| 1 | |
| 2 | |
| 3 | * linux/fs/locks.c
|
| 4 | *
|
| 5 | * We implement four types of file locks: BSD locks, posix locks, open
|
| 6 | * file description locks, and leases. For details about BSD locks,
|
| 7 | * see the flock(2) man page; for details about the other three, see
|
| 8 | * fcntl(2).
|
| 9 | *
|
| 10 | *
|
| 11 | * Locking conflicts and dependencies:
|
| 12 | * If multiple threads attempt to lock the same byte (or flock the same file)
|
| 13 | * only one can be granted the lock, and other must wait their turn.
|
| 14 | * The first lock has been "applied" or "granted", the others are "waiting"
|
| 15 | * and are "blocked" by the "applied" lock..
|
| 16 | *
|
| 17 | * Waiting and applied locks are all kept in trees whose properties are:
|
| 18 | *
|
| 19 | * - the root of a tree may be an applied or waiting lock.
|
| 20 | * - every other node in the tree is a waiting lock that
|
| 21 | * conflicts with every ancestor of that node.
|
| 22 | *
|
| 23 | * Every such tree begins life as a waiting singleton which obviously
|
| 24 | * satisfies the above properties.
|
| 25 | *
|
| 26 | * The only ways we modify trees preserve these properties:
|
| 27 | *
|
| 28 | * 1. We may add a new leaf node, but only after first verifying that it
|
| 29 | * conflicts with all of its ancestors.
|
| 30 | * 2. We may remove the root of a tree, creating a new singleton
|
| 31 | * tree from the root and N new trees rooted in the immediate
|
| 32 | * children.
|
| 33 | * 3. If the root of a tree is not currently an applied lock, we may
|
| 34 | * apply it (if possible).
|
| 35 | * 4. We may upgrade the root of the tree (either extend its range,
|
| 36 | * or upgrade its entire range from read to write).
|
| 37 | *
|
| 38 | * When an applied lock is modified in a way that reduces or downgrades any
|
| 39 | * part of its range, we remove all its children (2 above). This particularly
|
| 40 | * happens when a lock is unlocked.
|
| 41 | *
|
| 42 | * For each of those child trees we "wake up" the thread which is
|
| 43 | * waiting for the lock so it can continue handling as follows: if the
|
| 44 | * root of the tree applies, we do so (3). If it doesn't, it must
|
| 45 | * conflict with some applied lock. We remove (wake up) all of its children
|
| 46 | * (2), and add it is a new leaf to the tree rooted in the applied
|
| 47 | * lock (1). We then repeat the process recursively with those
|
| 48 | * children.
|
| 49 | *
|
| 50 |
|
| 51 | #include <linux/capability.h>
|
| 52 | #include <linux/file.h>
|
| 53 | #include <linux/fdtable.h>
|
| 54 | #include <linux/filelock.h>
|
| 55 | #include <linux/fs.h>
|
| 56 | #include <linux/init.h>
|
| 57 | #include <linux/security.h>
|
| 58 | #include <linux/slab.h>
|
| 59 | #include <linux/syscalls.h>
|
| 60 | #include <linux/time.h>
|
| 61 | #include <linux/rcupdate.h>
|
| 62 | #include <linux/pid_namespace.h>
|
| 63 | #include <linux/hashtable.h>
|
| 64 | #include <linux/percpu.h>
|
| 65 | #include <linux/sysctl.h>
|
| 66 |
|
| 67 | #define CREATE_TRACE_POINTS
|
| 68 | #include <trace/events/filelock.h>
|
| 69 |
|
| 70 | #include <linux/uaccess.h>
|
| 71 |
|
| 72 | static struct file_lock *file_lock(struct file_lock_core *flc)
|
| 73 | {
|
| 74 | return container_of(flc, struct file_lock, c);
|
| 75 | }
|
| 76 |
|
| 77 | static struct file_lease *file_lease(struct file_lock_core *flc)
|
| 78 | {
|
| 79 | return container_of(flc, struct file_lease, c);
|
| 80 | }
|
| 81 |
|
| 82 | static bool lease_breaking(struct file_lease *fl)
|
| 83 | {
|
| 84 | return fl->c.flc_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING);
|
| 85 | }
|
| 86 |
|
| 87 | static int target_leasetype(struct file_lease *fl)
|
| 88 | {
|
| 89 | if (fl->c.flc_flags & FL_UNLOCK_PENDING)
|
| 90 | return F_UNLCK;
|
| 91 | if (fl->c.flc_flags & FL_DOWNGRADE_PENDING)
|
| 92 | return F_RDLCK;
|
| 93 | return fl->c.flc_type;
|
| 94 | }
|
| 95 |
|
| 96 | static int leases_enable = 1;
|
| 97 | static int lease_break_time = 45;
|
| 98 |
|
| 99 | #ifdef CONFIG_SYSCTL
|
| 100 | static const struct ctl_table locks_sysctls[] = {
|
| 101 | {
|
| 102 | .procname = "leases-enable",
|
| 103 | .data = &leases_enable,
|
| 104 | .maxlen = sizeof(int),
|
| 105 | .mode = 0644,
|
| 106 | .proc_handler = proc_dointvec,
|
| 107 | },
|
| 108 | #ifdef CONFIG_MMU
|
| 109 | {
|
| 110 | .procname = "lease-break-time",
|
| 111 | .data = &lease_break_time,
|
| 112 | .maxlen = sizeof(int),
|
| 113 | .mode = 0644,
|
| 114 | .proc_handler = proc_dointvec,
|
| 115 | },
|
| 116 | #endif
|
| 117 | };
|
| 118 |
|
| 119 | static int __init init_fs_locks_sysctls(void)
|
| 120 | {
|
| 121 | register_sysctl_init("fs", locks_sysctls);
|
| 122 | return 0;
|
| 123 | }
|
| 124 | early_initcall(init_fs_locks_sysctls);
|
| 125 | #endif
|
| 126 |
|
| 127 | |
| 128 | * The global file_lock_list is only used for displaying /proc/locks, so we
|
| 129 | * keep a list on each CPU, with each list protected by its own spinlock.
|
| 130 | * Global serialization is done using file_rwsem.
|
| 131 | *
|
| 132 | * Note that alterations to the list also require that the relevant flc_lock is
|
| 133 | * held.
|
| 134 |
|
| 135 | struct file_lock_list_struct {
|
| 136 | spinlock_t lock;
|
| 137 | struct hlist_head hlist;
|
| 138 | };
|
| 139 | static DEFINE_PER_CPU(struct file_lock_list_struct, file_lock_list);
|
| 140 | DEFINE_STATIC_PERCPU_RWSEM(file_rwsem);
|
| 141 |
|
| 142 |
|
| 143 | |
| 144 | * The blocked_hash is used to find POSIX lock loops for deadlock detection.
|
| 145 | * It is protected by blocked_lock_lock.
|
| 146 | *
|
| 147 | * We hash locks by lockowner in order to optimize searching for the lock a
|
| 148 | * particular lockowner is waiting on.
|
| 149 | *
|
| 150 | * FIXME: make this value scale via some heuristic? We generally will want more
|
| 151 | * buckets when we have more lockowners holding locks, but that's a little
|
| 152 | * difficult to determine without knowing what the workload will look like.
|
| 153 |
|
| 154 | #define BLOCKED_HASH_BITS 7
|
| 155 | static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS);
|
| 156 |
|
| 157 | |
| 158 | * This lock protects the blocked_hash. Generally, if you're accessing it, you
|
| 159 | * want to be holding this lock.
|
| 160 | *
|
| 161 | * In addition, it also protects the fl->fl_blocked_requests list, and the
|
| 162 | * fl->fl_blocker pointer for file_lock structures that are acting as lock
|
| 163 | * requests (in contrast to those that are acting as records of acquired locks).
|
| 164 | *
|
| 165 | * Note that when we acquire this lock in order to change the above fields,
|
| 166 | * we often hold the flc_lock as well. In certain cases, when reading the fields
|
| 167 | * protected by this lock, we can skip acquiring it iff we already hold the
|
| 168 | * flc_lock.
|
| 169 |
|
| 170 | static DEFINE_SPINLOCK(blocked_lock_lock);
|
| 171 |
|
| 172 | static struct kmem_cache *flctx_cache __ro_after_init;
|
| 173 | static struct kmem_cache *filelock_cache __ro_after_init;
|
| 174 | static struct kmem_cache *filelease_cache __ro_after_init;
|
| 175 |
|
| 176 | static struct file_lock_context *
|
| 177 | locks_get_lock_context(struct inode *inode, int type)
|
| 178 | {
|
| 179 | struct file_lock_context *ctx;
|
| 180 |
|
| 181 | ctx = locks_inode_context(inode);
|
| 182 | if (likely(ctx) || type == F_UNLCK)
|
| 183 | goto out;
|
| 184 |
|
| 185 | ctx = kmem_cache_alloc(flctx_cache, GFP_KERNEL);
|
| 186 | if (!ctx)
|
| 187 | goto out;
|
| 188 |
|
| 189 | spin_lock_init(&ctx->flc_lock);
|
| 190 | INIT_LIST_HEAD(&ctx->flc_flock);
|
| 191 | INIT_LIST_HEAD(&ctx->flc_posix);
|
| 192 | INIT_LIST_HEAD(&ctx->flc_lease);
|
| 193 |
|
| 194 | |
| 195 | * Assign the pointer if it's not already assigned. If it is, then
|
| 196 | * free the context we just allocated.
|
| 197 |
|
| 198 | spin_lock(&inode->i_lock);
|
| 199 | if (!(inode->i_opflags & IOP_FLCTX)) {
|
| 200 | VFS_BUG_ON_INODE(inode->i_flctx, inode);
|
| 201 | WRITE_ONCE(inode->i_flctx, ctx);
|
| 202 | |
| 203 | * Paired with locks_inode_context().
|
| 204 |
|
| 205 | smp_store_release(&inode->i_opflags, inode->i_opflags | IOP_FLCTX);
|
| 206 | spin_unlock(&inode->i_lock);
|
| 207 | } else {
|
| 208 | VFS_BUG_ON_INODE(!inode->i_flctx, inode);
|
| 209 | spin_unlock(&inode->i_lock);
|
| 210 | kmem_cache_free(flctx_cache, ctx);
|
| 211 | ctx = locks_inode_context(inode);
|
| 212 | }
|
| 213 | out:
|
| 214 | trace_locks_get_lock_context(inode, type, ctx);
|
| 215 | return ctx;
|
| 216 | }
|
| 217 |
|
| 218 | static void
|
| 219 | locks_dump_ctx_list(struct list_head *list, char *list_type)
|
| 220 | {
|
| 221 | struct file_lock_core *flc;
|
| 222 |
|
| 223 | list_for_each_entry(flc, list, flc_list)
|
| 224 | pr_warn("%s: fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n",
|
| 225 | list_type, flc->flc_owner, flc->flc_flags,
|
| 226 | flc->flc_type, flc->flc_pid);
|
| 227 | }
|
| 228 |
|
| 229 | static void
|
| 230 | locks_check_ctx_lists(struct inode *inode)
|
| 231 | {
|
| 232 | struct file_lock_context *ctx = inode->i_flctx;
|
| 233 |
|
| 234 | if (unlikely(!list_empty(&ctx->flc_flock) ||
|
| 235 | !list_empty(&ctx->flc_posix) ||
|
| 236 | !list_empty(&ctx->flc_lease))) {
|
| 237 | pr_warn("Leaked locks on dev=0x%x:0x%x ino=0x%llx:\n",
|
| 238 | MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev),
|
| 239 | inode->i_ino);
|
| 240 | locks_dump_ctx_list(&ctx->flc_flock, "FLOCK");
|
| 241 | locks_dump_ctx_list(&ctx->flc_posix, "POSIX");
|
| 242 | locks_dump_ctx_list(&ctx->flc_lease, "LEASE");
|
| 243 | }
|
| 244 | }
|
| 245 |
|
| 246 | static void
|
| 247 | locks_check_ctx_file_list(struct file *filp, struct list_head *list, char *list_type)
|
| 248 | {
|
| 249 | struct file_lock_core *flc;
|
| 250 | struct inode *inode = file_inode(filp);
|
| 251 |
|
| 252 | list_for_each_entry(flc, list, flc_list)
|
| 253 | if (flc->flc_file == filp)
|
| 254 | pr_warn("Leaked %s lock on dev=0x%x:0x%x ino=0x%llx "
|
| 255 | " fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n",
|
| 256 | list_type, MAJOR(inode->i_sb->s_dev),
|
| 257 | MINOR(inode->i_sb->s_dev), inode->i_ino,
|
| 258 | flc->flc_owner, flc->flc_flags,
|
| 259 | flc->flc_type, flc->flc_pid);
|
| 260 | }
|
| 261 |
|
| 262 | void
|
| 263 | locks_free_lock_context(struct inode *inode)
|
| 264 | {
|
| 265 | struct file_lock_context *ctx = locks_inode_context(inode);
|
| 266 |
|
| 267 | if (unlikely(ctx)) {
|
| 268 | locks_check_ctx_lists(inode);
|
| 269 | kmem_cache_free(flctx_cache, ctx);
|
| 270 | }
|
| 271 | }
|
| 272 |
|
| 273 | static void locks_init_lock_heads(struct file_lock_core *flc)
|
| 274 | {
|
| 275 | INIT_HLIST_NODE(&flc->flc_link);
|
| 276 | INIT_LIST_HEAD(&flc->flc_list);
|
| 277 | INIT_LIST_HEAD(&flc->flc_blocked_requests);
|
| 278 | INIT_LIST_HEAD(&flc->flc_blocked_member);
|
| 279 | init_waitqueue_head(&flc->flc_wait);
|
| 280 | }
|
| 281 |
|
| 282 |
|
| 283 | struct file_lock *locks_alloc_lock(void)
|
| 284 | {
|
| 285 | struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL);
|
| 286 |
|
| 287 | if (fl)
|
| 288 | locks_init_lock_heads(&fl->c);
|
| 289 |
|
| 290 | return fl;
|
| 291 | }
|
| 292 | EXPORT_SYMBOL_GPL(locks_alloc_lock);
|
| 293 |
|
| 294 |
|
| 295 | struct file_lease *locks_alloc_lease(void)
|
| 296 | {
|
| 297 | struct file_lease *fl = kmem_cache_zalloc(filelease_cache, GFP_KERNEL);
|
| 298 |
|
| 299 | if (fl)
|
| 300 | locks_init_lock_heads(&fl->c);
|
| 301 |
|
| 302 | return fl;
|
| 303 | }
|
| 304 | EXPORT_SYMBOL_GPL(locks_alloc_lease);
|
| 305 |
|
| 306 | void locks_release_private(struct file_lock *fl)
|
| 307 | {
|
| 308 | struct file_lock_core *flc = &fl->c;
|
| 309 |
|
| 310 | BUG_ON(waitqueue_active(&flc->flc_wait));
|
| 311 | BUG_ON(!list_empty(&flc->flc_list));
|
| 312 | BUG_ON(!list_empty(&flc->flc_blocked_requests));
|
| 313 | BUG_ON(!list_empty(&flc->flc_blocked_member));
|
| 314 | BUG_ON(!hlist_unhashed(&flc->flc_link));
|
| 315 |
|
| 316 | if (fl->fl_ops) {
|
| 317 | if (fl->fl_ops->fl_release_private)
|
| 318 | fl->fl_ops->fl_release_private(fl);
|
| 319 | fl->fl_ops = NULL;
|
| 320 | }
|
| 321 |
|
| 322 | if (fl->fl_lmops) {
|
| 323 | if (fl->fl_lmops->lm_put_owner) {
|
| 324 | fl->fl_lmops->lm_put_owner(flc->flc_owner);
|
| 325 | flc->flc_owner = NULL;
|
| 326 | }
|
| 327 | fl->fl_lmops = NULL;
|
| 328 | }
|
| 329 | }
|
| 330 | EXPORT_SYMBOL_GPL(locks_release_private);
|
| 331 |
|
| 332 | |
| 333 | * locks_owner_has_blockers - Check for blocking lock requests
|
| 334 | * @flctx: file lock context
|
| 335 | * @owner: lock owner
|
| 336 | *
|
| 337 | * Return values:
|
| 338 | * %true: @owner has at least one blocker
|
| 339 | * %false: @owner has no blockers
|
| 340 |
|
| 341 | bool locks_owner_has_blockers(struct file_lock_context *flctx, fl_owner_t owner)
|
| 342 | {
|
| 343 | struct file_lock_core *flc;
|
| 344 |
|
| 345 | spin_lock(&flctx->flc_lock);
|
| 346 | list_for_each_entry(flc, &flctx->flc_posix, flc_list) {
|
| 347 | if (flc->flc_owner != owner)
|
| 348 | continue;
|
| 349 | if (!list_empty(&flc->flc_blocked_requests)) {
|
| 350 | spin_unlock(&flctx->flc_lock);
|
| 351 | return true;
|
| 352 | }
|
| 353 | }
|
| 354 | spin_unlock(&flctx->flc_lock);
|
| 355 | return false;
|
| 356 | }
|
| 357 | EXPORT_SYMBOL_GPL(locks_owner_has_blockers);
|
| 358 |
|
| 359 |
|
| 360 | void locks_free_lock(struct file_lock *fl)
|
| 361 | {
|
| 362 | locks_release_private(fl);
|
| 363 | kmem_cache_free(filelock_cache, fl);
|
| 364 | }
|
| 365 | EXPORT_SYMBOL(locks_free_lock);
|
| 366 |
|
| 367 |
|
| 368 | void locks_free_lease(struct file_lease *fl)
|
| 369 | {
|
| 370 | kmem_cache_free(filelease_cache, fl);
|
| 371 | }
|
| 372 | EXPORT_SYMBOL(locks_free_lease);
|
| 373 |
|
| 374 | static void
|
| 375 | locks_dispose_list(struct list_head *dispose)
|
| 376 | {
|
| 377 | struct file_lock_core *flc;
|
| 378 |
|
| 379 | while (!list_empty(dispose)) {
|
| 380 | flc = list_first_entry(dispose, struct file_lock_core, flc_list);
|
| 381 | list_del_init(&flc->flc_list);
|
| 382 | locks_free_lock(file_lock(flc));
|
| 383 | }
|
| 384 | }
|
| 385 |
|
| 386 | static void
|
| 387 | lease_dispose_list(struct list_head *dispose)
|
| 388 | {
|
| 389 | struct file_lock_core *flc;
|
| 390 |
|
| 391 | while (!list_empty(dispose)) {
|
| 392 | flc = list_first_entry(dispose, struct file_lock_core, flc_list);
|
| 393 | list_del_init(&flc->flc_list);
|
| 394 | locks_free_lease(file_lease(flc));
|
| 395 | }
|
| 396 | }
|
| 397 |
|
| 398 | void locks_init_lock(struct file_lock *fl)
|
| 399 | {
|
| 400 | memset(fl, 0, sizeof(struct file_lock));
|
| 401 | locks_init_lock_heads(&fl->c);
|
| 402 | }
|
| 403 | EXPORT_SYMBOL(locks_init_lock);
|
| 404 |
|
| 405 | void locks_init_lease(struct file_lease *fl)
|
| 406 | {
|
| 407 | memset(fl, 0, sizeof(*fl));
|
| 408 | locks_init_lock_heads(&fl->c);
|
| 409 | }
|
| 410 | EXPORT_SYMBOL(locks_init_lease);
|
| 411 |
|
| 412 | |
| 413 | * Initialize a new lock from an existing file_lock structure.
