X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;ds=sidebyside;f=qemu%2Fblockdev.c;h=f1f520a2653baed5a9df4b0b223f9141a303c6dc;hb=437fd90c0250dee670290f9b714253671a990160;hp=62a4586cd65dccce85a384f4c94cba6af79233b4;hpb=5bbd6fe9b8bab2a93e548c5a53b032d1939eec05;p=kvmfornfv.git

diff --git a/qemu/blockdev.c b/qemu/blockdev.c
index 62a4586cd..f1f520a26 100644
--- a/qemu/blockdev.c
+++ b/qemu/blockdev.c
@@ -30,6 +30,7 @@
  * THE SOFTWARE.
  */
 
+#include "qemu/osdep.h"
 #include "sysemu/block-backend.h"
 #include "sysemu/blockdev.h"
 #include "hw/block/block.h"
@@ -49,6 +50,11 @@
 #include "qmp-commands.h"
 #include "trace.h"
 #include "sysemu/arch_init.h"
+#include "qemu/cutils.h"
+#include "qemu/help_option.h"
+
+static QTAILQ_HEAD(, BlockDriverState) monitor_bdrv_states =
+    QTAILQ_HEAD_INITIALIZER(monitor_bdrv_states);
 
 static const char *const if_name[IF_COUNT] = {
     [IF_NONE] = "none",
@@ -124,14 +130,16 @@ void blockdev_mark_auto_del(BlockBackend *blk)
         return;
     }
 
-    aio_context = bdrv_get_aio_context(bs);
-    aio_context_acquire(aio_context);
+    if (bs) {
+        aio_context = bdrv_get_aio_context(bs);
+        aio_context_acquire(aio_context);
 
-    if (bs->job) {
-        block_job_cancel(bs->job);
-    }
+        if (bs->job) {
+            block_job_cancel(bs->job);
+        }
 
-    aio_context_release(aio_context);
+        aio_context_release(aio_context);
+    }
 
     dinfo->auto_del = 1;
 }
@@ -141,6 +149,7 @@ void blockdev_auto_del(BlockBackend *blk)
     DriveInfo *dinfo = blk_legacy_dinfo(blk);
 
     if (dinfo && dinfo->auto_del) {
+        monitor_remove_blk(blk);
         blk_unref(blk);
     }
 }
@@ -229,8 +238,8 @@ bool drive_check_orphaned(void)
             dinfo->type != IF_NONE) {
             fprintf(stderr, "Warning: Orphaned drive without device: "
                     "id=%s,file=%s,if=%s,bus=%d,unit=%d\n",
-                    blk_name(blk), blk_bs(blk)->filename, if_name[dinfo->type],
-                    dinfo->bus, dinfo->unit);
+                    blk_name(blk), blk_bs(blk) ? blk_bs(blk)->filename : "",
+                    if_name[dinfo->type], dinfo->bus, dinfo->unit);
             rs = true;
         }
     }
@@ -281,32 +290,6 @@ typedef struct {
     BlockDriverState *bs;
 } BDRVPutRefBH;
 
-static void bdrv_put_ref_bh(void *opaque)
-{
-    BDRVPutRefBH *s = opaque;
-
-    bdrv_unref(s->bs);
-    qemu_bh_delete(s->bh);
-    g_free(s);
-}
-
-/*
- * Release a BDS reference in a BH
- *
- * It is not safe to use bdrv_unref() from a callback function when the callers
- * still need the BlockDriverState.  In such cases we schedule a BH to release
- * the reference.
- */
-static void bdrv_put_ref_bh_schedule(BlockDriverState *bs)
-{
-    BDRVPutRefBH *s;
-
-    s = g_new(BDRVPutRefBH, 1);
-    s->bh = qemu_bh_new(bdrv_put_ref_bh, s);
-    s->bs = bs;
-    qemu_bh_schedule(s->bh);
-}
-
 static int parse_block_error_action(const char *buf, bool is_read, Error **errp)
 {
     if (!strcmp(buf, "ignore")) {
@@ -324,43 +307,181 @@ static int parse_block_error_action(const char *buf, bool is_read, Error **errp)
     }
 }
 
-static bool check_throttle_config(ThrottleConfig *cfg, Error **errp)
+static bool parse_stats_intervals(BlockAcctStats *stats, QList *intervals,
+                                  Error **errp)
 {
-    if (throttle_conflicting(cfg)) {
-        error_setg(errp, "bps/iops/max total values and read/write values"
-                         " cannot be used at the same time");
-        return false;
-    }
+    const QListEntry *entry;
+    for (entry = qlist_first(intervals); entry; entry = qlist_next(entry)) {
+        switch (qobject_type(entry->value)) {
+
+        case QTYPE_QSTRING: {
+            unsigned long long length;
+            const char *str = qstring_get_str(qobject_to_qstring(entry->value));
+            if (parse_uint_full(str, &length, 10) == 0 &&
+                length > 0 && length <= UINT_MAX) {
+                block_acct_add_interval(stats, (unsigned) length);
+            } else {
+                error_setg(errp, "Invalid interval length: %s", str);
+                return false;
+            }
+            break;
+        }
 
-    if (!throttle_is_valid(cfg)) {
-        error_setg(errp, "bps/iops/maxs values must be 0 or greater");
-        return false;
-    }
+        case QTYPE_QINT: {
+            int64_t length = qint_get_int(qobject_to_qint(entry->value));
+            if (length > 0 && length <= UINT_MAX) {
+                block_acct_add_interval(stats, (unsigned) length);
+            } else {
+                error_setg(errp, "Invalid interval length: %" PRId64, length);
+                return false;
+            }
+            break;
+        }
 
+        default:
+            error_setg(errp, "The specification of stats-intervals is invalid");
+            return false;
+        }
+    }
     return true;
 }
 
 typedef enum { MEDIA_DISK, MEDIA_CDROM } DriveMediaType;
 
+/* All parameters but @opts are optional and may be set to NULL. */
+static void extract_common_blockdev_options(QemuOpts *opts, int *bdrv_flags,
+    const char **throttling_group, ThrottleConfig *throttle_cfg,
+    BlockdevDetectZeroesOptions *detect_zeroes, Error **errp)
+{
+    const char *discard;
+    Error *local_error = NULL;
+    const char *aio;
+
+    if (bdrv_flags) {
+        if (!qemu_opt_get_bool(opts, "read-only", false)) {
+            *bdrv_flags |= BDRV_O_RDWR;
+        }
+        if (qemu_opt_get_bool(opts, "copy-on-read", false)) {
+            *bdrv_flags |= BDRV_O_COPY_ON_READ;
+        }
+
+        if ((discard = qemu_opt_get(opts, "discard")) != NULL) {
+            if (bdrv_parse_discard_flags(discard, bdrv_flags) != 0) {
+                error_setg(errp, "Invalid discard option");
+                return;
+            }
+        }
+
+        if ((aio = qemu_opt_get(opts, "aio")) != NULL) {
+            if (!strcmp(aio, "native")) {
+                *bdrv_flags |= BDRV_O_NATIVE_AIO;
+            } else if (!strcmp(aio, "threads")) {
+                /* this is the default */
+            } else {
+               error_setg(errp, "invalid aio option");
+               return;
+            }
+        }
+    }
+
+    /* disk I/O throttling */
+    if (throttling_group) {
+        *throttling_group = qemu_opt_get(opts, "throttling.group");
+    }
+
+    if (throttle_cfg) {
+        throttle_config_init(throttle_cfg);
+        throttle_cfg->buckets[THROTTLE_BPS_TOTAL].avg =
+            qemu_opt_get_number(opts, "throttling.bps-total", 0);
+        throttle_cfg->buckets[THROTTLE_BPS_READ].avg  =
+            qemu_opt_get_number(opts, "throttling.bps-read", 0);
+        throttle_cfg->buckets[THROTTLE_BPS_WRITE].avg =
+            qemu_opt_get_number(opts, "throttling.bps-write", 0);
+        throttle_cfg->buckets[THROTTLE_OPS_TOTAL].avg =
+            qemu_opt_get_number(opts, "throttling.iops-total", 0);
+        throttle_cfg->buckets[THROTTLE_OPS_READ].avg =
+            qemu_opt_get_number(opts, "throttling.iops-read", 0);
+        throttle_cfg->buckets[THROTTLE_OPS_WRITE].avg =
+            qemu_opt_get_number(opts, "throttling.iops-write", 0);
+
+        throttle_cfg->buckets[THROTTLE_BPS_TOTAL].max =
+            qemu_opt_get_number(opts, "throttling.bps-total-max", 0);
+        throttle_cfg->buckets[THROTTLE_BPS_READ].max  =
+            qemu_opt_get_number(opts, "throttling.bps-read-max", 0);
+        throttle_cfg->buckets[THROTTLE_BPS_WRITE].max =
+            qemu_opt_get_number(opts, "throttling.bps-write-max", 0);
+        throttle_cfg->buckets[THROTTLE_OPS_TOTAL].max =
+            qemu_opt_get_number(opts, "throttling.iops-total-max", 0);
+        throttle_cfg->buckets[THROTTLE_OPS_READ].max =
+            qemu_opt_get_number(opts, "throttling.iops-read-max", 0);
+        throttle_cfg->buckets[THROTTLE_OPS_WRITE].max =
+            qemu_opt_get_number(opts, "throttling.iops-write-max", 0);
+
+        throttle_cfg->buckets[THROTTLE_BPS_TOTAL].burst_length =
+            qemu_opt_get_number(opts, "throttling.bps-total-max-length", 1);
+        throttle_cfg->buckets[THROTTLE_BPS_READ].burst_length  =
+            qemu_opt_get_number(opts, "throttling.bps-read-max-length", 1);
+        throttle_cfg->buckets[THROTTLE_BPS_WRITE].burst_length =
+            qemu_opt_get_number(opts, "throttling.bps-write-max-length", 1);
+        throttle_cfg->buckets[THROTTLE_OPS_TOTAL].burst_length =
+            qemu_opt_get_number(opts, "throttling.iops-total-max-length", 1);
+        throttle_cfg->buckets[THROTTLE_OPS_READ].burst_length =
+            qemu_opt_get_number(opts, "throttling.iops-read-max-length", 1);
+        throttle_cfg->buckets[THROTTLE_OPS_WRITE].burst_length =
+            qemu_opt_get_number(opts, "throttling.iops-write-max-length", 1);
+
+        throttle_cfg->op_size =
+            qemu_opt_get_number(opts, "throttling.iops-size", 0);
+
+        if (!throttle_is_valid(throttle_cfg, errp)) {
+            return;
+        }
+    }
+
+    if (detect_zeroes) {
+        *detect_zeroes =
+            qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
+                            qemu_opt_get(opts, "detect-zeroes"),
+                            BLOCKDEV_DETECT_ZEROES_OPTIONS__MAX,
+                            BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
+                            &local_error);
+        if (local_error) {
+            error_propagate(errp, local_error);
+            return;
+        }
+
+        if (bdrv_flags &&
+            *detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
+            !(*bdrv_flags & BDRV_O_UNMAP))
+        {
+            error_setg(errp, "setting detect-zeroes to unmap is not allowed "
+                             "without setting discard operation to unmap");
+            return;
+        }
+    }
+}
+
 /* Takes the ownership of bs_opts */
 static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
                                    Error **errp)
 {
     const char *buf;
-    int ro = 0;
     int bdrv_flags = 0;
     int on_read_error, on_write_error;
+    bool account_invalid, account_failed;
+    bool writethrough;
     BlockBackend *blk;
     BlockDriverState *bs;
     ThrottleConfig cfg;
     int snapshot = 0;
-    bool copy_on_read;
     Error *error = NULL;
     QemuOpts *opts;
+    QDict *interval_dict = NULL;
+    QList *interval_list = NULL;
     const char *id;
-    bool has_driver_specific_opts;
-    BlockdevDetectZeroesOptions detect_zeroes;
-    const char *throttling_group;
+    BlockdevDetectZeroesOptions detect_zeroes =
+        BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
+    const char *throttling_group = NULL;
 
     /* Check common options by copying from bs_opts to opts, all other options
      * stay in bs_opts for processing by bdrv_open(). */
@@ -381,42 +502,29 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
         qdict_del(bs_opts, "id");
     }
 
-    has_driver_specific_opts = !!qdict_size(bs_opts);
-
     /* extract parameters */
     snapshot = qemu_opt_get_bool(opts, "snapshot", 0);
-    ro = qemu_opt_get_bool(opts, "read-only", 0);
-    copy_on_read = qemu_opt_get_bool(opts, "copy-on-read", false);
 
-    if ((buf = qemu_opt_get(opts, "discard")) != NULL) {
-        if (bdrv_parse_discard_flags(buf, &bdrv_flags) != 0) {
-            error_setg(errp, "invalid discard option");
-            goto early_err;
-        }
-    }
+    account_invalid = qemu_opt_get_bool(opts, "stats-account-invalid", true);
+    account_failed = qemu_opt_get_bool(opts, "stats-account-failed", true);
 
-    if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_WB, true)) {
-        bdrv_flags |= BDRV_O_CACHE_WB;
-    }
-    if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_DIRECT, false)) {
-        bdrv_flags |= BDRV_O_NOCACHE;
-    }
-    if (qemu_opt_get_bool(opts, BDRV_OPT_CACHE_NO_FLUSH, false)) {
-        bdrv_flags |= BDRV_O_NO_FLUSH;
+    writethrough = !qemu_opt_get_bool(opts, BDRV_OPT_CACHE_WB, true);
+
+    qdict_extract_subqdict(bs_opts, &interval_dict, "stats-intervals.");
+    qdict_array_split(interval_dict, &interval_list);
+
+    if (qdict_size(interval_dict) != 0) {
+        error_setg(errp, "Invalid option stats-intervals.%s",
+                   qdict_first(interval_dict)->key);
+        goto early_err;
     }
 
