1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/ceph/ceph_debug.h> 3 4 #include <linux/file.h> 5 #include <linux/namei.h> 6 #include <linux/random.h> 7 8 #include "super.h" 9 #include "mds_client.h" 10 #include <linux/ceph/pagelist.h> 11 12 static u64 lock_secret; 13 static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc, 14 struct ceph_mds_request *req); 15 16 static inline u64 secure_addr(void *addr) 17 { 18 u64 v = lock_secret ^ (u64)(unsigned long)addr; 19 /* 20 * Set the most significant bit, so that MDS knows the 'owner' 21 * is sufficient to identify the owner of lock. (old code uses 22 * both 'owner' and 'pid') 23 */ 24 v |= (1ULL << 63); 25 return v; 26 } 27 28 void __init ceph_flock_init(void) 29 { 30 get_random_bytes(&lock_secret, sizeof(lock_secret)); 31 } 32 33 static void ceph_fl_copy_lock(struct file_lock *dst, struct file_lock *src) 34 { 35 struct inode *inode = file_inode(src->fl_file); 36 atomic_inc(&ceph_inode(inode)->i_filelock_ref); 37 } 38 39 static void ceph_fl_release_lock(struct file_lock *fl) 40 { 41 struct inode *inode = file_inode(fl->fl_file); 42 atomic_dec(&ceph_inode(inode)->i_filelock_ref); 43 } 44 45 static const struct file_lock_operations ceph_fl_lock_ops = { 46 .fl_copy_lock = ceph_fl_copy_lock, 47 .fl_release_private = ceph_fl_release_lock, 48 }; 49 50 /** 51 * Implement fcntl and flock locking functions. 52 */ 53 static int ceph_lock_message(u8 lock_type, u16 operation, struct inode *inode, 54 int cmd, u8 wait, struct file_lock *fl) 55 { 56 struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc; 57 struct ceph_mds_request *req; 58 int err; 59 u64 length = 0; 60 u64 owner; 61 62 if (operation == CEPH_MDS_OP_SETFILELOCK) { 63 /* 64 * increasing i_filelock_ref closes race window between 65 * handling request reply and adding file_lock struct to 66 * inode. Otherwise, auth caps may get trimmed in the 67 * window. Caller function will decrease the counter. 68 */ 69 fl->fl_ops = &ceph_fl_lock_ops; 70 atomic_inc(&ceph_inode(inode)->i_filelock_ref); 71 } 72 73 if (operation != CEPH_MDS_OP_SETFILELOCK || cmd == CEPH_LOCK_UNLOCK) 74 wait = 0; 75 76 req = ceph_mdsc_create_request(mdsc, operation, USE_AUTH_MDS); 77 if (IS_ERR(req)) 78 return PTR_ERR(req); 79 req->r_inode = inode; 80 ihold(inode); 81 req->r_num_caps = 1; 82 83 /* mds requires start and length rather than start and end */ 84 if (LLONG_MAX == fl->fl_end) 85 length = 0; 86 else 87 length = fl->fl_end - fl->fl_start + 1; 88 89 owner = secure_addr(fl->fl_owner); 90 91 dout("ceph_lock_message: rule: %d, op: %d, owner: %llx, pid: %llu, " 92 "start: %llu, length: %llu, wait: %d, type: %d", (int)lock_type, 93 (int)operation, owner, (u64)fl->fl_pid, fl->fl_start, length, 94 wait, fl->fl_type); 95 96 req->r_args.filelock_change.rule = lock_type; 97 req->r_args.filelock_change.type = cmd; 98 req->r_args.filelock_change.owner = cpu_to_le64(owner); 99 req->r_args.filelock_change.pid = cpu_to_le64((u64)fl->fl_pid); 100 req->r_args.filelock_change.start = cpu_to_le64(fl->fl_start); 101 req->r_args.filelock_change.length = cpu_to_le64(length); 102 req->r_args.filelock_change.wait = wait; 103 104 if (wait) 105 req->r_wait_for_completion = ceph_lock_wait_for_completion; 106 107 err = ceph_mdsc_do_request(mdsc, inode, req); 108 109 if (operation == CEPH_MDS_OP_GETFILELOCK) { 110 fl->fl_pid = -le64_to_cpu(req->r_reply_info.filelock_reply->pid); 111 if (CEPH_LOCK_SHARED == req->r_reply_info.filelock_reply->type) 112 fl->fl_type = F_RDLCK; 113 else if (CEPH_LOCK_EXCL == req->r_reply_info.filelock_reply->type) 114 fl->fl_type = F_WRLCK; 115 else 116 fl->fl_type = F_UNLCK; 117 118 fl->fl_start = le64_to_cpu(req->r_reply_info.filelock_reply->start); 119 length = le64_to_cpu(req->r_reply_info.filelock_reply->start) + 120 le64_to_cpu(req->r_reply_info.filelock_reply->length); 121 if (length >= 1) 122 fl->fl_end = length -1; 123 else 124 fl->fl_end = 0; 125 126 } 127 ceph_mdsc_put_request(req); 128 dout("ceph_lock_message: rule: %d, op: %d, pid: %llu, start: %llu, " 129 "length: %llu, wait: %d, type: %d, err code %d", (int)lock_type, 130 (int)operation, (u64)fl->fl_pid, fl->fl_start, 131 length, wait, fl->fl_type, err); 132 return err; 133 } 134 135 static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc, 136 struct ceph_mds_request *req) 137 { 138 struct ceph_mds_request *intr_req; 139 struct inode *inode = req->r_inode; 140 int err, lock_type; 141 142 BUG_ON(req->r_op != CEPH_MDS_OP_SETFILELOCK); 143 if (req->r_args.filelock_change.rule == CEPH_LOCK_FCNTL) 144 lock_type = CEPH_LOCK_FCNTL_INTR; 145 else if (req->r_args.filelock_change.rule == CEPH_LOCK_FLOCK) 146 lock_type = CEPH_LOCK_FLOCK_INTR; 147 else 148 BUG_ON(1); 149 BUG_ON(req->r_args.filelock_change.type == CEPH_LOCK_UNLOCK); 150 151 err = wait_for_completion_interruptible(&req->r_completion); 152 if (!err) 153 return 0; 154 155 dout("ceph_lock_wait_for_completion: request %llu was interrupted\n", 156 req->r_tid); 157 158 mutex_lock(&mdsc->mutex); 159 if (test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags)) { 160 err = 0; 161 } else { 162 /* 163 * ensure we aren't running concurrently with 164 * ceph_fill_trace or ceph_readdir_prepopulate, which 165 * rely on locks (dir mutex) held by our caller. 166 */ 167 mutex_lock(&req->r_fill_mutex); 168 req->r_err = err; 169 set_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags); 170 mutex_unlock(&req->r_fill_mutex); 171 172 if (!req->r_session) { 173 // haven't sent the request 174 err = 0; 175 } 176 } 177 mutex_unlock(&mdsc->mutex); 178 if (!err) 179 return 0; 180 181 intr_req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SETFILELOCK, 182 USE_AUTH_MDS); 183 if (IS_ERR(intr_req)) 184 return PTR_ERR(intr_req); 185 186 intr_req->r_inode = inode; 187 ihold(inode); 188 intr_req->r_num_caps = 1; 189 190 intr_req->r_args.filelock_change = req->r_args.filelock_change; 191 intr_req->r_args.filelock_change.rule = lock_type; 192 intr_req->r_args.filelock_change.type = CEPH_LOCK_UNLOCK; 193 194 err = ceph_mdsc_do_request(mdsc, inode, intr_req); 195 ceph_mdsc_put_request(intr_req); 196 197 if (err && err != -ERESTARTSYS) 198 return err; 199 200 wait_for_completion_killable(&req->r_safe_completion); 201 return 0; 202 } 203 204 /** 205 * Attempt to set an fcntl lock. 206 * For now, this just goes away to the server. Later it may be more awesome. 