|
| 414 |
|
| 415 | void locks_copy_conflock(struct file_lock *new, struct file_lock *fl)
|
| 416 | {
|
| 417 | new->c.flc_owner = fl->c.flc_owner;
|
| 418 | new->c.flc_pid = fl->c.flc_pid;
|
| 419 | new->c.flc_file = NULL;
|
| 420 | new->c.flc_flags = fl->c.flc_flags;
|
| 421 | new->c.flc_type = fl->c.flc_type;
|
| 422 | new->fl_start = fl->fl_start;
|
| 423 | new->fl_end = fl->fl_end;
|
| 424 | new->fl_lmops = fl->fl_lmops;
|
| 425 | new->fl_ops = NULL;
|
| 426 |
|
| 427 | if (fl->fl_lmops) {
|
| 428 | if (fl->fl_lmops->lm_get_owner)
|
| 429 | fl->fl_lmops->lm_get_owner(fl->c.flc_owner);
|
| 430 | }
|
| 431 | }
|
| 432 | EXPORT_SYMBOL(locks_copy_conflock);
|
| 433 |
|
| 434 | void locks_copy_lock(struct file_lock *new, struct file_lock *fl)
|
| 435 | {
|
| 436 |
|
| 437 | WARN_ON_ONCE(new->fl_ops);
|
| 438 |
|
| 439 | locks_copy_conflock(new, fl);
|
| 440 |
|
| 441 | new->c.flc_file = fl->c.flc_file;
|
| 442 | new->fl_ops = fl->fl_ops;
|
| 443 |
|
| 444 | if (fl->fl_ops) {
|
| 445 | if (fl->fl_ops->fl_copy_lock)
|
| 446 | fl->fl_ops->fl_copy_lock(new, fl);
|
| 447 | }
|
| 448 | }
|
| 449 | EXPORT_SYMBOL(locks_copy_lock);
|
| 450 |
|
| 451 | static void locks_move_blocks(struct file_lock *new, struct file_lock *fl)
|
| 452 | {
|
| 453 | struct file_lock *f;
|
| 454 |
|
| 455 | |
| 456 | * As ctx->flc_lock is held, new requests cannot be added to
|
| 457 | * ->flc_blocked_requests, so we don't need a lock to check if it
|
| 458 | * is empty.
|
| 459 |
|
| 460 | if (list_empty(&fl->c.flc_blocked_requests))
|
| 461 | return;
|
| 462 | spin_lock(&blocked_lock_lock);
|
| 463 | list_splice_init(&fl->c.flc_blocked_requests,
|
| 464 | &new->c.flc_blocked_requests);
|
| 465 | list_for_each_entry(f, &new->c.flc_blocked_requests,
|
| 466 | c.flc_blocked_member)
|
| 467 | f->c.flc_blocker = &new->c;
|
| 468 | spin_unlock(&blocked_lock_lock);
|
| 469 | }
|
| 470 |
|
| 471 | static inline int flock_translate_cmd(int cmd) {
|
| 472 | switch (cmd) {
|
| 473 | case LOCK_SH:
|
| 474 | return F_RDLCK;
|
| 475 | case LOCK_EX:
|
| 476 | return F_WRLCK;
|
| 477 | case LOCK_UN:
|
| 478 | return F_UNLCK;
|
| 479 | }
|
| 480 | return -EINVAL;
|
| 481 | }
|
| 482 |
|
| 483 |
|
| 484 | static void flock_make_lock(struct file *filp, struct file_lock *fl, int type)
|
| 485 | {
|
| 486 | locks_init_lock(fl);
|
| 487 |
|
| 488 | fl->c.flc_file = filp;
|
| 489 | fl->c.flc_owner = filp;
|
| 490 | fl->c.flc_pid = current->tgid;
|
| 491 | fl->c.flc_flags = FL_FLOCK;
|
| 492 | fl->c.flc_type = type;
|
| 493 | fl->fl_end = OFFSET_MAX;
|
| 494 | }
|
| 495 |
|
| 496 | static int assign_type(struct file_lock_core *flc, int type)
|
| 497 | {
|
| 498 | switch (type) {
|
| 499 | case F_RDLCK:
|
| 500 | case F_WRLCK:
|
| 501 | case F_UNLCK:
|
| 502 | flc->flc_type = type;
|
| 503 | break;
|
| 504 | default:
|
| 505 | return -EINVAL;
|
| 506 | }
|
| 507 | return 0;
|
| 508 | }
|
| 509 |
|
| 510 | static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
|
| 511 | struct flock64 *l)
|
| 512 | {
|
| 513 | switch (l->l_whence) {
|
| 514 | case SEEK_SET:
|
| 515 | fl->fl_start = 0;
|
| 516 | break;
|
| 517 | case SEEK_CUR:
|
| 518 | fl->fl_start = filp->f_pos;
|
| 519 | break;
|
| 520 | case SEEK_END:
|
| 521 | fl->fl_start = i_size_read(file_inode(filp));
|
| 522 | break;
|
| 523 | default:
|
| 524 | return -EINVAL;
|
| 525 | }
|
| 526 | if (l->l_start > OFFSET_MAX - fl->fl_start)
|
| 527 | return -EOVERFLOW;
|
| 528 | fl->fl_start += l->l_start;
|
| 529 | if (fl->fl_start < 0)
|
| 530 | return -EINVAL;
|
| 531 |
|
| 532 | |
| 533 | POSIX-2001 defines it.
|
| 534 | if (l->l_len > 0) {
|
| 535 | if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
|
| 536 | return -EOVERFLOW;
|
| 537 | fl->fl_end = fl->fl_start + (l->l_len - 1);
|
| 538 |
|
| 539 | } else if (l->l_len < 0) {
|
| 540 | if (fl->fl_start + l->l_len < 0)
|
| 541 | return -EINVAL;
|
| 542 | fl->fl_end = fl->fl_start - 1;
|
| 543 | fl->fl_start += l->l_len;
|
| 544 | } else
|
| 545 | fl->fl_end = OFFSET_MAX;
|
| 546 |
|
| 547 | fl->c.flc_owner = current->files;
|
| 548 | fl->c.flc_pid = current->tgid;
|
| 549 | fl->c.flc_file = filp;
|
| 550 | fl->c.flc_flags = FL_POSIX;
|
| 551 | fl->fl_ops = NULL;
|
| 552 | fl->fl_lmops = NULL;
|
| 553 |
|
| 554 | return assign_type(&fl->c, l->l_type);
|
| 555 | }
|
| 556 |
|
| 557 | |
| 558 | * style lock.
|
| 559 |
|
| 560 | static int flock_to_posix_lock(struct file *filp, struct file_lock *fl,
|
| 561 | struct flock *l)
|
| 562 | {
|
| 563 | struct flock64 ll = {
|
| 564 | .l_type = l->l_type,
|
| 565 | .l_whence = l->l_whence,
|
| 566 | .l_start = l->l_start,
|
| 567 | .l_len = l->l_len,
|
| 568 | };
|
| 569 |
|
| 570 | return flock64_to_posix_lock(filp, fl, &ll);
|
| 571 | }
|
| 572 |
|
| 573 |
|
| 574 | static bool
|
| 575 | lease_break_callback(struct file_lease *fl)
|
| 576 | {
|
| 577 | kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG);
|
| 578 | return false;
|
| 579 | }
|
| 580 |
|
| 581 | static void
|
| 582 | lease_setup(struct file_lease *fl, void **priv)
|
| 583 | {
|
| 584 | struct file *filp = fl->c.flc_file;
|
| 585 | struct fasync_struct *fa = *priv;
|
| 586 |
|
| 587 | |
| 588 | * fasync_insert_entry() returns the old entry if any. If there was no
|
| 589 | * old entry, then it used "priv" and inserted it into the fasync list.
|
| 590 | * Clear the pointer to indicate that it shouldn't be freed.
|
| 591 |
|
| 592 | if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa))
|
| 593 | *priv = NULL;
|
| 594 |
|
| 595 | __f_setown(filp, task_pid(current), PIDTYPE_TGID, 0);
|
| 596 | }
|
| 597 |
|
| 598 | |
| 599 | * lease_open_conflict - see if the given file points to an inode that has
|
| 600 | * an existing open that would conflict with the
|
| 601 | * desired lease.
|
| 602 | * @filp: file to check
|
| 603 | * @arg: type of lease that we're trying to acquire
|
| 604 | *
|
| 605 | * Check to see if there's an existing open fd on this file that would
|
| 606 | * conflict with the lease we're trying to set.
|
| 607 |
|
| 608 | static int
|
| 609 | lease_open_conflict(struct file *filp, const int arg)
|
| 610 | {
|
| 611 | struct inode *inode = file_inode(filp);
|
| 612 | int self_wcount = 0, self_rcount = 0;
|
| 613 |
|
| 614 | if (arg == F_RDLCK)
|
| 615 | return inode_is_open_for_write(inode) ? -EAGAIN : 0;
|
| 616 | else if (arg != F_WRLCK)
|
| 617 | return 0;
|
| 618 |
|
| 619 | |
| 620 | * Make sure that only read/write count is from lease requestor.
|
| 621 | * Note that this will result in denying write leases when i_writecount
|
| 622 | * is negative, which is what we want. (We shouldn't grant write leases
|
| 623 | * on files open for execution.)
|
| 624 |
|
| 625 | if (filp->f_mode & FMODE_WRITE)
|
| 626 | self_wcount = 1;
|
| 627 | else if (filp->f_mode & FMODE_READ)
|
| 628 | self_rcount = 1;
|
| 629 |
|
| 630 | if (atomic_read(&inode->i_writecount) != self_wcount ||
|
| 631 | atomic_read(&inode->i_readcount) != self_rcount)
|
| 632 | return -EAGAIN;
|
| 633 |
|
| 634 | return 0;
|
| 635 | }
|
| 636 |
|
| 637 | static const struct lease_manager_operations lease_manager_ops = {
|
| 638 | .lm_break = lease_break_callback,
|
| 639 | .lm_change = lease_modify,
|
| 640 | .lm_setup = lease_setup,
|
| 641 | .lm_open_conflict = lease_open_conflict,
|
| 642 | };
|
| 643 |
|
| 644 | |
| 645 | * Initialize a lease, use the default lock manager operations
|
| 646 |
|
| 647 | static int lease_init(struct file *filp, unsigned int flags, int type, struct file_lease *fl)
|
| 648 | {
|
| 649 | if (assign_type(&fl->c, type) != 0)
|
| 650 | return -EINVAL;
|
| 651 |
|
| 652 | fl->c.flc_owner = filp;
|
| 653 | fl->c.flc_pid = current->tgid;
|
| 654 |
|
| 655 | fl->c.flc_file = filp;
|
| 656 | fl->c.flc_flags = flags;
|
| 657 | fl->fl_lmops = &lease_manager_ops;
|
| 658 | return 0;
|
| 659 | }
|
| 660 |
|
| 661 |
|
| 662 | static struct file_lease *lease_alloc(struct file *filp, unsigned int flags, int type)
|
| 663 | {
|
| 664 | struct file_lease *fl = locks_alloc_lease();
|
| 665 | int error = -ENOMEM;
|
| 666 |
|
| 667 | if (fl == NULL)
|
| 668 | return ERR_PTR(error);
|
| 669 |
|
| 670 | error = lease_init(filp, flags, type, fl);
|
| 671 | if (error) {
|
| 672 | locks_free_lease(fl);
|
| 673 | return ERR_PTR(error);
|
| 674 | }
|
| 675 | return fl;
|
| 676 | }
|
| 677 |
|
| 678 | |
| 679 |
|
| 680 | static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2)
|
| 681 | {
|
| 682 | return ((fl1->fl_end >= fl2->fl_start) &&
|
| 683 | (fl2->fl_end >= fl1->fl_start));
|
| 684 | }
|
| 685 |
|
| 686 | |
| 687 | * Check whether two locks have the same owner.
|
| 688 |
|
| 689 | static int posix_same_owner(struct file_lock_core *fl1, struct file_lock_core *fl2)
|
| 690 | {
|
| 691 | return fl1->flc_owner == fl2->flc_owner;
|
| 692 | }
|
| 693 |
|
| 694 |
|
| 695 | static void locks_insert_global_locks(struct file_lock_core *flc)
|
| 696 | {
|
| 697 | struct file_lock_list_struct *fll = this_cpu_ptr(&file_lock_list);
|
| 698 |
|
| 699 | percpu_rwsem_assert_held(&file_rwsem);
|
| 700 |
|
| 701 | spin_lock(&fll->lock);
|
| 702 | flc->flc_link_cpu = smp_processor_id();
|
| 703 | hlist_add_head(&flc->flc_link, &fll->hlist);
|
| 704 | spin_unlock(&fll->lock);
|
| 705 | }
|
| 706 |
|
| 707 |
|
| 708 | static void locks_delete_global_locks(struct file_lock_core *flc)
|
| 709 | {
|
| 710 | struct file_lock_list_struct *fll;
|
| 711 |
|
| 712 | percpu_rwsem_assert_held(&file_rwsem);
|
| 713 |
|
| 714 | |
| 715 | * Avoid taking lock if already unhashed. This is safe since this check
|
| 716 | * is done while holding the flc_lock, and new insertions into the list
|
| 717 | * also require that it be held.
|
| 718 |
|
| 719 | if (hlist_unhashed(&flc->flc_link))
|
| 720 | return;
|
| 721 |
|
| 722 | fll = per_cpu_ptr(&file_lock_list, flc->flc_link_cpu);
|
| 723 | spin_lock(&fll->lock);
|
| 724 | hlist_del_init(&flc->flc_link);
|
| 725 | spin_unlock(&fll->lock);
|
| 726 | }
|
| 727 |
|
| 728 | static unsigned long
|
| 729 | posix_owner_key(struct file_lock_core *flc)
|
| 730 | {
|
| 731 | return (unsigned long) flc->flc_owner;
|
| 732 | }
|
| 733 |
|
| 734 | static void locks_insert_global_blocked(struct file_lock_core *waiter)
|
| 735 | {
|
| 736 | lockdep_assert_held(&blocked_lock_lock);
|
| 737 |
|
| 738 | hash_add(blocked_hash, &waiter->flc_link, posix_owner_key(waiter));
|
| 739 | }
|
| 740 |
|
| 741 | static void locks_delete_global_blocked(struct file_lock_core *waiter)
|
| 742 | {
|
| 743 | lockdep_assert_held(&blocked_lock_lock);
|
| 744 |
|
| 745 | hash_del(&waiter->flc_link);
|
| 746 | }
|
| 747 |
|
| 748 | |
| 749 | * When blocker ends up pointing to itself then the list is empty.
|
| 750 | *
|
| 751 | * Must be called with blocked_lock_lock held.
|
| 752 |
|
| 753 | static void __locks_unlink_block(struct file_lock_core *waiter)
|
| 754 | {
|
| 755 | locks_delete_global_blocked(waiter);
|
| 756 | list_del_init(&waiter->flc_blocked_member);
|
| 757 | }
|
| 758 |
|
| 759 | static void __locks_wake_up_blocks(struct file_lock_core *blocker)
|
| 760 | {
|
| 761 | while (!list_empty(&blocker->flc_blocked_requests)) {
|
| 762 | struct file_lock_core *waiter;
|
| 763 | struct file_lock *fl;
|
| 764 |
|
| 765 | waiter = list_first_entry(&blocker->flc_blocked_requests,
|
| 766 | struct file_lock_core, flc_blocked_member);
|
| 767 |
|
| 768 | fl = file_lock(waiter);
|
| 769 | __locks_unlink_block(waiter);
|
| 770 | if ((waiter->flc_flags & (FL_POSIX | FL_FLOCK)) &&
|
| 771 | fl->fl_lmops && fl->fl_lmops->lm_notify)
|
| 772 | fl->fl_lmops->lm_notify(fl);
|
| 773 | else
|
| 774 | locks_wake_up_waiter(waiter);
|
| 775 |
|
| 776 | |
| 777 | * The setting of flc_blocker to NULL marks the "done"
|
| 778 | * point in deleting a block. Paired with acquire at the top
|
| 779 | * of locks_delete_block().
|
| 780 |
|
| 781 | smp_store_release(&waiter->flc_blocker, NULL);
|
| 782 | }
|
| 783 | }
|
| 784 |
|
| 785 | static int __locks_delete_block(struct file_lock_core *waiter)
|
| 786 | {
|
| 787 | int status = -ENOENT;
|
| 788 |
|
| 789 | |
| 790 | * If fl_blocker is NULL, it won't be set again as this thread "owns"
|
| 791 | * the lock and is the only one that might try to claim the lock.
|
| 792 | *
|
| 793 | * We use acquire/release to manage fl_blocker so that we can
|
| 794 | * optimize away taking the blocked_lock_lock in many cases.
|
| 795 | *
|
| 796 | * The smp_load_acquire guarantees two things:
|
| 797 | *
|
| 798 | * 1/ that fl_blocked_requests can be tested locklessly. If something
|
| 799 | * was recently added to that list it must have been in a locked region
|
| 800 | * *before* the locked region when fl_blocker was set to NULL.
|
| 801 | *
|
| 802 | * 2/ that no other thread is accessing 'waiter', so it is safe to free
|
| 803 | * it. __locks_wake_up_blocks is careful not to touch waiter after
|
| 804 | * fl_blocker is released.
|
| 805 | *
|
| 806 | * If a lockless check of fl_blocker shows it to be NULL, we know that
|
| 807 | * no new locks can be inserted into its fl_blocked_requests list, and
|
| 808 | * can avoid doing anything further if the list is empty.
