• Josef Bacik's avatar
    Btrfs: change how we wait for pending ordered extents · 161c3549
    Josef Bacik authored
    
    
    We have a mechanism to make sure we don't lose updates for ordered extents that
    were logged in the transaction that is currently running.  We add the ordered
    extent to a transaction list and then the transaction waits on all the ordered
    extents in that list.  However are substantially large file systems this list
    can be extremely large, and can give us soft lockups, since the ordered extents
    don't remove themselves from the list when they do complete.
    
    To fix this we simply add a counter to the transaction that is incremented any
    time we have a logged extent that needs to be completed in the current
    transaction.  Then when the ordered extent finally completes it decrements the
    per transaction counter and wakes up the transaction if we are the last ones.
    This will eliminate the softlockup.  Thanks,
    Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
    Signed-off-by: default avatarChris Mason <clm@fb.com>
    161c3549