Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * linux/fs/locks.c | |
4 | * | |
e9728cc7 BF |
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). | |
1da177e4 | 9 | * |
fd7732e0 N |
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 | * | |
1da177e4 LT |
50 | */ |
51 | ||
52 | #include <linux/capability.h> | |
53 | #include <linux/file.h> | |
9f3acc31 | 54 | #include <linux/fdtable.h> |
5970e15d | 55 | #include <linux/filelock.h> |
1da177e4 LT |
56 | #include <linux/fs.h> |
57 | #include <linux/init.h> | |
1da177e4 LT |
58 | #include <linux/security.h> |
59 | #include <linux/slab.h> | |
1da177e4 LT |
60 | #include <linux/syscalls.h> |
61 | #include <linux/time.h> | |
4fb3a538 | 62 | #include <linux/rcupdate.h> |
ab1f1611 | 63 | #include <linux/pid_namespace.h> |
48f74186 | 64 | #include <linux/hashtable.h> |
7012b02a | 65 | #include <linux/percpu.h> |
dd81faa8 | 66 | #include <linux/sysctl.h> |
1da177e4 | 67 | |
62af4f1f JL |
68 | #define CREATE_TRACE_POINTS |
69 | #include <trace/events/filelock.h> | |
70 | ||
7c0f6ba6 | 71 | #include <linux/uaccess.h> |
1da177e4 LT |
72 | |
73 | #define IS_POSIX(fl) (fl->fl_flags & FL_POSIX) | |
74 | #define IS_FLOCK(fl) (fl->fl_flags & FL_FLOCK) | |
11afe9f7 | 75 | #define IS_LEASE(fl) (fl->fl_flags & (FL_LEASE|FL_DELEG|FL_LAYOUT)) |
cff2fce5 | 76 | #define IS_OFDLCK(fl) (fl->fl_flags & FL_OFDLCK) |
9d5b86ac | 77 | #define IS_REMOTELCK(fl) (fl->fl_pid <= 0) |
1da177e4 | 78 | |
ab83fa4b BF |
79 | static bool lease_breaking(struct file_lock *fl) |
80 | { | |
778fc546 BF |
81 | return fl->fl_flags & (FL_UNLOCK_PENDING | FL_DOWNGRADE_PENDING); |
82 | } | |
83 | ||
84 | static int target_leasetype(struct file_lock *fl) | |
85 | { | |
86 | if (fl->fl_flags & FL_UNLOCK_PENDING) | |
87 | return F_UNLCK; | |
88 | if (fl->fl_flags & FL_DOWNGRADE_PENDING) | |
89 | return F_RDLCK; | |
90 | return fl->fl_type; | |
ab83fa4b BF |
91 | } |
92 | ||
dd81faa8 LC |
93 | static int leases_enable = 1; |
94 | static int lease_break_time = 45; | |
95 | ||
96 | #ifdef CONFIG_SYSCTL | |
97 | static struct ctl_table locks_sysctls[] = { | |
98 | { | |
99 | .procname = "leases-enable", | |
100 | .data = &leases_enable, | |
101 | .maxlen = sizeof(int), | |
102 | .mode = 0644, | |
103 | .proc_handler = proc_dointvec, | |
104 | }, | |
105 | #ifdef CONFIG_MMU | |
106 | { | |
107 | .procname = "lease-break-time", | |
108 | .data = &lease_break_time, | |
109 | .maxlen = sizeof(int), | |
110 | .mode = 0644, | |
111 | .proc_handler = proc_dointvec, | |
112 | }, | |
113 | #endif /* CONFIG_MMU */ | |
114 | {} | |
115 | }; | |
116 | ||
117 | static int __init init_fs_locks_sysctls(void) | |
118 | { | |
119 | register_sysctl_init("fs", locks_sysctls); | |
120 | return 0; | |
121 | } | |
122 | early_initcall(init_fs_locks_sysctls); | |
123 | #endif /* CONFIG_SYSCTL */ | |
1da177e4 | 124 | |
1c8c601a | 125 | /* |
7012b02a | 126 | * The global file_lock_list is only used for displaying /proc/locks, so we |
7c3f654d PZ |
127 | * keep a list on each CPU, with each list protected by its own spinlock. |
128 | * Global serialization is done using file_rwsem. | |
129 | * | |
130 | * Note that alterations to the list also require that the relevant flc_lock is | |
131 | * held. | |
1c8c601a | 132 | */ |
7c3f654d PZ |
133 | struct file_lock_list_struct { |
134 | spinlock_t lock; | |
135 | struct hlist_head hlist; | |
136 | }; | |
137 | static DEFINE_PER_CPU(struct file_lock_list_struct, file_lock_list); | |
aba37660 | 138 | DEFINE_STATIC_PERCPU_RWSEM(file_rwsem); |
88974691 | 139 | |
eb82dd39 | 140 | |
1c8c601a | 141 | /* |
48f74186 | 142 | * The blocked_hash is used to find POSIX lock loops for deadlock detection. |
7b2296af | 143 | * It is protected by blocked_lock_lock. |
48f74186 JL |
144 | * |
145 | * We hash locks by lockowner in order to optimize searching for the lock a | |
146 | * particular lockowner is waiting on. | |
147 | * | |
148 | * FIXME: make this value scale via some heuristic? We generally will want more | |
149 | * buckets when we have more lockowners holding locks, but that's a little | |
150 | * difficult to determine without knowing what the workload will look like. | |
1c8c601a | 151 | */ |
48f74186 JL |
152 | #define BLOCKED_HASH_BITS 7 |
153 | static DEFINE_HASHTABLE(blocked_hash, BLOCKED_HASH_BITS); | |
88974691 | 154 | |
1c8c601a | 155 | /* |
7b2296af JL |
156 | * This lock protects the blocked_hash. Generally, if you're accessing it, you |
157 | * want to be holding this lock. | |
1c8c601a | 158 | * |
ada5c1da N |
159 | * In addition, it also protects the fl->fl_blocked_requests list, and the |
160 | * fl->fl_blocker pointer for file_lock structures that are acting as lock | |
161 | * requests (in contrast to those that are acting as records of acquired locks). | |
1c8c601a JL |
162 | * |
163 | * Note that when we acquire this lock in order to change the above fields, | |
6109c850 | 164 | * we often hold the flc_lock as well. In certain cases, when reading the fields |
1c8c601a | 165 | * protected by this lock, we can skip acquiring it iff we already hold the |
6109c850 | 166 | * flc_lock. |
1c8c601a | 167 | */ |
7b2296af | 168 | static DEFINE_SPINLOCK(blocked_lock_lock); |
1da177e4 | 169 | |
68279f9c AD |
170 | static struct kmem_cache *flctx_cache __ro_after_init; |
171 | static struct kmem_cache *filelock_cache __ro_after_init; | |
1da177e4 | 172 | |
4a075e39 | 173 | static struct file_lock_context * |
5c1c669a | 174 | locks_get_lock_context(struct inode *inode, int type) |
4a075e39 | 175 | { |
128a3785 | 176 | struct file_lock_context *ctx; |
4a075e39 | 177 | |
128a3785 | 178 | /* paired with cmpxchg() below */ |
401a8b8f | 179 | ctx = locks_inode_context(inode); |
128a3785 | 180 | if (likely(ctx) || type == F_UNLCK) |
4a075e39 JL |
181 | goto out; |
182 | ||
128a3785 DV |
183 | ctx = kmem_cache_alloc(flctx_cache, GFP_KERNEL); |
184 | if (!ctx) | |
4a075e39 JL |
185 | goto out; |
186 | ||
128a3785 DV |
187 | spin_lock_init(&ctx->flc_lock); |
188 | INIT_LIST_HEAD(&ctx->flc_flock); | |
189 | INIT_LIST_HEAD(&ctx->flc_posix); | |
190 | INIT_LIST_HEAD(&ctx->flc_lease); | |
4a075e39 JL |
191 | |
192 | /* | |
193 | * Assign the pointer if it's not already assigned. If it is, then | |
194 | * free the context we just allocated. | |
195 | */ | |
128a3785 DV |
196 | if (cmpxchg(&inode->i_flctx, NULL, ctx)) { |
197 | kmem_cache_free(flctx_cache, ctx); | |
401a8b8f | 198 | ctx = locks_inode_context(inode); |
128a3785 | 199 | } |
4a075e39 | 200 | out: |
1890910f | 201 | trace_locks_get_lock_context(inode, type, ctx); |
128a3785 | 202 | return ctx; |
4a075e39 JL |
203 | } |
204 | ||
e24dadab JL |
205 | static void |
206 | locks_dump_ctx_list(struct list_head *list, char *list_type) | |
207 | { | |
208 | struct file_lock *fl; | |
209 | ||
210 | list_for_each_entry(fl, list, fl_list) { | |
211 | pr_warn("%s: fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n", list_type, fl->fl_owner, fl->fl_flags, fl->fl_type, fl->fl_pid); | |
212 | } | |
213 | } | |
214 | ||
215 | static void | |
216 | locks_check_ctx_lists(struct inode *inode) | |
217 | { | |
218 | struct file_lock_context *ctx = inode->i_flctx; | |
219 | ||
220 | if (unlikely(!list_empty(&ctx->flc_flock) || | |
221 | !list_empty(&ctx->flc_posix) || | |
222 | !list_empty(&ctx->flc_lease))) { | |
223 | pr_warn("Leaked locks on dev=0x%x:0x%x ino=0x%lx:\n", | |
224 | MAJOR(inode->i_sb->s_dev), MINOR(inode->i_sb->s_dev), | |
225 | inode->i_ino); | |
226 | locks_dump_ctx_list(&ctx->flc_flock, "FLOCK"); | |
227 | locks_dump_ctx_list(&ctx->flc_posix, "POSIX"); | |
228 | locks_dump_ctx_list(&ctx->flc_lease, "LEASE"); | |
229 | } | |
230 | } | |
231 | ||
3953704f BC |
232 | static void |
233 | locks_check_ctx_file_list(struct file *filp, struct list_head *list, | |
234 | char *list_type) | |
235 | { | |
236 | struct file_lock *fl; | |
c65454a9 | 237 | struct inode *inode = file_inode(filp); |
3953704f BC |
238 | |
239 | list_for_each_entry(fl, list, fl_list) | |
240 | if (fl->fl_file == filp) | |
241 | pr_warn("Leaked %s lock on dev=0x%x:0x%x ino=0x%lx " | |
242 | " fl_owner=%p fl_flags=0x%x fl_type=0x%x fl_pid=%u\n", | |
243 | list_type, MAJOR(inode->i_sb->s_dev), | |
244 | MINOR(inode->i_sb->s_dev), inode->i_ino, | |
245 | fl->fl_owner, fl->fl_flags, fl->fl_type, fl->fl_pid); | |
246 | } | |
247 | ||
4a075e39 | 248 | void |
f27a0fe0 | 249 | locks_free_lock_context(struct inode *inode) |
4a075e39 | 250 | { |
401a8b8f | 251 | struct file_lock_context *ctx = locks_inode_context(inode); |
f27a0fe0 | 252 | |
e24dadab JL |
253 | if (unlikely(ctx)) { |
254 | locks_check_ctx_lists(inode); | |
4a075e39 JL |
255 | kmem_cache_free(flctx_cache, ctx); |
256 | } | |
257 | } | |
258 | ||
ee19cc40 | 259 | static void locks_init_lock_heads(struct file_lock *fl) |
a51cb91d | 260 | { |
139ca04e | 261 | INIT_HLIST_NODE(&fl->fl_link); |
6dee60f6 | 262 | INIT_LIST_HEAD(&fl->fl_list); |
ada5c1da N |
263 | INIT_LIST_HEAD(&fl->fl_blocked_requests); |
264 | INIT_LIST_HEAD(&fl->fl_blocked_member); | |
ee19cc40 | 265 | init_waitqueue_head(&fl->fl_wait); |
a51cb91d MS |
266 | } |
267 | ||
1da177e4 | 268 | /* Allocate an empty lock structure. */ |
c5b1f0d9 | 269 | struct file_lock *locks_alloc_lock(void) |
1da177e4 | 270 | { |
ee19cc40 | 271 | struct file_lock *fl = kmem_cache_zalloc(filelock_cache, GFP_KERNEL); |
a51cb91d MS |
272 | |
273 | if (fl) | |
ee19cc40 | 274 | locks_init_lock_heads(fl); |
a51cb91d MS |
275 | |
276 | return fl; | |
1da177e4 | 277 | } |
c5b1f0d9 | 278 | EXPORT_SYMBOL_GPL(locks_alloc_lock); |
1da177e4 | 279 | |
a9e61e25 | 280 | void locks_release_private(struct file_lock *fl) |
47831f35 | 281 | { |
5926459e N |
282 | BUG_ON(waitqueue_active(&fl->fl_wait)); |
283 | BUG_ON(!list_empty(&fl->fl_list)); | |
284 | BUG_ON(!list_empty(&fl->fl_blocked_requests)); | |
285 | BUG_ON(!list_empty(&fl->fl_blocked_member)); | |
286 | BUG_ON(!hlist_unhashed(&fl->fl_link)); | |
287 | ||
47831f35 TM |
288 | if (fl->fl_ops) { |
289 | if (fl->fl_ops->fl_release_private) | |
290 | fl->fl_ops->fl_release_private(fl); | |
291 | fl->fl_ops = NULL; | |
292 | } | |
47831f35 | 293 | |
5c97d7b1 | 294 | if (fl->fl_lmops) { |
cae80b30 JL |
295 | if (fl->fl_lmops->lm_put_owner) { |
296 | fl->fl_lmops->lm_put_owner(fl->fl_owner); | |
297 | fl->fl_owner = NULL; | |
298 | } | |
5c97d7b1 KM |
299 | fl->fl_lmops = NULL; |
300 | } | |
47831f35 | 301 | } |
a9e61e25 | 302 | EXPORT_SYMBOL_GPL(locks_release_private); |
47831f35 | 303 | |
591502c5 DN |
304 | /** |
305 | * locks_owner_has_blockers - Check for blocking lock requests | |
306 | * @flctx: file lock context | |
307 | * @owner: lock owner | |
308 | * | |
309 | * Return values: | |
310 | * %true: @owner has at least one blocker | |
311 | * %false: @owner has no blockers | |
312 | */ | |
313 | bool locks_owner_has_blockers(struct file_lock_context *flctx, | |
314 | fl_owner_t owner) | |
315 | { | |
316 | struct file_lock *fl; | |
317 | ||
318 | spin_lock(&flctx->flc_lock); | |
319 | list_for_each_entry(fl, &flctx->flc_posix, fl_list) { | |
320 | if (fl->fl_owner != owner) | |
321 | continue; | |
322 | if (!list_empty(&fl->fl_blocked_requests)) { | |
323 | spin_unlock(&flctx->flc_lock); | |
324 | return true; | |
325 | } | |
326 | } | |
327 | spin_unlock(&flctx->flc_lock); | |
328 | return false; | |
329 | } | |
330 | EXPORT_SYMBOL_GPL(locks_owner_has_blockers); | |
331 | ||
1da177e4 | 332 | /* Free a lock which is not in use. */ |
05fa3135 | 333 | void locks_free_lock(struct file_lock *fl) |
1da177e4 | 334 | { |
47831f35 | 335 | locks_release_private(fl); |
1da177e4 LT |
336 | kmem_cache_free(filelock_cache, fl); |
337 | } | |
05fa3135 | 338 | EXPORT_SYMBOL(locks_free_lock); |
1da177e4 | 339 | |
ed9814d8 JL |
340 | static void |
341 | locks_dispose_list(struct list_head *dispose) | |
342 | { | |
343 | struct file_lock *fl; | |
344 | ||
345 | while (!list_empty(dispose)) { | |
6dee60f6 JL |
346 | fl = list_first_entry(dispose, struct file_lock, fl_list); |
347 | list_del_init(&fl->fl_list); | |
ed9814d8 JL |
348 | locks_free_lock(fl); |
349 | } | |
350 | } | |
351 | ||
1da177e4 LT |
352 | void locks_init_lock(struct file_lock *fl) |
353 | { | |
ee19cc40 MS |
354 | memset(fl, 0, sizeof(struct file_lock)); |
355 | locks_init_lock_heads(fl); | |
1da177e4 | 356 | } |
1da177e4 LT |
357 | EXPORT_SYMBOL(locks_init_lock); |
358 | ||
1da177e4 LT |
359 | /* |
360 | * Initialize a new lock from an existing file_lock structure. | |
361 | */ | |
3fe0fff1 | 362 | void locks_copy_conflock(struct file_lock *new, struct file_lock *fl) |
1da177e4 LT |
363 | { |
364 | new->fl_owner = fl->fl_owner; | |
365 | new->fl_pid = fl->fl_pid; | |
0996905f | 366 | new->fl_file = NULL; |
1da177e4 LT |
367 | new->fl_flags = fl->fl_flags; |
368 | new->fl_type = fl->fl_type; | |
369 | new->fl_start = fl->fl_start; | |
370 | new->fl_end = fl->fl_end; | |
f328296e | 371 | new->fl_lmops = fl->fl_lmops; |
0996905f | 372 | new->fl_ops = NULL; |
f328296e KM |
373 | |
374 | if (fl->fl_lmops) { | |
375 | if (fl->fl_lmops->lm_get_owner) | |
cae80b30 | 376 | fl->fl_lmops->lm_get_owner(fl->fl_owner); |
f328296e | 377 | } |
0996905f | 378 | } |
3fe0fff1 | 379 | EXPORT_SYMBOL(locks_copy_conflock); |
0996905f TM |
380 | |
381 | void locks_copy_lock(struct file_lock *new, struct file_lock *fl) | |
382 | { | |
566709bd JL |
383 | /* "new" must be a freshly-initialized lock */ |
384 | WARN_ON_ONCE(new->fl_ops); | |
0996905f | 385 | |
3fe0fff1 | 386 | locks_copy_conflock(new, fl); |
f328296e | 387 | |
0996905f | 388 | new->fl_file = fl->fl_file; |
1da177e4 | 389 | new->fl_ops = fl->fl_ops; |
47831f35 | 390 | |
f328296e KM |
391 | if (fl->fl_ops) { |
392 | if (fl->fl_ops->fl_copy_lock) | |
393 | fl->fl_ops->fl_copy_lock(new, fl); | |
394 | } | |
1da177e4 | 395 | } |
1da177e4 LT |
396 | EXPORT_SYMBOL(locks_copy_lock); |
397 | ||
5946c431 N |
398 | static void locks_move_blocks(struct file_lock *new, struct file_lock *fl) |
399 | { | |
400 | struct file_lock *f; | |
401 | ||
402 | /* | |
403 | * As ctx->flc_lock is held, new requests cannot be added to | |
404 | * ->fl_blocked_requests, so we don't need a lock to check if it | |
405 | * is empty. | |
406 | */ | |
407 | if (list_empty(&fl->fl_blocked_requests)) | |
408 | return; | |
409 | spin_lock(&blocked_lock_lock); | |
410 | list_splice_init(&fl->fl_blocked_requests, &new->fl_blocked_requests); | |
bf77ae4c | 411 | list_for_each_entry(f, &new->fl_blocked_requests, fl_blocked_member) |
5946c431 N |
