Add an API to receive a callback when a BlockDriverState is attached or detached from the block graph. This allows callers to track insert, remove, and replace operations.
Note that this API might be able to replace the blk_add_remove_bs_notifier() API if the callback checks that the root BDS is being removed and ignores all other calls. I think this is a bit messy though, so I kept blk_add_remove_bs_notifier(). Signed-off-by: Stefan Hajnoczi <[email protected]> Reviewed-by: Eric Blake <[email protected]> --- include/system/block-backend-global-state.h | 9 ++ block/block-backend.c | 44 ++++++ tests/unit/test-block-backend.c | 164 ++++++++++++++++++++ 3 files changed, 217 insertions(+) diff --git a/include/system/block-backend-global-state.h b/include/system/block-backend-global-state.h index c3849640df..e828f271ee 100644 --- a/include/system/block-backend-global-state.h +++ b/include/system/block-backend-global-state.h @@ -97,6 +97,15 @@ void blk_remove_aio_context_notifier(BlockBackend *blk, void (*detach_aio_context)(void *), void *opaque); void blk_add_remove_bs_notifier(BlockBackend *blk, Notifier *notify); + +typedef struct { + BlockBackend *blk; + BlockDriverState *bs; +} BlockBackendAttachDetachArgs; + +void blk_add_attach_notifier(BlockBackend *blk, Notifier *notify); +void blk_add_detach_notifier(BlockBackend *blk, Notifier *notify); + BlockBackendRootState *blk_get_root_state(BlockBackend *blk); void blk_update_root_state(BlockBackend *blk); bool blk_get_detect_zeroes_from_root_state(BlockBackend *blk); diff --git a/block/block-backend.c b/block/block-backend.c index f8d6ba65c1..45e31f0079 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -76,6 +76,7 @@ struct BlockBackend { /* Protected by BQL */ NotifierList remove_bs_notifiers, insert_bs_notifiers; + NotifierList attach_notifiers, detach_notifiers; QLIST_HEAD(, BlockBackendAioNotifier) aio_notifiers; int quiesce_counter; /* atomic: written under BQL, read by other threads */ @@ -280,6 +281,30 @@ static int GRAPH_RDLOCK blk_root_inactivate(BdrvChild *child) return 0; } +static void GRAPH_WRLOCK +blk_root_propagate_attach(BdrvChild *self, BdrvChild *descendant) +{ + BlockBackend *blk = self->opaque; + BlockBackendAttachDetachArgs args = { + .blk = blk, + .bs = descendant->bs, + }; + + notifier_list_notify(&blk->attach_notifiers, &args); +} + +static void GRAPH_WRLOCK +blk_root_propagate_detach(BdrvChild *self, BdrvChild *descendant) +{ + BlockBackend *blk = self->opaque; + BlockBackendAttachDetachArgs args = { + .blk = blk, + .bs = descendant->bs, + }; + + notifier_list_notify(&blk->detach_notifiers, &args); +} + static void blk_root_attach(BdrvChild *child) { BlockBackend *blk = child->opaque; @@ -333,6 +358,9 @@ static const BdrvChildClass child_root = { .activate = blk_root_activate, .inactivate = blk_root_inactivate, + .propagate_attach = blk_root_propagate_attach, + .propagate_detach = blk_root_propagate_detach, + .attach = blk_root_attach, .detach = blk_root_detach, @@ -374,6 +402,8 @@ BlockBackend *blk_new(AioContext *ctx, uint64_t perm, uint64_t shared_perm) qemu_co_queue_init(&blk->queued_requests); notifier_list_init(&blk->remove_bs_notifiers); notifier_list_init(&blk->insert_bs_notifiers); + notifier_list_init(&blk->attach_notifiers); + notifier_list_init(&blk->detach_notifiers); QLIST_INIT(&blk->aio_notifiers); QTAILQ_INSERT_TAIL(&block_backends, blk, link); @@ -492,6 +522,8 @@ static void blk_delete(BlockBackend *blk) } assert(QLIST_EMPTY(&blk->remove_bs_notifiers.notifiers)); assert(QLIST_EMPTY(&blk->insert_bs_notifiers.notifiers)); + assert(QLIST_EMPTY(&blk->attach_notifiers.notifiers)); + assert(QLIST_EMPTY(&blk->detach_notifiers.notifiers)); assert(QLIST_EMPTY(&blk->aio_notifiers)); assert(qemu_co_queue_empty(&blk->queued_requests)); qemu_mutex_destroy(&blk->queued_requests_lock); @@ -2512,6 +2544,18 @@ void blk_add_remove_bs_notifier(BlockBackend *blk, Notifier *notify) notifier_list_add(&blk->remove_bs_notifiers, notify); } +void blk_add_attach_notifier(BlockBackend *blk, Notifier *notify) +{ + GLOBAL_STATE_CODE(); + notifier_list_add(&blk->attach_notifiers, notify); +} + +void blk_add_detach_notifier(BlockBackend *blk, Notifier *notify) +{ + GLOBAL_STATE_CODE(); + notifier_list_add(&blk->detach_notifiers, notify); +} + BlockAcctStats *blk_get_stats(BlockBackend *blk) { IO_CODE(); diff --git a/tests/unit/test-block-backend.c b/tests/unit/test-block-backend.c index 4257b3f815..693383f029 100644 --- a/tests/unit/test-block-backend.c +++ b/tests/unit/test-block-backend.c @@ -24,6 +24,7 @@ #include "qemu/osdep.h" #include "block/block.h" +#include "block/block_int.h" #include "system/block-backend.h" #include "qapi/error.h" #include "qemu/main-loop.h" @@ -70,6 +71,167 @@ static void test_drain_all_aio_error(void) blk_unref(blk); } +static