/* * Image mirroring * * Copyright Red Hat, Inc. 2012 * * Authors: * Paolo Bonzini * * This work is licensed under the terms of the GNU LGPL, version 2 or later. * See the COPYING.LIB file in the top-level directory. * */ #include "qemu/osdep.h" #include "trace.h" #include "block/blockjob.h" #include "block/block_int.h" #include "sysemu/block-backend.h" #include "qapi/error.h" #include "qapi/qmp/qerror.h" #include "qemu/ratelimit.h" #include "qemu/bitmap.h" #include "qemu/error-report.h" #define SLICE_TIME 100000000ULL /* ns */ #define MAX_IN_FLIGHT 16 #define DEFAULT_MIRROR_BUF_SIZE (10 << 20) /* 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; BlockDriverState *base; /* The name of the graph node to replace */ char *replaces; /* The BDS to replace */ BlockDriverState *to_replace; /* Used to block operations on the drive-mirror-replace target */ Error *replace_blocker; bool is_none_mode; BlockdevOnError on_source_error, on_target_error; bool synced; bool should_complete; int64_t granularity; size_t buf_size; int64_t bdev_length; unsigned long *cow_bitmap; BdrvDirtyBitmap *dirty_bitmap; HBitmapIter hbi; uint8_t *buf; QSIMPLEQ_HEAD(, MirrorBuffer) buf_free; int buf_free_count; unsigned long *in_flight_bitmap; int in_flight; int sectors_in_flight; int ret; bool unmap; bool waiting_for_io; int target_cluster_sectors; int max_iov; } MirrorBlockJob; 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->on_source_error, true, error); } else { return block_job_error_action(&s->common, 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--; s->sectors_in_flight -= op->nb_sectors; 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 = DIV_ROUND_UP(op->nb_sectors, sectors_per_chunk); bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks); if (ret >= 0) { if (s->cow_bitmap) { bitmap_set(s->cow_bitmap, chunk_num, nb_chunks); } s->common.offset += (uint64_t)op->nb_sectors * BDRV_SECTOR_SIZE; } qemu_iovec_destroy(&op->qiov); g_free(op); if (s->waiting_for_io) { 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) { BlockErrorAction action; bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors); action = mirror_error_action(s, false, -ret); if (action == BLOCK_ERROR_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) { BlockErrorAction action; bdrv_set_dirty_bitmap(s->dirty_bitmap, op->sector_num, op->nb_sectors); action = mirror_error_action(s, true, -ret); if (action == BLOCK_ERROR_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 inline void mirror_clip_sectors(MirrorBlockJob *s, int64_t sector_num, int *nb_sectors) { *nb_sectors = MIN(*nb_sectors, s->bdev_length / BDRV_SECTOR_SIZE - sector_num); } /* Round sector_num and/or nb_sectors to target cluster if COW is needed, and * return the offset of the adjusted tail sector against original. */ static int mirror_cow_align(MirrorBlockJob *s, int64_t *sector_num, int *nb_sectors) { bool need_cow; int ret = 0; int chunk_sectors = s->granularity >> BDRV_SECTOR_BITS; int64_t align_sector_num = *sector_num; int align_nb_sectors = *nb_sectors; int max_sectors = chunk_sectors * s->max_iov; need_cow = !test_bit(*sector_num / chunk_sectors, s->cow_bitmap); need_cow |= !test_bit((*sector_num + *nb_sectors - 1) / chunk_sectors, s->cow_bitmap); if (need_cow) { bdrv_round_to_clusters(s->target, *sector_num, *nb_sectors, &align_sector_num, &align_nb_sectors); } if (align_nb_sectors > max_sectors) { align_nb_sectors = max_sectors; if (need_cow) { align_nb_sectors = QEMU_ALIGN_DOWN(align_nb_sectors, s->target_cluster_sectors); } } /* Clipping may result in align_nb_sectors unaligned to chunk boundary, but * that doesn't matter because it's already the end of source image. */ mirror_clip_sectors(s, align_sector_num, &align_nb_sectors); ret = align_sector_num + align_nb_sectors - (*sector_num + *nb_sectors); *sector_num = align_sector_num; *nb_sectors = align_nb_sectors; assert(ret >= 0); return ret; } static inline void mirror_wait_for_io(MirrorBlockJob *s) { assert(!s->waiting_for_io); s->waiting_for_io = true; qemu_coroutine_yield(); s->waiting_for_io = false; } /* Submit async read while handling COW. * Returns: nb_sectors if no alignment is necessary, or * (new_end - sector_num) if tail is rounded up or down due to * alignment or buffer limit. */ static int mirror_do_read(MirrorBlockJob *s, int64_t sector_num, int nb_sectors) { BlockDriverState *source = s->common.bs; int sectors_per_chunk, nb_chunks; int ret = nb_sectors; MirrorOp *op; sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; /* We can only handle as much as buf_size at a time. */ nb_sectors = MIN(s->buf_size >> BDRV_SECTOR_BITS, nb_sectors); assert(nb_sectors); if (s->cow_bitmap) { ret += mirror_cow_align(s, §or_num, &nb_sectors); } assert(nb_sectors << BDRV_SECTOR_BITS <= s->buf_size); /* The sector range must meet granularity because: * 1) Caller passes in aligned values; * 2) mirror_cow_align is used only when target cluster is larger. */ assert(!(sector_num % sectors_per_chunk)); nb_chunks = DIV_ROUND_UP(nb_sectors, sectors_per_chunk); while (s->buf_free_count < nb_chunks) { trace_mirror_yield_in_flight(s, sector_num, s->in_flight); mirror_wait_for_io(s); } /* Allocate a MirrorOp that is used as an AIO callback. */ op = g_new(MirrorOp, 1); 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); while (nb_chunks-- > 0) { MirrorBuffer *buf = QSIMPLEQ_FIRST(&s->buf_free); size_t remaining = nb_sectors * BDRV_SECTOR_SIZE - op->qiov.size; QSIMPLEQ_REMOVE_HEAD(&s->buf_free, next); s->buf_free_count--; qemu_iovec_add(&op->qiov, buf, MIN(s->granularity, remaining)); } /* Copy the dirty cluster. */ s->in_flight++; s->sectors_in_flight += nb_sectors; trace_mirror_one_iteration(s, sector_num, nb_sectors); bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors, mirror_read_complete, op); return ret; } static void mirror_do_zero_or_discard(MirrorBlockJob *s, int64_t sector_num, int nb_sectors, bool is_discard) { MirrorOp *op; /* Allocate a MirrorOp that is used as an AIO callback. The qiov is zeroed * so the freeing in mirror_iteration_done is nop. */ op = g_new0(MirrorOp, 1); op->s = s; op->sector_num = sector_num; op->nb_sectors = nb_sectors; s->in_flight++; s->sectors_in_flight += nb_sectors; if (is_discard) { bdrv_aio_discard(s->target, sector_num, op->nb_sectors, mirror_write_complete, op); } else { bdrv_aio_write_zeroes(s->target, sector_num, op->nb_sectors, s->unmap ? BDRV_REQ_MAY_UNMAP : 0, mirror_write_complete, op); } } static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) { BlockDriverState *source = s->common.bs; int64_t sector_num, first_chunk; uint64_t delay_ns = 0; /* At least the first dirty chunk is mirrored in one iteration. */ int nb_chunks = 1; int64_t end = s->bdev_length / BDRV_SECTOR_SIZE; int sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; sector_num = hbitmap_iter_next(&s->hbi); if (sector_num < 0) { bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi); sector_num = hbitmap_iter_next(&s->hbi); trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap)); assert(sector_num >= 0); } first_chunk = sector_num / sectors_per_chunk; while (test_bit(first_chunk, s->in_flight_bitmap)) { trace_mirror_yield_in_flight(s, first_chunk, s->in_flight); mirror_wait_for_io(s); } /* Find the number of consective dirty chunks following the first dirty * one, and wait for in flight requests in them. */ while (nb_chunks * sectors_per_chunk < (s->buf_size >> BDRV_SECTOR_BITS)) { int64_t hbitmap_next; int64_t next_sector = sector_num + nb_chunks * sectors_per_chunk; int64_t next_chunk = next_sector / sectors_per_chunk; if (next_sector >= end || !bdrv_get_dirty(source, s->dirty_bitmap, next_sector)) { break; } if (test_bit(next_chunk, s->in_flight_bitmap)) { break; } hbitmap_next = hbitmap_iter_next(&s->hbi); if (hbitmap_next > next_sector || hbitmap_next < 0) { /* The bitmap iterator's cache is stale, refresh it */ bdrv_set_dirty_iter(&s->hbi, next_sector); hbitmap_next = hbitmap_iter_next(&s->hbi); } assert(hbitmap_next == next_sector); nb_chunks++; } /* Clear dirty bits before querying the block status, because * calling bdrv_get_block_status_above could yield - if some blocks are * marked dirty in this window, we need to know. */ bdrv_reset_dirty_bitmap(s->dirty_bitmap, sector_num, nb_chunks * sectors_per_chunk); bitmap_set(s->in_flight_bitmap, sector_num / sectors_per_chunk, nb_chunks); while (nb_chunks > 0 && sector_num < end) { int ret; int io_sectors; BlockDriverState *file; enum MirrorMethod { MIRROR_METHOD_COPY, MIRROR_METHOD_ZERO, MIRROR_METHOD_DISCARD } mirror_method = MIRROR_METHOD_COPY; assert(!(sector_num % sectors_per_chunk)); ret = bdrv_get_block_status_above(source, NULL, sector_num, nb_chunks * sectors_per_chunk, &io_sectors, &file); if (ret < 0) { io_sectors = nb_chunks * sectors_per_chunk; } io_sectors -= io_sectors % sectors_per_chunk; if (io_sectors < sectors_per_chunk) { io_sectors = sectors_per_chunk; } else if (ret >= 0 && !(ret & BDRV_BLOCK_DATA)) { int64_t target_sector_num; int target_nb_sectors; bdrv_round_to_clusters(s->target, sector_num, io_sectors, &target_sector_num, &target_nb_sectors); if (target_sector_num == sector_num && target_nb_sectors == io_sectors) { mirror_method = ret & BDRV_BLOCK_ZERO ? MIRROR_METHOD_ZERO : MIRROR_METHOD_DISCARD; } } mirror_clip_sectors(s, sector_num, &io_sectors); switch (mirror_method) { case MIRROR_METHOD_COPY: io_sectors = mirror_do_read(s, sector_num, io_sectors); break; case MIRROR_METHOD_ZERO: mirror_do_zero_or_discard(s, sector_num, io_sectors, false); break; case MIRROR_METHOD_DISCARD: mirror_do_zero_or_discard(s, sector_num, io_sectors, true); break; default: abort(); } assert(io_sectors); sector_num += io_sectors; nb_chunks -= DIV_ROUND_UP(io_sectors, sectors_per_chunk); delay_ns += ratelimit_calculate_delay(&s->limit, io_sectors); } return delay_ns; } 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) { mirror_wait_for_io(s); } } typedef struct { int ret; } MirrorExitData; static void mirror_exit(BlockJob *job, void *opaque) { MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); MirrorExitData *data = opaque; AioContext *replace_aio_context = NULL; BlockDriverState *src = s->common.bs; /* Make sure that the source BDS doesn't go away before we called * block_job_completed(). */ bdrv_ref(src); if (s->to_replace) { replace_aio_context = bdrv_get_aio_context(s->to_replace); aio_context_acquire(replace_aio_context); } if (s->should_complete && data->ret == 0) { BlockDriverState *to_replace = s->common.bs; if (s->to_replace) { to_replace = s->to_replace; } /* This was checked in mirror_start_job(), but meanwhile one of the * nodes could have been newly attached to a BlockBackend. */ if (to_replace->blk && s->target->blk) { error_report("block job: Can't create node with two BlockBackends"); data->ret = -EINVAL; goto out; } if (bdrv_get_flags(s->target) != bdrv_get_flags(to_replace)) { bdrv_reopen(s->target, bdrv_get_flags(to_replace), NULL); } bdrv_replace_in_backing_chain(to_replace, s->target); } out: if (s->to_replace) { bdrv_op_unblock_all(s->to_replace, s->replace_blocker); error_free(s->replace_blocker); bdrv_unref(s->to_replace); } if (replace_aio_context) { aio_context_release(replace_aio_context); } g_free(s->replaces); bdrv_op_unblock_all(s->target, s->common.blocker); bdrv_unref(s->target); block_job_completed(&s->common, data->ret); g_free(data); bdrv_drained_end(src); if (qemu_get_aio_context() == bdrv_get_aio_context(src)) { aio_enable_external(iohandler_get_aio_context()); } bdrv_unref(src); } static void coroutine_fn mirror_run(void *opaque) { MirrorBlockJob *s = opaque; MirrorExitData *data; BlockDriverState *bs = s->common.bs; int64_t sector_num, end, length; uint64_t last_pause_ns; BlockDriverInfo bdi; char backing_filename[2]; /* we only need 2 characters because we are only checking for a NULL string */ int ret = 0; int n; int target_cluster_size = BDRV_SECTOR_SIZE; if (block_job_is_cancelled(&s->common)) { goto immediate_exit; } s->bdev_length = bdrv_getlength(bs); if (s->bdev_length < 0) { ret = s->bdev_length; goto immediate_exit; } else if (s->bdev_length == 0) { /* Report BLOCK_JOB_READY and wait for complete. */ block_job_event_ready(&s->common); s->synced = true; while (!block_job_is_cancelled(&s->common) && !s->should_complete) { block_job_yield(&s->common); } s->common.cancelled = false; goto immediate_exit; } length = DIV_ROUND_UP(s->bdev_length, 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 (!bdrv_get_info(s->target, &bdi) && bdi.cluster_size) { target_cluster_size = bdi.cluster_size; } if (backing_filename[0] && !s->target->backing && s->granularity < target_cluster_size) { s->buf_size = MAX(s->buf_size, target_cluster_size); s->cow_bitmap = bitmap_new(length); } s->target_cluster_sectors = target_cluster_size >> BDRV_SECTOR_BITS; s->max_iov = MIN(s->common.bs->bl.max_iov, s->target->bl.max_iov); end = s->bdev_length / BDRV_SECTOR_SIZE; s->buf = qemu_try_blockalign(bs, s->buf_size); if (s->buf == NULL) { ret = -ENOMEM; goto immediate_exit; } mirror_free_init(s); last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); if (!s->is_none_mode) { /* First part, loop on the sectors and initialize the dirty bitmap. */ BlockDriverState *base = s->base; bool mark_all_dirty = s->base == NULL && !bdrv_has_zero_init(s->target); for (sector_num = 0; sector_num < end; ) { /* Just to make sure we are not exceeding int limit. */ int nb_sectors = MIN(INT_MAX >> BDRV_SECTOR_BITS, end - sector_num); int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); if (now - last_pause_ns > SLICE_TIME) { last_pause_ns = now; block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, 0); } if (block_job_is_cancelled(&s->common)) { goto immediate_exit; } ret = bdrv_is_allocated_above(bs, base, sector_num, nb_sectors, &n); if (ret < 0) { goto immediate_exit; } assert(n > 0); if (ret == 1 || mark_all_dirty) { bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n); } sector_num += n; } } bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi); for (;;) { uint64_t delay_ns = 0; int64_t cnt; bool should_complete; if (s->ret < 0) { ret = s->ret; goto immediate_exit; } cnt = bdrv_get_dirty_count(s->dirty_bitmap); /* s->common.offset contains the number of bytes already processed so * far, cnt is the number of dirty sectors remaining and * s->sectors_in_flight is the number of sectors currently being * processed; together those are the current total operation length */ s->common.len = s->common.offset + (cnt + s->sectors_in_flight) * BDRV_SECTOR_SIZE; /* Note that even when no rate limit is applied we need to yield * periodically with no pending I/O so that bdrv_drain_all() 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_clock_get_ns(QEMU_CLOCK_REALTIME) - 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); mirror_wait_for_io(s); continue; } else if (cnt != 0) { delay_ns = mirror_iteration(s); } } should_complete = false; if (s->in_flight == 0 && cnt == 