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/filelock.h> 11 #include <linux/ceph/pagelist.h> 12 13 static u64 lock_secret; 14 static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc, 15 struct ceph_mds_request *req); 16 17 static inline u64 secure_addr(void *addr) 18 { 19 u64 v = lock_secret ^ (u64)(unsigned long)addr; 20 /* 21 * Set the most significant bit, so that MDS knows the 'owner' 22 * is sufficient to identify the owner of lock. (old code uses 23 * both 'owner' and 'pid') 24 */ 25 v |= (1ULL << 63); 26 return v; 27 } 28 29 void __init ceph_flock_init(void) 30 { 31 get_random_bytes(&lock_secret, sizeof(lock_secret)); 32 } 33 34 static void ceph_fl_copy_lock(struct file_lock *dst, struct file_lock *src) 35 { 36 struct inode *inode = file_inode(dst->c.flc_file); 37 atomic_inc(&ceph_inode(inode)->i_filelock_ref); 38 dst->fl_u.ceph.inode = igrab(inode); 39 } 40 41 /* 42 * Do not use the 'fl->fl_file' in release function, which 43 * is possibly already released by another thread. 44 */ 45 static void ceph_fl_release_lock(struct file_lock *fl) 46 { 47 struct inode *inode = fl->fl_u.ceph.inode; 48 struct ceph_inode_info *ci; 49 50 /* 51 * If inode is NULL it should be a request file_lock, 52 * nothing we can do. 53 */ 54 if (!inode) 55 return; 56 57 ci = ceph_inode(inode); 58 if (atomic_dec_and_test(&ci->i_filelock_ref)) { 59 /* clear error when all locks are released */ 60 clear_bit(CEPH_I_ERROR_FILELOCK_BIT, &ci->i_ceph_flags); 61 } 62 fl->fl_u.ceph.inode = NULL; 63 iput(inode); 64 } 65 66 static const struct file_lock_operations ceph_fl_lock_ops = { 67 .fl_copy_lock = ceph_fl_copy_lock, 68 .fl_release_private = ceph_fl_release_lock, 69 }; 70 71 /* 72 * Implement fcntl and flock locking functions. 73 */ 74 static int ceph_lock_message(u8 lock_type, u16 operation, struct inode *inode, 75 int cmd, u8 wait, struct file_lock *fl) 76 { 77 struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb); 78 struct ceph_client *cl = mdsc->fsc->client; 79 struct ceph_mds_request *req; 80 int err; 81 u64 length = 0; 82 u64 owner; 83 84 if (operation == CEPH_MDS_OP_SETFILELOCK) { 85 /* 86 * increasing i_filelock_ref closes race window between 87 * handling request reply and adding file_lock struct to 88 * inode. Otherwise, auth caps may get trimmed in the 89 * window. Caller function will decrease the counter. 90 */ 91 fl->fl_ops = &ceph_fl_lock_ops; 92 fl->fl_ops->fl_copy_lock(fl, NULL); 93 } 94 95 if (operation != CEPH_MDS_OP_SETFILELOCK || cmd == CEPH_LOCK_UNLOCK) 96 wait = 0; 97 98 req = ceph_mdsc_create_request(mdsc, operation, USE_AUTH_MDS); 99 if (IS_ERR(req)) 100 return PTR_ERR(req); 101 req->r_inode = inode; 102 ihold(inode); 103 req->r_num_caps = 1; 104 105 /* mds requires start and length rather than start and end */ 106 if (LLONG_MAX == fl->fl_end) 107 length = 0; 108 else 109 length = fl->fl_end - fl->fl_start + 1; 110 111 owner = secure_addr(fl->c.flc_owner); 112 113 doutc(cl, "rule: %d, op: %d, owner: %llx, pid: %llu, " 114 "start: %llu, length: %llu, wait: %d, type: %d\n", 115 (int)lock_type, (int)operation, owner, 116 (u64) fl->c.flc_pid, 117 fl->fl_start, length, wait, fl->c.flc_type); 118 119 req->r_args.filelock_change.rule = lock_type; 120 req->r_args.filelock_change.type = cmd; 121 req->r_args.filelock_change.owner = cpu_to_le64(owner); 122 req->r_args.filelock_change.pid = cpu_to_le64((u64) fl->c.flc_pid); 123 req->r_args.filelock_change.start = cpu_to_le64(fl->fl_start); 124 req->r_args.filelock_change.length = cpu_to_le64(length); 125 req->r_args.filelock_change.wait = wait; 126 127 err = ceph_mdsc_submit_request(mdsc, inode, req); 128 if (!err) 129 err = ceph_mdsc_wait_request(mdsc, req, wait ? 130 ceph_lock_wait_for_completion : NULL); 131 if (!err && operation == CEPH_MDS_OP_GETFILELOCK) { 132 fl->c.flc_pid = -le64_to_cpu(req->r_reply_info.filelock_reply->pid); 133 if (CEPH_LOCK_SHARED == req->r_reply_info.filelock_reply->type) 134 fl->c.flc_type = F_RDLCK; 135 else if (CEPH_LOCK_EXCL == req->r_reply_info.filelock_reply->type) 136 fl->c.flc_type = F_WRLCK; 137 else 138 fl->c.flc_type = F_UNLCK; 139 140 fl->fl_start = le64_to_cpu(req->r_reply_info.filelock_reply->start); 141 length = le64_to_cpu(req->r_reply_info.filelock_reply->start) + 142 le64_to_cpu(req->r_reply_info.filelock_reply->length); 143 if (length >= 1) 144 fl->fl_end = length -1; 145 else 146 fl->fl_end = 0; 147 148 } 149 ceph_mdsc_put_request(req); 150 doutc(cl, "rule: %d, op: %d, pid: %llu, start: %llu, " 151 "length: %llu, wait: %d, type: %d, err code %d\n", 152 (int)lock_type, (int)operation, (u64) fl->c.flc_pid, 153 fl->fl_start, length, wait, fl->c.flc_type, err); 154 return err; 155 } 156 157 static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc, 158 struct ceph_mds_request *req) 159 { 160 struct ceph_client *cl = mdsc->fsc->client; 161 struct ceph_mds_request *intr_req; 162 struct inode *inode = req->r_inode; 163 int err, lock_type; 164 165 BUG_ON(req->r_op != CEPH_MDS_OP_SETFILELOCK); 166 if (req->r_args.filelock_change.rule == CEPH_LOCK_FCNTL) 167 lock_type = CEPH_LOCK_FCNTL_INTR; 168 else if (req->r_args.filelock_change.rule == CEPH_LOCK_FLOCK) 169 lock_type = CEPH_LOCK_FLOCK_INTR; 170 else 171 BUG_ON(1); 172 BUG_ON(req->r_args.filelock_change.type == CEPH_LOCK_UNLOCK); 173 174 err = wait_for_completion_interruptible(&req->r_completion); 175 if (!err) 176 return 0; 177 178 doutc(cl, "request %llu was interrupted\n", req->r_tid); 179 180 mutex_lock(&mdsc->mutex); 181 if (test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags)) { 182 err = 0; 183 } else { 184 /* 185 * ensure we aren't running concurrently with 186 * ceph_fill_trace or ceph_readdir_prepopulate, which 187 * rely on locks (dir mutex) held by our caller. 