| /* |
| * 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 "qemu/cutils.h" |
| #include "qemu/coroutine.h" |
| #include "qemu/range.h" |
| #include "trace.h" |
| #include "block/blockjob_int.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 MAX_IN_FLIGHT 16 |
| #define MAX_IO_BYTES (1 << 20) /* 1 Mb */ |
| #define DEFAULT_MIRROR_BUF_SIZE (MAX_IN_FLIGHT * MAX_IO_BYTES) |
| |
| /* 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 MirrorOp MirrorOp; |
| |
| typedef struct MirrorBlockJob { |
| BlockJob common; |
| BlockBackend *target; |
| BlockDriverState *mirror_top_bs; |
| BlockDriverState *base; |
| BlockDriverState *base_overlay; |
| |
| /* 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; |
| /* Whether the target image requires explicit zero-initialization */ |
| bool zero_target; |
| MirrorCopyMode copy_mode; |
| BlockdevOnError on_source_error, on_target_error; |
| /* Set when the target is synced (dirty bitmap is clean, nothing |
| * in flight) and the job is running in active mode */ |
| bool actively_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 bytes_in_flight; |
| QTAILQ_HEAD(, MirrorOp) ops_in_flight; |
| int ret; |
| bool unmap; |
| int target_cluster_size; |
| int max_iov; |
| bool initial_zeroing_ongoing; |
| int in_active_write_counter; |
| bool prepared; |
| bool in_drain; |
| } MirrorBlockJob; |
| |
| typedef struct MirrorBDSOpaque { |
| MirrorBlockJob *job; |
| bool stop; |
| bool is_commit; |
| } MirrorBDSOpaque; |
| |
| struct MirrorOp { |
| MirrorBlockJob *s; |
| QEMUIOVector qiov; |
| int64_t offset; |
| uint64_t bytes; |
| |
| /* The pointee is set by mirror_co_read(), mirror_co_zero(), and |
| * mirror_co_discard() before yielding for the first time */ |
| int64_t *bytes_handled; |
| |
| bool is_pseudo_op; |
| bool is_active_write; |
| bool is_in_flight; |
| CoQueue waiting_requests; |
| Coroutine *co; |
| MirrorOp *waiting_for_op; |
| |
| QTAILQ_ENTRY(MirrorOp) next; |
| }; |
| |
| typedef enum MirrorMethod { |
| MIRROR_METHOD_COPY, |
| MIRROR_METHOD_ZERO, |
| MIRROR_METHOD_DISCARD, |
| } MirrorMethod; |
| |
| static BlockErrorAction mirror_error_action(MirrorBlockJob *s, bool read, |
| int error) |
| { |
| s->actively_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 coroutine_fn mirror_wait_on_conflicts(MirrorOp *self, |
| MirrorBlockJob *s, |
| uint64_t offset, |
| uint64_t bytes) |
| { |
| uint64_t self_start_chunk = offset / s->granularity; |
| uint64_t self_end_chunk = DIV_ROUND_UP(offset + bytes, s->granularity); |
| uint64_t self_nb_chunks = self_end_chunk - self_start_chunk; |
| |
| while (find_next_bit(s->in_flight_bitmap, self_end_chunk, |
| self_start_chunk) < self_end_chunk && |
| s->ret >= 0) |
| { |
| MirrorOp *op; |
| |
| QTAILQ_FOREACH(op, &s->ops_in_flight, next) { |
| uint64_t op_start_chunk = op->offset / s->granularity; |
| uint64_t op_nb_chunks = DIV_ROUND_UP(op->offset + op->bytes, |
| s->granularity) - |
| op_start_chunk; |
| |
| if (op == self) { |
| continue; |
| } |
| |
| if (ranges_overlap(self_start_chunk, self_nb_chunks, |
| op_start_chunk, op_nb_chunks)) |
| { |
| if (self) { |
| /* |
| * If the operation is already (indirectly) waiting for us, |
| * or will wait for us as soon as it wakes up, then just go |
| * on (instead of producing a deadlock in the former case). |
| */ |
| if (op->waiting_for_op) { |
| continue; |
| } |
| |
| self->waiting_for_op = op; |
| } |
| |
| qemu_co_queue_wait(&op->waiting_requests, NULL); |
| |
| if (self) { |
| self->waiting_for_op = NULL; |
| } |
| |
| break; |
| } |
| } |
| } |
| } |
| |
| static void coroutine_fn mirror_iteration_done(MirrorOp *op, int ret) |
| { |
| MirrorBlockJob *s = op->s; |
| struct iovec *iov; |
| int64_t chunk_num; |
| int i, nb_chunks; |
| |
| trace_mirror_iteration_done(s, op->offset, op->bytes, ret); |
| |
| s->in_flight--; |
| s->bytes_in_flight -= op->bytes; |
| 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++; |
| } |
| |
| chunk_num = op->offset / s->granularity; |
| nb_chunks = DIV_ROUND_UP(op->bytes, s->granularity); |
| |
| bitmap_clear(s->in_flight_bitmap, chunk_num, nb_chunks); |
| QTAILQ_REMOVE(&s->ops_in_flight, op, next); |
| if (ret >= 0) { |
| if (s->cow_bitmap) { |
| bitmap_set(s->cow_bitmap, chunk_num, nb_chunks); |
| } |
| if (!s->initial_zeroing_ongoing) { |
| job_progress_update(&s->common.job, op->bytes); |
| } |
| } |
| qemu_iovec_destroy(&op->qiov); |
| |
| qemu_co_queue_restart_all(&op->waiting_requests); |
| g_free(op); |
| } |
| |
| static void coroutine_fn mirror_write_complete(MirrorOp *op, int ret) |
| { |
| MirrorBlockJob *s = op->s; |
| |
| if (ret < 0) { |
| BlockErrorAction action; |
| |
| bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset, op->bytes); |
| 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 coroutine_fn mirror_read_complete(MirrorOp *op, int ret) |
| { |
| MirrorBlockJob *s = op->s; |
| |
| if (ret < 0) { |
| BlockErrorAction action; |
| |
| bdrv_set_dirty_bitmap(s->dirty_bitmap, op->offset, op->bytes); |
| 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; |
| } |
| |
| ret = blk_co_pwritev(s->target, op->offset, op->qiov.size, &op->qiov, 0); |
| mirror_write_complete(op, ret); |
| } |
| |
| /* Clip bytes relative to offset to not exceed end-of-file */ |
| static inline int64_t mirror_clip_bytes(MirrorBlockJob *s, |
| int64_t offset, |
| int64_t bytes) |
| { |
| return MIN(bytes, s->bdev_length - offset); |
| } |
| |
| /* Round offset and/or bytes to target cluster if COW is needed, and |
| * return the offset of the adjusted tail against original. */ |
| static int mirror_cow_align(MirrorBlockJob *s, int64_t *offset, |
| uint64_t *bytes) |
| { |
| bool need_cow; |
| int ret = 0; |
| int64_t align_offset = *offset; |
| int64_t align_bytes = *bytes; |
| int max_bytes = s->granularity * s->max_iov; |
| |
| need_cow = !test_bit(*offset / s->granularity, s->cow_bitmap); |
| need_cow |= !test_bit((*offset + *bytes - 1) / s->granularity, |
| s->cow_bitmap); |
| if (need_cow) { |
| bdrv_round_to_clusters(blk_bs(s->target), *offset, *bytes, |
| &align_offset, &align_bytes); |
| } |
| |
| if (align_bytes > max_bytes) { |
| align_bytes = max_bytes; |
| if (need_cow) { |
| align_bytes = QEMU_ALIGN_DOWN(align_bytes, s->target_cluster_size); |
| } |
| } |
| /* Clipping may result in align_bytes unaligned to chunk boundary, but |
| * that doesn't matter because it's already the end of source image. */ |