412 | f->fl_blocker = new; |
413 | spin_unlock(&blocked_lock_lock); | |
414 | } | |
415 | ||
1da177e4 | 416 | static inline int flock_translate_cmd(int cmd) { |
1da177e4 LT |
417 | switch (cmd) { |
418 | case LOCK_SH: | |
419 | return F_RDLCK; | |
420 | case LOCK_EX: | |
421 | return F_WRLCK; | |
422 | case LOCK_UN: | |
423 | return F_UNLCK; | |
424 | } | |
425 | return -EINVAL; | |
426 | } | |
427 | ||
428 | /* Fill in a file_lock structure with an appropriate FLOCK lock. */ | |
4149be7b | 429 | static void flock_make_lock(struct file *filp, struct file_lock *fl, int type) |
1da177e4 | 430 | { |
4149be7b | 431 | locks_init_lock(fl); |
1da177e4 LT |
432 | |
433 | fl->fl_file = filp; | |
73a8f5f7 | 434 | fl->fl_owner = filp; |
1da177e4 LT |
435 | fl->fl_pid = current->tgid; |
436 | fl->fl_flags = FL_FLOCK; | |
437 | fl->fl_type = type; | |
438 | fl->fl_end = OFFSET_MAX; | |
1da177e4 LT |
439 | } |
440 | ||
ed5f17f6 | 441 | static int assign_type(struct file_lock *fl, int type) |
1da177e4 LT |
442 | { |
443 | switch (type) { | |
444 | case F_RDLCK: | |
445 | case F_WRLCK: | |
446 | case F_UNLCK: | |
447 | fl->fl_type = type; | |
448 | break; | |
449 | default: | |
450 | return -EINVAL; | |
451 | } | |
452 | return 0; | |
453 | } | |
454 | ||
ef12e72a BF |
455 | static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl, |
456 | struct flock64 *l) | |
1da177e4 | 457 | { |
1da177e4 | 458 | switch (l->l_whence) { |
f5579f8c | 459 | case SEEK_SET: |
ef12e72a | 460 | fl->fl_start = 0; |
1da177e4 | 461 | break; |
f5579f8c | 462 | case SEEK_CUR: |
ef12e72a | 463 | fl->fl_start = filp->f_pos; |
1da177e4 | 464 | break; |
f5579f8c | 465 | case SEEK_END: |
ef12e72a | 466 | fl->fl_start = i_size_read(file_inode(filp)); |
1da177e4 LT |
467 | break; |
468 | default: | |
469 | return -EINVAL; | |
470 | } | |
ef12e72a BF |
471 | if (l->l_start > OFFSET_MAX - fl->fl_start) |
472 | return -EOVERFLOW; | |
473 | fl->fl_start += l->l_start; | |
474 | if (fl->fl_start < 0) | |
475 | return -EINVAL; | |
1da177e4 LT |
476 | |
477 | /* POSIX-1996 leaves the case l->l_len < 0 undefined; | |
478 | POSIX-2001 defines it. */ | |
4c780a46 | 479 | if (l->l_len > 0) { |
ef12e72a BF |
480 | if (l->l_len - 1 > OFFSET_MAX - fl->fl_start) |
481 | return -EOVERFLOW; | |
16238415 | 482 | fl->fl_end = fl->fl_start + (l->l_len - 1); |
ef12e72a | 483 | |
4c780a46 | 484 | } else if (l->l_len < 0) { |
ef12e72a | 485 | if (fl->fl_start + l->l_len < 0) |
4c780a46 | 486 | return -EINVAL; |
ef12e72a BF |
487 | fl->fl_end = fl->fl_start - 1; |
488 | fl->fl_start += l->l_len; | |
489 | } else | |
490 | fl->fl_end = OFFSET_MAX; | |
491 | ||
1da177e4 LT |
492 | fl->fl_owner = current->files; |
493 | fl->fl_pid = current->tgid; | |
494 | fl->fl_file = filp; | |
495 | fl->fl_flags = FL_POSIX; | |
496 | fl->fl_ops = NULL; | |
497 | fl->fl_lmops = NULL; | |
498 | ||
499 | return assign_type(fl, l->l_type); | |
500 | } | |
501 | ||
ef12e72a BF |
502 | /* Verify a "struct flock" and copy it to a "struct file_lock" as a POSIX |
503 | * style lock. | |
504 | */ | |
505 | static int flock_to_posix_lock(struct file *filp, struct file_lock *fl, | |
506 | struct flock *l) | |
1da177e4 | 507 | { |
ef12e72a BF |
508 | struct flock64 ll = { |
509 | .l_type = l->l_type, | |
510 | .l_whence = l->l_whence, | |
511 | .l_start = l->l_start, | |
512 | .l_len = l->l_len, | |
513 | }; | |
514 | ||
515 | return flock64_to_posix_lock(filp, fl, &ll); | |
1da177e4 | 516 | } |
1da177e4 LT |
517 | |
518 | /* default lease lock manager operations */ | |
4d01b7f5 JL |
519 | static bool |
520 | lease_break_callback(struct file_lock *fl) | |
1da177e4 LT |
521 | { |
522 | kill_fasync(&fl->fl_fasync, SIGIO, POLL_MSG); | |
4d01b7f5 | 523 | return false; |
1da177e4 LT |
524 | } |
525 | ||
1c7dd2ff JL |
526 | static void |
527 | lease_setup(struct file_lock *fl, void **priv) | |
528 | { | |
529 | struct file *filp = fl->fl_file; | |
530 | struct fasync_struct *fa = *priv; | |
531 | ||
532 | /* | |
533 | * fasync_insert_entry() returns the old entry if any. If there was no | |
534 | * old entry, then it used "priv" and inserted it into the fasync list. | |
535 | * Clear the pointer to indicate that it shouldn't be freed. | |
536 | */ | |
537 | if (!fasync_insert_entry(fa->fa_fd, filp, &fl->fl_fasync, fa)) | |
538 | *priv = NULL; | |
539 | ||
01919134 | 540 | __f_setown(filp, task_pid(current), PIDTYPE_TGID, 0); |
1c7dd2ff JL |
541 | } |
542 | ||
7b021967 | 543 | static const struct lock_manager_operations lease_manager_ops = { |
8fb47a4f | 544 | .lm_break = lease_break_callback, |
8fb47a4f | 545 | .lm_change = lease_modify, |
1c7dd2ff | 546 | .lm_setup = lease_setup, |
1da177e4 LT |
547 | }; |
548 | ||
549 | /* | |
550 | * Initialize a lease, use the default lock manager operations | |
551 | */ | |
ed5f17f6 | 552 | static int lease_init(struct file *filp, int type, struct file_lock *fl) |
447a5647 | 553 | { |
75dff55a TM |
554 | if (assign_type(fl, type) != 0) |
555 | return -EINVAL; | |
556 | ||
7ca76311 | 557 | fl->fl_owner = filp; |
1da177e4 LT |
558 | fl->fl_pid = current->tgid; |
559 | ||
560 | fl->fl_file = filp; | |
561 | fl->fl_flags = FL_LEASE; | |
1da177e4 LT |
562 | fl->fl_start = 0; |
563 | fl->fl_end = OFFSET_MAX; | |
564 | fl->fl_ops = NULL; | |
565 | fl->fl_lmops = &lease_manager_ops; | |
566 | return 0; | |
567 | } | |
568 | ||
569 | /* Allocate a file_lock initialised to this type of lease */ | |
ed5f17f6 | 570 | static struct file_lock *lease_alloc(struct file *filp, int type) |
1da177e4 LT |
571 | { |
572 | struct file_lock *fl = locks_alloc_lock(); | |
75dff55a | 573 | int error = -ENOMEM; |
1da177e4 LT |
574 | |
575 | if (fl == NULL) | |
e32b8ee2 | 576 | return ERR_PTR(error); |
1da177e4 LT |
577 | |
578 | error = lease_init(filp, type, fl); | |
75dff55a TM |
579 | if (error) { |
580 | locks_free_lock(fl); | |
e32b8ee2 | 581 | return ERR_PTR(error); |
75dff55a | 582 | } |
e32b8ee2 | 583 | return fl; |
1da177e4 LT |
584 | } |
585 | ||
586 | /* Check if two locks overlap each other. | |
587 | */ | |
588 | static inline int locks_overlap(struct file_lock *fl1, struct file_lock *fl2) | |
589 | { | |
590 | return ((fl1->fl_end >= fl2->fl_start) && | |
591 | (fl2->fl_end >= fl1->fl_start)); | |
592 | } | |
593 | ||
594 | /* | |
595 | * Check whether two locks have the same owner. | |
596 | */ | |
33443c42 | 597 | static int posix_same_owner(struct file_lock *fl1, struct file_lock *fl2) |
1da177e4 | 598 | { |
1da177e4 LT |
599 | return fl1->fl_owner == fl2->fl_owner; |
600 | } | |
601 | ||
6109c850 | 602 | /* Must be called with the flc_lock held! */ |
6ca10ed8 | 603 | static void locks_insert_global_locks(struct file_lock *fl) |
88974691 | 604 | { |
7c3f654d PZ |
605 | struct file_lock_list_struct *fll = this_cpu_ptr(&file_lock_list); |
606 | ||
aba37660 PZ |
607 | percpu_rwsem_assert_held(&file_rwsem); |
608 | ||
7c3f654d | 609 | spin_lock(&fll->lock); |
7012b02a | 610 | fl->fl_link_cpu = smp_processor_id(); |
7c3f654d PZ |
611 | hlist_add_head(&fl->fl_link, &fll->hlist); |
612 | spin_unlock(&fll->lock); | |
88974691 JL |
613 | } |
614 | ||
6109c850 | 615 | /* Must be called with the flc_lock held! */ |
6ca10ed8 | 616 | static void locks_delete_global_locks(struct file_lock *fl) |
88974691 | 617 | { |
7c3f654d PZ |
618 | struct file_lock_list_struct *fll; |
619 | ||
aba37660 PZ |
620 | percpu_rwsem_assert_held(&file_rwsem); |
621 | ||
7012b02a JL |
622 | /* |
623 | * Avoid taking lock if already unhashed. This is safe since this check | |
6109c850 | 624 | * is done while holding the flc_lock, and new insertions into the list |
7012b02a JL |
625 | * also require that it be held. |
626 | */ | |
627 | if (hlist_unhashed(&fl->fl_link)) | |
628 | return; | |
7c3f654d PZ |
629 | |
630 | fll = per_cpu_ptr(&file_lock_list, fl->fl_link_cpu); | |
631 | spin_lock(&fll->lock); | |
139ca04e | 632 | hlist_del_init(&fl->fl_link); |
7c3f654d | 633 | spin_unlock(&fll->lock); |
88974691 JL |
634 | } |
635 | ||
3999e493 JL |
636 | static unsigned long |
637 | posix_owner_key(struct file_lock *fl) | |
638 | { | |
3999e493 JL |
639 | return (unsigned long)fl->fl_owner; |
640 | } | |
641 | ||
6ca10ed8 | 642 | static void locks_insert_global_blocked(struct file_lock *waiter) |
88974691 | 643 | { |
663d5af7 DW |
644 | lockdep_assert_held(&blocked_lock_lock); |
645 | ||
3999e493 | 646 | hash_add(blocked_hash, &waiter->fl_link, posix_owner_key(waiter)); |
88974691 JL |
647 | } |
648 | ||
6ca10ed8 | 649 | static void locks_delete_global_blocked(struct file_lock *waiter) |
88974691 | 650 | { |
663d5af7 DW |
651 | lockdep_assert_held(&blocked_lock_lock); |
652 | ||
48f74186 | 653 | hash_del(&waiter->fl_link); |
88974691 JL |
654 | } |
655 | ||
1da177e4 LT |
656 | /* Remove waiter from blocker's block list. |
657 | * When blocker ends up pointing to itself then the list is empty. | |
1c8c601a | 658 | * |
7b2296af | 659 | * Must be called with blocked_lock_lock held. |
1da177e4 | 660 | */ |
33443c42 | 661 | static void __locks_delete_block(struct file_lock *waiter) |
1da177e4 | 662 | { |
88974691 | 663 | locks_delete_global_blocked(waiter); |
ada5c1da | 664 | list_del_init(&waiter->fl_blocked_member); |
1da177e4 LT |
665 | } |
666 | ||
ad6bbd8b N |
667 | static void __locks_wake_up_blocks(struct file_lock *blocker) |
668 | { | |
669 | while (!list_empty(&blocker->fl_blocked_requests)) { | |
670 | struct file_lock *waiter; | |
671 | ||
672 | waiter = list_first_entry(&blocker->fl_blocked_requests, | |
673 | struct file_lock, fl_blocked_member); | |
674 | __locks_delete_block(waiter); | |
675 | if (waiter->fl_lmops && waiter->fl_lmops->lm_notify) | |
676 | waiter->fl_lmops->lm_notify(waiter); | |
677 | else | |
678 | wake_up(&waiter->fl_wait); | |
dcf23ac3 LT |
679 | |
680 | /* | |
681 | * The setting of fl_blocker to NULL marks the "done" | |
682 | * point in deleting a block. Paired with acquire at the top | |
683 | * of locks_delete_block(). | |
684 | */ | |
685 | smp_store_release(&waiter->fl_blocker, NULL); | |
ad6bbd8b N |
686 | } |
687 | } | |
688 | ||
cb03f94f | 689 | /** |
529adfe8 | 690 | * locks_delete_block - stop waiting for a file lock |
cb03f94f N |
691 | * @waiter: the lock which was waiting |
692 | * | |
693 | * lockd/nfsd need to disconnect the lock while working on it. | |
694 | */ | |
695 | int locks_delete_block(struct file_lock *waiter) | |
1da177e4 | 696 | { |
cb03f94f N |
697 | int status = -ENOENT; |
698 | ||
dcf23ac3 LT |
699 | /* |
700 | * If fl_blocker is NULL, it won't be set again as this thread "owns" | |
701 | * the lock and is the only one that might try to claim the lock. | |
702 | * | |
703 | * We use acquire/release to manage fl_blocker so that we can | |
704 | * optimize away taking the blocked_lock_lock in many cases. | |
705 | * | |
706 | * The smp_load_acquire guarantees two things: | |
707 | * | |
708 | * 1/ that fl_blocked_requests can be tested locklessly. If something | |
709 | * was recently added to that list it must have been in a locked region | |
710 | * *before* the locked region when fl_blocker was set to NULL. | |
711 | * | |
712 | * 2/ that no other thread is accessing 'waiter', so it is safe to free | |
713 | * it. __locks_wake_up_blocks is careful not to touch waiter after | |
714 | * fl_blocker is released. | |
715 | * | |
716 | * If a lockless check of fl_blocker shows it to be NULL, we know that | |
717 | * no new locks can be inserted into its fl_blocked_requests list, and | |
718 | * can avoid doing anything further if the list is empty. | |
719 | */ | |
720 | if (!smp_load_acquire(&waiter->fl_blocker) && | |
721 | list_empty(&waiter->fl_blocked_requests)) | |
722 | return status; | |
723 | ||
7b2296af | 724 | spin_lock(&blocked_lock_lock); |
cb03f94f N |
725 | if (waiter->fl_blocker) |
726 | status = 0; | |
5946c431 | 727 | __locks_wake_up_blocks(waiter); |
1da177e4 | 728 | __locks_delete_block(waiter); |
dcf23ac3 LT |
729 | |
730 | /* | |
731 | * The setting of fl_blocker to NULL marks the "done" point in deleting | |
732 | * a block. Paired with acquire at the top of this function. | |
733 | */ | |
734 | smp_store_release(&waiter->fl_blocker, NULL); | |
7b2296af | 735 | spin_unlock(&blocked_lock_lock); |
cb03f94f | 736 | return status; |
1da177e4 | 737 | } |
cb03f94f | 738 | EXPORT_SYMBOL(locks_delete_block); |
1da177e4 LT |
739 | |
740 | /* Insert waiter into blocker's block list. | |
741 | * We use a circular list so that processes can be easily woken up in | |
742 | * the order they blocked. The documentation doesn't require this but | |
743 | * it seems like the reasonable thing to do. | |
1c8c601a | 744 | * |
6109c850 | 745 | * Must be called with both the flc_lock and blocked_lock_lock held. The |
ada5c1da N |
746 | * fl_blocked_requests list itself is protected by the blocked_lock_lock, |
747 | * but by ensuring that the flc_lock is also held on insertions we can avoid | |
748 | * taking the blocked_lock_lock in some cases when we see that the | |
749 | * fl_blocked_requests list is empty. | |
fd7732e0 N |
750 | * |
751 | * Rather than just adding to the list, we check for conflicts with any existing | |
752 | * waiters, and add beneath any waiter that blocks the new waiter. | |
753 | * Thus wakeups don't happen until needed. | |
1da177e4 | 754 | */ |
1c8c601a | 755 | static void __locks_insert_block(struct file_lock *blocker, |
fd7732e0 N |
756 | struct file_lock *waiter, |
757 | bool conflict(struct file_lock *, | |
758 | struct file_lock *)) | |
1da177e4 | 759 | { |
fd7732e0 | 760 | struct file_lock *fl; |
ada5c1da | 761 | BUG_ON(!list_empty(&waiter->fl_blocked_member)); |
fd7732e0 N |
762 | |
763 | new_blocker: | |
764 | list_for_each_entry(fl, &blocker->fl_blocked_requests, fl_blocked_member) | |
765 | if (conflict(fl, waiter)) { | |
766 | blocker = fl; | |
767 | goto new_blocker; | |
768 | } | |
ada5c1da N |
769 | waiter->fl_blocker = blocker; |
770 | list_add_tail(&waiter->fl_blocked_member, &blocker->fl_blocked_requests); | |
cff2fce5 | 771 | if (IS_POSIX(blocker) && !IS_OFDLCK(blocker)) |
1c8c601a | 772 | locks_insert_global_blocked(waiter); |
5946c431 N |
773 | |
774 | /* The requests in waiter->fl_blocked are known to conflict with | |
775 | * waiter, but might not conflict with blocker, or the requests | |
776 | * and lock which block it. So they all need to be woken. | |
777 | */ | |
778 | __locks_wake_up_blocks(waiter); | |
1c8c601a JL |
779 | } |
780 | ||
6109c850 | 781 | /* Must be called with flc_lock held. */ |
