1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/ceph/ceph_debug.h>
3
4 #include <linux/file.h>
5 #include <linux/namei.h>
6 #include <linux/random.h>
7
8 #include "super.h"
9 #include "mds_client.h"
10 #include <linux/filelock.h>
11 #include <linux/ceph/pagelist.h>
12
13 static u64 lock_secret;
14 static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc,
15 struct ceph_mds_request *req);
16
secure_addr(void * addr)17 static inline u64 secure_addr(void *addr)
18 {
19 u64 v = lock_secret ^ (u64)(unsigned long)addr;
20 /*
21 * Set the most significant bit, so that MDS knows the 'owner'
22 * is sufficient to identify the owner of lock. (old code uses
23 * both 'owner' and 'pid')
24 */
25 v |= (1ULL << 63);
26 return v;
27 }
28
ceph_flock_init(void)29 void __init ceph_flock_init(void)
30 {
31 get_random_bytes(&lock_secret, sizeof(lock_secret));
32 }
33
ceph_fl_copy_lock(struct file_lock * dst,struct file_lock * src)34 static void ceph_fl_copy_lock(struct file_lock *dst, struct file_lock *src)
35 {
36 struct inode *inode = file_inode(dst->c.flc_file);
37 atomic_inc(&ceph_inode(inode)->i_filelock_ref);
38 dst->fl_u.ceph.inode = igrab(inode);
39 }
40
41 /*
42 * Do not use the 'fl->fl_file' in release function, which
43 * is possibly already released by another thread.
44 */
ceph_fl_release_lock(struct file_lock * fl)45 static void ceph_fl_release_lock(struct file_lock *fl)
46 {
47 struct inode *inode = fl->fl_u.ceph.inode;
48 struct ceph_inode_info *ci;
49
50 /*
51 * If inode is NULL it should be a request file_lock,
52 * nothing we can do.
53 */
54 if (!inode)
55 return;
56
57 ci = ceph_inode(inode);
58 if (atomic_dec_and_test(&ci->i_filelock_ref)) {
59 /* clear error when all locks are released */
60 spin_lock(&ci->i_ceph_lock);
61 ci->i_ceph_flags &= ~CEPH_I_ERROR_FILELOCK;
62 spin_unlock(&ci->i_ceph_lock);
63 }
64 fl->fl_u.ceph.inode = NULL;
65 iput(inode);
66 }
67
68 static const struct file_lock_operations ceph_fl_lock_ops = {
69 .fl_copy_lock = ceph_fl_copy_lock,
70 .fl_release_private = ceph_fl_release_lock,
71 };
72
73 /*
74 * Implement fcntl and flock locking functions.
75 */
ceph_lock_message(u8 lock_type,u16 operation,struct inode * inode,int cmd,u8 wait,struct file_lock * fl)76 static int ceph_lock_message(u8 lock_type, u16 operation, struct inode *inode,
77 int cmd, u8 wait, struct file_lock *fl)
78 {
79 struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
80 struct ceph_client *cl = mdsc->fsc->client;
81 struct ceph_mds_request *req;
82 int err;
83 u64 length = 0;
84 u64 owner;
85
86 if (operation == CEPH_MDS_OP_SETFILELOCK) {
87 /*
88 * increasing i_filelock_ref closes race window between
89 * handling request reply and adding file_lock struct to
90 * inode. Otherwise, auth caps may get trimmed in the
91 * window. Caller function will decrease the counter.
