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authorFam Zheng <famz@redhat.com>2015-04-03 22:05:18 +0800
committerKevin Wolf <kwolf@redhat.com>2015-04-28 15:36:09 +0200
commit751ebd76e654bd1e65da08ecf694325282b4cfcc (patch)
treee4a1a824f63fc24501480faec35a388c7df22f18 /blockjob.c
parent199667a8c843d268f0fe80f09041b8c7193f1ba5 (diff)
downloadqemu-arm-751ebd76e654bd1e65da08ecf694325282b4cfcc.tar.gz
blockjob: Allow nested pause
This patch changes block_job_pause to increase the pause counter and block_job_resume to decrease it. The counter will allow calling block_job_pause/block_job_resume unconditionally on a job when we need to suspend the IO temporarily. From now on, each block_job_resume must be paired with a block_job_pause to keep the counter balanced. The user pause from QMP or HMP will only trigger block_job_pause once until it's resumed, this is achieved by adding a user_paused flag in BlockJob. One occurrence of block_job_resume in mirror_complete is replaced with block_job_enter which does what is necessary. In block_job_cancel, the cancel flag is good enough to instruct coroutines to quit loop, so use block_job_enter to replace the unpaired block_job_resume. Upon block job IO error, user is notified about the entering to the pause state, so this pause belongs to user pause, set the flag accordingly and expect a matching QMP resume. [Extended doc comments as suggested by Paolo Bonzini <pbonzini@redhat.com>. --Stefan] Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 1428069921-2957-2-git-send-email-famz@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'blockjob.c')
-rw-r--r--blockjob.c23
1 files changed, 17 insertions, 6 deletions
diff --git a/blockjob.c b/blockjob.c
index ba2255d91f..2755465259 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -107,7 +107,7 @@ void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
void block_job_complete(BlockJob *job, Error **errp)
{
- if (job->paused || job->cancelled || !job->driver->complete) {
+ if (job->pause_count || job->cancelled || !job->driver->complete) {
error_set(errp, QERR_BLOCK_JOB_NOT_READY,
bdrv_get_device_name(job->bs));
return;
@@ -118,17 +118,26 @@ void block_job_complete(BlockJob *job, Error **errp)
void block_job_pause(BlockJob *job)
{
- job->paused = true;
+ job->pause_count++;
}
bool block_job_is_paused(BlockJob *job)
{
- return job->paused;
+ return job->pause_count > 0;
}
void block_job_resume(BlockJob *job)
{
- job->paused = false;
+ assert(job->pause_count > 0);
+ job->pause_count--;
+ if (job->pause_count) {
+ return;
+ }
+ block_job_enter(job);
+}
+
+void block_job_enter(BlockJob *job)
+{
block_job_iostatus_reset(job);
if (job->co && !job->busy) {
qemu_coroutine_enter(job->co, NULL);
@@ -138,7 +147,7 @@ void block_job_resume(BlockJob *job)
void block_job_cancel(BlockJob *job)
{
job->cancelled = true;
- block_job_resume(job);
+ block_job_enter(job);
}
bool block_job_is_cancelled(BlockJob *job)
@@ -258,7 +267,7 @@ BlockJobInfo *block_job_query(BlockJob *job)
info->device = g_strdup(bdrv_get_device_name(job->bs));
info->len = job->len;
info->busy = job->busy;
- info->paused = job->paused;
+ info->paused = job->pause_count > 0;
info->offset = job->offset;
info->speed = job->speed;
info->io_status = job->iostatus;
@@ -335,6 +344,8 @@ BlockErrorAction block_job_error_action(BlockJob *job, BlockDriverState *bs,
IO_OPERATION_TYPE_WRITE,
action, &error_abort);
if (action == BLOCK_ERROR_ACTION_STOP) {
+ /* make the pause user visible, which will be resumed from QMP. */
+ job->user_paused = true;
block_job_pause(job);
block_job_iostatus_set_err(job, error);
if (bs != job->bs) {