1 /* 2 * Copyright (c) 2012 Bryan Schumaker <bjschuma@netapp.com> 3 */ 4 #include <linux/init.h> 5 #include <linux/module.h> 6 #include <linux/nfs4_mount.h> 7 #include <linux/nfs_fs.h> 8 #include "delegation.h" 9 #include "internal.h" 10 #include "nfs4_fs.h" 11 #include "nfs4idmap.h" 12 #include "dns_resolve.h" 13 #include "pnfs.h" 14 #include "nfs.h" 15 16 #define NFSDBG_FACILITY NFSDBG_VFS 17 18 static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc); 19 static void nfs4_evict_inode(struct inode *inode); 20 static struct dentry *nfs4_remote_mount(struct file_system_type *fs_type, 21 int flags, const char *dev_name, void *raw_data); 22 static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type, 23 int flags, const char *dev_name, void *raw_data); 24 static struct dentry *nfs4_remote_referral_mount(struct file_system_type *fs_type, 25 int flags, const char *dev_name, void *raw_data); 26 27 static struct file_system_type nfs4_remote_fs_type = { 28 .owner = THIS_MODULE, 29 .name = "nfs4", 30 .mount = nfs4_remote_mount, 31 .kill_sb = nfs_kill_super, 32 .fs_flags = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA, 33 }; 34 35 static struct file_system_type nfs4_remote_referral_fs_type = { 36 .owner = THIS_MODULE, 37 .name = "nfs4", 38 .mount = nfs4_remote_referral_mount, 39 .kill_sb = nfs_kill_super, 40 .fs_flags = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA, 41 }; 42 43 struct file_system_type nfs4_referral_fs_type = { 44 .owner = THIS_MODULE, 45 .name = "nfs4", 46 .mount = nfs4_referral_mount, 47 .kill_sb = nfs_kill_super, 48 .fs_flags = FS_RENAME_DOES_D_MOVE|FS_BINARY_MOUNTDATA, 49 }; 50 51 static const struct super_operations nfs4_sops = { 52 .alloc_inode = nfs_alloc_inode, 53 .destroy_inode = nfs_destroy_inode, 54 .write_inode = nfs4_write_inode, 55 .drop_inode = nfs_drop_inode, 56 .statfs = nfs_statfs, 57 .evict_inode = nfs4_evict_inode, 58 .umount_begin = nfs_umount_begin, 59 .show_options = nfs_show_options, 60 .show_devname = nfs_show_devname, 61 .show_path = nfs_show_path, 62 .show_stats = nfs_show_stats, 63 .remount_fs = nfs_remount, 64 }; 65 66 struct nfs_subversion nfs_v4 = { 67 .owner = THIS_MODULE, 68 .nfs_fs = &nfs4_fs_type, 69 .rpc_vers = &nfs_version4, 70 .rpc_ops = &nfs_v4_clientops, 71 .sops = &nfs4_sops, 72 .xattr = nfs4_xattr_handlers, 73 }; 74 75 static int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc) 76 { 77 int ret = nfs_write_inode(inode, wbc); 78 79 if (ret == 0) 80 ret = pnfs_layoutcommit_inode(inode, 81 wbc->sync_mode == WB_SYNC_ALL); 82 return ret; 83 } 84 85 /* 86 * Clean out any remaining NFSv4 state that might be left over due 87 * to open() calls that passed nfs_atomic_lookup, but failed to call 88 * nfs_open(). 89 */ 90 static void nfs4_evict_inode(struct inode *inode) 91 { 92 truncate_inode_pages_final(&inode->i_data); 93 clear_inode(inode); 94 /* If we are holding a delegation, return it! */ 95 nfs_inode_return_delegation_noreclaim(inode); 96 /* Note that above delegreturn would trigger pnfs return-on-close */ 97 pnfs_return_layout(inode); 98 pnfs_destroy_layout(NFS_I(inode)); 99 /* First call standard NFS clear_inode() code */ 100 nfs_clear_inode(inode); 101 } 102 103 /* 104 * Get the superblock for the NFS4 root partition 105 */ 106 static struct