Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into staging

Block pull request

# gpg: Signature made Wed 28 May 2014 13:31:15 BST using RSA key ID 81AB73C8
# gpg: Can't check signature: public key not found

* remotes/stefanha/tags/block-pull-request: (33 commits)
  block/sheepdog: Don't use qerror_report()
  block/sheepdog: Fix silent sd_open(), sd_create() failures
  block/sheepdog: Propagate errors to open and create methods
  block/sheepdog: Propagate errors through find_vdi_name()
  block/sheepdog: Propagate errors through do_sd_create()
  block/sheepdog: Propagate errors through sd_prealloc()
  block/sheepdog: Propagate errors through get_sheep_fd()
  block/sheepdog: Propagate errors through connect_to_sdog()
  block/vvfat: Propagate errors through init_directories()
  block/vvfat: Propagate errors through enable_write_target()
  block/ssh: Propagate errors to open and create methods
  block/ssh: Propagate errors through connect_to_ssh()
  block/ssh: Propagate errors through authenticate()
  block/ssh: Propagate errors through check_host_key()
  block/ssh: Drop superfluous libssh2_session_last_errno() calls
  block/rbd: Propagate errors to open and create methods
  qemu-nbd: Don't use qerror_report()
  blockdev: Don't use qerror_report() in do_drive_del()
  blockdev: Don't use qerror_report_err() in drive_init()
  docs: Define refcount_bits value
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

24 files changed, 906 insertions, 247 deletions

diff --git a/block-migration.c b/block-migration.c
index 56951e09ae..16562709c8 100644
--- a/block-migration.c
+++ b/block-migration.c
@@ -59,6 +59,7 @@ typedef struct BlkMigDevState {
     unsigned long *aio_bitmap;
     int64_t completed_sectors;
     BdrvDirtyBitmap *dirty_bitmap;
+    Error *blocker;
 } BlkMigDevState;
 
 typedef struct BlkMigBlock {
@@ -361,7 +362,8 @@ static void init_blk_migration_it(void *opaque, BlockDriverState *bs)
         bmds->completed_sectors = 0;
         bmds->shared_base = block_mig_state.shared_base;
         alloc_aio_bitmap(bmds);
-        bdrv_set_in_use(bs, 1);
+        error_setg(&bmds->blocker, "block device is in use by migration");
+        bdrv_op_block_all(bs, bmds->blocker);
         bdrv_ref(bs);
 
         block_mig_state.total_sector_sum += sectors;
@@ -599,7 +601,8 @@ static void blk_mig_cleanup(void)
     blk_mig_lock();
     while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {
         QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry);
-        bdrv_set_in_use(bmds->bs, 0);
+        bdrv_op_unblock_all(bmds->bs, bmds->blocker);
+        error_free(bmds->blocker);
         bdrv_unref(bmds->bs);
         g_free(bmds->aio_bitmap);
         g_free(bmds);
diff --git a/block.c b/block.c
index 40c5e1aa73..a517d72d71 100644
--- a/block.c
+++ b/block.c
@@ -335,6 +335,7 @@ void bdrv_register(BlockDriver *bdrv)
 BlockDriverState *bdrv_new(const char *device_name, Error **errp)
 {
     BlockDriverState *bs;
+    int i;
 
     if (bdrv_find(device_name)) {
         error_setg(errp, "Device with id '%s' already exists",
@@ -353,6 +354,9 @@ BlockDriverState *bdrv_new(const char *device_name, Error **errp)
     if (device_name[0] != '\0') {
         QTAILQ_INSERT_TAIL(&bdrv_states, bs, device_list);
     }
+    for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
+        QLIST_INIT(&bs->op_blockers[i]);
+    }
     bdrv_iostatus_disable(bs);
     notifier_list_init(&bs->close_notifiers);
     notifier_with_return_list_init(&bs->before_write_notifiers);
@@ -1090,6 +1094,37 @@ fail:
     return ret;
 }
 
+void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd)
+{
+
+    if (bs->backing_hd) {
+        assert(bs->backing_blocker);
+        bdrv_op_unblock_all(bs->backing_hd, bs->backing_blocker);
+    } else if (backing_hd) {
+        error_setg(&bs->backing_blocker,
+                   "device is used as backing hd of '%s'",
+                   bs->device_name);
+    }
+
+    bs->backing_hd = backing_hd;
+    if (!backing_hd) {
+        error_free(bs->backing_blocker);
+        bs->backing_blocker = NULL;
+        goto out;
+    }
+    bs->open_flags &= ~BDRV_O_NO_BACKING;
+    pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_hd->filename);
+    pstrcpy(bs->backing_format, sizeof(bs->backing_format),
+            backing_hd->drv ? backing_hd->drv->format_name : "");
+
+    bdrv_op_block_all(bs->backing_hd, bs->backing_blocker);
+    /* Otherwise we won't be able to commit due to check in bdrv_commit */
+    bdrv_op_unblock(bs->backing_hd, BLOCK_OP_TYPE_COMMIT,
+                    bs->backing_blocker);
+out:
+    bdrv_refresh_limits(bs);
+}
+
 /*
  * Opens the backing file for a BlockDriverState if not yet open
  *
@@ -1103,6 +1138,7 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp)
     char *backing_filename = g_malloc0(PATH_MAX);
     int ret = 0;
     BlockDriver *back_drv = NULL;
+    BlockDriverState *backing_hd;
     Error *local_err = NULL;
 
     if (bs->backing_hd != NULL) {
@@ -1125,30 +1161,26 @@ int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp)
         bdrv_get_full_backing_filename(bs, backing_filename, PATH_MAX);
     }
 
+    backing_hd = bdrv_new("", errp);
+
     if (bs->backing_format[0] != '\0') {
         back_drv = bdrv_find_format(bs->backing_format);
     }
 
     assert(bs->backing_hd == NULL);
-    ret = bdrv_open(&bs->backing_hd,
+    ret = bdrv_open(&backing_hd,
                     *backing_filename ? backing_filename : NULL, NULL, options,
                     bdrv_backing_flags(bs->open_flags), back_drv, &local_err);
     if (ret < 0) {
-        bs->backing_hd = NULL;
+        bdrv_unref(backing_hd);
+        backing_hd = NULL;
         bs->open_flags |= BDRV_O_NO_BACKING;
         error_setg(errp, "Could not open backing file: %s",
                    error_get_pretty(local_err));
         error_free(local_err);
         goto free_exit;
     }
-
-    if (bs->backing_hd->file) {
-        pstrcpy(bs->backing_file, sizeof(bs->backing_file),
-                bs->backing_hd->file->filename);
-    }
-
-    /* Recalculate the BlockLimits with the backing file */
-    bdrv_refresh_limits(bs);
+    bdrv_set_backing_hd(bs, backing_hd);
 
 free_exit:
     g_free(backing_filename);
@@ -1784,8 +1816,9 @@ void bdrv_close(BlockDriverState *bs)
 
     if (bs->drv) {
         if (bs->backing_hd) {
-            bdrv_unref(bs->backing_hd);
-            bs->backing_hd = NULL;
+            BlockDriverState *backing_hd = bs->backing_hd;
+            bdrv_set_backing_hd(bs, NULL);
+            bdrv_unref(backing_hd);
         }
         bs->drv->bdrv_close(bs);
         g_free(bs->opaque);
@@ -1945,13 +1978,14 @@ static void bdrv_move_feature_fields(BlockDriverState *bs_dest,
     bs_dest->refcnt             = bs_src->refcnt;
 
     /* job */
-    bs_dest->in_use             = bs_src->in_use;
     bs_dest->job                = bs_src->job;
 
     /* keep the same entry in bdrv_states */
     pstrcpy(bs_dest->device_name, sizeof(bs_dest->device_name),
             bs_src->device_name);
     bs_dest->device_list = bs_src->device_list;
+    memcpy(bs_dest->op_blockers, bs_src->op_blockers,
+           sizeof(bs_dest->op_blockers));
 }
 
 /*
@@ -1986,7 +2020,6 @@ void bdrv_swap(BlockDriverState *bs_new, BlockDriverState *bs_old)
     assert(QLIST_EMPTY(&bs_new->dirty_bitmaps));
     assert(bs_new->job == NULL);
     assert(bs_new->dev == NULL);
-    assert(bs_new->in_use == 0);
     assert(bs_new->io_limits_enabled == false);
     assert(!throttle_have_timer(&bs_new->throttle_state));
 
@@ -2005,7 +2038,6 @@ void bdrv_swap(BlockDriverState *bs_new, BlockDriverState *bs_old)
     /* Check a few fields that should remain attached to the device */
     assert(bs_new->dev == NULL);
     assert(bs_new->job == NULL);
-    assert(bs_new->in_use == 0);
     assert(bs_new->io_limits_enabled == false);
     assert(!throttle_have_timer(&bs_new->throttle_state));
 
@@ -2038,19 +2070,14 @@ void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top)
 
     /* The contents of 'tmp' will become bs_top, as we are
      * swapping bs_new and bs_top contents. */
-    bs_top->backing_hd = bs_new;
-    bs_top->open_flags &= ~BDRV_O_NO_BACKING;
-    pstrcpy(bs_top->backing_file, sizeof(bs_top->backing_file),
-            bs_new->filename);
-    pstrcpy(bs_top->backing_format, sizeof(bs_top->backing_format),
-            bs_new->drv ? bs_new->drv->format_name : "");
+    bdrv_set_backing_hd(bs_top, bs_new);
 }
 
 static void bdrv_delete(BlockDriverState *bs)
 {
     assert(!bs->dev);
     assert(!bs->job);
-    assert(!bs->in_use);
+    assert(bdrv_op_blocker_is_empty(bs));
     assert(!bs->refcnt);
     assert(QLIST_EMPTY(&bs->dirty_bitmaps));
 
@@ -2232,7 +2259,8 @@ int bdrv_commit(BlockDriverState *bs)
         return -ENOTSUP;
     }
 
-    if (bdrv_in_use(bs) || bdrv_in_use(bs->backing_hd)) {
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT, NULL) ||
+        bdrv_op_is_blocked(bs->backing_hd, BLOCK_OP_TYPE_COMMIT, NULL)) {
         return -EBUSY;
     }
 
@@ -2636,13 +2664,11 @@ int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
     if (ret) {
         goto exit;
     }
-    new_top_bs->backing_hd = base_bs;
-
-    bdrv_refresh_limits(new_top_bs);
+    bdrv_set_backing_hd(new_top_bs, base_bs);
 
     QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) {
         /* so that bdrv_close() does not recursively close the chain */
-        intermediate_state->bs->backing_hd = NULL;
+        bdrv_set_backing_hd(intermediate_state->bs, NULL);
         bdrv_unref(intermediate_state->bs);
     }
     ret = 0;
@@ -3494,8 +3520,9 @@ int bdrv_truncate(BlockDriverState *bs, int64_t offset)
         return -ENOTSUP;
     if (bs->read_only)
         return -EACCES;
-    if (bdrv_in_use(bs))
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_RESIZE, NULL)) {
         return -EBUSY;
+    }
     ret = drv->bdrv_truncate(bs, offset);
     if (ret == 0) {
         ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
@@ -5325,15 +5352,74 @@ void bdrv_unref(BlockDriverState *bs)
     }
 }
 
-void bdrv_set_in_use(BlockDriverState *bs, int in_use)
+struct BdrvOpBlocker {
+    Error *reason;
+    QLIST_ENTRY(BdrvOpBlocker) list;
+};
+
+bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp)
+{
+    BdrvOpBlocker *blocker;
+    assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
+    if (!QLIST_EMPTY(&bs->op_blockers[op])) {
+        blocker = QLIST_FIRST(&bs->op_blockers[op]);
+        if (errp) {
+            error_setg(errp, "Device '%s' is busy: %s",
+                       bs->device_name, error_get_pretty(blocker->reason));
+        }
+        return true;
+    }
+    return false;
+}
+
+void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason)
 {
-    assert(bs->in_use != in_use);
-    bs->in_use = in_use;
+    BdrvOpBlocker *blocker;
+    assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
+
+    blocker = g_malloc0(sizeof(BdrvOpBlocker));
+    blocker->reason = reason;
+    QLIST_INSERT_HEAD(&bs->op_blockers[op], blocker, list);
 }
 
