backup: move to block-copy
This brings async request handling and block-status driven chunk sizes to backup out of the box, which improves backup performance. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-Id: <20210116214705.822267-18-vsementsov@virtuozzo.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy
Max Reitz
parent
511e7d31bf
commit
71eed4cebe
187
block/backup.c
187
block/backup.c
@ -22,7 +22,6 @@
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#include "block/block-copy.h"
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#include "qapi/error.h"
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#include "qapi/qmp/qerror.h"
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#include "qemu/ratelimit.h"
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#include "qemu/cutils.h"
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#include "sysemu/block-backend.h"
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#include "qemu/bitmap.h"
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@ -44,41 +43,17 @@ typedef struct BackupBlockJob {
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BlockdevOnError on_source_error;
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BlockdevOnError on_target_error;
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uint64_t len;
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uint64_t bytes_read;
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int64_t cluster_size;
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BackupPerf perf;
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BlockCopyState *bcs;
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bool wait;
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BlockCopyCallState *bg_bcs_call;
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} BackupBlockJob;
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static const BlockJobDriver backup_job_driver;
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static void backup_progress_bytes_callback(int64_t bytes, void *opaque)
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{
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BackupBlockJob *s = opaque;
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s->bytes_read += bytes;
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}
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static int coroutine_fn backup_do_cow(BackupBlockJob *job,
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int64_t offset, uint64_t bytes,
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bool *error_is_read)
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{
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int ret = 0;
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int64_t start, end; /* bytes */
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start = QEMU_ALIGN_DOWN(offset, job->cluster_size);
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end = QEMU_ALIGN_UP(bytes + offset, job->cluster_size);
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trace_backup_do_cow_enter(job, start, offset, bytes);
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ret = block_copy(job->bcs, start, end - start, true, error_is_read);
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trace_backup_do_cow_return(job, offset, bytes, ret);
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return ret;
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}
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static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
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{
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BdrvDirtyBitmap *bm;
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@ -158,53 +133,96 @@ static BlockErrorAction backup_error_action(BackupBlockJob *job,
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}
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}
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static bool coroutine_fn yield_and_check(BackupBlockJob *job)
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static void coroutine_fn backup_block_copy_callback(void *opaque)
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{
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uint64_t delay_ns;
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BackupBlockJob *s = opaque;
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if (job_is_cancelled(&job->common.job)) {
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return true;
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if (s->wait) {
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s->wait = false;
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aio_co_wake(s->common.job.co);
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} else {
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job_enter(&s->common.job);
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}
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/*
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* We need to yield even for delay_ns = 0 so that bdrv_drain_all() can
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* return. Without a yield, the VM would not reboot.
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*/
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delay_ns = block_job_ratelimit_get_delay(&job->common, job->bytes_read);
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job->bytes_read = 0;
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job_sleep_ns(&job->common.job, delay_ns);
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if (job_is_cancelled(&job->common.job)) {
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return true;
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}
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return false;
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}
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static int coroutine_fn backup_loop(BackupBlockJob *job)
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{
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bool error_is_read;
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int64_t offset;
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BdrvDirtyBitmapIter *bdbi;
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BlockCopyCallState *s = NULL;
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int ret = 0;
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bool error_is_read;
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BlockErrorAction act;
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bdbi = bdrv_dirty_iter_new(block_copy_dirty_bitmap(job->bcs));
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while ((offset = bdrv_dirty_iter_next(bdbi)) != -1) {
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do {
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if (yield_and_check(job)) {
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goto out;
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}
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ret = backup_do_cow(job, offset, job->cluster_size, &error_is_read);
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if (ret < 0 && backup_error_action(job, error_is_read, -ret) ==
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BLOCK_ERROR_ACTION_REPORT)
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{
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goto out;
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}
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} while (ret < 0);
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while (true) { /* retry loop */
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job->bg_bcs_call = s = block_copy_async(job->bcs, 0,
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QEMU_ALIGN_UP(job->len, job->cluster_size),
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job->perf.max_workers, job->perf.max_chunk,
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backup_block_copy_callback, job);
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while (!block_copy_call_finished(s) &&
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!job_is_cancelled(&job->common.job))
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{
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job_yield(&job->common.job);
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}
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if (!block_copy_call_finished(s)) {
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assert(job_is_cancelled(&job->common.job));
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/*
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* Note that we can't use job_yield() here, as it doesn't work for
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* cancelled job.