-#ifdef CONFIG_LINUX_AIO
-    if ((buf = qemu_opt_get(opts, "aio")) != NULL) {
-        if (!strcmp(buf, "native")) {
-            bdrv_flags |= BDRV_O_NATIVE_AIO;
-        } else if (!strcmp(buf, "threads")) {
-            /* this is the default */
-        } else {
-           error_setg(errp, "invalid aio option");
-           goto early_err;
-        }
+    extract_common_blockdev_options(opts, &bdrv_flags, &throttling_group, &cfg,
+                                    &detect_zeroes, &error);
+    if (error) {
+        error_propagate(errp, error);
+        goto early_err;
     }
-#endif
 
     if ((buf = qemu_opt_get(opts, "format")) != NULL) {
         if (is_help_option(buf)) {
@@ -433,43 +541,6 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
         qdict_put(bs_opts, "driver", qstring_from_str(buf));
     }
 
-    /* disk I/O throttling */
-    memset(&cfg, 0, sizeof(cfg));
-    cfg.buckets[THROTTLE_BPS_TOTAL].avg =
-        qemu_opt_get_number(opts, "throttling.bps-total", 0);
-    cfg.buckets[THROTTLE_BPS_READ].avg  =
-        qemu_opt_get_number(opts, "throttling.bps-read", 0);
-    cfg.buckets[THROTTLE_BPS_WRITE].avg =
-        qemu_opt_get_number(opts, "throttling.bps-write", 0);
-    cfg.buckets[THROTTLE_OPS_TOTAL].avg =
-        qemu_opt_get_number(opts, "throttling.iops-total", 0);
-    cfg.buckets[THROTTLE_OPS_READ].avg =
-        qemu_opt_get_number(opts, "throttling.iops-read", 0);
-    cfg.buckets[THROTTLE_OPS_WRITE].avg =
-        qemu_opt_get_number(opts, "throttling.iops-write", 0);
-
-    cfg.buckets[THROTTLE_BPS_TOTAL].max =
-        qemu_opt_get_number(opts, "throttling.bps-total-max", 0);
-    cfg.buckets[THROTTLE_BPS_READ].max  =
-        qemu_opt_get_number(opts, "throttling.bps-read-max", 0);
-    cfg.buckets[THROTTLE_BPS_WRITE].max =
-        qemu_opt_get_number(opts, "throttling.bps-write-max", 0);
-    cfg.buckets[THROTTLE_OPS_TOTAL].max =
-        qemu_opt_get_number(opts, "throttling.iops-total-max", 0);
-    cfg.buckets[THROTTLE_OPS_READ].max =
-        qemu_opt_get_number(opts, "throttling.iops-read-max", 0);
-    cfg.buckets[THROTTLE_OPS_WRITE].max =
-        qemu_opt_get_number(opts, "throttling.iops-write-max", 0);
-
-    cfg.op_size = qemu_opt_get_number(opts, "throttling.iops-size", 0);
-
-    throttling_group = qemu_opt_get(opts, "throttling.group");
-
-    if (!check_throttle_config(&cfg, &error)) {
-        error_propagate(errp, error);
-        goto early_err;
-    }
-
     on_write_error = BLOCKDEV_ON_ERROR_ENOSPC;
     if ((buf = qemu_opt_get(opts, "werror")) != NULL) {
         on_write_error = parse_block_error_action(buf, 0, &error);
@@ -488,34 +559,32 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
         }
     }
 
-    detect_zeroes =
-        qapi_enum_parse(BlockdevDetectZeroesOptions_lookup,
-                        qemu_opt_get(opts, "detect-zeroes"),
-                        BLOCKDEV_DETECT_ZEROES_OPTIONS_MAX,
-                        BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF,
-                        &error);
-    if (error) {
-        error_propagate(errp, error);
-        goto early_err;
-    }
-
-    if (detect_zeroes == BLOCKDEV_DETECT_ZEROES_OPTIONS_UNMAP &&
-        !(bdrv_flags & BDRV_O_UNMAP)) {
-        error_setg(errp, "setting detect-zeroes to unmap is not allowed "
-                         "without setting discard operation to unmap");
-        goto early_err;
+    if (snapshot) {
+        bdrv_flags |= BDRV_O_SNAPSHOT;
     }
 
     /* init */
-    if ((!file || !*file) && !has_driver_specific_opts) {
-        blk = blk_new_with_bs(qemu_opts_id(opts), errp);
+    if ((!file || !*file) && !qdict_size(bs_opts)) {
+        BlockBackendRootState *blk_rs;
+
+        blk = blk_new(errp);
         if (!blk) {
             goto early_err;
         }
 
-        bs = blk_bs(blk);
-        bs->open_flags = snapshot ? BDRV_O_SNAPSHOT : 0;
-        bs->read_only = ro;
+        blk_rs = blk_get_root_state(blk);
+        blk_rs->open_flags    = bdrv_flags;
+        blk_rs->read_only     = !(bdrv_flags & BDRV_O_RDWR);
+        blk_rs->detect_zeroes = detect_zeroes;
+
+        if (throttle_enabled(&cfg)) {
+            if (!throttling_group) {
+                throttling_group = blk_name(blk);
+            }
+            blk_rs->throttle_group = g_strdup(throttling_group);
+            blk_rs->throttle_state = throttle_group_incref(throttling_group);
+            blk_rs->throttle_state->cfg = cfg;
+        }
 
         QDECREF(bs_opts);
     } else {
@@ -523,58 +592,149 @@ static BlockBackend *blockdev_init(const char *file, QDict *bs_opts,
             file = NULL;
         }
 
-        if (snapshot) {
-            /* always use cache=unsafe with snapshot */
-            bdrv_flags &= ~BDRV_O_CACHE_MASK;
-            bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB|BDRV_O_NO_FLUSH);
-        }
-
-        if (copy_on_read) {
-            bdrv_flags |= BDRV_O_COPY_ON_READ;
-        }
+        /* bdrv_open() defaults to the values in bdrv_flags (for compatibility
+         * with other callers) rather than what we want as the real defaults.
+         * Apply the defaults here instead. */
+        qdict_set_default_str(bs_opts, BDRV_OPT_CACHE_DIRECT, "off");
+        qdict_set_default_str(bs_opts, BDRV_OPT_CACHE_NO_FLUSH, "off");
+        assert((bdrv_flags & BDRV_O_CACHE_MASK) == 0);
 
         if (runstate_check(RUN_STATE_INMIGRATE)) {
-            bdrv_flags |= BDRV_O_INCOMING;
+            bdrv_flags |= BDRV_O_INACTIVE;
         }
 
-        bdrv_flags |= ro ? 0 : BDRV_O_RDWR;
-
-        blk = blk_new_open(qemu_opts_id(opts), file, NULL, bs_opts, bdrv_flags,
-                           errp);
+        blk = blk_new_open(file, NULL, bs_opts, bdrv_flags, errp);
         if (!blk) {
             goto err_no_bs_opts;
         }
         bs = blk_bs(blk);
-    }
 
-    bs->detect_zeroes = detect_zeroes;
+        bs->detect_zeroes = detect_zeroes;
 
-    bdrv_set_on_error(bs, on_read_error, on_write_error);
+        /* disk I/O throttling */
+        if (throttle_enabled(&cfg)) {
+            if (!throttling_group) {
+                throttling_group = blk_name(blk);
+            }
+            bdrv_io_limits_enable(bs, throttling_group);
+            bdrv_set_io_limits(bs, &cfg);
+        }
 
-    /* disk I/O throttling */
-    if (throttle_enabled(&cfg)) {
-        if (!throttling_group) {
-            throttling_group = blk_name(blk);
+        if (bdrv_key_required(bs)) {
+            autostart = 0;
+        }
+
+        block_acct_init(blk_get_stats(blk), account_invalid, account_failed);
+
+        if (!parse_stats_intervals(blk_get_stats(blk), interval_list, errp)) {
+            blk_unref(blk);
+            blk = NULL;
+            goto err_no_bs_opts;
         }
-        bdrv_io_limits_enable(bs, throttling_group);
-        bdrv_set_io_limits(bs, &cfg);
     }
 
-    if (bdrv_key_required(bs)) {
-        autostart = 0;
+    blk_set_enable_write_cache(blk, !writethrough);
+    blk_set_on_error(blk, on_read_error, on_write_error);
+
+    if (!monitor_add_blk(blk, qemu_opts_id(opts), errp)) {
+        blk_unref(blk);
+        blk = NULL;
+        goto err_no_bs_opts;
     }
 
 err_no_bs_opts:
     qemu_opts_del(opts);
+    QDECREF(interval_dict);
+    QDECREF(interval_list);
     return blk;
 
 early_err:
     qemu_opts_del(opts);
+    QDECREF(interval_dict);
+    QDECREF(interval_list);
 err_no_opts:
     QDECREF(bs_opts);
     return NULL;
 }
 
+static QemuOptsList qemu_root_bds_opts;
+
+/* Takes the ownership of bs_opts */
+static BlockDriverState *bds_tree_init(QDict *bs_opts, Error **errp)
+{
+    BlockDriverState *bs;
+    QemuOpts *opts;
+    Error *local_error = NULL;
+    BlockdevDetectZeroesOptions detect_zeroes;
+    int ret;
+    int bdrv_flags = 0;
+
+    opts = qemu_opts_create(&qemu_root_bds_opts, NULL, 1, errp);
+    if (!opts) {
+        goto fail;
+    }
+
+    qemu_opts_absorb_qdict(opts, bs_opts, &local_error);
+    if (local_error) {
+        error_propagate(errp, local_error);
+        goto fail;
+    }
+
+    extract_common_blockdev_options(opts, &bdrv_flags, NULL, NULL,
+                                    &detect_zeroes, &local_error);
+    if (local_error) {
+        error_propagate(errp, local_error);
+        goto fail;
+    }
+
+    /* bdrv_open() defaults to the values in bdrv_flags (for compatibility
+     * with other callers) rather than what we want as the real defaults.
+     * Apply the defaults here instead. */
+    qdict_set_default_str(bs_opts, BDRV_OPT_CACHE_DIRECT, "off");
+    qdict_set_default_str(bs_opts, BDRV_OPT_CACHE_NO_FLUSH, "off");
+
+    if (runstate_check(RUN_STATE_INMIGRATE)) {
+        bdrv_flags |= BDRV_O_INACTIVE;
+    }
+
+    bs = NULL;
+    ret = bdrv_open(&bs, NULL, NULL, bs_opts, bdrv_flags, errp);
+    if (ret < 0) {
+        goto fail_no_bs_opts;
+    }
+
+    bs->detect_zeroes = detect_zeroes;
+
+fail_no_bs_opts:
+    qemu_opts_del(opts);
+    return bs;
+
+fail:
+    qemu_opts_del(opts);
+    QDECREF(bs_opts);
+    return NULL;
+}
+
+void blockdev_close_all_bdrv_states(void)
+{
+    BlockDriverState *bs, *next_bs;
+
+    QTAILQ_FOREACH_SAFE(bs, &monitor_bdrv_states, monitor_list, next_bs) {
+        AioContext *ctx = bdrv_get_aio_context(bs);
+
+        aio_context_acquire(ctx);
+        bdrv_unref(bs);
+        aio_context_release(ctx);
+    }
+}
+
+/* Iterates over the list of monitor-owned BlockDriverStates */
+BlockDriverState *bdrv_next_monitor_owned(BlockDriverState *bs)
+{
+    return bs ? QTAILQ_NEXT(bs, monitor_list)
+              : QTAILQ_FIRST(&monitor_bdrv_states);
+}
+
 static void qemu_opt_rename(QemuOpts *opts, const char *from, const char *to,
                             Error **errp)
 {
@@ -737,8 +897,9 @@ DriveInfo *drive_new(QemuOpts *all_opts, BlockInterfaceType block_default_type)
     value = qemu_opt_get(all_opts, "cache");
     if (value) {
         int flags = 0;
+        bool writethrough;
 
-        if (bdrv_parse_cache_flags(value, &flags) != 0) {
+        if (bdrv_parse_cache_mode(value, &flags, &writethrough) != 0) {
             error_report("invalid cache option");
             return NULL;
         }
@@ -746,7 +907,7 @@ DriveInfo *drive_new(QemuOpts *all_opts, BlockInterfaceType block_default_type)
         /* Specific options take precedence */
         if (!qemu_opt_get(all_opts, BDRV_OPT_CACHE_WB)) {
             qemu_opt_set_bool(all_opts, BDRV_OPT_CACHE_WB,
-                              !!(flags & BDRV_O_CACHE_WB), &error_abort);
+                              !writethrough, &error_abort);
         }
         if (!qemu_opt_get(all_opts, BDRV_OPT_CACHE_DIRECT)) {
             qemu_opt_set_bool(all_opts, BDRV_OPT_CACHE_DIRECT,
@@ -1031,14 +1192,28 @@ void hmp_commit(Monitor *mon, const QDict *qdict)
     int ret;
 
     if (!strcmp(device, "all")) {
-        ret = bdrv_commit_all();
+        ret = blk_commit_all();
     } else {
+        BlockDriverState *bs;
+        AioContext *aio_context;
+
         blk = blk_by_name(device);
         if (!blk) {
             monitor_printf(mon, "Device '%s' not found\n", device);
             return;
         }
-        ret = bdrv_commit(blk_bs(blk));
+        if (!blk_is_available(blk)) {
+            monitor_printf(mon, "Device '%s' has no medium\n", device);
+            return;
+        }
+
+        bs = blk_bs(blk);
+        aio_context = bdrv_get_aio_context(bs);
+        aio_context_acquire(aio_context);
+
+        ret = bdrv_commit(bs);
+
+        aio_context_release(aio_context);
     }
     if (ret < 0) {
         monitor_printf(mon, "'commit' error for '%s': %s\n", device,
@@ -1046,16 +1221,13 @@ void hmp_commit(Monitor *mon, const QDict *qdict)
     }
 }
 
-static void blockdev_do_action(int kind, void *data, Error **errp)
+static void blockdev_do_action(TransactionAction *action, Error **errp)
 {
-    TransactionAction action;
     TransactionActionList list;
 
