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