Merge remote-tracking branch 'kwolf/for-anthony' into staging

* kwolf/for-anthony: (43 commits)
  qcow2: Factor out handle_dependencies()
  qcow2: Execute run_dependent_requests() without lock
  qcow2: Enable dirty flag in qcow2_alloc_cluster_link_l2
  qcow2: Allocate l2meta only for cluster allocations
  qcow2: Drop l2meta.cluster_offset
  qcow2: Allocate l2meta dynamically
  qcow2: Introduce Qcow2COWRegion
  qcow2: Round QCowL2Meta.offset down to cluster boundary
  atapi: reset cdrom tray statuses on ide_reset
  qemu-iotests: Test concurrent cluster allocations
  qcow2: Move BLKDBG_EVENT out of the lock
  qemu-io: Add AIO debugging commands
  blkdebug: Implement suspend/resume of AIO requests
  blkdebug: Factor out remove_rule()
  blkdebug: Allow usage without config file
  create new function: qemu_opt_set_number
  use qemu_opts_create_nofail
  introduce qemu_opts_create_nofail function
  qemu-option: qemu_opt_set_bool(): fix code duplication
  qemu-option: qemu_opts_validate(): fix duplicated code
  ...

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

52 files changed, 1343 insertions, 443 deletions

diff --git a/async.c b/async.c
index 3f0e8f3..41ae0c1 100644
--- a/async.c
+++ b/async.c
@@ -215,8 +215,3 @@ void aio_context_unref(AioContext *ctx)
 {
     g_source_unref(&ctx->source);
 }
-
-void aio_flush(AioContext *ctx)
-{
-    while (aio_poll(ctx, true));
-}
diff --git a/block.c b/block.c
index c05875f..0668c4b 100644
--- a/block.c
+++ b/block.c
@@ -518,22 +518,16 @@ BlockDriver *bdrv_find_protocol(const char *filename)
     return NULL;
 }
 
-static int find_image_format(const char *filename, BlockDriver **pdrv)
+static int find_image_format(BlockDriverState *bs, const char *filename,
+                             BlockDriver **pdrv)
 {
-    int ret, score, score_max;
+    int score, score_max;
     BlockDriver *drv1, *drv;
     uint8_t buf[2048];
-    BlockDriverState *bs;
-
-    ret = bdrv_file_open(&bs, filename, 0);
-    if (ret < 0) {
-        *pdrv = NULL;
-        return ret;
-    }
+    int ret = 0;
 
     /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
     if (bs->sg || !bdrv_is_inserted(bs)) {
-        bdrv_delete(bs);
         drv = bdrv_find_format("raw");
         if (!drv) {
             ret = -ENOENT;
@@ -543,7 +537,6 @@ static int find_image_format(const char *filename, BlockDriver **pdrv)
     }
 
     ret = bdrv_pread(bs, 0, buf, sizeof(buf));
-    bdrv_delete(bs);
     if (ret < 0) {
         *pdrv = NULL;
         return ret;
@@ -634,10 +627,31 @@ void bdrv_disable_copy_on_read(BlockDriverState *bs)
     bs->copy_on_read--;
 }
 
+static int bdrv_open_flags(BlockDriverState *bs, int flags)
+{
+    int open_flags = flags | BDRV_O_CACHE_WB;
+
+    /*
+     * Clear flags that are internal to the block layer before opening the
+     * image.
+     */
+    open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
+
+    /*
+     * Snapshots should be writable.
+     */
+    if (bs->is_temporary) {
+        open_flags |= BDRV_O_RDWR;
+    }
+
+    return open_flags;
+}
+
 /*
  * Common part for opening disk images and files
  */
-static int bdrv_open_common(BlockDriverState *bs, const char *filename,
+static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file,
+    const char *filename,
     int flags, BlockDriver *drv)
 {
     int ret, open_flags;
@@ -665,31 +679,22 @@ static int bdrv_open_common(BlockDriverState *bs, const char *filename,
     bs->opaque = g_malloc0(drv->instance_size);
 
     bs->enable_write_cache = !!(flags & BDRV_O_CACHE_WB);
-    open_flags = flags | BDRV_O_CACHE_WB;
-
-    /*
-     * Clear flags that are internal to the block layer before opening the
-     * image.
-     */
-    open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
-
-    /*
-     * Snapshots should be writable.
-     */
-    if (bs->is_temporary) {
-        open_flags |= BDRV_O_RDWR;
-    }
+    open_flags = bdrv_open_flags(bs, flags);
 
     bs->read_only = !(open_flags & BDRV_O_RDWR);
 
     /* Open the image, either directly or using a protocol */
     if (drv->bdrv_file_open) {
-        ret = drv->bdrv_file_open(bs, filename, open_flags);
-    } else {
-        ret = bdrv_file_open(&bs->file, filename, open_flags);
-        if (ret >= 0) {
-            ret = drv->bdrv_open(bs, open_flags);
+        if (file != NULL) {
+            bdrv_swap(file, bs);
+            ret = 0;
+        } else {
+            ret = drv->bdrv_file_open(bs, filename, open_flags);
         }
+    } else {
+        assert(file != NULL);
+        bs->file = file;
+        ret = drv->bdrv_open(bs, open_flags);
     }
 
     if (ret < 0) {
@@ -709,10 +714,7 @@ static int bdrv_open_common(BlockDriverState *bs, const char *filename,
     return 0;
 
 free_and_fail:
-    if (bs->file) {
-        bdrv_delete(bs->file);
-        bs->file = NULL;
-    }
+    bs->file = NULL;
     g_free(bs->opaque);
     bs->opaque = NULL;
     bs->drv = NULL;
@@ -734,7 +736,7 @@ int bdrv_file_open(BlockDriverState **pbs, const char *filename, int flags)
     }
 
     bs = bdrv_new("");
-    ret = bdrv_open_common(bs, filename, flags, drv);
+    ret = bdrv_open_common(bs, NULL, filename, flags, drv);
     if (ret < 0) {
         bdrv_delete(bs);
         return ret;
@@ -789,6 +791,7 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
     int ret;
     /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
     char tmp_filename[PATH_MAX + 1];
+    BlockDriverState *file = NULL;
 
     if (flags & BDRV_O_SNAPSHOT) {
         BlockDriverState *bs1;
@@ -848,25 +851,36 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
         bs->is_temporary = 1;
     }
 
+    /* Open image file without format layer */
+    if (flags & BDRV_O_RDWR) {
+        flags |= BDRV_O_ALLOW_RDWR;
+    }
+
+    ret = bdrv_file_open(&file, filename, bdrv_open_flags(bs, flags));
+    if (ret < 0) {
+        return ret;
+    }
+
     /* Find the right image format driver */
     if (!drv) {
-        ret = find_image_format(filename, &drv);
+        ret = find_image_format(file, filename, &drv);
     }
 
     if (!drv) {
         goto unlink_and_fail;
     }
 
-    if (flags & BDRV_O_RDWR) {
-        flags |= BDRV_O_ALLOW_RDWR;
-    }
-
     /* Open the image */
-    ret = bdrv_open_common(bs, filename, flags, drv);
+    ret = bdrv_open_common(bs, file, filename, flags, drv);
     if (ret < 0) {
         goto unlink_and_fail;
     }
 
+    if (bs->file != file) {
+        bdrv_delete(file);
+        file = NULL;
+    }
+
     /* If there is a backing file, use it */
     if ((flags & BDRV_O_NO_BACKING) == 0) {
         ret = bdrv_open_backing_file(bs);
@@ -888,6 +902,9 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags,
     return 0;
 
 unlink_and_fail:
+    if (file != NULL) {
+        bdrv_delete(file);
+    }
     if (bs->is_temporary) {
         unlink(filename);
     }
@@ -3028,7 +3045,46 @@ void bdrv_debug_event(BlockDriverState *bs, BlkDebugEvent event)
     }
 
     drv->bdrv_debug_event(bs, event);
+}
+
+int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
+                          const char *tag)
+{
+    while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) {
+        bs = bs->file;
+    }
+
+    if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) {
+        return bs->drv->bdrv_debug_breakpoint(bs, event, tag);
+    }
 
+    return -ENOTSUP;
+}
+
+int bdrv_debug_resume(BlockDriverState *bs, const char *tag)
+{
+    while (bs && bs->drv && !bs->drv->bdrv_debug_resume) {
+        bs = bs->file;
+    }
+
+    if (bs && bs->drv && bs->drv->bdrv_debug_resume) {
+        return bs->drv->bdrv_debug_resume(bs, tag);
+    }
+
+    return -ENOTSUP;
+}
+
+bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag)
+{
+    while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) {
+        bs = bs->file;
+    }
+
+    if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) {
+        return bs->drv->bdrv_debug_is_suspended(bs, tag);
+    }
+
+    return false;
 }
 
 /**************************************************************/
@@ -3778,12 +3834,20 @@ typedef struct BlockDriverAIOCBCoroutine {
     BlockDriverAIOCB common;
     BlockRequest req;
     bool is_write;
+    bool *done;
     QEMUBH* bh;
 } BlockDriverAIOCBCoroutine;
 
 static void bdrv_aio_co_cancel_em(BlockDriverAIOCB *blockacb)
 {
-    qemu_aio_flush();
+    BlockDriverAIOCBCoroutine *acb =
+        container_of(blockacb, BlockDriverAIOCBCoroutine, common);
+    bool done = false;
+
+    acb->done = &done;
+    while (!done) {
+        qemu_aio_wait();
+    }
 }
 
 static const AIOCBInfo bdrv_em_co_aiocb_info = {
@@ -3796,6 +3860,11 @@ static void bdrv_co_em_bh(void *opaque)
     BlockDriverAIOCBCoroutine *acb = opaque;
 
     acb->common.cb(acb->common.opaque, acb->req.error);
+
+    if (acb->done) {
+        *acb->done = true;
+    }
+
     qemu_bh_delete(acb->bh);
     qemu_aio_release(acb);
 }
@@ -3834,6 +3903,7 @@ static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
     acb->req.nb_sectors = nb_sectors;
     acb->req.qiov = qiov;
     acb->is_write = is_write;
+    acb->done = NULL;
 
     co = qemu_coroutine_create(bdrv_co_do_rw);
     qemu_coroutine_enter(co, acb);
@@ -3860,6 +3930,8 @@ BlockDriverAIOCB *bdrv_aio_flush(BlockDriverState *bs,
     BlockDriverAIOCBCoroutine *acb;
 
     acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque);
+    acb->done = NULL;
+
     co = qemu_coroutine_create(bdrv_aio_flush_co_entry);
     qemu_coroutine_enter(co, acb);
 
@@ -3888,6 +3960,7 @@ BlockDriverAIOCB *bdrv_aio_discard(BlockDriverState *bs,
     acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque);
     acb->req.sector = sector_num;
     acb->req.nb_sectors = nb_sectors;
+    acb->done = NULL;
     co = qemu_coroutine_create(bdrv_aio_discard_co_entry);
     qemu_coroutine_enter(co, acb);
 
@@ -4408,9 +4481,9 @@ bdrv_acct_done(BlockDriverState *bs, BlockAcctCookie *cookie)
     bs->total_time_ns[cookie->type] += get_clock() - cookie->start_time_ns;
 }
 
-int bdrv_img_create(const char *filename, const char *fmt,
-                    const char *base_filename, const char *base_fmt,
-                    char *options, uint64_t img_size, int flags)
+void bdrv_img_create(const char *filename, const char *fmt,
+                     const char *base_filename, const char *base_fmt,
+                     char *options, uint64_t img_size, int flags, Error **errp)
 {
     QEMUOptionParameter *param = NULL, *create_options = NULL;
     QEMUOptionParameter *backing_fmt, *backing_file, *size;
@@ -4422,16 +4495,14 @@ int bdrv_img_create(const char *filename, const char *fmt,
     /* Find driver and parse its options */
     drv = bdrv_find_format(fmt);
     if (!drv) {
-        error_report("Unknown file format '%s'", fmt);
-        ret = -EINVAL;
-        goto out;
+        error_setg(errp, "Unknown file format '%s'", fmt);
+        return;
     }
 
     proto_drv = bdrv_find_protocol(filename);
     if (!proto_drv) {
-        error_report("Unknown protocol '%s'", filename);
-        ret = -EINVAL;
-        goto out;
+        error_setg(errp, "Unknown protocol '%s'", filename);
+        return;
     }
 
     create_options = append_option_parameters(create_options,
@@ -4448,8 +4519,7 @@ int bdrv_img_create(const char *filename, const char *fmt,
     if (options) {
         param = parse_option_parameters(options, create_options, param);
         if (param == NULL) {
-            error_report("Invalid options for file format '%s'.", fmt);
-            ret = -EINVAL;
+            error_setg(errp, "Invalid options for file format '%s'.", fmt);
             goto out;
         }
     }
@@ -4457,18 +4527,16 @@ int bdrv_img_create(const char *filename, const char *fmt,
     if (base_filename) {
         if (set_option_parameter(param, BLOCK_OPT_BACKING_FILE,
                                  base_filename)) {
-            error_report("Backing file not supported for file format '%s'",
-                         fmt);
-            ret = -EINVAL;
+            error_setg(errp, "Backing file not supported for file format '%s'",
+                       fmt);
             goto out;
         }
     }
 
     if (base_fmt) {
         if (set_option_parameter(param, BLOCK_OPT_BACKING_FMT, base_fmt)) {
-            error_report("Backing file format not supported for file "
-                         "format '%s'", fmt);
-            ret = -EINVAL;
+            error_setg(errp, "Backing file format not supported for file "
+                             "format '%s'", fmt);
             goto out;
         }
     }
@@ -4476,9 +4544,8 @@ int bdrv_img_create(const char *filename, const char *fmt,
     backing_file = get_option_parameter(param, BLOCK_OPT_BACKING_FILE);
     if (backing_file && backing_file->value.s) {
         if (!strcmp(filename, backing_file->value.s)) {
-            error_report("Error: Trying to create an image with the "
-                         "same filename as the backing file");
-            ret = -EINVAL;
+            error_setg(errp, "Error: Trying to create an image with the "
+                             "same filename as the backing file");
             goto out;
         }
     }
@@ -4487,9 +4554,8 @@ int bdrv_img_create(const char *filename, const char *fmt,
     if (backing_fmt && backing_fmt->value.s) {
         backing_drv = bdrv_find_format(backing_fmt->value.s);
         if (!backing_drv) {
-            error_report("Unknown backing file format '%s'",
-                         backing_fmt->value.s);
-            ret = -EINVAL;
+            error_setg(errp, "Unknown backing file format '%s'",
+                       backing_fmt->value.s);
             goto out;
         }
     }
@@ -4511,7 +4577,8 @@ int bdrv_img_create(const char *filename, const char *fmt,
 
             ret = bdrv_open(bs, backing_file->value.s, back_flags, backing_drv);
             if (ret < 0) {
-                error_report("Could not open '%s'", backing_file->value.s);
+                error_setg_errno(errp, -ret, "Could not open '%s'",
+                                 backing_file->value.s);
                 goto out;
             }
             bdrv_get_geometry(bs, &size);
@@ -4520,8 +4587,7 @@ int bdrv_img_create(const char *filename, const char *fmt,
             snprintf(buf, sizeof(buf), "%" PRId64, size);
             set_option_parameter(param, BLOCK_OPT_SIZE, buf);
         } else {
-            error_report("Image creation needs a size parameter");
-            ret = -EINVAL;
+            error_setg(errp, "Image creation needs a size parameter");
             goto out;
         }
     }
@@ -4531,17 +4597,16 @@ int bdrv_img_create(const char *filename, const char *fmt,
     puts("");
 
     ret = bdrv_create(drv, filename, param);
-
     if (ret < 0) {
         if (ret == -ENOTSUP) {
-            error_report("Formatting or formatting option not supported for "
-                         "file format '%s'", fmt);
+            error_setg(errp,"Formatting or formatting option not supported for "
+                            "file format '%s'", fmt);
         } else if (ret == -EFBIG) {
-            error_report("The image size is too large for file format '%s'",
-                         fmt);
+            error_setg(errp, "The image size is too large for file format '%s'",
+                       fmt);
         } else {
-            error_report("%s: error while creating %s: %s", filename, fmt,
-                         strerror(-ret));
+            error_setg(errp, "%s: error while creating %s: %s", filename, fmt,
+                       strerror(-ret));
         }
     }
 
