Date: Sun, 12 Jun 2005 04:26:12 -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: <20050612082612.GF66188@green.homeunix.org> In-Reply-To: <20050612080833.GJ17867@elvis.mu.org> References: <200506102350.j5ANofFM008212@repoman.freebsd.org> <20050611034930.GY17867@elvis.mu.org> <20050611064956.GC66188@green.homeunix.org> <20050611141021.GD17867@elvis.mu.org> <20050611170425.GD66188@green.homeunix.org> <20050611174617.GE17867@elvis.mu.org> <20050611212534.GE66188@green.homeunix.org> <20050612080833.GJ17867@elvis.mu.org>
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On Sun, Jun 12, 2005 at 01:08:33AM -0700, Alfred Perlstein wrote: > * Brian Fundakowski Feldman <green@freebsd.org> [050611 14:25] wrote: > > On Sat, Jun 11, 2005 at 10:46:17AM -0700, Alfred Perlstein wrote: > > > * Brian Fundakowski Feldman <green@freebsd.org> [050611 10:04] wrote: > > > > > > > > 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. > > > > > > lol. > > > FWIW, I was aware of Terry's explanation, I just consider it bunk. > > > > Heh. Well, we can always throw things under a kernel option. I never > > saw Terry's e-mail on the topic until just now -- my understanding was > > that this was generally the Right Thing To Do after spending a while > > reading POSIX/SUS (due to gad pointing out that it was definitely a > > bad idea to just return short writes). > > Seriously, have you tested what happens to a libc_r app that > opens an nfs file F_SYNC? My guess is that it's not pretty. This code path is related to O_NONBLOCK, not O_FSYNC. O_FSYNC is synonymous with the slow fallback path that large transactional block now takes, rather than deadlocking. O_NONBLOCK really means that whatever they do, they are required to check for EAGAIN. -- Brian Fundakowski Feldman \'[ FreeBSD ]''''''''''\ <> green@FreeBSD.org \ The Power to Serve! \ Opinions expressed are my own. \,,,,,,,,,,,,,,,,,,,,,,\
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