Merge remote-tracking branch 'stefanha/block' into staging

# By Wenchao Xia (5) and others
# Via Stefan Hajnoczi
* stefanha/block:
  coroutine: stop using AioContext in CoQueue
  coroutine: protect global pool with a mutex
  qemu-iotests: Try creating huge qcow2 image
  qcow2.py: Subcommand for changing header fields
  qemu-io: Fix 'map' output
  blockdev: Rename BlockdevAction -> TransactionAction
  block: make all steps in qmp_transaction() as callback
  block: package rollback code in qmp_transaction()
  block: package committing code in qmp_transaction()
  block: move input parsing code in qmp_transaction()
  block: package preparation code in qmp_transaction()

Message-id: 1369405947-14818-1-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

12 files changed, 361 insertions, 159 deletions

diff --git a/blockdev.c b/blockdev.c
index 7c9d8dd0ac..d1ec99af73 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -750,8 +750,8 @@ void do_commit(Monitor *mon, const QDict *qdict)
 
 static void blockdev_do_action(int kind, void *data, Error **errp)
 {
-    BlockdevAction action;
-    BlockdevActionList list;
+    TransactionAction action;
+    TransactionActionList list;
 
     action.kind = kind;
     action.data = data;
@@ -773,27 +773,176 @@ void qmp_blockdev_snapshot_sync(const char *device, const char *snapshot_file,
         .has_mode = has_mode,
         .mode = mode,
     };
-    blockdev_do_action(BLOCKDEV_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC, &snapshot,
-                       errp);
+    blockdev_do_action(TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC,
+                       &snapshot, errp);
 }
 
