On Fri, 19 Oct 2018 18:21:00 -0400, Dennis Zhou said: > Do you by chance run any encryption or anything on top of your hard > drive or ssd? ext4 on an LVM LV that's part of a PV that's inside a cryptLUKS partition on a hard drive.. So lots of nested levels there. > I thought of another issue that may explain what's going on. It has to > do with how a bio can go through make_request() several times. However, > I do association on the first entry, but subsequent requests may go to > separate queues. Therefore association and the blk_get_rl() returns the > wrong request_list. It may be that a particular blkg doesn't have a > fully initialized request_list. > Thanks for being patient with me. Would you be able to try the following > on Jens' for-4.20/block branch? His tree is available here: > https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git No problem. I've managed to trip over issues that took a *lot* longer to resolve (I think back around 2.5.47 or so, the PCMCIA slot in my Dell Latitude kept finding different ways to explode the kernel for close to 8-9 months...) I checked, and linux-next was all of 1 commit behind jens' for-4.20 tree, so I applied it to that (I had a linux-next tree that works, but I'm a git idiot so figuring out how to graft that tree on was going to take a while...) Result: Script started on 2018-10-19 22:29:32-04:00 [root@turing-police x86_64]# uname -a Linux turing-police.cc.vt.edu 4.19.0-rc8-next-20181019-dirty #641 SMP PREEMPT Fri Oct 19 21:18:19 EDT 2018 x86_64 x86_64 x86_64 GNU/Linux [root@turing-police x86_64]# rpm -Uvh --force dracut-049-4.git20181010.fc30.x86_64.rpm Verifying... ################################# [100%] warning: Unable to get systemd shutdown inhibition lock: Failed to connect to socket /run/dbus/system_bus_socket: No such file or directory Preparing... ################################# [100%] Updating / installing... 1:dracut-049-4.git20181010.fc30 ################################# [100%] [root@turing-police x86_64]# exit exit Script done on 2018-10-19 22:29:59-04:00 System stable, RPM works, dnf works, some good-sized compiles worked. Looks like it's time to commit that, and add these: Reported-by: Valdis Kletnieks <valdis.kletnieks@xxxxxx> Tested-by: Valdis Kletnieks <valdis.kletnieks@xxxxxx> :) > --- > block/bio.c | 20 ++++++++++++++++++++ > block/blk-core.c | 1 + > include/linux/bio.h | 3 +++ > 3 files changed, 24 insertions(+) > > diff --git a/block/bio.c b/block/bio.c > index 17a8b0aa7050..bbfeb4ee2892 100644 > --- a/block/bio.c > +++ b/block/bio.c > @@ -2083,6 +2083,26 @@ int bio_associate_create_blkg(struct request_queue *q, struct bio *bio) > return ret; > } > > +/** > + * bio_reassociate_blkg - reassociate a bio with a blkg from q > + * @q: request_queue where bio is going > + * @bio: target bio > + * > + * When submitting a bio, multiple recursive calls to make_request() may occur. > + * This causes the initial associate done in blkcg_bio_issue_check() to be > + * incorrect and reference the prior request_queue. This performs reassociation > + * when this situation happens. > + */ > +int bio_reassociate_blkg(struct request_queue *q, struct bio *bio) > +{ > + if (bio->bi_blkg) { > + blkg_put(bio->bi_blkg); > + bio->bi_blkg = NULL; > + } > + > + return bio_associate_create_blkg(q, bio); > +} > + > /** > * bio_disassociate_task - undo bio_associate_current() > * @bio: target bio > diff --git a/block/blk-core.c b/block/blk-core.c > index cdfabc5646da..3ed60723e242 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -2433,6 +2433,7 @@ blk_qc_t generic_make_request(struct bio *bio) > if (q) > blk_queue_exit(q); > q = bio->bi_disk->queue; > + bio_reassociate_blkg(q, bio); > flags = 0; > if (bio->bi_opf & REQ_NOWAIT) > flags = BLK_MQ_REQ_NOWAIT; > diff --git a/include/linux/bio.h b/include/linux/bio.h > index f447b0ebb288..b47c7f716731 100644 > --- a/include/linux/bio.h > +++ b/include/linux/bio.h > @@ -514,6 +514,7 @@ int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg); > int bio_associate_blkg_from_css(struct bio *bio, > struct cgroup_subsys_state *css); > int bio_associate_create_blkg(struct request_queue *q, struct bio *bio); > +int bio_reassociate_blkg(struct request_queue *q, struct bio *bio); > void bio_disassociate_task(struct bio *bio); > void bio_clone_blkg_association(struct bio *dst, struct bio *src); > #else /* CONFIG_BLK_CGROUP */ > @@ -522,6 +523,8 @@ static inline int bio_associate_blkg_from_css(struct bio *bio, > { return 0; } > static inline int bio_associate_create_blkg(struct request_queue *q, > struct bio *bio) { return 0; } > +static inline int bio_reassociate_blkg(struct request_queue *q, struct bio *bio) > +{ return 0; } > static inline void bio_disassociate_task(struct bio *bio) { } > static inline void bio_clone_blkg_association(struct bio *dst, > struct bio *src) { } > -- > 2.17.1 >
Attachment:
pgpZGSJHYuWGf.pgp
Description: PGP signature
