| /* |
| * Image mirroring |
| * |
| * Copyright Red Hat, Inc. 2012 |
| * |
| * Authors: |
| * Paolo Bonzini <pbonzini@redhat.com> |
| * |
| * 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" |
| |
| #define SLICE_TIME 100000000ULL /* ns */ |
| #define MAX_IN_FLIGHT 16 |
| #define MAX_IO_SECTORS ((1 << 20) >> BDRV_SECTOR_BITS) /* 1 Mb */ |
| #define DEFAULT_MIRROR_BUF_SIZE \ |
| (MAX_IN_FLIGHT * MAX_IO_SECTORS * BDRV_SECTOR_SIZE) |
| |
| /* 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; |
| BlockBackend *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; |
| BlockMirrorBackingMode backing_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; |
| BdrvDirtyBitmapIter *dbi; |
| uint8_t *buf; |
| QSIMPLEQ_HEAD(, MirrorBuffer) buf_free; |
| int buf_free_count; |
| |
| uint64_t last_pause_ns; |
| unsigned long *in_flight_bitmap; |
| int in_flight; |
| int64_t 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); |
| } |
| } |
| |
| 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; |
| } |
| blk_aio_pwritev(s->target, op->sector_num * BDRV_SECTOR_SIZE, &op->qiov, |
| 0, 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_sectors_to_clusters(blk_bs(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: The number of sectors copied after and including sector_num, |
| * excluding any sectors copied prior to sector_num due to alignment. |
| * This will be 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) |
| { |
| BlockBackend *source = s->common.blk; |
| int sectors_per_chunk, nb_chunks; |
| int ret; |
| MirrorOp *op; |
| int max_sectors; |
| |
| sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS; |
| max_sectors = sectors_per_chunk * s->max_iov; |
| |
| /* We can only handle as much as buf_size at a time. */ |
| nb_sectors = MIN(s->buf_size >> BDRV_SECTOR_BITS, nb_sectors); |
| nb_sectors = MIN(max_sectors, nb_sectors); |
| assert(nb_sectors); |
| ret = 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); |
| |
| blk_aio_preadv(source, sector_num * BDRV_SECTOR_SIZE, &op->qiov, 0, |
| 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) { |
| blk_aio_pdiscard(s->target, sector_num << BDRV_SECTOR_BITS, |
| op->nb_sectors << BDRV_SECTOR_BITS, |
| mirror_write_complete, op); |
| } else { |
| blk_aio_pwrite_zeroes(s->target, sector_num * BDRV_SECTOR_SIZE, |
| op->nb_sectors * BDRV_SECTOR_SIZE, |
| s->unmap ? BDRV_REQ_MAY_UNMAP : 0, |
| mirror_write_complete, op); |
| } |
| } |
| |
| static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) |
| { |
| BlockDriverState *source = blk_bs(s->common.blk); |
| 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; |
| bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target)); |
| int max_io_sectors = MAX((s->buf_size >> BDRV_SECTOR_BITS) / MAX_IN_FLIGHT, |
| MAX_IO_SECTORS); |
| |
| sector_num = bdrv_dirty_iter_next(s->dbi); |
| if (sector_num < 0) { |
| bdrv_set_dirty_iter(s->dbi, 0); |
| sector_num = bdrv_dirty_iter_next(s->dbi); |
| 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, sector_num, s->in_flight); |
| mirror_wait_for_io(s); |
| } |
| |
| block_job_pause_point(&s->common); |
| |
| /* 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 next_dirty; |
| 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; |
| } |
| |
| next_dirty = bdrv_dirty_iter_next(s->dbi); |
| if (next_dirty > next_sector || next_dirty < 0) { |
| /* The bitmap iterator's cache is stale, refresh it */ |
| bdrv_set_dirty_iter(s->dbi, next_sector); |
| next_dirty = bdrv_dirty_iter_next(s->dbi); |
| } |
| assert(next_dirty == 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, io_sectors_acct; |
| 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 = MIN(nb_chunks * sectors_per_chunk, max_io_sectors); |
| } else if (ret & BDRV_BLOCK_DATA) { |
| io_sectors = MIN(io_sectors, max_io_sectors); |
| } |
| |
| 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_sectors_to_clusters(blk_bs(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; |
| } |
| } |
| |