188 */ 189 mutex_lock(&req->r_fill_mutex); 190 req->r_err = err; 191 set_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags); 192 mutex_unlock(&req->r_fill_mutex); 193 194 if (!req->r_session) { 195 // haven't sent the request 196 err = 0; 197 } 198 } 199 mutex_unlock(&mdsc->mutex); 200 if (!err) 201 return 0; 202 203 intr_req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SETFILELOCK, 204 USE_AUTH_MDS); 205 if (IS_ERR(intr_req)) 206 return PTR_ERR(intr_req); 207 208 intr_req->r_inode = inode; 209 ihold(inode); 210 intr_req->r_num_caps = 1; 211 212 intr_req->r_args.filelock_change = req->r_args.filelock_change; 213 intr_req->r_args.filelock_change.rule = lock_type; 214 intr_req->r_args.filelock_change.type = CEPH_LOCK_UNLOCK; 215 216 err = ceph_mdsc_do_request(mdsc, inode, intr_req); 217 ceph_mdsc_put_request(intr_req); 218 219 if (err && err != -ERESTARTSYS) 220 return err; 221 222 err = wait_for_completion_killable(&req->r_safe_completion); 223 if (err) 224 return err; 225 226 return 0; 227 } 228 229 static int try_unlock_file(struct file *file, struct file_lock *fl) 230 { 231 int err; 232 unsigned int orig_flags = fl->c.flc_flags; 233 fl->c.flc_flags |= FL_EXISTS; 234 err = locks_lock_file_wait(file, fl); 235 fl->c.flc_flags = orig_flags; 236 if (err == -ENOENT) { 237 if (!(orig_flags & FL_EXISTS)) 238 err = 0; 239 return err; 240 } 241 return 1; 242 } 243 244 /* 245 * Attempt to set an fcntl lock. 246 * For now, this just goes away to the server. Later it may be more awesome. 247 */ 248 int ceph_lock(struct file *file, int cmd, struct file_lock *fl) 249 { 250 struct inode *inode = file_inode(file); 251 struct ceph_inode_info *ci = ceph_inode(inode); 252 struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb); 253 struct ceph_client *cl = ceph_inode_to_client(inode); 254 int err = 0; 255 u16 op = CEPH_MDS_OP_SETFILELOCK; 256 u8 wait = 0; 257 u8 lock_cmd; 258 259 if (!(fl->c.flc_flags & FL_POSIX)) 260 return -ENOLCK; 261 262 if (ceph_inode_is_shutdown(inode)) 263 return -ESTALE; 264 265 doutc(cl, "fl_owner: %p\n", fl->c.flc_owner); 266 267 /* set wait bit as appropriate, then make command as Ceph expects it*/ 268 if (IS_GETLK(cmd)) 269 op = CEPH_MDS_OP_GETFILELOCK; 270 else if (IS_SETLKW(cmd)) 271 wait = 1; 272 273 if (test_bit(CEPH_I_ERROR_FILELOCK_BIT, &ci->i_ceph_flags)) { 274 if (op == CEPH_MDS_OP_SETFILELOCK && lock_is_unlock(fl)) 275 posix_lock_file(file, fl, NULL); 276 return -EIO; 277 } 278 279 /* Wait for reset to complete before acquiring new locks */ 280 if (op == CEPH_MDS_OP_SETFILELOCK && !lock_is_unlock(fl)) { 281 err = ceph_mdsc_wait_for_reset(mdsc); 282 if (err) 283 return err; 284 } 285 286 if (lock_is_read(fl)) 287 lock_cmd = CEPH_LOCK_SHARED; 288 else if (lock_is_write(fl)) 289 lock_cmd = CEPH_LOCK_EXCL; 290 else 291 lock_cmd = CEPH_LOCK_UNLOCK; 292 293 if (op == CEPH_MDS_OP_SETFILELOCK && lock_is_unlock(fl)) { 294 err = try_unlock_file(file, fl); 295 if (err <= 0) 296 return err; 297 } 298 299 err = ceph_lock_message(CEPH_LOCK_FCNTL, op, inode, lock_cmd, wait, fl); 300 if (!err) { 301 if (op == CEPH_MDS_OP_SETFILELOCK && F_UNLCK != fl->c.flc_type) { 302 doutc(cl, "locking locally\n"); 303 err = posix_lock_file(file, fl, NULL); 