 
 /* New and old BlockDriverState structs for group snapshots */
-typedef struct BlkTransactionStates {
+
+typedef struct BlkTransactionStates BlkTransactionStates;
+
+/* Only prepare() may fail. In a single transaction, only one of commit() or
+   abort() will be called, clean() will always be called if it present. */
+typedef struct BdrvActionOps {
+    /* Size of state struct, in bytes. */
+    size_t instance_size;
+    /* Prepare the work, must NOT be NULL. */
+    void (*prepare)(BlkTransactionStates *common, Error **errp);
+    /* Commit the changes, must NOT be NULL. */
+    void (*commit)(BlkTransactionStates *common);
+    /* Abort the changes on fail, can be NULL. */
+    void (*abort)(BlkTransactionStates *common);
+    /* Clean up resource in the end, can be NULL. */
+    void (*clean)(BlkTransactionStates *common);
+} BdrvActionOps;
+
+/*
+ * This structure must be arranged as first member in child type, assuming
+ * that compiler will also arrange it to the same address with parent instance.
+ * Later it will be used in free().
+ */
+struct BlkTransactionStates {
+    TransactionAction *action;
+    const BdrvActionOps *ops;
+    QSIMPLEQ_ENTRY(BlkTransactionStates) entry;
+};
+
+/* external snapshot private data */
+typedef struct ExternalSnapshotStates {
+    BlkTransactionStates common;
     BlockDriverState *old_bs;
     BlockDriverState *new_bs;
-    QSIMPLEQ_ENTRY(BlkTransactionStates) entry;
-} BlkTransactionStates;
+} ExternalSnapshotStates;
+
+static void external_snapshot_prepare(BlkTransactionStates *common,
+                                      Error **errp)
+{
+    BlockDriver *proto_drv;
+    BlockDriver *drv;
+    int flags, ret;
+    Error *local_err = NULL;
+    const char *device;
+    const char *new_image_file;
+    const char *format = "qcow2";
+    enum NewImageMode mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
+    ExternalSnapshotStates *states =
+                             DO_UPCAST(ExternalSnapshotStates, common, common);
+    TransactionAction *action = common->action;
+
+    /* get parameters */
+    g_assert(action->kind == TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC);
+
+    device = action->blockdev_snapshot_sync->device;
+    new_image_file = action->blockdev_snapshot_sync->snapshot_file;
+    if (action->blockdev_snapshot_sync->has_format) {
+        format = action->blockdev_snapshot_sync->format;
+    }
+    if (action->blockdev_snapshot_sync->has_mode) {
+        mode = action->blockdev_snapshot_sync->mode;
+    }
+
+    /* start processing */
+    drv = bdrv_find_format(format);
+    if (!drv) {
+        error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
+        return;
+    }
+
+    states->old_bs = bdrv_find(device);
+    if (!states->old_bs) {
+        error_set(errp, QERR_DEVICE_NOT_FOUND, device);
+        return;
+    }
+
+    if (!bdrv_is_inserted(states->old_bs)) {
+        error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
+        return;
+    }
+
+    if (bdrv_in_use(states->old_bs)) {
+        error_set(errp, QERR_DEVICE_IN_USE, device);
+        return;
+    }
+
+    if (!bdrv_is_read_only(states->old_bs)) {
+        if (bdrv_flush(states->old_bs)) {
+            error_set(errp, QERR_IO_ERROR);
+            return;
+        }
+    }
+
+    flags = states->old_bs->open_flags;
+
+    proto_drv = bdrv_find_protocol(new_image_file);
+    if (!proto_drv) {
+        error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
+        return;
+    }
+
+    /* create new image w/backing file */
+    if (mode != NEW_IMAGE_MODE_EXISTING) {
+        bdrv_img_create(new_image_file, format,
+                        states->old_bs->filename,
+                        states->old_bs->drv->format_name,
+                        NULL, -1, flags, &local_err, false);
+        if (error_is_set(&local_err)) {
+            error_propagate(errp, local_err);
+            return;
+        }
+    }
+
+    /* We will manually add the backing_hd field to the bs later */
+    states->new_bs = bdrv_new("");
+    /* TODO Inherit bs->options or only take explicit options with an
+     * extended QMP command? */
+    ret = bdrv_open(states->new_bs, new_image_file, NULL,
+                    flags | BDRV_O_NO_BACKING, drv);
+    if (ret != 0) {
+        error_set(errp, QERR_OPEN_FILE_FAILED, new_image_file);
+    }
+}
+
+static void external_snapshot_commit(BlkTransactionStates *common)
+{
+    ExternalSnapshotStates *states =
+                             DO_UPCAST(ExternalSnapshotStates, common, common);
+
+    /* This removes our old bs from the bdrv_states, and adds the new bs */
+    bdrv_append(states->new_bs, states->old_bs);
+    /* We don't need (or want) to use the transactional
+     * bdrv_reopen_multiple() across all the entries at once, because we
+     * don't want to abort all of them if one of them fails the reopen */
+    bdrv_reopen(states->new_bs, states->new_bs->open_flags & ~BDRV_O_RDWR,
+                NULL);
+}
+
+static void external_snapshot_abort(BlkTransactionStates *common)
+{
+    ExternalSnapshotStates *states =
+                             DO_UPCAST(ExternalSnapshotStates, common, common);
+    if (states->new_bs) {
+        bdrv_delete(states->new_bs);
+    }
+}
+
+static const BdrvActionOps actions[] = {
+    [TRANSACTION_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC] = {
+        .instance_size = sizeof(ExternalSnapshotStates),
+        .prepare  = external_snapshot_prepare,
+        .commit   = external_snapshot_commit,
+        .abort = external_snapshot_abort,
+    },
+};
 
 /*
  * 'Atomic' group snapshots.  The snapshots are taken as a set, and if any fail
  *  then we do not pivot any of the devices in the group, and abandon the
  *  snapshots
  */
-void qmp_transaction(BlockdevActionList *dev_list, Error **errp)
+void qmp_transaction(TransactionActionList *dev_list, Error **errp)
 {
-    int ret = 0;
-    BlockdevActionList *dev_entry = dev_list;
+    TransactionActionList *dev_entry = dev_list;
     BlkTransactionStates *states, *next;
     Error *local_err = NULL;
 
@@ -805,109 +954,29 @@ void qmp_transaction(BlockdevActionList *dev_list, Error **errp)
 
     /* We don't do anything in this loop that commits us to the snapshot */
     while (NULL != dev_entry) {
-        BlockdevAction *dev_info = NULL;
-        BlockDriver *proto_drv;
-        BlockDriver *drv;
-        int flags;
-        enum NewImageMode mode;
-        const char *new_image_file;
-        const char *device;
-        const char *format = "qcow2";
+        TransactionAction *dev_info = NULL;
+        const BdrvActionOps *ops;
 
         dev_info = dev_entry->value;
         dev_entry = dev_entry->next;
 