1c8c601a | 782 | static void locks_insert_block(struct file_lock *blocker, |
fd7732e0 N |
783 | struct file_lock *waiter, |
784 | bool conflict(struct file_lock *, | |
785 | struct file_lock *)) | |
1c8c601a | 786 | { |
7b2296af | 787 | spin_lock(&blocked_lock_lock); |
fd7732e0 | 788 | __locks_insert_block(blocker, waiter, conflict); |
7b2296af | 789 | spin_unlock(&blocked_lock_lock); |
1da177e4 LT |
790 | } |
791 | ||
1cb36012 JL |
792 | /* |
793 | * Wake up processes blocked waiting for blocker. | |
794 | * | |
6109c850 | 795 | * Must be called with the inode->flc_lock held! |
1da177e4 LT |
796 | */ |
797 | static void locks_wake_up_blocks(struct file_lock *blocker) | |
798 | { | |
4e8c765d JL |
799 | /* |
800 | * Avoid taking global lock if list is empty. This is safe since new | |
6109c850 | 801 | * blocked requests are only added to the list under the flc_lock, and |
ada5c1da N |
802 | * the flc_lock is always held here. Note that removal from the |
803 | * fl_blocked_requests list does not require the flc_lock, so we must | |
804 | * recheck list_empty() after acquiring the blocked_lock_lock. | |
4e8c765d | 805 | */ |
ada5c1da | 806 | if (list_empty(&blocker->fl_blocked_requests)) |
4e8c765d JL |
807 | return; |
808 | ||
7b2296af | 809 | spin_lock(&blocked_lock_lock); |
ad6bbd8b | 810 | __locks_wake_up_blocks(blocker); |
7b2296af | 811 | spin_unlock(&blocked_lock_lock); |
1da177e4 LT |
812 | } |
813 | ||
5263e31e | 814 | static void |
e084c1bd | 815 | locks_insert_lock_ctx(struct file_lock *fl, struct list_head *before) |
5263e31e | 816 | { |
5263e31e JL |
817 | list_add_tail(&fl->fl_list, before); |
818 | locks_insert_global_locks(fl); | |
819 | } | |
820 | ||
8634b51f | 821 | static void |
e084c1bd | 822 | locks_unlink_lock_ctx(struct file_lock *fl) |
1da177e4 | 823 | { |
88974691 | 824 | locks_delete_global_locks(fl); |
8634b51f | 825 | list_del_init(&fl->fl_list); |
1da177e4 | 826 | locks_wake_up_blocks(fl); |
24cbe784 JL |
827 | } |
828 | ||
8634b51f | 829 | static void |
e084c1bd | 830 | locks_delete_lock_ctx(struct file_lock *fl, struct list_head *dispose) |
24cbe784 | 831 | { |
e084c1bd | 832 | locks_unlink_lock_ctx(fl); |
ed9814d8 | 833 | if (dispose) |
6dee60f6 | 834 | list_add(&fl->fl_list, dispose); |
ed9814d8 JL |
835 | else |
836 | locks_free_lock(fl); | |
1da177e4 LT |
837 | } |
838 | ||
839 | /* Determine if lock sys_fl blocks lock caller_fl. Common functionality | |
840 | * checks for shared/exclusive status of overlapping locks. | |
841 | */ | |
c0e15908 N |
842 | static bool locks_conflict(struct file_lock *caller_fl, |
843 | struct file_lock *sys_fl) | |
1da177e4 LT |
844 | { |
845 | if (sys_fl->fl_type == F_WRLCK) | |
c0e15908 | 846 | return true; |
1da177e4 | 847 | if (caller_fl->fl_type == F_WRLCK) |
c0e15908 N |
848 | return true; |
849 | return false; | |
1da177e4 LT |
850 | } |
851 | ||
852 | /* Determine if lock sys_fl blocks lock caller_fl. POSIX specific | |
853 | * checking before calling the locks_conflict(). | |
854 | */ | |
c0e15908 N |
855 | static bool posix_locks_conflict(struct file_lock *caller_fl, |
856 | struct file_lock *sys_fl) | |
1da177e4 LT |
857 | { |
858 | /* POSIX locks owned by the same process do not conflict with | |
859 | * each other. | |
860 | */ | |
9b8c8695 | 861 | if (posix_same_owner(caller_fl, sys_fl)) |
c0e15908 | 862 | return false; |
1da177e4 LT |
863 | |
864 | /* Check whether they overlap */ | |
865 | if (!locks_overlap(caller_fl, sys_fl)) | |
c0e15908 | 866 | return false; |
1da177e4 | 867 | |
c0e15908 | 868 | return locks_conflict(caller_fl, sys_fl); |
1da177e4 LT |
869 | } |
870 | ||
6c9007f6 SS |
871 | /* Determine if lock sys_fl blocks lock caller_fl. Used on xx_GETLK |
872 | * path so checks for additional GETLK-specific things like F_UNLCK. | |
873 | */ | |
874 | static bool posix_test_locks_conflict(struct file_lock *caller_fl, | |
875 | struct file_lock *sys_fl) | |
876 | { | |
877 | /* F_UNLCK checks any locks on the same fd. */ | |
878 | if (caller_fl->fl_type == F_UNLCK) { | |
879 | if (!posix_same_owner(caller_fl, sys_fl)) | |
880 | return false; | |
881 | return locks_overlap(caller_fl, sys_fl); | |
882 | } | |
883 | return posix_locks_conflict(caller_fl, sys_fl); | |
884 | } | |
885 | ||
1da177e4 LT |
886 | /* Determine if lock sys_fl blocks lock caller_fl. FLOCK specific |
887 | * checking before calling the locks_conflict(). | |
888 | */ | |
c0e15908 N |
889 | static bool flock_locks_conflict(struct file_lock *caller_fl, |
890 | struct file_lock *sys_fl) | |
1da177e4 LT |
891 | { |
892 | /* FLOCK locks referring to the same filp do not conflict with | |
893 | * each other. | |
894 | */ | |
9b8c8695 | 895 | if (caller_fl->fl_file == sys_fl->fl_file) |
c0e15908 | 896 | return false; |
1da177e4 | 897 | |
c0e15908 | 898 | return locks_conflict(caller_fl, sys_fl); |
1da177e4 LT |
899 | } |
900 | ||
6d34ac19 | 901 | void |
9d6a8c5c | 902 | posix_test_lock(struct file *filp, struct file_lock *fl) |
1da177e4 LT |
903 | { |
904 | struct file_lock *cfl; | |
bd61e0a9 | 905 | struct file_lock_context *ctx; |
c65454a9 | 906 | struct inode *inode = file_inode(filp); |
2443da22 DN |
907 | void *owner; |
908 | void (*func)(void); | |
1da177e4 | 909 | |
401a8b8f | 910 | ctx = locks_inode_context(inode); |
bd61e0a9 JL |
911 | if (!ctx || list_empty_careful(&ctx->flc_posix)) { |
912 | fl->fl_type = F_UNLCK; | |
913 | return; | |
914 | } | |
915 | ||
2443da22 | 916 | retry: |
6109c850 | 917 | spin_lock(&ctx->flc_lock); |
bd61e0a9 | 918 | list_for_each_entry(cfl, &ctx->flc_posix, fl_list) { |
6c9007f6 | 919 | if (!posix_test_locks_conflict(fl, cfl)) |
2443da22 DN |
920 | continue; |
921 | if (cfl->fl_lmops && cfl->fl_lmops->lm_lock_expirable | |
922 | && (*cfl->fl_lmops->lm_lock_expirable)(cfl)) { | |
923 | owner = cfl->fl_lmops->lm_mod_owner; | |
924 | func = cfl->fl_lmops->lm_expire_lock; | |
925 | __module_get(owner); | |
926 | spin_unlock(&ctx->flc_lock); | |
927 | (*func)(); | |
928 | module_put(owner); | |
929 | goto retry; | |
bd61e0a9 | 930 | } |
2443da22 DN |
931 | locks_copy_conflock(fl, cfl); |
932 | goto out; | |
1da177e4 | 933 | } |
bd61e0a9 JL |
934 | fl->fl_type = F_UNLCK; |
935 | out: | |
6109c850 | 936 | spin_unlock(&ctx->flc_lock); |
6d34ac19 | 937 | return; |
1da177e4 | 938 | } |
1da177e4 LT |
939 | EXPORT_SYMBOL(posix_test_lock); |
940 | ||
b533184f BF |
941 | /* |
942 | * Deadlock detection: | |
943 | * | |
944 | * We attempt to detect deadlocks that are due purely to posix file | |
945 | * locks. | |
1da177e4 | 946 | * |
b533184f BF |
947 | * We assume that a task can be waiting for at most one lock at a time. |
948 | * So for any acquired lock, the process holding that lock may be | |
949 | * waiting on at most one other lock. That lock in turns may be held by | |
950 | * someone waiting for at most one other lock. Given a requested lock | |
951 | * caller_fl which is about to wait for a conflicting lock block_fl, we | |
952 | * follow this chain of waiters to ensure we are not about to create a | |
953 | * cycle. | |
1da177e4 | 954 | * |
b533184f BF |
955 | * Since we do this before we ever put a process to sleep on a lock, we |
956 | * are ensured that there is never a cycle; that is what guarantees that | |
957 | * the while() loop in posix_locks_deadlock() eventually completes. | |
97855b49 | 958 | * |
b533184f BF |
959 | * Note: the above assumption may not be true when handling lock |
960 | * requests from a broken NFS client. It may also fail in the presence | |
961 | * of tasks (such as posix threads) sharing the same open file table. | |
b533184f | 962 | * To handle those cases, we just bail out after a few iterations. |
57b65325 | 963 | * |
cff2fce5 | 964 | * For FL_OFDLCK locks, the owner is the filp, not the files_struct. |
57b65325 JL |
965 | * Because the owner is not even nominally tied to a thread of |
966 | * execution, the deadlock detection below can't reasonably work well. Just | |
967 | * skip it for those. | |
968 | * | |
cff2fce5 | 969 | * In principle, we could do a more limited deadlock detection on FL_OFDLCK |
57b65325 JL |
970 | * locks that just checks for the case where two tasks are attempting to |
971 | * upgrade from read to write locks on the same inode. | |
1da177e4 | 972 | */ |
97855b49 BF |
973 | |
974 | #define MAX_DEADLK_ITERATIONS 10 | |
975 | ||
b533184f BF |
976 | /* Find a lock that the owner of the given block_fl is blocking on. */ |
977 | static struct file_lock *what_owner_is_waiting_for(struct file_lock *block_fl) | |
978 | { | |
979 | struct file_lock *fl; | |
980 | ||
3999e493 | 981 | hash_for_each_possible(blocked_hash, fl, fl_link, posix_owner_key(block_fl)) { |
5946c431 N |
982 | if (posix_same_owner(fl, block_fl)) { |
983 | while (fl->fl_blocker) | |
984 | fl = fl->fl_blocker; | |
985 | return fl; | |
986 | } | |
b533184f BF |
987 | } |
988 | return NULL; | |
989 | } | |
990 | ||
7b2296af | 991 | /* Must be called with the blocked_lock_lock held! */ |
b0904e14 | 992 | static int posix_locks_deadlock(struct file_lock *caller_fl, |
1da177e4 LT |
993 | struct file_lock *block_fl) |
994 | { | |
97855b49 | 995 | int i = 0; |
1da177e4 | 996 | |
663d5af7 DW |
997 | lockdep_assert_held(&blocked_lock_lock); |
998 | ||
57b65325 JL |
999 | /* |
1000 | * This deadlock detector can't reasonably detect deadlocks with | |
cff2fce5 | 1001 | * FL_OFDLCK locks, since they aren't owned by a process, per-se. |
57b65325 | 1002 | */ |
cff2fce5 | 1003 | if (IS_OFDLCK(caller_fl)) |
57b65325 JL |
1004 | return 0; |
1005 | ||
b533184f BF |
1006 | while ((block_fl = what_owner_is_waiting_for(block_fl))) { |
1007 | if (i++ > MAX_DEADLK_ITERATIONS) | |
1008 | return 0; | |
1009 | if (posix_same_owner(caller_fl, block_fl)) | |
1010 | return 1; | |
1da177e4 LT |
1011 | } |
1012 | return 0; | |
1013 | } | |
1014 | ||
1da177e4 | 1015 | /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks |
02888f41 | 1016 | * after any leases, but before any posix locks. |
f475ae95 TM |
1017 | * |
1018 | * Note that if called with an FL_EXISTS argument, the caller may determine | |
1019 | * whether or not a lock was successfully freed by testing the return | |
1020 | * value for -ENOENT. | |
1da177e4 | 1021 | */ |
bcd7f78d | 1022 | static int flock_lock_inode(struct inode *inode, struct file_lock *request) |
1da177e4 | 1023 | { |
993dfa87 | 1024 | struct file_lock *new_fl = NULL; |
5263e31e JL |
1025 | struct file_lock *fl; |
1026 | struct file_lock_context *ctx; | |
1da177e4 | 1027 | int error = 0; |
5263e31e | 1028 | bool found = false; |
ed9814d8 | 1029 | LIST_HEAD(dispose); |
1da177e4 | 1030 | |
5c1c669a JL |
1031 | ctx = locks_get_lock_context(inode, request->fl_type); |
1032 | if (!ctx) { | |
1033 | if (request->fl_type != F_UNLCK) | |
1034 | return -ENOMEM; | |
1035 | return (request->fl_flags & FL_EXISTS) ? -ENOENT : 0; | |
1036 | } | |
5263e31e | 1037 | |
b89f4321 | 1038 | if (!(request->fl_flags & FL_ACCESS) && (request->fl_type != F_UNLCK)) { |
84d535ad | 1039 | new_fl = locks_alloc_lock(); |
b89f4321 AB |
1040 | if (!new_fl) |
1041 | return -ENOMEM; | |
84d535ad PE |
1042 | } |
1043 | ||
02e525b2 | 1044 | percpu_down_read(&file_rwsem); |
6109c850 | 1045 | spin_lock(&ctx->flc_lock); |
b89f4321 AB |
1046 | if (request->fl_flags & FL_ACCESS) |
1047 | goto find_conflict; | |
1048 | ||
5263e31e | 1049 | list_for_each_entry(fl, &ctx->flc_flock, fl_list) { |
bcd7f78d | 1050 | if (request->fl_file != fl->fl_file) |
1da177e4 | 1051 | continue; |
993dfa87 | 1052 | if (request->fl_type == fl->fl_type) |
1da177e4 | 1053 | goto out; |
5263e31e | 1054 | found = true; |
e084c1bd | 1055 | locks_delete_lock_ctx(fl, &dispose); |
1da177e4 LT |
1056 | break; |
1057 | } | |
1da177e4 | 1058 | |
f475ae95 TM |
1059 | if (request->fl_type == F_UNLCK) { |
1060 | if ((request->fl_flags & FL_EXISTS) && !found) | |
1061 | error = -ENOENT; | |
993dfa87 | 1062 | goto out; |
f475ae95 | 1063 | } |
1da177e4 | 1064 | |
f07f18dd | 1065 | find_conflict: |
5263e31e | 1066 | list_for_each_entry(fl, &ctx->flc_flock, fl_list) { |
993dfa87 | 1067 | if (!flock_locks_conflict(request, fl)) |
1da177e4 LT |
1068 | continue; |
1069 | error = -EAGAIN; | |
bde74e4b MS |
1070 | if (!(request->fl_flags & FL_SLEEP)) |
1071 | goto out; | |
1072 | error = FILE_LOCK_DEFERRED; | |
fd7732e0 | 1073 | locks_insert_block(fl, request, flock_locks_conflict); |
1da177e4 LT |
1074 | goto out; |
1075 | } | |
f07f18dd TM |
1076 | if (request->fl_flags & FL_ACCESS) |
1077 | goto out; | |
993dfa87 | 1078 | locks_copy_lock(new_fl, request); |
5946c431 | 1079 | locks_move_blocks(new_fl, request); |
e084c1bd | 1080 | locks_insert_lock_ctx(new_fl, &ctx->flc_flock); |
993dfa87 | 1081 | new_fl = NULL; |
9cedc194 | 1082 | error = 0; |
1da177e4 LT |
1083 | |
1084 | out: | |
6109c850 | 1085 | spin_unlock(&ctx->flc_lock); |
02e525b2 | 1086 | percpu_up_read(&file_rwsem); |
993dfa87 TM |
1087 | if (new_fl) |
1088 | locks_free_lock(new_fl); | |
ed9814d8 | 1089 | locks_dispose_list(&dispose); |
c883da31 | 1090 | trace_flock_lock_inode(inode, request, error); |
1da177e4 LT |
1091 | return error; |
1092 | } | |
1093 | ||
b4d629a3 JL |
1094 | static int posix_lock_inode(struct inode *inode, struct file_lock *request, |
1095 | struct file_lock *conflock) | |
1da177e4 | 1096 | { |
bd61e0a9 | 1097 | struct file_lock *fl, *tmp; |
39005d02 MS |
1098 | struct file_lock *new_fl = NULL; |
1099 | struct file_lock *new_fl2 = NULL; | |
1da177e4 LT |
1100 | struct file_lock *left = NULL; |
1101 | struct file_lock *right = NULL; | |
bd61e0a9 | 1102 | struct file_lock_context *ctx; |
b9746ef8 JL |
1103 | int error; |
1104 | bool added = false; | |
ed9814d8 | 1105 | LIST_HEAD(dispose); |
2443da22 DN |
1106 | void *owner; |
1107 | void (*func)(void); | |
1da177e4 | 1108 | |
5c1c669a | 1109 | ctx = locks_get_lock_context(inode, request->fl_type); |
bd61e0a9 | 1110 | if (!ctx) |
5c1c669a | 1111 | return (request->fl_type == F_UNLCK) ? 0 : -ENOMEM; |
bd61e0a9 | 1112 | |
1da177e4 LT |
1113 | /* |
1114 | * We may need two file_lock structures for this operation, | |
1115 | * so we get them in advance to avoid races. | |
39005d02 MS |
1116 | * |
1117 | * In some cases we can be sure, that no new locks will be needed | |
1da177e4 | 1118 | */ |
39005d02 MS |
1119 | if (!(request->fl_flags & FL_ACCESS) && |
1120 | (request->fl_type != F_UNLCK || | |
1121 | request->fl_start != 0 || request->fl_end != OFFSET_MAX)) { | |
1122 | new_fl = locks_alloc_lock(); | |
1123 | new_fl2 = locks_alloc_lock(); | |
