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Date: Wed, 3 Aug 2016 19:30:29 -0500 From: Shaun Tancheff <shaun.tancheff@...gate.com> To: Mike Christie <mchristi@...hat.com> Cc: Ross Zwisler <zwisler@...il.com>, Ross Zwisler <ross.zwisler@...ux.intel.com>, Dave Chinner <david@...morbit.com>, Jens Axboe <axboe@...com>, linux-f2fs-devel@...ts.sourceforge.net, linux-ext4 <linux-ext4@...r.kernel.org>, konrad.wilk@...cle.com, drbd-dev@...ts.linbit.com, philipp.reisner@...bit.com, lars.ellenberg@...bit.com, linux-raid@...r.kernel.org, dm-devel@...hat.com, linux-fsdevel <linux-fsdevel@...r.kernel.org>, linux-bcache@...r.kernel.org, linux-block@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>, linux-scsi@...r.kernel.org, linux-mtd@...ts.infradead.org, target-devel@...r.kernel.org, linux-btrfs@...r.kernel.org, osd-dev@...n-osd.org, XFS Developers <xfs@....sgi.com>, ocfs2-devel@....oracle.com Subject: Re: [PATCH 37/45] drivers: use req op accessor On Wed, Aug 3, 2016 at 6:47 PM, Mike Christie <mchristi@...hat.com> wrote: > On 08/03/2016 05:33 PM, Ross Zwisler wrote: >> On Sun, Jun 5, 2016 at 1:32 PM, <mchristi@...hat.com> wrote: >>> From: Mike Christie <mchristi@...hat.com> >>> >>> The req operation REQ_OP is separated from the rq_flag_bits >>> definition. This converts the block layer drivers to >>> use req_op to get the op from the request struct. >>> >>> Signed-off-by: Mike Christie <mchristi@...hat.com> >>> --- >>> drivers/block/loop.c | 6 +++--- >>> drivers/block/mtip32xx/mtip32xx.c | 2 +- >>> drivers/block/nbd.c | 2 +- >>> drivers/block/rbd.c | 4 ++-- >>> drivers/block/xen-blkfront.c | 8 +++++--- >>> drivers/ide/ide-floppy.c | 2 +- >>> drivers/md/dm.c | 2 +- >>> drivers/mmc/card/block.c | 7 +++---- >>> drivers/mmc/card/queue.c | 6 ++---- >> >> Dave Chinner reported a deadlock with XFS + DAX, which I reproduced >> and bisected to this commit: >> >> commit c2df40dfb8c015211ec55f4b1dd0587f875c7b34 >> Author: Mike Christie <mchristi@...hat.com> >> Date: Sun Jun 5 14:32:17 2016 -0500 >> drivers: use req op accessor >> >> Here are the steps to reproduce the deadlock with a BRD ramdisk: >> >> mkfs.xfs -f /dev/ram0 >> mount -o dax /dev/ram0 /mnt/scratch > > When using ramdisks, we need the attached patch like in your other bug > report. I think it will fix some hangs people are seeing. > > I do not think that it should cause the failure to run issue you saw > when doing generic/008 and ext2. > I think the translation in loop.c is suspicious here: "if use DIO && not (a flush_flag or discard_flag)" should translate to: "if use DIO && not ((a flush_flag) || op == discard)" But in the patch I read: "if use DIO && ((not a flush_flag) || op == discard) Which would have DIO && discards follow the AIO path? So I would humbly suggest something like the following (on top of commit c2df40dfb8c015211ec55f4b1dd0587f875c7b34): [Please excuse the messed up patch format ... gmail eats tabs] diff --git a/drivers/block/loop.c b/drivers/block/loop.c index b9b737c..0754d83 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1659,8 +1659,9 @@ static int loop_queue_rq(struct blk_mq_hw_ctx *hctx, if (lo->lo_state != Lo_bound) return -EIO; - if (lo->use_dio && (!(cmd->rq->cmd_flags & REQ_FLUSH) || - req_op(cmd->rq) == REQ_OP_DISCARD)) + if (lo->use_dio && !( + (cmd->rq->cmd_flags & REQ_FLUSH) || + req_op(cmd->rq) == REQ_OP_DISCARD)) cmd->use_aio = true; else cmd->use_aio = false; -- Shaun Tancheff -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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