*/
#include "trace.h"
-#include "blockjob.h"
-#include "block_int.h"
+#include "block/blockjob.h"
+#include "block/block_int.h"
#include "qemu/ratelimit.h"
+#include "qemu/bitmap.h"
-enum {
- /*
- * Size of data buffer for populating the image file. This should be large
- * enough to process multiple clusters in a single call, so that populating
- * contiguous regions of the image is efficient.
- */
- BLOCK_SIZE = 512 * BDRV_SECTORS_PER_DIRTY_CHUNK, /* in bytes */
-};
+#define SLICE_TIME 100000000ULL /* ns */
+#define MAX_IN_FLIGHT 16
-#define SLICE_TIME 100000000ULL /* ns */
+/* The mirroring buffer is a list of granularity-sized chunks.
+ * Free chunks are organized in a list.
+ */
+typedef struct MirrorBuffer {
+ QSIMPLEQ_ENTRY(MirrorBuffer) next;
+} MirrorBuffer;
typedef struct MirrorBlockJob {
BlockJob common;
RateLimit limit;
BlockDriverState *target;
MirrorSyncMode mode;
+ BlockdevOnError on_source_error, on_target_error;
+ bool synced;
+ bool should_complete;
int64_t sector_num;
+ int64_t granularity;
+ size_t buf_size;
+ unsigned long *cow_bitmap;
+ HBitmapIter hbi;
uint8_t *buf;
+ QSIMPLEQ_HEAD(, MirrorBuffer) buf_free;
+ int buf_free_count;
+
+ unsigned long *in_flight_bitmap;
+ int in_flight;
+ int ret;
} MirrorBlockJob;
-static int coroutine_fn mirror_iteration(MirrorBlockJob *s)
+typedef struct MirrorOp {
+ MirrorBlockJob *s;
+ QEMUIOVector qiov;
+ int64_t sector_num;
+ int nb_sectors;
+} MirrorOp;
+
+static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read,
+ int error)
+{
+ s->synced = false;
+ if (read) {
+ return block_job_error_action(&s->common, s->common.bs,
+ s->on_source_error, true, error);
+ } else {
+ return block_job_error_action(&s->common, s->target,
+ s->on_target_error, false, error);
+ }
+}
+
+static void mirror_iteration_done(MirrorOp *op, int ret)
+{
+ MirrorBlockJob *s = op->s;
+ struct iovec *iov;
+ int64_t chunk_num;
+ int i, nb_chunks, sectors_per_chunk;
+
+ trace_mirror_iteration_done(s, op->sector_num, op->nb_sectors, ret);
+
+ s->in_flight--;
+ iov = op->qiov.iov;
+ for (i = 0; i < op->qiov.niov; i++) {
+ MirrorBuffer *buf = (MirrorBuffer *) iov[i].iov_base;
+ QSIMPLEQ_INSERT_TAIL(&s->buf_free, buf, next);
+ s->buf_free_count++;
+ }
+
+ sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
+ chunk_num = op->sector_num / sectors_per_chunk;
+ nb_chunks = op->nb_sectors / sectors_per_chunk;
+ bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks);
+ if (s->cow_bitmap && ret >= 0) {
+ bitmap_set(s->cow_bitmap, chunk_num, nb_chunks);
+ }
+
+ g_slice_free(MirrorOp, op);
+ qemu_coroutine_enter(s->common.co, NULL);
+}
+
+static void mirror_write_complete(void *opaque, int ret)
+{
+ MirrorOp *op = opaque;
+ MirrorBlockJob *s = op->s;
+ if (ret < 0) {
+ BlockDriverState *source = s->common.bs;
+ BlockErrorAction action;
+
+ bdrv_set_dirty(source, op->sector_num, op->nb_sectors);
+ action = mirror_error_action(s, false, -ret);
+ if (action == BDRV_ACTION_REPORT && s->ret >= 0) {
+ s->ret = ret;
+ }
+ }
+ mirror_iteration_done(op, ret);
+}
+
+static void mirror_read_complete(void *opaque, int ret)
+{
+ MirrorOp *op = opaque;
+ MirrorBlockJob *s = op->s;
+ if (ret < 0) {
+ BlockDriverState *source = s->common.bs;
+ BlockErrorAction action;
+
+ bdrv_set_dirty(source, op->sector_num, op->nb_sectors);
+ action = mirror_error_action(s, true, -ret);
+ if (action == BDRV_ACTION_REPORT && s->ret >= 0) {
+ s->ret = ret;
+ }
+
+ mirror_iteration_done(op, ret);
+ return;
+ }
+ bdrv_aio_writev(s->target, op->sector_num, &op->qiov, op->nb_sectors,
+ mirror_write_complete, op);
+}
+
+static void coroutine_fn mirror_iteration(MirrorBlockJob *s)