1124 | } | |
1da177e4 | 1125 | |
2443da22 | 1126 | retry: |
02e525b2 | 1127 | percpu_down_read(&file_rwsem); |
6109c850 | 1128 | spin_lock(&ctx->flc_lock); |
1cb36012 JL |
1129 | /* |
1130 | * New lock request. Walk all POSIX locks and look for conflicts. If | |
1131 | * there are any, either return error or put the request on the | |
48f74186 | 1132 | * blocker's list of waiters and the global blocked_hash. |
1cb36012 | 1133 | */ |
1da177e4 | 1134 | if (request->fl_type != F_UNLCK) { |
bd61e0a9 | 1135 | list_for_each_entry(fl, &ctx->flc_posix, fl_list) { |
1da177e4 LT |
1136 | if (!posix_locks_conflict(request, fl)) |
1137 | continue; | |
2443da22 DN |
1138 | if (fl->fl_lmops && fl->fl_lmops->lm_lock_expirable |
1139 | && (*fl->fl_lmops->lm_lock_expirable)(fl)) { | |
1140 | owner = fl->fl_lmops->lm_mod_owner; | |
1141 | func = fl->fl_lmops->lm_expire_lock; | |
1142 | __module_get(owner); | |
1143 | spin_unlock(&ctx->flc_lock); | |
1144 | percpu_up_read(&file_rwsem); | |
1145 | (*func)(); | |
1146 | module_put(owner); | |
1147 | goto retry; | |
1148 | } | |
5842add2 | 1149 | if (conflock) |
3fe0fff1 | 1150 | locks_copy_conflock(conflock, fl); |
1da177e4 LT |
1151 | error = -EAGAIN; |
1152 | if (!(request->fl_flags & FL_SLEEP)) | |
1153 | goto out; | |
1c8c601a JL |
1154 | /* |
1155 | * Deadlock detection and insertion into the blocked | |
1156 | * locks list must be done while holding the same lock! | |
1157 | */ | |
1da177e4 | 1158 | error = -EDEADLK; |
7b2296af | 1159 | spin_lock(&blocked_lock_lock); |
945ab8f6 JL |
1160 | /* |
1161 | * Ensure that we don't find any locks blocked on this | |
1162 | * request during deadlock detection. | |
1163 | */ | |
1164 | __locks_wake_up_blocks(request); | |
1c8c601a JL |
1165 | if (likely(!posix_locks_deadlock(request, fl))) { |
1166 | error = FILE_LOCK_DEFERRED; | |
fd7732e0 N |
1167 | __locks_insert_block(fl, request, |
1168 | posix_locks_conflict); | |
1c8c601a | 1169 | } |
7b2296af | 1170 | spin_unlock(&blocked_lock_lock); |
1da177e4 | 1171 | goto out; |
7bbd1fc0 N |
1172 | } |
1173 | } | |
1da177e4 LT |
1174 | |
1175 | /* If we're just looking for a conflict, we're done. */ | |
1176 | error = 0; | |
1177 | if (request->fl_flags & FL_ACCESS) | |
1178 | goto out; | |
1179 | ||
bd61e0a9 JL |
1180 | /* Find the first old lock with the same owner as the new lock */ |
1181 | list_for_each_entry(fl, &ctx->flc_posix, fl_list) { | |
1182 | if (posix_same_owner(request, fl)) | |
1183 | break; | |
1da177e4 LT |
1184 | } |
1185 | ||
1cb36012 | 1186 | /* Process locks with this owner. */ |
bd61e0a9 JL |
1187 | list_for_each_entry_safe_from(fl, tmp, &ctx->flc_posix, fl_list) { |
1188 | if (!posix_same_owner(request, fl)) | |
1189 | break; | |
1190 | ||
1191 | /* Detect adjacent or overlapping regions (if same lock type) */ | |
1da177e4 | 1192 | if (request->fl_type == fl->fl_type) { |
449231d6 OK |
1193 | /* In all comparisons of start vs end, use |
1194 | * "start - 1" rather than "end + 1". If end | |
1195 | * is OFFSET_MAX, end + 1 will become negative. | |
1196 | */ | |
1da177e4 | 1197 | if (fl->fl_end < request->fl_start - 1) |
bd61e0a9 | 1198 | continue; |
1da177e4 LT |
1199 | /* If the next lock in the list has entirely bigger |
1200 | * addresses than the new one, insert the lock here. | |
1201 | */ | |
449231d6 | 1202 | if (fl->fl_start - 1 > request->fl_end) |
1da177e4 LT |
1203 | break; |
1204 | ||
1205 | /* If we come here, the new and old lock are of the | |
1206 | * same type and adjacent or overlapping. Make one | |
1207 | * lock yielding from the lower start address of both | |
1208 | * locks to the higher end address. | |
1209 | */ | |
1210 | if (fl->fl_start > request->fl_start) | |
1211 | fl->fl_start = request->fl_start; | |
1212 | else | |
1213 | request->fl_start = fl->fl_start; | |
1214 | if (fl->fl_end < request->fl_end) | |
1215 | fl->fl_end = request->fl_end; | |
1216 | else | |
1217 | request->fl_end = fl->fl_end; | |
1218 | if (added) { | |
e084c1bd | 1219 | locks_delete_lock_ctx(fl, &dispose); |
1da177e4 LT |
1220 | continue; |
1221 | } | |
1222 | request = fl; | |
b9746ef8 | 1223 | added = true; |
bd61e0a9 | 1224 | } else { |
1da177e4 LT |
1225 | /* Processing for different lock types is a bit |
1226 | * more complex. | |
1227 | */ | |
1228 | if (fl->fl_end < request->fl_start) | |
bd61e0a9 | 1229 | continue; |
1da177e4 LT |
1230 | if (fl->fl_start > request->fl_end) |
1231 | break; | |
1232 | if (request->fl_type == F_UNLCK) | |
b9746ef8 | 1233 | added = true; |
1da177e4 LT |
1234 | if (fl->fl_start < request->fl_start) |
1235 | left = fl; | |
1236 | /* If the next lock in the list has a higher end | |
1237 | * address than the new one, insert the new one here. | |
1238 | */ | |
1239 | if (fl->fl_end > request->fl_end) { | |
1240 | right = fl; | |
1241 | break; | |
1242 | } | |
1243 | if (fl->fl_start >= request->fl_start) { | |
1244 | /* The new lock completely replaces an old | |
1245 | * one (This may happen several times). | |
1246 | */ | |
1247 | if (added) { | |
e084c1bd | 1248 | locks_delete_lock_ctx(fl, &dispose); |
1da177e4 LT |
1249 | continue; |
1250 | } | |
b84d49f9 JL |
1251 | /* |
1252 | * Replace the old lock with new_fl, and | |
1253 | * remove the old one. It's safe to do the | |
1254 | * insert here since we know that we won't be | |
1255 | * using new_fl later, and that the lock is | |
1256 | * just replacing an existing lock. | |
1da177e4 | 1257 | */ |
b84d49f9 JL |
1258 | error = -ENOLCK; |
1259 | if (!new_fl) | |
1260 | goto out; | |
1261 | locks_copy_lock(new_fl, request); | |
5ef15968 | 1262 | locks_move_blocks(new_fl, request); |
b84d49f9 JL |
1263 | request = new_fl; |
1264 | new_fl = NULL; | |
e084c1bd JL |
1265 | locks_insert_lock_ctx(request, &fl->fl_list); |
1266 | locks_delete_lock_ctx(fl, &dispose); | |
b9746ef8 | 1267 | added = true; |
1da177e4 LT |
1268 | } |
1269 | } | |
1da177e4 LT |
1270 | } |
1271 | ||
0d9a490a | 1272 | /* |
1cb36012 JL |
1273 | * The above code only modifies existing locks in case of merging or |
1274 | * replacing. If new lock(s) need to be inserted all modifications are | |
1275 | * done below this, so it's safe yet to bail out. | |
0d9a490a MS |
1276 | */ |
1277 | error = -ENOLCK; /* "no luck" */ | |
1278 | if (right && left == right && !new_fl2) | |
1279 | goto out; | |
1280 | ||
1da177e4 LT |
1281 | error = 0; |
1282 | if (!added) { | |
f475ae95 TM |
1283 | if (request->fl_type == F_UNLCK) { |
1284 | if (request->fl_flags & FL_EXISTS) | |
1285 | error = -ENOENT; | |
1da177e4 | 1286 | goto out; |
f475ae95 | 1287 | } |
0d9a490a MS |
1288 | |
1289 | if (!new_fl) { | |
1290 | error = -ENOLCK; | |
1291 | goto out; | |
1292 | } | |
1da177e4 | 1293 | locks_copy_lock(new_fl, request); |
5946c431 | 1294 | locks_move_blocks(new_fl, request); |
e084c1bd | 1295 | locks_insert_lock_ctx(new_fl, &fl->fl_list); |
2e2f756f | 1296 | fl = new_fl; |
1da177e4 LT |
1297 | new_fl = NULL; |
1298 | } | |
1299 | if (right) { | |
1300 | if (left == right) { | |
1301 | /* The new lock breaks the old one in two pieces, | |
1302 | * so we have to use the second new lock. | |
1303 | */ | |
1304 | left = new_fl2; | |
1305 | new_fl2 = NULL; | |
1306 | locks_copy_lock(left, right); | |
e084c1bd | 1307 | locks_insert_lock_ctx(left, &fl->fl_list); |
1da177e4 LT |
1308 | } |
1309 | right->fl_start = request->fl_end + 1; | |
1310 | locks_wake_up_blocks(right); | |
1311 | } | |
1312 | if (left) { | |
1313 | left->fl_end = request->fl_start - 1; | |
1314 | locks_wake_up_blocks(left); | |
1315 | } | |
1316 | out: | |
6109c850 | 1317 | spin_unlock(&ctx->flc_lock); |
02e525b2 | 1318 | percpu_up_read(&file_rwsem); |
74f6f591 | 1319 | trace_posix_lock_inode(inode, request, error); |
1da177e4 LT |
1320 | /* |
1321 | * Free any unused locks. | |
1322 | */ | |
1323 | if (new_fl) | |
1324 | locks_free_lock(new_fl); | |
1325 | if (new_fl2) | |
1326 | locks_free_lock(new_fl2); | |
ed9814d8 | 1327 | locks_dispose_list(&dispose); |
1890910f | 1328 | |
1da177e4 LT |
1329 | return error; |
1330 | } | |
1331 | ||
1332 | /** | |
1333 | * posix_lock_file - Apply a POSIX-style lock to a file | |
1334 | * @filp: The file to apply the lock to | |
1335 | * @fl: The lock to be applied | |
150b3934 | 1336 | * @conflock: Place to return a copy of the conflicting lock, if found. |
1da177e4 LT |
1337 | * |
1338 | * Add a POSIX style lock to a file. | |
1339 | * We merge adjacent & overlapping locks whenever possible. | |
1340 | * POSIX locks are sorted by owner task, then by starting address | |
f475ae95 TM |
1341 | * |
1342 | * Note that if called with an FL_EXISTS argument, the caller may determine | |
1343 | * whether or not a lock was successfully freed by testing the return | |
1344 | * value for -ENOENT. | |
1da177e4 | 1345 | */ |
150b3934 | 1346 | int posix_lock_file(struct file *filp, struct file_lock *fl, |
5842add2 AA |
1347 | struct file_lock *conflock) |
1348 | { | |
c65454a9 | 1349 | return posix_lock_inode(file_inode(filp), fl, conflock); |
1da177e4 | 1350 | } |
150b3934 | 1351 | EXPORT_SYMBOL(posix_lock_file); |
1da177e4 LT |
1352 | |
1353 | /** | |
29d01b22 JL |
1354 | * posix_lock_inode_wait - Apply a POSIX-style lock to a file |
1355 | * @inode: inode of file to which lock request should be applied | |
1da177e4 LT |
1356 | * @fl: The lock to be applied |
1357 | * | |
616fb38f | 1358 | * Apply a POSIX style lock request to an inode. |
1da177e4 | 1359 | */ |
616fb38f | 1360 | static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl) |
1da177e4 LT |
1361 | { |
1362 | int error; | |
1363 | might_sleep (); | |
1364 | for (;;) { | |
b4d629a3 | 1365 | error = posix_lock_inode(inode, fl, NULL); |
bde74e4b | 1366 | if (error != FILE_LOCK_DEFERRED) |
1da177e4 | 1367 | break; |
dcf23ac3 LT |
1368 | error = wait_event_interruptible(fl->fl_wait, |
1369 | list_empty(&fl->fl_blocked_member)); | |
16306a61 N |
1370 | if (error) |
1371 | break; | |
1da177e4 | 1372 | } |
16306a61 | 1373 | locks_delete_block(fl); |
1da177e4 LT |
1374 | return error; |
1375 | } | |
29d01b22 | 1376 | |
778fc546 BF |
1377 | static void lease_clear_pending(struct file_lock *fl, int arg) |
1378 | { | |
1379 | switch (arg) { | |
1380 | case F_UNLCK: | |
1381 | fl->fl_flags &= ~FL_UNLOCK_PENDING; | |
df561f66 | 1382 | fallthrough; |
778fc546 BF |
1383 | case F_RDLCK: |
1384 | fl->fl_flags &= ~FL_DOWNGRADE_PENDING; | |
1385 | } | |
1386 | } | |
1387 | ||
1da177e4 | 1388 | /* We already had a lease on this file; just change its type */ |
7448cc37 | 1389 | int lease_modify(struct file_lock *fl, int arg, struct list_head *dispose) |
1da177e4 | 1390 | { |
1da177e4 LT |
1391 | int error = assign_type(fl, arg); |
1392 | ||
1393 | if (error) | |
1394 | return error; | |
778fc546 | 1395 | lease_clear_pending(fl, arg); |
1da177e4 | 1396 | locks_wake_up_blocks(fl); |
3b6e2723 FB |
1397 | if (arg == F_UNLCK) { |
1398 | struct file *filp = fl->fl_file; | |
1399 | ||
1400 | f_delown(filp); | |
1401 | filp->f_owner.signum = 0; | |
96d6d59c BF |
1402 | fasync_helper(0, fl->fl_file, 0, &fl->fl_fasync); |
1403 | if (fl->fl_fasync != NULL) { | |
1404 | printk(KERN_ERR "locks_delete_lock: fasync == %p\n", fl->fl_fasync); | |
1405 | fl->fl_fasync = NULL; | |
1406 | } | |
e084c1bd | 1407 | locks_delete_lock_ctx(fl, dispose); |
3b6e2723 | 1408 | } |
1da177e4 LT |
1409 | return 0; |
1410 | } | |
1da177e4 LT |
1411 | EXPORT_SYMBOL(lease_modify); |
1412 | ||
778fc546 BF |
1413 | static bool past_time(unsigned long then) |
1414 | { | |
1415 | if (!then) | |
1416 | /* 0 is a special value meaning "this never expires": */ | |
1417 | return false; | |
1418 | return time_after(jiffies, then); | |
1419 | } | |
1420 | ||
c45198ed | 1421 | static void time_out_leases(struct inode *inode, struct list_head *dispose) |
1da177e4 | 1422 | { |
8634b51f JL |
1423 | struct file_lock_context *ctx = inode->i_flctx; |
1424 | struct file_lock *fl, *tmp; | |
1da177e4 | 1425 | |
6109c850 | 1426 | lockdep_assert_held(&ctx->flc_lock); |
f82b4b67 | 1427 | |
8634b51f | 1428 | list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) { |
62af4f1f | 1429 | trace_time_out_leases(inode, fl); |
778fc546 | 1430 | if (past_time(fl->fl_downgrade_time)) |
7448cc37 | 1431 | lease_modify(fl, F_RDLCK, dispose); |
778fc546 | 1432 | if (past_time(fl->fl_break_time)) |
7448cc37 | 1433 | lease_modify(fl, F_UNLCK, dispose); |
1da177e4 LT |
1434 | } |
1435 | } | |
1436 | ||
df4e8d2c BF |
1437 | static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker) |
1438 | { | |
d51f527f IW |
1439 | bool rc; |
1440 | ||
28df3d15 BF |
1441 | if (lease->fl_lmops->lm_breaker_owns_lease |
1442 | && lease->fl_lmops->lm_breaker_owns_lease(lease)) | |
1443 | return false; | |
d51f527f IW |
1444 | if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT)) { |
1445 | rc = false; | |
1446 | goto trace; | |
1447 | } | |
1448 | if ((breaker->fl_flags & FL_DELEG) && (lease->fl_flags & FL_LEASE)) { | |
1449 | rc = false; | |
1450 | goto trace; | |
1451 | } | |
1452 | ||
1453 | rc = locks_conflict(breaker, lease); | |
1454 | trace: | |
1455 | trace_leases_conflict(rc, lease, breaker); | |
1456 | return rc; | |
df4e8d2c BF |
1457 | } |
1458 | ||
03d12ddf JL |
1459 | static bool |
1460 | any_leases_conflict(struct inode *inode, struct file_lock *breaker) | |
1461 | { | |
8634b51f | 1462 | struct file_lock_context *ctx = inode->i_flctx; |
03d12ddf JL |
1463 | struct file_lock *fl; |
1464 | ||
6109c850 | 1465 | lockdep_assert_held(&ctx->flc_lock); |
03d12ddf | 1466 | |
8634b51f | 1467 | list_for_each_entry(fl, &ctx->flc_lease, fl_list) { |
03d12ddf JL |
1468 | if (leases_conflict(fl, breaker)) |
1469 | return true; | |
1470 | } | |
1471 | return false; | |
1472 | } | |
1473 | ||
1da177e4 LT |
1474 | /** |
1475 | * __break_lease - revoke all outstanding leases on file | |
1476 | * @inode: the inode of the file to return | |
df4e8d2c BF |
1477 | * @mode: O_RDONLY: break only write leases; O_WRONLY or O_RDWR: |
1478 | * break all leases | |
1479 | * @type: FL_LEASE: break leases and delegations; FL_DELEG: break | |
1480 | * only delegations | |
1da177e4 | 1481 | * |
87250dd2 | 1482 | * break_lease (inlined for speed) has checked there already is at least |
1483 | * some kind of lock (maybe a lease) on this file. Leases are broken on | |
1484 | * a call to open() or truncate(). This function can sleep unless you | |
1da177e4 LT |
1485 | * specified %O_NONBLOCK to your open(). |
1486 | */ | |
