• NeilBrown's avatar
    md: restore ability of spare drives to spin down. · 1176568d
    NeilBrown authored
    Some time ago we stopped the clean/active metadata updates
    from being written to a 'spare' device in most cases so that
    it could spin down and say spun down.  Device failure/removal
    etc are still recorded on spares.
    
    However commit 51d5668c broke this 50% of the time,
    depending on whether the event count is even or odd.
    The change log entry said:
    
       This means that the alignment between 'odd/even' and
        'clean/dirty' might take a little longer to attain,
    
    how ever the code makes no attempt to create that alignment, so it
    could take arbitrarily long.
    
    So when we find that clean/dirty is not aligned with odd/even,
    force a second metadata-update immediately.  There are already cases
    where a second metadata-update is needed immediately (e.g. when a
    device fails during the metadata update).  We just piggy-back on that.
    Reported-by: default avatarJoe Bryant <tenminjoe@yahoo.com>
    Signed-off-by: default avatarNeilBrown <neilb@suse.de>
    Cc: stable@kernel.org
    1176568d
md.c 185 KB