1 /* 2 * linux/fs/nfs/nfs4namespace.c 3 * 4 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com> 5 * - Modified by David Howells <dhowells@redhat.com> 6 * 7 * NFSv4 namespace 8 */ 9 10 #include <linux/dcache.h> 11 #include <linux/mount.h> 12 #include <linux/namei.h> 13 #include <linux/nfs_fs.h> 14 #include <linux/string.h> 15 #include <linux/sunrpc/clnt.h> 16 #include <linux/vfs.h> 17 #include <linux/inet.h> 18 #include "internal.h" 19 #include "nfs4_fs.h" 20 21 #define NFSDBG_FACILITY NFSDBG_VFS 22 23 /* 24 * Convert the NFSv4 pathname components into a standard posix path. 25 * 26 * Note that the resulting string will be placed at the end of the buffer 27 */ 28 static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname, 29 char *buffer, ssize_t buflen) 30 { 31 char *end = buffer + buflen; 32 int n; 33 34 *--end = '\0'; 35 buflen--; 36 37 n = pathname->ncomponents; 38 while (--n >= 0) { 39 const struct nfs4_string *component = &pathname->components[n]; 40 buflen -= component->len + 1; 41 if (buflen < 0) 42 goto Elong; 43 end -= component->len; 44 memcpy(end, component->data, component->len); 45 *--end = '/'; 46 } 47 return end; 48 Elong: 49 return ERR_PTR(-ENAMETOOLONG); 50 } 51 52 /* 53 * Determine the mount path as a string 54 */ 55 static char *nfs4_path(const struct vfsmount *mnt_parent, 56 const struct dentry *dentry, 57 char *buffer, ssize_t buflen) 58 { 59 const char *srvpath; 60 61 srvpath = strchr(mnt_parent->mnt_devname, ':'); 62 if (srvpath) 63 srvpath++; 64 else 65 srvpath = mnt_parent->mnt_devname; 66 67 return nfs_path(srvpath, mnt_parent->mnt_root, dentry, buffer, buflen); 68 } 69 70 /* 71 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we 72 * believe to be the server path to this dentry 73 */ 74 static int nfs4_validate_fspath(const struct vfsmount *mnt_parent, 75 const struct dentry *dentry, 76 const struct nfs4_fs_locations *locations, 77 char *page, char *page2) 78 { 79 const char *path, *fs_path; 80 81 path = nfs4_path(mnt_parent, dentry, page, PAGE_SIZE); 82 if (IS_ERR(path)) 83 return PTR_ERR(path); 84 85 fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE); 86 if (IS_ERR(fs_path)) 87 return PTR_ERR(fs_path); 88 89 if (strncmp(path, fs_path, strlen(fs_path)) != 0) { 90 dprintk("%s: path %s does not begin with fsroot %s\n", 91 __func__, path, fs_path); 92 return -ENOENT; 93 } 94 95 return 0; 96 } 97 98 static struct vfsmount *try_location(struct nfs_clone_mount *mountdata, 99 char *page, char *page2, 100 const struct nfs4_fs_location *location) 101 { 102 struct vfsmount *mnt = ERR_PTR(-ENOENT); 103 char *mnt_path; 104 unsigned int maxbuflen; 105 unsigned int s; 106 107 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE); 108 if (IS_ERR(mnt_path)) 109 return mnt; 110 mountdata->mnt_path = mnt_path; 111 maxbuflen = mnt_path - 1 - page2; 112 113 for (s = 0; s < location->nservers; s++) { 114 const struct nfs4_string *buf = &location->servers[s]; 115 struct sockaddr_storage addr; 116 117 if (buf->len <= 0 || buf->len >= maxbuflen) 118 continue; 119 120 mountdata->addr = (struct sockaddr *)&addr; 121 122 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len)) 123 continue; 124 nfs_parse_ip_address(buf->data, buf->len, 125 mountdata->addr, &mountdata->addrlen); 126 if (mountdata->addr->sa_family == AF_UNSPEC) 127 continue; 128 nfs_set_port(mountdata->addr, NFS_PORT); 