xref: /linux/fs/ceph/mds_client.c (revision 409c38d4f156740bf3165fd6ceae4fa6425eebf4)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/ceph/ceph_debug.h>
3 
4 #include <linux/fs.h>
5 #include <linux/wait.h>
6 #include <linux/slab.h>
7 #include <linux/gfp.h>
8 #include <linux/sched.h>
9 #include <linux/debugfs.h>
10 #include <linux/seq_file.h>
11 #include <linux/ratelimit.h>
12 #include <linux/bits.h>
13 #include <linux/ktime.h>
14 #include <linux/bitmap.h>
15 #include <linux/mnt_idmapping.h>
16 
17 #include "super.h"
18 #include "mds_client.h"
19 #include "crypto.h"
20 
21 #include <linux/ceph/ceph_features.h>
22 #include <linux/ceph/messenger.h>
23 #include <linux/ceph/decode.h>
24 #include <linux/ceph/pagelist.h>
25 #include <linux/ceph/auth.h>
26 #include <linux/ceph/debugfs.h>
27 
28 #define RECONNECT_MAX_SIZE (INT_MAX - PAGE_SIZE)
29 
30 /*
31  * A cluster of MDS (metadata server) daemons is responsible for
32  * managing the file system namespace (the directory hierarchy and
33  * inodes) and for coordinating shared access to storage.  Metadata is
34  * partitioning hierarchically across a number of servers, and that
35  * partition varies over time as the cluster adjusts the distribution
36  * in order to balance load.
37  *
38  * The MDS client is primarily responsible to managing synchronous
39  * metadata requests for operations like open, unlink, and so forth.
40  * If there is a MDS failure, we find out about it when we (possibly
41  * request and) receive a new MDS map, and can resubmit affected
42  * requests.
43  *
44  * For the most part, though, we take advantage of a lossless
45  * communications channel to the MDS, and do not need to worry about
46  * timing out or resubmitting requests.
47  *
48  * We maintain a stateful "session" with each MDS we interact with.
49  * Within each session, we sent periodic heartbeat messages to ensure
50  * any capabilities or leases we have been issues remain valid.  If
51  * the session times out and goes stale, our leases and capabilities
52  * are no longer valid.
53  */
54 
55 struct ceph_reconnect_state {
56 	struct ceph_mds_session *session;
57 	int nr_caps, nr_realms;
58 	struct ceph_pagelist *pagelist;
59 	unsigned msg_version;
60 	bool allow_multi;
61 };
62 
63 static void __wake_requests(struct ceph_mds_client *mdsc,
64 			    struct list_head *head);
65 static void ceph_cap_release_work(struct work_struct *work);
66 static void ceph_cap_reclaim_work(struct work_struct *work);
67 
68 static const struct ceph_connection_operations mds_con_ops;
69 
70 
71 /*
72  * mds reply parsing
73  */
74 
75 static int parse_reply_info_quota(void **p, void *end,
76 				  struct ceph_mds_reply_info_in *info)
77 {
78 	u8 struct_v, struct_compat;
79 	u32 struct_len;
80 
81 	ceph_decode_8_safe(p, end, struct_v, bad);
82 	ceph_decode_8_safe(p, end, struct_compat, bad);
83 	/* struct_v is expected to be >= 1. we only
84 	 * understand encoding with struct_compat == 1. */
85 	if (!struct_v || struct_compat != 1)
86 		goto bad;
87 	ceph_decode_32_safe(p, end, struct_len, bad);
88 	ceph_decode_need(p, end, struct_len, bad);
89 	end = *p + struct_len;
90 	ceph_decode_64_safe(p, end, info->max_bytes, bad);
91 	ceph_decode_64_safe(p, end, info->max_files, bad);
92 	*p = end;
93 	return 0;
94 bad:
95 	return -EIO;
96 }
97 
98 /*
99  * parse individual inode info
100  */
101 static int parse_reply_info_in(void **p, void *end,
102 			       struct ceph_mds_reply_info_in *info,
103 			       u64 features)
104 {
105 	int err = 0;
106 	u8 struct_v = 0;
107 
108 	if (features == (u64)-1) {
109 		u32 struct_len;
110 		u8 struct_compat;
111 		ceph_decode_8_safe(p, end, struct_v, bad);
112 		ceph_decode_8_safe(p, end, struct_compat, bad);
113 		/* struct_v is expected to be >= 1. we only understand
114 		 * encoding with struct_compat == 1. */
115 		if (!struct_v || struct_compat != 1)
116 			goto bad;
117 		ceph_decode_32_safe(p, end, struct_len, bad);
118 		ceph_decode_need(p, end, struct_len, bad);
119 		end = *p + struct_len;
120 	}
121 
122 	ceph_decode_need(p, end, sizeof(struct ceph_mds_reply_inode), bad);
123 	info->in = *p;
124 	*p += sizeof(struct ceph_mds_reply_inode) +
125 		sizeof(*info->in->fragtree.splits) *
126 		le32_to_cpu(info->in->fragtree.nsplits);
127 
128 	ceph_decode_32_safe(p, end, info->symlink_len, bad);
129 	ceph_decode_need(p, end, info->symlink_len, bad);
130 	info->symlink = *p;
131 	*p += info->symlink_len;
132 
133 	ceph_decode_copy_safe(p, end, &info->dir_layout,
134 			      sizeof(info->dir_layout), bad);
135 	ceph_decode_32_safe(p, end, info->xattr_len, bad);
136 	ceph_decode_need(p, end, info->xattr_len, bad);
137 	info->xattr_data = *p;
138 	*p += info->xattr_len;
139 
140 	if (features == (u64)-1) {
141 		/* inline data */
142 		ceph_decode_64_safe(p, end, info->inline_version, bad);
143 		ceph_decode_32_safe(p, end, info->inline_len, bad);
144 		ceph_decode_need(p, end, info->inline_len, bad);
145 		info->inline_data = *p;
146 		*p += info->inline_len;
147 		/* quota */
148 		err = parse_reply_info_quota(p, end, info);
149 		if (err < 0)
150 			goto out_bad;
151 		/* pool namespace */
152 		ceph_decode_32_safe(p, end, info->pool_ns_len, bad);
153 		if (info->pool_ns_len > 0) {
154 			ceph_decode_need(p, end, info->pool_ns_len, bad);
155 			info->pool_ns_data = *p;
156 			*p += info->pool_ns_len;
157 		}
158 
159 		/* btime */
160 		ceph_decode_need(p, end, sizeof(info->btime), bad);
161 		ceph_decode_copy(p, &info->btime, sizeof(info->btime));
162 
163 		/* change attribute */
164 		ceph_decode_64_safe(p, end, info->change_attr, bad);
165 
166 		/* dir pin */
167 		if (struct_v >= 2) {
168 			ceph_decode_32_safe(p, end, info->dir_pin, bad);
169 		} else {
170 			info->dir_pin = -ENODATA;
171 		}
172 
173 		/* snapshot birth time, remains zero for v<=2 */
174 		if (struct_v >= 3) {
175 			ceph_decode_need(p, end, sizeof(info->snap_btime), bad);
176 			ceph_decode_copy(p, &info->snap_btime,
177 					 sizeof(info->snap_btime));
178 		} else {
179 			memset(&info->snap_btime, 0, sizeof(info->snap_btime));
180 		}
181 
182 		/* snapshot count, remains zero for v<=3 */
183 		if (struct_v >= 4) {
184 			ceph_decode_64_safe(p, end, info->rsnaps, bad);
185 		} else {
186 			info->rsnaps = 0;
187 		}
188 
189 		if (struct_v >= 5) {
190 			u32 alen;
191 
192 			ceph_decode_32_safe(p, end, alen, bad);
193 
194 			while (alen--) {
195 				u32 len;
196 
197 				/* key */
198 				ceph_decode_32_safe(p, end, len, bad);
199 				ceph_decode_skip_n(p, end, len, bad);
200 				/* value */
201 				ceph_decode_32_safe(p, end, len, bad);
202 				ceph_decode_skip_n(p, end, len, bad);
203 			}
204 		}
205 
206 		/* fscrypt flag -- ignore */
207 		if (struct_v >= 6)
208 			ceph_decode_skip_8(p, end, bad);
209 
210 		info->fscrypt_auth = NULL;
211 		info->fscrypt_auth_len = 0;
212 		info->fscrypt_file = NULL;
213 		info->fscrypt_file_len = 0;
214 		if (struct_v >= 7) {
215 			ceph_decode_32_safe(p, end, info->fscrypt_auth_len, bad);
216 			if (info->fscrypt_auth_len) {
217 				info->fscrypt_auth = kmalloc(info->fscrypt_auth_len,
218 							     GFP_KERNEL);
219 				if (!info->fscrypt_auth)
220 					return -ENOMEM;
221 				ceph_decode_copy_safe(p, end, info->fscrypt_auth,
222 						      info->fscrypt_auth_len, bad);
223 			}
224 			ceph_decode_32_safe(p, end, info->fscrypt_file_len, bad);
225 			if (info->fscrypt_file_len) {
226 				info->fscrypt_file = kmalloc(info->fscrypt_file_len,
227 							     GFP_KERNEL);
228 				if (!info->fscrypt_file)
229 					return -ENOMEM;
230 				ceph_decode_copy_safe(p, end, info->fscrypt_file,
231 						      info->fscrypt_file_len, bad);
232 			}
233 		}
234 		*p = end;
235 	} else {
236 		/* legacy (unversioned) struct */
237 		if (features & CEPH_FEATURE_MDS_INLINE_DATA) {
238 			ceph_decode_64_safe(p, end, info->inline_version, bad);
239 			ceph_decode_32_safe(p, end, info->inline_len, bad);
240 			ceph_decode_need(p, end, info->inline_len, bad);
241 			info->inline_data = *p;
242 			*p += info->inline_len;
243 		} else
244 			info->inline_version = CEPH_INLINE_NONE;
245 
246 		if (features & CEPH_FEATURE_MDS_QUOTA) {
247 			err = parse_reply_info_quota(p, end, info);
248 			if (err < 0)
249 				goto out_bad;
250 		} else {
251 			info->max_bytes = 0;
252 			info->max_files = 0;
253 		}
254 
255 		info->pool_ns_len = 0;
256 		info->pool_ns_data = NULL;
257 		if (features & CEPH_FEATURE_FS_FILE_LAYOUT_V2) {
258 			ceph_decode_32_safe(p, end, info->pool_ns_len, bad);
259 			if (info->pool_ns_len > 0) {
260 				ceph_decode_need(p, end, info->pool_ns_len, bad);
261 				info->pool_ns_data = *p;
262 				*p += info->pool_ns_len;
263 			}
264 		}
265 
266 		if (features & CEPH_FEATURE_FS_BTIME) {
267 			ceph_decode_need(p, end, sizeof(info->btime), bad);
268 			ceph_decode_copy(p, &info->btime, sizeof(info->btime));
269 			ceph_decode_64_safe(p, end, info->change_attr, bad);
270 		}
271 
272 		info->dir_pin = -ENODATA;
273 		/* info->snap_btime and info->rsnaps remain zero */
274 	}
275 	return 0;
276 bad:
277 	err = -EIO;
278 out_bad:
279 	return err;
280 }
281 
282 static int parse_reply_info_dir(void **p, void *end,
283 				struct ceph_mds_reply_dirfrag **dirfrag,
284 				u64 features)
285 {
286 	if (features == (u64)-1) {
287 		u8 struct_v, struct_compat;
288 		u32 struct_len;
289 		ceph_decode_8_safe(p, end, struct_v, bad);
290 		ceph_decode_8_safe(p, end, struct_compat, bad);
291 		/* struct_v is expected to be >= 1. we only understand
292 		 * encoding whose struct_compat == 1. */
293 		if (!struct_v || struct_compat != 1)
294 			goto bad;
295 		ceph_decode_32_safe(p, end, struct_len, bad);
296 		ceph_decode_need(p, end, struct_len, bad);
297 		end = *p + struct_len;
298 	}
299 
300 	ceph_decode_need(p, end, sizeof(**dirfrag), bad);
301 	*dirfrag = *p;
302 	*p += sizeof(**dirfrag) + sizeof(u32) * le32_to_cpu((*dirfrag)->ndist);
303 	if (unlikely(*p > end))
304 		goto bad;
305 	if (features == (u64)-1)
306 		*p = end;
307 	return 0;
308 bad:
309 	return -EIO;
310 }
311 
312 static int parse_reply_info_lease(void **p, void *end,
313 				  struct ceph_mds_reply_lease **lease,
314 				  u64 features, u32 *altname_len, u8 **altname)
315 {
316 	u8 struct_v;
317 	u32 struct_len;
318 	void *lend;
319 
320 	if (features == (u64)-1) {
321 		u8 struct_compat;
322 
323 		ceph_decode_8_safe(p, end, struct_v, bad);
324 		ceph_decode_8_safe(p, end, struct_compat, bad);
325 
326 		/* struct_v is expected to be >= 1. we only understand
327 		 * encoding whose struct_compat == 1. */
328 		if (!struct_v || struct_compat != 1)
329 			goto bad;
330 
331 		ceph_decode_32_safe(p, end, struct_len, bad);
332 	} else {
333 		struct_len = sizeof(**lease);
334 		*altname_len = 0;
335 		*altname = NULL;
336 	}
337 
338 	lend = *p + struct_len;
339 	ceph_decode_need(p, end, struct_len, bad);
340 	*lease = *p;
341 	*p += sizeof(**lease);
342 
343 	if (features == (u64)-1) {
344 		if (struct_v >= 2) {
345 			ceph_decode_32_safe(p, end, *altname_len, bad);
346 			ceph_decode_need(p, end, *altname_len, bad);
347 			*altname = *p;
348 			*p += *altname_len;
349 		} else {
350 			*altname = NULL;
351 			*altname_len = 0;
352 		}
353 	}
354 	*p = lend;
355 	return 0;
356 bad:
357 	return -EIO;
358 }
359 
360 /*
361  * parse a normal reply, which may contain a (dir+)dentry and/or a
362  * target inode.
363  */
364 static int parse_reply_info_trace(void **p, void *end,
365 				  struct ceph_mds_reply_info_parsed *info,
366 				  u64 features)
367 {
368 	int err;
369 
370 	if (info->head->is_dentry) {
371 		err = parse_reply_info_in(p, end, &info->diri, features);
372 		if (err < 0)
373 			goto out_bad;
374 
375 		err = parse_reply_info_dir(p, end, &info->dirfrag, features);
376 		if (err < 0)
377 			goto out_bad;
378 
379 		ceph_decode_32_safe(p, end, info->dname_len, bad);
380 		ceph_decode_need(p, end, info->dname_len, bad);
381 		info->dname = *p;
382 		*p += info->dname_len;
383 
384 		err = parse_reply_info_lease(p, end, &info->dlease, features,
385 					     &info->altname_len, &info->altname);
386 		if (err < 0)
387 			goto out_bad;
388 	}
389 
390 	if (info->head->is_target) {
391 		err = parse_reply_info_in(p, end, &info->targeti, features);
392 		if (err < 0)
393 			goto out_bad;
394 	}
395 
396 	if (unlikely(*p != end))
397 		goto bad;
398 	return 0;
399 
400 bad:
401 	err = -EIO;
402 out_bad:
403 	pr_err("problem parsing mds trace %d\n", err);
404 	return err;
405 }
406 
407 /*
408  * parse readdir results
409  */
410 static int parse_reply_info_readdir(void **p, void *end,
411 				    struct ceph_mds_request *req,
412 				    u64 features)
413 {
414 	struct ceph_mds_reply_info_parsed *info = &req->r_reply_info;
415 	struct ceph_client *cl = req->r_mdsc->fsc->client;
416 	u32 num, i = 0;
417 	int err;
418 
419 	err = parse_reply_info_dir(p, end, &info->dir_dir, features);
420 	if (err < 0)
421 		goto out_bad;
422 
423 	ceph_decode_need(p, end, sizeof(num) + 2, bad);
424 	num = ceph_decode_32(p);
425 	{
426 		u16 flags = ceph_decode_16(p);
427 		info->dir_end = !!(flags & CEPH_READDIR_FRAG_END);
428 		info->dir_complete = !!(flags & CEPH_READDIR_FRAG_COMPLETE);
429 		info->hash_order = !!(flags & CEPH_READDIR_HASH_ORDER);
430 		info->offset_hash = !!(flags & CEPH_READDIR_OFFSET_HASH);
431 	}
432 	if (num == 0)
433 		goto done;
434 
435 	BUG_ON(!info->dir_entries);
436 	if ((unsigned long)(info->dir_entries + num) >
437 	    (unsigned long)info->dir_entries + info->dir_buf_size) {
438 		pr_err_client(cl, "dir contents are larger than expected\n");
439 		WARN_ON(1);
440 		goto bad;
441 	}
442 
443 	info->dir_nr = num;
444 	while (num) {
445 		struct inode *inode = d_inode(req->r_dentry);
446 		struct ceph_inode_info *ci = ceph_inode(inode);
447 		struct ceph_mds_reply_dir_entry *rde = info->dir_entries + i;
448 		struct fscrypt_str tname = FSTR_INIT(NULL, 0);
449 		struct fscrypt_str oname = FSTR_INIT(NULL, 0);
450 		struct ceph_fname fname;
451 		u32 altname_len, _name_len;
452 		u8 *altname, *_name;
453 
454 		/* dentry */
455 		ceph_decode_32_safe(p, end, _name_len, bad);
456 		ceph_decode_need(p, end, _name_len, bad);
457 		_name = *p;
458 		*p += _name_len;
459 		doutc(cl, "parsed dir dname '%.*s'\n", _name_len, _name);
460 
461 		if (info->hash_order)
462 			rde->raw_hash = ceph_str_hash(ci->i_dir_layout.dl_dir_hash,
463 						      _name, _name_len);
464 
465 		/* dentry lease */
466 		err = parse_reply_info_lease(p, end, &rde->lease, features,
467 					     &altname_len, &altname);
468 		if (err)
469 			goto out_bad;
470 
471 		/*
472 		 * Try to dencrypt the dentry names and update them
473 		 * in the ceph_mds_reply_dir_entry struct.
474 		 */
475 		fname.dir = inode;
476 		fname.name = _name;
477 		fname.name_len = _name_len;
478 		fname.ctext = altname;
479 		fname.ctext_len = altname_len;
480 		/*
481 		 * The _name_len maybe larger than altname_len, such as
482 		 * when the human readable name length is in range of
483 		 * (CEPH_NOHASH_NAME_MAX, CEPH_NOHASH_NAME_MAX + SHA256_DIGEST_SIZE),
484 		 * then the copy in ceph_fname_to_usr will corrupt the
485 		 * data if there has no encryption key.
486 		 *
487 		 * Just set the no_copy flag and then if there has no
488 		 * encryption key the oname.name will be assigned to
489 		 * _name always.
490 		 */
491 		fname.no_copy = true;
492 		if (altname_len == 0) {
493 			/*
494 			 * Set tname to _name, and this will be used
495 			 * to do the base64_decode in-place. It's
496 			 * safe because the decoded string should
497 			 * always be shorter, which is 3/4 of origin
498 			 * string.
499 			 */
500 			tname.name = _name;
501 
502 			/*
503 			 * Set oname to _name too, and this will be
504 			 * used to do the dencryption in-place.
505 			 */
506 			oname.name = _name;
507 			oname.len = _name_len;
508 		} else {
509 			/*
510 			 * This will do the decryption only in-place
511 			 * from altname cryptext directly.
512 			 */
513 			oname.name = altname;
514 			oname.len = altname_len;
515 		}
516 		rde->is_nokey = false;
517 		err = ceph_fname_to_usr(&fname, &tname, &oname, &rde->is_nokey);
518 		if (err) {
519 			pr_err_client(cl, "unable to decode %.*s, got %d\n",
520 				      _name_len, _name, err);
521 			goto out_bad;
522 		}
523 		rde->name = oname.name;
524 		rde->name_len = oname.len;
525 
526 		/* inode */
527 		err = parse_reply_info_in(p, end, &rde->inode, features);
528 		if (err < 0)
529 			goto out_bad;
530 		/* ceph_readdir_prepopulate() will update it */
531 		rde->offset = 0;
532 		i++;
533 		num--;
534 	}
535 
536 done:
537 	/* Skip over any unrecognized fields */
538 	*p = end;
539 	return 0;
540 
541 bad:
542 	err = -EIO;
543 out_bad:
544 	pr_err_client(cl, "problem parsing dir contents %d\n", err);
545 	return err;
546 }
547 
548 /*
549  * parse fcntl F_GETLK results
550  */
551 static int parse_reply_info_filelock(void **p, void *end,
552 				     struct ceph_mds_reply_info_parsed *info,
553 				     u64 features)
554 {
555 	if (*p + sizeof(*info->filelock_reply) > end)
556 		goto bad;
557 
558 	info->filelock_reply = *p;
559 
560 	/* Skip over any unrecognized fields */
561 	*p = end;
562 	return 0;
563 bad:
564 	return -EIO;
565 }
566 
567 
568 #if BITS_PER_LONG == 64
569 
570 #define DELEGATED_INO_AVAILABLE		xa_mk_value(1)
571 
572 static int ceph_parse_deleg_inos(void **p, void *end,
573 				 struct ceph_mds_session *s)
574 {
575 	struct ceph_client *cl = s->s_mdsc->fsc->client;
576 	u32 sets;
577 
578 	ceph_decode_32_safe(p, end, sets, bad);
579 	doutc(cl, "got %u sets of delegated inodes\n", sets);
580 	while (sets--) {
581 		u64 start, len;
582 
583 		ceph_decode_64_safe(p, end, start, bad);
584 		ceph_decode_64_safe(p, end, len, bad);
585 
586 		/* Don't accept a delegation of system inodes */
587 		if (start < CEPH_INO_SYSTEM_BASE) {
588 			pr_warn_ratelimited_client(cl,
589 				"ignoring reserved inode range delegation (start=0x%llx len=0x%llx)\n",
590 				start, len);
591 			continue;
592 		}
593 		while (len--) {
594 			int err = xa_insert(&s->s_delegated_inos, start++,
595 					    DELEGATED_INO_AVAILABLE,
596 					    GFP_KERNEL);
597 			if (!err) {
598 				doutc(cl, "added delegated inode 0x%llx\n", start - 1);
599 			} else if (err == -EBUSY) {
600 				pr_warn_client(cl,
601 					"MDS delegated inode 0x%llx more than once.\n",
602 					start - 1);
603 			} else {
604 				return err;
605 			}
606 		}
607 	}
608 	return 0;
609 bad:
610 	return -EIO;
611 }
612 
613 u64 ceph_get_deleg_ino(struct ceph_mds_session *s)
614 {
615 	unsigned long ino;
616 	void *val;
617 
618 	xa_for_each(&s->s_delegated_inos, ino, val) {
619 		val = xa_erase(&s->s_delegated_inos, ino);
620 		if (val == DELEGATED_INO_AVAILABLE)
621 			return ino;
622 	}
623 	return 0;
624 }
625 
626 int ceph_restore_deleg_ino(struct ceph_mds_session *s, u64 ino)
627 {
628 	return xa_insert(&s->s_delegated_inos, ino, DELEGATED_INO_AVAILABLE,
629 			 GFP_KERNEL);
630 }
631 #else /* BITS_PER_LONG == 64 */
632 /*
633  * FIXME: xarrays can't handle 64-bit indexes on a 32-bit arch. For now, just
634  * ignore delegated_inos on 32 bit arch. Maybe eventually add xarrays for top
635  * and bottom words?
636  */
637 static int ceph_parse_deleg_inos(void **p, void *end,
638 				 struct ceph_mds_session *s)
639 {
640 	u32 sets;
641 
642 	ceph_decode_32_safe(p, end, sets, bad);
643 	if (sets)
644 		ceph_decode_skip_n(p, end, sets * 2 * sizeof(__le64), bad);
645 	return 0;
646 bad:
647 	return -EIO;
648 }
649 
650 u64 ceph_get_deleg_ino(struct ceph_mds_session *s)
651 {
652 	return 0;
653 }
654 
655 int ceph_restore_deleg_ino(struct ceph_mds_session *s, u64 ino)
656 {
657 	return 0;
658 }
659 #endif /* BITS_PER_LONG == 64 */
660 
661 /*
662  * parse create results
663  */
664 static int parse_reply_info_create(void **p, void *end,
665 				  struct ceph_mds_reply_info_parsed *info,
666 				  u64 features, struct ceph_mds_session *s)
667 {
668 	int ret;
669 
670 	if (features == (u64)-1 ||
671 	    (features & CEPH_FEATURE_REPLY_CREATE_INODE)) {
672 		if (*p == end) {
673 			/* Malformed reply? */
674 			info->has_create_ino = false;
675 		} else if (test_bit(CEPHFS_FEATURE_DELEG_INO, &s->s_features)) {
676 			info->has_create_ino = true;
677 			/* struct_v, struct_compat, and len */
678 			ceph_decode_skip_n(p, end, 2 + sizeof(u32), bad);
679 			ceph_decode_64_safe(p, end, info->ino, bad);
680 			ret = ceph_parse_deleg_inos(p, end, s);
681 			if (ret)
682 				return ret;
683 		} else {
684 			/* legacy */
685 			ceph_decode_64_safe(p, end, info->ino, bad);
686 			info->has_create_ino = true;
687 		}
688 	} else {
689 		if (*p != end)
690 			goto bad;
691 	}
692 
693 	/* Skip over any unrecognized fields */
694 	*p = end;
695 	return 0;
696 bad:
697 	return -EIO;
698 }
699 
700 static int parse_reply_info_getvxattr(void **p, void *end,
701 				      struct ceph_mds_reply_info_parsed *info,
702 				      u64 features)
703 {
704 	u32 value_len;
705 
706 	ceph_decode_skip_8(p, end, bad); /* skip current version: 1 */
707 	ceph_decode_skip_8(p, end, bad); /* skip first version: 1 */
708 	ceph_decode_skip_32(p, end, bad); /* skip payload length */
709 
710 	ceph_decode_32_safe(p, end, value_len, bad);
711 
712 	if (value_len == end - *p) {
713 	  info->xattr_info.xattr_value = *p;
714 	  info->xattr_info.xattr_value_len = value_len;
715 	  *p = end;
716 	  return value_len;
717 	}
718 bad:
719 	return -EIO;
720 }
721 
722 /*
723  * parse extra results
724  */
725 static int parse_reply_info_extra(void **p, void *end,
726 				  struct ceph_mds_request *req,
727 				  u64 features, struct ceph_mds_session *s)
728 {
729 	struct ceph_mds_reply_info_parsed *info = &req->r_reply_info;
730 	u32 op = le32_to_cpu(info->head->op);
731 
732 	if (op == CEPH_MDS_OP_GETFILELOCK)
733 		return parse_reply_info_filelock(p, end, info, features);
734 	else if (op == CEPH_MDS_OP_READDIR || op == CEPH_MDS_OP_LSSNAP)
735 		return parse_reply_info_readdir(p, end, req, features);
736 	else if (op == CEPH_MDS_OP_CREATE)
737 		return parse_reply_info_create(p, end, info, features, s);
738 	else if (op == CEPH_MDS_OP_GETVXATTR)
739 		return parse_reply_info_getvxattr(p, end, info, features);
740 	else
741 		return -EIO;
742 }
743 
744 /*
745  * parse entire mds reply
746  */
747 static int parse_reply_info(struct ceph_mds_session *s, struct ceph_msg *msg,
748 			    struct ceph_mds_request *req, u64 features)
749 {
750 	struct ceph_mds_reply_info_parsed *info = &req->r_reply_info;
751 	struct ceph_client *cl = s->s_mdsc->fsc->client;
752 	void *p, *end;
753 	u32 len;
754 	int err;
755 
756 	info->head = msg->front.iov_base;
757 	p = msg->front.iov_base + sizeof(struct ceph_mds_reply_head);
758 	end = p + msg->front.iov_len - sizeof(struct ceph_mds_reply_head);
759 
760 	/* trace */
761 	ceph_decode_32_safe(&p, end, len, bad);
762 	if (len > 0) {
763 		ceph_decode_need(&p, end, len, bad);
764 		err = parse_reply_info_trace(&p, p+len, info, features);
765 		if (err < 0)
766 			goto out_bad;
767 	}
768 
769 	/* extra */
770 	ceph_decode_32_safe(&p, end, len, bad);
771 	if (len > 0) {
772 		ceph_decode_need(&p, end, len, bad);
773 		err = parse_reply_info_extra(&p, p+len, req, features, s);
774 		if (err < 0)
775 			goto out_bad;
776 	}
777 
778 	/* snap blob */
779 	ceph_decode_32_safe(&p, end, len, bad);
780 	info->snapblob_len = len;
781 	info->snapblob = p;
782 	p += len;
783 
784 	if (p != end)
785 		goto bad;
786 	return 0;
787 
788 bad:
789 	err = -EIO;
790 out_bad:
791 	pr_err_client(cl, "mds parse_reply err %d\n", err);
792 	ceph_msg_dump(msg);
793 	return err;
794 }
795 
796 static void destroy_reply_info(struct ceph_mds_reply_info_parsed *info)
797 {
798 	int i;
799 
800 	kfree(info->diri.fscrypt_auth);
801 	kfree(info->diri.fscrypt_file);
802 	kfree(info->targeti.fscrypt_auth);
803 	kfree(info->targeti.fscrypt_file);
804 	if (!info->dir_entries)
805 		return;
806 
807 	for (i = 0; i < info->dir_nr; i++) {
808 		struct ceph_mds_reply_dir_entry *rde = info->dir_entries + i;
809 
810 		kfree(rde->inode.fscrypt_auth);
811 		kfree(rde->inode.fscrypt_file);
812 	}
813 	free_pages((unsigned long)info->dir_entries, get_order(info->dir_buf_size));
814 }
815 
816 /*
817  * In async unlink case the kclient won't wait for the first reply
818  * from MDS and just drop all the links and unhash the dentry and then
819  * succeeds immediately.