-        states = g_malloc0(sizeof(BlkTransactionStates));
-        QSIMPLEQ_INSERT_TAIL(&snap_bdrv_states, states, entry);
-
-        switch (dev_info->kind) {
-        case BLOCKDEV_ACTION_KIND_BLOCKDEV_SNAPSHOT_SYNC:
-            device = dev_info->blockdev_snapshot_sync->device;
-            if (!dev_info->blockdev_snapshot_sync->has_mode) {
-                dev_info->blockdev_snapshot_sync->mode = NEW_IMAGE_MODE_ABSOLUTE_PATHS;
-            }
-            new_image_file = dev_info->blockdev_snapshot_sync->snapshot_file;
-            if (dev_info->blockdev_snapshot_sync->has_format) {
-                format = dev_info->blockdev_snapshot_sync->format;
-            }
-            mode = dev_info->blockdev_snapshot_sync->mode;
-            break;
-        default:
-            abort();
-        }
+        assert(dev_info->kind < ARRAY_SIZE(actions));
 
-        drv = bdrv_find_format(format);
-        if (!drv) {
-            error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
-            goto delete_and_fail;
-        }
-
-        states->old_bs = bdrv_find(device);
-        if (!states->old_bs) {
-            error_set(errp, QERR_DEVICE_NOT_FOUND, device);
-            goto delete_and_fail;
-        }
-
-        if (!bdrv_is_inserted(states->old_bs)) {
-            error_set(errp, QERR_DEVICE_HAS_NO_MEDIUM, device);
-            goto delete_and_fail;
-        }
-
-        if (bdrv_in_use(states->old_bs)) {
-            error_set(errp, QERR_DEVICE_IN_USE, device);
-            goto delete_and_fail;
-        }
-
-        if (!bdrv_is_read_only(states->old_bs)) {
-            if (bdrv_flush(states->old_bs)) {
-                error_set(errp, QERR_IO_ERROR);
-                goto delete_and_fail;
-            }
-        }
-
-        flags = states->old_bs->open_flags;
-
-        proto_drv = bdrv_find_protocol(new_image_file);
-        if (!proto_drv) {
-            error_set(errp, QERR_INVALID_BLOCK_FORMAT, format);
-            goto delete_and_fail;
-        }
-
-        /* create new image w/backing file */
-        if (mode != NEW_IMAGE_MODE_EXISTING) {
-            bdrv_img_create(new_image_file, format,
-                            states->old_bs->filename,
-                            states->old_bs->drv->format_name,
-                            NULL, -1, flags, &local_err, false);
-            if (error_is_set(&local_err)) {
-                error_propagate(errp, local_err);
-                goto delete_and_fail;
-            }
-        }
+        ops = &actions[dev_info->kind];
+        states = g_malloc0(ops->instance_size);
+        states->ops = ops;
+        states->action = dev_info;
+        QSIMPLEQ_INSERT_TAIL(&snap_bdrv_states, states, entry);
 
-        /* We will manually add the backing_hd field to the bs later */
-        states->new_bs = bdrv_new("");
-        /* TODO Inherit bs->options or only take explicit options with an
-         * extended QMP command? */
-        ret = bdrv_open(states->new_bs, new_image_file, NULL,
-                        flags | BDRV_O_NO_BACKING, drv);
-        if (ret != 0) {
-            error_set(errp, QERR_OPEN_FILE_FAILED, new_image_file);
+        states->ops->prepare(states, &local_err);
+        if (error_is_set(&local_err)) {
+            error_propagate(errp, local_err);
             goto delete_and_fail;
         }
     }
 
-
-    /* Now we are going to do the actual pivot.  Everything up to this point
-     * is reversible, but we are committed at this point */
     QSIMPLEQ_FOREACH(states, &snap_bdrv_states, entry) {
-        /* This removes our old bs from the bdrv_states, and adds the new bs */
-        bdrv_append(states->new_bs, states->old_bs);
-        /* We don't need (or want) to use the transactional
-         * bdrv_reopen_multiple() across all the entries at once, because we
-         * don't want to abort all of them if one of them fails the reopen */
-        bdrv_reopen(states->new_bs, states->new_bs->open_flags & ~BDRV_O_RDWR,
-                    NULL);
+        states->ops->commit(states);
     }
 
