• NeilBrown's avatar
    [PATCH] md: fix up some rdev rcu locking in raid5/6 · 9910f16a
    NeilBrown authored
    There is this "FIXME" comment with a typo in it!!  that been annoying me for
    days, so I just had to remove it.
    
    conf->disks[i].rdev should only be accessed if
      - we know we hold a reference or
      - the mddev->reconfig_sem is down or
      - we have a rcu_readlock
    
    handle_stripe was referencing rdev in three places without any of these.  For
    the first two, get an rcu_readlock.  For the last, the same access
    (md_sync_acct call) is made a little later after the rdev has been claimed
    under and rcu_readlock, if R5_Syncio is set.  So just use that access...
    However R5_Syncio isn't really needed as the 'syncing' variable contains the
    same information.  So use that instead.
    
    Issues, comment, and fix are identical in raid5 and raid6.
    Signed-off-by: default avatarNeil Brown <neilb@suse.de>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    9910f16a
raid5.h 10.4 KB