|
| 809 |
|
| 810 | if (!smp_load_acquire(&waiter->flc_blocker) &&
|
| 811 | list_empty(&waiter->flc_blocked_requests))
|
| 812 | return status;
|
| 813 |
|
| 814 | spin_lock(&blocked_lock_lock);
|
| 815 | if (waiter->flc_blocker)
|
| 816 | status = 0;
|
| 817 | __locks_wake_up_blocks(waiter);
|
| 818 | __locks_unlink_block(waiter);
|
| 819 |
|
| 820 | |
| 821 | * The setting of fl_blocker to NULL marks the "done" point in deleting
|
| 822 | * a block. Paired with acquire at the top of this function.
|
| 823 |
|
| 824 | smp_store_release(&waiter->flc_blocker, NULL);
|
| 825 | spin_unlock(&blocked_lock_lock);
|
| 826 | return status;
|
| 827 | }
|
| 828 |
|
| 829 | |
| 830 | * locks_delete_block - stop waiting for a file lock
|
| 831 | * @waiter: the lock which was waiting
|
| 832 | *
|
| 833 | * lockd/nfsd need to disconnect the lock while working on it.
|
| 834 |
|
| 835 | int locks_delete_block(struct file_lock *waiter)
|
| 836 | {
|
| 837 | return __locks_delete_block(&waiter->c);
|
| 838 | }
|
| 839 | EXPORT_SYMBOL(locks_delete_block);
|
| 840 |
|
| 841 | |
| 842 | * We use a circular list so that processes can be easily woken up in
|
| 843 | * the order they blocked. The documentation doesn't require this but
|
| 844 | * it seems like the reasonable thing to do.
|
| 845 | *
|
| 846 | * Must be called with both the flc_lock and blocked_lock_lock held. The
|
| 847 | * fl_blocked_requests list itself is protected by the blocked_lock_lock,
|
| 848 | * but by ensuring that the flc_lock is also held on insertions we can avoid
|
| 849 | * taking the blocked_lock_lock in some cases when we see that the
|
| 850 | * fl_blocked_requests list is empty.
|
| 851 | *
|
| 852 | * Rather than just adding to the list, we check for conflicts with any existing
|
| 853 | * waiters, and add beneath any waiter that blocks the new waiter.
|
| 854 | * Thus wakeups don't happen until needed.
|
| 855 |
|
| 856 | static void __locks_insert_block(struct file_lock_core *blocker,
|
| 857 | struct file_lock_core *waiter,
|
| 858 | bool conflict(struct file_lock_core *,
|
| 859 | struct file_lock_core *))
|
| 860 | {
|
| 861 | struct file_lock_core *flc;
|
| 862 |
|
| 863 | BUG_ON(!list_empty(&waiter->flc_blocked_member));
|
| 864 | new_blocker:
|
| 865 | list_for_each_entry(flc, &blocker->flc_blocked_requests, flc_blocked_member)
|
| 866 | if (conflict(flc, waiter)) {
|
| 867 | blocker = flc;
|
| 868 | goto new_blocker;
|
| 869 | }
|
| 870 | waiter->flc_blocker = blocker;
|
| 871 | list_add_tail(&waiter->flc_blocked_member,
|
| 872 | &blocker->flc_blocked_requests);
|
| 873 |
|
| 874 | if ((blocker->flc_flags & (FL_POSIX|FL_OFDLCK)) == FL_POSIX)
|
| 875 | locks_insert_global_blocked(waiter);
|
| 876 |
|
| 877 | |
| 878 | * waiter, but might not conflict with blocker, or the requests
|
| 879 | * and lock which block it. So they all need to be woken.
|
| 880 |
|
| 881 | __locks_wake_up_blocks(waiter);
|
| 882 | }
|
| 883 |
|
| 884 |
|
| 885 | static void locks_insert_block(struct file_lock_core *blocker,
|
| 886 | struct file_lock_core *waiter,
|
| 887 | bool conflict(struct file_lock_core *,
|
| 888 | struct file_lock_core *))
|
| 889 | {
|
| 890 | spin_lock(&blocked_lock_lock);
|
| 891 | __locks_insert_block(blocker, waiter, conflict);
|
| 892 | spin_unlock(&blocked_lock_lock);
|
| 893 | }
|
| 894 |
|
| 895 | |
| 896 | * Wake up processes blocked waiting for blocker.
|
| 897 | *
|
| 898 | * Must be called with the inode->flc_lock held!
|
| 899 |
|
| 900 | static void locks_wake_up_blocks(struct file_lock_core *blocker)
|
| 901 | {
|
| 902 | |
| 903 | * Avoid taking global lock if list is empty. This is safe since new
|
| 904 | * blocked requests are only added to the list under the flc_lock, and
|
| 905 | * the flc_lock is always held here. Note that removal from the
|
| 906 | * fl_blocked_requests list does not require the flc_lock, so we must
|
| 907 | * recheck list_empty() after acquiring the blocked_lock_lock.
|
| 908 |
|
| 909 | if (list_empty(&blocker->flc_blocked_requests))
|
| 910 | return;
|
| 911 |
|
| 912 | spin_lock(&blocked_lock_lock);
|
| 913 | __locks_wake_up_blocks(blocker);
|
| 914 | spin_unlock(&blocked_lock_lock);
|
| 915 | }
|
| 916 |
|
| 917 | static void
|
| 918 | locks_insert_lock_ctx(struct file_lock_core *fl, struct list_head *before)
|
| 919 | {
|
| 920 | list_add_tail(&fl->flc_list, before);
|
| 921 | locks_insert_global_locks(fl);
|
| 922 | }
|
| 923 |
|
| 924 | static void
|
| 925 | locks_unlink_lock_ctx(struct file_lock_core *fl)
|
| 926 | {
|
| 927 | locks_delete_global_locks(fl);
|
| 928 | list_del_init(&fl->flc_list);
|
| 929 | locks_wake_up_blocks(fl);
|
| 930 | }
|
| 931 |
|
| 932 | static void
|
| 933 | locks_delete_lock_ctx(struct file_lock_core *fl, struct list_head *dispose)
|
| 934 | {
|
| 935 | locks_unlink_lock_ctx(fl);
|
| 936 | if (dispose)
|
| 937 | list_add(&fl->flc_list, dispose);
|
| 938 | else
|
| 939 | locks_free_lock(file_lock(fl));
|
| 940 | }
|
| 941 |
|
| 942 | |
| 943 | * checks for shared/exclusive status of overlapping locks.
|
| 944 |
|
| 945 | static bool locks_conflict(struct file_lock_core *caller_flc,
|
| 946 | struct file_lock_core *sys_flc)
|
| 947 | {
|
| 948 | if (sys_flc->flc_type == F_WRLCK)
|
| 949 | return true;
|
| 950 | if (caller_flc->flc_type == F_WRLCK)
|
| 951 | return true;
|
| 952 | return false;
|
| 953 | }
|
| 954 |
|
| 955 | |
| 956 | * checking before calling the locks_conflict().
|
| 957 |
|
| 958 | static bool posix_locks_conflict(struct file_lock_core *caller_flc,
|
| 959 | struct file_lock_core *sys_flc)
|
| 960 | {
|
| 961 | struct file_lock *caller_fl = file_lock(caller_flc);
|
| 962 | struct file_lock *sys_fl = file_lock(sys_flc);
|
| 963 |
|
| 964 | |
| 965 | * each other.
|
| 966 |
|
| 967 | if (posix_same_owner(caller_flc, sys_flc))
|
| 968 | return false;
|
| 969 |
|
| 970 |
|
| 971 | if (!locks_overlap(caller_fl, sys_fl))
|
| 972 | return false;
|
| 973 |
|
| 974 | return locks_conflict(caller_flc, sys_flc);
|
| 975 | }
|
| 976 |
|
| 977 | |
| 978 | * path so checks for additional GETLK-specific things like F_UNLCK.
|
| 979 |
|
| 980 | static bool posix_test_locks_conflict(struct file_lock *caller_fl,
|
| 981 | struct file_lock *sys_fl)
|
| 982 | {
|
| 983 | struct file_lock_core *caller = &caller_fl->c;
|
| 984 | struct file_lock_core *sys = &sys_fl->c;
|
| 985 |
|
| 986 |
|
| 987 | if (lock_is_unlock(caller_fl)) {
|
| 988 | if (!posix_same_owner(caller, sys))
|
| 989 | return false;
|
| 990 | return locks_overlap(caller_fl, sys_fl);
|
| 991 | }
|
| 992 | return posix_locks_conflict(caller, sys);
|
| 993 | }
|
| 994 |
|
| 995 | |
| 996 | * checking before calling the locks_conflict().
|
| 997 |
|
| 998 | static bool flock_locks_conflict(struct file_lock_core *caller_flc,
|
| 999 | struct file_lock_core *sys_flc)
|
| 1000 | {
|
| 1001 | |
| 1002 | * each other.
|
| 1003 |
|
| 1004 | if (caller_flc->flc_file == sys_flc->flc_file)
|
| 1005 | return false;
|
| 1006 |
|
| 1007 | return locks_conflict(caller_flc, sys_flc);
|
| 1008 | }
|
| 1009 |
|
| 1010 | void
|
| 1011 | posix_test_lock(struct file *filp, struct file_lock *fl)
|
| 1012 | {
|
| 1013 | struct file_lock *cfl;
|
| 1014 | struct file_lock_context *ctx;
|
| 1015 | struct inode *inode = file_inode(filp);
|
| 1016 | void *owner;
|
| 1017 | void (*func)(void);
|
| 1018 |
|
| 1019 | ctx = locks_inode_context(inode);
|
| 1020 | if (!ctx || list_empty_careful(&ctx->flc_posix)) {
|
| 1021 | fl->c.flc_type = F_UNLCK;
|
| 1022 | return;
|
| 1023 | }
|
| 1024 |
|
| 1025 | retry:
|
| 1026 | spin_lock(&ctx->flc_lock);
|
| 1027 | list_for_each_entry(cfl, &ctx->flc_posix, c.flc_list) {
|
| 1028 | if (!posix_test_locks_conflict(fl, cfl))
|
| 1029 | continue;
|
| 1030 | if (cfl->fl_lmops && cfl->fl_lmops->lm_lock_expirable
|
| 1031 | && (*cfl->fl_lmops->lm_lock_expirable)(cfl)) {
|
| 1032 | owner = cfl->fl_lmops->lm_mod_owner;
|
| 1033 | func = cfl->fl_lmops->lm_expire_lock;
|
| 1034 | __module_get(owner);
|
| 1035 | spin_unlock(&ctx->flc_lock);
|
| 1036 | (*func)();
|
| 1037 | module_put(owner);
|
| 1038 | goto retry;
|
| 1039 | }
|
| 1040 | locks_copy_conflock(fl, cfl);
|
| 1041 | goto out;
|
| 1042 | }
|
| 1043 | fl->c.flc_type = F_UNLCK;
|
| 1044 | out:
|
| 1045 | spin_unlock(&ctx->flc_lock);
|
| 1046 | return;
|
| 1047 | }
|
| 1048 | EXPORT_SYMBOL(posix_test_lock);
|
| 1049 |
|
| 1050 | |
| 1051 | * Deadlock detection:
|
| 1052 | *
|
| 1053 | * We attempt to detect deadlocks that are due purely to posix file
|
| 1054 | * locks.
|
| 1055 | *
|
| 1056 | * We assume that a task can be waiting for at most one lock at a time.
|
| 1057 | * So for any acquired lock, the process holding that lock may be
|
| 1058 | * waiting on at most one other lock. That lock in turns may be held by
|
| 1059 | * someone waiting for at most one other lock. Given a requested lock
|
| 1060 | * caller_fl which is about to wait for a conflicting lock block_fl, we
|
| 1061 | * follow this chain of waiters to ensure we are not about to create a
|
| 1062 | * cycle.
|
| 1063 | *
|
| 1064 | * Since we do this before we ever put a process to sleep on a lock, we
|
| 1065 | * are ensured that there is never a cycle; that is what guarantees that
|
| 1066 | * the while() loop in posix_locks_deadlock() eventually completes.
|
| 1067 | *
|
| 1068 | * Note: the above assumption may not be true when handling lock
|
| 1069 | * requests from a broken NFS client. It may also fail in the presence
|
| 1070 | * of tasks (such as posix threads) sharing the same open file table.
|
| 1071 | * To handle those cases, we just bail out after a few iterations.
|
| 1072 | *
|
| 1073 | * For FL_OFDLCK locks, the owner is the filp, not the files_struct.
|
| 1074 | * Because the owner is not even nominally tied to a thread of
|
| 1075 | * execution, the deadlock detection below can't reasonably work well. Just
|
| 1076 | * skip it for those.
|
| 1077 | *
|
| 1078 | * In principle, we could do a more limited deadlock detection on FL_OFDLCK
|
| 1079 | * locks that just checks for the case where two tasks are attempting to
|
| 1080 | * upgrade from read to write locks on the same inode.
|
| 1081 |
|
| 1082 |
|
| 1083 | #define MAX_DEADLK_ITERATIONS 10
|
| 1084 |
|
| 1085 |
|
| 1086 | static struct file_lock_core *what_owner_is_waiting_for(struct file_lock_core *blocker)
|
| 1087 | {
|
| 1088 | struct file_lock_core *flc;
|
| 1089 |
|
| 1090 | hash_for_each_possible(blocked_hash, flc, flc_link, posix_owner_key(blocker)) {
|
| 1091 | if (posix_same_owner(flc, blocker)) {
|
| 1092 | while (flc->flc_blocker)
|
| 1093 | flc = flc->flc_blocker;
|
| 1094 | return flc;
|
| 1095 | }
|
| 1096 | }
|
| 1097 | return NULL;
|
| 1098 | }
|
| 1099 |
|
| 1100 |
|
| 1101 | static bool posix_locks_deadlock(struct file_lock *caller_fl,
|
| 1102 | struct file_lock *block_fl)
|
| 1103 | {
|
| 1104 | struct file_lock_core *caller = &caller_fl->c;
|
| 1105 | struct file_lock_core *blocker = &block_fl->c;
|
| 1106 | int i = 0;
|
| 1107 |
|
| 1108 | lockdep_assert_held(&blocked_lock_lock);
|
| 1109 |
|
| 1110 | |
| 1111 | * This deadlock detector can't reasonably detect deadlocks with
|
| 1112 | * FL_OFDLCK locks, since they aren't owned by a process, per-se.
|
| 1113 |
|
| 1114 | if (caller->flc_flags & FL_OFDLCK)
|
| 1115 | return false;
|
| 1116 |
|
| 1117 | while ((blocker = what_owner_is_waiting_for(blocker))) {
|
| 1118 | if (i++ > MAX_DEADLK_ITERATIONS)
|
| 1119 | return false;
|
| 1120 | if (posix_same_owner(caller, blocker))
|
| 1121 | return true;
|
| 1122 | }
|
| 1123 | return false;
|
| 1124 | }
|
| 1125 |
|
| 1126 | |
| 1127 | * after any leases, but before any posix locks.
|
| 1128 | *
|
| 1129 | * Note that if called with an FL_EXISTS argument, the caller may determine
|
| 1130 | * whether or not a lock was successfully freed by testing the return
|
| 1131 | * value for -ENOENT.
|
| 1132 |
|
| 1133 | static int flock_lock_inode(struct inode *inode, struct file_lock *request)
|
| 1134 | {
|
| 1135 | struct file_lock *new_fl = NULL;
|
| 1136 | struct file_lock *fl;
|
| 1137 | struct file_lock_context *ctx;
|
| 1138 | int error = 0;
|
| 1139 | bool found = false;
|
| 1140 | LIST_HEAD(dispose);
|
| 1141 |
|
| 1142 | ctx = locks_get_lock_context(inode, request->c.flc_type);
|
| 1143 | if (!ctx) {
|
| 1144 | if (request->c.flc_type != F_UNLCK)
|
| 1145 | return -ENOMEM;
|
| 1146 | return (request->c.flc_flags & FL_EXISTS) ? -ENOENT : 0;
|
| 1147 | }
|
| 1148 |
|
| 1149 | if (!(request->c.flc_flags & FL_ACCESS) && (request->c.flc_type != F_UNLCK)) {
|
| 1150 | new_fl = locks_alloc_lock();
|
| 1151 | if (!new_fl)
|
| 1152 | return -ENOMEM;
|
| 1153 | }
|
| 1154 |
|
| 1155 | percpu_down_read(&file_rwsem);
|
| 1156 | spin_lock(&ctx->flc_lock);
|
| 1157 | if (request->c.flc_flags & FL_ACCESS)
|
| 1158 | goto find_conflict;
|
| 1159 |
|
| 1160 | list_for_each_entry(fl, &ctx->flc_flock, c.flc_list) {
|
| 1161 | if (request->c.flc_file != fl->c.flc_file)
|
| 1162 | continue;
|
| 1163 | if (request->c.flc_type == fl->c.flc_type)
|
| 1164 | goto out;
|
| 1165 | found = true;
|
| 1166 | locks_delete_lock_ctx(&fl->c, &dispose);
|
| 1167 | break;
|
| 1168 | }
|
| 1169 |
|
| 1170 | if (lock_is_unlock(request)) {
|
| 1171 | if ((request->c.flc_flags & FL_EXISTS) && !found)
|
| 1172 | error = -ENOENT;
|
| 1173 | goto out;
|
| 1174 | }
|
| 1175 |
|
| 1176 | find_conflict:
|
| 1177 | list_for_each_entry(fl, &ctx->flc_flock, c.flc_list) {
|
| 1178 | if (!flock_locks_conflict(&request->c, &fl->c))
|
| 1179 | continue;
|
| 1180 | error = -EAGAIN;
|
| 1181 | if (!(request->c.flc_flags & FL_SLEEP))
|
| 1182 | goto out;
|
| 1183 | error = FILE_LOCK_DEFERRED;
|
| 1184 | locks_insert_block(&fl->c, &request->c, flock_locks_conflict);
|
| 1185 | goto out;
|
| 1186 | }
|
| 1187 | if (request->c.flc_flags & FL_ACCESS)
|
| 1188 | goto out;
|
| 1189 | locks_copy_lock(new_fl, request);
|
| 1190 | locks_move_blocks(new_fl, request);
|
| 1191 | locks_insert_lock_ctx(&new_fl->c, &ctx->flc_flock);
|
| 1192 | new_fl = NULL;
|
| 1193 | error = 0;
|
| 1194 |
|
| 1195 | out:
|
| 1196 | spin_unlock(&ctx->flc_lock);
|
| 1197 | percpu_up_read(&file_rwsem);
|
| 1198 | if (new_fl)
|
| 1199 | locks_free_lock(new_fl);
|
| 1200 | locks_dispose_list(&dispose);
|
| 1201 | trace_flock_lock_inode(inode, request, error);
|
| 1202 | return error;
|
| 1203 | }
|
| 1204 |
|
| 1205 | static int posix_lock_inode(struct inode *inode, struct file_lock *request,
|
| 1206 | struct file_lock *conflock)
|
| 1207 | {
|
| 1208 | struct file_lock *fl, *tmp;
|
| 1209 | struct file_lock *new_fl = NULL;
|
| 1210 | struct file_lock *new_fl2 = NULL;
|
| 1211 | struct file_lock *left = NULL;
|
| 1212 | struct file_lock *right = NULL;
|
| 1213 | struct file_lock_context *ctx;
|
| 1214 | int error;
|
| 1215 | bool added = false;
|
| 1216 | LIST_HEAD(dispose);
|
| 1217 | void *owner;
|
| 1218 | void (*func)(void);
|
| 1219 |
|
| 1220 | ctx = locks_get_lock_context(inode, request->c.flc_type);
|
| 1221 | if (!ctx)
|
| 1222 | return lock_is_unlock(request) ? 0 : -ENOMEM;
|
| 1223 |
|
| 1224 | |
| 1225 | * We may need two file_lock structures for this operation,
|
| 1226 | * so we get them in advance to avoid races.