@@ -4552,6 +4617,4 @@ out:
     if (bs) {
         bdrv_delete(bs);
     }
-
-    return ret;
 }
diff --git a/block.h b/block.h
index 722c620..893448a 100644
--- a/block.h
+++ b/block.h
@@ -343,9 +343,9 @@ int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
                       int64_t pos, int size);
 
-int bdrv_img_create(const char *filename, const char *fmt,
-                    const char *base_filename, const char *base_fmt,
-                    char *options, uint64_t img_size, int flags);
+void bdrv_img_create(const char *filename, const char *fmt,
+                     const char *base_filename, const char *base_fmt,
+                     char *options, uint64_t img_size, int flags, Error **errp);
 
 void bdrv_set_buffer_alignment(BlockDriverState *bs, int align);
 void *qemu_blockalign(BlockDriverState *bs, size_t size);
@@ -431,4 +431,9 @@ typedef enum {
 #define BLKDBG_EVENT(bs, evt) bdrv_debug_event(bs, evt)
 void bdrv_debug_event(BlockDriverState *bs, BlkDebugEvent event);
 
+int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
+                           const char *tag);
+int bdrv_debug_resume(BlockDriverState *bs, const char *tag);
+bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag);
+
 #endif
diff --git a/block/blkdebug.c b/block/blkdebug.c
index d61ece8..294e983 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -29,8 +29,10 @@
 typedef struct BDRVBlkdebugState {
     int state;
     int new_state;
+
     QLIST_HEAD(, BlkdebugRule) rules[BLKDBG_EVENT_MAX];
     QSIMPLEQ_HEAD(, BlkdebugRule) active_rules;
+    QLIST_HEAD(, BlkdebugSuspendedReq) suspended_reqs;
 } BDRVBlkdebugState;
 
 typedef struct BlkdebugAIOCB {
@@ -39,6 +41,12 @@ typedef struct BlkdebugAIOCB {
     int ret;
 } BlkdebugAIOCB;
 
+typedef struct BlkdebugSuspendedReq {
+    Coroutine *co;
+    char *tag;
+    QLIST_ENTRY(BlkdebugSuspendedReq) next;
+} BlkdebugSuspendedReq;
+
 static void blkdebug_aio_cancel(BlockDriverAIOCB *blockacb);
 
 static const AIOCBInfo blkdebug_aiocb_info = {
@@ -49,6 +57,7 @@ static const AIOCBInfo blkdebug_aiocb_info = {
 enum {
     ACTION_INJECT_ERROR,
     ACTION_SET_STATE,
+    ACTION_SUSPEND,
 };
 
 typedef struct BlkdebugRule {
@@ -65,6 +74,9 @@ typedef struct BlkdebugRule {
         struct {
             int new_state;
         } set_state;
+        struct {
+            char *tag;
+        } suspend;
     } options;
     QLIST_ENTRY(BlkdebugRule) next;
     QSIMPLEQ_ENTRY(BlkdebugRule) active_next;
@@ -226,6 +238,11 @@ static int add_rule(QemuOpts *opts, void *opaque)
         rule->options.set_state.new_state =
             qemu_opt_get_number(opts, "new_state", 0);
         break;
+
+    case ACTION_SUSPEND:
+        rule->options.suspend.tag =
+            g_strdup(qemu_opt_get(opts, "tag"));
+        break;
     };
 
     /* Add the rule */
@@ -234,12 +251,32 @@ static int add_rule(QemuOpts *opts, void *opaque)
     return 0;
 }
 
+static void remove_rule(BlkdebugRule *rule)
+{
+    switch (rule->action) {
+    case ACTION_INJECT_ERROR:
+    case ACTION_SET_STATE:
+        break;
+    case ACTION_SUSPEND:
+        g_free(rule->options.suspend.tag);
+        break;
+    }
+
+    QLIST_REMOVE(rule, next);
+    g_free(rule);
+}
+
 static int read_config(BDRVBlkdebugState *s, const char *filename)
 {
     FILE *f;
     int ret;
     struct add_rule_data d;
 
+    /* Allow usage without config file */
+    if (!*filename) {
+        return 0;
+    }
+
     f = fopen(filename, "r");
     if (f == NULL) {
         return -errno;
@@ -389,6 +426,7 @@ static BlockDriverAIOCB *blkdebug_aio_writev(BlockDriverState *bs,
     return bdrv_aio_writev(bs->file, sector_num, qiov, nb_sectors, cb, opaque);
 }
 
+
 static void blkdebug_close(BlockDriverState *bs)
 {
     BDRVBlkdebugState *s = bs->opaque;
@@ -397,12 +435,32 @@ static void blkdebug_close(BlockDriverState *bs)
 
     for (i = 0; i < BLKDBG_EVENT_MAX; i++) {
         QLIST_FOREACH_SAFE(rule, &s->rules[i], next, next) {
-            QLIST_REMOVE(rule, next);
-            g_free(rule);
+            remove_rule(rule);
         }
     }
 }
 
+static void suspend_request(BlockDriverState *bs, BlkdebugRule *rule)
+{
+    BDRVBlkdebugState *s = bs->opaque;
+    BlkdebugSuspendedReq r;
+
+    r = (BlkdebugSuspendedReq) {
+        .co         = qemu_coroutine_self(),
+        .tag        = g_strdup(rule->options.suspend.tag),
+    };
+
+    remove_rule(rule);
+    QLIST_INSERT_HEAD(&s->suspended_reqs, &r, next);
+
+    printf("blkdebug: Suspended request '%s'\n", r.tag);
+    qemu_coroutine_yield();
+    printf("blkdebug: Resuming request '%s'\n", r.tag);
+
+    QLIST_REMOVE(&r, next);
+    g_free(r.tag);
+}
+
 static bool process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,
     bool injected)
 {
@@ -426,6 +484,10 @@ static bool process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,
     case ACTION_SET_STATE:
         s->new_state = rule->options.set_state.new_state;
         break;
+
+    case ACTION_SUSPEND:
+        suspend_request(bs, rule);
+        break;
     }
     return injected;
 }
@@ -433,19 +495,72 @@ static bool process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,
 static void blkdebug_debug_event(BlockDriverState *bs, BlkDebugEvent event)
 {
     BDRVBlkdebugState *s = bs->opaque;
-    struct BlkdebugRule *rule;
+    struct BlkdebugRule *rule, *next;
     bool injected;
 
     assert((int)event >= 0 && event < BLKDBG_EVENT_MAX);
 
     injected = false;
     s->new_state = s->state;
-    QLIST_FOREACH(rule, &s->rules[event], next) {
+    QLIST_FOREACH_SAFE(rule, &s->rules[event], next, next) {
         injected = process_rule(bs, rule, injected);
     }
     s->state = s->new_state;
 }
 
+static int blkdebug_debug_breakpoint(BlockDriverState *bs, const char *event,
+                                     const char *tag)
+{
+    BDRVBlkdebugState *s = bs->opaque;
+    struct BlkdebugRule *rule;
+    BlkDebugEvent blkdebug_event;
+
+    if (get_event_by_name(event, &blkdebug_event) < 0) {
+        return -ENOENT;
+    }
+
+
+    rule = g_malloc(sizeof(*rule));
+    *rule = (struct BlkdebugRule) {
+        .event  = blkdebug_event,
+        .action = ACTION_SUSPEND,
+        .state  = 0,
+        .options.suspend.tag = g_strdup(tag),
+    };
+
+    QLIST_INSERT_HEAD(&s->rules[blkdebug_event], rule, next);
+
+    return 0;
+}
+
+static int blkdebug_debug_resume(BlockDriverState *bs, const char *tag)
+{
+    BDRVBlkdebugState *s = bs->opaque;
+    BlkdebugSuspendedReq *r;
+
+    QLIST_FOREACH(r, &s->suspended_reqs, next) {
+        if (!strcmp(r->tag, tag)) {
+            qemu_coroutine_enter(r->co, NULL);
+            return 0;
+        }
+    }
+    return -ENOENT;
+}
+
+
+static bool blkdebug_debug_is_suspended(BlockDriverState *bs, const char *tag)
+{
+    BDRVBlkdebugState *s = bs->opaque;
+    BlkdebugSuspendedReq *r;
+
+    QLIST_FOREACH(r, &s->suspended_reqs, next) {
+        if (!strcmp(r->tag, tag)) {
+            return true;
+        }
+    }
+    return false;
+}
+
 static int64_t blkdebug_getlength(BlockDriverState *bs)
 {
     return bdrv_getlength(bs->file);
@@ -464,7 +579,10 @@ static BlockDriver bdrv_blkdebug = {
     .bdrv_aio_readv     = blkdebug_aio_readv,
     .bdrv_aio_writev    = blkdebug_aio_writev,
 
-    .bdrv_debug_event   = blkdebug_debug_event,
+    .bdrv_debug_event           = blkdebug_debug_event,
+    .bdrv_debug_breakpoint      = blkdebug_debug_breakpoint,
+    .bdrv_debug_resume          = blkdebug_debug_resume,
+    .bdrv_debug_is_suspended    = blkdebug_debug_is_suspended,
 };
 
 static void bdrv_blkdebug_init(void)
diff --git a/block/commit.c b/block/commit.c
index fae7958..e2bb1e2 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -103,7 +103,7 @@ static void coroutine_fn commit_run(void *opaque)
 
 wait:
         /* Note that even when no rate limit is applied we need to yield
-         * with no pending I/O here so that qemu_aio_flush() returns.
+         * with no pending I/O here so that bdrv_drain_all() returns.
          */
         block_job_sleep_ns(&s->common, rt_clock, delay_ns);
         if (block_job_is_cancelled(&s->common)) {
diff --git a/block/mirror.c b/block/mirror.c
index d6618a4..b1f5d4fa 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -205,7 +205,7 @@ static void coroutine_fn mirror_run(void *opaque)
             }
 
             /* Note that even when no rate limit is applied we need to yield
-             * with no pending I/O here so that qemu_aio_flush() returns.
+             * with no pending I/O here so that bdrv_drain_all() returns.
              */
             block_job_sleep_ns(&s->common, rt_clock, delay_ns);
             if (block_job_is_cancelled(&s->common)) {
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index e179211..468ef1b 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -615,57 +615,67 @@ uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
     return cluster_offset;
 }
 
-int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
+static int perform_cow(BlockDriverState *bs, QCowL2Meta *m, Qcow2COWRegion *r)
 {
     BDRVQcowState *s = bs->opaque;
-    int i, j = 0, l2_index, ret;
-    uint64_t *old_cluster, start_sect, *l2_table;
-    uint64_t cluster_offset = m->alloc_offset;
-    bool cow = false;
-
-    trace_qcow2_cluster_link_l2(qemu_coroutine_self(), m->nb_clusters);
+    int ret;
 
-    if (m->nb_clusters == 0)
+    if (r->nb_sectors == 0) {
         return 0;
+    }
 
-    old_cluster = g_malloc(m->nb_clusters * sizeof(uint64_t));
+    qemu_co_mutex_unlock(&s->lock);
+    ret = copy_sectors(bs, m->offset / BDRV_SECTOR_SIZE, m->alloc_offset,
+                       r->offset / BDRV_SECTOR_SIZE,
+                       r->offset / BDRV_SECTOR_SIZE + r->nb_sectors);
+    qemu_co_mutex_lock(&s->lock);
 
-    /* copy content of unmodified sectors */
-    start_sect = (m->offset & ~(s->cluster_size - 1)) >> 9;
-    if (m->n_start) {
-        cow = true;
-        qemu_co_mutex_unlock(&s->lock);
-        ret = copy_sectors(bs, start_sect, cluster_offset, 0, m->n_start);
-        qemu_co_mutex_lock(&s->lock);
-        if (ret < 0)
-            goto err;
-    }
-
-    if (m->nb_available & (s->cluster_sectors - 1)) {
-        cow = true;
-        qemu_co_mutex_unlock(&s->lock);
-        ret = copy_sectors(bs, start_sect, cluster_offset, m->nb_available,
-                           align_offset(m->nb_available, s->cluster_sectors));
-        qemu_co_mutex_lock(&s->lock);
-        if (ret < 0)
-            goto err;
+    if (ret < 0) {
+        return ret;
     }
 
     /*
-     * Update L2 table.
-     *
      * Before we update the L2 table to actually point to the new cluster, we
      * need to be sure that the refcounts have been increased and COW was
      * handled.
      */
-    if (cow) {
-        qcow2_cache_depends_on_flush(s->l2_table_cache);
+    qcow2_cache_depends_on_flush(s->l2_table_cache);
+
+    return 0;
+}
+
+int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
+{
+    BDRVQcowState *s = bs->opaque;
+    int i, j = 0, l2_index, ret;
+    uint64_t *old_cluster, *l2_table;
+    uint64_t cluster_offset = m->alloc_offset;
+
+    trace_qcow2_cluster_link_l2(qemu_coroutine_self(), m->nb_clusters);
+    assert(m->nb_clusters > 0);
+
+    old_cluster = g_malloc(m->nb_clusters * sizeof(uint64_t));
+
+    /* copy content of unmodified sectors */
+    ret = perform_cow(bs, m, &m->cow_start);
+    if (ret < 0) {
+        goto err;
+    }
+
+    ret = perform_cow(bs, m, &m->cow_end);
+    if (ret < 0) {
+        goto err;
     }
 
+    /* Update L2 table. */
+    if (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS) {
+        qcow2_mark_dirty(bs);
+    }
     if (qcow2_need_accurate_refcounts(s)) {
         qcow2_cache_set_dependency(bs, s->l2_table_cache,
                                    s->refcount_block_cache);
     }
+
     ret = get_cluster_table(bs, m->offset, &l2_table, &l2_index);
     if (ret < 0) {
         goto err;
@@ -743,38 +753,16 @@ out:
 }
 
 /*
- * Allocates new clusters for the given guest_offset.
- *
- * At most *nb_clusters are allocated, and on return *nb_clusters is updated to
- * contain the number of clusters that have been allocated and are contiguous
- * in the image file.
- *
- * If *host_offset is non-zero, it specifies the offset in the image file at
- * which the new clusters must start. *nb_clusters can be 0 on return in this
- * case if the cluster at host_offset is already in use. If *host_offset is
- * zero, the clusters can be allocated anywhere in the image file.
- *
- * *host_offset is updated to contain the offset into the image file at which
- * the first allocated cluster starts.
- *
- * Return 0 on success and -errno in error cases. -EAGAIN means that the
- * function has been waiting for another request and the allocation must be
- * restarted, but the whole request should not be failed.
+ * Check if there already is an AIO write request in flight which allocates
+ * the same cluster. In this case we need to wait until the previous
+ * request has completed and updated the L2 table accordingly.
  */
-static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset,
-    uint64_t *host_offset, unsigned int *nb_clusters)
+static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset,
+    unsigned int *nb_clusters)
 {
     BDRVQcowState *s = bs->opaque;
     QCowL2Meta *old_alloc;
 
