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86c6a3b690
xemu/block/replication.c
Vladimir Sementsov-Ogievskiy 86c6a3b690 qapi: backup: add perf.use-copy-range parameter 
Experiments show, that copy_range is not always making things faster.
So, to make experimentation simpler, let's add a parameter. Some more
perf parameters will be added soon, so here is a new struct.

For now, add new backup qmp parameter with x- prefix for the following
reasons:

 - We are going to add more performance parameters, some will be
   related to the whole block-copy process, some only to background
   copying in backup (ignored for copy-before-write operations).
 - On the other hand, we are going to use block-copy interface in other
   block jobs, which will need performance options as well.. And it
   should be the same structure or at least somehow related.

So, there are too much unclean things about how the interface and now
we need the new options mostly for testing. Let's keep them
experimental for a while.

In do_backup_common() new x-perf parameter handled in a way to
make further options addition simpler.

We add use-copy-range with default=true, and we'll change the default
in further patch, after moving backup to use block-copy.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20210116214705.822267-2-vsementsov@virtuozzo.com>
[mreitz: s/5\.2/6.0/]
Signed-off-by: Max Reitz <mreitz@redhat.com>
2021-01-26 14:36:37 +01:00

751 lines
22 KiB
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/*
* Replication Block filter
*
* Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
* Copyright (c) 2016 Intel Corporation
* Copyright (c) 2016 FUJITSU LIMITED
*
* Author:
* Wen Congyang <wency@cn.fujitsu.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 "qemu/module.h"
#include "qemu/option.h"
#include "block/nbd.h"
#include "block/blockjob.h"
#include "block/block_int.h"
#include "block/block_backup.h"
#include "sysemu/block-backend.h"
#include "qapi/error.h"
#include "qapi/qmp/qdict.h"
#include "replication.h"
typedef enum {
BLOCK_REPLICATION_NONE, /* block replication is not started */
BLOCK_REPLICATION_RUNNING, /* block replication is running */
BLOCK_REPLICATION_FAILOVER, /* failover is running in background */
BLOCK_REPLICATION_FAILOVER_FAILED, /* failover failed */
BLOCK_REPLICATION_DONE, /* block replication is done */
} ReplicationStage;
typedef struct BDRVReplicationState {
ReplicationMode mode;
ReplicationStage stage;
BdrvChild *active_disk;
BlockJob *commit_job;
BdrvChild *hidden_disk;
BdrvChild *secondary_disk;
BlockJob *backup_job;
char *top_id;
ReplicationState *rs;
Error *blocker;
bool orig_hidden_read_only;
bool orig_secondary_read_only;
int error;
} BDRVReplicationState;
static void replication_start(ReplicationState *rs, ReplicationMode mode,
Error **errp);
static void replication_do_checkpoint(ReplicationState *rs, Error **errp);
static void replication_get_error(ReplicationState *rs, Error **errp);
static void replication_stop(ReplicationState *rs, bool failover,
Error **errp);
#define REPLICATION_MODE "mode"
#define REPLICATION_TOP_ID "top-id"
static QemuOptsList replication_runtime_opts = {
.name = "replication",
.head = QTAILQ_HEAD_INITIALIZER(replication_runtime_opts.head),
.desc = {
{
.name = REPLICATION_MODE,
.type = QEMU_OPT_STRING,
},
{
.name = REPLICATION_TOP_ID,
.type = QEMU_OPT_STRING,
},
{ /* end of list */ }
},
};
static ReplicationOps replication_ops = {
.start = replication_start,
.checkpoint = replication_do_checkpoint,
.get_error = replication_get_error,
.stop = replication_stop,
};
static int replication_open(BlockDriverState *bs, QDict *options,
int flags, Error **errp)
{
int ret;
BDRVReplicationState *s = bs->opaque;
QemuOpts *opts = NULL;
const char *mode;
const char *top_id;
bs->file = bdrv_open_child(NULL, options, "file", bs, &child_of_bds,
BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
false, errp);