304 if (err) { 305 /* undo! This should only happen if 306 * the kernel detects local 307 * deadlock. */ 308 ceph_lock_message(CEPH_LOCK_FCNTL, op, inode, 309 CEPH_LOCK_UNLOCK, 0, fl); 310 doutc(cl, "got %d on posix_lock_file, undid lock\n", 311 err); 312 } 313 } 314 } 315 return err; 316 } 317 318 int ceph_flock(struct file *file, int cmd, struct file_lock *fl) 319 { 320 struct inode *inode = file_inode(file); 321 struct ceph_inode_info *ci = ceph_inode(inode); 322 struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb); 323 struct ceph_client *cl = ceph_inode_to_client(inode); 324 int err = 0; 325 u8 wait = 0; 326 u8 lock_cmd; 327 328 if (!(fl->c.flc_flags & FL_FLOCK)) 329 return -ENOLCK; 330 331 if (ceph_inode_is_shutdown(inode)) 332 return -ESTALE; 333 334 doutc(cl, "fl_file: %p\n", fl->c.flc_file); 335 336 if (test_bit(CEPH_I_ERROR_FILELOCK_BIT, &ci->i_ceph_flags)) { 337 if (lock_is_unlock(fl)) 338 locks_lock_file_wait(file, fl); 339 return -EIO; 340 } 341 342 /* Wait for reset to complete before acquiring new locks */ 343 if (!lock_is_unlock(fl)) { 344 err = ceph_mdsc_wait_for_reset(mdsc); 345 if (err) 346 return err; 347 } 348 349 if (IS_SETLKW(cmd)) 350 wait = 1; 351 352 if (lock_is_read(fl)) 353 lock_cmd = CEPH_LOCK_SHARED; 354 else if (lock_is_write(fl)) 355 lock_cmd = CEPH_LOCK_EXCL; 356 else 357 lock_cmd = CEPH_LOCK_UNLOCK; 358 359 if (lock_is_unlock(fl)) { 360 err = try_unlock_file(file, fl); 361 if (err <= 0) 362 return err; 363 } 364 365 err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK, 366 inode, lock_cmd, wait, fl); 367 if (!err && F_UNLCK != fl->c.flc_type) { 368 err = locks_lock_file_wait(file, fl); 369 if (err) { 370 ceph_lock_message(CEPH_LOCK_FLOCK, 371 CEPH_MDS_OP_SETFILELOCK, 372 inode, CEPH_LOCK_UNLOCK, 0, fl); 373 doutc(cl, "got %d on locks_lock_file_wait, undid lock\n", 374 err); 375 } 376 } 377 return err; 378 } 379 380 /* 381 * Fills in the passed counter variables, so you can prepare pagelist metadata 382 * before calling ceph_encode_locks. 383 */ 384 void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count) 385 { 386 struct ceph_client *cl = ceph_inode_to_client(inode); 387 struct file_lock *lock; 388 struct file_lock_context *ctx; 389 390 *fcntl_count = 0; 391 *flock_count = 0; 392 393 ctx = locks_inode_context(inode); 394 if (ctx) { 395 spin_lock(&ctx->flc_lock); 396 for_each_file_lock(lock, &ctx->flc_posix) 397 ++(*fcntl_count); 398 for_each_file_lock(lock, &ctx->flc_flock) 399 ++(*flock_count); 400 spin_unlock(&ctx->flc_lock); 401 } 402 doutc(cl, "counted %d flock locks and %d fcntl locks\n", 403 *flock_count, *fcntl_count); 404 } 405 406 /* 407 * Given a pointer to a lock, convert it to a ceph filelock 408 */ 409 static int lock_to_ceph_filelock(struct inode *inode, 410 struct file_lock *lock, 411 struct ceph_filelock *cephlock) 412 { 413 struct ceph_client *cl = ceph_inode_to_client(inode); 414 int err = 0; 415 416 cephlock->start = cpu_to_le64(lock->fl_start); 