-    trace_qcow2_do_alloc_clusters_offset(qemu_coroutine_self(), guest_offset,
-                                         *host_offset, *nb_clusters);
-
-    /*
-     * Check if there already is an AIO write request in flight which allocates
-     * the same cluster. In this case we need to wait until the previous
-     * request has completed and updated the L2 table accordingly.
-     */
     QLIST_FOREACH(old_alloc, &s->cluster_allocs, next_in_flight) {
 
         uint64_t start = guest_offset >> s->cluster_bits;
@@ -807,6 +795,42 @@ static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset,
         abort();
     }
 
+    return 0;
+}
+
+/*
+ * Allocates new clusters for the given guest_offset.
+ *
+ * At most *nb_clusters are allocated, and on return *nb_clusters is updated to
+ * contain the number of clusters that have been allocated and are contiguous
+ * in the image file.
+ *
+ * If *host_offset is non-zero, it specifies the offset in the image file at
+ * which the new clusters must start. *nb_clusters can be 0 on return in this
+ * case if the cluster at host_offset is already in use. If *host_offset is
+ * zero, the clusters can be allocated anywhere in the image file.
+ *
+ * *host_offset is updated to contain the offset into the image file at which
+ * the first allocated cluster starts.
+ *
+ * Return 0 on success and -errno in error cases. -EAGAIN means that the
+ * function has been waiting for another request and the allocation must be
+ * restarted, but the whole request should not be failed.
+ */
+static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset,
+    uint64_t *host_offset, unsigned int *nb_clusters)
+{
+    BDRVQcowState *s = bs->opaque;
+    int ret;
+
+    trace_qcow2_do_alloc_clusters_offset(qemu_coroutine_self(), guest_offset,
+                                         *host_offset, *nb_clusters);
+
+    ret = handle_dependencies(bs, guest_offset, nb_clusters);
+    if (ret < 0) {
+        return ret;
+    }
+
     /* Allocate new clusters */
     trace_qcow2_cluster_alloc_phys(qemu_coroutine_self());
     if (*host_offset == 0) {
@@ -818,7 +842,7 @@ static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset,
         *host_offset = cluster_offset;
         return 0;
     } else {
-        int ret = qcow2_alloc_clusters_at(bs, *host_offset, *nb_clusters);
+        ret = qcow2_alloc_clusters_at(bs, *host_offset, *nb_clusters);
         if (ret < 0) {
             return ret;
         }
@@ -847,7 +871,7 @@ static int do_alloc_cluster_offset(BlockDriverState *bs, uint64_t guest_offset,
  * Return 0 on success and -errno in error cases
  */
 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
-    int n_start, int n_end, int *num, QCowL2Meta *m)
+    int n_start, int n_end, int *num, uint64_t *host_offset, QCowL2Meta **m)
 {
     BDRVQcowState *s = bs->opaque;
     int l2_index, ret, sectors;
@@ -919,12 +943,6 @@ again:
     }
 
     /* If there is something left to allocate, do that now */
-    *m = (QCowL2Meta) {
-        .cluster_offset     = cluster_offset,
-        .nb_clusters        = 0,
-    };
-    qemu_co_queue_init(&m->dependent_requests);
-
     if (nb_clusters > 0) {
         uint64_t alloc_offset;
         uint64_t alloc_cluster_offset;
@@ -957,22 +975,40 @@ again:
              *
              * avail_sectors: Number of sectors from the start of the first
              * newly allocated to the end of the last newly allocated cluster.
+             *
+             * nb_sectors: The number of sectors from the start of the first
+             * newly allocated cluster to the end of the aread that the write
+             * request actually writes to (excluding COW at the end)
              */
             int requested_sectors = n_end - keep_clusters * s->cluster_sectors;
             int avail_sectors = nb_clusters
                                 << (s->cluster_bits - BDRV_SECTOR_BITS);
+            int alloc_n_start = keep_clusters == 0 ? n_start : 0;
+            int nb_sectors = MIN(requested_sectors, avail_sectors);
+
+            if (keep_clusters == 0) {
+                cluster_offset = alloc_cluster_offset;
+            }
+
+            *m = g_malloc0(sizeof(**m));
 
-            *m = (QCowL2Meta) {
-                .cluster_offset = keep_clusters == 0 ?
-                                  alloc_cluster_offset : cluster_offset,
+            **m = (QCowL2Meta) {
                 .alloc_offset   = alloc_cluster_offset,
-                .offset         = alloc_offset,
-                .n_start        = keep_clusters == 0 ? n_start : 0,
+                .offset         = alloc_offset & ~(s->cluster_size - 1),
                 .nb_clusters    = nb_clusters,
-                .nb_available   = MIN(requested_sectors, avail_sectors),
+                .nb_available   = nb_sectors,
+
+                .cow_start = {
+                    .offset     = 0,
+                    .nb_sectors = alloc_n_start,
+                },
+                .cow_end = {
+                    .offset     = nb_sectors * BDRV_SECTOR_SIZE,
+                    .nb_sectors = avail_sectors - nb_sectors,
+                },
             };
-            qemu_co_queue_init(&m->dependent_requests);
-            QLIST_INSERT_HEAD(&s->cluster_allocs, m, next_in_flight);
+            qemu_co_queue_init(&(*m)->dependent_requests);
+            QLIST_INSERT_HEAD(&s->cluster_allocs, *m, next_in_flight);
         }
     }
 
@@ -984,12 +1020,13 @@ again:
 
     assert(sectors > n_start);
     *num = sectors - n_start;
+    *host_offset = cluster_offset;
 
     return 0;
 
 fail:
-    if (m->nb_clusters > 0) {
-        QLIST_REMOVE(m, next_in_flight);
+    if (*m && (*m)->nb_clusters > 0) {
+        QLIST_REMOVE(*m, next_in_flight);
     }
     return ret;
 }
diff --git a/block/qcow2.c b/block/qcow2.c
index c1ff31f..8520bda 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -222,7 +222,7 @@ static void report_unsupported_feature(BlockDriverState *bs,
  * updated successfully.  Therefore it is not required to check the return
  * value of this function.
  */
-static int qcow2_mark_dirty(BlockDriverState *bs)
+int qcow2_mark_dirty(BlockDriverState *bs)
 {
     BDRVQcowState *s = bs->opaque;
     uint64_t val;
@@ -745,21 +745,6 @@ fail:
     return ret;
 }
 
-static void run_dependent_requests(BDRVQcowState *s, QCowL2Meta *m)
-{
-    /* Take the request off the list of running requests */
-    if (m->nb_clusters != 0) {
-        QLIST_REMOVE(m, next_in_flight);
-    }
-
-    /* Restart all dependent requests */
-    if (!qemu_co_queue_empty(&m->dependent_requests)) {
-        qemu_co_mutex_unlock(&s->lock);
-        qemu_co_queue_restart_all(&m->dependent_requests);
-        qemu_co_mutex_lock(&s->lock);
-    }
-}
-
 static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
                            int64_t sector_num,
                            int remaining_sectors,
@@ -774,15 +759,11 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
     QEMUIOVector hd_qiov;
     uint64_t bytes_done = 0;
     uint8_t *cluster_data = NULL;
-    QCowL2Meta l2meta = {
-        .nb_clusters = 0,
-    };
+    QCowL2Meta *l2meta;
 
     trace_qcow2_writev_start_req(qemu_coroutine_self(), sector_num,
                                  remaining_sectors);
 
-    qemu_co_queue_init(&l2meta.dependent_requests);
-
     qemu_iovec_init(&hd_qiov, qiov->niov);
 
     s->cluster_cache_offset = -1; /* disable compressed cache */
@@ -791,6 +772,8 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
 
     while (remaining_sectors != 0) {
 
+        l2meta = NULL;
+
         trace_qcow2_writev_start_part(qemu_coroutine_self());
         index_in_cluster = sector_num & (s->cluster_sectors - 1);
         n_end = index_in_cluster + remaining_sectors;
@@ -800,17 +783,11 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
         }
 
         ret = qcow2_alloc_cluster_offset(bs, sector_num << 9,
-            index_in_cluster, n_end, &cur_nr_sectors, &l2meta);
+            index_in_cluster, n_end, &cur_nr_sectors, &cluster_offset, &l2meta);
         if (ret < 0) {
             goto fail;
         }
 
-        if (l2meta.nb_clusters > 0 &&
-            (s->compatible_features & QCOW2_COMPAT_LAZY_REFCOUNTS)) {
-            qcow2_mark_dirty(bs);
-        }
-
-        cluster_offset = l2meta.cluster_offset;
         assert((cluster_offset & 511) == 0);
 
         qemu_iovec_reset(&hd_qiov);
@@ -835,8 +812,8 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
                 cur_nr_sectors * 512);
         }
 
-        BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
         qemu_co_mutex_unlock(&s->lock);
+        BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
         trace_qcow2_writev_data(qemu_coroutine_self(),
                                 (cluster_offset >> 9) + index_in_cluster);
         ret = bdrv_co_writev(bs->file,
@@ -847,12 +824,24 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
             goto fail;
         }
 
-        ret = qcow2_alloc_cluster_link_l2(bs, &l2meta);
-        if (ret < 0) {
-            goto fail;
-        }
+        if (l2meta != NULL) {
+            ret = qcow2_alloc_cluster_link_l2(bs, l2meta);
+            if (ret < 0) {
+                goto fail;
+            }
+
+            /* Take the request off the list of running requests */
+            if (l2meta->nb_clusters != 0) {
+                QLIST_REMOVE(l2meta, next_in_flight);
+            }
+
+            qemu_co_mutex_unlock(&s->lock);
+            qemu_co_queue_restart_all(&l2meta->dependent_requests);
+            qemu_co_mutex_lock(&s->lock);
 
-        run_dependent_requests(s, &l2meta);
+            g_free(l2meta);
+            l2meta = NULL;
+        }
 
         remaining_sectors -= cur_nr_sectors;
         sector_num += cur_nr_sectors;
@@ -862,10 +851,16 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
     ret = 0;
 
 fail:
-    run_dependent_requests(s, &l2meta);
-
     qemu_co_mutex_unlock(&s->lock);
 
+    if (l2meta != NULL) {
+        if (l2meta->nb_clusters != 0) {
+            QLIST_REMOVE(l2meta, next_in_flight);
+        }
+        qemu_co_queue_restart_all(&l2meta->dependent_requests);
+        g_free(l2meta);
+    }
+
     qemu_iovec_destroy(&hd_qiov);
     qemu_vfree(cluster_data);
     trace_qcow2_writev_done_req(qemu_coroutine_self(), ret);
@@ -1128,31 +1123,33 @@ static int preallocate(BlockDriverState *bs)
 {
     uint64_t nb_sectors;
     uint64_t offset;
+    uint64_t host_offset = 0;
     int num;
     int ret;
-    QCowL2Meta meta;
+    QCowL2Meta *meta;
 
     nb_sectors = bdrv_getlength(bs) >> 9;
     offset = 0;
-    qemu_co_queue_init(&meta.dependent_requests);
-    meta.cluster_offset = 0;
 
     while (nb_sectors) {
         num = MIN(nb_sectors, INT_MAX >> 9);
-        ret = qcow2_alloc_cluster_offset(bs, offset, 0, num, &num, &meta);
+        ret = qcow2_alloc_cluster_offset(bs, offset, 0, num, &num,
+                                         &host_offset, &meta);
         if (ret < 0) {
             return ret;
         }
 
-        ret = qcow2_alloc_cluster_link_l2(bs, &meta);
+        ret = qcow2_alloc_cluster_link_l2(bs, meta);
         if (ret < 0) {
-            qcow2_free_any_clusters(bs, meta.cluster_offset, meta.nb_clusters);
+            qcow2_free_any_clusters(bs, meta->alloc_offset, meta->nb_clusters);
             return ret;
         }
 
         /* There are no dependent requests, but we need to remove our request
          * from the list of in-flight requests */
-        run_dependent_requests(bs->opaque, &meta);
+        if (meta != NULL) {
+            QLIST_REMOVE(meta, next_in_flight);
+        }
 
         /* TODO Preallocate data if requested */
 
@@ -1165,10 +1162,10 @@ static int preallocate(BlockDriverState *bs)
      * all of the allocated clusters (otherwise we get failing reads after
      * EOF). Extend the image to the last allocated sector.
      */
-    if (meta.cluster_offset != 0) {
+    if (host_offset != 0) {
         uint8_t buf[512];
         memset(buf, 0, 512);
-        ret = bdrv_write(bs->file, (meta.cluster_offset >> 9) + num - 1, buf, 1);
+        ret = bdrv_write(bs->file, (host_offset >> 9) + num - 1, buf, 1);
         if (ret < 0) {
             return ret;
         }
diff --git a/block/qcow2.h b/block/qcow2.h
index b4eb654..a60fcb4 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -196,17 +196,56 @@ typedef struct QCowCreateState {
 
 struct QCowAIOCB;
 
-/* XXX This could be private for qcow2-cluster.c */
+typedef struct Qcow2COWRegion {
+    /**
+     * Offset of the COW region in bytes from the start of the first cluster
+     * touched by the request.
+     */
+    uint64_t    offset;
+
+    /** Number of sectors to copy */
+    int         nb_sectors;
+} Qcow2COWRegion;
+
+/**
+ * Describes an in-flight (part of a) write request that writes to clusters
+ * that are not referenced in their L2 table yet.
+ */
 typedef struct QCowL2Meta
 {
+    /** Guest offset of the first newly allocated cluster */
     uint64_t offset;
-    uint64_t cluster_offset;
+
+    /** Host offset of the first newly allocated cluster */
     uint64_t alloc_offset;
-    int n_start;
+
+    /**
+     * Number of sectors from the start of the first allocated cluster to
+     * the end of the (possibly shortened) request
+     */
     int nb_available;
+
+    /** Number of newly allocated clusters */
     int nb_clusters;
+
+    /**
+     * Requests that overlap with this allocation and wait to be restarted
+     * when the allocating request has completed.
+     */
     CoQueue dependent_requests;
 
+    /**
+     * The COW Region between the start of the first allocated cluster and the
+     * area the guest actually writes to.
+     */
+    Qcow2COWRegion cow_start;
+
+    /**
+     * The COW Region between the area the guest actually writes to and the
+     * end of the last allocated cluster.
+     */
+    Qcow2COWRegion cow_end;
+
     QLIST_ENTRY(QCowL2Meta) next_in_flight;
 } QCowL2Meta;
 
@@ -264,6 +303,8 @@ static inline bool qcow2_need_accurate_refcounts(BDRVQcowState *s)
 /* qcow2.c functions */
 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
                   int64_t sector_num, int nb_sectors);
+
+int qcow2_mark_dirty(BlockDriverState *bs);
 int qcow2_update_header(BlockDriverState *bs);
 
 /* qcow2-refcount.c functions */
@@ -297,7 +338,7 @@ void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
     int *num, uint64_t *cluster_offset);
 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
-    int n_start, int n_end, int *num, QCowL2Meta *m);
+    int n_start, int n_end, int *num, uint64_t *host_offset, QCowL2Meta **m);
 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
                                          uint64_t offset,
                                          int compressed_size);
diff --git a/block/raw-posix.c b/block/raw-posix.c
index 550c81f..abfedbe 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -708,22 +708,6 @@ static BlockDriverAIOCB *paio_submit(BlockDriverState *bs, int fd,
     return thread_pool_submit_aio(aio_worker, acb, cb, opaque);
 }
 
