On Mon, Mar 10, 2014 at 03:25:59PM +0800, Fam Zheng wrote:
> This drops BlockDriverState.in_use with op_blockers:
>
> - Call bdrv_op_block_all in place of bdrv_set_in_use(bs, 1).
> - Call bdrv_op_unblock_all in place of bdrv_set_in_use(bs, 0).
> - Check bdrv_op_is_blocked() in place of bdrv_in_use(bs).
> The specific types are used, e.g. in place of starting block backup,
> bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP, ...).
> - Check bdrv_op_blocker_is_empty() in place of assert(!bs->in_use).
>
> Note: there is only bdrv_op_block_all and bdrv_op_unblock_all callers at
> this moment. So although the checks are specific to op types, this
> changes can still be seen as identical logic with previously with
> in_use. The difference is error message are improved because of blocker
> error info.
>
> Signed-off-by: Fam Zheng <f...@redhat.com>
> Signed-off-by: Markus Armbruster <arm...@redhat.com>
> ---
> block-migration.c | 7 +++++--
> block.c | 24 +++++++-----------------
> blockdev.c | 19 +++++++++----------
> blockjob.c | 14 +++++++++-----
> hw/block/dataplane/virtio-blk.c | 19 ++++++++++++-------
> include/block/block.h | 2 --
> include/block/block_int.h | 1 -
> include/block/blockjob.h | 3 +++
> 8 files changed, 45 insertions(+), 44 deletions(-)
>
> diff --git a/block-migration.c b/block-migration.c
> index 897fdba..bf9a25f 100644
> --- a/block-migration.c
> +++ b/block-migration.c
> @@ -59,6 +59,7 @@ typedef struct BlkMigDevState {
> unsigned long *aio_bitmap;
> int64_t completed_sectors;
> BdrvDirtyBitmap *dirty_bitmap;
> + Error *blocker;
> } BlkMigDevState;
>
> typedef struct BlkMigBlock {
> @@ -346,7 +347,8 @@ static void init_blk_migration_it(void *opaque,
> BlockDriverState *bs)
> bmds->completed_sectors = 0;
> bmds->shared_base = block_mig_state.shared_base;
> alloc_aio_bitmap(bmds);
> - bdrv_set_in_use(bs, 1);
> + error_setg(&bmds->blocker, "block device is in use by migration");
> + bdrv_op_block_all(bs, bmds->blocker);
> bdrv_ref(bs);
>
> block_mig_state.total_sector_sum += sectors;
> @@ -584,7 +586,8 @@ static void blk_mig_cleanup(void)
> blk_mig_lock();
> while ((bmds = QSIMPLEQ_FIRST(&block_mig_state.bmds_list)) != NULL) {
> QSIMPLEQ_REMOVE_HEAD(&block_mig_state.bmds_list, entry);
> - bdrv_set_in_use(bmds->bs, 0);
> + bdrv_op_unblock_all(bmds->bs, bmds->blocker);
> + error_free(bmds->blocker);
> bdrv_unref(bmds->bs);
> g_free(bmds->aio_bitmap);
> g_free(bmds);
> diff --git a/block.c b/block.c
> index 56a4433..c79d5dc 100644
> --- a/block.c
> +++ b/block.c
> @@ -1850,7 +1850,6 @@ static void bdrv_move_feature_fields(BlockDriverState
> *bs_dest,
> bs_dest->refcnt = bs_src->refcnt;
>
> /* job */
> - bs_dest->in_use = bs_src->in_use;
[1]
> bs_dest->job = bs_src->job;
>
> /* keep the same entry in bdrv_states */
> @@ -1893,7 +1892,7 @@ void bdrv_swap(BlockDriverState *bs_new,
> BlockDriverState *bs_old)
> assert(QLIST_EMPTY(&bs_new->dirty_bitmaps));
> assert(bs_new->job == NULL);
> assert(bs_new->dev == NULL);
> - assert(bs_new->in_use == 0);
> + assert(bdrv_op_blocker_is_empty(bs_new));
Since we won't move the blocker via move_feature_fields() like we
did with in_use, do you think we should also assert on bs_old blocker
fields as well? I.e.:
assert(bdrv_op_blocker_is_empty(bs_old));
Or, alternatively, to keep the same behavior as in_use, preserve the
overlay bs blocker via bdrv_move_feature_field at [1] (see above)?