0) { trace_mirror_before_flush(s); ret = bdrv_flush(s->target); if (ret < 0) { if (mirror_error_action(s, false, -ret) == BLOCK_ERROR_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. */ if (!s->synced) { block_job_event_ready(&s->common); s->synced = true; } should_complete = s->should_complete || block_job_is_cancelled(&s->common); cnt = bdrv_get_dirty_count(s->dirty_bitmap); } } if (cnt == 0 && should_complete) { /* The dirty bitmap is not updated while operations are pending. * If we're about to exit, wait for pending operations before * calling bdrv_get_dirty_count(bs), or we may exit while the * source has dirty data to copy! * * Note that I/O can be submitted by the guest while * mirror_populate runs. */ trace_mirror_before_drain(s, cnt); bdrv_co_drain(bs); cnt = bdrv_get_dirty_count(s->dirty_bitmap); } ret = 0; trace_mirror_before_sleep(s, cnt, s->synced, delay_ns); if (!s->synced) { block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); if (block_job_is_cancelled(&s->common)) { break; } } else if (!should_complete) { delay_ns = (s->in_flight == 0 && cnt == 0 ? SLICE_TIME : 0); block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns); } else if (cnt == 0) { /* The two disks are in sync. Exit and report successful * completion. */ assert(QLIST_EMPTY(&bs->tracked_requests)); s->common.cancelled = false; break; } last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); } immediate_exit: 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_release_dirty_bitmap(bs, s->dirty_bitmap); data = g_malloc(sizeof(*data)); data->ret = ret; /* Before we switch to target in mirror_exit, make sure data doesn't * change. */ bdrv_drained_begin(s->common.bs); if (qemu_get_aio_context() == bdrv_get_aio_context(bs)) { /* FIXME: virtio host notifiers run on iohandler_ctx, therefore the * above bdrv_drained_end isn't enough to quiesce it. This is ugly, we * need a block layer API change to achieve this. */ aio_disable_external(iohandler_get_aio_context()); } block_job_defer_to_main_loop(&s->common, mirror_exit, data); } static void mirror_set_speed(BlockJob *job, int64_t speed, Error **errp) { MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); if (speed < 0) { error_setg(errp, QERR_INVALID_PARAMETER, "speed"); return; } ratelimit_set_speed(&s->limit, speed / BDRV_SECTOR_SIZE, SLICE_TIME); } static void mirror_complete(BlockJob *job, Error **errp) { MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); Error *local_err = NULL; int ret; ret = bdrv_open_backing_file(s->target, NULL, "backing", &local_err); if (ret < 0) { error_propagate(errp, local_err); return; } if (!s->synced) { error_setg(errp, QERR_BLOCK_JOB_NOT_READY, job->id); return; } /* check the target bs is not blocked and block all operations on it */ if (s->replaces) { AioContext *replace_aio_context; s->to_replace = bdrv_find_node(s->replaces); if (!s->to_replace) { error_setg(errp, "Node name '%s' not found", s->replaces); return; } replace_aio_context = bdrv_get_aio_context(s->to_replace); aio_context_acquire(replace_aio_context); error_setg(&s->replace_blocker, "block device is in use by block-job-complete"); bdrv_op_block_all(s->to_replace, s->replace_blocker); bdrv_ref(s->to_replace); aio_context_release(replace_aio_context); } s->should_complete = true; block_job_enter(&s->common); } static const BlockJobDriver mirror_job_driver = { .instance_size = sizeof(MirrorBlockJob), .job_type = BLOCK_JOB_TYPE_MIRROR, .set_speed = mirror_set_speed, .complete = mirror_complete, }; static const BlockJobDriver commit_active_job_driver = { .instance_size = sizeof(MirrorBlockJob), .job_type = BLOCK_JOB_TYPE_COMMIT, .set_speed = mirror_set_speed, .complete = mirror_complete, }; static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target, const