• Boaz Harrosh's avatar
    ore: RAID5 read · a1fec1db
    Boaz Harrosh authored
    
    
    This patch introduces the first stage of RAID5 support
    mainly the skip-over-raid-units when reading. For
    writes it inserts BLANK units, into where XOR blocks
    should be calculated and written to.
    
    It introduces the new "general raid maths", and the main
    additional parameters and components needed for raid5.
    
    Since at this stage it could corrupt future version that
    actually do support raid5. The enablement of raid5
    mounting and setting of parity-count > 0 is disabled. So
    the raid5 code will never be used. Mounting of raid5 is
    only enabled later once the basic XOR write is also in.
    But if the patch "enable RAID5" is applied this code has
    been tested to be able to properly read raid5 volumes
    and is according to standard.
    
    Also it has been tested that the new maths still properly
    supports RAID0 and grouping code just as before.
    (BTW: I have found more bugs in the pnfs-obj RAID math
     fixed here)
    
    The ore.c file is getting too big, so new ore_raid.[hc]
    files are added that will include the special raid stuff
    that are not used in striping and mirrors. In future write
    support these will get bigger.
    When adding the ore_raid.c to Kbuild file I was forced to
    rename ore.ko to libore.ko. Is it possible to keep source
    file, say ore.c and module file ore.ko the same even if there
    are multiple files inside ore.ko?
    
    Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
    a1fec1db