df4e8d2c | 1487 | int __break_lease(struct inode *inode, unsigned int mode, unsigned int type) |
1da177e4 | 1488 | { |
778fc546 | 1489 | int error = 0; |
128a3785 | 1490 | struct file_lock_context *ctx; |
a901125c | 1491 | struct file_lock *new_fl, *fl, *tmp; |
1da177e4 | 1492 | unsigned long break_time; |
8737c930 | 1493 | int want_write = (mode & O_ACCMODE) != O_RDONLY; |
c45198ed | 1494 | LIST_HEAD(dispose); |
1da177e4 | 1495 | |
8737c930 | 1496 | new_fl = lease_alloc(NULL, want_write ? F_WRLCK : F_RDLCK); |
6d4b9e38 LT |
1497 | if (IS_ERR(new_fl)) |
1498 | return PTR_ERR(new_fl); | |
df4e8d2c | 1499 | new_fl->fl_flags = type; |
1da177e4 | 1500 | |
8634b51f | 1501 | /* typically we will check that ctx is non-NULL before calling */ |
401a8b8f | 1502 | ctx = locks_inode_context(inode); |
8634b51f JL |
1503 | if (!ctx) { |
1504 | WARN_ON_ONCE(1); | |
cfddf9f4 | 1505 | goto free_lock; |
8634b51f JL |
1506 | } |
1507 | ||
02e525b2 | 1508 | percpu_down_read(&file_rwsem); |
6109c850 | 1509 | spin_lock(&ctx->flc_lock); |
1da177e4 | 1510 | |
c45198ed | 1511 | time_out_leases(inode, &dispose); |
1da177e4 | 1512 | |
03d12ddf | 1513 | if (!any_leases_conflict(inode, new_fl)) |
778fc546 BF |
1514 | goto out; |
1515 | ||
1da177e4 LT |
1516 | break_time = 0; |
1517 | if (lease_break_time > 0) { | |
1518 | break_time = jiffies + lease_break_time * HZ; | |
1519 | if (break_time == 0) | |
1520 | break_time++; /* so that 0 means no break time */ | |
1521 | } | |
1522 | ||
a901125c | 1523 | list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) { |
df4e8d2c BF |
1524 | if (!leases_conflict(fl, new_fl)) |
1525 | continue; | |
778fc546 BF |
1526 | if (want_write) { |
1527 | if (fl->fl_flags & FL_UNLOCK_PENDING) | |
1528 | continue; | |
1529 | fl->fl_flags |= FL_UNLOCK_PENDING; | |
1da177e4 | 1530 | fl->fl_break_time = break_time; |
778fc546 | 1531 | } else { |
8634b51f | 1532 | if (lease_breaking(fl)) |
778fc546 BF |
1533 | continue; |
1534 | fl->fl_flags |= FL_DOWNGRADE_PENDING; | |
1535 | fl->fl_downgrade_time = break_time; | |
1da177e4 | 1536 | } |
4d01b7f5 | 1537 | if (fl->fl_lmops->lm_break(fl)) |
e084c1bd | 1538 | locks_delete_lock_ctx(fl, &dispose); |
1da177e4 LT |
1539 | } |
1540 | ||
8634b51f | 1541 | if (list_empty(&ctx->flc_lease)) |
4d01b7f5 JL |
1542 | goto out; |
1543 | ||
843c6b2f | 1544 | if (mode & O_NONBLOCK) { |
62af4f1f | 1545 | trace_break_lease_noblock(inode, new_fl); |
1da177e4 LT |
1546 | error = -EWOULDBLOCK; |
1547 | goto out; | |
1548 | } | |
1549 | ||
1550 | restart: | |
8634b51f JL |
1551 | fl = list_first_entry(&ctx->flc_lease, struct file_lock, fl_list); |
1552 | break_time = fl->fl_break_time; | |
f1c6bb2c | 1553 | if (break_time != 0) |
1da177e4 | 1554 | break_time -= jiffies; |
f1c6bb2c JL |
1555 | if (break_time == 0) |
1556 | break_time++; | |
fd7732e0 | 1557 | locks_insert_block(fl, new_fl, leases_conflict); |
62af4f1f | 1558 | trace_break_lease_block(inode, new_fl); |
6109c850 | 1559 | spin_unlock(&ctx->flc_lock); |
02e525b2 | 1560 | percpu_up_read(&file_rwsem); |
aba37660 | 1561 | |
c45198ed | 1562 | locks_dispose_list(&dispose); |
4321e01e | 1563 | error = wait_event_interruptible_timeout(new_fl->fl_wait, |
dcf23ac3 LT |
1564 | list_empty(&new_fl->fl_blocked_member), |
1565 | break_time); | |
aba37660 | 1566 | |
02e525b2 | 1567 | percpu_down_read(&file_rwsem); |
6109c850 | 1568 | spin_lock(&ctx->flc_lock); |
62af4f1f | 1569 | trace_break_lease_unblock(inode, new_fl); |
1c8c601a | 1570 | locks_delete_block(new_fl); |
1da177e4 | 1571 | if (error >= 0) { |
778fc546 BF |
1572 | /* |
1573 | * Wait for the next conflicting lease that has not been | |
1574 | * broken yet | |
1575 | */ | |
03d12ddf JL |
1576 | if (error == 0) |
1577 | time_out_leases(inode, &dispose); | |
1578 | if (any_leases_conflict(inode, new_fl)) | |
1579 | goto restart; | |
1da177e4 LT |
1580 | error = 0; |
1581 | } | |
1da177e4 | 1582 | out: |
6109c850 | 1583 | spin_unlock(&ctx->flc_lock); |
02e525b2 | 1584 | percpu_up_read(&file_rwsem); |
c45198ed | 1585 | locks_dispose_list(&dispose); |
cfddf9f4 | 1586 | free_lock: |
6d4b9e38 | 1587 | locks_free_lock(new_fl); |
1da177e4 LT |
1588 | return error; |
1589 | } | |
1da177e4 LT |
1590 | EXPORT_SYMBOL(__break_lease); |
1591 | ||
1592 | /** | |
76c47948 | 1593 | * lease_get_mtime - update modified time of an inode with exclusive lease |
1da177e4 | 1594 | * @inode: the inode |
76c47948 | 1595 | * @time: pointer to a timespec which contains the last modified time |
1da177e4 LT |
1596 | * |
1597 | * This is to force NFS clients to flush their caches for files with | |
1598 | * exclusive leases. The justification is that if someone has an | |
a6b91919 | 1599 | * exclusive lease, then they could be modifying it. |
1da177e4 | 1600 | */ |
95582b00 | 1601 | void lease_get_mtime(struct inode *inode, struct timespec64 *time) |
1da177e4 | 1602 | { |
bfe86024 | 1603 | bool has_lease = false; |
128a3785 | 1604 | struct file_lock_context *ctx; |
8634b51f | 1605 | struct file_lock *fl; |
bfe86024 | 1606 | |
401a8b8f | 1607 | ctx = locks_inode_context(inode); |
8634b51f | 1608 | if (ctx && !list_empty_careful(&ctx->flc_lease)) { |
6109c850 | 1609 | spin_lock(&ctx->flc_lock); |
8ace5dfb GT |
1610 | fl = list_first_entry_or_null(&ctx->flc_lease, |
1611 | struct file_lock, fl_list); | |
1612 | if (fl && (fl->fl_type == F_WRLCK)) | |
1613 | has_lease = true; | |
6109c850 | 1614 | spin_unlock(&ctx->flc_lock); |
bfe86024 JL |
1615 | } |
1616 | ||
1617 | if (has_lease) | |
c2050a45 | 1618 | *time = current_time(inode); |
1da177e4 | 1619 | } |
1da177e4 LT |
1620 | EXPORT_SYMBOL(lease_get_mtime); |
1621 | ||
1622 | /** | |
1623 | * fcntl_getlease - Enquire what lease is currently active | |
1624 | * @filp: the file | |
1625 | * | |
1626 | * The value returned by this function will be one of | |
1627 | * (if no lease break is pending): | |
1628 | * | |
1629 | * %F_RDLCK to indicate a shared lease is held. | |
1630 | * | |
1631 | * %F_WRLCK to indicate an exclusive lease is held. | |
1632 | * | |
1633 | * %F_UNLCK to indicate no lease is held. | |
1634 | * | |
1635 | * (if a lease break is pending): | |
1636 | * | |
1637 | * %F_RDLCK to indicate an exclusive lease needs to be | |
1638 | * changed to a shared lease (or removed). | |
1639 | * | |
1640 | * %F_UNLCK to indicate the lease needs to be removed. | |
1641 | * | |
1642 | * XXX: sfr & willy disagree over whether F_INPROGRESS | |
1643 | * should be returned to userspace. | |
1644 | */ | |
1645 | int fcntl_getlease(struct file *filp) | |
1646 | { | |
1647 | struct file_lock *fl; | |
c65454a9 | 1648 | struct inode *inode = file_inode(filp); |
128a3785 | 1649 | struct file_lock_context *ctx; |
1da177e4 | 1650 | int type = F_UNLCK; |
c45198ed | 1651 | LIST_HEAD(dispose); |
1da177e4 | 1652 | |
401a8b8f | 1653 | ctx = locks_inode_context(inode); |
8634b51f | 1654 | if (ctx && !list_empty_careful(&ctx->flc_lease)) { |
02e525b2 | 1655 | percpu_down_read(&file_rwsem); |
6109c850 | 1656 | spin_lock(&ctx->flc_lock); |
c568d683 | 1657 | time_out_leases(inode, &dispose); |
8634b51f JL |
1658 | list_for_each_entry(fl, &ctx->flc_lease, fl_list) { |
1659 | if (fl->fl_file != filp) | |
1660 | continue; | |
778fc546 | 1661 | type = target_leasetype(fl); |
1da177e4 LT |
1662 | break; |
1663 | } | |
6109c850 | 1664 | spin_unlock(&ctx->flc_lock); |
02e525b2 | 1665 | percpu_up_read(&file_rwsem); |
5f43086b | 1666 | |
8634b51f | 1667 | locks_dispose_list(&dispose); |
1da177e4 | 1668 | } |
1da177e4 LT |
1669 | return type; |
1670 | } | |
1671 | ||
24cbe784 | 1672 | /** |
387e3746 | 1673 | * check_conflicting_open - see if the given file points to an inode that has |
7bbd1fc0 N |
1674 | * an existing open that would conflict with the |
1675 | * desired lease. | |
387e3746 | 1676 | * @filp: file to check |
24cbe784 | 1677 | * @arg: type of lease that we're trying to acquire |
7fadc59c | 1678 | * @flags: current lock flags |
24cbe784 JL |
1679 | * |
1680 | * Check to see if there's an existing open fd on this file that would | |
1681 | * conflict with the lease we're trying to set. | |
1682 | */ | |
1683 | static int | |
ed5f17f6 | 1684 | check_conflicting_open(struct file *filp, const int arg, int flags) |
24cbe784 | 1685 | { |
c65454a9 | 1686 | struct inode *inode = file_inode(filp); |
387e3746 | 1687 | int self_wcount = 0, self_rcount = 0; |
24cbe784 | 1688 | |
11afe9f7 CH |
1689 | if (flags & FL_LAYOUT) |
1690 | return 0; | |
aba2072f BF |
1691 | if (flags & FL_DELEG) |
1692 | /* We leave these checks to the caller */ | |
1693 | return 0; | |
11afe9f7 | 1694 | |
387e3746 AG |
1695 | if (arg == F_RDLCK) |
1696 | return inode_is_open_for_write(inode) ? -EAGAIN : 0; | |
1697 | else if (arg != F_WRLCK) | |
1698 | return 0; | |
1699 | ||
1700 | /* | |
1701 | * Make sure that only read/write count is from lease requestor. | |
1702 | * Note that this will result in denying write leases when i_writecount | |
1703 | * is negative, which is what we want. (We shouldn't grant write leases | |
1704 | * on files open for execution.) | |
1705 | */ | |
1706 | if (filp->f_mode & FMODE_WRITE) | |
1707 | self_wcount = 1; | |
1708 | else if (filp->f_mode & FMODE_READ) | |
1709 | self_rcount = 1; | |
24cbe784 | 1710 | |
387e3746 AG |
1711 | if (atomic_read(&inode->i_writecount) != self_wcount || |
1712 | atomic_read(&inode->i_readcount) != self_rcount) | |
1713 | return -EAGAIN; | |
24cbe784 | 1714 | |
387e3746 | 1715 | return 0; |
24cbe784 JL |
1716 | } |
1717 | ||
e6f5c789 | 1718 | static int |
ed5f17f6 | 1719 | generic_add_lease(struct file *filp, int arg, struct file_lock **flp, void **priv) |
1da177e4 | 1720 | { |
8634b51f | 1721 | struct file_lock *fl, *my_fl = NULL, *lease; |
c65454a9 | 1722 | struct inode *inode = file_inode(filp); |
8634b51f | 1723 | struct file_lock_context *ctx; |
df4e8d2c | 1724 | bool is_deleg = (*flp)->fl_flags & FL_DELEG; |
c1f24ef4 | 1725 | int error; |
c45198ed | 1726 | LIST_HEAD(dispose); |
1da177e4 | 1727 | |
096657b6 | 1728 | lease = *flp; |
62af4f1f JL |
1729 | trace_generic_add_lease(inode, lease); |
1730 | ||
5c1c669a JL |
1731 | /* Note that arg is never F_UNLCK here */ |
1732 | ctx = locks_get_lock_context(inode, arg); | |
8634b51f JL |
1733 | if (!ctx) |
1734 | return -ENOMEM; | |
1735 | ||
df4e8d2c BF |
1736 | /* |
1737 | * In the delegation case we need mutual exclusion with | |
1738 | * a number of operations that take the i_mutex. We trylock | |
1739 | * because delegations are an optional optimization, and if | |
1740 | * there's some chance of a conflict--we'd rather not | |
1741 | * bother, maybe that's a sign this just isn't a good file to | |
1742 | * hand out a delegation on. | |
1743 | */ | |
5955102c | 1744 | if (is_deleg && !inode_trylock(inode)) |
df4e8d2c BF |
1745 | return -EAGAIN; |
1746 | ||
02e525b2 | 1747 | percpu_down_read(&file_rwsem); |
6109c850 | 1748 | spin_lock(&ctx->flc_lock); |
c45198ed | 1749 | time_out_leases(inode, &dispose); |
387e3746 | 1750 | error = check_conflicting_open(filp, arg, lease->fl_flags); |
24cbe784 | 1751 | if (error) |
096657b6 | 1752 | goto out; |
6d5e8b05 | 1753 | |
1da177e4 LT |
1754 | /* |
1755 | * At this point, we know that if there is an exclusive | |
1756 | * lease on this file, then we hold it on this filp | |
1757 | * (otherwise our open of this file would have blocked). | |
1758 | * And if we are trying to acquire an exclusive lease, | |
1759 | * then the file is not open by anyone (including us) | |
1760 | * except for this filp. | |
1761 | */ | |
c1f24ef4 | 1762 | error = -EAGAIN; |
8634b51f | 1763 | list_for_each_entry(fl, &ctx->flc_lease, fl_list) { |
2ab99ee1 CH |
1764 | if (fl->fl_file == filp && |
1765 | fl->fl_owner == lease->fl_owner) { | |
8634b51f | 1766 | my_fl = fl; |
c1f24ef4 BF |
1767 | continue; |
1768 | } | |
8634b51f | 1769 | |
c1f24ef4 BF |
1770 | /* |
1771 | * No exclusive leases if someone else has a lease on | |
1772 | * this file: | |
1773 | */ | |
1774 | if (arg == F_WRLCK) | |
1775 | goto out; | |
1776 | /* | |
1777 | * Modifying our existing lease is OK, but no getting a | |
1778 | * new lease if someone else is opening for write: | |
1779 | */ | |
1780 | if (fl->fl_flags & FL_UNLOCK_PENDING) | |
1781 | goto out; | |
1da177e4 LT |
1782 | } |
1783 | ||
8634b51f | 1784 | if (my_fl != NULL) { |
0164bf02 JL |
1785 | lease = my_fl; |
1786 | error = lease->fl_lmops->lm_change(lease, arg, &dispose); | |
1c7dd2ff JL |
1787 | if (error) |
1788 | goto out; | |
1789 | goto out_setup; | |
1da177e4 LT |
1790 | } |
1791 | ||
1da177e4 LT |
1792 | error = -EINVAL; |
1793 | if (!leases_enable) | |
1794 | goto out; | |
1795 | ||
e084c1bd | 1796 | locks_insert_lock_ctx(lease, &ctx->flc_lease); |
24cbe784 JL |
1797 | /* |
1798 | * The check in break_lease() is lockless. It's possible for another | |
1799 | * open to race in after we did the earlier check for a conflicting | |
1800 | * open but before the lease was inserted. Check again for a | |
1801 | * conflicting open and cancel the lease if there is one. | |
1802 | * | |
1803 | * We also add a barrier here to ensure that the insertion of the lock | |
1804 | * precedes these checks. | |
1805 | */ | |
1806 | smp_mb(); | |
387e3746 | 1807 | error = check_conflicting_open(filp, arg, lease->fl_flags); |
8634b51f | 1808 | if (error) { |
e084c1bd | 1809 | locks_unlink_lock_ctx(lease); |
8634b51f JL |
1810 | goto out; |
1811 | } | |
1c7dd2ff JL |
1812 | |
1813 | out_setup: | |
1814 | if (lease->fl_lmops->lm_setup) | |
1815 | lease->fl_lmops->lm_setup(lease, priv); | |
1da177e4 | 1816 | out: |
6109c850 | 1817 | spin_unlock(&ctx->flc_lock); |
02e525b2 | 1818 | percpu_up_read(&file_rwsem); |
c45198ed | 1819 | locks_dispose_list(&dispose); |
df4e8d2c | 1820 | if (is_deleg) |
5955102c | 1821 | inode_unlock(inode); |
8634b51f | 1822 | if (!error && !my_fl) |
1c7dd2ff | 1823 | *flp = NULL; |
1da177e4 LT |
1824 | return error; |
1825 | } | |
8335ebd9 | 1826 | |
2ab99ee1 | 1827 | static int generic_delete_lease(struct file *filp, void *owner) |
8335ebd9 | 1828 | { |
0efaa7e8 | 1829 | int error = -EAGAIN; |
8634b51f | 1830 | struct file_lock *fl, *victim = NULL; |
c65454a9 | 1831 | struct inode *inode = file_inode(filp); |
128a3785 | 1832 | struct file_lock_context *ctx; |
c45198ed | 1833 | LIST_HEAD(dispose); |
8335ebd9 | 1834 | |
401a8b8f | 1835 | ctx = locks_inode_context(inode); |
8634b51f JL |
1836 | if (!ctx) { |
1837 | trace_generic_delete_lease(inode, NULL); | |
1838 | return error; | |
1839 | } | |
1840 | ||
02e525b2 | 1841 | percpu_down_read(&file_rwsem); |