|
| 1227 | *
|
| 1228 | * In some cases we can be sure, that no new locks will be needed
|
| 1229 |
|
| 1230 | if (!(request->c.flc_flags & FL_ACCESS) &&
|
| 1231 | (request->c.flc_type != F_UNLCK ||
|
| 1232 | request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
|
| 1233 | new_fl = locks_alloc_lock();
|
| 1234 | new_fl2 = locks_alloc_lock();
|
| 1235 | }
|
| 1236 |
|
| 1237 | retry:
|
| 1238 | percpu_down_read(&file_rwsem);
|
| 1239 | spin_lock(&ctx->flc_lock);
|
| 1240 | |
| 1241 | * New lock request. Walk all POSIX locks and look for conflicts. If
|
| 1242 | * there are any, either return error or put the request on the
|
| 1243 | * blocker's list of waiters and the global blocked_hash.
|
| 1244 |
|
| 1245 | if (request->c.flc_type != F_UNLCK) {
|
| 1246 | list_for_each_entry(fl, &ctx->flc_posix, c.flc_list) {
|
| 1247 | if (!posix_locks_conflict(&request->c, &fl->c))
|
| 1248 | continue;
|
| 1249 | if (fl->fl_lmops && fl->fl_lmops->lm_lock_expirable
|
| 1250 | && (*fl->fl_lmops->lm_lock_expirable)(fl)) {
|
| 1251 | owner = fl->fl_lmops->lm_mod_owner;
|
| 1252 | func = fl->fl_lmops->lm_expire_lock;
|
| 1253 | __module_get(owner);
|
| 1254 | spin_unlock(&ctx->flc_lock);
|
| 1255 | percpu_up_read(&file_rwsem);
|
| 1256 | (*func)();
|
| 1257 | module_put(owner);
|
| 1258 | goto retry;
|
| 1259 | }
|
| 1260 | if (conflock)
|
| 1261 | locks_copy_conflock(conflock, fl);
|
| 1262 | error = -EAGAIN;
|
| 1263 | if (!(request->c.flc_flags & FL_SLEEP))
|
| 1264 | goto out;
|
| 1265 | |
| 1266 | * Deadlock detection and insertion into the blocked
|
| 1267 | * locks list must be done while holding the same lock!
|
| 1268 |
|
| 1269 | error = -EDEADLK;
|
| 1270 | spin_lock(&blocked_lock_lock);
|
| 1271 | |
| 1272 | * Ensure that we don't find any locks blocked on this
|
| 1273 | * request during deadlock detection.
|
| 1274 |
|
| 1275 | __locks_wake_up_blocks(&request->c);
|
| 1276 | if (likely(!posix_locks_deadlock(request, fl))) {
|
| 1277 | error = FILE_LOCK_DEFERRED;
|
| 1278 | __locks_insert_block(&fl->c, &request->c,
|
| 1279 | posix_locks_conflict);
|
| 1280 | }
|
| 1281 | spin_unlock(&blocked_lock_lock);
|
| 1282 | goto out;
|
| 1283 | }
|
| 1284 | }
|
| 1285 |
|
| 1286 |
|
| 1287 | error = 0;
|
| 1288 | if (request->c.flc_flags & FL_ACCESS)
|
| 1289 | goto out;
|
| 1290 |
|
| 1291 |
|
| 1292 | list_for_each_entry(fl, &ctx->flc_posix, c.flc_list) {
|
| 1293 | if (posix_same_owner(&request->c, &fl->c))
|
| 1294 | break;
|
| 1295 | }
|
| 1296 |
|
| 1297 |
|
| 1298 | list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, c.flc_list) {
|
| 1299 | if (!posix_same_owner(&request->c, &fl->c))
|
| 1300 | break;
|
| 1301 |
|
| 1302 |
|
| 1303 | if (request->c.flc_type == fl->c.flc_type) {
|
| 1304 | |
| 1305 | * "start - 1" rather than "end + 1". If end
|
| 1306 | * is OFFSET_MAX, end + 1 will become negative.
|
| 1307 |
|
| 1308 | if (fl->fl_end < request->fl_start - 1)
|
| 1309 | continue;
|
| 1310 | |
| 1311 | * addresses than the new one, insert the lock here.
|
| 1312 |
|
| 1313 | if (fl->fl_start - 1 > request->fl_end)
|
| 1314 | break;
|
| 1315 |
|
| 1316 | |
| 1317 | * same type and adjacent or overlapping. Make one
|
| 1318 | * lock yielding from the lower start address of both
|
| 1319 | * locks to the higher end address.
|
| 1320 |
|
| 1321 | if (fl->fl_start > request->fl_start)
|
| 1322 | fl->fl_start = request->fl_start;
|
| 1323 | else
|
| 1324 | request->fl_start = fl->fl_start;
|
| 1325 | if (fl->fl_end < request->fl_end)
|
| 1326 | fl->fl_end = request->fl_end;
|
| 1327 | else
|
| 1328 | request->fl_end = fl->fl_end;
|
| 1329 | if (added) {
|
| 1330 | locks_delete_lock_ctx(&fl->c, &dispose);
|
| 1331 | continue;
|
| 1332 | }
|
| 1333 | request = fl;
|
| 1334 | added = true;
|
| 1335 | } else {
|
| 1336 | |
| 1337 | * more complex.
|
| 1338 |
|
| 1339 | if (fl->fl_end < request->fl_start)
|
| 1340 | continue;
|
| 1341 | if (fl->fl_start > request->fl_end)
|
| 1342 | break;
|
| 1343 | if (lock_is_unlock(request))
|
| 1344 | added = true;
|
| 1345 | if (fl->fl_start < request->fl_start)
|
| 1346 | left = fl;
|
| 1347 | |
| 1348 | * address than the new one, insert the new one here.
|
| 1349 |
|
| 1350 | if (fl->fl_end > request->fl_end) {
|
| 1351 | right = fl;
|
| 1352 | break;
|
| 1353 | }
|
| 1354 | if (fl->fl_start >= request->fl_start) {
|
| 1355 | |
| 1356 | * one (This may happen several times).
|
| 1357 |
|
| 1358 | if (added) {
|
| 1359 | locks_delete_lock_ctx(&fl->c, &dispose);
|
| 1360 | continue;
|
| 1361 | }
|
| 1362 | |
| 1363 | * Replace the old lock with new_fl, and
|
| 1364 | * remove the old one. It's safe to do the
|
| 1365 | * insert here since we know that we won't be
|
| 1366 | * using new_fl later, and that the lock is
|
| 1367 | * just replacing an existing lock.
|
| 1368 |
|
| 1369 | error = -ENOLCK;
|
| 1370 | if (!new_fl)
|
| 1371 | goto out;
|
| 1372 | locks_copy_lock(new_fl, request);
|
| 1373 | locks_move_blocks(new_fl, request);
|
| 1374 | request = new_fl;
|
| 1375 | new_fl = NULL;
|
| 1376 | locks_insert_lock_ctx(&request->c,
|
| 1377 | &fl->c.flc_list);
|
| 1378 | locks_delete_lock_ctx(&fl->c, &dispose);
|
| 1379 | added = true;
|
| 1380 | }
|
| 1381 | }
|
| 1382 | }
|
| 1383 |
|
| 1384 | |
| 1385 | * The above code only modifies existing locks in case of merging or
|
| 1386 | * replacing. If new lock(s) need to be inserted all modifications are
|
| 1387 | * done below this, so it's safe yet to bail out.
|
| 1388 |
|
| 1389 | error = -ENOLCK;
|
| 1390 | if (right && left == right && !new_fl2)
|
| 1391 | goto out;
|
| 1392 |
|
| 1393 | error = 0;
|
| 1394 | if (!added) {
|
| 1395 | if (lock_is_unlock(request)) {
|
| 1396 | if (request->c.flc_flags & FL_EXISTS)
|
| 1397 | error = -ENOENT;
|
| 1398 | goto out;
|
| 1399 | }
|
| 1400 |
|
| 1401 | if (!new_fl) {
|
| 1402 | error = -ENOLCK;
|
| 1403 | goto out;
|
| 1404 | }
|
| 1405 | locks_copy_lock(new_fl, request);
|
| 1406 | locks_move_blocks(new_fl, request);
|
| 1407 | locks_insert_lock_ctx(&new_fl->c, &fl->c.flc_list);
|
| 1408 | fl = new_fl;
|
| 1409 | new_fl = NULL;
|
| 1410 | }
|
| 1411 | if (right) {
|
| 1412 | if (left == right) {
|
| 1413 | |
| 1414 | * so we have to use the second new lock.
|
| 1415 |
|
| 1416 | left = new_fl2;
|
| 1417 | new_fl2 = NULL;
|
| 1418 | locks_copy_lock(left, right);
|
| 1419 | locks_insert_lock_ctx(&left->c, &fl->c.flc_list);
|
| 1420 | }
|
| 1421 | right->fl_start = request->fl_end + 1;
|
| 1422 | locks_wake_up_blocks(&right->c);
|
| 1423 | }
|
| 1424 | if (left) {
|
| 1425 | left->fl_end = request->fl_start - 1;
|
| 1426 | locks_wake_up_blocks(&left->c);
|
| 1427 | }
|
| 1428 | out:
|
| 1429 | trace_posix_lock_inode(inode, request, error);
|
| 1430 | spin_unlock(&ctx->flc_lock);
|
| 1431 | percpu_up_read(&file_rwsem);
|
| 1432 | |
| 1433 | * Free any unused locks.
|
| 1434 |
|
| 1435 | if (new_fl)
|
| 1436 | locks_free_lock(new_fl);
|
| 1437 | if (new_fl2)
|
| 1438 | locks_free_lock(new_fl2);
|
| 1439 | locks_dispose_list(&dispose);
|
| 1440 |
|
| 1441 | return error;
|
| 1442 | }
|
| 1443 |
|
| 1444 | |
| 1445 | * posix_lock_file - Apply a POSIX-style lock to a file
|
| 1446 | * @filp: The file to apply the lock to
|
| 1447 | * @fl: The lock to be applied
|
| 1448 | * @conflock: Place to return a copy of the conflicting lock, if found.
|
| 1449 | *
|
| 1450 | * Add a POSIX style lock to a file.
|
| 1451 | * We merge adjacent & overlapping locks whenever possible.
|
| 1452 | * POSIX locks are sorted by owner task, then by starting address
|
| 1453 | *
|
| 1454 | * Note that if called with an FL_EXISTS argument, the caller may determine
|
| 1455 | * whether or not a lock was successfully freed by testing the return
|
| 1456 | * value for -ENOENT.
|
| 1457 |
|
| 1458 | int posix_lock_file(struct file *filp, struct file_lock *fl,
|
| 1459 | struct file_lock *conflock)
|
| 1460 | {
|
| 1461 | return posix_lock_inode(file_inode(filp), fl, conflock);
|
| 1462 | }
|
| 1463 | EXPORT_SYMBOL(posix_lock_file);
|
| 1464 |
|
| 1465 | |
| 1466 | * posix_lock_inode_wait - Apply a POSIX-style lock to a file
|
| 1467 | * @inode: inode of file to which lock request should be applied
|
| 1468 | * @fl: The lock to be applied
|
| 1469 | *
|
| 1470 | * Apply a POSIX style lock request to an inode.
|
| 1471 |
|
| 1472 | static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
|
| 1473 | {
|
| 1474 | int error;
|
| 1475 | might_sleep ();
|
| 1476 | for (;;) {
|
| 1477 | error = posix_lock_inode(inode, fl, NULL);
|
| 1478 | if (error != FILE_LOCK_DEFERRED)
|
| 1479 | break;
|
| 1480 | error = wait_event_interruptible(fl->c.flc_wait,
|
| 1481 | list_empty(&fl->c.flc_blocked_member));
|
| 1482 | if (error)
|
| 1483 | break;
|
| 1484 | }
|
| 1485 | locks_delete_block(fl);
|
| 1486 | return error;
|
| 1487 | }
|
| 1488 |
|
| 1489 | static void lease_clear_pending(struct file_lease *fl, int arg)
|
| 1490 | {
|
| 1491 | switch (arg) {
|
| 1492 | case F_UNLCK:
|
| 1493 | fl->c.flc_flags &= ~FL_UNLOCK_PENDING;
|
| 1494 | fallthrough;
|
| 1495 | case F_RDLCK:
|
| 1496 | fl->c.flc_flags &= ~FL_DOWNGRADE_PENDING;
|
| 1497 | }
|
| 1498 | }
|
| 1499 |
|
| 1500 |
|
| 1501 | int lease_modify(struct file_lease *fl, int arg, struct list_head *dispose)
|
| 1502 | {
|
| 1503 | int error = assign_type(&fl->c, arg);
|
| 1504 |
|
| 1505 | if (error)
|
| 1506 | return error;
|
| 1507 | lease_clear_pending(fl, arg);
|
| 1508 | locks_wake_up_blocks(&fl->c);
|
| 1509 | if (arg == F_UNLCK) {
|
| 1510 | struct file *filp = fl->c.flc_file;
|
| 1511 |
|
| 1512 | f_delown(filp);
|
| 1513 | file_f_owner(filp)->signum = 0;
|
| 1514 | fasync_helper(0, fl->c.flc_file, 0, &fl->fl_fasync);
|
| 1515 | if (fl->fl_fasync != NULL) {
|
| 1516 | printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync);
|
| 1517 | fl->fl_fasync = NULL;
|
| 1518 | }
|
| 1519 | locks_delete_lock_ctx(&fl->c, dispose);
|
| 1520 | }
|
| 1521 | return 0;
|
| 1522 | }
|
| 1523 | EXPORT_SYMBOL(lease_modify);
|
| 1524 |
|
| 1525 | static bool past_time(unsigned long then)
|
| 1526 | {
|
| 1527 | if (!then)
|
| 1528 |
|
| 1529 | return false;
|
| 1530 | return time_after(jiffies, then);
|
| 1531 | }
|
| 1532 |
|
| 1533 | static void time_out_leases(struct inode *inode, struct list_head *dispose)
|
| 1534 | {
|
| 1535 | struct file_lock_context *ctx = inode->i_flctx;
|
| 1536 | struct file_lease *fl, *tmp;
|
| 1537 | bool remove;
|
| 1538 |
|
| 1539 | lockdep_assert_held(&ctx->flc_lock);
|
| 1540 |
|
| 1541 | list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, c.flc_list) {
|
| 1542 | trace_time_out_leases(inode, fl);
|
| 1543 | if (past_time(fl->fl_downgrade_time))
|
| 1544 | lease_modify(fl, F_RDLCK, dispose);
|
| 1545 |
|
| 1546 | remove = true;
|
| 1547 | if (past_time(fl->fl_break_time)) {
|
| 1548 | |
| 1549 | * Consult the lease manager when a lease break times
|
| 1550 | * out to determine whether the lease should be disposed
|
| 1551 | * of.
|
| 1552 |
|
| 1553 | if (fl->fl_lmops && fl->fl_lmops->lm_breaker_timedout)
|
| 1554 | remove = fl->fl_lmops->lm_breaker_timedout(fl);
|
| 1555 | if (remove)
|
| 1556 | lease_modify(fl, F_UNLCK, dispose);
|
| 1557 | }
|
| 1558 | }
|
| 1559 | }
|
| 1560 |
|
| 1561 | static bool leases_conflict(struct file_lock_core *lc, struct file_lock_core *bc)
|
| 1562 | {
|
| 1563 | bool rc;
|
| 1564 | struct file_lease *lease = file_lease(lc);
|
| 1565 | struct file_lease *breaker = file_lease(bc);
|
| 1566 |
|
| 1567 | if (lease->fl_lmops->lm_breaker_owns_lease
|
| 1568 | && lease->fl_lmops->lm_breaker_owns_lease(lease))
|
| 1569 | return false;
|
| 1570 | if ((bc->flc_flags & FL_LAYOUT) != (lc->flc_flags & FL_LAYOUT)) {
|
| 1571 | rc = false;
|
| 1572 | goto trace;
|
| 1573 | }
|
| 1574 | if ((bc->flc_flags & FL_DELEG) && (lc->flc_flags & FL_LEASE)) {
|
| 1575 | rc = false;
|
| 1576 | goto trace;
|
| 1577 | }
|
| 1578 |
|
| 1579 | rc = locks_conflict(bc, lc);
|
| 1580 | trace:
|
| 1581 | trace_leases_conflict(rc, lease, breaker);
|
| 1582 | return rc;
|
| 1583 | }
|
| 1584 |
|
| 1585 | #define IGNORE_MASK (FL_IGN_DIR_CREATE | FL_IGN_DIR_DELETE | FL_IGN_DIR_RENAME)
|
| 1586 |
|
| 1587 | |
| 1588 | * inode_lease_ignore_mask - return union of all ignored inode events for this inode
|
| 1589 | * @inode: inode of which to get ignore mask
|
| 1590 | *
|
| 1591 | * Walk the list of leases, and return the result of all of
|
| 1592 | * their FL_IGN_DIR_* bits or'ed together.