| align_bytes = mirror_clip_bytes(s, align_offset, align_bytes); |
| |
| ret = align_offset + align_bytes - (*offset + *bytes); |
| *offset = align_offset; |
| *bytes = align_bytes; |
| assert(ret >= 0); |
| return ret; |
| } |
| |
| static inline void coroutine_fn |
| mirror_wait_for_any_operation(MirrorBlockJob *s, bool active) |
| { |
| MirrorOp *op; |
| |
| QTAILQ_FOREACH(op, &s->ops_in_flight, next) { |
| /* Do not wait on pseudo ops, because it may in turn wait on |
| * some other operation to start, which may in fact be the |
| * caller of this function. Since there is only one pseudo op |
| * at any given time, we will always find some real operation |
| * to wait on. */ |
| if (!op->is_pseudo_op && op->is_in_flight && |
| op->is_active_write == active) |
| { |
| qemu_co_queue_wait(&op->waiting_requests, NULL); |
| return; |
| } |
| } |
| abort(); |
| } |
| |
| static inline void coroutine_fn |
| mirror_wait_for_free_in_flight_slot(MirrorBlockJob *s) |
| { |
| /* Only non-active operations use up in-flight slots */ |
| mirror_wait_for_any_operation(s, false); |
| } |
| |
| /* Perform a mirror copy operation. |
| * |
| * *op->bytes_handled is set to the number of bytes copied after and |
| * including offset, excluding any bytes copied prior to offset due |
| * to alignment. This will be op->bytes if no alignment is necessary, |
| * or (new_end - op->offset) if the tail is rounded up or down due to |
| * alignment or buffer limit. |
| */ |
| static void coroutine_fn mirror_co_read(void *opaque) |
| { |
| MirrorOp *op = opaque; |
| MirrorBlockJob *s = op->s; |
| int nb_chunks; |
| uint64_t ret; |
| uint64_t max_bytes; |
| |
| max_bytes = s->granularity * s->max_iov; |
| |
| /* We can only handle as much as buf_size at a time. */ |
| op->bytes = MIN(s->buf_size, MIN(max_bytes, op->bytes)); |
| assert(op->bytes); |
| assert(op->bytes < BDRV_REQUEST_MAX_BYTES); |
| *op->bytes_handled = op->bytes; |
| |
| if (s->cow_bitmap) { |
| *op->bytes_handled += mirror_cow_align(s, &op->offset, &op->bytes); |
| } |
| /* Cannot exceed BDRV_REQUEST_MAX_BYTES + INT_MAX */ |
| assert(*op->bytes_handled <= UINT_MAX); |
| assert(op->bytes <= s->buf_size); |
| /* The offset is granularity-aligned because: |
| * 1) Caller passes in aligned values; |
| * 2) mirror_cow_align is used only when target cluster is larger. */ |
| assert(QEMU_IS_ALIGNED(op->offset, s->granularity)); |
| /* The range is sector-aligned, since bdrv_getlength() rounds up. */ |
| assert(QEMU_IS_ALIGNED(op->bytes, BDRV_SECTOR_SIZE)); |
| nb_chunks = DIV_ROUND_UP(op->bytes, s->granularity); |
| |
| while (s->buf_free_count < nb_chunks) { |
| trace_mirror_yield_in_flight(s, op->offset, s->in_flight); |
| mirror_wait_for_free_in_flight_slot(s); |
| } |
| |
| /* 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 = op->bytes - 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->bytes_in_flight += op->bytes; |
| op->is_in_flight = true; |
| trace_mirror_one_iteration(s, op->offset, op->bytes); |
| |
| ret = bdrv_co_preadv(s->mirror_top_bs->backing, op->offset, op->bytes, |
| &op->qiov, 0); |
| mirror_read_complete(op, ret); |
| } |
| |
| static void coroutine_fn mirror_co_zero(void *opaque) |
| { |
| MirrorOp *op = opaque; |
| int ret; |
| |
| op->s->in_flight++; |
| op->s->bytes_in_flight += op->bytes; |
| *op->bytes_handled = op->bytes; |
| op->is_in_flight = true; |
| |
| ret = blk_co_pwrite_zeroes(op->s->target, op->offset, op->bytes, |
| op->s->unmap ? BDRV_REQ_MAY_UNMAP : 0); |
| mirror_write_complete(op, ret); |
| } |
| |
| static void coroutine_fn mirror_co_discard(void *opaque) |
| { |
| MirrorOp *op = opaque; |
| int ret; |
| |
| op->s->in_flight++; |
| op->s->bytes_in_flight += op->bytes; |
| *op->bytes_handled = op->bytes; |
| op->is_in_flight = true; |
| |
| ret = blk_co_pdiscard(op->s->target, op->offset, op->bytes); |
| mirror_write_complete(op, ret); |
| } |
| |
| static unsigned mirror_perform(MirrorBlockJob *s, int64_t offset, |
| unsigned bytes, MirrorMethod mirror_method) |
| { |
| MirrorOp *op; |
| Coroutine *co; |
| int64_t bytes_handled = -1; |
| |
| op = g_new(MirrorOp, 1); |
| *op = (MirrorOp){ |
| .s = s, |
| .offset = offset, |
| .bytes = bytes, |
| .bytes_handled = &bytes_handled, |
| }; |
| qemu_co_queue_init(&op->waiting_requests); |
| |
| switch (mirror_method) { |
| case MIRROR_METHOD_COPY: |
| co = qemu_coroutine_create(mirror_co_read, op); |
| break; |
| case MIRROR_METHOD_ZERO: |
| co = qemu_coroutine_create(mirror_co_zero, op); |
| break; |
| case MIRROR_METHOD_DISCARD: |
| co = qemu_coroutine_create(mirror_co_discard, op); |
| break; |
| default: |
| abort(); |
| } |
| op->co = co; |
| |
| QTAILQ_INSERT_TAIL(&s->ops_in_flight, op, next); |
| qemu_coroutine_enter(co); |
| /* At this point, ownership of op has been moved to the coroutine |
| * and the object may already be freed */ |
| |
| /* Assert that this value has been set */ |
| assert(bytes_handled >= 0); |
| |
| /* Same assertion as in mirror_co_read() (and for mirror_co_read() |
| * and mirror_co_discard(), bytes_handled == op->bytes, which |
| * is the @bytes parameter given to this function) */ |
| assert(bytes_handled <= UINT_MAX); |
| return bytes_handled; |
| } |
| |
| static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) |
| { |
| BlockDriverState *source = s->mirror_top_bs->backing->bs; |
| MirrorOp *pseudo_op; |
| int64_t offset; |
| uint64_t delay_ns = 0, ret = 0; |
| /* At least the first dirty chunk is mirrored in one iteration. */ |
| int nb_chunks = 1; |
| bool write_zeroes_ok = bdrv_can_write_zeroes_with_unmap(blk_bs(s->target)); |
| int max_io_bytes = MAX(s->buf_size / MAX_IN_FLIGHT, MAX_IO_BYTES); |
| |
| bdrv_dirty_bitmap_lock(s->dirty_bitmap); |
| offset = bdrv_dirty_iter_next(s->dbi); |
| if (offset < 0) { |
| bdrv_set_dirty_iter(s->dbi, 0); |
| offset = bdrv_dirty_iter_next(s->dbi); |
| trace_mirror_restart_iter(s, bdrv_get_dirty_count(s->dirty_bitmap)); |
| assert(offset >= 0); |
| } |
| bdrv_dirty_bitmap_unlock(s->dirty_bitmap); |
| |
| mirror_wait_on_conflicts(NULL, s, offset, 1); |
| |
| job_pause_point(&s->common.job); |
| |
| /* Find the number of consective dirty chunks following the first dirty |
| * one, and wait for in flight requests in them. */ |
| bdrv_dirty_bitmap_lock(s->dirty_bitmap); |
| while (nb_chunks * s->granularity < s->buf_size) { |
| int64_t next_dirty; |
| int64_t next_offset = offset + nb_chunks * s->granularity; |
| int64_t next_chunk = next_offset / s->granularity; |
