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qemu-e2k/block/mirror.c
Kevin Wolf 3f09bfbc7b block: Add and use bdrv_replace_in_backing_chain() 
This cleans up the mess we left behind in the mirror code after the
previous patch. Instead of using bdrv_swap(), just change pointers.

The interface change of the mirror job that callers must consider is
that after job completion, their local BDS pointers still point to the
same node now. qemu-img must change its code accordingly (which makes it
easier to understand); the other callers stays unchanged because after
completion they don't do anything with the BDS, but just with the job,
and the job is still owned by the source BDS.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-10-16 15:34:30 +02:00

833 lines
27 KiB
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/*
* Image mirroring
*
* Copyright Red Hat, Inc. 2012
*
* Authors:
* Paolo Bonzini <pbonzini@redhat.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
#include "trace.h"
#include "block/blockjob.h"
#include "block/block_int.h"
#include "qapi/qmp/qerror.h"
#include "qemu/ratelimit.h"
#include "qemu/bitmap.h"
#define SLICE_TIME 100000000ULL /* ns */
#define MAX_IN_FLIGHT 16
#define DEFAULT_MIRROR_BUF_SIZE (10 << 20)
/* The mirroring buffer is a list of granularity-sized chunks.
* Free chunks are organized in a list.
*/
typedef struct MirrorBuffer {
QSIMPLEQ_ENTRY(MirrorBuffer) next;
} MirrorBuffer;
typedef struct MirrorBlockJob {
BlockJob common;
RateLimit limit;
BlockDriverState *target;
BlockDriverState *base;
/* The name of the graph node to replace */
char *replaces;
/* The BDS to replace */
BlockDriverState *to_replace;
/* Used to block operations on the drive-mirror-replace target */
Error *replace_blocker;
bool is_none_mode;
BlockdevOnError on_source_error, on_target_error;
bool synced;
bool should_complete;
int64_t sector_num;
int64_t granularity;
size_t buf_size;
int64_t bdev_length;
unsigned long *cow_bitmap;
BdrvDirtyBitmap *dirty_bitmap;
HBitmapIter hbi;
uint8_t *buf;
QSIMPLEQ_HEAD(, MirrorBuffer) buf_free;
int buf_free_count;
unsigned long *in_flight_bitmap;
int in_flight;
int sectors_in_flight;
int ret;
bool unmap;
bool waiting_for_io;
} MirrorBlockJob;
typedef struct MirrorOp {
MirrorBlockJob *s;
QEMUIOVector qiov;
int64_t sector_num;
int nb_sectors;
} MirrorOp;
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 void mirror_iteration_done(MirrorOp *op, int ret)
{
MirrorBlockJob *s = op->s;
struct iovec *iov;
int64_t chunk_num;
int i, nb_chunks, sectors_per_chunk;
trace_mirror_iteration_done(s, op->sector_num, op->nb_sectors, ret);
s->in_flight--;
s->sectors_in_flight -= op->nb_sectors;
iov = op->qiov.iov;
for (i = 0; i < op->qiov.niov; i++) {
MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base;
QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next);
s->buf_free_count++;
}
sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
chunk_num = op->sector_num / sectors_per_chunk;
nb_chunks = op->nb_sectors / sectors_per_chunk;
bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks);
if (ret >= 0) {
if (s->cow_bitmap) {
bitmap_set(s->cow_bitmap, chunk_num, nb_chunks);
}
s->common.offset += (uint64_t)op->nb_sectors * BDRV_SECTOR_SIZE;
}
qemu_iovec_destroy(&op->qiov);
g_free(op);
if (s->waiting_for_io) {
qemu_coroutine_enter(s->common.co, NULL);
}
}
static void mirror_write_complete(void *opaque, int ret)
{
MirrorOp *op = opaque;
MirrorBlockJob *s = op->s;
if (ret < 0) {
BlockErrorAction action;
bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors);
action = mirror_error_action(s, false, -ret);
if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) {
s->ret = ret;
}
}
mirror_iteration_done(op, ret);
}
static void mirror_read_complete(void *opaque, int ret)
{
MirrorOp *op = opaque;
MirrorBlockJob *s = op->s;
if (ret < 0) {
BlockErrorAction action;
bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors);
action = mirror_error_action(s, true, -ret);
if (action == BLOCK_ERROR_ACTION_REPORT && s->ret >= 0) {
s->ret = ret;
}
mirror_iteration_done(op, ret);
return;
}
bdrv_aio_writev(s->target, op->sector_num, &op->qiov, op->nb_sectors,
mirror_write_complete, op);
}
static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
{
BlockDriverState *source = s->common.bs;
int nb_sectors, sectors_per_chunk, nb_chunks;
int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector;
uint64_t delay_ns = 0;
MirrorOp *op;
int pnum;
int64_t ret;
s->sector_num = hbitmap_iter_next(&s->hbi);
if (s->sector_num < 0) {
bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
s->sector_num = hbitmap_iter_next(&s->hbi);
trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap));
assert(s->sector_num >= 0);
}
hbitmap_next_sector = s->sector_num;
sector_num = s->sector_num;
sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
end = s->bdev_length / BDRV_SECTOR_SIZE;
/* Extend the QEMUIOVector to include all adjacent blocks that will
* be copied in this operation.
