On Thu, May 11, 2017 at 12:01:29PM +0200, 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.
>
> Fixes: 25520d55cdb6 ("block: Inline blk_integrity in struct gendisk")
> Cc: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx # 4.4+, needs backporting
> Tested-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx>
> Signed-off-by: Jens Axboe <axboe@xxxxxx>
> [idryomov@xxxxxxxxx: backport to < 4.11: bdi is embedded in queue]
> ---
> block/blk-integrity.c | 19 ++-----------------
> block/partition-generic.c | 1 -
> fs/block_dev.c | 1 -
> include/linux/genhd.h | 2 --
> 4 files changed, 2 insertions(+), 21 deletions(-)
Now queued up, thanks for the backport!
greg k-h