> assert(bs_new->io_limits_enabled == false);
> assert(!throttle_have_timer(&bs_new->throttle_state));
>
> @@ -1912,7 +1911,7 @@ void bdrv_swap(BlockDriverState *bs_new,
> BlockDriverState *bs_old)
> /* Check a few fields that should remain attached to the device */
> assert(bs_new->dev == NULL);
> assert(bs_new->job == NULL);
> - assert(bs_new->in_use == 0);
> + assert(bdrv_op_blocker_is_empty(bs_new));
> assert(bs_new->io_limits_enabled == false);
> assert(!throttle_have_timer(&bs_new->throttle_state));
>
> @@ -1957,7 +1956,7 @@ static void bdrv_delete(BlockDriverState *bs)
> {
> assert(!bs->dev);
> assert(!bs->job);
> - assert(!bs->in_use);
> + assert(bdrv_op_blocker_is_empty(bs));
> assert(!bs->refcnt);
> assert(QLIST_EMPTY(&bs->dirty_bitmaps));
>
> @@ -2139,7 +2138,8 @@ int bdrv_commit(BlockDriverState *bs)
> return -ENOTSUP;
> }
>
> - if (bdrv_in_use(bs) || bdrv_in_use(bs->backing_hd)) {
> + if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_COMMIT, NULL) ||
> + bdrv_op_is_blocked(bs->backing_hd, BLOCK_OP_TYPE_COMMIT, NULL)) {
> return -EBUSY;
> }
>
> @@ -3374,8 +3374,9 @@ int bdrv_truncate(BlockDriverState *bs, int64_t offset)
> return -ENOTSUP;
> if (bs->read_only)
> return -EACCES;
> - if (bdrv_in_use(bs))
> + if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_RESIZE, NULL)) {
> return -EBUSY;
> + }
> ret = drv->bdrv_truncate(bs, offset);
> if (ret == 0) {
> ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
> @@ -5226,17 +5227,6 @@ bool bdrv_op_blocker_is_empty(BlockDriverState *bs)
> return true;
> }
>
> -void bdrv_set_in_use(BlockDriverState *bs, int in_use)
> -{
> - assert(bs->in_use != in_use);
> - bs->in_use = in_use;
> -}
> -
> -int bdrv_in_use(BlockDriverState *bs)
> -{
> - return bs->in_use;
> -}
> -
> void bdrv_iostatus_enable(BlockDriverState *bs)
> {
> bs->iostatus_enabled = true;
> diff --git a/blockdev.c b/blockdev.c
> index c3422a1..593925e 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -1293,8 +1293,8 @@ static void
> external_snapshot_prepare(BlkTransactionState *common,
> return;
> }
>
> - if (bdrv_in_use(state->old_bs)) {
> - error_set(errp, QERR_DEVICE_IN_USE, device);
> + if (bdrv_op_is_blocked(state->old_bs,
> + BLOCK_OP_TYPE_EXTERNAL_SNAPSHOT, errp)) {
> return;
> }
>
> @@ -1516,8 +1516,7 @@ exit:
>
> static void eject_device(BlockDriverState *bs, int force, Error **errp)
> {
> - if (bdrv_in_use(bs)) {
> - error_set(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
> + if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_EJECT, errp)) {
> return;
> }
> if (!bdrv_dev_has_removable_media(bs)) {
> @@ -1717,14 +1716,16 @@ int do_drive_del(Monitor *mon, const QDict *qdict,
> QObject **ret_data)
> {
> const char *id = qdict_get_str(qdict, "id");
> BlockDriverState *bs;
> + Error *local_err = NULL;
>
> bs = bdrv_find(id);
> if (!bs) {
> qerror_report(QERR_DEVICE_NOT_FOUND, id);
> return -1;
> }
> - if (bdrv_in_use(bs)) {
> - qerror_report(QERR_DEVICE_IN_USE, id);
> + if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_DRIVE_DEL, &local_err)) {
> + error_report("%s", error_get_pretty(local_err));
> + error_free(local_err);
> return -1;
> }
>
> @@ -1976,8 +1977,7 @@ void qmp_drive_backup(const char *device, const char
> *target,
> }
> }
>
> - if (bdrv_in_use(bs)) {
> - error_set(errp, QERR_DEVICE_IN_USE, device);
> + if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_BACKUP_SOURCE, errp)) {
> return;
> }
>
> @@ -2110,8 +2110,7 @@ void qmp_drive_mirror(const char *device, const char
> *target,
> }
> }
>
> - if (bdrv_in_use(bs)) {
> - error_set(errp, QERR_DEVICE_IN_USE, device);
> + if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_MIRROR, errp)) {
> return;
> }
>
> diff --git a/blockjob.c b/blockjob.c
> index b3ce14c..f643a78 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -41,14 +41,16 @@ void *block_job_create(const BlockJobDriver *driver,
> BlockDriverState *bs,
> {
> BlockJob *job;
>
> - if (bs->job || bdrv_in_use(bs)) {
> + if (bs->job || !bdrv_op_blocker_is_empty(bs)) {
> error_set(errp, QERR_DEVICE_IN_USE, bdrv_get_device_name(bs));
> return NULL;
> }
> bdrv_ref(bs);
> - bdrv_set_in_use(bs, 1);
> -
> job = g_malloc0(driver->instance_size);