{
BlockDriverState *source = s->common.bs;
- BlockDriverState *target = s->target;
- QEMUIOVector qiov;
- int ret, nb_sectors;
- int64_t end;
- struct iovec iov;
+ int nb_sectors, sectors_per_chunk, nb_chunks;
+ int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector;
+ MirrorOp *op;
+ s->sector_num = hbitmap_iter_next(&s->hbi);
+ if (s->sector_num < 0) {
+ bdrv_dirty_iter_init(source, &s->hbi);
+ s->sector_num = hbitmap_iter_next(&s->hbi);
+ trace_mirror_restart_iter(s, bdrv_get_dirty_count(source));
+ assert(s->sector_num >= 0);
+ }
+
+ hbitmap_next_sector = s->sector_num;
+ sector_num = s->sector_num;
+ sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
end = s->common.len >> BDRV_SECTOR_BITS;
- s->sector_num = bdrv_get_next_dirty(source, s->sector_num);
- nb_sectors = MIN(BDRV_SECTORS_PER_DIRTY_CHUNK, end - s->sector_num);
- bdrv_reset_dirty(source, s->sector_num, nb_sectors);
+
+ /* Extend the QEMUIOVector to include all adjacent blocks that will
+ * be copied in this operation.
+ *
+ * We have to do this if we have no backing file yet in the destination,
+ * and the cluster size is very large. Then we need to do COW ourselves.
+ * The first time a cluster is copied, copy it entirely. Note that,
+ * because both the granularity and the cluster size are powers of two,
+ * the number of sectors to copy cannot exceed one cluster.
+ *
+ * We also want to extend the QEMUIOVector to include more adjacent
+ * dirty blocks if possible, to limit the number of I/O operations and
+ * run efficiently even with a small granularity.
+ */
+ nb_chunks = 0;
+ nb_sectors = 0;
+ next_sector = sector_num;
+ next_chunk = sector_num / sectors_per_chunk;
+
+ /* Wait for I/O to this cluster (from a previous iteration) to be done. */
+ while (test_bit(next_chunk, s->in_flight_bitmap)) {
+ trace_mirror_yield_in_flight(s, sector_num, s->in_flight);
+ qemu_coroutine_yield();
+ }
+
+ do {
+ int added_sectors, added_chunks;
+
+ if (!bdrv_get_dirty(source, next_sector) ||
+ test_bit(next_chunk, s->in_flight_bitmap)) {
+ assert(nb_sectors > 0);
+ break;
+ }
+
+ added_sectors = sectors_per_chunk;
+ if (s->cow_bitmap && !test_bit(next_chunk, s->cow_bitmap)) {
+ bdrv_round_to_clusters(s->target,
+ next_sector, added_sectors,
+ &next_sector, &added_sectors);
+
+ /* On the first iteration, the rounding may make us copy
+ * sectors before the first dirty one.
+ */
+ if (next_sector < sector_num) {
+ assert(nb_sectors == 0);
+ sector_num = next_sector;
+ next_chunk = next_sector / sectors_per_chunk;
+ }
+ }
+
+ added_sectors = MIN(added_sectors, end - (sector_num + nb_sectors));
+ added_chunks = (added_sectors + sectors_per_chunk - 1) / sectors_per_chunk;
+
+ /* When doing COW, it may happen that there is not enough space for
+ * a full cluster. Wait if that is the case.
+ */
+ while (nb_chunks == 0 && s->buf_free_count < added_chunks) {
+ trace_mirror_yield_buf_busy(s, nb_chunks, s->in_flight);
+ qemu_coroutine_yield();
+ }
+ if (s->buf_free_count < nb_chunks + added_chunks) {
+ trace_mirror_break_buf_busy(s, nb_chunks, s->in_flight);
+ break;
+ }
+
+ /* We have enough free space to copy these sectors. */
+ bitmap_set(s->in_flight_bitmap, next_chunk, added_chunks);
+
+ nb_sectors += added_sectors;
+ nb_chunks += added_chunks;
+ next_sector += added_sectors;
+ next_chunk += added_chunks;
+ } while (next_sector < end);
+
+ /* Allocate a MirrorOp that is used as an AIO callback. */
+ op = g_slice_new(MirrorOp);
+ op->s = s;
+ op->sector_num = sector_num;
+ op->nb_sectors = nb_sectors;
+
+ /* Now make a QEMUIOVector taking enough granularity-sized chunks
+ * from s->buf_free.
