Merge remote-tracking branch 'remotes/maxreitz/tags/pull-block-2020-02-20' into staging

Block patches:
- qemu-img convert: New --target-is-zero parameter
- qcow2: Specify non-default compression type flag
- optionally flat output for query-named-block-nodes
- some fixes
- pseudo-creation of images on block devices is now done by a generic
  block layer function

# gpg: Signature made Thu 20 Feb 2020 16:05:34 GMT
# gpg:                using RSA key 91BEB60A30DB3E8857D11829F407DB0061D5CF40
# gpg:                issuer "mreitz@redhat.com"
# gpg: Good signature from "Max Reitz <mreitz@redhat.com>" [full]
# Primary key fingerprint: 91BE B60A 30DB 3E88 57D1  1829 F407 DB00 61D5 CF40

* remotes/maxreitz/tags/pull-block-2020-02-20:
  iotests: Test snapshot -l field separation
  block: Fix VM size field width in snapshot dump
  iotests: Test convert -n -B to backing-less target
  qemu-img: Fix convert -n -B for backing-less targets
  iotests: Add test for image creation fallback
  iscsi: Drop iscsi_co_create_opts()
  file-posix: Drop hdev_co_create_opts()
  block: Generic file creation fallback
  block/nbd: Fix hang in .bdrv_close()
  iotests/279: Fix for non-qcow2 formats
  block/backup-top: fix flags handling
  block: always fill entire LUKS header space with zeros
  qemu-img: Add --target-is-zero to convert
  qapi: Allow getting flat output from 'query-named-block-nodes'
  iotests/147: Fix drive parameters
  iotests: Remove the superfluous 2nd check for the availability of quorum
  docs: qcow2: introduce compression type feature
  docs: improve qcow2 spec about extending image header
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

block.c

@@ -532,20 +532,139 @@ out:
     return ret;
 }
 
-int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
+/**
+ * Helper function for bdrv_create_file_fallback(): Resize @blk to at
+ * least the given @minimum_size.
+ *
+ * On success, return @blk's actual length.
+ * Otherwise, return -errno.
+ */
+static int64_t create_file_fallback_truncate(BlockBackend *blk,
+                                             int64_t minimum_size, Error **errp)
 {
-    BlockDriver *drv;
+    Error *local_err = NULL;
+    int64_t size;
+    int ret;
+
+    ret = blk_truncate(blk, minimum_size, false, PREALLOC_MODE_OFF, &local_err);
+    if (ret < 0 && ret != -ENOTSUP) {
+        error_propagate(errp, local_err);
+        return ret;
+    }
+
+    size = blk_getlength(blk);
+    if (size < 0) {
+        error_free(local_err);
+        error_setg_errno(errp, -size,
+                         "Failed to inquire the new image file's length");
+        return size;
+    }
+
+    if (size < minimum_size) {
+        /* Need to grow the image, but we failed to do that */
+        error_propagate(errp, local_err);
+        return -ENOTSUP;
+    }
+
+    error_free(local_err);
+    local_err = NULL;
+
+    return size;
+}
+
+/**
+ * Helper function for bdrv_create_file_fallback(): Zero the first
+ * sector to remove any potentially pre-existing image header.
+ */
+static int create_file_fallback_zero_first_sector(BlockBackend *blk,
+                                                  int64_t current_size,
+                                                  Error **errp)
+{
+    int64_t bytes_to_clear;
+    int ret;
+
+    bytes_to_clear = MIN(current_size, BDRV_SECTOR_SIZE);
+    if (bytes_to_clear) {
+        ret = blk_pwrite_zeroes(blk, 0, bytes_to_clear, BDRV_REQ_MAY_UNMAP);
+        if (ret < 0) {
+            error_setg_errno(errp, -ret,
+                             "Failed to clear the new image's first sector");
+            return ret;
+        }
+    }
+
+    return 0;
+}
+
+static int bdrv_create_file_fallback(const char *filename, BlockDriver *drv,
+                                     QemuOpts *opts, Error **errp)
+{
+    BlockBackend *blk;
+    QDict *options = qdict_new();
+    int64_t size = 0;
+    char *buf = NULL;
+    PreallocMode prealloc;
     Error *local_err = NULL;
     int ret;
 
+    size = qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0);
+    buf = qemu_opt_get_del(opts, BLOCK_OPT_PREALLOC);
+    prealloc = qapi_enum_parse(&PreallocMode_lookup, buf,
+                               PREALLOC_MODE_OFF, &local_err);
+    g_free(buf);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return -EINVAL;
+    }
+
+    if (prealloc != PREALLOC_MODE_OFF) {
+        error_setg(errp, "Unsupported preallocation mode '%s'",
+                   PreallocMode_str(prealloc));
+        return -ENOTSUP;
+    }
+
+    qdict_put_str(options, "driver", drv->format_name);
+
+    blk = blk_new_open(filename, NULL, options,
+                       BDRV_O_RDWR | BDRV_O_RESIZE, errp);
+    if (!blk) {
+        error_prepend(errp, "Protocol driver '%s' does not support image "
+                      "creation, and opening the image failed: ",
+                      drv->format_name);
+        return -EINVAL;
+    }
+
+    size = create_file_fallback_truncate(blk, size, errp);
+    if (size < 0) {
+        ret = size;
+        goto out;
+    }
+
+    ret = create_file_fallback_zero_first_sector(blk, size, errp);
+    if (ret < 0) {
+        goto out;
+    }
+
+    ret = 0;
+out:
+    blk_unref(blk);
+    return ret;
+}
+
+int bdrv_create_file(const char *filename, QemuOpts *opts, Error **errp)
+{
+    BlockDriver *drv;
+
     drv = bdrv_find_protocol(filename, true, errp);
     if (drv == NULL) {
         return -ENOENT;
     }
 
