• Ilya Dryomov's avatar
    block: get rid of blk_integrity_revalidate() · 19b7ccf8
    Ilya Dryomov authored
    Commit 25520d55 ("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: 25520d55 ("block: Inline blk_integrity in struct gendisk")
    Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
    Cc: Christoph Hellwig <hch@lst.de>
    Cc: Mike Snitzer <snitzer@redhat.com>
    Cc: stable@vger.kernel.org # 4.4+, needs backporting
    Tested-by: default avatarDan Williams <dan.j.williams@intel.com>
    Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
    Signed-off-by: default avatarJens Axboe <axboe@fb.com>
    19b7ccf8
genhd.h 22.4 KB