X-Git-Url: https://repo.jachan.dev/qemu.git/blobdiff_plain/c416eecea5f3aea863ab8fda5a36a24157b8f704..ece09beec457:/block/commit.c diff --git a/block/commit.c b/block/commit.c index ba5df6aa0a..212c6f639e 100644 --- a/block/commit.c +++ b/block/commit.c @@ -36,8 +36,10 @@ typedef struct CommitBlockJob { BlockDriverState *commit_top_bs; BlockBackend *top; BlockBackend *base; + BlockDriverState *base_bs; BlockdevOnError on_error; - int base_flags; + bool base_read_only; + bool chain_frozen; char *backing_file_str; } CommitBlockJob; @@ -46,21 +48,15 @@ static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base, void *buf) { int ret = 0; - QEMUIOVector qiov; - struct iovec iov = { - .iov_base = buf, - .iov_len = bytes, - }; assert(bytes < SIZE_MAX); - qemu_iovec_init_external(&qiov, &iov, 1); - ret = blk_co_preadv(bs, offset, qiov.size, &qiov, 0); + ret = blk_co_pread(bs, offset, bytes, buf, 0); if (ret < 0) { return ret; } - ret = blk_co_pwritev(base, offset, qiov.size, &qiov, 0); + ret = blk_co_pwrite(base, offset, bytes, buf, 0); if (ret < 0) { return ret; } @@ -68,75 +64,77 @@ static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base, return 0; } -typedef struct { - int ret; -} CommitCompleteData; - -static void commit_complete(BlockJob *job, void *opaque) +static int commit_prepare(Job *job) { - CommitBlockJob *s = container_of(job, CommitBlockJob, common); - CommitCompleteData *data = opaque; - BlockDriverState *top = blk_bs(s->top); - BlockDriverState *base = blk_bs(s->base); - BlockDriverState *commit_top_bs = s->commit_top_bs; - int ret = data->ret; - bool remove_commit_top_bs = false; + CommitBlockJob *s = container_of(job, CommitBlockJob, common.job); - /* Make sure commit_top_bs and top stay around until bdrv_replace_node() */ - bdrv_ref(top); - bdrv_ref(commit_top_bs); + bdrv_unfreeze_backing_chain(s->commit_top_bs, s->base_bs); + s->chain_frozen = false; /* Remove base node parent that still uses BLK_PERM_WRITE/RESIZE before * the normal backing chain can be restored. */ blk_unref(s->base); + s->base = NULL; - if (!block_job_is_cancelled(&s->common) && ret == 0) { - /* success */ - ret = bdrv_drop_intermediate(s->commit_top_bs, base, - s->backing_file_str); - } else { - /* XXX Can (or should) we somehow keep 'consistent read' blocked even - * after the failed/cancelled commit job is gone? If we already wrote - * something to base, the intermediate images aren't valid any more. */ - remove_commit_top_bs = true; + /* FIXME: bdrv_drop_intermediate treats total failures and partial failures + * identically. Further work is needed to disambiguate these cases. */ + return bdrv_drop_intermediate(s->commit_top_bs, s->base_bs, + s->backing_file_str); +} + +static void commit_abort(Job *job) +{ + CommitBlockJob *s = container_of(job, CommitBlockJob, common.job); + BlockDriverState *top_bs = blk_bs(s->top); + + if (s->chain_frozen) { + bdrv_unfreeze_backing_chain(s->commit_top_bs, s->base_bs); } - /* restore base open flags here if appropriate (e.g., change the base back - * to r/o). These reopens do not need to be atomic, since we won't abort - * even on failure here */ - if (s->base_flags != bdrv_get_flags(base)) { - bdrv_reopen(base, s->base_flags, NULL); + /* Make sure commit_top_bs and top stay around until bdrv_replace_node() */ + bdrv_ref(top_bs); + bdrv_ref(s->commit_top_bs); + + if (s->base) { + blk_unref(s->base); } - g_free(s->backing_file_str); - blk_unref(s->top); - /* If there is more than one reference to the job (e.g. if called from - * block_job_finish_sync()), block_job_completed() won't free it and - * therefore the blockers on the intermediate nodes remain. This would - * cause bdrv_set_backing_hd() to fail. */ - block_job_remove_all_bdrv(job); + /* free the blockers on the intermediate nodes so that bdrv_replace_nodes + * can succeed */ + block_job_remove_all_bdrv(&s->common); - block_job_completed(&s->common, ret); - g_free(data); + /* If bdrv_drop_intermediate() failed (or was not invoked), remove the + * commit filter driver from the backing chain now. Do this as the final + * step so that the 'consistent read' permission can be granted. + * + * XXX Can (or should) we somehow keep 'consistent read' blocked even + * after the failed/cancelled commit job is gone? If we already wrote + * something to base, the intermediate images aren't valid any more. */ + bdrv_replace_node(s->commit_top_bs, backing_bs(s->commit_top_bs), + &error_abort); - /* If