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    virtio_blk: Add 'serial' attribute to virtio-blk devices (v2) · a5eb9e4f
    Ryan Harper 提交于
    Create a new attribute for virtio-blk devices that will fetch the serial number
    of the block device.  This attribute can be used by udev to create disk/by-id
    symlinks for devices that don't have a UUID (filesystem) associated with them.
    
    ATA_IDENTIFY strings are special in that they can be up to 20 chars long
    and aren't required to be nul-terminated.  The buffer is also zero-padded
    meaning that if the serial is 19 chars or less that we get a nul-terminated
    string.  When copying this value into a string buffer, we must be careful to
    copy up to the nul (if it present) and only 20 if it is longer and not to
    attempt to nul terminate; this isn't needed.
    
    Changes since v1:
    - Added BUILD_BUG_ON() for PAGE_SIZE check
    - Removed min() since BUILD_BUG_ON() handles the check
    - Replaced serial_sysfs() by copying id directly to buffer
    Signed-off-by: NRyan Harper <ryanh@us.ibm.com>
    Signed-off-by: Njohn cooper <john.cooper@redhat.com>
    Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
    a5eb9e4f
virtio_blk.c 14.5 KB