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*/
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block_copy_call_cancel(s);
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job->wait = true;
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qemu_coroutine_yield();
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assert(block_copy_call_finished(s));
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ret = 0;
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goto out;
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}
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if (job_is_cancelled(&job->common.job) ||
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block_copy_call_succeeded(s))
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{
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ret = 0;
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goto out;
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}
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if (block_copy_call_cancelled(s)) {
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/*
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* Job is not cancelled but only block-copy call. This is possible
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* after job pause. Now the pause is finished, start new block-copy
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* iteration.
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*/
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block_copy_call_free(s);
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continue;
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}
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/* The only remaining case is failed block-copy call. */
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assert(block_copy_call_failed(s));
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ret = block_copy_call_status(s, &error_is_read);
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act = backup_error_action(job, error_is_read, -ret);
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switch (act) {
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case BLOCK_ERROR_ACTION_REPORT:
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goto out;
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case BLOCK_ERROR_ACTION_STOP:
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/*
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* Go to pause prior to starting new block-copy call on the next
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* iteration.
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*/
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job_pause_point(&job->common.job);
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break;
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case BLOCK_ERROR_ACTION_IGNORE:
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/* Proceed to new block-copy call to retry. */
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break;
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default:
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abort();
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}
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block_copy_call_free(s);
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}
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out:
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bdrv_dirty_iter_free(bdbi);
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out:
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block_copy_call_free(s);
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job->bg_bcs_call = NULL;
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return ret;
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}
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@ -245,7 +263,13 @@ static int coroutine_fn backup_run(Job *job, Error **errp)
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int64_t count;
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for (offset = 0; offset < s->len; ) {
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if (yield_and_check(s)) {
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if (job_is_cancelled(job)) {
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return -ECANCELED;
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}
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job_pause_point(job);
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if (job_is_cancelled(job)) {
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return -ECANCELED;
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}
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@ -278,6 +302,33 @@ static int coroutine_fn backup_run(Job *job, Error **errp)
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return 0;
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}
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static void coroutine_fn backup_pause(Job *job)
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{
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BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
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if (s->bg_bcs_call && !block_copy_call_finished(s->bg_bcs_call)) {
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block_copy_call_cancel(s->bg_bcs_call);
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s->wait = true;
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qemu_coroutine_yield();
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}
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}
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static void coroutine_fn backup_set_speed(BlockJob *job, int64_t speed)
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{
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BackupBlockJob *s = container_of(job, BackupBlockJob, common);
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/*
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* block_job_set_speed() is called first from block_job_create(), when we
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* don't yet have s->bcs.
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*/
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if (s->bcs) {
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block_copy_set_speed(s->bcs, speed);
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if (s->bg_bcs_call) {
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block_copy_kick(s->bg_bcs_call);
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}
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}
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}
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static const BlockJobDriver backup_job_driver = {
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.job_driver = {
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.instance_size = sizeof(BackupBlockJob),
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@ -288,7 +339,9 @@ static const BlockJobDriver backup_job_driver = {
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.commit = backup_commit,
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.abort = backup_abort,
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.clean = backup_clean,
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}
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.pause = backup_pause,
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},
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.set_speed = backup_set_speed,
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};
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static int64_t backup_calculate_cluster_size(BlockDriverState *target,
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@ -485,8 +538,8 @@ BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
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job->len = len;
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job->perf = *perf;
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block_copy_set_progress_callback(bcs, backup_progress_bytes_callback, job);
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block_copy_set_progress_meter(bcs, &job->common.job.progress);
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block_copy_set_speed(bcs, speed);
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/* Required permissions are already taken by backup-top target */
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block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL,
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