820  *
821  * For any new create/link/rename,etc requests followed by using the
822  * same file names we must wait for the first reply of the inflight
823  * unlink request, or the MDS possibly will fail these following
824  * requests with -EEXIST if the inflight async unlink request was
825  * delayed for some reasons.
826  *
827  * And the worst case is that for the none async openc request it will
828  * successfully open the file if the CDentry hasn't been unlinked yet,
829  * but later the previous delayed async unlink request will remove the
830  * CDenty. That means the just created file is possiblly deleted later
831  * by accident.
832  *
833  * We need to wait for the inflight async unlink requests to finish
834  * when creating new files/directories by using the same file names.
835  */
836 int ceph_wait_on_conflict_unlink(struct dentry *dentry)
837 {
838 	struct ceph_fs_client *fsc = ceph_sb_to_fs_client(dentry->d_sb);
839 	struct ceph_client *cl = fsc->client;
840 	struct dentry *pdentry = dentry->d_parent;
841 	struct dentry *udentry, *found = NULL;
842 	struct ceph_dentry_info *di;
843 	struct qstr dname;
844 	u32 hash = dentry->d_name.hash;
845 	int err;
846 
847 	dname.name = dentry->d_name.name;
848 	dname.len = dentry->d_name.len;
849 
850 	rcu_read_lock();
851 	hash_for_each_possible_rcu(fsc->async_unlink_conflict, di,
852 				   hnode, hash) {
853 		udentry = di->dentry;
854 
855 		spin_lock(&udentry->d_lock);
856 		if (udentry->d_name.hash != hash)
857 			goto next;
858 		if (unlikely(udentry->d_parent != pdentry))
859 			goto next;
860 		if (!hash_hashed(&di->hnode))
861 			goto next;
862 
863 		if (!test_bit(CEPH_DENTRY_ASYNC_UNLINK_BIT, &di->flags))
864 			pr_warn_client(cl, "dentry %p:%pd async unlink bit is not set\n",
865 				       dentry, dentry);
866 
867 		if (!d_same_name(udentry, pdentry, &dname))
868 			goto next;
869 
870 		found = dget_dlock(udentry);
871 		spin_unlock(&udentry->d_lock);
872 		break;
873 next:
874 		spin_unlock(&udentry->d_lock);
875 	}
876 	rcu_read_unlock();
877 
878 	if (likely(!found))
879 		return 0;
880 
881 	doutc(cl, "dentry %p:%pd conflict with old %p:%pd\n", dentry, dentry,
882 	      found, found);
883 
884 	err = wait_on_bit(&di->flags, CEPH_DENTRY_ASYNC_UNLINK_BIT,
885 			  TASK_KILLABLE);
886 	dput(found);
887 	return err;
888 }
889 
890 
891 /*
892  * sessions
893  */
894 const char *ceph_session_state_name(int s)
895 {
896 	switch (s) {
897 	case CEPH_MDS_SESSION_NEW: return "new";
898 	case CEPH_MDS_SESSION_OPENING: return "opening";
899 	case CEPH_MDS_SESSION_OPEN: return "open";
900 	case CEPH_MDS_SESSION_HUNG: return "hung";
901 	case CEPH_MDS_SESSION_CLOSING: return "closing";
902 	case CEPH_MDS_SESSION_CLOSED: return "closed";
903 	case CEPH_MDS_SESSION_RESTARTING: return "restarting";
904 	case CEPH_MDS_SESSION_RECONNECTING: return "reconnecting";
905 	case CEPH_MDS_SESSION_REJECTED: return "rejected";
906 	default: return "???";
907 	}
908 }
909 
910 struct ceph_mds_session *ceph_get_mds_session(struct ceph_mds_session *s)
911 {
912 	if (refcount_inc_not_zero(&s->s_ref))
913 		return s;
914 	return NULL;
915 }
916 
917 void ceph_put_mds_session(struct ceph_mds_session *s)
918 {
919 	if (IS_ERR_OR_NULL(s))
920 		return;
921 
922 	if (refcount_dec_and_test(&s->s_ref)) {
923 		if (s->s_auth.authorizer)
924 			ceph_auth_destroy_authorizer(s->s_auth.authorizer);
925 		WARN_ON(mutex_is_locked(&s->s_mutex));
926 		xa_destroy(&s->s_delegated_inos);
927 		kfree(s);
928 	}
929 }
930 
931 /*
932  * called under mdsc->mutex
933  */
934 struct ceph_mds_session *__ceph_lookup_mds_session(struct ceph_mds_client *mdsc,
935 						   int mds)
936 {
937 	if (mds >= mdsc->max_sessions || !mdsc->sessions[mds])
938 		return NULL;
939 	return ceph_get_mds_session(mdsc->sessions[mds]);
940 }
941 
942 static bool __have_session(struct ceph_mds_client *mdsc, int mds)
943 {
944 	if (mds >= mdsc->max_sessions || !mdsc->sessions[mds])
945 		return false;
946 	else
947 		return true;
948 }
949 
950 static int __verify_registered_session(struct ceph_mds_client *mdsc,
951 				       struct ceph_mds_session *s)
952 {
953 	if (s->s_mds >= mdsc->max_sessions ||
954 	    mdsc->sessions[s->s_mds] != s)
955 		return -ENOENT;
956 	return 0;
957 }
958 
959 /*
960  * create+register a new session for given mds.
961  * called under mdsc->mutex.
962  */
963 static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
964 						 int mds)
965 {
966 	struct ceph_client *cl = mdsc->fsc->client;
967 	struct ceph_mds_session *s;
968 
969 	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_FENCE_IO)
970 		return ERR_PTR(-EIO);
971 
972 	if (mds >= mdsc->mdsmap->possible_max_rank)
973 		return ERR_PTR(-EINVAL);
974 
975 	s = kzalloc(sizeof(*s), GFP_NOFS);
976 	if (!s)
977 		return ERR_PTR(-ENOMEM);
978 
979 	if (mds >= mdsc->max_sessions) {
980 		int newmax = 1 << get_count_order(mds + 1);
981 		struct ceph_mds_session **sa;
982 
983 		doutc(cl, "realloc to %d\n", newmax);
984 		sa = kcalloc(newmax, sizeof(void *), GFP_NOFS);
985 		if (!sa)
986 			goto fail_realloc;
987 		if (mdsc->sessions) {
988 			memcpy(sa, mdsc->sessions,
989 			       mdsc->max_sessions * sizeof(void *));
990 			kfree(mdsc->sessions);
991 		}
992 		mdsc->sessions = sa;
993 		mdsc->max_sessions = newmax;
994 	}
995 
996 	doutc(cl, "mds%d\n", mds);
997 	s->s_mdsc = mdsc;
998 	s->s_mds = mds;
999 	s->s_state = CEPH_MDS_SESSION_NEW;
1000 	mutex_init(&s->s_mutex);
1001 
1002 	ceph_con_init(&s->s_con, s, &mds_con_ops, &mdsc->fsc->client->msgr);
1003 
1004 	atomic_set(&s->s_cap_gen, 1);
1005 	s->s_cap_ttl = jiffies - 1;
1006 
1007 	spin_lock_init(&s->s_cap_lock);
1008 	INIT_LIST_HEAD(&s->s_caps);
1009 	refcount_set(&s->s_ref, 1);
1010 	INIT_LIST_HEAD(&s->s_waiting);
1011 	INIT_LIST_HEAD(&s->s_unsafe);
1012 	xa_init(&s->s_delegated_inos);
1013 	INIT_LIST_HEAD(&s->s_cap_releases);
1014 	INIT_WORK(&s->s_cap_release_work, ceph_cap_release_work);
1015 
1016 	INIT_LIST_HEAD(&s->s_cap_dirty);
1017 	INIT_LIST_HEAD(&s->s_cap_flushing);
1018 
1019 	mdsc->sessions[mds] = s;
1020 	atomic_inc(&mdsc->num_sessions);
1021 	refcount_inc(&s->s_ref);  /* one ref to sessions[], one to caller */
1022 
1023 	ceph_con_open(&s->s_con, CEPH_ENTITY_TYPE_MDS, mds,
1024 		      ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
1025 
1026 	return s;
1027 
1028 fail_realloc:
1029 	kfree(s);
1030 	return ERR_PTR(-ENOMEM);
1031 }
1032 
1033 /*
1034  * called under mdsc->mutex
1035  */
1036 static void __unregister_session(struct ceph_mds_client *mdsc,
1037 			       struct ceph_mds_session *s)
1038 {
1039 	doutc(mdsc->fsc->client, "mds%d %p\n", s->s_mds, s);
1040 	BUG_ON(mdsc->sessions[s->s_mds] != s);
1041 	mdsc->sessions[s->s_mds] = NULL;
1042 	ceph_con_close(&s->s_con);
1043 	ceph_put_mds_session(s);
1044 	atomic_dec(&mdsc->num_sessions);
1045 }
1046 
1047 /*
1048  * drop session refs in request.
1049  *
1050  * should be last request ref, or hold mdsc->mutex
1051  */
1052 static void put_request_session(struct ceph_mds_request *req)
1053 {
1054 	if (req->r_session) {
1055 		ceph_put_mds_session(req->r_session);
1056 		req->r_session = NULL;
1057 	}
1058 }
1059 
1060 void ceph_mdsc_iterate_sessions(struct ceph_mds_client *mdsc,
1061 				void (*cb)(struct ceph_mds_session *),
1062 				bool check_state)
1063 {
1064 	int mds;
1065 
1066 	mutex_lock(&mdsc->mutex);
1067 	for (mds = 0; mds < mdsc->max_sessions; ++mds) {
1068 		struct ceph_mds_session *s;
1069 
1070 		s = __ceph_lookup_mds_session(mdsc, mds);
1071 		if (!s)
1072 			continue;
1073 
1074 		if (check_state && !check_session_state(s)) {
1075 			ceph_put_mds_session(s);
1076 			continue;
1077 		}
1078 
1079 		mutex_unlock(&mdsc->mutex);
1080 		cb(s);
1081 		ceph_put_mds_session(s);
1082 		mutex_lock(&mdsc->mutex);
1083 	}
1084 	mutex_unlock(&mdsc->mutex);
1085 }
1086 
1087 void ceph_mdsc_release_request(struct kref *kref)
1088 {
1089 	struct ceph_mds_request *req = container_of(kref,
1090 						    struct ceph_mds_request,
1091 						    r_kref);
1092 	ceph_mdsc_release_dir_caps_no_check(req);
1093 	destroy_reply_info(&req->r_reply_info);
1094 	if (req->r_request)
1095 		ceph_msg_put(req->r_request);
1096 	if (req->r_reply)
1097 		ceph_msg_put(req->r_reply);
1098 	if (req->r_inode) {
1099 		ceph_put_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
1100 		iput(req->r_inode);
1101 	}
1102 	if (req->r_parent) {
1103 		ceph_put_cap_refs(ceph_inode(req->r_parent), CEPH_CAP_PIN);
1104 		iput(req->r_parent);
1105 	}
1106 	iput(req->r_target_inode);
1107 	iput(req->r_new_inode);
1108 	if (req->r_dentry)
1109 		dput(req->r_dentry);
1110 	if (req->r_old_dentry)
1111 		dput(req->r_old_dentry);
1112 	if (req->r_old_dentry_dir) {
1113 		/*
1114 		 * track (and drop pins for) r_old_dentry_dir
1115 		 * separately, since r_old_dentry's d_parent may have
1116 		 * changed between the dir mutex being dropped and
1117 		 * this request being freed.
1118 		 */
1119 		ceph_put_cap_refs(ceph_inode(req->r_old_dentry_dir),
1120 				  CEPH_CAP_PIN);
1121 		iput(req->r_old_dentry_dir);
1122 	}
1123 	kfree(req->r_path1);
1124 	kfree(req->r_path2);
1125 	put_cred(req->r_cred);
1126 	if (req->r_mnt_idmap)
1127 		mnt_idmap_put(req->r_mnt_idmap);
1128 	if (req->r_pagelist)
1129 		ceph_pagelist_release(req->r_pagelist);
1130 	kfree(req->r_fscrypt_auth);
1131 	kfree(req->r_altname);
1132 	put_request_session(req);
1133 	ceph_unreserve_caps(req->r_mdsc, &req->r_caps_reservation);
1134 	WARN_ON_ONCE(!list_empty(&req->r_wait));
1135 	kmem_cache_free(ceph_mds_request_cachep, req);
1136 }
1137 
1138 DEFINE_RB_FUNCS(request, struct ceph_mds_request, r_tid, r_node)
1139 
1140 /*
1141  * lookup session, bump ref if found.
1142  *
1143  * called under mdsc->mutex.
1144  */
1145 static struct ceph_mds_request *
1146 lookup_get_request(struct ceph_mds_client *mdsc, u64 tid)
1147 {
1148 	struct ceph_mds_request *req;
1149 
1150 	req = lookup_request(&mdsc->request_tree, tid);
1151 	if (req)
1152 		ceph_mdsc_get_request(req);
1153 
1154 	return req;
1155 }
1156 
1157 /*
1158  * Register an in-flight request, and assign a tid.  Link to directory
1159  * are modifying (if any).
1160  *
1161  * Called under mdsc->mutex.
1162  */
1163 static void __register_request(struct ceph_mds_client *mdsc,
1164 			       struct ceph_mds_request *req,
1165 			       struct inode *dir)
1166 {
1167 	struct ceph_client *cl = mdsc->fsc->client;
1168 	int ret = 0;
1169 
1170 	req->r_tid = ++mdsc->last_tid;
1171 	if (req->r_num_caps) {
1172 		ret = ceph_reserve_caps(mdsc, &req->r_caps_reservation,
1173 					req->r_num_caps);
1174 		if (ret < 0) {
1175 			pr_err_client(cl, "%p failed to reserve caps: %d\n",
1176 				      req, ret);
1177 			/* set req->r_err to fail early from __do_request */
1178 			req->r_err = ret;
1179 			return;
1180 		}
1181 	}
1182 	doutc(cl, "%p tid %lld\n", req, req->r_tid);
1183 	ceph_mdsc_get_request(req);
1184 	insert_request(&mdsc->request_tree, req);
1185 
1186 	req->r_cred = get_current_cred();
1187 	if (!req->r_mnt_idmap)
1188 		req->r_mnt_idmap = &nop_mnt_idmap;
1189 
1190 	if (mdsc->oldest_tid == 0 && req->r_op != CEPH_MDS_OP_SETFILELOCK)
1191 		mdsc->oldest_tid = req->r_tid;
1192 
1193 	if (dir) {
1194 		struct ceph_inode_info *ci = ceph_inode(dir);
1195 
1196 		ihold(dir);
1197 		req->r_unsafe_dir = dir;
1198 		spin_lock(&ci->i_unsafe_lock);
1199 		list_add_tail(&req->r_unsafe_dir_item, &ci->i_unsafe_dirops);
1200 		spin_unlock(&ci->i_unsafe_lock);
1201 	}
1202 }
1203 
1204 static void __unregister_request(struct ceph_mds_client *mdsc,
1205 				 struct ceph_mds_request *req)
1206 {
1207 	doutc(mdsc->fsc->client, "%p tid %lld\n", req, req->r_tid);
1208 
1209 	/* Never leave an unregistered request on an unsafe list! */
1210 	list_del_init(&req->r_unsafe_item);
1211 
1212 	if (req->r_tid == mdsc->oldest_tid) {
1213 		struct rb_node *p = rb_next(&req->r_node);
1214 		mdsc->oldest_tid = 0;
1215 		while (p) {
1216 			struct ceph_mds_request *next_req =
1217 				rb_entry(p, struct ceph_mds_request, r_node);
1218 			if (next_req->r_op != CEPH_MDS_OP_SETFILELOCK) {
1219 				mdsc->oldest_tid = next_req->r_tid;
1220 				break;
1221 			}
1222 			p = rb_next(p);
1223 		}
1224 	}
1225 
1226 	erase_request(&mdsc->request_tree, req);
1227 
1228 	if (req->r_unsafe_dir) {
1229 		struct ceph_inode_info *ci = ceph_inode(req->r_unsafe_dir);
1230 		spin_lock(&ci->i_unsafe_lock);
1231 		list_del_init(&req->r_unsafe_dir_item);
1232 		spin_unlock(&ci->i_unsafe_lock);
1233 	}
1234 	if (req->r_target_inode &&
1235 	    test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
1236 		struct ceph_inode_info *ci = ceph_inode(req->r_target_inode);
1237 		spin_lock(&ci->i_unsafe_lock);
1238 		list_del_init(&req->r_unsafe_target_item);
1239 		spin_unlock(&ci->i_unsafe_lock);
1240 	}
1241 
1242 	if (req->r_unsafe_dir) {
1243 		iput(req->r_unsafe_dir);
1244 		req->r_unsafe_dir = NULL;
1245 	}
1246 
1247 	complete_all(&req->r_safe_completion);
1248 
1249 	ceph_mdsc_put_request(req);
1250 }
1251 
1252 /*
1253  * Walk back up the dentry tree until we hit a dentry representing a
1254  * non-snapshot inode. We do this using the rcu_read_lock (which must be held
1255  * when calling this) to ensure that the objects won't disappear while we're
1256  * working with them. Once we hit a candidate dentry, we attempt to take a
1257  * reference to it, and return that as the result.
1258  */
1259 static struct inode *get_nonsnap_parent(struct dentry *dentry)
1260 {
1261 	struct inode *inode = NULL;
1262 
1263 	while (dentry && !IS_ROOT(dentry)) {
1264 		inode = d_inode_rcu(dentry);
1265 		if (!inode || ceph_snap(inode) == CEPH_NOSNAP)
1266 			break;
1267 		dentry = dentry->d_parent;
1268 	}
1269 	if (inode)
1270 		inode = igrab(inode);
1271 	return inode;
1272 }
1273 
1274 /*
1275  * Choose mds to send request to next.  If there is a hint set in the
1276  * request (e.g., due to a prior forward hint from the mds), use that.
1277  * Otherwise, consult frag tree and/or caps to identify the
1278  * appropriate mds.  If all else fails, choose randomly.
1279  *
1280  * Called under mdsc->mutex.
1281  */
1282 static int __choose_mds(struct ceph_mds_client *mdsc,
1283 			struct ceph_mds_request *req,
1284 			bool *random)
1285 {
1286 	struct inode *inode;
1287 	struct ceph_inode_info *ci;
1288 	struct ceph_cap *cap;
1289 	int mode = req->r_direct_mode;
1290 	int mds = -1;
1291 	u32 hash = req->r_direct_hash;
1292 	bool is_hash = test_bit(CEPH_MDS_R_DIRECT_IS_HASH, &req->r_req_flags);
1293 	struct ceph_client *cl = mdsc->fsc->client;
1294 
1295 	if (random)
1296 		*random = false;
1297 
1298 	/*
1299 	 * is there a specific mds we should try?  ignore hint if we have
1300 	 * no session and the mds is not up (active or recovering).
1301 	 */
1302 	if (req->r_resend_mds >= 0 &&
1303 	    (__have_session(mdsc, req->r_resend_mds) ||
1304 	     ceph_mdsmap_get_state(mdsc->mdsmap, req->r_resend_mds) > 0)) {
1305 		doutc(cl, "using resend_mds mds%d\n", req->r_resend_mds);
1306 		return req->r_resend_mds;
1307 	}
1308 
1309 	if (mode == USE_RANDOM_MDS)
1310 		goto random;
1311 
1312 	inode = NULL;
1313 	if (req->r_inode) {
1314 		if (ceph_snap(req->r_inode) != CEPH_SNAPDIR) {
1315 			inode = req->r_inode;
1316 			ihold(inode);
1317 		} else {
1318 			/* req->r_dentry is non-null for LSSNAP request */
1319 			rcu_read_lock();
1320 			inode = get_nonsnap_parent(req->r_dentry);
1321 			rcu_read_unlock();
1322 			doutc(cl, "using snapdir's parent %p %llx.%llx\n",
1323 			      inode, ceph_vinop(inode));
1324 		}
1325 	} else if (req->r_dentry) {
1326 		/* ignore race with rename; old or new d_parent is okay */
1327 		struct dentry *parent;
1328 		struct inode *dir;
1329 
1330 		rcu_read_lock();
1331 		parent = READ_ONCE(req->r_dentry->d_parent);
1332 		dir = req->r_parent ? : d_inode_rcu(parent);
1333 
1334 		if (!dir || dir->i_sb != mdsc->fsc->sb) {
1335 			/*  not this fs or parent went negative */
1336 			inode = d_inode(req->r_dentry);
1337 			if (inode)
1338 				ihold(inode);
1339 		} else if (ceph_snap(dir) != CEPH_NOSNAP) {
1340 			/* direct snapped/virtual snapdir requests
1341 			 * based on parent dir inode */
1342 			inode = get_nonsnap_parent(parent);
1343 			doutc(cl, "using nonsnap parent %p %llx.%llx\n",
1344 			      inode, ceph_vinop(inode));
1345 		} else {
1346 			/* dentry target */
1347 			inode = d_inode(req->r_dentry);
1348 			if (!inode || mode == USE_AUTH_MDS) {
1349 				/* dir + name */
1350 				inode = igrab(dir);
1351 				hash = ceph_dentry_hash(dir, req->r_dentry);
1352 				is_hash = true;
1353 			} else {
1354 				ihold(inode);
1355 			}
1356 		}
1357 		rcu_read_unlock();
1358 	}
1359 
1360 	if (!inode)
1361 		goto random;
1362 
1363 	doutc(cl, "%p %llx.%llx is_hash=%d (0x%x) mode %d\n", inode,
1364 	      ceph_vinop(inode), (int)is_hash, hash, mode);
1365 	ci = ceph_inode(inode);
1366 
1367 	if (is_hash && S_ISDIR(inode->i_mode)) {
1368 		struct ceph_inode_frag frag;
1369 		int found;
1370 
1371 		ceph_choose_frag(ci, hash, &frag, &found);
1372 		if (found) {
1373 			if (mode == USE_ANY_MDS && frag.ndist > 0) {
1374 				u8 r;
1375 
1376 				/* choose a random replica */
1377 				get_random_bytes(&r, 1);
1378 				r %= frag.ndist;
1379 				mds = frag.dist[r];
1380 				doutc(cl, "%p %llx.%llx frag %u mds%d (%d/%d)\n",
1381 				      inode, ceph_vinop(inode), frag.frag,
1382 				      mds, (int)r, frag.ndist);
1383 				if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
1384 				    CEPH_MDS_STATE_ACTIVE &&
1385 				    !ceph_mdsmap_is_laggy(mdsc->mdsmap, mds))
1386 					goto out;
1387 			}
1388 
1389 			/* since this file/dir wasn't known to be
1390 			 * replicated, then we want to look for the
1391 			 * authoritative mds. */
1392 			if (frag.mds >= 0) {
1393 				/* choose auth mds */
1394 				mds = frag.mds;
1395 				doutc(cl, "%p %llx.%llx frag %u mds%d (auth)\n",
1396 				      inode, ceph_vinop(inode), frag.frag, mds);
1397 				if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
1398 				    CEPH_MDS_STATE_ACTIVE) {
1399 					if (!ceph_mdsmap_is_laggy(mdsc->mdsmap,
1400 								  mds))
1401 						goto out;
1402 				}
1403 			}
1404 			mode = USE_AUTH_MDS;
1405 		}
1406 	}
1407 
1408 	spin_lock(&ci->i_ceph_lock);
1409 	cap = NULL;
1410 	if (mode == USE_AUTH_MDS)
1411 		cap = ci->i_auth_cap;
1412 	if (!cap && !RB_EMPTY_ROOT(&ci->i_caps))
1413 		cap = rb_entry(rb_first(&ci->i_caps), struct ceph_cap, ci_node);
1414 	if (!cap) {
1415 		spin_unlock(&ci->i_ceph_lock);
1416 		iput(inode);
1417 		goto random;
1418 	}
1419 	mds = cap->session->s_mds;
1420 	doutc(cl, "%p %llx.%llx mds%d (%scap %p)\n", inode,
1421 	      ceph_vinop(inode), mds,
1422 	      cap == ci->i_auth_cap ? "auth " : "", cap);
1423 	spin_unlock(&ci->i_ceph_lock);
1424 out:
1425 	iput(inode);
1426 	return mds;
1427 
1428 random:
1429 	if (random)
1430 		*random = true;
1431 
1432 	mds = ceph_mdsmap_get_random_mds(mdsc->mdsmap);
1433 	doutc(cl, "chose random mds%d\n", mds);
1434 	return mds;
1435 }
1436 
1437 
1438 /*
1439  * session messages
1440  */
1441 struct ceph_msg *ceph_create_session_msg(u32 op, u64 seq)
1442 {
1443 	struct ceph_msg *msg;
1444 	struct ceph_mds_session_head *h;
1445 
1446 	msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h), GFP_NOFS,
1447 			   false);
1448 	if (!msg) {
1449 		pr_err("ENOMEM creating session %s msg\n",
1450 		       ceph_session_op_name(op));
1451 		return NULL;
1452 	}
1453 	h = msg->front.iov_base;
1454 	h->op = cpu_to_le32(op);
1455 	h->seq = cpu_to_le64(seq);
1456 
1457 	return msg;
1458 }
1459 
1460 static const unsigned char feature_bits[] = CEPHFS_FEATURES_CLIENT_SUPPORTED;
1461 #define FEATURE_BYTES(c) (DIV_ROUND_UP((size_t)feature_bits[c - 1] + 1, 64) * 8)
1462 static int encode_supported_features(void **p, void *end)
1463 {
1464 	static const size_t count = ARRAY_SIZE(feature_bits);
1465 
1466 	if (count > 0) {
1467 		size_t i;
1468 		size_t size = FEATURE_BYTES(count);
1469 		unsigned long bit;
1470 
1471 		if (WARN_ON_ONCE(*p + 4 + size > end))
1472 			return -ERANGE;
1473 
1474 		ceph_encode_32(p, size);
1475 		memset(*p, 0, size);
1476 		for (i = 0; i < count; i++) {
1477 			bit = feature_bits[i];
1478 			((unsigned char *)(*p))[bit / 8] |= BIT(bit % 8);
1479 		}
1480 		*p += size;
1481 	} else {
1482 		if (WARN_ON_ONCE(*p + 4 > end))
1483 			return -ERANGE;
1484 
1485 		ceph_encode_32(p, 0);
1486 	}
1487 
1488 	return 0;
1489 }
1490 
1491 static const unsigned char metric_bits[] = CEPHFS_METRIC_SPEC_CLIENT_SUPPORTED;
1492 #define METRIC_BYTES(cnt) (DIV_ROUND_UP((size_t)metric_bits[cnt - 1] + 1, 64) * 8)
1493 static int encode_metric_spec(void **p, void *end)
1494 {
1495 	static const size_t count = ARRAY_SIZE(metric_bits);
1496 
1497 	/* header */
1498 	if (WARN_ON_ONCE(*p + 2 > end))
1499 		return -ERANGE;
1500 
1501 	ceph_encode_8(p, 1); /* version */
1502 	ceph_encode_8(p, 1); /* compat */
1503 
1504 	if (count > 0) {
1505 		size_t i;
1506 		size_t size = METRIC_BYTES(count);
1507 
1508 		if (WARN_ON_ONCE(*p + 4 + 4 + size > end))
1509 			return -ERANGE;
1510 
1511 		/* metric spec info length */
1512 		ceph_encode_32(p, 4 + size);
1513 
1514 		/* metric spec */
1515 		ceph_encode_32(p, size);
1516 		memset(*p, 0, size);
1517 		for (i = 0; i < count; i++)
1518 			((unsigned char *)(*p))[i / 8] |= BIT(metric_bits[i] % 8);
1519 		*p += size;
1520 	} else {
1521 		if (WARN_ON_ONCE(*p + 4 + 4 > end))
1522 			return -ERANGE;
1523 
1524 		/* metric spec info length */
1525 		ceph_encode_32(p, 4);
1526 		/* metric spec */
1527 		ceph_encode_32(p, 0);
1528 	}
1529 
1530 	return 0;
1531 }
1532 
1533 /*
1534  * session message, specialization for CEPH_SESSION_REQUEST_OPEN
1535  * to include additional client metadata fields.