-int bdrv_in_use(BlockDriverState *bs)
+void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason)
 {
-    return bs->in_use;
+    BdrvOpBlocker *blocker, *next;
+    assert((int) op >= 0 && op < BLOCK_OP_TYPE_MAX);
+    QLIST_FOREACH_SAFE(blocker, &bs->op_blockers[op], list, next) {
+        if (blocker->reason == reason) {
+            QLIST_REMOVE(blocker, list);
+            g_free(blocker);
+        }
+    }
+}
+
+void bdrv_op_block_all(BlockDriverState *bs, Error *reason)
+{
+    int i;
+    for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
+        bdrv_op_block(bs, i, reason);
+    }
+}
+
+void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason)
+{
+    int i;
+    for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
+        bdrv_op_unblock(bs, i, reason);
+    }
+}
+
+bool bdrv_op_blocker_is_empty(BlockDriverState *bs)
+{
+    int i;
+
+    for (i = 0; i < BLOCK_OP_TYPE_MAX; i++) {
+        if (!QLIST_EMPTY(&bs->op_blockers[i])) {
+            return false;
+        }
+    }
+    return true;
 }
 
 void bdrv_iostatus_enable(BlockDriverState *bs)
diff --git a/block/mirror.c b/block/mirror.c
index 1c38aa8f77..94c8661777 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -498,7 +498,7 @@ immediate_exit:
             /* drop the bs loop chain formed by the swap: break the loop then
              * trigger the unref from the top one */
             BlockDriverState *p = s->base->backing_hd;
-            s->base->backing_hd = NULL;
+            bdrv_set_backing_hd(s->base, NULL);
             bdrv_unref(p);
         }
     }
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 76d2bcf63a..4208dc08b5 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -379,7 +379,8 @@ static int coroutine_fn copy_sectors(BlockDriverState *bs,
     BLKDBG_EVENT(bs->file, BLKDBG_COW_READ);
 
     if (!bs->drv) {
-        return -ENOMEDIUM;
+        ret = -ENOMEDIUM;
+        goto out;
     }
 
     /* Call .bdrv_co_readv() directly instead of using the public block-layer
diff --git a/block/rbd.c b/block/rbd.c
index dbc79f4525..09af48426e 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -105,7 +105,7 @@ typedef struct BDRVRBDState {
 static int qemu_rbd_next_tok(char *dst, int dst_len,
                              char *src, char delim,
                              const char *name,
-                             char **p)
+                             char **p, Error **errp)
 {
     int l;
     char *end;
@@ -128,10 +128,10 @@ static int qemu_rbd_next_tok(char *dst, int dst_len,
     }
     l = strlen(src);
     if (l >= dst_len) {
-        error_report("%s too long", name);
+        error_setg(errp, "%s too long", name);
         return -EINVAL;
     } else if (l == 0) {
-        error_report("%s too short", name);
+        error_setg(errp, "%s too short", name);
         return -EINVAL;
     }
 
@@ -157,13 +157,15 @@ static int qemu_rbd_parsename(const char *filename,
                               char *pool, int pool_len,
                               char *snap, int snap_len,
                               char *name, int name_len,
-                              char *conf, int conf_len)
+                              char *conf, int conf_len,
+                              Error **errp)
 {
     const char *start;
     char *p, *buf;
     int ret;
 
     if (!strstart(filename, "rbd:", &start)) {
+        error_setg(errp, "File name must start with 'rbd:'");
         return -EINVAL;
     }
 
@@ -172,7 +174,8 @@ static int qemu_rbd_parsename(const char *filename,
     *snap = '\0';
     *conf = '\0';
 
-    ret = qemu_rbd_next_tok(pool, pool_len, p, '/', "pool name", &p);
+    ret = qemu_rbd_next_tok(pool, pool_len, p,
+                            '/', "pool name", &p, errp);
     if (ret < 0 || !p) {
         ret = -EINVAL;
         goto done;
@@ -180,21 +183,25 @@ static int qemu_rbd_parsename(const char *filename,
     qemu_rbd_unescape(pool);
 
     if (strchr(p, '@')) {
-        ret = qemu_rbd_next_tok(name, name_len, p, '@', "object name", &p);
+        ret = qemu_rbd_next_tok(name, name_len, p,
+                                '@', "object name", &p, errp);
         if (ret < 0) {
             goto done;
         }
-        ret = qemu_rbd_next_tok(snap, snap_len, p, ':', "snap name", &p);
+        ret = qemu_rbd_next_tok(snap, snap_len, p,
+                                ':', "snap name", &p, errp);
         qemu_rbd_unescape(snap);
     } else {
-        ret = qemu_rbd_next_tok(name, name_len, p, ':', "object name", &p);
+        ret = qemu_rbd_next_tok(name, name_len, p,
+                                ':', "object name", &p, errp);
     }
     qemu_rbd_unescape(name);
     if (ret < 0 || !p) {
         goto done;
     }
 
-    ret = qemu_rbd_next_tok(conf, conf_len, p, '\0', "configuration", &p);
+    ret = qemu_rbd_next_tok(conf, conf_len, p,
+                            '\0', "configuration", &p, errp);
 
 done:
     g_free(buf);
@@ -229,7 +236,7 @@ static char *qemu_rbd_parse_clientname(const char *conf, char *clientname)
     return NULL;
 }
 
-static int qemu_rbd_set_conf(rados_t cluster, const char *conf)
+static int qemu_rbd_set_conf(rados_t cluster, const char *conf, Error **errp)
 {
     char *p, *buf;
     char name[RBD_MAX_CONF_NAME_SIZE];
@@ -241,20 +248,20 @@ static int qemu_rbd_set_conf(rados_t cluster, const char *conf)
 
     while (p) {
         ret = qemu_rbd_next_tok(name, sizeof(name), p,
-                                '=', "conf option name", &p);
+                                '=', "conf option name", &p, errp);
         if (ret < 0) {
             break;
         }
         qemu_rbd_unescape(name);
 
         if (!p) {
-            error_report("conf option %s has no value", name);
+            error_setg(errp, "conf option %s has no value", name);
             ret = -EINVAL;
             break;
         }
 
         ret = qemu_rbd_next_tok(value, sizeof(value), p,
-                                ':', "conf option value", &p);
+                                ':', "conf option value", &p, errp);
         if (ret < 0) {
             break;
         }
@@ -263,7 +270,7 @@ static int qemu_rbd_set_conf(rados_t cluster, const char *conf)
         if (strcmp(name, "conf") == 0) {
             ret = rados_conf_read_file(cluster, value);
             if (ret < 0) {
-                error_report("error reading conf file %s", value);
+                error_setg(errp, "error reading conf file %s", value);
                 break;
             }
         } else if (strcmp(name, "id") == 0) {
@@ -271,7 +278,7 @@ static int qemu_rbd_set_conf(rados_t cluster, const char *conf)
         } else {
             ret = rados_conf_set(cluster, name, value);
             if (ret < 0) {
-                error_report("invalid conf option %s", name);
+                error_setg(errp, "invalid conf option %s", name);
                 ret = -EINVAL;
                 break;
             }
@@ -285,6 +292,7 @@ static int qemu_rbd_set_conf(rados_t cluster, const char *conf)
 static int qemu_rbd_create(const char *filename, QEMUOptionParameter *options,
                            Error **errp)
 {
+    Error *local_err = NULL;
     int64_t bytes = 0;
     int64_t objsize;
     int obj_order = 0;
@@ -301,7 +309,8 @@ static int qemu_rbd_create(const char *filename, QEMUOptionParameter *options,
     if (qemu_rbd_parsename(filename, pool, sizeof(pool),
                            snap_buf, sizeof(snap_buf),
                            name, sizeof(name),
-                           conf, sizeof(conf)) < 0) {
+                           conf, sizeof(conf), &local_err) < 0) {
+        error_propagate(errp, local_err);
         return -EINVAL;
     }
 
@@ -313,11 +322,11 @@ static int qemu_rbd_create(const char *filename, QEMUOptionParameter *options,
             if (options->value.n) {
                 objsize = options->value.n;
                 if ((objsize - 1) & objsize) {    /* not a power of 2? */
-                    error_report("obj size needs to be power of 2");
+                    error_setg(errp, "obj size needs to be power of 2");
                     return -EINVAL;
                 }
                 if (objsize < 4096) {
-                    error_report("obj size too small");
+                    error_setg(errp, "obj size too small");
                     return -EINVAL;
                 }
                 obj_order = ffs(objsize) - 1;
@@ -328,7 +337,7 @@ static int qemu_rbd_create(const char *filename, QEMUOptionParameter *options,
 
     clientname = qemu_rbd_parse_clientname(conf, clientname_buf);
     if (rados_create(&cluster, clientname) < 0) {
-        error_report("error initializing");
+        error_setg(errp, "error initializing");
         return -EIO;
     }
 
@@ -338,20 +347,20 @@ static int qemu_rbd_create(const char *filename, QEMUOptionParameter *options,
     }
 
     if (conf[0] != '\0' &&
-        qemu_rbd_set_conf(cluster, conf) < 0) {
-        error_report("error setting config options");
+        qemu_rbd_set_conf(cluster, conf, &local_err) < 0) {
         rados_shutdown(cluster);
+        error_propagate(errp, local_err);
         return -EIO;
     }
 
     if (rados_connect(cluster) < 0) {
-        error_report("error connecting");
+        error_setg(errp, "error connecting");
         rados_shutdown(cluster);
         return -EIO;
     }
 
     if (rados_ioctx_create(cluster, pool, &io_ctx) < 0) {
-        error_report("error opening pool %s", pool);
+        error_setg(errp, "error opening pool %s", pool);
         rados_shutdown(cluster);
         return -EIO;
     }
@@ -441,8 +450,7 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
     qemu_opts_absorb_qdict(opts, options, &local_err);
     if (local_err) {
-        qerror_report_err(local_err);
-        error_free(local_err);
+        error_propagate(errp, local_err);
         qemu_opts_del(opts);
         return -EINVAL;
     }
@@ -452,7 +460,7 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
     if (qemu_rbd_parsename(filename, pool, sizeof(pool),
                            snap_buf, sizeof(snap_buf),
                            s->name, sizeof(s->name),
-                           conf, sizeof(conf)) < 0) {
+                           conf, sizeof(conf), errp) < 0) {
         r = -EINVAL;
         goto failed_opts;
     }
@@ -460,7 +468,7 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
     clientname = qemu_rbd_parse_clientname(conf, clientname_buf);
     r = rados_create(&s->cluster, clientname);
     if (r < 0) {
-        error_report("error initializing");
+        error_setg(&local_err, "error initializing");
         goto failed_opts;
     }
 
@@ -488,28 +496,27 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     if (conf[0] != '\0') {
-        r = qemu_rbd_set_conf(s->cluster, conf);
+        r = qemu_rbd_set_conf(s->cluster, conf, errp);
         if (r < 0) {
-            error_report("error setting config options");
             goto failed_shutdown;
         }
     }
 
     r = rados_connect(s->cluster);
     if (r < 0) {
-        error_report("error connecting");
+        error_setg(&local_err, "error connecting");
         goto failed_shutdown;
     }
 
     r = rados_ioctx_create(s->cluster, pool, &s->io_ctx);
     if (r < 0) {
-        error_report("error opening pool %s", pool);
+        error_setg(&local_err, "error opening pool %s", pool);
         goto failed_shutdown;
     }
 
     r = rbd_open(s->io_ctx, s->name, &s->image, s->snap);
     if (r < 0) {
-        error_report("error reading header from %s", s->name);
+        error_setg(&local_err, "error reading header from %s", s->name);
         goto failed_open;
     }
 
diff --git a/block/sheepdog.c b/block/sheepdog.c
index 2c3fb016a8..39f746157a 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -526,17 +526,16 @@ static SheepdogAIOCB *sd_aio_setup(BlockDriverState *bs, QEMUIOVector *qiov,
     return acb;
 }
 