| if (next_offset >= s->bdev_length || |
| !bdrv_dirty_bitmap_get_locked(s->dirty_bitmap, next_offset)) { |
| break; |
| } |
| if (test_bit(next_chunk, s->in_flight_bitmap)) { |
| break; |
| } |
| |
| next_dirty = bdrv_dirty_iter_next(s->dbi); |
| if (next_dirty > next_offset || next_dirty < 0) { |
| /* The bitmap iterator's cache is stale, refresh it */ |
| bdrv_set_dirty_iter(s->dbi, next_offset); |
| next_dirty = bdrv_dirty_iter_next(s->dbi); |
| } |
| assert(next_dirty == next_offset); |
| nb_chunks++; |
| } |
| |
| /* Clear dirty bits before querying the block status, because |
| * calling bdrv_block_status_above could yield - if some blocks are |
| * marked dirty in this window, we need to know. |
| */ |
| bdrv_reset_dirty_bitmap_locked(s->dirty_bitmap, offset, |
| nb_chunks * s->granularity); |
| bdrv_dirty_bitmap_unlock(s->dirty_bitmap); |
| |
| /* Before claiming an area in the in-flight bitmap, we have to |
| * create a MirrorOp for it so that conflicting requests can wait |
| * for it. mirror_perform() will create the real MirrorOps later, |
| * for now we just create a pseudo operation that will wake up all |
| * conflicting requests once all real operations have been |
| * launched. */ |
| pseudo_op = g_new(MirrorOp, 1); |
| *pseudo_op = (MirrorOp){ |
| .offset = offset, |
| .bytes = nb_chunks * s->granularity, |
| .is_pseudo_op = true, |
| }; |
| qemu_co_queue_init(&pseudo_op->waiting_requests); |
| QTAILQ_INSERT_TAIL(&s->ops_in_flight, pseudo_op, next); |
| |
| bitmap_set(s->in_flight_bitmap, offset / s->granularity, nb_chunks); |
| while (nb_chunks > 0 && offset < s->bdev_length) { |
| int ret; |
| int64_t io_bytes; |
| int64_t io_bytes_acct; |
| MirrorMethod mirror_method = MIRROR_METHOD_COPY; |
| |
| assert(!(offset % s->granularity)); |
| ret = bdrv_block_status_above(source, NULL, offset, |
| nb_chunks * s->granularity, |
| &io_bytes, NULL, NULL); |
| if (ret < 0) { |
| io_bytes = MIN(nb_chunks * s->granularity, max_io_bytes); |
| } else if (ret & BDRV_BLOCK_DATA) { |
| io_bytes = MIN(io_bytes, max_io_bytes); |
| } |
| |
| io_bytes -= io_bytes % s->granularity; |
| if (io_bytes < s->granularity) { |
| io_bytes = s->granularity; |
| } else if (ret >= 0 && !(ret & BDRV_BLOCK_DATA)) { |
| int64_t target_offset; |
| int64_t target_bytes; |
| bdrv_round_to_clusters(blk_bs(s->target), offset, io_bytes, |
| &target_offset, &target_bytes); |
| if (target_offset == offset && |
| target_bytes == io_bytes) { |
| 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, offset, s->in_flight); |
| mirror_wait_for_free_in_flight_slot(s); |
| } |
| |
| if (s->ret < 0) { |
| ret = 0; |
| goto fail; |
| } |
| |
| io_bytes = mirror_clip_bytes(s, offset, io_bytes); |
| io_bytes = mirror_perform(s, offset, io_bytes, mirror_method); |
| if (mirror_method != MIRROR_METHOD_COPY && write_zeroes_ok) { |
| io_bytes_acct = 0; |
| } else { |
| io_bytes_acct = io_bytes; |
| } |
| assert(io_bytes); |
| offset += io_bytes; |
| nb_chunks -= DIV_ROUND_UP(io_bytes, s->granularity); |
| delay_ns = block_job_ratelimit_get_delay(&s->common, io_bytes_acct); |
| } |
| |
| ret = delay_ns; |
| fail: |
| QTAILQ_REMOVE(&s->ops_in_flight, pseudo_op, next); |
| qemu_co_queue_restart_all(&pseudo_op->waiting_requests); |
| g_free(pseudo_op); |
| |
| 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; |
| } |
| } |
| |
| /* 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 coroutine_fn mirror_wait_for_all_io(MirrorBlockJob *s) |
| { |
| while (s->in_flight > 0) { |
| mirror_wait_for_free_in_flight_slot(s); |
| } |
| } |
| |
| /** |
| * mirror_exit_common: handle both abort() and prepare() cases. |
| * for .prepare, returns 0 on success and -errno on failure. |
| * for .abort cases, denoted by abort = true, MUST return 0. |
| */ |
| static int mirror_exit_common(Job *job) |
| { |
| MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job); |
| BlockJob *bjob = &s->common; |
| MirrorBDSOpaque *bs_opaque; |
| AioContext *replace_aio_context = NULL; |
| BlockDriverState *src; |
| BlockDriverState *target_bs; |
| BlockDriverState *mirror_top_bs; |
| Error *local_err = NULL; |
| bool abort = job->ret < 0; |
| int ret = 0; |
| |
| if (s->prepared) { |
| return 0; |
| } |
| s->prepared = true; |
| |
| mirror_top_bs = s->mirror_top_bs; |
| bs_opaque = mirror_top_bs->opaque; |
| src = mirror_top_bs->backing->bs; |
| target_bs = blk_bs(s->target); |
| |
| if (bdrv_chain_contains(src, target_bs)) { |
| bdrv_unfreeze_backing_chain(mirror_top_bs, target_bs); |
| } |
| |
| bdrv_release_dirty_bitmap(s->dirty_bitmap); |
| |
| /* Make sure that the source BDS doesn't go away during bdrv_replace_node, |
| * before we can call bdrv_drained_end */ |
| bdrv_ref(src); |
| bdrv_ref(mirror_top_bs); |
| bdrv_ref(target_bs); |
| |
| /* |
| * Remove target parent that still uses BLK_PERM_WRITE/RESIZE before |
| * inserting target_bs at s->to_replace, where we might not be able to get |
| * these permissions. |
| */ |
| blk_unref(s->target); |
| s->target = NULL; |
| |
| /* We don't access the source any more. Dropping any WRITE/RESIZE is |
| * required before it could become a backing file of target_bs. Not having |
| * these permissions any more means that we can't allow any new requests on |
| * mirror_top_bs from now on, so keep it drained. */ |
| bdrv_drained_begin(mirror_top_bs); |
| bs_opaque->stop = true; |
| bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing, |
| &error_abort); |
| if (!abort && s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) { |
| BlockDriverState *backing = s->is_none_mode ? src : s->base; |
| BlockDriverState *unfiltered_target = bdrv_skip_filters(target_bs); |
| |
| if (bdrv_cow_bs(unfiltered_target) != backing) { |
| bdrv_set_backing_hd(unfiltered_target, backing, &local_err); |
| if (local_err) { |
| error_report_err(local_err); |
| local_err = NULL; |
| ret = -EPERM; |
| } |
| } |
| } else if (!abort && s->backing_mode == MIRROR_OPEN_BACKING_CHAIN) { |
| assert(!bdrv_backing_chain_next(target_bs)); |
| ret = bdrv_open_backing_file(bdrv_skip_filters(target_bs), NULL, |
| "backing", &local_err); |
| if (ret < 0) { |
| error_report_err(local_err); |
| local_err = NULL; |
| } |
| } |
| |
| if (s->to_replace) { |
| replace_aio_context = bdrv_get_aio_context(s->to_replace); |
| aio_context_acquire(replace_aio_context); |
| } |
| |
| if (s->should_complete && !abort) { |
| BlockDriverState *to_replace = s->to_replace ?: src; |