-    action.kind = kind;
-    action.data = data;
-    list.value = &action;
+    list.value = action;
     list.next = NULL;
-    qmp_transaction(&list, errp);
+    qmp_transaction(&list, false, NULL, errp);
 }
 
 void qmp_blockdev_snapshot_sync(bool has_device, const char *device,
@@ -1066,7 +1238,7 @@ void qmp_blockdev_snapshot_sync(bool has_device, const char *device,
                                 bool has_format, const char *format,
                                 bool has_mode, NewImageMode mode, Error **errp)
 {
-    BlockdevSnapshot snapshot = {
+    BlockdevSnapshotSync snapshot = {
         .has_device = has_device,
         .device = (char *) device,
         .has_node_name = has_node_name,
@@ -1079,8 +1251,25 @@ void qmp_blockdev_snapshot_sync(bool has_device, const char *device,
         .has_mode = has_mode,
         .mode = mode,
     };
-    blockdev_do_action(TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC,
-                       &snapshot, errp);
+    TransactionAction action = {
+        .type = TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC,
+        .u.blockdev_snapshot_sync.data = &snapshot,
+    };
+    blockdev_do_action(&action, errp);
+}
+
+void qmp_blockdev_snapshot(const char *node, const char *overlay,
+                           Error **errp)
+{
+    BlockdevSnapshot snapshot_data = {
+        .node = (char *) node,
+        .overlay = (char *) overlay
+    };
+    TransactionAction action = {
+        .type = TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT,
+        .u.blockdev_snapshot.data = &snapshot_data,
+    };
+    blockdev_do_action(&action, errp);
 }
 
 void qmp_blockdev_snapshot_internal_sync(const char *device,
@@ -1091,9 +1280,11 @@ void qmp_blockdev_snapshot_internal_sync(const char *device,
         .device = (char *) device,
         .name = (char *) name
     };
-
-    blockdev_do_action(TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_INTERNAL_SYNC,
-                       &snapshot, errp);
+    TransactionAction action = {
+        .type = TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_INTERNAL_SYNC,
+        .u.blockdev_snapshot_internal_sync.data = &snapshot,
+    };
+    blockdev_do_action(&action, errp);
 }
 
 SnapshotInfo *qmp_blockdev_snapshot_delete_internal_sync(const char *device,
@@ -1117,7 +1308,9 @@ SnapshotInfo *qmp_blockdev_snapshot_delete_internal_sync(const char *device,
                   "Device '%s' not found", device);
         return NULL;
     }
-    bs = blk_bs(blk);
+
+    aio_context = blk_get_aio_context(blk);
+    aio_context_acquire(aio_context);
 
     if (!has_id) {
         id = NULL;
@@ -1129,11 +1322,14 @@ SnapshotInfo *qmp_blockdev_snapshot_delete_internal_sync(const char *device,
 
     if (!id && !name) {
         error_setg(errp, "Name or id must be provided");
-        return NULL;
+        goto out_aio_context;
     }
 
-    aio_context = bdrv_get_aio_context(bs);
-    aio_context_acquire(aio_context);
+    if (!blk_is_available(blk)) {
+        error_setg(errp, "Device '%s' has no medium", device);
+        goto out_aio_context;
+    }
+    bs = blk_bs(blk);
 
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE, errp)) {
         goto out_aio_context;
@@ -1240,43 +1436,75 @@ static BdrvDirtyBitmap *block_dirty_bitmap_lookup(const char *node,
 
 /* New and old BlockDriverState structs for atomic group operations */
 
-typedef struct BlkTransactionState BlkTransactionState;
+typedef struct BlkActionState BlkActionState;
 
-/* Only prepare() may fail. In a single transaction, only one of commit() or
-   abort() will be called, clean() will always be called if it present. */
-typedef struct BdrvActionOps {
-    /* Size of state struct, in bytes. */
+/**
+ * BlkActionOps:
+ * Table of operations that define an Action.
+ *
+ * @instance_size: Size of state struct, in bytes.
+ * @prepare: Prepare the work, must NOT be NULL.
+ * @commit: Commit the changes, can be NULL.
+ * @abort: Abort the changes on fail, can be NULL.
+ * @clean: Clean up resources after all transaction actions have called
+ *         commit() or abort(). Can be NULL.
+ *
+ * Only prepare() may fail. In a single transaction, only one of commit() or
+ * abort() will be called. clean() will always be called if it is present.
+ */
+typedef struct BlkActionOps {
     size_t instance_size;
-    /* Prepare the work, must NOT be NULL. */
-    void (*prepare)(BlkTransactionState *common, Error **errp);
-    /* Commit the changes, can be NULL. */
-    void (*commit)(BlkTransactionState *common);
-    /* Abort the changes on fail, can be NULL. */
-    void (*abort)(BlkTransactionState *common);
-    /* Clean up resource in the end, can be NULL. */
-    void (*clean)(BlkTransactionState *common);
-} BdrvActionOps;
+    void (*prepare)(BlkActionState *common, Error **errp);
+    void (*commit)(BlkActionState *common);
+    void (*abort)(BlkActionState *common);
+    void (*clean)(BlkActionState *common);
+} BlkActionOps;
 
-/*
- * This structure must be arranged as first member in child type, assuming
- * that compiler will also arrange it to the same address with parent instance.
- * Later it will be used in free().
+/**
+ * BlkActionState:
+ * Describes one Action's state within a Transaction.
+ *
+ * @action: QAPI-defined enum identifying which Action to perform.
+ * @ops: Table of ActionOps this Action can perform.
+ * @block_job_txn: Transaction which this action belongs to.
+ * @entry: List membership for all Actions in this Transaction.
+ *
+ * This structure must be arranged as first member in a subclassed type,
+ * assuming that the compiler will also arrange it to the same offsets as the
+ * base class.
  */
-struct BlkTransactionState {
+struct BlkActionState {
     TransactionAction *action;
-    const BdrvActionOps *ops;
-    QSIMPLEQ_ENTRY(BlkTransactionState) entry;
+    const BlkActionOps *ops;
+    BlockJobTxn *block_job_txn;
+    TransactionProperties *txn_props;
+    QSIMPLEQ_ENTRY(BlkActionState) entry;
 };
 
 /* internal snapshot private data */
 typedef struct InternalSnapshotState {
-    BlkTransactionState common;
+    BlkActionState common;
     BlockDriverState *bs;
     AioContext *aio_context;
     QEMUSnapshotInfo sn;
+    bool created;
 } InternalSnapshotState;
 
-static void internal_snapshot_prepare(BlkTransactionState *common,
+
+static int action_check_completion_mode(BlkActionState *s, Error **errp)
+{
+    if (s->txn_props->completion_mode != ACTION_COMPLETION_MODE_INDIVIDUAL) {
+        error_setg(errp,
+                   "Action '%s' does not support Transaction property "
+                   "completion-mode = %s",
+                   TransactionActionKind_lookup[s->action->type],
+                   ActionCompletionMode_lookup[s->txn_props->completion_mode]);
+        return -1;
+    }
+    return 0;
+}
+
+static void internal_snapshot_prepare(BlkActionState *common,
                                       Error **errp)
 {
     Error *local_err = NULL;
@@ -1291,9 +1519,9 @@ static void internal_snapshot_prepare(BlkTransactionState *common,
     InternalSnapshotState *state;
     int ret1;
 
-    g_assert(common->action->kind ==
+    g_assert(common->action->type ==
              TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_INTERNAL_SYNC);
-    internal = common->action->blockdev_snapshot_internal_sync;
+    internal = common->action->u.blockdev_snapshot_internal_sync.data;
     state = DO_UPCAST(InternalSnapshotState, common, common);
 
     /* 1. parse input */
@@ -1301,22 +1529,29 @@ static void internal_snapshot_prepare(BlkTransactionState *common,
     name = internal->name;
 
     /* 2. check for validation */
+    if (action_check_completion_mode(common, errp) < 0) {
+        return;
+    }
+
     blk = blk_by_name(device);
     if (!blk) {
         error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
                   "Device '%s' not found", device);
         return;
     }
-    bs = blk_bs(blk);
 
     /* AioContext is released in .clean() */
-    state->aio_context = bdrv_get_aio_context(bs);
+    state->aio_context = blk_get_aio_context(blk);
     aio_context_acquire(state->aio_context);
 
-    if (!bdrv_is_inserted(bs)) {
+    if (!blk_is_available(blk)) {
         error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
         return;
     }
+    bs = blk_bs(blk);
+
+    state->bs = bs;
+    bdrv_drained_begin(bs);
 
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_INTERNAL_SNAPSHOT, errp)) {
         return;
@@ -1369,10 +1604,10 @@ static void internal_snapshot_prepare(BlkTransactionState *common,
     }
 
     /* 4. succeed, mark a snapshot is created */
-    state->bs = bs;
+    state->created = true;
 }
 
-static void internal_snapshot_abort(BlkTransactionState *common)
+static void internal_snapshot_abort(BlkActionState *common)
 {
     InternalSnapshotState *state =
                              DO_UPCAST(InternalSnapshotState, common, common);
@@ -1380,106 +1615,96 @@ static void internal_snapshot_abort(BlkTransactionState *common)
     QEMUSnapshotInfo *sn = &state->sn;
     Error *local_error = NULL;
 
-    if (!bs) {
+    if (!state->created) {
         return;
     }
 
     if (bdrv_snapshot_delete(bs, sn->id_str, sn->name, &local_error) < 0) {
-        error_report("Failed to delete snapshot with id '%s' and name '%s' on "
-                     "device '%s' in abort: %s",
-                     sn->id_str,
-                     sn->name,
-                     bdrv_get_device_name(bs),
-                     error_get_pretty(local_error));
-        error_free(local_error);
+        error_reportf_err(local_error,
+                          "Failed to delete snapshot with id '%s' and "
+                          "name '%s' on device '%s' in abort: ",
+                          sn->id_str, sn->name,
+                          bdrv_get_device_name(bs));
     }
 }
 
-static void internal_snapshot_clean(BlkTransactionState *common)
+static void internal_snapshot_clean(BlkActionState *common)
 {
     InternalSnapshotState *state = DO_UPCAST(InternalSnapshotState,
                                              common, common);
 
     if (state->aio_context) {
+        if (state->bs) {
+            bdrv_drained_end(state->bs);
+        }
         aio_context_release(state->aio_context);
     }
 }
 
 /* external snapshot private data */
 typedef struct ExternalSnapshotState {
-    BlkTransactionState common;
+    BlkActionState common;
     BlockDriverState *old_bs;
     BlockDriverState *new_bs;
     AioContext *aio_context;
 } ExternalSnapshotState;
 
-static void external_snapshot_prepare(BlkTransactionState *common,
+static void external_snapshot_prepare(BlkActionState *common,
                                       Error **errp)
 {
-    BlockDriver *drv;
-    int flags, ret;
+    int flags = 0, ret;
     QDict *options = NULL;
     Error *local_err = NULL;
-    bool has_device = false;
+    /* Device and node name of the image to generate the snapshot from */
     const char *device;
-    bool has_node_name = false;
     const char *node_name;
-    bool has_snapshot_node_name = false;
-    const char *snapshot_node_name;
+    /* Reference to the new image (for 'blockdev-snapshot') */
+    const char *snapshot_ref;
+    /* File name of the new image (for 'blockdev-snapshot-sync') */
     const char *new_image_file;
-    const char *format = "qcow2";
-    enum NewImageMode mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
     ExternalSnapshotState *state =
                              DO_UPCAST(ExternalSnapshotState, common, common);
     TransactionAction *action = common->action;
 
-    /* get parameters */
-    g_assert(action->kind == TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC);
-
-    has_device = action->blockdev_snapshot_sync->has_device;
-    device = action->blockdev_snapshot_sync->device;
-    has_node_name = action->blockdev_snapshot_sync->has_node_name;
-    node_name = action->blockdev_snapshot_sync->node_name;
-    has_snapshot_node_name =
-        action->blockdev_snapshot_sync->has_snapshot_node_name;
-    snapshot_node_name = action->blockdev_snapshot_sync->snapshot_node_name;
-
-    new_image_file = action->blockdev_snapshot_sync->snapshot_file;
-    if (action->blockdev_snapshot_sync->has_format) {
-        format = action->blockdev_snapshot_sync->format;
-    }
-    if (action->blockdev_snapshot_sync->has_mode) {
-        mode = action->blockdev_snapshot_sync->mode;
+    /* 'blockdev-snapshot' and 'blockdev-snapshot-sync' have similar
+     * purpose but a different set of parameters */
+    switch (action->type) {
+    case TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT:
+        {
+            BlockdevSnapshot *s = action->u.blockdev_snapshot.data;
+            device = s->node;
+            node_name = s->node;
+            new_image_file = NULL;
+            snapshot_ref = s->overlay;
+        }
+        break;
+    case TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC:
+        {
+            BlockdevSnapshotSync *s = action->u.blockdev_snapshot_sync.data;
+            device = s->has_device ? s->device : NULL;
+            node_name = s->has_node_name ? s->node_name : NULL;
+            new_image_file = s->snapshot_file;
+            snapshot_ref = NULL;
+        }
+        break;
+    default:
+        g_assert_not_reached();
     }
 
     /* start processing */
-    drv = bdrv_find_format(format);
-    if (!drv) {
-        error_setg(errp, QERR_INVALID_BLOCK_FORMAT, format);
-        return;
-    }
-
-    state->old_bs = bdrv_lookup_bs(has_device ? device : NULL,
-                                   has_node_name ? node_name : NULL,
-                                   &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
-        return;
-    }
-
-    if (has_node_name && !has_snapshot_node_name) {
-        error_setg(errp, "New snapshot node name missing");
+    if (action_check_completion_mode(common, errp) < 0) {
         return;
     }
 
-    if (has_snapshot_node_name && bdrv_find_node(snapshot_node_name)) {
-        error_setg(errp, "New snapshot node name already existing");
+    state->old_bs = bdrv_lookup_bs(device, node_name, errp);
+    if (!state->old_bs) {
         return;
     }
 