| while (s->in_flight >= MAX_IN_FLIGHT) { |
| trace_mirror_yield_in_flight(s, sector_num, s->in_flight); |
| mirror_wait_for_io(s); |
| } |
| |
| if (s->ret < 0) { |
| return 0; |
| } |
| |
| 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); |
| io_sectors_acct = io_sectors; |
| break; |
| case MIRROR_METHOD_ZERO: |
| case MIRROR_METHOD_DISCARD: |
| mirror_do_zero_or_discard(s, sector_num, io_sectors, |
| mirror_method == MIRROR_METHOD_DISCARD); |
| if (write_zeroes_ok) { |
| io_sectors_acct = 0; |
| } else { |
| io_sectors_acct = io_sectors; |
| } |
| break; |
| default: |
| abort(); |
| } |
| assert(io_sectors); |
| sector_num += io_sectors; |
| nb_chunks -= DIV_ROUND_UP(io_sectors, sectors_per_chunk); |
| if (s->common.speed) { |
| delay_ns = ratelimit_calculate_delay(&s->limit, io_sectors_acct); |
| } |
| } |
| 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; |
| } |
| } |
| |
| /* This is also used for the .pause callback. There is no matching |
| * mirror_resume() because mirror_run() will begin iterating again |
| * when the job is resumed. |
| */ |
| static void mirror_wait_for_all_io(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 = blk_bs(s->common.blk); |
| BlockDriverState *target_bs = blk_bs(s->target); |
| |
| /* 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 = src; |
| if (s->to_replace) { |
| to_replace = s->to_replace; |
| } |
| |
| if (bdrv_get_flags(target_bs) != bdrv_get_flags(to_replace)) { |
| bdrv_reopen(target_bs, bdrv_get_flags(to_replace), NULL); |
| } |
| |
| /* The mirror job has no requests in flight any more, but we need to |
| * drain potential other users of the BDS before changing the graph. */ |
| bdrv_drained_begin(target_bs); |
| bdrv_replace_in_backing_chain(to_replace, target_bs); |
| bdrv_drained_end(target_bs); |
| |
| /* We just changed the BDS the job BB refers to */ |
| blk_remove_bs(job->blk); |
| blk_insert_bs(job->blk, src); |
| } |
| 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); |
| blk_unref(s->target); |
| s->target = NULL; |
| block_job_completed(&s->common, data->ret); |
| g_free(data); |
| bdrv_drained_end(src); |
| bdrv_unref(src); |
| } |
| |
| static void mirror_throttle(MirrorBlockJob *s) |
| { |
| int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); |
| |
| if (now - s->last_pause_ns > SLICE_TIME) { |
| s->last_pause_ns = now; |
| block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, 0); |
| } else { |
| block_job_pause_point(&s->common); |
| } |
| } |
| |
| static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) |
| { |
| int64_t sector_num, end; |
| BlockDriverState *base = s->base; |
| BlockDriverState *bs = blk_bs(s->common.blk); |
| BlockDriverState *target_bs = blk_bs(s->target); |
| int ret, n; |
| |
| end = s->bdev_length / BDRV_SECTOR_SIZE; |
| |
| if (base == NULL && !bdrv_has_zero_init(target_bs)) { |
| if (!bdrv_can_write_zeroes_with_unmap(target_bs)) { |
| bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, end); |
| return 0; |
| } |
| |
| for (sector_num = 0; sector_num < end; ) { |
| int nb_sectors = MIN(end - sector_num, |
| QEMU_ALIGN_DOWN(INT_MAX, s->granularity) >> BDRV_SECTOR_BITS); |
| |
| mirror_throttle(s); |
| |
| if (block_job_is_cancelled(&s->common)) { |
| return 0; |
| } |
| |
| if (s->in_flight >= MAX_IN_FLIGHT) { |
| trace_mirror_yield(s, s->in_flight, s->buf_free_count, -1); |
| mirror_wait_for_io(s); |
| continue; |
| } |
| |
| mirror_do_zero_or_discard(s, sector_num, nb_sectors, false); |
| sector_num += nb_sectors; |
| } |
| |
| mirror_wait_for_all_io(s); |
| } |
| |
| /* First part, loop on the sectors and initialize the dirty bitmap. */ |
| 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); |
| |
| mirror_throttle(s); |
| |
| if (block_job_is_cancelled(&s->common)) { |
| return 0; |
| } |
| |
| ret = bdrv_is_allocated_above(bs, base, sector_num, nb_sectors, &n); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| assert(n > 0); |
| if (ret == 1) { |
| bdrv_set_dirty_bitmap(s->dirty_bitmap, sector_num, n); |