-    ret = bdrv_create(drv, filename, opts, &local_err);
-    error_propagate(errp, local_err);
-    return ret;
+    if (drv->bdrv_co_create_opts) {
+        return bdrv_create(drv, filename, opts, errp);
+    } else {
+        return bdrv_create_file_fallback(filename, drv, opts, errp);
+    }
 }
 
 /**
@@ -1444,6 +1563,24 @@ QemuOptsList bdrv_runtime_opts = {
     },
 };
 
+static QemuOptsList fallback_create_opts = {
+    .name = "fallback-create-opts",
+    .head = QTAILQ_HEAD_INITIALIZER(fallback_create_opts.head),
+    .desc = {
+        {
+            .name = BLOCK_OPT_SIZE,
+            .type = QEMU_OPT_SIZE,
+            .help = "Virtual disk size"
+        },
+        {
+            .name = BLOCK_OPT_PREALLOC,
+            .type = QEMU_OPT_STRING,
+            .help = "Preallocation mode (allowed values: off)"
+        },
+        { /* end of list */ }
+    }
+};
+
 /*
  * Common part for opening disk images and files
  *
@@ -4807,14 +4944,15 @@ BlockDriverState *bdrv_find_node(const char *node_name)
 }
 
 /* Put this QMP function here so it can access the static graph_bdrv_states. */
-BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp)
+BlockDeviceInfoList *bdrv_named_nodes_list(bool flat,
+                                           Error **errp)
 {
     BlockDeviceInfoList *list, *entry;
     BlockDriverState *bs;
 
     list = NULL;
     QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
-        BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, errp);
+        BlockDeviceInfo *info = bdrv_block_device_info(NULL, bs, flat, errp);
         if (!info) {
             qapi_free_BlockDeviceInfoList(list);
             return NULL;
@@ -5771,15 +5909,13 @@ void bdrv_img_create(const char *filename, const char *fmt,
         return;
     }
 
-    if (!proto_drv->create_opts) {
-        error_setg(errp, "Protocol driver '%s' does not support image creation",
-                   proto_drv->format_name);
-        return;
-    }
-
     /* Create parameter list */
     create_opts = qemu_opts_append(create_opts, drv->create_opts);
-    create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
+    if (proto_drv->create_opts) {
+        create_opts = qemu_opts_append(create_opts, proto_drv->create_opts);
+    } else {
+        create_opts = qemu_opts_append(create_opts, &fallback_create_opts);
+    }
 
     opts = qemu_opts_create(create_opts, NULL, 0, &error_abort);
 

block/backup-top.c

@@ -48,11 +48,17 @@ static coroutine_fn int backup_top_co_preadv(
 }
 
 static coroutine_fn int backup_top_cbw(BlockDriverState *bs, uint64_t offset,
-                                       uint64_t bytes)
+                                       uint64_t bytes, BdrvRequestFlags flags)
 {
     BDRVBackupTopState *s = bs->opaque;
-    uint64_t end = QEMU_ALIGN_UP(offset + bytes, s->bcs->cluster_size);
-    uint64_t off = QEMU_ALIGN_DOWN(offset, s->bcs->cluster_size);
+    uint64_t off, end;
+
+    if (flags & BDRV_REQ_WRITE_UNCHANGED) {
+        return 0;
+    }
+
+    off = QEMU_ALIGN_DOWN(offset, s->bcs->cluster_size);
+    end = QEMU_ALIGN_UP(offset + bytes, s->bcs->cluster_size);
 
     return block_copy(s->bcs, off, end - off, NULL);
 }
@@ -60,7 +66,7 @@ static coroutine_fn int backup_top_cbw(BlockDriverState *bs, uint64_t offset,
 static int coroutine_fn backup_top_co_pdiscard(BlockDriverState *bs,
                                                int64_t offset, int bytes)
 {
-    int ret = backup_top_cbw(bs, offset, bytes);
+    int ret = backup_top_cbw(bs, offset, bytes, 0);
     if (ret < 0) {
         return ret;
     }
@@ -71,7 +77,7 @@ static int coroutine_fn backup_top_co_pdiscard(BlockDriverState *bs,
 static int coroutine_fn backup_top_co_pwrite_zeroes(BlockDriverState *bs,
         int64_t offset, int bytes, BdrvRequestFlags flags)
 {
-    int ret = backup_top_cbw(bs, offset, bytes);
+    int ret = backup_top_cbw(bs, offset, bytes, flags);
     if (ret < 0) {
         return ret;
     }
@@ -84,11 +90,9 @@ static coroutine_fn int backup_top_co_pwritev(BlockDriverState *bs,
                                               uint64_t bytes,
                                               QEMUIOVector *qiov, int flags)
 {
-    if (!(flags & BDRV_REQ_WRITE_UNCHANGED)) {
-        int ret = backup_top_cbw(bs, offset, bytes);
-        if (ret < 0) {
-            return ret;
-        }
+    int ret = backup_top_cbw(bs, offset, bytes, flags);
+    if (ret < 0) {
+        return ret;
     }
 
     return bdrv_co_pwritev(bs->backing, offset, bytes, qiov, flags);
@@ -196,8 +200,13 @@ BlockDriverState *bdrv_backup_top_append(BlockDriverState *source,
         return NULL;
     }
 
-    top->total_sectors = source->total_sectors;
     state = top->opaque;
+    top->total_sectors = source->total_sectors;
+    top->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED |
+            (BDRV_REQ_FUA & source->supported_write_flags);
+    top->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED |
+            ((BDRV_REQ_FUA | BDRV_REQ_MAY_UNMAP | BDRV_REQ_NO_FALLBACK) &
+             source->supported_zero_flags);
 
     bdrv_ref(target);
     state->target = bdrv_attach_child(top, target, "target", &child_file, errp);

block/file-posix.c

@@ -3477,67 +3477,6 @@ static coroutine_fn int hdev_co_pwrite_zeroes(BlockDriverState *bs,
     return raw_do_pwrite_zeroes(bs, offset, bytes, flags, true);
 }
 