|
| 1593 |
|
| 1594 | u32
|
| 1595 | inode_lease_ignore_mask(struct inode *inode)
|
| 1596 | {
|
| 1597 | struct file_lock_context *ctx;
|
| 1598 | struct file_lock_core *flc;
|
| 1599 | u32 mask = 0;
|
| 1600 |
|
| 1601 | ctx = locks_inode_context(inode);
|
| 1602 | if (!ctx)
|
| 1603 | return 0;
|
| 1604 |
|
| 1605 | spin_lock(&ctx->flc_lock);
|
| 1606 | list_for_each_entry(flc, &ctx->flc_lease, flc_list) {
|
| 1607 | mask |= flc->flc_flags & IGNORE_MASK;
|
| 1608 |
|
| 1609 | if (mask == IGNORE_MASK)
|
| 1610 | break;
|
| 1611 | }
|
| 1612 | spin_unlock(&ctx->flc_lock);
|
| 1613 | return mask;
|
| 1614 | }
|
| 1615 | EXPORT_SYMBOL_GPL(inode_lease_ignore_mask);
|
| 1616 |
|
| 1617 | static bool
|
| 1618 | ignore_dir_deleg_break(struct file_lease *fl, unsigned int flags)
|
| 1619 | {
|
| 1620 | if ((flags & LEASE_BREAK_DIR_CREATE) && (fl->c.flc_flags & FL_IGN_DIR_CREATE))
|
| 1621 | return true;
|
| 1622 | if ((flags & LEASE_BREAK_DIR_DELETE) && (fl->c.flc_flags & FL_IGN_DIR_DELETE))
|
| 1623 | return true;
|
| 1624 | if ((flags & LEASE_BREAK_DIR_RENAME) && (fl->c.flc_flags & FL_IGN_DIR_RENAME))
|
| 1625 | return true;
|
| 1626 |
|
| 1627 | return false;
|
| 1628 | }
|
| 1629 |
|
| 1630 | static unsigned int
|
| 1631 | break_lease_flags_to_type(unsigned int flags)
|
| 1632 | {
|
| 1633 | if (flags & LEASE_BREAK_LEASE)
|
| 1634 | return FL_LEASE;
|
| 1635 | else if (flags & LEASE_BREAK_DELEG)
|
| 1636 | return FL_DELEG;
|
| 1637 | else if (flags & LEASE_BREAK_LAYOUT)
|
| 1638 | return FL_LAYOUT;
|
| 1639 | else
|
| 1640 | return 0;
|
| 1641 |
|
| 1642 | }
|
| 1643 |
|
| 1644 | static struct file_lease *
|
| 1645 | first_visible_lease(struct inode *inode, struct file_lease *new_fl, unsigned int flags)
|
| 1646 | {
|
| 1647 | struct file_lock_context *ctx = locks_inode_context(inode);
|
| 1648 | struct file_lease *fl;
|
| 1649 |
|
| 1650 | lockdep_assert_held(&ctx->flc_lock);
|
| 1651 |
|
| 1652 | list_for_each_entry(fl, &ctx->flc_lease, c.flc_list) {
|
| 1653 | if (!leases_conflict(&fl->c, &new_fl->c))
|
| 1654 | continue;
|
| 1655 | if (S_ISDIR(inode->i_mode) && ignore_dir_deleg_break(fl, flags))
|
| 1656 | continue;
|
| 1657 | return fl;
|
| 1658 | }
|
| 1659 | return NULL;
|
| 1660 | }
|
| 1661 |
|
| 1662 |
|
| 1663 | |
| 1664 | * __break_lease - revoke all outstanding leases on file
|
| 1665 | * @inode: the inode of the file to return
|
| 1666 | * @flags: LEASE_BREAK_* flags
|
| 1667 | *
|
| 1668 | * break_lease (inlined for speed) has checked there already is at least
|
| 1669 | * some kind of lock (maybe a lease) on this file. Leases and Delegations
|
| 1670 | * are broken on a call to open() or truncate(). Delegations are also
|
| 1671 | * broken on any event that would change the ctime. Directory delegations
|
| 1672 | * are broken whenever the directory changes (unless the delegation is set
|
| 1673 | * up to ignore the event). This function can block waiting for the lease
|
| 1674 | * break unless you specify LEASE_BREAK_NONBLOCK.
|
| 1675 |
|
| 1676 | int __break_lease(struct inode *inode, unsigned int flags)
|
| 1677 | {
|
| 1678 | struct file_lease *new_fl, *fl, *tmp;
|
| 1679 | struct file_lock_context *ctx;
|
| 1680 | unsigned long break_time;
|
| 1681 | unsigned int type;
|
| 1682 | LIST_HEAD(dispose);
|
| 1683 | bool want_write = !(flags & LEASE_BREAK_OPEN_RDONLY);
|
| 1684 | int error = 0;
|
| 1685 |
|
| 1686 | trace_break_lease(inode, flags);
|
| 1687 |
|
| 1688 | type = break_lease_flags_to_type(flags);
|
| 1689 | if (!type)
|
| 1690 | return -EINVAL;
|
| 1691 |
|
| 1692 | new_fl = lease_alloc(NULL, type, want_write ? F_WRLCK : F_RDLCK);
|
| 1693 | if (IS_ERR(new_fl))
|
| 1694 | return PTR_ERR(new_fl);
|
| 1695 |
|
| 1696 |
|
| 1697 | ctx = locks_inode_context(inode);
|
| 1698 | if (!ctx) {
|
| 1699 | WARN_ON_ONCE(1);
|
| 1700 | goto free_lock;
|
| 1701 | }
|
| 1702 |
|
| 1703 | percpu_down_read(&file_rwsem);
|
| 1704 | spin_lock(&ctx->flc_lock);
|
| 1705 |
|
| 1706 | time_out_leases(inode, &dispose);
|
| 1707 |
|
| 1708 | if (!first_visible_lease(inode, new_fl, flags))
|
| 1709 | goto out;
|
| 1710 |
|
| 1711 | break_time = 0;
|
| 1712 | if (lease_break_time > 0) {
|
| 1713 | break_time = jiffies + lease_break_time * HZ;
|
| 1714 | if (break_time == 0)
|
| 1715 | break_time++;
|
| 1716 | }
|
| 1717 |
|
| 1718 | list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, c.flc_list) {
|
| 1719 | if (!leases_conflict(&fl->c, &new_fl->c))
|
| 1720 | continue;
|
| 1721 | if (S_ISDIR(inode->i_mode) && ignore_dir_deleg_break(fl, flags))
|
| 1722 | continue;
|
| 1723 | if (want_write) {
|
| 1724 | if (fl->c.flc_flags & FL_UNLOCK_PENDING)
|
| 1725 | continue;
|
| 1726 | fl->c.flc_flags |= FL_UNLOCK_PENDING;
|
| 1727 | fl->fl_break_time = break_time;
|
| 1728 | } else {
|
| 1729 | if (lease_breaking(fl))
|
| 1730 | continue;
|
| 1731 | fl->c.flc_flags |= FL_DOWNGRADE_PENDING;
|
| 1732 | fl->fl_downgrade_time = break_time;
|
| 1733 | }
|
| 1734 | if (fl->fl_lmops->lm_break(fl))
|
| 1735 | locks_delete_lock_ctx(&fl->c, &dispose);
|
| 1736 | }
|
| 1737 |
|
| 1738 | fl = first_visible_lease(inode, new_fl, flags);
|
| 1739 | if (!fl)
|
| 1740 | goto out;
|
| 1741 |
|
| 1742 | if (flags & LEASE_BREAK_NONBLOCK) {
|
| 1743 | trace_break_lease_noblock(inode, new_fl);
|
| 1744 | error = -EWOULDBLOCK;
|
| 1745 | goto out;
|
| 1746 | }
|
| 1747 |
|
| 1748 | restart:
|
| 1749 | break_time = fl->fl_break_time;
|
| 1750 | if (break_time != 0) {
|
| 1751 | if (time_after(jiffies, break_time)) {
|
| 1752 | fl->fl_break_time = jiffies + lease_break_time * HZ;
|
| 1753 | break_time = lease_break_time * HZ;
|
| 1754 | } else
|
| 1755 | break_time -= jiffies;
|
| 1756 | } else
|
| 1757 | break_time++;
|
| 1758 | locks_insert_block(&fl->c, &new_fl->c, leases_conflict);
|
| 1759 | trace_break_lease_block(inode, fl);
|
| 1760 | spin_unlock(&ctx->flc_lock);
|
| 1761 | percpu_up_read(&file_rwsem);
|
| 1762 |
|
| 1763 | lease_dispose_list(&dispose);
|
| 1764 | error = wait_event_interruptible_timeout(new_fl->c.flc_wait,
|
| 1765 | list_empty(&new_fl->c.flc_blocked_member),
|
| 1766 | break_time);
|
| 1767 |
|
| 1768 | percpu_down_read(&file_rwsem);
|
| 1769 | spin_lock(&ctx->flc_lock);
|
| 1770 | trace_break_lease_unblock(inode, NULL);
|
| 1771 | __locks_delete_block(&new_fl->c);
|
| 1772 | if (error >= 0) {
|
| 1773 | |
| 1774 | * Wait for the next conflicting lease that has not been
|
| 1775 | * broken yet
|
| 1776 |
|
| 1777 | if (error == 0)
|
| 1778 | time_out_leases(inode, &dispose);
|
| 1779 | fl = first_visible_lease(inode, new_fl, flags);
|
| 1780 | if (fl)
|
| 1781 | goto restart;
|
| 1782 | error = 0;
|
| 1783 | }
|
| 1784 | out:
|
| 1785 | spin_unlock(&ctx->flc_lock);
|
| 1786 | percpu_up_read(&file_rwsem);
|
| 1787 | lease_dispose_list(&dispose);
|
| 1788 | free_lock:
|
| 1789 | locks_free_lease(new_fl);
|
| 1790 | return error;
|
| 1791 | }
|
| 1792 | EXPORT_SYMBOL(__break_lease);
|
| 1793 |
|
| 1794 | |
| 1795 | * lease_get_mtime - update modified time of an inode with exclusive lease
|
| 1796 | * @inode: the inode
|
| 1797 | * @time: pointer to a timespec which contains the last modified time
|
| 1798 | *
|
| 1799 | * This is to force NFS clients to flush their caches for files with
|
| 1800 | * exclusive leases. The justification is that if someone has an
|
| 1801 | * exclusive lease, then they could be modifying it.
|
| 1802 |
|
| 1803 | void lease_get_mtime(struct inode *inode, struct timespec64 *time)
|
| 1804 | {
|
| 1805 | bool has_lease = false;
|
| 1806 | struct file_lock_context *ctx;
|
| 1807 | struct file_lock_core *flc;
|
| 1808 |
|
| 1809 | ctx = locks_inode_context(inode);
|
| 1810 | if (ctx && !list_empty_careful(&ctx->flc_lease)) {
|
| 1811 | spin_lock(&ctx->flc_lock);
|
| 1812 | flc = list_first_entry_or_null(&ctx->flc_lease,
|
| 1813 | struct file_lock_core, flc_list);
|
| 1814 | if (flc && flc->flc_type == F_WRLCK)
|
| 1815 | has_lease = true;
|
| 1816 | spin_unlock(&ctx->flc_lock);
|
| 1817 | }
|
| 1818 |
|
| 1819 | if (has_lease)
|
| 1820 | *time = current_time(inode);
|
| 1821 | }
|
| 1822 | EXPORT_SYMBOL(lease_get_mtime);
|
| 1823 |
|
| 1824 | |
| 1825 | * __fcntl_getlease - Enquire what lease is currently active
|
| 1826 | * @filp: the file
|
| 1827 | * @flavor: type of lease flags to check
|
| 1828 | *
|
| 1829 | * The value returned by this function will be one of
|
| 1830 | * (if no lease break is pending):
|
| 1831 | *
|
| 1832 | * %F_RDLCK to indicate a shared lease is held.
|
| 1833 | *
|
| 1834 | * %F_WRLCK to indicate an exclusive lease is held.
|
| 1835 | *
|
| 1836 | * %F_UNLCK to indicate no lease is held.
|
| 1837 | *
|
| 1838 | * (if a lease break is pending):
|
| 1839 | *
|
| 1840 | * %F_RDLCK to indicate an exclusive lease needs to be
|
| 1841 | * changed to a shared lease (or removed).
|
| 1842 | *
|
| 1843 | * %F_UNLCK to indicate the lease needs to be removed.
|
| 1844 | *
|
| 1845 | * XXX: sfr & willy disagree over whether F_INPROGRESS
|
| 1846 | * should be returned to userspace.
|
| 1847 |
|
| 1848 | static int __fcntl_getlease(struct file *filp, unsigned int flavor)
|
| 1849 | {
|
| 1850 | struct file_lease *fl;
|
| 1851 | struct inode *inode = file_inode(filp);
|
| 1852 | struct file_lock_context *ctx;
|
| 1853 | int type = F_UNLCK;
|
| 1854 | LIST_HEAD(dispose);
|
| 1855 |
|
| 1856 | ctx = locks_inode_context(inode);
|
| 1857 | if (ctx && !list_empty_careful(&ctx->flc_lease)) {
|
| 1858 | percpu_down_read(&file_rwsem);
|
| 1859 | spin_lock(&ctx->flc_lock);
|
| 1860 | time_out_leases(inode, &dispose);
|
| 1861 | list_for_each_entry(fl, &ctx->flc_lease, c.flc_list) {
|
| 1862 | if (fl->c.flc_file != filp)
|
| 1863 | continue;
|
| 1864 | if (fl->c.flc_flags & flavor)
|
| 1865 | type = target_leasetype(fl);
|
| 1866 | break;
|
| 1867 | }
|
| 1868 | spin_unlock(&ctx->flc_lock);
|
| 1869 | percpu_up_read(&file_rwsem);
|
| 1870 |
|
| 1871 | lease_dispose_list(&dispose);
|
| 1872 | }
|
| 1873 | return type;
|
| 1874 | }
|
| 1875 |
|
| 1876 | int fcntl_getlease(struct file *filp)
|
| 1877 | {
|
| 1878 | return __fcntl_getlease(filp, FL_LEASE);
|
| 1879 | }
|
| 1880 |
|
| 1881 | int fcntl_getdeleg(struct file *filp, struct delegation *deleg)
|
| 1882 | {
|
| 1883 | if (deleg->d_flags != 0 || deleg->__pad != 0)
|
| 1884 | return -EINVAL;
|
| 1885 | deleg->d_type = __fcntl_getlease(filp, FL_DELEG);
|
| 1886 | return 0;
|
| 1887 | }
|
| 1888 |
|
| 1889 | static int
|
| 1890 | generic_add_lease(struct file *filp, int arg, struct file_lease **flp, void **priv)
|
| 1891 | {
|
| 1892 | struct file_lease *fl, *my_fl = NULL, *lease;
|
| 1893 | struct inode *inode = file_inode(filp);
|
| 1894 | struct file_lock_context *ctx;
|
| 1895 | bool is_deleg = (*flp)->c.flc_flags & FL_DELEG;
|
| 1896 | int error;
|
| 1897 | LIST_HEAD(dispose);
|
| 1898 |
|
| 1899 | lease = *flp;
|
| 1900 | trace_generic_add_lease(inode, lease);
|
| 1901 |
|
| 1902 | error = file_f_owner_allocate(filp);
|
| 1903 | if (error)
|
| 1904 | return error;
|
| 1905 |
|
| 1906 |
|
| 1907 | ctx = locks_get_lock_context(inode, arg);
|
| 1908 | if (!ctx)
|
| 1909 | return -ENOMEM;
|
| 1910 |
|
| 1911 | |
| 1912 | * In the delegation case we need mutual exclusion with
|
| 1913 | * a number of operations that take the i_rwsem. We trylock
|
| 1914 | * because delegations are an optional optimization, and if
|
| 1915 | * there's some chance of a conflict--we'd rather not
|
| 1916 | * bother, maybe that's a sign this just isn't a good file to
|
| 1917 | * hand out a delegation on.
|
| 1918 |
|
| 1919 | if (is_deleg && !inode_trylock(inode))
|
| 1920 | return -EAGAIN;
|
| 1921 |
|
| 1922 | percpu_down_read(&file_rwsem);
|
| 1923 | spin_lock(&ctx->flc_lock);
|
| 1924 | time_out_leases(inode, &dispose);
|
| 1925 | error = lease->fl_lmops->lm_open_conflict(filp, arg);
|
| 1926 | if (error)
|
| 1927 | goto out;
|
| 1928 |
|
| 1929 | |
| 1930 | * At this point, we know that if there is an exclusive
|
| 1931 | * lease on this file, then we hold it on this filp
|
| 1932 | * (otherwise our open of this file would have blocked).
|
| 1933 | * And if we are trying to acquire an exclusive lease,
|
| 1934 | * then the file is not open by anyone (including us)
|
| 1935 | * except for this filp.
|
| 1936 |
|
| 1937 | error = -EAGAIN;
|
| 1938 | list_for_each_entry(fl, &ctx->flc_lease, c.flc_list) {
|
| 1939 | if (fl->c.flc_file == filp &&
|
| 1940 | fl->c.flc_owner == lease->c.flc_owner) {
|
| 1941 | my_fl = fl;
|
| 1942 | continue;
|
| 1943 | }
|
| 1944 |
|
| 1945 | |
| 1946 | * No exclusive leases if someone else has a lease on
|
| 1947 | * this file:
|
| 1948 |
|
| 1949 | if (arg == F_WRLCK)
|
| 1950 | goto out;
|
| 1951 | |
| 1952 | * Modifying our existing lease is OK, but no getting a
|
| 1953 | * new lease if someone else is opening for write:
|
| 1954 |
|
| 1955 | if (fl->c.flc_flags & FL_UNLOCK_PENDING)
|
| 1956 | goto out;
|
| 1957 | }
|
| 1958 |
|
| 1959 | if (my_fl != NULL) {
|
| 1960 | lease = my_fl;
|
| 1961 | error = lease->fl_lmops->lm_change(lease, arg, &dispose);
|
| 1962 | if (error)
|
| 1963 | goto out;
|
| 1964 | goto out_setup;
|
| 1965 | }
|
| 1966 |
|
| 1967 | error = -EINVAL;
|
| 1968 | if (!leases_enable)
|
| 1969 | goto out;
|
| 1970 |
|
| 1971 | locks_insert_lock_ctx(&lease->c, &ctx->flc_lease);
|
| 1972 | |
| 1973 | * The check in break_lease() is lockless. It's possible for another
|
| 1974 | * open to race in after we did the earlier check for a conflicting
|
| 1975 | * open but before the lease was inserted. Check again for a
|
| 1976 | * conflicting open and cancel the lease if there is one.
|
| 1977 | *
|
| 1978 | * We also add a barrier here to ensure that the insertion of the lock
|
| 1979 | * precedes these checks.
