static void parse_drive(DeviceState *dev, const char *str, void **ptr,
                        const char *propname, Error **errp)
{
    BlockBackend *blk;
    bool blk_created = false;
    int ret;

    blk = blk_by_name(str);
    if (!blk) {
        BlockDriverState *bs = bdrv_lookup_bs(NULL, str, NULL);
        if (bs) {
            blk = blk_new(0, BLK_PERM_ALL);
            blk_created = true;

            ret = blk_insert_bs(blk, bs, errp);
            if (ret < 0) {
                goto fail;
            }
        }
    }
    if (!blk) {
        error_setg(errp, "Property '%s.%s' can't find value '%s'",
                   object_get_typename(OBJECT(dev)), propname, str);
        goto fail;
    }
    if (blk_attach_dev(blk, dev) < 0) {
        DriveInfo *dinfo = blk_legacy_dinfo(blk);

        if (dinfo && dinfo->type != IF_NONE) {
            error_setg(errp, "Drive '%s' is already in use because "
                       "it has been automatically connected to another "
                       "device (did you need 'if=none' in the drive options?)",
                       str);
        } else {
            error_setg(errp, "Drive '%s' is already in use by another device",
                       str);
        }
        goto fail;
    }

    *ptr = blk;

fail:
    if (blk_created) {
        /* If we need to keep a reference, blk_attach_dev() took it */
        blk_unref(blk);
    }
}
示例#2
0
文件: mirror.c 项目: jiapei100/qemu
static void mirror_exit(BlockJob *job, void *opaque)
{
    MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
    MirrorExitData *data = opaque;
    AioContext *replace_aio_context = NULL;
    BlockDriverState *src = s->source;
    BlockDriverState *target_bs = blk_bs(s->target);
    BlockDriverState *mirror_top_bs = s->mirror_top_bs;
    Error *local_err = NULL;

    bdrv_release_dirty_bitmap(src, s->dirty_bitmap);

    /* Make sure that the source BDS doesn't go away before we called
     * block_job_completed(). */
    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.
     *
     * Note that blk_unref() alone doesn't necessarily drop permissions because
     * we might be running nested inside mirror_drain(), which takes an extra
     * reference, so use an explicit blk_set_perm() first. */
    blk_set_perm(s->target, 0, BLK_PERM_ALL, &error_abort);
    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. */
    bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL,
                            &error_abort);
    if (s->backing_mode == MIRROR_SOURCE_BACKING_CHAIN) {
        BlockDriverState *backing = s->is_none_mode ? src : s->base;
        if (backing_bs(target_bs) != backing) {
            bdrv_set_backing_hd(target_bs, backing, &local_err);
            if (local_err) {
                error_report_err(local_err);
                data->ret = -EPERM;
            }
        }
    }

    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_node(to_replace, target_bs, &local_err);
        bdrv_drained_end(target_bs);
        if (local_err) {
            error_report_err(local_err);
            data->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. Also give up permissions on mirror_top_bs->backing, which might
     * block the removal. */
    block_job_remove_all_bdrv(job);
    bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL,
                            &error_abort);
    bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort);

    /* We just changed the BDS the job BB refers to (with either or both of the
     * bdrv_replace_node() calls), so switch the BB back so the cleanup does
     * the right thing. We don't need any permissions any more now. */
    blk_remove_bs(job->blk);
    blk_set_perm(job->blk, 0, BLK_PERM_ALL, &error_abort);
    blk_insert_bs(job->blk, mirror_top_bs, &error_abort);

    block_job_completed(&s->common, data->ret);

    g_free(data);
    bdrv_drained_end(src);
    bdrv_unref(mirror_top_bs);
    bdrv_unref(src);
}
示例#3
0
文件: mirror.c 项目: jiapei100/qemu
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,
                             const BlockJobDriver *driver,
                             bool is_none_mode, BlockDriverState *base,
                             bool auto_complete, const char *filter_node_name,
                             bool is_mirror,
                             Error **errp)
{
    MirrorBlockJob *s;
    BlockDriverState *mirror_top_bs;
    bool target_graph_mod;
    bool target_is_backing;
    Error *local_err = NULL;
    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;
    }

    if (buf_size == 0) {
        buf_size = DEFAULT_MIRROR_BUF_SIZE;
    }

    /* 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;
    }
    if (!filter_node_name) {
        mirror_top_bs->implicit = 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_set_aio_context(mirror_top_bs, bdrv_get_aio_context(bs));

