"Serge E. Hallyn" <[email protected]> writes:
> Quoting Sam Vilain ([email protected]):
>> Kirill Korotaev wrote:
>>
>> >Serge,
>> >
>> >BTW, have you noticed that NFS is using utsname for internal processes
>> >and in general case this makes NFS ns to be coupled with uts ns?
>> >
>> >
>>
>> Either that, or each NFS vfsmount has a uts_ns pointer.
>
> Sorry, I must be being dense. I only see utsname being used in the case
> of nfsroot. Can you point me to where you're talking about?
We have the nfs lockd client code, and the sunrpc code.
I've been fighting a few a cold and some 2.6.17-rc1 bugs
so I haven't had a chance to drill down yet to see what
the system_utsname.nodename is actually being used for.
Until we actually understand what is happening it is too soon to
judge if it is a problem or not.
The nfsroot is clearly not a problem.
As for the other cases I'm not certain.
So skimming through the code quickly.
include/linux/lockd/lockd.h
> #define NLMCLNT_OHSIZE (sizeof(system_utsname.nodename)+10)
fs/lockd/xdr.c
> #define NLM_caller_sz 1+XDR_QUADLEN(sizeof(system_utsname.nodename))
The previous two are just sizes, so not interesting for analysis.
fs/lockd/clntproc.c
> static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
> {
> struct nlm_args *argp = &req->a_args;
> struct nlm_lock *lock = &argp->lock;
>
> nlmclnt_next_cookie(&argp->cookie);
> argp->state = nsm_local_state;
> memcpy(&lock->fh, NFS_FH(fl->fl_file->f_dentry->d_inode), sizeof(struct nfs_fh));
> lock->caller = system_utsname.nodename;
> lock->oh.data = req->a_owner;
> lock->oh.len = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
> (unsigned int)fl->fl_u.nfs_fl.owner->pid,
> system_utsname.nodename);
> lock->svid = fl->fl_u.nfs_fl.owner->pid;
> lock->fl.fl_start = fl->fl_start;
> lock->fl.fl_end = fl->fl_end;
> lock->fl.fl_type = fl->fl_type;
> }
I think this just creates a unique string with nodename+pid
fs/lockd/mon.c
> xdr_encode_common(struct rpc_rqst *rqstp, u32 *p, struct nsm_args *argp)
> {
> char buffer[20];
>
> /*
> * Use the dotted-quad IP address of the remote host as
> * identifier. Linux statd always looks up the canonical
> * hostname first for whatever remote hostname it receives,
> * so this works alright.
> */
> sprintf(buffer, "%u.%u.%u.%u", NIPQUAD(argp->addr));
> if (!(p = xdr_encode_string(p, buffer))
> || !(p = xdr_encode_string(p, system_utsname.nodename)))
> return ERR_PTR(-EIO);
> *p++ = htonl(argp->prog);
> *p++ = htonl(argp->vers);
> *p++ = htonl(argp->proc);
>
> return p;
> }
This looks like it is just general server information
fs/lockd/svclock.c
> /*
> * Initialize arguments for GRANTED call. The nlm_rqst structure
> * has been cleared already.
> */
> static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
> {
> locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
> memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
> call->a_args.lock.caller = system_utsname.nodename;
> call->a_args.lock.oh.len = lock->oh.len;
>
> /* set default data area */
> call->a_args.lock.oh.data = call->a_owner;
> call->a_args.lock.svid = lock->fl.fl_pid;
>
> if (lock->oh.len > NLMCLNT_OHSIZE) {
> void *data = kmalloc(lock->oh.len, GFP_KERNEL);
> if (!data)
> return 0;
> call->a_args.lock.oh.data = (u8 *) data;
> }
>
> memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
> return 1;
> }
I think this is just a uniq identifier again.
net/sunrpc/clnt.c
> /*
> * Create an RPC client
> * FIXME: This should also take a flags argument (as in task->tk_flags).
> * It's called (among others) from pmap_create_client, which may in
> * turn be called by an async task. In this case, rpciod should not be
> * made to sleep too long.
> */
> struct rpc_clnt *
> rpc_new_client(struct rpc_xprt *xprt, char *servname,
> struct rpc_program *program, u32 vers,
> rpc_authflavor_t flavor)
> {
> struct rpc_version *version;
> struct rpc_clnt *clnt = NULL;
> struct rpc_auth *auth;
> int err;
> int len;
>
> dprintk("RPC: creating %s client for %s (xprt %p)\n",
> program->name, servname, xprt);
>
> err = -EINVAL;
> if (!xprt)
> goto out_no_xprt;
> if (vers >= program->nrvers || !(version = program->version[vers]))
> goto out_err;
>
> err = -ENOMEM;
> clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
> if (!clnt)
> goto out_err;
> memset(clnt, 0, sizeof(*clnt));
> atomic_set(&clnt->cl_users, 0);
> atomic_set(&clnt->cl_count, 1);
> clnt->cl_parent = clnt;
>
> clnt->cl_server = clnt->cl_inline_name;
> len = strlen(servname) + 1;
> if (len > sizeof(clnt->cl_inline_name)) {
> char *buf = kmalloc(len, GFP_KERNEL);
> if (buf != 0)
> clnt->cl_server = buf;
> else
> len = sizeof(clnt->cl_inline_name);
> }
> strlcpy(clnt->cl_server, servname, len);
>
> clnt->cl_xprt = xprt;
> clnt->cl_procinfo = version->procs;
> clnt->cl_maxproc = version->nrprocs;
> clnt->cl_protname = program->name;
> clnt->cl_pmap = &clnt->cl_pmap_default;
> clnt->cl_port = xprt->addr.sin_port;
> clnt->cl_prog = program->number;
> clnt->cl_vers = version->number;
> clnt->cl_prot = xprt->prot;
> clnt->cl_stats = program->stats;
> clnt->cl_metrics = rpc_alloc_iostats(clnt);
> rpc_init_wait_queue(&clnt->cl_pmap_default.pm_bindwait, "bindwait");
>
> if (!clnt->cl_port)
> clnt->cl_autobind = 1;
>
> clnt->cl_rtt = &clnt->cl_rtt_default;
> rpc_init_rtt(&clnt->cl_rtt_default, xprt->timeout.to_initval);
>
> err = rpc_setup_pipedir(clnt, program->pipe_dir_name);
> if (err < 0)
> goto out_no_path;
>
> auth = rpcauth_create(flavor, clnt);
> if (IS_ERR(auth)) {
> printk(KERN_INFO "RPC: Couldn't create auth handle (flavor %u)\n",
> flavor);
> err = PTR_ERR(auth);
> goto out_no_auth;
> }
>
> /* save the nodename */
> clnt->cl_nodelen = strlen(system_utsname.nodename);
> if (clnt->cl_nodelen > UNX_MAXNODENAME)
> clnt->cl_nodelen = UNX_MAXNODENAME;
> memcpy(clnt->cl_nodename, system_utsname.nodename, clnt->cl_nodelen);
> return clnt;
>
> out_no_auth:
> if (!IS_ERR(clnt->cl_dentry)) {
> rpc_rmdir(clnt->cl_pathname);
> dput(clnt->cl_dentry);
> rpc_put_mount();
> }
> out_no_path:
> if (clnt->cl_server != clnt->cl_inline_name)
> kfree(clnt->cl_server);
> kfree(clnt);
> out_err:
> xprt_destroy(xprt);
> out_no_xprt:
> return ERR_PTR(err);
> }
This appears to be restricted to cache nodename when an rpc
connection is setup.
So I think we are ok but we need to be certain.
Eric
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