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 5 29 #define FILE_NRHASH (1<<FILE_HASH_BITS) 30 static struct nlm_file * 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_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 u32 82 nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result, 83 struct nfs_fh *f) 84 { 85 struct nlm_file *file; 86 unsigned int hash; 87 u32 nfserr; 88 89 nlm_debug_print_fh("nlm_file_lookup", f); 90 91 hash = file_hash(f); 92 93 /* Lock file table */ 94 mutex_lock(&nlm_file_mutex); 95 96 for (file = nlm_files[hash]; file; file = file->f_next) 97 if (!nfs_compare_fh(&file->f_handle, f)) 98 goto found; 99 100 nlm_debug_print_fh("creating file for", f); 101 102 nfserr = nlm_lck_denied_nolocks; 103 file = (struct nlm_file *) kmalloc(sizeof(*file), GFP_KERNEL); 104 if (!file) 105 goto out_unlock; 106 107 memset(file, 0, sizeof(*file)); 108 memcpy(&file->f_handle, f, sizeof(struct nfs_fh)); 109 file->f_hash = hash; 110 init_MUTEX(&file->f_sema); 111 112 /* Open the file. Note that this must not sleep for too long, else 113 * we would lock up lockd:-) So no NFS re-exports, folks. 114 * 115 * We have to make sure we have the right credential to open 116 * the file. 117 */ 118 if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) { 119 dprintk("lockd: open failed (nfserr %d)\n", ntohl(nfserr)); 120 goto out_free; 121 } 122 123 file->f_next = nlm_files[hash]; 124 nlm_files[hash] = file; 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 #ifdef CONFIG_LOCKD_V4 139 if (nfserr == 1) 140 nfserr = nlm4_stale_fh; 141 else 142 #endif 143 nfserr = nlm_lck_denied; 144 goto out_unlock; 145 } 146 147 /* 148 * Delete a file after having released all locks, blocks and shares 149 */ 150 static inline void 151 nlm_delete_file(struct nlm_file *file) 152 { 153 struct nlm_file **fp, *f; 154 155 nlm_debug_print_file("closing file", file); 156 157 fp = nlm_files + file->f_hash; 158 while ((f = *fp) != NULL) { 159 if (f == file) { 160 *fp = file->f_next; 161 nlmsvc_ops->fclose(file->f_file); 162 kfree(file); 163 return; 164 } 165 fp = &f->f_next; 166 } 167 168 printk(KERN_WARNING "lockd: attempt to release unknown file!\n"); 169 } 170 171 /* 172 * Loop over all locks on the given file and perform the specified 173 * action. 174 */ 175 static int 176 nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file, int action) 177 { 178 struct inode *inode = nlmsvc_file_inode(file); 179 struct file_lock *fl; 180 struct nlm_host *lockhost; 181 182 again: 183 file->f_locks = 0; 184 for (fl = inode->i_flock; fl; fl = fl->fl_next) { 185 if (fl->fl_lmops != &nlmsvc_lock_operations) 186 continue; 187 188 /* update current lock count */ 189 file->f_locks++; 190 lockhost = (struct nlm_host *) fl->fl_owner; 191 if (action == NLM_ACT_MARK) 192 lockhost->h_inuse = 1; 193 else if (action == NLM_ACT_CHECK) 194 return 1; 195 else if (action == NLM_ACT_UNLOCK) { 196 struct file_lock lock = *fl; 197 198 if (host && lockhost != host) 199 continue; 200 201 lock.fl_type = F_UNLCK; 202 lock.fl_start = 0; 203 lock.fl_end = OFFSET_MAX; 204 if (posix_lock_file(file->f_file, &lock) < 0) { 205 printk("lockd: unlock failure in %s:%d\n", 206 __FILE__, __LINE__); 207 return 1; 208 } 209 goto again; 210 } 211 } 212 213 return 0; 214 } 215 216 /* 217 * Operate on a single file 218 */ 219 static inline int 220 nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, int action) 221 { 222 if (action == NLM_ACT_CHECK) { 223 /* Fast path for mark and sweep garbage collection */ 224 if (file->f_count || file->f_blocks || file->f_shares) 225 return 1; 226 } else { 227 nlmsvc_traverse_blocks(host, file, action); 228 nlmsvc_traverse_shares(host, file, action); 229 } 230 return nlm_traverse_locks(host, file, action); 231 } 232 233 /* 234 * Loop over all files in the file table. 235 */ 236 static int 237 nlm_traverse_files(struct nlm_host *host, int action) 238 { 239 struct nlm_file *file, **fp; 240 int i; 241 242 mutex_lock(&nlm_file_mutex); 243 for (i = 0; i < FILE_NRHASH; i++) { 244 fp = nlm_files + i; 245 while ((file = *fp) != NULL) { 246 /* Traverse locks, blocks and shares of this file 247 * and update file->f_locks count */ 248 if (nlm_inspect_file(host, file, action)) { 249 mutex_unlock(&nlm_file_mutex); 250 return 1; 251 } 252 253 /* No more references to this file. Let go of it. */ 254 if (!file->f_blocks && !file->f_locks 255 && !file->f_shares && !file->f_count) { 256 *fp = file->f_next; 257 nlmsvc_ops->fclose(file->f_file); 258 kfree(file); 259 } else { 260 fp = &file->f_next; 261 } 262 } 263 } 264 mutex_unlock(&nlm_file_mutex); 265 return 0; 266 } 267 268 /* 269 * Release file. If there are no more remote locks on this file, 270 * close it and free the handle. 271 * 272 * Note that we can't do proper reference counting without major 273 * contortions because the code in fs/locks.c creates, deletes and 274 * splits locks without notification. Our only way is to walk the 275 * entire lock list each time we remove a lock. 276 */ 277 void 278 nlm_release_file(struct nlm_file *file) 279 { 280 dprintk("lockd: nlm_release_file(%p, ct = %d)\n", 281 file, file->f_count); 282 283 /* Lock file table */ 284 mutex_lock(&nlm_file_mutex); 285 286 /* If there are no more locks etc, delete the file */ 287 if(--file->f_count == 0) { 288 if(!nlm_inspect_file(NULL, file, NLM_ACT_CHECK)) 289 nlm_delete_file(file); 290 } 291 292 mutex_unlock(&nlm_file_mutex); 293 } 294 295 /* 296 * Mark all hosts that still hold resources 297 */ 298 void 299 nlmsvc_mark_resources(void) 300 { 301 dprintk("lockd: nlmsvc_mark_resources\n"); 302 303 nlm_traverse_files(NULL, NLM_ACT_MARK); 304 } 305 306 /* 307 * Release all resources held by the given client 308 */ 309 void 310 nlmsvc_free_host_resources(struct nlm_host *host) 311 { 312 dprintk("lockd: nlmsvc_free_host_resources\n"); 313 314 if (nlm_traverse_files(host, NLM_ACT_UNLOCK)) 315 printk(KERN_WARNING 316 "lockd: couldn't remove all locks held by %s", 317 host->h_name); 318 } 319 320 /* 321 * delete all hosts structs for clients 322 */ 323 void 324 nlmsvc_invalidate_all(void) 325 { 326 struct nlm_host *host; 327 while ((host = nlm_find_client()) != NULL) { 328 nlmsvc_free_host_resources(host); 329 host->h_expires = 0; 330 host->h_killed = 1; 331 nlm_release_host(host); 332 } 333 } 334