*
* We have to do this if we have no backing file yet in the destination,
* and the cluster size is very large. Then we need to do COW ourselves.
* The first time a cluster is copied, copy it entirely. Note that,
* because both the granularity and the cluster size are powers of two,
* the number of sectors to copy cannot exceed one cluster.
*
* We also want to extend the QEMUIOVector to include more adjacent
* dirty blocks if possible, to limit the number of I/O operations and
* run efficiently even with a small granularity.
*/
nb_chunks = 0;
nb_sectors = 0;
next_sector = sector_num;
next_chunk = sector_num / sectors_per_chunk;
/* Wait for I/O to this cluster (from a previous iteration) to be done. */
while (test_bit(next_chunk, s->in_flight_bitmap)) {
trace_mirror_yield_in_flight(s, sector_num, s->in_flight);
s->waiting_for_io = true;
qemu_coroutine_yield();
s->waiting_for_io = false;
}
do {
int added_sectors, added_chunks;
if (!bdrv_get_dirty(source, s->dirty_bitmap, next_sector) ||
test_bit(next_chunk, s->in_flight_bitmap)) {
assert(nb_sectors > 0);
break;
}
added_sectors = sectors_per_chunk;
if (s->cow_bitmap && !test_bit(next_chunk, s->cow_bitmap)) {
bdrv_round_to_clusters(s->target,
next_sector, added_sectors,
&next_sector, &added_sectors);
/* On the first iteration, the rounding may make us copy
* sectors before the first dirty one.
*/
if (next_sector < sector_num) {
assert(nb_sectors == 0);
sector_num = next_sector;
next_chunk = next_sector / sectors_per_chunk;
}
}
added_sectors = MIN(added_sectors, end - (sector_num + nb_sectors));
added_chunks = (added_sectors + sectors_per_chunk - 1) / sectors_per_chunk;
/* When doing COW, it may happen that there is not enough space for
* a full cluster. Wait if that is the case.
*/
while (nb_chunks == 0 && s->buf_free_count < added_chunks) {
trace_mirror_yield_buf_busy(s, nb_chunks, s->in_flight);
s->waiting_for_io = true;
qemu_coroutine_yield();
s->waiting_for_io = false;
}
if (s->buf_free_count < nb_chunks + added_chunks) {
trace_mirror_break_buf_busy(s, nb_chunks, s->in_flight);
break;
}
if (IOV_MAX < nb_chunks + added_chunks) {
trace_mirror_break_iov_max(s, nb_chunks, added_chunks);
break;
}
/* We have enough free space to copy these sectors. */
bitmap_set(s->in_flight_bitmap, next_chunk, added_chunks);
nb_sectors += added_sectors;
nb_chunks += added_chunks;
next_sector += added_sectors;
next_chunk += added_chunks;
if (!s->synced && s->common.speed) {
delay_ns = ratelimit_calculate_delay(&s->limit, added_sectors);
}
} while (delay_ns == 0 && next_sector < end);
/* Allocate a MirrorOp that is used as an AIO callback. */
op = g_new(MirrorOp, 1);
op->s = s;
op->sector_num = sector_num;
op->nb_sectors = nb_sectors;
/* Now make a QEMUIOVector taking enough granularity-sized chunks
* from s->buf_free.