     /* success */
@@ -919,12 +988,15 @@ delete_and_fail:
     * the original bs for all images
     */
     QSIMPLEQ_FOREACH(states, &snap_bdrv_states, entry) {
-        if (states->new_bs) {
-             bdrv_delete(states->new_bs);
+        if (states->ops->abort) {
+            states->ops->abort(states);
         }
     }
 exit:
     QSIMPLEQ_FOREACH_SAFE(states, &snap_bdrv_states, entry, next) {
+        if (states->ops->clean) {
+            states->ops->clean(states);
+        }
         g_free(states);
     }
 }
diff --git a/include/block/coroutine_int.h b/include/block/coroutine_int.h
index 17eb71e723..f133d65af8 100644
--- a/include/block/coroutine_int.h
+++ b/include/block/coroutine_int.h
@@ -38,6 +38,9 @@ struct Coroutine {
     void *entry_arg;
     Coroutine *caller;
     QSLIST_ENTRY(Coroutine) pool_next;
+
+    /* Coroutines that should be woken up when we yield or terminate */
+    QTAILQ_HEAD(, Coroutine) co_queue_wakeup;
     QTAILQ_ENTRY(Coroutine) co_queue_next;
 };
 
@@ -45,5 +48,6 @@ Coroutine *qemu_coroutine_new(void);
 void qemu_coroutine_delete(Coroutine *co);
 CoroutineAction qemu_coroutine_switch(Coroutine *from, Coroutine *to,
                                       CoroutineAction action);
+void coroutine_fn qemu_co_queue_run_restart(Coroutine *co);
 
 #endif
diff --git a/qapi-schema.json b/qapi-schema.json
index 664b31f035..ef1f657efb 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -1609,12 +1609,12 @@
             '*mode': 'NewImageMode' } }
 
 ##
-# @BlockdevAction
+# @TransactionAction
 #
 # A discriminated record of operations that can be performed with
 # @transaction.
 ##
-{ 'union': 'BlockdevAction',
+{ 'union': 'TransactionAction',
   'data': {
        'blockdev-snapshot-sync': 'BlockdevSnapshot'
    } }
@@ -1622,25 +1622,24 @@
 ##
 # @transaction
 #
-# Atomically operate on a group of one or more block devices.  If
-# any operation fails, then the entire set of actions will be
-# abandoned and the appropriate error returned.  The only operation
-# supported is currently blockdev-snapshot-sync.
+# Executes a number of transactionable QMP commands atomically. If any
+# operation fails, then the entire set of actions will be abandoned and the
+# appropriate error returned.
 #
 #  List of:
-#  @BlockdevAction: information needed for the device snapshot
+#  @TransactionAction: information needed for the respective operation
 #
 # Returns: nothing on success
-#          If @device is not a valid block device, DeviceNotFound
+#          Errors depend on the operations of the transaction
 #
-# Note: The transaction aborts on the first failure.  Therefore, there will
-# be only one device or snapshot file returned in an error condition, and
+# Note: The transaction aborts on the first failure.  Therefore, there will be
+# information on only one failed operation returned in an error condition, and
 # subsequent actions will not have been attempted.
 #
 # Since 1.1
 ##
 { 'command': 'transaction',
-  'data': { 'actions': [ 'BlockdevAction' ] } }
+  'data': { 'actions': [ 'TransactionAction' ] } }
 
 ##
 # @blockdev-snapshot-sync
diff --git a/qemu-coroutine-lock.c b/qemu-coroutine-lock.c
index 86efe1f86a..d9fea4989d 100644
--- a/qemu-coroutine-lock.c
+++ b/qemu-coroutine-lock.c
@@ -26,39 +26,11 @@
 #include "block/coroutine.h"
 #include "block/coroutine_int.h"
 #include "qemu/queue.h"
-#include "block/aio.h"
 #include "trace.h"
 
