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/config.h> 10 #include <linux/types.h> 11 #include <linux/string.h> 12 #include <linux/time.h> 13 #include <linux/in.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 DECLARE_MUTEX(nlm_file_sema); 32 33 static inline unsigned int file_hash(struct nfs_fh *f) 34 { 35 unsigned int tmp=0; 36 int i; 37 for (i=0; i<NFS2_FHSIZE;i++) 38 tmp += f->data[i]; 39 return tmp & (FILE_NRHASH - 1); 40 } 41 42 /* 43 * Lookup file info. If it doesn't exist, create a file info struct 44 * and open a (VFS) file for the given inode. 45 * 46 * FIXME: 47 * Note that we open the file O_RDONLY even when creating write locks. 48 * This is not quite right, but for now, we assume the client performs 49 * the proper R/W checking. 50 */ 51 u32 52 nlm_lookup_file(struct svc_rqst *rqstp, struct nlm_file **result, 53 struct nfs_fh *f) 54 { 55 struct nlm_file *file; 56 unsigned int hash; 57 u32 nfserr; 58 u32 *fhp = (u32*)f->data; 59 60 dprintk("lockd: nlm_file_lookup(%08x %08x %08x %08x %08x %08x)\n", 61 fhp[0], fhp[1], fhp[2], fhp[3], fhp[4], fhp[5]); 62 63 64 hash = file_hash(f); 65 66 /* Lock file table */ 67 down(&nlm_file_sema); 68 69 for (file = nlm_files[hash]; file; file = file->f_next) 70 if (!nfs_compare_fh(&file->f_handle, f)) 71 goto found; 72 73 dprintk("lockd: creating file for (%08x %08x %08x %08x %08x %08x)\n", 74 fhp[0], fhp[1], fhp[2], fhp[3], fhp[4], fhp[5]); 75 76 nfserr = nlm_lck_denied_nolocks; 77 file = (struct nlm_file *) kmalloc(sizeof(*file), GFP_KERNEL); 78 if (!file) 79 goto out_unlock; 80 81 memset(file, 0, sizeof(*file)); 82 memcpy(&file->f_handle, f, sizeof(struct nfs_fh)); 83 file->f_hash = hash; 84 init_MUTEX(&file->f_sema); 85 86 /* Open the file. Note that this must not sleep for too long, else 87 * we would lock up lockd:-) So no NFS re-exports, folks. 88 * 89 * We have to make sure we have the right credential to open 90 * the file. 91 */ 92 if ((nfserr = nlmsvc_ops->fopen(rqstp, f, &file->f_file)) != 0) { 93 dprintk("lockd: open failed (nfserr %d)\n", ntohl(nfserr)); 94 goto out_free; 95 } 96 97 file->f_next = nlm_files[hash]; 98 nlm_files[hash] = file; 99 100 found: 101 dprintk("lockd: found file %p (count %d)\n", file, file->f_count); 102 *result = file; 103 file->f_count++; 104 nfserr = 0; 105 106 out_unlock: 107 up(&nlm_file_sema); 108 return nfserr; 109 110 out_free: 111 kfree(file); 112 #ifdef CONFIG_LOCKD_V4 113 if (nfserr == 1) 114 nfserr = nlm4_stale_fh; 115 else 116 #endif 117 nfserr = nlm_lck_denied; 118 goto out_unlock; 119 } 120 121 /* 122 * Delete a file after having released all locks, blocks and shares 123 */ 124 static inline void 125 nlm_delete_file(struct nlm_file *file) 126 { 127 struct inode *inode = file->f_file->f_dentry->d_inode; 128 struct nlm_file **fp, *f; 129 130 dprintk("lockd: closing file %s/%ld\n", 131 inode->i_sb->s_id, inode->i_ino); 132 fp = nlm_files + file->f_hash; 133 while ((f = *fp) != NULL) { 134 if (f == file) { 135 *fp = file->f_next; 136 nlmsvc_ops->fclose(file->f_file); 137 kfree(file); 138 return; 139 } 140 fp = &f->f_next; 141 } 142 143 printk(KERN_WARNING "lockd: attempt to release unknown file!\n"); 144 } 145 146 /* 147 * Loop over all locks on the given file and perform the specified 148 * action. 149 */ 150 static int 151 nlm_traverse_locks(struct nlm_host *host, struct nlm_file *file, int action) 152 { 153 struct inode *inode = nlmsvc_file_inode(file); 154 struct file_lock *fl; 155 struct nlm_host *lockhost; 156 157 again: 158 file->f_locks = 0; 159 for (fl = inode->i_flock; fl; fl = fl->fl_next) { 160 if (!