|
| 1980 |
|
| 1981 | smp_mb();
|
| 1982 | error = lease->fl_lmops->lm_open_conflict(filp, arg);
|
| 1983 | if (error) {
|
| 1984 | locks_unlink_lock_ctx(&lease->c);
|
| 1985 | goto out;
|
| 1986 | }
|
| 1987 |
|
| 1988 | out_setup:
|
| 1989 | if (lease->fl_lmops->lm_setup)
|
| 1990 | lease->fl_lmops->lm_setup(lease, priv);
|
| 1991 | out:
|
| 1992 | spin_unlock(&ctx->flc_lock);
|
| 1993 | percpu_up_read(&file_rwsem);
|
| 1994 | lease_dispose_list(&dispose);
|
| 1995 | if (is_deleg)
|
| 1996 | inode_unlock(inode);
|
| 1997 | if (!error && !my_fl)
|
| 1998 | *flp = NULL;
|
| 1999 | return error;
|
| 2000 | }
|
| 2001 |
|
| 2002 | static int generic_delete_lease(struct file *filp, void *owner)
|
| 2003 | {
|
| 2004 | int error = -EAGAIN;
|
| 2005 | struct file_lease *fl, *victim = NULL;
|
| 2006 | struct inode *inode = file_inode(filp);
|
| 2007 | struct file_lock_context *ctx;
|
| 2008 | LIST_HEAD(dispose);
|
| 2009 |
|
| 2010 | ctx = locks_inode_context(inode);
|
| 2011 | if (!ctx) {
|
| 2012 | trace_generic_delete_lease(inode, NULL);
|
| 2013 | return error;
|
| 2014 | }
|
| 2015 |
|
| 2016 | percpu_down_read(&file_rwsem);
|
| 2017 | spin_lock(&ctx->flc_lock);
|
| 2018 | list_for_each_entry(fl, &ctx->flc_lease, c.flc_list) {
|
| 2019 | if (fl->c.flc_file == filp &&
|
| 2020 | fl->c.flc_owner == owner) {
|
| 2021 | victim = fl;
|
| 2022 | break;
|
| 2023 | }
|
| 2024 | }
|
| 2025 | trace_generic_delete_lease(inode, victim);
|
| 2026 | if (victim)
|
| 2027 | error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose);
|
| 2028 | spin_unlock(&ctx->flc_lock);
|
| 2029 | percpu_up_read(&file_rwsem);
|
| 2030 | lease_dispose_list(&dispose);
|
| 2031 | return error;
|
| 2032 | }
|
| 2033 |
|
| 2034 | |
| 2035 | * generic_setlease - sets a lease on an open file
|
| 2036 | * @filp: file pointer
|
| 2037 | * @arg: type of lease to obtain
|
| 2038 | * @flp: input - file_lock to use, output - file_lock inserted
|
| 2039 | * @priv: private data for lm_setup (may be NULL if lm_setup
|
| 2040 | * doesn't require it)
|
| 2041 | *
|
| 2042 | * The (input) flp->fl_lmops->lm_break function is required
|
| 2043 | * by break_lease().
|
| 2044 |
|
| 2045 | int generic_setlease(struct file *filp, int arg, struct file_lease **flp,
|
| 2046 | void **priv)
|
| 2047 | {
|
| 2048 | struct inode *inode = file_inode(filp);
|
| 2049 |
|
| 2050 | if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
|
| 2051 | return -EINVAL;
|
| 2052 |
|
| 2053 | switch (arg) {
|
| 2054 | case F_UNLCK:
|
| 2055 | return generic_delete_lease(filp, *priv);
|
| 2056 | case F_WRLCK:
|
| 2057 | if (S_ISDIR(inode->i_mode))
|
| 2058 | return -EINVAL;
|
| 2059 | fallthrough;
|
| 2060 | case F_RDLCK:
|
| 2061 | if (!(*flp)->fl_lmops->lm_break) {
|
| 2062 | WARN_ON_ONCE(1);
|
| 2063 | return -ENOLCK;
|
| 2064 | }
|
| 2065 |
|
| 2066 | return generic_add_lease(filp, arg, flp, priv);
|
| 2067 | default:
|
| 2068 | return -EINVAL;
|
| 2069 | }
|
| 2070 | }
|
| 2071 | EXPORT_SYMBOL(generic_setlease);
|
| 2072 |
|
| 2073 | |
| 2074 | * Kernel subsystems can register to be notified on any attempt to set
|
| 2075 | * a new lease with the lease_notifier_chain. This is used by (e.g.) nfsd
|
| 2076 | * to close files that it may have cached when there is an attempt to set a
|
| 2077 | * conflicting lease.
|
| 2078 |
|
| 2079 | static struct srcu_notifier_head lease_notifier_chain;
|
| 2080 |
|
| 2081 | static inline void
|
| 2082 | lease_notifier_chain_init(void)
|
| 2083 | {
|
| 2084 | srcu_init_notifier_head(&lease_notifier_chain);
|
| 2085 | }
|
| 2086 |
|
| 2087 | static inline void
|
| 2088 | setlease_notifier(int arg, struct file_lease *lease)
|
| 2089 | {
|
| 2090 | if (arg != F_UNLCK)
|
| 2091 | srcu_notifier_call_chain(&lease_notifier_chain, arg, lease);
|
| 2092 | }
|
| 2093 |
|
| 2094 | int lease_register_notifier(struct notifier_block *nb)
|
| 2095 | {
|
| 2096 | return srcu_notifier_chain_register(&lease_notifier_chain, nb);
|
| 2097 | }
|
| 2098 | EXPORT_SYMBOL_GPL(lease_register_notifier);
|
| 2099 |
|
| 2100 | void lease_unregister_notifier(struct notifier_block *nb)
|
| 2101 | {
|
| 2102 | srcu_notifier_chain_unregister(&lease_notifier_chain, nb);
|
| 2103 | }
|
| 2104 | EXPORT_SYMBOL_GPL(lease_unregister_notifier);
|
| 2105 |
|
| 2106 |
|
| 2107 | int
|
| 2108 | kernel_setlease(struct file *filp, int arg, struct file_lease **lease, void **priv)
|
| 2109 | {
|
| 2110 | if (lease)
|
| 2111 | setlease_notifier(arg, *lease);
|
| 2112 | if (filp->f_op->setlease)
|
| 2113 | return filp->f_op->setlease(filp, arg, lease, priv);
|
| 2114 | return -EINVAL;
|
| 2115 | }
|
| 2116 | EXPORT_SYMBOL_GPL(kernel_setlease);
|
| 2117 |
|
| 2118 | |
| 2119 | * vfs_setlease - sets a lease on an open file
|
| 2120 | * @filp: file pointer
|
| 2121 | * @arg: type of lease to obtain
|
| 2122 | * @lease: file_lock to use when adding a lease
|
| 2123 | * @priv: private info for lm_setup when adding a lease (may be
|
| 2124 | * NULL if lm_setup doesn't require it)
|
| 2125 | *
|
| 2126 | * Call this to establish a lease on the file. The "lease" argument is not
|
| 2127 | * used for F_UNLCK requests and may be NULL. For commands that set or alter
|
| 2128 | * an existing lease, the ``(*lease)->fl_lmops->lm_break`` operation must be
|
| 2129 | * set; if not, this function will return -ENOLCK (and generate a scary-looking
|
| 2130 | * stack trace).
|
| 2131 | *
|
| 2132 | * The "priv" pointer is passed directly to the lm_setup function as-is. It
|
| 2133 | * may be NULL if the lm_setup operation doesn't require it.
|
| 2134 |
|
| 2135 | int
|
| 2136 | vfs_setlease(struct file *filp, int arg, struct file_lease **lease, void **priv)
|
| 2137 | {
|
| 2138 | struct inode *inode = file_inode(filp);
|
| 2139 | vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_idmap(filp), inode);
|
| 2140 | int error;
|
| 2141 |
|
| 2142 | if ((!vfsuid_eq_kuid(vfsuid, current_fsuid())) && !capable(CAP_LEASE))
|
| 2143 | return -EACCES;
|
| 2144 | error = security_file_lock(filp, arg);
|
| 2145 | if (error)
|
| 2146 | return error;
|
| 2147 | return kernel_setlease(filp, arg, lease, priv);
|
| 2148 | }
|
| 2149 | EXPORT_SYMBOL_GPL(vfs_setlease);
|
| 2150 |
|
| 2151 | static int do_fcntl_add_lease(unsigned int fd, struct file *filp, unsigned int flavor, int arg)
|
| 2152 | {
|
| 2153 | struct file_lease *fl;
|
| 2154 | struct fasync_struct *new;
|
| 2155 | int error;
|
| 2156 |
|
| 2157 | fl = lease_alloc(filp, flavor, arg);
|
| 2158 | if (IS_ERR(fl))
|
| 2159 | return PTR_ERR(fl);
|
| 2160 |
|
| 2161 | new = fasync_alloc();
|
| 2162 | if (!new) {
|
| 2163 | locks_free_lease(fl);
|
| 2164 | return -ENOMEM;
|
| 2165 | }
|
| 2166 | new->fa_fd = fd;
|
| 2167 |
|
| 2168 | error = vfs_setlease(filp, arg, &fl, (void **)&new);
|
| 2169 | if (fl)
|
| 2170 | locks_free_lease(fl);
|
| 2171 | if (new)
|
| 2172 | fasync_free(new);
|
| 2173 | return error;
|
| 2174 | }
|
| 2175 |
|
| 2176 | |
| 2177 | * fcntl_setlease - sets a lease on an open file
|
| 2178 | * @fd: open file descriptor
|
| 2179 | * @filp: file pointer
|
| 2180 | * @arg: type of lease to obtain
|
| 2181 | *
|
| 2182 | * Call this fcntl to establish a lease on the file.
|
| 2183 | * Note that you also need to call %F_SETSIG to
|
| 2184 | * receive a signal when the lease is broken.
|
| 2185 |
|
| 2186 | int fcntl_setlease(unsigned int fd, struct file *filp, int arg)
|
| 2187 | {
|
| 2188 | if (S_ISDIR(file_inode(filp)->i_mode))
|
| 2189 | return -EINVAL;
|
| 2190 |
|
| 2191 | if (arg == F_UNLCK)
|
| 2192 | return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
|
| 2193 | return do_fcntl_add_lease(fd, filp, FL_LEASE, arg);
|
| 2194 | }
|
| 2195 |
|
| 2196 | |
| 2197 | * fcntl_setdeleg - sets a delegation on an open file
|
| 2198 | * @fd: open file descriptor
|
| 2199 | * @filp: file pointer
|
| 2200 | * @deleg: delegation request from userland
|
| 2201 | *
|
| 2202 | * Call this fcntl to establish a delegation on the file.
|
| 2203 | * Note that you also need to call %F_SETSIG to
|
| 2204 | * receive a signal when the lease is broken.
|
| 2205 |
|
| 2206 | int fcntl_setdeleg(unsigned int fd, struct file *filp, struct delegation *deleg)
|
| 2207 | {
|
| 2208 |
|
| 2209 | if (deleg->d_flags != 0 || deleg->__pad != 0)
|
| 2210 | return -EINVAL;
|
| 2211 |
|
| 2212 | if (deleg->d_type == F_UNLCK)
|
| 2213 | return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp);
|
| 2214 | return do_fcntl_add_lease(fd, filp, FL_DELEG, deleg->d_type);
|
| 2215 | }
|
| 2216 |
|
| 2217 | |
| 2218 | * flock_lock_inode_wait - Apply a FLOCK-style lock to a file
|
| 2219 | * @inode: inode of the file to apply to
|
| 2220 | * @fl: The lock to be applied
|
| 2221 | *
|
| 2222 | * Apply a FLOCK style lock request to an inode.
|
| 2223 |
|
| 2224 | static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl)
|
| 2225 | {
|
| 2226 | int error;
|
| 2227 | might_sleep();
|
| 2228 | for (;;) {
|
| 2229 | error = flock_lock_inode(inode, fl);
|
| 2230 | if (error != FILE_LOCK_DEFERRED)
|
| 2231 | break;
|
| 2232 | error = wait_event_interruptible(fl->c.flc_wait,
|
| 2233 | list_empty(&fl->c.flc_blocked_member));
|
| 2234 | if (error)
|
| 2235 | break;
|
| 2236 | }
|
| 2237 | locks_delete_block(fl);
|
| 2238 | return error;
|
| 2239 | }
|
| 2240 |
|
| 2241 | |
| 2242 | * locks_lock_inode_wait - Apply a lock to an inode
|
| 2243 | * @inode: inode of the file to apply to
|
| 2244 | * @fl: The lock to be applied
|
| 2245 | *
|
| 2246 | * Apply a POSIX or FLOCK style lock request to an inode.
|
| 2247 |
|
| 2248 | int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl)
|
| 2249 | {
|
| 2250 | int res = 0;
|
| 2251 | switch (fl->c.flc_flags & (FL_POSIX|FL_FLOCK)) {
|
| 2252 | case FL_POSIX:
|
| 2253 | res = posix_lock_inode_wait(inode, fl);
|
| 2254 | break;
|
| 2255 | case FL_FLOCK:
|
| 2256 | res = flock_lock_inode_wait(inode, fl);
|
| 2257 | break;
|
| 2258 | default:
|
| 2259 | BUG();
|
| 2260 | }
|
| 2261 | return res;
|
| 2262 | }
|
| 2263 | EXPORT_SYMBOL(locks_lock_inode_wait);
|
| 2264 |
|
| 2265 | |
| 2266 | * sys_flock: - flock() system call.
|
| 2267 | * @fd: the file descriptor to lock.
|
| 2268 | * @cmd: the type of lock to apply.
|
| 2269 | *
|
| 2270 | * Apply a %FL_FLOCK style lock to an open file descriptor.
|
| 2271 | * The @cmd can be one of:
|
| 2272 | *
|
| 2273 | * - %LOCK_SH -- a shared lock.
|
| 2274 | * - %LOCK_EX -- an exclusive lock.
|
| 2275 | * - %LOCK_UN -- remove an existing lock.
|
| 2276 | * - %LOCK_MAND -- a 'mandatory' flock. (DEPRECATED)
|
| 2277 | *
|
| 2278 | * %LOCK_MAND support has been removed from the kernel.
|
| 2279 |
|
| 2280 | SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
|
| 2281 | {
|
| 2282 | int can_sleep, error, type;
|
| 2283 | struct file_lock fl;
|
| 2284 |
|
| 2285 | |
| 2286 | * LOCK_MAND locks were broken for a long time in that they never
|
| 2287 | * conflicted with one another and didn't prevent any sort of open,
|
| 2288 | * read or write activity.
|
| 2289 | *
|
| 2290 | * Just ignore these requests now, to preserve legacy behavior, but
|
| 2291 | * throw a warning to let people know that they don't actually work.
|
| 2292 |
|
| 2293 | if (cmd & LOCK_MAND) {
|
| 2294 | pr_warn_once("%s(%d): Attempt to set a LOCK_MAND lock via flock(2). This support has been removed and the request ignored.\n", current->comm, current->pid);
|
| 2295 | return 0;
|
| 2296 | }
|
| 2297 |
|
| 2298 | type = flock_translate_cmd(cmd & ~LOCK_NB);
|
| 2299 | if (type < 0)
|
| 2300 | return type;
|
| 2301 |
|
| 2302 | CLASS(fd, f)(fd);
|
| 2303 | if (fd_empty(f))
|
| 2304 | return -EBADF;
|
| 2305 |
|
| 2306 | if (type != F_UNLCK && !(fd_file(f)->f_mode & (FMODE_READ | FMODE_WRITE)))
|
| 2307 | return -EBADF;
|
| 2308 |
|
| 2309 | flock_make_lock(fd_file(f), &fl, type);
|
| 2310 |
|
| 2311 | error = security_file_lock(fd_file(f), fl.c.flc_type);
|
| 2312 | if (error)
|
| 2313 | return error;
|
| 2314 |
|
| 2315 | can_sleep = !(cmd & LOCK_NB);
|
| 2316 | if (can_sleep)
|
| 2317 | fl.c.flc_flags |= FL_SLEEP;
|
| 2318 |
|
| 2319 | if (fd_file(f)->f_op->flock)
|
| 2320 | error = fd_file(f)->f_op->flock(fd_file(f),
|
| 2321 | (can_sleep) ? F_SETLKW : F_SETLK,
|
| 2322 | &fl);
|
| 2323 | else
|
| 2324 | error = locks_lock_file_wait(fd_file(f), &fl);
|
| 2325 |
|
| 2326 | locks_release_private(&fl);
|
| 2327 | return error;
|
| 2328 | }
|
| 2329 |
|
| 2330 | |
| 2331 | * vfs_test_lock - test file byte range lock
|
| 2332 | * @filp: The file to test lock for
|
| 2333 | * @fl: The byte-range in the file to test; also used to hold result
|
| 2334 | *
|
| 2335 | * On entry, @fl does not contain a lock, but identifies a range (fl_start, fl_end)
|
| 2336 | * in the file (c.flc_file), and an owner (c.flc_owner) for whom existing locks
|
| 2337 | * should be ignored. c.flc_type and c.flc_flags are ignored.
|
| 2338 | * Both fl_lmops and fl_ops in @fl must be NULL.
|
| 2339 | * Returns -ERRNO on failure. Indicates presence of conflicting lock by
|
| 2340 | * setting fl->fl_type to something other than F_UNLCK.
|
| 2341 | *
|
| 2342 | * If vfs_test_lock() does find a lock and return it, the caller must
|
| 2343 | * use locks_free_lock() or locks_release_private() on the returned lock.
|
| 2344 |
|
| 2345 | int vfs_test_lock(struct file *filp, struct file_lock *fl)
|
| 2346 | {
|
| 2347 | int error = 0;
|
| 2348 |
|
| 2349 | WARN_ON_ONCE(fl->fl_ops || fl->fl_lmops);
|
| 2350 | WARN_ON_ONCE(filp != fl->c.flc_file);
|
| 2351 | if (filp->f_op->lock)
|
| 2352 | error = filp->f_op->lock(filp, F_GETLK, fl);
|
| 2353 | else
|
| 2354 | posix_test_lock(filp, fl);
|
| 2355 |
|
| 2356 | |
| 2357 | * We don't expect FILE_LOCK_DEFERRED and callers cannot
|
| 2358 | * handle it.
