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block/block-copy: refactor interfaces to use bytes instead of end
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We have a lot of "chunk_end - start" invocations, let's switch to
bytes/cur_bytes scheme instead.

While being here, improve check on block_copy_do_copy parameters to not
overflow when calculating nbytes and use int64_t for bytes in
block_copy for consistency.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200311103004.7649-7-vsementsov@virtuozzo.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
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@XanClic
Vladimir Sementsov-Ogievskiy authored and XanClic committed Mar 11, 2020
1 parent 17187cb commit dafaf13
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Showing 2 changed files with 44 additions and 40 deletions.
78 changes: 41 additions & 37 deletions block/block-copy.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -26,12 +26,12 @@

static BlockCopyInFlightReq *find_conflicting_inflight_req(BlockCopyState *s,
int64_t start,
int64_t end)
int64_t bytes)
{
BlockCopyInFlightReq *req;

QLIST_FOREACH(req, &s->inflight_reqs, list) {
if (end > req->start_byte && start < req->end_byte) {
if (start + bytes > req->start && start < req->start + req->bytes) {
return req;
}
}
Expand All @@ -41,21 +41,21 @@ static BlockCopyInFlightReq *find_conflicting_inflight_req(BlockCopyState *s,

static void coroutine_fn block_copy_wait_inflight_reqs(BlockCopyState *s,
int64_t start,
int64_t end)
int64_t bytes)
{
BlockCopyInFlightReq *req;

while ((req = find_conflicting_inflight_req(s, start, end))) {
while ((req = find_conflicting_inflight_req(s, start, bytes))) {
qemu_co_queue_wait(&req->wait_queue, NULL);
}
}

static void block_copy_inflight_req_begin(BlockCopyState *s,
BlockCopyInFlightReq *req,
int64_t start, int64_t end)
int64_t start, int64_t bytes)
{
req->start_byte = start;
req->end_byte = end;
req->start = start;
req->bytes = bytes;
qemu_co_queue_init(&req->wait_queue);
QLIST_INSERT_HEAD(&s->inflight_reqs, req, list);
}
Expand Down Expand Up @@ -153,24 +153,28 @@ void block_copy_set_progress_meter(BlockCopyState *s, ProgressMeter *pm)
/*
* 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.
* Do copy of cluster-aligned chunk. Requested region 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,
int64_t start, int64_t bytes,
bool zeroes, bool *error_is_read)
{
int ret;
int nbytes = MIN(end, s->len) - start;
int64_t nbytes = MIN(start + bytes, s->len) - start;
void *bounce_buffer = NULL;

assert(start >= 0 && bytes > 0 && INT64_MAX - start >= bytes);
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));
assert(QEMU_IS_ALIGNED(bytes, s->cluster_size));
assert(start < s->len);
assert(start + bytes <= s->len ||
start + bytes == QEMU_ALIGN_UP(s->len, s->cluster_size));
assert(nbytes < INT_MAX);

if (zeroes) {
ret = bdrv_co_pwrite_zeroes(s->target, start, nbytes, s->write_flags &
Expand Down Expand Up @@ -354,11 +358,10 @@ int64_t block_copy_reset_unallocated(BlockCopyState *s,
}

int coroutine_fn block_copy(BlockCopyState *s,
int64_t start, uint64_t bytes,
int64_t start, int64_t bytes,
bool *error_is_read)
{
int ret = 0;
int64_t end = bytes + start; /* bytes */
BlockCopyInFlightReq req;

