1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _LINUX_FILELOCK_H 3#define _LINUX_FILELOCK_H 4 5#include <linux/fs.h> 6 7#define FL_POSIX 1 8#define FL_FLOCK 2 9#define FL_DELEG 4 /* NFSv4 delegation */ 10#define FL_ACCESS 8 /* not trying to lock, just looking */ 11#define FL_EXISTS 16 /* when unlocking, test for existence */ 12#define FL_LEASE 32 /* lease held on this file */ 13#define FL_CLOSE 64 /* unlock on close */ 14#define FL_SLEEP 128 /* A blocking lock */ 15#define FL_DOWNGRADE_PENDING 256 /* Lease is being downgraded */ 16#define FL_UNLOCK_PENDING 512 /* Lease is being broken */ 17#define FL_OFDLCK 1024 /* lock is "owned" by struct file */ 18#define FL_LAYOUT 2048 /* outstanding pNFS layout */ 19#define FL_RECLAIM 4096 /* reclaiming from a reboot server */ 20 21#define FL_CLOSE_POSIX (FL_POSIX | FL_CLOSE) 22 23/* 24 * Special return value from posix_lock_file() and vfs_lock_file() for 25 * asynchronous locking. 26 */ 27#define FILE_LOCK_DEFERRED 1 28 29struct file_lock; 30struct file_lease; 31 32struct file_lock_operations { 33 void (*fl_copy_lock)(struct file_lock *, struct file_lock *); 34 void (*fl_release_private)(struct file_lock *); 35}; 36 37struct lock_manager_operations { 38 void *lm_mod_owner; 39 fl_owner_t (*lm_get_owner)(fl_owner_t); 40 void (*lm_put_owner)(fl_owner_t); 41 void (*lm_notify)(struct file_lock *); /* unblock callback */ 42 int (*lm_grant)(struct file_lock *, int); 43 bool (*lm_lock_expirable)(struct file_lock *cfl); 44 void (*lm_expire_lock)(void); 45}; 46 47struct lease_manager_operations { 48 bool (*lm_break)(struct file_lease *); 49 int (*lm_change)(struct file_lease *, int, struct list_head *); 50 void (*lm_setup)(struct file_lease *, void **); 51 bool (*lm_breaker_owns_lease)(struct file_lease *); 52}; 53 54struct lock_manager { 55 struct list_head list; 56 /* 57 * NFSv4 and up also want opens blocked during the grace period; 58 * NLM doesn't care: 59 */ 60 bool block_opens; 61}; 62 63struct net; 64void locks_start_grace(struct net *, struct lock_manager *); 65void locks_end_grace(struct lock_manager *); 66bool locks_in_grace(struct net *); 67bool opens_in_grace(struct net *); 68 69/* 70 * struct file_lock has a union that some filesystems use to track 71 * their own private info. The NFS side of things is defined here: 72 */ 73#include <linux/nfs_fs_i.h> 74 75/* 76 * struct file_lock represents a generic "file lock". It's used to represent 77 * POSIX byte range locks, BSD (flock) locks, and leases. It's important to 78 * note that the same struct is used to represent both a request for a lock and 79 * the lock itself, but the same object is never used for both. 80 * 81 * FIXME: should we create a separate "struct lock_request" to help distinguish 82 * these two uses? 83 * 84 * The varous i_flctx lists are ordered by: 85 * 86 * 1) lock owner 87 * 2) lock range start 88 * 3) lock range end 89 * 90 * Obviously, the last two criteria only matter for POSIX locks. 91 */ 92 93struct file_lock_core { 94 struct file_lock_core *flc_blocker; /* The lock that is blocking us */ 95 struct list_head flc_list; /* link into file_lock_context */ 96 struct hlist_node flc_link; /* node in global lists */ 97 struct list_head flc_blocked_requests; /* list of requests with 98 * ->fl_blocker pointing here 99 */ 100 struct list_head flc_blocked_member; /* node in 101 * ->fl_blocker->fl_blocked_requests 102 */ 103 fl_owner_t flc_owner; 104 unsigned int flc_flags; 105 unsigned char flc_type; 106 pid_t flc_pid; 107 int flc_link_cpu; /* what cpu's list is this on? */ 108 wait_queue_head_t flc_wait; 109 struct file *flc_file; 