-static int coroutine_fn hdev_co_create_opts(const char *filename, QemuOpts *opts,
-                                            Error **errp)
-{
-    int fd;
-    int ret = 0;
-    struct stat stat_buf;
-    int64_t total_size = 0;
-    bool has_prefix;
-
-    /* This function is used by both protocol block drivers and therefore either
-     * of these prefixes may be given.
-     * The return value has to be stored somewhere, otherwise this is an error
-     * due to -Werror=unused-value. */
-    has_prefix =
-        strstart(filename, "host_device:", &filename) ||
-        strstart(filename, "host_cdrom:" , &filename);
-
-    (void)has_prefix;
-
-    ret = raw_normalize_devicepath(&filename, errp);
-    if (ret < 0) {
-        return ret;
-    }
-
-    /* Read out options */
-    total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
-                          BDRV_SECTOR_SIZE);
-
-    fd = qemu_open(filename, O_WRONLY | O_BINARY);
-    if (fd < 0) {
-        ret = -errno;
-        error_setg_errno(errp, -ret, "Could not open device");
-        return ret;
-    }
-
-    if (fstat(fd, &stat_buf) < 0) {
-        ret = -errno;
-        error_setg_errno(errp, -ret, "Could not stat device");
-    } else if (!S_ISBLK(stat_buf.st_mode) && !S_ISCHR(stat_buf.st_mode)) {
-        error_setg(errp,
-                   "The given file is neither a block nor a character device");
-        ret = -ENODEV;
-    } else if (lseek(fd, 0, SEEK_END) < total_size) {
-        error_setg(errp, "Device is too small");
-        ret = -ENOSPC;
-    }
-
-    if (!ret && total_size) {
-        uint8_t buf[BDRV_SECTOR_SIZE] = { 0 };
-        int64_t zero_size = MIN(BDRV_SECTOR_SIZE, total_size);
-        if (lseek(fd, 0, SEEK_SET) == -1) {
-            ret = -errno;
-        } else {
-            ret = qemu_write_full(fd, buf, zero_size);
-            ret = ret == zero_size ? 0 : -errno;
-        }
-    }
-    qemu_close(fd);
-    return ret;
-}
-
 static BlockDriver bdrv_host_device = {
     .format_name        = "host_device",
     .protocol_name        = "host_device",
@@ -3550,8 +3489,6 @@ static BlockDriver bdrv_host_device = {
     .bdrv_reopen_prepare = raw_reopen_prepare,
     .bdrv_reopen_commit  = raw_reopen_commit,
     .bdrv_reopen_abort   = raw_reopen_abort,
-    .bdrv_co_create_opts = hdev_co_create_opts,
-    .create_opts         = &raw_create_opts,
     .mutable_opts        = mutable_opts,
     .bdrv_co_invalidate_cache = raw_co_invalidate_cache,
     .bdrv_co_pwrite_zeroes = hdev_co_pwrite_zeroes,
@@ -3678,8 +3615,6 @@ static BlockDriver bdrv_host_cdrom = {
     .bdrv_reopen_prepare = raw_reopen_prepare,
     .bdrv_reopen_commit  = raw_reopen_commit,
     .bdrv_reopen_abort   = raw_reopen_abort,
-    .bdrv_co_create_opts = hdev_co_create_opts,
-    .create_opts         = &raw_create_opts,
     .mutable_opts        = mutable_opts,
     .bdrv_co_invalidate_cache = raw_co_invalidate_cache,
 
@@ -3812,8 +3747,6 @@ static BlockDriver bdrv_host_cdrom = {
     .bdrv_reopen_prepare = raw_reopen_prepare,
     .bdrv_reopen_commit  = raw_reopen_commit,
     .bdrv_reopen_abort   = raw_reopen_abort,
-    .bdrv_co_create_opts = hdev_co_create_opts,
-    .create_opts        = &raw_create_opts,
     .mutable_opts       = mutable_opts,
 
     .bdrv_co_preadv         = raw_co_preadv,

block/iscsi.c

@@ -2164,58 +2164,6 @@ static int coroutine_fn iscsi_co_truncate(BlockDriverState *bs, int64_t offset,
     return 0;
 }
 
-static int coroutine_fn iscsi_co_create_opts(const char *filename, QemuOpts *opts,
-                                             Error **errp)
-{
-    int ret = 0;
-    int64_t total_size = 0;
-    BlockDriverState *bs;
-    IscsiLun *iscsilun = NULL;
-    QDict *bs_options;
-    Error *local_err = NULL;
-
-    bs = bdrv_new();
-
-    /* Read out options */
-    total_size = DIV_ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
-                              BDRV_SECTOR_SIZE);
-    bs->opaque = g_new0(struct IscsiLun, 1);
-    iscsilun = bs->opaque;
-
-    bs_options = qdict_new();
-    iscsi_parse_filename(filename, bs_options, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
-        ret = -EINVAL;
-    } else {
-        ret = iscsi_open(bs, bs_options, 0, NULL);
-    }
-    qobject_unref(bs_options);
-
-    if (ret != 0) {
-        goto out;
-    }
-    iscsi_detach_aio_context(bs);
-    if (iscsilun->type != TYPE_DISK) {
-        ret = -ENODEV;
-        goto out;
-    }
-    if (bs->total_sectors < total_size) {
-        ret = -ENOSPC;
-        goto out;
-    }
-
-    ret = 0;
-out:
-    if (iscsilun->iscsi != NULL) {
-        iscsi_destroy_context(iscsilun->iscsi);
-    }
-    g_free(bs->opaque);
-    bs->opaque = NULL;
-    bdrv_unref(bs);
-    return ret;
-}
-
 static int iscsi_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 {
     IscsiLun *iscsilun = bs->opaque;
@@ -2486,8 +2434,6 @@ static BlockDriver bdrv_iscsi = {
     .bdrv_parse_filename    = iscsi_parse_filename,
     .bdrv_file_open         = iscsi_open,
     .bdrv_close             = iscsi_close,
-    .bdrv_co_create_opts    = iscsi_co_create_opts,
-    .create_opts            = &iscsi_create_opts,
     .bdrv_reopen_prepare    = iscsi_reopen_prepare,
     .bdrv_reopen_commit     = iscsi_reopen_commit,
     .bdrv_co_invalidate_cache = iscsi_co_invalidate_cache,
@@ -2525,8 +2471,6 @@ static BlockDriver bdrv_iser = {
     .bdrv_parse_filename    = iscsi_parse_filename,
     .bdrv_file_open         = iscsi_open,
     .bdrv_close             = iscsi_close,
-    .bdrv_co_create_opts    = iscsi_co_create_opts,
-    .create_opts            = &iscsi_create_opts,
     .bdrv_reopen_prepare    = iscsi_reopen_prepare,
     .bdrv_reopen_commit     = iscsi_reopen_commit,
     .bdrv_co_invalidate_cache  = iscsi_co_invalidate_cache,