6109c850 | 1842 | spin_lock(&ctx->flc_lock); |
8634b51f | 1843 | list_for_each_entry(fl, &ctx->flc_lease, fl_list) { |
2ab99ee1 CH |
1844 | if (fl->fl_file == filp && |
1845 | fl->fl_owner == owner) { | |
8634b51f | 1846 | victim = fl; |
0efaa7e8 | 1847 | break; |
8634b51f | 1848 | } |
8335ebd9 | 1849 | } |
a9b1b455 | 1850 | trace_generic_delete_lease(inode, victim); |
8634b51f | 1851 | if (victim) |
7448cc37 | 1852 | error = fl->fl_lmops->lm_change(victim, F_UNLCK, &dispose); |
6109c850 | 1853 | spin_unlock(&ctx->flc_lock); |
02e525b2 | 1854 | percpu_up_read(&file_rwsem); |
c45198ed | 1855 | locks_dispose_list(&dispose); |
0efaa7e8 | 1856 | return error; |
8335ebd9 BF |
1857 | } |
1858 | ||
1859 | /** | |
1860 | * generic_setlease - sets a lease on an open file | |
1c7dd2ff JL |
1861 | * @filp: file pointer |
1862 | * @arg: type of lease to obtain | |
1863 | * @flp: input - file_lock to use, output - file_lock inserted | |
1864 | * @priv: private data for lm_setup (may be NULL if lm_setup | |
1865 | * doesn't require it) | |
8335ebd9 BF |
1866 | * |
1867 | * The (input) flp->fl_lmops->lm_break function is required | |
1868 | * by break_lease(). | |
8335ebd9 | 1869 | */ |
ed5f17f6 | 1870 | int generic_setlease(struct file *filp, int arg, struct file_lock **flp, |
e6f5c789 | 1871 | void **priv) |
8335ebd9 | 1872 | { |
c65454a9 | 1873 | struct inode *inode = file_inode(filp); |
42d0c4bd | 1874 | vfsuid_t vfsuid = i_uid_into_vfsuid(file_mnt_idmap(filp), inode); |
8335ebd9 BF |
1875 | int error; |
1876 | ||
42d0c4bd | 1877 | if ((!vfsuid_eq_kuid(vfsuid, current_fsuid())) && !capable(CAP_LEASE)) |
8335ebd9 BF |
1878 | return -EACCES; |
1879 | if (!S_ISREG(inode->i_mode)) | |
1880 | return -EINVAL; | |
1881 | error = security_file_lock(filp, arg); | |
1882 | if (error) | |
1883 | return error; | |
1884 | ||
8335ebd9 BF |
1885 | switch (arg) { |
1886 | case F_UNLCK: | |
2ab99ee1 | 1887 | return generic_delete_lease(filp, *priv); |
8335ebd9 BF |
1888 | case F_RDLCK: |
1889 | case F_WRLCK: | |
0efaa7e8 JL |
1890 | if (!(*flp)->fl_lmops->lm_break) { |
1891 | WARN_ON_ONCE(1); | |
1892 | return -ENOLCK; | |
1893 | } | |
11afe9f7 | 1894 | |
e6f5c789 | 1895 | return generic_add_lease(filp, arg, flp, priv); |
8335ebd9 | 1896 | default: |
8d657eb3 | 1897 | return -EINVAL; |
8335ebd9 BF |
1898 | } |
1899 | } | |
0af1a450 | 1900 | EXPORT_SYMBOL(generic_setlease); |
1da177e4 | 1901 | |
18f6622e JL |
1902 | /* |
1903 | * Kernel subsystems can register to be notified on any attempt to set | |
1904 | * a new lease with the lease_notifier_chain. This is used by (e.g.) nfsd | |
1905 | * to close files that it may have cached when there is an attempt to set a | |
1906 | * conflicting lease. | |
1907 | */ | |
1908 | static struct srcu_notifier_head lease_notifier_chain; | |
1909 | ||
1910 | static inline void | |
1911 | lease_notifier_chain_init(void) | |
1912 | { | |
1913 | srcu_init_notifier_head(&lease_notifier_chain); | |
1914 | } | |
1915 | ||
1916 | static inline void | |
ed5f17f6 | 1917 | setlease_notifier(int arg, struct file_lock *lease) |
18f6622e JL |
1918 | { |
1919 | if (arg != F_UNLCK) | |
1920 | srcu_notifier_call_chain(&lease_notifier_chain, arg, lease); | |
1921 | } | |
1922 | ||
1923 | int lease_register_notifier(struct notifier_block *nb) | |
1924 | { | |
1925 | return srcu_notifier_chain_register(&lease_notifier_chain, nb); | |
1926 | } | |
1927 | EXPORT_SYMBOL_GPL(lease_register_notifier); | |
1928 | ||
1929 | void lease_unregister_notifier(struct notifier_block *nb) | |
1930 | { | |
1931 | srcu_notifier_chain_unregister(&lease_notifier_chain, nb); | |
1932 | } | |
1933 | EXPORT_SYMBOL_GPL(lease_unregister_notifier); | |
1934 | ||
b89f4321 | 1935 | /** |
e51673aa | 1936 | * vfs_setlease - sets a lease on an open file |
1c7dd2ff JL |
1937 | * @filp: file pointer |
1938 | * @arg: type of lease to obtain | |
1939 | * @lease: file_lock to use when adding a lease | |
1940 | * @priv: private info for lm_setup when adding a lease (may be | |
7bbd1fc0 | 1941 | * NULL if lm_setup doesn't require it) |
e51673aa JL |
1942 | * |
1943 | * Call this to establish a lease on the file. The "lease" argument is not | |
1944 | * used for F_UNLCK requests and may be NULL. For commands that set or alter | |
80b79dd0 MCC |
1945 | * an existing lease, the ``(*lease)->fl_lmops->lm_break`` operation must be |
1946 | * set; if not, this function will return -ENOLCK (and generate a scary-looking | |
e51673aa | 1947 | * stack trace). |
1c7dd2ff JL |
1948 | * |
1949 | * The "priv" pointer is passed directly to the lm_setup function as-is. It | |
1950 | * may be NULL if the lm_setup operation doesn't require it. | |
1da177e4 | 1951 | */ |
e6f5c789 | 1952 | int |
ed5f17f6 | 1953 | vfs_setlease(struct file *filp, int arg, struct file_lock **lease, void **priv) |
1da177e4 | 1954 | { |
18f6622e JL |
1955 | if (lease) |
1956 | setlease_notifier(arg, *lease); | |
de2a4a50 | 1957 | if (filp->f_op->setlease) |
f82b4b67 | 1958 | return filp->f_op->setlease(filp, arg, lease, priv); |
1c7dd2ff | 1959 | else |
f82b4b67 | 1960 | return generic_setlease(filp, arg, lease, priv); |
1da177e4 | 1961 | } |
a9933cea | 1962 | EXPORT_SYMBOL_GPL(vfs_setlease); |
1da177e4 | 1963 | |
ed5f17f6 | 1964 | static int do_fcntl_add_lease(unsigned int fd, struct file *filp, int arg) |
1da177e4 | 1965 | { |
1c7dd2ff | 1966 | struct file_lock *fl; |
f7347ce4 | 1967 | struct fasync_struct *new; |
1da177e4 LT |
1968 | int error; |
1969 | ||
c5b1f0d9 AB |
1970 | fl = lease_alloc(filp, arg); |
1971 | if (IS_ERR(fl)) | |
1972 | return PTR_ERR(fl); | |
1da177e4 | 1973 | |
f7347ce4 LT |
1974 | new = fasync_alloc(); |
1975 | if (!new) { | |
1976 | locks_free_lock(fl); | |
1977 | return -ENOMEM; | |
1978 | } | |
1c7dd2ff | 1979 | new->fa_fd = fd; |
f7347ce4 | 1980 | |
1c7dd2ff | 1981 | error = vfs_setlease(filp, arg, &fl, (void **)&new); |
2dfb928f JL |
1982 | if (fl) |
1983 | locks_free_lock(fl); | |
f7347ce4 LT |
1984 | if (new) |
1985 | fasync_free(new); | |
1da177e4 LT |
1986 | return error; |
1987 | } | |
1988 | ||
0ceaf6c7 BF |
1989 | /** |
1990 | * fcntl_setlease - sets a lease on an open file | |
1991 | * @fd: open file descriptor | |
1992 | * @filp: file pointer | |
1993 | * @arg: type of lease to obtain | |
1994 | * | |
1995 | * Call this fcntl to establish a lease on the file. | |
1996 | * Note that you also need to call %F_SETSIG to | |
1997 | * receive a signal when the lease is broken. | |
1998 | */ | |
ed5f17f6 | 1999 | int fcntl_setlease(unsigned int fd, struct file *filp, int arg) |
0ceaf6c7 BF |
2000 | { |
2001 | if (arg == F_UNLCK) | |
2ab99ee1 | 2002 | return vfs_setlease(filp, F_UNLCK, NULL, (void **)&filp); |
0ceaf6c7 BF |
2003 | return do_fcntl_add_lease(fd, filp, arg); |
2004 | } | |
2005 | ||
1da177e4 | 2006 | /** |
29d01b22 JL |
2007 | * flock_lock_inode_wait - Apply a FLOCK-style lock to a file |
2008 | * @inode: inode of the file to apply to | |
1da177e4 LT |
2009 | * @fl: The lock to be applied |
2010 | * | |
29d01b22 | 2011 | * Apply a FLOCK style lock request to an inode. |
1da177e4 | 2012 | */ |
616fb38f | 2013 | static int flock_lock_inode_wait(struct inode *inode, struct file_lock *fl) |
1da177e4 LT |
2014 | { |
2015 | int error; | |
2016 | might_sleep(); | |
2017 | for (;;) { | |
29d01b22 | 2018 | error = flock_lock_inode(inode, fl); |
bde74e4b | 2019 | if (error != FILE_LOCK_DEFERRED) |
1da177e4 | 2020 | break; |
dcf23ac3 LT |
2021 | error = wait_event_interruptible(fl->fl_wait, |
2022 | list_empty(&fl->fl_blocked_member)); | |
16306a61 N |
2023 | if (error) |
2024 | break; | |
1da177e4 | 2025 | } |
16306a61 | 2026 | locks_delete_block(fl); |
1da177e4 LT |
2027 | return error; |
2028 | } | |
2029 | ||
e55c34a6 BC |
2030 | /** |
2031 | * locks_lock_inode_wait - Apply a lock to an inode | |
2032 | * @inode: inode of the file to apply to | |
2033 | * @fl: The lock to be applied | |
2034 | * | |
2035 | * Apply a POSIX or FLOCK style lock request to an inode. | |
2036 | */ | |
2037 | int locks_lock_inode_wait(struct inode *inode, struct file_lock *fl) | |
2038 | { | |
2039 | int res = 0; | |
2040 | switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) { | |
2041 | case FL_POSIX: | |
2042 | res = posix_lock_inode_wait(inode, fl); | |
2043 | break; | |
2044 | case FL_FLOCK: | |
2045 | res = flock_lock_inode_wait(inode, fl); | |
2046 | break; | |
2047 | default: | |
2048 | BUG(); | |
2049 | } | |
2050 | return res; | |
2051 | } | |
2052 | EXPORT_SYMBOL(locks_lock_inode_wait); | |
2053 | ||
1da177e4 LT |
2054 | /** |
2055 | * sys_flock: - flock() system call. | |
2056 | * @fd: the file descriptor to lock. | |
2057 | * @cmd: the type of lock to apply. | |
2058 | * | |
2059 | * Apply a %FL_FLOCK style lock to an open file descriptor. | |
80b79dd0 | 2060 | * The @cmd can be one of: |
1da177e4 | 2061 | * |
80b79dd0 MCC |
2062 | * - %LOCK_SH -- a shared lock. |
2063 | * - %LOCK_EX -- an exclusive lock. | |
2064 | * - %LOCK_UN -- remove an existing lock. | |
90f7d7a0 | 2065 | * - %LOCK_MAND -- a 'mandatory' flock. (DEPRECATED) |
1da177e4 | 2066 | * |
90f7d7a0 | 2067 | * %LOCK_MAND support has been removed from the kernel. |
1da177e4 | 2068 | */ |
002c8976 | 2069 | SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd) |
1da177e4 | 2070 | { |
db4abb4a | 2071 | int can_sleep, error, type; |
4149be7b | 2072 | struct file_lock fl; |
db4abb4a | 2073 | struct fd f; |
90f7d7a0 JL |
2074 | |
2075 | /* | |
2076 | * LOCK_MAND locks were broken for a long time in that they never | |
2077 | * conflicted with one another and didn't prevent any sort of open, | |
2078 | * read or write activity. | |
2079 | * | |
2080 | * Just ignore these requests now, to preserve legacy behavior, but | |
2081 | * throw a warning to let people know that they don't actually work. | |
2082 | */ | |
2083 | if (cmd & LOCK_MAND) { | |
f2f2494c | 2084 | 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); |
db4abb4a | 2085 | return 0; |
90f7d7a0 | 2086 | } |
1da177e4 | 2087 | |
db4abb4a KI |
2088 | type = flock_translate_cmd(cmd & ~LOCK_NB); |
2089 | if (type < 0) | |
2090 | return type; | |
2091 | ||
2092 | error = -EBADF; | |
2093 | f = fdget(fd); | |
2094 | if (!f.file) | |
2095 | return error; | |
2096 | ||
2097 | if (type != F_UNLCK && !(f.file->f_mode & (FMODE_READ | FMODE_WRITE))) | |
1da177e4 | 2098 | goto out_putf; |
6e129d00 | 2099 | |
4149be7b KI |
2100 | flock_make_lock(f.file, &fl, type); |
2101 | ||
4149be7b | 2102 | error = security_file_lock(f.file, fl.fl_type); |
1da177e4 | 2103 | if (error) |
4149be7b | 2104 | goto out_putf; |
1da177e4 | 2105 | |
db4abb4a KI |
2106 | can_sleep = !(cmd & LOCK_NB); |
2107 | if (can_sleep) | |
2108 | fl.fl_flags |= FL_SLEEP; | |
2109 | ||
de2a4a50 | 2110 | if (f.file->f_op->flock) |
2903ff01 | 2111 | error = f.file->f_op->flock(f.file, |
db4abb4a | 2112 | (can_sleep) ? F_SETLKW : F_SETLK, |
4149be7b | 2113 | &fl); |
1da177e4 | 2114 | else |
4149be7b | 2115 | error = locks_lock_file_wait(f.file, &fl); |
1da177e4 | 2116 | |
932c29a1 | 2117 | locks_release_private(&fl); |
1da177e4 | 2118 | out_putf: |
2903ff01 | 2119 | fdput(f); |
db4abb4a | 2120 | |
1da177e4 LT |
2121 | return error; |
2122 | } | |
2123 | ||
3ee17abd BF |
2124 | /** |
2125 | * vfs_test_lock - test file byte range lock | |
2126 | * @filp: The file to test lock for | |
6924c554 | 2127 | * @fl: The lock to test; also used to hold result |
3ee17abd BF |
2128 | * |
2129 | * Returns -ERRNO on failure. Indicates presence of conflicting lock by | |
2130 | * setting conf->fl_type to something other than F_UNLCK. | |
2131 | */ | |
2132 | int vfs_test_lock(struct file *filp, struct file_lock *fl) | |
2133 | { | |
7e8e5cc8 | 2134 | WARN_ON_ONCE(filp != fl->fl_file); |
de2a4a50 | 2135 | if (filp->f_op->lock) |
3ee17abd BF |
2136 | return filp->f_op->lock(filp, F_GETLK, fl); |
2137 | posix_test_lock(filp, fl); | |
2138 | return 0; | |
2139 | } | |
2140 | EXPORT_SYMBOL_GPL(vfs_test_lock); | |
2141 | ||
9d5b86ac BC |
2142 | /** |
2143 | * locks_translate_pid - translate a file_lock's fl_pid number into a namespace | |
2144 | * @fl: The file_lock who's fl_pid should be translated | |
2145 | * @ns: The namespace into which the pid should be translated | |
2146 | * | |
bd4c4680 | 2147 | * Used to translate a fl_pid into a namespace virtual pid number |
9d5b86ac BC |
2148 | */ |
2149 | static pid_t locks_translate_pid(struct file_lock *fl, struct pid_namespace *ns) | |
2150 | { | |
2151 | pid_t vnr; | |
2152 | struct pid *pid; | |
2153 | ||
2154 | if (IS_OFDLCK(fl)) | |
2155 | return -1; | |
2156 | if (IS_REMOTELCK(fl)) | |
2157 | return fl->fl_pid; | |
826d7bc9 KK |
2158 | /* |
2159 | * If the flock owner process is dead and its pid has been already | |
2160 | * freed, the translation below won't work, but we still want to show | |
2161 | * flock owner pid number in init pidns. | |
2162 | */ | |
2163 | if (ns == &init_pid_ns) | |
2164 | return (pid_t)fl->fl_pid; | |
9d5b86ac BC |
2165 | |
2166 | rcu_read_lock(); | |
2167 | pid = find_pid_ns(fl->fl_pid, &init_pid_ns); | |
2168 | vnr = pid_nr_ns(pid, ns); | |
2169 | rcu_read_unlock(); | |
2170 | return vnr; | |
2171 | } | |
2172 | ||
c2fa1b8a BF |
2173 | static int posix_lock_to_flock(struct flock *flock, struct file_lock *fl) |
2174 | { | |
9d5b86ac | 2175 | flock->l_pid = locks_translate_pid(fl, task_active_pid_ns(current)); |
c2fa1b8a BF |
2176 | #if BITS_PER_LONG == 32 |
2177 | /* | |
2178 | * Make sure we can represent the posix lock via | |
2179 | * legacy 32bit flock. | |
2180 | */ | |
2181 | if (fl->fl_start > OFFT_OFFSET_MAX) | |
2182 | return -EOVERFLOW; | |
2183 | if (fl->fl_end != OFFSET_MAX && fl->fl_end > OFFT_OFFSET_MAX) | |
2184 | return -EOVERFLOW; | |
2185 | #endif | |
2186 | flock->l_start = fl->fl_start; | |
2187 | flock->l_len = fl->fl_end == OFFSET_MAX ? 0 : | |
2188 | fl->fl_end - fl->fl_start + 1; | |
2189 | flock->l_whence = 0; | |
129a84de | 2190 | flock->l_type = fl->fl_type; |
c2fa1b8a BF |
2191 | return 0; |
2192 | } | |
2193 | ||
2194 | #if BITS_PER_LONG == 32 | |
2195 | static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl) | |
2196 | { | |
9d5b86ac | 2197 | flock->l_pid = locks_translate_pid(fl, task_active_pid_ns(current)); |
c2fa1b8a BF |
2198 | flock->l_start = fl->fl_start; |
2199 | flock->l_len = fl->fl_end == OFFSET_MAX ? 0 : | |
2200 | fl->fl_end - fl->fl_start + 1; | |
2201 | flock->l_whence = 0; | |
2202 | flock->l_type = fl->fl_type; | |
2203 | } | |