207 */ 208 int ceph_lock(struct file *file, int cmd, struct file_lock *fl) 209 { 210 struct inode *inode = file_inode(file); 211 int err; 212 u16 op = CEPH_MDS_OP_SETFILELOCK; 213 u8 lock_cmd; 214 u8 wait = 0; 215 216 if (!(fl->fl_flags & FL_POSIX)) 217 return -ENOLCK; 218 /* No mandatory locks */ 219 if (__mandatory_lock(file->f_mapping->host) && fl->fl_type != F_UNLCK) 220 return -ENOLCK; 221 222 dout("ceph_lock, fl_owner: %p", fl->fl_owner); 223 224 /* set wait bit as appropriate, then make command as Ceph expects it*/ 225 if (IS_GETLK(cmd)) 226 op = CEPH_MDS_OP_GETFILELOCK; 227 else if (IS_SETLKW(cmd)) 228 wait = 1; 229 230 if (op == CEPH_MDS_OP_SETFILELOCK) { 231 /* 232 * increasing i_filelock_ref closes race window between 233 * handling request reply and adding file_lock struct to 234 * inode. Otherwise, i_auth_cap may get trimmed in the 235 * window. Caller function will decrease the counter. 236 */ 237 fl->fl_ops = &ceph_fl_lock_ops; 238 atomic_inc(&ceph_inode(inode)->i_filelock_ref); 239 } 240 241 if (F_RDLCK == fl->fl_type) 242 lock_cmd = CEPH_LOCK_SHARED; 243 else if (F_WRLCK == fl->fl_type) 244 lock_cmd = CEPH_LOCK_EXCL; 245 else 246 lock_cmd = CEPH_LOCK_UNLOCK; 247 248 err = ceph_lock_message(CEPH_LOCK_FCNTL, op, inode, lock_cmd, wait, fl); 249 if (!err) { 250 if (op != CEPH_MDS_OP_GETFILELOCK) { 251 dout("mds locked, locking locally"); 252 err = posix_lock_file(file, fl, NULL); 253 if (err && (CEPH_MDS_OP_SETFILELOCK == op)) { 254 /* undo! This should only happen if 255 * the kernel detects local 256 * deadlock. */ 257 ceph_lock_message(CEPH_LOCK_FCNTL, op, inode, 258 CEPH_LOCK_UNLOCK, 0, fl); 259 dout("got %d on posix_lock_file, undid lock", 260 err); 261 } 262 } 263 } 264 return err; 265 } 266 267 int ceph_flock(struct file *file, int cmd, struct file_lock *fl) 268 { 269 struct inode *inode = file_inode(file); 270 int err; 271 u8 lock_cmd; 272 u8 wait = 0; 273 274 if (!(fl->fl_flags & FL_FLOCK)) 275 return -ENOLCK; 276 /* No mandatory locks */ 277 if (fl->fl_type & LOCK_MAND) 278 return -EOPNOTSUPP; 279 280 dout("ceph_flock, fl_file: %p", fl->fl_file); 281 282 /* see comment in ceph_lock */ 283 fl->fl_ops = &ceph_fl_lock_ops; 284 atomic_inc(&ceph_inode(inode)->i_filelock_ref); 285 286 if (IS_SETLKW(cmd)) 287 wait = 1; 288 289 if (F_RDLCK == fl->fl_type) 290 lock_cmd = CEPH_LOCK_SHARED; 291 else if (F_WRLCK == fl->fl_type) 292 lock_cmd = CEPH_LOCK_EXCL; 293 else 294 lock_cmd = CEPH_LOCK_UNLOCK; 295 296 err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK, 297 inode, lock_cmd, wait, fl); 298 if (!err) { 299 err = locks_lock_file_wait(file, fl); 300 if (err) { 301 ceph_lock_message(CEPH_LOCK_FLOCK, 302 CEPH_MDS_OP_SETFILELOCK, 303 inode, CEPH_LOCK_UNLOCK, 0, fl); 304 dout("got %d on locks_lock_file_wait, undid lock", err); 305 } 306 } 307 return err; 308 } 309 310 /* 311 * Fills in the passed counter variables, so you can prepare pagelist metadata 312 * before calling ceph_encode_locks. 