*/
qemu_iovec_init(&op->qiov, nb_chunks);
next_sector = sector_num;
while (nb_chunks-- > 0) {
MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free);
size_t remaining = (nb_sectors * BDRV_SECTOR_SIZE) - op->qiov.size;
QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next);
s->buf_free_count--;
qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining));
/* Advance the HBitmapIter in parallel, so that we do not examine
* the same sector twice.
*/
if (next_sector > hbitmap_next_sector
&& bdrv_get_dirty(source, s->dirty_bitmap, next_sector)) {
hbitmap_next_sector = hbitmap_iter_next(&s->hbi);
}
next_sector += sectors_per_chunk;
}
bdrv_reset_dirty_bitmap(s->dirty_bitmap, sector_num, nb_sectors);
/* Copy the dirty cluster. */
s->in_flight++;
s->sectors_in_flight += nb_sectors;
trace_mirror_one_iteration(s, sector_num, nb_sectors);
ret = bdrv_get_block_status_above(source, NULL, sector_num,
nb_sectors, &pnum);
if (ret < 0 || pnum < nb_sectors ||
(ret & BDRV_BLOCK_DATA && !(ret & BDRV_BLOCK_ZERO))) {
bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors,
mirror_read_complete, op);
} else if (ret & BDRV_BLOCK_ZERO) {
bdrv_aio_write_zeroes(s->target, sector_num, op->nb_sectors,
s->unmap ? BDRV_REQ_MAY_UNMAP : 0,
mirror_write_complete, op);
} else {
assert(!(ret & BDRV_BLOCK_DATA));
bdrv_aio_discard(s->target, sector_num, op->nb_sectors,
mirror_write_complete, op);
}
return delay_ns;
}
static void mirror_free_init(MirrorBlockJob *s)
{
int granularity = s->granularity;
size_t buf_size = s->buf_size;
uint8_t *buf = s->buf;
assert(s->buf_free_count == 0);
QSIMPLEQ_INIT(&s->buf_free);
while (buf_size != 0) {
MirrorBuffer *cur = (MirrorBuffer *)buf;
QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next);
s->buf_free_count++;
buf_size -= granularity;
buf += granularity;
}
}
static void mirror_drain(MirrorBlockJob *s)
{
while (s->in_flight > 0) {
s->waiting_for_io = true;
qemu_coroutine_yield();
s->waiting_for_io = false;
}
}
typedef struct {
int ret;
} MirrorExitData;
static void mirror_exit(BlockJob *job, void *opaque)
{
MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
MirrorExitData *data = opaque;
AioContext *replace_aio_context = NULL;
BlockDriverState *src = s->common.bs;
/* Make sure that the source BDS doesn't go away before we called
* block_job_completed(). */
bdrv_ref(src);
if (s->to_replace) {
replace_aio_context = bdrv_get_aio_context(s->to_replace);
aio_context_acquire(replace_aio_context);
}
if (s->should_complete && data->ret == 0) {
BlockDriverState *to_replace = s->common.bs;
if (s->to_replace) {
to_replace = s->to_replace;
}
if (bdrv_get_flags(s->target) != bdrv_get_flags(to_replace)) {
bdrv_reopen(s->target, bdrv_get_flags(to_replace), NULL);
}
bdrv_replace_in_backing_chain(to_replace, s->target);
}
if (s->to_replace) {
bdrv_op_unblock_all(s->to_replace, s->replace_blocker);
error_free(s->replace_blocker);
bdrv_unref(s->to_replace);
}
if (replace_aio_context) {
aio_context_release(replace_aio_context);
}
g_free(s->replaces);
bdrv_unref(s->target);
block_job_completed(&s->common, data->ret);
g_free(data);
bdrv_unref(src);
}
static void coroutine_fn mirror_run(void *opaque)
{
MirrorBlockJob *s = opaque;
MirrorExitData *data;
