No reason to limit buffered copy to one cluster. Let's allow up to 1 MiB. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: 20191022111805.3432-7-vsementsov@virtuozzo.com Signed-off-by: Max Reitz <mreitz@redhat.com>
352 lines
10 KiB
C
352 lines
10 KiB
C
/*
|
|
* block_copy API
|
|
*
|
|
* Copyright (C) 2013 Proxmox Server Solutions
|
|
* Copyright (c) 2019 Virtuozzo International GmbH.
|
|
*
|
|
* Authors:
|
|
* Dietmar Maurer (dietmar@proxmox.com)
|
|
* Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.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 "qapi/error.h"
|
|
#include "block/block-copy.h"
|
|
#include "sysemu/block-backend.h"
|
|
#include "qemu/units.h"
|
|
|
|
#define BLOCK_COPY_MAX_COPY_RANGE (16 * MiB)
|
|
#define BLOCK_COPY_MAX_BUFFER (1 * MiB)
|
|
#define BLOCK_COPY_MAX_MEM (128 * MiB)
|
|
|
|
static void coroutine_fn block_copy_wait_inflight_reqs(BlockCopyState *s,
|
|
int64_t start,
|
|
int64_t end)
|
|
{
|
|
BlockCopyInFlightReq *req;
|
|
bool waited;
|
|
|
|
do {
|
|
waited = false;
|
|
QLIST_FOREACH(req, &s->inflight_reqs, list) {
|
|
if (end > req->start_byte && start < req->end_byte) {
|
|
qemu_co_queue_wait(&req->wait_queue, NULL);
|
|
waited = true;
|
|
break;
|
|
}
|
|
}
|
|
} while (waited);
|
|
}
|
|
|
|
static void block_copy_inflight_req_begin(BlockCopyState *s,
|
|
BlockCopyInFlightReq *req,
|
|
int64_t start, int64_t end)
|
|
{
|
|
req->start_byte = start;
|
|
req->end_byte = end;
|
|
qemu_co_queue_init(&req->wait_queue);
|
|
QLIST_INSERT_HEAD(&s->inflight_reqs, req, list);
|
|
}
|
|
|
|
static void coroutine_fn block_copy_inflight_req_end(BlockCopyInFlightReq *req)
|
|
{
|
|
QLIST_REMOVE(req, list);
|
|
qemu_co_queue_restart_all(&req->wait_queue);
|
|
}
|
|
|
|
void block_copy_state_free(BlockCopyState *s)
|
|
{
|
|
if (!s) {
|
|
return;
|
|
}
|
|
|
|
bdrv_release_dirty_bitmap(s->copy_bitmap);
|
|
shres_destroy(s->mem);
|
|
g_free(s);
|
|
}
|
|
|
|
BlockCopyState *block_copy_state_new(BdrvChild *source, BdrvChild *target,
|
|
int64_t cluster_size,
|
|
BdrvRequestFlags write_flags, Error **errp)
|
|
{
|
|
BlockCopyState *s;
|
|
BdrvDirtyBitmap *copy_bitmap;
|
|
uint32_t max_transfer =
|
|
MIN_NON_ZERO(INT_MAX,
|
|
MIN_NON_ZERO(source->bs->bl.max_transfer,
|
|
target->bs->bl.max_transfer));
|
|
|
|
copy_bitmap = bdrv_create_dirty_bitmap(source->bs, cluster_size, NULL,
|
|
errp);
|
|
if (!copy_bitmap) {
|
|
return NULL;
|
|
}
|
|
bdrv_disable_dirty_bitmap(copy_bitmap);
|
|
|
|
s = g_new(BlockCopyState, 1);
|
|
*s = (BlockCopyState) {
|
|
.source = source,
|
|
.target = target,
|
|
.copy_bitmap = copy_bitmap,
|
|
.cluster_size = cluster_size,
|
|
.len = bdrv_dirty_bitmap_size(copy_bitmap),
|
|
.write_flags = write_flags,
|
|
.mem = shres_create(BLOCK_COPY_MAX_MEM),
|
|
};
|
|
|
|
if (max_transfer < cluster_size) {
|
|
/*
|
|
* copy_range does not respect max_transfer. We don't want to bother
|
|
* with requests smaller than block-copy cluster size, so fallback to
|
|
* buffered copying (read and write respect max_transfer on their
|
|
* behalf).