313 */ 314 void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count) 315 { 316 struct file_lock *lock; 317 struct file_lock_context *ctx; 318 319 *fcntl_count = 0; 320 *flock_count = 0; 321 322 ctx = inode->i_flctx; 323 if (ctx) { 324 spin_lock(&ctx->flc_lock); 325 list_for_each_entry(lock, &ctx->flc_posix, fl_list) 326 ++(*fcntl_count); 327 list_for_each_entry(lock, &ctx->flc_flock, fl_list) 328 ++(*flock_count); 329 spin_unlock(&ctx->flc_lock); 330 } 331 dout("counted %d flock locks and %d fcntl locks", 332 *flock_count, *fcntl_count); 333 } 334 335 /** 336 * Encode the flock and fcntl locks for the given inode into the ceph_filelock 337 * array. Must be called with inode->i_lock already held. 338 * If we encounter more of a specific lock type than expected, return -ENOSPC. 339 */ 340 int ceph_encode_locks_to_buffer(struct inode *inode, 341 struct ceph_filelock *flocks, 342 int num_fcntl_locks, int num_flock_locks) 343 { 344 struct file_lock *lock; 345 struct file_lock_context *ctx = inode->i_flctx; 346 int err = 0; 347 int seen_fcntl = 0; 348 int seen_flock = 0; 349 int l = 0; 350 351 dout("encoding %d flock and %d fcntl locks", num_flock_locks, 352 num_fcntl_locks); 353 354 if (!ctx) 355 return 0; 356 357 spin_lock(&ctx->flc_lock); 358 list_for_each_entry(lock, &ctx->flc_posix, fl_list) { 359 ++seen_fcntl; 360 if (seen_fcntl > num_fcntl_locks) { 361 err = -ENOSPC; 362 goto fail; 363 } 364 err = lock_to_ceph_filelock(lock, &flocks[l]); 365 if (err) 366 goto fail; 367 ++l; 368 } 369 list_for_each_entry(lock, &ctx->flc_flock, fl_list) { 370 ++seen_flock; 371 if (seen_flock > num_flock_locks) { 372 err = -ENOSPC; 373 goto fail; 374 } 375 err = lock_to_ceph_filelock(lock, &flocks[l]); 376 if (err) 377 goto fail; 378 ++l; 379 } 380 fail: 381 spin_unlock(&ctx->flc_lock); 382 return err; 383 } 384 385 /** 386 * Copy the encoded flock and fcntl locks into the pagelist. 387 * Format is: #fcntl locks, sequential fcntl locks, #flock locks, 388 * sequential flock locks. 389 * Returns zero on success. 390 */ 391 int ceph_locks_to_pagelist(struct ceph_filelock *flocks, 392 struct ceph_pagelist *pagelist, 393 int num_fcntl_locks, int num_flock_locks) 394 { 395 int err = 0; 396 __le32 nlocks; 397 398 nlocks = cpu_to_le32(num_fcntl_locks); 399 err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks)); 400 if (err) 401 goto out_fail; 402 403 err = ceph_pagelist_append(pagelist, flocks, 404 num_fcntl_locks * sizeof(*flocks)); 405 if (err) 406 goto out_fail; 407 408 nlocks = cpu_to_le32(num_flock_locks); 409 err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks)); 410 if (err) 411 goto out_fail; 412 413 err = ceph_pagelist_append(pagelist, 414 &flocks[num_fcntl_locks], 415 num_flock_locks * sizeof(*flocks)); 416 out_fail: 417 return err; 418 } 419 420 /* 421 * Given a pointer to a lock, convert it to a ceph filelock 422 */ 423 int lock_to_ceph_filelock(struct file_lock *lock, 424 struct ceph_filelock *cephlock) 425 { 426 int err = 0; 427 cephlock->start = cpu_to_le64(lock->fl_start); 428 cephlock->length = cpu_to_le64(lock->fl_end - lock->fl_start + 1); 429 cephlock->client = cpu_to_le64(0); 430 cephlock->pid = cpu_to_le64((u64)lock->fl_pid); 431 cephlock->owner = cpu_to_le64(secure_addr(lock->fl_owner)); 432 433 switch (lock->fl_type) { 434 case F_RDLCK: 435 cephlock->type = CEPH_LOCK_SHARED; 436 break; 437 case F_WRLCK: 438 cephlock->type = CEPH_LOCK_EXCL; 439 break; 440 case F_UNLCK: 441 cephlock->type = CEPH_LOCK_UNLOCK; 442 break; 443 default: 444 dout("Have unknown lock type %d", lock->fl_type); 445 err = -EINVAL; 446 } 447 448 return err; 449 } 450