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![Chuck Lever](/assets/img/avatar_default.png)
Helen Chao <helen.chao@oracle.com> noticed that when a user traverses a referral on an NFS/RDMA mount, the resulting submount always uses TCP. This behavior does not match the vers= setting when traversing a referral (vers=4.1 is preserved). It also does not match the behavior of crossing from the pseudofs into a real filesystem (proto=rdma is preserved in that case). The Linux NFS client does not currently support the fs_locations_info attribute. The situation is similar for all NFSv4 servers I know of. Therefore until the community has broad support for fs_locations_info, when following a referral: - First try to connect with RPC-over-RDMA. This will fail quickly if the client has no RDMA-capable interfaces. - If connecting with RPC-over-RDMA fails, or the RPC-over-RDMA transport is not available, use TCP. Reported-by: Helen Chao <helen.chao@oracle.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
517 lines
13 KiB
C
517 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/nfs/nfs4namespace.c
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*
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* Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
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* - Modified by David Howells <dhowells@redhat.com>
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*
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* NFSv4 namespace
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*/
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#include <linux/dcache.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include <linux/nfs_fs.h>
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#include <linux/nfs_mount.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/sunrpc/clnt.h>
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#include <linux/sunrpc/addr.h>
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#include <linux/vfs.h>
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#include <linux/inet.h>
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#include "internal.h"
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#include "nfs4_fs.h"
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#include "dns_resolve.h"
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#define NFSDBG_FACILITY NFSDBG_VFS
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/*
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* Convert the NFSv4 pathname components into a standard posix path.
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*
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* Note that the resulting string will be placed at the end of the buffer
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*/
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static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
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char *buffer, ssize_t buflen)
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{
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char *end = buffer + buflen;
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int n;
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*--end = '\0';
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buflen--;
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n = pathname->ncomponents;
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while (--n >= 0) {
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const struct nfs4_string *component = &pathname->components[n];
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buflen -= component->len + 1;
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if (buflen < 0)
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goto Elong;
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end -= component->len;
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memcpy(end, component->data, component->len);
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*--end = '/';
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}
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return end;
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Elong:
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return ERR_PTR(-ENAMETOOLONG);
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}
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/*
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* return the path component of "<server>:<path>"
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* nfspath - the "<server>:<path>" string
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* end - one past the last char that could contain "<server>:"
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* returns NULL on failure
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*/
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static char *nfs_path_component(const char *nfspath, const char *end)
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{
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char *p;
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if (*nfspath == '[') {
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/* parse [] escaped IPv6 addrs */
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p = strchr(nfspath, ']');
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if (p != NULL && ++p < end && *p == ':')
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return p + 1;
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} else {
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/* otherwise split on first colon */
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p = strchr(nfspath, ':');
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if (p != NULL && p < end)
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return p + 1;
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}
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return NULL;
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}
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/*
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* Determine the mount path as a string
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*/
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static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
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{
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char *limit;
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char *path = nfs_path(&limit, dentry, buffer, buflen,
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NFS_PATH_CANONICAL);
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if (!IS_ERR(path)) {
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char *path_component = nfs_path_component(path, limit);
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if (path_component)
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return path_component;
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}
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return path;
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}
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/*
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* Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
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* believe to be the server path to this dentry
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*/
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static int nfs4_validate_fspath(struct dentry *dentry,
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const struct nfs4_fs_locations *locations,
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char *page, char *page2)
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{
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const char *path, *fs_path;
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path = nfs4_path(dentry, page, PAGE_SIZE);
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if (IS_ERR(path))
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return PTR_ERR(path);
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fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
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if (IS_ERR(fs_path))
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return PTR_ERR(fs_path);
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if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
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dprintk("%s: path %s does not begin with fsroot %s\n",
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__func__, path, fs_path);
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return -ENOENT;
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}
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return 0;
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}
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static size_t nfs_parse_server_name(char *string, size_t len,
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struct sockaddr *sa, size_t salen, struct net *net)
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{
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ssize_t ret;
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ret = rpc_pton(net, string, len, sa, salen);
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if (ret == 0) {
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ret = nfs_dns_resolve_name(net, string, len, sa, salen);
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if (ret < 0)
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ret = 0;
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}
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return ret;
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}
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/**
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* nfs_find_best_sec - Find a security mechanism supported locally
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* @server: NFS server struct
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* @flavors: List of security tuples returned by SECINFO procedure
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*
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* Return an rpc client that uses the first security mechanism in
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* "flavors" that is locally supported. The "flavors" array
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* is searched in the order returned from the server, per RFC 3530
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* recommendation and each flavor is checked for membership in the
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* sec= mount option list if it exists.
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*
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* Return -EPERM if no matching flavor is found in the array.
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*
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* Please call rpc_shutdown_client() when you are done with this rpc client.