-/* Coroutines are awoken from a BH to allow the current coroutine to complete
- * its flow of execution.  The BH may run after the CoQueue has been destroyed,
- * so keep BH data in a separate heap-allocated struct.
- */
-typedef struct {
-    QEMUBH *bh;
-    QTAILQ_HEAD(, Coroutine) entries;
-} CoQueueNextData;
-
-static void qemu_co_queue_next_bh(void *opaque)
-{
-    CoQueueNextData *data = opaque;
-    Coroutine *next;
-
-    trace_qemu_co_queue_next_bh();
-    while ((next = QTAILQ_FIRST(&data->entries))) {
-        QTAILQ_REMOVE(&data->entries, next, co_queue_next);
-        qemu_coroutine_enter(next, NULL);
-    }
-
-    qemu_bh_delete(data->bh);
-    g_slice_free(CoQueueNextData, data);
-}
-
 void qemu_co_queue_init(CoQueue *queue)
 {
     QTAILQ_INIT(&queue->entries);
-
-    /* This will be exposed to callers once there are multiple AioContexts */
-    queue->ctx = qemu_get_aio_context();
 }
 
 void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
@@ -77,23 +49,37 @@ void coroutine_fn qemu_co_queue_wait_insert_head(CoQueue *queue)
     assert(qemu_in_coroutine());
 }
 
+/**
+ * qemu_co_queue_run_restart:
+ *
+ * Enter each coroutine that was previously marked for restart by
+ * qemu_co_queue_next() or qemu_co_queue_restart_all().  This function is
+ * invoked by the core coroutine code when the current coroutine yields or
+ * terminates.
+ */
+void qemu_co_queue_run_restart(Coroutine *co)
+{
+    Coroutine *next;
+
+    trace_qemu_co_queue_run_restart(co);
+    while ((next = QTAILQ_FIRST(&co->co_queue_wakeup))) {
+        QTAILQ_REMOVE(&co->co_queue_wakeup, next, co_queue_next);
+        qemu_coroutine_enter(next, NULL);
+    }
+}
+
 static bool qemu_co_queue_do_restart(CoQueue *queue, bool single)
 {
+    Coroutine *self = qemu_coroutine_self();
     Coroutine *next;
-    CoQueueNextData *data;
 
     if (QTAILQ_EMPTY(&queue->entries)) {
         return false;
     }
 
-    data = g_slice_new(CoQueueNextData);
-    data->bh = aio_bh_new(queue->ctx, qemu_co_queue_next_bh, data);
-    QTAILQ_INIT(&data->entries);
-    qemu_bh_schedule(data->bh);
-
     while ((next = QTAILQ_FIRST(&queue->entries)) != NULL) {
         QTAILQ_REMOVE(&queue->entries, next, co_queue_next);
-        QTAILQ_INSERT_TAIL(&data->entries, next, co_queue_next);
+        QTAILQ_INSERT_TAIL(&self->co_queue_wakeup, next, co_queue_next);
         trace_qemu_co_queue_next(next);
         if (single) {
             break;
diff --git a/qemu-coroutine.c b/qemu-coroutine.c
index 25a14c605d..423430d3a0 100644
--- a/qemu-coroutine.c
+++ b/qemu-coroutine.c
@@ -14,6 +14,7 @@
 
 #include "trace.h"
 #include "qemu-common.h"
+#include "qemu/thread.h"
 #include "block/coroutine.h"
 #include "block/coroutine_int.h"
 
@@ -23,6 +24,7 @@ enum {
 };
 
 /** Free list to speed up creation */
+static QemuMutex pool_lock;
 static QSLIST_HEAD(, Coroutine) pool = QSLIST_HEAD_INITIALIZER(pool);
 static unsigned int pool_size;
 
@@ -30,31 +32,44 @@ Coroutine *qemu_coroutine_create(CoroutineEntry *entry)
 {
     Coroutine *co;
 