|
|
*/
|
|
s->use_copy_range = false;
|
|
s->copy_size = cluster_size;
|
|
} else if (write_flags & BDRV_REQ_WRITE_COMPRESSED) {
|
|
/* Compression is not supported for copy_range */
|
|
s->use_copy_range = false;
|
|
s->copy_size = MAX(cluster_size, BLOCK_COPY_MAX_BUFFER);
|
|
} else {
|
|
/*
|
|
* copy_range does not respect max_transfer (it's a TODO), so we factor
|
|
* that in here.
|
|
*/
|
|
s->use_copy_range = true;
|
|
s->copy_size = MIN(MAX(cluster_size, BLOCK_COPY_MAX_COPY_RANGE),
|
|
QEMU_ALIGN_DOWN(max_transfer, cluster_size));
|
|
}
|
|
|
|
QLIST_INIT(&s->inflight_reqs);
|
|
|
|
return s;
|
|
}
|
|
|
|
void block_copy_set_callbacks(
|
|
BlockCopyState *s,
|
|
ProgressBytesCallbackFunc progress_bytes_callback,
|
|
ProgressResetCallbackFunc progress_reset_callback,
|
|
void *progress_opaque)
|
|
{
|
|
s->progress_bytes_callback = progress_bytes_callback;
|
|
s->progress_reset_callback = progress_reset_callback;
|
|
s->progress_opaque = progress_opaque;
|
|
}
|
|
|
|
/*
|
|
* block_copy_do_copy
|
|
*
|
|
* Do copy of cluser-aligned chunk. @end is allowed to exceed s->len only to
|
|
* cover last cluster when s->len is not aligned to clusters.
|
|
*
|
|
* No sync here: nor bitmap neighter intersecting requests handling, only copy.
|
|
*
|
|
* Returns 0 on success.
|
|
*/
|
|
static int coroutine_fn block_copy_do_copy(BlockCopyState *s,
|
|
int64_t start, int64_t end,
|
|
bool *error_is_read)
|
|
{
|
|
int ret;
|
|
int nbytes = MIN(end, s->len) - start;
|
|
void *bounce_buffer = NULL;
|
|
|
|
assert(QEMU_IS_ALIGNED(start, s->cluster_size));
|
|
assert(QEMU_IS_ALIGNED(end, s->cluster_size));
|
|
assert(end < s->len || end == QEMU_ALIGN_UP(s->len, s->cluster_size));
|
|
|
|
if (s->use_copy_range) {
|
|
ret = bdrv_co_copy_range(s->source, start, s->target, start, nbytes,
|
|
0, s->write_flags);
|
|
if (ret < 0) {
|
|
trace_block_copy_copy_range_fail(s, start, ret);
|
|
s->use_copy_range = false;
|
|
s->copy_size = MAX(s->cluster_size, BLOCK_COPY_MAX_BUFFER);
|
|
/* Fallback to read+write with allocated buffer */
|
|
} else {
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* In case of failed copy_range request above, we may proceed with buffered
|
|
* request larger than BLOCK_COPY_MAX_BUFFER. Still, further requests will
|
|
* be properly limited, so don't care too much.
|
|
*/
|
|
|
|
bounce_buffer = qemu_blockalign(s->source->bs, nbytes);
|
|
|
|
ret = bdrv_co_pread(s->source, start, nbytes, bounce_buffer, 0);
|
|
if (ret < 0) {
|
|
trace_block_copy_read_fail(s, start, ret);
|
|
if (error_is_read) {
|
|
*error_is_read = true;
|
|
}
|
|
goto out;
|
|
}
|
|
|
|
ret = bdrv_co_pwrite(s->target, start, nbytes, bounce_buffer,
|
|
s->write_flags);
|
|
if (ret < 0) {
|
|
trace_block_copy_write_fail(s, start, ret);
|
|
if (error_is_read) {
|
|
*error_is_read = false;
|
|
}
|
|
goto out;
|
|
}
|
|
|
|
out:
|
|
qemu_vfree(bounce_buffer);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Check if the cluster starting at offset is allocated or not.
|
|
* return via pnum the number of contiguous clusters sharing this allocation.
|
|
*/
|
|
static int block_copy_is_cluster_allocated(BlockCopyState *s, int64_t offset,
|
|
int64_t *pnum)
|
|
{
|
|
BlockDriverState *bs = s->source->bs;
|
|
int64_t count, total_count = 0;
|
|
int64_t bytes = s->len - offset;
|
|
int ret;
|
|
|
|
assert(QEMU_IS_ALIGNED(offset, s->cluster_size));
|
|
|
|
while (true) {
|
|
ret = bdrv_is_allocated(bs, offset, bytes, &count);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
total_count += count;
|
|
|
|
if (ret || count == 0) {
|
|
/*
|
|
* ret: partial segment(s) are considered allocated.