129 130 memcpy(page2, buf->data, buf->len); 131 page2[buf->len] = '\0'; 132 mountdata->hostname = page2; 133 134 snprintf(page, PAGE_SIZE, "%s:%s", 135 mountdata->hostname, 136 mountdata->mnt_path); 137 138 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata); 139 if (!IS_ERR(mnt)) 140 break; 141 } 142 return mnt; 143 } 144 145 /** 146 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error 147 * @mnt_parent - mountpoint of parent directory 148 * @dentry - parent directory 149 * @locations - array of NFSv4 server location information 150 * 151 */ 152 static struct vfsmount *nfs_follow_referral(const struct vfsmount *mnt_parent, 153 const struct dentry *dentry, 154 const struct nfs4_fs_locations *locations) 155 { 156 struct vfsmount *mnt = ERR_PTR(-ENOENT); 157 struct nfs_clone_mount mountdata = { 158 .sb = mnt_parent->mnt_sb, 159 .dentry = dentry, 160 .authflavor = NFS_SB(mnt_parent->mnt_sb)->client->cl_auth->au_flavor, 161 }; 162 char *page = NULL, *page2 = NULL; 163 int loc, error; 164 165 if (locations == NULL || locations->nlocations <= 0) 166 goto out; 167 168 dprintk("%s: referral at %s/%s\n", __func__, 169 dentry->d_parent->d_name.name, dentry->d_name.name); 170 171 page = (char *) __get_free_page(GFP_USER); 172 if (!page) 173 goto out; 174 175 page2 = (char *) __get_free_page(GFP_USER); 176 if (!page2) 177 goto out; 178 179 /* Ensure fs path is a prefix of current dentry path */ 180 error = nfs4_validate_fspath(mnt_parent, dentry, locations, page, page2); 181 if (error < 0) { 182 mnt = ERR_PTR(error); 183 goto out; 184 } 185 186 for (loc = 0; loc < locations->nlocations; loc++) { 187 const struct nfs4_fs_location *location = &locations->locations[loc]; 188 189 if (location == NULL || location->nservers <= 0 || 190 location->rootpath.ncomponents == 0) 191 continue; 192 193 mnt = try_location(&mountdata, page, page2, location); 194 if (!IS_ERR(mnt)) 195 break; 196 } 197 198 out: 199 free_page((unsigned long) page); 200 free_page((unsigned long) page2); 201 dprintk("%s: done\n", __func__); 202 return mnt; 203 } 204 205 /* 206 * nfs_do_refmount - handle crossing a referral on server 207 * @dentry - dentry of referral 208 * @nd - nameidata info 209 * 210 */ 211 struct vfsmount *nfs_do_refmount(const struct vfsmount *mnt_parent, struct dentry *dentry) 212 { 213 struct vfsmount *mnt = ERR_PTR(-ENOMEM); 214 struct dentry *parent; 215 struct nfs4_fs_locations *fs_locations = NULL; 216 struct page *page; 217 int err; 218 219 /* BUG_ON(IS_ROOT(dentry)); */ 220 dprintk("%s: enter\n", __func__); 221 222 page = alloc_page(GFP_KERNEL); 223 if (page == NULL) 224 goto out; 225 226 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL); 227 if (fs_locations == NULL) 228 goto out_free; 229 230 /* Get locations */ 231 mnt = ERR_PTR(-ENOENT); 232 233 parent = dget_parent(dentry); 234 dprintk("%s: getting locations for %s/%s\n", 235 __func__, parent->d_name.name, dentry->d_name.name); 236 237 err = nfs4_proc_fs_locations(parent->d_inode, &dentry->d_name, fs_locations, page); 238 dput(parent); 239 if (err != 0 || 240 fs_locations->nlocations <= 0 || 241 fs_locations->fs_path.ncomponents <= 0) 242 goto out_free; 243 244 mnt = nfs_follow_referral(mnt_parent, dentry, fs_locations); 245 out_free: 246 __free_page(page); 247 kfree(fs_locations); 248 out: 249 dprintk("%s: done\n", __func__); 250 return mnt; 251 } 252