     /* Acquire AioContext now so any threads operating on old_bs stop */
     state->aio_context = bdrv_get_aio_context(state->old_bs);
     aio_context_acquire(state->aio_context);
+    bdrv_drained_begin(state->old_bs);
 
     if (!bdrv_is_inserted(state->old_bs)) {
         error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
@@ -1503,38 +1728,85 @@ static void external_snapshot_prepare(BlkTransactionState *common,
         return;
     }
 
-    flags = state->old_bs->open_flags;
+    if (action->type == TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC) {
+        BlockdevSnapshotSync *s = action->u.blockdev_snapshot_sync.data;
+        const char *format = s->has_format ? s->format : "qcow2";
+        enum NewImageMode mode;
+        const char *snapshot_node_name =
+            s->has_snapshot_node_name ? s->snapshot_node_name : NULL;
 
-    /* create new image w/backing file */
-    if (mode != NEW_IMAGE_MODE_EXISTING) {
-        bdrv_img_create(new_image_file, format,
-                        state->old_bs->filename,
-                        state->old_bs->drv->format_name,
-                        NULL, -1, flags, &local_err, false);
-        if (local_err) {
-            error_propagate(errp, local_err);
+        if (node_name && !snapshot_node_name) {
+            error_setg(errp, "New snapshot node name missing");
+            return;
+        }
+
+        if (snapshot_node_name &&
+            bdrv_lookup_bs(snapshot_node_name, snapshot_node_name, NULL)) {
+            error_setg(errp, "New snapshot node name already in use");
             return;
         }
-    }
 
-    if (has_snapshot_node_name) {
+        flags = state->old_bs->open_flags;
+        flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING | BDRV_O_COPY_ON_READ);
+
+        /* create new image w/backing file */
+        mode = s->has_mode ? s->mode : NEW_IMAGE_MODE_ABSOLUTE_PATHS;
+        if (mode != NEW_IMAGE_MODE_EXISTING) {
+            int64_t size = bdrv_getlength(state->old_bs);
+            if (size < 0) {
+                error_setg_errno(errp, -size, "bdrv_getlength failed");
+                return;
+            }
+            bdrv_img_create(new_image_file, format,
+                            state->old_bs->filename,
+                            state->old_bs->drv->format_name,
+                            NULL, size, flags, &local_err, false);
+            if (local_err) {
+                error_propagate(errp, local_err);
+                return;
+            }
+        }
+
         options = qdict_new();
-        qdict_put(options, "node-name",
-                  qstring_from_str(snapshot_node_name));
+        if (s->has_snapshot_node_name) {
+            qdict_put(options, "node-name",
+                      qstring_from_str(snapshot_node_name));
+        }
+        qdict_put(options, "driver", qstring_from_str(format));
+
+        flags |= BDRV_O_NO_BACKING;
     }
 
-    /* TODO Inherit bs->options or only take explicit options with an
-     * extended QMP command? */
     assert(state->new_bs == NULL);
-    ret = bdrv_open(&state->new_bs, new_image_file, NULL, options,
-                    flags | BDRV_O_NO_BACKING, drv, &local_err);
+    ret = bdrv_open(&state->new_bs, new_image_file, snapshot_ref, options,
+                    flags, errp);
     /* We will manually add the backing_hd field to the bs later */
     if (ret != 0) {
-        error_propagate(errp, local_err);
+        return;
+    }
+
+    if (state->new_bs->blk != NULL) {
+        error_setg(errp, "The snapshot is already in use by %s",
+                   blk_name(state->new_bs->blk));
+        return;
+    }
+
+    if (bdrv_op_is_blocked(state->new_bs, BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
+                           errp)) {
+        return;
+    }
+
+    if (state->new_bs->backing != NULL) {
+        error_setg(errp, "The snapshot already has a backing image");
+        return;
+    }
+
+    if (!state->new_bs->drv->supports_backing) {
+        error_setg(errp, "The snapshot does not support backing images");
     }
 }
 
-static void external_snapshot_commit(BlkTransactionState *common)
+static void external_snapshot_commit(BlkActionState *common)
 {
     ExternalSnapshotState *state =
                              DO_UPCAST(ExternalSnapshotState, common, common);
@@ -1546,41 +1818,59 @@ static void external_snapshot_commit(BlkTransactionState *common)
     /* We don't need (or want) to use the transactional
      * bdrv_reopen_multiple() across all the entries at once, because we
      * don't want to abort all of them if one of them fails the reopen */
-    bdrv_reopen(state->new_bs, state->new_bs->open_flags & ~BDRV_O_RDWR,
-                NULL);
-
-    aio_context_release(state->aio_context);
+    if (!state->old_bs->copy_on_read) {
+        bdrv_reopen(state->old_bs, state->old_bs->open_flags & ~BDRV_O_RDWR,
+                    NULL);
+    }
 }
 
-static void external_snapshot_abort(BlkTransactionState *common)
+static void external_snapshot_abort(BlkActionState *common)
 {
     ExternalSnapshotState *state =
                              DO_UPCAST(ExternalSnapshotState, common, common);
     if (state->new_bs) {
         bdrv_unref(state->new_bs);
     }
+}
+
+static void external_snapshot_clean(BlkActionState *common)
+{
+    ExternalSnapshotState *state =
+                             DO_UPCAST(ExternalSnapshotState, common, common);
     if (state->aio_context) {
+        bdrv_drained_end(state->old_bs);
         aio_context_release(state->aio_context);
     }
 }
 
 typedef struct DriveBackupState {
-    BlkTransactionState common;
+    BlkActionState common;
     BlockDriverState *bs;
     AioContext *aio_context;
     BlockJob *job;
 } DriveBackupState;
 
-static void drive_backup_prepare(BlkTransactionState *common, Error **errp)
+static void do_drive_backup(const char *device, const char *target,
+                            bool has_format, const char *format,
+                            enum MirrorSyncMode sync,
+                            bool has_mode, enum NewImageMode mode,
+                            bool has_speed, int64_t speed,
+                            bool has_bitmap, const char *bitmap,
+                            bool has_on_source_error,
+                            BlockdevOnError on_source_error,
+                            bool has_on_target_error,
+                            BlockdevOnError on_target_error,
+                            BlockJobTxn *txn, Error **errp);
+
+static void drive_backup_prepare(BlkActionState *common, Error **errp)
 {
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
-    BlockDriverState *bs;
     BlockBackend *blk;
     DriveBackup *backup;
     Error *local_err = NULL;
 
-    assert(common->action->kind == TRANSACTION_ACTION_KIND_DRIVE_BACKUP);
-    backup = common->action->drive_backup;
+    assert(common->action->type == TRANSACTION_ACTION_KIND_DRIVE_BACKUP);
+    backup = common->action->u.drive_backup.data;
 
     blk = blk_by_name(backup->device);
     if (!blk) {
@@ -1588,31 +1878,36 @@ static void drive_backup_prepare(BlkTransactionState *common, Error **errp)
                   "Device '%s' not found", backup->device);
         return;
     }
-    bs = blk_bs(blk);
+
+    if (!blk_is_available(blk)) {
+        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, backup->device);
+        return;
+    }
 
     /* AioContext is released in .clean() */
-    state->aio_context = bdrv_get_aio_context(bs);
+    state->aio_context = blk_get_aio_context(blk);
     aio_context_acquire(state->aio_context);
-
-    qmp_drive_backup(backup->device, backup->target,
-                     backup->has_format, backup->format,
-                     backup->sync,
-                     backup->has_mode, backup->mode,
-                     backup->has_speed, backup->speed,
-                     backup->has_bitmap, backup->bitmap,
-                     backup->has_on_source_error, backup->on_source_error,
-                     backup->has_on_target_error, backup->on_target_error,
-                     &local_err);
+    bdrv_drained_begin(blk_bs(blk));
+    state->bs = blk_bs(blk);
+
+    do_drive_backup(backup->device, backup->target,
+                    backup->has_format, backup->format,
+                    backup->sync,
+                    backup->has_mode, backup->mode,
+                    backup->has_speed, backup->speed,
+                    backup->has_bitmap, backup->bitmap,
+                    backup->has_on_source_error, backup->on_source_error,
+                    backup->has_on_target_error, backup->on_target_error,
+                    common->block_job_txn, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         return;
     }
 
-    state->bs = bs;
     state->job = state->bs->job;
 }
 
-static void drive_backup_abort(BlkTransactionState *common)
+static void drive_backup_abort(BlkActionState *common)
 {
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
     BlockDriverState *bs = state->bs;
@@ -1623,72 +1918,85 @@ static void drive_backup_abort(BlkTransactionState *common)
     }
 }
 
-static void drive_backup_clean(BlkTransactionState *common)
+static void drive_backup_clean(BlkActionState *common)
 {
     DriveBackupState *state = DO_UPCAST(DriveBackupState, common, common);
 
     if (state->aio_context) {
+        bdrv_drained_end(state->bs);
         aio_context_release(state->aio_context);
     }
 }
 
 typedef struct BlockdevBackupState {
-    BlkTransactionState common;
+    BlkActionState common;
     BlockDriverState *bs;
     BlockJob *job;
     AioContext *aio_context;
 } BlockdevBackupState;
 
-static void blockdev_backup_prepare(BlkTransactionState *common, Error **errp)
+static void do_blockdev_backup(const char *device, const char *target,
+                               enum MirrorSyncMode sync,
+                               bool has_speed, int64_t speed,
+                               bool has_on_source_error,
+                               BlockdevOnError on_source_error,
+                               bool has_on_target_error,
+                               BlockdevOnError on_target_error,
+                               BlockJobTxn *txn, Error **errp);
+
+static void blockdev_backup_prepare(BlkActionState *common, Error **errp)
 {
     BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
     BlockdevBackup *backup;
-    BlockDriverState *bs, *target;
-    BlockBackend *blk;
+    BlockBackend *blk, *target;
     Error *local_err = NULL;
 
-    assert(common->action->kind == TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP);
-    backup = common->action->blockdev_backup;
+    assert(common->action->type == TRANSACTION_ACTION_KIND_BLOCKDEV_BACKUP);
+    backup = common->action->u.blockdev_backup.data;
 
     blk = blk_by_name(backup->device);
     if (!blk) {
         error_setg(errp, "Device '%s' not found", backup->device);
         return;
     }
-    bs = blk_bs(blk);
 
-    blk = blk_by_name(backup->target);
-    if (!blk) {
+    if (!blk_is_available(blk)) {
+        error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, backup->device);
+        return;
+    }
+
+    target = blk_by_name(backup->target);
+    if (!target) {
         error_setg(errp, "Device '%s' not found", backup->target);
         return;
     }
-    target = blk_bs(blk);
 
     /* AioContext is released in .clean() */
-    state->aio_context = bdrv_get_aio_context(bs);
-    if (state->aio_context != bdrv_get_aio_context(target)) {
+    state->aio_context = blk_get_aio_context(blk);
+    if (state->aio_context != blk_get_aio_context(target)) {
         state->aio_context = NULL;
         error_setg(errp, "Backup between two IO threads is not implemented");
         return;
     }
     aio_context_acquire(state->aio_context);
-
-    qmp_blockdev_backup(backup->device, backup->target,
-                        backup->sync,
-                        backup->has_speed, backup->speed,
-                        backup->has_on_source_error, backup->on_source_error,
-                        backup->has_on_target_error, backup->on_target_error,
-                        &local_err);
+    state->bs = blk_bs(blk);
+    bdrv_drained_begin(state->bs);
+
+    do_blockdev_backup(backup->device, backup->target,
+                       backup->sync,
+                       backup->has_speed, backup->speed,
+                       backup->has_on_source_error, backup->on_source_error,
+                       backup->has_on_target_error, backup->on_target_error,
+                       common->block_job_txn, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         return;
     }
 
-    state->bs = bs;
     state->job = state->bs->job;
 }
 
-static void blockdev_backup_abort(BlkTransactionState *common)
+static void blockdev_backup_abort(BlkActionState *common)
 {
     BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
     BlockDriverState *bs = state->bs;
@@ -1699,31 +2007,148 @@ static void blockdev_backup_abort(BlkTransactionState *common)
     }
 }
 
-static void blockdev_backup_clean(BlkTransactionState *common)
+static void blockdev_backup_clean(BlkActionState *common)
 {
     BlockdevBackupState *state = DO_UPCAST(BlockdevBackupState, common, common);
 
