On 04/18/2017 10:43 AM, Ilya Dryomov wrote:
> Commit 25520d55cdb6 ("block: Inline blk_integrity in struct gendisk")
> introduced blk_integrity_revalidate(), which seems to assume ownership
> of the stable pages flag and unilaterally clears it if no blk_integrity
> profile is registered:
>
> if (bi->profile)
> disk->queue->backing_dev_info->capabilities |=
> BDI_CAP_STABLE_WRITES;
> else
> disk->queue->backing_dev_info->capabilities &=
> ~BDI_CAP_STABLE_WRITES;
>
> It's called from revalidate_disk() and rescan_partitions(), making it
> impossible to enable stable pages for drivers that support partitions
> and don't use blk_integrity: while the call in revalidate_disk() can be
> trivially worked around (see zram, which doesn't support partitions and
> hence gets away with zram_revalidate_disk()), rescan_partitions() can
> be triggered from userspace at any time. This breaks rbd, where the
> ceph messenger is responsible for generating/verifying CRCs.
>
> Since blk_integrity_{un,}register() "must" be used for (un)registering
> the integrity profile with the block layer, move BDI_CAP_STABLE_WRITES
> setting there. This way drivers that call blk_integrity_register() and
> use integrity infrastructure won't interfere with drivers that don't
> but still want stable pages.
Applied, thanks.
--
Jens Axboe
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