| bool ro = bdrv_is_read_only(to_replace); |
| |
| if (ro != bdrv_is_read_only(target_bs)) { |
| bdrv_reopen_set_read_only(target_bs, ro, 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. */ |
| assert(s->in_drain); |
| bdrv_drained_begin(target_bs); |
| /* |
| * Cannot use check_to_replace_node() here, because that would |
| * check for an op blocker on @to_replace, and we have our own |
| * there. |
| */ |
| if (bdrv_recurse_can_replace(src, to_replace)) { |
| bdrv_replace_node(to_replace, target_bs, &local_err); |
| } else { |
| error_setg(&local_err, "Can no longer replace '%s' by '%s', " |
| "because it can no longer be guaranteed that doing so " |
| "would not lead to an abrupt change of visible data", |
| to_replace->node_name, target_bs->node_name); |
| } |
| bdrv_drained_end(target_bs); |
| if (local_err) { |
| error_report_err(local_err); |
| ret = -EPERM; |
| } |
| } |
| 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_unref(target_bs); |
| |
| /* |
| * Remove the mirror filter driver from the graph. Before this, get rid of |
| * the blockers on the intermediate nodes so that the resulting state is |
| * valid. |
| */ |
| block_job_remove_all_bdrv(bjob); |
| bdrv_replace_node(mirror_top_bs, mirror_top_bs->backing->bs, &error_abort); |
| |
| bs_opaque->job = NULL; |
| |
| bdrv_drained_end(src); |
| bdrv_drained_end(mirror_top_bs); |
| s->in_drain = false; |
| bdrv_unref(mirror_top_bs); |
| bdrv_unref(src); |
| |
| return ret; |
| } |
| |
| static int mirror_prepare(Job *job) |
| { |
| return mirror_exit_common(job); |
| } |
| |
| static void mirror_abort(Job *job) |
| { |
| int ret = mirror_exit_common(job); |
| assert(ret == 0); |
| } |
| |
| static void coroutine_fn mirror_throttle(MirrorBlockJob *s) |
| { |
| int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); |
| |
| if (now - s->last_pause_ns > BLOCK_JOB_SLICE_TIME) { |
| s->last_pause_ns = now; |
| job_sleep_ns(&s->common.job, 0); |
| } else { |
| job_pause_point(&s->common.job); |
| } |
| } |
| |
| static int coroutine_fn mirror_dirty_init(MirrorBlockJob *s) |
| { |
| int64_t offset; |
| BlockDriverState *bs = s->mirror_top_bs->backing->bs; |
| BlockDriverState *target_bs = blk_bs(s->target); |
| int ret; |
| int64_t count; |
| |
| if (s->zero_target) { |
| if (!bdrv_can_write_zeroes_with_unmap(target_bs)) { |
| bdrv_set_dirty_bitmap(s->dirty_bitmap, 0, s->bdev_length); |
| return 0; |
| } |
| |
| s->initial_zeroing_ongoing = true; |
| for (offset = 0; offset < s->bdev_length; ) { |
| int bytes = MIN(s->bdev_length - offset, |
| QEMU_ALIGN_DOWN(INT_MAX, s->granularity)); |
| |
| mirror_throttle(s); |
| |
| if (job_is_cancelled(&s->common.job)) { |
| s->initial_zeroing_ongoing = false; |
| return 0; |
| } |
| |
| if (s->in_flight >= MAX_IN_FLIGHT) { |
| trace_mirror_yield(s, UINT64_MAX, s->buf_free_count, |
| s->in_flight); |
| mirror_wait_for_free_in_flight_slot(s); |
| continue; |
| } |
| |
| mirror_perform(s, offset, bytes, MIRROR_METHOD_ZERO); |
| offset += bytes; |
| } |
| |
| mirror_wait_for_all_io(s); |
| s->initial_zeroing_ongoing = false; |
| } |
| |
| /* First part, loop on the sectors and initialize the dirty bitmap. */ |
| for (offset = 0; offset < s->bdev_length; ) { |
| /* Just to make sure we are not exceeding int limit. */ |
| int bytes = MIN(s->bdev_length - offset, |
| QEMU_ALIGN_DOWN(INT_MAX, s->granularity)); |
| |
| mirror_throttle(s); |
| |
| if (job_is_cancelled(&s->common.job)) { |
| return 0; |
| } |
| |
| ret = bdrv_is_allocated_above(bs, s->base_overlay, true, offset, bytes, |
| &count); |
| if (ret < 0) { |
| return ret; |
| } |
| |
| assert(count); |
| if (ret > 0) { |
| bdrv_set_dirty_bitmap(s->dirty_bitmap, offset, count); |
| } |
| offset += count; |
| } |
| return 0; |
| } |
| |
| /* Called when going out of the streaming phase to flush the bulk of the |
| * data to the medium, or just before completing. |
| */ |
| static int mirror_flush(MirrorBlockJob *s) |
| { |
| int ret = blk_flush(s->target); |
| if (ret < 0) { |
| if (mirror_error_action(s, false, -ret) == BLOCK_ERROR_ACTION_REPORT) { |
| s->ret = ret; |
| } |
| } |
| return ret; |
| } |
| |
| static int coroutine_fn mirror_run(Job *job, Error **errp) |
| { |
| MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job); |
| BlockDriverState *bs = s->mirror_top_bs->backing->bs; |
| BlockDriverState *target_bs = blk_bs(s->target); |
| bool need_drain = true; |
| int64_t length; |
| int64_t target_length; |
| BlockDriverInfo bdi; |
| char backing_filename[2]; /* we only need 2 characters because we are only |
| checking for a NULL string */ |
| int ret = 0; |
| |
| if (job_is_cancelled(&s->common.job)) { |
| goto immediate_exit; |
| } |
| |
| s->bdev_length = bdrv_getlength(bs); |
| if (s->bdev_length < 0) { |
| ret = s->bdev_length; |
| goto immediate_exit; |
| } |
| |
| target_length = blk_getlength(s->target); |
| if (target_length < 0) { |
| ret = target_length; |
| goto immediate_exit; |
| } |
| |
| /* Active commit must resize the base image if its size differs from the |
| * active layer. */ |
| if (s->base == blk_bs(s->target)) { |
| if (s->bdev_length > target_length) { |
| ret = blk_truncate(s->target, s->bdev_length, false, |
| PREALLOC_MODE_OFF, 0, NULL); |
| if (ret < 0) { |
| goto immediate_exit; |
| } |
| } |
| } else if (s->bdev_length != target_length) { |
| error_setg(errp, "Source and target image have different sizes"); |
| ret = -EINVAL; |
| goto immediate_exit; |
| } |
| |
| if (s->bdev_length == 0) { |
| /* Transition to the READY state and wait for complete. */ |
| job_transition_to_ready(&s->common.job); |
| s->actively_synced = true; |
| while (!job_cancel_requested(&s->common.job) && !s->should_complete) { |
| job_yield(&s->common.job); |
| } |
| 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) { |
| s->target_cluster_size = bdi.cluster_size; |
| } else { |
| s->target_cluster_size = BDRV_SECTOR_SIZE; |
| } |
| if (backing_filename[0] && !bdrv_backing_chain_next(target_bs) && |
| s->granularity < s->target_cluster_size) { |
| s->buf_size = MAX(s->buf_size, s->target_cluster_size); |
| s->cow_bitmap = bitmap_new(length); |
| } |
| 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 || job_is_cancelled(&s->common.job)) { |
| goto immediate_exit; |
| } |
| } |
| |
| assert(!s->dbi); |
| s->dbi = bdrv_dirty_iter_new(s->dirty_bitmap); |
| for (;;) { |
| uint64_t delay_ns = 0; |
| int64_t cnt, delta; |
| bool should_complete; |
| |