|
| 2359 |
|
| 2360 | if (WARN_ON_ONCE(error == FILE_LOCK_DEFERRED))
|
| 2361 | error = -EIO;
|
| 2362 |
|
| 2363 | return error;
|
| 2364 | }
|
| 2365 | EXPORT_SYMBOL_GPL(vfs_test_lock);
|
| 2366 |
|
| 2367 | |
| 2368 | * locks_translate_pid - translate a file_lock's fl_pid number into a namespace
|
| 2369 | * @fl: The file_lock who's fl_pid should be translated
|
| 2370 | * @ns: The namespace into which the pid should be translated
|
| 2371 | *
|
| 2372 | * Used to translate a fl_pid into a namespace virtual pid number
|
| 2373 |
|
| 2374 | static pid_t locks_translate_pid(struct file_lock_core *fl, struct pid_namespace *ns)
|
| 2375 | {
|
| 2376 | pid_t vnr;
|
| 2377 | struct pid *pid;
|
| 2378 |
|
| 2379 | if (fl->flc_flags & FL_OFDLCK)
|
| 2380 | return -1;
|
| 2381 |
|
| 2382 |
|
| 2383 | if (fl->flc_pid <= 0)
|
| 2384 | return fl->flc_pid;
|
| 2385 |
|
| 2386 | |
| 2387 | * If the flock owner process is dead and its pid has been already
|
| 2388 | * freed, the translation below won't work, but we still want to show
|
| 2389 | * flock owner pid number in init pidns.
|
| 2390 |
|
| 2391 | if (ns == &init_pid_ns)
|
| 2392 | return (pid_t) fl->flc_pid;
|
| 2393 |
|
| 2394 | rcu_read_lock();
|
| 2395 | pid = find_pid_ns(fl->flc_pid, &init_pid_ns);
|
| 2396 | vnr = pid_nr_ns(pid, ns);
|
| 2397 | rcu_read_unlock();
|
| 2398 | return vnr;
|
| 2399 | }
|
| 2400 |
|
| 2401 | static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl)
|
| 2402 | {
|
| 2403 | flock->l_pid = locks_translate_pid(&fl->c, task_active_pid_ns(current));
|
| 2404 | #if BITS_PER_LONG == 32
|
| 2405 | |
| 2406 | * Make sure we can represent the posix lock via
|
| 2407 | * legacy 32bit flock.
|
| 2408 |
|
| 2409 | if (fl->fl_start > OFFT_OFFSET_MAX)
|
| 2410 | return -EOVERFLOW;
|
| 2411 | if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX)
|
| 2412 | return -EOVERFLOW;
|
| 2413 | #endif
|
| 2414 | flock->l_start = fl->fl_start;
|
| 2415 | flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
|
| 2416 | fl->fl_end - fl->fl_start + 1;
|
| 2417 | flock->l_whence = 0;
|
| 2418 | flock->l_type = fl->c.flc_type;
|
| 2419 | return 0;
|
| 2420 | }
|
| 2421 |
|
| 2422 | #if BITS_PER_LONG == 32
|
| 2423 | static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
|
| 2424 | {
|
| 2425 | flock->l_pid = locks_translate_pid(&fl->c, task_active_pid_ns(current));
|
| 2426 | flock->l_start = fl->fl_start;
|
| 2427 | flock->l_len = fl->fl_end == OFFSET_MAX ? 0 :
|
| 2428 | fl->fl_end - fl->fl_start + 1;
|
| 2429 | flock->l_whence = 0;
|
| 2430 | flock->l_type = fl->c.flc_type;
|
| 2431 | }
|
| 2432 | #endif
|
| 2433 |
|
| 2434 | |
| 2435 | * This implements the F_GETLK command of fcntl().
|
| 2436 |
|
| 2437 | int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock *flock)
|
| 2438 | {
|
| 2439 | struct file_lock *fl;
|
| 2440 | int error;
|
| 2441 |
|
| 2442 | fl = locks_alloc_lock();
|
| 2443 | if (fl == NULL)
|
| 2444 | return -ENOMEM;
|
| 2445 | error = -EINVAL;
|
| 2446 | if (cmd != F_OFD_GETLK && flock->l_type != F_RDLCK
|
| 2447 | && flock->l_type != F_WRLCK)
|
| 2448 | goto out;
|
| 2449 |
|
| 2450 | error = flock_to_posix_lock(filp, fl, flock);
|
| 2451 | if (error)
|
| 2452 | goto out;
|
| 2453 |
|
| 2454 | if (cmd == F_OFD_GETLK) {
|
| 2455 | error = -EINVAL;
|
| 2456 | if (flock->l_pid != 0)
|
| 2457 | goto out;
|
| 2458 |
|
| 2459 | fl->c.flc_flags |= FL_OFDLCK;
|
| 2460 | fl->c.flc_owner = filp;
|
| 2461 | }
|
| 2462 |
|
| 2463 | error = vfs_test_lock(filp, fl);
|
| 2464 | if (error)
|
| 2465 | goto out;
|
| 2466 |
|
| 2467 | flock->l_type = fl->c.flc_type;
|
| 2468 | if (fl->c.flc_type != F_UNLCK) {
|
| 2469 | error = posix_lock_to_flock(flock, fl);
|
| 2470 | if (error)
|
| 2471 | goto out;
|
| 2472 | }
|
| 2473 | out:
|
| 2474 | locks_free_lock(fl);
|
| 2475 | return error;
|
| 2476 | }
|
| 2477 |
|
| 2478 | |
| 2479 | * vfs_lock_file - file byte range lock
|
| 2480 | * @filp: The file to apply the lock to
|
| 2481 | * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.)
|
| 2482 | * @fl: The lock to be applied
|
| 2483 | * @conf: Place to return a copy of the conflicting lock, if found.
|
| 2484 | *
|
| 2485 | * A caller that doesn't care about the conflicting lock may pass NULL
|
| 2486 | * as the final argument.
|
| 2487 | *
|
| 2488 | * If the filesystem defines a private ->lock() method, then @conf will
|
| 2489 | * be left unchanged; so a caller that cares should initialize it to
|
| 2490 | * some acceptable default.
|
| 2491 | *
|
| 2492 | * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX
|
| 2493 | * locks, the ->lock() interface may return asynchronously, before the lock has
|
| 2494 | * been granted or denied by the underlying filesystem, if (and only if)
|
| 2495 | * lm_grant is set. Additionally FOP_ASYNC_LOCK in file_operations fop_flags
|
| 2496 | * need to be set.
|
| 2497 | *
|
| 2498 | * Callers expecting ->lock() to return asynchronously will only use F_SETLK,
|
| 2499 | * not F_SETLKW; they will set FL_SLEEP if (and only if) the request is for a
|
| 2500 | * blocking lock. When ->lock() does return asynchronously, it must return
|
| 2501 | * FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock request completes.
|
| 2502 | * If the request is for non-blocking lock the file system should return
|
| 2503 | * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine
|
| 2504 | * with the result. If the request timed out the callback routine will return a
|
| 2505 | * nonzero return code and the file system should release the lock. The file
|
| 2506 | * system is also responsible to keep a corresponding posix lock when it
|
| 2507 | * grants a lock so the VFS can find out which locks are locally held and do
|
| 2508 | * the correct lock cleanup when required.
|
| 2509 | * The underlying filesystem must not drop the kernel lock or call
|
| 2510 | * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED
|
| 2511 | * return code.
|
| 2512 |
|
| 2513 | int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf)
|
| 2514 | {
|
| 2515 | WARN_ON_ONCE(filp != fl->c.flc_file);
|
| 2516 | if (filp->f_op->lock)
|
| 2517 | return filp->f_op->lock(filp, cmd, fl);
|
| 2518 | else
|
| 2519 | return posix_lock_file(filp, fl, conf);
|
| 2520 | }
|
| 2521 | EXPORT_SYMBOL_GPL(vfs_lock_file);
|
| 2522 |
|
| 2523 | static int do_lock_file_wait(struct file *filp, unsigned int cmd,
|
| 2524 | struct file_lock *fl)
|
| 2525 | {
|
| 2526 | int error;
|
| 2527 |
|
| 2528 | error = security_file_lock(filp, fl->c.flc_type);
|
| 2529 | if (error)
|
| 2530 | return error;
|
| 2531 |
|
| 2532 | for (;;) {
|
| 2533 | error = vfs_lock_file(filp, cmd, fl, NULL);
|
| 2534 | if (error != FILE_LOCK_DEFERRED)
|
| 2535 | break;
|
| 2536 | error = wait_event_interruptible(fl->c.flc_wait,
|
| 2537 | list_empty(&fl->c.flc_blocked_member));
|
| 2538 | if (error)
|
| 2539 | break;
|
| 2540 | }
|
| 2541 | locks_delete_block(fl);
|
| 2542 |
|
| 2543 | return error;
|
| 2544 | }
|
| 2545 |
|
| 2546 |
|
| 2547 | static int
|
| 2548 | check_fmode_for_setlk(struct file_lock *fl)
|
| 2549 | {
|
| 2550 | switch (fl->c.flc_type) {
|
| 2551 | case F_RDLCK:
|
| 2552 | if (!(fl->c.flc_file->f_mode & FMODE_READ))
|
| 2553 | return -EBADF;
|
| 2554 | break;
|
| 2555 | case F_WRLCK:
|
| 2556 | if (!(fl->c.flc_file->f_mode & FMODE_WRITE))
|
| 2557 | return -EBADF;
|
| 2558 | }
|
| 2559 | return 0;
|
| 2560 | }
|
| 2561 |
|
| 2562 | |
| 2563 | * This implements both the F_SETLK and F_SETLKW commands of fcntl().
|
| 2564 |
|
| 2565 | int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
|
| 2566 | struct flock *flock)
|
| 2567 | {
|
| 2568 | struct file_lock *file_lock = locks_alloc_lock();
|
| 2569 | struct inode *inode = file_inode(filp);
|
| 2570 | struct file *f;
|
| 2571 | int error;
|
| 2572 |
|
| 2573 | if (file_lock == NULL)
|
| 2574 | return -ENOLCK;
|
| 2575 |
|
| 2576 | error = flock_to_posix_lock(filp, file_lock, flock);
|
| 2577 | if (error)
|
| 2578 | goto out;
|
| 2579 |
|
| 2580 | error = check_fmode_for_setlk(file_lock);
|
| 2581 | if (error)
|
| 2582 | goto out;
|
| 2583 |
|
| 2584 | |
| 2585 | * If the cmd is requesting file-private locks, then set the
|
| 2586 | * FL_OFDLCK flag and override the owner.
|
| 2587 |
|
| 2588 | switch (cmd) {
|
| 2589 | case F_OFD_SETLK:
|
| 2590 | error = -EINVAL;
|
| 2591 | if (flock->l_pid != 0)
|
| 2592 | goto out;
|
| 2593 |
|
| 2594 | cmd = F_SETLK;
|
| 2595 | file_lock->c.flc_flags |= FL_OFDLCK;
|
| 2596 | file_lock->c.flc_owner = filp;
|
| 2597 | break;
|
| 2598 | case F_OFD_SETLKW:
|
| 2599 | error = -EINVAL;
|
| 2600 | if (flock->l_pid != 0)
|
| 2601 | goto out;
|
| 2602 |
|
| 2603 | cmd = F_SETLKW;
|
| 2604 | file_lock->c.flc_flags |= FL_OFDLCK;
|
| 2605 | file_lock->c.flc_owner = filp;
|
| 2606 | fallthrough;
|
| 2607 | case F_SETLKW:
|
| 2608 | file_lock->c.flc_flags |= FL_SLEEP;
|
| 2609 | }
|
| 2610 |
|
| 2611 | error = do_lock_file_wait(filp, cmd, file_lock);
|
| 2612 |
|
| 2613 | |
| 2614 | * Detect close/fcntl races and recover by zapping all POSIX locks
|
| 2615 | * associated with this file and our files_struct, just like on
|
| 2616 | * filp_flush(). There is no need to do that when we're
|
| 2617 | * unlocking though, or for OFD locks.
|
| 2618 |
|
| 2619 | if (!error && file_lock->c.flc_type != F_UNLCK &&
|
| 2620 | !(file_lock->c.flc_flags & FL_OFDLCK)) {
|
| 2621 | struct files_struct *files = current->files;
|
| 2622 | |
| 2623 | * We need that spin_lock here - it prevents reordering between
|
| 2624 | * update of i_flctx->flc_posix and check for it done in
|
| 2625 | * close(). rcu_read_lock() wouldn't do.
|
| 2626 |
|
| 2627 | spin_lock(&files->file_lock);
|
| 2628 | f = files_lookup_fd_locked(files, fd);
|
| 2629 | spin_unlock(&files->file_lock);
|
| 2630 | if (f != filp) {
|
| 2631 | locks_remove_posix(filp, files);
|
| 2632 | error = -EBADF;
|
| 2633 | }
|
| 2634 | }
|
| 2635 | out:
|
| 2636 | trace_fcntl_setlk(inode, file_lock, error);
|
| 2637 | locks_free_lock(file_lock);
|
| 2638 | return error;
|
| 2639 | }
|
| 2640 |
|
| 2641 | #if BITS_PER_LONG == 32
|
| 2642 | |
| 2643 | * This implements the F_GETLK command of fcntl().
|
| 2644 |
|
| 2645 | int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 *flock)
|
| 2646 | {
|
| 2647 | struct file_lock *fl;
|
| 2648 | int error;
|
| 2649 |
|
| 2650 | fl = locks_alloc_lock();
|
| 2651 | if (fl == NULL)
|
| 2652 | return -ENOMEM;
|
| 2653 |
|
| 2654 | error = -EINVAL;
|
| 2655 | if (cmd != F_OFD_GETLK && flock->l_type != F_RDLCK
|
| 2656 | && flock->l_type != F_WRLCK)
|
| 2657 | goto out;
|
| 2658 |
|
| 2659 | error = flock64_to_posix_lock(filp, fl, flock);
|
| 2660 | if (error)
|
| 2661 | goto out;
|
| 2662 |
|
| 2663 | if (cmd == F_OFD_GETLK) {
|
| 2664 | error = -EINVAL;
|
| 2665 | if (flock->l_pid != 0)
|
| 2666 | goto out;
|
| 2667 |
|
| 2668 | fl->c.flc_flags |= FL_OFDLCK;
|
| 2669 | fl->c.flc_owner = filp;
|
| 2670 | }
|
| 2671 |
|
| 2672 | error = vfs_test_lock(filp, fl);
|
| 2673 | if (error)
|
| 2674 | goto out;
|
| 2675 |
|
| 2676 | flock->l_type = fl->c.flc_type;
|
| 2677 | if (fl->c.flc_type != F_UNLCK)
|
| 2678 | posix_lock_to_flock64(flock, fl);
|
| 2679 |
|
| 2680 | out:
|
| 2681 | locks_free_lock(fl);
|
| 2682 | return error;
|
| 2683 | }
|
| 2684 |
|
| 2685 | |
| 2686 | * This implements both the F_SETLK and F_SETLKW commands of fcntl().
|
| 2687 |
|
| 2688 | int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
|
| 2689 | struct flock64 *flock)
|
| 2690 | {
|
| 2691 | struct file_lock *file_lock = locks_alloc_lock();
|
| 2692 | struct file *f;
|
| 2693 | int error;
|
| 2694 |
|
| 2695 | if (file_lock == NULL)
|
| 2696 | return -ENOLCK;
|
| 2697 |
|
| 2698 | error = flock64_to_posix_lock(filp, file_lock, flock);
|
| 2699 | if (error)
|
| 2700 | goto out;
|
| 2701 |
|
| 2702 | error = check_fmode_for_setlk(file_lock);
|
| 2703 | if (error)
|
| 2704 | goto out;
|
| 2705 |
|
| 2706 | |
| 2707 | * If the cmd is requesting file-private locks, then set the
|
| 2708 | * FL_OFDLCK flag and override the owner.
|
| 2709 |
|
| 2710 | switch (cmd) {
|
| 2711 | case F_OFD_SETLK:
|
| 2712 | error = -EINVAL;
|
| 2713 | if (flock->l_pid != 0)
|
| 2714 | goto out;
|
| 2715 |
|
| 2716 | cmd = F_SETLK64;
|
| 2717 | file_lock->c.flc_flags |= FL_OFDLCK;
|
| 2718 | file_lock->c.flc_owner = filp;
|
| 2719 | break;
|
| 2720 | case F_OFD_SETLKW:
|
| 2721 | error = -EINVAL;
|
| 2722 | if (flock->l_pid != 0)
|
| 2723 | goto out;
|
| 2724 |
|
| 2725 | cmd = F_SETLKW64;
|
| 2726 | file_lock->c.flc_flags |= FL_OFDLCK;
|
| 2727 | file_lock->c.flc_owner = filp;
|
| 2728 | fallthrough;
|
| 2729 | case F_SETLKW64:
|
| 2730 | file_lock->c.flc_flags |= FL_SLEEP;
|
| 2731 | }
|
| 2732 |
|
| 2733 | error = do_lock_file_wait(filp, cmd, file_lock);
|
| 2734 |
|
| 2735 | |
| 2736 | * Detect close/fcntl races and recover by zapping all POSIX locks
|
| 2737 | * associated with this file and our files_struct, just like on
|
| 2738 | * filp_flush(). There is no need to do that when we're
|
| 2739 | * unlocking though, or for OFD locks.
|
| 2740 |
|
| 2741 | if (!error && file_lock->c.flc_type != F_UNLCK &&
|
| 2742 | !(file_lock->c.flc_flags & FL_OFDLCK)) {
|
| 2743 | struct files_struct *files = current->files;
|
| 2744 | |
| 2745 | * We need that spin_lock here - it prevents reordering between
|
| 2746 | * update of i_flctx->flc_posix and check for it done in
|
| 2747 | * close(). rcu_read_lock() wouldn't do.
|
| 2748 |
|
| 2749 | spin_lock(&files->file_lock);
|
| 2750 | f = files_lookup_fd_locked(files, fd);
|
| 2751 | spin_unlock(&files->file_lock);
|
| 2752 | if (f != filp) {
|
| 2753 | locks_remove_posix(filp, files);
|
| 2754 | error = -EBADF;
|
| 2755 | }
|
| 2756 | }
|
| 2757 | out:
|
| 2758 | locks_free_lock(file_lock);
|
| 2759 | return error;
|
| 2760 | }
|
| 2761 | #endif
|
| 2762 |
|
| 2763 | |
| 2764 | * This function is called when the file is being removed
|
| 2765 | * from the task's fd array. POSIX locks belonging to this task
|
| 2766 | * are deleted at this time.
|
| 2767 |
|
| 2768 | void locks_remove_posix(struct file *filp, fl_owner_t owner)
|
| 2769 | {
|
| 2770 | int error;
|
| 2771 | struct inode *inode = file_inode(filp);
|
| 2772 | struct file_lock lock;
|
| 2773 | struct file_lock_context *ctx;
|
| 2774 |
|
| 2775 | |
| 2776 | * If there are no locks held on this file, we don't need to call
|
| 2777 | * posix_lock_file(). Another process could be setting a lock on this
|
| 2778 | * file at the same time, but we wouldn't remove that lock anyway.
