• Martin K. Petersen's avatar
    block: Allow devices to indicate whether discarded blocks are zeroed · 98262f27
    Martin K. Petersen authored
    The discard ioctl is used by mkfs utilities to clear a block device
    prior to putting metadata down.  However, not all devices return zeroed
    blocks after a discard.  Some drives return stale data, potentially
    containing old superblocks.  It is therefore important to know whether
    discarded blocks are properly zeroed.
    Both ATA and SCSI drives have configuration bits that indicate whether
    zeroes are returned after a discard operation.  Implement a block level
    interface that allows this information to be bubbled up the stack and
    queried via a new block device ioctl.
    Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
    Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
compat_ioctl.c 22.1 KB