bdrv_drop_intermediate() didn't already do that, remove the commit - * filter driver from the backing chain. Do this as the final step so that - * the 'consistent read' permission can be granted. */ - if (remove_commit_top_bs) { - bdrv_child_try_set_perm(commit_top_bs->backing, 0, BLK_PERM_ALL, - &error_abort); - bdrv_replace_node(commit_top_bs, backing_bs(commit_top_bs), - &error_abort); + bdrv_unref(s->commit_top_bs); + bdrv_unref(top_bs); +} + +static void commit_clean(Job *job) +{ + CommitBlockJob *s = container_of(job, CommitBlockJob, common.job); + + /* restore base open flags here if appropriate (e.g., change the base back + * to r/o). These reopens do not need to be atomic, since we won't abort + * even on failure here */ + if (s->base_read_only) { + bdrv_reopen_set_read_only(s->base_bs, true, NULL); } - bdrv_unref(commit_top_bs); - bdrv_unref(top); + g_free(s->backing_file_str); + blk_unref(s->top); } -static void coroutine_fn commit_run(void *opaque) +static int coroutine_fn commit_run(Job *job, Error **errp) { - CommitBlockJob *s = opaque; - CommitCompleteData *data; + CommitBlockJob *s = container_of(job, CommitBlockJob, common.job); int64_t offset; uint64_t delay_ns = 0; int ret = 0; @@ -149,7 +147,7 @@ static void coroutine_fn commit_run(void *opaque) if (len < 0) { goto out; } - block_job_progress_set_remaining(&s->common, len); + job_progress_set_remaining(&s->common.job, len); ret = base_len = blk_getlength(s->base); if (base_len < 0) { @@ -171,8 +169,8 @@ static void coroutine_fn commit_run(void *opaque) /* Note that even when no rate limit is applied we need to yield * with no pending I/O here so that bdrv_drain_all() returns. */ - block_job_sleep_ns(&s->common, delay_ns); - if (block_job_is_cancelled(&s->common)) { + job_sleep_ns(&s->common.job, delay_ns); + if (job_is_cancelled(&s->common.job)) { break; } /* Copy if allocated above the base */ @@ -195,7 +193,7 @@ static void coroutine_fn commit_run(void *opaque) } } /* Publish progress */ - block_job_progress_update(&s->common, n); + job_progress_update(&s->common.job, n); if (copy) { delay_ns = block_job_ratelimit_get_delay(&s->common, n); @@ -209,15 +207,21 @@ static void coroutine_fn commit_run(void *opaque) out: qemu_vfree(buf); - data = g_malloc(sizeof(*data)); - data->ret = ret; - block_job_defer_to_main_loop(&s->common, commit_complete, data); + return ret; } static const BlockJobDriver commit_job_driver = { - .instance_size = sizeof(CommitBlockJob), - .job_type = BLOCK_JOB_TYPE_COMMIT, - .start = commit_run, + .job_driver = { + .instance_size = sizeof(CommitBlockJob), + .job_type = JOB_TYPE_COMMIT, + .free = block_job_free, + .user_resume = block_job_user_resume, + .drain = block_job_drain, + .run = commit_run, + .prepare = commit_prepare, + .abort = commit_abort, + .clean = commit_clean + }, }; static int coroutine_fn bdrv_commit_top_preadv(BlockDriverState *bs, @@ -226,17 +230,12 @@ static int coroutine_fn bdrv_commit_top_preadv(BlockDriverState *bs, return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags); } -static void bdrv_commit_top_refresh_filename(BlockDriverState *bs, QDict *opts) +static void bdrv_commit_top_refresh_filename(BlockDriverState *bs) { - bdrv_refresh_filename(bs->backing->bs); pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->backing->bs->filename); } -static void bdrv_commit_top_close(BlockDriverState *bs) -{ -} - static void bdrv_commit_top_child_perm(BlockDriverState *bs, BdrvChild *c, const BdrvChildRole *role, BlockReopenQueue *reopen_queue, @@ -254,17 +253,16 @@ static BlockDriver bdrv_commit_top = { .bdrv_co_preadv = bdrv_commit_top_preadv, .bdrv_co_block_status = bdrv_co_block_status_from_backing, .bdrv_refresh_filename = bdrv_commit_top_refresh_filename, - .bdrv_close = bdrv_commit_top_close, .bdrv_child_perm = bdrv_commit_top_child_perm, }; void commit_start(const char *job_id, BlockDriverState *bs, - BlockDriverState *base, BlockDriverState *top, int64_t speed, + BlockDriverState *base, BlockDriverState *top, + int creation_flags, int64_t speed, BlockdevOnError on_error, const char *backing_file_str, const char *filter_node_name, Error **errp) { CommitBlockJob *s; - int orig_base_flags; BlockDriverState *iter; BlockDriverState *commit_top_bs = NULL; Error *local_err = NULL; @@ -277,17 +275,15 @@ void commit_start(const char *job_id, BlockDriverState *bs, } s = block_job_create(job_id, &commit_job_driver, NULL, bs, 0, BLK_PERM_ALL, - speed, BLOCK_JOB_DEFAULT, NULL, NULL, errp); + speed, creation_flags, NULL, NULL, errp); if (!s) { return; } /* convert base to r/w, if necessary */ - orig_base_flags = bdrv_get_flags(base); - if (!