+    if (state->aio_context) {
+        bdrv_drained_end(state->bs);
+        aio_context_release(state->aio_context);
+    }
+}
+
+typedef struct BlockDirtyBitmapState {
+    BlkActionState common;
+    BdrvDirtyBitmap *bitmap;
+    BlockDriverState *bs;
+    AioContext *aio_context;
+    HBitmap *backup;
+    bool prepared;
+} BlockDirtyBitmapState;
+
+static void block_dirty_bitmap_add_prepare(BlkActionState *common,
+                                           Error **errp)
+{
+    Error *local_err = NULL;
+    BlockDirtyBitmapAdd *action;
+    BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
+                                             common, common);
+
+    if (action_check_completion_mode(common, errp) < 0) {
+        return;
+    }
+
+    action = common->action->u.block_dirty_bitmap_add.data;
+    /* AIO context taken and released within qmp_block_dirty_bitmap_add */
+    qmp_block_dirty_bitmap_add(action->node, action->name,
+                               action->has_granularity, action->granularity,
+                               &local_err);
+
+    if (!local_err) {
+        state->prepared = true;
+    } else {
+        error_propagate(errp, local_err);
+    }
+}
+
+static void block_dirty_bitmap_add_abort(BlkActionState *common)
+{
+    BlockDirtyBitmapAdd *action;
+    BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
+                                             common, common);
+
+    action = common->action->u.block_dirty_bitmap_add.data;
+    /* Should not be able to fail: IF the bitmap was added via .prepare(),
+     * then the node reference and bitmap name must have been valid.
+     */
+    if (state->prepared) {
+        qmp_block_dirty_bitmap_remove(action->node, action->name, &error_abort);
+    }
+}
+
+static void block_dirty_bitmap_clear_prepare(BlkActionState *common,
+                                             Error **errp)
+{
+    BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
+                                             common, common);
+    BlockDirtyBitmap *action;
+
+    if (action_check_completion_mode(common, errp) < 0) {
+        return;
+    }
+
+    action = common->action->u.block_dirty_bitmap_clear.data;
+    state->bitmap = block_dirty_bitmap_lookup(action->node,
+                                              action->name,
+                                              &state->bs,
+                                              &state->aio_context,
+                                              errp);
+    if (!state->bitmap) {
+        return;
+    }
+
+    if (bdrv_dirty_bitmap_frozen(state->bitmap)) {
+        error_setg(errp, "Cannot modify a frozen bitmap");
+        return;
+    } else if (!bdrv_dirty_bitmap_enabled(state->bitmap)) {
+        error_setg(errp, "Cannot clear a disabled bitmap");
+        return;
+    }
+
+    bdrv_clear_dirty_bitmap(state->bitmap, &state->backup);
+    /* AioContext is released in .clean() */
+}
+
+static void block_dirty_bitmap_clear_abort(BlkActionState *common)
+{
+    BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
+                                             common, common);
+
+    bdrv_undo_clear_dirty_bitmap(state->bitmap, state->backup);
+}
+
+static void block_dirty_bitmap_clear_commit(BlkActionState *common)
+{
+    BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
+                                             common, common);
+
+    hbitmap_free(state->backup);
+}
+
+static void block_dirty_bitmap_clear_clean(BlkActionState *common)
+{
+    BlockDirtyBitmapState *state = DO_UPCAST(BlockDirtyBitmapState,
+                                             common, common);
+
     if (state->aio_context) {
         aio_context_release(state->aio_context);
     }
 }
 
-static void abort_prepare(BlkTransactionState *common, Error **errp)
+static void abort_prepare(BlkActionState *common, Error **errp)
 {
     error_setg(errp, "Transaction aborted using Abort action");
 }
 
-static void abort_commit(BlkTransactionState *common)
+static void abort_commit(BlkActionState *common)
 {
     g_assert_not_reached(); /* this action never succeeds */
 }
 
-static const BdrvActionOps actions[] = {
+static const BlkActionOps actions[] = {
+    [TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT] = {
+        .instance_size = sizeof(ExternalSnapshotState),
+        .prepare  = external_snapshot_prepare,
+        .commit   = external_snapshot_commit,
+        .abort = external_snapshot_abort,
+        .clean = external_snapshot_clean,
+    },
     [TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC] = {
         .instance_size = sizeof(ExternalSnapshotState),
         .prepare  = external_snapshot_prepare,
         .commit   = external_snapshot_commit,
         .abort = external_snapshot_abort,
+        .clean = external_snapshot_clean,
     },
     [TRANSACTION_ACTION_KIND_DRIVE_BACKUP] = {
         .instance_size = sizeof(DriveBackupState),
@@ -1738,7 +2163,7 @@ static const BdrvActionOps actions[] = {
         .clean = blockdev_backup_clean,
     },
     [TRANSACTION_ACTION_KIND_ABORT] = {
-        .instance_size = sizeof(BlkTransactionState),
+        .instance_size = sizeof(BlkActionState),
         .prepare = abort_prepare,
         .commit = abort_commit,
     },
@@ -1748,40 +2173,85 @@ static const BdrvActionOps actions[] = {
         .abort = internal_snapshot_abort,
         .clean = internal_snapshot_clean,
     },
+    [TRANSACTION_ACTION_KIND_BLOCK_DIRTY_BITMAP_ADD] = {
+        .instance_size = sizeof(BlockDirtyBitmapState),
+        .prepare = block_dirty_bitmap_add_prepare,
+        .abort = block_dirty_bitmap_add_abort,
+    },
+    [TRANSACTION_ACTION_KIND_BLOCK_DIRTY_BITMAP_CLEAR] = {
+        .instance_size = sizeof(BlockDirtyBitmapState),
+        .prepare = block_dirty_bitmap_clear_prepare,
+        .commit = block_dirty_bitmap_clear_commit,
+        .abort = block_dirty_bitmap_clear_abort,
+        .clean = block_dirty_bitmap_clear_clean,
+    }
 };
 
+/**
+ * Allocate a TransactionProperties structure if necessary, and fill
+ * that structure with desired defaults if they are unset.
+ */
+static TransactionProperties *get_transaction_properties(
+    TransactionProperties *props)
+{
+    if (!props) {
+        props = g_new0(TransactionProperties, 1);
+    }
+
+    if (!props->has_completion_mode) {
+        props->has_completion_mode = true;
+        props->completion_mode = ACTION_COMPLETION_MODE_INDIVIDUAL;
+    }
+
+    return props;
+}
+
 /*
  * 'Atomic' group operations.  The operations are performed as a set, and if
  * any fail then we roll back all operations in the group.
  */
-void qmp_transaction(TransactionActionList *dev_list, Error **errp)
+void qmp_transaction(TransactionActionList *dev_list,
+                     bool has_props,
+                     struct TransactionProperties *props,
+                     Error **errp)
 {
     TransactionActionList *dev_entry = dev_list;
-    BlkTransactionState *state, *next;
+    BlockJobTxn *block_job_txn = NULL;
+    BlkActionState *state, *next;
     Error *local_err = NULL;
 
-    QSIMPLEQ_HEAD(snap_bdrv_states, BlkTransactionState) snap_bdrv_states;
+    QSIMPLEQ_HEAD(snap_bdrv_states, BlkActionState) snap_bdrv_states;
     QSIMPLEQ_INIT(&snap_bdrv_states);
 
+    /* Does this transaction get canceled as a group on failure?
+     * If not, we don't really need to make a BlockJobTxn.
+     */
+    props = get_transaction_properties(props);
+    if (props->completion_mode != ACTION_COMPLETION_MODE_INDIVIDUAL) {
+        block_job_txn = block_job_txn_new();
+    }
+
     /* drain all i/o before any operations */
     bdrv_drain_all();
 
     /* We don't do anything in this loop that commits us to the operations */
     while (NULL != dev_entry) {
         TransactionAction *dev_info = NULL;
-        const BdrvActionOps *ops;
+        const BlkActionOps *ops;
 
         dev_info = dev_entry->value;
         dev_entry = dev_entry->next;
 
-        assert(dev_info->kind < ARRAY_SIZE(actions));
+        assert(dev_info->type < ARRAY_SIZE(actions));
 
-        ops = &actions[dev_info->kind];
+        ops = &actions[dev_info->type];
         assert(ops->instance_size > 0);
 
         state = g_malloc0(ops->instance_size);
         state->ops = ops;
         state->action = dev_info;
+        state->block_job_txn = block_job_txn;
+        state->txn_props = props;
         QSIMPLEQ_INSERT_TAIL(&snap_bdrv_states, state, entry);
 
         state->ops->prepare(state, &local_err);
@@ -1814,42 +2284,91 @@ exit:
         }
         g_free(state);
     }
+    if (!has_props) {
+        qapi_free_TransactionProperties(props);
+    }
+    block_job_txn_unref(block_job_txn);
 }
 
+void qmp_eject(const char *device, bool has_force, bool force, Error **errp)
+{
+    Error *local_err = NULL;
+
+    qmp_blockdev_open_tray(device, has_force, force, &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
+    qmp_x_blockdev_remove_medium(device, errp);
+}
 
-static void eject_device(BlockBackend *blk, int force, Error **errp)
+void qmp_block_passwd(bool has_device, const char *device,
+                      bool has_node_name, const char *node_name,
+                      const char *password, Error **errp)
 {
-    BlockDriverState *bs = blk_bs(blk);
+    Error *local_err = NULL;
+    BlockDriverState *bs;
     AioContext *aio_context;
 
+    bs = bdrv_lookup_bs(has_device ? device : NULL,
+                        has_node_name ? node_name : NULL,
+                        &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
+        return;
+    }
+
     aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
-    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_EJECT, errp)) {
-        goto out;
+    bdrv_add_key(bs, password, errp);
+
+    aio_context_release(aio_context);
+}
+
+void qmp_blockdev_open_tray(const char *device, bool has_force, bool force,
+                            Error **errp)
+{
+    BlockBackend *blk;
+    bool locked;
+
+    if (!has_force) {
+        force = false;
     }
+
+    blk = blk_by_name(device);
+    if (!blk) {
+        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
+                  "Device '%s' not found", device);
+        return;
+    }
+
     if (!blk_dev_has_removable_media(blk)) {
-        error_setg(errp, "Device '%s' is not removable",
-                   bdrv_get_device_name(bs));
-        goto out;
+        error_setg(errp, "Device '%s' is not removable", device);
+        return;
     }
 
-    if (blk_dev_is_medium_locked(blk) && !blk_dev_is_tray_open(blk)) {
-        blk_dev_eject_request(blk, force);
-        if (!force) {
-            error_setg(errp, "Device '%s' is locked",
-                       bdrv_get_device_name(bs));
-            goto out;
-        }
+    if (!blk_dev_has_tray(blk)) {
+        /* Ignore this command on tray-less devices */
+        return;
     }
 
-    bdrv_close(bs);
+    if (blk_dev_is_tray_open(blk)) {
+        return;
+    }
 
-out:
-    aio_context_release(aio_context);
+    locked = blk_dev_is_medium_locked(blk);
+    if (locked) {
+        blk_dev_eject_request(blk, force);
+    }
+
+    if (!locked || force) {
+        blk_dev_change_media_cb(blk, false);
+    }
 }
 
-void qmp_eject(const char *device, bool has_force, bool force, Error **errp)
+void qmp_blockdev_close_tray(const char *device, Error **errp)
 {
     BlockBackend *blk;
 
@@ -1860,92 +2379,230 @@ void qmp_eject(const char *device, bool has_force, bool force, Error **errp)
         return;
     }
 
-    eject_device(blk, force, errp);
+    if (!blk_dev_has_removable_media(blk)) {
+        error_setg(errp, "Device '%s' is not removable", device);
+        return;
+    }
+
+    if (!blk_dev_has_tray(blk)) {
+        /* Ignore this command on tray-less devices */
+        return;
+    }
+
+    if (!blk_dev_is_tray_open(blk)) {
+        return;
+    }
+
+    blk_dev_change_media_cb(blk, true);
 }
 
-void qmp_block_passwd(bool has_device, const char *device,
-                      bool has_node_name, const char *node_name,
-                      const char *password, Error **errp)
+void qmp_x_blockdev_remove_medium(const char *device, Error **errp)
 {
-    Error *local_err = NULL;
+    BlockBackend *blk;
     BlockDriverState *bs;
     AioContext *aio_context;
+    bool has_device;
 
-    bs = bdrv_lookup_bs(has_device ? device : NULL,
-                        has_node_name ? node_name : NULL,
-                        &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
+    blk = blk_by_name(device);
+    if (!blk) {
+        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
+                  "Device '%s' not found", device);
+        return;
+    }
+
+    /* For BBs without a device, we can exchange the BDS tree at will */
+    has_device = blk_get_attached_dev(blk);
+
+    if (has_device && !blk_dev_has_removable_media(blk)) {
+        error_setg(errp, "Device '%s' is not removable", device);
+        return;
+    }
+
+    if (has_device && blk_dev_has_tray(blk) && !blk_dev_is_tray_open(blk)) {
+        error_setg(errp, "Tray of device '%s' is not open", device);
+        return;
+    }
+
+    bs = blk_bs(blk);
+    if (!bs) {
         return;
     }
 
     aio_context = bdrv_get_aio_context(bs);
     aio_context_acquire(aio_context);
 
-    bdrv_add_key(bs, password, errp);
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_EJECT, errp)) {
+        goto out;
+    }
 
+    blk_remove_bs(blk);
+
+    if (!blk_dev_has_tray(blk)) {
+        /* For tray-less devices, blockdev-open-tray is a no-op (or may not be
+         * called at all); therefore, the medium needs to be ejected here.
+         * Do it after blk_remove_bs() so blk_is_inserted(blk) returns the @load
+         * value passed here (i.e. false). */
+        blk_dev_change_media_cb(blk, false);
+    }
+
+out:
     aio_context_release(aio_context);
 }
 
-/* Assumes AioContext is held */
-static void qmp_bdrv_open_encrypted(BlockDriverState *bs, const char *filename,
-                                    int bdrv_flags, BlockDriver *drv,
-                                    const char *password, Error **errp)
+static void qmp_blockdev_insert_anon_medium(const char *device,
+                                            BlockDriverState *bs, Error **errp)
 {
-    Error *local_err = NULL;
-    int ret;
+    BlockBackend *blk;
+    bool has_device;
 
-    ret = bdrv_open(&bs, filename, NULL, NULL, bdrv_flags, drv, &local_err);
-    if (ret < 0) {
-        error_propagate(errp, local_err);
+    blk = blk_by_name(device);
+    if (!blk) {
+        error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
+                  "Device '%s' not found", device);
         return;
     }
 
-    bdrv_add_key(bs, password, errp);
+    /* For BBs without a device, we can exchange the BDS tree at will */
+    has_device = blk_get_attached_dev(blk);
+
+    if (has_device && !blk_dev_has_removable_media(blk)) {
+        error_setg(errp, "Device '%s' is not removable", device);
+        return;
+    }
+
+    if (has_device && blk_dev_has_tray(blk) && !blk_dev_is_tray_open(blk)) {
+        error_setg(errp, "Tray of device '%s' is not open", device);
+        return;
+    }
+
+    if (blk_bs(blk)) {
+        error_setg(errp, "There already is a medium in device '%s'", device);
+        return;
+    }
+
+    blk_insert_bs(blk, bs);
+
+    if (!blk_dev_has_tray(blk)) {
+        /* For tray-less devices, blockdev-close-tray is a no-op (or may not be
+         * called at all); therefore, the medium needs to be pushed into the
+         * slot here.
+         * Do it after blk_insert_bs() so blk_is_inserted(blk) returns the @load
+         * value passed here (i.e. true). */
+        blk_dev_change_media_cb(blk, true);
+    }
 }
 