+    qemu_mutex_lock(&pool_lock);
     co = QSLIST_FIRST(&pool);
     if (co) {
         QSLIST_REMOVE_HEAD(&pool, pool_next);
         pool_size--;
-    } else {
+    }
+    qemu_mutex_unlock(&pool_lock);
+
+    if (!co) {
         co = qemu_coroutine_new();
     }
 
     co->entry = entry;
+    QTAILQ_INIT(&co->co_queue_wakeup);
     return co;
 }
 
 static void coroutine_delete(Coroutine *co)
 {
+    qemu_mutex_lock(&pool_lock);
     if (pool_size < POOL_MAX_SIZE) {
         QSLIST_INSERT_HEAD(&pool, co, pool_next);
         co->caller = NULL;
         pool_size++;
+        qemu_mutex_unlock(&pool_lock);
         return;
     }
+    qemu_mutex_unlock(&pool_lock);
 
     qemu_coroutine_delete(co);
 }
 
-static void __attribute__((destructor)) coroutine_cleanup(void)
+static void __attribute__((constructor)) coroutine_pool_init(void)
+{
+    qemu_mutex_init(&pool_lock);
+}
+
+static void __attribute__((destructor)) coroutine_pool_cleanup(void)
 {
     Coroutine *co;
     Coroutine *tmp;
@@ -63,6 +78,8 @@ static void __attribute__((destructor)) coroutine_cleanup(void)
         QSLIST_REMOVE_HEAD(&pool, pool_next);
         qemu_coroutine_delete(co);
     }
+
+    qemu_mutex_destroy(&pool_lock);
 }
 
 static void coroutine_swap(Coroutine *from, Coroutine *to)
@@ -71,6 +88,8 @@ static void coroutine_swap(Coroutine *from, Coroutine *to)
 
     ret = qemu_coroutine_switch(from, to, COROUTINE_YIELD);
 
+    qemu_co_queue_run_restart(to);
+
     switch (ret) {
     case COROUTINE_YIELD:
         return;
diff --git a/qemu-io.c b/qemu-io.c
index 475a8bd034..5e6680b247 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -1635,12 +1635,43 @@ static const cmdinfo_t alloc_cmd = {
     .oneline    = "checks if a sector is present in the file",
 };
 
+
+static int map_is_allocated(int64_t sector_num, int64_t nb_sectors, int64_t *pnum)
+{
+    int num, num_checked;
+    int ret, firstret;
+
+    num_checked = MIN(nb_sectors, INT_MAX);
+    ret = bdrv_is_allocated(bs, sector_num, num_checked, &num);
+    if (ret < 0) {
+        return ret;
+    }
+
+    firstret = ret;
+    *pnum = num;
+
+    while (nb_sectors > 0 && ret == firstret) {
+        sector_num += num;
+        nb_sectors -= num;
+
+        num_checked = MIN(nb_sectors, INT_MAX);
+        ret = bdrv_is_allocated(bs, sector_num, num_checked, &num);
+        if (ret == firstret) {
+            *pnum += num;
+        } else {
+            break;
+        }
+    }
+
+    return firstret;
+}
+
 static int map_f(int argc, char **argv)
 {
     int64_t offset;
     int64_t nb_sectors;
     char s1[64];
-    int num, num_checked;
+    int64_t num;
     int ret;
     const char *retstr;
 
@@ -1648,12 +1679,17 @@ static int map_f(int argc, char **argv)
     nb_sectors = bs->total_sectors;
 
     do {
-        num_checked = MIN(nb_sectors, INT_MAX);
-        ret = bdrv_is_allocated(bs, offset, num_checked, &num);
+        ret = map_is_allocated(offset, nb_sectors, &num);
+        if (ret < 0) {
+            error_report("Failed to get allocation status: %s", strerror(-ret));
+            return 0;
+        }
+
         retstr = ret ? "    allocated" : "not allocated";
         cvtstr(offset << 9ULL, s1, sizeof(s1));
-        printf("[% 24" PRId64 "] % 8d/% 8d sectors %s at offset %s (%d)\n",
-               offset << 9ULL, num, num_checked, retstr, s1, ret);
+        printf("[% 24" PRId64 "] % 8" PRId64 "/% 8" PRId64 " sectors %s "
+               "at offset %s (%d)\n",
+               offset << 9ULL, num, nb_sectors, retstr, s1, ret);
 