(orig_base_flags & BDRV_O_RDWR)) { - bdrv_reopen(base, orig_base_flags | BDRV_O_RDWR, &local_err); - if (local_err != NULL) { - error_propagate(errp, local_err); + s->base_read_only = bdrv_is_read_only(base); + if (s->base_read_only) { + if (bdrv_reopen_set_read_only(base, false, errp) != 0) { goto fail; } } @@ -303,25 +299,15 @@ void commit_start(const char *job_id, BlockDriverState *bs, commit_top_bs->implicit = true; } commit_top_bs->total_sectors = top->total_sectors; - bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(top)); - bdrv_set_backing_hd(commit_top_bs, top, &local_err); + bdrv_append(commit_top_bs, top, &local_err); if (local_err) { - bdrv_unref(commit_top_bs); - commit_top_bs = NULL; - error_propagate(errp, local_err); - goto fail; - } - bdrv_replace_node(top, commit_top_bs, &local_err); - if (local_err) { - bdrv_unref(commit_top_bs); commit_top_bs = NULL; error_propagate(errp, local_err); goto fail; } s->commit_top_bs = commit_top_bs; - bdrv_unref(commit_top_bs); /* Block all nodes between top and base, because they will * disappear from the chain after this operation. */ @@ -339,12 +325,18 @@ void commit_start(const char *job_id, BlockDriverState *bs, } } + if (bdrv_freeze_backing_chain(commit_top_bs, base, errp) < 0) { + goto fail; + } + s->chain_frozen = true; + ret = block_job_add_bdrv(&s->common, "base", base, 0, BLK_PERM_ALL, errp); if (ret < 0) { goto fail; } - s->base = blk_new(BLK_PERM_CONSISTENT_READ + s->base = blk_new(s->common.job.aio_context, + BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_CONSISTENT_READ @@ -354,33 +346,41 @@ void commit_start(const char *job_id, BlockDriverState *bs, if (ret < 0) { goto fail; } + s->base_bs = base; /* Required permissions are already taken with block_job_add_bdrv() */ - s->top = blk_new(0, BLK_PERM_ALL); + s->top = blk_new(s->common.job.aio_context, 0, BLK_PERM_ALL); ret = blk_insert_bs(s->top, top, errp); if (ret < 0) { goto fail; } - s->base_flags = orig_base_flags; s->backing_file_str = g_strdup(backing_file_str); s->on_error = on_error; trace_commit_start(bs, base, top, s); - block_job_start(&s->common); + job_start(&s->common.job); return; fail: + if (s->chain_frozen) { + bdrv_unfreeze_backing_chain(commit_top_bs, base); + } if (s->base) { blk_unref(s->base); } if (s->top) { blk_unref(s->top); } + if (s->base_read_only) { + bdrv_reopen_set_read_only(base, true, NULL); + } + job_early_fail(&s->common.job); + /* commit_top_bs has to be replaced after deleting the block job, + * otherwise this would fail because of lack of permissions. */ if (commit_top_bs) { bdrv_replace_node(commit_top_bs, top, &error_abort); } - block_job_early_fail(&s->common); } @@ -393,8 +393,9 @@ int bdrv_commit(BlockDriverState *bs) BlockDriverState *backing_file_bs = NULL; BlockDriverState *commit_top_bs = NULL; BlockDriver *drv = bs->drv; + AioContext *ctx; int64_t offset, length, backing_length; - int ro, open_flags; + int ro; int64_t n; int ret = 0; uint8_t *buf = NULL; @@ -413,16 +414,16 @@ int bdrv_commit(BlockDriverState *bs) } ro = bs->backing->bs->read_only; - open_flags = bs->backing->bs->open_flags; if (ro) { - if (bdrv_reopen(bs->backing->bs, open_flags | BDRV_O_RDWR, NULL)) { + if (bdrv_reopen_set_read_only(bs->backing->bs, false, NULL)) { return -EACCES; } } - src = blk_new(BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL); - backing = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); + ctx = bdrv_get_aio_context(bs); + src = blk_new(ctx, BLK_PERM_CONSISTENT_READ, BLK_PERM_ALL); + backing = blk_new(ctx, BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); ret = blk_insert_bs(src, bs, &local_err); if (ret < 0) { @@ -439,7 +440,6 @@ int bdrv_commit(BlockDriverState *bs) error_report_err(local_err); goto ro_cleanup; } - bdrv_set_aio_context(commit_top_bs, bdrv_get_aio_context(backing_file_bs)); bdrv_set_backing_hd(commit_top_bs, backing_file_bs, &error_abort); bdrv_set_backing_hd(bs, commit_top_bs, &error_abort); @@ -526,7 +526,7 @@ ro_cleanup: if (ro) { /* ignoring error return here */ - bdrv_reopen(bs->backing->bs, open_flags & ~BDRV_O_RDWR, NULL); + bdrv_reopen_set_read_only(bs->backing->bs, true, NULL); } return ret;