cvs commit: src/sys/nfsclient nfs_bio.c nfs_vfsops.c nfsargs.h nfsmount.h src/sys/sys buf.h bufobj.h src/sys/kern vfs_bio.c

[Alfred Perlstein]

* Brian Fundakowski Feldman <green at freebsd.org> [050610 23:49] wrote:
> On Fri, Jun 10, 2005 at 08:49:30PM -0700, Alfred Perlstein wrote:
> > Returning EAGAIN from a disk IO seems bogus, are you sure it makes
> > sense to do that when IO_NDELAY is set?  Shouldn't it just be ignored
> > like other FSes do?
> 
> Well, it's not disk IO, it's network IO.  I figure if you set that
> flag you should expect commensurate error return values.  This is
> conceivably a useful behavior, and POSIX does not forbid it, so I just
> made the judgement call to not deny the functionality.
> 
> Would you actually be surprised to get EAGAIN if you requested
> non-blocking access to a file stream, ignoring the fact that it just
> happens to not have been done already for other S_ISREG file streams?

How does one poll(2) or kqueue(2) to determine when EAGAIN will
"go away" ?  Maybe I'm misreading the code, but it appears that
O_FSYNC writes on a non-blocking write will _always_ return
EAGAIN?  So when is it safe to "AGAIN"? :)

-- 
- Alfred Perlstein
- email: bright at mu.org cell: 408-480-4684