dentry * 107 nfs4_remote_mount(struct file_system_type *fs_type, int flags, 108 const char *dev_name, void *info) 109 { 110 struct nfs_mount_info *mount_info = info; 111 struct nfs_server *server; 112 struct dentry *mntroot = ERR_PTR(-ENOMEM); 113 114 mount_info->set_security = nfs_set_sb_security; 115 116 /* Get a volume representation */ 117 server = nfs4_create_server(mount_info, &nfs_v4); 118 if (IS_ERR(server)) { 119 mntroot = ERR_CAST(server); 120 goto out; 121 } 122 123 mntroot = nfs_fs_mount_common(server, flags, dev_name, mount_info, &nfs_v4); 124 125 out: 126 return mntroot; 127 } 128 129 static struct vfsmount *nfs_do_root_mount(struct file_system_type *fs_type, 130 int flags, void *data, const char *hostname) 131 { 132 struct vfsmount *root_mnt; 133 char *root_devname; 134 size_t len; 135 136 len = strlen(hostname) + 5; 137 root_devname = kmalloc(len, GFP_KERNEL); 138 if (root_devname == NULL) 139 return ERR_PTR(-ENOMEM); 140 /* Does hostname needs to be enclosed in brackets? */ 141 if (strchr(hostname, ':')) 142 snprintf(root_devname, len, "[%s]:/", hostname); 143 else 144 snprintf(root_devname, len, "%s:/", hostname); 145 root_mnt = vfs_kern_mount(fs_type, flags, root_devname, data); 146 kfree(root_devname); 147 return root_mnt; 148 } 149 150 struct nfs_referral_count { 151 struct list_head list; 152 const struct task_struct *task; 153 unsigned int referral_count; 154 }; 155 156 static LIST_HEAD(nfs_referral_count_list); 157 static DEFINE_SPINLOCK(nfs_referral_count_list_lock); 158 159 static struct nfs_referral_count *nfs_find_referral_count(void) 160 { 161 struct nfs_referral_count *p; 162 163 list_for_each_entry(p, &nfs_referral_count_list, list) { 164 if (p->task == current) 165 return p; 166 } 167 return NULL; 168 } 169 170 #define NFS_MAX_NESTED_REFERRALS 2 171 172 static int nfs_referral_loop_protect(void) 173 { 174 struct nfs_referral_count *p, *new; 175 int ret = -ENOMEM; 176 177 new = kmalloc(sizeof(*new), GFP_KERNEL); 178 if (!new) 179 goto out; 180 new->task = current; 181 new->referral_count = 1; 182 183 ret = 0; 184 spin_lock(&nfs_referral_count_list_lock); 185 p = nfs_find_referral_count(); 186 if (p != NULL) { 187 if (p->referral_count >= NFS_MAX_NESTED_REFERRALS) 188 ret = -ELOOP; 189 else 190 p->referral_count++; 191 } else { 192 list_add(&new->list, &nfs_referral_count_list); 193 new = NULL; 194 } 195 spin_unlock(&nfs_referral_count_list_lock); 196 kfree(new); 197 out: 198 return ret; 199 } 200 201 static void nfs_referral_loop_unprotect(void) 202 { 203 struct nfs_referral_count *p; 204 205 spin_lock(&nfs_referral_count_list_lock); 206 p = nfs_find_referral_count(); 207 p->referral_count--; 208 if (p->referral_count == 0) 209 list_del(&p->list); 210 else 211 p = NULL; 212 spin_unlock(&nfs_referral_count_list_lock); 213 kfree(p); 214 } 215 216 static struct dentry *nfs_follow_remote_path(struct vfsmount *root_mnt, 217 const char *export_path) 218 { 219 struct dentry *dentry; 220 int err; 221 222 if (IS_ERR(root_mnt)) 223 return ERR_CAST(root_mnt); 224 225 err = nfs_referral_loop_protect(); 226 if (err) { 227 mntput(root_mnt); 228 return ERR_PTR(err); 229 } 230 231 dentry = mount_subtree(root_mnt, export_path); 232 nfs_referral_loop_unprotect(); 233 234 return dentry; 235 } 236 237 