/*
Expand All @@ -369,63 +372,64 @@ int coroutine_fn block_copy(BlockCopyState *s,
bdrv_get_aio_context(s->target->bs));

assert(QEMU_IS_ALIGNED(start, s->cluster_size));
assert(QEMU_IS_ALIGNED(end, s->cluster_size));
assert(QEMU_IS_ALIGNED(bytes, s->cluster_size));

block_copy_wait_inflight_reqs(s, start, bytes);
block_copy_inflight_req_begin(s, &req, start, end);
block_copy_inflight_req_begin(s, &req, start, bytes);

while (start < end) {
int64_t next_zero, chunk_end, status_bytes;
while (bytes) {
int64_t next_zero, cur_bytes, status_bytes;

if (!bdrv_dirty_bitmap_get(s->copy_bitmap, start)) {
trace_block_copy_skip(s, start);
start += s->cluster_size;
bytes -= s->cluster_size;
continue; /* already copied */
}

chunk_end = MIN(end, start + s->copy_size);
cur_bytes = MIN(bytes, s->copy_size);

next_zero = bdrv_dirty_bitmap_next_zero(s->copy_bitmap, start,
chunk_end - start);
cur_bytes);
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;
assert(next_zero < start + cur_bytes); /* no need to do MIN() */
cur_bytes = next_zero - start;
}

ret = block_copy_block_status(s, start, chunk_end - start,
&status_bytes);
ret = block_copy_block_status(s, start, cur_bytes, &status_bytes);
if (s->skip_unallocated && !(ret & BDRV_BLOCK_ALLOCATED)) {
bdrv_reset_dirty_bitmap(s->copy_bitmap, start, status_bytes);
progress_set_remaining(s->progress,
bdrv_get_dirty_count(s->copy_bitmap) +
s->in_flight_bytes);
trace_block_copy_skip_range(s, start, status_bytes);
start += status_bytes;
bytes -= status_bytes;
continue;
}

chunk_end = MIN(chunk_end, start + status_bytes);
cur_bytes = MIN(cur_bytes, status_bytes);

trace_block_copy_process(s, start);

bdrv_reset_dirty_bitmap(s->copy_bitmap, start, chunk_end - start);
s->in_flight_bytes += chunk_end - start;
bdrv_reset_dirty_bitmap(s->copy_bitmap, start, cur_bytes);
s->in_flight_bytes += cur_bytes;

co_get_from_shres(s->mem, chunk_end - start);
ret = block_copy_do_copy(s, start, chunk_end, ret & BDRV_BLOCK_ZERO,
co_get_from_shres(s->mem, cur_bytes);
ret = block_copy_do_copy(s, start, cur_bytes, ret & BDRV_BLOCK_ZERO,
error_is_read);
co_put_to_shres(s->mem, chunk_end - start);
s->in_flight_bytes -= chunk_end - start;
co_put_to_shres(s->mem, cur_bytes);
s->in_flight_bytes -= cur_bytes;
if (ret < 0) {
bdrv_set_dirty_bitmap(s->copy_bitmap, start, chunk_end - start);
bdrv_set_dirty_bitmap(s->copy_bitmap, start, cur_bytes);
break;
}

progress_work_done(s->progress, chunk_end - start);
s->progress_bytes_callback(chunk_end - start, s->progress_opaque);
start = chunk_end;
ret = 0;
progress_work_done(s->progress, cur_bytes);
s->progress_bytes_callback(cur_bytes, s->progress_opaque);
start += cur_bytes;
bytes -= cur_bytes;
}

block_copy_inflight_req_end(&req);
Expand Down
6 changes: 3 additions & 3 deletions include/block/block-copy.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -19,8 +19,8 @@
#include "qemu/co-shared-resource.h"

typedef struct BlockCopyInFlightReq {
int64_t start_byte;
int64_t end_byte;
int64_t start;
int64_t bytes;
QLIST_ENTRY(BlockCopyInFlightReq) list;
CoQueue wait_queue; /* coroutines blocked on this request */
} BlockCopyInFlightReq;
Expand Down Expand Up @@ -85,7 +85,7 @@ void block_copy_state_free(BlockCopyState *s);
int64_t block_copy_reset_unallocated(BlockCopyState *s,
int64_t offset, int64_t *count);

int coroutine_fn block_copy(BlockCopyState *s, int64_t start, uint64_t bytes,
int coroutine_fn block_copy(BlockCopyState *s, int64_t start, int64_t bytes,
bool *error_is_read);

#endif /* BLOCK_COPY_H */

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