2204 | #endif | |
2205 | ||
1da177e4 LT |
2206 | /* Report the first existing lock that would conflict with l. |
2207 | * This implements the F_GETLK command of fcntl(). | |
2208 | */ | |
a75d30c7 | 2209 | int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock *flock) |
1da177e4 | 2210 | { |
52306e88 | 2211 | struct file_lock *fl; |
1da177e4 LT |
2212 | int error; |
2213 | ||
52306e88 BC |
2214 | fl = locks_alloc_lock(); |
2215 | if (fl == NULL) | |
2216 | return -ENOMEM; | |
1da177e4 | 2217 | error = -EINVAL; |
6c9007f6 SS |
2218 | if (cmd != F_OFD_GETLK && flock->l_type != F_RDLCK |
2219 | && flock->l_type != F_WRLCK) | |
1da177e4 LT |
2220 | goto out; |
2221 | ||
52306e88 | 2222 | error = flock_to_posix_lock(filp, fl, flock); |
1da177e4 LT |
2223 | if (error) |
2224 | goto out; | |
2225 | ||
0d3f7a2d | 2226 | if (cmd == F_OFD_GETLK) { |
90478939 | 2227 | error = -EINVAL; |
a75d30c7 | 2228 | if (flock->l_pid != 0) |
90478939 JL |
2229 | goto out; |
2230 | ||
52306e88 BC |
2231 | fl->fl_flags |= FL_OFDLCK; |
2232 | fl->fl_owner = filp; | |
5d50ffd7 JL |
2233 | } |
2234 | ||
52306e88 | 2235 | error = vfs_test_lock(filp, fl); |
3ee17abd BF |
2236 | if (error) |
2237 | goto out; | |
7bbd1fc0 | 2238 | |
52306e88 BC |
2239 | flock->l_type = fl->fl_type; |
2240 | if (fl->fl_type != F_UNLCK) { | |
2241 | error = posix_lock_to_flock(flock, fl); | |
c2fa1b8a | 2242 | if (error) |
52306e88 | 2243 | goto out; |
1da177e4 | 2244 | } |
1da177e4 | 2245 | out: |
52306e88 | 2246 | locks_free_lock(fl); |
1da177e4 LT |
2247 | return error; |
2248 | } | |
2249 | ||
7723ec97 ME |
2250 | /** |
2251 | * vfs_lock_file - file byte range lock | |
2252 | * @filp: The file to apply the lock to | |
2253 | * @cmd: type of locking operation (F_SETLK, F_GETLK, etc.) | |
2254 | * @fl: The lock to be applied | |
150b3934 ME |
2255 | * @conf: Place to return a copy of the conflicting lock, if found. |
2256 | * | |
2257 | * A caller that doesn't care about the conflicting lock may pass NULL | |
2258 | * as the final argument. | |
2259 | * | |
2260 | * If the filesystem defines a private ->lock() method, then @conf will | |
2261 | * be left unchanged; so a caller that cares should initialize it to | |
2262 | * some acceptable default. | |
2beb6614 ME |
2263 | * |
2264 | * To avoid blocking kernel daemons, such as lockd, that need to acquire POSIX | |
2265 | * locks, the ->lock() interface may return asynchronously, before the lock has | |
2266 | * been granted or denied by the underlying filesystem, if (and only if) | |
e70da176 AA |
2267 | * lm_grant is set. Additionally EXPORT_OP_ASYNC_LOCK in export_operations |
2268 | * flags need to be set. | |
2269 | * | |
2270 | * Callers expecting ->lock() to return asynchronously will only use F_SETLK, | |
2271 | * not F_SETLKW; they will set FL_SLEEP if (and only if) the request is for a | |
2272 | * blocking lock. When ->lock() does return asynchronously, it must return | |
2273 | * FILE_LOCK_DEFERRED, and call ->lm_grant() when the lock request completes. | |
2beb6614 | 2274 | * If the request is for non-blocking lock the file system should return |
bde74e4b MS |
2275 | * FILE_LOCK_DEFERRED then try to get the lock and call the callback routine |
2276 | * with the result. If the request timed out the callback routine will return a | |
2beb6614 ME |
2277 | * nonzero return code and the file system should release the lock. The file |
2278 | * system is also responsible to keep a corresponding posix lock when it | |
2279 | * grants a lock so the VFS can find out which locks are locally held and do | |
2280 | * the correct lock cleanup when required. | |
2281 | * The underlying filesystem must not drop the kernel lock or call | |
8fb47a4f | 2282 | * ->lm_grant() before returning to the caller with a FILE_LOCK_DEFERRED |
2beb6614 | 2283 | * return code. |
7723ec97 | 2284 | */ |
150b3934 | 2285 | int vfs_lock_file(struct file *filp, unsigned int cmd, struct file_lock *fl, struct file_lock *conf) |
7723ec97 | 2286 | { |
7e8e5cc8 | 2287 | WARN_ON_ONCE(filp != fl->fl_file); |
de2a4a50 | 2288 | if (filp->f_op->lock) |
7723ec97 ME |
2289 | return filp->f_op->lock(filp, cmd, fl); |
2290 | else | |
150b3934 | 2291 | return posix_lock_file(filp, fl, conf); |
7723ec97 ME |
2292 | } |
2293 | EXPORT_SYMBOL_GPL(vfs_lock_file); | |
2294 | ||
b648a6de MS |
2295 | static int do_lock_file_wait(struct file *filp, unsigned int cmd, |
2296 | struct file_lock *fl) | |
2297 | { | |
2298 | int error; | |
2299 | ||
2300 | error = security_file_lock(filp, fl->fl_type); | |
2301 | if (error) | |
2302 | return error; | |
2303 | ||
764c76b3 MS |
2304 | for (;;) { |
2305 | error = vfs_lock_file(filp, cmd, fl, NULL); | |
2306 | if (error != FILE_LOCK_DEFERRED) | |
b648a6de | 2307 | break; |
dcf23ac3 LT |
2308 | error = wait_event_interruptible(fl->fl_wait, |
2309 | list_empty(&fl->fl_blocked_member)); | |
16306a61 N |
2310 | if (error) |
2311 | break; | |
b648a6de | 2312 | } |
16306a61 | 2313 | locks_delete_block(fl); |
b648a6de MS |
2314 | |
2315 | return error; | |
2316 | } | |
2317 | ||
6ca7d910 | 2318 | /* Ensure that fl->fl_file has compatible f_mode for F_SETLK calls */ |
cf01f4ee JL |
2319 | static int |
2320 | check_fmode_for_setlk(struct file_lock *fl) | |
2321 | { | |
2322 | switch (fl->fl_type) { | |
2323 | case F_RDLCK: | |
2324 | if (!(fl->fl_file->f_mode & FMODE_READ)) | |
2325 | return -EBADF; | |
2326 | break; | |
2327 | case F_WRLCK: | |
2328 | if (!(fl->fl_file->f_mode & FMODE_WRITE)) | |
2329 | return -EBADF; | |
2330 | } | |
2331 | return 0; | |
2332 | } | |
2333 | ||
1da177e4 LT |
2334 | /* Apply the lock described by l to an open file descriptor. |
2335 | * This implements both the F_SETLK and F_SETLKW commands of fcntl(). | |
2336 | */ | |
c293621b | 2337 | int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd, |
a75d30c7 | 2338 | struct flock *flock) |
1da177e4 LT |
2339 | { |
2340 | struct file_lock *file_lock = locks_alloc_lock(); | |
c65454a9 | 2341 | struct inode *inode = file_inode(filp); |
0b2bac2f | 2342 | struct file *f; |
1da177e4 LT |
2343 | int error; |
2344 | ||
2345 | if (file_lock == NULL) | |
2346 | return -ENOLCK; | |
2347 | ||
a75d30c7 | 2348 | error = flock_to_posix_lock(filp, file_lock, flock); |
1da177e4 LT |
2349 | if (error) |
2350 | goto out; | |
5d50ffd7 | 2351 | |
cf01f4ee JL |
2352 | error = check_fmode_for_setlk(file_lock); |
2353 | if (error) | |
2354 | goto out; | |
2355 | ||
5d50ffd7 JL |
2356 | /* |
2357 | * If the cmd is requesting file-private locks, then set the | |
cff2fce5 | 2358 | * FL_OFDLCK flag and override the owner. |
5d50ffd7 JL |
2359 | */ |
2360 | switch (cmd) { | |
0d3f7a2d | 2361 | case F_OFD_SETLK: |
90478939 | 2362 | error = -EINVAL; |
a75d30c7 | 2363 | if (flock->l_pid != 0) |
90478939 JL |
2364 | goto out; |
2365 | ||
5d50ffd7 | 2366 | cmd = F_SETLK; |
cff2fce5 | 2367 | file_lock->fl_flags |= FL_OFDLCK; |
73a8f5f7 | 2368 | file_lock->fl_owner = filp; |
5d50ffd7 | 2369 | break; |
0d3f7a2d | 2370 | case F_OFD_SETLKW: |
90478939 | 2371 | error = -EINVAL; |
a75d30c7 | 2372 | if (flock->l_pid != 0) |
90478939 JL |
2373 | goto out; |
2374 | ||
5d50ffd7 | 2375 | cmd = F_SETLKW; |
cff2fce5 | 2376 | file_lock->fl_flags |= FL_OFDLCK; |
73a8f5f7 | 2377 | file_lock->fl_owner = filp; |
df561f66 | 2378 | fallthrough; |
5d50ffd7 | 2379 | case F_SETLKW: |
1da177e4 LT |
2380 | file_lock->fl_flags |= FL_SLEEP; |
2381 | } | |
5d50ffd7 | 2382 | |
b648a6de | 2383 | error = do_lock_file_wait(filp, cmd, file_lock); |
1da177e4 | 2384 | |
c293621b | 2385 | /* |
0752ba80 JL |
2386 | * Attempt to detect a close/fcntl race and recover by releasing the |
2387 | * lock that was just acquired. There is no need to do that when we're | |
2388 | * unlocking though, or for OFD locks. | |
c293621b | 2389 | */ |
0752ba80 JL |
2390 | if (!error && file_lock->fl_type != F_UNLCK && |
2391 | !(file_lock->fl_flags & FL_OFDLCK)) { | |
120ce2b0 | 2392 | struct files_struct *files = current->files; |
7f3697e2 JL |
2393 | /* |
2394 | * We need that spin_lock here - it prevents reordering between | |
2395 | * update of i_flctx->flc_posix and check for it done in | |
2396 | * close(). rcu_read_lock() wouldn't do. | |
2397 | */ | |
120ce2b0 EB |
2398 | spin_lock(&files->file_lock); |
2399 | f = files_lookup_fd_locked(files, fd); | |
2400 | spin_unlock(&files->file_lock); | |
7f3697e2 JL |
2401 | if (f != filp) { |
2402 | file_lock->fl_type = F_UNLCK; | |
2403 | error = do_lock_file_wait(filp, cmd, file_lock); | |
2404 | WARN_ON_ONCE(error); | |
2405 | error = -EBADF; | |
2406 | } | |
1da177e4 | 2407 | } |
c293621b | 2408 | out: |
1890910f | 2409 | trace_fcntl_setlk(inode, file_lock, error); |
1da177e4 LT |
2410 | locks_free_lock(file_lock); |
2411 | return error; | |
2412 | } | |
2413 | ||
2414 | #if BITS_PER_LONG == 32 | |
2415 | /* Report the first existing lock that would conflict with l. | |
2416 | * This implements the F_GETLK command of fcntl(). | |
2417 | */ | |
a75d30c7 | 2418 | int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 *flock) |
1da177e4 | 2419 | { |
52306e88 | 2420 | struct file_lock *fl; |
1da177e4 LT |
2421 | int error; |
2422 | ||
52306e88 BC |
2423 | fl = locks_alloc_lock(); |
2424 | if (fl == NULL) | |
2425 | return -ENOMEM; | |
2426 | ||
1da177e4 | 2427 | error = -EINVAL; |
6c9007f6 SS |
2428 | if (cmd != F_OFD_GETLK && flock->l_type != F_RDLCK |
2429 | && flock->l_type != F_WRLCK) | |
1da177e4 LT |
2430 | goto out; |
2431 | ||
52306e88 | 2432 | error = flock64_to_posix_lock(filp, fl, flock); |
1da177e4 LT |
2433 | if (error) |
2434 | goto out; | |
2435 | ||
0d3f7a2d | 2436 | if (cmd == F_OFD_GETLK) { |
90478939 | 2437 | error = -EINVAL; |
a75d30c7 | 2438 | if (flock->l_pid != 0) |
90478939 JL |
2439 | goto out; |
2440 | ||
52306e88 BC |
2441 | fl->fl_flags |= FL_OFDLCK; |
2442 | fl->fl_owner = filp; | |
5d50ffd7 JL |
2443 | } |
2444 | ||
52306e88 | 2445 | error = vfs_test_lock(filp, fl); |
3ee17abd BF |
2446 | if (error) |
2447 | goto out; | |
2448 | ||
52306e88 BC |
2449 | flock->l_type = fl->fl_type; |
2450 | if (fl->fl_type != F_UNLCK) | |
2451 | posix_lock_to_flock64(flock, fl); | |
f328296e | 2452 | |
1da177e4 | 2453 | out: |
52306e88 | 2454 | locks_free_lock(fl); |
1da177e4 LT |
2455 | return error; |
2456 | } | |
2457 | ||
2458 | /* Apply the lock described by l to an open file descriptor. | |
2459 | * This implements both the F_SETLK and F_SETLKW commands of fcntl(). | |
2460 | */ | |
c293621b | 2461 | int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd, |
a75d30c7 | 2462 | struct flock64 *flock) |
1da177e4 LT |
2463 | { |
2464 | struct file_lock *file_lock = locks_alloc_lock(); | |
0b2bac2f | 2465 | struct file *f; |
1da177e4 LT |
2466 | int error; |
2467 | ||
2468 | if (file_lock == NULL) | |
2469 | return -ENOLCK; | |
2470 | ||
a75d30c7 | 2471 | error = flock64_to_posix_lock(filp, file_lock, flock); |
1da177e4 LT |
2472 | if (error) |
2473 | goto out; | |
5d50ffd7 | 2474 | |
cf01f4ee JL |
2475 | error = check_fmode_for_setlk(file_lock); |
2476 | if (error) | |
2477 | goto out; | |
2478 | ||
5d50ffd7 JL |
2479 | /* |
2480 | * If the cmd is requesting file-private locks, then set the | |
cff2fce5 | 2481 | * FL_OFDLCK flag and override the owner. |
5d50ffd7 JL |
2482 | */ |
2483 | switch (cmd) { | |
0d3f7a2d | 2484 | case F_OFD_SETLK: |
90478939 | 2485 | error = -EINVAL; |
a75d30c7 | 2486 | if (flock->l_pid != 0) |
90478939 JL |
2487 | goto out; |
2488 | ||
5d50ffd7 | 2489 | cmd = F_SETLK64; |
cff2fce5 | 2490 | file_lock->fl_flags |= FL_OFDLCK; |
73a8f5f7 | 2491 | file_lock->fl_owner = filp; |
5d50ffd7 | 2492 | break; |
0d3f7a2d | 2493 | case F_OFD_SETLKW: |
90478939 | 2494 | error = -EINVAL; |
a75d30c7 | 2495 | if (flock->l_pid != 0) |
90478939 JL |
2496 | goto out; |
2497 | ||
5d50ffd7 | 2498 | cmd = F_SETLKW64; |
cff2fce5 | 2499 | file_lock->fl_flags |= FL_OFDLCK; |
73a8f5f7 | 2500 | file_lock->fl_owner = filp; |
df561f66 | 2501 | fallthrough; |
5d50ffd7 | 2502 | case F_SETLKW64: |
1da177e4 LT |
2503 | file_lock->fl_flags |= FL_SLEEP; |
2504 | } | |
5d50ffd7 | 2505 | |
b648a6de | 2506 | error = do_lock_file_wait(filp, cmd, file_lock); |
1da177e4 | 2507 | |
c293621b | 2508 | /* |
0752ba80 JL |
2509 | * Attempt to detect a close/fcntl race and recover by releasing the |
2510 | * lock that was just acquired. There is no need to do that when we're | |
2511 | * unlocking though, or for OFD locks. | |
c293621b | 2512 | */ |
0752ba80 JL |
2513 | if (!error && file_lock->fl_type != F_UNLCK && |
2514 | !(file_lock->fl_flags & FL_OFDLCK)) { | |
120ce2b0 | 2515 | struct files_struct *files = current->files; |
7f3697e2 JL |
2516 | /* |
2517 | * We need that spin_lock here - it prevents reordering between | |
2518 | * update of i_flctx->flc_posix and check for it done in | |
2519 | * close(). rcu_read_lock() wouldn't do. | |
2520 | */ | |
120ce2b0 EB |
2521 | spin_lock(&files->file_lock); |
2522 | f = files_lookup_fd_locked(files, fd); | |
2523 | spin_unlock(&files->file_lock); | |
7f3697e2 JL |
2524 | if (f != filp) { |
2525 | file_lock->fl_type = F_UNLCK; | |
2526 | error = do_lock_file_wait(filp, cmd, file_lock); | |
2527 | WARN_ON_ONCE(error); | |
2528 | error = -EBADF; | |
2529 | } | |
1da177e4 | 2530 | } |
1da177e4 LT |
2531 | out: |
2532 | locks_free_lock(file_lock); | |
2533 | return error; | |
2534 | } | |
2535 | #endif /* BITS_PER_LONG == 32 */ | |
2536 | ||
2537 | /* | |
2538 | * This function is called when the file is being removed | |
2539 | * from the task's fd array. POSIX locks belonging to this task | |
2540 | * are deleted at this time. | |
2541 | */ | |
2542 | void locks_remove_posix(struct file *filp, fl_owner_t owner) | |
2543 | { | |
1890910f | 2544 | int error; |
c65454a9 | 2545 | struct inode *inode = file_inode(filp); |
ff7b86b8 | 2546 | struct file_lock lock; |
128a3785 | 2547 | struct file_lock_context *ctx; |
1da177e4 LT |
2548 | |
2549 | /* | |
2550 | * If there are no locks held on this file, we don't need to call | |
2551 | * posix_lock_file(). Another process could be setting a lock on this | |
2552 | * file at the same time, but we wouldn't remove that lock anyway. | |
2553 | */ | |
401a8b8f | 2554 | ctx = locks_inode_context(inode); |
bd61e0a9 | 2555 | if (!ctx || list_empty(&ctx->flc_posix)) |
1da177e4 LT |
2556 | return; |
2557 | ||
d6367d62 | 2558 | locks_init_lock(&lock); |
1da177e4 | 2559 | lock.fl_type = F_UNLCK; |
75e1fcc0 | 2560 | lock.fl_flags = FL_POSIX | FL_CLOSE; |
1da177e4 LT |
2561 | lock.fl_start = 0; |