1536  */
1537 static struct ceph_msg *
1538 create_session_full_msg(struct ceph_mds_client *mdsc, int op, u64 seq)
1539 {
1540 	struct ceph_msg *msg;
1541 	struct ceph_mds_session_head *h;
1542 	int i;
1543 	int extra_bytes = 0;
1544 	int metadata_key_count = 0;
1545 	struct ceph_options *opt = mdsc->fsc->client->options;
1546 	struct ceph_mount_options *fsopt = mdsc->fsc->mount_options;
1547 	struct ceph_client *cl = mdsc->fsc->client;
1548 	size_t size, count;
1549 	void *p, *end;
1550 	int ret;
1551 
1552 	const char* metadata[][2] = {
1553 		{"hostname", mdsc->nodename},
1554 		{"kernel_version", init_utsname()->release},
1555 		{"entity_id", opt->name ? : ""},
1556 		{"root", fsopt->server_path ? : "/"},
1557 		{NULL, NULL}
1558 	};
1559 
1560 	/* Calculate serialized length of metadata */
1561 	extra_bytes = 4;  /* map length */
1562 	for (i = 0; metadata[i][0]; ++i) {
1563 		extra_bytes += 8 + strlen(metadata[i][0]) +
1564 			strlen(metadata[i][1]);
1565 		metadata_key_count++;
1566 	}
1567 
1568 	/* supported feature */
1569 	size = 0;
1570 	count = ARRAY_SIZE(feature_bits);
1571 	if (count > 0)
1572 		size = FEATURE_BYTES(count);
1573 	extra_bytes += 4 + size;
1574 
1575 	/* metric spec */
1576 	size = 0;
1577 	count = ARRAY_SIZE(metric_bits);
1578 	if (count > 0)
1579 		size = METRIC_BYTES(count);
1580 	extra_bytes += 2 + 4 + 4 + size;
1581 
1582 	/* flags, mds auth caps and oldest_client_tid */
1583 	extra_bytes += 4 + 4 + 8;
1584 
1585 	/* Allocate the message */
1586 	msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h) + extra_bytes,
1587 			   GFP_NOFS, false);
1588 	if (!msg) {
1589 		pr_err_client(cl, "ENOMEM creating session open msg\n");
1590 		return ERR_PTR(-ENOMEM);
1591 	}
1592 	p = msg->front.iov_base;
1593 	end = p + msg->front.iov_len;
1594 
1595 	h = p;
1596 	h->op = cpu_to_le32(op);
1597 	h->seq = cpu_to_le64(seq);
1598 
1599 	/*
1600 	 * Serialize client metadata into waiting buffer space, using
1601 	 * the format that userspace expects for map<string, string>
1602 	 *
1603 	 * ClientSession messages with metadata are v7
1604 	 */
1605 	msg->hdr.version = cpu_to_le16(7);
1606 	msg->hdr.compat_version = cpu_to_le16(1);
1607 
1608 	/* The write pointer, following the session_head structure */
1609 	p += sizeof(*h);
1610 
1611 	/* Number of entries in the map */
1612 	ceph_encode_32(&p, metadata_key_count);
1613 
1614 	/* Two length-prefixed strings for each entry in the map */
1615 	for (i = 0; metadata[i][0]; ++i) {
1616 		size_t const key_len = strlen(metadata[i][0]);
1617 		size_t const val_len = strlen(metadata[i][1]);
1618 
1619 		ceph_encode_32(&p, key_len);
1620 		memcpy(p, metadata[i][0], key_len);
1621 		p += key_len;
1622 		ceph_encode_32(&p, val_len);
1623 		memcpy(p, metadata[i][1], val_len);
1624 		p += val_len;
1625 	}
1626 
1627 	ret = encode_supported_features(&p, end);
1628 	if (ret) {
1629 		pr_err_client(cl, "encode_supported_features failed!\n");
1630 		ceph_msg_put(msg);
1631 		return ERR_PTR(ret);
1632 	}
1633 
1634 	ret = encode_metric_spec(&p, end);
1635 	if (ret) {
1636 		pr_err_client(cl, "encode_metric_spec failed!\n");
1637 		ceph_msg_put(msg);
1638 		return ERR_PTR(ret);
1639 	}
1640 
1641 	/* version == 5, flags */
1642 	ceph_encode_32(&p, 0);
1643 
1644 	/* version == 6, mds auth caps */
1645 	ceph_encode_32(&p, 0);
1646 
1647 	/* version == 7, oldest_client_tid */
1648 	ceph_encode_64(&p, mdsc->oldest_tid);
1649 
1650 	msg->front.iov_len = p - msg->front.iov_base;
1651 	msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
1652 
1653 	return msg;
1654 }
1655 
1656 /*
1657  * send session open request.
1658  *
1659  * called under mdsc->mutex
1660  */
1661 static int __open_session(struct ceph_mds_client *mdsc,
1662 			  struct ceph_mds_session *session)
1663 {
1664 	struct ceph_msg *msg;
1665 	int mstate;
1666 	int mds = session->s_mds;
1667 
1668 	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_FENCE_IO)
1669 		return -EIO;
1670 
1671 	/* wait for mds to go active? */
1672 	mstate = ceph_mdsmap_get_state(mdsc->mdsmap, mds);
1673 	doutc(mdsc->fsc->client, "open_session to mds%d (%s)\n", mds,
1674 	      ceph_mds_state_name(mstate));
1675 	session->s_state = CEPH_MDS_SESSION_OPENING;
1676 	session->s_renew_requested = jiffies;
1677 
1678 	/* send connect message */
1679 	msg = create_session_full_msg(mdsc, CEPH_SESSION_REQUEST_OPEN,
1680 				      session->s_seq);
1681 	if (IS_ERR(msg))
1682 		return PTR_ERR(msg);
1683 	ceph_con_send(&session->s_con, msg);
1684 	return 0;
1685 }
1686 
1687 /*
1688  * open sessions for any export targets for the given mds
1689  *
1690  * called under mdsc->mutex
1691  */
1692 static struct ceph_mds_session *
1693 __open_export_target_session(struct ceph_mds_client *mdsc, int target)
1694 {
1695 	struct ceph_mds_session *session;
1696 	int ret;
1697 
1698 	session = __ceph_lookup_mds_session(mdsc, target);
1699 	if (!session) {
1700 		session = register_session(mdsc, target);
1701 		if (IS_ERR(session))
1702 			return session;
1703 	}
1704 	if (session->s_state == CEPH_MDS_SESSION_NEW ||
1705 	    session->s_state == CEPH_MDS_SESSION_CLOSING) {
1706 		ret = __open_session(mdsc, session);
1707 		if (ret)
1708 			return ERR_PTR(ret);
1709 	}
1710 
1711 	return session;
1712 }
1713 
1714 struct ceph_mds_session *
1715 ceph_mdsc_open_export_target_session(struct ceph_mds_client *mdsc, int target)
1716 {
1717 	struct ceph_mds_session *session;
1718 	struct ceph_client *cl = mdsc->fsc->client;
1719 
1720 	doutc(cl, "to mds%d\n", target);
1721 
1722 	mutex_lock(&mdsc->mutex);
1723 	session = __open_export_target_session(mdsc, target);
1724 	mutex_unlock(&mdsc->mutex);
1725 
1726 	return session;
1727 }
1728 
1729 static void __open_export_target_sessions(struct ceph_mds_client *mdsc,
1730 					  struct ceph_mds_session *session)
1731 {
1732 	struct ceph_mds_info *mi;
1733 	struct ceph_mds_session *ts;
1734 	int i, mds = session->s_mds;
1735 	struct ceph_client *cl = mdsc->fsc->client;
1736 
1737 	if (mds >= mdsc->mdsmap->possible_max_rank)
1738 		return;
1739 
1740 	mi = &mdsc->mdsmap->m_info[mds];
1741 	doutc(cl, "for mds%d (%d targets)\n", session->s_mds,
1742 	      mi->num_export_targets);
1743 
1744 	for (i = 0; i < mi->num_export_targets; i++) {
1745 		ts = __open_export_target_session(mdsc, mi->export_targets[i]);
1746 		ceph_put_mds_session(ts);
1747 	}
1748 }
1749 
1750 void ceph_mdsc_open_export_target_sessions(struct ceph_mds_client *mdsc,
1751 					   struct ceph_mds_session *session)
1752 {
1753 	mutex_lock(&mdsc->mutex);
1754 	__open_export_target_sessions(mdsc, session);
1755 	mutex_unlock(&mdsc->mutex);
1756 }
1757 
1758 /*
1759  * session caps
1760  */
1761 
1762 static void detach_cap_releases(struct ceph_mds_session *session,
1763 				struct list_head *target)
1764 {
1765 	struct ceph_client *cl = session->s_mdsc->fsc->client;
1766 
1767 	lockdep_assert_held(&session->s_cap_lock);
1768 
1769 	list_splice_init(&session->s_cap_releases, target);
1770 	session->s_num_cap_releases = 0;
1771 	doutc(cl, "mds%d\n", session->s_mds);
1772 }
1773 
1774 static void dispose_cap_releases(struct ceph_mds_client *mdsc,
1775 				 struct list_head *dispose)
1776 {
1777 	while (!list_empty(dispose)) {
1778 		struct ceph_cap *cap;
1779 		/* zero out the in-progress message */
1780 		cap = list_first_entry(dispose, struct ceph_cap, session_caps);
1781 		list_del(&cap->session_caps);
1782 		ceph_put_cap(mdsc, cap);
1783 	}
1784 }
1785 
1786 static void cleanup_session_requests(struct ceph_mds_client *mdsc,
1787 				     struct ceph_mds_session *session)
1788 {
1789 	struct ceph_client *cl = mdsc->fsc->client;
1790 	struct ceph_mds_request *req;
1791 	struct rb_node *p;
1792 
1793 	doutc(cl, "mds%d\n", session->s_mds);
1794 	mutex_lock(&mdsc->mutex);
1795 	while (!list_empty(&session->s_unsafe)) {
1796 		req = list_first_entry(&session->s_unsafe,
1797 				       struct ceph_mds_request, r_unsafe_item);
1798 		pr_warn_ratelimited_client(cl, " dropping unsafe request %llu\n",
1799 					   req->r_tid);
1800 		if (req->r_target_inode)
1801 			mapping_set_error(req->r_target_inode->i_mapping, -EIO);
1802 		if (req->r_unsafe_dir)
1803 			mapping_set_error(req->r_unsafe_dir->i_mapping, -EIO);
1804 		__unregister_request(mdsc, req);
1805 	}
1806 	/* zero r_attempts, so kick_requests() will re-send requests */
1807 	p = rb_first(&mdsc->request_tree);
1808 	while (p) {
1809 		req = rb_entry(p, struct ceph_mds_request, r_node);
1810 		p = rb_next(p);
1811 		if (req->r_session &&
1812 		    req->r_session->s_mds == session->s_mds)
1813 			req->r_attempts = 0;
1814 	}
1815 	mutex_unlock(&mdsc->mutex);
1816 }
1817 
1818 /*
1819  * Helper to safely iterate over all caps associated with a session, with
1820  * special care taken to handle a racing __ceph_remove_cap().
1821  *
1822  * Caller must hold session s_mutex.
1823  */
1824 int ceph_iterate_session_caps(struct ceph_mds_session *session,
1825 			      int (*cb)(struct inode *, int mds, void *),
1826 			      void *arg)
1827 {
1828 	struct ceph_client *cl = session->s_mdsc->fsc->client;
1829 	struct list_head *p;
1830 	struct ceph_cap *cap;
1831 	struct inode *inode, *last_inode = NULL;
1832 	struct ceph_cap *old_cap = NULL;
1833 	int ret;
1834 
1835 	doutc(cl, "%p mds%d\n", session, session->s_mds);
1836 	spin_lock(&session->s_cap_lock);
1837 	p = session->s_caps.next;
1838 	while (p != &session->s_caps) {
1839 		int mds;
1840 
1841 		cap = list_entry(p, struct ceph_cap, session_caps);
1842 		inode = igrab(&cap->ci->netfs.inode);
1843 		if (!inode) {
1844 			p = p->next;
1845 			continue;
1846 		}
1847 		session->s_cap_iterator = cap;
1848 		mds = cap->mds;
1849 		spin_unlock(&session->s_cap_lock);
1850 
1851 		if (last_inode) {
1852 			iput(last_inode);
1853 			last_inode = NULL;
1854 		}
1855 		if (old_cap) {
1856 			ceph_put_cap(session->s_mdsc, old_cap);
1857 			old_cap = NULL;
1858 		}
1859 
1860 		ret = cb(inode, mds, arg);
1861 		last_inode = inode;
1862 
1863 		spin_lock(&session->s_cap_lock);
1864 		p = p->next;
1865 		if (!cap->ci) {
1866 			doutc(cl, "finishing cap %p removal\n", cap);
1867 			BUG_ON(cap->session != session);
1868 			cap->session = NULL;
1869 			list_del_init(&cap->session_caps);
1870 			session->s_nr_caps--;
1871 			atomic64_dec(&session->s_mdsc->metric.total_caps);
1872 			if (cap->queue_release)
1873 				__ceph_queue_cap_release(session, cap);
1874 			else
1875 				old_cap = cap;  /* put_cap it w/o locks held */
1876 		}
1877 		if (ret < 0)
1878 			goto out;
1879 	}
1880 	ret = 0;
1881 out:
1882 	session->s_cap_iterator = NULL;
1883 	spin_unlock(&session->s_cap_lock);
1884 
1885 	iput(last_inode);
1886 	if (old_cap)
1887 		ceph_put_cap(session->s_mdsc, old_cap);
1888 
1889 	return ret;
1890 }
1891 
1892 static int remove_session_caps_cb(struct inode *inode, int mds, void *arg)
1893 {
1894 	struct ceph_inode_info *ci = ceph_inode(inode);
1895 	struct ceph_client *cl = ceph_inode_to_client(inode);
1896 	bool invalidate = false;
1897 	struct ceph_cap *cap;
1898 	int iputs = 0;
1899 
1900 	spin_lock(&ci->i_ceph_lock);
1901 	cap = __get_cap_for_mds(ci, mds);
1902 	if (cap) {
1903 		doutc(cl, " removing cap %p, ci is %p, inode is %p\n",
1904 		      cap, ci, &ci->netfs.inode);
1905 
1906 		iputs = ceph_purge_inode_cap(inode, cap, &invalidate);
1907 	}
1908 	spin_unlock(&ci->i_ceph_lock);
1909 
1910 	if (cap)
1911 		wake_up_all(&ci->i_cap_wq);
1912 	if (invalidate)
1913 		ceph_queue_invalidate(inode);
1914 	while (iputs--)
1915 		iput(inode);
1916 	return 0;
1917 }
1918 
1919 /*
1920  * caller must hold session s_mutex
1921  */
1922 static void remove_session_caps(struct ceph_mds_session *session)
1923 {
1924 	struct ceph_fs_client *fsc = session->s_mdsc->fsc;
1925 	struct super_block *sb = fsc->sb;
1926 	LIST_HEAD(dispose);
1927 
1928 	doutc(fsc->client, "on %p\n", session);
1929 	ceph_iterate_session_caps(session, remove_session_caps_cb, fsc);
1930 
1931 	wake_up_all(&fsc->mdsc->cap_flushing_wq);
1932 
1933 	spin_lock(&session->s_cap_lock);
1934 	if (session->s_nr_caps > 0) {
1935 		struct inode *inode;
1936 		struct ceph_cap *cap, *prev = NULL;
1937 		struct ceph_vino vino;
1938 		/*
1939 		 * iterate_session_caps() skips inodes that are being
1940 		 * deleted, we need to wait until deletions are complete.
1941 		 * __wait_on_freeing_inode() is designed for the job,
1942 		 * but it is not exported, so use lookup inode function
1943 		 * to access it.
1944 		 */
1945 		while (!list_empty(&session->s_caps)) {
1946 			cap = list_entry(session->s_caps.next,
1947 					 struct ceph_cap, session_caps);
1948 			if (cap == prev)
1949 				break;
1950 			prev = cap;
1951 			vino = cap->ci->i_vino;
1952 			spin_unlock(&session->s_cap_lock);
1953 
1954 			inode = ceph_find_inode(sb, vino);
1955 			iput(inode);
1956 
1957 			spin_lock(&session->s_cap_lock);
1958 		}
1959 	}
1960 
1961 	// drop cap expires and unlock s_cap_lock
1962 	detach_cap_releases(session, &dispose);
1963 
1964 	BUG_ON(session->s_nr_caps > 0);
1965 	BUG_ON(!list_empty(&session->s_cap_flushing));
1966 	spin_unlock(&session->s_cap_lock);
1967 	dispose_cap_releases(session->s_mdsc, &dispose);
1968 }
1969 
1970 enum {
1971 	RECONNECT,
1972 	RENEWCAPS,
1973 	FORCE_RO,
1974 };
1975 
1976 /*
1977  * wake up any threads waiting on this session's caps.  if the cap is
1978  * old (didn't get renewed on the client reconnect), remove it now.
1979  *
1980  * caller must hold s_mutex.
1981  */
1982 static int wake_up_session_cb(struct inode *inode, int mds, void *arg)
1983 {
1984 	struct ceph_inode_info *ci = ceph_inode(inode);
1985 	unsigned long ev = (unsigned long)arg;
1986 
1987 	if (ev == RECONNECT) {
1988 		spin_lock(&ci->i_ceph_lock);
1989 		ci->i_wanted_max_size = 0;
1990 		ci->i_requested_max_size = 0;
1991 		spin_unlock(&ci->i_ceph_lock);
1992 	} else if (ev == RENEWCAPS) {
1993 		struct ceph_cap *cap;
1994 
1995 		spin_lock(&ci->i_ceph_lock);
1996 		cap = __get_cap_for_mds(ci, mds);
1997 		/* mds did not re-issue stale cap */
1998 		if (cap && cap->cap_gen < atomic_read(&cap->session->s_cap_gen))
1999 			cap->issued = cap->implemented = CEPH_CAP_PIN;
2000 		spin_unlock(&ci->i_ceph_lock);
2001 	} else if (ev == FORCE_RO) {
2002 	}
2003 	wake_up_all(&ci->i_cap_wq);
2004 	return 0;
2005 }
2006 
2007 static void wake_up_session_caps(struct ceph_mds_session *session, int ev)
2008 {
2009 	struct ceph_client *cl = session->s_mdsc->fsc->client;
2010 
2011 	doutc(cl, "session %p mds%d\n", session, session->s_mds);
2012 	ceph_iterate_session_caps(session, wake_up_session_cb,
2013 				  (void *)(unsigned long)ev);
2014 }
2015 
2016 /*
2017  * Send periodic message to MDS renewing all currently held caps.  The
2018  * ack will reset the expiration for all caps from this session.
2019  *
2020  * caller holds s_mutex
2021  */
2022 static int send_renew_caps(struct ceph_mds_client *mdsc,
2023 			   struct ceph_mds_session *session)
2024 {
2025 	struct ceph_client *cl = mdsc->fsc->client;
2026 	struct ceph_msg *msg;
2027 	int state;
2028 
2029 	if (time_after_eq(jiffies, session->s_cap_ttl) &&
2030 	    time_after_eq(session->s_cap_ttl, session->s_renew_requested))
2031 		pr_info_client(cl, "mds%d caps stale\n", session->s_mds);
2032 	session->s_renew_requested = jiffies;
2033 
2034 	/* do not try to renew caps until a recovering mds has reconnected
2035 	 * with its clients. */
2036 	state = ceph_mdsmap_get_state(mdsc->mdsmap, session->s_mds);
2037 	if (state < CEPH_MDS_STATE_RECONNECT) {
2038 		doutc(cl, "ignoring mds%d (%s)\n", session->s_mds,
2039 		      ceph_mds_state_name(state));
2040 		return 0;
2041 	}
2042 
2043 	doutc(cl, "to mds%d (%s)\n", session->s_mds,
2044 	      ceph_mds_state_name(state));
2045 	msg = create_session_full_msg(mdsc, CEPH_SESSION_REQUEST_RENEWCAPS,
2046 				      ++session->s_renew_seq);
2047 	if (IS_ERR(msg))
2048 		return PTR_ERR(msg);
2049 	ceph_con_send(&session->s_con, msg);
2050 	return 0;
2051 }
2052 
2053 static int send_flushmsg_ack(struct ceph_mds_client *mdsc,
2054 			     struct ceph_mds_session *session, u64 seq)
2055 {
2056 	struct ceph_client *cl = mdsc->fsc->client;
2057 	struct ceph_msg *msg;
2058 
2059 	doutc(cl, "to mds%d (%s)s seq %lld\n", session->s_mds,
2060 	      ceph_session_state_name(session->s_state), seq);
2061 	msg = ceph_create_session_msg(CEPH_SESSION_FLUSHMSG_ACK, seq);
2062 	if (!msg)
2063 		return -ENOMEM;
2064 	ceph_con_send(&session->s_con, msg);
2065 	return 0;
2066 }
2067 
2068 
2069 /*
2070  * Note new cap ttl, and any transition from stale -> not stale (fresh?).
2071  *
2072  * Called under session->s_mutex
2073  */
2074 static void renewed_caps(struct ceph_mds_client *mdsc,
2075 			 struct ceph_mds_session *session, int is_renew)
2076 {
2077 	struct ceph_client *cl = mdsc->fsc->client;
2078 	int was_stale;
2079 	int wake = 0;
2080 
2081 	spin_lock(&session->s_cap_lock);
2082 	was_stale = is_renew && time_after_eq(jiffies, session->s_cap_ttl);
2083 
2084 	session->s_cap_ttl = session->s_renew_requested +
2085 		mdsc->mdsmap->m_session_timeout*HZ;
2086 
2087 	if (was_stale) {
2088 		if (time_before(jiffies, session->s_cap_ttl)) {
2089 			pr_info_client(cl, "mds%d caps renewed\n",
2090 				       session->s_mds);
2091 			wake = 1;
2092 		} else {
2093 			pr_info_client(cl, "mds%d caps still stale\n",
2094 				       session->s_mds);
2095 		}
2096 	}
2097 	doutc(cl, "mds%d ttl now %lu, was %s, now %s\n", session->s_mds,
2098 	      session->s_cap_ttl, was_stale ? "stale" : "fresh",
2099 	      time_before(jiffies, session->s_cap_ttl) ? "stale" : "fresh");
2100 	spin_unlock(&session->s_cap_lock);
2101 
2102 	if (wake)
2103 		wake_up_session_caps(session, RENEWCAPS);
2104 }
2105 
2106 /*
2107  * send a session close request
2108  */
2109 static int request_close_session(struct ceph_mds_session *session)
2110 {
2111 	struct ceph_client *cl = session->s_mdsc->fsc->client;
2112 	struct ceph_msg *msg;
2113 
2114 	doutc(cl, "mds%d state %s seq %lld\n", session->s_mds,
2115 	      ceph_session_state_name(session->s_state), session->s_seq);
2116 	msg = ceph_create_session_msg(CEPH_SESSION_REQUEST_CLOSE,
2117 				      session->s_seq);
2118 	if (!msg)
2119 		return -ENOMEM;
2120 	ceph_con_send(&session->s_con, msg);
2121 	return 1;
2122 }
2123 
2124 /*
2125  * Called with s_mutex held.
2126  */
2127 static int __close_session(struct ceph_mds_client *mdsc,
2128 			 struct ceph_mds_session *session)
2129 {
2130 	if (session->s_state >= CEPH_MDS_SESSION_CLOSING)
2131 		return 0;
2132 	session->s_state = CEPH_MDS_SESSION_CLOSING;
2133 	return request_close_session(session);
2134 }
2135 
2136 static bool drop_negative_children(struct dentry *dentry)
2137 {
2138 	struct dentry *child;
2139 	bool all_negative = true;
2140 
2141 	if (!d_is_dir(dentry))
2142 		goto out;
2143 
2144 	spin_lock(&dentry->d_lock);
2145 	hlist_for_each_entry(child, &dentry->d_children, d_sib) {
2146 		if (d_really_is_positive(child)) {
2147 			all_negative = false;
2148 			break;
2149 		}
2150 	}
2151 	spin_unlock(&dentry->d_lock);
2152 
2153 	if (all_negative)
2154 		shrink_dcache_parent(dentry);
2155 out:
2156 	return all_negative;
2157 }
2158 
2159 /*
2160  * Trim old(er) caps.
2161  *
2162  * Because we can't cache an inode without one or more caps, we do
2163  * this indirectly: if a cap is unused, we prune its aliases, at which
2164  * point the inode will hopefully get dropped to.
2165  *
2166  * Yes, this is a bit sloppy.  Our only real goal here is to respond to
2167  * memory pressure from the MDS, though, so it needn't be perfect.
2168  */
2169 static int trim_caps_cb(struct inode *inode, int mds, void *arg)
2170 {
2171 	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
2172 	struct ceph_client *cl = mdsc->fsc->client;
2173 	int *remaining = arg;
2174 	struct ceph_inode_info *ci = ceph_inode(inode);
2175 	int used, wanted, oissued, mine;
2176 	struct ceph_cap *cap;
2177 
2178 	if (*remaining <= 0)
2179 		return -1;
2180 
2181 	spin_lock(&ci->i_ceph_lock);
2182 	cap = __get_cap_for_mds(ci, mds);
2183 	if (!cap) {
2184 		spin_unlock(&ci->i_ceph_lock);
2185 		return 0;
2186 	}
2187 	mine = cap->issued | cap->implemented;
2188 	used = __ceph_caps_used(ci);
2189 	wanted = __ceph_caps_file_wanted(ci);
2190 	oissued = __ceph_caps_issued_other(ci, cap);
2191 
2192 	doutc(cl, "%p %llx.%llx cap %p mine %s oissued %s used %s wanted %s\n",
2193 	      inode, ceph_vinop(inode), cap, ceph_cap_string(mine),
2194 	      ceph_cap_string(oissued), ceph_cap_string(used),
2195 	      ceph_cap_string(wanted));
2196 	if (cap == ci->i_auth_cap) {
2197 		if (ci->i_dirty_caps || ci->i_flushing_caps ||
2198 		    !list_empty(&ci->i_cap_snaps))
2199 			goto out;
2200 		if ((used | wanted) & CEPH_CAP_ANY_WR)
2201 			goto out;
2202 		/* Note: it's possible that i_filelock_ref becomes non-zero
2203 		 * after dropping auth caps. It doesn't hurt because reply
2204 		 * of lock mds request will re-add auth caps. */
2205 		if (atomic_read(&ci->i_filelock_ref) > 0)
2206 			goto out;
2207 	}
2208 	/* The inode has cached pages, but it's no longer used.