92 */
93 fl->fl_ops = &ceph_fl_lock_ops;
94 fl->fl_ops->fl_copy_lock(fl, NULL);
95 }
96
97 if (operation != CEPH_MDS_OP_SETFILELOCK || cmd == CEPH_LOCK_UNLOCK)
98 wait = 0;
99
100 req = ceph_mdsc_create_request(mdsc, operation, USE_AUTH_MDS);
101 if (IS_ERR(req))
102 return PTR_ERR(req);
103 req->r_inode = inode;
104 ihold(inode);
105 req->r_num_caps = 1;
106
107 /* mds requires start and length rather than start and end */
108 if (LLONG_MAX == fl->fl_end)
109 length = 0;
110 else
111 length = fl->fl_end - fl->fl_start + 1;
112
113 owner = secure_addr(fl->c.flc_owner);
114
115 doutc(cl, "rule: %d, op: %d, owner: %llx, pid: %llu, "
116 "start: %llu, length: %llu, wait: %d, type: %d\n",
117 (int)lock_type, (int)operation, owner,
118 (u64) fl->c.flc_pid,
119 fl->fl_start, length, wait, fl->c.flc_type);
120
121 req->r_args.filelock_change.rule = lock_type;
122 req->r_args.filelock_change.type = cmd;
123 req->r_args.filelock_change.owner = cpu_to_le64(owner);
124 req->r_args.filelock_change.pid = cpu_to_le64((u64) fl->c.flc_pid);
125 req->r_args.filelock_change.start = cpu_to_le64(fl->fl_start);
126 req->r_args.filelock_change.length = cpu_to_le64(length);
127 req->r_args.filelock_change.wait = wait;
128
129 err = ceph_mdsc_submit_request(mdsc, inode, req);
130 if (!err)
131 err = ceph_mdsc_wait_request(mdsc, req, wait ?
132 ceph_lock_wait_for_completion : NULL);
133 if (!err && operation == CEPH_MDS_OP_GETFILELOCK) {
134 fl->c.flc_pid = -le64_to_cpu(req->r_reply_info.filelock_reply->pid);
135 if (CEPH_LOCK_SHARED == req->r_reply_info.filelock_reply->type)
136 fl->c.flc_type = F_RDLCK;
137 else if (CEPH_LOCK_EXCL == req->r_reply_info.filelock_reply->type)
138 fl->c.flc_type = F_WRLCK;
139 else
140 fl->c.flc_type = F_UNLCK;
141
142 fl->fl_start = le64_to_cpu(req->r_reply_info.filelock_reply->start);
143 length = le64_to_cpu(req->r_reply_info.filelock_reply->start) +
144 le64_to_cpu(req->r_reply_info.filelock_reply->length);
145 if (length >= 1)
146 fl->fl_end = length -1;
147 else
148 fl->fl_end = 0;
149
150 }
151 ceph_mdsc_put_request(req);
152 doutc(cl, "rule: %d, op: %d, pid: %llu, start: %llu, "
153 "length: %llu, wait: %d, type: %d, err code %d\n",
154 (int)lock_type, (int)operation, (u64) fl->c.flc_pid,
155 fl->fl_start, length, wait, fl->c.flc_type, err);
156 return err;
157 }
158
ceph_lock_wait_for_completion(struct ceph_mds_client * mdsc,struct ceph_mds_request * req)159 static int ceph_lock_wait_for_completion(struct ceph_mds_client *mdsc,
160 struct ceph_mds_request *req)
161 {
162 struct ceph_client *cl = mdsc->fsc->client;
163 struct ceph_mds_request *intr_req;
164 struct inode *inode = req->r_inode;
165 int err, lock_type;
166
167 BUG_ON(req->r_op != CEPH_MDS_OP_SETFILELOCK);
168 if (req->r_args.filelock_change.rule == CEPH_LOCK_FCNTL)
169 lock_type = CEPH_LOCK_FCNTL_INTR;
170 else if (req->r_args.filelock_change.rule == CEPH_LOCK_FLOCK)
171 lock_type = CEPH_LOCK_FLOCK_INTR;
172 else
173 BUG_ON(1);
174 BUG_ON(req->r_args.filelock_change.type == CEPH_LOCK_UNLOCK);
175
176 err = wait_for_completion_interruptible(&req->r_completion);
177 if (!err)
178 return 0;
179
180 doutc(cl, "request %llu was interrupted\n", req->r_tid);
181
182 mutex_lock(&mdsc->mutex);
183 if (test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags)) {
184 err = 0;
185 } else {
186 /*
187 * ensure we aren't running concurrently with
188 * ceph_fill_trace or ceph_readdir_prepopulate, which
189 * rely on locks (dir mutex) held by our caller.