2562 | lock.fl_end = OFFSET_MAX; | |
2563 | lock.fl_owner = owner; | |
2564 | lock.fl_pid = current->tgid; | |
2565 | lock.fl_file = filp; | |
2566 | lock.fl_ops = NULL; | |
2567 | lock.fl_lmops = NULL; | |
2568 | ||
1890910f | 2569 | error = vfs_lock_file(filp, F_SETLK, &lock, NULL); |
1da177e4 | 2570 | |
1da177e4 LT |
2571 | if (lock.fl_ops && lock.fl_ops->fl_release_private) |
2572 | lock.fl_ops->fl_release_private(&lock); | |
c568d683 | 2573 | trace_locks_remove_posix(inode, &lock, error); |
1da177e4 | 2574 | } |
1da177e4 LT |
2575 | EXPORT_SYMBOL(locks_remove_posix); |
2576 | ||
3d8e560d | 2577 | /* The i_flctx must be valid when calling into here */ |
dd459bb1 | 2578 | static void |
128a3785 | 2579 | locks_remove_flock(struct file *filp, struct file_lock_context *flctx) |
dd459bb1 | 2580 | { |
d6367d62 | 2581 | struct file_lock fl; |
c65454a9 | 2582 | struct inode *inode = file_inode(filp); |
dd459bb1 | 2583 | |
3d8e560d | 2584 | if (list_empty(&flctx->flc_flock)) |
dd459bb1 JL |
2585 | return; |
2586 | ||
4149be7b | 2587 | flock_make_lock(filp, &fl, F_UNLCK); |
d6367d62 N |
2588 | fl.fl_flags |= FL_CLOSE; |
2589 | ||
de2a4a50 | 2590 | if (filp->f_op->flock) |
dd459bb1 JL |
2591 | filp->f_op->flock(filp, F_SETLKW, &fl); |
2592 | else | |
bcd7f78d | 2593 | flock_lock_inode(inode, &fl); |
dd459bb1 JL |
2594 | |
2595 | if (fl.fl_ops && fl.fl_ops->fl_release_private) | |
2596 | fl.fl_ops->fl_release_private(&fl); | |
2597 | } | |
2598 | ||
3d8e560d | 2599 | /* The i_flctx must be valid when calling into here */ |
8634b51f | 2600 | static void |
128a3785 | 2601 | locks_remove_lease(struct file *filp, struct file_lock_context *ctx) |
8634b51f | 2602 | { |
8634b51f JL |
2603 | struct file_lock *fl, *tmp; |
2604 | LIST_HEAD(dispose); | |
2605 | ||
3d8e560d | 2606 | if (list_empty(&ctx->flc_lease)) |
8634b51f JL |
2607 | return; |
2608 | ||
02e525b2 | 2609 | percpu_down_read(&file_rwsem); |
6109c850 | 2610 | spin_lock(&ctx->flc_lock); |
8634b51f | 2611 | list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list) |
c4e136cd JL |
2612 | if (filp == fl->fl_file) |
2613 | lease_modify(fl, F_UNLCK, &dispose); | |
6109c850 | 2614 | spin_unlock(&ctx->flc_lock); |
02e525b2 | 2615 | percpu_up_read(&file_rwsem); |
5f43086b | 2616 | |
8634b51f JL |
2617 | locks_dispose_list(&dispose); |
2618 | } | |
2619 | ||
1da177e4 LT |
2620 | /* |
2621 | * This function is called on the last close of an open file. | |
2622 | */ | |
78ed8a13 | 2623 | void locks_remove_file(struct file *filp) |
1da177e4 | 2624 | { |
128a3785 DV |
2625 | struct file_lock_context *ctx; |
2626 | ||
c65454a9 | 2627 | ctx = locks_inode_context(file_inode(filp)); |
128a3785 | 2628 | if (!ctx) |
3d8e560d JL |
2629 | return; |
2630 | ||
dd459bb1 | 2631 | /* remove any OFD locks */ |
73a8f5f7 | 2632 | locks_remove_posix(filp, filp); |
5d50ffd7 | 2633 | |
dd459bb1 | 2634 | /* remove flock locks */ |
128a3785 | 2635 | locks_remove_flock(filp, ctx); |
dd459bb1 | 2636 | |
8634b51f | 2637 | /* remove any leases */ |
128a3785 | 2638 | locks_remove_lease(filp, ctx); |
3953704f BC |
2639 | |
2640 | spin_lock(&ctx->flc_lock); | |
2641 | locks_check_ctx_file_list(filp, &ctx->flc_posix, "POSIX"); | |
2642 | locks_check_ctx_file_list(filp, &ctx->flc_flock, "FLOCK"); | |
2643 | locks_check_ctx_file_list(filp, &ctx->flc_lease, "LEASE"); | |
2644 | spin_unlock(&ctx->flc_lock); | |
1da177e4 LT |
2645 | } |
2646 | ||
9b9d2ab4 ME |
2647 | /** |
2648 | * vfs_cancel_lock - file byte range unblock lock | |
2649 | * @filp: The file to apply the unblock to | |
2650 | * @fl: The lock to be unblocked | |
2651 | * | |
2652 | * Used by lock managers to cancel blocked requests | |
2653 | */ | |
2654 | int vfs_cancel_lock(struct file *filp, struct file_lock *fl) | |
2655 | { | |
7e8e5cc8 | 2656 | WARN_ON_ONCE(filp != fl->fl_file); |
de2a4a50 | 2657 | if (filp->f_op->lock) |
9b9d2ab4 ME |
2658 | return filp->f_op->lock(filp, F_CANCELLK, fl); |
2659 | return 0; | |
2660 | } | |
9b9d2ab4 ME |
2661 | EXPORT_SYMBOL_GPL(vfs_cancel_lock); |
2662 | ||
ab1ddef9 JL |
2663 | /** |
2664 | * vfs_inode_has_locks - are any file locks held on @inode? | |
2665 | * @inode: inode to check for locks | |
2666 | * | |
2667 | * Return true if there are any FL_POSIX or FL_FLOCK locks currently | |
2668 | * set on @inode. | |
2669 | */ | |
2670 | bool vfs_inode_has_locks(struct inode *inode) | |
2671 | { | |
2672 | struct file_lock_context *ctx; | |
2673 | bool ret; | |
2674 | ||
401a8b8f | 2675 | ctx = locks_inode_context(inode); |
ab1ddef9 JL |
2676 | if (!ctx) |
2677 | return false; | |
2678 | ||
2679 | spin_lock(&ctx->flc_lock); | |
2680 | ret = !list_empty(&ctx->flc_posix) || !list_empty(&ctx->flc_flock); | |
2681 | spin_unlock(&ctx->flc_lock); | |
2682 | return ret; | |
2683 | } | |
2684 | EXPORT_SYMBOL_GPL(vfs_inode_has_locks); | |
2685 | ||
7f8ada98 | 2686 | #ifdef CONFIG_PROC_FS |
d8ba7a36 | 2687 | #include <linux/proc_fs.h> |
7f8ada98 PE |
2688 | #include <linux/seq_file.h> |
2689 | ||
7012b02a JL |
2690 | struct locks_iterator { |
2691 | int li_cpu; | |
2692 | loff_t li_pos; | |
2693 | }; | |
2694 | ||
7f8ada98 | 2695 | static void lock_get_status(struct seq_file *f, struct file_lock *fl, |
b8da9b10 | 2696 | loff_t id, char *pfx, int repeat) |
1da177e4 LT |
2697 | { |
2698 | struct inode *inode = NULL; | |
ab1f1611 | 2699 | unsigned int fl_pid; |
9d78edea | 2700 | struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)->i_sb); |
90f7d7a0 | 2701 | int type; |
ab1f1611 | 2702 | |
9d5b86ac BC |
2703 | fl_pid = locks_translate_pid(fl, proc_pidns); |
2704 | /* | |
1cf8e5de KK |
2705 | * If lock owner is dead (and pid is freed) or not visible in current |
2706 | * pidns, zero is shown as a pid value. Check lock info from | |
2707 | * init_pid_ns to get saved lock pid value. | |
9d5b86ac | 2708 | */ |
1da177e4 LT |
2709 | |
2710 | if (fl->fl_file != NULL) | |
c65454a9 | 2711 | inode = file_inode(fl->fl_file); |
1da177e4 | 2712 | |
b8da9b10 LL |
2713 | seq_printf(f, "%lld: ", id); |
2714 | ||
2715 | if (repeat) | |
2716 | seq_printf(f, "%*s", repeat - 1 + (int)strlen(pfx), pfx); | |
2717 | ||
1da177e4 | 2718 | if (IS_POSIX(fl)) { |
c918d42a | 2719 | if (fl->fl_flags & FL_ACCESS) |
5315c26a | 2720 | seq_puts(f, "ACCESS"); |
cff2fce5 | 2721 | else if (IS_OFDLCK(fl)) |
5315c26a | 2722 | seq_puts(f, "OFDLCK"); |
c918d42a | 2723 | else |
5315c26a | 2724 | seq_puts(f, "POSIX "); |
c918d42a JL |
2725 | |
2726 | seq_printf(f, " %s ", | |
f7e33bdb | 2727 | (inode == NULL) ? "*NOINODE*" : "ADVISORY "); |
1da177e4 | 2728 | } else if (IS_FLOCK(fl)) { |
90f7d7a0 | 2729 | seq_puts(f, "FLOCK ADVISORY "); |
1da177e4 | 2730 | } else if (IS_LEASE(fl)) { |
8144f1f6 JL |
2731 | if (fl->fl_flags & FL_DELEG) |
2732 | seq_puts(f, "DELEG "); | |
2733 | else | |
2734 | seq_puts(f, "LEASE "); | |
2735 | ||
ab83fa4b | 2736 | if (lease_breaking(fl)) |
5315c26a | 2737 | seq_puts(f, "BREAKING "); |
1da177e4 | 2738 | else if (fl->fl_file) |
5315c26a | 2739 | seq_puts(f, "ACTIVE "); |
1da177e4 | 2740 | else |
5315c26a | 2741 | seq_puts(f, "BREAKER "); |
1da177e4 | 2742 | } else { |
5315c26a | 2743 | seq_puts(f, "UNKNOWN UNKNOWN "); |
1da177e4 | 2744 | } |
90f7d7a0 | 2745 | type = IS_LEASE(fl) ? target_leasetype(fl) : fl->fl_type; |
43e4cb94 | 2746 | |
90f7d7a0 JL |
2747 | seq_printf(f, "%s ", (type == F_WRLCK) ? "WRITE" : |
2748 | (type == F_RDLCK) ? "READ" : "UNLCK"); | |
1da177e4 | 2749 | if (inode) { |
3648888e | 2750 | /* userspace relies on this representation of dev_t */ |
98ca480a | 2751 | seq_printf(f, "%d %02x:%02x:%lu ", fl_pid, |
1da177e4 LT |
2752 | MAJOR(inode->i_sb->s_dev), |
2753 | MINOR(inode->i_sb->s_dev), inode->i_ino); | |
1da177e4 | 2754 | } else { |
ab1f1611 | 2755 | seq_printf(f, "%d <none>:0 ", fl_pid); |
1da177e4 LT |
2756 | } |
2757 | if (IS_POSIX(fl)) { | |
2758 | if (fl->fl_end == OFFSET_MAX) | |
7f8ada98 | 2759 | seq_printf(f, "%Ld EOF\n", fl->fl_start); |
1da177e4 | 2760 | else |
7f8ada98 | 2761 | seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end); |
1da177e4 | 2762 | } else { |
5315c26a | 2763 | seq_puts(f, "0 EOF\n"); |
1da177e4 LT |
2764 | } |
2765 | } | |
2766 | ||
b8da9b10 LL |
2767 | static struct file_lock *get_next_blocked_member(struct file_lock *node) |
2768 | { | |
2769 | struct file_lock *tmp; | |
2770 | ||
2771 | /* NULL node or root node */ | |
2772 | if (node == NULL || node->fl_blocker == NULL) | |
2773 | return NULL; | |
2774 | ||
2775 | /* Next member in the linked list could be itself */ | |
2776 | tmp = list_next_entry(node, fl_blocked_member); | |
2777 | if (list_entry_is_head(tmp, &node->fl_blocker->fl_blocked_requests, fl_blocked_member) | |
2778 | || tmp == node) { | |
2779 | return NULL; | |
2780 | } | |
2781 | ||
2782 | return tmp; | |
2783 | } | |
2784 | ||
7f8ada98 | 2785 | static int locks_show(struct seq_file *f, void *v) |
1da177e4 | 2786 | { |
7012b02a | 2787 | struct locks_iterator *iter = f->private; |
b8da9b10 | 2788 | struct file_lock *cur, *tmp; |
9d78edea | 2789 | struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)->i_sb); |
b8da9b10 | 2790 | int level = 0; |
1da177e4 | 2791 | |
b8da9b10 | 2792 | cur = hlist_entry(v, struct file_lock, fl_link); |
1da177e4 | 2793 | |
b8da9b10 | 2794 | if (locks_translate_pid(cur, proc_pidns) == 0) |
d67fd44f NB |
2795 | return 0; |
2796 | ||
b8da9b10 LL |
2797 | /* View this crossed linked list as a binary tree, the first member of fl_blocked_requests |
2798 | * is the left child of current node, the next silibing in fl_blocked_member is the | |
2799 | * right child, we can alse get the parent of current node from fl_blocker, so this | |
2800 | * question becomes traversal of a binary tree | |
2801 | */ | |
2802 | while (cur != NULL) { | |
2803 | if (level) | |
2804 | lock_get_status(f, cur, iter->li_pos, "-> ", level); | |
2805 | else | |
2806 | lock_get_status(f, cur, iter->li_pos, "", level); | |
1da177e4 | 2807 | |
b8da9b10 LL |
2808 | if (!list_empty(&cur->fl_blocked_requests)) { |
2809 | /* Turn left */ | |
2810 | cur = list_first_entry_or_null(&cur->fl_blocked_requests, | |
2811 | struct file_lock, fl_blocked_member); | |
2812 | level++; | |
2813 | } else { | |
2814 | /* Turn right */ | |
2815 | tmp = get_next_blocked_member(cur); | |
2816 | /* Fall back to parent node */ | |
2817 | while (tmp == NULL && cur->fl_blocker != NULL) { | |
2818 | cur = cur->fl_blocker; | |
2819 | level--; | |
2820 | tmp = get_next_blocked_member(cur); | |
2821 | } | |
2822 | cur = tmp; | |
2823 | } | |
2824 | } | |
094f2825 | 2825 | |
7f8ada98 PE |
2826 | return 0; |
2827 | } | |
1da177e4 | 2828 | |
6c8c9031 AV |
2829 | static void __show_fd_locks(struct seq_file *f, |
2830 | struct list_head *head, int *id, | |
2831 | struct file *filp, struct files_struct *files) | |
2832 | { | |
2833 | struct file_lock *fl; | |
2834 | ||
2835 | list_for_each_entry(fl, head, fl_list) { | |
2836 | ||
2837 | if (filp != fl->fl_file) | |
2838 | continue; | |
2839 | if (fl->fl_owner != files && | |
2840 | fl->fl_owner != filp) | |
2841 | continue; | |
2842 | ||
2843 | (*id)++; | |
2844 | seq_puts(f, "lock:\t"); | |
b8da9b10 | 2845 | lock_get_status(f, fl, *id, "", 0); |
6c8c9031 AV |
2846 | } |
2847 | } | |
2848 | ||
2849 | void show_fd_locks(struct seq_file *f, | |
2850 | struct file *filp, struct files_struct *files) | |
2851 | { | |
c65454a9 | 2852 | struct inode *inode = file_inode(filp); |
6c8c9031 AV |
2853 | struct file_lock_context *ctx; |
2854 | int id = 0; | |
2855 | ||
401a8b8f | 2856 | ctx = locks_inode_context(inode); |
6c8c9031 AV |
2857 | if (!ctx) |
2858 | return; | |
2859 | ||
2860 | spin_lock(&ctx->flc_lock); | |
2861 | __show_fd_locks(f, &ctx->flc_flock, &id, filp, files); | |
2862 | __show_fd_locks(f, &ctx->flc_posix, &id, filp, files); | |
2863 | __show_fd_locks(f, &ctx->flc_lease, &id, filp, files); | |
2864 | spin_unlock(&ctx->flc_lock); | |
2865 | } | |
2866 | ||
7f8ada98 | 2867 | static void *locks_start(struct seq_file *f, loff_t *pos) |
b03dfdec | 2868 | __acquires(&blocked_lock_lock) |
7f8ada98 | 2869 | { |
7012b02a | 2870 | struct locks_iterator *iter = f->private; |
99dc8292 | 2871 | |
7012b02a | 2872 | iter->li_pos = *pos + 1; |
aba37660 | 2873 | percpu_down_write(&file_rwsem); |
7b2296af | 2874 | spin_lock(&blocked_lock_lock); |
7c3f654d | 2875 | return seq_hlist_start_percpu(&file_lock_list.hlist, &iter->li_cpu, *pos); |
7f8ada98 | 2876 | } |
1da177e4 | 2877 | |
7f8ada98 PE |
2878 | static void *locks_next(struct seq_file *f, void *v, loff_t *pos) |
2879 | { | |
7012b02a JL |
2880 | struct locks_iterator *iter = f->private; |
2881 | ||
2882 | ++iter->li_pos; | |
7c3f654d | 2883 | return seq_hlist_next_percpu(v, &file_lock_list.hlist, &iter->li_cpu, pos); |
7f8ada98 | 2884 | } |
1da177e4 | 2885 | |
7f8ada98 | 2886 | static void locks_stop(struct seq_file *f, void *v) |
b03dfdec | 2887 | __releases(&blocked_lock_lock) |
7f8ada98 | 2888 | { |
7b2296af | 2889 | spin_unlock(&blocked_lock_lock); |
aba37660 | 2890 | percpu_up_write(&file_rwsem); |
1da177e4 LT |
2891 | } |
2892 | ||
d8ba7a36 | 2893 | static const struct seq_operations locks_seq_operations = { |
7f8ada98 PE |
2894 | .start = locks_start, |
2895 | .next = locks_next, | |
2896 | .stop = locks_stop, | |
2897 | .show = locks_show, | |
2898 | }; | |
d8ba7a36 | 2899 | |
d8ba7a36 AD |
2900 | static int __init proc_locks_init(void) |
2901 | { | |
44414d82 CH |
2902 | proc_create_seq_private("locks", 0, NULL, &locks_seq_operations, |
2903 | sizeof(struct locks_iterator), NULL); | |
d8ba7a36 AD |
2904 | return 0; |
2905 | } | |
91899226 | 2906 | fs_initcall(proc_locks_init); |
7f8ada98 PE |
2907 | #endif |
2908 | ||
1da177e4 LT |
2909 | static int __init filelock_init(void) |
2910 | { | |
7012b02a JL |
2911 | int i; |
2912 | ||
4a075e39 | 2913 | flctx_cache = kmem_cache_create("file_lock_ctx", |
3754707b | 2914 | sizeof(struct file_lock_context), 0, SLAB_PANIC, NULL); |
4a075e39 | 2915 | |
1da177e4 | 2916 | filelock_cache = kmem_cache_create("file_lock_cache", |
3754707b | 2917 | sizeof(struct file_lock), 0, SLAB_PANIC, NULL); |
ee19cc40 | 2918 | |
7c3f654d PZ |
2919 | for_each_possible_cpu(i) { |
2920 | struct file_lock_list_struct *fll = per_cpu_ptr(&file_lock_list, i); | |
2921 | ||
2922 | spin_lock_init(&fll->lock); | |
2923 | INIT_HLIST_HEAD(&fll->hlist); | |
2924 | } | |
7012b02a | 2925 | |
18f6622e | 2926 | lease_notifier_chain_init(); |
1da177e4 LT |
2927 | return 0; |
2928 | } | |
1da177e4 | 2929 | core_initcall(filelock_init); |