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block: Replace in_use with operation blocker 

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, ...).

    There is one exception in block_job_create, where
    bdrv_op_blocker_is_empty() is used, because we don't know the operation
    type here. This doesn't matter because in a few commits away we will drop
    the check and move it to callers that _do_ know the type.

  - 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 <famz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Fam Zheng 2014-05-23 21:29:43 +08:00 committed by Stefan Hajnoczi
parent fbe40ff780
commit 3718d8ab65
8 changed files with 45 additions and 43 deletions
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7
block-migration.c
View File

@ -59,6 +59,7 @@ typedef struct BlkMigDevState {
unsigned long *aio_bitmap;
int64_t completed_sectors;
BdrvDirtyBitmap *dirty_bitmap;
Error *blocker;
} BlkMigDevState;
typedef struct BlkMigBlock {
@ -361,7 +362,8 @@ 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;
@ -599,7 +601,8 @@ 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);

24
block.c
View File

@ -1949,7 +1949,6 @@ static void bdrv_move_feature_fields(BlockDriverState *bs_dest,
bs_dest->refcnt = bs_src->refcnt;
/* job */
bs_dest->in_use = bs_src->in_use;
bs_dest->job = bs_src->job;
/* keep the same entry in bdrv_states */
@ -1992,7 +1991,7 @@ 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));
assert(bs_new->io_limits_enabled == false);
assert(!throttle_have_timer(&bs_new->throttle_state));
@ -2011,7 +2010,7 @@ 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));
@ -2056,7 +2055,7 @@ 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));
@ -2238,7 +2237,8 @@ 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;
}
@ -3500,8 +3500,9 @@ 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);
@ -5401,17 +5402,6 @@ 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;

19
blockdev.c
View File

@ -1334,8 +1334,8 @@ 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;
}
@ -1557,8 +1557,7 @@ 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)) {
@ -1760,14 +1759,16 @@ 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;
}
@ -2023,8 +2024,7 @@ 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;
}
@ -2157,8 +2157,7 @@ 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;
}

14
blockjob.c
View File

@ -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)

18
hw/block/dataplane/virtio-blk.c
View File

@ -70,6 +70,9 @@ struct VirtIOBlockDataPlane {
queue */
unsigned int num_reqs;
/* Operation blocker on BDS */
Error *blocker;
};
/* Raise an interrupt to signal guest, if necessary */
@ -350,6 +353,7 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *blk,
{
VirtIOBlockDataPlane *s;
int fd;
Error *local_err = NULL;
*dataplane = NULL;
@ -372,9 +376,10 @@ 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;
}
@ -406,8 +411,8 @@ void virtio_blk_data_plane_create(VirtIODevice *vdev, VirtIOBlkConf *blk,
}
s->ctx = iothread_get_aio_context(s->iothread);
/* 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;
}
@ -420,7 +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);
object_unref(OBJECT(s->iothread));
g_free(s);
}

2
include/block/block.h
View File

@ -472,8 +472,6 @@ 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);

1
include/block/block_int.h
View File

@ -358,7 +358,6 @@ 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;

3
include/block/blockjob.h
View File

@ -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;
};