2209 	 * we can safely drop it */
2210 	if (S_ISREG(inode->i_mode) &&
2211 	    wanted == 0 && used == CEPH_CAP_FILE_CACHE &&
2212 	    !(oissued & CEPH_CAP_FILE_CACHE)) {
2213 	  used = 0;
2214 	  oissued = 0;
2215 	}
2216 	if ((used | wanted) & ~oissued & mine)
2217 		goto out;   /* we need these caps */
2218 
2219 	if (oissued) {
2220 		/* we aren't the only cap.. just remove us */
2221 		ceph_remove_cap(mdsc, cap, true);
2222 		(*remaining)--;
2223 	} else {
2224 		struct dentry *dentry;
2225 		/* try dropping referring dentries */
2226 		spin_unlock(&ci->i_ceph_lock);
2227 		dentry = d_find_any_alias(inode);
2228 		if (dentry && drop_negative_children(dentry)) {
2229 			int count;
2230 			dput(dentry);
2231 			d_prune_aliases(inode);
2232 			count = atomic_read(&inode->i_count);
2233 			if (count == 1)
2234 				(*remaining)--;
2235 			doutc(cl, "%p %llx.%llx cap %p pruned, count now %d\n",
2236 			      inode, ceph_vinop(inode), cap, count);
2237 		} else {
2238 			dput(dentry);
2239 		}
2240 		return 0;
2241 	}
2242 
2243 out:
2244 	spin_unlock(&ci->i_ceph_lock);
2245 	return 0;
2246 }
2247 
2248 /*
2249  * Trim session cap count down to some max number.
2250  */
2251 int ceph_trim_caps(struct ceph_mds_client *mdsc,
2252 		   struct ceph_mds_session *session,
2253 		   int max_caps)
2254 {
2255 	struct ceph_client *cl = mdsc->fsc->client;
2256 	int trim_caps = session->s_nr_caps - max_caps;
2257 
2258 	doutc(cl, "mds%d start: %d / %d, trim %d\n", session->s_mds,
2259 	      session->s_nr_caps, max_caps, trim_caps);
2260 	if (trim_caps > 0) {
2261 		int remaining = trim_caps;
2262 
2263 		ceph_iterate_session_caps(session, trim_caps_cb, &remaining);
2264 		doutc(cl, "mds%d done: %d / %d, trimmed %d\n",
2265 		      session->s_mds, session->s_nr_caps, max_caps,
2266 		      trim_caps - remaining);
2267 	}
2268 
2269 	ceph_flush_cap_releases(mdsc, session);
2270 	return 0;
2271 }
2272 
2273 static int check_caps_flush(struct ceph_mds_client *mdsc,
2274 			    u64 want_flush_tid)
2275 {
2276 	struct ceph_client *cl = mdsc->fsc->client;
2277 	int ret = 1;
2278 
2279 	spin_lock(&mdsc->cap_dirty_lock);
2280 	if (!list_empty(&mdsc->cap_flush_list)) {
2281 		struct ceph_cap_flush *cf =
2282 			list_first_entry(&mdsc->cap_flush_list,
2283 					 struct ceph_cap_flush, g_list);
2284 		if (cf->tid <= want_flush_tid) {
2285 			doutc(cl, "still flushing tid %llu <= %llu\n",
2286 			      cf->tid, want_flush_tid);
2287 			ret = 0;
2288 		}
2289 	}
2290 	spin_unlock(&mdsc->cap_dirty_lock);
2291 	return ret;
2292 }
2293 
2294 /*
2295  * flush all dirty inode data to disk.
2296  *
2297  * returns true if we've flushed through want_flush_tid
2298  */
2299 static void wait_caps_flush(struct ceph_mds_client *mdsc,
2300 			    u64 want_flush_tid)
2301 {
2302 	struct ceph_client *cl = mdsc->fsc->client;
2303 
2304 	doutc(cl, "want %llu\n", want_flush_tid);
2305 
2306 	wait_event(mdsc->cap_flushing_wq,
2307 		   check_caps_flush(mdsc, want_flush_tid));
2308 
2309 	doutc(cl, "ok, flushed thru %llu\n", want_flush_tid);
2310 }
2311 
2312 /*
2313  * called under s_mutex
2314  */
2315 static void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
2316 				   struct ceph_mds_session *session)
2317 {
2318 	struct ceph_client *cl = mdsc->fsc->client;
2319 	struct ceph_msg *msg = NULL;
2320 	struct ceph_mds_cap_release *head;
2321 	struct ceph_mds_cap_item *item;
2322 	struct ceph_osd_client *osdc = &mdsc->fsc->client->osdc;
2323 	struct ceph_cap *cap;
2324 	LIST_HEAD(tmp_list);
2325 	int num_cap_releases;
2326 	__le32	barrier, *cap_barrier;
2327 
2328 	down_read(&osdc->lock);
2329 	barrier = cpu_to_le32(osdc->epoch_barrier);
2330 	up_read(&osdc->lock);
2331 
2332 	spin_lock(&session->s_cap_lock);
2333 again:
2334 	list_splice_init(&session->s_cap_releases, &tmp_list);
2335 	num_cap_releases = session->s_num_cap_releases;
2336 	session->s_num_cap_releases = 0;
2337 	spin_unlock(&session->s_cap_lock);
2338 
2339 	while (!list_empty(&tmp_list)) {
2340 		if (!msg) {
2341 			msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPRELEASE,
2342 					PAGE_SIZE, GFP_NOFS, false);
2343 			if (!msg)
2344 				goto out_err;
2345 			head = msg->front.iov_base;
2346 			head->num = cpu_to_le32(0);
2347 			msg->front.iov_len = sizeof(*head);
2348 
2349 			msg->hdr.version = cpu_to_le16(2);
2350 			msg->hdr.compat_version = cpu_to_le16(1);
2351 		}
2352 
2353 		cap = list_first_entry(&tmp_list, struct ceph_cap,
2354 					session_caps);
2355 		list_del(&cap->session_caps);
2356 		num_cap_releases--;
2357 
2358 		head = msg->front.iov_base;
2359 		put_unaligned_le32(get_unaligned_le32(&head->num) + 1,
2360 				   &head->num);
2361 		item = msg->front.iov_base + msg->front.iov_len;
2362 		item->ino = cpu_to_le64(cap->cap_ino);
2363 		item->cap_id = cpu_to_le64(cap->cap_id);
2364 		item->migrate_seq = cpu_to_le32(cap->mseq);
2365 		item->seq = cpu_to_le32(cap->issue_seq);
2366 		msg->front.iov_len += sizeof(*item);
2367 
2368 		ceph_put_cap(mdsc, cap);
2369 
2370 		if (le32_to_cpu(head->num) == CEPH_CAPS_PER_RELEASE) {
2371 			// Append cap_barrier field
2372 			cap_barrier = msg->front.iov_base + msg->front.iov_len;
2373 			*cap_barrier = barrier;
2374 			msg->front.iov_len += sizeof(*cap_barrier);
2375 
2376 			msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
2377 			doutc(cl, "mds%d %p\n", session->s_mds, msg);
2378 			ceph_con_send(&session->s_con, msg);
2379 			msg = NULL;
2380 		}
2381 	}
2382 
2383 	BUG_ON(num_cap_releases != 0);
2384 
2385 	spin_lock(&session->s_cap_lock);
2386 	if (!list_empty(&session->s_cap_releases))
2387 		goto again;
2388 	spin_unlock(&session->s_cap_lock);
2389 
2390 	if (msg) {
2391 		// Append cap_barrier field
2392 		cap_barrier = msg->front.iov_base + msg->front.iov_len;
2393 		*cap_barrier = barrier;
2394 		msg->front.iov_len += sizeof(*cap_barrier);
2395 
2396 		msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
2397 		doutc(cl, "mds%d %p\n", session->s_mds, msg);
2398 		ceph_con_send(&session->s_con, msg);
2399 	}
2400 	return;
2401 out_err:
2402 	pr_err_client(cl, "mds%d, failed to allocate message\n",
2403 		      session->s_mds);
2404 	spin_lock(&session->s_cap_lock);
2405 	list_splice(&tmp_list, &session->s_cap_releases);
2406 	session->s_num_cap_releases += num_cap_releases;
2407 	spin_unlock(&session->s_cap_lock);
2408 }
2409 
2410 static void ceph_cap_release_work(struct work_struct *work)
2411 {
2412 	struct ceph_mds_session *session =
2413 		container_of(work, struct ceph_mds_session, s_cap_release_work);
2414 
2415 	mutex_lock(&session->s_mutex);
2416 	if (session->s_state == CEPH_MDS_SESSION_OPEN ||
2417 	    session->s_state == CEPH_MDS_SESSION_HUNG)
2418 		ceph_send_cap_releases(session->s_mdsc, session);
2419 	mutex_unlock(&session->s_mutex);
2420 	ceph_put_mds_session(session);
2421 }
2422 
2423 void ceph_flush_cap_releases(struct ceph_mds_client *mdsc,
2424 		             struct ceph_mds_session *session)
2425 {
2426 	struct ceph_client *cl = mdsc->fsc->client;
2427 	if (mdsc->stopping)
2428 		return;
2429 
2430 	ceph_get_mds_session(session);
2431 	if (queue_work(mdsc->fsc->cap_wq,
2432 		       &session->s_cap_release_work)) {
2433 		doutc(cl, "cap release work queued\n");
2434 	} else {
2435 		ceph_put_mds_session(session);
2436 		doutc(cl, "failed to queue cap release work\n");
2437 	}
2438 }
2439 
2440 /*
2441  * caller holds session->s_cap_lock
2442  */
2443 void __ceph_queue_cap_release(struct ceph_mds_session *session,
2444 			      struct ceph_cap *cap)
2445 {
2446 	list_add_tail(&cap->session_caps, &session->s_cap_releases);
2447 	session->s_num_cap_releases++;
2448 
2449 	if (!(session->s_num_cap_releases % CEPH_CAPS_PER_RELEASE))
2450 		ceph_flush_cap_releases(session->s_mdsc, session);
2451 }
2452 
2453 static void ceph_cap_reclaim_work(struct work_struct *work)
2454 {
2455 	struct ceph_mds_client *mdsc =
2456 		container_of(work, struct ceph_mds_client, cap_reclaim_work);
2457 	int ret = ceph_trim_dentries(mdsc);
2458 	if (ret == -EAGAIN)
2459 		ceph_queue_cap_reclaim_work(mdsc);
2460 }
2461 
2462 void ceph_queue_cap_reclaim_work(struct ceph_mds_client *mdsc)
2463 {
2464 	struct ceph_client *cl = mdsc->fsc->client;
2465 	if (mdsc->stopping)
2466 		return;
2467 
2468         if (queue_work(mdsc->fsc->cap_wq, &mdsc->cap_reclaim_work)) {
2469                 doutc(cl, "caps reclaim work queued\n");
2470         } else {
2471                 doutc(cl, "failed to queue caps release work\n");
2472         }
2473 }
2474 
2475 void ceph_reclaim_caps_nr(struct ceph_mds_client *mdsc, int nr)
2476 {
2477 	int val;
2478 	if (!nr)
2479 		return;
2480 	val = atomic_add_return(nr, &mdsc->cap_reclaim_pending);
2481 	if ((val % CEPH_CAPS_PER_RELEASE) < nr) {
2482 		atomic_set(&mdsc->cap_reclaim_pending, 0);
2483 		ceph_queue_cap_reclaim_work(mdsc);
2484 	}
2485 }
2486 
2487 /*
2488  * requests
2489  */
2490 
2491 int ceph_alloc_readdir_reply_buffer(struct ceph_mds_request *req,
2492 				    struct inode *dir)
2493 {
2494 	struct ceph_inode_info *ci = ceph_inode(dir);
2495 	struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
2496 	struct ceph_mount_options *opt = req->r_mdsc->fsc->mount_options;
2497 	size_t size = sizeof(struct ceph_mds_reply_dir_entry);
2498 	unsigned int num_entries;
2499 	int order;
2500 
2501 	spin_lock(&ci->i_ceph_lock);
2502 	num_entries = ci->i_files + ci->i_subdirs;
2503 	spin_unlock(&ci->i_ceph_lock);
2504 	num_entries = max(num_entries, 1U);
2505 	num_entries = min(num_entries, opt->max_readdir);
2506 
2507 	order = get_order(size * num_entries);
2508 	while (order >= 0) {
2509 		rinfo->dir_entries = (void*)__get_free_pages(GFP_KERNEL |
2510 							     __GFP_NOWARN |
2511 							     __GFP_ZERO,
2512 							     order);
2513 		if (rinfo->dir_entries)
2514 			break;
2515 		order--;
2516 	}
2517 	if (!rinfo->dir_entries)
2518 		return -ENOMEM;
2519 
2520 	num_entries = (PAGE_SIZE << order) / size;
2521 	num_entries = min(num_entries, opt->max_readdir);
2522 
2523 	rinfo->dir_buf_size = PAGE_SIZE << order;
2524 	req->r_num_caps = num_entries + 1;
2525 	req->r_args.readdir.max_entries = cpu_to_le32(num_entries);
2526 	req->r_args.readdir.max_bytes = cpu_to_le32(opt->max_readdir_bytes);
2527 	return 0;
2528 }
2529 
2530 /*
2531  * Create an mds request.
2532  */
2533 struct ceph_mds_request *
2534 ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode)
2535 {
2536 	struct ceph_mds_request *req;
2537 
2538 	req = kmem_cache_zalloc(ceph_mds_request_cachep, GFP_NOFS);
2539 	if (!req)
2540 		return ERR_PTR(-ENOMEM);
2541 
2542 	mutex_init(&req->r_fill_mutex);
2543 	req->r_mdsc = mdsc;
2544 	req->r_started = jiffies;
2545 	req->r_start_latency = ktime_get();
2546 	req->r_resend_mds = -1;
2547 	INIT_LIST_HEAD(&req->r_unsafe_dir_item);
2548 	INIT_LIST_HEAD(&req->r_unsafe_target_item);
2549 	req->r_fmode = -1;
2550 	req->r_feature_needed = -1;
2551 	kref_init(&req->r_kref);
2552 	RB_CLEAR_NODE(&req->r_node);
2553 	INIT_LIST_HEAD(&req->r_wait);
2554 	init_completion(&req->r_completion);
2555 	init_completion(&req->r_safe_completion);
2556 	INIT_LIST_HEAD(&req->r_unsafe_item);
2557 
2558 	ktime_get_coarse_real_ts64(&req->r_stamp);
2559 
2560 	req->r_op = op;
2561 	req->r_direct_mode = mode;
2562 	return req;
2563 }
2564 
2565 /*
2566  * return oldest (lowest) request, tid in request tree, 0 if none.
2567  *
2568  * called under mdsc->mutex.
2569  */
2570 static struct ceph_mds_request *__get_oldest_req(struct ceph_mds_client *mdsc)
2571 {
2572 	if (RB_EMPTY_ROOT(&mdsc->request_tree))
2573 		return NULL;
2574 	return rb_entry(rb_first(&mdsc->request_tree),
2575 			struct ceph_mds_request, r_node);
2576 }
2577 
2578 static inline  u64 __get_oldest_tid(struct ceph_mds_client *mdsc)
2579 {
2580 	return mdsc->oldest_tid;
2581 }
2582 
2583 #if IS_ENABLED(CONFIG_FS_ENCRYPTION)
2584 static u8 *get_fscrypt_altname(const struct ceph_mds_request *req, u32 *plen)
2585 {
2586 	struct inode *dir = req->r_parent;
2587 	struct dentry *dentry = req->r_dentry;
2588 	u8 *cryptbuf = NULL;
2589 	u32 len = 0;
2590 	int ret = 0;
2591 
2592 	/* only encode if we have parent and dentry */
2593 	if (!dir || !dentry)
2594 		goto success;
2595 
2596 	/* No-op unless this is encrypted */
2597 	if (!IS_ENCRYPTED(dir))
2598 		goto success;
2599 
2600 	ret = ceph_fscrypt_prepare_readdir(dir);
2601 	if (ret < 0)
2602 		return ERR_PTR(ret);
2603 
2604 	/* No key? Just ignore it. */
2605 	if (!fscrypt_has_encryption_key(dir))
2606 		goto success;
2607 
2608 	if (!fscrypt_fname_encrypted_size(dir, dentry->d_name.len, NAME_MAX,
2609 					  &len)) {
2610 		WARN_ON_ONCE(1);
2611 		return ERR_PTR(-ENAMETOOLONG);
2612 	}
2613 
2614 	/* No need to append altname if name is short enough */
2615 	if (len <= CEPH_NOHASH_NAME_MAX) {
2616 		len = 0;
2617 		goto success;
2618 	}
2619 
2620 	cryptbuf = kmalloc(len, GFP_KERNEL);
2621 	if (!cryptbuf)
2622 		return ERR_PTR(-ENOMEM);
2623 
2624 	ret = fscrypt_fname_encrypt(dir, &dentry->d_name, cryptbuf, len);
2625 	if (ret) {
2626 		kfree(cryptbuf);
2627 		return ERR_PTR(ret);
2628 	}
2629 success:
2630 	*plen = len;
2631 	return cryptbuf;
2632 }
2633 #else
2634 static u8 *get_fscrypt_altname(const struct ceph_mds_request *req, u32 *plen)
2635 {
2636 	*plen = 0;
2637 	return NULL;
2638 }
2639 #endif
2640 
2641 /**
2642  * ceph_mdsc_build_path - build a path string to a given dentry
2643  * @mdsc: mds client
2644  * @dentry: dentry to which path should be built
2645  * @plen: returned length of string
2646  * @pbase: returned base inode number
2647  * @for_wire: is this path going to be sent to the MDS?
2648  *
2649  * Build a string that represents the path to the dentry. This is mostly called
2650  * for two different purposes:
2651  *
2652  * 1) we need to build a path string to send to the MDS (for_wire == true)
2653  * 2) we need a path string for local presentation (e.g. debugfs)
2654  *    (for_wire == false)
2655  *
2656  * The path is built in reverse, starting with the dentry. Walk back up toward
2657  * the root, building the path until the first non-snapped inode is reached
2658  * (for_wire) or the root inode is reached (!for_wire).
2659  *
2660  * Encode hidden .snap dirs as a double /, i.e.
2661  *   foo/.snap/bar -> foo//bar
2662  */
2663 char *ceph_mdsc_build_path(struct ceph_mds_client *mdsc, struct dentry *dentry,
2664 			   int *plen, u64 *pbase, int for_wire)
2665 {
2666 	struct ceph_client *cl = mdsc->fsc->client;
2667 	struct dentry *cur;
2668 	struct inode *inode;
2669 	char *path;
2670 	int pos;
2671 	unsigned seq;
2672 	u64 base;
2673 
2674 	if (!dentry)
2675 		return ERR_PTR(-EINVAL);
2676 
2677 	path = __getname();
2678 	if (!path)
2679 		return ERR_PTR(-ENOMEM);
2680 retry:
2681 	pos = PATH_MAX - 1;
2682 	path[pos] = '\0';
2683 
2684 	seq = read_seqbegin(&rename_lock);
2685 	cur = dget(dentry);
2686 	for (;;) {
2687 		struct dentry *parent;
2688 
2689 		spin_lock(&cur->d_lock);
2690 		inode = d_inode(cur);
2691 		if (inode && ceph_snap(inode) == CEPH_SNAPDIR) {
2692 			doutc(cl, "path+%d: %p SNAPDIR\n", pos, cur);
2693 			spin_unlock(&cur->d_lock);
2694 			parent = dget_parent(cur);
2695 		} else if (for_wire && inode && dentry != cur &&
2696 			   ceph_snap(inode) == CEPH_NOSNAP) {
2697 			spin_unlock(&cur->d_lock);
2698 			pos++; /* get rid of any prepended '/' */
2699 			break;
2700 		} else if (!for_wire || !IS_ENCRYPTED(d_inode(cur->d_parent))) {
2701 			pos -= cur->d_name.len;
2702 			if (pos < 0) {
2703 				spin_unlock(&cur->d_lock);
2704 				break;
2705 			}
2706 			memcpy(path + pos, cur->d_name.name, cur->d_name.len);
2707 			spin_unlock(&cur->d_lock);
2708 			parent = dget_parent(cur);
2709 		} else {
2710 			int len, ret;
2711 			char buf[NAME_MAX];
2712 
2713 			/*
2714 			 * Proactively copy name into buf, in case we need to
2715 			 * present it as-is.
2716 			 */
2717 			memcpy(buf, cur->d_name.name, cur->d_name.len);
2718 			len = cur->d_name.len;
2719 			spin_unlock(&cur->d_lock);
2720 			parent = dget_parent(cur);
2721 
2722 			ret = ceph_fscrypt_prepare_readdir(d_inode(parent));
2723 			if (ret < 0) {
2724 				dput(parent);
2725 				dput(cur);
2726 				return ERR_PTR(ret);
2727 			}
2728 
2729 			if (fscrypt_has_encryption_key(d_inode(parent))) {
2730 				len = ceph_encode_encrypted_fname(d_inode(parent),
2731 								  cur, buf);
2732 				if (len < 0) {
2733 					dput(parent);
2734 					dput(cur);
2735 					return ERR_PTR(len);
2736 				}
2737 			}
2738 			pos -= len;
2739 			if (pos < 0) {
2740 				dput(parent);
2741 				break;
2742 			}
2743 			memcpy(path + pos, buf, len);
2744 		}
2745 		dput(cur);
2746 		cur = parent;
2747 
2748 		/* Are we at the root? */
2749 		if (IS_ROOT(cur))
2750 			break;
2751 
2752 		/* Are we out of buffer? */
2753 		if (--pos < 0)
2754 			break;
2755 
2756 		path[pos] = '/';
2757 	}
2758 	inode = d_inode(cur);
2759 	base = inode ? ceph_ino(inode) : 0;
2760 	dput(cur);
2761 
2762 	if (read_seqretry(&rename_lock, seq))
2763 		goto retry;
2764 
2765 	if (pos < 0) {
2766 		/*
2767 		 * A rename didn't occur, but somehow we didn't end up where
2768 		 * we thought we would. Throw a warning and try again.
2769 		 */
2770 		pr_warn_client(cl, "did not end path lookup where expected (pos = %d)\n",
2771 			       pos);
2772 		goto retry;
2773 	}
2774 
2775 	*pbase = base;
2776 	*plen = PATH_MAX - 1 - pos;
2777 	doutc(cl, "on %p %d built %llx '%.*s'\n", dentry, d_count(dentry),
2778 	      base, *plen, path + pos);
2779 	return path + pos;
2780 }
2781 
2782 static int build_dentry_path(struct ceph_mds_client *mdsc, struct dentry *dentry,
2783 			     struct inode *dir, const char **ppath, int *ppathlen,
2784 			     u64 *pino, bool *pfreepath, bool parent_locked)
2785 {
2786 	char *path;
2787 
2788 	rcu_read_lock();
2789 	if (!dir)
2790 		dir = d_inode_rcu(dentry->d_parent);
2791 	if (dir && parent_locked && ceph_snap(dir) == CEPH_NOSNAP &&
2792 	    !IS_ENCRYPTED(dir)) {
2793 		*pino = ceph_ino(dir);
2794 		rcu_read_unlock();
2795 		*ppath = dentry->d_name.name;
2796 		*ppathlen = dentry->d_name.len;
2797 		return 0;
2798 	}
2799 	rcu_read_unlock();
2800 	path = ceph_mdsc_build_path(mdsc, dentry, ppathlen, pino, 1);
2801 	if (IS_ERR(path))
2802 		return PTR_ERR(path);
2803 	*ppath = path;
2804 	*pfreepath = true;
2805 	return 0;
2806 }
2807 
2808 static int build_inode_path(struct inode *inode,
2809 			    const char **ppath, int *ppathlen, u64 *pino,
2810 			    bool *pfreepath)
2811 {
2812 	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
2813 	struct dentry *dentry;
2814 	char *path;
2815 
2816 	if (ceph_snap(inode) == CEPH_NOSNAP) {
2817 		*pino = ceph_ino(inode);
2818 		*ppathlen = 0;
2819 		return 0;
2820 	}
2821 	dentry = d_find_alias(inode);
2822 	path = ceph_mdsc_build_path(mdsc, dentry, ppathlen, pino, 1);
2823 	dput(dentry);
2824 	if (IS_ERR(path))
2825 		return PTR_ERR(path);
2826 	*ppath = path;
2827 	*pfreepath = true;
2828 	return 0;
2829 }
2830 
2831 /*
2832  * request arguments may be specified via an inode *, a dentry *, or
2833  * an explicit ino+path.
2834  */
2835 static int set_request_path_attr(struct ceph_mds_client *mdsc, struct inode *rinode,
2836 				 struct dentry *rdentry, struct inode *rdiri,
2837 				 const char *rpath, u64 rino, const char **ppath,
2838 				 int *pathlen, u64 *ino, bool *freepath,
2839 				 bool parent_locked)
2840 {
2841 	struct ceph_client *cl = mdsc->fsc->client;
2842 	int r = 0;
2843 
2844 	if (rinode) {
2845 		r = build_inode_path(rinode, ppath, pathlen, ino, freepath);
2846 		doutc(cl, " inode %p %llx.%llx\n", rinode, ceph_ino(rinode),
2847 		      ceph_snap(rinode));
2848 	} else if (rdentry) {
2849 		r = build_dentry_path(mdsc, rdentry, rdiri, ppath, pathlen, ino,
2850 					freepath, parent_locked);
2851 		doutc(cl, " dentry %p %llx/%.*s\n", rdentry, *ino, *pathlen, *ppath);
2852 	} else if (rpath || rino) {
2853 		*ino = rino;
2854 		*ppath = rpath;
2855 		*pathlen = rpath ? strlen(rpath) : 0;
2856 		doutc(cl, " path %.*s\n", *pathlen, rpath);
2857 	}
2858 
2859 	return r;
2860 }
2861 
2862 static void encode_mclientrequest_tail(void **p,
2863 				       const struct ceph_mds_request *req)
2864 {
2865 	struct ceph_timespec ts;
2866 	int i;
2867 
2868 	ceph_encode_timespec64(&ts, &req->r_stamp);
2869 	ceph_encode_copy(p, &ts, sizeof(ts));
2870 
2871 	/* v4: gid_list */
2872 	ceph_encode_32(p, req->r_cred->group_info->ngroups);
2873 	for (i = 0; i < req->r_cred->group_info->ngroups; i++)
2874 		ceph_encode_64(p, from_kgid(&init_user_ns,
2875 					    req->r_cred->group_info->gid[i]));
2876 
2877 	/* v5: altname */
2878 	ceph_encode_32(p, req->r_altname_len);
2879 	ceph_encode_copy(p, req->r_altname, req->r_altname_len);
2880 
2881 	/* v6: fscrypt_auth and fscrypt_file */
2882 	if (req->r_fscrypt_auth) {
2883 		u32 authlen = ceph_fscrypt_auth_len(req->r_fscrypt_auth);
2884 
2885 		ceph_encode_32(p, authlen);
2886 		ceph_encode_copy(p, req->r_fscrypt_auth, authlen);
2887 	} else {
2888 		ceph_encode_32(p, 0);
2889 	}
2890 	if (test_bit(CEPH_MDS_R_FSCRYPT_FILE, &req->r_req_flags)) {
2891 		ceph_encode_32(p, sizeof(__le64));
2892 		ceph_encode_64(p, req->r_fscrypt_file);
2893 	} else {
2894 		ceph_encode_32(p, 0);
2895 	}
2896 }
2897 
2898 static inline u16 mds_supported_head_version(struct ceph_mds_session *session)
2899 {
2900 	if (!test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD, &session->s_features))
2901 		return 1;
2902 
2903 	if (!test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features))
2904 		return 2;
2905 
2906 	return CEPH_MDS_REQUEST_HEAD_VERSION;
2907 }
2908 
2909 static struct ceph_mds_request_head_legacy *
2910 find_legacy_request_head(void *p, u64 features)
2911 {
2912 	bool legacy = !(features & CEPH_FEATURE_FS_BTIME);
2913 	struct ceph_mds_request_head_old *ohead;
2914 
2915 	if (legacy)
2916 		return (struct ceph_mds_request_head_legacy *)p;
2917 	ohead = (struct ceph_mds_request_head_old *)p;
2918 	return (struct ceph_mds_request_head_legacy *)&ohead->oldest_client_tid;
2919 }
2920 
2921 /*
2922  * called under mdsc->mutex
2923  */
2924 static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
2925 					       struct ceph_mds_request *req,
2926 					       bool drop_cap_releases)
2927 {
2928 	int mds = session->s_mds;
2929 	struct ceph_mds_client *mdsc = session->s_mdsc;
2930 	struct ceph_client *cl = mdsc->fsc->client;
2931 	struct ceph_msg *msg;
2932 	struct ceph_mds_request_head_legacy *lhead;
2933 	const char *path1 = NULL;
2934 	const char *path2 = NULL;
2935 	u64 ino1 = 0, ino2 = 0;
2936 	int pathlen1 = 0, pathlen2 = 0;
2937 	bool freepath1 = false, freepath2 = false;
2938 	struct dentry *old_dentry = NULL;
2939 	int len;
2940 	u16 releases;
2941 	void *p, *end;
2942 	int ret;
2943 	bool legacy = !(session->s_con.peer_features & CEPH_FEATURE_FS_BTIME);
2944 	u16 request_head_version = mds_supported_head_version(session);
2945 	kuid_t caller_fsuid = req->r_cred->fsuid;
2946 	kgid_t caller_fsgid = req->r_cred->fsgid;
2947 
2948 	ret = set_request_path_attr(mdsc, req->r_inode, req->r_dentry,
2949 			      req->r_parent, req->r_path1, req->r_ino1.ino,
2950 			      &path1, &pathlen1, &ino1, &freepath1,
2951 			      test_bit(CEPH_MDS_R_PARENT_LOCKED,
2952 					&req->r_req_flags));
2953 	if (ret < 0) {
2954 		msg = ERR_PTR(ret);
2955 		goto out;
2956 	}
2957 
2958 	/* If r_old_dentry is set, then assume that its parent is locked */
2959 	if (req->r_old_dentry &&
2960 	    !(req->r_old_dentry->d_flags & DCACHE_DISCONNECTED))
2961 		old_dentry = req->r_old_dentry;
2962 	ret = set_request_path_attr(mdsc, NULL, old_dentry,
2963 			      req->r_old_dentry_dir,
2964 			      req->r_path2, req->r_ino2.ino,
2965 			      &path2, &pathlen2, &ino2, &freepath2, true);
2966 	if (ret < 0) {
2967 		msg = ERR_PTR(ret);
2968 		goto out_free1;
2969 	}
2970 
2971 	req->r_altname = get_fscrypt_altname(req, &req->r_altname_len);
2972 	if (IS_ERR(req->r_altname)) {
2973 		msg = ERR_CAST(req->r_altname);
2974 		req->r_altname = NULL;
2975 		goto out_free2;
2976 	}
2977 
2978 	/*
2979 	 * For old cephs without supporting the 32bit retry/fwd feature
2980 	 * it will copy the raw memories directly when decoding the
2981 	 * requests. While new cephs will decode the head depending the
2982 	 * version member, so we need to make sure it will be compatible
2983 	 * with them both.