-static BlockDriverAIOCB *paio_ioctl(BlockDriverState *bs, int fd,
-        unsigned long int req, void *buf,
-        BlockDriverCompletionFunc *cb, void *opaque)
-{
-    RawPosixAIOData *acb = g_slice_new(RawPosixAIOData);
-
-    acb->bs = bs;
-    acb->aio_type = QEMU_AIO_IOCTL;
-    acb->aio_fildes = fd;
-    acb->aio_offset = 0;
-    acb->aio_ioctl_buf = buf;
-    acb->aio_ioctl_cmd = req;
-
-    return thread_pool_submit_aio(aio_worker, acb, cb, opaque);
-}
-
 static BlockDriverAIOCB *raw_aio_submit(BlockDriverState *bs,
         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
         BlockDriverCompletionFunc *cb, void *opaque, int type)
@@ -1346,10 +1330,19 @@ static BlockDriverAIOCB *hdev_aio_ioctl(BlockDriverState *bs,
         BlockDriverCompletionFunc *cb, void *opaque)
 {
     BDRVRawState *s = bs->opaque;
+    RawPosixAIOData *acb;
 
     if (fd_open(bs) < 0)
         return NULL;
-    return paio_ioctl(bs, s->fd, req, buf, cb, opaque);
+
+    acb = g_slice_new(RawPosixAIOData);
+    acb->bs = bs;
+    acb->aio_type = QEMU_AIO_IOCTL;
+    acb->aio_fildes = s->fd;
+    acb->aio_offset = 0;
+    acb->aio_ioctl_buf = buf;
+    acb->aio_ioctl_cmd = req;
+    return thread_pool_submit_aio(aio_worker, acb, cb, opaque);
 }
 
 #elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
diff --git a/block/raw-win32.c b/block/raw-win32.c
index 0c05c58..ce207a3 100644
--- a/block/raw-win32.c
+++ b/block/raw-win32.c
@@ -303,13 +303,24 @@ static int raw_truncate(BlockDriverState *bs, int64_t offset)
 {
     BDRVRawState *s = bs->opaque;
     LONG low, high;
+    DWORD dwPtrLow;
 
     low = offset;
     high = offset >> 32;
-    if (!SetFilePointer(s->hfile, low, &high, FILE_BEGIN))
-	return -EIO;
-    if (!SetEndOfFile(s->hfile))
+
+    /*
+     * An error has occurred if the return value is INVALID_SET_FILE_POINTER
+     * and GetLastError doesn't return NO_ERROR.
+     */
+    dwPtrLow = SetFilePointer(s->hfile, low, &high, FILE_BEGIN);
+    if (dwPtrLow == INVALID_SET_FILE_POINTER && GetLastError() != NO_ERROR) {
+        fprintf(stderr, "SetFilePointer error: %d\n", GetLastError());
+        return -EIO;
+    }
+    if (SetEndOfFile(s->hfile) == 0) {
+        fprintf(stderr, "SetEndOfFile error: %d\n", GetLastError());
         return -EIO;
+    }
     return 0;
 }
 
diff --git a/block/rbd.c b/block/rbd.c
index f3becc7..737bab1 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -77,6 +77,7 @@ typedef struct RBDAIOCB {
     int error;
     struct BDRVRBDState *s;
     int cancelled;
+    int status;
 } RBDAIOCB;
 
 typedef struct RADOSCB {
@@ -376,12 +377,6 @@ static void qemu_rbd_complete_aio(RADOSCB *rcb)
     RBDAIOCB *acb = rcb->acb;
     int64_t r;
 
-    if (acb->cancelled) {
-        qemu_vfree(acb->bounce);
-        qemu_aio_release(acb);
-        goto done;
-    }
-
     r = rcb->ret;
 
     if (acb->cmd == RBD_AIO_WRITE ||
@@ -409,7 +404,6 @@ static void qemu_rbd_complete_aio(RADOSCB *rcb)
     /* Note that acb->bh can be NULL in case where the aio was cancelled */
     acb->bh = qemu_bh_new(rbd_aio_bh_cb, acb);
     qemu_bh_schedule(acb->bh);
-done:
     g_free(rcb);
 }
 
@@ -568,6 +562,12 @@ static void qemu_rbd_aio_cancel(BlockDriverAIOCB *blockacb)
 {
     RBDAIOCB *acb = (RBDAIOCB *) blockacb;
     acb->cancelled = 1;
+
+    while (acb->status == -EINPROGRESS) {
+        qemu_aio_wait();
+    }
+
+    qemu_aio_release(acb);
 }
 
 static const AIOCBInfo rbd_aiocb_info = {
@@ -639,8 +639,11 @@ static void rbd_aio_bh_cb(void *opaque)
     acb->common.cb(acb->common.opaque, (acb->ret > 0 ? 0 : acb->ret));
     qemu_bh_delete(acb->bh);
     acb->bh = NULL;
+    acb->status = 0;
 
-    qemu_aio_release(acb);
+    if (!acb->cancelled) {
+        qemu_aio_release(acb);
+    }
 }
 
 static int rbd_aio_discard_wrapper(rbd_image_t image,
@@ -685,6 +688,7 @@ static BlockDriverAIOCB *rbd_start_aio(BlockDriverState *bs,
     acb->s = s;
     acb->cancelled = 0;
     acb->bh = NULL;
+    acb->status = -EINPROGRESS;
 
     if (cmd == RBD_AIO_WRITE) {
         qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size);
diff --git a/block/stream.c b/block/stream.c
index 0c0fc7a..0dcd286 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -108,7 +108,7 @@ static void coroutine_fn stream_run(void *opaque)
 
 wait:
         /* Note that even when no rate limit is applied we need to yield
-         * with no pending I/O here so that qemu_aio_flush() returns.
+         * with no pending I/O here so that bdrv_drain_all() returns.
          */
         block_job_sleep_ns(&s->common, rt_clock, delay_ns);
         if (block_job_is_cancelled(&s->common)) {
diff --git a/block/vpc.c b/block/vpc.c
index b6bf52f..566e9a3 100644
--- a/block/vpc.c
+++ b/block/vpc.c
@@ -26,6 +26,9 @@
 #include "block_int.h"
 #include "module.h"
 #include "migration.h"
+#if defined(CONFIG_UUID)
+#include <uuid/uuid.h>
+#endif
 
 /**************************************************************/
 
@@ -198,7 +201,8 @@ static int vpc_open(BlockDriverState *bs, int flags)
     bs->total_sectors = (int64_t)
         be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl;
 
-    if (bs->total_sectors >= 65535 * 16 * 255) {
+    /* Allow a maximum disk size of approximately 2 TB */
+    if (bs->total_sectors >= 65535LL * 255 * 255) {
         err = -EFBIG;
         goto fail;
     }
@@ -524,19 +528,27 @@ static coroutine_fn int vpc_co_write(BlockDriverState *bs, int64_t sector_num,
  * Note that the geometry doesn't always exactly match total_sectors but
  * may round it down.
  *
- * Returns 0 on success, -EFBIG if the size is larger than 127 GB
+ * Returns 0 on success, -EFBIG if the size is larger than ~2 TB. Override
+ * the hardware EIDE and ATA-2 limit of 16 heads (max disk size of 127 GB)
+ * and instead allow up to 255 heads.
  */
 static int calculate_geometry(int64_t total_sectors, uint16_t* cyls,
     uint8_t* heads, uint8_t* secs_per_cyl)
 {
     uint32_t cyls_times_heads;
 
-    if (total_sectors > 65535 * 16 * 255)
+    /* Allow a maximum disk size of approximately 2 TB */
+    if (total_sectors > 65535LL * 255 * 255) {
         return -EFBIG;
+    }
 
     if (total_sectors > 65535 * 16 * 63) {
         *secs_per_cyl = 255;
-        *heads = 16;
+        if (total_sectors > 65535 * 16 * 255) {
+            *heads = 255;
+        } else {
+            *heads = 16;
+        }
         cyls_times_heads = total_sectors / *secs_per_cyl;
     } else {
         *secs_per_cyl = 17;
@@ -739,7 +751,9 @@ static int vpc_create(const char *filename, QEMUOptionParameter *options)
 
     footer->type = be32_to_cpu(disk_type);
 
-    /* TODO uuid is missing */
+#if defined(CONFIG_UUID)
+    uuid_generate(footer->uuid);
+#endif
 
     footer->checksum = be32_to_cpu(vpc_checksum(buf, HEADER_SIZE));
 
diff --git a/block_int.h b/block_int.h
index 9deedb8..bf3f79b 100644
--- a/block_int.h
+++ b/block_int.h
@@ -190,6 +190,12 @@ struct BlockDriver {
 
     void (*bdrv_debug_event)(BlockDriverState *bs, BlkDebugEvent event);
 
+    /* TODO Better pass a option string/QDict/QemuOpts to add any rule? */
+    int (*bdrv_debug_breakpoint)(BlockDriverState *bs, const char *event,
+        const char *tag);
+    int (*bdrv_debug_resume)(BlockDriverState *bs, const char *tag);
+    bool (*bdrv_debug_is_suspended)(BlockDriverState *bs, const char *tag);
+
     /*
      * Returns 1 if newly created images are guaranteed to contain only
      * zeros, 0 otherwise.
diff --git a/blockdev.c b/blockdev.c
index e73fd6e..9a05e57 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -275,7 +275,7 @@ static bool do_check_io_limits(BlockIOLimit *io_limits)
     return true;
 }
 
-DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
+DriveInfo *drive_init(QemuOpts *opts, BlockInterfaceType block_default_type)
 {
     const char *buf;
     const char *file = NULL;
@@ -325,7 +325,7 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
             return NULL;
 	}
     } else {
-        type = default_to_scsi ? IF_SCSI : IF_IDE;
+        type = block_default_type;
     }
 
     max_devs = if_max_devs[type];
@@ -568,7 +568,7 @@ DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
         break;
     case IF_VIRTIO:
         /* add virtio block device */
-        opts = qemu_opts_create(qemu_find_opts("device"), NULL, 0, NULL);
+        opts = qemu_opts_create_nofail(qemu_find_opts("device"));
         if (arch_type == QEMU_ARCH_S390X) {
             qemu_opt_set(opts, "driver", "virtio-blk-s390");
         } else {
@@ -707,6 +707,7 @@ void qmp_transaction(BlockdevActionList *dev_list, Error **errp)
     int ret = 0;
     BlockdevActionList *dev_entry = dev_list;
     BlkTransactionStates *states, *next;
+    Error *local_err = NULL;
 
     QSIMPLEQ_HEAD(snap_bdrv_states, BlkTransactionStates) snap_bdrv_states;
     QSIMPLEQ_INIT(&snap_bdrv_states);
@@ -786,12 +787,12 @@ void qmp_transaction(BlockdevActionList *dev_list, Error **errp)
 
         /* create new image w/backing file */
         if (mode != NEW_IMAGE_MODE_EXISTING) {
-            ret = bdrv_img_create(new_image_file, format,
-                                  states->old_bs->filename,
-                                  states->old_bs->drv->format_name,
-                                  NULL, -1, flags);
-            if (ret) {
-                error_set(errp, QERR_OPEN_FILE_FAILED, new_image_file);
+            bdrv_img_create(new_image_file, format,
+                            states->old_bs->filename,
+                            states->old_bs->drv->format_name,
+                            NULL, -1, flags, &local_err);
+            if (error_is_set(&local_err)) {
+                error_propagate(errp, local_err);
                 goto delete_and_fail;
             }
         }
@@ -1263,8 +1264,8 @@ void qmp_drive_mirror(const char *device, const char *target,
         assert(format && drv);
         bdrv_get_geometry(bs, &size);
         size *= 512;
-        ret = bdrv_img_create(target, format,
-                              NULL, NULL, NULL, size, flags);
+        bdrv_img_create(target, format,
+                        NULL, NULL, NULL, size, flags, &local_err);
     } else {
         switch (mode) {
         case NEW_IMAGE_MODE_EXISTING:
@@ -1272,18 +1273,18 @@ void qmp_drive_mirror(const char *device, const char *target,
             break;
         case NEW_IMAGE_MODE_ABSOLUTE_PATHS:
             /* create new image with backing file */
-            ret = bdrv_img_create(target, format,
-                                  source->filename,
-                                  source->drv->format_name,
-                                  NULL, -1, flags);
+            bdrv_img_create(target, format,
+                            source->filename,
+                            source->drv->format_name,
+                            NULL, -1, flags, &local_err);
             break;
         default:
             abort();
         }
     }
 
-    if (ret) {
-        error_set(errp, QERR_OPEN_FILE_FAILED, target);
+    if (error_is_set(&local_err)) {
+        error_propagate(errp, local_err);
         return;
     }
 
diff --git a/blockdev.h b/blockdev.h
index 5f27b64..d73d552 100644
--- a/blockdev.h
+++ b/blockdev.h
@@ -19,8 +19,13 @@ void blockdev_auto_del(BlockDriverState *bs);
 
 typedef enum {
     IF_DEFAULT = -1,            /* for use with drive_add() only */
+    /*
+     * IF_IDE must be zero, because we want QEMUMachine member
+     * block_default_type to default-initialize to IF_IDE
+     */
+    IF_IDE = 0,
     IF_NONE,
-    IF_IDE, IF_SCSI, IF_FLOPPY, IF_PFLASH, IF_MTD, IF_SD, IF_VIRTIO, IF_XEN,
+    IF_SCSI, IF_FLOPPY, IF_PFLASH, IF_MTD, IF_SD, IF_VIRTIO, IF_XEN,
     IF_COUNT
 } BlockInterfaceType;
 
@@ -51,7 +56,7 @@ DriveInfo *drive_get_by_blockdev(BlockDriverState *bs);
 QemuOpts *drive_def(const char *optstr);
 QemuOpts *drive_add(BlockInterfaceType type, int index, const char *file,
                     const char *optstr);
-DriveInfo *drive_init(QemuOpts *arg, int default_to_scsi);
+DriveInfo *drive_init(QemuOpts *arg, BlockInterfaceType block_default_type);
 
 /* device-hotplug */
 
diff --git a/hw/boards.h b/hw/boards.h
index 813d0e5..c66fa16 100644
--- a/hw/boards.h
+++ b/hw/boards.h
@@ -3,6 +3,7 @@
 #ifndef HW_BOARDS_H
 #define HW_BOARDS_H
 
+#include "blockdev.h"
 #include "qdev.h"
 
 typedef struct QEMUMachineInitArgs {
@@ -24,7 +25,7 @@ typedef struct QEMUMachine {
     const char *desc;
     QEMUMachineInitFunc *init;
     QEMUMachineResetFunc *reset;
-    int use_scsi;
+    BlockInterfaceType block_default_type;
     int max_cpus;
     unsigned int no_serial:1,
         no_parallel:1,
diff --git a/hw/device-hotplug.c b/hw/device-hotplug.c
index 6d9c080..839b9ea 100644
--- a/hw/device-hotplug.c
+++ b/hw/device-hotplug.c
@@ -39,7 +39,7 @@ DriveInfo *add_init_drive(const char *optstr)
     if (!opts)
         return NULL;
 