if (!bs->file) {
return -EINVAL;
}
ret = -EINVAL;
opts = qemu_opts_create(&replication_runtime_opts, NULL, 0, &error_abort);
if (!qemu_opts_absorb_qdict(opts, options, errp)) {
goto fail;
}
mode = qemu_opt_get(opts, REPLICATION_MODE);
if (!mode) {
error_setg(errp, "Missing the option mode");
goto fail;
}
if (!strcmp(mode, "primary")) {
s->mode = REPLICATION_MODE_PRIMARY;
top_id = qemu_opt_get(opts, REPLICATION_TOP_ID);
if (top_id) {
error_setg(errp,
"The primary side does not support option top-id");
goto fail;
}
} else if (!strcmp(mode, "secondary")) {
s->mode = REPLICATION_MODE_SECONDARY;
top_id = qemu_opt_get(opts, REPLICATION_TOP_ID);
s->top_id = g_strdup(top_id);
if (!s->top_id) {
error_setg(errp, "Missing the option top-id");
goto fail;
}
} else {
error_setg(errp,
"The option mode's value should be primary or secondary");
goto fail;
}
s->rs = replication_new(bs, &replication_ops);
ret = 0;
fail:
qemu_opts_del(opts);
return ret;
}
static void replication_close(BlockDriverState *bs)
{
BDRVReplicationState *s = bs->opaque;
Job *commit_job;
if (s->stage == BLOCK_REPLICATION_RUNNING) {
replication_stop(s->rs, false, NULL);
}
if (s->stage == BLOCK_REPLICATION_FAILOVER) {
commit_job = &s->commit_job->job;
assert(commit_job->aio_context == qemu_get_current_aio_context());
job_cancel_sync(commit_job);
}
if (s->mode == REPLICATION_MODE_SECONDARY) {
g_free(s->top_id);
}
replication_remove(s->rs);
}
static void replication_child_perm(BlockDriverState *bs, BdrvChild *c,
BdrvChildRole role,
BlockReopenQueue *reopen_queue,
uint64_t perm, uint64_t shared,
uint64_t *nperm, uint64_t *nshared)
{
*nperm = BLK_PERM_CONSISTENT_READ;
if ((bs->open_flags & (BDRV_O_INACTIVE | BDRV_O_RDWR)) == BDRV_O_RDWR) {
*nperm |= BLK_PERM_WRITE;
}
*nshared = BLK_PERM_CONSISTENT_READ
| BLK_PERM_WRITE
| BLK_PERM_WRITE_UNCHANGED;
return;
}
static int64_t replication_getlength(BlockDriverState *bs)
{
return bdrv_getlength(bs->file->bs);
}
static int replication_get_io_status(BDRVReplicationState *s)
{
switch (s->stage) {
case BLOCK_REPLICATION_NONE:
return -EIO;
case BLOCK_REPLICATION_RUNNING:
return 0;
case BLOCK_REPLICATION_FAILOVER:
return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 0;
case BLOCK_REPLICATION_FAILOVER_FAILED:
return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 1;
case BLOCK_REPLICATION_DONE:
/*
* active commit job completes, and active disk and secondary_disk
* is swapped, so we can operate bs->file directly
*/
return s->mode == REPLICATION_MODE_PRIMARY ? -EIO : 0;
default:
abort();
}
}
static int replication_return_value(BDRVReplicationState *s, int ret)
{
if (s->mode == REPLICATION_MODE_SECONDARY) {
return ret;
}
if (ret < 0) {
s->error = ret;
ret = 0;
}
return ret;
}
static coroutine_fn int replication_co_readv(BlockDriverState *bs,
int64_t sector_num,
int remaining_sectors,
QEMUIOVector *qiov)
{
BDRVReplicationState *s = bs->opaque;
int ret;
if (s->mode == REPLICATION_MODE_PRIMARY) {
/* We only use it to forward primary write requests */
return -EIO;
}
ret = replication_get_io_status(s);
if (ret < 0) {
return ret;
}
ret = bdrv_co_preadv(bs->file, sector_num * BDRV_SECTOR_SIZE,
remaining_sectors * BDRV_SECTOR_SIZE, qiov, 0);
return replication_return_value(s, ret);
}
static coroutine_fn int replication_co_writev(BlockDriverState *bs,
int64_t sector_num,
int remaining_sectors,
QEMUIOVector *qiov,
int flags)
{
BDRVReplicationState *s = bs->opaque;
QEMUIOVector hd_qiov;
uint64_t bytes_done = 0;
BdrvChild *top = bs->file;
BdrvChild *base = s->secondary_disk;
BdrvChild *target;
int ret;
int64_t n;
assert(!flags);
ret = replication_get_io_status(s);
if (ret < 0) {
goto out;
}
if (ret == 0) {
ret = bdrv_co_pwritev(top, sector_num * BDRV_SECTOR_SIZE,
remaining_sectors * BDRV_SECTOR_SIZE, qiov, 0);
return replication_return_value(s, ret);
}
/*
* Failover failed, only write to active disk if the sectors
* have already been allocated in active disk/hidden disk.