-static int connect_to_sdog(BDRVSheepdogState *s)
+static int connect_to_sdog(BDRVSheepdogState *s, Error **errp)
 {
     int fd;
-    Error *err = NULL;
 
     if (s->is_unix) {
-        fd = unix_connect(s->host_spec, &err);
+        fd = unix_connect(s->host_spec, errp);
     } else {
-        fd = inet_connect(s->host_spec, &err);
+        fd = inet_connect(s->host_spec, errp);
 
-        if (err == NULL) {
+        if (fd >= 0) {
             int ret = socket_set_nodelay(fd);
             if (ret < 0) {
                 error_report("%s", strerror(errno));
@@ -544,10 +543,7 @@ static int connect_to_sdog(BDRVSheepdogState *s)
         }
     }
 
-    if (err != NULL) {
-        qerror_report_err(err);
-        error_free(err);
-    } else {
+    if (fd >= 0) {
         qemu_set_nonblock(fd);
     }
 
@@ -672,7 +668,7 @@ static void coroutine_fn add_aio_request(BDRVSheepdogState *s, AIOReq *aio_req,
                            enum AIOCBState aiocb_type);
 static void coroutine_fn resend_aioreq(BDRVSheepdogState *s, AIOReq *aio_req);
 static int reload_inode(BDRVSheepdogState *s, uint32_t snapid, const char *tag);
-static int get_sheep_fd(BDRVSheepdogState *s);
+static int get_sheep_fd(BDRVSheepdogState *s, Error **errp);
 static void co_write_request(void *opaque);
 
 static AIOReq *find_pending_req(BDRVSheepdogState *s, uint64_t oid)
@@ -709,6 +705,7 @@ static void coroutine_fn send_pending_req(BDRVSheepdogState *s, uint64_t oid)
 
 static coroutine_fn void reconnect_to_sdog(void *opaque)
 {
+    Error *local_err = NULL;
     BDRVSheepdogState *s = opaque;
     AIOReq *aio_req, *next;
 
@@ -723,9 +720,11 @@ static coroutine_fn void reconnect_to_sdog(void *opaque)
 
     /* Try to reconnect the sheepdog server every one second. */
     while (s->fd < 0) {
-        s->fd = get_sheep_fd(s);
+        s->fd = get_sheep_fd(s, &local_err);
         if (s->fd < 0) {
             DPRINTF("Wait for connection to be established\n");
+            error_report("%s", error_get_pretty(local_err));
+            error_free(local_err);
             co_aio_sleep_ns(bdrv_get_aio_context(s->bs), QEMU_CLOCK_REALTIME,
                             1000000000ULL);
         }
@@ -914,11 +913,11 @@ static void co_write_request(void *opaque)
  * We cannot use this descriptor for other operations because
  * the block driver may be on waiting response from the server.
  */
-static int get_sheep_fd(BDRVSheepdogState *s)
+static int get_sheep_fd(BDRVSheepdogState *s, Error **errp)
 {
     int fd;
 
-    fd = connect_to_sdog(s);
+    fd = connect_to_sdog(s, errp);
     if (fd < 0) {
         return fd;
     }
@@ -1061,7 +1060,7 @@ static int parse_vdiname(BDRVSheepdogState *s, const char *filename,
 
 static int find_vdi_name(BDRVSheepdogState *s, const char *filename,
                          uint32_t snapid, const char *tag, uint32_t *vid,
-                         bool lock)
+                         bool lock, Error **errp)
 {
     int ret, fd;
     SheepdogVdiReq hdr;
@@ -1069,7 +1068,7 @@ static int find_vdi_name(BDRVSheepdogState *s, const char *filename,
     unsigned int wlen, rlen = 0;
     char buf[SD_MAX_VDI_LEN + SD_MAX_VDI_TAG_LEN];
 
-    fd = connect_to_sdog(s);
+    fd = connect_to_sdog(s, errp);
     if (fd < 0) {
         return fd;
     }
@@ -1095,12 +1094,13 @@ static int find_vdi_name(BDRVSheepdogState *s, const char *filename,
 
     ret = do_req(fd, (SheepdogReq *)&hdr, buf, &wlen, &rlen);
     if (ret) {
+        error_setg_errno(errp, -ret, "cannot get vdi info");
         goto out;
     }
 
     if (rsp->result != SD_RES_SUCCESS) {
-        error_report("cannot get vdi info, %s, %s %" PRIu32 " %s",
-                     sd_strerror(rsp->result), filename, snapid, tag);
+        error_setg(errp, "cannot get vdi info, %s, %s %" PRIu32 " %s",
+                   sd_strerror(rsp->result), filename, snapid, tag);
         if (rsp->result == SD_RES_NO_VDI) {
             ret = -ENOENT;
         } else {
@@ -1263,19 +1263,24 @@ static int write_object(int fd, char *buf, uint64_t oid, uint8_t copies,
 /* update inode with the latest state */
 static int reload_inode(BDRVSheepdogState *s, uint32_t snapid, const char *tag)
 {
+    Error *local_err = NULL;
     SheepdogInode *inode;
     int ret = 0, fd;
     uint32_t vid = 0;
 
-    fd = connect_to_sdog(s);
+    fd = connect_to_sdog(s, &local_err);
     if (fd < 0) {
+        error_report("%s", error_get_pretty(local_err));;
+        error_free(local_err);
         return -EIO;
     }
 
     inode = g_malloc(sizeof(s->inode));
 
-    ret = find_vdi_name(s, s->name, snapid, tag, &vid, false);
+    ret = find_vdi_name(s, s->name, snapid, tag, &vid, false, &local_err);
     if (ret) {
+        error_report("%s", error_get_pretty(local_err));;
+        error_free(local_err);
         goto out;
     }
 
@@ -1386,8 +1391,7 @@ static int sd_open(BlockDriverState *bs, QDict *options, int flags,
     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
     qemu_opts_absorb_qdict(opts, options, &local_err);
     if (local_err) {
-        qerror_report_err(local_err);
-        error_free(local_err);
+        error_propagate(errp, local_err);
         ret = -EINVAL;
         goto out;
     }
@@ -1408,15 +1412,16 @@ static int sd_open(BlockDriverState *bs, QDict *options, int flags,
         ret = parse_vdiname(s, filename, vdi, &snapid, tag);
     }
     if (ret < 0) {
+        error_setg(errp, "Can't parse filename");
         goto out;
     }
-    s->fd = get_sheep_fd(s);
+    s->fd = get_sheep_fd(s, errp);
     if (s->fd < 0) {
         ret = s->fd;
         goto out;
     }
 
-    ret = find_vdi_name(s, vdi, snapid, tag, &vid, true);
+    ret = find_vdi_name(s, vdi, snapid, tag, &vid, true, errp);
     if (ret) {
         goto out;
     }
@@ -1436,7 +1441,7 @@ static int sd_open(BlockDriverState *bs, QDict *options, int flags,
         s->is_snapshot = true;
     }
 
-    fd = connect_to_sdog(s);
+    fd = connect_to_sdog(s, errp);
     if (fd < 0) {
         ret = fd;
         goto out;
@@ -1449,6 +1454,7 @@ static int sd_open(BlockDriverState *bs, QDict *options, int flags,
     closesocket(fd);
 
     if (ret) {
+        error_setg(errp, "Can't read snapshot inode");
         goto out;
     }
 
@@ -1472,7 +1478,8 @@ out:
     return ret;
 }
 
-static int do_sd_create(BDRVSheepdogState *s, uint32_t *vdi_id, int snapshot)
+static int do_sd_create(BDRVSheepdogState *s, uint32_t *vdi_id, int snapshot,
+                        Error **errp)
 {
     SheepdogVdiReq hdr;
     SheepdogVdiRsp *rsp = (SheepdogVdiRsp *)&hdr;
@@ -1480,7 +1487,7 @@ static int do_sd_create(BDRVSheepdogState *s, uint32_t *vdi_id, int snapshot)
     unsigned int wlen, rlen = 0;
     char buf[SD_MAX_VDI_LEN];
 
-    fd = connect_to_sdog(s);
+    fd = connect_to_sdog(s, errp);
     if (fd < 0) {
         return fd;
     }
@@ -1510,11 +1517,12 @@ static int do_sd_create(BDRVSheepdogState *s, uint32_t *vdi_id, int snapshot)
     closesocket(fd);
 
     if (ret) {
+        error_setg_errno(errp, -ret, "create failed");
         return ret;
     }
 
     if (rsp->result != SD_RES_SUCCESS) {
-        error_report("%s, %s", sd_strerror(rsp->result), s->inode.name);
+        error_setg(errp, "%s, %s", sd_strerror(rsp->result), s->inode.name);
         return -EIO;
     }
 
@@ -1525,21 +1533,18 @@ static int do_sd_create(BDRVSheepdogState *s, uint32_t *vdi_id, int snapshot)
     return 0;
 }
 
-static int sd_prealloc(const char *filename)
+static int sd_prealloc(const char *filename, Error **errp)
 {
     BlockDriverState *bs = NULL;
     uint32_t idx, max_idx;
     int64_t vdi_size;
     void *buf = g_malloc0(SD_DATA_OBJ_SIZE);
-    Error *local_err = NULL;
     int ret;
 
     ret = bdrv_open(&bs, filename, NULL, NULL, BDRV_O_RDWR | BDRV_O_PROTOCOL,
-                    NULL, &local_err);
+                    NULL, errp);
     if (ret < 0) {
-        qerror_report_err(local_err);
-        error_free(local_err);
-        goto out;
+        goto out_with_err_set;
     }
 
     vdi_size = bdrv_getlength(bs);
@@ -1563,7 +1568,12 @@ static int sd_prealloc(const char *filename)
             goto out;
         }
     }
+
 out:
+    if (ret < 0) {
+        error_setg_errno(errp, -ret, "Can't pre-allocate");
+    }
+out_with_err_set:
     if (bs) {
         bdrv_unref(bs);
     }
@@ -1636,7 +1646,6 @@ static int sd_create(const char *filename, QEMUOptionParameter *options,
     char tag[SD_MAX_VDI_TAG_LEN];
     uint32_t snapid;
     bool prealloc = false;
-    Error *local_err = NULL;
 
     s = g_malloc0(sizeof(BDRVSheepdogState));
 
@@ -1647,6 +1656,7 @@ static int sd_create(const char *filename, QEMUOptionParameter *options,
         ret = parse_vdiname(s, filename, s->name, &snapid, tag);
     }
     if (ret < 0) {
+        error_setg(errp, "Can't parse filename");
         goto out;
     }
 
@@ -1661,8 +1671,8 @@ static int sd_create(const char *filename, QEMUOptionParameter *options,
             } else if (!strcmp(options->value.s, "full")) {
                 prealloc = true;
             } else {
-                error_report("Invalid preallocation mode: '%s'",
-                             options->value.s);
+                error_setg(errp, "Invalid preallocation mode: '%s'",
+                           options->value.s);
                 ret = -EINVAL;
                 goto out;
             }
@@ -1670,6 +1680,8 @@ static int sd_create(const char *filename, QEMUOptionParameter *options,
             if (options->value.s) {
                 ret = parse_redundancy(s, options->value.s);
                 if (ret < 0) {
+                    error_setg(errp, "Invalid redundancy mode: '%s'",
+                               options->value.s);
                     goto out;
                 }
             }
@@ -1678,7 +1690,7 @@ static int sd_create(const char *filename, QEMUOptionParameter *options,
     }
 
     if (s->inode.vdi_size > SD_MAX_VDI_SIZE) {
-        error_report("too big image size");
+        error_setg(errp, "too big image size");
         ret = -EINVAL;
         goto out;
     }
@@ -1691,24 +1703,22 @@ static int sd_create(const char *filename, QEMUOptionParameter *options,
         /* Currently, only Sheepdog backing image is supported. */
         drv = bdrv_find_protocol(backing_file, true);
         if (!drv || strcmp(drv->protocol_name, "sheepdog") != 0) {
-            error_report("backing_file must be a sheepdog image");
+            error_setg(errp, "backing_file must be a sheepdog image");
             ret = -EINVAL;
             goto out;
         }
 
         bs = NULL;
         ret = bdrv_open(&bs, backing_file, NULL, NULL, BDRV_O_PROTOCOL, NULL,
-                        &local_err);
+                        errp);
         if (ret < 0) {
-            qerror_report_err(local_err);
-            error_free(local_err);
             goto out;
         }
 
         base = bs->opaque;
 
         if (!is_snapshot(&base->inode)) {
-            error_report("cannot clone from a non snapshot vdi");
+            error_setg(errp, "cannot clone from a non snapshot vdi");
             bdrv_unref(bs);
             ret = -EINVAL;
             goto out;
@@ -1717,12 +1727,14 @@ static int sd_create(const char *filename, QEMUOptionParameter *options,
         bdrv_unref(bs);
     }
 