char *replaces, int64_t speed, uint32_t granularity, int64_t buf_size, BlockdevOnError on_source_error, BlockdevOnError on_target_error, bool unmap, BlockCompletionFunc *cb, void *opaque, Error **errp, const BlockJobDriver *driver, bool is_none_mode, BlockDriverState *base) { MirrorBlockJob *s; BlockDriverState *replaced_bs; if (granularity == 0) { granularity = bdrv_get_default_bitmap_granularity(target); } assert ((granularity & (granularity - 1)) == 0); if (buf_size < 0) { error_setg(errp, "Invalid parameter 'buf-size'"); return; } if (buf_size == 0) { buf_size = DEFAULT_MIRROR_BUF_SIZE; } /* We can't support this case as long as the block layer can't handle * multiple BlockBackends per BlockDriverState. */ if (replaces) { replaced_bs = bdrv_lookup_bs(replaces, replaces, errp); if (replaced_bs == NULL) { return; } } else { replaced_bs = bs; } if (replaced_bs->blk && target->blk) { error_setg(errp, "Can't create node with two BlockBackends"); return; } s = block_job_create(driver, bs, speed, cb, opaque, errp); if (!s) { return; } s->replaces = g_strdup(replaces); s->on_source_error = on_source_error; s->on_target_error = on_target_error; s->target = target; s->is_none_mode = is_none_mode; s->base = base; s->granularity = granularity; s->buf_size = ROUND_UP(buf_size, granularity); s->unmap = unmap; s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp); if (!s->dirty_bitmap) { g_free(s->replaces); block_job_unref(&s->common); return; } bdrv_op_block_all(s->target, s->common.blocker); s->common.co = qemu_coroutine_create(mirror_run); trace_mirror_start(bs, s, s->common.co, opaque); qemu_coroutine_enter(s->common.co, s); } void mirror_start(BlockDriverState *bs, BlockDriverState *target, const char *replaces, int64_t speed, uint32_t granularity, int64_t buf_size, MirrorSyncMode mode, BlockdevOnError on_source_error, BlockdevOnError on_target_error, bool unmap, BlockCompletionFunc *cb, void *opaque, Error **errp) { bool is_none_mode; BlockDriverState *base; if (mode == MIRROR_SYNC_MODE_INCREMENTAL) { error_setg(errp, "Sync mode 'incremental' not supported"); return; } is_none_mode = mode == MIRROR_SYNC_MODE_NONE; base = mode == MIRROR_SYNC_MODE_TOP ? backing_bs(bs) : NULL; mirror_start_job(bs, target, replaces, speed, granularity, buf_size, on_source_error, on_target_error, unmap, cb, opaque, errp, &mirror_job_driver, is_none_mode, base); } void commit_active_start(BlockDriverState *bs, BlockDriverState *base, int64_t speed, BlockdevOnError on_error, BlockCompletionFunc *cb, void *opaque, Error **errp) { int64_t length, base_length; int orig_base_flags; int ret; Error *local_err = NULL; orig_base_flags = bdrv_get_flags(base); if (bdrv_reopen(base, bs->open_flags, errp)) { return; } length = bdrv_getlength(bs); if (length < 0) { error_setg_errno(errp, -length, "Unable to determine length of %s", bs->filename); goto error_restore_flags; } base_length = bdrv_getlength(base); if (base_length < 0) { error_setg_errno(errp, -base_length, "Unable to determine length of %s", base->filename); goto error_restore_flags; } if (length > base_length) { ret = bdrv_truncate(base, length); if (ret < 0) { error_setg_errno(errp, -ret, "Top image %s is larger than base image %s, and " "resize of base image failed", bs->filename, base->filename); goto error_restore_flags; } } bdrv_ref(base); mirror_start_job(bs, base, NULL, speed, 0, 0, on_error, on_error, false, cb, opaque, &local_err, &commit_active_job_driver, false, base); if (local_err) { error_propagate(errp, local_err); goto error_restore_flags; } return; error_restore_flags: /* ignore error and errp for bdrv_reopen, because we want to propagate * the original error */ bdrv_reopen(base, orig_base_flags, NULL); return; }