block/nbd.c

@@ -70,6 +70,7 @@ typedef struct BDRVNBDState {
     CoMutex send_mutex;
     CoQueue free_sema;
     Coroutine *connection_co;
+    Coroutine *teardown_co;
     QemuCoSleepState *connection_co_sleep_ns_state;
     bool drained;
     bool wait_drained_end;
@@ -203,7 +204,15 @@ static void nbd_teardown_connection(BlockDriverState *bs)
             qemu_co_sleep_wake(s->connection_co_sleep_ns_state);
         }
     }
-    BDRV_POLL_WHILE(bs, s->connection_co);
+    if (qemu_in_coroutine()) {
+        s->teardown_co = qemu_coroutine_self();
+        /* connection_co resumes us when it terminates */
+        qemu_coroutine_yield();
+        s->teardown_co = NULL;
+    } else {
+        BDRV_POLL_WHILE(bs, s->connection_co);
+    }
+    assert(!s->connection_co);
 }
 
 static bool nbd_client_connecting(BDRVNBDState *s)
@@ -395,6 +404,9 @@ static coroutine_fn void nbd_connection_entry(void *opaque)
         s->ioc = NULL;
     }
 
+    if (s->teardown_co) {
+        aio_co_wake(s->teardown_co);
+    }
     aio_wait_kick();
 }
 

block/qapi.c

@@ -42,7 +42,9 @@
 #include "qemu/cutils.h"
 
 BlockDeviceInfo *bdrv_block_device_info(BlockBackend *blk,
-                                        BlockDriverState *bs, Error **errp)
+                                        BlockDriverState *bs,
+                                        bool flat,
+                                        Error **errp)
 {
     ImageInfo **p_image_info;
     BlockDriverState *bs0;
@@ -156,6 +158,11 @@ BlockDeviceInfo *bdrv_block_device_info(BlockBackend *blk,
             return NULL;
         }
 
+        /* stop gathering data for flat output */
+        if (flat) {
+            break;
+        }
+
         if (bs0->drv && bs0->backing) {
             info->backing_file_depth++;
             bs0 = bs0->backing->bs;
@@ -389,7 +396,7 @@ static void bdrv_query_info(BlockBackend *blk, BlockInfo **p_info,
 
     if (bs && bs->drv) {
         info->has_inserted = true;
-        info->inserted = bdrv_block_device_info(blk, bs, errp);
+        info->inserted = bdrv_block_device_info(blk, bs, false, errp);
         if (info->inserted == NULL) {
             goto err;
         }
@@ -657,7 +664,7 @@ void bdrv_snapshot_dump(QEMUSnapshotInfo *sn)
     char *sizing = NULL;
 
     if (!sn) {
-        qemu_printf("%-10s%-20s%7s%20s%15s",
+        qemu_printf("%-10s%-20s%11s%20s%15s",
                     "ID", "TAG", "VM SIZE", "DATE", "VM CLOCK");
     } else {
         ti = sn->date_sec;
@@ -672,7 +679,7 @@ void bdrv_snapshot_dump(QEMUSnapshotInfo *sn)
                  (int)(secs % 60),
                  (int)((sn->vm_clock_nsec / 1000000) % 1000));
         sizing = size_to_str(sn->vm_state_size);
-        qemu_printf("%-10s%-20s%7s%20s%15s",
+        qemu_printf("%-10s%-20s%11s%20s%15s",
                     sn->id_str, sn->name,
                     sizing,
                     date_buf,

block/qcow2.c

@@ -135,13 +135,16 @@ static ssize_t qcow2_crypto_hdr_init_func(QCryptoBlock *block, size_t headerlen,
     s->crypto_header.length = headerlen;
     s->crypto_header.offset = ret;
 
-    /* Zero fill remaining space in cluster so it has predictable
-     * content in case of future spec changes */
+    /*
+     * Zero fill all space in cluster so it has predictable
+     * content, as we may not initialize some regions of the
+     * header (eg only 1 out of 8 key slots will be initialized)
+     */
     clusterlen = size_to_clusters(s, headerlen) * s->cluster_size;
     assert(qcow2_pre_write_overlap_check(bs, 0, ret, clusterlen, false) == 0);
     ret = bdrv_pwrite_zeroes(bs->file,
-                             ret + headerlen,
-                             clusterlen - headerlen, 0);
+                             ret,
+                             clusterlen, 0);
     if (ret < 0) {
         error_setg_errno(errp, -ret, "Could not zero fill encryption header");
         return -1;

blockdev.c

@@ -3734,9 +3734,13 @@ void qmp_drive_backup(DriveBackup *backup, Error **errp)
     blockdev_do_action(&action, errp);
 }
 
-BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp)
+BlockDeviceInfoList *qmp_query_named_block_nodes(bool has_flat,
+                                                 bool flat,
+                                                 Error **errp)
 {
-    return bdrv_named_nodes_list(errp);
+    bool return_flat = has_flat && flat;
+
+    return bdrv_named_nodes_list(return_flat, errp);
 }
 
 XDbgBlockGraph *qmp_x_debug_query_block_graph(Error **errp)

docs/interop/qcow2.txt

@@ -79,9 +79,9 @@ The first cluster of a qcow2 image contains the file header:
                     Offset into the image file at which the snapshot table
                     starts. Must be aligned to a cluster boundary.
 