-    ret = do_sd_create(s, &vid, 0);
-    if (!prealloc || ret) {
+    ret = do_sd_create(s, &vid, 0, errp);
+    if (ret) {
         goto out;
     }
 
-    ret = sd_prealloc(filename);
+    if (prealloc) {
+        ret = sd_prealloc(filename, errp);
+    }
 out:
     g_free(s);
     return ret;
@@ -1730,6 +1742,7 @@ out:
 
 static void sd_close(BlockDriverState *bs)
 {
+    Error *local_err = NULL;
     BDRVSheepdogState *s = bs->opaque;
     SheepdogVdiReq hdr;
     SheepdogVdiRsp *rsp = (SheepdogVdiRsp *)&hdr;
@@ -1738,8 +1751,10 @@ static void sd_close(BlockDriverState *bs)
 
     DPRINTF("%s\n", s->name);
 
-    fd = connect_to_sdog(s);
+    fd = connect_to_sdog(s, &local_err);
     if (fd < 0) {
+        error_report("%s", error_get_pretty(local_err));;
+        error_free(local_err);
         return;
     }
 
@@ -1774,6 +1789,7 @@ static int64_t sd_getlength(BlockDriverState *bs)
 
 static int sd_truncate(BlockDriverState *bs, int64_t offset)
 {
+    Error *local_err = NULL;
     BDRVSheepdogState *s = bs->opaque;
     int ret, fd;
     unsigned int datalen;
@@ -1786,8 +1802,10 @@ static int sd_truncate(BlockDriverState *bs, int64_t offset)
         return -EINVAL;
     }
 
-    fd = connect_to_sdog(s);
+    fd = connect_to_sdog(s, &local_err);
     if (fd < 0) {
+        error_report("%s", error_get_pretty(local_err));;
+        error_free(local_err);
         return fd;
     }
 
@@ -1846,6 +1864,7 @@ static void coroutine_fn sd_write_done(SheepdogAIOCB *acb)
 /* Delete current working VDI on the snapshot chain */
 static bool sd_delete(BDRVSheepdogState *s)
 {
+    Error *local_err = NULL;
     unsigned int wlen = SD_MAX_VDI_LEN, rlen = 0;
     SheepdogVdiReq hdr = {
         .opcode = SD_OP_DEL_VDI,
@@ -1856,8 +1875,10 @@ static bool sd_delete(BDRVSheepdogState *s)
     SheepdogVdiRsp *rsp = (SheepdogVdiRsp *)&hdr;
     int fd, ret;
 
-    fd = connect_to_sdog(s);
+    fd = connect_to_sdog(s, &local_err);
     if (fd < 0) {
+        error_report("%s", error_get_pretty(local_err));;
+        error_free(local_err);
         return false;
     }
 
@@ -1885,6 +1906,7 @@ static bool sd_delete(BDRVSheepdogState *s)
  */
 static int sd_create_branch(BDRVSheepdogState *s)
 {
+    Error *local_err = NULL;
     int ret, fd;
     uint32_t vid;
     char *buf;
@@ -1900,15 +1922,19 @@ static int sd_create_branch(BDRVSheepdogState *s)
      * false bail out.
      */
     deleted = sd_delete(s);
-    ret = do_sd_create(s, &vid, !deleted);
+    ret = do_sd_create(s, &vid, !deleted, &local_err);
     if (ret) {
+        error_report("%s", error_get_pretty(local_err));;
+        error_free(local_err);
         goto out;
     }
 
     DPRINTF("%" PRIx32 " is created.\n", vid);
 
-    fd = connect_to_sdog(s);
+    fd = connect_to_sdog(s, &local_err);
     if (fd < 0) {
+        error_report("%s", error_get_pretty(local_err));;
+        error_free(local_err);
         ret = fd;
         goto out;
     }
@@ -2122,6 +2148,7 @@ static int coroutine_fn sd_co_flush_to_disk(BlockDriverState *bs)
 
 static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
 {
+    Error *local_err = NULL;
     BDRVSheepdogState *s = bs->opaque;
     int ret, fd;
     uint32_t new_vid;
@@ -2151,8 +2178,10 @@ static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
     datalen = SD_INODE_SIZE - sizeof(s->inode.data_vdi_id);
 
     /* refresh inode. */
-    fd = connect_to_sdog(s);
+    fd = connect_to_sdog(s, &local_err);
     if (fd < 0) {
+        error_report("%s", error_get_pretty(local_err));;
+        error_free(local_err);
         ret = fd;
         goto cleanup;
     }
@@ -2164,8 +2193,10 @@ static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
         goto cleanup;
     }
 
-    ret = do_sd_create(s, &new_vid, 1);
+    ret = do_sd_create(s, &new_vid, 1, &local_err);
     if (ret < 0) {
+        error_report("%s", error_get_pretty(local_err));;
+        error_free(local_err);
         error_report("failed to create inode for snapshot. %s",
                      strerror(errno));
         goto cleanup;
@@ -2249,6 +2280,7 @@ static int sd_snapshot_delete(BlockDriverState *bs,
 
 static int sd_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
 {
+    Error *local_err = NULL;
     BDRVSheepdogState *s = bs->opaque;
     SheepdogReq req;
     int fd, nr = 1024, ret, max = BITS_TO_LONGS(SD_NR_VDIS) * sizeof(long);
@@ -2263,8 +2295,10 @@ static int sd_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
 
     vdi_inuse = g_malloc(max);
 
-    fd = connect_to_sdog(s);
+    fd = connect_to_sdog(s, &local_err);
     if (fd < 0) {
+        error_report("%s", error_get_pretty(local_err));;
+        error_free(local_err);
         ret = fd;
         goto out;
     }
@@ -2290,8 +2324,10 @@ static int sd_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab)
     hval = fnv_64a_buf(s->name, strlen(s->name), FNV1A_64_INIT);
     start_nr = hval & (SD_NR_VDIS - 1);
 
-    fd = connect_to_sdog(s);
+    fd = connect_to_sdog(s, &local_err);
     if (fd < 0) {
+        error_report("%s", error_get_pretty(local_err));;
+        error_free(local_err);
         ret = fd;
         goto out;
     }
@@ -2341,6 +2377,7 @@ out:
 static int do_load_save_vmstate(BDRVSheepdogState *s, uint8_t *data,
                                 int64_t pos, int size, int load)
 {
+    Error *local_err = NULL;
     bool create;
     int fd, ret = 0, remaining = size;
     unsigned int data_len;
@@ -2349,8 +2386,10 @@ static int do_load_save_vmstate(BDRVSheepdogState *s, uint8_t *data,
     uint32_t vdi_index;
     uint32_t vdi_id = load ? s->inode.parent_vdi_id : s->inode.vdi_id;
 
-    fd = connect_to_sdog(s);
+    fd = connect_to_sdog(s, &local_err);
     if (fd < 0) {
+        error_report("%s", error_get_pretty(local_err));;
+        error_free(local_err);
         return fd;
     }
 
diff --git a/block/ssh.c b/block/ssh.c
index aa63c9d20e..b2129714bc 100644
--- a/block/ssh.c
+++ b/block/ssh.c
@@ -106,30 +106,59 @@ static void ssh_state_free(BDRVSSHState *s)
     }
 }
 
-/* Wrappers around error_report which make sure to dump as much
- * information from libssh2 as possible.
- */
-static void GCC_FMT_ATTR(2, 3)
-session_error_report(BDRVSSHState *s, const char *fs, ...)
+static void GCC_FMT_ATTR(3, 4)
+session_error_setg(Error **errp, BDRVSSHState *s, const char *fs, ...)
 {
     va_list args;
+    char *msg;
 
     va_start(args, fs);
-    error_vprintf(fs, args);
+    msg = g_strdup_vprintf(fs, args);
+    va_end(args);
 
-    if ((s)->session) {
+    if (s->session) {
         char *ssh_err;
         int ssh_err_code;
 
-        libssh2_session_last_error((s)->session, &ssh_err, NULL, 0);
         /* This is not an errno.  See <libssh2.h>. */
-        ssh_err_code = libssh2_session_last_errno((s)->session);
-
-        error_printf(": %s (libssh2 error code: %d)", ssh_err, ssh_err_code);
+        ssh_err_code = libssh2_session_last_error(s->session,
+                                                  &ssh_err, NULL, 0);
+        error_setg(errp, "%s: %s (libssh2 error code: %d)",
+                   msg, ssh_err, ssh_err_code);
+    } else {
+        error_setg(errp, "%s", msg);
     }
+    g_free(msg);
+}
+
+static void GCC_FMT_ATTR(3, 4)
+sftp_error_setg(Error **errp, BDRVSSHState *s, const char *fs, ...)
+{
+    va_list args;
+    char *msg;
 
+    va_start(args, fs);
+    msg = g_strdup_vprintf(fs, args);
     va_end(args);
-    error_printf("\n");
+
+    if (s->sftp) {
+        char *ssh_err;
+        int ssh_err_code;
+        unsigned long sftp_err_code;
+
+        /* This is not an errno.  See <libssh2.h>. */
+        ssh_err_code = libssh2_session_last_error(s->session,
+                                                  &ssh_err, NULL, 0);
+        /* See <libssh2_sftp.h>. */
+        sftp_err_code = libssh2_sftp_last_error((s)->sftp);
+
+        error_setg(errp,
+                   "%s: %s (libssh2 error code: %d, sftp error code: %lu)",
+                   msg, ssh_err, ssh_err_code, sftp_err_code);
+    } else {
+        error_setg(errp, "%s", msg);
+    }
+    g_free(msg);
 }
 
 static void GCC_FMT_ATTR(2, 3)
@@ -145,9 +174,9 @@ sftp_error_report(BDRVSSHState *s, const char *fs, ...)
         int ssh_err_code;
         unsigned long sftp_err_code;
 
-        libssh2_session_last_error((s)->session, &ssh_err, NULL, 0);
         /* This is not an errno.  See <libssh2.h>. */
-        ssh_err_code = libssh2_session_last_errno((s)->session);
+        ssh_err_code = libssh2_session_last_error(s->session,
+                                                  &ssh_err, NULL, 0);
         /* See <libssh2_sftp.h>. */
         sftp_err_code = libssh2_sftp_last_error((s)->sftp);
 
@@ -243,7 +272,7 @@ static void ssh_parse_filename(const char *filename, QDict *options,
 }
 
 static int check_host_key_knownhosts(BDRVSSHState *s,
-                                     const char *host, int port)
+                                     const char *host, int port, Error **errp)
 {
     const char *home;
     char *knh_file = NULL;
@@ -257,14 +286,15 @@ static int check_host_key_knownhosts(BDRVSSHState *s,
     hostkey = libssh2_session_hostkey(s->session, &len, &type);
     if (!hostkey) {
         ret = -EINVAL;
-        session_error_report(s, "failed to read remote host key");
+        session_error_setg(errp, s, "failed to read remote host key");
         goto out;
     }
 
     knh = libssh2_knownhost_init(s->session);
     if (!knh) {
         ret = -EINVAL;
-        session_error_report(s, "failed to initialize known hosts support");
+        session_error_setg(errp, s,
+                           "failed to initialize known hosts support");
         goto out;
     }
 