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*
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*/
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static struct rpc_clnt *nfs_find_best_sec(struct rpc_clnt *clnt,
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struct nfs_server *server,
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struct nfs4_secinfo_flavors *flavors)
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{
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rpc_authflavor_t pflavor;
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struct nfs4_secinfo4 *secinfo;
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unsigned int i;
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for (i = 0; i < flavors->num_flavors; i++) {
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secinfo = &flavors->flavors[i];
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switch (secinfo->flavor) {
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case RPC_AUTH_NULL:
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case RPC_AUTH_UNIX:
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case RPC_AUTH_GSS:
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pflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
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&secinfo->flavor_info);
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/* does the pseudoflavor match a sec= mount opt? */
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if (pflavor != RPC_AUTH_MAXFLAVOR &&
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nfs_auth_info_match(&server->auth_info, pflavor)) {
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struct rpc_clnt *new;
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struct rpc_cred *cred;
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/* Cloning creates an rpc_auth for the flavor */
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new = rpc_clone_client_set_auth(clnt, pflavor);
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if (IS_ERR(new))
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continue;
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/**
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* Check that the user actually can use the
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* flavor. This is mostly for RPC_AUTH_GSS
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* where cr_init obtains a gss context
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*/
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cred = rpcauth_lookupcred(new->cl_auth, 0);
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if (IS_ERR(cred)) {
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rpc_shutdown_client(new);
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continue;
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}
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put_rpccred(cred);
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return new;
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}
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}
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}
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return ERR_PTR(-EPERM);
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}
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/**
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* nfs4_negotiate_security - in response to an NFS4ERR_WRONGSEC on lookup,
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* return an rpc_clnt that uses the best available security flavor with
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* respect to the secinfo flavor list and the sec= mount options.
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*
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* @clnt: RPC client to clone
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* @inode: directory inode
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* @name: lookup name
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*
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* Please call rpc_shutdown_client() when you are done with this rpc client.
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*/
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struct rpc_clnt *
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nfs4_negotiate_security(struct rpc_clnt *clnt, struct inode *inode,
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const struct qstr *name)
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{
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struct page *page;
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struct nfs4_secinfo_flavors *flavors;
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struct rpc_clnt *new;
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int err;
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page = alloc_page(GFP_KERNEL);
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if (!page)
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return ERR_PTR(-ENOMEM);
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flavors = page_address(page);
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err = nfs4_proc_secinfo(inode, name, flavors);
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if (err < 0) {
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new = ERR_PTR(err);
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goto out;
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}
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new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors);
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out:
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put_page(page);
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return new;
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}
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static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
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char *page, char *page2,
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const struct nfs4_fs_location *location)
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{
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const size_t addr_bufsize = sizeof(struct sockaddr_storage);
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struct net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client);
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struct vfsmount *mnt = ERR_PTR(-ENOENT);
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char *mnt_path;
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unsigned int maxbuflen;
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unsigned int s;
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mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
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if (IS_ERR(mnt_path))
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return ERR_CAST(mnt_path);
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mountdata->mnt_path = mnt_path;
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maxbuflen = mnt_path - 1 - page2;
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mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
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if (mountdata->addr == NULL)
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return ERR_PTR(-ENOMEM);
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for (s = 0; s < location->nservers; s++) {
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const struct nfs4_string *buf = &location->servers[s];
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if (buf->len <= 0 || buf->len >= maxbuflen)
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continue;
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if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
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continue;
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mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
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mountdata->addr, addr_bufsize, net);
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if (mountdata->addrlen == 0)
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continue;
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memcpy(page2, buf->data, buf->len);
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page2[buf->len] = '\0';
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mountdata->hostname = page2;
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snprintf(page, PAGE_SIZE, "%s:%s",
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mountdata->hostname,
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mountdata->mnt_path);
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mnt = vfs_submount(mountdata->dentry, &nfs4_referral_fs_type, page, mountdata);
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if (!IS_ERR(mnt))
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break;
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}
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kfree(mountdata->addr);
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return mnt;
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}
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/**
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* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
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* @dentry - parent directory
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* @locations - array of NFSv4 server location information
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*
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*/
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static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
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const struct nfs4_fs_locations *locations)
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{
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struct vfsmount *mnt = ERR_PTR(-ENOENT);
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struct nfs_clone_mount mountdata = {
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.sb = dentry->d_sb,
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.dentry = dentry,
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.authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
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};
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char *page = NULL, *page2 = NULL;
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int loc, error;
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if (locations == NULL || locations->nlocations <= 0)
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goto out;
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dprintk("%s: referral at %pd2\n", __func__, dentry);
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page = (char *) __get_free_page(GFP_USER);
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if (!page)
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goto out;
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page2 = (char *) __get_free_page(GFP_USER);
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if (!page2)
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goto out;
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/* Ensure fs path is a prefix of current dentry path */
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error = nfs4_validate_fspath(dentry, locations, page, page2);
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if (error < 0) {
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mnt = ERR_PTR(error);
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goto out;
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}
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for (loc = 0; loc < locations->nlocations; loc++) {