+ */
+ qemu_iovec_init(&op->qiov, nb_chunks);
+ next_sector = sector_num;
+ while (nb_chunks-- > 0) {
+ MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free);
+ QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next);
+ s->buf_free_count--;
+ qemu_iovec_add(&op->qiov, buf, s->granularity);
+
+ /* Advance the HBitmapIter in parallel, so that we do not examine
+ * the same sector twice.
+ */
+ if (next_sector > hbitmap_next_sector && bdrv_get_dirty(source, next_sector)) {
+ hbitmap_next_sector = hbitmap_iter_next(&s->hbi);
+ }
+
+ next_sector += sectors_per_chunk;
+ }
+
+ bdrv_reset_dirty(source, sector_num, nb_sectors);
/* Copy the dirty cluster. */
- iov.iov_base = s->buf;
- iov.iov_len = nb_sectors * 512;
- qemu_iovec_init_external(&qiov, &iov, 1);
+ s->in_flight++;
+ trace_mirror_one_iteration(s, sector_num, nb_sectors);
+ bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors,
+ mirror_read_complete, op);
+}
- trace_mirror_one_iteration(s, s->sector_num, nb_sectors);
- ret = bdrv_co_readv(source, s->sector_num, nb_sectors, &qiov);
- if (ret < 0) {
- return ret;
+static void mirror_free_init(MirrorBlockJob *s)
+{
+ int granularity = s->granularity;
+ size_t buf_size = s->buf_size;
+ uint8_t *buf = s->buf;
+
+ assert(s->buf_free_count == 0);
+ QSIMPLEQ_INIT(&s->buf_free);
+ while (buf_size != 0) {
+ MirrorBuffer *cur = (MirrorBuffer *)buf;
+ QSIMPLEQ_INSERT_TAIL(&s->buf_free, cur, next);
+ s->buf_free_count++;
+ buf_size -= granularity;
+ buf += granularity;
+ }
+}
+
+static void mirror_drain(MirrorBlockJob *s)
+{
+ while (s->in_flight > 0) {
+ qemu_coroutine_yield();
}
- return bdrv_co_writev(target, s->sector_num, nb_sectors, &qiov);
}
static void coroutine_fn mirror_run(void *opaque)
{
MirrorBlockJob *s = opaque;
BlockDriverState *bs = s->common.bs;
- int64_t sector_num, end;
+ int64_t sector_num, end, sectors_per_chunk, length;
+ uint64_t last_pause_ns;
+ BlockDriverInfo bdi;
+ char backing_filename[1024];
int ret = 0;
int n;
- bool synced = false;
if (block_job_is_cancelled(&s->common)) {
goto immediate_exit;
}
s->common.len = bdrv_getlength(bs);
- if (s->common.len < 0) {
+ if (s->common.len <= 0) {
block_job_completed(&s->common, s->common.len);
return;
}
+ length = (bdrv_getlength(bs) + s->granularity - 1) / s->granularity;
+ s->in_flight_bitmap = bitmap_new(length);
+
+ /* If we have no backing file yet in the destination, we cannot let
+ * the destination do COW. Instead, we copy sectors around the
+ * dirty data if needed. We need a bitmap to do that.