*/
qemu_iovec_init(&hd_qiov, qiov->niov);
while (remaining_sectors > 0) {
int64_t count;
ret = bdrv_is_allocated_above(top->bs, base->bs, false,
sector_num * BDRV_SECTOR_SIZE,
remaining_sectors * BDRV_SECTOR_SIZE,
&count);
if (ret < 0) {
goto out1;
}
assert(QEMU_IS_ALIGNED(count, BDRV_SECTOR_SIZE));
n = count >> BDRV_SECTOR_BITS;
qemu_iovec_reset(&hd_qiov);
qemu_iovec_concat(&hd_qiov, qiov, bytes_done, count);
target = ret ? top : base;
ret = bdrv_co_pwritev(target, sector_num * BDRV_SECTOR_SIZE,
n * BDRV_SECTOR_SIZE, &hd_qiov, 0);
if (ret < 0) {
goto out1;
}
remaining_sectors -= n;
sector_num += n;
bytes_done += count;
}
out1:
qemu_iovec_destroy(&hd_qiov);
out:
return ret;
}
static void secondary_do_checkpoint(BDRVReplicationState *s, Error **errp)
{
Error *local_err = NULL;
int ret;
if (!s->backup_job) {
error_setg(errp, "Backup job was cancelled unexpectedly");
return;
}
backup_do_checkpoint(s->backup_job, &local_err);
if (local_err) {
error_propagate(errp, local_err);
return;
}
if (!s->active_disk->bs->drv) {
error_setg(errp, "Active disk %s is ejected",
s->active_disk->bs->node_name);
return;
}
ret = bdrv_make_empty(s->active_disk, errp);
if (ret < 0) {
return;
}
if (!s->hidden_disk->bs->drv) {
error_setg(errp, "Hidden disk %s is ejected",
s->hidden_disk->bs->node_name);
return;
}
BlockBackend *blk = blk_new(qemu_get_current_aio_context(),
BLK_PERM_WRITE, BLK_PERM_ALL);
blk_insert_bs(blk, s->hidden_disk->bs, &local_err);
if (local_err) {
error_propagate(errp, local_err);
blk_unref(blk);
return;
}
ret = blk_make_empty(blk, errp);
blk_unref(blk);
if (ret < 0) {
return;
}
}
/* This function is supposed to be called twice:
* first with writable = true, then with writable = false.
* The first call puts s->hidden_disk and s->secondary_disk in
* r/w mode, and the second puts them back in their original state.
*/
static void reopen_backing_file(BlockDriverState *bs, bool writable,
Error **errp)
{
BDRVReplicationState *s = bs->opaque;
BlockReopenQueue *reopen_queue = NULL;
if (writable) {
s->orig_hidden_read_only = bdrv_is_read_only(s->hidden_disk->bs);
s->orig_secondary_read_only = bdrv_is_read_only(s->secondary_disk->bs);
}
bdrv_subtree_drained_begin(s->hidden_disk->bs);
bdrv_subtree_drained_begin(s->secondary_disk->bs);
if (s->orig_hidden_read_only) {
QDict *opts = qdict_new();
qdict_put_bool(opts, BDRV_OPT_READ_ONLY, !writable);
reopen_queue = bdrv_reopen_queue(reopen_queue, s->hidden_disk->bs,
opts, true);
}
if (s->orig_secondary_read_only) {
QDict *opts = qdict_new();
qdict_put_bool(opts, BDRV_OPT_READ_ONLY, !writable);
reopen_queue = bdrv_reopen_queue(reopen_queue, s->secondary_disk->bs,
opts, true);
}
if (reopen_queue) {
bdrv_reopen_multiple(reopen_queue, errp);
}
bdrv_subtree_drained_end(s->hidden_disk->bs);
bdrv_subtree_drained_end(s->secondary_disk->bs);
}
static void backup_job_cleanup(BlockDriverState *bs)
{
BDRVReplicationState *s = bs->opaque;
BlockDriverState *top_bs;
s->backup_job = NULL;
top_bs = bdrv_lookup_bs(s->top_id, s->top_id, NULL);
if (!top_bs) {
return;
}
bdrv_op_unblock_all(top_bs, s->blocker);
error_free(s->blocker);
reopen_backing_file(bs, false, NULL);
}
static void backup_job_completed(void *opaque, int ret)
{
BlockDriverState *bs = opaque;
BDRVReplicationState *s = bs->opaque;
if (s->stage != BLOCK_REPLICATION_FAILOVER) {
/* The backup job is cancelled unexpectedly */
s->error = -EIO;
}
backup_job_cleanup(bs);
}
static bool check_top_bs(BlockDriverState *top_bs, BlockDriverState *bs)
{
BdrvChild *child;
/* The bs itself is the top_bs */
if (top_bs == bs) {
return true;
}
/* Iterate over top_bs's children */
QLIST_FOREACH(child, &top_bs->children, next) {
if (child->bs == bs || check_top_bs(child->bs, bs)) {
return true;
}
}
return false;
}
static void replication_start(ReplicationState *rs, ReplicationMode mode,
Error **errp)
{
BlockDriverState *bs = rs->opaque;
BDRVReplicationState *s;
BlockDriverState *top_bs;
int64_t active_length, hidden_length, disk_length;
AioContext *aio_context;
Error *local_err = NULL;
BackupPerf perf = { .use_copy_range = true };
aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
s = bs->opaque;
if (s->stage == BLOCK_REPLICATION_DONE ||
s->stage == BLOCK_REPLICATION_FAILOVER) {
/*
* This case happens when a secondary is promoted to primary.