-void qmp_change_blockdev(const char *device, const char *filename,
-                         const char *format, Error **errp)
+void qmp_x_blockdev_insert_medium(const char *device, const char *node_name,
+                                  Error **errp)
 {
-    BlockBackend *blk;
     BlockDriverState *bs;
-    AioContext *aio_context;
-    BlockDriver *drv = NULL;
-    int bdrv_flags;
+
+    bs = bdrv_find_node(node_name);
+    if (!bs) {
+        error_setg(errp, "Node '%s' not found", node_name);
+        return;
+    }
+
+    if (bs->blk) {
+        error_setg(errp, "Node '%s' is already in use by '%s'", node_name,
+                   blk_name(bs->blk));
+        return;
+    }
+
+    qmp_blockdev_insert_anon_medium(device, bs, errp);
+}
+
+void qmp_blockdev_change_medium(const char *device, const char *filename,
+                                bool has_format, const char *format,
+                                bool has_read_only,
+                                BlockdevChangeReadOnlyMode read_only,
+                                Error **errp)
+{
+    BlockBackend *blk;
+    BlockDriverState *medium_bs = NULL;
+    int bdrv_flags, ret;
+    QDict *options = NULL;
     Error *err = NULL;
 
     blk = blk_by_name(device);
     if (!blk) {
         error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
                   "Device '%s' not found", device);
-        return;
+        goto fail;
     }
-    bs = blk_bs(blk);
 
-    aio_context = bdrv_get_aio_context(bs);
-    aio_context_acquire(aio_context);
+    if (blk_bs(blk)) {
+        blk_update_root_state(blk);
+    }
 
-    if (format) {
-        drv = bdrv_find_whitelisted_format(format, bs->read_only);
-        if (!drv) {
-            error_setg(errp, QERR_INVALID_BLOCK_FORMAT, format);
-            goto out;
-        }
+    bdrv_flags = blk_get_open_flags_from_root_state(blk);
+    bdrv_flags &= ~(BDRV_O_TEMPORARY | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING |
+        BDRV_O_PROTOCOL);
+
+    if (!has_read_only) {
+        read_only = BLOCKDEV_CHANGE_READ_ONLY_MODE_RETAIN;
+    }
+
+    switch (read_only) {
+    case BLOCKDEV_CHANGE_READ_ONLY_MODE_RETAIN:
+        break;
+
+    case BLOCKDEV_CHANGE_READ_ONLY_MODE_READ_ONLY:
+        bdrv_flags &= ~BDRV_O_RDWR;
+        break;
+
+    case BLOCKDEV_CHANGE_READ_ONLY_MODE_READ_WRITE:
+        bdrv_flags |= BDRV_O_RDWR;
+        break;
+
+    default:
+        abort();
+    }
+
+    if (has_format) {
+        options = qdict_new();
+        qdict_put(options, "driver", qstring_from_str(format));
     }
 
-    eject_device(blk, 0, &err);
+    assert(!medium_bs);
+    ret = bdrv_open(&medium_bs, filename, NULL, options, bdrv_flags, errp);
+    if (ret < 0) {
+        goto fail;
+    }
+
+    blk_apply_root_state(blk, medium_bs);
+
+    bdrv_add_key(medium_bs, NULL, &err);
     if (err) {
         error_propagate(errp, err);
-        goto out;
+        goto fail;
+    }
+
+    qmp_blockdev_open_tray(device, false, false, &err);
+    if (err) {
+        error_propagate(errp, err);
+        goto fail;
     }
 
-    bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
-    bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;
+    qmp_x_blockdev_remove_medium(device, &err);
+    if (err) {
+        error_propagate(errp, err);
+        goto fail;
+    }
+
+    qmp_blockdev_insert_anon_medium(device, medium_bs, &err);
+    if (err) {
+        error_propagate(errp, err);
+        goto fail;
+    }
 
-    qmp_bdrv_open_encrypted(bs, filename, bdrv_flags, drv, NULL, errp);
+    qmp_blockdev_close_tray(device, errp);
 
-out:
-    aio_context_release(aio_context);
+fail:
+    /* If the medium has been inserted, the device has its own reference, so
+     * ours must be relinquished; and if it has not been inserted successfully,
+     * the reference must be relinquished anyway */
+    bdrv_unref(medium_bs);
 }
 
 /* throttling disk I/O limits */
@@ -1966,6 +2623,18 @@ void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
                                int64_t iops_rd_max,
                                bool has_iops_wr_max,
                                int64_t iops_wr_max,
+                               bool has_bps_max_length,
+                               int64_t bps_max_length,
+                               bool has_bps_rd_max_length,
+                               int64_t bps_rd_max_length,
+                               bool has_bps_wr_max_length,
+                               int64_t bps_wr_max_length,
+                               bool has_iops_max_length,
+                               int64_t iops_max_length,
+                               bool has_iops_rd_max_length,
+                               int64_t iops_rd_max_length,
+                               bool has_iops_wr_max_length,
+                               int64_t iops_wr_max_length,
                                bool has_iops_size,
                                int64_t iops_size,
                                bool has_group,
@@ -1982,9 +2651,24 @@ void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
                   "Device '%s' not found", device);
         return;
     }
+
+    aio_context = blk_get_aio_context(blk);
+    aio_context_acquire(aio_context);
+
     bs = blk_bs(blk);
+    if (!bs) {
+        error_setg(errp, "Device '%s' has no medium", device);
+        goto out;
+    }
 
-    memset(&cfg, 0, sizeof(cfg));
+    /* The BlockBackend must be the only parent */
+    assert(QLIST_FIRST(&bs->parents));
+    if (QLIST_NEXT(QLIST_FIRST(&bs->parents), next_parent)) {
+        error_setg(errp, "Cannot throttle device with multiple parents");
+        goto out;
+    }
+
+    throttle_config_init(&cfg);
     cfg.buckets[THROTTLE_BPS_TOTAL].avg = bps;
     cfg.buckets[THROTTLE_BPS_READ].avg  = bps_rd;
     cfg.buckets[THROTTLE_BPS_WRITE].avg = bps_wr;
@@ -2012,32 +2696,49 @@ void qmp_block_set_io_throttle(const char *device, int64_t bps, int64_t bps_rd,
         cfg.buckets[THROTTLE_OPS_WRITE].max = iops_wr_max;
     }
 
+    if (has_bps_max_length) {
+        cfg.buckets[THROTTLE_BPS_TOTAL].burst_length = bps_max_length;
+    }
+    if (has_bps_rd_max_length) {
+        cfg.buckets[THROTTLE_BPS_READ].burst_length = bps_rd_max_length;
+    }
+    if (has_bps_wr_max_length) {
+        cfg.buckets[THROTTLE_BPS_WRITE].burst_length = bps_wr_max_length;
+    }
+    if (has_iops_max_length) {
+        cfg.buckets[THROTTLE_OPS_TOTAL].burst_length = iops_max_length;
+    }
+    if (has_iops_rd_max_length) {
+        cfg.buckets[THROTTLE_OPS_READ].burst_length = iops_rd_max_length;
+    }
+    if (has_iops_wr_max_length) {
+        cfg.buckets[THROTTLE_OPS_WRITE].burst_length = iops_wr_max_length;
+    }
+
     if (has_iops_size) {
         cfg.op_size = iops_size;
     }
 
-    if (!check_throttle_config(&cfg, errp)) {
-        return;
+    if (!throttle_is_valid(&cfg, errp)) {
+        goto out;
     }
 
-    aio_context = bdrv_get_aio_context(bs);
-    aio_context_acquire(aio_context);
-
     if (throttle_enabled(&cfg)) {
         /* Enable I/O limits if they're not enabled yet, otherwise
          * just update the throttling group. */
-        if (!bs->io_limits_enabled) {
+        if (!bs->throttle_state) {
             bdrv_io_limits_enable(bs, has_group ? group : device);
         } else if (has_group) {
             bdrv_io_limits_update_group(bs, group);
         }
         /* Set the new throttling configuration */
         bdrv_set_io_limits(bs, &cfg);
-    } else if (bs->io_limits_enabled) {
+    } else if (bs->throttle_state) {
         /* If all throttling settings are set to 0, disable I/O limits */
         bdrv_io_limits_disable(bs);
     }
 
+out:
     aio_context_release(aio_context);
 }
 
@@ -2131,7 +2832,7 @@ void qmp_block_dirty_bitmap_clear(const char *node, const char *name,
         goto out;
     }
 
-    bdrv_clear_dirty_bitmap(bitmap);
+    bdrv_clear_dirty_bitmap(bitmap, NULL);
 
  out:
     aio_context_release(aio_context);
@@ -2145,12 +2846,20 @@ void hmp_drive_del(Monitor *mon, const QDict *qdict)
     AioContext *aio_context;
     Error *local_err = NULL;
 
+    bs = bdrv_find_node(id);
+    if (bs) {
+        qmp_x_blockdev_del(false, NULL, true, id, &local_err);
+        if (local_err) {
+            error_report_err(local_err);
+        }
+        return;
+    }
+
     blk = blk_by_name(id);
     if (!blk) {
         error_report("Device '%s' not found", id);
         return;
     }
-    bs = blk_bs(blk);
 
     if (!blk_legacy_dinfo(blk)) {
         error_report("Deleting device added with blockdev-add"
@@ -2158,27 +2867,30 @@ void hmp_drive_del(Monitor *mon, const QDict *qdict)
         return;
     }
 
-    aio_context = bdrv_get_aio_context(bs);
+    aio_context = blk_get_aio_context(blk);
     aio_context_acquire(aio_context);
 
-    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_DRIVE_DEL, &local_err)) {
-        error_report_err(local_err);
-        aio_context_release(aio_context);
-        return;
+    bs = blk_bs(blk);
+    if (bs) {
+        if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_DRIVE_DEL, &local_err)) {
+            error_report_err(local_err);
+            aio_context_release(aio_context);
+            return;
+        }
+
+        blk_remove_bs(blk);
     }
 
-    bdrv_close(bs);
+    /* Make the BlockBackend and the attached BlockDriverState anonymous */
+    monitor_remove_blk(blk);
 
-    /* if we have a device attached to this BlockDriverState
-     * then we need to make the drive anonymous until the device
-     * can be removed.  If this is a drive with no device backing
-     * then we can just get rid of the block driver state right here.
+    /* If this BlockBackend has a device attached to it, its refcount will be
+     * decremented when the device is removed; otherwise we have to do so here.
      */
     if (blk_get_attached_dev(blk)) {
-        blk_hide_on_behalf_of_hmp_drive_del(blk);
         /* Further I/O must not pause the guest */
-        bdrv_set_on_error(bs, BLOCKDEV_ON_ERROR_REPORT,
-                          BLOCKDEV_ON_ERROR_REPORT);
+        blk_set_on_error(blk, BLOCKDEV_ON_ERROR_REPORT,
+                         BLOCKDEV_ON_ERROR_REPORT);
     } else {
         blk_unref(blk);
     }
@@ -2272,8 +2984,6 @@ static void block_job_cb(void *opaque, int ret)
     } else {
         block_job_event_completed(bs->job, msg);
     }
-
-    bdrv_put_ref_bh_schedule(bs);
 }
 
 void qmp_block_stream(const char *device,
@@ -2300,11 +3010,16 @@ void qmp_block_stream(const char *device,
                   "Device '%s' not found", device);
         return;
     }
-    bs = blk_bs(blk);
 
-    aio_context = bdrv_get_aio_context(bs);
+    aio_context = blk_get_aio_context(blk);
     aio_context_acquire(aio_context);
 
+    if (!blk_is_available(blk)) {
+        error_setg(errp, "Device '%s' has no medium", device);
+        goto out;
+    }
+    bs = blk_bs(blk);
+
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_STREAM, errp)) {
         goto out;
     }
@@ -2375,11 +3090,16 @@ void qmp_block_commit(const char *device,
                   "Device '%s' not found", device);
         return;
     }
-    bs = blk_bs(blk);
 
-    aio_context = bdrv_get_aio_context(bs);
+    aio_context = blk_get_aio_context(blk);
     aio_context_acquire(aio_context);
 
+    if (!blk_is_available(blk)) {
+        error_setg(errp, "Device '%s' has no medium", device);
+        goto out;
+    }
+    bs = blk_bs(blk);
+
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, errp)) {
         goto out;
     }
@@ -2444,15 +3164,17 @@ out:
     aio_context_release(aio_context);
 }
 
-void qmp_drive_backup(const char *device, const char *target,
-                      bool has_format, const char *format,
-                      enum MirrorSyncMode sync,
-                      bool has_mode, enum NewImageMode mode,
-                      bool has_speed, int64_t speed,
-                      bool has_bitmap, const char *bitmap,
-                      bool has_on_source_error, BlockdevOnError on_source_error,
-                      bool has_on_target_error, BlockdevOnError on_target_error,
-                      Error **errp)
+static void do_drive_backup(const char *device, const char *target,
+                            bool has_format, const char *format,
+                            enum MirrorSyncMode sync,
+                            bool has_mode, enum NewImageMode mode,
+                            bool has_speed, int64_t speed,
+                            bool has_bitmap, const char *bitmap,
+                            bool has_on_source_error,
+                            BlockdevOnError on_source_error,
+                            bool has_on_target_error,
+                            BlockdevOnError on_target_error,
+                            BlockJobTxn *txn, Error **errp)
 {
     BlockBackend *blk;
     BlockDriverState *bs;
@@ -2460,7 +3182,7 @@ void qmp_drive_backup(const char *device, const char *target,
     BlockDriverState *source = NULL;
     BdrvDirtyBitmap *bmap = NULL;
     AioContext *aio_context;
-    BlockDriver *drv = NULL;
+    QDict *options = NULL;
     Error *local_err = NULL;
     int flags;
     int64_t size;
@@ -2485,28 +3207,21 @@ void qmp_drive_backup(const char *device, const char *target,
                   "Device '%s' not found", device);
         return;
     }
-    bs = blk_bs(blk);
 
