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