| /* Do not start passive operations while there are active |
| * writes in progress */ |
| while (s->in_active_write_counter) { |
| mirror_wait_for_any_operation(s, true); |
| } |
| |
| if (s->ret < 0) { |
| ret = s->ret; |
| goto immediate_exit; |
| } |
| |
| job_pause_point(&s->common.job); |
| |
| if (job_is_cancelled(&s->common.job)) { |
| ret = 0; |
| goto immediate_exit; |
| } |
| |
| cnt = bdrv_get_dirty_count(s->dirty_bitmap); |
| /* cnt is the number of dirty bytes remaining and s->bytes_in_flight is |
| * the number of bytes currently being processed; together those are |
| * the current remaining operation length */ |
| job_progress_set_remaining(&s->common.job, s->bytes_in_flight + cnt); |
| |
| /* 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 BLKOCK_JOB_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 < BLOCK_JOB_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, cnt, s->buf_free_count, s->in_flight); |
| mirror_wait_for_free_in_flight_slot(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); |
| if (!job_is_ready(&s->common.job)) { |
| if (mirror_flush(s) < 0) { |
| /* Go check s->ret. */ |
| continue; |
| } |
| /* 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. |
| */ |
| job_transition_to_ready(&s->common.job); |
| if (s->copy_mode != MIRROR_COPY_MODE_BACKGROUND) { |
| s->actively_synced = true; |
| } |
| } |
| |
| should_complete = s->should_complete || |
| job_cancel_requested(&s->common.job); |
| 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); |
| |
| s->in_drain = true; |
| bdrv_drained_begin(bs); |
| cnt = bdrv_get_dirty_count(s->dirty_bitmap); |
| if (cnt > 0 || mirror_flush(s) < 0) { |
| bdrv_drained_end(bs); |
| s->in_drain = false; |
| continue; |
| } |
| |
| /* The two disks are in sync. Exit and report successful |
| * completion. |
| */ |
| assert(QLIST_EMPTY(&bs->tracked_requests)); |
| need_drain = false; |
| break; |
| } |
| |
| if (job_is_ready(&s->common.job) && !should_complete) { |
| delay_ns = (s->in_flight == 0 && |
| cnt == 0 ? BLOCK_JOB_SLICE_TIME : 0); |
| } |
| trace_mirror_before_sleep(s, cnt, job_is_ready(&s->common.job), |
| delay_ns); |
| job_sleep_ns(&s->common.job, 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 || job_is_cancelled(&s->common.job)); |
| 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); |
| |
| if (need_drain) { |
| s->in_drain = true; |
| bdrv_drained_begin(bs); |
| } |
| |
| return ret; |
| } |
| |
| static void mirror_complete(Job *job, Error **errp) |
| { |
| MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job); |
| |
| if (!job_is_ready(job)) { |
| error_setg(errp, "The active block job '%s' cannot be completed", |
| job->id); |
| 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); |
| |
| /* TODO Translate this into child freeze system. */ |
| 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; |
| |
| /* If the job is paused, it will be re-entered when it is resumed */ |
| if (!job->paused) { |
| job_enter(job); |
| } |
| } |
| |
| static void coroutine_fn mirror_pause(Job *job) |
| { |
| MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job); |
| |
| mirror_wait_for_all_io(s); |
| } |
| |
| static bool mirror_drained_poll(BlockJob *job) |
| { |
| MirrorBlockJob *s = container_of(job, MirrorBlockJob, common); |
| |
| /* If the job isn't paused nor cancelled, we can't be sure that it won't |
| * issue more requests. We make an exception if we've reached this point |
| * from one of our own drain sections, to avoid a deadlock waiting for |
| * ourselves. |
| */ |
| if (!s->common.job.paused && !job_is_cancelled(&job->job) && !s->in_drain) { |
| return true; |
| } |
| |
| return !!s->in_flight; |
| } |
| |
| static bool mirror_cancel(Job *job, bool force) |
| { |
| MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job); |
| BlockDriverState *target = blk_bs(s->target); |
| |
| /* |
| * Before the job is READY, we treat any cancellation like a |
| * force-cancellation. |
| */ |
| force = force || !job_is_ready(job); |
| |
| if (force) { |
| bdrv_cancel_in_flight(target); |
| } |
| return force; |
| } |
| |
| static bool commit_active_cancel(Job *job, bool force) |
| { |
| /* Same as above in mirror_cancel() */ |
| return force || !job_is_ready(job); |
| } |
| |
| static const BlockJobDriver mirror_job_driver = { |
| .job_driver = { |
| .instance_size = sizeof(MirrorBlockJob), |
| .job_type = JOB_TYPE_MIRROR, |
| .free = block_job_free, |
| .user_resume = block_job_user_resume, |
| .run = mirror_run, |
| .prepare = mirror_prepare, |
| .abort = mirror_abort, |
| .pause = mirror_pause, |
| .complete = mirror_complete, |
| .cancel = mirror_cancel, |
| }, |
| .drained_poll = mirror_drained_poll, |
| }; |
| |
| static const BlockJobDriver commit_active_job_driver = { |
| .job_driver = { |
| .instance_size = sizeof(MirrorBlockJob), |
| .job_type = JOB_TYPE_COMMIT, |
| .free = block_job_free, |
| .user_resume = block_job_user_resume, |
| .run = mirror_run, |
| .prepare = mirror_prepare, |
| .abort = mirror_abort, |
| .pause = mirror_pause, |
| .complete = mirror_complete, |
| .cancel = commit_active_cancel, |
| }, |
| .drained_poll = mirror_drained_poll, |
| }; |
| |
| static void coroutine_fn |
| do_sync_target_write(MirrorBlockJob *job, MirrorMethod method, |
| uint64_t offset, uint64_t bytes, |
| QEMUIOVector *qiov, int flags) |
| { |
| int ret; |
| size_t qiov_offset = 0; |
| int64_t bitmap_offset, bitmap_end; |
| |
| if (!QEMU_IS_ALIGNED(offset, job->granularity) && |
| bdrv_dirty_bitmap_get(job->dirty_bitmap, offset)) |
| { |
| /* |
| * Dirty unaligned padding: ignore it. |
| * |
| * Reasoning: |
| * 1. If we copy it, we can't reset corresponding bit in |
| * dirty_bitmap as there may be some "dirty" bytes still not |
| * copied. |
| * 2. It's already dirty, so skipping it we don't diverge mirror |
| * progress. |
| * |
| * Note, that because of this, guest write may have no contribution |
| * into mirror converge, but that's not bad, as we have background |
| * process of mirroring. If under some bad circumstances (high guest |
| * IO load) background process starve, we will not converge anyway, |
| * even if each write will contribute, as guest is not guaranteed to |
| * rewrite the whole disk. |
| */ |
| qiov_offset = QEMU_ALIGN_UP(offset, job->granularity) - offset; |
| if (bytes <= qiov_offset) { |
| /* nothing to do after shrink */ |
| return; |
| } |
| offset += qiov_offset; |
| bytes -= qiov_offset; |
| } |
