty(BlockDriverState *bs)
 {
     BDRVQcow2State *s = bs->opaque;
+    Error *local_err = NULL;
     int ret, l1_clusters;
     int64_t offset;
     uint64_t *new_reftable = NULL;
@@ -2798,8 +2806,10 @@ static int make_completely_empty(BlockDriverState *bs)
         goto fail;
     }
 
-    ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size);
+    ret = bdrv_truncate(bs->file, (3 + l1_clusters) * s->cluster_size,
+                        &local_err);
     if (ret < 0) {
+        error_report_err(local_err);
         goto fail;
     }
 
@@ -3273,9 +3283,10 @@ static int qcow2_amend_options(BlockDriverState *bs, QemuOpts *opts,
             return ret;
         }
 
-        ret = blk_truncate(blk, new_size);
+        ret = blk_truncate(blk, new_size, &local_err);
         blk_unref(blk);
         if (ret < 0) {
+            error_report_err(local_err);
             return ret;
         }
     }
diff --git a/block/qed.c b/block/qed.c
index 5ec7fd83f2..fd76817cbb 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -635,7 +635,7 @@ static int qed_create(const char *filename, uint32_t cluster_size,
     blk_set_allow_write_beyond_eof(blk, true);
 
     /* File must start empty and grow, check truncate is supported */
-    ret = blk_truncate(blk, 0);
+    ret = blk_truncate(blk, 0, errp);
     if (ret < 0) {
         goto out;
     }
@@ -1518,7 +1518,7 @@ static int coroutine_fn bdrv_qed_co_pwrite_zeroes(BlockDriverState *bs,
     return cb.ret;
 }
 
-static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset)
+static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset, Error **errp)
 {
     BDRVQEDState *s = bs->opaque;
     uint64_t old_image_size;
@@ -1526,11 +1526,12 @@ static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset)
 
     if (!qed_is_image_size_valid(offset, s->header.cluster_size,
                                  s->header.table_size)) {
+        error_setg(errp, "Invalid image size specified");
         return -EINVAL;
     }
 
-    /* Shrinking is currently not supported */
     if ((uint64_t)offset < s->header.image_size) {
+        error_setg(errp, "Shrinking images is currently not supported");
         return -ENOTSUP;
     }
 
@@ -1539,6 +1540,7 @@ static int bdrv_qed_truncate(BlockDriverState *bs, int64_t offset)
     ret = qed_write_header_sync(s);
     if (ret < 0) {
         s->header.image_size = old_image_size;
+        error_setg_errno(errp, -ret, "Failed to update the image size");
     }
     return ret;
 }
diff --git a/block/raw-format.c b/block/raw-format.c
index 86fbc657eb..36e65036f0 100644
--- a/block/raw-format.c
+++ b/block/raw-format.c
@@ -327,21 +327,23 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp)
     }
 }
 
-static int raw_truncate(BlockDriverState *bs, int64_t offset)
+static int raw_truncate(BlockDriverState *bs, int64_t offset, Error **errp)
 {
     BDRVRawState *s = bs->opaque;
 
     if (s->has_size) {
+        error_setg(errp, "Cannot resize fixed-size raw disks");
         return -ENOTSUP;
     }
 
     if (INT64_MAX - offset < s->offset) {
+        error_setg(errp, "Disk size too large for the chosen offset");
         return -EINVAL;
     }
 
     s->size = offset;
     offset += s->offset;
-    return bdrv_truncate(bs->file, offset);
+    return bdrv_truncate(bs->file, offset, errp);
 }
 
 static int raw_media_changed(BlockDriverState *bs)
diff --git a/block/rbd.c b/block/rbd.c
index 6471f4fd2b..fbf30591d1 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -916,13 +916,14 @@ static int64_t qemu_rbd_getlength(BlockDriverState *bs)
     return info.size;
 }
 