@@ -289,21 +319,23 @@ static int check_host_key_knownhosts(BDRVSSHState *s,
         break;
     case LIBSSH2_KNOWNHOST_CHECK_MISMATCH:
         ret = -EINVAL;
-        session_error_report(s, "host key does not match the one in known_hosts (found key %s)",
-                             found->key);
+        session_error_setg(errp, s,
+                      "host key does not match the one in known_hosts"
+                      " (found key %s)", found->key);
         goto out;
     case LIBSSH2_KNOWNHOST_CHECK_NOTFOUND:
         ret = -EINVAL;
-        session_error_report(s, "no host key was found in known_hosts");
+        session_error_setg(errp, s, "no host key was found in known_hosts");
         goto out;
     case LIBSSH2_KNOWNHOST_CHECK_FAILURE:
         ret = -EINVAL;
-        session_error_report(s, "failure matching the host key with known_hosts");
+        session_error_setg(errp, s,
+                      "failure matching the host key with known_hosts");
         goto out;
     default:
         ret = -EINVAL;
-        session_error_report(s, "unknown error matching the host key with known_hosts (%d)",
-                             r);
+        session_error_setg(errp, s, "unknown error matching the host key"
+                      " with known_hosts (%d)", r);
         goto out;
     }
 
@@ -358,20 +390,20 @@ static int compare_fingerprint(const unsigned char *fingerprint, size_t len,
 
 static int
 check_host_key_hash(BDRVSSHState *s, const char *hash,
-                    int hash_type, size_t fingerprint_len)
+                    int hash_type, size_t fingerprint_len, Error **errp)
 {
     const char *fingerprint;
 
     fingerprint = libssh2_hostkey_hash(s->session, hash_type);
     if (!fingerprint) {
-        session_error_report(s, "failed to read remote host key");
+        session_error_setg(errp, s, "failed to read remote host key");
         return -EINVAL;
     }
 
     if(compare_fingerprint((unsigned char *) fingerprint, fingerprint_len,
                            hash) != 0) {
-        error_report("remote host key does not match host_key_check '%s'",
-                     hash);
+        error_setg(errp, "remote host key does not match host_key_check '%s'",
+                   hash);
         return -EPERM;
     }
 
@@ -379,7 +411,7 @@ check_host_key_hash(BDRVSSHState *s, const char *hash,
 }
 
 static int check_host_key(BDRVSSHState *s, const char *host, int port,
-                          const char *host_key_check)
+                          const char *host_key_check, Error **errp)
 {
     /* host_key_check=no */
     if (strcmp(host_key_check, "no") == 0) {
@@ -389,25 +421,25 @@ static int check_host_key(BDRVSSHState *s, const char *host, int port,
     /* host_key_check=md5:xx:yy:zz:... */
     if (strncmp(host_key_check, "md5:", 4) == 0) {
         return check_host_key_hash(s, &host_key_check[4],
-                                   LIBSSH2_HOSTKEY_HASH_MD5, 16);
+                                   LIBSSH2_HOSTKEY_HASH_MD5, 16, errp);
     }
 
     /* host_key_check=sha1:xx:yy:zz:... */
     if (strncmp(host_key_check, "sha1:", 5) == 0) {
         return check_host_key_hash(s, &host_key_check[5],
-                                   LIBSSH2_HOSTKEY_HASH_SHA1, 20);
+                                   LIBSSH2_HOSTKEY_HASH_SHA1, 20, errp);
     }
 
     /* host_key_check=yes */
     if (strcmp(host_key_check, "yes") == 0) {
-        return check_host_key_knownhosts(s, host, port);
+        return check_host_key_knownhosts(s, host, port, errp);
     }
 
-    error_report("unknown host_key_check setting (%s)", host_key_check);
+    error_setg(errp, "unknown host_key_check setting (%s)", host_key_check);
     return -EINVAL;
 }
 
-static int authenticate(BDRVSSHState *s, const char *user)
+static int authenticate(BDRVSSHState *s, const char *user, Error **errp)
 {
     int r, ret;
     const char *userauthlist;
@@ -418,7 +450,8 @@ static int authenticate(BDRVSSHState *s, const char *user)
     userauthlist = libssh2_userauth_list(s->session, user, strlen(user));
     if (strstr(userauthlist, "publickey") == NULL) {
         ret = -EPERM;
-        error_report("remote server does not support \"publickey\" authentication");
+        error_setg(errp,
+                "remote server does not support \"publickey\" authentication");
         goto out;
     }
 
@@ -426,17 +459,18 @@ static int authenticate(BDRVSSHState *s, const char *user)
     agent = libssh2_agent_init(s->session);
     if (!agent) {
         ret = -EINVAL;
-        session_error_report(s, "failed to initialize ssh-agent support");
+        session_error_setg(errp, s, "failed to initialize ssh-agent support");
         goto out;
     }
     if (libssh2_agent_connect(agent)) {
         ret = -ECONNREFUSED;
-        session_error_report(s, "failed to connect to ssh-agent");
+        session_error_setg(errp, s, "failed to connect to ssh-agent");
         goto out;
     }
     if (libssh2_agent_list_identities(agent)) {
         ret = -EINVAL;
-        session_error_report(s, "failed requesting identities from ssh-agent");
+        session_error_setg(errp, s,
+                           "failed requesting identities from ssh-agent");
         goto out;
     }
 
@@ -447,7 +481,8 @@ static int authenticate(BDRVSSHState *s, const char *user)
         }
         if (r < 0) {
             ret = -EINVAL;
-            session_error_report(s, "failed to obtain identity from ssh-agent");
+            session_error_setg(errp, s,
+                               "failed to obtain identity from ssh-agent");
             goto out;
         }
         r = libssh2_agent_userauth(agent, user, identity);
@@ -461,8 +496,8 @@ static int authenticate(BDRVSSHState *s, const char *user)
     }
 
     ret = -EPERM;
-    error_report("failed to authenticate using publickey authentication "
-                 "and the identities held by your ssh-agent");
+    error_setg(errp, "failed to authenticate using publickey authentication "
+               "and the identities held by your ssh-agent");
 
  out:
     if (agent != NULL) {
@@ -476,10 +511,9 @@ static int authenticate(BDRVSSHState *s, const char *user)
 }
 
 static int connect_to_ssh(BDRVSSHState *s, QDict *options,
-                          int ssh_flags, int creat_mode)
+                          int ssh_flags, int creat_mode, Error **errp)
 {
     int r, ret;
-    Error *err = NULL;
     const char *host, *user, *path, *host_key_check;
     int port;
 
@@ -498,6 +532,7 @@ static int connect_to_ssh(BDRVSSHState *s, QDict *options,
     } else {
         user = g_get_user_name();
         if (!user) {
+            error_setg_errno(errp, errno, "Can't get user name");
             ret = -errno;
             goto err;
         }
@@ -514,11 +549,9 @@ static int connect_to_ssh(BDRVSSHState *s, QDict *options,
     s->hostport = g_strdup_printf("%s:%d", host, port);
 
     /* Open the socket and connect. */
-    s->sock = inet_connect(s->hostport, &err);
-    if (err != NULL) {
+    s->sock = inet_connect(s->hostport, errp);
+    if (s->sock < 0) {
         ret = -errno;
-        qerror_report_err(err);
-        error_free(err);
         goto err;
     }
 
@@ -526,7 +559,7 @@ static int connect_to_ssh(BDRVSSHState *s, QDict *options,
     s->session = libssh2_session_init();
     if (!s->session) {
         ret = -EINVAL;
-        session_error_report(s, "failed to initialize libssh2 session");
+        session_error_setg(errp, s, "failed to initialize libssh2 session");
         goto err;
     }
 
@@ -537,18 +570,18 @@ static int connect_to_ssh(BDRVSSHState *s, QDict *options,
     r = libssh2_session_handshake(s->session, s->sock);
     if (r != 0) {
         ret = -EINVAL;
-        session_error_report(s, "failed to establish SSH session");
+        session_error_setg(errp, s, "failed to establish SSH session");
         goto err;
     }
 
     /* Check the remote host's key against known_hosts. */
-    ret = check_host_key(s, host, port, host_key_check);
+    ret = check_host_key(s, host, port, host_key_check, errp);
     if (ret < 0) {
         goto err;
     }
 
     /* Authenticate. */
-    ret = authenticate(s, user);
+    ret = authenticate(s, user, errp);
     if (ret < 0) {
         goto err;
     }
@@ -556,7 +589,7 @@ static int connect_to_ssh(BDRVSSHState *s, QDict *options,
     /* Start SFTP. */
     s->sftp = libssh2_sftp_init(s->session);
     if (!s->sftp) {
-        session_error_report(s, "failed to initialize sftp handle");
+        session_error_setg(errp, s, "failed to initialize sftp handle");
         ret = -EINVAL;
         goto err;
     }
@@ -566,14 +599,14 @@ static int connect_to_ssh(BDRVSSHState *s, QDict *options,
             path, ssh_flags, creat_mode);
     s->sftp_handle = libssh2_sftp_open(s->sftp, path, ssh_flags, creat_mode);
     if (!s->sftp_handle) {
-        session_error_report(s, "failed to open remote file '%s'", path);
+        session_error_setg(errp, s, "failed to open remote file '%s'", path);
         ret = -EINVAL;
         goto err;
     }
 
     r = libssh2_sftp_fstat(s->sftp_handle, &s->attrs);
     if (r < 0) {
-        sftp_error_report(s, "failed to read file attributes");
+        sftp_error_setg(errp, s, "failed to read file attributes");
         return -EINVAL;
     }
 
@@ -623,7 +656,7 @@ static int ssh_file_open(BlockDriverState *bs, QDict *options, int bdrv_flags,
     }
 
     /* Start up SSH. */
-    ret = connect_to_ssh(s, options, ssh_flags, 0);
+    ret = connect_to_ssh(s, options, ssh_flags, 0, errp);
     if (ret < 0) {
         goto err;
     }
@@ -655,7 +688,6 @@ static int ssh_create(const char *filename, QEMUOptionParameter *options,
                       Error **errp)
 {
     int r, ret;
-    Error *local_err = NULL;
     int64_t total_size = 0;
     QDict *uri_options = NULL;
     BDRVSSHState s;
@@ -674,17 +706,16 @@ static int ssh_create(const char *filename, QEMUOptionParameter *options,
     DPRINTF("total_size=%" PRIi64, total_size);
 
     uri_options = qdict_new();
-    r = parse_uri(filename, uri_options, &local_err);
+    r = parse_uri(filename, uri_options, errp);
     if (r < 0) {
-        qerror_report_err(local_err);
-        error_free(local_err);
         ret = r;
         goto out;
     }
 
     r = connect_to_ssh(&s, uri_options,
                        LIBSSH2_FXF_READ|LIBSSH2_FXF_WRITE|
-                       LIBSSH2_FXF_CREAT|LIBSSH2_FXF_TRUNC, 0644);
+                       LIBSSH2_FXF_CREAT|LIBSSH2_FXF_TRUNC,
+                       0644, errp);
     if (r < 0) {
         ret = r;
         goto out;
@@ -694,7 +725,7 @@ static int ssh_create(const char *filename, QEMUOptionParameter *options,
         libssh2_sftp_seek64(s.sftp_handle, total_size-1);
         r2 = libssh2_sftp_write(s.sftp_handle, c, 1);
         if (r2 < 0) {
-            sftp_error_report(&s, "truncate failed");
+            sftp_error_setg(errp, &s, "truncate failed");
             ret = -EINVAL;
             goto out;
         }
diff --git a/block/stream.c b/block/stream.c
index dd0b4ac3d2..91d18a2db7 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -60,7 +60,7 @@ static void close_unused_images(BlockDriverState *top, BlockDriverState *base,
     /* Must assign before bdrv_delete() to prevent traversing dangling pointer
      * while we delete backing image instances.
      */
-    top->backing_hd = base;
+    bdrv_set_backing_hd(top, base);
 
     while (intermediate) {
         BlockDriverState *unused;
@@ -72,7 +72,7 @@ static void close_unused_images(BlockDriverState *top, BlockDriverState *base,
 
         unused = intermediate;
         intermediate = intermediate->backing_hd;
-        unused->backing_hd = NULL;
+        bdrv_set_backing_hd(unused, NULL);
         bdrv_unref(unused);
     }
 
diff --git a/block/vvfat.c b/block/vvfat.c
index c3af7ff4c5..8f5114bd16 100644
--- a/block/vvfat.c
+++ b/block/vvfat.c
@@ -831,7 +831,8 @@ static inline off_t cluster2sector(BDRVVVFATState* s, uint32_t cluster_num)
 }
 
 static int init_directories(BDRVVVFATState* s,
-                            const char *dirname, int heads, int secs)
+                            const char *dirname, int heads, int secs,
+                            Error **errp)
 {
     bootsector_t* bootsector;
     mapping_t* mapping;
@@ -892,8 +893,8 @@ static int init_directories(BDRVVVFATState* s,
         if (mapping->mode & MODE_DIRECTORY) {
 	    mapping->begin = cluster;
 	    if(read_directory(s, i)) {
-		fprintf(stderr, "Could not read directory %s\n",
-			mapping->path);
+                error_setg(errp, "Could not read directory %s",
+                           mapping->path);
 		return -1;
 	    }
 	    mapping = array_get(&(s->mapping), i);
@@ -919,9 +920,10 @@ static int init_directories(BDRVVVFATState* s,
 	cluster = mapping->end;
 
 	if(cluster > s->cluster_count) {
-	    fprintf(stderr,"Directory does not fit in FAT%d (capacity %.2f MB)\n",
-		    s->fat_type, s->sector_count / 2000.0);
-	    return -EINVAL;
+            error_setg(errp,
+                       "Directory does not fit in FAT%d (capacity %.2f MB)",
+                       s->fat_type, s->sector_count / 2000.0);
+            return -1;
 	}
 