(fl->fl_flags & FL_LOCKD)) 161 continue; 162 163 /* update current lock count */ 164 file->f_locks++; 165 lockhost = (struct nlm_host *) fl->fl_owner; 166 if (action == NLM_ACT_MARK) 167 lockhost->h_inuse = 1; 168 else if (action == NLM_ACT_CHECK) 169 return 1; 170 else if (action == NLM_ACT_UNLOCK) { 171 struct file_lock lock = *fl; 172 173 if (host && lockhost != host) 174 continue; 175 176 lock.fl_type = F_UNLCK; 177 lock.fl_start = 0; 178 lock.fl_end = OFFSET_MAX; 179 if (posix_lock_file(file->f_file, &lock) < 0) { 180 printk("lockd: unlock failure in %s:%d\n", 181 __FILE__, __LINE__); 182 return 1; 183 } 184 goto again; 185 } 186 } 187 188 return 0; 189 } 190 191 /* 192 * Operate on a single file 193 */ 194 static inline int 195 nlm_inspect_file(struct nlm_host *host, struct nlm_file *file, int action) 196 { 197 if (action == NLM_ACT_CHECK) { 198 /* Fast path for mark and sweep garbage collection */ 199 if (file->f_count || file->f_blocks || file->f_shares) 200 return 1; 201 } else { 202 if (nlmsvc_traverse_blocks(host, file, action) 203 || nlmsvc_traverse_shares(host, file, action)) 204 return 1; 205 } 206 return nlm_traverse_locks(host, file, action); 207 } 208 209 /* 210 * Loop over all files in the file table. 211 */ 212 static int 213 nlm_traverse_files(struct nlm_host *host, int action) 214 { 215 struct nlm_file *file, **fp; 216 int i; 217 218 down(&nlm_file_sema); 219 for (i = 0; i < FILE_NRHASH; i++) { 220 fp = nlm_files + i; 221 while ((file = *fp) != NULL) { 222 /* Traverse locks, blocks and shares of this file 223 * and update file->f_locks count */ 224 if (nlm_inspect_file(host, file, action)) { 225 up(&nlm_file_sema); 226 return 1; 227 } 228 229 /* No more references to this file. Let go of it. */ 230 if (!file->f_blocks && !file->f_locks 231 && !file->f_shares && !file->f_count) { 232 *fp = file->f_next; 233 nlmsvc_ops->fclose(file->f_file); 234 kfree(file); 235 } else { 236 fp = &file->f_next; 237 } 238 } 239 } 240 up(&nlm_file_sema); 241 return 0; 242 } 243 244 /* 245 * Release file. If there are no more remote locks on this file, 246 * close it and free the handle. 247 * 248 * Note that we can't do proper reference counting without major 249 * contortions because the code in fs/locks.c creates, deletes and 250 * splits locks without notification. Our only way is to walk the 251 * entire lock list each time we remove a lock. 252 */ 253 void 254 nlm_release_file(struct nlm_file *file) 255 { 256 dprintk("lockd: nlm_release_file(%p, ct = %d)\n", 257 file, file->f_count); 258 259 /* Lock file table */ 260 down(&nlm_file_sema); 261 262 /* If there are no more locks etc, delete the file */ 263 if(--file->f_count == 0) { 264 if(!nlm_inspect_file(NULL, file, NLM_ACT_CHECK)) 265 nlm_delete_file(file); 266 } 267 268 up(&nlm_file_sema); 269 } 270 271 /* 272 * Mark all hosts that still hold resources 273 */ 274 void 275 nlmsvc_mark_resources(void) 276 { 277 dprintk("lockd: nlmsvc_mark_resources\n"); 278 279 nlm_traverse_files(NULL, NLM_ACT_MARK); 280 } 281 282 /* 283 * Release all resources held by the given client 284 */ 285 void 286 nlmsvc_free_host_resources(struct nlm_host *host) 287 { 288 dprintk("lockd: nlmsvc_free_host_resources\n"); 289 290 if (nlm_traverse_files(host, NLM_ACT_UNLOCK)) 291 printk(KERN_WARNING 292 "lockd: couldn't remove all locks held by %s", 293 host->h_name); 294 } 295 296 /* 297 * delete all hosts structs for clients 298 */ 299 void 300 nlmsvc_invalidate_all(void) 301 { 302 struct nlm_host *host; 303 while ((host = nlm_find_client()) != NULL) { 304 nlmsvc_free_host_resources(host); 305 host->h_expires = 0; 306 host->h_killed = 1; 307 nlm_release_host(host); 308 } 309 } 310