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