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| author | Ming Lei <ming.lei@redhat.com> | 2018-08-14 23:57:49 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-08-14 11:05:52 -0600 |
| commit | df60f6e835f763258a06cdbb5690a2e35c1aac4e (patch) | |
| tree | 2313844fbbbc0204fadbca168205b46cc619071e /block/blk-wbt.c | |
| parent | b089cfd95d32638335c551651a8e00fd2c4edb0b (diff) | |
| download | lwn-df60f6e835f763258a06cdbb5690a2e35c1aac4e.tar.gz lwn-df60f6e835f763258a06cdbb5690a2e35c1aac4e.zip | |
blk-wbt: fix IO hang in wbt_wait()
On wbt invariant is that if one IO is tracked via WBT_TRACKED, rqw->inflight
should be updated for tracking this IO.
But commit c1c80384c8f ("block: remove external dependency on wbt_flags")
forgets to remove the early handling of !rwb_enabled(rwb) inside wbt_wait(),
then the inflight counter may not be increased in wbt_wait(), but decreased
in wbt_done() for this kind of IO, so this counter may become negative, then
wbt_wait() may wait forever.
This patch fixes the report in the following link:
https://marc.info/?l=linux-block&m=153221542021033&w=2
Fixes: c1c80384c8f ("block: remove external dependency on wbt_flags")
Cc: Josef Bacik <jbacik@fb.com>
Reported-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-wbt.c')
| -rw-r--r-- | block/blk-wbt.c | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/block/blk-wbt.c b/block/blk-wbt.c index 1d94a20374fc..bb93c7c2b182 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -576,12 +576,8 @@ static void wbt_wait(struct rq_qos *rqos, struct bio *bio, spinlock_t *lock) struct rq_wb *rwb = RQWB(rqos); enum wbt_flags flags; - if (!rwb_enabled(rwb)) - return; - flags = bio_to_wbt_flags(rwb, bio); - - if (!wbt_should_throttle(rwb, bio)) { + if (!(flags & WBT_TRACKED)) { if (flags & WBT_READ) wb_timestamp(rwb, &rwb->last_issue); return; |