Commit 882e9b89 authored by Stefan Hajnoczi's avatar Stefan Hajnoczi
Browse files

blockdev: add x-blockdev-set-iothread force boolean 



When a node is already associated with a BlockBackend the
x-blockdev-set-iothread command refuses to set the IOThread.  This is to
prevent accidentally changing the IOThread when the nodes are in use.

When the nodes are created with -drive they automatically get a
BlockBackend.  In that case we know nothing is using them yet and it's
safe to set the IOThread.  Add a force boolean to override the check.

Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarEric Blake <eblake@redhat.com>
Message-id: 20171207201320.19284-4-stefanha@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent d02d8dde

blockdev.c

+6 −5
Original line number Diff line number Diff line
@@ -4131,7 +4131,7 @@ BlockJobInfoList *qmp_query_block_jobs(Error **errp) 
}



void qmp_x_blockdev_set_iothread(const char *node_name, StrOrNull *iothread,

                                 Error **errp)

                                 bool has_force, bool force, Error **errp)

{

    AioContext *old_context;

    AioContext *new_context;
@@ -4143,10 +4143,11 @@ void qmp_x_blockdev_set_iothread(const char *node_name, StrOrNull *iothread, 
        return;

    }



    /* If we want to allow more extreme test scenarios this guard could be

     * removed.  For now it protects against accidents. */

    if (bdrv_has_blk(bs)) {

        error_setg(errp, "Node %s is in use", node_name);

    /* Protects against accidents. */

    if (!(has_force && force) && bdrv_has_blk(bs)) {

        error_setg(errp, "Node %s is associated with a BlockBackend and could "

                         "be in use (use force=true to override this check)",

                         node_name);

        return;

    }

qapi/block-core.json

+5 −1
Original line number Diff line number Diff line
@@ -3962,6 +3962,9 @@ 
#

# @iothread: the name of the IOThread object or null for the main loop

#

# @force: true if the node and its children should be moved when a BlockBackend

#         is already attached

#

# Note: this command is experimental and intended for test cases that need

# control over IOThreads only.

#
@@ -3984,4 +3987,5 @@ 
##

{ 'command': 'x-blockdev-set-iothread',

  'data' : { 'node-name': 'str',

             'iothread': 'StrOrNull' } }
 
             'iothread': 'StrOrNull',

             '*force': 'bool' } }