On Thu, 2009-08-20 at 12:54 -0400, Chuck Lever wrote: > > I'm not too concerned. As it says above, this is a sample that > > illustrates how you could do it. It does work, though, so people can > > definitely use it to test the functionality. > > I'm thinking of when we want to add new upcalls, since you went to > some length to generalize this facility. It would be easier to manage > adding a new script than it would to update an existing one, and an > admin or distributor could control what scripts are present, or > provide their own. > > The act of editing a single script is easy enough, but then you have > to worry about updates from the distributor possibly overwriting the > local modifications, and so on, and so on. > > A model like /etc/init.d might be easier to manage in the long run. True, and we might want to consider adding something like that into nfs-utils. Yes, I did generalise the facility: I'm planning on redoing the NFSv4 idmapper at some point soon. > >>> +#define NFS_DNS_HASHBITS 4 > >>> +#define NFS_DNS_HASHTBL_SIZE (1 << NFS_DNS_HASHBITS) > >> > >> So the hash table is only 16 buckets. Is it really worth the trouble > >> of keeping a small cache of hostname lookups in the kernel? I > >> guess I > >> don't have a clear idea of how often you need to handle DNS > >> resolution > >> for FS_LOCATIONS. > > > > At the moment, the number of referrals out there are few, but we're > > expecting that to grow when the whole federated fs management > > infrastructure develops. > > OK. Can you give some sense of quantity? Could be in the hundreds in a large organisation. Then again, if we go do the equivalent of /afs, it could be in the thousands. We'll see how that turns out. > >>> +#define NFS_DNS_HOSTNAME_MAXLEN (128) > >> > >> It looks like you are using this to size the target buffer for a > >> presentation address, not a hostname. Perhaps you should use > >> INET6_ADDRSTRLEN+IPV6_SCOPEID_LEN+1 here instead, and/or change the > >> name of the macro. > > > > No. I'm using it primarily to store the hostname. See nfs_dns_parse(). > > OK, you store the presentation address in buf1 first, and now I see > that farther down you are storing the hostname too. But note that the > maximum size of a hostname is 1024 (see the definition of NI_MAXHOST > in user space). > > If there is a protocol specified limit on the hostname string returned > via FS_LOCATION, perhaps that should be noted here. Otherwise, 128 is > too small, I think. There is no limit in the protocol, but DNS names that are larger than 64 bytes will not fit into a Linux utsname structure. For that reason, I think 128 characters is sufficient. Anybody who has to type www.<122 characters>.com has my sympathy, and deepest regrets... -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@xxxxxxxxxx www.netapp.com -- 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