struct dentry *nfs4_try_mount(int flags, const char *dev_name, 238 struct nfs_mount_info *mount_info, 239 struct nfs_subversion *nfs_mod) 240 { 241 char *export_path; 242 struct vfsmount *root_mnt; 243 struct dentry *res; 244 struct nfs_parsed_mount_data *data = mount_info->parsed; 245 246 dfprintk(MOUNT, "--> nfs4_try_mount()\n"); 247 248 export_path = data->nfs_server.export_path; 249 data->nfs_server.export_path = "/"; 250 root_mnt = nfs_do_root_mount(&nfs4_remote_fs_type, flags, mount_info, 251 data->nfs_server.hostname); 252 data->nfs_server.export_path = export_path; 253 254 res = nfs_follow_remote_path(root_mnt, export_path); 255 256 dfprintk(MOUNT, "<-- nfs4_try_mount() = %d%s\n", 257 PTR_ERR_OR_ZERO(res), 258 IS_ERR(res) ? " [error]" : ""); 259 return res; 260 } 261 262 static struct dentry * 263 nfs4_remote_referral_mount(struct file_system_type *fs_type, int flags, 264 const char *dev_name, void *raw_data) 265 { 266 struct nfs_mount_info mount_info = { 267 .fill_super = nfs_fill_super, 268 .set_security = nfs_clone_sb_security, 269 .cloned = raw_data, 270 }; 271 struct nfs_server *server; 272 struct dentry *mntroot = ERR_PTR(-ENOMEM); 273 274 dprintk("--> nfs4_referral_get_sb()\n"); 275 276 mount_info.mntfh = nfs_alloc_fhandle(); 277 if (mount_info.cloned == NULL || mount_info.mntfh == NULL) 278 goto out; 279 280 /* create a new volume representation */ 281 server = nfs4_create_referral_server(mount_info.cloned, mount_info.mntfh); 282 if (IS_ERR(server)) { 283 mntroot = ERR_CAST(server); 284 goto out; 285 } 286 287 mntroot = nfs_fs_mount_common(server, flags, dev_name, &mount_info, &nfs_v4); 288 out: 289 nfs_free_fhandle(mount_info.mntfh); 290 return mntroot; 291 } 292 293 /* 294 * Create an NFS4 server record on referral traversal 295 */ 296 static struct dentry *nfs4_referral_mount(struct file_system_type *fs_type, 297 int flags, const char *dev_name, void *raw_data) 298 { 299 struct nfs_clone_mount *data = raw_data; 300 char *export_path; 301 struct vfsmount *root_mnt; 302 struct dentry *res; 303 304 dprintk("--> nfs4_referral_mount()\n"); 305 306 export_path = data->mnt_path; 307 data->mnt_path = "/"; 308 309 root_mnt = nfs_do_root_mount(&nfs4_remote_referral_fs_type, 310 flags, data, data->hostname); 311 data->mnt_path = export_path; 312 313 res = nfs_follow_remote_path(root_mnt, export_path); 314 dprintk("<-- nfs4_referral_mount() = %d%s\n", 315 PTR_ERR_OR_ZERO(res), 316 IS_ERR(res) ? " [error]" : ""); 317 return res; 318 } 319 320 321 static int __init init_nfs_v4(void) 322 { 323 int err; 324 325 err = nfs_dns_resolver_init(); 326 if (err) 327 goto out; 328 329 err = nfs_idmap_init(); 330 if (err) 331 goto out1; 332 333 err = nfs4_register_sysctl(); 334 if (err) 335 goto out2; 336 337 register_nfs_version(&nfs_v4); 338 return 0; 339 out2: 340 nfs_idmap_quit(); 341 out1: 342 nfs_dns_resolver_destroy(); 343 out: 344 return err; 345 } 346 347 static void __exit exit_nfs_v4(void) 348 { 349 /* Not called in the _init(), conditionally loaded */ 350 nfs4_pnfs_v3_ds_connect_unload(); 351 352 unregister_nfs_version(&nfs_v4); 353 nfs4_unregister_sysctl(); 354 nfs_idmap_quit(); 355 nfs_dns_resolver_destroy(); 356 } 357 358 MODULE_LICENSE("GPL"); 359 360 module_init(init_nfs_v4); 361 module_exit(exit_nfs_v4); 362