-If the version is 3 or higher, the header has the following additional fields.
-For version 2, the values are assumed to be zero, unless specified otherwise
-in the description of a field.
+For version 2, the header is exactly 72 bytes in length, and finishes here.
+For version 3 or higher, the header length is at least 104 bytes, including
+the next fields through header_length.
 
          72 -  79:  incompatible_features
                     Bitmask of incompatible features. An implementation must
@@ -109,7 +109,12 @@ in the description of a field.
                                 An External Data File Name header extension may
                                 be present if this bit is set.
 
-                    Bits 3-63:  Reserved (set to 0)
+                    Bit 3:      Compression type bit.  If this bit is set,
+                                a non-default compression is used for compressed
+                                clusters. The compression_type field must be
+                                present and not zero.
+
+                    Bits 4-63:  Reserved (set to 0)
 
          80 -  87:  compatible_features
                     Bitmask of compatible features. An implementation can
@@ -164,6 +169,57 @@ in the description of a field.
         100 - 103:  header_length
                     Length of the header structure in bytes. For version 2
                     images, the length is always assumed to be 72 bytes.
+                    For version 3 it's at least 104 bytes and must be a multiple
+                    of 8.
+
+
+=== Additional fields (version 3 and higher) ===
+
+In general, these fields are optional and may be safely ignored by the software,
+as well as filled by zeros (which is equal to field absence), if software needs
+to set field B, but does not care about field A which precedes B. More
+formally, additional fields have the following compatibility rules:
+
+1. If the value of the additional field must not be ignored for correct
+handling of the file, it will be accompanied by a corresponding incompatible
+feature bit.
+
+2. If there are no unrecognized incompatible feature bits set, an unknown
+additional field may be safely ignored other than preserving its value when
+rewriting the image header.
+
+3. An explicit value of 0 will have the same behavior as when the field is not
+present*, if not altered by a specific incompatible bit.
+
+*. A field is considered not present when header_length is less than or equal
+to the field's offset. Also, all additional fields are not present for
+version 2.
+
+              104:  compression_type
+
+                    Defines the compression method used for compressed clusters.
+                    All compressed clusters in an image use the same compression
+                    type.
+
+                    If the incompatible bit "Compression type" is set: the field
+                    must be present and non-zero (which means non-zlib
+                    compression type). Otherwise, this field must not be present
+                    or must be zero (which means zlib).
+
+                    Available compression type values:
+                        0: zlib <https://www.zlib.net/>
+
+
+=== Header padding ===
+
+@header_length must be a multiple of 8, which means that if the end of the last
+additional field is not aligned, some padding is needed. This padding must be
+zeroed, so that if some existing (or future) additional field will fall into
+the padding, it will be interpreted accordingly to point [3.] of the previous
+paragraph, i.e.  in the same manner as when this field is not present.
+
+
+=== Header extensions ===
 
 Directly after the image header, optional sections called header extensions can
 be stored. Each extension has a structure like the following:

docs/interop/qemu-img.rst

@@ -214,6 +214,13 @@ Parameters to convert subcommand:
   will still be printed.  Areas that cannot be read from the source will be
   treated as containing only zeroes.
 
+.. option:: --target-is-zero
+
+  Assume that reading the destination image will always return
+  zeros. This parameter is mutually exclusive with a destination image
+  that has a backing file. It is required to also use the ``-n``
+  parameter to skip image creation.
+
 Parameters to dd subcommand:
 
 .. program:: qemu-img-dd
@@ -366,7 +373,7 @@ Command description:
   4
     Error on reading data
 
-.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-m NUM_COROUTINES] [-W] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
+.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-m NUM_COROUTINES] [-W] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
 
   Convert the disk image *FILENAME* or a snapshot *SNAPSHOT_PARAM*
   to disk image *OUTPUT_FILENAME* using format *OUTPUT_FMT*. It can

include/block/block.h

@@ -454,7 +454,7 @@ void bdrv_lock_medium(BlockDriverState *bs, bool locked);
 void bdrv_eject(BlockDriverState *bs, bool eject_flag);
 const char *bdrv_get_format_name(BlockDriverState *bs);
 BlockDriverState *bdrv_find_node(const char *node_name);
-BlockDeviceInfoList *bdrv_named_nodes_list(Error **errp);
+BlockDeviceInfoList *bdrv_named_nodes_list(bool flat, Error **errp);
 XDbgBlockGraph *bdrv_get_xdbg_block_graph(Error **errp);
 BlockDriverState *bdrv_lookup_bs(const char *device,
                                  const char *node_name,

include/block/qapi.h

@@ -29,7 +29,9 @@
 #include "block/snapshot.h"
 