 	/* fix fat for entry */
@@ -979,7 +981,7 @@ static int init_directories(BDRVVVFATState* s,
 static BDRVVVFATState *vvv = NULL;
 #endif
 
-static int enable_write_target(BDRVVVFATState *s);
+static int enable_write_target(BDRVVVFATState *s, Error **errp);
 static int is_consistent(BDRVVVFATState *s);
 
 static void vvfat_rebind(BlockDriverState *bs)
@@ -1160,7 +1162,7 @@ DLOG(if (stderr == NULL) {
     s->sector_count = cyls * heads * secs - (s->first_sectors_number - 1);
 
     if (qemu_opt_get_bool(opts, "rw", false)) {
-        ret = enable_write_target(s);
+        ret = enable_write_target(s, errp);
         if (ret < 0) {
             goto fail;
         }
@@ -1169,7 +1171,7 @@ DLOG(if (stderr == NULL) {
 
     bs->total_sectors = cyls * heads * secs;
 
-    if (init_directories(s, dirname, heads, secs)) {
+    if (init_directories(s, dirname, heads, secs, errp)) {
         ret = -EIO;
         goto fail;
     }
@@ -2904,11 +2906,10 @@ static BlockDriver vvfat_write_target = {
     .bdrv_close         = write_target_close,
 };
 
-static int enable_write_target(BDRVVVFATState *s)
+static int enable_write_target(BDRVVVFATState *s, Error **errp)
 {
     BlockDriver *bdrv_qcow;
     QEMUOptionParameter *options;
-    Error *local_err = NULL;
     int ret;
     int size = sector2cluster(s, s->sector_count);
     s->used_clusters = calloc(size, 1);
@@ -2918,6 +2919,7 @@ static int enable_write_target(BDRVVVFATState *s)
     s->qcow_filename = g_malloc(1024);
     ret = get_tmp_filename(s->qcow_filename, 1024);
     if (ret < 0) {
+        error_setg_errno(errp, -ret, "can't create temporary file");
         goto err;
     }
 
@@ -2926,20 +2928,16 @@ static int enable_write_target(BDRVVVFATState *s)
     set_option_parameter_int(options, BLOCK_OPT_SIZE, s->sector_count * 512);
     set_option_parameter(options, BLOCK_OPT_BACKING_FILE, "fat:");
 
-    ret = bdrv_create(bdrv_qcow, s->qcow_filename, options, &local_err);
+    ret = bdrv_create(bdrv_qcow, s->qcow_filename, options, errp);
     if (ret < 0) {
-        qerror_report_err(local_err);
-        error_free(local_err);
         goto err;
     }
 
     s->qcow = NULL;
     ret = bdrv_open(&s->qcow, s->qcow_filename, NULL, NULL,
-            BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH, bdrv_qcow,
-            &local_err);
+                    BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_NO_FLUSH,
+                    bdrv_qcow, errp);
     if (ret < 0) {
-        qerror_report_err(local_err);
-        error_free(local_err);
         goto err;
     }
 
@@ -2947,7 +2945,7 @@ static int enable_write_target(BDRVVVFATState *s)
     unlink(s->qcow_filename);
 #endif
 
-    s->bs->backing_hd = bdrv_new("", &error_abort);
+    bdrv_set_backing_hd(s->bs, bdrv_new("", &error_abort));
     s->bs->backing_hd->drv = &vvfat_write_target;
     s->bs->backing_hd->opaque = g_malloc(sizeof(void*));
     *(void**)s->bs->backing_hd->opaque = s;
diff --git a/blockdev.c b/blockdev.c
index 1cbcc1c785..8cc42fb1d0 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -34,7 +34,6 @@
 #include "hw/block/block.h"
 #include "block/blockjob.h"
 #include "monitor/monitor.h"
-#include "qapi/qmp/qerror.h"
 #include "qemu/option.h"
 #include "qemu/config-file.h"
 #include "qapi/qmp/types.h"
@@ -730,7 +729,7 @@ DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)
                                    &error_abort);
     qemu_opts_absorb_qdict(legacy_opts, bs_opts, &local_err);
     if (local_err) {
-        qerror_report_err(local_err);
+        error_report("%s", error_get_pretty(local_err));
         error_free(local_err);
         goto fail;
     }
@@ -942,7 +941,7 @@ DriveInfo *drive_init(QemuOpts *all_opts, BlockInterfaceType block_default_type)
     dinfo = blockdev_init(filename, bs_opts, &local_err);
     if (dinfo == NULL) {
         if (local_err) {
-            qerror_report_err(local_err);
+            error_report("%s", error_get_pretty(local_err));
             error_free(local_err);
         }
         goto fail;
@@ -1334,8 +1333,8 @@ static void external_snapshot_prepare(BlkTransactionState *common,
         return;
     }
 
-    if (bdrv_in_use(state->old_bs)) {
-        error_set(errp, QERR_DEVICE_IN_USE, device);
+    if (bdrv_op_is_blocked(state->old_bs,
+                           BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT, errp)) {
         return;
     }
 
@@ -1557,8 +1556,7 @@ exit:
 
 static void eject_device(BlockDriverState *bs, int force, Error **errp)
 {
-    if (bdrv_in_use(bs)) {
-        error_set(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_EJECT, errp)) {
         return;
     }
     if (!bdrv_dev_has_removable_media(bs)) {
@@ -1760,14 +1758,16 @@ int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
 {
     const char *id = qdict_get_str(qdict, "id");
     BlockDriverState *bs;
+    Error *local_err = NULL;
 
     bs = bdrv_find(id);
     if (!bs) {
-        qerror_report(QERR_DEVICE_NOT_FOUND, id);
+        error_report("Device '%s' not found", id);
         return -1;
     }
-    if (bdrv_in_use(bs)) {
-        qerror_report(QERR_DEVICE_IN_USE, id);
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_DRIVE_DEL, &local_err)) {
+        error_report("%s", error_get_pretty(local_err));
+        error_free(local_err);
         return -1;
     }
 
@@ -1888,6 +1888,10 @@ void qmp_block_stream(const char *device, bool has_base,
         return;
     }
 
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_STREAM, errp)) {
+        return;
+    }
+
     if (base) {
         base_bs = bdrv_find_backing_image(bs, base);
         if (base_bs == NULL) {
@@ -1932,6 +1936,10 @@ void qmp_block_commit(const char *device,
         return;
     }
 
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT, errp)) {
+        return;
+    }
+
     /* default top_bs is the active layer */
     top_bs = bs;
 
@@ -2023,8 +2031,7 @@ void qmp_drive_backup(const char *device, const char *target,
         }
     }
 
-    if (bdrv_in_use(bs)) {
-        error_set(errp, QERR_DEVICE_IN_USE, device);
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
         return;
     }
 
@@ -2157,8 +2164,7 @@ void qmp_drive_mirror(const char *device, const char *target,
         }
     }
 
-    if (bdrv_in_use(bs)) {
-        error_set(errp, QERR_DEVICE_IN_USE, device);
+    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_MIRROR, errp)) {
         return;
     }
 
diff --git a/blockjob.c b/blockjob.c
index cd4784f053..7d84ca1d6c 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -41,14 +41,16 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
 {
     BlockJob *job;
 
-    if (bs->job || bdrv_in_use(bs)) {
+    if (bs->job) {
         error_set(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
         return NULL;
     }
     bdrv_ref(bs);
-    bdrv_set_in_use(bs, 1);
-
     job = g_malloc0(driver->instance_size);
+    error_setg(&job->blocker, "block device is in use by block job: %s",
+               BlockJobType_lookup[driver->job_type]);
+    bdrv_op_block_all(bs, job->blocker);
+
     job->driver        = driver;
     job->bs            = bs;
     job->cb            = cb;
@@ -63,8 +65,9 @@ void *block_job_create(const BlockJobDriver *driver, BlockDriverState *bs,
         block_job_set_speed(job, speed, &local_err);
         if (local_err) {
             bs->job = NULL;
+            bdrv_op_unblock_all(bs, job->blocker);
+            error_free(job->blocker);
             g_free(job);
-            bdrv_set_in_use(bs, 0);
             error_propagate(errp, local_err);
             return NULL;
         }
@@ -79,8 +82,9 @@ void block_job_completed(BlockJob *job, int ret)
     assert(bs->job == job);
     job->cb(job->opaque, ret);
     bs->job = NULL;
+    bdrv_op_unblock_all(bs, job->blocker);
+    error_free(job->blocker);
     g_free(job);
-    bdrv_set_in_use(bs, 0);
 }
 
 void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt
index f19536a46f..3f713a6447 100644
--- a/docs/specs/qcow2.txt
+++ b/docs/specs/qcow2.txt
@@ -107,8 +107,9 @@ in the description of a field.
 
          96 -  99:  refcount_order
                     Describes the width of a reference count block entry (width
-                    in bits = 1 << refcount_order). For version 2 images, the
-                    order is always assumed to be 4 (i.e. the width is 16 bits).
+                    in bits: refcount_bits = 1 << refcount_order). For version 2
+                    images, the order is always assumed to be 4
+                    (i.e. refcount_bits = 16).
 