2984 	 */
2985 	if (legacy)
2986 		len = sizeof(struct ceph_mds_request_head_legacy);
2987 	else if (request_head_version == 1)
2988 		len = sizeof(struct ceph_mds_request_head_old);
2989 	else if (request_head_version == 2)
2990 		len = offsetofend(struct ceph_mds_request_head, ext_num_fwd);
2991 	else
2992 		len = sizeof(struct ceph_mds_request_head);
2993 
2994 	/* filepaths */
2995 	len += 2 * (1 + sizeof(u32) + sizeof(u64));
2996 	len += pathlen1 + pathlen2;
2997 
2998 	/* cap releases */
2999 	len += sizeof(struct ceph_mds_request_release) *
3000 		(!!req->r_inode_drop + !!req->r_dentry_drop +
3001 		 !!req->r_old_inode_drop + !!req->r_old_dentry_drop);
3002 
3003 	if (req->r_dentry_drop)
3004 		len += pathlen1;
3005 	if (req->r_old_dentry_drop)
3006 		len += pathlen2;
3007 
3008 	/* MClientRequest tail */
3009 
3010 	/* req->r_stamp */
3011 	len += sizeof(struct ceph_timespec);
3012 
3013 	/* gid list */
3014 	len += sizeof(u32) + (sizeof(u64) * req->r_cred->group_info->ngroups);
3015 
3016 	/* alternate name */
3017 	len += sizeof(u32) + req->r_altname_len;
3018 
3019 	/* fscrypt_auth */
3020 	len += sizeof(u32); // fscrypt_auth
3021 	if (req->r_fscrypt_auth)
3022 		len += ceph_fscrypt_auth_len(req->r_fscrypt_auth);
3023 
3024 	/* fscrypt_file */
3025 	len += sizeof(u32);
3026 	if (test_bit(CEPH_MDS_R_FSCRYPT_FILE, &req->r_req_flags))
3027 		len += sizeof(__le64);
3028 
3029 	msg = ceph_msg_new2(CEPH_MSG_CLIENT_REQUEST, len, 1, GFP_NOFS, false);
3030 	if (!msg) {
3031 		msg = ERR_PTR(-ENOMEM);
3032 		goto out_free2;
3033 	}
3034 
3035 	msg->hdr.tid = cpu_to_le64(req->r_tid);
3036 
3037 	lhead = find_legacy_request_head(msg->front.iov_base,
3038 					 session->s_con.peer_features);
3039 
3040 	if ((req->r_mnt_idmap != &nop_mnt_idmap) &&
3041 	    !test_bit(CEPHFS_FEATURE_HAS_OWNER_UIDGID, &session->s_features)) {
3042 		WARN_ON_ONCE(!IS_CEPH_MDS_OP_NEWINODE(req->r_op));
3043 
3044 		if (enable_unsafe_idmap) {
3045 			pr_warn_once_client(cl,
3046 				"idmapped mount is used and CEPHFS_FEATURE_HAS_OWNER_UIDGID"
3047 				" is not supported by MDS. UID/GID-based restrictions may"
3048 				" not work properly.\n");
3049 
3050 			caller_fsuid = from_vfsuid(req->r_mnt_idmap, &init_user_ns,
3051 						   VFSUIDT_INIT(req->r_cred->fsuid));
3052 			caller_fsgid = from_vfsgid(req->r_mnt_idmap, &init_user_ns,
3053 						   VFSGIDT_INIT(req->r_cred->fsgid));
3054 		} else {
3055 			pr_err_ratelimited_client(cl,
3056 				"idmapped mount is used and CEPHFS_FEATURE_HAS_OWNER_UIDGID"
3057 				" is not supported by MDS. Fail request with -EIO.\n");
3058 
3059 			ret = -EIO;
3060 			goto out_err;
3061 		}
3062 	}
3063 
3064 	/*
3065 	 * The ceph_mds_request_head_legacy didn't contain a version field, and
3066 	 * one was added when we moved the message version from 3->4.
3067 	 */
3068 	if (legacy) {
3069 		msg->hdr.version = cpu_to_le16(3);
3070 		p = msg->front.iov_base + sizeof(*lhead);
3071 	} else if (request_head_version == 1) {
3072 		struct ceph_mds_request_head_old *ohead = msg->front.iov_base;
3073 
3074 		msg->hdr.version = cpu_to_le16(4);
3075 		ohead->version = cpu_to_le16(1);
3076 		p = msg->front.iov_base + sizeof(*ohead);
3077 	} else if (request_head_version == 2) {
3078 		struct ceph_mds_request_head *nhead = msg->front.iov_base;
3079 
3080 		msg->hdr.version = cpu_to_le16(6);
3081 		nhead->version = cpu_to_le16(2);
3082 
3083 		p = msg->front.iov_base + offsetofend(struct ceph_mds_request_head, ext_num_fwd);
3084 	} else {
3085 		struct ceph_mds_request_head *nhead = msg->front.iov_base;
3086 		kuid_t owner_fsuid;
3087 		kgid_t owner_fsgid;
3088 
3089 		msg->hdr.version = cpu_to_le16(6);
3090 		nhead->version = cpu_to_le16(CEPH_MDS_REQUEST_HEAD_VERSION);
3091 		nhead->struct_len = cpu_to_le32(sizeof(struct ceph_mds_request_head));
3092 
3093 		if (IS_CEPH_MDS_OP_NEWINODE(req->r_op)) {
3094 			owner_fsuid = from_vfsuid(req->r_mnt_idmap, &init_user_ns,
3095 						VFSUIDT_INIT(req->r_cred->fsuid));
3096 			owner_fsgid = from_vfsgid(req->r_mnt_idmap, &init_user_ns,
3097 						VFSGIDT_INIT(req->r_cred->fsgid));
3098 			nhead->owner_uid = cpu_to_le32(from_kuid(&init_user_ns, owner_fsuid));
3099 			nhead->owner_gid = cpu_to_le32(from_kgid(&init_user_ns, owner_fsgid));
3100 		} else {
3101 			nhead->owner_uid = cpu_to_le32(-1);
3102 			nhead->owner_gid = cpu_to_le32(-1);
3103 		}
3104 
3105 		p = msg->front.iov_base + sizeof(*nhead);
3106 	}
3107 
3108 	end = msg->front.iov_base + msg->front.iov_len;
3109 
3110 	lhead->mdsmap_epoch = cpu_to_le32(mdsc->mdsmap->m_epoch);
3111 	lhead->op = cpu_to_le32(req->r_op);
3112 	lhead->caller_uid = cpu_to_le32(from_kuid(&init_user_ns,
3113 						  caller_fsuid));
3114 	lhead->caller_gid = cpu_to_le32(from_kgid(&init_user_ns,
3115 						  caller_fsgid));
3116 	lhead->ino = cpu_to_le64(req->r_deleg_ino);
3117 	lhead->args = req->r_args;
3118 
3119 	ceph_encode_filepath(&p, end, ino1, path1);
3120 	ceph_encode_filepath(&p, end, ino2, path2);
3121 
3122 	/* make note of release offset, in case we need to replay */
3123 	req->r_request_release_offset = p - msg->front.iov_base;
3124 
3125 	/* cap releases */
3126 	releases = 0;
3127 	if (req->r_inode_drop)
3128 		releases += ceph_encode_inode_release(&p,
3129 		      req->r_inode ? req->r_inode : d_inode(req->r_dentry),
3130 		      mds, req->r_inode_drop, req->r_inode_unless,
3131 		      req->r_op == CEPH_MDS_OP_READDIR);
3132 	if (req->r_dentry_drop) {
3133 		ret = ceph_encode_dentry_release(&p, req->r_dentry,
3134 				req->r_parent, mds, req->r_dentry_drop,
3135 				req->r_dentry_unless);
3136 		if (ret < 0)
3137 			goto out_err;
3138 		releases += ret;
3139 	}
3140 	if (req->r_old_dentry_drop) {
3141 		ret = ceph_encode_dentry_release(&p, req->r_old_dentry,
3142 				req->r_old_dentry_dir, mds,
3143 				req->r_old_dentry_drop,
3144 				req->r_old_dentry_unless);
3145 		if (ret < 0)
3146 			goto out_err;
3147 		releases += ret;
3148 	}
3149 	if (req->r_old_inode_drop)
3150 		releases += ceph_encode_inode_release(&p,
3151 		      d_inode(req->r_old_dentry),
3152 		      mds, req->r_old_inode_drop, req->r_old_inode_unless, 0);
3153 
3154 	if (drop_cap_releases) {
3155 		releases = 0;
3156 		p = msg->front.iov_base + req->r_request_release_offset;
3157 	}
3158 
3159 	lhead->num_releases = cpu_to_le16(releases);
3160 
3161 	encode_mclientrequest_tail(&p, req);
3162 
3163 	if (WARN_ON_ONCE(p > end)) {
3164 		ceph_msg_put(msg);
3165 		msg = ERR_PTR(-ERANGE);
3166 		goto out_free2;
3167 	}
3168 
3169 	msg->front.iov_len = p - msg->front.iov_base;
3170 	msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
3171 
3172 	if (req->r_pagelist) {
3173 		struct ceph_pagelist *pagelist = req->r_pagelist;
3174 		ceph_msg_data_add_pagelist(msg, pagelist);
3175 		msg->hdr.data_len = cpu_to_le32(pagelist->length);
3176 	} else {
3177 		msg->hdr.data_len = 0;
3178 	}
3179 
3180 	msg->hdr.data_off = cpu_to_le16(0);
3181 
3182 out_free2:
3183 	if (freepath2)
3184 		ceph_mdsc_free_path((char *)path2, pathlen2);
3185 out_free1:
3186 	if (freepath1)
3187 		ceph_mdsc_free_path((char *)path1, pathlen1);
3188 out:
3189 	return msg;
3190 out_err:
3191 	ceph_msg_put(msg);
3192 	msg = ERR_PTR(ret);
3193 	goto out_free2;
3194 }
3195 
3196 /*
3197  * called under mdsc->mutex if error, under no mutex if
3198  * success.
3199  */
3200 static void complete_request(struct ceph_mds_client *mdsc,
3201 			     struct ceph_mds_request *req)
3202 {
3203 	req->r_end_latency = ktime_get();
3204 
3205 	if (req->r_callback)
3206 		req->r_callback(mdsc, req);
3207 	complete_all(&req->r_completion);
3208 }
3209 
3210 /*
3211  * called under mdsc->mutex
3212  */
3213 static int __prepare_send_request(struct ceph_mds_session *session,
3214 				  struct ceph_mds_request *req,
3215 				  bool drop_cap_releases)
3216 {
3217 	int mds = session->s_mds;
3218 	struct ceph_mds_client *mdsc = session->s_mdsc;
3219 	struct ceph_client *cl = mdsc->fsc->client;
3220 	struct ceph_mds_request_head_legacy *lhead;
3221 	struct ceph_mds_request_head *nhead;
3222 	struct ceph_msg *msg;
3223 	int flags = 0, old_max_retry;
3224 	bool old_version = !test_bit(CEPHFS_FEATURE_32BITS_RETRY_FWD,
3225 				     &session->s_features);
3226 
3227 	/*
3228 	 * Avoid inifinite retrying after overflow. The client will
3229 	 * increase the retry count and if the MDS is old version,
3230 	 * so we limit to retry at most 256 times.
3231 	 */
3232 	if (req->r_attempts) {
3233 	       old_max_retry = sizeof_field(struct ceph_mds_request_head_old,
3234 					    num_retry);
3235 	       old_max_retry = 1 << (old_max_retry * BITS_PER_BYTE);
3236 	       if ((old_version && req->r_attempts >= old_max_retry) ||
3237 		   ((uint32_t)req->r_attempts >= U32_MAX)) {
3238 			pr_warn_ratelimited_client(cl, "request tid %llu seq overflow\n",
3239 						   req->r_tid);
3240 			return -EMULTIHOP;
3241 	       }
3242 	}
3243 
3244 	req->r_attempts++;
3245 	if (req->r_inode) {
3246 		struct ceph_cap *cap =
3247 			ceph_get_cap_for_mds(ceph_inode(req->r_inode), mds);
3248 
3249 		if (cap)
3250 			req->r_sent_on_mseq = cap->mseq;
3251 		else
3252 			req->r_sent_on_mseq = -1;
3253 	}
3254 	doutc(cl, "%p tid %lld %s (attempt %d)\n", req, req->r_tid,
3255 	      ceph_mds_op_name(req->r_op), req->r_attempts);
3256 
3257 	if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
3258 		void *p;
3259 
3260 		/*
3261 		 * Replay.  Do not regenerate message (and rebuild
3262 		 * paths, etc.); just use the original message.
3263 		 * Rebuilding paths will break for renames because
3264 		 * d_move mangles the src name.
3265 		 */
3266 		msg = req->r_request;
3267 		lhead = find_legacy_request_head(msg->front.iov_base,
3268 						 session->s_con.peer_features);
3269 
3270 		flags = le32_to_cpu(lhead->flags);
3271 		flags |= CEPH_MDS_FLAG_REPLAY;
3272 		lhead->flags = cpu_to_le32(flags);
3273 
3274 		if (req->r_target_inode)
3275 			lhead->ino = cpu_to_le64(ceph_ino(req->r_target_inode));
3276 
3277 		lhead->num_retry = req->r_attempts - 1;
3278 		if (!old_version) {
3279 			nhead = (struct ceph_mds_request_head*)msg->front.iov_base;
3280 			nhead->ext_num_retry = cpu_to_le32(req->r_attempts - 1);
3281 		}
3282 
3283 		/* remove cap/dentry releases from message */
3284 		lhead->num_releases = 0;
3285 
3286 		p = msg->front.iov_base + req->r_request_release_offset;
3287 		encode_mclientrequest_tail(&p, req);
3288 
3289 		msg->front.iov_len = p - msg->front.iov_base;
3290 		msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
3291 		return 0;
3292 	}
3293 
3294 	if (req->r_request) {
3295 		ceph_msg_put(req->r_request);
3296 		req->r_request = NULL;
3297 	}
3298 	msg = create_request_message(session, req, drop_cap_releases);
3299 	if (IS_ERR(msg)) {
3300 		req->r_err = PTR_ERR(msg);
3301 		return PTR_ERR(msg);
3302 	}
3303 	req->r_request = msg;
3304 
3305 	lhead = find_legacy_request_head(msg->front.iov_base,
3306 					 session->s_con.peer_features);
3307 	lhead->oldest_client_tid = cpu_to_le64(__get_oldest_tid(mdsc));
3308 	if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags))
3309 		flags |= CEPH_MDS_FLAG_REPLAY;
3310 	if (test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags))
3311 		flags |= CEPH_MDS_FLAG_ASYNC;
3312 	if (req->r_parent)
3313 		flags |= CEPH_MDS_FLAG_WANT_DENTRY;
3314 	lhead->flags = cpu_to_le32(flags);
3315 	lhead->num_fwd = req->r_num_fwd;
3316 	lhead->num_retry = req->r_attempts - 1;
3317 	if (!old_version) {
3318 		nhead = (struct ceph_mds_request_head*)msg->front.iov_base;
3319 		nhead->ext_num_fwd = cpu_to_le32(req->r_num_fwd);
3320 		nhead->ext_num_retry = cpu_to_le32(req->r_attempts - 1);
3321 	}
3322 
3323 	doutc(cl, " r_parent = %p\n", req->r_parent);
3324 	return 0;
3325 }
3326 
3327 /*
3328  * called under mdsc->mutex
3329  */
3330 static int __send_request(struct ceph_mds_session *session,
3331 			  struct ceph_mds_request *req,
3332 			  bool drop_cap_releases)
3333 {
3334 	int err;
3335 
3336 	err = __prepare_send_request(session, req, drop_cap_releases);
3337 	if (!err) {
3338 		ceph_msg_get(req->r_request);
3339 		ceph_con_send(&session->s_con, req->r_request);
3340 	}
3341 
3342 	return err;
3343 }
3344 
3345 /*
3346  * send request, or put it on the appropriate wait list.
3347  */
3348 static void __do_request(struct ceph_mds_client *mdsc,
3349 			struct ceph_mds_request *req)
3350 {
3351 	struct ceph_client *cl = mdsc->fsc->client;
3352 	struct ceph_mds_session *session = NULL;
3353 	int mds = -1;
3354 	int err = 0;
3355 	bool random;
3356 
3357 	if (req->r_err || test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags)) {
3358 		if (test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags))
3359 			__unregister_request(mdsc, req);
3360 		return;
3361 	}
3362 
3363 	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_FENCE_IO) {
3364 		doutc(cl, "metadata corrupted\n");
3365 		err = -EIO;
3366 		goto finish;
3367 	}
3368 	if (req->r_timeout &&
3369 	    time_after_eq(jiffies, req->r_started + req->r_timeout)) {
3370 		doutc(cl, "timed out\n");
3371 		err = -ETIMEDOUT;
3372 		goto finish;
3373 	}
3374 	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_SHUTDOWN) {
3375 		doutc(cl, "forced umount\n");
3376 		err = -EIO;
3377 		goto finish;
3378 	}
3379 	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_MOUNTING) {
3380 		if (mdsc->mdsmap_err) {
3381 			err = mdsc->mdsmap_err;
3382 			doutc(cl, "mdsmap err %d\n", err);
3383 			goto finish;
3384 		}
3385 		if (mdsc->mdsmap->m_epoch == 0) {
3386 			doutc(cl, "no mdsmap, waiting for map\n");
3387 			list_add(&req->r_wait, &mdsc->waiting_for_map);
3388 			return;
3389 		}
3390 		if (!(mdsc->fsc->mount_options->flags &
3391 		      CEPH_MOUNT_OPT_MOUNTWAIT) &&
3392 		    !ceph_mdsmap_is_cluster_available(mdsc->mdsmap)) {
3393 			err = -EHOSTUNREACH;
3394 			goto finish;
3395 		}
3396 	}
3397 
3398 	put_request_session(req);
3399 
3400 	mds = __choose_mds(mdsc, req, &random);
3401 	if (mds < 0 ||
3402 	    ceph_mdsmap_get_state(mdsc->mdsmap, mds) < CEPH_MDS_STATE_ACTIVE) {
3403 		if (test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags)) {
3404 			err = -EJUKEBOX;
3405 			goto finish;
3406 		}
3407 		doutc(cl, "no mds or not active, waiting for map\n");
3408 		list_add(&req->r_wait, &mdsc->waiting_for_map);
3409 		return;
3410 	}
3411 
3412 	/* get, open session */
3413 	session = __ceph_lookup_mds_session(mdsc, mds);
3414 	if (!session) {
3415 		session = register_session(mdsc, mds);
3416 		if (IS_ERR(session)) {
3417 			err = PTR_ERR(session);
3418 			goto finish;
3419 		}
3420 	}
3421 	req->r_session = ceph_get_mds_session(session);
3422 
3423 	doutc(cl, "mds%d session %p state %s\n", mds, session,
3424 	      ceph_session_state_name(session->s_state));
3425 
3426 	/*
3427 	 * The old ceph will crash the MDSs when see unknown OPs
3428 	 */
3429 	if (req->r_feature_needed > 0 &&
3430 	    !test_bit(req->r_feature_needed, &session->s_features)) {
3431 		err = -EOPNOTSUPP;
3432 		goto out_session;
3433 	}
3434 
3435 	if (session->s_state != CEPH_MDS_SESSION_OPEN &&
3436 	    session->s_state != CEPH_MDS_SESSION_HUNG) {
3437 		/*
3438 		 * We cannot queue async requests since the caps and delegated
3439 		 * inodes are bound to the session. Just return -EJUKEBOX and
3440 		 * let the caller retry a sync request in that case.
3441 		 */
3442 		if (test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags)) {
3443 			err = -EJUKEBOX;
3444 			goto out_session;
3445 		}
3446 
3447 		/*
3448 		 * If the session has been REJECTED, then return a hard error,
3449 		 * unless it's a CLEANRECOVER mount, in which case we'll queue
3450 		 * it to the mdsc queue.
3451 		 */
3452 		if (session->s_state == CEPH_MDS_SESSION_REJECTED) {
3453 			if (ceph_test_mount_opt(mdsc->fsc, CLEANRECOVER))
3454 				list_add(&req->r_wait, &mdsc->waiting_for_map);
3455 			else
3456 				err = -EACCES;
3457 			goto out_session;
3458 		}
3459 
3460 		if (session->s_state == CEPH_MDS_SESSION_NEW ||
3461 		    session->s_state == CEPH_MDS_SESSION_CLOSING) {
3462 			err = __open_session(mdsc, session);
3463 			if (err)
3464 				goto out_session;
3465 			/* retry the same mds later */
3466 			if (random)
3467 				req->r_resend_mds = mds;
3468 		}
3469 		list_add(&req->r_wait, &session->s_waiting);
3470 		goto out_session;
3471 	}
3472 
3473 	/* send request */
3474 	req->r_resend_mds = -1;   /* forget any previous mds hint */
3475 
3476 	if (req->r_request_started == 0)   /* note request start time */
3477 		req->r_request_started = jiffies;
3478 
3479 	/*
3480 	 * For async create we will choose the auth MDS of frag in parent
3481 	 * directory to send the request and ususally this works fine, but
3482 	 * if the migrated the dirtory to another MDS before it could handle
3483 	 * it the request will be forwarded.
3484 	 *
3485 	 * And then the auth cap will be changed.
3486 	 */
3487 	if (test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags) && req->r_num_fwd) {
3488 		struct ceph_dentry_info *di = ceph_dentry(req->r_dentry);
3489 		struct ceph_inode_info *ci;
3490 		struct ceph_cap *cap;
3491 
3492 		/*
3493 		 * The request maybe handled very fast and the new inode
3494 		 * hasn't been linked to the dentry yet. We need to wait
3495 		 * for the ceph_finish_async_create(), which shouldn't be
3496 		 * stuck too long or fail in thoery, to finish when forwarding
3497 		 * the request.
3498 		 */
3499 		if (!d_inode(req->r_dentry)) {
3500 			err = wait_on_bit(&di->flags, CEPH_DENTRY_ASYNC_CREATE_BIT,
3501 					  TASK_KILLABLE);
3502 			if (err) {
3503 				mutex_lock(&req->r_fill_mutex);
3504 				set_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags);
3505 				mutex_unlock(&req->r_fill_mutex);
3506 				goto out_session;
3507 			}
3508 		}
3509 
3510 		ci = ceph_inode(d_inode(req->r_dentry));
3511 
3512 		spin_lock(&ci->i_ceph_lock);
3513 		cap = ci->i_auth_cap;
3514 		if (ci->i_ceph_flags & CEPH_I_ASYNC_CREATE && mds != cap->mds) {
3515 			doutc(cl, "session changed for auth cap %d -> %d\n",
3516 			      cap->session->s_mds, session->s_mds);
3517 
3518 			/* Remove the auth cap from old session */
3519 			spin_lock(&cap->session->s_cap_lock);
3520 			cap->session->s_nr_caps--;
3521 			list_del_init(&cap->session_caps);
3522 			spin_unlock(&cap->session->s_cap_lock);
3523 
3524 			/* Add the auth cap to the new session */
3525 			cap->mds = mds;
3526 			cap->session = session;
3527 			spin_lock(&session->s_cap_lock);
3528 			session->s_nr_caps++;
3529 			list_add_tail(&cap->session_caps, &session->s_caps);
3530 			spin_unlock(&session->s_cap_lock);
3531 
3532 			change_auth_cap_ses(ci, session);
3533 		}
3534 		spin_unlock(&ci->i_ceph_lock);
3535 	}
3536 
3537 	err = __send_request(session, req, false);
3538 
3539 out_session:
3540 	ceph_put_mds_session(session);
3541 finish:
3542 	if (err) {
3543 		doutc(cl, "early error %d\n", err);
3544 		req->r_err = err;
3545 		complete_request(mdsc, req);
3546 		__unregister_request(mdsc, req);
3547 	}
3548 	return;
3549 }
3550 
3551 /*
3552  * called under mdsc->mutex
3553  */
3554 static void __wake_requests(struct ceph_mds_client *mdsc,
3555 			    struct list_head *head)
3556 {
3557 	struct ceph_client *cl = mdsc->fsc->client;
3558 	struct ceph_mds_request *req;
3559 	LIST_HEAD(tmp_list);
3560 
3561 	list_splice_init(head, &tmp_list);
3562 
3563 	while (!list_empty(&tmp_list)) {
3564 		req = list_entry(tmp_list.next,
3565 				 struct ceph_mds_request, r_wait);
3566 		list_del_init(&req->r_wait);
3567 		doutc(cl, " wake request %p tid %llu\n", req,
3568 		      req->r_tid);
3569 		__do_request(mdsc, req);
3570 	}
3571 }
3572 
3573 /*
3574  * Wake up threads with requests pending for @mds, so that they can
3575  * resubmit their requests to a possibly different mds.