-static int qemu_rbd_truncate(BlockDriverState *bs, int64_t offset)
+static int qemu_rbd_truncate(BlockDriverState *bs, int64_t offset, Error **errp)
 {
     BDRVRBDState *s = bs->opaque;
     int r;
 
     r = rbd_resize(s->image, offset);
     if (r < 0) {
+        error_setg_errno(errp, -r, "Failed to resize file");
         return r;
     }
 
diff --git a/block/sheepdog.c b/block/sheepdog.c
index b2a5998188..fe8fd923d5 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -2159,9 +2159,8 @@ static int64_t sd_getlength(BlockDriverState *bs)
     return s->inode.vdi_size;
 }
 
-static int sd_truncate(BlockDriverState *bs, int64_t offset)
+static int sd_truncate(BlockDriverState *bs, int64_t offset, Error **errp)
 {
-    Error *local_err = NULL;
     BDRVSheepdogState *s = bs->opaque;
     int ret, fd;
     unsigned int datalen;
@@ -2169,16 +2168,15 @@ static int sd_truncate(BlockDriverState *bs, int64_t offset)
 
     max_vdi_size = (UINT64_C(1) << s->inode.block_size_shift) * MAX_DATA_OBJS;
     if (offset < s->inode.vdi_size) {
-        error_report("shrinking is not supported");
+        error_setg(errp, "shrinking is not supported");
         return -EINVAL;
     } else if (offset > max_vdi_size) {
-        error_report("too big image size");
+        error_setg(errp, "too big image size");
         return -EINVAL;
     }
 
-    fd = connect_to_sdog(s, &local_err);
+    fd = connect_to_sdog(s, errp);
     if (fd < 0) {
-        error_report_err(local_err);
         return fd;
     }
 
@@ -2191,7 +2189,7 @@ static int sd_truncate(BlockDriverState *bs, int64_t offset)
     close(fd);
 
     if (ret < 0) {
-        error_report("failed to update an inode.");
+        error_setg_errno(errp, -ret, "failed to update an inode");
     }
 
     return ret;
@@ -2456,7 +2454,7 @@ static coroutine_fn int sd_co_writev(BlockDriverState *bs, int64_t sector_num,
     BDRVSheepdogState *s = bs->opaque;
 
     if (offset > s->inode.vdi_size) {
-        ret = sd_truncate(bs, offset);
+        ret = sd_truncate(bs, offset, NULL);
         if (ret < 0) {
             return ret;
         }
diff --git a/block/vdi.c b/block/vdi.c
index 9b4f70e977..d12d9cdc79 100644
--- a/block/vdi.c
+++ b/block/vdi.c
@@ -832,9 +832,9 @@ static int vdi_create(const char *filename, QemuOpts *opts, Error **errp)
     }
 
     if (image_type == VDI_TYPE_STATIC) {
-        ret = blk_truncate(blk, offset + blocks * block_size);
+        ret = blk_truncate(blk, offset + blocks * block_size, errp);
         if (ret < 0) {
-            error_setg(errp, "Failed to statically allocate %s", filename);
+            error_prepend(errp, "Failed to statically allocate %s", filename);
             goto exit;
         }
     }
diff --git a/block/vhdx-log.c b/block/vhdx-log.c
index 67a91c0de5..3f4c2aa095 100644
--- a/block/vhdx-log.c
+++ b/block/vhdx-log.c
@@ -548,7 +548,7 @@ static int vhdx_log_flush(BlockDriverState *bs, BDRVVHDXState *s,
             if (new_file_size % (1024*1024)) {
                 /* round up to nearest 1MB boundary */
                 new_file_size = ((new_file_size >> 20) + 1) << 20;
-                bdrv_truncate(bs->file, new_file_size);
+                bdrv_truncate(bs->file, new_file_size, NULL);
             }
         }
         qemu_vfree(desc_entries);
diff --git a/block/vhdx.c b/block/vhdx.c
index 052a753159..e8fe3fb5e9 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -1171,7 +1171,7 @@ static int vhdx_allocate_block(BlockDriverState *bs, BDRVVHDXState *s,
     /* per the spec, the address for a block is in units of 1MB */
     *new_offset = ROUND_UP(*new_offset, 1024 * 1024);
 
-    return bdrv_truncate(bs->file, *new_offset + s->block_size);
+    return bdrv_truncate(bs->file, *new_offset + s->block_size, NULL);
 }
 
