From d6b3fb3db9409f62de3735f967b46fb23e97fda2 Mon Sep 17 00:00:00 2001

From: Luiz Capitulino <lcapitulino@redhat.com>

Date: Wed, 9 Jul 2014 14:31:52 +0200

Subject: qmp: improve debuggability of BLOCK_IO_ERROR event

Message-id: <1404916312-27953-4-git-send-email-lcapitulino@redhat.com>

Patchwork-id: 59730

O-Subject: [RHEV7.1 qemu-kvm-rhev PATCH 3/3] qmp: improve debuggability of BLOCK_IO_ERROR event

Bugzilla: 1116772

RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>

RH-Acked-by: Eric Blake <eblake@redhat.com>

RH-Acked-by: Laszlo Ersek <lersek@redhat.com>

This commit forward ports the following RHEL-7.0 commit to RHEL-7.1:

  commit bfea65d6f229fd65c78ae4daaddf0d0711d0aedd

  Author: Laszlo Ersek <lersek@redhat.com>

  Date:   Thu Nov 21 16:27:19 2013 +0100

  improve debuggability of BLOCK_IO_ERROR / BLOCK_JOB_ERROR (RHEL 6->7 fwd)

I had to redo the work because now events use the QAPI, but it

was straightforward.

There's one significant difference though: this commit does not

extend the BLOCK_JOB_ERROR event as did the RHEL-7.0 commit. The

reason is that the original requirement was to have this only on

the BLOCK_IO_ERROR event. Let's not spread it unless we're asked to.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

diff --git a/block.c b/block.c

index aab65d9..f1b1cd4 100644

--- a/block.c

+++ b/block.c

@@ -3611,6 +3611,13 @@ static RHEL7BlockErrorReason get_rhel7_error_reason(int error)

     }

 }

+static void get_rhel7_error_debug_info(RHEL7BlockErrorDebugInfo *info,

+                                       int error)

+{

+    info->q_errno = error;

+    info->message = strerror(error);

+}

+

 /* 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).

@@ -3619,9 +3626,14 @@ void bdrv_error_action(BlockDriverState *bs, BlockErrorAction action,

                        bool is_read, int error)

 {

     RHEL7BlockErrorReason res;

+    RHEL7BlockErrorDebugInfo info;

     assert(error >= 0);

     res = get_rhel7_error_reason(error);

+    get_rhel7_error_debug_info(&info, error);

+

+    fprintf(stderr, "block I/O error in device '%s': %s (%d)\n",

+                    bdrv_get_device_name(bs), info.message, (int) info.q_errno);

     if (action == BLOCK_ERROR_ACTION_STOP) {

         /* First set the iostatus, so that "info block" returns an iostatus

@@ -3642,13 +3654,13 @@ void bdrv_error_action(BlockDriverState *bs, BlockErrorAction action,

         qapi_event_send_block_io_error(bdrv_get_device_name(bs),

                                        is_read ? IO_OPERATION_TYPE_READ :

                                        IO_OPERATION_TYPE_WRITE,

-                                       action, res, &error_abort);

+                                       action, res, &info, &error_abort);

         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, res, &error_abort);

+                                       action, res, &info, &error_abort);

     }

 }

diff --git a/docs/qmp/qmp-events.txt b/docs/qmp/qmp-events.txt

index 40c2917..c9dec63 100644

--- a/docs/qmp/qmp-events.txt

+++ b/docs/qmp/qmp-events.txt

@@ -69,6 +69,11 @@ Data:

 	"eperm": errno EPERM

 	"enospc": errno ENOSPC

 	"eother": any other errno (other than EIO, EPERM, ENOSPC)

+- "__com.redhat_debug_info": RHEL7 extension containing debug information for

+                             humans, applications should NOT read any

+                             information from this member (json-object):

+	- "errno": errno value (json-int)

+	- "message": error message returned by strerror() (json-string)

 Example:

@@ -76,7 +81,10 @@ Example:

     "data": { "device": "ide0-hd1",

               "operation": "write",

               "action": "stop",

-              "__com.redhat_reason": "enospc" },

+              "__com.redhat_reason": "enospc",

+			  "__com.redhat_debug_info": {

+                "message": "No space left on device",

+				"errno": 28 } }

     "timestamp": { "seconds": 1265044230, "microseconds": 450486 } }

 Note: If action is "stop", a STOP event will eventually follow the

diff --git a/qapi/block-core.json b/qapi/block-core.json

index 404059b..706c5d9 100644

--- a/qapi/block-core.json

+++ b/qapi/block-core.json

@@ -1505,6 +1505,17 @@

   'data': [ 'enospc', 'eperm', 'eio', 'eother' ] }

 ##

+# @RHEL7BlockErrorDebugInfo

+#

+# Debug information for a block I/O error

+#

+# @message: error message returned by strerror()

+# @errno: errno value

+##

+{ 'type': 'RHEL7BlockErrorDebugInfo',

+  'data': { 'message': 'str', 'errno': 'int' } }

+

+##

 # @BLOCK_IMAGE_CORRUPTED

 #

 # Emitted when a disk image is being marked corrupt

@@ -1542,6 +1553,10 @@

 #

 # @__com.redhat_reason: error reason (RHEL7 vendor extension)

 #

+# @__com.redhat_debug_info: debug information for humans, applications

+#                           should NOT read any information from this

+#                           member (RHEL7 vendor extension)

+#

 # Note: If action is "stop", a STOP event will eventually follow the

 # BLOCK_IO_ERROR event

 #

@@ -1550,7 +1565,8 @@

 { 'event': 'BLOCK_IO_ERROR',

   'data': { 'device': 'str', 'operation': 'IoOperationType',

             'action': 'BlockErrorAction',

-            '__com.redhat_reason': 'RHEL7BlockErrorReason' } }

+            '__com.redhat_reason': 'RHEL7BlockErrorReason',

+            '__com.redhat_debug_info': 'RHEL7BlockErrorDebugInfo' } }

 ##

 # @BLOCK_JOB_COMPLETED