-    dinfo = drive_init(opts, current_machine->use_scsi);
+    dinfo = drive_init(opts, current_machine->block_default_type);
     if (!dinfo) {
         qemu_opts_del(opts);
         return NULL;
diff --git a/hw/highbank.c b/hw/highbank.c
index 447e57d..8e35127 100644
--- a/hw/highbank.c
+++ b/hw/highbank.c
@@ -329,7 +329,7 @@ static QEMUMachine highbank_machine = {
     .name = "highbank",
     .desc = "Calxeda Highbank (ECX-1000)",
     .init = highbank_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
     .max_cpus = 4,
 };
 
diff --git a/hw/ide/core.c b/hw/ide/core.c
index c4f93d0..1235612 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -1869,6 +1869,8 @@ static void ide_reset(IDEState *s)
     s->io_buffer_index = 0;
     s->cd_sector_size = 0;
     s->atapi_dma = 0;
+    s->tray_locked = 0;
+    s->tray_open = 0;
     /* ATA DMA state */
     s->io_buffer_size = 0;
     s->req_nb_sectors = 0;
diff --git a/hw/leon3.c b/hw/leon3.c
index 7742738..ef83dff 100644
--- a/hw/leon3.c
+++ b/hw/leon3.c
@@ -212,7 +212,6 @@ static QEMUMachine leon3_generic_machine = {
     .name     = "leon3_generic",
     .desc     = "Leon-3 generic",
     .init     = leon3_generic_hw_init,
-    .use_scsi = 0,
 };
 
 static void leon3_machine_init(void)
diff --git a/hw/mips_jazz.c b/hw/mips_jazz.c
index 0847427..ea1416a 100644
--- a/hw/mips_jazz.c
+++ b/hw/mips_jazz.c
@@ -324,14 +324,14 @@ static QEMUMachine mips_magnum_machine = {
     .name = "magnum",
     .desc = "MIPS Magnum",
     .init = mips_magnum_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
 };
 
 static QEMUMachine mips_pica61_machine = {
     .name = "pica61",
     .desc = "Acer Pica 61",
     .init = mips_pica61_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
 };
 
 static void mips_jazz_machine_init(void)
diff --git a/hw/pc_sysfw.c b/hw/pc_sysfw.c
index 40bced2..d7ea3a5 100644
--- a/hw/pc_sysfw.c
+++ b/hw/pc_sysfw.c
@@ -98,7 +98,7 @@ static void pc_fw_add_pflash_drv(void)
       return;
     }
 
-    if (!drive_init(opts, machine->use_scsi)) {
+    if (!drive_init(opts, machine->block_default_type)) {
         qemu_opts_del(opts);
     }
 }
diff --git a/hw/puv3.c b/hw/puv3.c
index 764799c..3d77349 100644
--- a/hw/puv3.c
+++ b/hw/puv3.c
@@ -122,7 +122,6 @@ static QEMUMachine puv3_machine = {
     .desc = "PKUnity Version-3 based on UniCore32",
     .init = puv3_init,
     .is_default = 1,
-    .use_scsi = 0,
 };
 
 static void puv3_machine_init(void)
diff --git a/hw/realview.c b/hw/realview.c
index e789c15..8ea4ad7 100644
--- a/hw/realview.c
+++ b/hw/realview.c
@@ -364,14 +364,14 @@ static QEMUMachine realview_eb_machine = {
     .name = "realview-eb",
     .desc = "ARM RealView Emulation Baseboard (ARM926EJ-S)",
     .init = realview_eb_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
 };
 
 static QEMUMachine realview_eb_mpcore_machine = {
     .name = "realview-eb-mpcore",
     .desc = "ARM RealView Emulation Baseboard (ARM11MPCore)",
     .init = realview_eb_mpcore_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
     .max_cpus = 4,
 };
 
@@ -385,7 +385,7 @@ static QEMUMachine realview_pbx_a9_machine = {
     .name = "realview-pbx-a9",
     .desc = "ARM RealView Platform Baseboard Explore for Cortex-A9",
     .init = realview_pbx_a9_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
     .max_cpus = 4,
 };
 
diff --git a/hw/s390-virtio.c b/hw/s390-virtio.c
index ca1bb09..7aca0c4 100644
--- a/hw/s390-virtio.c
+++ b/hw/s390-virtio.c
@@ -314,21 +314,6 @@ static void s390_init(QEMUMachineInitArgs *args)
         qdev_set_nic_properties(dev, nd);
         qdev_init_nofail(dev);
     }
-
-    /* Create VirtIO disk drives */
-    for(i = 0; i < MAX_BLK_DEVS; i++) {
-        DriveInfo *dinfo;
-        DeviceState *dev;
-
-        dinfo = drive_get(IF_IDE, 0, i);
-        if (!dinfo) {
-            continue;
-        }
-
-        dev = qdev_create((BusState *)s390_bus, "virtio-blk-s390");
-        qdev_prop_set_drive_nofail(dev, "drive", dinfo->bdrv);
-        qdev_init_nofail(dev);
-    }
 }
 
 static QEMUMachine s390_machine = {
@@ -336,6 +321,7 @@ static QEMUMachine s390_machine = {
     .alias = "s390",
     .desc = "VirtIO based S390 machine",
     .init = s390_init,
+    .block_default_type = IF_VIRTIO,
     .no_cdrom = 1,
     .no_floppy = 1,
     .no_serial = 1,
@@ -352,3 +338,4 @@ static void s390_machine_init(void)
 }
 
 machine_init(s390_machine_init);
+
diff --git a/hw/spapr.c b/hw/spapr.c
index ad3f0ea..d955f02 100644
--- a/hw/spapr.c
+++ b/hw/spapr.c
@@ -924,9 +924,9 @@ static QEMUMachine spapr_machine = {
     .desc = "pSeries Logical Partition (PAPR compliant)",
     .init = ppc_spapr_init,
     .reset = ppc_spapr_reset,
+    .block_default_type = IF_SCSI,
     .max_cpus = MAX_CPUS,
     .no_parallel = 1,
-    .use_scsi = 1,
 };
 
 static void spapr_machine_init(void)
diff --git a/hw/sun4m.c b/hw/sun4m.c
index 1a78676..52cf82b 100644
--- a/hw/sun4m.c
+++ b/hw/sun4m.c
@@ -1426,7 +1426,7 @@ static QEMUMachine ss5_machine = {
     .name = "SS-5",
     .desc = "Sun4m platform, SPARCstation 5",
     .init = ss5_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
     .is_default = 1,
 };
 
@@ -1434,7 +1434,7 @@ static QEMUMachine ss10_machine = {
     .name = "SS-10",
     .desc = "Sun4m platform, SPARCstation 10",
     .init = ss10_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
     .max_cpus = 4,
 };
 
@@ -1442,7 +1442,7 @@ static QEMUMachine ss600mp_machine = {
     .name = "SS-600MP",
     .desc = "Sun4m platform, SPARCserver 600MP",
     .init = ss600mp_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
     .max_cpus = 4,
 };
 
@@ -1450,7 +1450,7 @@ static QEMUMachine ss20_machine = {
     .name = "SS-20",
     .desc = "Sun4m platform, SPARCstation 20",
     .init = ss20_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
     .max_cpus = 4,
 };
 
@@ -1458,35 +1458,35 @@ static QEMUMachine voyager_machine = {
     .name = "Voyager",
     .desc = "Sun4m platform, SPARCstation Voyager",
     .init = vger_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
 };
 
 static QEMUMachine ss_lx_machine = {
     .name = "LX",
     .desc = "Sun4m platform, SPARCstation LX",
     .init = ss_lx_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
 };
 
 static QEMUMachine ss4_machine = {
     .name = "SS-4",
     .desc = "Sun4m platform, SPARCstation 4",
     .init = ss4_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
 };
 
 static QEMUMachine scls_machine = {
     .name = "SPARCClassic",
     .desc = "Sun4m platform, SPARCClassic",
     .init = scls_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
 };
 
 static QEMUMachine sbook_machine = {
     .name = "SPARCbook",
     .desc = "Sun4m platform, SPARCbook",
     .init = sbook_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
 };
 
 static const struct sun4d_hwdef sun4d_hwdefs[] = {
@@ -1709,7 +1709,7 @@ static QEMUMachine ss1000_machine = {
     .name = "SS-1000",
     .desc = "Sun4d platform, SPARCserver 1000",
     .init = ss1000_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
     .max_cpus = 8,
 };
 
@@ -1717,7 +1717,7 @@ static QEMUMachine ss2000_machine = {
     .name = "SS-2000",
     .desc = "Sun4d platform, SPARCcenter 2000",
     .init = ss2000_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
     .max_cpus = 20,
 };
 
@@ -1896,7 +1896,7 @@ static QEMUMachine ss2_machine = {
     .name = "SS-2",
     .desc = "Sun4c platform, SPARCstation 2",
     .init = ss2_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
 };
 
 static void sun4m_register_types(void)
diff --git a/hw/versatilepb.c b/hw/versatilepb.c
index 25e652b..4892c1d 100644
--- a/hw/versatilepb.c
+++ b/hw/versatilepb.c
@@ -358,14 +358,14 @@ static QEMUMachine versatilepb_machine = {
     .name = "versatilepb",
     .desc = "ARM Versatile/PB (ARM926EJ-S)",
     .init = vpb_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
 };
 
 static QEMUMachine versatileab_machine = {
     .name = "versatileab",
     .desc = "ARM Versatile/AB (ARM926EJ-S)",
     .init = vab_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
 };
 
 static void versatile_machine_init(void)
diff --git a/hw/vexpress.c b/hw/vexpress.c
index d93f057..e89694c 100644
--- a/hw/vexpress.c
+++ b/hw/vexpress.c
@@ -477,7 +477,7 @@ static QEMUMachine vexpress_a9_machine = {
     .name = "vexpress-a9",
     .desc = "ARM Versatile Express for Cortex-A9",
     .init = vexpress_a9_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
     .max_cpus = 4,
 };
 
@@ -485,7 +485,7 @@ static QEMUMachine vexpress_a15_machine = {
     .name = "vexpress-a15",
     .desc = "ARM Versatile Express for Cortex-A15",
     .init = vexpress_a15_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
     .max_cpus = 4,
 };
 
diff --git a/hw/virtio-blk.h b/hw/virtio-blk.h
index f0740d0..651a000 100644
--- a/hw/virtio-blk.h
+++ b/hw/virtio-blk.h
@@ -104,7 +104,6 @@ struct VirtIOBlkConf
     BlockConf conf;
     char *serial;
     uint32_t scsi;
-    uint32_t config_wce;
 };
 
 #define DEFINE_VIRTIO_BLK_FEATURES(_state, _field) \
diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 71f4fb5..7684ac9 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -895,7 +895,6 @@ static Property virtio_blk_properties[] = {
 #ifdef __linux__
     DEFINE_PROP_BIT("scsi", VirtIOPCIProxy, blk.scsi, 0, true),
 #endif
-    DEFINE_PROP_BIT("config-wce", VirtIOPCIProxy, blk.config_wce, 0, true),
     DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags, VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
     DEFINE_VIRTIO_BLK_FEATURES(VirtIOPCIProxy, host_features),
diff --git a/hw/watchdog.c b/hw/watchdog.c
index b52aced..5c82c17 100644
--- a/hw/watchdog.c
+++ b/hw/watchdog.c
@@ -66,7 +66,7 @@ int select_watchdog(const char *p)
     QLIST_FOREACH(model, &watchdog_list, entry) {
         if (strcasecmp(model->wdt_name, p) == 0) {
             /* add the device */
-            opts = qemu_opts_create(qemu_find_opts("device"), NULL, 0, NULL);
+            opts = qemu_opts_create_nofail(qemu_find_opts("device"));
             qemu_opt_set(opts, "driver", p);
             return 0;
         }
diff --git a/hw/xilinx_zynq.c b/hw/xilinx_zynq.c
index 49233d8..9ca22a4 100644
--- a/hw/xilinx_zynq.c
+++ b/hw/xilinx_zynq.c
@@ -201,7 +201,7 @@ static QEMUMachine zynq_machine = {
     .name = "xilinx-zynq-a9",
     .desc = "Xilinx Zynq Platform Baseboard for Cortex-A9",
     .init = zynq_init,
-    .use_scsi = 1,
+    .block_default_type = IF_SCSI,
     .max_cpus = 1,
     .no_sdcard = 1
 };
diff --git a/main-loop.c b/main-loop.c
index c87624e..7dba6f6 100644
--- a/main-loop.c
+++ b/main-loop.c
@@ -432,11 +432,6 @@ QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque)
     return aio_bh_new(qemu_aio_context, cb, opaque);
 }
 
-void qemu_aio_flush(void)
-{
-    aio_flush(qemu_aio_context);
-}
-
 bool qemu_aio_wait(void)
 {
     return aio_poll(qemu_aio_context, true);
diff --git a/qemu-aio.h b/qemu-aio.h
index 3889fe9..31884a8 100644
--- a/qemu-aio.h
+++ b/qemu-aio.h
@@ -162,10 +162,6 @@ void qemu_bh_cancel(QEMUBH *bh);
  */
 void qemu_bh_delete(QEMUBH *bh);
 
-/* Flush any pending AIO operation. This function will block until all
- * outstanding AIO operations have been completed or cancelled. */
-void aio_flush(AioContext *ctx);
-
 /* Return whether there are any pending callbacks from the GSource
  * attached to the AioContext.
  *
@@ -196,7 +192,7 @@ typedef int (AioFlushHandler)(void *opaque);
 
 /* Register a file descriptor and associated callbacks.  Behaves very similarly
  * to qemu_set_fd_handler2.  Unlike qemu_set_fd_handler2, these callbacks will
- * be invoked when using either qemu_aio_wait() or qemu_aio_flush().
+ * be invoked when using qemu_aio_wait().
  *
  * Code that invokes AIO completion functions should rely on this function
  * instead of qemu_set_fd_handler[2].
@@ -211,7 +207,7 @@ void aio_set_fd_handler(AioContext *ctx,
 
 /* Register an event notifier and associated callbacks.  Behaves very similarly
  * to event_notifier_set_handler.  Unlike event_notifier_set_handler, these callbacks
- * will be invoked when using either qemu_aio_wait() or qemu_aio_flush().
+ * will be invoked when using qemu_aio_wait().
  *
  * Code that invokes AIO completion functions should rely on this function
  * instead of event_notifier_set_handler.
@@ -228,7 +224,6 @@ GSource *aio_get_g_source(AioContext *ctx);
 
 /* Functions to operate on the main QEMU AioContext.  */
 
-void qemu_aio_flush(void);
 bool qemu_aio_wait(void);
 void qemu_aio_set_event_notifier(EventNotifier *notifier,
                                  EventNotifierHandler *io_read,
diff --git a/qemu-config.c b/qemu-config.c
index aa78fb9..54db981 100644
--- a/qemu-config.c
+++ b/qemu-config.c
@@ -756,7 +756,7 @@ int qemu_global_option(const char *str)
         return -1;
     }
 