 /*
@@ -1586,7 +1586,7 @@ exit:
 static int vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
                            uint64_t image_size, VHDXImageType type,
                            bool use_zero_blocks, uint64_t file_offset,
-                           uint32_t length)
+                           uint32_t length, Error **errp)
 {
     int ret = 0;
     uint64_t data_file_offset;
@@ -1607,16 +1607,17 @@ static int vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
     if (type == VHDX_TYPE_DYNAMIC) {
         /* All zeroes, so we can just extend the file - the end of the BAT
          * is the furthest thing we have written yet */
-        ret = blk_truncate(blk, data_file_offset);
+        ret = blk_truncate(blk, data_file_offset, errp);
         if (ret < 0) {
             goto exit;
         }
     } else if (type == VHDX_TYPE_FIXED) {
-        ret = blk_truncate(blk, data_file_offset + image_size);
+        ret = blk_truncate(blk, data_file_offset + image_size, errp);
         if (ret < 0) {
             goto exit;
         }
     } else {
+        error_setg(errp, "Unsupported image type");
         ret = -ENOTSUP;
         goto exit;
     }
@@ -1627,6 +1628,7 @@ static int vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
         /* for a fixed file, the default BAT entry is not zero */
         s->bat = g_try_malloc0(length);
         if (length && s->bat == NULL) {
+            error_setg(errp, "Failed to allocate memory for the BAT");
             ret = -ENOMEM;
             goto exit;
         }
@@ -1646,6 +1648,7 @@ static int vhdx_create_bat(BlockBackend *blk, BDRVVHDXState *s,
         }
         ret = blk_pwrite(blk, file_offset, s->bat, length, 0);
         if (ret < 0) {
+            error_setg_errno(errp, -ret, "Failed to write the BAT");
             goto exit;
         }
     }
@@ -1671,7 +1674,8 @@ static int vhdx_create_new_region_table(BlockBackend *blk,
                                         uint32_t log_size,
                                         bool use_zero_blocks,
                                         VHDXImageType type,
-                                        uint64_t *metadata_offset)
+                                        uint64_t *metadata_offset,
+                                        Error **errp)
 {
     int ret = 0;
     uint32_t offset = 0;
@@ -1740,7 +1744,7 @@ static int vhdx_create_new_region_table(BlockBackend *blk,
     /* The region table gives us the data we need to create the BAT,
      * so do that now */
     ret = vhdx_create_bat(blk, s, image_size, type, use_zero_blocks,
-                          bat_file_offset, bat_length);
+                          bat_file_offset, bat_length, errp);
     if (ret < 0) {
         goto exit;
     }
@@ -1749,12 +1753,14 @@ static int vhdx_create_new_region_table(BlockBackend *blk,
     ret = blk_pwrite(blk, VHDX_REGION_TABLE_OFFSET, buffer,
                      VHDX_HEADER_BLOCK_SIZE, 0);
     if (ret < 0) {
+        error_setg_errno(errp, -ret, "Failed to write first region table");
         goto exit;
     }
 
     ret = blk_pwrite(blk, VHDX_REGION_TABLE2_OFFSET, buffer,
                      VHDX_HEADER_BLOCK_SIZE, 0);
     if (ret < 0) {
+        error_setg_errno(errp, -ret, "Failed to write second region table");
         goto exit;
     }
 
@@ -1825,6 +1831,7 @@ static int vhdx_create(const char *filename, QemuOpts *opts, Error **errp)
         ret = -ENOTSUP;
         goto exit;
     } else {
+        error_setg(errp, "Invalid subformat '%s'", type);
         ret = -EINVAL;
         goto exit;
     }
@@ -1879,12 +1886,14 @@ static int vhdx_create(const char *filename, QemuOpts *opts, Error **errp)
     ret = blk_pwrite(blk, VHDX_FILE_ID_OFFSET, &signature, sizeof(signature),
                      0);
     if (ret < 0) {
+        error_setg_errno(errp, -ret, "Failed to write file signature");
         goto delete_and_exit;
     }
     if (creator) {
         ret = blk_pwrite(blk, VHDX_FILE_ID_OFFSET + sizeof(signature),
                          creator, creator_items * sizeof(gunichar2), 0);
         if (ret < 0) {
+            error_setg_errno(errp, -ret, "Failed to write creator field");
             goto delete_and_exit;
         }
     }
@@ -1893,13 +1902,14 @@ static int vhdx_create(const char *filename, QemuOpts *opts, Error **errp)
     /* Creates (B),(C) */
     ret = vhdx_create_new_headers(blk, image_size, log_size);
     if (ret < 0) {
+        error_setg_errno(errp, -ret, "Failed to write image headers");
         goto delete_and_exit;
     }
 