 BlockDeviceInfo *bdrv_block_device_info(BlockBackend *blk,
-                                        BlockDriverState *bs, Error **errp);
+                                        BlockDriverState *bs,
+                                        bool flat,
+                                        Error **errp);
 int bdrv_query_snapshot_info_list(BlockDriverState *bs,
                                   SnapshotInfoList **p_list,
                                   Error **errp);

monitor/hmp-cmds.c

@@ -620,7 +620,7 @@ void hmp_info_block(Monitor *mon, const QDict *qdict)
     }
 
     /* Print node information */
-    blockdev_list = qmp_query_named_block_nodes(NULL);
+    blockdev_list = qmp_query_named_block_nodes(false, false, NULL);
     for (blockdev = blockdev_list; blockdev; blockdev = blockdev->next) {
         assert(blockdev->value->has_node_name);
         if (device && strcmp(device, blockdev->value->node_name)) {

qapi/block-core.json

@@ -1758,6 +1758,9 @@
 #
 # Get the named block driver list
 #
+# @flat: Omit the nested data about backing image ("backing-image" key) if true.
+#        Default is false (Since 5.0)
+#
 # Returns: the list of BlockDeviceInfo
 #
 # Since: 2.0
@@ -1811,7 +1814,9 @@
 #                    } } ] }
 #
 ##
-{ 'command': 'query-named-block-nodes', 'returns': [ 'BlockDeviceInfo' ] }
+{ 'command': 'query-named-block-nodes',
+  'returns': [ 'BlockDeviceInfo' ],
+  'data': { '*flat': 'bool' } }
 
 ##
 # @XDbgBlockGraphNodeType:

qemu-img-cmds.hx

@@ -39,9 +39,9 @@ SRST
 ERST
 
 DEF("convert", img_convert,
-    "convert [--object objectdef] [--image-opts] [--target-image-opts] [-U] [-C] [-c] [-p] [-q] [-n] [-f fmt] [-t cache] [-T src_cache] [-O output_fmt] [-B backing_file] [-o options] [-l snapshot_param] [-S sparse_size] [-m num_coroutines] [-W] [--salvage] filename [filename2 [...]] output_filename")
+    "convert [--object objectdef] [--image-opts] [--target-image-opts] [--target-is-zero] [-U] [-C] [-c] [-p] [-q] [-n] [-f fmt] [-t cache] [-T src_cache] [-O output_fmt] [-B backing_file] [-o options] [-l snapshot_param] [-S sparse_size] [-m num_coroutines] [-W] [--salvage] filename [filename2 [...]] output_filename")
 SRST
-.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-m NUM_COROUTINES] [-W] [--salvage] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
+.. option:: convert [--object OBJECTDEF] [--image-opts] [--target-image-opts] [--target-is-zero] [-U] [-C] [-c] [-p] [-q] [-n] [-f FMT] [-t CACHE] [-T SRC_CACHE] [-O OUTPUT_FMT] [-B BACKING_FILE] [-o OPTIONS] [-l SNAPSHOT_PARAM] [-S SPARSE_SIZE] [-m NUM_COROUTINES] [-W] [--salvage] FILENAME [FILENAME2 [...]] OUTPUT_FILENAME
 ERST
 
 DEF("create", img_create,

qemu-img.c

@@ -70,6 +70,7 @@ enum {
     OPTION_PREALLOCATION = 265,
     OPTION_SHRINK = 266,
     OPTION_SALVAGE = 267,
+    OPTION_TARGET_IS_ZERO = 268,
 };
 
 typedef enum OutputFormat {
@@ -1984,10 +1985,9 @@ static int convert_do_copy(ImgConvertState *s)
     int64_t sector_num = 0;
 
     /* Check whether we have zero initialisation or can get it efficiently */
-    if (s->target_is_new && s->min_sparse && !s->target_has_backing) {
+    if (!s->has_zero_init && s->target_is_new && s->min_sparse &&
+        !s->target_has_backing) {
         s->has_zero_init = bdrv_has_zero_init(blk_bs(s->target));
-    } else {
-        s->has_zero_init = false;
     }
 
     if (!s->has_zero_init && !s->target_has_backing &&
@@ -2086,6 +2086,7 @@ static int img_convert(int argc, char **argv)
             {"force-share", no_argument, 0, 'U'},
             {"target-image-opts", no_argument, 0, OPTION_TARGET_IMAGE_OPTS},
             {"salvage", no_argument, 0, OPTION_SALVAGE},
+            {"target-is-zero", no_argument, 0, OPTION_TARGET_IS_ZERO},
             {0, 0, 0, 0}
         };
         c = getopt_long(argc, argv, ":hf:O:B:Cco:l:S:pt:T:qnm:WU",
@@ -2209,6 +2210,14 @@ static int img_convert(int argc, char **argv)
         case OPTION_TARGET_IMAGE_OPTS:
             tgt_image_opts = true;
             break;
+        case OPTION_TARGET_IS_ZERO:
+            /*
+             * The user asserting that the target is blank has the
+             * same effect as the target driver supporting zero
+             * initialisation.
+             */
+            s.has_zero_init = true;
+            break;
         }
     }
 
@@ -2247,6 +2256,11 @@ static int img_convert(int argc, char **argv)
         warn_report("This will become an error in future QEMU versions.");
     }
 
+    if (s.has_zero_init && !skip_create) {
+        error_report("--target-is-zero requires use of -n flag");
+        goto fail_getopt;
+    }
+
     s.src_num = argc - optind - 1;
     out_filename = s.src_num >= 1 ? argv[argc - 1] : NULL;
 
@@ -2380,6 +2394,12 @@ static int img_convert(int argc, char **argv)
     }
     s.target_has_backing = (bool) out_baseimg;
 
+    if (s.has_zero_init && s.target_has_backing) {
+        error_report("Cannot use --target-is-zero when the destination "
+                     "image has a backing file");
+        goto out;
+    }
+
     if (s.src_num > 1 && out_baseimg) {
         error_report("Having a backing file for the target makes no sense when "
                      "concatenating multiple input images");
@@ -2503,7 +2523,7 @@ static int img_convert(int argc, char **argv)
         }
     }
 
-    if (s.target_has_backing) {
+    if (s.target_has_backing && s.target_is_new) {
         /* Errors are treated as "backing length unknown" (which means
          * s.target_backing_sectors has to be negative, which it will
          * be automatically).  The backing file length is used only

tests/qemu-iotests/122

@@ -276,6 +276,20 @@ $QEMU_IMG convert -O $IMGFMT -n "$TEST_IMG" "$TEST_IMG".orig
 