int bdrv_test_co_change_backing_file(BlockDriverState *bs, + const char *backing_file, + const char *backing_fmt) +{ + return 0; /* just return success so bdrv_set_backing_hd() works */ +} + +static BlockDriver bdrv_test = { + .format_name = "test", + .supports_backing = true, + .bdrv_child_perm = bdrv_default_perms, + .bdrv_co_change_backing_file = bdrv_test_co_change_backing_file, +}; + +typedef struct { + Notifier attach_notifier; + Notifier detach_notifier; + GArray *notifications; +} AttachDetach; + +typedef enum { + NOTIFY_END = 0, + NOTIFY_ATTACH, + NOTIFY_DETACH, +} NotificationType; + +typedef struct { + NotificationType type; + BlockDriverState *bs; +} Notification; + +static void attach_detach_append(AttachDetach *ad, NotificationType type, + BlockBackendAttachDetachArgs *args) +{ + Notification n = { + .type = type, + .bs = args->bs, + }; + + g_array_append_vals(ad->notifications, &n, 1); +} + +static void attach_notify(Notifier *notifier, void *data) +{ + AttachDetach *ad = container_of(notifier, AttachDetach, attach_notifier); + attach_detach_append(ad, NOTIFY_ATTACH, data); +} + +static void detach_notify(Notifier *notifier, void *data) +{ + AttachDetach *ad = container_of(notifier, AttachDetach, attach_notifier); + attach_detach_append(ad, NOTIFY_DETACH, data); +} + +static void attach_detach_init(AttachDetach *ad, BlockBackend *blk) +{ + ad->attach_notifier.notify = attach_notify; + ad->detach_notifier.notify = detach_notify; + ad->notifications = g_array_new(true, true, sizeof(Notification)); + + blk_add_attach_notifier(blk, &ad->attach_notifier); + blk_add_detach_notifier(blk, &ad->detach_notifier); +} + +static void attach_detach_cleanup(AttachDetach *ad) +{ + g_array_free(ad->notifications, true); + notifier_remove(&ad->detach_notifier); + notifier_remove(&ad->attach_notifier); +} + +/* + * Check that the expected notifications occurred. @expected is terminated by a + * NOTIFY_END element. + */ +static void attach_detach_expect(AttachDetach *ad, const Notification *expected) +{ + GArray *array = ad->notifications; + + /* The array is zero terminated so there is at least one element */ + Notification *actual = (Notification *)array->data; + + while (expected->type != NOTIFY_END) { + g_assert_cmpint(actual->type, ==, expected->type); + g_assert(actual->bs == expected->bs); + expected++; + actual++; + } + + g_assert_cmpint(actual->type, ==, NOTIFY_END); + + g_array_remove_range(array, 0, array->len); +} + +static void test_attach_detach_notifier(void) +{ + AttachDetach ad; + BlockDriverState *format; + BlockDriverState *file; + BlockDriverState *file2; + BlockBackend *blk = blk_new(qemu_get_aio_context(), + BLK_PERM_ALL, BLK_PERM_ALL); + + attach_detach_init(&ad, blk); + + format = bdrv_new_open_driver(&bdrv_test, "format", BDRV_O_RDWR, + &error_abort); + file = bdrv_new_open_driver(&bdrv_test, "file", BDRV_O_RDWR, &error_abort); + file2 = bdrv_new_open_driver(&bdrv_test, "file2", BDRV_O_RDWR, + &error_abort); + + bdrv_graph_wrlock_drained(); + bdrv_attach_child(format, file, "file", &child_of_bds, + BDRV_CHILD_PRIMARY | BDRV_CHILD_DATA, &error_abort); + bdrv_graph_wrunlock(); + + /* Insert format -> file */ + blk_insert_bs(blk, format, &error_abort); + attach_detach_expect(&ad, (Notification[]){ + (Notification){NOTIFY_ATTACH, format}, + {}, + }); + + /* Replace format -> file with file2 */ + blk_replace_bs(blk, file2, &error_abort); + attach_detach_expect(&ad, (Notification[]){ + (Notification){NOTIFY_DETACH, format}, + (Notification){NOTIFY_ATTACH, file2}, + {}, + }); + + /* Remove file2 */ + blk_remove_bs(blk); + attach_detach_expect(&ad, (Notification[]){ + (Notification){NOTIFY_DETACH, file2}, + {}, + }); + + /* These BDSes were unrefed so we need new instances */ + file = bdrv_new_open_driver(&bdrv_test, "file", BDRV_O_RDWR, &error_abort); + file2 = bdrv_new_open_driver(&bdrv_test, "file2", BDRV_O_RDWR, + &error_abort); + + /* Replace a non-root node */ + bdrv_graph_wrlock_drained(); + bdrv_attach_child(format, file, "file", &child_of_bds, + BDRV_CHILD_PRIMARY | BDRV_CHILD_DATA, &error_abort); + bdrv_replace_node(file, file2, &error_abort); + bdrv_graph_wrunlock(); + attach_detach_expect(&ad, (Notification[]){ + (Notification){NOTIFY_ATTACH, file}, + (Notification){NOTIFY_DETACH, file}, + (Notification){NOTIFY_ATTACH, file2}, + {}, + }); + + attach_detach_cleanup(&ad); + blk_unref(blk); + bdrv_unref(format); +} + int main(int argc, char **argv) { bdrv_init(); @@ -80,6 +242,8 @@ int main(int argc, char **argv) g_test_add_func("/block-backend/drain_aio_error", test_drain_aio_error); g_test_add_func("/block-backend/drain_all_aio_error", test_drain_all_aio_error); + g_test_add_func("/block-backend/attach_detach_notifier", + test_attach_detach_notifier); return g_test_run(); } -- 2.51.0