     /* Creates (D),(E),(G) explicitly. (F) created as by-product */
     ret = vhdx_create_new_region_table(blk, image_size, block_size, 512,
                                        log_size, use_zero_blocks, image_type,
-                                       &metadata_offset);
+                                       &metadata_offset, errp);
     if (ret < 0) {
         goto delete_and_exit;
     }
@@ -1908,6 +1918,7 @@ static int vhdx_create(const char *filename, QemuOpts *opts, Error **errp)
     ret = vhdx_create_new_metadata(blk, image_size, block_size, 512,
                                    metadata_offset, image_type);
     if (ret < 0) {
+        error_setg_errno(errp, -ret, "Failed to initialize metadata");
         goto delete_and_exit;
     }
 
diff --git a/block/vmdk.c b/block/vmdk.c
index a9bd22bf93..c61b9cc8e0 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -1714,10 +1714,7 @@ static int vmdk_create_extent(const char *filename, int64_t filesize,
     blk_set_allow_write_beyond_eof(blk, true);
 
     if (flat) {
-        ret = blk_truncate(blk, filesize);
-        if (ret < 0) {
-            error_setg_errno(errp, -ret, "Could not truncate file");
-        }
+        ret = blk_truncate(blk, filesize, errp);
         goto exit;
     }
     magic = cpu_to_be32(VMDK4_MAGIC);
@@ -1780,9 +1777,8 @@ static int vmdk_create_extent(const char *filename, int64_t filesize,
         goto exit;
     }
 
-    ret = blk_truncate(blk, le64_to_cpu(header.grain_offset) << 9);
+    ret = blk_truncate(blk, le64_to_cpu(header.grain_offset) << 9, errp);
     if (ret < 0) {
-        error_setg_errno(errp, -ret, "Could not truncate file");
         goto exit;
     }
 
@@ -2090,10 +2086,7 @@ static int vmdk_create(const char *filename, QemuOpts *opts, Error **errp)
     /* bdrv_pwrite write padding zeros to align to sector, we don't need that
      * for description file */
     if (desc_offset == 0) {
-        ret = blk_truncate(new_blk, desc_len);
-        if (ret < 0) {
-            error_setg_errno(errp, -ret, "Could not truncate file");
-        }
+        ret = blk_truncate(new_blk, desc_len, errp);
     }
 exit:
     if (new_blk) {
diff --git a/block/vpc.c b/block/vpc.c
index f591d4be38..ecfee77149 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -851,20 +851,21 @@ static int create_dynamic_disk(BlockBackend *blk, uint8_t *buf,
 }
 
 static int create_fixed_disk(BlockBackend *blk, uint8_t *buf,
-                             int64_t total_size)
+                             int64_t total_size, Error **errp)
 {
     int ret;
 
     /* Add footer to total size */
     total_size += HEADER_SIZE;
 
-    ret = blk_truncate(blk, total_size);
+    ret = blk_truncate(blk, total_size, errp);
     if (ret < 0) {
         return ret;
     }
 
     ret = blk_pwrite(blk, total_size - HEADER_SIZE, buf, HEADER_SIZE, 0);
     if (ret < 0) {
+        error_setg_errno(errp, -ret, "Unable to write VHD header");
         return ret;
     }
 
