Date: Sat, 11 Jun 2005 13:04:25 -0400 From: Brian Fundakowski Feldman <green@freebsd.org> To: Alfred Perlstein <alfred@freebsd.org> Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: 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 Message-ID: <20050611170425.GD66188@green.homeunix.org> In-Reply-To: <20050611141021.GD17867@elvis.mu.org> References: <200506102350.j5ANofFM008212@repoman.freebsd.org> <20050611034930.GY17867@elvis.mu.org> <20050611064956.GC66188@green.homeunix.org> <20050611141021.GD17867@elvis.mu.org>
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On Sat, Jun 11, 2005 at 07:10:21AM -0700, Alfred Perlstein wrote: > * Brian Fundakowski Feldman <green@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"? :) Well, the easy solution is just fsync(2) :) This change jibes with Terry's explanation (thanks, Juli). It would be good to implement the rest of the functionality for non-blocking NFS client, too, but I think that can be dne gradually over time. -- Brian Fundakowski Feldman \'[ FreeBSD ]''''''''''\ <> green@FreeBSD.org \ The Power to Serve! \ Opinions expressed are my own. \,,,,,,,,,,,,,,,,,,,,,,\
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