| } |
| sector_num += n; |
| } |
| return 0; |
| } |
| |
| static void coroutine_fn mirror_run(void *opaque) |
| { |
| MirrorBlockJob *s = opaque; |
| MirrorExitData *data; |
| BlockDriverState *bs = blk_bs(s->common.blk); |
| BlockDriverState *target_bs = blk_bs(s->target); |
| bool need_drain = true; |
| int64_t length; |
| BlockDriverInfo bdi; |
| char backing_filename[2]; /* we only need 2 characters because we are only |
| checking for a NULL string */ |
| int ret = 0; |
| 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(target_bs, backing_filename, |
| sizeof(backing_filename)); |
| if (!bdrv_get_info(target_bs, &bdi) && bdi.cluster_size) { |
| target_cluster_size = bdi.cluster_size; |
| } |
| if (backing_filename[0] && !target_bs->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(bs->bl.max_iov, target_bs->bl.max_iov); |
| |
| s->buf = qemu_try_blockalign(bs, s->buf_size); |
| if (s->buf == NULL) { |
| ret = -ENOMEM; |
| goto immediate_exit; |
| } |
| |
| mirror_free_init(s); |
| |
| s->last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); |
| if (!s->is_none_mode) { |
| ret = mirror_dirty_init(s); |
| if (ret < 0 || block_job_is_cancelled(&s->common)) { |
| goto immediate_exit; |
| } |
| } |
| |
| assert(!s->dbi); |
| s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap, 0); |
| for (;;) { |
| uint64_t delay_ns = 0; |
| int64_t cnt, delta; |
| bool should_complete; |
| |
| if (s->ret < 0) { |
| ret = s->ret; |
| goto immediate_exit; |
| } |
| |
| block_job_pause_point(&s->common); |
| |
| 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. |
| */ |
| delta = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - s->last_pause_ns; |
| if (delta < 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 = blk_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, so pause it now. Before deciding |
| * whether to switch to target check one last time if I/O has |
| * come in the meanwhile, and if not flush the data to disk. |
| */ |
| trace_mirror_before_drain(s, cnt); |
| |
| bdrv_drained_begin(bs); |
| cnt = bdrv_get_dirty_count(s->dirty_bitmap); |
| if (cnt > 0) { |
| bdrv_drained_end(bs); |
| continue; |
| } |
| |
| /* The two disks are in sync. Exit and report successful |
| * completion. |
| */ |
| assert(QLIST_EMPTY(&bs->tracked_requests)); |
| s->common.cancelled = false; |
| need_drain = false; |
| break; |
| } |
| |
| 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); |
| } |
| s->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))); |
| assert(need_drain); |
| mirror_wait_for_all_io(s); |
| } |
| |
| assert(s->in_flight == 0); |
| qemu_vfree(s->buf); |
| g_free(s->cow_bitmap); |
| g_free(s->in_flight_bitmap); |
| bdrv_dirty_iter_free(s->dbi); |
| bdrv_release_dirty_bitmap(bs, s->dirty_bitmap); |
| |
| data = g_malloc(sizeof(*data)); |
| data->ret = ret; |
| |
| if (need_drain) { |
| bdrv_drained_begin(bs); |
| } |
| 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); |
| BlockDriverState *src, *target; |
| |
| src = blk_bs(job->blk); |
| target = blk_bs(s->target); |
| |
| if (!s->synced) { |
| error_setg(errp, "The active block job '%s' cannot be completed", |
| job->id); |
| return; |
| } |
| |
| if (s->backing_mode == MIRROR_OPEN_BACKING_CHAIN) { |
| int ret; |
| |
| assert(!target->backing); |
| ret = bdrv_open_backing_file(target, NULL, "backing", errp); |
| if (ret < 0) { |
| return; |
| } |
| } |
| |
| /* block all operations on to_replace bs */ |
| 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); |
| } |
| |
| if (s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) { |
| BlockDriverState *backing = s->is_none_mode ? src : s->base; |
| if (backing_bs(target) != backing) { |
| bdrv_set_backing_hd(target, backing); |
| } |
| } |
| |
| s->should_complete = true; |
| block_job_enter(&s->common); |
| } |
| |
| static void mirror_pause(BlockJob *job) |
| { |
| MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); |
| |
| mirror_wait_for_all_io(s); |
| } |
| |
