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qemu-e2k/block/backup.c

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/*
* QEMU backup
*
* Copyright (C) 2013 Proxmox Server Solutions
* Copyright (c) 2019 Virtuozzo International GmbH.
*
* Authors:
* Dietmar Maurer (dietmar@proxmox.com)
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "trace.h"
#include "block/block.h"
#include "block/block_int.h"
#include "block/blockjob_int.h"
#include "block/block_backup.h"
#include "block/block-copy.h"
#include "qapi/error.h"
#include "qapi/qmp/qerror.h"
#include "qemu/cutils.h"
#include "sysemu/block-backend.h"
#include "qemu/bitmap.h"
#include "qemu/error-report.h"
#include "block/copy-before-write.h"
typedef struct BackupBlockJob {
BlockJob common;
BlockDriverState *cbw;
BlockDriverState *source_bs;
BlockDriverState *target_bs;
BdrvDirtyBitmap *sync_bitmap;
MirrorSyncMode sync_mode;
BitmapSyncMode bitmap_mode;
BlockdevOnError on_source_error;
BlockdevOnError on_target_error;
uint64_t len;
int64_t cluster_size;
BackupPerf perf;
BlockCopyState *bcs;
bool wait;
BlockCopyCallState *bg_bcs_call;
} BackupBlockJob;
static const BlockJobDriver backup_job_driver;
static void backup_cleanup_sync_bitmap(BackupBlockJob *job, int ret)
{
BdrvDirtyBitmap *bm;
bool sync = (((ret == 0) || (job->bitmap_mode == BITMAP_SYNC_MODE_ALWAYS)) \
&& (job->bitmap_mode != BITMAP_SYNC_MODE_NEVER));
if (sync) {
/*
* We succeeded, or we always intended to sync the bitmap.
* Delete this bitmap and install the child.
*/
bm = bdrv_dirty_bitmap_abdicate(job->sync_bitmap, NULL);
} else {
/*
* We failed, or we never intended to sync the bitmap anyway.
* Merge the successor back into the parent, keeping all data.
*/
bm = bdrv_reclaim_dirty_bitmap(job->sync_bitmap, NULL);
}
assert(bm);
if (ret < 0 && job->bitmap_mode == BITMAP_SYNC_MODE_ALWAYS) {
/* If we failed and synced, merge in the bits we didn't copy: */
bdrv_dirty_bitmap_merge_internal(bm, block_copy_dirty_bitmap(job->bcs),
NULL, true);
}
}
static void backup_commit(Job *job)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
if (s->sync_bitmap) {
backup_cleanup_sync_bitmap(s, 0);
}
}
static void backup_abort(Job *job)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
if (s->sync_bitmap) {
backup_cleanup_sync_bitmap(s, -1);
}
}
static void backup_clean(Job *job)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
block_job_remove_all_bdrv(&s->common);
bdrv_cbw_drop(s->cbw);
}
void backup_do_checkpoint(BlockJob *job, Error **errp)
{
BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common);
assert(block_job_driver(job) == &backup_job_driver);
if (backup_job->sync_mode != MIRROR_SYNC_MODE_NONE) {
error_setg(errp, "The backup job only supports block checkpoint in"
" sync=none mode");
return;
}
bdrv_set_dirty_bitmap(block_copy_dirty_bitmap(backup_job->bcs), 0,
backup_job->len);
}
static BlockErrorAction backup_error_action(BackupBlockJob *job,
bool read, int error)
{
if (read) {
return block_job_error_action(&job->common, job->on_source_error,
true, error);
} else {
return block_job_error_action(&job->common, job->on_target_error,
false, error);
}
}
static void coroutine_fn backup_block_copy_callback(void *opaque)
{
BackupBlockJob *s = opaque;
if (s->wait) {
s->wait = false;
aio_co_wake(s->common.job.co);
} else {
job_enter(&s->common.job);
}
}
static int coroutine_fn backup_loop(BackupBlockJob *job)
{
BlockCopyCallState *s = NULL;
int ret = 0;
bool error_is_read;
BlockErrorAction act;
while (true) { /* retry loop */
job->bg_bcs_call = s = block_copy_async(job->bcs, 0,
QEMU_ALIGN_UP(job->len, job->cluster_size),
job->perf.max_workers, job->perf.max_chunk,
backup_block_copy_callback, job);
while (!block_copy_call_finished(s) &&
!job_is_cancelled(&job->common.job))
{
job_yield(&job->common.job);
}
if (!block_copy_call_finished(s)) {
assert(job_is_cancelled(&job->common.job));
/*
* Note that we can't use job_yield() here, as it doesn't work for
* cancelled job.