    /* bdrv_append takes ownership of the mirror_top_bs reference, need to keep
     * it alive until block_job_create() succeeds even if bs has no parent. */
    bdrv_ref(mirror_top_bs);
    bdrv_drained_begin(bs);
    bdrv_append(mirror_top_bs, bs, &local_err);
    bdrv_drained_end(bs);

    if (local_err) {
        bdrv_unref(mirror_top_bs);
        error_propagate(errp, local_err);
        return;
    }

    /* 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 | BLK_PERM_GRAPH_MOD, speed,
                         creation_flags, cb, opaque, errp);
    if (!s) {
        goto fail;
    }
    /* The block job now has a reference to this node */
    bdrv_unref(mirror_top_bs);

    s->source = 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_is_backing = bdrv_chain_contains(bs, target);
    target_graph_mod = (backing_mode != MIRROR_LEAVE_BACKING_CHAIN);
    s->target = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE |
                        (target_graph_mod ? BLK_PERM_GRAPH_MOD : 0),
                        BLK_PERM_WRITE_UNCHANGED |
                        (target_is_backing ? BLK_PERM_CONSISTENT_READ |
                                             BLK_PERM_WRITE |
                                             BLK_PERM_GRAPH_MOD : 0));
    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);
    }

    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) {
        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;
        for (iter = backing_bs(bs); iter != target; iter = backing_bs(iter)) {
            /* 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). */
            ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
                                     BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE,
                                     errp);
            if (ret < 0) {
                goto fail;
            }
        }
    }

    trace_mirror_start(bs, s, opaque);
    block_job_start(&s->common);
    return;

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);
        block_job_early_fail(&s->common);
    }

    bdrv_child_try_set_perm(mirror_top_bs->backing, 0, BLK_PERM_ALL,
                            &error_abort);
    bdrv_replace_node(mirror_top_bs, backing_bs(mirror_top_bs), &error_abort);

    bdrv_unref(mirror_top_bs);
}
示例#4
0
文件: commit.c 项目: MaddTheSane/qemu
/* commit COW file into the raw image */
int bdrv_commit(BlockDriverState *bs)
{
    BlockBackend *src, *backing;
    BlockDriverState *backing_file_bs = NULL;
    BlockDriverState *commit_top_bs = NULL;
    BlockDriver *drv = bs->drv;
    int64_t offset, length, backing_length;
    int ro;
    int64_t n;
    int ret = 0;
    uint8_t *buf = NULL;
    Error *local_err = NULL;

    if (!drv)
        return -ENOMEDIUM;

    if (!bs->backing) {
        return -ENOTSUP;
    }

    if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT_SOURCE, NULL) ||
        bdrv_op_is_blocked(bs->backing->bs, BLOCK_OP_TYPE_COMMIT_TARGET, NULL)) {
        return -EBUSY;
    }

    ro = bs->backing->bs->read_only;

    if (ro) {
        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);

    ret = blk_insert_bs(src, bs, &local_err);
    if (ret < 0) {
        error_report_err(local_err);
        goto ro_cleanup;
    }

    /* Insert commit_top block node above backing, so we can write to it */
    backing_file_bs = backing_bs(bs);

    commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, NULL, BDRV_O_RDWR,
                                         &local_err);
    if (commit_top_bs == NULL) {
        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);

    ret = blk_insert_bs(backing, backing_file_bs, &local_err);
    if (ret < 0) {
        error_report_err(local_err);
        goto ro_cleanup;
    }

    length = blk_getlength(src);
    if (length < 0) {
        ret = length;
        goto ro_cleanup;
    }

    backing_length = blk_getlength(backing);
    if (backing_length < 0) {
        ret = backing_length;
        goto ro_cleanup;
    }

