Management software, such as OpenStack and RHEV's vdsm, want to be able
to allocate disk space on demand. The basic use case is to start a VM
with a small disk and then the disk is enlarged when QEMU hits a ENOSPC
condition.
To this end, the management software has to be notified when QEMU
encounters ENOSPC. The solution implemented by this commit is simple:
it extends the BLOCK_IO_ERROR with a 'nospace' key, which is true
when QEMU is stopped due to ENOSPC.
Note that support for quering this event is already present in
query-block by means of the 'io-status' key and that the new 'nospace'
BLOCK_IO_ERROR field shares the same semantics with 'io-status',
which basically means that werror= has to be set to either
'stop' or 'enospc'.
Signed-off-by: Luiz Capitulino <lcapitul...@redhat.com>
---
block.c | 22 ++++++++++++++--------
qapi/block-core.json | 7 ++++++-
2 files changed, 20 insertions(+), 9 deletions(-)
diff --git a/block.c b/block.c
index 8cf519b..566ef56 100644
--- a/block.c
+++ b/block.c
@@ -3596,6 +3596,18 @@ BlockErrorAction bdrv_get_error_action(BlockDriverState
*bs, bool is_read, int e
}
}
+static void send_qmp_error_event(BlockDriverState *bs,
+ BlockErrorAction action,
+ bool is_read, int error)
+{
+ BlockErrorAction ac;
+
+ ac = is_read ? IO_OPERATION_TYPE_READ : IO_OPERATION_TYPE_WRITE;
+ qapi_event_send_block_io_error(bdrv_get_device_name(bs), ac, action,
+ bdrv_iostatus_is_enabled(bs),
+ error == ENOSPC, &error_abort);
+}
+
/* This is done by device models because, while the block layer knows
* about the error, it does not know whether an operation comes from
* the device or the block layer (from a job, for example).
@@ -3621,16 +3633,10 @@ void bdrv_error_action(BlockDriverState *bs,
BlockErrorAction action,
* also ensures that the STOP/RESUME pair of events is emitted.
*/
qemu_system_vmstop_request_prepare();
- qapi_event_send_block_io_error(bdrv_get_device_name(bs),
- is_read ? IO_OPERATION_TYPE_READ :
- IO_OPERATION_TYPE_WRITE,
- action, &error_abort);
+ send_qmp_error_event(bs, action, is_read, error);
qemu_system_vmstop_request(RUN_STATE_IO_ERROR);
} else {
- qapi_event_send_block_io_error(bdrv_get_device_name(bs),
- is_read ? IO_OPERATION_TYPE_READ :
- IO_OPERATION_TYPE_WRITE,
- action, &error_abort);
+ send_qmp_error_event(bs, action, is_read, error);
}
}
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 1069679..d659165 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -1534,6 +1534,11 @@
#
# @action: action that has been taken
#
+# @nospace: #optional true if I/O error was caused due to a no-space
+# condition. This key is only present if query-block's
+# io-status is present, please see query-block documentation
+# for more information (since: 2.2)
+#
# Note: If action is "stop", a STOP event will eventually follow the
# BLOCK_IO_ERROR event
#
@@ -1541,7 +1546,7 @@
##
{ 'event': 'BLOCK_IO_ERROR',
'data': { 'device': 'str', 'operation': 'IoOperationType',
- 'action': 'BlockErrorAction' } }
+ 'action': 'BlockErrorAction', '*nospace': 'bool' } }
##
# @BLOCK_JOB_COMPLETED
--
1.9.3
