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authorMing Lei <ming.lei@redhat.com>2018-08-14 23:57:49 +0800
committerJens Axboe <axboe@kernel.dk>2018-08-14 11:05:52 -0600
commitdf60f6e835f763258a06cdbb5690a2e35c1aac4e (patch)
tree2313844fbbbc0204fadbca168205b46cc619071e /block
parentb089cfd95d32638335c551651a8e00fd2c4edb0b (diff)
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')
-rw-r--r--block/blk-wbt.c6
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;