1 /* 2 * linux/fs/lockd/svcsubs.c 3 * 4 * Various support routines for the NLM server. 5 * 6 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> 7 */ 8 9 #include <linux/types.h> 10 #include <linux/string.h> 11 #include <linux/time.h> 12 #include <linux/in.h> 13 #include <linux/slab.h> 14 #include <linux/mutex.h> 15 #include <linux/sunrpc/svc.h> 16 #include <linux/sunrpc/clnt.h> 17 #include <linux/nfsd/nfsfh.h> 18 #include <linux/nfsd/export.h> 19 #include <linux/lockd/lockd.h> 20 #include <linux/lockd/share.h> 21 #include <linux/module.h> 22 #include <linux/mount.h> 23 24 #define NLMDBG_FACILITY NLMDBG_SVCSUBS 25 26 27 /* 28 * Global file hash table 29 */ 30 #define FILE_HASH_BITS 7 31 #define FILE_NRHASH (1<<FILE_HASH_BITS) 32 static struct hlist_head nlm_files[FILE_NRHASH]; 33 static DEFINE_MUTEX(nlm_file_mutex); 34 35 #ifdef NFSD_DEBUG 36 static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f) 37 { 38 u32 *fhp = (u32*)f->data; 39 40 /* print the first 32 bytes of the fh */ 41 dprintk("lockd: %s (%08x %08x %08x %08x %08x %08x %08x %08x)\n", 42 msg, fhp[0], fhp[1], fhp[2], fhp[3], 43 fhp[4], fhp[5], fhp[6], fhp[7]); 44 } 45 46 static inline void nlm_debug_print_file(char *msg, struct nlm_file *file) 47 { 48 struct inode *inode = file->f_file->f_path.dentry->d_inode; 49 50 dprintk("lockd: %s %s/%ld\n", 51 msg, inode->i_sb->s_id, inode->i_ino); 52 } 53 #else 54 static inline void nlm_debug_print_fh(char *msg, struct nfs_fh *f) 55 { 56 return; 57 } 58 59 static inline void nlm_debug_print_file(char *msg, struct nlm_file *file) 60 { 61 return; 62 } 63 #endif 64 65 static inline unsigned int file_hash(struct nfs_fh *f) 66 { 67 unsigned int tmp=0; 68 int i; 69 for (i=0; i<NFS2_FHSIZE;i++) 70 tmp += f->data[i]; 71 return tmp & (FILE_NRHASH - 1); 72 } 73 74 /* 75 * Lookup file info. If it doesn't exist, create a file info struct 76 * and open a (VFS) file for the given inode. 77 * 78 * FIXME: 79 * Note that we open the file O_RDONLY even when creating write locks. 80 * This is not quite right, but for now, we assume the client performs 81 * the proper R/W checking. 82 */ 83 __be32 84 nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result, 85 struct nfs_fh *f) 86 { 87 struct hlist_node *pos; 88 struct nlm_file *file; 89 unsigned int hash; 90 __be32 nfserr; 91 92 nlm_debug_print_fh("nlm_lookup_file", f); 93 94 hash = file_hash(f); 95 96 /* Lock file table */ 97 mutex_lock(&nlm_file_mutex); 98 99 hlist_for_each_entry(file, pos, &nlm_files[hash], f_list) 100 if (!nfs_compare_fh(&file->f_handle, f)) 101 goto found; 102 103 nlm_debug_print_fh("creating file for", f); 104 105 nfserr = nlm_lck_denied_nolocks; 106 file = kzalloc(sizeof(*file), GFP_KERNEL); 107 if (!file) 108 goto out_unlock; 109 110 memcpy(&file->f_handle, f, sizeof(struct nfs_fh)); 111 mutex_init(&file->f_mutex); 112 INIT_HLIST_NODE(&file->f_list); 113 INIT_LIST_HEAD(&file->f_blocks); 114 115 /* Open the file. Note that this must not sleep for too long, else 116 * we would lock up lockd:-) So no NFS re-exports, folks. 117 * 118 * We have to make sure we have the right credential to open 119 * the file. 120 */ 121 if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) { 122 dprintk("lockd: open failed (error %d)\n", nfserr); 123 goto out_free; 124 } 125 126 hlist_add_head(&file->f_list, &nlm_files[hash]); 127 128 found: 129 dprintk("lockd: found file %p (count %d)\n", file, file->f_count); 130 *result = file; 131 file->f_count++; 132 nfserr = 0; 133 134 out_unlock: 135 mutex_unlock(&nlm_file_mutex); 136 return nfserr; 137 138 out_free: 139 kfree(file); 140 goto out_unlock; 141 } 142 143 /* 144 * Delete a file after having released all locks, blocks and shares 145 */ 146 static inline void 147 nlm_delete_file(struct nlm_file *file) 148 { 149 nlm_debug_print_file("closing file", file); 150 if (!hlist_unhashed(&file->f_list)) { 151 hlist_del(&file->f_list); 152 nlmsvc_ops->fclose(file->f_file); 153 kfree(file); 154 } else { 155 printk(KERN_WARNING "lockd: attempt to release unknown file!