| |
| if (!QEMU_IS_ALIGNED(offset + bytes, job->granularity) && |
| bdrv_dirty_bitmap_get(job->dirty_bitmap, offset + bytes - 1)) |
| { |
| uint64_t tail = (offset + bytes) % job->granularity; |
| |
| if (bytes <= tail) { |
| /* nothing to do after shrink */ |
| return; |
| } |
| bytes -= tail; |
| } |
| |
| /* |
| * Tails are either clean or shrunk, so for bitmap resetting |
| * we safely align the range down. |
| */ |
| bitmap_offset = QEMU_ALIGN_UP(offset, job->granularity); |
| bitmap_end = QEMU_ALIGN_DOWN(offset + bytes, job->granularity); |
| if (bitmap_offset < bitmap_end) { |
| bdrv_reset_dirty_bitmap(job->dirty_bitmap, bitmap_offset, |
| bitmap_end - bitmap_offset); |
| } |
| |
| job_progress_increase_remaining(&job->common.job, bytes); |
| |
| switch (method) { |
| case MIRROR_METHOD_COPY: |
| ret = blk_co_pwritev_part(job->target, offset, bytes, |
| qiov, qiov_offset, flags); |
| break; |
| |
| case MIRROR_METHOD_ZERO: |
| assert(!qiov); |
| ret = blk_co_pwrite_zeroes(job->target, offset, bytes, flags); |
| break; |
| |
| case MIRROR_METHOD_DISCARD: |
| assert(!qiov); |
| ret = blk_co_pdiscard(job->target, offset, bytes); |
| break; |
| |
| default: |
| abort(); |
| } |
| |
| if (ret >= 0) { |
| job_progress_update(&job->common.job, bytes); |
| } else { |
| BlockErrorAction action; |
| |
| /* |
| * We failed, so we should mark dirty the whole area, aligned up. |
| * Note that we don't care about shrunk tails if any: they were dirty |
| * at function start, and they must be still dirty, as we've locked |
| * the region for in-flight op. |
| */ |
| bitmap_offset = QEMU_ALIGN_DOWN(offset, job->granularity); |
| bitmap_end = QEMU_ALIGN_UP(offset + bytes, job->granularity); |
| bdrv_set_dirty_bitmap(job->dirty_bitmap, bitmap_offset, |
| bitmap_end - bitmap_offset); |
| job->actively_synced = false; |
| |
| action = mirror_error_action(job, false, -ret); |
| if (action == BLOCK_ERROR_ACTION_REPORT) { |
| if (!job->ret) { |
| job->ret = ret; |
| } |
| } |
| } |
| } |
| |
| static MirrorOp *coroutine_fn active_write_prepare(MirrorBlockJob *s, |
| uint64_t offset, |
| uint64_t bytes) |
| { |
| MirrorOp *op; |
| uint64_t start_chunk = offset / s->granularity; |
| uint64_t end_chunk = DIV_ROUND_UP(offset + bytes, s->granularity); |
| |
| op = g_new(MirrorOp, 1); |
| *op = (MirrorOp){ |
| .s = s, |
| .offset = offset, |
| .bytes = bytes, |
| .is_active_write = true, |
| .is_in_flight = true, |
| .co = qemu_coroutine_self(), |
| }; |
| qemu_co_queue_init(&op->waiting_requests); |
| QTAILQ_INSERT_TAIL(&s->ops_in_flight, op, next); |
| |
| s->in_active_write_counter++; |
| |
| mirror_wait_on_conflicts(op, s, offset, bytes); |
| |
| bitmap_set(s->in_flight_bitmap, start_chunk, end_chunk - start_chunk); |
| |
| return op; |
| } |
| |
| static void coroutine_fn active_write_settle(MirrorOp *op) |
| { |
| uint64_t start_chunk = op->offset / op->s->granularity; |
| uint64_t end_chunk = DIV_ROUND_UP(op->offset + op->bytes, |
| op->s->granularity); |
| |
| if (!--op->s->in_active_write_counter && op->s->actively_synced) { |
| BdrvChild *source = op->s->mirror_top_bs->backing; |
| |
| if (QLIST_FIRST(&source->bs->parents) == source && |
| QLIST_NEXT(source, next_parent) == NULL) |
| { |
| /* Assert that we are back in sync once all active write |
| * operations are settled. |
| * Note that we can only assert this if the mirror node |
| * is the source node's only parent. */ |
| assert(!bdrv_get_dirty_count(op->s->dirty_bitmap)); |
| } |
| } |
| bitmap_clear(op->s->in_flight_bitmap, start_chunk, end_chunk - start_chunk); |
| QTAILQ_REMOVE(&op->s->ops_in_flight, op, next); |
| qemu_co_queue_restart_all(&op->waiting_requests); |
| g_free(op); |
| } |
| |
| static int coroutine_fn bdrv_mirror_top_preadv(BlockDriverState *bs, |
| int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags) |
| { |
| return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags); |
| } |
| |
| static int coroutine_fn bdrv_mirror_top_do_write(BlockDriverState *bs, |
| MirrorMethod method, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, |
| int flags) |
| { |
| MirrorOp *op = NULL; |
| MirrorBDSOpaque *s = bs->opaque; |
| int ret = 0; |
| bool copy_to_target; |
| |
| copy_to_target = s->job->ret >= 0 && |
| !job_is_cancelled(&s->job->common.job) && |
| s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING; |
| |
| if (copy_to_target) { |
| op = active_write_prepare(s->job, offset, bytes); |
| } |
| |
| switch (method) { |
| case MIRROR_METHOD_COPY: |
| ret = bdrv_co_pwritev(bs->backing, offset, bytes, qiov, flags); |
| break; |
| |
| case MIRROR_METHOD_ZERO: |
| ret = bdrv_co_pwrite_zeroes(bs->backing, offset, bytes, flags); |
| break; |
| |
| case MIRROR_METHOD_DISCARD: |
| ret = bdrv_co_pdiscard(bs->backing, offset, bytes); |
| break; |
| |
| default: |
| abort(); |
| } |
| |
| if (ret < 0) { |
| goto out; |
| } |
| |
| if (copy_to_target) { |
| do_sync_target_write(s->job, method, offset, bytes, qiov, flags); |
| } |
| |
| out: |
| if (copy_to_target) { |
| active_write_settle(op); |
| } |
| return ret; |
| } |
| |
| static int coroutine_fn bdrv_mirror_top_pwritev(BlockDriverState *bs, |
| int64_t offset, int64_t bytes, QEMUIOVector *qiov, BdrvRequestFlags flags) |
| { |
| MirrorBDSOpaque *s = bs->opaque; |
| QEMUIOVector bounce_qiov; |
| void *bounce_buf; |
| int ret = 0; |
| bool copy_to_target; |
| |
| copy_to_target = s->job->ret >= 0 && |
| !job_is_cancelled(&s->job->common.job) && |
| s->job->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING; |
| |
| if (copy_to_target) { |
| /* The guest might concurrently modify the data to write; but |
| * the data on source and destination must match, so we have |
| * to use a bounce buffer if we are going to write to the |
| * target now. */ |
| bounce_buf = qemu_blockalign(bs, bytes); |
| iov_to_buf_full(qiov->iov, qiov->niov, 0, bounce_buf, bytes); |
| |
| qemu_iovec_init(&bounce_qiov, 1); |
| qemu_iovec_add(&bounce_qiov, bounce_buf, bytes); |
| qiov = &bounce_qiov; |
| } |
| |
| ret = bdrv_mirror_top_do_write(bs, MIRROR_METHOD_COPY, offset, bytes, qiov, |
| flags); |
| |
| if (copy_to_target) { |
| qemu_iovec_destroy(&bounce_qiov); |
| qemu_vfree(bounce_buf); |
| } |
| |
| return ret; |
| } |
| |
| static int coroutine_fn bdrv_mirror_top_flush(BlockDriverState *bs) |
| { |
| if (bs->backing == NULL) { |
| /* we can be here after failed bdrv_append in mirror_start_job */ |
| return 0; |
| } |
