roland wrote: > in linux, there is an option for this. :) > And that doesn't mean that it is right for OpenSolaris. There are underlying assumptions in both operating systems. What works in one may not work in another.
> could you be more specific what code it would break or what would be so ugly > with this? > > iirc, when taking a look at the linux nfsd code, it was just a matter of > checking each subdir if it`s a mountpoint or not and then either creating > another share or just skip over. > 1) How do you detect the case that the server admin does not want to share a sub-filesystem? What if we have: /export/home rw /export/projects/engr ro /export/projects/acct rw where both /export/projects/engr and /export/projects/acct are on the same filesystem. And someone does cd /export/home/thud ln -s /export/projects/engr/nfsv41/kspe . And so is /export/projects/engr/nfsv41. Both /export/projects/engr and /export/projects/acct have the same FSID as /export/projects/engr/nfsv41. We do: client> mount server:/export/home /mnt client> cd /mnt client> cd thud client> cd kspe And there is no share on /export/projects/engr/kspe. Should we hand out a rw share at that point? 2) Lets say that the user did: client> mount server:/export/projects/engr /mnt2 client> cd /mnt2/kspe client> cd prototype The server reboots now. Which share applies when the client presents their cached FH? The answer depends on whether or not this is NFSv3 or NFSv4. The answer depends on whether or not the server embeds the share information in the FH. Lets say it does embed the share information in the FH - that is an ephemeral share, it is not persistent across reboots. Given the presence of hard and soft links, how does the server determine which share point is the parent? 3) Can you get at cycles with either hard or soft links? Both types of links are a pain to code for and you have to remember them when you design. Converting from inode to parent (i.e., to determine pathname from a inode) can be a hard problem. And in many ways, the scenarios I am describing above are this problem. 4) Output from showmount -e will differ over time. ======== It is much simpler if we follow the rule that the server admin explicitly shares the resources of the server. Either use inheritance to mimic what you want here or manually set each share. > so, would it really be so difficult or ugly to make this possible with > solaris nfsd, too? > You can talk about whether it is an easy technical hack - sure. But you also have to talk about what would the impact be on our quality, ease of maintaining this code, interoperability with other parts of OpenSolaris, our security model, and what do our users expect.