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const struct nfs4_fs_location *location = &locations->locations[loc];
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if (location == NULL || location->nservers <= 0 ||
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location->rootpath.ncomponents == 0)
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continue;
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mnt = try_location(&mountdata, page, page2, location);
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if (!IS_ERR(mnt))
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break;
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}
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out:
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free_page((unsigned long) page);
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free_page((unsigned long) page2);
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return mnt;
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}
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/*
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* nfs_do_refmount - handle crossing a referral on server
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* @dentry - dentry of referral
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*
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*/
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static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry)
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{
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struct vfsmount *mnt = ERR_PTR(-ENOMEM);
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struct dentry *parent;
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struct nfs4_fs_locations *fs_locations = NULL;
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struct page *page;
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int err;
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/* BUG_ON(IS_ROOT(dentry)); */
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page = alloc_page(GFP_KERNEL);
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if (page == NULL)
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return mnt;
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fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
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if (fs_locations == NULL)
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goto out_free;
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/* Get locations */
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mnt = ERR_PTR(-ENOENT);
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parent = dget_parent(dentry);
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dprintk("%s: getting locations for %pd2\n",
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__func__, dentry);
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err = nfs4_proc_fs_locations(client, d_inode(parent), &dentry->d_name, fs_locations, page);
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dput(parent);
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if (err != 0 ||
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fs_locations->nlocations <= 0 ||
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fs_locations->fs_path.ncomponents <= 0)
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goto out_free;
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mnt = nfs_follow_referral(dentry, fs_locations);
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out_free:
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__free_page(page);
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kfree(fs_locations);
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return mnt;
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}
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struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
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struct nfs_fh *fh, struct nfs_fattr *fattr)
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{
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rpc_authflavor_t flavor = server->client->cl_auth->au_flavor;
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struct dentry *parent = dget_parent(dentry);
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struct inode *dir = d_inode(parent);
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const struct qstr *name = &dentry->d_name;
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struct rpc_clnt *client;
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struct vfsmount *mnt;
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/* Look it up again to get its attributes and sec flavor */
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client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
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dput(parent);
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if (IS_ERR(client))
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return ERR_CAST(client);
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if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
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mnt = nfs_do_refmount(client, dentry);
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goto out;
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}
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if (client->cl_auth->au_flavor != flavor)
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flavor = client->cl_auth->au_flavor;
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mnt = nfs_do_submount(dentry, fh, fattr, flavor);
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out:
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rpc_shutdown_client(client);
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return mnt;
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}
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/*
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* Try one location from the fs_locations array.
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*
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* Returns zero on success, or a negative errno value.
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*/
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static int nfs4_try_replacing_one_location(struct nfs_server *server,
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char *page, char *page2,
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const struct nfs4_fs_location *location)
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{
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const size_t addr_bufsize = sizeof(struct sockaddr_storage);
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struct net *net = rpc_net_ns(server->client);
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struct sockaddr *sap;
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unsigned int s;
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size_t salen;
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int error;
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sap = kmalloc(addr_bufsize, GFP_KERNEL);
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if (sap == NULL)
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return -ENOMEM;
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error = -ENOENT;
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for (s = 0; s < location->nservers; s++) {
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const struct nfs4_string *buf = &location->servers[s];
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char *hostname;
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if (buf->len <= 0 || buf->len > PAGE_SIZE)
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continue;
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if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
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continue;
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salen = nfs_parse_server_name(buf->data, buf->len,
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sap, addr_bufsize, net);
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if (salen == 0)
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continue;
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rpc_set_port(sap, NFS_PORT);
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error = -ENOMEM;
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hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
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if (hostname == NULL)
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break;
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error = nfs4_update_server(server, hostname, sap, salen, net);
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kfree(hostname);
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if (error == 0)
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break;
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}
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kfree(sap);
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return error;
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}
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/**
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* nfs4_replace_transport - set up transport to destination server
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*
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* @server: export being migrated
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* @locations: fs_locations array
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*
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* Returns zero on success, or a negative errno value.
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*
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* The client tries all the entries in the "locations" array, in the
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* order returned by the server, until one works or the end of the
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* array is reached.
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*/
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int nfs4_replace_transport(struct nfs_server *server,
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const struct nfs4_fs_locations *locations)
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{
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char *page = NULL, *page2 = NULL;
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int loc, error;
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error = -ENOENT;
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if (locations == NULL || locations->nlocations <= 0)
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goto out;
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error = -ENOMEM;
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page = (char *) __get_free_page(GFP_USER);
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if (!page)
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goto out;
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page2 = (char *) __get_free_page(GFP_USER);
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if (!page2)
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goto out;
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|
|
for (loc = 0; loc < locations->nlocations; loc++) {
|
|
const struct nfs4_fs_location *location =
|
|
&locations->locations[loc];
|
|
|
|
if (location == NULL || location->nservers <= 0 ||
|
|
location->rootpath.ncomponents == 0)
|
|
continue;
|
|
|
|
error = nfs4_try_replacing_one_location(server, page,
|
|
page2, location);
|
|
if (error == 0)
|
|
break;
|
|
}
|
|
|
|
out:
|
|
free_page((unsigned long)page);
|
|
free_page((unsigned long)page2);
|
|
return error;
|
|
}
|