@@ -996,11 +997,11 @@ static int vpc_create(const char *filename, QemuOpts *opts, Error **errp)
 
     if (disk_type == VHD_DYNAMIC) {
         ret = create_dynamic_disk(blk, buf, total_sectors);
+        if (ret < 0) {
+            error_setg(errp, "Unable to create or write VHD header");
+        }
     } else {
-        ret = create_fixed_disk(blk, buf, total_size);
-    }
-    if (ret < 0) {
-        error_setg(errp, "Unable to create or write VHD header");
+        ret = create_fixed_disk(blk, buf, total_size, errp);
     }
 
 out:
diff --git a/blockdev.c b/blockdev.c
index 64282065d8..4d8cdedd54 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2930,26 +2930,7 @@ void qmp_block_resize(bool has_device, const char *device,
     /* complete all in-flight operations before resizing the device */
     bdrv_drain_all();
 
-    ret = blk_truncate(blk, size);
-    switch (ret) {
-    case 0:
-        break;
-    case -ENOMEDIUM:
-        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
-        break;
-    case -ENOTSUP:
-        error_setg(errp, QERR_UNSUPPORTED);
-        break;
-    case -EACCES:
-        error_setg(errp, "Device '%s' is read only", device);
-        break;
-    case -EBUSY:
-        error_setg(errp, QERR_DEVICE_IN_USE, device);
-        break;
-    default:
-        error_setg_errno(errp, -ret, "Could not resize");
-        break;
-    }
+    ret = blk_truncate(blk, size, errp);
 
 out:
     blk_unref(blk);
diff --git a/include/block/block.h b/include/block/block.h
index 144df0ddfb..862eb56fc7 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -294,7 +294,7 @@ BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
     const char *backing_file);
 int bdrv_get_backing_file_depth(BlockDriverState *bs);
 void bdrv_refresh_filename(BlockDriverState *bs);
-int bdrv_truncate(BdrvChild *child, int64_t offset);
+int bdrv_truncate(BdrvChild *child, int64_t offset, Error **errp);
 int64_t bdrv_nb_sectors(BlockDriverState *bs);
 int64_t bdrv_getlength(BlockDriverState *bs);
 int64_t bdrv_get_allocated_file_size(BlockDriverState *bs);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 4f8cd29ae4..87739405d5 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -196,7 +196,7 @@ struct BlockDriver {
     int coroutine_fn (*bdrv_co_flush_to_os)(BlockDriverState *bs);
 
     const char *protocol_name;
-    int (*bdrv_truncate)(BlockDriverState *bs, int64_t offset);
+    int (*bdrv_truncate)(BlockDriverState *bs, int64_t offset, Error **errp);
 
     int64_t (*bdrv_getlength)(BlockDriverState *bs);
     bool has_variable_length;
@@ -252,7 +252,7 @@ struct BlockDriver {
      * Returns 0 for completed check, -errno for internal errors.
      * The check results are stored in result.
      */
-    int (*bdrv_check)(BlockDriverState* bs, BdrvCheckResult *result,
+    int (*bdrv_check)(BlockDriverState *bs, BdrvCheckResult *result,
         BdrvCheckMode fix);
 
     int (*bdrv_amend_options)(BlockDriverState *bs, QemuOpts *opts,
@@ -454,13 +454,13 @@ struct BdrvChildRole {
     /* Returns a name that is supposedly more useful for human users than the
      * node name for identifying the node in question (in particular, a BB
      * name), or NULL if the parent can't provide a better name. */
-    const char* (*get_name)(BdrvChild *child);
+    const char *(*get_name)(BdrvChild *child);
 
     /* Returns a malloced string that describes the parent of the child for a
      * human reader. This could be a node-name, BlockBackend name, qdev ID or
      * QOM path of the device owning the BlockBackend, job type and ID etc. The
      * caller is responsible for freeing the memory. */
-    char* (*get_parent_desc)(BdrvChild *child);
+    char *(*get_parent_desc)(BdrvChild *child);
 