    /* If our top snapshot is larger than the backing file image,
     * grow the backing file image if possible.  If not possible,
     * we must return an error */
    if (length > backing_length) {
        ret = blk_truncate(backing, length, PREALLOC_MODE_OFF, &local_err);
        if (ret < 0) {
            error_report_err(local_err);
            goto ro_cleanup;
        }
    }

    /* blk_try_blockalign() for src will choose an alignment that works for
     * backing as well, so no need to compare the alignment manually. */
    buf = blk_try_blockalign(src, COMMIT_BUF_SIZE);
    if (buf == NULL) {
        ret = -ENOMEM;
        goto ro_cleanup;
    }

    for (offset = 0; offset < length; offset += n) {
        ret = bdrv_is_allocated(bs, offset, COMMIT_BUF_SIZE, &n);
        if (ret < 0) {
            goto ro_cleanup;
        }
        if (ret) {
            ret = blk_pread(src, offset, buf, n);
            if (ret < 0) {
                goto ro_cleanup;
            }

            ret = blk_pwrite(backing, offset, buf, n, 0);
            if (ret < 0) {
                goto ro_cleanup;
            }
        }
    }

    if (drv->bdrv_make_empty) {
        ret = drv->bdrv_make_empty(bs);
        if (ret < 0) {
            goto ro_cleanup;
        }
        blk_flush(src);
    }

    /*
     * Make sure all data we wrote to the backing device is actually
     * stable on disk.
     */
    blk_flush(backing);

    ret = 0;
ro_cleanup:
    qemu_vfree(buf);

    blk_unref(backing);
    if (backing_file_bs) {
        bdrv_set_backing_hd(bs, backing_file_bs, &error_abort);
    }
    bdrv_unref(commit_top_bs);
    blk_unref(src);

    if (ro) {
        /* ignoring error return here */
        bdrv_reopen_set_read_only(bs->backing->bs, true, NULL);
    }

    return ret;
}
示例#5
0
文件: commit.c 项目: MaddTheSane/qemu
void commit_start(const char *job_id, BlockDriverState *bs,
                  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;
    BlockDriverState *iter;
    BlockDriverState *commit_top_bs = NULL;
    Error *local_err = NULL;
    int ret;

    assert(top != bs);
    if (top == base) {
        error_setg(errp, "Invalid files for merge: top and base are the same");
        return;
    }

    s = block_job_create(job_id, &commit_job_driver, NULL, bs, 0, BLK_PERM_ALL,
                         speed, creation_flags, NULL, NULL, errp);
    if (!s) {
        return;
    }

    /* convert base to r/w, if necessary */
    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;
        }
    }

    /* Insert commit_top block node above top, so we can block consistent read
     * on the backing chain below it */
    commit_top_bs = bdrv_new_open_driver(&bdrv_commit_top, filter_node_name, 0,
                                         errp);
    if (commit_top_bs == NULL) {
        goto fail;
    }
    if (!filter_node_name) {
        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);
    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. */
    assert(bdrv_chain_contains(top, base));
    for (iter = top; iter != base; iter = backing_bs(iter)) {
        /* 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. */
        ret = block_job_add_bdrv(&s->common, "intermediate node", iter, 0,
                                 BLK_PERM_WRITE_UNCHANGED | BLK_PERM_WRITE,
                                 errp);
        if (ret < 0) {
            goto fail;
        }
    }

    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
                      | BLK_PERM_WRITE
                      | BLK_PERM_RESIZE,
                      BLK_PERM_CONSISTENT_READ
                      | BLK_PERM_GRAPH_MOD
                      | BLK_PERM_WRITE_UNCHANGED);
    ret = blk_insert_bs(s->base, base, errp);
    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);
    ret = blk_insert_bs(s->top, top, errp);
    if (ret < 0) {
        goto fail;
    }

    s->backing_file_str = g_strdup(backing_file_str);
    s->on_error = on_error;

    trace_commit_start(bs, base, top, s);
    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);
    }
    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);
    }
}