-    opts = qemu_opts_create(&qemu_global_opts, NULL, 0, NULL);
+    opts = qemu_opts_create_nofail(&qemu_global_opts);
     qemu_opt_set(opts, "driver", driver);
     qemu_opt_set(opts, "property", property);
     qemu_opt_set(opts, "value", str+offset+1);
@@ -843,7 +843,7 @@ int qemu_config_parse(FILE *fp, QemuOptsList **lists, const char *fname)
                 error_free(local_err);
                 goto out;
             }
-            opts = qemu_opts_create(list, NULL, 0, NULL);
+            opts = qemu_opts_create_nofail(list);
             continue;
         }
         if (sscanf(line, " %63s = \"%1023[^\"]\"", arg, value) == 2) {
diff --git a/qemu-img.c b/qemu-img.c
index e29e01b..c989a52 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -294,13 +294,14 @@ static int add_old_style_options(const char *fmt, QEMUOptionParameter *list,
 
 static int img_create(int argc, char **argv)
 {
-    int c, ret = 0;
+    int c;
     uint64_t img_size = -1;
     const char *fmt = "raw";
     const char *base_fmt = NULL;
     const char *filename;
     const char *base_filename = NULL;
     char *options = NULL;
+    Error *local_err = NULL;
 
     for(;;) {
         c = getopt(argc, argv, "F:b:f:he6o:");
@@ -350,23 +351,23 @@ static int img_create(int argc, char **argv)
             error_report("Invalid image size specified! You may use k, M, G or "
                   "T suffixes for ");
             error_report("kilobytes, megabytes, gigabytes and terabytes.");
-            ret = -1;
-            goto out;
+            return 1;
         }
         img_size = (uint64_t)sval;
     }
 
     if (options && is_help_option(options)) {
-        ret = print_block_option_help(filename, fmt);
-        goto out;
+        return print_block_option_help(filename, fmt);
     }
 
-    ret = bdrv_img_create(filename, fmt, base_filename, base_fmt,
-                          options, img_size, BDRV_O_FLAGS);
-out:
-    if (ret) {
+    bdrv_img_create(filename, fmt, base_filename, base_fmt,
+                    options, img_size, BDRV_O_FLAGS, &local_err);
+    if (error_is_set(&local_err)) {
+        error_report("%s", error_get_pretty(local_err));
+        error_free(local_err);
         return 1;
     }
+
     return 0;
 }
 
@@ -1933,7 +1934,7 @@ static int img_resize(int argc, char **argv)
     }
 
     /* Parse size */
-    param = qemu_opts_create(&resize_options, NULL, 0, NULL);
+    param = qemu_opts_create_nofail(&resize_options);
     if (qemu_opt_set(param, BLOCK_OPT_SIZE, size)) {
         /* Error message already printed when size parsing fails */
         ret = -1;
diff --git a/qemu-io.c b/qemu-io.c
index 92cdb2a..1637773 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -265,6 +265,18 @@ static int do_co_write_zeroes(int64_t offset, int count, int *total)
     }
 }
 
+static int do_write_compressed(char *buf, int64_t offset, int count, int *total)
+{
+    int ret;
+
+    ret = bdrv_write_compressed(bs, offset >> 9, (uint8_t *)buf, count >> 9);
+    if (ret < 0) {
+        return ret;
+    }
+    *total = count;
+    return 1;
+}
+
 static int do_load_vmstate(char *buf, int64_t offset, int count, int *total)
 {
     *total = bdrv_load_vmstate(bs, (uint8_t *)buf, offset, count);
@@ -687,6 +699,7 @@ static void write_help(void)
 " Writes into a segment of the currently open file, using a buffer\n"
 " filled with a set pattern (0xcdcdcdcd).\n"
 " -b, -- write to the VM state rather than the virtual disk\n"
+" -c, -- write compressed data with bdrv_write_compressed\n"
 " -p, -- use bdrv_pwrite to write the file\n"
 " -P, -- use different pattern to fill file\n"
 " -C, -- report statistics in a machine parsable format\n"
@@ -703,7 +716,7 @@ static const cmdinfo_t write_cmd = {
     .cfunc      = write_f,
     .argmin     = 2,
     .argmax     = -1,
-    .args       = "[-bCpqz] [-P pattern ] off len",
+    .args       = "[-bcCpqz] [-P pattern ] off len",
     .oneline    = "writes a number of bytes at a specified offset",
     .help       = write_help,
 };
@@ -712,6 +725,7 @@ static int write_f(int argc, char **argv)
 {
     struct timeval t1, t2;
     int Cflag = 0, pflag = 0, qflag = 0, bflag = 0, Pflag = 0, zflag = 0;
+    int cflag = 0;
     int c, cnt;
     char *buf = NULL;
     int64_t offset;
@@ -720,11 +734,14 @@ static int write_f(int argc, char **argv)
     int total = 0;
     int pattern = 0xcd;
 
-    while ((c = getopt(argc, argv, "bCpP:qz")) != EOF) {
+    while ((c = getopt(argc, argv, "bcCpP:qz")) != EOF) {
         switch (c) {
         case 'b':
             bflag = 1;
             break;
+        case 'c':
+            cflag = 1;
+            break;
         case 'C':
             Cflag = 1;
             break;
@@ -801,6 +818,8 @@ static int write_f(int argc, char **argv)
         cnt = do_save_vmstate(buf, offset, count, &total);
     } else if (zflag) {
         cnt = do_co_write_zeroes(offset, count, &total);
+    } else if (cflag) {
+        cnt = do_write_compressed(buf, offset, count, &total);
     } else {
         cnt = do_write(buf, offset, count, &total);
     }
@@ -1652,6 +1671,67 @@ static const cmdinfo_t map_cmd = {
        .oneline        = "prints the allocated areas of a file",
 };
 
+static int break_f(int argc, char **argv)
+{
+    int ret;
+
+    ret = bdrv_debug_breakpoint(bs, argv[1], argv[2]);
+    if (ret < 0) {
+        printf("Could not set breakpoint: %s\n", strerror(-ret));
+    }
+
+    return 0;
+}
+
+static const cmdinfo_t break_cmd = {
+       .name           = "break",
+       .argmin         = 2,
+       .argmax         = 2,
+       .cfunc          = break_f,
+       .args           = "event tag",
+       .oneline        = "sets a breakpoint on event and tags the stopped "
+                         "request as tag",
+};
+
+static int resume_f(int argc, char **argv)
+{
+    int ret;
+
+    ret = bdrv_debug_resume(bs, argv[1]);
+    if (ret < 0) {
+        printf("Could not resume request: %s\n", strerror(-ret));
+    }
+
+    return 0;
+}
+
+static const cmdinfo_t resume_cmd = {
+       .name           = "resume",
+       .argmin         = 1,
+       .argmax         = 1,
+       .cfunc          = resume_f,
+       .args           = "tag",
+       .oneline        = "resumes the request tagged as tag",
+};
+
+static int wait_break_f(int argc, char **argv)
+{
+    while (!bdrv_debug_is_suspended(bs, argv[1])) {
+        qemu_aio_wait();
+    }
+
+    return 0;
+}
+
+static const cmdinfo_t wait_break_cmd = {
+       .name           = "wait_break",
+       .argmin         = 1,
+       .argmax         = 1,
+       .cfunc          = wait_break_f,
+       .args           = "tag",
+       .oneline        = "waits for the suspension of a request",
+};
+
 static int abort_f(int argc, char **argv)
 {
     abort();
@@ -1915,6 +1995,9 @@ int main(int argc, char **argv)
     add_command(&discard_cmd);
     add_command(&alloc_cmd);
     add_command(&map_cmd);
+    add_command(&break_cmd);
+    add_command(&resume_cmd);
+    add_command(&wait_break_cmd);
     add_command(&abort_cmd);
 
     add_args_command(init_args_command);
diff --git a/qemu-option.c b/qemu-option.c
index 27891e7..94557cf 100644
--- a/qemu-option.c
+++ b/qemu-option.c
@@ -602,26 +602,36 @@ static void qemu_opt_del(QemuOpt *opt)
     g_free(opt);
 }
 
-static void opt_set(QemuOpts *opts, const char *name, const char *value,
-                    bool prepend, Error **errp)
+static bool opts_accepts_any(const QemuOpts *opts)
+{
+    return opts->list->desc[0].name == NULL;
+}
+
+static const QemuOptDesc *find_desc_by_name(const QemuOptDesc *desc,
+                                            const char *name)
 {
-    QemuOpt *opt;
-    const QemuOptDesc *desc = opts->list->desc;
-    Error *local_err = NULL;
     int i;
 
     for (i = 0; desc[i].name != NULL; i++) {
         if (strcmp(desc[i].name, name) == 0) {
-            break;
+            return &desc[i];
         }
     }
-    if (desc[i].name == NULL) {
-        if (i == 0) {
-            /* empty list -> allow any */;
-        } else {
-            error_set(errp, QERR_INVALID_PARAMETER, name);
-            return;
-        }
+
+    return NULL;
+}
+
+static void opt_set(QemuOpts *opts, const char *name, const char *value,
+                    bool prepend, Error **errp)
+{
+    QemuOpt *opt;
+    const QemuOptDesc *desc;
+    Error *local_err = NULL;
+
+    desc = find_desc_by_name(opts->list->desc, name);
+    if (!desc && !opts_accepts_any(opts)) {
+        error_set(errp, QERR_INVALID_PARAMETER, name);
+        return;
     }
 
     opt = g_malloc0(sizeof(*opt));
@@ -632,9 +642,7 @@ static void opt_set(QemuOpts *opts, const char *name, const char *value,
     } else {
         QTAILQ_INSERT_TAIL(&opts->head, opt, next);
     }
-    if (desc[i].name != NULL) {
-        opt->desc = desc+i;
-    }
+    opt->desc = desc;
     if (value) {
         opt->str = g_strdup(value);
     }
@@ -669,30 +677,43 @@ int qemu_opt_set_bool(QemuOpts *opts, const char *name, bool val)
 {
     QemuOpt *opt;
     const QemuOptDesc *desc = opts->list->desc;
-    int i;
 
-    for (i = 0; desc[i].name != NULL; i++) {
-        if (strcmp(desc[i].name, name) == 0) {
-            break;
-        }
-    }
-    if (desc[i].name == NULL) {
-        if (i == 0) {
-            /* empty list -> allow any */;
-        } else {
-            qerror_report(QERR_INVALID_PARAMETER, name);
-            return -1;
-        }
+    opt = g_malloc0(sizeof(*opt));
+    opt->desc = find_desc_by_name(desc, name);
+    if (!opt->desc && !opts_accepts_any(opts)) {
+        qerror_report(QERR_INVALID_PARAMETER, name);
+        g_free(opt);
+        return -1;
     }
 
-    opt = g_malloc0(sizeof(*opt));
     opt->name = g_strdup(name);
     opt->opts = opts;
+    opt->value.boolean = !!val;
+    opt->str = g_strdup(val ? "on" : "off");
     QTAILQ_INSERT_TAIL(&opts->head, opt, next);
-    if (desc[i].name != NULL) {
-        opt->desc = desc+i;
+
+    return 0;
+}
+
+int qemu_opt_set_number(QemuOpts *opts, const char *name, int64_t val)
+{
+    QemuOpt *opt;
+    const QemuOptDesc *desc = opts->list->desc;
+
+    opt = g_malloc0(sizeof(*opt));
+    opt->desc = find_desc_by_name(desc, name);
+    if (!opt->desc && !opts_accepts_any(opts)) {
+        qerror_report(QERR_INVALID_PARAMETER, name);
+        g_free(opt);
+        return -1;
     }
-    opt->value.boolean = !!val;
+
+    opt->name = g_strdup(name);
+    opt->opts = opts;
+    opt->value.uint = val;
+    opt->str = g_strdup_printf("%" PRId64, val);
+    QTAILQ_INSERT_TAIL(&opts->head, opt, next);
+
     return 0;
 }
 
@@ -781,6 +802,15 @@ QemuOpts *qemu_opts_create(QemuOptsList *list, const char *id,
     return opts;
 }
 
+QemuOpts *qemu_opts_create_nofail(QemuOptsList *list)
+{
+    QemuOpts *opts;
+    Error *errp = NULL;
+    opts = qemu_opts_create(list, NULL, 0, &errp);
+    assert_no_error(errp);
+    return opts;
+}
+
 void qemu_opts_reset(QemuOptsList *list)
 {
     QemuOpts *opts, *next_opts;
@@ -1068,23 +1098,15 @@ void qemu_opts_validate(QemuOpts *opts, const QemuOptDesc *desc, Error **errp)
     QemuOpt *opt;
     Error *local_err = NULL;
 
-    assert(opts->list->desc[0].name == NULL);
+    assert(opts_accepts_any(opts));
 
     QTAILQ_FOREACH(opt, &opts->head, next) {
-        int i;
-
-        for (i = 0; desc[i].name != NULL; i++) {
-            if (strcmp(desc[i].name, opt->name) == 0) {
-                break;
-            }
-        }
-        if (desc[i].name == NULL) {
+        opt->desc = find_desc_by_name(desc, opt->name);
+        if (!opt->desc) {
             error_set(errp, QERR_INVALID_PARAMETER, opt->name);
             return;
         }
 
-        opt->desc = &desc[i];
-
         qemu_opt_parse(opt, &local_err);
         if (error_is_set(&local_err)) {
             error_propagate(errp, local_err);
diff --git a/qemu-option.h b/qemu-option.h
index ca72986..002dd07 100644
--- a/qemu-option.h
+++ b/qemu-option.h
@@ -126,6 +126,7 @@ int qemu_opt_set(QemuOpts *opts, const char *name, const char *value);
 void qemu_opt_set_err(QemuOpts *opts, const char *name, const char *value,
                       Error **errp);
 int qemu_opt_set_bool(QemuOpts *opts, const char *name, bool val);
+int qemu_opt_set_number(QemuOpts *opts, const char *name, int64_t val);
 typedef int (*qemu_opt_loopfunc)(const char *name, const char *value, void *opaque);
 int qemu_opt_foreach(QemuOpts *opts, qemu_opt_loopfunc func, void *opaque,
                      int abort_on_failure);
@@ -133,6 +134,7 @@ int qemu_opt_foreach(QemuOpts *opts, qemu_opt_loopfunc func, void *opaque,
 QemuOpts *qemu_opts_find(QemuOptsList *list, const char *id);
 QemuOpts *qemu_opts_create(QemuOptsList *list, const char *id,
                            int fail_if_exists, Error **errp);
+QemuOpts *qemu_opts_create_nofail(QemuOptsList *list);
 void qemu_opts_reset(QemuOptsList *list);
 void qemu_opts_loc_restore(QemuOpts *opts);
 int qemu_opts_set(QemuOptsList *list, const char *id,
diff --git a/qemu-sockets.c b/qemu-sockets.c
index d314cf1..c52a40a 100644
--- a/qemu-sockets.c
+++ b/qemu-sockets.c
@@ -579,7 +579,7 @@ int inet_listen(const char *str, char *ostr, int olen,
 
     addr = inet_parse(str, errp);
     if (addr != NULL) {
-        opts = qemu_opts_create(&dummy_opts, NULL, 0, NULL);
+        opts = qemu_opts_create_nofail(&dummy_opts);
         inet_addr_to_opts(opts, addr);
         qapi_free_InetSocketAddress(addr);
         sock = inet_listen_opts(opts, port_offset, errp);
@@ -618,7 +618,7 @@ int inet_connect(const char *str, Error **errp)
 
     addr = inet_parse(str, errp);
     if (addr != NULL) {
-        opts = qemu_opts_create(&dummy_opts, NULL, 0, NULL);
+        opts = qemu_opts_create_nofail(&dummy_opts);
         inet_addr_to_opts(opts, addr);
         qapi_free_InetSocketAddress(addr);
         sock = inet_connect_opts(opts, errp, NULL, NULL);
@@ -652,7 +652,7 @@ int inet_nonblocking_connect(const char *str,
 
     addr = inet_parse(str, errp);
     if (addr != NULL) {
-        opts = qemu_opts_create(&dummy_opts, NULL, 0, NULL);
+        opts = qemu_opts_create_nofail(&dummy_opts);
         inet_addr_to_opts(opts, addr);
         qapi_free_InetSocketAddress(addr);
         sock = inet_connect_opts(opts, errp, callback, opaque);
@@ -795,7 +795,7 @@ int unix_listen(const char *str, char *ostr, int olen, Error **errp)
     char *path, *optstr;
     int sock, len;
 
