Messages in this thread Patch in this message | | | Date | Tue, 29 Jun 1999 01:38:35 +0100 (GMT) | From | Riley Williams <> | Subject | Re: knfsd and submounts |
| |
Hi Matthew.
>>>> Emulate Sun NFS daemon >>>> CONFIG_NFSD_SUN >>>> If you would like for the server to allow clients to access >>>> directories that are mount points on the local filesystem >>>> (this is how nfsd behaves on Sun systems), say yes here. If >>>> unsure, say N.
>> Plainly, the CONFIG_NFSD_SUN does something other than what the >> Configure.help says it does. I'm not sure what, but it *doesn't* >> allow submounts to be viewed as part of the total exported >> filesystem; only the physical partition is exported, and not any >> of the other partitions mounted on the exported partition (I >> know, we export directories, by for clarity's sake...)
> That isn't what the Configure.help entry claims to do though. > Let me illustrate:
> On the server we have two filesystems, / and /usr. On the / > filesystem, we have a /usr directory which has a file `foo' in > it. But the /usr filesystem is mounted on top of the directory > which contains foo, so on the server one sees the contents of > the /usr filesystem, which does not include the file `foo'. The > question is, when one exports /, does one get to see /usr/foo or > not? And that is what CONFIG_NFSD_SUN decides. The only place > this is mentioned is in fs/nfsd/vfs.c:
> #ifndef CONFIG_NFSD_SUN > if (dentry->d_mounts != dentry) { > return nfserr_perm; > } > #endif
> That is, the behavior with CONFIG_NFSD_SUN set to No is to check > if this is a mountpoint and if it is, return a permission error. > If CONFIG_NFSD_SUN is turned on, one can see `under' a mount > point on the server.
I have to admit thaat I was under the saame misunderstanding regaarding thaat option...
> Would someone care to knock up a better description for this > config option and submit it as a patch to Linus? The current > text is evidently confusing.
Perhaps I can suggest the enclosed patch - if you like it, you can forward it to Linus...
Best wishes from Riley.
+----------------------------------------------------------------------+ | There is something frustrating about the quality and speed of Linux | | development, ie., the quality is too high and the speed is too high, | | in other words, I can implement this XXXX feature, but I bet someone | | else has already done so and is just about to release their patch. | +----------------------------------------------------------------------+ * ftp://ftp.MemAlpha.cx/pub/rhw/Linux * http://www.MemAlpha.cx/kernel.versions.html --- Configure.help~ Mon Jun 14 03:54:06 1999 +++ Configure.help Tue Jun 29 01:32:42 1999 @@ -7163,9 +7163,21 @@ Emulate Sun NFS daemon CONFIG_NFSD_SUN - If you would like for the server to allow clients to access - directories that are mount points on the local filesystem (this is - how nfsd behaves on Sun systems), say yes here. If unsure, say N. + If you say Y here, then when this system is used as an NFS server, + the behaviour of nfsd on Sun systems will be emulated. If you say + N here, then a cleaner (and potentially more secure) behavioural + style will be used. If unsure, say N. + + To clarify the behaviour of Sun systems in this respect, imagine a + system where the /home/ftp partition has a subdirectory pub with a + file in it called pub/.message and where a second partition has + been munted over /home/ftp/pub and has thus hidden the pub/.message + file. + + With the Sun systems behaviour, that hidden pub/.message file will + be visible to NFS clients that mount the /home/ftp partition from + your server, UNLESS they also mount the /home/ftp/pub partition on + top of it. OS/2 HPFS filesystem support (read only) CONFIG_HPFS_FS | |