-    aio_context = bdrv_get_aio_context(bs);
+    aio_context = blk_get_aio_context(blk);
     aio_context_acquire(aio_context);
 
     /* Although backup_run has this check too, we need to use bs->drv below, so
      * do an early check redundantly. */
-    if (!bdrv_is_inserted(bs)) {
+    if (!blk_is_available(blk)) {
         error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
         goto out;
     }
+    bs = blk_bs(blk);
 
     if (!has_format) {
         format = mode == NEW_IMAGE_MODE_EXISTING ? NULL : bs->drv->format_name;
     }
-    if (format) {
-        drv = bdrv_find_format(format);
-        if (!drv) {
-            error_setg(errp, QERR_INVALID_BLOCK_FORMAT, format);
-            goto out;
-        }
-    }
 
     /* Early check to avoid creating target */
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
@@ -2518,7 +3233,7 @@ void qmp_drive_backup(const char *device, const char *target,
     /* See if we have a backing HD we can use to create our new image
      * on top of. */
     if (sync == MIRROR_SYNC_MODE_TOP) {
-        source = bs->backing_hd;
+        source = backing_bs(bs);
         if (!source) {
             sync = MIRROR_SYNC_MODE_FULL;
         }
@@ -2534,7 +3249,7 @@ void qmp_drive_backup(const char *device, const char *target,
     }
 
     if (mode != NEW_IMAGE_MODE_EXISTING) {
-        assert(format && drv);
+        assert(format);
         if (source) {
             bdrv_img_create(target, format, source->filename,
                             source->drv->format_name, NULL,
@@ -2550,8 +3265,13 @@ void qmp_drive_backup(const char *device, const char *target,
         goto out;
     }
 
+    if (format) {
+        options = qdict_new();
+        qdict_put(options, "driver", qstring_from_str(format));
+    }
+
     target_bs = NULL;
-    ret = bdrv_open(&target_bs, target, NULL, NULL, flags, drv, &local_err);
+    ret = bdrv_open(&target_bs, target, NULL, options, flags, &local_err);
     if (ret < 0) {
         error_propagate(errp, local_err);
         goto out;
@@ -2563,13 +3283,14 @@ void qmp_drive_backup(const char *device, const char *target,
         bmap = bdrv_find_dirty_bitmap(bs, bitmap);
         if (!bmap) {
             error_setg(errp, "Bitmap '%s' could not be found", bitmap);
+            bdrv_unref(target_bs);
             goto out;
         }
     }
 
     backup_start(bs, target_bs, speed, sync, bmap,
                  on_source_error, on_target_error,
-                 block_job_cb, bs, &local_err);
+                 block_job_cb, bs, txn, &local_err);
     if (local_err != NULL) {
         bdrv_unref(target_bs);
         error_propagate(errp, local_err);
@@ -2580,21 +3301,39 @@ out:
     aio_context_release(aio_context);
 }
 
+void qmp_drive_backup(const char *device, const char *target,
+                      bool has_format, const char *format,
+                      enum MirrorSyncMode sync,
+                      bool has_mode, enum NewImageMode mode,
+                      bool has_speed, int64_t speed,
+                      bool has_bitmap, const char *bitmap,
+                      bool has_on_source_error, BlockdevOnError on_source_error,
+                      bool has_on_target_error, BlockdevOnError on_target_error,
+                      Error **errp)
+{
+    return do_drive_backup(device, target, has_format, format, sync,
+                           has_mode, mode, has_speed, speed,
+                           has_bitmap, bitmap,
+                           has_on_source_error, on_source_error,
+                           has_on_target_error, on_target_error,
+                           NULL, errp);
+}
+
 BlockDeviceInfoList *qmp_query_named_block_nodes(Error **errp)
 {
     return bdrv_named_nodes_list(errp);
 }
 
-void qmp_blockdev_backup(const char *device, const char *target,
+void do_blockdev_backup(const char *device, const char *target,
                          enum MirrorSyncMode sync,
                          bool has_speed, int64_t speed,
                          bool has_on_source_error,
                          BlockdevOnError on_source_error,
                          bool has_on_target_error,
                          BlockdevOnError on_target_error,
-                         Error **errp)
+                         BlockJobTxn *txn, Error **errp)
 {
-    BlockBackend *blk;
+    BlockBackend *blk, *target_blk;
     BlockDriverState *bs;
     BlockDriverState *target_bs;
     Error *local_err = NULL;
@@ -2615,22 +3354,32 @@ void qmp_blockdev_backup(const char *device, const char *target,
         error_setg(errp, "Device '%s' not found", device);
         return;
     }
-    bs = blk_bs(blk);
 
-    aio_context = bdrv_get_aio_context(bs);
+    aio_context = blk_get_aio_context(blk);
     aio_context_acquire(aio_context);
 
-    blk = blk_by_name(target);
-    if (!blk) {
+    if (!blk_is_available(blk)) {
+        error_setg(errp, "Device '%s' has no medium", device);
+        goto out;
+    }
+    bs = blk_bs(blk);
+
+    target_blk = blk_by_name(target);
+    if (!target_blk) {
         error_setg(errp, "Device '%s' not found", target);
         goto out;
     }
-    target_bs = blk_bs(blk);
+
+    if (!blk_is_available(target_blk)) {
+        error_setg(errp, "Device '%s' has no medium", target);
+        goto out;
+    }
+    target_bs = blk_bs(target_blk);
 
     bdrv_ref(target_bs);
     bdrv_set_aio_context(target_bs, aio_context);
     backup_start(bs, target_bs, speed, sync, NULL, on_source_error,
-                 on_target_error, block_job_cb, bs, &local_err);
+                 on_target_error, block_job_cb, bs, txn, &local_err);
     if (local_err != NULL) {
         bdrv_unref(target_bs);
         error_propagate(errp, local_err);
@@ -2639,30 +3388,38 @@ out:
     aio_context_release(aio_context);
 }
 
-void qmp_drive_mirror(const char *device, const char *target,
-                      bool has_format, const char *format,
-                      bool has_node_name, const char *node_name,
-                      bool has_replaces, const char *replaces,
-                      enum MirrorSyncMode sync,
-                      bool has_mode, enum NewImageMode mode,
-                      bool has_speed, int64_t speed,
-                      bool has_granularity, uint32_t granularity,
-                      bool has_buf_size, int64_t buf_size,
-                      bool has_on_source_error, BlockdevOnError on_source_error,
-                      bool has_on_target_error, BlockdevOnError on_target_error,
-                      bool has_unmap, bool unmap,
-                      Error **errp)
+void qmp_blockdev_backup(const char *device, const char *target,
+                         enum MirrorSyncMode sync,
+                         bool has_speed, int64_t speed,
+                         bool has_on_source_error,
+                         BlockdevOnError on_source_error,
+                         bool has_on_target_error,
+                         BlockdevOnError on_target_error,
+                         Error **errp)
+{
+    do_blockdev_backup(device, target, sync, has_speed, speed,
+                       has_on_source_error, on_source_error,
+                       has_on_target_error, on_target_error,
+                       NULL, errp);
+}
+
+/* Parameter check and block job starting for drive mirroring.
+ * Caller should hold @device and @target's aio context (must be the same).
+ **/
+static void blockdev_mirror_common(BlockDriverState *bs,
+                                   BlockDriverState *target,
+                                   bool has_replaces, const char *replaces,
+                                   enum MirrorSyncMode sync,
+                                   bool has_speed, int64_t speed,
+                                   bool has_granularity, uint32_t granularity,
+                                   bool has_buf_size, int64_t buf_size,
+                                   bool has_on_source_error,
+                                   BlockdevOnError on_source_error,
+                                   bool has_on_target_error,
+                                   BlockdevOnError on_target_error,
+                                   bool has_unmap, bool unmap,
+                                   Error **errp)
 {
-    BlockBackend *blk;
-    BlockDriverState *bs;
-    BlockDriverState *source, *target_bs;
-    AioContext *aio_context;
-    BlockDriver *drv = NULL;
-    Error *local_err = NULL;
-    QDict *options = NULL;
-    int flags;
-    int64_t size;
-    int ret;
 
     if (!has_speed) {
         speed = 0;
@@ -2673,9 +3430,6 @@ void qmp_drive_mirror(const char *device, const char *target,
     if (!has_on_target_error) {
         on_target_error = BLOCKDEV_ON_ERROR_REPORT;
     }
-    if (!has_mode) {
-        mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
-    }
     if (!has_granularity) {
         granularity = 0;
     }
@@ -2697,39 +3451,80 @@ void qmp_drive_mirror(const char *device, const char *target,
         return;
     }
 
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_MIRROR_SOURCE, errp)) {
+        return;
+    }
+    if (bdrv_op_is_blocked(target, BLOCK_OP_TYPE_MIRROR_TARGET, errp)) {
+        return;
+    }
+    if (target->blk) {
+        error_setg(errp, "Cannot mirror to an attached block device");
+        return;
+    }
+
+    if (!bs->backing && sync == MIRROR_SYNC_MODE_TOP) {
+        sync = MIRROR_SYNC_MODE_FULL;
+    }
+
+    /* pass the node name to replace to mirror start since it's loose coupling
+     * and will allow to check whether the node still exist at mirror completion
+     */
+    mirror_start(bs, target,
+                 has_replaces ? replaces : NULL,
+                 speed, granularity, buf_size, sync,
+                 on_source_error, on_target_error, unmap,
+                 block_job_cb, bs, errp);
+}
+
+void qmp_drive_mirror(const char *device, const char *target,
+                      bool has_format, const char *format,
+                      bool has_node_name, const char *node_name,
+                      bool has_replaces, const char *replaces,
+                      enum MirrorSyncMode sync,
+                      bool has_mode, enum NewImageMode mode,
+                      bool has_speed, int64_t speed,
+                      bool has_granularity, uint32_t granularity,
+                      bool has_buf_size, int64_t buf_size,
+                      bool has_on_source_error, BlockdevOnError on_source_error,
+                      bool has_on_target_error, BlockdevOnError on_target_error,
+                      bool has_unmap, bool unmap,
+                      Error **errp)
+{
+    BlockDriverState *bs;
+    BlockBackend *blk;
+    BlockDriverState *source, *target_bs;
+    AioContext *aio_context;
+    Error *local_err = NULL;
+    QDict *options = NULL;
+    int flags;
+    int64_t size;
+    int ret;
+
     blk = blk_by_name(device);
     if (!blk) {
         error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
                   "Device '%s' not found", device);
         return;
     }
-    bs = blk_bs(blk);
 
-    aio_context = bdrv_get_aio_context(bs);
+    aio_context = blk_get_aio_context(blk);
     aio_context_acquire(aio_context);
 
-    if (!bdrv_is_inserted(bs)) {
+    if (!blk_is_available(blk)) {
         error_setg(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
         goto out;
     }
+    bs = blk_bs(blk);
+    if (!has_mode) {
+        mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
+    }
 
     if (!has_format) {
         format = mode == NEW_IMAGE_MODE_EXISTING ? NULL : bs->drv->format_name;
     }
-    if (format) {
-        drv = bdrv_find_format(format);
-        if (!drv) {
-            error_setg(errp, QERR_INVALID_BLOCK_FORMAT, format);
-            goto out;
-        }
-    }
-
-    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_MIRROR, errp)) {
-        goto out;
-    }
 
     flags = bs->open_flags | BDRV_O_RDWR;
-    source = bs->backing_hd;
+    source = backing_bs(bs);
     if (!source && sync == MIRROR_SYNC_MODE_TOP) {
         sync = MIRROR_SYNC_MODE_FULL;
     }
@@ -2754,7 +3549,7 @@ void qmp_drive_mirror(const char *device, const char *target,
             goto out;
         }
 
-        to_replace_bs = check_to_replace_node(replaces, &local_err);
+        to_replace_bs = check_to_replace_node(bs, replaces, &local_err);
 
         if (!to_replace_bs) {
             error_propagate(errp, local_err);
@@ -2777,7 +3572,7 @@ void qmp_drive_mirror(const char *device, const char *target,
         && mode != NEW_IMAGE_MODE_EXISTING)
     {
         /* create new image w/o backing file */
-        assert(format && drv);
+        assert(format);
         bdrv_img_create(target, format,
                         NULL, NULL, NULL, size, flags, &local_err, false);
     } else {
@@ -2801,17 +3596,20 @@ void qmp_drive_mirror(const char *device, const char *target,
         goto out;
     }
 
+    options = qdict_new();
     if (has_node_name) {
-        options = qdict_new();
         qdict_put(options, "node-name", qstring_from_str(node_name));
     }
+    if (format) {
+        qdict_put(options, "driver", qstring_from_str(format));
+    }
 
     /* Mirroring takes care of copy-on-write using the source's backing
      * file.
      */
     target_bs = NULL;
     ret = bdrv_open(&target_bs, target, NULL, options,
-                    flags | BDRV_O_NO_BACKING, drv, &local_err);
+                    flags | BDRV_O_NO_BACKING, &local_err);
     if (ret < 0) {
         error_propagate(errp, local_err);
         goto out;
@@ -2819,22 +3617,78 @@ void qmp_drive_mirror(const char *device, const char *target,
 
     bdrv_set_aio_context(target_bs, aio_context);
 
