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mirror: add support for on-source-error/on-target-error

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Error management is important for mirroring; otherwise, an error on the
target (even something as "innocent" as ENOSPC) requires to start again
with a full copy.  Similar to on_read_error/on_write_error, two separate
knobs are provided for on_source_error (reads) and on_target_error (writes).
The default is 'report' for both.

The 'ignore' policy will leave the sector dirty, so that it will be
retried later.  Thus, it will not cause corruption.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Paolo Bonzini 2012-10-18 16:49:28 +02:00 • committed by Kevin Wolf
parent 3bd293c3fd
commit b952b5589a
6 changed files with 107 additions and 25 deletions
Download patch file Download diff file Expand all files Collapse all files

92
block/mirror.c
View file

@ -32,13 +32,28 @@ typedef struct MirrorBlockJob {
RateLimit limit;
BlockDriverState *target;
MirrorSyncMode mode;
BlockdevOnError on_source_error, on_target_error;
bool synced;
bool should_complete;
int64_t sector_num;
uint8_t *buf;
} MirrorBlockJob;
static int coroutine_fn mirror_iteration(MirrorBlockJob *s)
static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read,
int error)
{
s->synced = false;
if (read) {
return block_job_error_action(&s->common, s->common.bs,
s->on_source_error, true, error);
} else {
return block_job_error_action(&s->common, s->target,
s->on_target_error, false, error);
}
}
static int coroutine_fn mirror_iteration(MirrorBlockJob *s,
BlockErrorAction *p_action)
{
BlockDriverState *source = s->common.bs;
BlockDriverState *target = s->target;
@ -60,9 +75,21 @@ static int coroutine_fn mirror_iteration(MirrorBlockJob *s)
trace_mirror_one_iteration(s, s->sector_num, nb_sectors);
ret = bdrv_co_readv(source, s->sector_num, nb_sectors, &qiov);
if (ret < 0) {
return ret;
*p_action = mirror_error_action(s, true, -ret);
goto fail;
}
return bdrv_co_writev(target, s->sector_num, nb_sectors, &qiov);
ret = bdrv_co_writev(target, s->sector_num, nb_sectors, &qiov);
if (ret < 0) {
*p_action = mirror_error_action(s, false, -ret);
s->synced = false;
goto fail;
}
return 0;
fail:
/* Try again later. */
bdrv_set_dirty(source, s->sector_num, nb_sectors);
return ret;
}
static void coroutine_fn mirror_run(void *opaque)
@ -117,8 +144,9 @@ static void coroutine_fn mirror_run(void *opaque)
cnt = bdrv_get_dirty_count(bs);
if (cnt != 0) {
ret = mirror_iteration(s);
if (ret < 0) {
BlockErrorAction action = BDRV_ACTION_REPORT;
ret = mirror_iteration(s, &action);
if (ret < 0 && action == BDRV_ACTION_REPORT) {
goto immediate_exit;
}
cnt = bdrv_get_dirty_count(bs);
@ -129,23 +157,25 @@ static void coroutine_fn mirror_run(void *opaque)
trace_mirror_before_flush(s);
ret = bdrv_flush(s->target);
if (ret < 0) {
goto immediate_exit;
}
if (mirror_error_action(s, false, -ret) == BDRV_ACTION_REPORT) {
goto immediate_exit;
}
} else {
/* We're out of the streaming phase. From now on, if the job
* is cancelled we will actually complete all pending I/O and
* report completion. This way, block-job-cancel will leave
* the target in a consistent state.
*/
s->common.offset = end * BDRV_SECTOR_SIZE;
if (!s->synced) {
block_job_ready(&s->common);
s->synced = true;
}
/* We're out of the streaming phase. From now on, if the job
* is cancelled we will actually complete all pending I/O and
* report completion. This way, block-job-cancel will leave
* the target in a consistent state.
*/
s->common.offset = end * BDRV_SECTOR_SIZE;
if (!s->synced) {
block_job_ready(&s->common);
s->synced = true;
should_complete = s->should_complete ||
block_job_is_cancelled(&s->common);
cnt = bdrv_get_dirty_count(bs);
}
should_complete = s->should_complete ||
block_job_is_cancelled(&s->common);
cnt = bdrv_get_dirty_count(bs);
}
if (cnt == 0 && should_complete) {
@ -197,6 +227,7 @@ static void coroutine_fn mirror_run(void *opaque)
immediate_exit:
g_free(s->buf);
bdrv_set_dirty_tracking(bs, false);
bdrv_iostatus_disable(s->target);
if (s->should_complete && ret == 0) {
if (bdrv_get_flags(s->target) != bdrv_get_flags(s->common.bs)) {
bdrv_reopen(s->target, bdrv_get_flags(s->common.bs), NULL);
@ -219,6 +250,13 @@ static void mirror_set_speed(BlockJob *job, int64_t speed, Error **errp)
ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME);
}
static void mirror_iostatus_reset(BlockJob *job)
{
MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
bdrv_iostatus_reset(s->target);
}
static void mirror_complete(BlockJob *job, Error **errp)
{
MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
@ -245,25 +283,39 @@ static BlockJobType mirror_job_type = {
.instance_size = sizeof(MirrorBlockJob),
.job_type = "mirror",
.set_speed = mirror_set_speed,
.iostatus_reset= mirror_iostatus_reset,
.complete = mirror_complete,
};
void mirror_start(BlockDriverState *bs, BlockDriverState *target,
int64_t speed, MirrorSyncMode mode,
BlockdevOnError on_source_error,
BlockdevOnError on_target_error,
BlockDriverCompletionFunc *cb,
void *opaque, Error **errp)
{
MirrorBlockJob *s;
if ((on_source_error == BLOCKDEV_ON_ERROR_STOP ||
on_source_error == BLOCKDEV_ON_ERROR_ENOSPC) &&
!bdrv_iostatus_is_enabled(bs)) {
error_set(errp, QERR_INVALID_PARAMETER, "on-source-error");
return;
}
s = block_job_create(&mirror_job_type, bs, speed, cb, opaque, errp);
if (!s) {
return;
}
s->on_source_error = on_source_error;
s->on_target_error = on_target_error;
s->target = target;
s->mode = mode;
bdrv_set_dirty_tracking(bs, true);
bdrv_set_enable_write_cache(s->target, true);
bdrv_set_on_error(s->target, on_target_error, on_target_error);
bdrv_iostatus_enable(s->target);
s->common.co = qemu_coroutine_create(mirror_run);
trace_mirror_start(bs, s, s->common.co, opaque);
qemu_coroutine_enter(s->common.co, s);