         100 - 103:  header_length
                     Length of the header structure in bytes. For version 2
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 70b8a5ab75..e49c2536b1 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -70,6 +70,9 @@ struct VirtIOBlockDataPlane {
                                              queue */
 
     unsigned int num_reqs;
+
+    /* Operation blocker on BDS */
+    Error *blocker;
 };
 
 /* Raise an interrupt to signal guest, if necessary */
@@ -350,6 +353,7 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *blk,
 {
     VirtIOBlockDataPlane *s;
     int fd;
+    Error *local_err = NULL;
 
     *dataplane = NULL;
 
@@ -372,9 +376,10 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *blk,
     /* If dataplane is (re-)enabled while the guest is running there could be
      * block jobs that can conflict.
      */
-    if (bdrv_in_use(blk->conf.bs)) {
-        error_setg(errp,
-                   "cannot start dataplane thread while device is in use");
+    if (bdrv_op_is_blocked(blk->conf.bs, BLOCK_OP_TYPE_DATAPLANE, &local_err)) {
+        error_report("cannot start dataplane thread: %s",
+                      error_get_pretty(local_err));
+        error_free(local_err);
         return;
     }
 
@@ -406,8 +411,8 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *blk,
     }
     s->ctx = iothread_get_aio_context(s->iothread);
 
-    /* Prevent block operations that conflict with data plane thread */
-    bdrv_set_in_use(blk->conf.bs, 1);
+    error_setg(&s->blocker, "block device is in use by data plane");
+    bdrv_op_block_all(blk->conf.bs, s->blocker);
 
     *dataplane = s;
 }
@@ -420,7 +425,8 @@ void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane *s)
     }
 
     virtio_blk_data_plane_stop(s);
-    bdrv_set_in_use(s->blk->conf.bs, 0);
+    bdrv_op_unblock_all(s->blk->conf.bs, s->blocker);
+    error_free(s->blocker);
     object_unref(OBJECT(s->iothread));
     g_free(s);
 }
diff --git a/include/block/block.h b/include/block/block.h
index 59be83f3c2..faee3aa246 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -162,6 +162,25 @@ typedef struct BDRVReopenState {
     void *opaque;
 } BDRVReopenState;
 
+/*
+ * Block operation types
+ */
+typedef enum BlockOpType {
+    BLOCK_OP_TYPE_BACKUP_SOURCE,
+    BLOCK_OP_TYPE_BACKUP_TARGET,
+    BLOCK_OP_TYPE_CHANGE,
+    BLOCK_OP_TYPE_COMMIT,
+    BLOCK_OP_TYPE_DATAPLANE,
+    BLOCK_OP_TYPE_DRIVE_DEL,
+    BLOCK_OP_TYPE_EJECT,
+    BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT,
+    BLOCK_OP_TYPE_INTERNAL_SNAPSHOT,
+    BLOCK_OP_TYPE_INTERNAL_SNAPSHOT_DELETE,
+    BLOCK_OP_TYPE_MIRROR,
+    BLOCK_OP_TYPE_RESIZE,
+    BLOCK_OP_TYPE_STREAM,
+    BLOCK_OP_TYPE_MAX,
+} BlockOpType;
 
 void bdrv_iostatus_enable(BlockDriverState *bs);
 void bdrv_iostatus_reset(BlockDriverState *bs);
@@ -197,6 +216,7 @@ int bdrv_parse_discard_flags(const char *mode, int *flags);
 int bdrv_open_image(BlockDriverState **pbs, const char *filename,
                     QDict *options, const char *bdref_key, int flags,
                     bool allow_none, Error **errp);
+void bdrv_set_backing_hd(BlockDriverState *bs, BlockDriverState *backing_hd);
 int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp);
 void bdrv_append_temp_snapshot(BlockDriverState *bs, int flags, Error **errp);
 int bdrv_open(BlockDriverState **pbs, const char *filename,
@@ -453,8 +473,13 @@ void bdrv_disable_copy_on_read(BlockDriverState *bs);
 
 void bdrv_ref(BlockDriverState *bs);
 void bdrv_unref(BlockDriverState *bs);
-void bdrv_set_in_use(BlockDriverState *bs, int in_use);
-int bdrv_in_use(BlockDriverState *bs);
+
+bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
+void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
+void bdrv_op_unblock(BlockDriverState *bs, BlockOpType op, Error *reason);
+void bdrv_op_block_all(BlockDriverState *bs, Error *reason);
+void bdrv_op_unblock_all(BlockDriverState *bs, Error *reason);
+bool bdrv_op_blocker_is_empty(BlockDriverState *bs);
 
 #ifdef CONFIG_LINUX_AIO
 int raw_get_aio_fd(BlockDriverState *bs);
diff --git a/include/block/block_int.h b/include/block/block_int.h
index b8cc926bfe..f2e753f632 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -270,6 +270,8 @@ typedef struct BlockLimits {
     size_t opt_mem_alignment;
 } BlockLimits;
 
+typedef struct BdrvOpBlocker BdrvOpBlocker;
+
 /*
  * Note: the function bdrv_append() copies and swaps contents of
  * BlockDriverStates, so if you add new fields to this struct, please
@@ -356,15 +358,20 @@ struct BlockDriverState {
     QTAILQ_ENTRY(BlockDriverState) device_list;
     QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps;
     int refcnt;
-    int in_use; /* users other than guest access, eg. block migration */
 
     QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
 
+    /* operation blockers */
+    QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX];
+
     /* long-running background operation */
     BlockJob *job;
 
     QDict *options;
     BlockdevDetectZeroesOptions detect_zeroes;
+
+    /* The error object in use for blocking operations on backing_hd */
+    Error *backing_blocker;
 };
 
 int get_tmp_filename(char *filename, int size);
diff --git a/include/block/blockjob.h b/include/block/blockjob.h
index d76de62a46..c0a787530b 100644
--- a/include/block/blockjob.h
+++ b/include/block/blockjob.h
@@ -106,6 +106,9 @@ struct BlockJob {
     /** The completion function that will be called when the job completes.  */
     BlockDriverCompletionFunc *cb;
 
+    /** Block other operations when block job is running */
+    Error *blocker;
+
     /** The opaque value that is passed to the completion function.  */
     void *opaque;
 };
diff --git a/qemu-nbd.c b/qemu-nbd.c
index cd6bd50fae..ba6043680a 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -223,7 +223,7 @@ static int tcp_socket_incoming(const char *address, uint16_t port)
     int fd = inet_listen(address_and_port, NULL, 0, SOCK_STREAM, 0, &local_err);
 
     if (local_err != NULL) {
-        qerror_report_err(local_err);
+        error_report("%s", error_get_pretty(local_err));
         error_free(local_err);
     }
     return fd;
@@ -235,7 +235,7 @@ static int unix_socket_incoming(const char *path)
     int fd = unix_listen(path, NULL, 0, &local_err);
 
     if (local_err != NULL) {
-        qerror_report_err(local_err);
+        error_report("%s", error_get_pretty(local_err));
         error_free(local_err);
     }
     return fd;
@@ -247,7 +247,7 @@ static int unix_socket_outgoing(const char *path)
     int fd = unix_connect(path, &local_err);
 
     if (local_err != NULL) {
-        qerror_report_err(local_err);
+        error_report("%s", error_get_pretty(local_err));
         error_free(local_err);
     }
     return fd;
diff --git a/tests/Makefile b/tests/Makefile
index 9f7ca61ae3..8f71e0d664 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -60,6 +60,8 @@ check-unit-y += tests/test-qdev-global-props$(EXESUF)
 check-unit-y += tests/check-qom-interface$(EXESUF)
 gcov-files-check-qom-interface-y = qom/object.c
 check-unit-$(CONFIG_POSIX) += tests/test-vmstate$(EXESUF)
+check-unit-y += tests/test-qemu-opts$(EXESUF)
+gcov-files-test-qemu-opts-y = qom/test-qemu-opts.c
 
 check-block-$(CONFIG_POSIX) += tests/qemu-iotests-quick.sh
 
@@ -319,6 +321,7 @@ tests/intel-hda-test$(EXESUF): tests/intel-hda-test.o
 tests/ioh3420-test$(EXESUF): tests/ioh3420-test.o
 tests/usb-hcd-ehci-test$(EXESUF): tests/usb-hcd-ehci-test.o
 tests/qemu-iotests/socket_scm_helper$(EXESUF): tests/qemu-iotests/socket_scm_helper.o
+tests/test-qemu-opts$(EXESUF): tests/test-qemu-opts.o libqemuutil.a libqemustub.a
 
 # QTest rules
 
diff --git a/tests/qemu-iotests/089 b/tests/qemu-iotests/089
index ef476010c0..dffc977e1c 100755
--- a/tests/qemu-iotests/089
+++ b/tests/qemu-iotests/089
@@ -107,8 +107,7 @@ echo
 echo "=== Testing qemu-img info output ==="
 echo
 
-$QEMU_IMG info "json:{\"driver\":\"qcow2\",\"file.filename\":\"$TEST_IMG\"}" \
-    | _filter_testdir | _filter_imgfmt
+TEST_IMG="json:{\"driver\":\"qcow2\",\"file.filename\":\"$TEST_IMG\"}" _img_info
 
 
 echo
diff --git a/tests/qemu-iotests/089.out b/tests/qemu-iotests/089.out
index d6cf7835d8..4ca2f88e6a 100644
--- a/tests/qemu-iotests/089.out
+++ b/tests/qemu-iotests/089.out
@@ -31,11 +31,7 @@ read failed: Input/output error
 image: TEST_DIR/t.IMGFMT
 file format: IMGFMT
 virtual size: 64M (67108864 bytes)
-disk size: 324K
 cluster_size: 65536
-Format specific information:
-    compat: 1.1
-    lazy refcounts: false
 
 === Testing option merging ===
 
diff --git a/tests/qemu-iotests/091 b/tests/qemu-iotests/091
index 384b3ace54..32bbd56975 100755
--- a/tests/qemu-iotests/091
+++ b/tests/qemu-iotests/091
@@ -47,6 +47,8 @@ trap "_cleanup; exit \$status" 0 1 2 3 15
 _supported_fmt qcow2
 _supported_proto file
 _supported_os Linux
+_default_cache_mode "none"
+_supported_cache_modes "writethrough" "none" "writeback"
 
 size=1G
 
@@ -59,13 +61,13 @@ echo === Starting QEMU VM1 ===
 echo
 
 qemu_comm_method="monitor"
-_launch_qemu -drive file="${TEST_IMG}",cache=none,id=disk
+_launch_qemu -drive file="${TEST_IMG}",cache=${CACHEMODE},id=disk
 h1=$QEMU_HANDLE
 
 echo
 echo === Starting QEMU VM2 ===
 echo
-_launch_qemu -drive file="${TEST_IMG}",cache=none,id=disk \
+_launch_qemu -drive file="${TEST_IMG}",cache=${CACHEMODE},id=disk \
              -incoming "exec: cat '${MIG_FIFO}'"
 h2=$QEMU_HANDLE
 
