[PATCH 3/5] [XFS] Block callers of xfs_flush_inodes() correctly.

[Christoph Hellwig]

On Sun, Mar 15, 2009 at 10:31:45PM +1100, Dave Chinner wrote:
> xfs_flush_inodes() currently uses a magic timeout to wait for
> some inodes to be flushed before returning. This isn't
> really reliable but used to be the best that could be done
> due to deadlock potential of waiting for the entire flush.
> 
> Now the inode flush is safe to execute while we hold page
> and inode locks, we can wait for all the inodes to flush
> synchronously. Convert the wait mechanism to a completion
> to do this efficiently. This should remove all remaining
> spurious ENOSPC errors from the delayed allocation reservation
> path.

Why do we queue it up to a different thread if we synchronously wait
for it anyway?