*/
block_copy_call_cancel(s);
job->wait = true;
qemu_coroutine_yield();
assert(block_copy_call_finished(s));
ret = 0;
goto out;
}
if (job_is_cancelled(&job->common.job) ||
block_copy_call_succeeded(s))
{
ret = 0;
goto out;
}
if (block_copy_call_cancelled(s)) {
/*
* Job is not cancelled but only block-copy call. This is possible
* after job pause. Now the pause is finished, start new block-copy
* iteration.
*/
block_copy_call_free(s);
continue;
}
/* The only remaining case is failed block-copy call. */
assert(block_copy_call_failed(s));
ret = block_copy_call_status(s, &error_is_read);
act = backup_error_action(job, error_is_read, -ret);
switch (act) {
case BLOCK_ERROR_ACTION_REPORT:
goto out;
case BLOCK_ERROR_ACTION_STOP:
/*
* Go to pause prior to starting new block-copy call on the next
* iteration.
*/
job_pause_point(&job->common.job);
break;
case BLOCK_ERROR_ACTION_IGNORE:
/* Proceed to new block-copy call to retry. */
break;
default:
abort();
}
block_copy_call_free(s);
}
out:
block_copy_call_free(s);
job->bg_bcs_call = NULL;
return ret;
}
static void backup_init_bcs_bitmap(BackupBlockJob *job)
{
bool ret;
uint64_t estimate;
BdrvDirtyBitmap *bcs_bitmap = block_copy_dirty_bitmap(job->bcs);
if (job->sync_mode == MIRROR_SYNC_MODE_BITMAP) {
bdrv_clear_dirty_bitmap(bcs_bitmap, NULL);
ret = bdrv_dirty_bitmap_merge_internal(bcs_bitmap, job->sync_bitmap,
NULL, true);
assert(ret);
} else if (job->sync_mode == MIRROR_SYNC_MODE_TOP) {
/*
* We can't hog the coroutine to initialize this thoroughly.
* Set a flag and resume work when we are able to yield safely.
*/
block_copy_set_skip_unallocated(job->bcs, true);
}
estimate = bdrv_get_dirty_count(bcs_bitmap);
job_progress_set_remaining(&job->common.job, estimate);
}
static int coroutine_fn backup_run(Job *job, Error **errp)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
int ret;
backup_init_bcs_bitmap(s);
if (s->sync_mode == MIRROR_SYNC_MODE_TOP) {
int64_t offset = 0;
int64_t count;
for (offset = 0; offset < s->len; ) {
if (job_is_cancelled(job)) {
return -ECANCELED;
}
job_pause_point(job);
if (job_is_cancelled(job)) {
return -ECANCELED;
}
ret = block_copy_reset_unallocated(s->bcs, offset, &count);
if (ret < 0) {
return ret;
}
offset += count;
}
block_copy_set_skip_unallocated(s->bcs, false);
}
if (s->sync_mode == MIRROR_SYNC_MODE_NONE) {
/*
* All bits are set in bcs bitmap to allow any cluster to be copied.
* This does not actually require them to be copied.
*/
while (!job_is_cancelled(job)) {
/*
* Yield until the job is cancelled. We just let our before_write
* notify callback service CoW requests.
*/
job_yield(job);
}
} else {
return backup_loop(s);
}
return 0;
}
static void coroutine_fn backup_pause(Job *job)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
if (s->bg_bcs_call && !block_copy_call_finished(s->bg_bcs_call)) {
block_copy_call_cancel(s->bg_bcs_call);
s->wait = true;
qemu_coroutine_yield();
}
}
static void coroutine_fn backup_set_speed(BlockJob *job, int64_t speed)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common);
/*
* block_job_set_speed() is called first from block_job_create(), when we
* don't yet have s->bcs.