diff --git a/tests/test-qemu-opts.c b/tests/test-qemu-opts.c
new file mode 100644
index 0000000000..3653507f56
--- /dev/null
+++ b/tests/test-qemu-opts.c
@@ -0,0 +1,441 @@
+/*
+ * QemuOpts unit-tests.
+ *
+ * Copyright (C) 2014 Leandro Dorileo <l@dorileo.org>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ */
+
+#include "qapi/error.h"
+#include "qapi/qmp/qstring.h"
+#include "qemu/config-file.h"
+
+#include <glib.h>
+#include <string.h>
+
+static QemuOptsList opts_list_01 = {
+    .name = "opts_list_01",
+    .head = QTAILQ_HEAD_INITIALIZER(opts_list_01.head),
+    .desc = {
+        {
+            .name = "str1",
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "str2",
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "str3",
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "number1",
+            .type = QEMU_OPT_NUMBER,
+        },
+        { /* end of list */ }
+    },
+};
+
+static QemuOptsList opts_list_02 = {
+    .name = "opts_list_02",
+    .head = QTAILQ_HEAD_INITIALIZER(opts_list_02.head),
+    .desc = {
+        {
+            .name = "str1",
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "bool1",
+            .type = QEMU_OPT_BOOL,
+        },{
+            .name = "str2",
+            .type = QEMU_OPT_STRING,
+        },{
+            .name = "size1",
+            .type = QEMU_OPT_SIZE,
+        },
+        { /* end of list */ }
+    },
+};
+
+QemuOptsList opts_list_03 = {
+    .name = "opts_list_03",
+    .head = QTAILQ_HEAD_INITIALIZER(opts_list_03.head),
+    .desc = {
+        /* no elements => accept any params */
+        { /* end of list */ }
+    },
+};
+
+static void register_opts(void)
+{
+    qemu_add_opts(&opts_list_01);
+    qemu_add_opts(&opts_list_02);
+    qemu_add_opts(&opts_list_03);
+}
+
+static void test_find_unknown_opts(void)
+{
+    QemuOptsList *list;
+    Error *err = NULL;
+
+    /* should not return anything, we don't have an "unknown" option */
+    list = qemu_find_opts_err("unknown", &err);
+    g_assert(list == NULL);
+    g_assert(err);
+    error_free(err);
+}
+
+static void test_qemu_find_opts(void)
+{
+    QemuOptsList *list;
+
+    /* we have an "opts_list_01" option, should return it */
+    list = qemu_find_opts("opts_list_01");
+    g_assert(list != NULL);
+    g_assert_cmpstr(list->name, ==, "opts_list_01");
+}
+
+static void test_qemu_opts_create(void)
+{
+    QemuOptsList *list;
+    QemuOpts *opts;
+
+    list = qemu_find_opts("opts_list_01");
+    g_assert(list != NULL);
+    g_assert(QTAILQ_EMPTY(&list->head));
+    g_assert_cmpstr(list->name, ==, "opts_list_01");
+
+    /* should not find anything at this point */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts == NULL);
+
+    /* create the opts */
+    opts = qemu_opts_create(list, NULL, 0, &error_abort);
+    g_assert(opts != NULL);
+    g_assert(!QTAILQ_EMPTY(&list->head));
+
+    /* now we've create the opts, must find it */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts != NULL);
+
+    qemu_opts_del(opts);
+
+    /* should not find anything at this point */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts == NULL);
+}
+
+static void test_qemu_opt_get(void)
+{
+    QemuOptsList *list;
+    QemuOpts *opts;
+    const char *opt = NULL;
+
+    list = qemu_find_opts("opts_list_01");
+    g_assert(list != NULL);
+    g_assert(QTAILQ_EMPTY(&list->head));
+    g_assert_cmpstr(list->name, ==, "opts_list_01");
+
+    /* should not find anything at this point */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts == NULL);
+
+    /* create the opts */
+    opts = qemu_opts_create(list, NULL, 0, &error_abort);
+    g_assert(opts != NULL);
+    g_assert(!QTAILQ_EMPTY(&list->head));
+
+    /* haven't set anything to str2 yet */
+    opt = qemu_opt_get(opts, "str2");
+    g_assert(opt == NULL);
+
+    qemu_opt_set(opts, "str2", "value");
+
+    /* now we have set str2, should know about it */
+    opt = qemu_opt_get(opts, "str2");
+    g_assert_cmpstr(opt, ==, "value");
+
+    qemu_opt_set(opts, "str2", "value2");
+
+    /* having reset the value, the returned should be the reset one */
+    opt = qemu_opt_get(opts, "str2");
+    g_assert_cmpstr(opt, ==, "value2");
+
+    qemu_opts_del(opts);
+
+    /* should not find anything at this point */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts == NULL);
+}
+
+static void test_qemu_opt_get_bool(void)
+{
+    QemuOptsList *list;
+    QemuOpts *opts;
+    bool opt;
+    int ret;
+
+    list = qemu_find_opts("opts_list_02");
+    g_assert(list != NULL);
+    g_assert(QTAILQ_EMPTY(&list->head));
+    g_assert_cmpstr(list->name, ==, "opts_list_02");
+
+    /* should not find anything at this point */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts == NULL);
+
+    /* create the opts */
+    opts = qemu_opts_create(list, NULL, 0, &error_abort);
+    g_assert(opts != NULL);
+    g_assert(!QTAILQ_EMPTY(&list->head));
+
+    /* haven't set anything to bool1 yet, so defval should be returned */
+    opt = qemu_opt_get_bool(opts, "bool1", false);
+    g_assert(opt == false);
+
+    ret = qemu_opt_set_bool(opts, "bool1", true);
+    g_assert(ret == 0);
+
+    /* now we have set bool1, should know about it */
+    opt = qemu_opt_get_bool(opts, "bool1", false);
+    g_assert(opt == true);
+
+    /* having reset the value, opt should be the reset one not defval */
+    ret = qemu_opt_set_bool(opts, "bool1", false);
+    g_assert(ret == 0);
+
+    opt = qemu_opt_get_bool(opts, "bool1", true);
+    g_assert(opt == false);
+
+    qemu_opts_del(opts);
+
+    /* should not find anything at this point */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts == NULL);
+}
+
+static void test_qemu_opt_get_number(void)
+{
+    QemuOptsList *list;
+    QemuOpts *opts;
+    uint64_t opt;
+    int ret;
+
+    list = qemu_find_opts("opts_list_01");
+    g_assert(list != NULL);
+    g_assert(QTAILQ_EMPTY(&list->head));
+    g_assert_cmpstr(list->name, ==, "opts_list_01");
+
+    /* should not find anything at this point */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts == NULL);
+
+    /* create the opts */
+    opts = qemu_opts_create(list, NULL, 0, &error_abort);
+    g_assert(opts != NULL);
+    g_assert(!QTAILQ_EMPTY(&list->head));
+
+    /* haven't set anything to number1 yet, so defval should be returned */
+    opt = qemu_opt_get_number(opts, "number1", 5);
+    g_assert(opt == 5);
+
+    ret = qemu_opt_set_number(opts, "number1", 10);
+    g_assert(ret == 0);
+
+    /* now we have set number1, should know about it */
+    opt = qemu_opt_get_number(opts, "number1", 5);
+    g_assert(opt == 10);
+
+    /* having reset it, the returned should be the reset one not defval */
+    ret = qemu_opt_set_number(opts, "number1", 15);
+    g_assert(ret == 0);
+
+    opt = qemu_opt_get_number(opts, "number1", 5);
+    g_assert(opt == 15);
+
+    qemu_opts_del(opts);
+
+    /* should not find anything at this point */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts == NULL);
+}
+
+static void test_qemu_opt_get_size(void)
+{
+    QemuOptsList *list;
+    QemuOpts *opts;
+    uint64_t opt;
+    QDict *dict;
+
+    list = qemu_find_opts("opts_list_02");
+    g_assert(list != NULL);
+    g_assert(QTAILQ_EMPTY(&list->head));
+    g_assert_cmpstr(list->name, ==, "opts_list_02");
+
+    /* should not find anything at this point */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts == NULL);
+
+    /* create the opts */
+    opts = qemu_opts_create(list, NULL, 0, &error_abort);
+    g_assert(opts != NULL);
+    g_assert(!QTAILQ_EMPTY(&list->head));
+
+    /* haven't set anything to size1 yet, so defval should be returned */
+    opt = qemu_opt_get_size(opts, "size1", 5);
+    g_assert(opt == 5);
+
+    dict = qdict_new();
+    g_assert(dict != NULL);
+
+    qdict_put(dict, "size1", qstring_from_str("10"));
+
+    qemu_opts_absorb_qdict(opts, dict, &error_abort);
+    g_assert(error_abort == NULL);
+
+    /* now we have set size1, should know about it */
+    opt = qemu_opt_get_size(opts, "size1", 5);
+    g_assert(opt == 10);
+
+    /* reset value */
+    qdict_put(dict, "size1", qstring_from_str("15"));
+
+    qemu_opts_absorb_qdict(opts, dict, &error_abort);
+    g_assert(error_abort == NULL);
+
+    /* test the reset value */
+    opt = qemu_opt_get_size(opts, "size1", 5);
+    g_assert(opt == 15);
+
+    qdict_del(dict, "size1");
+    g_free(dict);
+
+    qemu_opts_del(opts);
+
+    /* should not find anything at this point */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts == NULL);
+}
+
+static void test_qemu_opt_unset(void)
+{
+    QemuOpts *opts;
+    const char *value;
+    int ret;
+
+    /* dynamically initialized (parsed) opts */
+    opts = qemu_opts_parse(&opts_list_03, "key=value", 0);
+    g_assert(opts != NULL);
+
+    /* check default/parsed value */
+    value = qemu_opt_get(opts, "key");
+    g_assert_cmpstr(value, ==, "value");
+
+    /* reset it to value2 */
+    qemu_opt_set(opts, "key", "value2");
+
+    value = qemu_opt_get(opts, "key");
+    g_assert_cmpstr(value, ==, "value2");
+
+    /* unset, valid only for "accept any" */
+    ret = qemu_opt_unset(opts, "key");
+    g_assert(ret == 0);
+
+    /* after reset the value should be the parsed/default one */
+    value = qemu_opt_get(opts, "key");
+    g_assert_cmpstr(value, ==, "value");
+
+    qemu_opts_del(opts);
+}
+
+static void test_qemu_opts_reset(void)
+{
+    QemuOptsList *list;
+    QemuOpts *opts;
+    uint64_t opt;
+    int ret;
+
+    list = qemu_find_opts("opts_list_01");
+    g_assert(list != NULL);
+    g_assert(QTAILQ_EMPTY(&list->head));
+    g_assert_cmpstr(list->name, ==, "opts_list_01");
+
+    /* should not find anything at this point */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts == NULL);
+
+    /* create the opts */
+    opts = qemu_opts_create(list, NULL, 0, &error_abort);
+    g_assert(opts != NULL);
+    g_assert(!QTAILQ_EMPTY(&list->head));
+
+    /* haven't set anything to number1 yet, so defval should be returned */
+    opt = qemu_opt_get_number(opts, "number1", 5);
+    g_assert(opt == 5);
+
+    ret = qemu_opt_set_number(opts, "number1", 10);
+    g_assert(ret == 0);
+
+    /* now we have set number1, should know about it */
+    opt = qemu_opt_get_number(opts, "number1", 5);
+    g_assert(opt == 10);
+
+    qemu_opts_reset(list);
+
+    /* should not find anything at this point */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts == NULL);
+}
+
+static void test_qemu_opts_set(void)
+{
+    QemuOptsList *list;
+    QemuOpts *opts;
+    int ret;
+    const char *opt;
+
+    list = qemu_find_opts("opts_list_01");
+    g_assert(list != NULL);
+    g_assert(QTAILQ_EMPTY(&list->head));
+    g_assert_cmpstr(list->name, ==, "opts_list_01");
+
+    /* should not find anything at this point */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts == NULL);
+
+    /* implicitly create opts and set str3 value */
+    ret = qemu_opts_set(list, NULL, "str3", "value");
+    g_assert(ret == 0);
+    g_assert(!QTAILQ_EMPTY(&list->head));
+
+    /* get the just created opts */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts != NULL);
+
+    /* check the str3 value */
+    opt = qemu_opt_get(opts, "str3");
+    g_assert_cmpstr(opt, ==, "value");
+
+    qemu_opts_del(opts);
+
+    /* should not find anything at this point */
+    opts = qemu_opts_find(list, NULL);
+    g_assert(opts == NULL);
+}
+
+int main(int argc, char *argv[])
+{
+    register_opts();
+    g_test_init(&argc, &argv, NULL);
+    g_test_add_func("/qemu-opts/find_unknown_opts", test_find_unknown_opts);
+    g_test_add_func("/qemu-opts/find_opts", test_qemu_find_opts);
+    g_test_add_func("/qemu-opts/opts_create", test_qemu_opts_create);
+    g_test_add_func("/qemu-opts/opt_get", test_qemu_opt_get);
+    g_test_add_func("/qemu-opts/opt_get_bool", test_qemu_opt_get_bool);
+    g_test_add_func("/qemu-opts/opt_get_number", test_qemu_opt_get_number);
+    g_test_add_func("/qemu-opts/opt_get_size", test_qemu_opt_get_size);
+    g_test_add_func("/qemu-opts/opt_unset", test_qemu_opt_unset);
+    g_test_add_func("/qemu-opts/opts_reset", test_qemu_opts_reset);
+    g_test_add_func("/qemu-opts/opts_set", test_qemu_opts_set);
+    g_test_run();
+    return 0;
+}
diff --git a/tests/test-thread-pool.c b/tests/test-thread-pool.c
index c1f8e13a9f..aa156bcd32 100644
--- a/tests/test-thread-pool.c
+++ b/tests/test-thread-pool.c
@@ -180,7 +180,7 @@ static void test_cancel(void)
 
     /* Canceling the others will be a blocking operation.  */
     for (i = 0; i < 100; i++) {
-        if (data[i].n != 3) {
+        if (data[i].aiocb && data[i].n != 3) {
             bdrv_aio_cancel(data[i].aiocb);
         }
     }
diff --git a/thread-pool.c b/thread-pool.c
index fbdd3ffa3a..dfb699dd94 100644
--- a/thread-pool.c
+++ b/thread-pool.c
@@ -224,6 +224,7 @@ static void thread_pool_cancel(BlockDriverAIOCB *acb)
         pool->pending_cancellations--;
     }
     qemu_mutex_unlock(&pool->lock);
+    event_notifier_ready(&pool->notifier);
 }
 
 static const AIOCBInfo thread_pool_aiocb_info = {