     /*
      * If this pair of functions is implemented, the parent doesn't issue new
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 133e542f20..840ad6134c 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -225,7 +225,7 @@ int coroutine_fn blk_co_pwrite_zeroes(BlockBackend *blk, int64_t offset,
                                       int count, BdrvRequestFlags flags);
 int blk_pwrite_compressed(BlockBackend *blk, int64_t offset, const void *buf,
                           int count);
-int blk_truncate(BlockBackend *blk, int64_t offset);
+int blk_truncate(BlockBackend *blk, int64_t offset, Error **errp);
 int blk_pdiscard(BlockBackend *blk, int64_t offset, int count);
 int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf,
                      int64_t pos, int size);
diff --git a/qemu-img.c b/qemu-img.c
index 704488484d..c7196362df 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1554,9 +1554,15 @@ static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num)
 
     if (s->sector_next_status <= sector_num) {
         BlockDriverState *file;
-        ret = bdrv_get_block_status(blk_bs(s->src[src_cur]),
-                                    sector_num - src_cur_offset,
-                                    n, &n, &file);
+        if (s->target_has_backing) {
+            ret = bdrv_get_block_status(blk_bs(s->src[src_cur]),
+                                        sector_num - src_cur_offset,
+                                        n, &n, &file);
+        } else {
+            ret = bdrv_get_block_status_above(blk_bs(s->src[src_cur]), NULL,
+                                              sector_num - src_cur_offset,
+                                              n, &n, &file);
+        }
         if (ret < 0) {
             return ret;
         }
@@ -1565,26 +1571,8 @@ static int convert_iteration_sectors(ImgConvertState *s, int64_t sector_num)
             s->status = BLK_ZERO;
         } else if (ret & BDRV_BLOCK_DATA) {
             s->status = BLK_DATA;
-        } else if (!s->target_has_backing) {
-            /* Without a target backing file we must copy over the contents of
-             * the backing file as well. */
-            /* Check block status of the backing file chain to avoid
-             * needlessly reading zeroes and limiting the iteration to the
-             * buffer size */
-            ret = bdrv_get_block_status_above(blk_bs(s->src[src_cur]), NULL,
-                                              sector_num - src_cur_offset,
-                                              n, &n, &file);
-            if (ret < 0) {
-                return ret;
-            }
-
-            if (ret & BDRV_BLOCK_ZERO) {
-                s->status = BLK_ZERO;
-            } else {
-                s->status = BLK_DATA;
-            }
         } else {
-            s->status = BLK_BACKING_FILE;
+            s->status = s->target_has_backing ? BLK_BACKING_FILE : BLK_DATA;
         }
 
         s->sector_next_status = sector_num + n;
@@ -1661,6 +1649,8 @@ static int coroutine_fn convert_co_write(ImgConvertState *s, int64_t sector_num,
 
     while (nb_sectors > 0) {
         int n = nb_sectors;
+        BdrvRequestFlags flags = s->compressed ? BDRV_REQ_WRITE_COMPRESSED : 0;
+
         switch (status) {
         case BLK_BACKING_FILE:
             /* If we have a backing file, leave clusters unallocated that are
@@ -1670,43 +1660,24 @@ static int coroutine_fn convert_co_write(ImgConvertState *s, int64_t sector_num,
             break;
 
         case BLK_DATA:
-            /* We must always write compressed clusters as a whole, so don't
-             * try to find zeroed parts in the buffer. We can only save the
-             * write if the buffer is completely zeroed and we're allowed to
-             * keep the target sparse. */
-            if (s->compressed) {
-                if (s->has_zero_init && s->min_sparse &&
-                    buffer_is_zero(buf, n * BDRV_SECTOR_SIZE))
-                {
-                    assert(!s->target_has_backing);
-                    break;
-                }
-
-                iov.iov_base = buf;
-                iov.iov_len = n << BDRV_SECTOR_BITS;
-                qemu_iovec_init_external(&qiov, &iov, 1);
-
-                ret = blk_co_pwritev(s->target, sector_num << BDRV_SECTOR_BITS,
-                                     n << BDRV_SECTOR_BITS, &qiov,
-                                     BDRV_REQ_WRITE_COMPRESSED);
-                if (ret < 0) {
-                    return ret;
-                }
-                break;
-            }
-
-            /* If there is real non-zero data or we're told to keep the target
-             * fully allocated (-S 0), we must write it. Otherwise we can treat
-             * it as zero sectors. */
+            /* If we're told to keep the target fully allocated (-S 0) or there
+             * is real non-zero data, we must write it. Otherwise we can treat
+             * it as zero sectors.
+             * Compressed clusters need to be written as a whole, so in that
+             * case we can only save the write if the buffer is completely
+             * zeroed. */
             if (!s->min_sparse ||
-                is_allocated_sectors_min(buf, n, &n, s->min_sparse))
+                (!s->compressed &&
+                 is_allocated_sectors_min(buf, n, &n, s->min_sparse)) ||
+                (s->compressed &&
+                 !buffer_is_zero(buf, n * BDRV_SECTOR_SIZE)))
             {
                 iov.iov_base = buf;
                 iov.iov_len = n << BDRV_SECTOR_BITS;
                 qemu_iovec_init_external(&qiov, &iov, 1);
 