*/
if (s->bcs) {
block_copy_set_speed(s->bcs, speed);
if (s->bg_bcs_call) {
block_copy_kick(s->bg_bcs_call);
}
}
}
static bool backup_cancel(Job *job, bool force)
{
BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
bdrv_cancel_in_flight(s->target_bs);
return true;
}
static const BlockJobDriver backup_job_driver = {
.job_driver = {
.instance_size = sizeof(BackupBlockJob),
.job_type = JOB_TYPE_BACKUP,
.free = block_job_free,
.user_resume = block_job_user_resume,
.run = backup_run,
.commit = backup_commit,
.abort = backup_abort,
.clean = backup_clean,
.pause = backup_pause,
.cancel = backup_cancel,
},
.set_speed = backup_set_speed,
};
BlockJob *backup_job_create(const char *job_id, BlockDriverState *bs,
BlockDriverState *target, int64_t speed,
MirrorSyncMode sync_mode, BdrvDirtyBitmap *sync_bitmap,
BitmapSyncMode bitmap_mode,
bool compress,
const char *filter_node_name,
BackupPerf *perf,
BlockdevOnError on_source_error,
BlockdevOnError on_target_error,
int creation_flags,
BlockCompletionFunc *cb, void *opaque,
JobTxn *txn, Error **errp)
{
int64_t len, target_len;
BackupBlockJob *job = NULL;
int64_t cluster_size;
BlockDriverState *cbw = NULL;
BlockCopyState *bcs = NULL;
assert(bs);
assert(target);
GLOBAL_STATE_CODE();
/* QMP interface protects us from these cases */
assert(sync_mode != MIRROR_SYNC_MODE_INCREMENTAL);
assert(sync_bitmap || sync_mode != MIRROR_SYNC_MODE_BITMAP);
if (bs == target) {
error_setg(errp, "Source and target cannot be the same");
return NULL;
}
if (!bdrv_is_inserted(bs)) {
error_setg(errp, "Device is not inserted: %s",
bdrv_get_device_name(bs));
return NULL;
}
if (!bdrv_is_inserted(target)) {
error_setg(errp, "Device is not inserted: %s",
bdrv_get_device_name(target));
return NULL;
}
if (compress && !bdrv_supports_compressed_writes(target)) {
error_setg(errp, "Compression is not supported for this drive %s",
bdrv_get_device_name(target));
return NULL;
}
if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
return NULL;
}
if (bdrv_op_is_blocked(target, BLOCK_OP_TYPE_BACKUP_TARGET, errp)) {
return NULL;
}
if (perf->max_workers < 1 || perf->max_workers > INT_MAX) {
error_setg(errp, "max-workers must be between 1 and %d", INT_MAX);
return NULL;
}
if (perf->max_chunk < 0) {
error_setg(errp, "max-chunk must be zero (which means no limit) or "
"positive");
return NULL;
}
if (sync_bitmap) {
/* If we need to write to this bitmap, check that we can: */
if (bitmap_mode != BITMAP_SYNC_MODE_NEVER &&
bdrv_dirty_bitmap_check(sync_bitmap, BDRV_BITMAP_DEFAULT, errp)) {
return NULL;
}
/* Create a new bitmap, and freeze/disable this one. */
if (bdrv_dirty_bitmap_create_successor(sync_bitmap, errp) < 0) {
return NULL;
}
}
len = bdrv_getlength(bs);
if (len < 0) {
error_setg_errno(errp, -len, "Unable to get length for '%s'",
bdrv_get_device_or_node_name(bs));
goto error;
}
target_len = bdrv_getlength(target);
if (target_len < 0) {
error_setg_errno(errp, -target_len, "Unable to get length for '%s'",
bdrv_get_device_or_node_name(bs));
goto error;
}
if (target_len != len) {
error_setg(errp, "Source and target image have different sizes");
goto error;
}
cbw = bdrv_cbw_append(bs, target, filter_node_name, &bcs, errp);
if (!cbw) {
goto error;
}
cluster_size = block_copy_cluster_size(bcs);
if (perf->max_chunk && perf->max_chunk < cluster_size) {
error_setg(errp, "Required max-chunk (%" PRIi64 ") is less than backup "
"cluster size (%" PRIi64 ")", perf->max_chunk, cluster_size);
goto error;
}
/* job->len is fixed, so we can't allow resize */
job = block_job_create(job_id, &backup_job_driver, txn, cbw,
0, BLK_PERM_ALL,
speed, creation_flags, cb, opaque, errp);
if (!job) {
goto error;
}
job->cbw = cbw;
job->source_bs = bs;
job->target_bs = target;
job->on_source_error = on_source_error;
job->on_target_error = on_target_error;
job->sync_mode = sync_mode;
job->sync_bitmap = sync_bitmap;
job->bitmap_mode = bitmap_mode;
job->bcs = bcs;
job->cluster_size = cluster_size;
job->len = len;
job->perf = *perf;
block_copy_set_copy_opts(bcs, perf->use_copy_range, compress);
block_copy_set_progress_meter(bcs, &job->common.job.progress);
block_copy_set_speed(bcs, speed);
/* Required permissions are taken by copy-before-write filter target */
block_job_add_bdrv(&job->common, "target", target, 0, BLK_PERM_ALL,
&error_abort);
return &job->common;
error:
if (sync_bitmap) {
bdrv_reclaim_dirty_bitmap(sync_bitmap, NULL);
}
if (cbw) {
bdrv_cbw_drop(cbw);
}
return NULL;
}
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