* Ignore the request because the secondary side of replication
* doesn't have to do anything anymore.
*/
aio_context_release(aio_context);
return;
}
if (s->stage != BLOCK_REPLICATION_NONE) {
error_setg(errp, "Block replication is running or done");
aio_context_release(aio_context);
return;
}
if (s->mode != mode) {
error_setg(errp, "The parameter mode's value is invalid, needs %d,"
" but got %d", s->mode, mode);
aio_context_release(aio_context);
return;
}
switch (s->mode) {
case REPLICATION_MODE_PRIMARY:
break;
case REPLICATION_MODE_SECONDARY:
s->active_disk = bs->file;
if (!s->active_disk || !s->active_disk->bs ||
!s->active_disk->bs->backing) {
error_setg(errp, "Active disk doesn't have backing file");
aio_context_release(aio_context);
return;
}
s->hidden_disk = s->active_disk->bs->backing;
if (!s->hidden_disk->bs || !s->hidden_disk->bs->backing) {
error_setg(errp, "Hidden disk doesn't have backing file");
aio_context_release(aio_context);
return;
}
s->secondary_disk = s->hidden_disk->bs->backing;
if (!s->secondary_disk->bs || !bdrv_has_blk(s->secondary_disk->bs)) {
error_setg(errp, "The secondary disk doesn't have block backend");
aio_context_release(aio_context);
return;
}
/* verify the length */
active_length = bdrv_getlength(s->active_disk->bs);
hidden_length = bdrv_getlength(s->hidden_disk->bs);
disk_length = bdrv_getlength(s->secondary_disk->bs);
if (active_length < 0 || hidden_length < 0 || disk_length < 0 ||
active_length != hidden_length || hidden_length != disk_length) {
error_setg(errp, "Active disk, hidden disk, secondary disk's length"
" are not the same");
aio_context_release(aio_context);
return;
}
/* Must be true, or the bdrv_getlength() calls would have failed */
assert(s->active_disk->bs->drv && s->hidden_disk->bs->drv);
if (!s->active_disk->bs->drv->bdrv_make_empty ||
!s->hidden_disk->bs->drv->bdrv_make_empty) {
error_setg(errp,
"Active disk or hidden disk doesn't support make_empty");
aio_context_release(aio_context);
return;
}
/* reopen the backing file in r/w mode */
reopen_backing_file(bs, true, &local_err);
if (local_err) {
error_propagate(errp, local_err);
aio_context_release(aio_context);
return;
}
/* start backup job now */
error_setg(&s->blocker,
"Block device is in use by internal backup job");
top_bs = bdrv_lookup_bs(s->top_id, s->top_id, NULL);
if (!top_bs || !bdrv_is_root_node(top_bs) ||
!check_top_bs(top_bs, bs)) {
error_setg(errp, "No top_bs or it is invalid");
reopen_backing_file(bs, false, NULL);
aio_context_release(aio_context);
return;
}
bdrv_op_block_all(top_bs, s->blocker);
bdrv_op_unblock(top_bs, BLOCK_OP_TYPE_DATAPLANE, s->blocker);
s->backup_job = backup_job_create(
NULL, s->secondary_disk->bs, s->hidden_disk->bs,
0, MIRROR_SYNC_MODE_NONE, NULL, 0, false, NULL,
&perf,
BLOCKDEV_ON_ERROR_REPORT,
BLOCKDEV_ON_ERROR_REPORT, JOB_INTERNAL,
backup_job_completed, bs, NULL, &local_err);
if (local_err) {
error_propagate(errp, local_err);
backup_job_cleanup(bs);
aio_context_release(aio_context);
return;
}
job_start(&s->backup_job->job);
break;
default:
aio_context_release(aio_context);
abort();
}
s->stage = BLOCK_REPLICATION_RUNNING;
if (s->mode == REPLICATION_MODE_SECONDARY) {
secondary_do_checkpoint(s, errp);
}
s->error = 0;
aio_context_release(aio_context);
}
static void replication_do_checkpoint(ReplicationState *rs, Error **errp)
{
BlockDriverState *bs = rs->opaque;
BDRVReplicationState *s;
AioContext *aio_context;
aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
s = bs->opaque;
if (s->stage == BLOCK_REPLICATION_DONE ||
s->stage == BLOCK_REPLICATION_FAILOVER) {
/*
* This case happens when a secondary was promoted to primary.