190 */
191 mutex_lock(&req->r_fill_mutex);
192 req->r_err = err;
193 set_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags);
194 mutex_unlock(&req->r_fill_mutex);
195
196 if (!req->r_session) {
197 // haven't sent the request
198 err = 0;
199 }
200 }
201 mutex_unlock(&mdsc->mutex);
202 if (!err)
203 return 0;
204
205 intr_req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_SETFILELOCK,
206 USE_AUTH_MDS);
207 if (IS_ERR(intr_req))
208 return PTR_ERR(intr_req);
209
210 intr_req->r_inode = inode;
211 ihold(inode);
212 intr_req->r_num_caps = 1;
213
214 intr_req->r_args.filelock_change = req->r_args.filelock_change;
215 intr_req->r_args.filelock_change.rule = lock_type;
216 intr_req->r_args.filelock_change.type = CEPH_LOCK_UNLOCK;
217
218 err = ceph_mdsc_do_request(mdsc, inode, intr_req);
219 ceph_mdsc_put_request(intr_req);
220
221 if (err && err != -ERESTARTSYS)
222 return err;
223
224 wait_for_completion_killable(&req->r_safe_completion);
225 return 0;
226 }
227
try_unlock_file(struct file * file,struct file_lock * fl)228 static int try_unlock_file(struct file *file, struct file_lock *fl)
229 {
230 int err;
231 unsigned int orig_flags = fl->c.flc_flags;
232 fl->c.flc_flags |= FL_EXISTS;
233 err = locks_lock_file_wait(file, fl);
234 fl->c.flc_flags = orig_flags;
235 if (err == -ENOENT) {
236 if (!(orig_flags & FL_EXISTS))
237 err = 0;
238 return err;
239 }
240 return 1;
241 }
242
243 /*
244 * Attempt to set an fcntl lock.
245 * For now, this just goes away to the server. Later it may be more awesome.
246 */
ceph_lock(struct file * file,int cmd,struct file_lock * fl)247 int ceph_lock(struct file *file, int cmd, struct file_lock *fl)
248 {
249 struct inode *inode = file_inode(file);
250 struct ceph_inode_info *ci = ceph_inode(inode);
251 struct ceph_client *cl = ceph_inode_to_client(inode);
252 int err = 0;
253 u16 op = CEPH_MDS_OP_SETFILELOCK;
254 u8 wait = 0;
255 u8 lock_cmd;
256
257 if (!(fl->c.flc_flags & FL_POSIX))
258 return -ENOLCK;
259
260 if (ceph_inode_is_shutdown(inode))
261 return -ESTALE;
262
263 doutc(cl, "fl_owner: %p\n", fl->c.flc_owner);
264
265 /* set wait bit as appropriate, then make command as Ceph expects it*/
266 if (IS_GETLK(cmd))
267 op = CEPH_MDS_OP_GETFILELOCK;
268 else if (IS_SETLKW(cmd))
269 wait = 1;
270
271 spin_lock(&ci->i_ceph_lock);
272 if (ci->i_ceph_flags & CEPH_I_ERROR_FILELOCK) {
273 err = -EIO;
274 }
275 spin_unlock(&ci->i_ceph_lock);
276 if (err < 0) {
277 if (op == CEPH_MDS_OP_SETFILELOCK && lock_is_unlock(fl))
278 posix_lock_file(file, fl, NULL);
279 return err;
280 }
281
282 if (lock_is_read(fl))
283 lock_cmd = CEPH_LOCK_SHARED;
284 else if (lock_is_write(fl))
285 lock_cmd = CEPH_LOCK_EXCL;
286 else
287 lock_cmd = CEPH_LOCK_UNLOCK;
288
289 if (op == CEPH_MDS_OP_SETFILELOCK && lock_is_unlock(fl)) {
290 err = try_unlock_file(file, fl);
291 if (err <= 0)
292 return err;
293 }
294
295 err = ceph_lock_message(CEPH_LOCK_FCNTL, op, inode, lock_cmd, wait, fl);
296 if (!err) {
297 if (op == CEPH_MDS_OP_SETFILELOCK && F_UNLCK != fl->c.flc_type) {
298 doutc(cl, "locking locally\n");
299 err = posix_lock_file(file, fl, NULL);
300 if (err) {
301 /* undo! This should only happen if
302 * the kernel detects local
303 * deadlock. */
304 ceph_lock_message(CEPH_LOCK_FCNTL, op, inode,
305 CEPH_LOCK_UNLOCK, 0, fl);
306 doutc(cl, "got %d on posix_lock_file, undid lock\n",
307 err);
308 }
309 }
310 }
311 return err;
312 }
313