 $QEMU_IMG compare "$TEST_IMG" "$TEST_IMG".orig
 
+echo
+echo '=== -n -B to an image without a backing file ==='
+echo
+
+# Base for the output
+TEST_IMG="$TEST_IMG".base _make_test_img 64M
+
+# Output that does have $TEST_IMG.base set as its (implicit) backing file
+TEST_IMG="$TEST_IMG".orig _make_test_img 64M
+
+# Convert with -n, which should not confuse -B with "target BDS has a
+# backing file"
+$QEMU_IMG convert -O $IMGFMT -B "$TEST_IMG".base -n "$TEST_IMG" "$TEST_IMG".orig
+
 # success, all done
 echo '*** done'
 rm -f $seq.full

tests/qemu-iotests/122.out

@@ -228,4 +228,9 @@ Formatting 'TEST_DIR/t.IMGFMT.orig', 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)
 Images are identical.
+
+=== -n -B to an image without a backing file ===
+
+Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=67108864
+Formatting 'TEST_DIR/t.IMGFMT.orig', fmt=IMGFMT size=67108864
 *** done

tests/qemu-iotests/139

@@ -344,9 +344,6 @@ class TestBlockdevDel(iotests.QMPTestCase):
 
     @iotests.skip_if_unsupported(['quorum'])
     def testQuorum(self):
-        if not iotests.supports_quorum():
-            return
-
         self.addQuorum('quorum0', 'node0', 'node1')
         # We cannot remove the children of a Quorum device
         self.delBlockDriverState('node0', expect_error = True)

tests/qemu-iotests/147

@@ -134,7 +134,7 @@ class BuiltinNBD(NBDBlockdevAddBase):
         self.server.add_drive_raw('if=none,id=nbd-export,' +
                                   'file=%s,' % test_img +
                                   'format=%s,' % imgfmt +
-                                  'cache=%s' % cachemode +
+                                  'cache=%s,' % cachemode +
                                   'aio=%s' % aiomode)
         self.server.launch()
 

tests/qemu-iotests/259

+#!/usr/bin/env bash
+#
+# Test generic image creation fallback (by using NBD)
+#
+# Copyright (C) 2019 Red Hat, Inc.
+#
+# 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=mreitz@redhat.com
+
+seq=$(basename $0)
+echo "QA output created by $seq"
+
+status=1	# failure is the default!
+
+_cleanup()
+{
+    _cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt raw
+_supported_proto nbd
+_supported_os Linux
+
+
+_make_test_img 64M
+
+echo
+echo '--- Testing creation ---'
+
+$QEMU_IMG create -f qcow2 "$TEST_IMG" 64M | _filter_img_create
+$QEMU_IMG info "$TEST_IMG" | _filter_img_info
+
+echo
+echo '--- Testing creation for which the node would need to grow ---'
+
+# NBD does not support resizing, so this will fail
+$QEMU_IMG create -f qcow2 -o preallocation=metadata "$TEST_IMG" 64M 2>&1 \
+    | _filter_img_create
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0

tests/qemu-iotests/259.out

+QA output created by 259
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
+
+--- Testing creation ---
+Formatting 'TEST_DIR/t.IMGFMT', fmt=qcow2 size=67108864
+image: TEST_DIR/t.IMGFMT
+file format: qcow2
+virtual size: 64 MiB (67108864 bytes)
+disk size: unavailable
+
+--- Testing creation for which the node would need to grow ---
+qemu-img: TEST_DIR/t.IMGFMT: Could not resize image: Image format driver does not support resize
+Formatting 'TEST_DIR/t.IMGFMT', fmt=qcow2 size=67108864 preallocation=metadata
+*** done

tests/qemu-iotests/279

@@ -38,6 +38,8 @@ trap "_cleanup; exit \$status" 0 1 2 3 15
 _supported_fmt qcow qcow2 vmdk qed
 _supported_proto file
 _supported_os Linux
+_unsupported_imgopts "subformat=monolithicFlat" \
+                     "subformat=twoGbMaxExtentFlat" \
 
 TEST_IMG="$TEST_IMG.base" _make_test_img 64M
 TEST_IMG="$TEST_IMG.mid" _make_test_img -b "$TEST_IMG.base"
@@ -45,11 +47,12 @@ _make_test_img -b "$TEST_IMG.mid"
 
 echo
 echo '== qemu-img info --backing-chain =='
-_img_info --backing-chain | _filter_img_info
+_img_info --backing-chain | _filter_img_info | grep -v 'backing file format'
 
 echo
 echo '== qemu-img info --backing-chain --image-opts =='
-TEST_IMG="driver=qcow2,file.driver=file,file.filename=$TEST_IMG" _img_info --backing-chain --image-opts | _filter_img_info
+TEST_IMG="driver=$IMGFMT,file.driver=file,file.filename=$TEST_IMG" _img_info --backing-chain --image-opts \
+    | _filter_img_info | grep -v 'backing file format'
 