| return bdrv_co_flush(bs->backing->bs); |
| } |
| |
| static int coroutine_fn bdrv_mirror_top_pwrite_zeroes(BlockDriverState *bs, |
| int64_t offset, int64_t bytes, BdrvRequestFlags flags) |
| { |
| return bdrv_mirror_top_do_write(bs, MIRROR_METHOD_ZERO, offset, bytes, NULL, |
| flags); |
| } |
| |
| static int coroutine_fn bdrv_mirror_top_pdiscard(BlockDriverState *bs, |
| int64_t offset, int64_t bytes) |
| { |
| return bdrv_mirror_top_do_write(bs, MIRROR_METHOD_DISCARD, offset, bytes, |
| NULL, 0); |
| } |
| |
| static void bdrv_mirror_top_refresh_filename(BlockDriverState *bs) |
| { |
| if (bs->backing == NULL) { |
| /* we can be here after failed bdrv_attach_child in |
| * bdrv_set_backing_hd */ |
| return; |
| } |
| pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), |
| bs->backing->bs->filename); |
| } |
| |
| static void bdrv_mirror_top_child_perm(BlockDriverState *bs, BdrvChild *c, |
| BdrvChildRole role, |
| BlockReopenQueue *reopen_queue, |
| uint64_t perm, uint64_t shared, |
| uint64_t *nperm, uint64_t *nshared) |
| { |
| MirrorBDSOpaque *s = bs->opaque; |
| |
| if (s->stop) { |
| /* |
| * If the job is to be stopped, we do not need to forward |
| * anything to the real image. |
| */ |
| *nperm = 0; |
| *nshared = BLK_PERM_ALL; |
| return; |
| } |
| |
| bdrv_default_perms(bs, c, role, reopen_queue, |
| perm, shared, nperm, nshared); |
| |
| if (s->is_commit) { |
| /* |
| * For commit jobs, we cannot take CONSISTENT_READ, because |
| * that permission is unshared for everything above the base |
| * node (except for filters on the base node). |
| * We also have to force-share the WRITE permission, or |
| * otherwise we would block ourselves at the base node (if |
| * writes are blocked for a node, they are also blocked for |
| * its backing file). |
| * (We could also share RESIZE, because it may be needed for |
| * the target if its size is less than the top node's; but |
| * bdrv_default_perms_for_cow() automatically shares RESIZE |
| * for backing nodes if WRITE is shared, so there is no need |
| * to do it here.) |
| */ |
| *nperm &= ~BLK_PERM_CONSISTENT_READ; |
| *nshared |= BLK_PERM_WRITE; |
| } |
| } |
| |
| /* Dummy node that provides consistent read to its users without requiring it |
| * from its backing file and that allows writes on the backing file chain. */ |
| static BlockDriver bdrv_mirror_top = { |
| .format_name = "mirror_top", |
| .bdrv_co_preadv = bdrv_mirror_top_preadv, |
| .bdrv_co_pwritev = bdrv_mirror_top_pwritev, |
| .bdrv_co_pwrite_zeroes = bdrv_mirror_top_pwrite_zeroes, |
| .bdrv_co_pdiscard = bdrv_mirror_top_pdiscard, |
| .bdrv_co_flush = bdrv_mirror_top_flush, |
| .bdrv_refresh_filename = bdrv_mirror_top_refresh_filename, |
| .bdrv_child_perm = bdrv_mirror_top_child_perm, |
| |
| .is_filter = true, |
| }; |
| |
| static BlockJob *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, |
| bool zero_target, |
| BlockdevOnError on_source_error, |
| BlockdevOnError on_target_error, |
| bool unmap, |
| BlockCompletionFunc *cb, |
| void *opaque, |
| const BlockJobDriver *driver, |
| bool is_none_mode, BlockDriverState *base, |
| bool auto_complete, const char *filter_node_name, |
| bool is_mirror, MirrorCopyMode copy_mode, |
| Error **errp) |
| { |
| MirrorBlockJob *s; |
| MirrorBDSOpaque *bs_opaque; |
| BlockDriverState *mirror_top_bs; |
| bool target_is_backing; |
| uint64_t target_perms, target_shared_perms; |
| int ret; |
| |
| if (granularity == 0) { |
| granularity = bdrv_get_default_bitmap_granularity(target); |
| } |
| |
| assert(is_power_of_2(granularity)); |
| |
| if (buf_size < 0) { |
| error_setg(errp, "Invalid parameter 'buf-size'"); |
| return NULL; |
| } |
| |
| if (buf_size == 0) { |
| buf_size = DEFAULT_MIRROR_BUF_SIZE; |
| } |
| |
| if (bdrv_skip_filters(bs) == bdrv_skip_filters(target)) { |
| error_setg(errp, "Can't mirror node into itself"); |
| return NULL; |
| } |
| |
| target_is_backing = bdrv_chain_contains(bs, target); |
| |
| /* In the case of active commit, add dummy driver to provide consistent |
| * reads on the top, while disabling it in the intermediate nodes, and make |
| * the backing chain writable. */ |
| mirror_top_bs = bdrv_new_open_driver(&bdrv_mirror_top, filter_node_name, |
| BDRV_O_RDWR, errp); |
| if (mirror_top_bs == NULL) { |
| return NULL; |
| } |
| if (!filter_node_name) { |
| mirror_top_bs->implicit = true; |
| } |
| |
| /* So that we can always drop this node */ |
| mirror_top_bs->never_freeze = true; |
| |
| mirror_top_bs->total_sectors = bs->total_sectors; |
| mirror_top_bs->supported_write_flags = BDRV_REQ_WRITE_UNCHANGED; |
| mirror_top_bs->supported_zero_flags = BDRV_REQ_WRITE_UNCHANGED | |
| BDRV_REQ_NO_FALLBACK; |
| bs_opaque = g_new0(MirrorBDSOpaque, 1); |
| mirror_top_bs->opaque = bs_opaque; |
| |
| bs_opaque->is_commit = target_is_backing; |
| |
| bdrv_drained_begin(bs); |
| ret = bdrv_append(mirror_top_bs, bs, errp); |
| bdrv_drained_end(bs); |
| |
| if (ret < 0) { |
| bdrv_unref(mirror_top_bs); |
| return NULL; |
| } |
| |
| /* Make sure that the source is not resized while the job is running */ |
| s = block_job_create(job_id, driver, NULL, mirror_top_bs, |
| BLK_PERM_CONSISTENT_READ, |
| BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED | |
| BLK_PERM_WRITE, speed, |
| creation_flags, cb, opaque, errp); |
| if (!s) { |
| goto fail; |
| } |
| bs_opaque->job = s; |
| |
| /* The block job now has a reference to this node */ |
| bdrv_unref(mirror_top_bs); |
| |
| s->mirror_top_bs = mirror_top_bs; |
| |
| /* No resize for the target either; while the mirror is still running, a |
| * consistent read isn't necessarily possible. We could possibly allow |
| * writes and graph modifications, though it would likely defeat the |
| * purpose of a mirror, so leave them blocked for now. |
| * |
| * In the case of active commit, things look a bit different, though, |
| * because the target is an already populated backing file in active use. |
| * We can allow anything except resize there.*/ |
| |
| target_perms = BLK_PERM_WRITE; |
| target_shared_perms = BLK_PERM_WRITE_UNCHANGED; |
| |
| if (target_is_backing) { |
| int64_t bs_size, target_size; |
| bs_size = bdrv_getlength(bs); |
| if (bs_size < 0) { |
| error_setg_errno(errp, -bs_size, |
| "Could not inquire top image size"); |
| goto fail; |
| } |
| |
| target_size = bdrv_getlength(target); |
| if (target_size < 0) { |
| error_setg_errno(errp, -target_size, |
| "Could not inquire base image size"); |