ceph_flock(struct file * file,int cmd,struct file_lock * fl)314 int ceph_flock(struct file *file, int cmd, struct file_lock *fl)
315 {
316 struct inode *inode = file_inode(file);
317 struct ceph_inode_info *ci = ceph_inode(inode);
318 struct ceph_client *cl = ceph_inode_to_client(inode);
319 int err = 0;
320 u8 wait = 0;
321 u8 lock_cmd;
322
323 if (!(fl->c.flc_flags & FL_FLOCK))
324 return -ENOLCK;
325
326 if (ceph_inode_is_shutdown(inode))
327 return -ESTALE;
328
329 doutc(cl, "fl_file: %p\n", fl->c.flc_file);
330
331 spin_lock(&ci->i_ceph_lock);
332 if (ci->i_ceph_flags & CEPH_I_ERROR_FILELOCK) {
333 err = -EIO;
334 }
335 spin_unlock(&ci->i_ceph_lock);
336 if (err < 0) {
337 if (lock_is_unlock(fl))
338 locks_lock_file_wait(file, fl);
339 return err;
340 }
341
342 if (IS_SETLKW(cmd))
343 wait = 1;
344
345 if (lock_is_read(fl))
346 lock_cmd = CEPH_LOCK_SHARED;
347 else if (lock_is_write(fl))
348 lock_cmd = CEPH_LOCK_EXCL;
349 else
350 lock_cmd = CEPH_LOCK_UNLOCK;
351
352 if (lock_is_unlock(fl)) {
353 err = try_unlock_file(file, fl);
354 if (err <= 0)
355 return err;
356 }
357
358 err = ceph_lock_message(CEPH_LOCK_FLOCK, CEPH_MDS_OP_SETFILELOCK,
359 inode, lock_cmd, wait, fl);
360 if (!err && F_UNLCK != fl->c.flc_type) {
361 err = locks_lock_file_wait(file, fl);
362 if (err) {
363 ceph_lock_message(CEPH_LOCK_FLOCK,
364 CEPH_MDS_OP_SETFILELOCK,
365 inode, CEPH_LOCK_UNLOCK, 0, fl);
366 doutc(cl, "got %d on locks_lock_file_wait, undid lock\n",
367 err);
368 }
369 }
370 return err;
371 }
372
373 /*
374 * Fills in the passed counter variables, so you can prepare pagelist metadata
375 * before calling ceph_encode_locks.
376 */
ceph_count_locks(struct inode * inode,int * fcntl_count,int * flock_count)377 void ceph_count_locks(struct inode *inode, int *fcntl_count, int *flock_count)
378 {
379 struct ceph_client *cl = ceph_inode_to_client(inode);
380 struct file_lock *lock;
381 struct file_lock_context *ctx;
382
383 *fcntl_count = 0;
384 *flock_count = 0;
385
386 ctx = locks_inode_context(inode);
387 if (ctx) {
388 spin_lock(&ctx->flc_lock);
389 for_each_file_lock(lock, &ctx->flc_posix)
390 ++(*fcntl_count);
391 for_each_file_lock(lock, &ctx->flc_flock)
392 ++(*flock_count);
393 spin_unlock(&ctx->flc_lock);
394 }
395 doutc(cl, "counted %d flock locks and %d fcntl locks\n",
396 *flock_count, *fcntl_count);
397 }
398
399 /*
400 * Given a pointer to a lock, convert it to a ceph filelock
401 */
lock_to_ceph_filelock(struct inode * inode,struct file_lock * lock,struct ceph_filelock * cephlock)402 static int lock_to_ceph_filelock(struct inode *inode,
403 struct file_lock *lock,
404 struct ceph_filelock *cephlock)
405 {
406 struct ceph_client *cl = ceph_inode_to_client(inode);
407 int err = 0;
408
409 cephlock->start = cpu_to_le64(lock->fl_start);
410 cephlock->length = cpu_to_le64(lock->fl_end - lock->fl_start + 1);
411 cephlock->client = cpu_to_le64(0);
412 cephlock->pid = cpu_to_le64((u64) lock->c.flc_pid);
413 cephlock->owner = cpu_to_le64(secure_addr(lock->c.flc_owner));
414
415 switch (lock->c.flc_type) {
416 case F_RDLCK:
417 cephlock->type = CEPH_LOCK_SHARED;
418 break;
419 case F_WRLCK:
420 cephlock->type = CEPH_LOCK_EXCL;
421 break;
422 case F_UNLCK:
423 cephlock->type = CEPH_LOCK_UNLOCK;
424 break;
425 default:
426 doutc(cl, "Have unknown lock type %d\n",
427 lock->c.flc_type);
428 err = -EINVAL;
429 }
430
431 return err;
432 }
433
434 /*
435 * Encode the flock and fcntl locks for the given inode into the ceph_filelock
436 * array. Must be called with inode->i_lock already held.