3576  */
3577 static void kick_requests(struct ceph_mds_client *mdsc, int mds)
3578 {
3579 	struct ceph_client *cl = mdsc->fsc->client;
3580 	struct ceph_mds_request *req;
3581 	struct rb_node *p = rb_first(&mdsc->request_tree);
3582 
3583 	doutc(cl, "kick_requests mds%d\n", mds);
3584 	while (p) {
3585 		req = rb_entry(p, struct ceph_mds_request, r_node);
3586 		p = rb_next(p);
3587 		if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags))
3588 			continue;
3589 		if (req->r_attempts > 0)
3590 			continue; /* only new requests */
3591 		if (req->r_session &&
3592 		    req->r_session->s_mds == mds) {
3593 			doutc(cl, " kicking tid %llu\n", req->r_tid);
3594 			list_del_init(&req->r_wait);
3595 			__do_request(mdsc, req);
3596 		}
3597 	}
3598 }
3599 
3600 int ceph_mdsc_submit_request(struct ceph_mds_client *mdsc, struct inode *dir,
3601 			      struct ceph_mds_request *req)
3602 {
3603 	struct ceph_client *cl = mdsc->fsc->client;
3604 	int err = 0;
3605 
3606 	/* take CAP_PIN refs for r_inode, r_parent, r_old_dentry */
3607 	if (req->r_inode)
3608 		ceph_get_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
3609 	if (req->r_parent) {
3610 		struct ceph_inode_info *ci = ceph_inode(req->r_parent);
3611 		int fmode = (req->r_op & CEPH_MDS_OP_WRITE) ?
3612 			    CEPH_FILE_MODE_WR : CEPH_FILE_MODE_RD;
3613 		spin_lock(&ci->i_ceph_lock);
3614 		ceph_take_cap_refs(ci, CEPH_CAP_PIN, false);
3615 		__ceph_touch_fmode(ci, mdsc, fmode);
3616 		spin_unlock(&ci->i_ceph_lock);
3617 	}
3618 	if (req->r_old_dentry_dir)
3619 		ceph_get_cap_refs(ceph_inode(req->r_old_dentry_dir),
3620 				  CEPH_CAP_PIN);
3621 
3622 	if (req->r_inode) {
3623 		err = ceph_wait_on_async_create(req->r_inode);
3624 		if (err) {
3625 			doutc(cl, "wait for async create returned: %d\n", err);
3626 			return err;
3627 		}
3628 	}
3629 
3630 	if (!err && req->r_old_inode) {
3631 		err = ceph_wait_on_async_create(req->r_old_inode);
3632 		if (err) {
3633 			doutc(cl, "wait for async create returned: %d\n", err);
3634 			return err;
3635 		}
3636 	}
3637 
3638 	doutc(cl, "submit_request on %p for inode %p\n", req, dir);
3639 	mutex_lock(&mdsc->mutex);
3640 	__register_request(mdsc, req, dir);
3641 	__do_request(mdsc, req);
3642 	err = req->r_err;
3643 	mutex_unlock(&mdsc->mutex);
3644 	return err;
3645 }
3646 
3647 int ceph_mdsc_wait_request(struct ceph_mds_client *mdsc,
3648 			   struct ceph_mds_request *req,
3649 			   ceph_mds_request_wait_callback_t wait_func)
3650 {
3651 	struct ceph_client *cl = mdsc->fsc->client;
3652 	int err;
3653 
3654 	/* wait */
3655 	doutc(cl, "do_request waiting\n");
3656 	if (wait_func) {
3657 		err = wait_func(mdsc, req);
3658 	} else {
3659 		long timeleft = wait_for_completion_killable_timeout(
3660 					&req->r_completion,
3661 					ceph_timeout_jiffies(req->r_timeout));
3662 		if (timeleft > 0)
3663 			err = 0;
3664 		else if (!timeleft)
3665 			err = -ETIMEDOUT;  /* timed out */
3666 		else
3667 			err = timeleft;  /* killed */
3668 	}
3669 	doutc(cl, "do_request waited, got %d\n", err);
3670 	mutex_lock(&mdsc->mutex);
3671 
3672 	/* only abort if we didn't race with a real reply */
3673 	if (test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags)) {
3674 		err = le32_to_cpu(req->r_reply_info.head->result);
3675 	} else if (err < 0) {
3676 		doutc(cl, "aborted request %lld with %d\n", req->r_tid, err);
3677 
3678 		/*
3679 		 * ensure we aren't running concurrently with
3680 		 * ceph_fill_trace or ceph_readdir_prepopulate, which
3681 		 * rely on locks (dir mutex) held by our caller.
3682 		 */
3683 		mutex_lock(&req->r_fill_mutex);
3684 		req->r_err = err;
3685 		set_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags);
3686 		mutex_unlock(&req->r_fill_mutex);
3687 
3688 		if (req->r_parent &&
3689 		    (req->r_op & CEPH_MDS_OP_WRITE))
3690 			ceph_invalidate_dir_request(req);
3691 	} else {
3692 		err = req->r_err;
3693 	}
3694 
3695 	mutex_unlock(&mdsc->mutex);
3696 	return err;
3697 }
3698 
3699 /*
3700  * Synchrously perform an mds request.  Take care of all of the
3701  * session setup, forwarding, retry details.
3702  */
3703 int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
3704 			 struct inode *dir,
3705 			 struct ceph_mds_request *req)
3706 {
3707 	struct ceph_client *cl = mdsc->fsc->client;
3708 	int err;
3709 
3710 	doutc(cl, "do_request on %p\n", req);
3711 
3712 	/* issue */
3713 	err = ceph_mdsc_submit_request(mdsc, dir, req);
3714 	if (!err)
3715 		err = ceph_mdsc_wait_request(mdsc, req, NULL);
3716 	doutc(cl, "do_request %p done, result %d\n", req, err);
3717 	return err;
3718 }
3719 
3720 /*
3721  * Invalidate dir's completeness, dentry lease state on an aborted MDS
3722  * namespace request.
3723  */
3724 void ceph_invalidate_dir_request(struct ceph_mds_request *req)
3725 {
3726 	struct inode *dir = req->r_parent;
3727 	struct inode *old_dir = req->r_old_dentry_dir;
3728 	struct ceph_client *cl = req->r_mdsc->fsc->client;
3729 
3730 	doutc(cl, "invalidate_dir_request %p %p (complete, lease(s))\n",
3731 	      dir, old_dir);
3732 
3733 	ceph_dir_clear_complete(dir);
3734 	if (old_dir)
3735 		ceph_dir_clear_complete(old_dir);
3736 	if (req->r_dentry)
3737 		ceph_invalidate_dentry_lease(req->r_dentry);
3738 	if (req->r_old_dentry)
3739 		ceph_invalidate_dentry_lease(req->r_old_dentry);
3740 }
3741 
3742 /*
3743  * Handle mds reply.
3744  *
3745  * We take the session mutex and parse and process the reply immediately.
3746  * This preserves the logical ordering of replies, capabilities, etc., sent
3747  * by the MDS as they are applied to our local cache.
3748  */
3749 static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
3750 {
3751 	struct ceph_mds_client *mdsc = session->s_mdsc;
3752 	struct ceph_client *cl = mdsc->fsc->client;
3753 	struct ceph_mds_request *req;
3754 	struct ceph_mds_reply_head *head = msg->front.iov_base;
3755 	struct ceph_mds_reply_info_parsed *rinfo;  /* parsed reply info */
3756 	struct ceph_snap_realm *realm;
3757 	u64 tid;
3758 	int err, result;
3759 	int mds = session->s_mds;
3760 	bool close_sessions = false;
3761 
3762 	if (msg->front.iov_len < sizeof(*head)) {
3763 		pr_err_client(cl, "got corrupt (short) reply\n");
3764 		ceph_msg_dump(msg);
3765 		return;
3766 	}
3767 
3768 	/* get request, session */
3769 	tid = le64_to_cpu(msg->hdr.tid);
3770 	mutex_lock(&mdsc->mutex);
3771 	req = lookup_get_request(mdsc, tid);
3772 	if (!req) {
3773 		doutc(cl, "on unknown tid %llu\n", tid);
3774 		mutex_unlock(&mdsc->mutex);
3775 		return;
3776 	}
3777 	doutc(cl, "handle_reply %p\n", req);
3778 
3779 	/* correct session? */
3780 	if (req->r_session != session) {
3781 		pr_err_client(cl, "got %llu on session mds%d not mds%d\n",
3782 			      tid, session->s_mds,
3783 			      req->r_session ? req->r_session->s_mds : -1);
3784 		mutex_unlock(&mdsc->mutex);
3785 		goto out;
3786 	}
3787 
3788 	/* dup? */
3789 	if ((test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags) && !head->safe) ||
3790 	    (test_bit(CEPH_MDS_R_GOT_SAFE, &req->r_req_flags) && head->safe)) {
3791 		pr_warn_client(cl, "got a dup %s reply on %llu from mds%d\n",
3792 			       head->safe ? "safe" : "unsafe", tid, mds);
3793 		mutex_unlock(&mdsc->mutex);
3794 		goto out;
3795 	}
3796 	if (test_bit(CEPH_MDS_R_GOT_SAFE, &req->r_req_flags)) {
3797 		pr_warn_client(cl, "got unsafe after safe on %llu from mds%d\n",
3798 			       tid, mds);
3799 		mutex_unlock(&mdsc->mutex);
3800 		goto out;
3801 	}
3802 
3803 	result = le32_to_cpu(head->result);
3804 
3805 	if (head->safe) {
3806 		set_bit(CEPH_MDS_R_GOT_SAFE, &req->r_req_flags);
3807 		__unregister_request(mdsc, req);
3808 
3809 		/* last request during umount? */
3810 		if (mdsc->stopping && !__get_oldest_req(mdsc))
3811 			complete_all(&mdsc->safe_umount_waiters);
3812 
3813 		if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
3814 			/*
3815 			 * We already handled the unsafe response, now do the
3816 			 * cleanup.  No need to examine the response; the MDS
3817 			 * doesn't include any result info in the safe
3818 			 * response.  And even if it did, there is nothing
3819 			 * useful we could do with a revised return value.
3820 			 */
3821 			doutc(cl, "got safe reply %llu, mds%d\n", tid, mds);
3822 
3823 			mutex_unlock(&mdsc->mutex);
3824 			goto out;
3825 		}
3826 	} else {
3827 		set_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags);
3828 		list_add_tail(&req->r_unsafe_item, &req->r_session->s_unsafe);
3829 	}
3830 
3831 	doutc(cl, "tid %lld result %d\n", tid, result);
3832 	if (test_bit(CEPHFS_FEATURE_REPLY_ENCODING, &session->s_features))
3833 		err = parse_reply_info(session, msg, req, (u64)-1);
3834 	else
3835 		err = parse_reply_info(session, msg, req,
3836 				       session->s_con.peer_features);
3837 	mutex_unlock(&mdsc->mutex);
3838 
3839 	/* Must find target inode outside of mutexes to avoid deadlocks */
3840 	rinfo = &req->r_reply_info;
3841 	if ((err >= 0) && rinfo->head->is_target) {
3842 		struct inode *in = xchg(&req->r_new_inode, NULL);
3843 		struct ceph_vino tvino = {
3844 			.ino  = le64_to_cpu(rinfo->targeti.in->ino),
3845 			.snap = le64_to_cpu(rinfo->targeti.in->snapid)
3846 		};
3847 
3848 		/*
3849 		 * If we ended up opening an existing inode, discard
3850 		 * r_new_inode
3851 		 */
3852 		if (req->r_op == CEPH_MDS_OP_CREATE &&
3853 		    !req->r_reply_info.has_create_ino) {
3854 			/* This should never happen on an async create */
3855 			WARN_ON_ONCE(req->r_deleg_ino);
3856 			iput(in);
3857 			in = NULL;
3858 		}
3859 
3860 		in = ceph_get_inode(mdsc->fsc->sb, tvino, in);
3861 		if (IS_ERR(in)) {
3862 			err = PTR_ERR(in);
3863 			mutex_lock(&session->s_mutex);
3864 			goto out_err;
3865 		}
3866 		req->r_target_inode = in;
3867 	}
3868 
3869 	mutex_lock(&session->s_mutex);
3870 	if (err < 0) {
3871 		pr_err_client(cl, "got corrupt reply mds%d(tid:%lld)\n",
3872 			      mds, tid);
3873 		ceph_msg_dump(msg);
3874 		goto out_err;
3875 	}
3876 
3877 	/* snap trace */
3878 	realm = NULL;
3879 	if (rinfo->snapblob_len) {
3880 		down_write(&mdsc->snap_rwsem);
3881 		err = ceph_update_snap_trace(mdsc, rinfo->snapblob,
3882 				rinfo->snapblob + rinfo->snapblob_len,
3883 				le32_to_cpu(head->op) == CEPH_MDS_OP_RMSNAP,
3884 				&realm);
3885 		if (err) {
3886 			up_write(&mdsc->snap_rwsem);
3887 			close_sessions = true;
3888 			if (err == -EIO)
3889 				ceph_msg_dump(msg);
3890 			goto out_err;
3891 		}
3892 		downgrade_write(&mdsc->snap_rwsem);
3893 	} else {
3894 		down_read(&mdsc->snap_rwsem);
3895 	}
3896 
3897 	/* insert trace into our cache */
3898 	mutex_lock(&req->r_fill_mutex);
3899 	current->journal_info = req;
3900 	err = ceph_fill_trace(mdsc->fsc->sb, req);
3901 	if (err == 0) {
3902 		if (result == 0 && (req->r_op == CEPH_MDS_OP_READDIR ||
3903 				    req->r_op == CEPH_MDS_OP_LSSNAP))
3904 			err = ceph_readdir_prepopulate(req, req->r_session);
3905 	}
3906 	current->journal_info = NULL;
3907 	mutex_unlock(&req->r_fill_mutex);
3908 
3909 	up_read(&mdsc->snap_rwsem);
3910 	if (realm)
3911 		ceph_put_snap_realm(mdsc, realm);
3912 
3913 	if (err == 0) {
3914 		if (req->r_target_inode &&
3915 		    test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
3916 			struct ceph_inode_info *ci =
3917 				ceph_inode(req->r_target_inode);
3918 			spin_lock(&ci->i_unsafe_lock);
3919 			list_add_tail(&req->r_unsafe_target_item,
3920 				      &ci->i_unsafe_iops);
3921 			spin_unlock(&ci->i_unsafe_lock);
3922 		}
3923 
3924 		ceph_unreserve_caps(mdsc, &req->r_caps_reservation);
3925 	}
3926 out_err:
3927 	mutex_lock(&mdsc->mutex);
3928 	if (!test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags)) {
3929 		if (err) {
3930 			req->r_err = err;
3931 		} else {
3932 			req->r_reply =  ceph_msg_get(msg);
3933 			set_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags);
3934 		}
3935 	} else {
3936 		doutc(cl, "reply arrived after request %lld was aborted\n", tid);
3937 	}
3938 	mutex_unlock(&mdsc->mutex);
3939 
3940 	mutex_unlock(&session->s_mutex);
3941 
3942 	/* kick calling process */
3943 	complete_request(mdsc, req);
3944 
3945 	ceph_update_metadata_metrics(&mdsc->metric, req->r_start_latency,
3946 				     req->r_end_latency, err);
3947 out:
3948 	ceph_mdsc_put_request(req);
3949 
3950 	/* Defer closing the sessions after s_mutex lock being released */
3951 	if (close_sessions)
3952 		ceph_mdsc_close_sessions(mdsc);
3953 	return;
3954 }
3955 
3956 
3957 
3958 /*
3959  * handle mds notification that our request has been forwarded.
3960  */
3961 static void handle_forward(struct ceph_mds_client *mdsc,
3962 			   struct ceph_mds_session *session,
3963 			   struct ceph_msg *msg)
3964 {
3965 	struct ceph_client *cl = mdsc->fsc->client;
3966 	struct ceph_mds_request *req;
3967 	u64 tid = le64_to_cpu(msg->hdr.tid);
3968 	u32 next_mds;
3969 	u32 fwd_seq;
3970 	int err = -EINVAL;
3971 	void *p = msg->front.iov_base;
3972 	void *end = p + msg->front.iov_len;
3973 	bool aborted = false;
3974 
3975 	ceph_decode_need(&p, end, 2*sizeof(u32), bad);
3976 	next_mds = ceph_decode_32(&p);
3977 	fwd_seq = ceph_decode_32(&p);
3978 
3979 	mutex_lock(&mdsc->mutex);
3980 	req = lookup_get_request(mdsc, tid);
3981 	if (!req) {
3982 		mutex_unlock(&mdsc->mutex);
3983 		doutc(cl, "forward tid %llu to mds%d - req dne\n", tid, next_mds);
3984 		return;  /* dup reply? */
3985 	}
3986 
3987 	if (test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags)) {
3988 		doutc(cl, "forward tid %llu aborted, unregistering\n", tid);
3989 		__unregister_request(mdsc, req);
3990 	} else if (fwd_seq <= req->r_num_fwd || (uint32_t)fwd_seq >= U32_MAX) {
3991 		/*
3992 		 * Avoid inifinite retrying after overflow.
3993 		 *
3994 		 * The MDS will increase the fwd count and in client side
3995 		 * if the num_fwd is less than the one saved in request
3996 		 * that means the MDS is an old version and overflowed of
3997 		 * 8 bits.
3998 		 */
3999 		mutex_lock(&req->r_fill_mutex);
4000 		req->r_err = -EMULTIHOP;
4001 		set_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags);
4002 		mutex_unlock(&req->r_fill_mutex);
4003 		aborted = true;
4004 		pr_warn_ratelimited_client(cl, "forward tid %llu seq overflow\n",
4005 					   tid);
4006 	} else {
4007 		/* resend. forward race not possible; mds would drop */
4008 		doutc(cl, "forward tid %llu to mds%d (we resend)\n", tid, next_mds);
4009 		BUG_ON(req->r_err);
4010 		BUG_ON(test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags));
4011 		req->r_attempts = 0;
4012 		req->r_num_fwd = fwd_seq;
4013 		req->r_resend_mds = next_mds;
4014 		put_request_session(req);
4015 		__do_request(mdsc, req);
4016 	}
4017 	mutex_unlock(&mdsc->mutex);
4018 
4019 	/* kick calling process */
4020 	if (aborted)
4021 		complete_request(mdsc, req);
4022 	ceph_mdsc_put_request(req);
4023 	return;
4024 
4025 bad:
4026 	pr_err_client(cl, "decode error err=%d\n", err);
4027 	ceph_msg_dump(msg);
4028 }
4029 
4030 static int __decode_session_metadata(void **p, void *end,
4031 				     bool *blocklisted)
4032 {
4033 	/* map<string,string> */
4034 	u32 n;
4035 	bool err_str;
4036 	ceph_decode_32_safe(p, end, n, bad);
4037 	while (n-- > 0) {
4038 		u32 len;
4039 		ceph_decode_32_safe(p, end, len, bad);
4040 		ceph_decode_need(p, end, len, bad);
4041 		err_str = !strncmp(*p, "error_string", len);
4042 		*p += len;
4043 		ceph_decode_32_safe(p, end, len, bad);
4044 		ceph_decode_need(p, end, len, bad);
4045 		/*
4046 		 * Match "blocklisted (blacklisted)" from newer MDSes,
4047 		 * or "blacklisted" from older MDSes.
4048 		 */
4049 		if (err_str && strnstr(*p, "blacklisted", len))
4050 			*blocklisted = true;
4051 		*p += len;
4052 	}
4053 	return 0;
4054 bad:
4055 	return -1;
4056 }
4057 
4058 /*
4059  * handle a mds session control message
4060  */
4061 static void handle_session(struct ceph_mds_session *session,
4062 			   struct ceph_msg *msg)
4063 {
4064 	struct ceph_mds_client *mdsc = session->s_mdsc;
4065 	struct ceph_client *cl = mdsc->fsc->client;
4066 	int mds = session->s_mds;
4067 	int msg_version = le16_to_cpu(msg->hdr.version);
4068 	void *p = msg->front.iov_base;
4069 	void *end = p + msg->front.iov_len;
4070 	struct ceph_mds_session_head *h;
4071 	u32 op;
4072 	u64 seq, features = 0;
4073 	int wake = 0;
4074 	bool blocklisted = false;
4075 
4076 	/* decode */
4077 	ceph_decode_need(&p, end, sizeof(*h), bad);
4078 	h = p;
4079 	p += sizeof(*h);
4080 
4081 	op = le32_to_cpu(h->op);
4082 	seq = le64_to_cpu(h->seq);
4083 
4084 	if (msg_version >= 3) {
4085 		u32 len;
4086 		/* version >= 2 and < 5, decode metadata, skip otherwise
4087 		 * as it's handled via flags.
4088 		 */
4089 		if (msg_version >= 5)
4090 			ceph_decode_skip_map(&p, end, string, string, bad);
4091 		else if (__decode_session_metadata(&p, end, &blocklisted) < 0)
4092 			goto bad;
4093 
4094 		/* version >= 3, feature bits */
4095 		ceph_decode_32_safe(&p, end, len, bad);
4096 		if (len) {
4097 			ceph_decode_64_safe(&p, end, features, bad);
4098 			p += len - sizeof(features);
4099 		}
4100 	}
4101 
4102 	if (msg_version >= 5) {
4103 		u32 flags, len;
4104 
4105 		/* version >= 4 */
4106 		ceph_decode_skip_16(&p, end, bad); /* struct_v, struct_cv */
4107 		ceph_decode_32_safe(&p, end, len, bad); /* len */
4108 		ceph_decode_skip_n(&p, end, len, bad); /* metric_spec */
4109 
4110 		/* version >= 5, flags   */
4111 		ceph_decode_32_safe(&p, end, flags, bad);
4112 		if (flags & CEPH_SESSION_BLOCKLISTED) {
4113 			pr_warn_client(cl, "mds%d session blocklisted\n",
4114 				       session->s_mds);
4115 			blocklisted = true;
4116 		}
4117 	}
4118 
4119 	mutex_lock(&mdsc->mutex);
4120 	if (op == CEPH_SESSION_CLOSE) {
4121 		ceph_get_mds_session(session);
4122 		__unregister_session(mdsc, session);
4123 	}
4124 	/* FIXME: this ttl calculation is generous */
4125 	session->s_ttl = jiffies + HZ*mdsc->mdsmap->m_session_autoclose;
4126 	mutex_unlock(&mdsc->mutex);
4127 
4128 	mutex_lock(&session->s_mutex);
4129 
4130 	doutc(cl, "mds%d %s %p state %s seq %llu\n", mds,
4131 	      ceph_session_op_name(op), session,
4132 	      ceph_session_state_name(session->s_state), seq);
4133 
4134 	if (session->s_state == CEPH_MDS_SESSION_HUNG) {
4135 		session->s_state = CEPH_MDS_SESSION_OPEN;
4136 		pr_info_client(cl, "mds%d came back\n", session->s_mds);
4137 	}
4138 
4139 	switch (op) {
4140 	case CEPH_SESSION_OPEN:
4141 		if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
4142 			pr_info_client(cl, "mds%d reconnect success\n",
4143 				       session->s_mds);
4144 
4145 		session->s_features = features;
4146 		if (session->s_state == CEPH_MDS_SESSION_OPEN) {
4147 			pr_notice_client(cl, "mds%d is already opened\n",
4148 					 session->s_mds);
4149 		} else {
4150 			session->s_state = CEPH_MDS_SESSION_OPEN;
4151 			renewed_caps(mdsc, session, 0);
4152 			if (test_bit(CEPHFS_FEATURE_METRIC_COLLECT,
4153 				     &session->s_features))
4154 				metric_schedule_delayed(&mdsc->metric);
4155 		}
4156 
4157 		/*
4158 		 * The connection maybe broken and the session in client
4159 		 * side has been reinitialized, need to update the seq
4160 		 * anyway.
4161 		 */
4162 		if (!session->s_seq && seq)
4163 			session->s_seq = seq;
4164 
4165 		wake = 1;
4166 		if (mdsc->stopping)
4167 			__close_session(mdsc, session);
4168 		break;
4169 
4170 	case CEPH_SESSION_RENEWCAPS:
4171 		if (session->s_renew_seq == seq)
4172 			renewed_caps(mdsc, session, 1);
4173 		break;
4174 
4175 	case CEPH_SESSION_CLOSE:
4176 		if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
4177 			pr_info_client(cl, "mds%d reconnect denied\n",
4178 				       session->s_mds);
4179 		session->s_state = CEPH_MDS_SESSION_CLOSED;
4180 		cleanup_session_requests(mdsc, session);
4181 		remove_session_caps(session);
4182 		wake = 2; /* for good measure */
4183 		wake_up_all(&mdsc->session_close_wq);
4184 		break;
4185 
4186 	case CEPH_SESSION_STALE:
4187 		pr_info_client(cl, "mds%d caps went stale, renewing\n",
4188 			       session->s_mds);
4189 		atomic_inc(&session->s_cap_gen);
4190 		session->s_cap_ttl = jiffies - 1;
4191 		send_renew_caps(mdsc, session);
4192 		break;
4193 
4194 	case CEPH_SESSION_RECALL_STATE:
4195 		ceph_trim_caps(mdsc, session, le32_to_cpu(h->max_caps));
4196 		break;
4197 
4198 	case CEPH_SESSION_FLUSHMSG:
4199 		/* flush cap releases */
4200 		spin_lock(&session->s_cap_lock);
4201 		if (session->s_num_cap_releases)
4202 			ceph_flush_cap_releases(mdsc, session);
4203 		spin_unlock(&session->s_cap_lock);
4204 
4205 		send_flushmsg_ack(mdsc, session, seq);
4206 		break;
4207 
4208 	case CEPH_SESSION_FORCE_RO:
4209 		doutc(cl, "force_session_readonly %p\n", session);
4210 		spin_lock(&session->s_cap_lock);
4211 		session->s_readonly = true;
4212 		spin_unlock(&session->s_cap_lock);
4213 		wake_up_session_caps(session, FORCE_RO);
4214 		break;
4215 
4216 	case CEPH_SESSION_REJECT:
4217 		WARN_ON(session->s_state != CEPH_MDS_SESSION_OPENING);
4218 		pr_info_client(cl, "mds%d rejected session\n",
4219 			       session->s_mds);
4220 		session->s_state = CEPH_MDS_SESSION_REJECTED;
4221 		cleanup_session_requests(mdsc, session);
4222 		remove_session_caps(session);
4223 		if (blocklisted)
4224 			mdsc->fsc->blocklisted = true;
4225 		wake = 2; /* for good measure */
4226 		break;
4227 
4228 	default:
4229 		pr_err_client(cl, "bad op %d mds%d\n", op, mds);
4230 		WARN_ON(1);
4231 	}
4232 
4233 	mutex_unlock(&session->s_mutex);
4234 	if (wake) {
4235 		mutex_lock(&mdsc->mutex);
4236 		__wake_requests(mdsc, &session->s_waiting);
4237 		if (wake == 2)
4238 			kick_requests(mdsc, mds);
4239 		mutex_unlock(&mdsc->mutex);
4240 	}
4241 	if (op == CEPH_SESSION_CLOSE)
4242 		ceph_put_mds_session(session);
4243 	return;
4244 
4245 bad:
4246 	pr_err_client(cl, "corrupt message mds%d len %d\n", mds,
4247 		      (int)msg->front.iov_len);
4248 	ceph_msg_dump(msg);
4249 	return;
4250 }
4251 
4252 void ceph_mdsc_release_dir_caps(struct ceph_mds_request *req)
4253 {
4254 	struct ceph_client *cl = req->r_mdsc->fsc->client;
4255 	int dcaps;
4256 
4257 	dcaps = xchg(&req->r_dir_caps, 0);
4258 	if (dcaps) {
4259 		doutc(cl, "releasing r_dir_caps=%s\n", ceph_cap_string(dcaps));
4260 		ceph_put_cap_refs(ceph_inode(req->r_parent), dcaps);
4261 	}
4262 }
4263 
4264 void ceph_mdsc_release_dir_caps_no_check(struct ceph_mds_request *req)
4265 {
4266 	struct ceph_client *cl = req->r_mdsc->fsc->client;
4267 	int dcaps;
4268 
4269 	dcaps = xchg(&req->r_dir_caps, 0);
4270 	if (dcaps) {
4271 		doutc(cl, "releasing r_dir_caps=%s\n", ceph_cap_string(dcaps));
4272 		ceph_put_cap_refs_no_check_caps(ceph_inode(req->r_parent),
4273 						dcaps);
4274 	}
4275 }
4276 
4277 /*
4278  * called under session->mutex.