                 ret = blk_co_pwritev(s->target, sector_num << BDRV_SECTOR_BITS,
-                                     n << BDRV_SECTOR_BITS, &qiov, 0);
+                                     n << BDRV_SECTOR_BITS, &qiov, flags);
                 if (ret < 0) {
                     return ret;
                 }
@@ -1716,6 +1687,7 @@ static int coroutine_fn convert_co_write(ImgConvertState *s, int64_t sector_num,
 
         case BLK_ZERO:
             if (s->has_zero_init) {
+                assert(!s->target_has_backing);
                 break;
             }
             ret = blk_co_pwrite_zeroes(s->target,
@@ -3464,20 +3436,11 @@ static int img_resize(int argc, char **argv)
         goto out;
     }
 
-    ret = blk_truncate(blk, total_size);
-    switch (ret) {
-    case 0:
+    ret = blk_truncate(blk, total_size, &err);
+    if (!ret) {
         qprintf(quiet, "Image resized.\n");
-        break;
-    case -ENOTSUP:
-        error_report("This image does not support resize");
-        break;
-    case -EACCES:
-        error_report("Image is read-only");
-        break;
-    default:
-        error_report("Error resizing image: %s", strerror(-ret));
-        break;
+    } else {
+        error_report_err(err);
     }
 out:
     blk_unref(blk);
diff --git a/qemu-img.texi b/qemu-img.texi
index 8c573ae010..50a2364e80 100644
--- a/qemu-img.texi
+++ b/qemu-img.texi
@@ -84,7 +84,8 @@ with or without a command shows help and lists the supported formats
 @item -p
 display progress bar (compare, convert and rebase commands only).
 If the @var{-p} option is not used for a command that supports it, the
-progress is reported when the process receives a @code{SIGUSR1} signal.
+progress is reported when the process receives a @code{SIGUSR1} or
+@code{SIGINFO} signal.
 @item -q
 Quiet mode - do not print any output (except errors). There's no progress bar
 in case both @var{-q} and @var{-p} options are used.
diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
index 312fc6d157..21af9e65b2 100644
--- a/qemu-io-cmds.c
+++ b/qemu-io-cmds.c
@@ -1567,6 +1567,7 @@ static const cmdinfo_t flush_cmd = {
 
 static int truncate_f(BlockBackend *blk, int argc, char **argv)
 {
+    Error *local_err = NULL;
     int64_t offset;
     int ret;
 
@@ -1576,9 +1577,9 @@ static int truncate_f(BlockBackend *blk, int argc, char **argv)
         return 0;
     }
 
-    ret = blk_truncate(blk, offset);
+    ret = blk_truncate(blk, offset, &local_err);
     if (ret < 0) {
-        printf("truncate: %s\n", strerror(-ret));
+        error_report_err(local_err);
         return 0;
     }
 
diff --git a/tests/qemu-iotests/066 b/tests/qemu-iotests/066
index 364166d3b2..c2116a3088 100755
--- a/tests/qemu-iotests/066
+++ b/tests/qemu-iotests/066
@@ -42,16 +42,18 @@ _supported_fmt qcow2
 _supported_proto generic
 _supported_os Linux
 