110}; 111 112struct file_lock { 113 struct file_lock_core c; 114 loff_t fl_start; 115 loff_t fl_end; 116 117 const struct file_lock_operations *fl_ops; /* Callbacks for filesystems */ 118 const struct lock_manager_operations *fl_lmops; /* Callbacks for lockmanagers */ 119 union { 120 struct nfs_lock_info nfs_fl; 121 struct nfs4_lock_info nfs4_fl; 122 struct { 123 struct list_head link; /* link in AFS vnode's pending_locks list */ 124 int state; /* state of grant or error if -ve */ 125 unsigned int debug_id; 126 } afs; 127 struct { 128 struct inode *inode; 129 } ceph; 130 } fl_u; 131} __randomize_layout; 132 133struct file_lease { 134 struct file_lock_core c; 135 struct fasync_struct * fl_fasync; /* for lease break notifications */ 136 /* for lease breaks: */ 137 unsigned long fl_break_time; 138 unsigned long fl_downgrade_time; 139 const struct lease_manager_operations *fl_lmops; /* Callbacks for lease managers */ 140} __randomize_layout; 141 142struct file_lock_context { 143 spinlock_t flc_lock; 144 struct list_head flc_flock; 145 struct list_head flc_posix; 146 struct list_head flc_lease; 147}; 148 149#ifdef CONFIG_FILE_LOCKING 150int fcntl_getlk(struct file *, unsigned int, struct flock *); 151int fcntl_setlk(unsigned int, struct file *, unsigned int, 152 struct flock *); 153 154#if BITS_PER_LONG == 32 155int fcntl_getlk64(struct file *, unsigned int, struct flock64 *); 156int fcntl_setlk64(unsigned int, struct file *, unsigned int, 157 struct flock64 *); 158#endif 159 160int fcntl_setlease(unsigned int fd, struct file *filp, int arg); 161int fcntl_getlease(struct file *filp); 162 163static inline bool lock_is_unlock(struct file_lock *fl) 164{ 165 return fl->c.flc_type == F_UNLCK; 166} 167 168static inline bool lock_is_read(struct file_lock *fl) 169{ 170 return fl->c.flc_type == F_RDLCK; 171} 172 173static inline bool lock_is_write(struct file_lock *fl) 174{ 175 return fl->c.flc_type == F_WRLCK; 176} 177 178static inline void locks_wake_up(struct file_lock *fl) 179{ 180 wake_up(&fl->c.flc_wait); 181} 182 183/* fs/locks.c */ 184void locks_free_lock_context(struct inode *inode); 185void locks_free_lock(struct file_lock *fl); 186void locks_init_lock(struct file_lock *); 187struct file_lock *locks_alloc_lock(void); 188void locks_copy_lock(struct file_lock *, struct file_lock *); 189void locks_copy_conflock(struct file_lock *, struct file_lock *); 190void locks_remove_posix(struct file *, fl_owner_t); 191void locks_remove_file(struct file *); 192void locks_release_private(struct file_lock *); 193void posix_test_lock(struct file *, struct file_lock *); 194int posix_lock_file(struct file *, struct file_lock *, struct file_lock *); 195int locks_delete_block(struct file_lock *); 196int vfs_test_lock(struct file *, struct file_lock *); 197int vfs_lock_file(struct file *, unsigned int, struct file_lock *, struct file_lock *); 198int vfs_cancel_lock(struct file *filp, struct file_lock *fl); 199bool vfs_inode_has_locks(struct inode *inode); 200int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl); 201 202void locks_init_lease(struct file_lease *); 203void locks_free_lease(struct file_lease *fl); 204struct file_lease *locks_alloc_lease(void); 205int __break_lease(struct inode *inode, unsigned int flags, unsigned int type); 206void lease_get_mtime(struct inode *, struct timespec64 *time); 207int generic_setlease(struct file *, int, struct file_lease **, void **priv); 208int kernel_setlease(struct file *, int, struct file_lease **, void **); 209int vfs_setlease(struct file *, int, struct file_lease **, void **); 210int lease_modify(struct file_lease *, int, struct list_head *); 211 212struct notifier_block; 213int lease_register_notifier(struct notifier_block *); 214void lease_unregister_notifier(struct notifier_block *); 215 216struct files_struct; 217void show_fd_locks(struct seq_file *f, 218 struct file *filp, struct files_struct *files); 219bool locks_owner_has_blockers(struct file_lock_context *flctx, 220 fl_owner_t owner); 221 222static inline struct file_lock_context * 223locks_inode_context(const struct inode *inode) 224{ 225 return smp_load_acquire(&inode->i_flctx); 226} 227 228#else /* !CONFIG_FILE_LOCKING */ 229static inline int fcntl_getlk(struct file *file, unsigned int cmd, 230 struct flock __user *user) 231{ 232 return -EINVAL; 233} 234 235static inline int fcntl_setlk(unsigned int fd, struct file *file, 236 unsigned int cmd, struct flock __user *user) 237{ 238 return -EACCES; 239} 240 241#if BITS_PER_LONG == 32 242static inline int fcntl_getlk64(struct file *file, unsigned int cmd, 243 struct flock64 *user) 244{ 245 return -EINVAL; 246} 247 248static inline int fcntl_setlk64(unsigned int fd, struct file *file, 249 unsigned int cmd, struct flock64 *user) 250{ 251 return -EACCES; 252} 253#endif 254static inline int fcntl_setlease(unsigned int fd, struct file *filp, int arg) 255{ 256 return -EINVAL; 257} 258 259static inline int fcntl_getlease(struct file *filp) 260{ 261 return F_UNLCK; 262} 263 264static inline bool lock_is_unlock(struct file_lock *fl) 265{ 266 return false; 267} 268 269static inline bool lock_is_read(struct file_lock *fl) 270{ 271 return false; 272} 273 274static inline bool lock_is_write(struct file_lock *fl) 275{ 276 return false; 277} 278 279static inline void locks_wake_up(struct file_lock *fl) 280{ 281} 282 283static inline void 284locks_free_lock_context(struct inode *inode) 285{ 286} 287 288static inline void locks_init_lock(struct file_lock *fl) 289{ 290 return; 291} 292 293static inline void locks_init_lease(struct file_lease *fl) 294{ 295 return; 296} 297 298static inline void locks_copy_conflock(struct file_lock *new, struct file_lock *fl) 299{ 300 return; 301} 302 303static inline void locks_copy_lock(struct file_lock *new, struct file_lock *fl) 304{ 305 return; 306} 307 308static inline void locks_remove_posix(struct file *filp, fl_owner_t owner) 309{ 310 return; 311} 312 313static inline void locks_remove_file(struct file *filp) 314{ 315 return; 316} 317 318static inline void posix_test_lock(struct file *filp, struct file_lock *fl) 319{ 320 return; 321} 322 323static inline int posix_lock_file(struct file *filp, struct file_lock *fl, 324 struct file_lock *conflock) 325{ 326 return -ENOLCK; 327} 328 329static inline int locks_delete_block(struct file_lock *waiter) 330{ 331 return -ENOENT; 332} 333 334static inline int vfs_test_lock(struct file *filp, struct file_lock *fl) 335{ 336 return 0; 337} 338 339static inline int vfs_lock_file(struct file *filp, unsigned int cmd, 340 struct file_lock *fl, struct file_lock *conf) 341{ 342 return -ENOLCK; 343} 344 345static inline int vfs_cancel_lock(struct file *filp, struct file_lock *fl) 346{ 347 return 0; 348} 349 350static inline bool vfs_inode_has_locks(struct inode *inode) 351{ 352 return false; 353} 354 355static inline int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl) 356{ 357 return -ENOLCK; 358} 359 360static inline int __break_lease(struct inode *inode, unsigned int mode, unsigned int type) 361{ 362 return 0; 363} 364 365static inline void lease_get_mtime(struct inode *inode, 366 struct timespec64 *time) 367{ 368 return; 369} 370 371static inline int generic_setlease(struct file *filp, int arg, 372 struct file_lease **flp, void **priv) 373{ 374 return -EINVAL; 375} 376 377static inline int kernel_setlease(struct file *filp, int arg, 378 struct file_lease **lease, void **priv) 379{ 380 return -EINVAL; 381} 382 383static inline int vfs_setlease(struct file *filp, int arg, 384 struct file_lease **lease, void **priv) 385{ 386 return -EINVAL; 387} 388 389static inline int lease_modify(struct file_lease *fl, int arg, 390 struct list_head *dispose) 391{ 392 return -EINVAL; 393} 394 395struct files_struct; 396static inline void show_fd_locks(struct seq_file *f, 397 struct file *filp, struct files_struct *files) {} 398static inline bool locks_owner_has_blockers(struct file_lock_context *flctx, 399 fl_owner_t owner) 400{ 401 return false; 402} 403 404static inline struct file_lock_context * 405locks_inode_context(const struct inode *inode) 406{ 407 return NULL; 408} 409 410#endif /* !CONFIG_FILE_LOCKING */ 411 412/* for walking lists of file_locks linked by fl_list */ 413#define for_each_file_lock(_fl, _head) list_for_each_entry(_fl, _head, c.flc_list) 414 415static inline int locks_lock_file_wait(struct file *filp, struct file_lock *fl) 416{ 417 return locks_lock_inode_wait(file_inode(filp), fl); 418} 419 420#ifdef CONFIG_FILE_LOCKING 421static inline int break_lease(struct inode *inode, unsigned int mode) 422{ 423 /* 424 * Since this check is lockless, we must ensure that any refcounts 425 * taken are done before checking i_flctx->flc_lease. Otherwise, we 426 * could end up racing with tasks trying to set a new lease on this 427 * file. 428 */ 429 smp_mb(); 430 if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease)) 431 return __break_lease(inode, mode, FL_LEASE); 432 return 0; 433} 434 435static inline int break_deleg(struct inode *inode, unsigned int mode) 436{ 437 /* 438 * Since this check is lockless, we must ensure that any refcounts 439 * taken are done before checking i_flctx->flc_lease. Otherwise, we 440 * could end up racing with tasks trying to set a new lease on this 441 * file. 442 */ 443 smp_mb(); 444 if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease)) 445 return __break_lease(inode, mode, FL_DELEG); 446 return 0; 447} 448 449static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode) 450{ 451 int ret; 452 453 ret = break_deleg(inode, O_WRONLY|O_NONBLOCK); 454 if (ret == -EWOULDBLOCK && delegated_inode) { 455 *delegated_inode = inode; 456 ihold(inode); 457 } 458 return ret; 459} 460 461static inline int break_deleg_wait(struct inode **delegated_inode) 462{ 463 int ret; 464 465 ret = break_deleg(*delegated_inode, O_WRONLY); 466 iput(*delegated_inode); 467 *delegated_inode = NULL; 468 return ret; 469} 470 471static inline int break_layout(struct inode *inode, bool wait) 472{ 473 smp_mb(); 474 if (inode->i_flctx && !list_empty_careful(&inode->i_flctx->flc_lease)) 475 return __break_lease(inode, 476 wait ? O_WRONLY : O_WRONLY | O_NONBLOCK, 477 FL_LAYOUT); 478 return 0; 479} 480 481#else /* !CONFIG_FILE_LOCKING */ 482static inline int break_lease(struct inode *inode, unsigned int mode) 483{ 484 return 0; 485} 486 487static inline int break_deleg(struct inode *inode, unsigned int mode) 488{ 489 return 0; 490} 491 492static inline int try_break_deleg(struct inode *inode, struct inode **delegated_inode) 493{ 494 return 0; 495} 496 497static inline int break_deleg_wait(struct inode **delegated_inode) 498{ 499 BUG(); 500 return 0; 501} 502 503static inline int break_layout(struct inode *inode, bool wait) 504{ 505 return 0; 506} 507 508#endif /* CONFIG_FILE_LOCKING */ 509 510#endif /* _LINUX_FILELOCK_H */ 511