BlockDriverState *bs = s->common.bs;
int64_t sector_num, end, length;
uint64_t last_pause_ns;
BlockDriverInfo bdi;
char backing_filename[2]; /* we only need 2 characters because we are only
checking for a NULL string */
int ret = 0;
int n;
if (block_job_is_cancelled(&s->common)) {
goto immediate_exit;
}
s->bdev_length = bdrv_getlength(bs);
if (s->bdev_length < 0) {
ret = s->bdev_length;
goto immediate_exit;
} else if (s->bdev_length == 0) {
/* Report BLOCK_JOB_READY and wait for complete. */
block_job_event_ready(&s->common);
s->synced = true;
while (!block_job_is_cancelled(&s->common) && !s->should_complete) {
block_job_yield(&s->common);
}
s->common.cancelled = false;
goto immediate_exit;
}
length = DIV_ROUND_UP(s->bdev_length, s->granularity);
s->in_flight_bitmap = bitmap_new(length);
/* If we have no backing file yet in the destination, we cannot let
* the destination do COW. Instead, we copy sectors around the
* dirty data if needed. We need a bitmap to do that.
*/
bdrv_get_backing_filename(s->target, backing_filename,
sizeof(backing_filename));
if (backing_filename[0] && !s->target->backing) {
ret = bdrv_get_info(s->target, &bdi);
if (ret < 0) {
goto immediate_exit;
}
if (s->granularity < bdi.cluster_size) {
s->buf_size = MAX(s->buf_size, bdi.cluster_size);
s->cow_bitmap = bitmap_new(length);
}
}
end = s->bdev_length / BDRV_SECTOR_SIZE;
s->buf = qemu_try_blockalign(bs, s->buf_size);
if (s->buf == NULL) {
ret = -ENOMEM;
goto immediate_exit;
}
mirror_free_init(s);
last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
if (!s->is_none_mode) {
/* First part, loop on the sectors and initialize the dirty bitmap. */
BlockDriverState *base = s->base;
bool mark_all_dirty = s->base == NULL && !bdrv_has_zero_init(s->target);
for (sector_num = 0; sector_num < end; ) {
/* Just to make sure we are not exceeding int limit. */
int nb_sectors = MIN(INT_MAX >> BDRV_SECTOR_BITS,
end - sector_num);
int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
if (now - last_pause_ns > SLICE_TIME) {
last_pause_ns = now;
block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, 0);
}
if (block_job_is_cancelled(&s->common)) {
goto immediate_exit;
}
ret = bdrv_is_allocated_above(bs, base, sector_num, nb_sectors, &n);
if (ret < 0) {
goto immediate_exit;
}
assert(n > 0);
if (ret == 1 || mark_all_dirty) {
bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n);
}
sector_num += n;
}
}
bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi);
for (;;) {
uint64_t delay_ns = 0;
int64_t cnt;
bool should_complete;
if (s->ret < 0) {
ret = s->ret;
goto immediate_exit;
}
cnt = bdrv_get_dirty_count(s->dirty_bitmap);
/* s->common.offset contains the number of bytes already processed so
* far, cnt is the number of dirty sectors remaining and
* s->sectors_in_flight is the number of sectors currently being
* processed; together those are the current total operation length */
s->common.len = s->common.offset +
(cnt + s->sectors_in_flight) * BDRV_SECTOR_SIZE;
/* Note that even when no rate limit is applied we need to yield
* periodically with no pending I/O so that bdrv_drain_all() returns.
* We do so every SLICE_TIME nanoseconds, or when there is an error,
* or when the source is clean, whichever comes first.