-    /* pass the node name to replace to mirror start since it's loose coupling
-     * and will allow to check whether the node still exist at mirror completion
-     */
-    mirror_start(bs, target_bs,
-                 has_replaces ? replaces : NULL,
-                 speed, granularity, buf_size, sync,
-                 on_source_error, on_target_error,
-                 unmap,
-                 block_job_cb, bs, &local_err);
-    if (local_err != NULL) {
+    blockdev_mirror_common(bs, target_bs,
+                           has_replaces, replaces, sync,
+                           has_speed, speed,
+                           has_granularity, granularity,
+                           has_buf_size, buf_size,
+                           has_on_source_error, on_source_error,
+                           has_on_target_error, on_target_error,
+                           has_unmap, unmap,
+                           &local_err);
+    if (local_err) {
+        error_propagate(errp, local_err);
         bdrv_unref(target_bs);
+    }
+out:
+    aio_context_release(aio_context);
+}
+
+void qmp_blockdev_mirror(const char *device, const char *target,
+                         bool has_replaces, const char *replaces,
+                         MirrorSyncMode sync,
+                         bool has_speed, int64_t speed,
+                         bool has_granularity, uint32_t granularity,
+                         bool has_buf_size, int64_t buf_size,
+                         bool has_on_source_error,
+                         BlockdevOnError on_source_error,
+                         bool has_on_target_error,
+                         BlockdevOnError on_target_error,
+                         Error **errp)
+{
+    BlockDriverState *bs;
+    BlockBackend *blk;
+    BlockDriverState *target_bs;
+    AioContext *aio_context;
+    Error *local_err = NULL;
+
+    blk = blk_by_name(device);
+    if (!blk) {
+        error_setg(errp, "Device '%s' not found", device);
+        return;
+    }
+    bs = blk_bs(blk);
+
+    if (!bs) {
+        error_setg(errp, "Device '%s' has no media", device);
+        return;
+    }
+
+    target_bs = bdrv_lookup_bs(target, target, errp);
+    if (!target_bs) {
+        return;
+    }
+
+    aio_context = bdrv_get_aio_context(bs);
+    aio_context_acquire(aio_context);
+
+    bdrv_ref(target_bs);
+    bdrv_set_aio_context(target_bs, aio_context);
+
+    blockdev_mirror_common(bs, target_bs,
+                           has_replaces, replaces, sync,
+                           has_speed, speed,
+                           has_granularity, granularity,
+                           has_buf_size, buf_size,
+                           has_on_source_error, on_source_error,
+                           has_on_target_error, on_target_error,
+                           true, true,
+                           &local_err);
+    if (local_err) {
         error_propagate(errp, local_err);
-        goto out;
+        bdrv_unref(target_bs);
     }
 
-out:
     aio_context_release(aio_context);
 }
 
@@ -2845,17 +3699,22 @@ static BlockJob *find_block_job(const char *device, AioContext **aio_context,
     BlockBackend *blk;
     BlockDriverState *bs;
 
+    *aio_context = NULL;
+
     blk = blk_by_name(device);
     if (!blk) {
         goto notfound;
     }
-    bs = blk_bs(blk);
 
-    *aio_context = bdrv_get_aio_context(bs);
+    *aio_context = blk_get_aio_context(blk);
     aio_context_acquire(*aio_context);
 
+    if (!blk_is_available(blk)) {
+        goto notfound;
+    }
+    bs = blk_bs(blk);
+
     if (!bs->job) {
-        aio_context_release(*aio_context);
         goto notfound;
     }
 
@@ -2864,7 +3723,10 @@ static BlockJob *find_block_job(const char *device, AioContext **aio_context,
 notfound:
     error_set(errp, ERROR_CLASS_DEVICE_NOT_ACTIVE,
               "No active block job on device '%s'", device);
-    *aio_context = NULL;
+    if (*aio_context) {
+        aio_context_release(*aio_context);
+        *aio_context = NULL;
+    }
     return NULL;
 }
 
@@ -2971,11 +3833,16 @@ void qmp_change_backing_file(const char *device,
                   "Device '%s' not found", device);
         return;
     }
-    bs = blk_bs(blk);
 
-    aio_context = bdrv_get_aio_context(bs);
+    aio_context = blk_get_aio_context(blk);
     aio_context_acquire(aio_context);
 
+    if (!blk_is_available(blk)) {
+        error_setg(errp, "Device '%s' has no medium", device);
+        goto out;
+    }
+    bs = blk_bs(blk);
+
     image_bs = bdrv_lookup_bs(NULL, image_node_name, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
@@ -3039,20 +3906,46 @@ out:
     aio_context_release(aio_context);
 }
 
+void hmp_drive_add_node(Monitor *mon, const char *optstr)
+{
+    QemuOpts *opts;
+    QDict *qdict;
+    Error *local_err = NULL;
+
+    opts = qemu_opts_parse_noisily(&qemu_drive_opts, optstr, false);
+    if (!opts) {
+        return;
+    }
+
+    qdict = qemu_opts_to_qdict(opts, NULL);
+
+    if (!qdict_get_try_str(qdict, "node-name")) {
+        QDECREF(qdict);
+        error_report("'node-name' needs to be specified");
+        goto out;
+    }
+
+    BlockDriverState *bs = bds_tree_init(qdict, &local_err);
+    if (!bs) {
+        error_report_err(local_err);
+        goto out;
+    }
+
+    QTAILQ_INSERT_TAIL(&monitor_bdrv_states, bs, monitor_list);
+
+out:
+    qemu_opts_del(opts);
+}
+
 void qmp_blockdev_add(BlockdevOptions *options, Error **errp)
 {
     QmpOutputVisitor *ov = qmp_output_visitor_new();
-    BlockBackend *blk;
+    BlockDriverState *bs;
+    BlockBackend *blk = NULL;
     QObject *obj;
     QDict *qdict;
     Error *local_err = NULL;
 
-    /* Require an ID in the top level */
-    if (!options->has_id) {
-        error_setg(errp, "Block device needs an ID");
-        goto fail;
-    }
-
     /* TODO Sort it out in raw-posix and drive_new(): Reject aio=native with
      * cache.direct=false instead of silently switching to aio=threads, except
      * when called from drive_new().
@@ -3068,8 +3961,8 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp)
         }
     }
 
-    visit_type_BlockdevOptions(qmp_output_get_visitor(ov),
-                               &options, NULL, &local_err);
+    visit_type_BlockdevOptions(qmp_output_get_visitor(ov), NULL, &options,
+                               &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
         goto fail;
@@ -3080,14 +3973,37 @@ void qmp_blockdev_add(BlockdevOptions *options, Error **errp)
 
     qdict_flatten(qdict);
 
-    blk = blockdev_init(NULL, qdict, &local_err);
-    if (local_err) {
-        error_propagate(errp, local_err);
-        goto fail;
+    if (options->has_id) {
+        blk = blockdev_init(NULL, qdict, &local_err);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            goto fail;
+        }
+
+        bs = blk_bs(blk);
+    } else {
+        if (!qdict_get_try_str(qdict, "node-name")) {
+            error_setg(errp, "'id' and/or 'node-name' need to be specified for "
+                       "the root node");
+            goto fail;
+        }
+
+        bs = bds_tree_init(qdict, errp);
+        if (!bs) {
+            goto fail;
+        }
+
+        QTAILQ_INSERT_TAIL(&monitor_bdrv_states, bs, monitor_list);
     }
 
-    if (bdrv_key_required(blk_bs(blk))) {
-        blk_unref(blk);
+    if (bs && bdrv_key_required(bs)) {
+        if (blk) {
+            monitor_remove_blk(blk);
+            blk_unref(blk);
+        } else {
+            QTAILQ_REMOVE(&monitor_bdrv_states, bs, monitor_list);
+            bdrv_unref(bs);
+        }
         error_setg(errp, "blockdev-add doesn't support encrypted devices");
         goto fail;
     }
@@ -3096,6 +4012,86 @@ fail:
     qmp_output_visitor_cleanup(ov);
 }
 
+void qmp_x_blockdev_del(bool has_id, const char *id,
+                        bool has_node_name, const char *node_name, Error **errp)
+{
+    AioContext *aio_context;
+    BlockBackend *blk;
+    BlockDriverState *bs;
+
+    if (has_id && has_node_name) {
+        error_setg(errp, "Only one of id and node-name must be specified");
+        return;
+    } else if (!has_id && !has_node_name) {
+        error_setg(errp, "No block device specified");
+        return;
+    }
+
+    if (has_id) {
+        /* blk_by_name() never returns a BB that is not owned by the monitor */
+        blk = blk_by_name(id);
+        if (!blk) {
+            error_setg(errp, "Cannot find block backend %s", id);
+            return;
+        }
+        if (blk_legacy_dinfo(blk)) {
+            error_setg(errp, "Deleting block backend added with drive-add"
+                       " is not supported");
+            return;
+        }
+        if (blk_get_refcnt(blk) > 1) {
+            error_setg(errp, "Block backend %s is in use", id);
+            return;
+        }
+        bs = blk_bs(blk);
+        aio_context = blk_get_aio_context(blk);
+    } else {
+        bs = bdrv_find_node(node_name);
+        if (!bs) {
+            error_setg(errp, "Cannot find node %s", node_name);
+            return;
+        }
+        blk = bs->blk;
+        if (blk) {
+            error_setg(errp, "Node %s is in use by %s",
+                       node_name, blk_name(blk));
+            return;
+        }
+        aio_context = bdrv_get_aio_context(bs);
+    }
+
+    aio_context_acquire(aio_context);
+
+    if (bs) {
+        if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_DRIVE_DEL, errp)) {
+            goto out;
+        }
+
+        if (!blk && !bs->monitor_list.tqe_prev) {
+            error_setg(errp, "Node %s is not owned by the monitor",
+                       bs->node_name);
+            goto out;
+        }
+
+        if (bs->refcnt > 1) {
+            error_setg(errp, "Block device %s is in use",
+                       bdrv_get_device_or_node_name(bs));
+            goto out;
+        }
+    }
+
+    if (blk) {
+        monitor_remove_blk(blk);
+        blk_unref(blk);
+    } else {
+        QTAILQ_REMOVE(&monitor_bdrv_states, bs, monitor_list);
+        bdrv_unref(bs);
+    }
+
+out:
+    aio_context_release(aio_context);
+}
+
 BlockJobInfoList *qmp_query_block_jobs(Error **errp)
 {
     BlockJobInfoList *head = NULL, **p_next = &head;
@@ -3131,22 +4127,14 @@ QemuOptsList qemu_common_drive_opts = {
             .name = "discard",
             .type = QEMU_OPT_STRING,
             .help = "discard operation (ignore/off, unmap/on)",
-        },{
-            .name = BDRV_OPT_CACHE_WB,
-            .type = QEMU_OPT_BOOL,
-            .help = "enables writeback mode for any caches",
-        },{
-            .name = BDRV_OPT_CACHE_DIRECT,
-            .type = QEMU_OPT_BOOL,
-            .help = "enables use of O_DIRECT (bypass the host page cache)",
-        },{
-            .name = BDRV_OPT_CACHE_NO_FLUSH,
-            .type = QEMU_OPT_BOOL,
-            .help = "ignore any flush requests for the device",
         },{
             .name = "aio",
             .type = QEMU_OPT_STRING,
             .help = "host AIO implementation (threads, native)",
+        },{
+            .name = BDRV_OPT_CACHE_WB,
+            .type = QEMU_OPT_BOOL,
+            .help = "Enable writeback mode",
         },{
             .name = "format",
             .type = QEMU_OPT_STRING,
@@ -3211,6 +4199,30 @@ QemuOptsList qemu_common_drive_opts = {
             .name = "throttling.bps-write-max",
             .type = QEMU_OPT_NUMBER,
             .help = "total bytes write burst",
+        },{
+            .name = "throttling.iops-total-max-length",
+            .type = QEMU_OPT_NUMBER,
+            .help = "length of the iops-total-max burst period, in seconds",
+        },{
+            .name = "throttling.iops-read-max-length",
+            .type = QEMU_OPT_NUMBER,
+            .help = "length of the iops-read-max burst period, in seconds",
+        },{
+            .name = "throttling.iops-write-max-length",
+            .type = QEMU_OPT_NUMBER,
+            .help = "length of the iops-write-max burst period, in seconds",
+        },{
+            .name = "throttling.bps-total-max-length",
+            .type = QEMU_OPT_NUMBER,
+            .help = "length of the bps-total-max burst period, in seconds",
+        },{
+            .name = "throttling.bps-read-max-length",
+            .type = QEMU_OPT_NUMBER,
+            .help = "length of the bps-read-max burst period, in seconds",
+        },{
+            .name = "throttling.bps-write-max-length",
+            .type = QEMU_OPT_NUMBER,
+            .help = "length of the bps-write-max burst period, in seconds",
         },{
             .name = "throttling.iops-size",
             .type = QEMU_OPT_NUMBER,
@@ -3227,6 +4239,45 @@ QemuOptsList qemu_common_drive_opts = {
             .name = "detect-zeroes",
             .type = QEMU_OPT_STRING,
             .help = "try to optimize zero writes (off, on, unmap)",
+        },{
+            .name = "stats-account-invalid",
+            .type = QEMU_OPT_BOOL,
+            .help = "whether to account for invalid I/O operations "
+                    "in the statistics",
+        },{
+            .name = "stats-account-failed",
+            .type = QEMU_OPT_BOOL,
+            .help = "whether to account for failed I/O operations "
+                    "in the statistics",
+        },
+        { /* end of list */ }
+    },
+};
+
+static QemuOptsList qemu_root_bds_opts = {
+    .name = "root-bds",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_root_bds_opts.head),
+    .desc = {
+        {
+            .name = "discard",
+            .type = QEMU_OPT_STRING,
+            .help = "discard operation (ignore/off, unmap/on)",
+        },{
+            .name = "aio",
+            .type = QEMU_OPT_STRING,
+            .help = "host AIO implementation (threads, native)",
+        },{
+            .name = "read-only",
+            .type = QEMU_OPT_BOOL,
+            .help = "open drive file as read-only",
+        },{
+            .name = "copy-on-read",
+            .type = QEMU_OPT_BOOL,
+            .help = "copy read data from backing file into image file",
+        },{
+            .name = "detect-zeroes",
+            .type = QEMU_OPT_STRING,
+            .help = "try to optimize zero writes (off, on, unmap)",
         },
         { /* end of list */ }
     },