437 * If we encounter more of a specific lock type than expected, return -ENOSPC.
438 */
ceph_encode_locks_to_buffer(struct inode * inode,struct ceph_filelock * flocks,int num_fcntl_locks,int num_flock_locks)439 int ceph_encode_locks_to_buffer(struct inode *inode,
440 struct ceph_filelock *flocks,
441 int num_fcntl_locks, int num_flock_locks)
442 {
443 struct file_lock *lock;
444 struct file_lock_context *ctx = locks_inode_context(inode);
445 struct ceph_client *cl = ceph_inode_to_client(inode);
446 int err = 0;
447 int seen_fcntl = 0;
448 int seen_flock = 0;
449 int l = 0;
450
451 doutc(cl, "encoding %d flock and %d fcntl locks\n", num_flock_locks,
452 num_fcntl_locks);
453
454 if (!ctx)
455 return 0;
456
457 spin_lock(&ctx->flc_lock);
458 for_each_file_lock(lock, &ctx->flc_posix) {
459 ++seen_fcntl;
460 if (seen_fcntl > num_fcntl_locks) {
461 err = -ENOSPC;
462 goto fail;
463 }
464 err = lock_to_ceph_filelock(inode, lock, &flocks[l]);
465 if (err)
466 goto fail;
467 ++l;
468 }
469 for_each_file_lock(lock, &ctx->flc_flock) {
470 ++seen_flock;
471 if (seen_flock > num_flock_locks) {
472 err = -ENOSPC;
473 goto fail;
474 }
475 err = lock_to_ceph_filelock(inode, lock, &flocks[l]);
476 if (err)
477 goto fail;
478 ++l;
479 }
480 fail:
481 spin_unlock(&ctx->flc_lock);
482 return err;
483 }
484
485 /*
486 * Copy the encoded flock and fcntl locks into the pagelist.
487 * Format is: #fcntl locks, sequential fcntl locks, #flock locks,
488 * sequential flock locks.
489 * Returns zero on success.
490 */
ceph_locks_to_pagelist(struct ceph_filelock * flocks,struct ceph_pagelist * pagelist,int num_fcntl_locks,int num_flock_locks)491 int ceph_locks_to_pagelist(struct ceph_filelock *flocks,
492 struct ceph_pagelist *pagelist,
493 int num_fcntl_locks, int num_flock_locks)
494 {
495 int err = 0;
496 __le32 nlocks;
497
498 nlocks = cpu_to_le32(num_fcntl_locks);
499 err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks));
500 if (err)
501 goto out_fail;
502
503 if (num_fcntl_locks > 0) {
504 err = ceph_pagelist_append(pagelist, flocks,
505 num_fcntl_locks * sizeof(*flocks));
506 if (err)
507 goto out_fail;
508 }
509
510 nlocks = cpu_to_le32(num_flock_locks);
511 err = ceph_pagelist_append(pagelist, &nlocks, sizeof(nlocks));
512 if (err)
513 goto out_fail;
514
515 if (num_flock_locks > 0) {
516 err = ceph_pagelist_append(pagelist, &flocks[num_fcntl_locks],
517 num_flock_locks * sizeof(*flocks));
518 }
519 out_fail:
520 return err;
521 }
522