| goto fail; |
| } |
| |
| if (target_size < bs_size) { |
| target_perms |= BLK_PERM_RESIZE; |
| } |
| |
| target_shared_perms |= BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE; |
| } else if (bdrv_chain_contains(bs, bdrv_skip_filters(target))) { |
| /* |
| * We may want to allow this in the future, but it would |
| * require taking some extra care. |
| */ |
| error_setg(errp, "Cannot mirror to a filter on top of a node in the " |
| "source's backing chain"); |
| goto fail; |
| } |
| |
| s->target = blk_new(s->common.job.aio_context, |
| target_perms, target_shared_perms); |
| ret = blk_insert_bs(s->target, target, errp); |
| if (ret < 0) { |
| goto fail; |
| } |
| if (is_mirror) { |
| /* XXX: Mirror target could be a NBD server of target QEMU in the case |
| * of non-shared block migration. To allow migration completion, we |
| * have to allow "inactivate" of the target BB. When that happens, we |
| * know the job is drained, and the vcpus are stopped, so no write |
| * operation will be performed. Block layer already has assertions to |
| * ensure that. */ |
| blk_set_force_allow_inactivate(s->target); |
| } |
| blk_set_allow_aio_context_change(s->target, true); |
| blk_set_disable_request_queuing(s->target, true); |
| |
| 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->zero_target = zero_target; |
| s->copy_mode = copy_mode; |
| s->base = base; |
| s->base_overlay = bdrv_find_overlay(bs, 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) { |
| goto fail; |
| } |
| if (s->copy_mode == MIRROR_COPY_MODE_WRITE_BLOCKING) { |
| bdrv_disable_dirty_bitmap(s->dirty_bitmap); |
| } |
| |
| ret = block_job_add_bdrv(&s->common, "source", bs, 0, |
| BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE | |
| BLK_PERM_CONSISTENT_READ, |
| errp); |
| if (ret < 0) { |
| goto fail; |
| } |
| |
| /* Required permissions are already taken with blk_new() */ |
| block_job_add_bdrv(&s->common, "target", target, 0, BLK_PERM_ALL, |
| &error_abort); |
| |
| /* In commit_active_start() all intermediate nodes disappear, so |
| * any jobs in them must be blocked */ |
| if (target_is_backing) { |
| BlockDriverState *iter, *filtered_target; |
| uint64_t iter_shared_perms; |
| |
| /* |
| * The topmost node with |
| * bdrv_skip_filters(filtered_target) == bdrv_skip_filters(target) |
| */ |
| filtered_target = bdrv_cow_bs(bdrv_find_overlay(bs, target)); |
| |
| assert(bdrv_skip_filters(filtered_target) == |
| bdrv_skip_filters(target)); |
| |
| /* |
| * XXX BLK_PERM_WRITE needs to be allowed so we don't block |
| * ourselves at s->base (if writes are blocked for a node, they are |
| * also blocked for its backing file). The other options would be a |
| * second filter driver above s->base (== target). |
| */ |
| iter_shared_perms = BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE; |
| |
| for (iter = bdrv_filter_or_cow_bs(bs); iter != target; |
| iter = bdrv_filter_or_cow_bs(iter)) |
| { |
| if (iter == filtered_target) { |
| /* |
| * From here on, all nodes are filters on the base. |
| * This allows us to share BLK_PERM_CONSISTENT_READ. |
| */ |
| iter_shared_perms |= BLK_PERM_CONSISTENT_READ; |
| } |
| |
| ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0, |
| iter_shared_perms, errp); |
| if (ret < 0) { |
| goto fail; |
| } |
| } |
| |
| if (bdrv_freeze_backing_chain(mirror_top_bs, target, errp) < 0) { |
| goto fail; |
| } |
| } |
| |
| QTAILQ_INIT(&s->ops_in_flight); |
| |
| trace_mirror_start(bs, s, opaque); |
| job_start(&s->common.job); |
| |
| return &s->common; |
| |
| fail: |
| if (s) { |
| /* Make sure this BDS does not go away until we have completed the graph |
| * changes below */ |
| bdrv_ref(mirror_top_bs); |
| |
| g_free(s->replaces); |
| blk_unref(s->target); |
| bs_opaque->job = NULL; |
| if (s->dirty_bitmap) { |
| bdrv_release_dirty_bitmap(s->dirty_bitmap); |
| } |
| job_early_fail(&s->common.job); |
| } |
| |
| bs_opaque->stop = true; |
| bdrv_child_refresh_perms(mirror_top_bs, mirror_top_bs->backing, |
| &error_abort); |
| bdrv_replace_node(mirror_top_bs, mirror_top_bs->backing->bs, &error_abort); |
| |
| bdrv_unref(mirror_top_bs); |
| |
| return NULL; |
| } |
| |
| void mirror_start(const char *job_id, BlockDriverState *bs, |
| BlockDriverState *target, const char *replaces, |
| int creation_flags, int64_t speed, |
| uint32_t granularity, int64_t buf_size, |
| MirrorSyncMode mode, BlockMirrorBackingMode backing_mode, |
| bool zero_target, |
| BlockdevOnError on_source_error, |
| BlockdevOnError on_target_error, |
| bool unmap, const char *filter_node_name, |
| MirrorCopyMode copy_mode, Error **errp) |
| { |
| bool is_none_mode; |
| BlockDriverState *base; |
| |
| GLOBAL_STATE_CODE(); |
| |
| if ((mode == MIRROR_SYNC_MODE_INCREMENTAL) || |
| (mode == MIRROR_SYNC_MODE_BITMAP)) { |
| error_setg(errp, "Sync mode '%s' not supported", |
| MirrorSyncMode_str(mode)); |
| return; |
| } |
| is_none_mode = mode == MIRROR_SYNC_MODE_NONE; |
| base = mode == MIRROR_SYNC_MODE_TOP ? bdrv_backing_chain_next(bs) : NULL; |
| mirror_start_job(job_id, bs, creation_flags, target, replaces, |
| speed, granularity, buf_size, backing_mode, zero_target, |
| on_source_error, on_target_error, unmap, NULL, NULL, |
| &mirror_job_driver, is_none_mode, base, false, |
| filter_node_name, true, copy_mode, errp); |
| } |
| |
| BlockJob *commit_active_start(const char *job_id, BlockDriverState *bs, |
| BlockDriverState *base, int creation_flags, |
| int64_t speed, BlockdevOnError on_error, |
| const char *filter_node_name, |
| BlockCompletionFunc *cb, void *opaque, |
| bool auto_complete, Error **errp) |
| { |
| bool base_read_only; |
| BlockJob *job; |
| |
| GLOBAL_STATE_CODE(); |
| |
| base_read_only = bdrv_is_read_only(base); |
| |
| if (base_read_only) { |
| if (bdrv_reopen_set_read_only(base, false, errp) < 0) { |
| return NULL; |
| } |
| } |
| |
| job = mirror_start_job( |
| job_id, bs, creation_flags, base, NULL, speed, 0, 0, |
| MIRROR_LEAVE_BACKING_CHAIN, false, |
| on_error, on_error, true, cb, opaque, |
| &commit_active_job_driver, false, base, auto_complete, |
| filter_node_name, false, MIRROR_COPY_MODE_BACKGROUND, |
| errp); |
| if (!job) { |
| goto error_restore_flags; |
| } |
| |
| return job; |
| |
| error_restore_flags: |
| /* ignore error and errp for bdrv_reopen, because we want to propagate |
| * the original error */ |
| if (base_read_only) { |
| bdrv_reopen_set_read_only(base, true, NULL); |
| } |
| return NULL; |
| } |