| static void mirror_attached_aio_context(BlockJob *job, AioContext *new_context) |
| { |
| MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); |
| |
| blk_set_aio_context(s->target, new_context); |
| } |
| |
| static void mirror_drain(BlockJob *job) |
| { |
| MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); |
| |
| /* Need to keep a reference in case blk_drain triggers execution |
| * of mirror_complete... |
| */ |
| if (s->target) { |
| BlockBackend *target = s->target; |
| blk_ref(target); |
| blk_drain(target); |
| blk_unref(target); |
| } |
| } |
| |
| static const BlockJobDriver mirror_job_driver = { |
| .instance_size = sizeof(MirrorBlockJob), |
| .job_type = BLOCK_JOB_TYPE_MIRROR, |
| .set_speed = mirror_set_speed, |
| .complete = mirror_complete, |
| .pause = mirror_pause, |
| .attached_aio_context = mirror_attached_aio_context, |
| .drain = mirror_drain, |
| }; |
| |
| 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, |
| .pause = mirror_pause, |
| .attached_aio_context = mirror_attached_aio_context, |
| .drain = mirror_drain, |
| }; |
| |
| static void mirror_start_job(const char *job_id, BlockDriverState *bs, |
| int creation_flags, BlockDriverState *target, |
| const char *replaces, int64_t speed, |
| uint32_t granularity, int64_t buf_size, |
| BlockMirrorBackingMode backing_mode, |
| 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, |
| bool auto_complete) |
| { |
| MirrorBlockJob *s; |
| |
| 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; |
| } |
| |
| s = block_job_create(job_id, driver, bs, speed, creation_flags, |
| cb, opaque, errp); |
| if (!s) { |
| return; |
| } |
| |
| s->target = blk_new(); |
| blk_insert_bs(s->target, target); |
| |
| s->replaces = g_strdup(replaces); |
| s->on_source_error = on_source_error; |
| s->on_target_error = on_target_error; |
| s->is_none_mode = is_none_mode; |
| s->backing_mode = backing_mode; |
| s->base = base; |
| s->granularity = granularity; |
| s->buf_size = ROUND_UP(buf_size, granularity); |
| s->unmap = unmap; |
| if (auto_complete) { |
| s->should_complete = true; |
| } |
| |
| s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp); |
| if (!s->dirty_bitmap) { |
| g_free(s->replaces); |
| blk_unref(s->target); |
| block_job_unref(&s->common); |
| return; |
| } |
| |
| block_job_add_bdrv(&s->common, target); |
| /* In commit_active_start() all intermediate nodes disappear, so |
| * any jobs in them must be blocked */ |
| if (bdrv_chain_contains(bs, target)) { |
| BlockDriverState *iter; |
| for (iter = backing_bs(bs); iter != target; iter = backing_bs(iter)) { |
| block_job_add_bdrv(&s->common, iter); |
| } |
| } |
| |
| s->common.co = qemu_coroutine_create(mirror_run, s); |
| trace_mirror_start(bs, s, s->common.co, opaque); |
| qemu_coroutine_enter(s->common.co); |
| } |
| |
| void mirror_start(const char *job_id, BlockDriverState *bs, |
| BlockDriverState *target, const char *replaces, |
| int64_t speed, uint32_t granularity, int64_t buf_size, |
| MirrorSyncMode mode, BlockMirrorBackingMode backing_mode, |
| BlockdevOnError on_source_error, |
| BlockdevOnError on_target_error, |
| bool unmap, 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(job_id, bs, BLOCK_JOB_DEFAULT, target, replaces, |
| speed, granularity, buf_size, backing_mode, |
| on_source_error, on_target_error, unmap, NULL, NULL, errp, |
| &mirror_job_driver, is_none_mode, base, false); |
| } |
| |
| void commit_active_start(const char *job_id, BlockDriverState *bs, |
| BlockDriverState *base, int creation_flags, |
| int64_t speed, BlockdevOnError on_error, |
| BlockCompletionFunc *cb, void *opaque, Error **errp, |
| bool auto_complete) |
| { |
| 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; |
| } |
| } |
| |
| mirror_start_job(job_id, bs, creation_flags, base, NULL, speed, 0, 0, |
| MIRROR_LEAVE_BACKING_CHAIN, |
| on_error, on_error, true, cb, opaque, &local_err, |
| &commit_active_job_driver, false, base, auto_complete); |
| 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; |
| } |