+ */
+ bdrv_get_backing_filename(s->target, backing_filename,
+ sizeof(backing_filename));
+ if (backing_filename[0] && !s->target->backing_hd) {
+ bdrv_get_info(s->target, &bdi);
+ if (s->granularity < bdi.cluster_size) {
+ s->buf_size = MAX(s->buf_size, bdi.cluster_size);
+ s->cow_bitmap = bitmap_new(length);
+ }
+ }
+
end = s->common.len >> BDRV_SECTOR_BITS;
- s->buf = qemu_blockalign(bs, BLOCK_SIZE);
+ s->buf = qemu_blockalign(bs, s->buf_size);
+ sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
+ mirror_free_init(s);
if (s->mode != MIRROR_SYNC_MODE_NONE) {
/* First part, loop on the sectors and initialize the dirty bitmap. */
BlockDriverState *base;
base = s->mode == MIRROR_SYNC_MODE_FULL ? NULL : bs->backing_hd;
for (sector_num = 0; sector_num < end; ) {
- int64_t next = (sector_num | (BDRV_SECTORS_PER_DIRTY_CHUNK - 1)) + 1;
+ int64_t next = (sector_num | (sectors_per_chunk - 1)) + 1;
ret = bdrv_co_is_allocated_above(bs, base,
sector_num, next - sector_num, &n);
}
}
- s->sector_num = -1;
+ bdrv_dirty_iter_init(bs, &s->hbi);
+ last_pause_ns = qemu_get_clock_ns(rt_clock);
for (;;) {
uint64_t delay_ns;
int64_t cnt;
bool should_complete;
+ if (s->ret < 0) {
+ ret = s->ret;
+ goto immediate_exit;
+ }
+
cnt = bdrv_get_dirty_count(bs);
- if (cnt != 0) {
- ret = mirror_iteration(s);
- if (ret < 0) {
- goto immediate_exit;
+
+ /* Note that even when no rate limit is applied we need to yield
+ * periodically with no pending I/O so that qemu_aio_flush() returns.
+ * We do so every SLICE_TIME nanoseconds, or when there is an error,
+ * or when the source is clean, whichever comes first.
+ */
+ if (qemu_get_clock_ns(rt_clock) - last_pause_ns < SLICE_TIME &&
+ s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
+ if (s->in_flight == MAX_IN_FLIGHT || s->buf_free_count == 0 ||
+ (cnt == 0 && s->in_flight > 0)) {
+ trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt);
+ qemu_coroutine_yield();
+ continue;
+ } else if (cnt != 0) {
+ mirror_iteration(s);
+ continue;
}
- cnt = bdrv_get_dirty_count(bs);
}
should_complete = false;
- if (cnt == 0) {
+ if (s->in_flight == 0 && cnt == 0) {
trace_mirror_before_flush(s);
ret = bdrv_flush(s->target);
if (ret < 0) {
- goto immediate_exit;
- }
+ if (mirror_error_action(s, false, -ret) == BDRV_ACTION_REPORT) {
+ goto immediate_exit;
+ }
+ } else {
+ /* We're out of the streaming phase. From now on, if the job
+ * is cancelled we will actually complete all pending I/O and
+ * report completion. This way, block-job-cancel will leave
+ * the target in a consistent state.
+ */
+ s->common.offset = end * BDRV_SECTOR_SIZE;
+ if (!s->synced) {
+ block_job_ready(&s->common);
+ s->synced = true;
+ }
- /* We're out of the streaming phase. From now on, if the job
- * is cancelled we will actually complete all pending I/O and
- * report completion. This way, block-job-cancel will leave
- * the target in a consistent state.
- */
- synced = true;
- s->common.offset = end * BDRV_SECTOR_SIZE;
- should_complete = block_job_is_cancelled(&s->common);
- cnt = bdrv_get_dirty_count(bs);
+ should_complete = s->should_complete ||
+ block_job_is_cancelled(&s->common);
+ cnt = bdrv_get_dirty_count(bs);
+ }
}
if (cnt == 0 && should_complete) {
}
ret = 0;
- trace_mirror_before_sleep(s, cnt, synced);
- if (!synced) {
+ trace_mirror_before_sleep(s, cnt, s->synced);
+ if (!s->synced) {
/* Publish progress */
- s->common.offset = end * BDRV_SECTOR_SIZE - cnt * BLOCK_SIZE;
+ s->common.offset = (end - cnt) * BDRV_SECTOR_SIZE;
if (s->common.speed) {
- delay_ns = ratelimit_calculate_delay(&s->limit, BDRV_SECTORS_PER_DIRTY_CHUNK);
+ delay_ns = ratelimit_calculate_delay(&s->limit, sectors_per_chunk);
} else {
delay_ns = 0;
}
- /* Note that even when no rate limit is applied we need to yield
- * with no pending I/O here so that qemu_aio_flush() returns.
- */
block_job_sleep_ns(&s->common, rt_clock, delay_ns);
if (block_job_is_cancelled(&s->common)) {
break;
}
} else if (!should_complete) {
- delay_ns = (cnt == 0 ? SLICE_TIME : 0);
+ delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0);
block_job_sleep_ns(&s->common, rt_clock, delay_ns);
} else if (cnt == 0) {
/* The two disks are in sync. Exit and report successful
s->common.cancelled = false;
break;
}
+ last_pause_ns = qemu_get_clock_ns(rt_clock);
}
immediate_exit:
- g_free(s->buf);
- bdrv_set_dirty_tracking(bs, false);
+ if (s->in_flight > 0) {
+ /* We get here only if something went wrong. Either the job failed,
+ * or it was cancelled prematurely so that we do not guarantee that
+ * the target is a copy of the source.
