int coroutine_fn bdrv_co_pdiscard(BlockDriverState *bs, int64_t offset, int count) { BdrvTrackedRequest req; int max_pdiscard, ret; int head, align; if (!bs->drv) { return -ENOMEDIUM; } ret = bdrv_check_byte_request(bs, offset, count); if (ret < 0) { return ret; } else if (bs->read_only) { return -EPERM; } assert(!(bs->open_flags & BDRV_O_INACTIVE)); /* Do nothing if disabled. */ if (!(bs->open_flags & BDRV_O_UNMAP)) { return 0; } if (!bs->drv->bdrv_co_pdiscard && !bs->drv->bdrv_aio_pdiscard) { return 0; } /* Discard is advisory, so ignore any unaligned head or tail */ align = MAX(bs->bl.pdiscard_alignment, bs->bl.request_alignment); assert(align % bs->bl.request_alignment == 0); head = offset % align; if (head) { head = MIN(count, align - head); count -= head; offset += head; } count = QEMU_ALIGN_DOWN(count, align); if (!count) { return 0; } bdrv_inc_in_flight(bs); tracked_request_begin(&req, bs, offset, count, BDRV_TRACKED_DISCARD); ret = notifier_with_return_list_notify(&bs->before_write_notifiers, &req); if (ret < 0) { goto out; } max_pdiscard = QEMU_ALIGN_DOWN(MIN_NON_ZERO(bs->bl.max_pdiscard, INT_MAX), align); assert(max_pdiscard); while (count > 0) { int ret; int num = MIN(count, max_pdiscard); if (bs->drv->bdrv_co_pdiscard) { ret = bs->drv->bdrv_co_pdiscard(bs, offset, num); } else { BlockAIOCB *acb; CoroutineIOCompletion co = { .coroutine = qemu_coroutine_self(), }; acb = bs->drv->bdrv_aio_pdiscard(bs, offset, num, bdrv_co_io_em_complete, &co); if (acb == NULL) { ret = -EIO; goto out; } else { qemu_coroutine_yield(); ret = co.ret; } } if (ret && ret != -ENOTSUP) { goto out; } offset += num; count -= num; } ret = 0; out: ++bs->write_gen; bdrv_set_dirty(bs, req.offset >> BDRV_SECTOR_BITS, req.bytes >> BDRV_SECTOR_BITS); tracked_request_end(&req); bdrv_dec_in_flight(bs); return ret; }