[dm-devel] [PATCH] block: make discard killable

[Mikulas Patocka]

On Fri, 6 Jul 2018, Jens Axboe wrote:

> On 7/3/18 11:35 AM, Mikulas Patocka wrote:
> > Discarding can take very long time for some device mapper targets, this
> > patch makes it possible to kill a process that issues the BLKDISCARD
> > ioctl.
> > 
> > Note that some filesystems call blkdev_issue_discard or
> > __blkdev_issue_discard directly, they may not be prepared to handle the
> > failure, so this patch introduces a flag BLKDEV_DISCARD_KILLABLE that is
> > only set when the discard is initiated by an ioctl.
> 
> This might be cleaner as a regular request flag, since killable can
> apply to other types of IO as well - like readahead.
> 
> -- 
> Jens Axboe

blkdev_issue_discard and __blkdev_issue_discard doesn't take flags for the 
request - it has a "flags" argument which could only contain one flag - 
BLKDEV_DISCARD_SECURE.

Do you want to copy the "flags" argument from blkdev_issue_discard to the 
bio and check the bio flag in generic_make_request?

Mikulas