+ */
+ assert(ret < 0 || (!s->synced && block_job_is_cancelled(&s->common)));
+ mirror_drain(s);
+ }
+
+ assert(s->in_flight == 0);
+ qemu_vfree(s->buf);
+ g_free(s->cow_bitmap);
+ g_free(s->in_flight_bitmap);
+ bdrv_set_dirty_tracking(bs, 0);
+ bdrv_iostatus_disable(s->target);
+ if (s->should_complete && ret == 0) {
+ if (bdrv_get_flags(s->target) != bdrv_get_flags(s->common.bs)) {
+ bdrv_reopen(s->target, bdrv_get_flags(s->common.bs), NULL);
+ }
+ bdrv_swap(s->target, s->common.bs);
+ }
bdrv_close(s->target);
bdrv_delete(s->target);
block_job_completed(&s->common, ret);
ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME);
}
+static void mirror_iostatus_reset(BlockJob *job)
+{
+ MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
+
+ bdrv_iostatus_reset(s->target);
+}
+
+static void mirror_complete(BlockJob *job, Error **errp)
+{
+ MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
+ int ret;
+
+ ret = bdrv_open_backing_file(s->target, NULL);
+ if (ret < 0) {
+ char backing_filename[PATH_MAX];
+ bdrv_get_full_backing_filename(s->target, backing_filename,
+ sizeof(backing_filename));
+ error_set(errp, QERR_OPEN_FILE_FAILED, backing_filename);
+ return;
+ }
+ if (!s->synced) {
+ error_set(errp, QERR_BLOCK_JOB_NOT_READY, job->bs->device_name);
+ return;
+ }
+
+ s->should_complete = true;
+ block_job_resume(job);
+}
+
static BlockJobType mirror_job_type = {
.instance_size = sizeof(MirrorBlockJob),
.job_type = "mirror",
.set_speed = mirror_set_speed,
+ .iostatus_reset= mirror_iostatus_reset,
+ .complete = mirror_complete,
};
void mirror_start(BlockDriverState *bs, BlockDriverState *target,
- int64_t speed, MirrorSyncMode mode,
+ int64_t speed, int64_t granularity, int64_t buf_size,
+ MirrorSyncMode mode, BlockdevOnError on_source_error,
+ BlockdevOnError on_target_error,
BlockDriverCompletionFunc *cb,
void *opaque, Error **errp)
{
MirrorBlockJob *s;
+ if (granularity == 0) {
+ /* Choose the default granularity based on the target file's cluster
+ * size, clamped between 4k and 64k. */
+ BlockDriverInfo bdi;
+ if (bdrv_get_info(target, &bdi) >= 0 && bdi.cluster_size != 0) {
+ granularity = MAX(4096, bdi.cluster_size);
+ granularity = MIN(65536, granularity);
+ } else {
+ granularity = 65536;
+ }
+ }
+
+ assert ((granularity & (granularity - 1)) == 0);
+
+ if ((on_source_error == BLOCKDEV_ON_ERROR_STOP ||
+ on_source_error == BLOCKDEV_ON_ERROR_ENOSPC) &&
+ !bdrv_iostatus_is_enabled(bs)) {
+ error_set(errp, QERR_INVALID_PARAMETER, "on-source-error");
+ return;
+ }
+
s = block_job_create(&mirror_job_type, bs, speed, cb, opaque, errp);
if (!s) {
return;
}
+ s->on_source_error = on_source_error;
+ s->on_target_error = on_target_error;
s->target = target;
s->mode = mode;
- bdrv_set_dirty_tracking(bs, true);
+ s->granularity = granularity;
+ s->buf_size = MAX(buf_size, granularity);
+
+ bdrv_set_dirty_tracking(bs, granularity);
bdrv_set_enable_write_cache(s->target, true);
+ bdrv_set_on_error(s->target, on_target_error, on_target_error);
+ bdrv_iostatus_enable(s->target);
s->common.co = qemu_coroutine_create(mirror_run);
trace_mirror_start(bs, s, s->common.co, opaque);
qemu_coroutine_enter(s->common.co, s);
projects / qemu.git / blobdiff