417 cephlock->length = cpu_to_le64(lock->fl_end - lock->fl_start + 1); 418 cephlock->client = cpu_to_le64(0); 419 cephlock->pid = cpu_to_le64((u64) lock->c.flc_pid); 420 cephlock->owner = cpu_to_le64(secure_addr(lock->c.flc_owner)); 421 422 switch (lock->c.flc_type) { 423 case F_RDLCK: 424 cephlock->type = CEPH_LOCK_SHARED; 425 break; 426 case F_WRLCK: 427 cephlock->type = CEPH_LOCK_EXCL; 428 break; 429 case F_UNLCK: 430 cephlock->type = CEPH_LOCK_UNLOCK; 431 break; 432 default: 433 doutc(cl, "Have unknown lock type %d\n", 434 lock->c.flc_type); 435 err = -EINVAL; 436 } 437 438 return err; 439 } 440 441 /* 442 * Encode the flock and fcntl locks for the given inode into the ceph_filelock 443 * array. Must be called with inode->i_lock already held. 444 * If we encounter more of a specific lock type than expected, return -ENOSPC. 445 */ 446 int ceph_encode_locks_to_buffer(struct inode *inode, 447 struct ceph_filelock *flocks, 448 int num_fcntl_locks, int num_flock_locks) 449 { 450 struct file_lock *lock; 451 struct file_lock_context *ctx = locks_inode_context(inode); 452 struct ceph_client *cl = ceph_inode_to_client(inode); 453 int err = 0; 454 int seen_fcntl = 0; 455 int seen_flock = 0; 456 int l = 0; 457 458 doutc(cl, "encoding %d flock and %d fcntl locks\n", num_flock_locks, 459 num_fcntl_locks); 460 461 if (!ctx) 462 return 0; 463 464 spin_lock(&ctx->flc_lock); 465 for_each_file_lock(lock, &ctx->flc_posix) { 466 ++seen_fcntl; 467 if (seen_fcntl > num_fcntl_locks) { 468 err = -ENOSPC; 469 goto fail; 470 } 471 err = lock_to_ceph_filelock(inode, lock, &flocks[l]); 472 if (err) 473 goto fail; 474 ++l; 475 } 476 for_each_file_lock(lock, &ctx->flc_flock) { 477 ++seen_flock; 478 if (seen_flock > num_flock_locks) { 479 err = -ENOSPC; 480 goto fail; 481 } 482 err = lock_to_ceph_filelock(inode, lock, &flocks[l]); 483 if (err) 484 goto fail; 485 ++l; 486 } 487 fail: 488 spin_unlock(&ctx->flc_lock); 489 return err; 490 } 491 492 /* 493 * Copy the encoded flock and fcntl locks into the pagelist. 494 * Format is: #fcntl locks, sequential fcntl locks, #flock locks, 495 * sequential flock locks. 496 * Returns zero on success. 497 */ 498 int ceph_locks_to_pagelist(struct ceph_filelock *flocks, 499 struct ceph_pagelist *pagelist, 500 int num_fcntl_locks, int num_flock_locks) 501 { 502 int err = 0; 503 __le32 nlocks; 504 505 nlocks = cpu_to_le32(num_fcntl_locks); 506 err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks)); 507 if (err) 508 goto out_fail; 509 510 if (num_fcntl_locks > 0) { 511 err = ceph_pagelist_append(pagelist, flocks, 512 num_fcntl_locks * sizeof(*flocks)); 513 if (err) 514 goto out_fail; 515 } 516 517 nlocks = cpu_to_le32(num_flock_locks); 518 err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks)); 519 if (err) 520 goto out_fail; 521 522 if (num_flock_locks > 0) { 523 err = ceph_pagelist_append(pagelist, &flocks[num_fcntl_locks], 524 num_flock_locks * sizeof(*flocks)); 525 } 526 out_fail: 527 return err; 528 } 529