On Fri, Feb 21, 2025 at 12:54 PM Gleb Smirnoff <gleb...@freebsd.org> wrote: > > On Fri, Feb 21, 2025 at 05:06:16AM -0800, Rick Macklem wrote: > R> Agreed. Unfortunatey, the return values for getaddrinfo(3) do not clearly > R> differentiate between them. I think Gleb's case returns EAI_FAIL, which is > also > R> returned for other failures. I think EAI_NONAME is returned for the case > where > R> the resolver (dns, /etc/hosts or ???) does determine that the name is > bogus. > R> > R> I suppose the code could do retries for all return values other than > EAI_NONAME, > R> but to me that would still be a POLA violation, since the current > R> behaviour has been > R> in place for decades (as others have noted). Also, some of the > R> feedback here has > R> been "It is not broken, don't fix it", if I interpreted it correctly. > R> A new option avoids > R> changing the default behaviour. > > I would argue that there is no POLA breakage here. POLA violation means that > people would need to learn something new, different to what they were doing > for > years. E.g, they need to run a new command to achieve same result as they did > before, or run they same command but observe a different result. The fix does > changes behavior of mount_nfs, but does it change anything for a user, an > operator or a sysadmin? What about the case where without any patch, the mount fails and the system continues to boot normally otherwise, whereas with a patch, the system hangs while booting, trying to do the mount? (Although you noted different behaviour for "late", I believe an NFS mount without "bg" should block further startup until the mount succeeds. An NFS mounted /usr, for example.)
I have put a patch up on phabricator as D49104 which I hope you can test/review, ignoring the fact that you do not think fixing it by default is a POLA violation. rick > > * Those who use IP addresses in /etc/fstab - nothing changes for them. > * Those who use name from /etc/hosts in /etc/fstab - nothing changess for > them. > * Those who use DNS names in /etc/fstab (but didn't run into issues until now) > - nothing changes for them. And a potential issue is fixed for them. > > What about somebody, who run mount_nfs(8) from command line? First, they > would > need to run with 'bg' option, to see any behavior difference, which is already > very uncommon for command line mount_nfs. Second, again nothing changes for > them if everything is all right with their network. Only if their network/DNS > is off, they would see mount_nfs(8) going into background instead of failing. > I > do claim that this is a positive change, someone would argue that people may > use mount_nfs(8) as a probe for working DNS and that would be broken. Well, > very far fetched POLA violation. > > -- > Gleb Smirnoff