         offset += num;
         nb_sectors -= num;
diff --git a/tests/qemu-iotests/054 b/tests/qemu-iotests/054
new file mode 100755
index 0000000000..b36042958c
--- /dev/null
+++ b/tests/qemu-iotests/054
@@ -0,0 +1,58 @@
+#!/bin/bash
+#
+# Test huge qcow2 images
+#
+# Copyright (C) 2013 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
+
+echo
+echo "creating too large image (1 EB)"
+_make_test_img $((1024*1024))T
+
+echo
+echo "creating too large image (1 EB) using qcow2.py"
+_make_test_img 4G
+./qcow2.py $TEST_IMG set-header size $((1024 ** 6))
+_check_test_img
+
+# success, all done
+echo "*** done"
+rm -f $seq.full
+status=0
diff --git a/tests/qemu-iotests/054.out b/tests/qemu-iotests/054.out
new file mode 100644
index 0000000000..0b2fe301ea
--- /dev/null
+++ b/tests/qemu-iotests/054.out
@@ -0,0 +1,10 @@
+QA output created by 054
+
+creating too large image (1 EB)
+qemu-img: The image size is too large for file format 'qcow2'
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1152921504606846976 
+
+creating too large image (1 EB) using qcow2.py
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4294967296 
+qemu-img: Could not open 'TEST_DIR/t.qcow2': File too large
+*** done
diff --git a/tests/qemu-iotests/common.rc b/tests/qemu-iotests/common.rc
index 31eb62b604..e9ba3586b5 100644
--- a/tests/qemu-iotests/common.rc
+++ b/tests/qemu-iotests/common.rc
@@ -167,7 +167,7 @@ _cleanup_test_img()
 
 _check_test_img()
 {
-    $QEMU_IMG check "$@" -f $IMGFMT $TEST_IMG 2>&1 | \
+    $QEMU_IMG check "$@" -f $IMGFMT $TEST_IMG 2>&1 | _filter_testdir | \
         sed -e '/allocated.*fragmented.*compressed clusters/d' \
             -e 's/qemu-img: This image format does not support checks/No errors were found on the image./' \
             -e '/Image end offset: [0-9]\+/d'
diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
index bf944d9123..387b050987 100644
--- a/tests/qemu-iotests/group
+++ b/tests/qemu-iotests/group
@@ -60,3 +60,4 @@
 #051 rw auto
 052 rw auto backing
 053 rw auto
+054 rw auto
diff --git a/tests/qemu-iotests/qcow2.py b/tests/qemu-iotests/qcow2.py
index fecf5b9a59..44a2b45641 100755
--- a/tests/qemu-iotests/qcow2.py
+++ b/tests/qemu-iotests/qcow2.py
@@ -149,6 +149,22 @@ def cmd_dump_header(fd):
     h.dump()
     h.dump_extensions()
 
+def cmd_set_header(fd, name, value):
+    try:
+        value = int(value, 0)
+    except:
+        print "'%s' is not a valid number" % value
+        sys.exit(1)
+
+    fields = (field[2] for field in QcowHeader.fields)
+    if not name in fields:
+        print "'%s' is not a known header field" % name
+        sys.exit(1)
+
+    h = QcowHeader(fd)
+    h.__dict__[name] = value
+    h.update(fd)
+
 def cmd_add_header_ext(fd, magic, data):
     try:
         magic = int(magic, 0)
@@ -205,6 +221,7 @@ def cmd_set_feature_bit(fd, group, bit):
 
 cmds = [
     [ 'dump-header',    cmd_dump_header,    0, 'Dump image header and header extensions' ],
+    [ 'set-header',     cmd_set_header,     2, 'Set a field in the header'],
     [ 'add-header-ext', cmd_add_header_ext, 2, 'Add a header extension' ],
     [ 'del-header-ext', cmd_del_header_ext, 1, 'Delete a header extension' ],
     [ 'set-feature-bit', cmd_set_feature_bit, 2, 'Set a feature bit'],
diff --git a/trace-events b/trace-events
index 9c73931f37..f51408aeb2 100644
--- a/trace-events
+++ b/trace-events
@@ -825,7 +825,7 @@ qemu_coroutine_yield(void *from, void *to) "from %p to %p"
 qemu_coroutine_terminate(void *co) "self %p"
 
 # qemu-coroutine-lock.c
-qemu_co_queue_next_bh(void) ""
+qemu_co_queue_run_restart(void *co) "co %p"
 qemu_co_queue_next(void *nxt) "next %p"
 qemu_co_mutex_lock_entry(void *mutex, void *self) "mutex %p self %p"
 qemu_co_mutex_lock_return(void *mutex, void *self) "mutex %p self %p"