4279  */
4280 static void replay_unsafe_requests(struct ceph_mds_client *mdsc,
4281 				   struct ceph_mds_session *session)
4282 {
4283 	struct ceph_mds_request *req, *nreq;
4284 	struct rb_node *p;
4285 
4286 	doutc(mdsc->fsc->client, "mds%d\n", session->s_mds);
4287 
4288 	mutex_lock(&mdsc->mutex);
4289 	list_for_each_entry_safe(req, nreq, &session->s_unsafe, r_unsafe_item)
4290 		__send_request(session, req, true);
4291 
4292 	/*
4293 	 * also re-send old requests when MDS enters reconnect stage. So that MDS
4294 	 * can process completed request in clientreplay stage.
4295 	 */
4296 	p = rb_first(&mdsc->request_tree);
4297 	while (p) {
4298 		req = rb_entry(p, struct ceph_mds_request, r_node);
4299 		p = rb_next(p);
4300 		if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags))
4301 			continue;
4302 		if (req->r_attempts == 0)
4303 			continue; /* only old requests */
4304 		if (!req->r_session)
4305 			continue;
4306 		if (req->r_session->s_mds != session->s_mds)
4307 			continue;
4308 
4309 		ceph_mdsc_release_dir_caps_no_check(req);
4310 
4311 		__send_request(session, req, true);
4312 	}
4313 	mutex_unlock(&mdsc->mutex);
4314 }
4315 
4316 static int send_reconnect_partial(struct ceph_reconnect_state *recon_state)
4317 {
4318 	struct ceph_msg *reply;
4319 	struct ceph_pagelist *_pagelist;
4320 	struct page *page;
4321 	__le32 *addr;
4322 	int err = -ENOMEM;
4323 
4324 	if (!recon_state->allow_multi)
4325 		return -ENOSPC;
4326 
4327 	/* can't handle message that contains both caps and realm */
4328 	BUG_ON(!recon_state->nr_caps == !recon_state->nr_realms);
4329 
4330 	/* pre-allocate new pagelist */
4331 	_pagelist = ceph_pagelist_alloc(GFP_NOFS);
4332 	if (!_pagelist)
4333 		return -ENOMEM;
4334 
4335 	reply = ceph_msg_new2(CEPH_MSG_CLIENT_RECONNECT, 0, 1, GFP_NOFS, false);
4336 	if (!reply)
4337 		goto fail_msg;
4338 
4339 	/* placeholder for nr_caps */
4340 	err = ceph_pagelist_encode_32(_pagelist, 0);
4341 	if (err < 0)
4342 		goto fail;
4343 
4344 	if (recon_state->nr_caps) {
4345 		/* currently encoding caps */
4346 		err = ceph_pagelist_encode_32(recon_state->pagelist, 0);
4347 		if (err)
4348 			goto fail;
4349 	} else {
4350 		/* placeholder for nr_realms (currently encoding relams) */
4351 		err = ceph_pagelist_encode_32(_pagelist, 0);
4352 		if (err < 0)
4353 			goto fail;
4354 	}
4355 
4356 	err = ceph_pagelist_encode_8(recon_state->pagelist, 1);
4357 	if (err)
4358 		goto fail;
4359 
4360 	page = list_first_entry(&recon_state->pagelist->head, struct page, lru);
4361 	addr = kmap_atomic(page);
4362 	if (recon_state->nr_caps) {
4363 		/* currently encoding caps */
4364 		*addr = cpu_to_le32(recon_state->nr_caps);
4365 	} else {
4366 		/* currently encoding relams */
4367 		*(addr + 1) = cpu_to_le32(recon_state->nr_realms);
4368 	}
4369 	kunmap_atomic(addr);
4370 
4371 	reply->hdr.version = cpu_to_le16(5);
4372 	reply->hdr.compat_version = cpu_to_le16(4);
4373 
4374 	reply->hdr.data_len = cpu_to_le32(recon_state->pagelist->length);
4375 	ceph_msg_data_add_pagelist(reply, recon_state->pagelist);
4376 
4377 	ceph_con_send(&recon_state->session->s_con, reply);
4378 	ceph_pagelist_release(recon_state->pagelist);
4379 
4380 	recon_state->pagelist = _pagelist;
4381 	recon_state->nr_caps = 0;
4382 	recon_state->nr_realms = 0;
4383 	recon_state->msg_version = 5;
4384 	return 0;
4385 fail:
4386 	ceph_msg_put(reply);
4387 fail_msg:
4388 	ceph_pagelist_release(_pagelist);
4389 	return err;
4390 }
4391 
4392 static struct dentry* d_find_primary(struct inode *inode)
4393 {
4394 	struct dentry *alias, *dn = NULL;
4395 
4396 	if (hlist_empty(&inode->i_dentry))
4397 		return NULL;
4398 
4399 	spin_lock(&inode->i_lock);
4400 	if (hlist_empty(&inode->i_dentry))
4401 		goto out_unlock;
4402 
4403 	if (S_ISDIR(inode->i_mode)) {
4404 		alias = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias);
4405 		if (!IS_ROOT(alias))
4406 			dn = dget(alias);
4407 		goto out_unlock;
4408 	}
4409 
4410 	hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
4411 		spin_lock(&alias->d_lock);
4412 		if (!d_unhashed(alias) &&
4413 		    (ceph_dentry(alias)->flags & CEPH_DENTRY_PRIMARY_LINK)) {
4414 			dn = dget_dlock(alias);
4415 		}
4416 		spin_unlock(&alias->d_lock);
4417 		if (dn)
4418 			break;
4419 	}
4420 out_unlock:
4421 	spin_unlock(&inode->i_lock);
4422 	return dn;
4423 }
4424 
4425 /*
4426  * Encode information about a cap for a reconnect with the MDS.
4427  */
4428 static int reconnect_caps_cb(struct inode *inode, int mds, void *arg)
4429 {
4430 	struct ceph_mds_client *mdsc = ceph_sb_to_mdsc(inode->i_sb);
4431 	struct ceph_client *cl = ceph_inode_to_client(inode);
4432 	union {
4433 		struct ceph_mds_cap_reconnect v2;
4434 		struct ceph_mds_cap_reconnect_v1 v1;
4435 	} rec;
4436 	struct ceph_inode_info *ci = ceph_inode(inode);
4437 	struct ceph_reconnect_state *recon_state = arg;
4438 	struct ceph_pagelist *pagelist = recon_state->pagelist;
4439 	struct dentry *dentry;
4440 	struct ceph_cap *cap;
4441 	char *path;
4442 	int pathlen = 0, err;
4443 	u64 pathbase;
4444 	u64 snap_follows;
4445 
4446 	dentry = d_find_primary(inode);
4447 	if (dentry) {
4448 		/* set pathbase to parent dir when msg_version >= 2 */
4449 		path = ceph_mdsc_build_path(mdsc, dentry, &pathlen, &pathbase,
4450 					    recon_state->msg_version >= 2);
4451 		dput(dentry);
4452 		if (IS_ERR(path)) {
4453 			err = PTR_ERR(path);
4454 			goto out_err;
4455 		}
4456 	} else {
4457 		path = NULL;
4458 		pathbase = 0;
4459 	}
4460 
4461 	spin_lock(&ci->i_ceph_lock);
4462 	cap = __get_cap_for_mds(ci, mds);
4463 	if (!cap) {
4464 		spin_unlock(&ci->i_ceph_lock);
4465 		err = 0;
4466 		goto out_err;
4467 	}
4468 	doutc(cl, " adding %p ino %llx.%llx cap %p %lld %s\n", inode,
4469 	      ceph_vinop(inode), cap, cap->cap_id,
4470 	      ceph_cap_string(cap->issued));
4471 
4472 	cap->seq = 0;        /* reset cap seq */
4473 	cap->issue_seq = 0;  /* and issue_seq */
4474 	cap->mseq = 0;       /* and migrate_seq */
4475 	cap->cap_gen = atomic_read(&cap->session->s_cap_gen);
4476 
4477 	/* These are lost when the session goes away */
4478 	if (S_ISDIR(inode->i_mode)) {
4479 		if (cap->issued & CEPH_CAP_DIR_CREATE) {
4480 			ceph_put_string(rcu_dereference_raw(ci->i_cached_layout.pool_ns));
4481 			memset(&ci->i_cached_layout, 0, sizeof(ci->i_cached_layout));
4482 		}
4483 		cap->issued &= ~CEPH_CAP_ANY_DIR_OPS;
4484 	}
4485 
4486 	if (recon_state->msg_version >= 2) {
4487 		rec.v2.cap_id = cpu_to_le64(cap->cap_id);
4488 		rec.v2.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
4489 		rec.v2.issued = cpu_to_le32(cap->issued);
4490 		rec.v2.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
4491 		rec.v2.pathbase = cpu_to_le64(pathbase);
4492 		rec.v2.flock_len = (__force __le32)
4493 			((ci->i_ceph_flags & CEPH_I_ERROR_FILELOCK) ? 0 : 1);
4494 	} else {
4495 		struct timespec64 ts;
4496 
4497 		rec.v1.cap_id = cpu_to_le64(cap->cap_id);
4498 		rec.v1.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
4499 		rec.v1.issued = cpu_to_le32(cap->issued);
4500 		rec.v1.size = cpu_to_le64(i_size_read(inode));
4501 		ts = inode_get_mtime(inode);
4502 		ceph_encode_timespec64(&rec.v1.mtime, &ts);
4503 		ts = inode_get_atime(inode);
4504 		ceph_encode_timespec64(&rec.v1.atime, &ts);
4505 		rec.v1.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
4506 		rec.v1.pathbase = cpu_to_le64(pathbase);
4507 	}
4508 
4509 	if (list_empty(&ci->i_cap_snaps)) {
4510 		snap_follows = ci->i_head_snapc ? ci->i_head_snapc->seq : 0;
4511 	} else {
4512 		struct ceph_cap_snap *capsnap =
4513 			list_first_entry(&ci->i_cap_snaps,
4514 					 struct ceph_cap_snap, ci_item);
4515 		snap_follows = capsnap->follows;
4516 	}
4517 	spin_unlock(&ci->i_ceph_lock);
4518 
4519 	if (recon_state->msg_version >= 2) {
4520 		int num_fcntl_locks, num_flock_locks;
4521 		struct ceph_filelock *flocks = NULL;
4522 		size_t struct_len, total_len = sizeof(u64);
4523 		u8 struct_v = 0;
4524 
4525 encode_again:
4526 		if (rec.v2.flock_len) {
4527 			ceph_count_locks(inode, &num_fcntl_locks, &num_flock_locks);
4528 		} else {
4529 			num_fcntl_locks = 0;
4530 			num_flock_locks = 0;
4531 		}
4532 		if (num_fcntl_locks + num_flock_locks > 0) {
4533 			flocks = kmalloc_array(num_fcntl_locks + num_flock_locks,
4534 					       sizeof(struct ceph_filelock),
4535 					       GFP_NOFS);
4536 			if (!flocks) {
4537 				err = -ENOMEM;
4538 				goto out_err;
4539 			}
4540 			err = ceph_encode_locks_to_buffer(inode, flocks,
4541 							  num_fcntl_locks,
4542 							  num_flock_locks);
4543 			if (err) {
4544 				kfree(flocks);
4545 				flocks = NULL;
4546 				if (err == -ENOSPC)
4547 					goto encode_again;
4548 				goto out_err;
4549 			}
4550 		} else {
4551 			kfree(flocks);
4552 			flocks = NULL;
4553 		}
4554 
4555 		if (recon_state->msg_version >= 3) {
4556 			/* version, compat_version and struct_len */
4557 			total_len += 2 * sizeof(u8) + sizeof(u32);
4558 			struct_v = 2;
4559 		}
4560 		/*
4561 		 * number of encoded locks is stable, so copy to pagelist
4562 		 */
4563 		struct_len = 2 * sizeof(u32) +
4564 			    (num_fcntl_locks + num_flock_locks) *
4565 			    sizeof(struct ceph_filelock);
4566 		rec.v2.flock_len = cpu_to_le32(struct_len);
4567 
4568 		struct_len += sizeof(u32) + pathlen + sizeof(rec.v2);
4569 
4570 		if (struct_v >= 2)
4571 			struct_len += sizeof(u64); /* snap_follows */
4572 
4573 		total_len += struct_len;
4574 
4575 		if (pagelist->length + total_len > RECONNECT_MAX_SIZE) {
4576 			err = send_reconnect_partial(recon_state);
4577 			if (err)
4578 				goto out_freeflocks;
4579 			pagelist = recon_state->pagelist;
4580 		}
4581 
4582 		err = ceph_pagelist_reserve(pagelist, total_len);
4583 		if (err)
4584 			goto out_freeflocks;
4585 
4586 		ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
4587 		if (recon_state->msg_version >= 3) {
4588 			ceph_pagelist_encode_8(pagelist, struct_v);
4589 			ceph_pagelist_encode_8(pagelist, 1);
4590 			ceph_pagelist_encode_32(pagelist, struct_len);
4591 		}
4592 		ceph_pagelist_encode_string(pagelist, path, pathlen);
4593 		ceph_pagelist_append(pagelist, &rec, sizeof(rec.v2));
4594 		ceph_locks_to_pagelist(flocks, pagelist,
4595 				       num_fcntl_locks, num_flock_locks);
4596 		if (struct_v >= 2)
4597 			ceph_pagelist_encode_64(pagelist, snap_follows);
4598 out_freeflocks:
4599 		kfree(flocks);
4600 	} else {
4601 		err = ceph_pagelist_reserve(pagelist,
4602 					    sizeof(u64) + sizeof(u32) +
4603 					    pathlen + sizeof(rec.v1));
4604 		if (err)
4605 			goto out_err;
4606 
4607 		ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
4608 		ceph_pagelist_encode_string(pagelist, path, pathlen);
4609 		ceph_pagelist_append(pagelist, &rec, sizeof(rec.v1));
4610 	}
4611 
4612 out_err:
4613 	ceph_mdsc_free_path(path, pathlen);
4614 	if (!err)
4615 		recon_state->nr_caps++;
4616 	return err;
4617 }
4618 
4619 static int encode_snap_realms(struct ceph_mds_client *mdsc,
4620 			      struct ceph_reconnect_state *recon_state)
4621 {
4622 	struct rb_node *p;
4623 	struct ceph_pagelist *pagelist = recon_state->pagelist;
4624 	struct ceph_client *cl = mdsc->fsc->client;
4625 	int err = 0;
4626 
4627 	if (recon_state->msg_version >= 4) {
4628 		err = ceph_pagelist_encode_32(pagelist, mdsc->num_snap_realms);
4629 		if (err < 0)
4630 			goto fail;
4631 	}
4632 
4633 	/*
4634 	 * snaprealms.  we provide mds with the ino, seq (version), and
4635 	 * parent for all of our realms.  If the mds has any newer info,
4636 	 * it will tell us.
4637 	 */
4638 	for (p = rb_first(&mdsc->snap_realms); p; p = rb_next(p)) {
4639 		struct ceph_snap_realm *realm =
4640 		       rb_entry(p, struct ceph_snap_realm, node);
4641 		struct ceph_mds_snaprealm_reconnect sr_rec;
4642 
4643 		if (recon_state->msg_version >= 4) {
4644 			size_t need = sizeof(u8) * 2 + sizeof(u32) +
4645 				      sizeof(sr_rec);
4646 
4647 			if (pagelist->length + need > RECONNECT_MAX_SIZE) {
4648 				err = send_reconnect_partial(recon_state);
4649 				if (err)
4650 					goto fail;
4651 				pagelist = recon_state->pagelist;
4652 			}
4653 
4654 			err = ceph_pagelist_reserve(pagelist, need);
4655 			if (err)
4656 				goto fail;
4657 
4658 			ceph_pagelist_encode_8(pagelist, 1);
4659 			ceph_pagelist_encode_8(pagelist, 1);
4660 			ceph_pagelist_encode_32(pagelist, sizeof(sr_rec));
4661 		}
4662 
4663 		doutc(cl, " adding snap realm %llx seq %lld parent %llx\n",
4664 		      realm->ino, realm->seq, realm->parent_ino);
4665 		sr_rec.ino = cpu_to_le64(realm->ino);
4666 		sr_rec.seq = cpu_to_le64(realm->seq);
4667 		sr_rec.parent = cpu_to_le64(realm->parent_ino);
4668 
4669 		err = ceph_pagelist_append(pagelist, &sr_rec, sizeof(sr_rec));
4670 		if (err)
4671 			goto fail;
4672 
4673 		recon_state->nr_realms++;
4674 	}
4675 fail:
4676 	return err;
4677 }
4678 
4679 
4680 /*
4681  * If an MDS fails and recovers, clients need to reconnect in order to
4682  * reestablish shared state.  This includes all caps issued through
4683  * this session _and_ the snap_realm hierarchy.  Because it's not
4684  * clear which snap realms the mds cares about, we send everything we
4685  * know about.. that ensures we'll then get any new info the
4686  * recovering MDS might have.
4687  *
4688  * This is a relatively heavyweight operation, but it's rare.
4689  */
4690 static void send_mds_reconnect(struct ceph_mds_client *mdsc,
4691 			       struct ceph_mds_session *session)
4692 {
4693 	struct ceph_client *cl = mdsc->fsc->client;
4694 	struct ceph_msg *reply;
4695 	int mds = session->s_mds;
4696 	int err = -ENOMEM;
4697 	struct ceph_reconnect_state recon_state = {
4698 		.session = session,
4699 	};
4700 	LIST_HEAD(dispose);
4701 
4702 	pr_info_client(cl, "mds%d reconnect start\n", mds);
4703 
4704 	recon_state.pagelist = ceph_pagelist_alloc(GFP_NOFS);
4705 	if (!recon_state.pagelist)
4706 		goto fail_nopagelist;
4707 
4708 	reply = ceph_msg_new2(CEPH_MSG_CLIENT_RECONNECT, 0, 1, GFP_NOFS, false);
4709 	if (!reply)
4710 		goto fail_nomsg;
4711 
4712 	xa_destroy(&session->s_delegated_inos);
4713 
4714 	mutex_lock(&session->s_mutex);
4715 	session->s_state = CEPH_MDS_SESSION_RECONNECTING;
4716 	session->s_seq = 0;
4717 
4718 	doutc(cl, "session %p state %s\n", session,
4719 	      ceph_session_state_name(session->s_state));
4720 
4721 	atomic_inc(&session->s_cap_gen);
4722 
4723 	spin_lock(&session->s_cap_lock);
4724 	/* don't know if session is readonly */
4725 	session->s_readonly = 0;
4726 	/*
4727 	 * notify __ceph_remove_cap() that we are composing cap reconnect.
4728 	 * If a cap get released before being added to the cap reconnect,
4729 	 * __ceph_remove_cap() should skip queuing cap release.
4730 	 */
4731 	session->s_cap_reconnect = 1;
4732 	/* drop old cap expires; we're about to reestablish that state */
4733 	detach_cap_releases(session, &dispose);
4734 	spin_unlock(&session->s_cap_lock);
4735 	dispose_cap_releases(mdsc, &dispose);
4736 
4737 	/* trim unused caps to reduce MDS's cache rejoin time */
4738 	if (mdsc->fsc->sb->s_root)
4739 		shrink_dcache_parent(mdsc->fsc->sb->s_root);
4740 
4741 	ceph_con_close(&session->s_con);
4742 	ceph_con_open(&session->s_con,
4743 		      CEPH_ENTITY_TYPE_MDS, mds,
4744 		      ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
4745 
4746 	/* replay unsafe requests */
4747 	replay_unsafe_requests(mdsc, session);
4748 
4749 	ceph_early_kick_flushing_caps(mdsc, session);
4750 
4751 	down_read(&mdsc->snap_rwsem);
4752 
4753 	/* placeholder for nr_caps */
4754 	err = ceph_pagelist_encode_32(recon_state.pagelist, 0);
4755 	if (err)
4756 		goto fail;
4757 
4758 	if (test_bit(CEPHFS_FEATURE_MULTI_RECONNECT, &session->s_features)) {
4759 		recon_state.msg_version = 3;
4760 		recon_state.allow_multi = true;
4761 	} else if (session->s_con.peer_features & CEPH_FEATURE_MDSENC) {
4762 		recon_state.msg_version = 3;
4763 	} else {
4764 		recon_state.msg_version = 2;
4765 	}
4766 	/* trsaverse this session's caps */
4767 	err = ceph_iterate_session_caps(session, reconnect_caps_cb, &recon_state);
4768 
4769 	spin_lock(&session->s_cap_lock);
4770 	session->s_cap_reconnect = 0;
4771 	spin_unlock(&session->s_cap_lock);
4772 
4773 	if (err < 0)
4774 		goto fail;
4775 
4776 	/* check if all realms can be encoded into current message */
4777 	if (mdsc->num_snap_realms) {
4778 		size_t total_len =
4779 			recon_state.pagelist->length +
4780 			mdsc->num_snap_realms *
4781 			sizeof(struct ceph_mds_snaprealm_reconnect);
4782 		if (recon_state.msg_version >= 4) {
4783 			/* number of realms */
4784 			total_len += sizeof(u32);
4785 			/* version, compat_version and struct_len */
4786 			total_len += mdsc->num_snap_realms *
4787 				     (2 * sizeof(u8) + sizeof(u32));
4788 		}
4789 		if (total_len > RECONNECT_MAX_SIZE) {
4790 			if (!recon_state.allow_multi) {
4791 				err = -ENOSPC;
4792 				goto fail;
4793 			}
4794 			if (recon_state.nr_caps) {
4795 				err = send_reconnect_partial(&recon_state);
4796 				if (err)
4797 					goto fail;
4798 			}
4799 			recon_state.msg_version = 5;
4800 		}
4801 	}
4802 
4803 	err = encode_snap_realms(mdsc, &recon_state);
4804 	if (err < 0)
4805 		goto fail;
4806 
4807 	if (recon_state.msg_version >= 5) {
4808 		err = ceph_pagelist_encode_8(recon_state.pagelist, 0);
4809 		if (err < 0)
4810 			goto fail;
4811 	}
4812 
4813 	if (recon_state.nr_caps || recon_state.nr_realms) {
4814 		struct page *page =
4815 			list_first_entry(&recon_state.pagelist->head,
4816 					struct page, lru);
4817 		__le32 *addr = kmap_atomic(page);
4818 		if (recon_state.nr_caps) {
4819 			WARN_ON(recon_state.nr_realms != mdsc->num_snap_realms);
4820 			*addr = cpu_to_le32(recon_state.nr_caps);
4821 		} else if (recon_state.msg_version >= 4) {
4822 			*(addr + 1) = cpu_to_le32(recon_state.nr_realms);
4823 		}
4824 		kunmap_atomic(addr);
4825 	}
4826 
4827 	reply->hdr.version = cpu_to_le16(recon_state.msg_version);
4828 	if (recon_state.msg_version >= 4)
4829 		reply->hdr.compat_version = cpu_to_le16(4);
4830 
4831 	reply->hdr.data_len = cpu_to_le32(recon_state.pagelist->length);
4832 	ceph_msg_data_add_pagelist(reply, recon_state.pagelist);
4833 
4834 	ceph_con_send(&session->s_con, reply);
4835 
4836 	mutex_unlock(&session->s_mutex);
4837 
4838 	mutex_lock(&mdsc->mutex);
4839 	__wake_requests(mdsc, &session->s_waiting);
4840 	mutex_unlock(&mdsc->mutex);
4841 
4842 	up_read(&mdsc->snap_rwsem);
4843 	ceph_pagelist_release(recon_state.pagelist);
4844 	return;
4845 
4846 fail:
4847 	ceph_msg_put(reply);
4848 	up_read(&mdsc->snap_rwsem);
4849 	mutex_unlock(&session->s_mutex);
4850 fail_nomsg:
4851 	ceph_pagelist_release(recon_state.pagelist);
4852 fail_nopagelist:
4853 	pr_err_client(cl, "error %d preparing reconnect for mds%d\n",
4854 		      err, mds);
4855 	return;
4856 }
4857 
4858 
4859 /*
4860  * compare old and new mdsmaps, kicking requests
4861  * and closing out old connections as necessary
4862  *
4863  * called under mdsc->mutex.
4864  */
4865 static void check_new_map(struct ceph_mds_client *mdsc,
4866 			  struct ceph_mdsmap *newmap,
4867 			  struct ceph_mdsmap *oldmap)
4868 {
4869 	int i, j, err;
4870 	int oldstate, newstate;
4871 	struct ceph_mds_session *s;
4872 	unsigned long targets[DIV_ROUND_UP(CEPH_MAX_MDS, sizeof(unsigned long))] = {0};
4873 	struct ceph_client *cl = mdsc->fsc->client;
4874 
4875 	doutc(cl, "new %u old %u\n", newmap->m_epoch, oldmap->m_epoch);
4876 
4877 	if (newmap->m_info) {
4878 		for (i = 0; i < newmap->possible_max_rank; i++) {
4879 			for (j = 0; j < newmap->m_info[i].num_export_targets; j++)
4880 				set_bit(newmap->m_info[i].export_targets[j], targets);
4881 		}
4882 	}
4883 
4884 	for (i = 0; i < oldmap->possible_max_rank && i < mdsc->max_sessions; i++) {
4885 		if (!mdsc->sessions[i])
4886 			continue;
4887 		s = mdsc->sessions[i];
4888 		oldstate = ceph_mdsmap_get_state(oldmap, i);
4889 		newstate = ceph_mdsmap_get_state(newmap, i);
4890 
4891 		doutc(cl, "mds%d state %s%s -> %s%s (session %s)\n",
4892 		      i, ceph_mds_state_name(oldstate),
4893 		      ceph_mdsmap_is_laggy(oldmap, i) ? " (laggy)" : "",
4894 		      ceph_mds_state_name(newstate),
4895 		      ceph_mdsmap_is_laggy(newmap, i) ? " (laggy)" : "",
4896 		      ceph_session_state_name(s->s_state));
4897 
4898 		if (i >= newmap->possible_max_rank) {
4899 			/* force close session for stopped mds */
4900 			ceph_get_mds_session(s);
4901 			__unregister_session(mdsc, s);
4902 			__wake_requests(mdsc, &s->s_waiting);
4903 			mutex_unlock(&mdsc->mutex);
4904 
4905 			mutex_lock(&s->s_mutex);
4906 			cleanup_session_requests(mdsc, s);
4907 			remove_session_caps(s);
4908 			mutex_unlock(&s->s_mutex);
4909 
4910 			ceph_put_mds_session(s);
4911 
4912 			mutex_lock(&mdsc->mutex);
4913 			kick_requests(mdsc, i);
4914 			continue;
4915 		}
4916 
4917 		if (memcmp(ceph_mdsmap_get_addr(oldmap, i),
4918 			   ceph_mdsmap_get_addr(newmap, i),
4919 			   sizeof(struct ceph_entity_addr))) {
4920 			/* just close it */
4921 			mutex_unlock(&mdsc->mutex);
4922 			mutex_lock(&s->s_mutex);
4923 			mutex_lock(&mdsc->mutex);
4924 			ceph_con_close(&s->s_con);
4925 			mutex_unlock(&s->s_mutex);
4926 			s->s_state = CEPH_MDS_SESSION_RESTARTING;
4927 		} else if (oldstate == newstate) {
4928 			continue;  /* nothing new with this mds */
4929 		}
4930 
4931 		/*
4932 		 * send reconnect?
4933 		 */
4934 		if (s->s_state == CEPH_MDS_SESSION_RESTARTING &&
4935 		    newstate >= CEPH_MDS_STATE_RECONNECT) {
4936 			mutex_unlock(&mdsc->mutex);
4937 			clear_bit(i, targets);
4938 			send_mds_reconnect(mdsc, s);
4939 			mutex_lock(&mdsc->mutex);
4940 		}
4941 
4942 		/*
4943 		 * kick request on any mds that has gone active.
4944 		 */
4945 		if (oldstate < CEPH_MDS_STATE_ACTIVE &&
4946 		    newstate >= CEPH_MDS_STATE_ACTIVE) {
4947 			if (oldstate != CEPH_MDS_STATE_CREATING &&
4948 			    oldstate != CEPH_MDS_STATE_STARTING)
4949 				pr_info_client(cl, "mds%d recovery completed\n",
4950 					       s->s_mds);
4951 			kick_requests(mdsc, i);
4952 			mutex_unlock(&mdsc->mutex);
4953 			mutex_lock(&s->s_mutex);
4954 			mutex_lock(&mdsc->mutex);
4955 			ceph_kick_flushing_caps(mdsc, s);
4956 			mutex_unlock(&s->s_mutex);
4957 			wake_up_session_caps(s, RECONNECT);
4958 		}
4959 	}
4960 
4961 	/*
4962 	 * Only open and reconnect sessions that don't exist yet.