*/
if (qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - last_pause_ns < SLICE_TIME &&
s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
if (s->in_flight == MAX_IN_FLIGHT || s->buf_free_count == 0 ||
(cnt == 0 && s->in_flight > 0)) {
trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt);
s->waiting_for_io = true;
qemu_coroutine_yield();
s->waiting_for_io = false;
continue;
} else if (cnt != 0) {
delay_ns = mirror_iteration(s);
}
}
should_complete = false;
if (s->in_flight == 0 && cnt == 0) {
trace_mirror_before_flush(s);
ret = bdrv_flush(s->target);
if (ret < 0) {
if (mirror_error_action(s, false, -ret) ==
BLOCK_ERROR_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.
*/
if (!s->synced) {
block_job_event_ready(&s->common);
s->synced = true;
}
should_complete = s->should_complete ||
block_job_is_cancelled(&s->common);
cnt = bdrv_get_dirty_count(s->dirty_bitmap);
}
}
if (cnt == 0 && should_complete) {
/* The dirty bitmap is not updated while operations are pending.
* If we're about to exit, wait for pending operations before
* calling bdrv_get_dirty_count(bs), or we may exit while the
* source has dirty data to copy!
*
* Note that I/O can be submitted by the guest while
* mirror_populate runs.
*/
trace_mirror_before_drain(s, cnt);
bdrv_drain(bs);
cnt = bdrv_get_dirty_count(s->dirty_bitmap);
}
ret = 0;
trace_mirror_before_sleep(s, cnt, s->synced, delay_ns);
if (!s->synced) {
block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
if (block_job_is_cancelled(&s->common)) {
break;
}
} else if (!should_complete) {
delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0);
block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
} else if (cnt == 0) {
/* The two disks are in sync. Exit and report successful
* completion.
*/
assert(QLIST_EMPTY(&bs->tracked_requests));
s->common.cancelled = false;
break;
}
last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
}
immediate_exit:
if (s->in_flight > 0) {
/* We get here only if something went wrong. Either the job failed,
* or it was cancelled prematurely so that we do not guarantee that
* the target is a copy of the source.
*/
assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common)));
mirror_drain(s);
}
assert(s->in_flight == 0);
qemu_vfree(s->buf);
g_free(s->cow_bitmap);
g_free(s->in_flight_bitmap);
bdrv_release_dirty_bitmap(bs, s->dirty_bitmap);
bdrv_iostatus_disable(s->target);
data = g_malloc(sizeof(*data));
data->ret = ret;
block_job_defer_to_main_loop(&s->common, mirror_exit, data);
}
static void mirror_set_speed(BlockJob *job, int64_t speed, Error **errp)
{
MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
if (speed < 0) {
error_setg(errp, QERR_INVALID_PARAMETER, "speed");
return;
}
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);
Error *local_err = NULL;
int ret;
ret = bdrv_open_backing_file(s->target, NULL, &local_err);
if (ret < 0) {
error_propagate(errp, local_err);
return;
}
if (!s->synced) {
error_setg(errp, QERR_BLOCK_JOB_NOT_READY, job->id);
return;
}
/* check the target bs is not blocked and block all operations on it */
if (s->replaces) {
AioContext *replace_aio_context;
s->to_replace = bdrv_find_node(s->replaces);
if (!s->to_replace) {
error_setg(errp, "Node name '%s' not found", s->replaces);
return;
}
replace_aio_context = bdrv_get_aio_context(s->to_replace);
aio_context_acquire(replace_aio_context);
error_setg(&s->replace_blocker,
"block device is in use by block-job-complete");
bdrv_op_block_all(s->to_replace, s->replace_blocker);
bdrv_ref(s->to_replace);
aio_context_release(replace_aio_context);
}
s->should_complete = true;
block_job_enter(&s->common);
}
static const BlockJobDriver mirror_job_driver = {
.instance_size = sizeof(MirrorBlockJob),
.job_type = BLOCK_JOB_TYPE_MIRROR,
.set_speed = mirror_set_speed,
