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For leaf cgroups this tree is empty, so the > timer fires and exits without dispatching the throttled bio. > > The throttled bio sits in the parent's pending_tree with disptime set > to jiffies (THROTL_TG_CANCELING zeroes all dispatch times), but the > parent's timer is never explicitly rescheduled. The bio only gets > dispatched when the parent timer eventually fires at its previously > scheduled expiry. > > Fix by calling throtl_schedule_next_dispatch(sq->parent_sq, true) > instead, matching what tg_set_limit() already does. This forces the > parent's dispatch cycle to run immediately and flush all canceling > bios without waiting for a stale timer. > > For the device deletion path (blk_throtl_cancel_bios), directly > complete throttled bios with EIO via bio_io_error() instead of > dispatching them through the timer -> work -> submission chain. > This avoids a race with the SCSI state machine where bios can reach > the SCSI layer while the device is in SDEV_CANCEL state, causing > ENODEV instead of the expected EIO. > > Reported-by: Shin'ichiro Kawasaki I reported that v1 patch fails with the blktests test case throtl/004, but I did not report the problem that this patch addresses. Then I don't think this Reported-by tag is valid. Please drop it. I confirmed that the recent blktess CI test run with this v2 patch did not fail at throtl/004. Thanks to your action for the failure.