From 60b62c9d02e5e19e4cfa6eaeb6652339d4c4ede5 Mon Sep 17 00:00:00 2001
From: Markus Armbruster <armbru@redhat.com>
Date: Tue, 14 Mar 2017 14:03:39 +0100
Subject: QMP: Forward-port __com.redhat_drive_del from RHEL-6

RH-Author: Markus Armbruster <armbru@redhat.com>
Message-id: <1387262799-10350-3-git-send-email-armbru@redhat.com>
Patchwork-id: 56292
O-Subject: [PATCH v2 2/6] QMP: Forward-port __com.redhat_drive_del from RHEL-6
Bugzilla: 889051
RH-Acked-by: Fam Zheng <famz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Luiz Capitulino <lcapitulino@redhat.com>

From: Markus Armbruster <armbru@redhat.com>

Upstream has drive_del, but only in HMP.  The backport to RHEL-6 added
it to QMP as well.  Since the QMP command is a downstream extension,
it needs the __com.redhat_ prefix.  Since RHEL-6 doesn't have separate
definition of QMP and HMP commands, both the QMP and the HMP command
got the prefix.

RHEL-7 inherits HMP command drive_del from upstream.  Add QMP command
__com.redhat_drive_del for RHEL-6 compatibility.

If we needed similar compatibility for the HMP command, we'd have to
add __com.redhat_drive_del as alias for drive_del.  But we don't.

Code copied from RHEL-6's qemu-monitor.hx as of
qemu-kvm-0.12.1.2-2.418.el6.  It has a "drive_del" without the prefix
in the documentation.  Fixed here.  Hardly worth fixing in RHEL-6 now.

Signed-off-by: Markus Armbruster <armbru@redhat.com>

Rebase notes (2.9.0):
- documentation moved from docs/qmp-commands.txt to qapi/block.json
- replace qmp_x_blockdev_del with qmp_blockdev_del (due to 79b7a77)

Rebase notes (2.8.0):
- qmp-commands.hx replaced by docs/qmp-commands.txt (commit bd6092e)
- Changed qmp_x_blockdev_del arguments (upstream)

Rebase notes (2.4.0):
- use traditional cmd for qmp
- remove user_print

Merged patches (2.9.0):
- 4831182 QMP: Fix forward port of __com.redhat_drive_del

Merged patches (2.7.0):
- 85786e0 Fix crash with __com.redhat_drive_del

(cherry picked from commit b7a0cafd6494cd3855fe10934314b6b1d2df5d2d)
---
 blockdev.c      | 28 ++++++++++++++++------------
 qapi/block.json | 23 +++++++++++++++++++++++
 2 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/blockdev.c b/blockdev.c
index 02cd69b..d5e8ee3 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -2854,32 +2854,27 @@ BlockDirtyBitmapSha256 *qmp_x_debug_block_dirty_bitmap_sha256(const char *node,
     return ret;
 }
 
-void hmp_drive_del(Monitor *mon, const QDict *qdict)
+void qmp___com_redhat_drive_del(const char *id, Error **errp)
 {
-    const char *id = qdict_get_str(qdict, "id");
     BlockBackend *blk;
     BlockDriverState *bs;
     AioContext *aio_context;
-    Error *local_err = NULL;
 
     bs = bdrv_find_node(id);
     if (bs) {
-        qmp_blockdev_del(id, &local_err);
-        if (local_err) {
-            error_report_err(local_err);
-        }
+        qmp_blockdev_del(id, errp);
         return;
     }
 
     blk = blk_by_name(id);
     if (!blk) {
-        error_report("Device '%s' not found", id);
+        error_setg(errp, "Device '%s' not found", id);
         return;
     }
 
     if (!blk_legacy_dinfo(blk)) {
-        error_report("Deleting device added with blockdev-add"
-                     " is not supported");
+        error_setg(errp, "Deleting device added with blockdev-add"
+                         " is not supported");
         return;
     }
 
@@ -2888,8 +2883,7 @@ void hmp_drive_del(Monitor *mon, const QDict *qdict)
 
     bs = blk_bs(blk);
     if (bs) {
-        if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_DRIVE_DEL, &local_err)) {
-            error_report_err(local_err);
+        if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_DRIVE_DEL, errp)) {
             aio_context_release(aio_context);
             return;
         }
@@ -2914,6 +2908,16 @@ void hmp_drive_del(Monitor *mon, const QDict *qdict)
     aio_context_release(aio_context);
 }
 
+void hmp_drive_del(Monitor *mon, const QDict *qdict)
+{
+    Error *local_err = NULL;
+
+    qmp___com_redhat_drive_del(qdict_get_str(qdict, "id"), &local_err);
+    if (local_err) {
+        error_report_err(local_err);
+    }
+}
+
 void qmp_block_resize(bool has_device, const char *device,
                       bool has_node_name, const char *node_name,
                       int64_t size, Error **errp)
diff --git a/qapi/block.json b/qapi/block.json
index 414b61b..03115d3 100644
--- a/qapi/block.json
+++ b/qapi/block.json
@@ -189,6 +189,29 @@
             '*force': 'bool' } }
 
 ##
+# @__com.redhat_drive_del:
+#
+# Remove host block device.
+#
+# Remove host block device.  The result is that guest generated IO is no longer
+# submitted against the host device underlying the disk.  Once a drive has
+# been deleted, the QEMU Block layer returns -EIO which results in IO
+# errors in the guest for applications that are reading/writing to the device.
+# These errors are always reported to the guest, regardless of the drive's error
+# actions (drive options rerror, werror).
+# 
+# @id: the device's ID
+#
+# Example:
+#
+# -> { "execute": "__com.redhat_drive_del", "arguments": { "id": "block1" } }
+# <- { "return": {} }
+#
+##
+{ 'command': '__com.redhat_drive_del',
+  'data': { 'id': 'str' } }
+
+##
 # @nbd-server-start:
 #
 # Start an NBD server listening on the given host and port.  Block
-- 
1.8.3.1