-    opts = qemu_opts_create(&dummy_opts, NULL, 0, NULL);
+    opts = qemu_opts_create_nofail(&dummy_opts);
 
     optstr = strchr(str, ',');
     if (optstr) {
@@ -823,7 +823,7 @@ int unix_connect(const char *path, Error **errp)
     QemuOpts *opts;
     int sock;
 
-    opts = qemu_opts_create(&dummy_opts, NULL, 0, NULL);
+    opts = qemu_opts_create_nofail(&dummy_opts);
     qemu_opt_set(opts, "path", path);
     sock = unix_connect_opts(opts, errp, NULL, NULL);
     qemu_opts_del(opts);
@@ -840,7 +840,7 @@ int unix_nonblocking_connect(const char *path,
 
     g_assert(callback != NULL);
 
-    opts = qemu_opts_create(&dummy_opts, NULL, 0, NULL);
+    opts = qemu_opts_create_nofail(&dummy_opts);
     qemu_opt_set(opts, "path", path);
     sock = unix_connect_opts(opts, errp, callback, opaque);
     qemu_opts_del(opts);
@@ -891,7 +891,7 @@ int socket_connect(SocketAddress *addr, Error **errp,
     QemuOpts *opts;
     int fd;
 
-    opts = qemu_opts_create(&dummy_opts, NULL, 0, NULL);
+    opts = qemu_opts_create_nofail(&dummy_opts);
     switch (addr->kind) {
     case SOCKET_ADDRESS_KIND_INET:
         inet_addr_to_opts(opts, addr->inet);
@@ -922,7 +922,7 @@ int socket_listen(SocketAddress *addr, Error **errp)
     QemuOpts *opts;
     int fd;
 
-    opts = qemu_opts_create(&dummy_opts, NULL, 0, NULL);
+    opts = qemu_opts_create_nofail(&dummy_opts);
     switch (addr->kind) {
     case SOCKET_ADDRESS_KIND_INET:
         inet_addr_to_opts(opts, addr->inet);
diff --git a/tests/qemu-iotests/045 b/tests/qemu-iotests/045
new file mode 100755
index 0000000..2b6f1af
--- /dev/null
+++ b/tests/qemu-iotests/045
@@ -0,0 +1,129 @@
+#!/usr/bin/env python
+#
+# Tests for fdsets.
+#
+# Copyright (C) 2012 IBM Corp.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+import os
+import iotests
+from iotests import qemu_img
+
+image0 = os.path.join(iotests.test_dir, 'image0')
+image1 = os.path.join(iotests.test_dir, 'image1')
+image2 = os.path.join(iotests.test_dir, 'image2')
+image3 = os.path.join(iotests.test_dir, 'image3')
+image4 = os.path.join(iotests.test_dir, 'image4')
+
+class TestFdSets(iotests.QMPTestCase):
+
+    def setUp(self):
+        self.vm = iotests.VM()
+        qemu_img('create', '-f', iotests.imgfmt, image0, '128K')
+        qemu_img('create', '-f', iotests.imgfmt, image1, '128K')
+        qemu_img('create', '-f', iotests.imgfmt, image2, '128K')
+        qemu_img('create', '-f', iotests.imgfmt, image3, '128K')
+        qemu_img('create', '-f', iotests.imgfmt, image4, '128K')
+        self.file0 = open(image0, 'r')
+        self.file1 = open(image1, 'w+')
+        self.file2 = open(image2, 'r')
+        self.file3 = open(image3, 'r')
+        self.file4 = open(image4, 'r')
+        self.vm.add_fd(self.file0.fileno(), 1, 'image0:r')
+        self.vm.add_fd(self.file1.fileno(), 1, 'image1:w+')
+        self.vm.add_fd(self.file2.fileno(), 0, 'image2:r')
+        self.vm.add_fd(self.file3.fileno(), 2, 'image3:r')
+        self.vm.add_fd(self.file4.fileno(), 2, 'image4:r')
+        self.vm.add_drive("/dev/fdset/1")
+        self.vm.launch()
+
+    def tearDown(self):
+        self.vm.shutdown()
+        self.file0.close()
+        self.file1.close()
+        self.file2.close()
+        self.file3.close()
+        self.file4.close()
+        os.remove(image0)
+        os.remove(image1)
+        os.remove(image2)
+        os.remove(image3)
+        os.remove(image4)
+
+    def test_query_fdset(self):
+        result = self.vm.qmp('query-fdsets')
+        self.assert_qmp(result, 'return[0]/fdset-id', 2)
+        self.assert_qmp(result, 'return[1]/fdset-id', 1)
+        self.assert_qmp(result, 'return[2]/fdset-id', 0)
+        self.assert_qmp(result, 'return[0]/fds[0]/opaque', 'image3:r')
+        self.assert_qmp(result, 'return[0]/fds[1]/opaque', 'image4:r')
+        self.assert_qmp(result, 'return[1]/fds[0]/opaque', 'image0:r')
+        self.assert_qmp(result, 'return[1]/fds[1]/opaque', 'image1:w+')
+        self.assert_qmp(result, 'return[2]/fds[0]/opaque', 'image2:r')
+        self.vm.shutdown()
+
+    def test_remove_fdset(self):
+        result = self.vm.qmp('remove-fd', fdset_id=2)
+        self.assert_qmp(result, 'return', {})
+        result = self.vm.qmp('query-fdsets')
+        self.assert_qmp(result, 'return[0]/fdset-id', 1)
+        self.assert_qmp(result, 'return[1]/fdset-id', 0)
+        self.assert_qmp(result, 'return[0]/fds[0]/opaque', 'image0:r')
+        self.assert_qmp(result, 'return[0]/fds[1]/opaque', 'image1:w+')
+        self.assert_qmp(result, 'return[1]/fds[0]/opaque', 'image2:r')
+        self.vm.shutdown()
+
+    def test_remove_fd(self):
+        result = self.vm.qmp('query-fdsets')
+        fd_image3 = result['return'][0]['fds'][0]['fd']
+        result = self.vm.qmp('remove-fd', fdset_id=2, fd=fd_image3)
+        self.assert_qmp(result, 'return', {})
+        result = self.vm.qmp('query-fdsets')
+        self.assert_qmp(result, 'return[0]/fdset-id', 2)
+        self.assert_qmp(result, 'return[1]/fdset-id', 1)
+        self.assert_qmp(result, 'return[2]/fdset-id', 0)
+        self.assert_qmp(result, 'return[0]/fds[0]/opaque', 'image4:r')
+        self.assert_qmp(result, 'return[1]/fds[0]/opaque', 'image0:r')
+        self.assert_qmp(result, 'return[1]/fds[1]/opaque', 'image1:w+')
+        self.assert_qmp(result, 'return[2]/fds[0]/opaque', 'image2:r')
+        self.vm.shutdown()
+
+    def test_remove_fd_invalid_fdset(self):
+        result = self.vm.qmp('query-fdsets')
+        fd_image3 = result['return'][0]['fds'][0]['fd']
+        result = self.vm.qmp('remove-fd', fdset_id=3, fd=fd_image3)
+        self.assert_qmp(result, 'error/class', 'GenericError')
+        self.assert_qmp(result, 'error/desc',
+            'File descriptor named \'fdset-id:3, fd:%d\' not found' % fd_image3)
+        self.vm.shutdown()
+
+    def test_remove_fd_invalid_fd(self):
+        result = self.vm.qmp('query-fdsets')
+        result = self.vm.qmp('remove-fd', fdset_id=2, fd=999)
+        self.assert_qmp(result, 'error/class', 'GenericError')
+        self.assert_qmp(result, 'error/desc',
+            'File descriptor named \'fdset-id:2, fd:999\' not found')
+        self.vm.shutdown()
+
+    def test_add_fd_invalid_fd(self):
+        result = self.vm.qmp('add-fd', fdset_id=2)
+        self.assert_qmp(result, 'error/class', 'GenericError')
+        self.assert_qmp(result, 'error/desc',
+                'No file descriptor supplied via SCM_RIGHTS')
+        self.vm.shutdown()
+
+if __name__ == '__main__':
+    iotests.main(supported_fmts=['raw'])
diff --git a/tests/qemu-iotests/045.out b/tests/qemu-iotests/045.out
new file mode 100644
index 0000000..3f8a935
--- /dev/null
+++ b/tests/qemu-iotests/045.out
@@ -0,0 +1,5 @@
+......
+----------------------------------------------------------------------
+Ran 6 tests
+
+OK
diff --git a/tests/qemu-iotests/046 b/tests/qemu-iotests/046
new file mode 100755
index 0000000..e0176f4
--- /dev/null
+++ b/tests/qemu-iotests/046
@@ -0,0 +1,215 @@
+#!/bin/bash
+#
+# Test concurrent cluster allocations
+#
+# Copyright (C) 2012 Red Hat, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+# creator
+owner=kwolf@redhat.com
+
+seq=`basename $0`
+echo "QA output created by $seq"
+
+here=`pwd`
+tmp=/tmp/$$
+status=1	# failure is the default!
+
+_cleanup()
+{
+	_cleanup_test_img
+}
+trap "_cleanup; exit \$status" 0 1 2 3 15
+
+# get standard environment, filters and checks
+. ./common.rc
+. ./common.filter
+
+_supported_fmt qcow2
+_supported_proto generic
+_supported_os Linux
+
+CLUSTER_SIZE=64k
+size=128M
+
+echo
+echo "== creating backing file for COW tests =="
+
+_make_test_img $size
+
+function backing_io()
+{
+    local offset=$1
+    local sectors=$2
+    local op=$3
+    local pattern=0
+    local cur_sec=0
+
+    for i in $(seq 0 $((sectors - 1))); do
+        cur_sec=$((offset / 65536 + i))
+        pattern=$(( ( (cur_sec % 128) + (cur_sec / 128)) % 128 ))
+
+        echo "$op -P $pattern $((cur_sec * 64))k 64k"
+    done
+}
+
+backing_io 0 16 write | $QEMU_IO $TEST_IMG | _filter_qemu_io
+
+mv $TEST_IMG $TEST_IMG.base
+
+_make_test_img -b $TEST_IMG.base 6G
+
+echo
+echo "== Some concurrent requests touching the same cluster =="
+
+function overlay_io()
+{
+# Allocate middle of cluster 1, then write to somewhere before and after it
+cat  <<EOF
+break write_aio A
+aio_write -P 10 0x18000 0x2000
+wait_break A
+
+aio_write -P 11 0x12000 0x2000
+aio_write -P 12 0x1c000 0x2000
+
+resume A
+aio_flush
+EOF
+
+# Sequential write case: Alloc middle of cluster 2, then write overlapping
+# to next cluster
+cat  <<EOF
+break write_aio A
+aio_write -P 20 0x28000 0x2000
+wait_break A
+aio_write -P 21 0x2a000 0x10000
+resume A
+aio_flush
+EOF
+
+# The same with a gap between both requests
+cat  <<EOF
+break write_aio A
+aio_write -P 40 0x48000 0x2000
+wait_break A
+aio_write -P 41 0x4c000 0x10000
+resume A
+aio_flush
+EOF
+
+# Sequential write, but the next cluster is already allocated
+cat  <<EOF
+write -P 70 0x76000 0x8000
+aio_flush
+break write_aio A
+aio_write -P 60 0x66000 0x2000
+wait_break A
+aio_write -P 61 0x6a000 0xe000
+resume A
+aio_flush
+EOF
+
+# Sequential write, but the next cluster is already allocated
+# and phyiscally in the right position
+cat  <<EOF
+write -P 89 0x80000 0x1000
+write -P 90 0x96000 0x8000
+aio_flush
+discard 0x80000 0x10000
+aio_flush
+break write_aio A
+aio_write -P 80 0x86000 0x2000
+wait_break A
+aio_write -P 81 0x8a000 0xe000
+resume A
+aio_flush
+EOF
+
+# Sequential write, and the next cluster is compressed
+cat  <<EOF
+write    -P 109 0xa0000 0x1000
+write -c -P 110 0xb0000 0x10000
+aio_flush
+discard 0xa0000 0x10000
+aio_flush
+break write_aio A
+aio_write -P 100 0xa6000 0x2000
+wait_break A
+aio_write -P 101 0xaa000 0xe000
+resume A
+aio_flush
+EOF
+}
+
+overlay_io | $QEMU_IO blkdebug::$TEST_IMG | _filter_qemu_io |\
+	sed -e 's/bytes at offset [0-9]*/bytes at offset XXX/g'
+
+echo
+echo "== Verify image content =="
+
+function verify_io()
+{
+    echo read -P 0 0 0x10000
+
+    echo read -P 1  0x10000 0x2000
+    echo read -P 11 0x12000 0x2000
+    echo read -P 1  0x14000 0x4000
+    echo read -P 10 0x18000 0x2000
+    echo read -P 1  0x1a000 0x2000
+    echo read -P 12 0x1c000 0x2000
+    echo read -P 1  0x1e000 0x2000
+
+    echo read -P 2  0x20000 0x8000
+    echo read -P 20 0x28000 0x2000
+    echo read -P 21 0x2a000 0x10000
+    echo read -P 3  0x3a000 0x6000
+
+    echo read -P 4  0x40000 0x8000
+    echo read -P 40 0x48000 0x2000
+    echo read -P 4  0x4a000 0x2000
+    echo read -P 41 0x4c000 0x10000
+    echo read -P 5  0x5c000 0x4000
+
+    echo read -P 6  0x60000 0x6000
+    echo read -P 60 0x66000 0x2000
+    echo read -P 6  0x68000 0x2000
+    echo read -P 61 0x6a000 0xe000
+    echo read -P 70 0x78000 0x6000
+    echo read -P 7  0x7e000 0x2000
+
+    echo read -P 8  0x80000 0x6000
+    echo read -P 80 0x86000 0x2000
+    echo read -P 8  0x88000 0x2000
+    echo read -P 81 0x8a000 0xe000
+    echo read -P 90 0x98000 0x6000
+    echo read -P 9  0x9e000 0x2000
+
+    echo read -P 10  0xa0000 0x6000
+    echo read -P 100 0xa6000 0x2000
+    echo read -P 10  0xa8000 0x2000
+    echo read -P 101 0xaa000 0xe000
+    echo read -P 110 0xb8000 0x8000
+}
+
+verify_io | $QEMU_IO $TEST_IMG | _filter_qemu_io
+
+_check_test_img
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/046.out b/tests/qemu-iotests/046.out
new file mode 100644
index 0000000..565360f
--- /dev/null
+++ b/tests/qemu-iotests/046.out
@@ -0,0 +1,163 @@
+QA output created by 046
+
+== creating backing file for COW tests ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728 
+qemu-io> wrote 65536/65536 bytes at offset 0
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 65536
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 131072
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 196608
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 262144
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 327680
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 393216
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 458752
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 524288
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 589824
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 655360
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 720896
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 786432
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 851968
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 917504
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset 983040
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=6442450944 backing_file='TEST_DIR/t.IMGFMT.base' 
+
+== Some concurrent requests touching the same cluster ==
+qemu-io> qemu-io> qemu-io> blkdebug: Suspended request 'A'
+qemu-io> qemu-io> qemu-io> qemu-io> qemu-io> blkdebug: Resuming request 'A'
+qemu-io> wrote 8192/8192 bytes at offset XXX
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 8192/8192 bytes at offset XXX
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 8192/8192 bytes at offset XXX
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> qemu-io> blkdebug: Suspended request 'A'
+qemu-io> qemu-io> qemu-io> blkdebug: Resuming request 'A'
+qemu-io> wrote 8192/8192 bytes at offset XXX
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 65536/65536 bytes at offset XXX
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> qemu-io> blkdebug: Suspended request 'A'
+qemu-io> qemu-io> qemu-io> blkdebug: Resuming request 'A'
+qemu-io> wrote 8192/8192 bytes at offset XXX
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 65536/65536 bytes at offset XXX
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 32768/32768 bytes at offset XXX
+32 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> qemu-io> qemu-io> blkdebug: Suspended request 'A'
+qemu-io> qemu-io> qemu-io> blkdebug: Resuming request 'A'
+qemu-io> wrote 8192/8192 bytes at offset XXX
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 57344/57344 bytes at offset XXX
+56 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 4096/4096 bytes at offset XXX
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 32768/32768 bytes at offset XXX
+32 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> qemu-io> discard 65536/65536 bytes at offset XXX
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> qemu-io> qemu-io> blkdebug: Suspended request 'A'
+qemu-io> qemu-io> qemu-io> blkdebug: Resuming request 'A'
+qemu-io> wrote 8192/8192 bytes at offset XXX
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 57344/57344 bytes at offset XXX
+56 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 4096/4096 bytes at offset XXX
+4 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> wrote 65536/65536 bytes at offset XXX
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> qemu-io> discard 65536/65536 bytes at offset XXX
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> qemu-io> qemu-io> blkdebug: Suspended request 'A'
+qemu-io> qemu-io> qemu-io> blkdebug: Resuming request 'A'
+qemu-io> wrote 8192/8192 bytes at offset XXX
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+wrote 57344/57344 bytes at offset XXX
+56 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> 
+== Verify image content ==
+qemu-io> read 65536/65536 bytes at offset 0
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 65536
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 73728
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 16384/16384 bytes at offset 81920
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 98304
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 106496
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 114688
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 122880
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 32768/32768 bytes at offset 131072
+32 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 163840
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 65536/65536 bytes at offset 172032
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 24576/24576 bytes at offset 237568
+24 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 32768/32768 bytes at offset 262144
+32 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 294912
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 303104
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 65536/65536 bytes at offset 311296
+64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 16384/16384 bytes at offset 376832
+16 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 24576/24576 bytes at offset 393216
+24 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 417792
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 425984
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 57344/57344 bytes at offset 434176
+56 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 24576/24576 bytes at offset 491520
+24 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 516096
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 24576/24576 bytes at offset 524288
+24 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 548864
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 557056
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 57344/57344 bytes at offset 565248
+56 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 24576/24576 bytes at offset 622592
+24 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 647168
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 24576/24576 bytes at offset 655360
+24 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 679936
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 8192/8192 bytes at offset 688128
+8 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 57344/57344 bytes at offset 696320
+56 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> read 32768/32768 bytes at offset 753664
+32 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+qemu-io> No errors were found on the image.
+*** done
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index a4a9044..a0307de 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -51,3 +51,5 @@
 042 rw auto quick
 043 rw auto backing
 044 rw auto
+045 rw auto
+046 rw auto aio
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index 0be5c7e..569ca3d 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -79,6 +79,18 @@ class VM(object):
         self._num_drives += 1
         return self
 