+# Intentionally create an unaligned image
 IMGOPTS="compat=1.1"
-IMG_SIZE=64M
+IMG_SIZE=$((64 * 1024 * 1024 + 512))
 
 echo
-echo "=== Testing snapshotting an image with zero clusters ==="
+echo "=== Testing cluster discards ==="
 echo
 _make_test_img $IMG_SIZE
-# Write some normal clusters, zero them (creating preallocated zero clusters)
-# and discard those
-$QEMU_IO -c "write 0 256k" -c "write -z 0 256k" -c "discard 0 256k" "$TEST_IMG" \
+# Write some normal clusters, zero some of them (creating preallocated
+# zero clusters) and discard everything. Everything should now read as 0.
+$QEMU_IO -c "write 0 256k" -c "write -z 0 256k" -c "write 64M 512" \
+	 -c "discard 0 $IMG_SIZE" -c "read -P 0 0 $IMG_SIZE" "$TEST_IMG" \
          | _filter_qemu_io
 # Check the image (there shouldn't be any leaks)
 _check_test_img
diff --git a/tests/qemu-iotests/066.out b/tests/qemu-iotests/066.out
index 7bc9a107d5..7c1f31a1b1 100644
--- a/tests/qemu-iotests/066.out
+++ b/tests/qemu-iotests/066.out
@@ -1,13 +1,17 @@
 QA output created by 066
 
-=== Testing snapshotting an image with zero clusters ===
+=== Testing cluster discards ===
 
-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67109376
 wrote 262144/262144 bytes at offset 0
 256 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 wrote 262144/262144 bytes at offset 0
 256 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
-discard 262144/262144 bytes at offset 0
-256 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 512/512 bytes at offset 67108864
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+discard 67109376/67109376 bytes at offset 0
+64 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+read 67109376/67109376 bytes at offset 0
+64 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 No errors were found on the image.
 *** done
diff --git a/tests/qemu-iotests/common b/tests/qemu-iotests/common
index 9c6f9721e5..f2a7199c4b 100644
--- a/tests/qemu-iotests/common
+++ b/tests/qemu-iotests/common
@@ -86,7 +86,8 @@ s/ .*//p
     elif $xgroup
     then
         # arg after -x
-        [ ! -s $tmp.list ] && ls [0-9][0-9][0-9] [0-9][0-9][0-9][0-9] >$tmp.list 2>/dev/null
+        # Populate $tmp.list with all tests
+        awk '/^[0-9]{3,}/ {print $1}' "${source_iotests}/group" > $tmp.list 2>/dev/null
         group_list=`sed -n <"$source_iotests/group" -e 's/$/ /' -e "/^[0-9][0-9][0-9].* $r /"'{
 s/ .*//p
 }'`
@@ -138,7 +139,7 @@ common options
     -v                  verbose
     -d                  debug
 
-check options
+image format options
     -raw                test raw (default)
     -bochs              test bochs
     -cloop              test cloop
@@ -150,14 +151,18 @@ check options
     -vpc                test vpc
     -vhdx               test vhdx
     -vmdk               test vmdk
+    -luks               test luks
+
+image protocol options
     -file               test file (default)
     -rbd                test rbd
     -sheepdog           test sheepdog
     -nbd                test nbd
     -ssh                test ssh
     -nfs                test nfs
-    -luks               test luks
     -vxhs               test vxhs
+
+other options
     -xdiff              graphical mode diff
     -nocache            use O_DIRECT on backing file
     -misalign           misalign memory allocations
diff --git a/util/qemu-progress.c b/util/qemu-progress.c
index f745233763..3c2223c1a2 100644
--- a/util/qemu-progress.c
+++ b/util/qemu-progress.c
@@ -88,6 +88,9 @@ static void progress_dummy_init(void)
     action.sa_handler = sigusr_print;
     action.sa_flags = 0;
     sigaction(SIGUSR1, &action, NULL);
+#ifdef SIGINFO
+    sigaction(SIGINFO, &action, NULL);
+#endif
 
     /*
      * SIGUSR1 is SIG_IPI and gets blocked in qemu_init_main_loop(). In the