.iostatus_reset= mirror_iostatus_reset,
.complete = mirror_complete,
};
static const BlockJobDriver commit_active_job_driver = {
.instance_size = sizeof(MirrorBlockJob),
.job_type = BLOCK_JOB_TYPE_COMMIT,
.set_speed = mirror_set_speed,
.iostatus_reset
= mirror_iostatus_reset,
.complete = mirror_complete,
};
static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target,
const char *replaces,
int64_t speed, uint32_t granularity,
int64_t buf_size,
BlockdevOnError on_source_error,
BlockdevOnError on_target_error,
bool unmap,
BlockCompletionFunc *cb,
void *opaque, Error **errp,
const BlockJobDriver *driver,
bool is_none_mode, BlockDriverState *base)
{
MirrorBlockJob *s;
if (granularity == 0) {
granularity = bdrv_get_default_bitmap_granularity(target);
}
assert ((granularity & (granularity - 1)) == 0);
if ((on_source_error == BLOCKDEV_ON_ERROR_STOP ||
on_source_error == BLOCKDEV_ON_ERROR_ENOSPC) &&
!bdrv_iostatus_is_enabled(bs)) {
error_setg(errp, QERR_INVALID_PARAMETER, "on-source-error");
return;
}
if (buf_size < 0) {
error_setg(errp, "Invalid parameter 'buf-size'");
return;
}
if (buf_size == 0) {
buf_size = DEFAULT_MIRROR_BUF_SIZE;
}
s = block_job_create(driver, bs, speed, cb, opaque, errp);
if (!s) {
return;
}
s->replaces = g_strdup(replaces);
s->on_source_error = on_source_error;
s->on_target_error = on_target_error;
s->target = target;
s->is_none_mode = is_none_mode;
s->base = base;
s->granularity = granularity;
s->buf_size = ROUND_UP(buf_size, granularity);
s->unmap = unmap;
s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp);
if (!s->dirty_bitmap) {
g_free(s->replaces);
block_job_release(bs);
return;
}
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);
}
void mirror_start(BlockDriverState *bs, BlockDriverState *target,
const char *replaces,
int64_t speed, uint32_t granularity, int64_t buf_size,
MirrorSyncMode mode, BlockdevOnError on_source_error,
BlockdevOnError on_target_error,
bool unmap,
BlockCompletionFunc *cb,
void *opaque, Error **errp)
{
bool is_none_mode;
BlockDriverState *base;
if (mode == MIRROR_SYNC_MODE_INCREMENTAL) {
error_setg(errp, "Sync mode 'incremental' not supported");
return;
}
is_none_mode = mode == MIRROR_SYNC_MODE_NONE;
base = mode == MIRROR_SYNC_MODE_TOP ? backing_bs(bs) : NULL;
mirror_start_job(bs, target, replaces,
speed, granularity, buf_size,
on_source_error, on_target_error, unmap, cb, opaque, errp,
&mirror_job_driver, is_none_mode, base);
}
void commit_active_start(BlockDriverState *bs, BlockDriverState *base,
int64_t speed,
BlockdevOnError on_error,
BlockCompletionFunc *cb,
void *opaque, Error **errp)
{
int64_t length, base_length;
int orig_base_flags;
int ret;
Error *local_err = NULL;
orig_base_flags = bdrv_get_flags(base);
if (bdrv_reopen(base, bs->open_flags, errp)) {
return;
}
length = bdrv_getlength(bs);
if (length < 0) {
error_setg_errno(errp, -length,
"Unable to determine length of %s", bs->filename);
goto error_restore_flags;
}
base_length = bdrv_getlength(base);
if (base_length < 0) {
error_setg_errno(errp, -base_length,
"Unable to determine length of %s", base->filename);
goto error_restore_flags;
}
if (length > base_length) {
ret = bdrv_truncate(base, length);
if (ret < 0) {
error_setg_errno(errp, -ret,
"Top image %s is larger than base image %s, and "
"resize of base image failed",
bs->filename, base->filename);
goto error_restore_flags;
}
}
bdrv_ref(base);
mirror_start_job(bs, base, NULL, speed, 0, 0,
on_error, on_error, false, cb, opaque, &local_err,
&commit_active_job_driver, false, base);
if (local_err) {
error_propagate(errp, local_err);
goto error_restore_flags;
}
return;
error_restore_flags:
/* ignore error and errp for bdrv_reopen, because we want to propagate
* the original error */
bdrv_reopen(base, orig_base_flags, NULL);
return;
}
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