+    def add_fd(self, fd, fdset, opaque, opts=''):
+        '''Pass a file descriptor to the VM'''
+        options = ['fd=%d' % fd,
+                   'set=%d' % fdset,
+                   'opaque=%s' % opaque]
+        if opts:
+            options.append(opts)
+
+        self._args.append('-add-fd')
+        self._args.append(','.join(options))
+        return self
+
     def launch(self):
         '''Launch the VM and establish a QMP connection'''
         devnull = open('/dev/null', 'rb')
diff --git a/tests/test-aio.c b/tests/test-aio.c
index f53c908..a8a4f0c 100644
--- a/tests/test-aio.c
+++ b/tests/test-aio.c
@@ -15,6 +15,14 @@
 
 AioContext *ctx;
 
+/* Wait until there are no more BHs or AIO requests */
+static void wait_for_aio(void)
+{
+    while (aio_poll(ctx, true)) {
+        /* Do nothing */
+    }
+}
+
 /* Simple callbacks for testing.  */
 
 typedef struct {
@@ -78,14 +86,6 @@ static void test_notify(void)
     g_assert(!aio_poll(ctx, false));
 }
 
-static void test_flush(void)
-{
-    g_assert(!aio_poll(ctx, false));
-    aio_notify(ctx);
-    aio_flush(ctx);
-    g_assert(!aio_poll(ctx, false));
-}
-
 static void test_bh_schedule(void)
 {
     BHTestData data = { .n = 0 };
@@ -116,7 +116,7 @@ static void test_bh_schedule10(void)
     g_assert(aio_poll(ctx, true));
     g_assert_cmpint(data.n, ==, 2);
 
-    aio_flush(ctx);
+    wait_for_aio();
     g_assert_cmpint(data.n, ==, 10);
 
     g_assert(!aio_poll(ctx, false));
@@ -164,7 +164,7 @@ static void test_bh_delete_from_cb(void)
     qemu_bh_schedule(data1.bh);
     g_assert_cmpint(data1.n, ==, 0);
 
-    aio_flush(ctx);
+    wait_for_aio();
     g_assert_cmpint(data1.n, ==, data1.max);
     g_assert(data1.bh == NULL);
 
@@ -200,7 +200,7 @@ static void test_bh_delete_from_cb_many(void)
     g_assert_cmpint(data4.n, ==, 1);
     g_assert(data1.bh == NULL);
 
-    aio_flush(ctx);
+    wait_for_aio();
     g_assert_cmpint(data1.n, ==, data1.max);
     g_assert_cmpint(data2.n, ==, data2.max);
     g_assert_cmpint(data3.n, ==, data3.max);
@@ -219,7 +219,7 @@ static void test_bh_flush(void)
     qemu_bh_schedule(data.bh);
     g_assert_cmpint(data.n, ==, 0);
 
-    aio_flush(ctx);
+    wait_for_aio();
     g_assert_cmpint(data.n, ==, 1);
 
     g_assert(!aio_poll(ctx, false));
@@ -281,7 +281,7 @@ static void test_flush_event_notifier(void)
     g_assert_cmpint(data.active, ==, 9);
     g_assert(aio_poll(ctx, false));
 
-    aio_flush(ctx);
+    wait_for_aio();
     g_assert_cmpint(data.n, ==, 10);
     g_assert_cmpint(data.active, ==, 0);
     g_assert(!aio_poll(ctx, false));
@@ -325,7 +325,7 @@ static void test_wait_event_notifier_noflush(void)
     g_assert_cmpint(data.n, ==, 2);
 
     event_notifier_set(&dummy.e);
-    aio_flush(ctx);
+    wait_for_aio();
     g_assert_cmpint(data.n, ==, 2);
     g_assert_cmpint(dummy.n, ==, 1);
     g_assert_cmpint(dummy.active, ==, 0);
@@ -346,7 +346,7 @@ static void test_wait_event_notifier_noflush(void)
  * - sometimes both the AioContext and the glib main loop wake
  *   themselves up.  Hence, some "g_assert(!aio_poll(ctx, false));"
  *   are replaced by "while (g_main_context_iteration(NULL, false));".
- * - there is no exact replacement for aio_flush's blocking wait.
+ * - there is no exact replacement for a blocking wait.
  *   "while (g_main_context_iteration(NULL, true)" seems to work,
  *   but it is not documented _why_ it works.  For these tests a
  *   non-blocking loop like "while (g_main_context_iteration(NULL, false)"
@@ -637,7 +637,6 @@ int main(int argc, char **argv)
 
     g_test_init(&argc, &argv, NULL);
     g_test_add_func("/aio/notify",                  test_notify);
-    g_test_add_func("/aio/flush",                   test_flush);
     g_test_add_func("/aio/bh/schedule",             test_bh_schedule);
     g_test_add_func("/aio/bh/schedule10",           test_bh_schedule10);
     g_test_add_func("/aio/bh/cancel",               test_bh_cancel);
diff --git a/tests/test-thread-pool.c b/tests/test-thread-pool.c
index fea0445..ea8e676 100644
--- a/tests/test-thread-pool.c
+++ b/tests/test-thread-pool.c
@@ -47,11 +47,19 @@ static void qemu_aio_wait_nonblocking(void)
     qemu_aio_wait();
 }
 
+/* Wait until all aio and bh activity has finished */
+static void qemu_aio_wait_all(void)
+{
+    while (qemu_aio_wait()) {
+        /* Do nothing */
+    }
+}
+
 static void test_submit(void)
 {
     WorkerTestData data = { .n = 0 };
     thread_pool_submit(worker_cb, &data);
-    qemu_aio_flush();
+    qemu_aio_wait_all();
     g_assert_cmpint(data.n, ==, 1);
 }
 
@@ -63,7 +71,7 @@ static void test_submit_aio(void)
     /* The callbacks are not called until after the first wait.  */
     active = 1;
     g_assert_cmpint(data.ret, ==, -EINPROGRESS);
-    qemu_aio_flush();
+    qemu_aio_wait_all();
     g_assert_cmpint(active, ==, 0);
     g_assert_cmpint(data.n, ==, 1);
     g_assert_cmpint(data.ret, ==, 0);
@@ -84,7 +92,7 @@ static void co_test_cb(void *opaque)
     data->ret = 0;
     active--;
 
-    /* The test continues in test_submit_co, after qemu_aio_flush... */
+    /* The test continues in test_submit_co, after qemu_aio_wait_all... */
 }
 
 static void test_submit_co(void)
@@ -99,9 +107,9 @@ static void test_submit_co(void)
     g_assert_cmpint(active, ==, 1);
     g_assert_cmpint(data.ret, ==, -EINPROGRESS);
 
-    /* qemu_aio_flush will execute the rest of the coroutine.  */
+    /* qemu_aio_wait_all will execute the rest of the coroutine.  */
 
-    qemu_aio_flush();
+    qemu_aio_wait_all();
 
     /* Back here after the coroutine has finished.  */
 
@@ -184,7 +192,7 @@ static void test_cancel(void)
     }
 
     /* Finish execution and execute any remaining callbacks.  */
-    qemu_aio_flush();
+    qemu_aio_wait_all();
     g_assert_cmpint(active, ==, 0);
     for (i = 0; i < 100; i++) {
         if (data[i].n == 3) {
diff --git a/vl.c b/vl.c
index a3ab384..3ebf01f 100644
--- a/vl.c
+++ b/vl.c
@@ -886,9 +886,9 @@ static int cleanup_add_fd(QemuOpts *opts, void *opaque)
 
 static int drive_init_func(QemuOpts *opts, void *opaque)
 {
-    int *use_scsi = opaque;
+    BlockInterfaceType *block_default_type = opaque;
 
-    return drive_init(opts, *use_scsi) == NULL;
+    return drive_init(opts, *block_default_type) == NULL;
 }
 
 static int drive_enable_snapshot(QemuOpts *opts, void *opaque)
@@ -899,16 +899,11 @@ static int drive_enable_snapshot(QemuOpts *opts, void *opaque)
     return 0;
 }
 
-static void default_drive(int enable, int snapshot, int use_scsi,
-                          BlockInterfaceType type, int index,
-                          const char *optstr)
+static void default_drive(int enable, int snapshot, BlockInterfaceType type,
+                          int index, const char *optstr)
 {
     QemuOpts *opts;
 
-    if (type == IF_DEFAULT) {
-        type = use_scsi ? IF_SCSI : IF_IDE;
-    }
-
     if (!enable || drive_get_by_index(type, index)) {
         return;
     }
@@ -917,7 +912,7 @@ static void default_drive(int enable, int snapshot, int use_scsi,
     if (snapshot) {
         drive_enable_snapshot(opts, NULL);
     }
-    if (!drive_init(opts, use_scsi)) {
+    if (!drive_init(opts, type)) {
         exit(1);
     }
 }
@@ -2001,7 +1996,7 @@ static int balloon_parse(const char *arg)
                 return  -1;
         } else {
             /* create empty opts */
-            opts = qemu_opts_create(qemu_find_opts("device"), NULL, 0, NULL);
+            opts = qemu_opts_create_nofail(qemu_find_opts("device"));
         }
         qemu_opt_set(opts, "driver", "virtio-balloon");
         return 0;
@@ -2251,14 +2246,14 @@ static int virtcon_parse(const char *devname)
         exit(1);
     }
 
-    bus_opts = qemu_opts_create(device, NULL, 0, NULL);
+    bus_opts = qemu_opts_create_nofail(device);
     if (arch_type == QEMU_ARCH_S390X) {
         qemu_opt_set(bus_opts, "driver", "virtio-serial-s390");
     } else {
         qemu_opt_set(bus_opts, "driver", "virtio-serial-pci");
     } 
 
-    dev_opts = qemu_opts_create(device, NULL, 0, NULL);
+    dev_opts = qemu_opts_create_nofail(device);
     qemu_opt_set(dev_opts, "driver", "virtconsole");
 
     snprintf(label, sizeof(label), "virtcon%d", index);
@@ -3110,8 +3105,7 @@ int main(int argc, char **argv, char **envp)
 
                 qemu_opt_set_bool(fsdev, "readonly",
                                 qemu_opt_get_bool(opts, "readonly", 0));
-                device = qemu_opts_create(qemu_find_opts("device"), NULL, 0,
-                                          NULL);
+                device = qemu_opts_create_nofail(qemu_find_opts("device"));
                 qemu_opt_set(device, "driver", "virtio-9p-pci");
                 qemu_opt_set(device, "fsdev",
                              qemu_opt_get(opts, "mount_tag"));
@@ -3131,8 +3125,7 @@ int main(int argc, char **argv, char **envp)
                 }
                 qemu_opt_set(fsdev, "fsdriver", "synth");
 
-                device = qemu_opts_create(qemu_find_opts("device"), NULL, 0,
-                                          NULL);
+                device = qemu_opts_create_nofail(qemu_find_opts("device"));
                 qemu_opt_set(device, "driver", "virtio-9p-pci");
                 qemu_opt_set(device, "fsdev", "v_synth");
                 qemu_opt_set(device, "mount_tag", "v_synth");
@@ -3770,15 +3763,15 @@ int main(int argc, char **argv, char **envp)
     /* open the virtual block devices */
     if (snapshot)
         qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot, NULL, 0);
-    if (qemu_opts_foreach(qemu_find_opts("drive"), drive_init_func, &machine->use_scsi, 1) != 0)
+    if (qemu_opts_foreach(qemu_find_opts("drive"), drive_init_func,
+                          &machine->block_default_type, 1) != 0) {
         exit(1);
+    }
 
-    default_drive(default_cdrom, snapshot, machine->use_scsi,
-                  IF_DEFAULT, 2, CDROM_OPTS);
-    default_drive(default_floppy, snapshot, machine->use_scsi,
-                  IF_FLOPPY, 0, FD_OPTS);
-    default_drive(default_sdcard, snapshot, machine->use_scsi,
-                  IF_SD, 0, SD_OPTS);
+    default_drive(default_cdrom, snapshot, machine->block_default_type, 2,
+                  CDROM_OPTS);
+    default_drive(default_floppy, snapshot, IF_FLOPPY, 0, FD_OPTS);
+    default_drive(default_sdcard, snapshot, IF_SD, 0, SD_OPTS);
 
     register_savevm_live(NULL, "ram", 0, 4, &savevm_ram_handlers, NULL);