Muntz, Daniel wrote: > > >> -----Original Message----- >> From: Steve Dickson [mailto:SteveD@xxxxxxxxxx] >> Sent: Thursday, March 19, 2009 9:18 AM >> To: linux NFS Mailing list >> Subject: The next step: nfsvers=4 >> >> As I see it, the next step to seamlessly move to V4 as the >> default is to make 'mount -o nfsvers=4' actually do a v4 mount... >> >> There are two obvious place we can make this change. >> In the kernel and/or in the mount command... >> >> Looking at the kernel, since v3 and v4 truly two different >> file systems its seems a bit late for the nfs_get_sb() to all >> of sudden have to change file system type. Meaning when >> nfs_get_sb() sees the "nfsvers=4" somehow it would have to >> back out and call nfs4_get_sb(), which obviously is a bit hacky.... >> >> Now I guess we could have one nfs_get_sb() for both v3 and v4. >> Where the nfs_get_sb() could peek into the options data to >> see which version is needed. This would also mean the mount >> command would always have to set a version so when the "nfsvers=" >> options is not set, the kernel would know which version to use. >> Again, this feels a bit hacky as well but doable... >> >> At least to me, what seems like the best option is to have >> the mount.nfs binary early on intercept "nfsvers=4" option >> and then change the fs_type to "nfs4", which would allow >> everything to "trickle down" as it does today... Again to me, >> that seem like the least intrusive way to do it... >> >> Comments? Is there other ways? > > Whichever way it's done, if v4 becomes the default, don't forget to also > make the default behavior be that the system will fall back and try a v3 > mount if v4 isn't available. Otherwise you'll break a huge percentage > of your user base. Of course then you also have to deal with the > semantics of how to specifify "only v4" vs. "try v4 first and fall > back". No worries... falling back to v3/v2 will be the will definitely happen before the switch is made... This was this is reason I'm pushing for a mount configuration file. So the semantics of which version is or is not tried can be defined locally... steved. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