|
|
* otherwise: unallocated tail is treated as an entire segment.
|
|
*/
|
|
*pnum = DIV_ROUND_UP(total_count, s->cluster_size);
|
|
return ret;
|
|
}
|
|
|
|
/* Unallocated segment(s) with uncertain following segment(s) */
|
|
if (total_count >= s->cluster_size) {
|
|
*pnum = total_count / s->cluster_size;
|
|
return 0;
|
|
}
|
|
|
|
offset += count;
|
|
bytes -= count;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Reset bits in copy_bitmap starting at offset if they represent unallocated
|
|
* data in the image. May reset subsequent contiguous bits.
|
|
* @return 0 when the cluster at @offset was unallocated,
|
|
* 1 otherwise, and -ret on error.
|
|
*/
|
|
int64_t block_copy_reset_unallocated(BlockCopyState *s,
|
|
int64_t offset, int64_t *count)
|
|
{
|
|
int ret;
|
|
int64_t clusters, bytes;
|
|
|
|
ret = block_copy_is_cluster_allocated(s, offset, &clusters);
|
|
if (ret < 0) {
|
|
return ret;
|
|
}
|
|
|
|
bytes = clusters * s->cluster_size;
|
|
|
|
if (!ret) {
|
|
bdrv_reset_dirty_bitmap(s->copy_bitmap, offset, bytes);
|
|
s->progress_reset_callback(s->progress_opaque);
|
|
}
|
|
|
|
*count = bytes;
|
|
return ret;
|
|
}
|
|
|
|
int coroutine_fn block_copy(BlockCopyState *s,
|
|
int64_t start, uint64_t bytes,
|
|
bool *error_is_read)
|
|
{
|
|
int ret = 0;
|
|
int64_t end = bytes + start; /* bytes */
|
|
int64_t status_bytes;
|
|
BlockCopyInFlightReq req;
|
|
|
|
/*
|
|
* block_copy() user is responsible for keeping source and target in same
|
|
* aio context
|
|
*/
|
|
assert(bdrv_get_aio_context(s->source->bs) ==
|
|
bdrv_get_aio_context(s->target->bs));
|
|
|
|
assert(QEMU_IS_ALIGNED(start, s->cluster_size));
|
|
assert(QEMU_IS_ALIGNED(end, s->cluster_size));
|
|
|
|
block_copy_wait_inflight_reqs(s, start, bytes);
|
|
block_copy_inflight_req_begin(s, &req, start, end);
|
|
|
|
while (start < end) {
|
|
int64_t next_zero, chunk_end;
|
|
|
|
if (!bdrv_dirty_bitmap_get(s->copy_bitmap, start)) {
|
|
trace_block_copy_skip(s, start);
|
|
start += s->cluster_size;
|
|
continue; /* already copied */
|
|
}
|
|
|
|
chunk_end = MIN(end, start + s->copy_size);
|
|
|
|
next_zero = bdrv_dirty_bitmap_next_zero(s->copy_bitmap, start,
|
|
chunk_end - start);
|
|
if (next_zero >= 0) {
|
|
assert(next_zero > start); /* start is dirty */
|
|
assert(next_zero < chunk_end); /* no need to do MIN() */
|
|
chunk_end = next_zero;
|
|
}
|
|
|
|
if (s->skip_unallocated) {
|
|
ret = block_copy_reset_unallocated(s, start, &status_bytes);
|
|
if (ret == 0) {
|
|
trace_block_copy_skip_range(s, start, status_bytes);
|
|
start += status_bytes;
|
|
continue;
|
|
}
|
|
/* Clamp to known allocated region */
|
|
chunk_end = MIN(chunk_end, start + status_bytes);
|
|
}
|
|
|
|
trace_block_copy_process(s, start);
|
|
|
|
bdrv_reset_dirty_bitmap(s->copy_bitmap, start, chunk_end - start);
|
|
|
|
co_get_from_shres(s->mem, chunk_end - start);
|
|
ret = block_copy_do_copy(s, start, chunk_end, error_is_read);
|
|
co_put_to_shres(s->mem, chunk_end - start);
|
|
if (ret < 0) {
|
|
bdrv_set_dirty_bitmap(s->copy_bitmap, start, chunk_end - start);
|
|
break;
|
|
}
|
|
|
|
s->progress_bytes_callback(chunk_end - start, s->progress_opaque);
|
|
start = chunk_end;
|
|
ret = 0;
|
|
}
|
|
|
|
block_copy_inflight_req_end(&req);
|
|
|
|
return ret;
|
|
}
|