|
| 2779 |
|
| 2780 | ctx = locks_inode_context(inode);
|
| 2781 | if (!ctx || list_empty(&ctx->flc_posix))
|
| 2782 | return;
|
| 2783 |
|
| 2784 | locks_init_lock(&lock);
|
| 2785 | lock.c.flc_type = F_UNLCK;
|
| 2786 | lock.c.flc_flags = FL_POSIX | FL_CLOSE;
|
| 2787 | lock.fl_start = 0;
|
| 2788 | lock.fl_end = OFFSET_MAX;
|
| 2789 | lock.c.flc_owner = owner;
|
| 2790 | lock.c.flc_pid = current->tgid;
|
| 2791 | lock.c.flc_file = filp;
|
| 2792 | lock.fl_ops = NULL;
|
| 2793 | lock.fl_lmops = NULL;
|
| 2794 |
|
| 2795 | error = vfs_lock_file(filp, F_SETLK, &lock, NULL);
|
| 2796 |
|
| 2797 | if (lock.fl_ops && lock.fl_ops->fl_release_private)
|
| 2798 | lock.fl_ops->fl_release_private(&lock);
|
| 2799 | trace_locks_remove_posix(inode, &lock, error);
|
| 2800 | }
|
| 2801 | EXPORT_SYMBOL(locks_remove_posix);
|
| 2802 |
|
| 2803 |
|
| 2804 | static void
|
| 2805 | locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
|
| 2806 | {
|
| 2807 | struct file_lock fl;
|
| 2808 | struct inode *inode = file_inode(filp);
|
| 2809 |
|
| 2810 | if (list_empty(&flctx->flc_flock))
|
| 2811 | return;
|
| 2812 |
|
| 2813 | flock_make_lock(filp, &fl, F_UNLCK);
|
| 2814 | fl.c.flc_flags |= FL_CLOSE;
|
| 2815 |
|
| 2816 | if (filp->f_op->flock)
|
| 2817 | filp->f_op->flock(filp, F_SETLKW, &fl);
|
| 2818 | else
|
| 2819 | flock_lock_inode(inode, &fl);
|
| 2820 |
|
| 2821 | if (fl.fl_ops && fl.fl_ops->fl_release_private)
|
| 2822 | fl.fl_ops->fl_release_private(&fl);
|
| 2823 | }
|
| 2824 |
|
| 2825 |
|
| 2826 | static void
|
| 2827 | locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
|
| 2828 | {
|
| 2829 | struct file_lease *fl, *tmp;
|
| 2830 | LIST_HEAD(dispose);
|
| 2831 |
|
| 2832 | if (list_empty(&ctx->flc_lease))
|
| 2833 | return;
|
| 2834 |
|
| 2835 | percpu_down_read(&file_rwsem);
|
| 2836 | spin_lock(&ctx->flc_lock);
|
| 2837 | list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, c.flc_list)
|
| 2838 | if (filp == fl->c.flc_file)
|
| 2839 | lease_modify(fl, F_UNLCK, &dispose);
|
| 2840 | spin_unlock(&ctx->flc_lock);
|
| 2841 | percpu_up_read(&file_rwsem);
|
| 2842 |
|
| 2843 | lease_dispose_list(&dispose);
|
| 2844 | }
|
| 2845 |
|
| 2846 | |
| 2847 | * This function is called on the last close of an open file.
|
| 2848 |
|
| 2849 | void locks_remove_file(struct file *filp)
|
| 2850 | {
|
| 2851 | struct file_lock_context *ctx;
|
| 2852 |
|
| 2853 | ctx = locks_inode_context(file_inode(filp));
|
| 2854 | if (!ctx)
|
| 2855 | return;
|
| 2856 |
|
| 2857 |
|
| 2858 | locks_remove_posix(filp, filp);
|
| 2859 |
|
| 2860 |
|
| 2861 | locks_remove_flock(filp, ctx);
|
| 2862 |
|
| 2863 |
|
| 2864 | locks_remove_lease(filp, ctx);
|
| 2865 |
|
| 2866 | spin_lock(&ctx->flc_lock);
|
| 2867 | locks_check_ctx_file_list(filp, &ctx->flc_posix, "POSIX");
|
| 2868 | locks_check_ctx_file_list(filp, &ctx->flc_flock, "FLOCK");
|
| 2869 | locks_check_ctx_file_list(filp, &ctx->flc_lease, "LEASE");
|
| 2870 | spin_unlock(&ctx->flc_lock);
|
| 2871 | }
|
| 2872 |
|
| 2873 | |
| 2874 | * vfs_cancel_lock - file byte range unblock lock
|
| 2875 | * @filp: The file to apply the unblock to
|
| 2876 | * @fl: The lock to be unblocked
|
| 2877 | *
|
| 2878 | * Used by lock managers to cancel blocked requests
|
| 2879 |
|
| 2880 | int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
|
| 2881 | {
|
| 2882 | WARN_ON_ONCE(filp != fl->c.flc_file);
|
| 2883 | if (filp->f_op->lock)
|
| 2884 | return filp->f_op->lock(filp, F_CANCELLK, fl);
|
| 2885 | return 0;
|
| 2886 | }
|
| 2887 | EXPORT_SYMBOL_GPL(vfs_cancel_lock);
|
| 2888 |
|
| 2889 | |
| 2890 | * vfs_inode_has_locks - are any file locks held on @inode?
|
| 2891 | * @inode: inode to check for locks
|
| 2892 | *
|
| 2893 | * Return true if there are any FL_POSIX or FL_FLOCK locks currently
|
| 2894 | * set on @inode.
|
| 2895 |
|
| 2896 | bool vfs_inode_has_locks(struct inode *inode)
|
| 2897 | {
|
| 2898 | struct file_lock_context *ctx;
|
| 2899 | bool ret;
|
| 2900 |
|
| 2901 | ctx = locks_inode_context(inode);
|
| 2902 | if (!ctx)
|
| 2903 | return false;
|
| 2904 |
|
| 2905 | spin_lock(&ctx->flc_lock);
|
| 2906 | ret = !list_empty(&ctx->flc_posix) || !list_empty(&ctx->flc_flock);
|
| 2907 | spin_unlock(&ctx->flc_lock);
|
| 2908 | return ret;
|
| 2909 | }
|
| 2910 | EXPORT_SYMBOL_GPL(vfs_inode_has_locks);
|
| 2911 |
|
| 2912 | #ifdef CONFIG_PROC_FS
|
| 2913 | #include <linux/proc_fs.h>
|
| 2914 | #include <linux/seq_file.h>
|
| 2915 |
|
| 2916 | struct locks_iterator {
|
| 2917 | int li_cpu;
|
| 2918 | loff_t li_pos;
|
| 2919 | };
|
| 2920 |
|
| 2921 | static void lock_get_status(struct seq_file *f, struct file_lock_core *flc,
|
| 2922 | loff_t id, char *pfx, int repeat)
|
| 2923 | {
|
| 2924 | struct inode *inode = NULL;
|
| 2925 | unsigned int pid;
|
| 2926 | struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)->i_sb);
|
| 2927 | int type = flc->flc_type;
|
| 2928 | struct file_lock *fl = file_lock(flc);
|
| 2929 |
|
| 2930 | pid = locks_translate_pid(flc, proc_pidns);
|
| 2931 |
|
| 2932 | |
| 2933 | * If lock owner is dead (and pid is freed) or not visible in current
|
| 2934 | * pidns, zero is shown as a pid value. Check lock info from
|
| 2935 | * init_pid_ns to get saved lock pid value.
|
| 2936 |
|
| 2937 | if (flc->flc_file != NULL)
|
| 2938 | inode = file_inode(flc->flc_file);
|
| 2939 |
|
| 2940 | seq_printf(f, "%lld: ", id);
|
| 2941 |
|
| 2942 | if (repeat)
|
| 2943 | seq_printf(f, "%*s", repeat - 1 + (int)strlen(pfx), pfx);
|
| 2944 |
|
| 2945 | if (flc->flc_flags & FL_POSIX) {
|
| 2946 | if (flc->flc_flags & FL_ACCESS)
|
| 2947 | seq_puts(f, "ACCESS");
|
| 2948 | else if (flc->flc_flags & FL_OFDLCK)
|
| 2949 | seq_puts(f, "OFDLCK");
|
| 2950 | else
|
| 2951 | seq_puts(f, "POSIX ");
|
| 2952 |
|
| 2953 | seq_printf(f, " %s ",
|
| 2954 | (inode == NULL) ? "*NOINODE*" : "ADVISORY ");
|
| 2955 | } else if (flc->flc_flags & FL_FLOCK) {
|
| 2956 | seq_puts(f, "FLOCK ADVISORY ");
|
| 2957 | } else if (flc->flc_flags & (FL_LEASE|FL_DELEG|FL_LAYOUT)) {
|
| 2958 | struct file_lease *lease = file_lease(flc);
|
| 2959 |
|
| 2960 | type = target_leasetype(lease);
|
| 2961 |
|
| 2962 | if (flc->flc_flags & FL_DELEG)
|
| 2963 | seq_puts(f, "DELEG ");
|
| 2964 | else
|
| 2965 | seq_puts(f, "LEASE ");
|
| 2966 |
|
| 2967 | if (lease_breaking(lease))
|
| 2968 | seq_puts(f, "BREAKING ");
|
| 2969 | else if (flc->flc_file)
|
| 2970 | seq_puts(f, "ACTIVE ");
|
| 2971 | else
|
| 2972 | seq_puts(f, "BREAKER ");
|
| 2973 | } else {
|
| 2974 | seq_puts(f, "UNKNOWN UNKNOWN ");
|
| 2975 | }
|
| 2976 |
|
| 2977 | seq_printf(f, "%s ", (type == F_WRLCK) ? "WRITE" :
|
| 2978 | (type == F_RDLCK) ? "READ" : "UNLCK");
|
| 2979 | if (inode) {
|
| 2980 |
|
| 2981 | seq_printf(f, "%d %02x:%02x:%llu ", pid,
|
| 2982 | MAJOR(inode->i_sb->s_dev),
|
| 2983 | MINOR(inode->i_sb->s_dev), inode->i_ino);
|
| 2984 | } else {
|
| 2985 | seq_printf(f, "%d <none>:0 ", pid);
|
| 2986 | }
|
| 2987 | if (flc->flc_flags & FL_POSIX) {
|
| 2988 | if (fl->fl_end == OFFSET_MAX)
|
| 2989 | seq_printf(f, "%Ld EOF\n", fl->fl_start);
|
| 2990 | else
|
| 2991 | seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
|
| 2992 | } else {
|
| 2993 | seq_puts(f, "0 EOF\n");
|
| 2994 | }
|
| 2995 | }
|
| 2996 |
|
| 2997 | static struct file_lock_core *get_next_blocked_member(struct file_lock_core *node)
|
| 2998 | {
|
| 2999 | struct file_lock_core *tmp;
|
| 3000 |
|
| 3001 |
|
| 3002 | if (node == NULL || node->flc_blocker == NULL)
|
| 3003 | return NULL;
|
| 3004 |
|
| 3005 |
|
| 3006 | tmp = list_next_entry(node, flc_blocked_member);
|
| 3007 | if (list_entry_is_head(tmp, &node->flc_blocker->flc_blocked_requests,
|
| 3008 | flc_blocked_member)
|
| 3009 | || tmp == node) {
|
| 3010 | return NULL;
|
| 3011 | }
|
| 3012 |
|
| 3013 | return tmp;
|
| 3014 | }
|
| 3015 |
|
| 3016 | static int locks_show(struct seq_file *f, void *v)
|
| 3017 | {
|
| 3018 | struct locks_iterator *iter = f->private;
|
| 3019 | struct file_lock_core *cur, *tmp;
|
| 3020 | struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)->i_sb);
|
| 3021 | int level = 0;
|
| 3022 |
|
| 3023 | cur = hlist_entry(v, struct file_lock_core, flc_link);
|
| 3024 |
|
| 3025 | if (locks_translate_pid(cur, proc_pidns) == 0)
|
| 3026 | return 0;
|
| 3027 |
|
| 3028 | |
| 3029 | * is the left child of current node, the next silibing in flc_blocked_member is the
|
| 3030 | * right child, we can alse get the parent of current node from flc_blocker, so this
|
| 3031 | * question becomes traversal of a binary tree
|
| 3032 |
|
| 3033 | while (cur != NULL) {
|
| 3034 | if (level)
|
| 3035 | lock_get_status(f, cur, iter->li_pos, "-> ", level);
|
| 3036 | else
|
| 3037 | lock_get_status(f, cur, iter->li_pos, "", level);
|
| 3038 |
|
| 3039 | if (!list_empty(&cur->flc_blocked_requests)) {
|
| 3040 |
|
| 3041 | cur = list_first_entry_or_null(&cur->flc_blocked_requests,
|
| 3042 | struct file_lock_core,
|
| 3043 | flc_blocked_member);
|
| 3044 | level++;
|
| 3045 | } else {
|
| 3046 |
|
| 3047 | tmp = get_next_blocked_member(cur);
|
| 3048 |
|
| 3049 | while (tmp == NULL && cur->flc_blocker != NULL) {
|
| 3050 | cur = cur->flc_blocker;
|
| 3051 | level--;
|
| 3052 | tmp = get_next_blocked_member(cur);
|
| 3053 | }
|
| 3054 | cur = tmp;
|
| 3055 | }
|
| 3056 | }
|
| 3057 |
|
| 3058 | return 0;
|
| 3059 | }
|
| 3060 |
|
| 3061 | static void __show_fd_locks(struct seq_file *f,
|
| 3062 | struct list_head *head, int *id,
|
| 3063 | struct file *filp, struct files_struct *files)
|
| 3064 | {
|
| 3065 | struct file_lock_core *fl;
|
| 3066 |
|
| 3067 | list_for_each_entry(fl, head, flc_list) {
|
| 3068 |
|
| 3069 | if (filp != fl->flc_file)
|
| 3070 | continue;
|
| 3071 | if (fl->flc_owner != files && fl->flc_owner != filp)
|
| 3072 | continue;
|
| 3073 |
|
| 3074 | (*id)++;
|
| 3075 | seq_puts(f, "lock:\t");
|
| 3076 | lock_get_status(f, fl, *id, "", 0);
|
| 3077 | }
|
| 3078 | }
|
| 3079 |
|
| 3080 | void show_fd_locks(struct seq_file *f,
|
| 3081 | struct file *filp, struct files_struct *files)
|
| 3082 | {
|
| 3083 | struct inode *inode = file_inode(filp);
|
| 3084 | struct file_lock_context *ctx;
|
| 3085 | int id = 0;
|
| 3086 |
|
| 3087 | ctx = locks_inode_context(inode);
|
| 3088 | if (!ctx)
|
| 3089 | return;
|
| 3090 |
|
| 3091 | spin_lock(&ctx->flc_lock);
|
| 3092 | __show_fd_locks(f, &ctx->flc_flock, &id, filp, files);
|
| 3093 | __show_fd_locks(f, &ctx->flc_posix, &id, filp, files);
|
| 3094 | __show_fd_locks(f, &ctx->flc_lease, &id, filp, files);
|
| 3095 | spin_unlock(&ctx->flc_lock);
|
| 3096 | }
|
| 3097 |
|
| 3098 | static void *locks_start(struct seq_file *f, loff_t *pos)
|
| 3099 | __acquires(&blocked_lock_lock)
|
| 3100 | {
|
| 3101 | struct locks_iterator *iter = f->private;
|
| 3102 |
|
| 3103 | iter->li_pos = *pos + 1;
|
| 3104 | percpu_down_write(&file_rwsem);
|
| 3105 | spin_lock(&blocked_lock_lock);
|
| 3106 | return seq_hlist_start_percpu(&file_lock_list.hlist, &iter->li_cpu, *pos);
|
| 3107 | }
|
| 3108 |
|
| 3109 | static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
|
| 3110 | {
|
| 3111 | struct locks_iterator *iter = f->private;
|
| 3112 |
|
| 3113 | ++iter->li_pos;
|
| 3114 | return seq_hlist_next_percpu(v, &file_lock_list.hlist, &iter->li_cpu, pos);
|
| 3115 | }
|
| 3116 |
|
| 3117 | static void locks_stop(struct seq_file *f, void *v)
|
| 3118 | __releases(&blocked_lock_lock)
|
| 3119 | {
|
| 3120 | spin_unlock(&blocked_lock_lock);
|
| 3121 | percpu_up_write(&file_rwsem);
|
| 3122 | }
|
| 3123 |
|
| 3124 | static const struct seq_operations locks_seq_operations = {
|
| 3125 | .start = locks_start,
|
| 3126 | .next = locks_next,
|
| 3127 | .stop = locks_stop,
|
| 3128 | .show = locks_show,
|
| 3129 | };
|
| 3130 |
|
| 3131 | static int __init proc_locks_init(void)
|
| 3132 | {
|
| 3133 | proc_create_seq_private("locks", 0, NULL, &locks_seq_operations,
|
| 3134 | sizeof(struct locks_iterator), NULL);
|
| 3135 | return 0;
|
| 3136 | }
|
| 3137 | fs_initcall(proc_locks_init);
|
| 3138 | #endif
|
| 3139 |
|
| 3140 | static int __init filelock_init(void)
|
| 3141 | {
|
| 3142 | int i;
|
| 3143 |
|
| 3144 | flctx_cache = kmem_cache_create("file_lock_ctx",
|
| 3145 | sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL);
|
| 3146 |
|
| 3147 | filelock_cache = kmem_cache_create("file_lock_cache",
|
| 3148 | sizeof(struct file_lock), 0, SLAB_PANIC, NULL);
|
| 3149 |
|
| 3150 | filelease_cache = kmem_cache_create("file_lease_cache",
|
| 3151 | sizeof(struct file_lease), 0, SLAB_PANIC, NULL);
|
| 3152 |
|
| 3153 | for_each_possible_cpu(i) {
|
| 3154 | struct file_lock_list_struct *fll = per_cpu_ptr(&file_lock_list, i);
|
| 3155 |
|
| 3156 | spin_lock_init(&fll->lock);
|
| 3157 | INIT_HLIST_HEAD(&fll->hlist);
|
| 3158 | }
|
| 3159 |
|
| 3160 | lease_notifier_chain_init();
|
| 3161 | return 0;
|
| 3162 | }
|
| 3163 | core_initcall(filelock_init);
|