> + error_setg(&job->blocker, "block device is in use by block job: %s",
> + BlockJobType_lookup[driver->job_type]);
> + bdrv_op_block_all(bs, job->blocker);
> +
> job->driver = driver;
> job->bs = bs;
> job->cb = cb;
> @@ -63,8 +65,9 @@ void *block_job_create(const BlockJobDriver *driver,
> BlockDriverState *bs,
> block_job_set_speed(job, speed, &local_err);
> if (local_err) {
> bs->job = NULL;
> + bdrv_op_unblock_all(bs, job->blocker);
> + error_free(job->blocker);
> g_free(job);
> - bdrv_set_in_use(bs, 0);
> error_propagate(errp, local_err);
> return NULL;
> }
> @@ -79,8 +82,9 @@ void block_job_completed(BlockJob *job, int ret)
> assert(bs->job == job);
> job->cb(job->opaque, ret);
> bs->job = NULL;
> + bdrv_op_unblock_all(bs, job->blocker);
> + error_free(job->blocker);
> g_free(job);
> - bdrv_set_in_use(bs, 0);
> }
>
> void block_job_set_speed(BlockJob *job, int64_t speed, Error **errp)
> diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
> index 2237edb..cee0aa5 100644
> --- a/hw/block/dataplane/virtio-blk.c
> +++ b/hw/block/dataplane/virtio-blk.c
> @@ -69,6 +69,9 @@ struct VirtIOBlockDataPlane {
> queue */
>
> unsigned int num_reqs;
> +
> + /* Operation blocker on BDS */
> + Error *blocker;
> };
>
> /* Raise an interrupt to signal guest, if necessary */
> @@ -368,6 +371,7 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev,
> VirtIOBlkConf *blk,
> {
> VirtIOBlockDataPlane *s;
> int fd;
> + Error *local_err = NULL;
>
> *dataplane = NULL;
>
> @@ -390,9 +394,10 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev,
> VirtIOBlkConf *blk,
> /* If dataplane is (re-)enabled while the guest is running there could be
> * block jobs that can conflict.
> */
> - if (bdrv_in_use(blk->conf.bs)) {
> - error_setg(errp,
> - "cannot start dataplane thread while device is in use");
> + if (bdrv_op_is_blocked(blk->conf.bs, BLOCK_OP_TYPE_DATAPLANE,
> &local_err)) {
> + error_report("cannot start dataplane thread: %s",
> + error_get_pretty(local_err));
> + error_free(local_err);
> return;
> }
>
> @@ -407,9 +412,8 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev,
> VirtIOBlkConf *blk,
> s->vdev = vdev;
> s->fd = fd;
> s->blk = blk;
> -
> - /* Prevent block operations that conflict with data plane thread */
> - bdrv_set_in_use(blk->conf.bs, 1);
> + error_setg(&s->blocker, "block device is in use by data plane");
> + bdrv_op_block_all(blk->conf.bs, s->blocker);
>
> *dataplane = s;
> }
> @@ -421,7 +425,8 @@ void virtio_blk_data_plane_destroy(VirtIOBlockDataPlane
> *s)
> }
>
> virtio_blk_data_plane_stop(s);
> - bdrv_set_in_use(s->blk->conf.bs, 0);
> + bdrv_op_unblock_all(s->blk->conf.bs, s->blocker);
> + error_free(s->blocker);
> g_free(s);
> }
>
> diff --git a/include/block/block.h b/include/block/block.h
> index 4874e2a..a46f70a 100644
> --- a/include/block/block.h
> +++ b/include/block/block.h
> @@ -471,8 +471,6 @@ void bdrv_disable_copy_on_read(BlockDriverState *bs);
>
> void bdrv_ref(BlockDriverState *bs);
> void bdrv_unref(BlockDriverState *bs);
> -void bdrv_set_in_use(BlockDriverState *bs, int in_use);
> -int bdrv_in_use(BlockDriverState *bs);
>
> bool bdrv_op_is_blocked(BlockDriverState *bs, BlockOpType op, Error **errp);
> void bdrv_op_block(BlockDriverState *bs, BlockOpType op, Error *reason);
> diff --git a/include/block/block_int.h b/include/block/block_int.h
> index 4e558d0..1d3f76f 100644
> --- a/include/block/block_int.h
> +++ b/include/block/block_int.h
> @@ -359,7 +359,6 @@ struct BlockDriverState {
> QTAILQ_ENTRY(BlockDriverState) device_list;
> QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps;
> int refcnt;
> - int in_use; /* users other than guest access, eg. block migration */
>
> QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
>
> diff --git a/include/block/blockjob.h b/include/block/blockjob.h
> index d76de62..c0a7875 100644
> --- a/include/block/blockjob.h
> +++ b/include/block/blockjob.h
> @@ -106,6 +106,9 @@ struct BlockJob {
> /** The completion function that will be called when the job completes.
> */
> BlockDriverCompletionFunc *cb;
>
> + /** Block other operations when block job is running */
> + Error *blocker;
> +
> /** The opaque value that is passed to the completion function. */
> void *opaque;
> };
> --
> 1.9.0
>
>