* Ignore the request because the secondary side of replication
* doesn't have to do anything anymore.
*/
aio_context_release(aio_context);
return;
}
if (s->mode == REPLICATION_MODE_SECONDARY) {
secondary_do_checkpoint(s, errp);
}
aio_context_release(aio_context);
}
static void replication_get_error(ReplicationState *rs, Error **errp)
{
BlockDriverState *bs = rs->opaque;
BDRVReplicationState *s;
AioContext *aio_context;
aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
s = bs->opaque;
if (s->stage == BLOCK_REPLICATION_NONE) {
error_setg(errp, "Block replication is not running");
aio_context_release(aio_context);
return;
}
if (s->error) {
error_setg(errp, "I/O error occurred");
aio_context_release(aio_context);
return;
}
aio_context_release(aio_context);
}
static void replication_done(void *opaque, int ret)
{
BlockDriverState *bs = opaque;
BDRVReplicationState *s = bs->opaque;
if (ret == 0) {
s->stage = BLOCK_REPLICATION_DONE;
s->active_disk = NULL;
s->secondary_disk = NULL;
s->hidden_disk = NULL;
s->error = 0;
} else {
s->stage = BLOCK_REPLICATION_FAILOVER_FAILED;
s->error = -EIO;
}
}
static void replication_stop(ReplicationState *rs, bool failover, Error **errp)
{
BlockDriverState *bs = rs->opaque;
BDRVReplicationState *s;
AioContext *aio_context;
aio_context = bdrv_get_aio_context(bs);
aio_context_acquire(aio_context);
s = bs->opaque;
if (s->stage == BLOCK_REPLICATION_DONE ||
s->stage == BLOCK_REPLICATION_FAILOVER) {
/*
* This case happens when a secondary was promoted to primary.
* Ignore the request because the secondary side of replication
* doesn't have to do anything anymore.
*/
aio_context_release(aio_context);
return;
}
if (s->stage != BLOCK_REPLICATION_RUNNING) {
error_setg(errp, "Block replication is not running");
aio_context_release(aio_context);
return;
}
switch (s->mode) {
case REPLICATION_MODE_PRIMARY:
s->stage = BLOCK_REPLICATION_DONE;
s->error = 0;
break;
case REPLICATION_MODE_SECONDARY:
/*
* This BDS will be closed, and the job should be completed
* before the BDS is closed, because we will access hidden
* disk, secondary disk in backup_job_completed().
*/
if (s->backup_job) {
job_cancel_sync(&s->backup_job->job);
}
if (!failover) {
secondary_do_checkpoint(s, errp);
s->stage = BLOCK_REPLICATION_DONE;
aio_context_release(aio_context);
return;
}
s->stage = BLOCK_REPLICATION_FAILOVER;
s->commit_job = commit_active_start(
NULL, s->active_disk->bs, s->secondary_disk->bs,
JOB_INTERNAL, 0, BLOCKDEV_ON_ERROR_REPORT,
NULL, replication_done, bs, true, errp);
break;
default:
aio_context_release(aio_context);
abort();
}
aio_context_release(aio_context);
}
static const char *const replication_strong_runtime_opts[] = {
REPLICATION_MODE,
REPLICATION_TOP_ID,
NULL
};
static BlockDriver bdrv_replication = {
.format_name = "replication",
.instance_size = sizeof(BDRVReplicationState),
.bdrv_open = replication_open,
.bdrv_close = replication_close,
.bdrv_child_perm = replication_child_perm,
.bdrv_getlength = replication_getlength,
.bdrv_co_readv = replication_co_readv,
.bdrv_co_writev = replication_co_writev,
.is_filter = true,
.has_variable_length = true,
.strong_runtime_opts = replication_strong_runtime_opts,
};
static void bdrv_replication_init(void)
{
bdrv_register(&bdrv_replication);
}
block_init(bdrv_replication_init);
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