\n"); 156 } 157 } 158 159 /* 160 * Loop over all locks on the given file and perform the specified 161 * action. 162 */ 163 static int 164 nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file, 165 nlm_host_match_fn_t match) 166 { 167 struct inode *inode = nlmsvc_file_inode(file); 168 struct file_lock *fl; 169 struct nlm_host *lockhost; 170 171 again: 172 file->f_locks = 0; 173 lock_flocks(); /* protects i_flock list */ 174 for (fl = inode->i_flock; fl; fl = fl->fl_next) { 175 if (fl->fl_lmops != &nlmsvc_lock_operations) 176 continue; 177 178 /* update current lock count */ 179 file->f_locks++; 180 181 lockhost = (struct nlm_host *) fl->fl_owner; 182 if (match(lockhost, host)) { 183 struct file_lock lock = *fl; 184 185 unlock_flocks(); 186 lock.fl_type = F_UNLCK; 187 lock.fl_start = 0; 188 lock.fl_end = OFFSET_MAX; 189 if (vfs_lock_file(file->f_file, F_SETLK, &lock, NULL) < 0) { 190 printk("lockd: unlock failure in %s:%d\n", 191 __FILE__, __LINE__); 192 return 1; 193 } 194 goto again; 195 } 196 } 197 unlock_flocks(); 198 199 return 0; 200 } 201 202 static int 203 nlmsvc_always_match(void *dummy1, struct nlm_host *dummy2) 204 { 205 return 1; 206 } 207 208 /* 209 * Inspect a single file 210 */ 211 static inline int 212 nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, nlm_host_match_fn_t match) 213 { 214 nlmsvc_traverse_blocks(host, file, match); 215 nlmsvc_traverse_shares(host, file, match); 216 return nlm_traverse_locks(host, file, match); 217 } 218 219 /* 220 * Quick check whether there are still any locks, blocks or 221 * shares on a given file. 222 */ 223 static inline int 224 nlm_file_inuse(struct nlm_file *file) 225 { 226 struct inode *inode = nlmsvc_file_inode(file); 227 struct file_lock *fl; 228 229 if (file->f_count || !list_empty(&file->f_blocks) || file->f_shares) 230 return 1; 231 232 lock_flocks(); 233 for (fl = inode->i_flock; fl; fl = fl->fl_next) { 234 if (fl->fl_lmops == &nlmsvc_lock_operations) { 235 unlock_flocks(); 236 return 1; 237 } 238 } 239 unlock_flocks(); 240 file->f_locks = 0; 241 return 0; 242 } 243 244 /* 245 * Loop over all files in the file table. 246 */ 247 static int 248 nlm_traverse_files(void *data, nlm_host_match_fn_t match, 249 int (*is_failover_file)(void *data, struct nlm_file *file)) 250 { 251 struct hlist_node *pos, *next; 252 struct nlm_file *file; 253 int i, ret = 0; 254 255 mutex_lock(&nlm_file_mutex); 256 for (i = 0; i < FILE_NRHASH; i++) { 257 hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) { 258 if (is_failover_file && !is_failover_file(data, file)) 259 continue; 260 file->f_count++; 261 mutex_unlock(&nlm_file_mutex); 262 263 /* Traverse locks, blocks and shares of this file 264 * and update file->f_locks count */ 265 if (nlm_inspect_file(data, file, match)) 266 ret = 1; 267 268 mutex_lock(&nlm_file_mutex); 269 file->f_count--; 270 /* No more references to this file. Let go of it. */ 271 if (list_empty(&file->f_blocks) && !file->f_locks 272 && !file->f_shares && !file->f_count) { 273 hlist_del(&file->f_list); 274 nlmsvc_ops->fclose(file->f_file); 275 kfree(file); 276 } 277 } 278 } 279 mutex_unlock(&nlm_file_mutex); 280 return ret; 281 } 282 283 /* 284 * Release file. If there are no more remote locks on this file, 285 * close it and free the handle. 