 # success, all done
 echo "*** done"

tests/qemu-iotests/284

+#!/usr/bin/env bash
+#
+# Test ref count checks on encrypted images
+#
+# Copyright (C) 2019 Red Hat, Inc.
+#
+# 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=berrange@redhat.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+status=1        # failure is the default!
+
+_cleanup()
+{
+        _cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt qcow2
+_supported_proto generic
+_supported_os Linux
+
+
+size=1M
+
+SECRET="secret,id=sec0,data=astrochicken"
+
+IMGSPEC="driver=$IMGFMT,file.filename=$TEST_IMG,encrypt.key-secret=sec0"
+QEMU_IO_OPTIONS=$QEMU_IO_OPTIONS_NO_FMT
+
+_run_test()
+{
+        IMGOPTSSYNTAX=true
+        OLD_TEST_IMG="$TEST_IMG"
+        TEST_IMG="driver=$IMGFMT,file.filename=$TEST_IMG,encrypt.key-secret=sec0"
+        QEMU_IMG_EXTRA_ARGS="--image-opts --object $SECRET"
+
+        echo
+        echo "== cluster size $csize"
+        echo "== checking image refcounts =="
+        _check_test_img
+
+        echo
+        echo "== writing some data =="
+        $QEMU_IO -c "write -P 0x9 0 1"  $QEMU_IMG_EXTRA_ARGS $TEST_IMG | _filter_qemu_io | _filter_testdir
+        echo
+        echo "== rechecking image refcounts =="
+        _check_test_img
+
+        echo
+        echo "== writing some more data =="
+        $QEMU_IO -c "write -P 0x9 $csize 1" $QEMU_IMG_EXTRA_ARGS $TEST_IMG | _filter_qemu_io | _filter_testdir
+        echo
+        echo "== rechecking image refcounts =="
+        _check_test_img
+
+        TEST_IMG="$OLD_TEST_IMG"
+        QEMU_IMG_EXTRA_ARGS=
+        IMGOPTSSYNTAX=
+}
+
+
+echo
+echo "testing LUKS qcow2 encryption"
+echo
+
+for csize in 512 2048 32768
+do
+  _make_test_img --object $SECRET -o "encrypt.format=luks,encrypt.key-secret=sec0,encrypt.iter-time=10,cluster_size=$csize" $size
+  _run_test
+  _cleanup_test_img
+done
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0

tests/qemu-iotests/284.out

+QA output created by 284
+
+testing LUKS qcow2 encryption
+
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576 encrypt.format=luks encrypt.key-secret=sec0 encrypt.iter-time=10
+
+== cluster size 512
+== checking image refcounts ==
+No errors were found on the image.
+
+== writing some data ==
+wrote 1/1 bytes at offset 0
+1 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== rechecking image refcounts ==
+No errors were found on the image.
+
+== writing some more data ==
+wrote 1/1 bytes at offset 512
+1 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== rechecking image refcounts ==
+No errors were found on the image.
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576 encrypt.format=luks encrypt.key-secret=sec0 encrypt.iter-time=10
+
+== cluster size 2048
+== checking image refcounts ==
+No errors were found on the image.
+
+== writing some data ==
+wrote 1/1 bytes at offset 0
+1 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== rechecking image refcounts ==
+No errors were found on the image.
+
+== writing some more data ==
+wrote 1/1 bytes at offset 2048
+1 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== rechecking image refcounts ==
+No errors were found on the image.
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576 encrypt.format=luks encrypt.key-secret=sec0 encrypt.iter-time=10
+
+== cluster size 32768
+== checking image refcounts ==
+No errors were found on the image.
+
+== writing some data ==
+wrote 1/1 bytes at offset 0
+1 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== rechecking image refcounts ==
+No errors were found on the image.
+
+== writing some more data ==
+wrote 1/1 bytes at offset 32768
+1 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+
+== rechecking image refcounts ==
+No errors were found on the image.
+*** done

tests/qemu-iotests/286

+#!/usr/bin/env bash
+#
+# Test qemu-img snapshot -l
+#
+# Copyright (C) 2019 Red Hat, Inc.
+#
+# 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/>.
+#
+
+seq=$(basename "$0")
+echo "QA output created by $seq"
+
+status=1	# failure is the default!
+
+_cleanup()
+{
+    _cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+. ./common.qemu
+
+_supported_fmt qcow2
+_supported_proto file
+# Internal snapshots are (currently) impossible with refcount_bits=1,
+# and generally impossible with external data files
+_unsupported_imgopts 'refcount_bits=1[^0-9]' data_file
+
+_make_test_img 64M
+
+# Should be so long as to take up the whole field width
+sn_name=abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz
+
+# More memory will give us a larger VM state, i.e. one above 1 MB.
+# This way, we get a number with a decimal point.
+qemu_comm_method=monitor _launch_qemu -m 512 "$TEST_IMG"
+
+_send_qemu_cmd $QEMU_HANDLE "savevm $sn_name" '(qemu)'
+_send_qemu_cmd $QEMU_HANDLE 'quit' '(qemu)'
+wait=yes _cleanup_qemu
+
+# Check that all fields are separated by spaces.
+# We first collapse all space sequences into one space each;
+# then we turn every space-separated field into a '.';
+# and finally, we name the '.'s so the output is not just a confusing
+# sequence of dots.
+
+echo 'Output structure:'
+$QEMU_IMG snapshot -l "$TEST_IMG" | tail -n 1 | tr -s ' ' \
+    | sed -e 's/\S\+/./g' \
+    | sed -e 's/\./(snapshot ID)/' \
+          -e 's/\./(snapshot name)/' \
+          -e 's/\./(VM state size value)/' \
+          -e 's/\./(VM state size unit)/' \
+          -e 's/\./(snapshot date)/' \
+          -e 's/\./(snapshot time)/' \
+          -e 's/\./(VM clock)/'
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0

tests/qemu-iotests/286.out

+QA output created by 286
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
+QEMU X.Y.Z monitor - type 'help' for more information
+(qemu) savevm abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz
+(qemu) quit
+Output structure:
+(snapshot ID) (snapshot name) (VM state size value) (VM state size unit) (snapshot date) (snapshot time) (VM clock)
+*** done

tests/qemu-iotests/group

@@ -273,6 +273,7 @@
 256 rw auto quick
 257 rw
 258 rw quick
+259 rw auto quick
 260 rw quick
 261 rw
 262 rw quick migration
@@ -290,3 +291,5 @@
 280 rw migration quick
 281 rw quick
 283 auto quick
+284 rw
+286 rw quick