286 * 287 * Note that we can't do proper reference counting without major 288 * contortions because the code in fs/locks.c creates, deletes and 289 * splits locks without notification. Our only way is to walk the 290 * entire lock list each time we remove a lock. 291 */ 292 void 293 nlm_release_file(struct nlm_file *file) 294 { 295 dprintk("lockd: nlm_release_file(%p, ct = %d)\n", 296 file, file->f_count); 297 298 /* Lock file table */ 299 mutex_lock(&nlm_file_mutex); 300 301 /* If there are no more locks etc, delete the file */ 302 if (--file->f_count == 0 && !nlm_file_inuse(file)) 303 nlm_delete_file(file); 304 305 mutex_unlock(&nlm_file_mutex); 306 } 307 308 /* 309 * Helpers function for resource traversal 310 * 311 * nlmsvc_mark_host: 312 * used by the garbage collector; simply sets h_inuse only for those 313 * hosts, which passed network check. 314 * Always returns 0. 315 * 316 * nlmsvc_same_host: 317 * returns 1 iff the two hosts match. Used to release 318 * all resources bound to a specific host. 319 * 320 * nlmsvc_is_client: 321 * returns 1 iff the host is a client. 322 * Used by nlmsvc_invalidate_all 323 */ 324 325 static int 326 nlmsvc_mark_host(void *data, struct nlm_host *hint) 327 { 328 struct nlm_host *host = data; 329 330 if ((hint->net == NULL) || 331 (host->net == hint->net)) 332 host->h_inuse = 1; 333 return 0; 334 } 335 336 static int 337 nlmsvc_same_host(void *data, struct nlm_host *other) 338 { 339 struct nlm_host *host = data; 340 341 return host == other; 342 } 343 344 static int 345 nlmsvc_is_client(void *data, struct nlm_host *dummy) 346 { 347 struct nlm_host *host = data; 348 349 if (host->h_server) { 350 /* we are destroying locks even though the client 351 * hasn't asked us too, so don't unmonitor the 352 * client 353 */ 354 if (host->h_nsmhandle) 355 host->h_nsmhandle->sm_sticky = 1; 356 return 1; 357 } else 358 return 0; 359 } 360 361 /* 362 * Mark all hosts that still hold resources 363 */ 364 void 365 nlmsvc_mark_resources(struct net *net) 366 { 367 struct nlm_host hint; 368 369 dprintk("lockd: nlmsvc_mark_resources for net %p\n", net); 370 hint.net = net; 371 nlm_traverse_files(&hint, nlmsvc_mark_host, NULL); 372 } 373 374 /* 375 * Release all resources held by the given client 376 */ 377 void 378 nlmsvc_free_host_resources(struct nlm_host *host) 379 { 380 dprintk("lockd: nlmsvc_free_host_resources\n"); 381 382 if (nlm_traverse_files(host, nlmsvc_same_host, NULL)) { 383 printk(KERN_WARNING 384 "lockd: couldn't remove all locks held by %s\n", 385 host->h_name); 386 BUG(); 387 } 388 } 389 390 /** 391 * nlmsvc_invalidate_all - remove all locks held for clients 392 * 393 * Release all locks held by NFS clients. 394 * 395 */ 396 void 397 nlmsvc_invalidate_all(void) 398 { 399 /* 400 * Previously, the code would call 401 * nlmsvc_free_host_resources for each client in 402 * turn, which is about as inefficient as it gets. 403 * Now we just do it once in nlm_traverse_files. 404 */ 405 nlm_traverse_files(NULL, nlmsvc_is_client, NULL); 406 } 407 408 static int 409 nlmsvc_match_sb(void *datap, struct nlm_file *file) 410 { 411 struct super_block *sb = datap; 412 413 return sb == file->f_file->f_path.dentry->d_sb; 414 } 415 416 /** 417 * nlmsvc_unlock_all_by_sb - release locks held on this file system 418 * @sb: super block 419 * 420 * Release all locks held by clients accessing this file system. 421 */ 422 int 423 nlmsvc_unlock_all_by_sb(struct super_block *sb) 424 { 425 int ret; 426 427 ret = nlm_traverse_files(sb, nlmsvc_always_match, nlmsvc_match_sb); 428 return ret ? -EIO : 0; 429 } 430 EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_sb); 431 432 static int 433 nlmsvc_match_ip(void *datap, struct nlm_host *host) 434 { 435 return rpc_cmp_addr(nlm_srcaddr(host), datap); 436 } 437 438 /** 439 * nlmsvc_unlock_all_by_ip - release local locks by IP address 440 * @server_addr: server's IP address as seen by clients 441 * 442 * Release all locks held by clients accessing this host 443 * via the passed in IP address. 444 */ 445 int 446 nlmsvc_unlock_all_by_ip(struct sockaddr *server_addr) 447 { 448 int ret; 449 450 ret = nlm_traverse_files(server_addr, nlmsvc_match_ip, NULL); 451 return ret ? -EIO : 0; 452 } 453 EXPORT_SYMBOL_GPL(nlmsvc_unlock_all_by_ip); 454