4963 	 */
4964 	for (i = 0; i < newmap->possible_max_rank; i++) {
4965 		/*
4966 		 * In case the import MDS is crashed just after
4967 		 * the EImportStart journal is flushed, so when
4968 		 * a standby MDS takes over it and is replaying
4969 		 * the EImportStart journal the new MDS daemon
4970 		 * will wait the client to reconnect it, but the
4971 		 * client may never register/open the session yet.
4972 		 *
4973 		 * Will try to reconnect that MDS daemon if the
4974 		 * rank number is in the export targets array and
4975 		 * is the up:reconnect state.
4976 		 */
4977 		newstate = ceph_mdsmap_get_state(newmap, i);
4978 		if (!test_bit(i, targets) || newstate != CEPH_MDS_STATE_RECONNECT)
4979 			continue;
4980 
4981 		/*
4982 		 * The session maybe registered and opened by some
4983 		 * requests which were choosing random MDSes during
4984 		 * the mdsc->mutex's unlock/lock gap below in rare
4985 		 * case. But the related MDS daemon will just queue
4986 		 * that requests and be still waiting for the client's
4987 		 * reconnection request in up:reconnect state.
4988 		 */
4989 		s = __ceph_lookup_mds_session(mdsc, i);
4990 		if (likely(!s)) {
4991 			s = __open_export_target_session(mdsc, i);
4992 			if (IS_ERR(s)) {
4993 				err = PTR_ERR(s);
4994 				pr_err_client(cl,
4995 					      "failed to open export target session, err %d\n",
4996 					      err);
4997 				continue;
4998 			}
4999 		}
5000 		doutc(cl, "send reconnect to export target mds.%d\n", i);
5001 		mutex_unlock(&mdsc->mutex);
5002 		send_mds_reconnect(mdsc, s);
5003 		ceph_put_mds_session(s);
5004 		mutex_lock(&mdsc->mutex);
5005 	}
5006 
5007 	for (i = 0; i < newmap->possible_max_rank && i < mdsc->max_sessions; i++) {
5008 		s = mdsc->sessions[i];
5009 		if (!s)
5010 			continue;
5011 		if (!ceph_mdsmap_is_laggy(newmap, i))
5012 			continue;
5013 		if (s->s_state == CEPH_MDS_SESSION_OPEN ||
5014 		    s->s_state == CEPH_MDS_SESSION_HUNG ||
5015 		    s->s_state == CEPH_MDS_SESSION_CLOSING) {
5016 			doutc(cl, " connecting to export targets of laggy mds%d\n", i);
5017 			__open_export_target_sessions(mdsc, s);
5018 		}
5019 	}
5020 }
5021 
5022 
5023 
5024 /*
5025  * leases
5026  */
5027 
5028 /*
5029  * caller must hold session s_mutex, dentry->d_lock
5030  */
5031 void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry)
5032 {
5033 	struct ceph_dentry_info *di = ceph_dentry(dentry);
5034 
5035 	ceph_put_mds_session(di->lease_session);
5036 	di->lease_session = NULL;
5037 }
5038 
5039 static void handle_lease(struct ceph_mds_client *mdsc,
5040 			 struct ceph_mds_session *session,
5041 			 struct ceph_msg *msg)
5042 {
5043 	struct ceph_client *cl = mdsc->fsc->client;
5044 	struct super_block *sb = mdsc->fsc->sb;
5045 	struct inode *inode;
5046 	struct dentry *parent, *dentry;
5047 	struct ceph_dentry_info *di;
5048 	int mds = session->s_mds;
5049 	struct ceph_mds_lease *h = msg->front.iov_base;
5050 	u32 seq;
5051 	struct ceph_vino vino;
5052 	struct qstr dname;
5053 	int release = 0;
5054 
5055 	doutc(cl, "from mds%d\n", mds);
5056 
5057 	if (!ceph_inc_mds_stopping_blocker(mdsc, session))
5058 		return;
5059 
5060 	/* decode */
5061 	if (msg->front.iov_len < sizeof(*h) + sizeof(u32))
5062 		goto bad;
5063 	vino.ino = le64_to_cpu(h->ino);
5064 	vino.snap = CEPH_NOSNAP;
5065 	seq = le32_to_cpu(h->seq);
5066 	dname.len = get_unaligned_le32(h + 1);
5067 	if (msg->front.iov_len < sizeof(*h) + sizeof(u32) + dname.len)
5068 		goto bad;
5069 	dname.name = (void *)(h + 1) + sizeof(u32);
5070 
5071 	/* lookup inode */
5072 	inode = ceph_find_inode(sb, vino);
5073 	doutc(cl, "%s, ino %llx %p %.*s\n", ceph_lease_op_name(h->action),
5074 	      vino.ino, inode, dname.len, dname.name);
5075 
5076 	mutex_lock(&session->s_mutex);
5077 	if (!inode) {
5078 		doutc(cl, "no inode %llx\n", vino.ino);
5079 		goto release;
5080 	}
5081 
5082 	/* dentry */
5083 	parent = d_find_alias(inode);
5084 	if (!parent) {
5085 		doutc(cl, "no parent dentry on inode %p\n", inode);
5086 		WARN_ON(1);
5087 		goto release;  /* hrm... */
5088 	}
5089 	dname.hash = full_name_hash(parent, dname.name, dname.len);
5090 	dentry = d_lookup(parent, &dname);
5091 	dput(parent);
5092 	if (!dentry)
5093 		goto release;
5094 
5095 	spin_lock(&dentry->d_lock);
5096 	di = ceph_dentry(dentry);
5097 	switch (h->action) {
5098 	case CEPH_MDS_LEASE_REVOKE:
5099 		if (di->lease_session == session) {
5100 			if (ceph_seq_cmp(di->lease_seq, seq) > 0)
5101 				h->seq = cpu_to_le32(di->lease_seq);
5102 			__ceph_mdsc_drop_dentry_lease(dentry);
5103 		}
5104 		release = 1;
5105 		break;
5106 
5107 	case CEPH_MDS_LEASE_RENEW:
5108 		if (di->lease_session == session &&
5109 		    di->lease_gen == atomic_read(&session->s_cap_gen) &&
5110 		    di->lease_renew_from &&
5111 		    di->lease_renew_after == 0) {
5112 			unsigned long duration =
5113 				msecs_to_jiffies(le32_to_cpu(h->duration_ms));
5114 
5115 			di->lease_seq = seq;
5116 			di->time = di->lease_renew_from + duration;
5117 			di->lease_renew_after = di->lease_renew_from +
5118 				(duration >> 1);
5119 			di->lease_renew_from = 0;
5120 		}
5121 		break;
5122 	}
5123 	spin_unlock(&dentry->d_lock);
5124 	dput(dentry);
5125 
5126 	if (!release)
5127 		goto out;
5128 
5129 release:
5130 	/* let's just reuse the same message */
5131 	h->action = CEPH_MDS_LEASE_REVOKE_ACK;
5132 	ceph_msg_get(msg);
5133 	ceph_con_send(&session->s_con, msg);
5134 
5135 out:
5136 	mutex_unlock(&session->s_mutex);
5137 	iput(inode);
5138 
5139 	ceph_dec_mds_stopping_blocker(mdsc);
5140 	return;
5141 
5142 bad:
5143 	ceph_dec_mds_stopping_blocker(mdsc);
5144 
5145 	pr_err_client(cl, "corrupt lease message\n");
5146 	ceph_msg_dump(msg);
5147 }
5148 
5149 void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
5150 			      struct dentry *dentry, char action,
5151 			      u32 seq)
5152 {
5153 	struct ceph_client *cl = session->s_mdsc->fsc->client;
5154 	struct ceph_msg *msg;
5155 	struct ceph_mds_lease *lease;
5156 	struct inode *dir;
5157 	int len = sizeof(*lease) + sizeof(u32) + NAME_MAX;
5158 
5159 	doutc(cl, "identry %p %s to mds%d\n", dentry, ceph_lease_op_name(action),
5160 	      session->s_mds);
5161 
5162 	msg = ceph_msg_new(CEPH_MSG_CLIENT_LEASE, len, GFP_NOFS, false);
5163 	if (!msg)
5164 		return;
5165 	lease = msg->front.iov_base;
5166 	lease->action = action;
5167 	lease->seq = cpu_to_le32(seq);
5168 
5169 	spin_lock(&dentry->d_lock);
5170 	dir = d_inode(dentry->d_parent);
5171 	lease->ino = cpu_to_le64(ceph_ino(dir));
5172 	lease->first = lease->last = cpu_to_le64(ceph_snap(dir));
5173 
5174 	put_unaligned_le32(dentry->d_name.len, lease + 1);
5175 	memcpy((void *)(lease + 1) + 4,
5176 	       dentry->d_name.name, dentry->d_name.len);
5177 	spin_unlock(&dentry->d_lock);
5178 
5179 	ceph_con_send(&session->s_con, msg);
5180 }
5181 
5182 /*
5183  * lock unlock the session, to wait ongoing session activities
5184  */
5185 static void lock_unlock_session(struct ceph_mds_session *s)
5186 {
5187 	mutex_lock(&s->s_mutex);
5188 	mutex_unlock(&s->s_mutex);
5189 }
5190 
5191 static void maybe_recover_session(struct ceph_mds_client *mdsc)
5192 {
5193 	struct ceph_client *cl = mdsc->fsc->client;
5194 	struct ceph_fs_client *fsc = mdsc->fsc;
5195 
5196 	if (!ceph_test_mount_opt(fsc, CLEANRECOVER))
5197 		return;
5198 
5199 	if (READ_ONCE(fsc->mount_state) != CEPH_MOUNT_MOUNTED)
5200 		return;
5201 
5202 	if (!READ_ONCE(fsc->blocklisted))
5203 		return;
5204 
5205 	pr_info_client(cl, "auto reconnect after blocklisted\n");
5206 	ceph_force_reconnect(fsc->sb);
5207 }
5208 
5209 bool check_session_state(struct ceph_mds_session *s)
5210 {
5211 	struct ceph_client *cl = s->s_mdsc->fsc->client;
5212 
5213 	switch (s->s_state) {
5214 	case CEPH_MDS_SESSION_OPEN:
5215 		if (s->s_ttl && time_after(jiffies, s->s_ttl)) {
5216 			s->s_state = CEPH_MDS_SESSION_HUNG;
5217 			pr_info_client(cl, "mds%d hung\n", s->s_mds);
5218 		}
5219 		break;
5220 	case CEPH_MDS_SESSION_CLOSING:
5221 	case CEPH_MDS_SESSION_NEW:
5222 	case CEPH_MDS_SESSION_RESTARTING:
5223 	case CEPH_MDS_SESSION_CLOSED:
5224 	case CEPH_MDS_SESSION_REJECTED:
5225 		return false;
5226 	}
5227 
5228 	return true;
5229 }
5230 
5231 /*
5232  * If the sequence is incremented while we're waiting on a REQUEST_CLOSE reply,
5233  * then we need to retransmit that request.
5234  */
5235 void inc_session_sequence(struct ceph_mds_session *s)
5236 {
5237 	struct ceph_client *cl = s->s_mdsc->fsc->client;
5238 
5239 	lockdep_assert_held(&s->s_mutex);
5240 
5241 	s->s_seq++;
5242 
5243 	if (s->s_state == CEPH_MDS_SESSION_CLOSING) {
5244 		int ret;
5245 
5246 		doutc(cl, "resending session close request for mds%d\n", s->s_mds);
5247 		ret = request_close_session(s);
5248 		if (ret < 0)
5249 			pr_err_client(cl, "unable to close session to mds%d: %d\n",
5250 				      s->s_mds, ret);
5251 	}
5252 }
5253 
5254 /*
5255  * delayed work -- periodically trim expired leases, renew caps with mds.  If
5256  * the @delay parameter is set to 0 or if it's more than 5 secs, the default
5257  * workqueue delay value of 5 secs will be used.
5258  */
5259 static void schedule_delayed(struct ceph_mds_client *mdsc, unsigned long delay)
5260 {
5261 	unsigned long max_delay = HZ * 5;
5262 
5263 	/* 5 secs default delay */
5264 	if (!delay || (delay > max_delay))
5265 		delay = max_delay;
5266 	schedule_delayed_work(&mdsc->delayed_work,
5267 			      round_jiffies_relative(delay));
5268 }
5269 
5270 static void delayed_work(struct work_struct *work)
5271 {
5272 	struct ceph_mds_client *mdsc =
5273 		container_of(work, struct ceph_mds_client, delayed_work.work);
5274 	unsigned long delay;
5275 	int renew_interval;
5276 	int renew_caps;
5277 	int i;
5278 
5279 	doutc(mdsc->fsc->client, "mdsc delayed_work\n");
5280 
5281 	if (mdsc->stopping >= CEPH_MDSC_STOPPING_FLUSHED)
5282 		return;
5283 
5284 	mutex_lock(&mdsc->mutex);
5285 	renew_interval = mdsc->mdsmap->m_session_timeout >> 2;
5286 	renew_caps = time_after_eq(jiffies, HZ*renew_interval +
5287 				   mdsc->last_renew_caps);
5288 	if (renew_caps)
5289 		mdsc->last_renew_caps = jiffies;
5290 
5291 	for (i = 0; i < mdsc->max_sessions; i++) {
5292 		struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
5293 		if (!s)
5294 			continue;
5295 
5296 		if (!check_session_state(s)) {
5297 			ceph_put_mds_session(s);
5298 			continue;
5299 		}
5300 		mutex_unlock(&mdsc->mutex);
5301 
5302 		mutex_lock(&s->s_mutex);
5303 		if (renew_caps)
5304 			send_renew_caps(mdsc, s);
5305 		else
5306 			ceph_con_keepalive(&s->s_con);
5307 		if (s->s_state == CEPH_MDS_SESSION_OPEN ||
5308 		    s->s_state == CEPH_MDS_SESSION_HUNG)
5309 			ceph_send_cap_releases(mdsc, s);
5310 		mutex_unlock(&s->s_mutex);
5311 		ceph_put_mds_session(s);
5312 
5313 		mutex_lock(&mdsc->mutex);
5314 	}
5315 	mutex_unlock(&mdsc->mutex);
5316 
5317 	delay = ceph_check_delayed_caps(mdsc);
5318 
5319 	ceph_queue_cap_reclaim_work(mdsc);
5320 
5321 	ceph_trim_snapid_map(mdsc);
5322 
5323 	maybe_recover_session(mdsc);
5324 
5325 	schedule_delayed(mdsc, delay);
5326 }
5327 
5328 int ceph_mdsc_init(struct ceph_fs_client *fsc)
5329 
5330 {
5331 	struct ceph_mds_client *mdsc;
5332 	int err;
5333 
5334 	mdsc = kzalloc(sizeof(struct ceph_mds_client), GFP_NOFS);
5335 	if (!mdsc)
5336 		return -ENOMEM;
5337 	mdsc->fsc = fsc;
5338 	mutex_init(&mdsc->mutex);
5339 	mdsc->mdsmap = kzalloc(sizeof(*mdsc->mdsmap), GFP_NOFS);
5340 	if (!mdsc->mdsmap) {
5341 		err = -ENOMEM;
5342 		goto err_mdsc;
5343 	}
5344 
5345 	init_completion(&mdsc->safe_umount_waiters);
5346 	spin_lock_init(&mdsc->stopping_lock);
5347 	atomic_set(&mdsc->stopping_blockers, 0);
5348 	init_completion(&mdsc->stopping_waiter);
5349 	init_waitqueue_head(&mdsc->session_close_wq);
5350 	INIT_LIST_HEAD(&mdsc->waiting_for_map);
5351 	mdsc->quotarealms_inodes = RB_ROOT;
5352 	mutex_init(&mdsc->quotarealms_inodes_mutex);
5353 	init_rwsem(&mdsc->snap_rwsem);
5354 	mdsc->snap_realms = RB_ROOT;
5355 	INIT_LIST_HEAD(&mdsc->snap_empty);
5356 	spin_lock_init(&mdsc->snap_empty_lock);
5357 	mdsc->request_tree = RB_ROOT;
5358 	INIT_DELAYED_WORK(&mdsc->delayed_work, delayed_work);
5359 	mdsc->last_renew_caps = jiffies;
5360 	INIT_LIST_HEAD(&mdsc->cap_delay_list);
5361 	INIT_LIST_HEAD(&mdsc->cap_wait_list);
5362 	spin_lock_init(&mdsc->cap_delay_lock);
5363 	INIT_LIST_HEAD(&mdsc->snap_flush_list);
5364 	spin_lock_init(&mdsc->snap_flush_lock);
5365 	mdsc->last_cap_flush_tid = 1;
5366 	INIT_LIST_HEAD(&mdsc->cap_flush_list);
5367 	INIT_LIST_HEAD(&mdsc->cap_dirty_migrating);
5368 	spin_lock_init(&mdsc->cap_dirty_lock);
5369 	init_waitqueue_head(&mdsc->cap_flushing_wq);
5370 	INIT_WORK(&mdsc->cap_reclaim_work, ceph_cap_reclaim_work);
5371 	err = ceph_metric_init(&mdsc->metric);
5372 	if (err)
5373 		goto err_mdsmap;
5374 
5375 	spin_lock_init(&mdsc->dentry_list_lock);
5376 	INIT_LIST_HEAD(&mdsc->dentry_leases);
5377 	INIT_LIST_HEAD(&mdsc->dentry_dir_leases);
5378 
5379 	ceph_caps_init(mdsc);
5380 	ceph_adjust_caps_max_min(mdsc, fsc->mount_options);
5381 
5382 	spin_lock_init(&mdsc->snapid_map_lock);
5383 	mdsc->snapid_map_tree = RB_ROOT;
5384 	INIT_LIST_HEAD(&mdsc->snapid_map_lru);
5385 
5386 	init_rwsem(&mdsc->pool_perm_rwsem);
5387 	mdsc->pool_perm_tree = RB_ROOT;
5388 
5389 	strscpy(mdsc->nodename, utsname()->nodename,
5390 		sizeof(mdsc->nodename));
5391 
5392 	fsc->mdsc = mdsc;
5393 	return 0;
5394 
5395 err_mdsmap:
5396 	kfree(mdsc->mdsmap);
5397 err_mdsc:
5398 	kfree(mdsc);
5399 	return err;
5400 }
5401 
5402 /*
5403  * Wait for safe replies on open mds requests.  If we time out, drop
5404  * all requests from the tree to avoid dangling dentry refs.
5405  */
5406 static void wait_requests(struct ceph_mds_client *mdsc)
5407 {
5408 	struct ceph_client *cl = mdsc->fsc->client;
5409 	struct ceph_options *opts = mdsc->fsc->client->options;
5410 	struct ceph_mds_request *req;
5411 
5412 	mutex_lock(&mdsc->mutex);
5413 	if (__get_oldest_req(mdsc)) {
5414 		mutex_unlock(&mdsc->mutex);
5415 
5416 		doutc(cl, "waiting for requests\n");
5417 		wait_for_completion_timeout(&mdsc->safe_umount_waiters,
5418 				    ceph_timeout_jiffies(opts->mount_timeout));
5419 
5420 		/* tear down remaining requests */
5421 		mutex_lock(&mdsc->mutex);
5422 		while ((req = __get_oldest_req(mdsc))) {
5423 			doutc(cl, "timed out on tid %llu\n", req->r_tid);
5424 			list_del_init(&req->r_wait);
5425 			__unregister_request(mdsc, req);
5426 		}
5427 	}
5428 	mutex_unlock(&mdsc->mutex);
5429 	doutc(cl, "done\n");
5430 }
5431 
5432 void send_flush_mdlog(struct ceph_mds_session *s)
5433 {
5434 	struct ceph_client *cl = s->s_mdsc->fsc->client;
5435 	struct ceph_msg *msg;
5436 
5437 	/*
5438 	 * Pre-luminous MDS crashes when it sees an unknown session request
5439 	 */
5440 	if (!CEPH_HAVE_FEATURE(s->s_con.peer_features, SERVER_LUMINOUS))
5441 		return;
5442 
5443 	mutex_lock(&s->s_mutex);
5444 	doutc(cl, "request mdlog flush to mds%d (%s)s seq %lld\n",
5445 	      s->s_mds, ceph_session_state_name(s->s_state), s->s_seq);
5446 	msg = ceph_create_session_msg(CEPH_SESSION_REQUEST_FLUSH_MDLOG,
5447 				      s->s_seq);
5448 	if (!msg) {
5449 		pr_err_client(cl, "failed to request mdlog flush to mds%d (%s) seq %lld\n",
5450 			      s->s_mds, ceph_session_state_name(s->s_state), s->s_seq);
5451 	} else {
5452 		ceph_con_send(&s->s_con, msg);
5453 	}
5454 	mutex_unlock(&s->s_mutex);
5455 }
5456 
5457 /*
5458  * called before mount is ro, and before dentries are torn down.
5459  * (hmm, does this still race with new lookups?)
5460  */
5461 void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc)
5462 {
5463 	doutc(mdsc->fsc->client, "begin\n");
5464 	mdsc->stopping = CEPH_MDSC_STOPPING_BEGIN;
5465 
5466 	ceph_mdsc_iterate_sessions(mdsc, send_flush_mdlog, true);
5467 	ceph_mdsc_iterate_sessions(mdsc, lock_unlock_session, false);
5468 	ceph_flush_dirty_caps(mdsc);
5469 	wait_requests(mdsc);
5470 
5471 	/*
5472 	 * wait for reply handlers to drop their request refs and
5473 	 * their inode/dcache refs
5474 	 */
5475 	ceph_msgr_flush();
5476 
5477 	ceph_cleanup_quotarealms_inodes(mdsc);
5478 	doutc(mdsc->fsc->client, "done\n");
5479 }
5480 
5481 /*
5482  * flush the mdlog and wait for all write mds requests to flush.
5483  */
5484 static void flush_mdlog_and_wait_mdsc_unsafe_requests(struct ceph_mds_client *mdsc,
5485 						 u64 want_tid)
5486 {
5487 	struct ceph_client *cl = mdsc->fsc->client;
5488 	struct ceph_mds_request *req = NULL, *nextreq;
5489 	struct ceph_mds_session *last_session = NULL;
5490 	struct rb_node *n;
5491 
5492 	mutex_lock(&mdsc->mutex);
5493 	doutc(cl, "want %lld\n", want_tid);
5494 restart:
5495 	req = __get_oldest_req(mdsc);
5496 	while (req && req->r_tid <= want_tid) {
5497 		/* find next request */
5498 		n = rb_next(&req->r_node);
5499 		if (n)
5500 			nextreq = rb_entry(n, struct ceph_mds_request, r_node);
5501 		else
5502 			nextreq = NULL;
5503 		if (req->r_op != CEPH_MDS_OP_SETFILELOCK &&
5504 		    (req->r_op & CEPH_MDS_OP_WRITE)) {
5505 			struct ceph_mds_session *s = req->r_session;
5506 
5507 			if (!s) {
5508 				req = nextreq;
5509 				continue;
5510 			}
5511 
5512 			/* write op */
5513 			ceph_mdsc_get_request(req);
5514 			if (nextreq)
5515 				ceph_mdsc_get_request(nextreq);
5516 			s = ceph_get_mds_session(s);
5517 			mutex_unlock(&mdsc->mutex);
5518 
5519 			/* send flush mdlog request to MDS */
5520 			if (last_session != s) {
5521 				send_flush_mdlog(s);
5522 				ceph_put_mds_session(last_session);
5523 				last_session = s;
5524 			} else {
5525 				ceph_put_mds_session(s);
5526 			}
5527 			doutc(cl, "wait on %llu (want %llu)\n",
5528 			      req->r_tid, want_tid);
5529 			wait_for_completion(&req->r_safe_completion);
5530 
5531 			mutex_lock(&mdsc->mutex);
5532 			ceph_mdsc_put_request(req);
5533 			if (!nextreq)
5534 				break;  /* next dne before, so we're done! */
5535 			if (RB_EMPTY_NODE(&nextreq->r_node)) {
5536 				/* next request was removed from tree */
5537 				ceph_mdsc_put_request(nextreq);
5538 				goto restart;
5539 			}
5540 			ceph_mdsc_put_request(nextreq);  /* won't go away */
5541 		}
5542 		req = nextreq;
5543 	}
5544 	mutex_unlock(&mdsc->mutex);
5545 	ceph_put_mds_session(last_session);
5546 	doutc(cl, "done\n");
5547 }
5548 
5549 void ceph_mdsc_sync(struct ceph_mds_client *mdsc)
5550 {
5551 	struct ceph_client *cl = mdsc->fsc->client;
5552 	u64 want_tid, want_flush;
5553 
5554 	if (READ_ONCE(mdsc->fsc->mount_state) >= CEPH_MOUNT_SHUTDOWN)
5555 		return;
5556 
5557 	doutc(cl, "sync\n");
5558 	mutex_lock(&mdsc->mutex);
5559 	want_tid = mdsc->last_tid;
5560 	mutex_unlock(&mdsc->mutex);
5561 
5562 	ceph_flush_dirty_caps(mdsc);
5563 	spin_lock(&mdsc->cap_dirty_lock);
5564 	want_flush = mdsc->last_cap_flush_tid;
5565 	if (!list_empty(&mdsc->cap_flush_list)) {
5566 		struct ceph_cap_flush *cf =
5567 			list_last_entry(&mdsc->cap_flush_list,
5568 					struct ceph_cap_flush, g_list);
5569 		cf->wake = true;
5570 	}
5571 	spin_unlock(&mdsc->cap_dirty_lock);
5572 
5573 	doutc(cl, "sync want tid %lld flush_seq %lld\n", want_tid, want_flush);
5574 
5575 	flush_mdlog_and_wait_mdsc_unsafe_requests(mdsc, want_tid);
5576 	wait_caps_flush(mdsc, want_flush);
5577 }
5578 
5579 /*
5580  * true if all sessions are closed, or we force unmount
5581  */
5582 static bool done_closing_sessions(struct ceph_mds_client *mdsc, int skipped)
5583 {
5584 	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_SHUTDOWN)
5585 		return true;
5586 	return atomic_read(&mdsc->num_sessions) <= skipped;
5587 }
5588 
5589 /*
5590  * called after sb is ro or when metadata corrupted.
5591  */
5592 void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc)
5593 {
5594 	struct ceph_options *opts = mdsc->fsc->client->options;
5595 	struct ceph_client *cl = mdsc->fsc->client;
5596 	struct ceph_mds_session *session;
5597 	int i;
5598 	int skipped = 0;
5599 
5600 	doutc(cl, "begin\n");
5601 
5602 	/* close sessions */
5603 	mutex_lock(&mdsc->mutex);
5604 	for (i = 0; i < mdsc->max_sessions; i++) {
5605 		session = __ceph_lookup_mds_session(mdsc, i);
5606 		if (!session)
5607 			continue;
5608 		mutex_unlock(&mdsc->mutex);
5609 		mutex_lock(&session->s_mutex);
5610 		if (__close_session(mdsc, session) <= 0)
5611 			skipped++;
5612 		mutex_unlock(&session->s_mutex);
5613 		ceph_put_mds_session(session);
5614 		mutex_lock(&mdsc->mutex);
5615 	}
5616 	mutex_unlock(&mdsc->mutex);
5617 
5618 	doutc(cl, "waiting for sessions to close\n");
5619 	wait_event_timeout(mdsc->session_close_wq,
5620 			   done_closing_sessions(mdsc, skipped),
5621 			   ceph_timeout_jiffies(opts->mount_timeout));
5622 
5623 	/* tear down remaining sessions */
5624 	mutex_lock(&mdsc->mutex);
5625 	for (i = 0; i < mdsc->max_sessions; i++) {
5626 		if (mdsc->sessions[i]) {
5627 			session = ceph_get_mds_session(mdsc->sessions[i]);
5628 			__unregister_session(mdsc, session);
5629 			mutex_unlock(&mdsc->mutex);
5630 			mutex_lock(&session->s_mutex);
5631 			remove_session_caps(session);
5632 			mutex_unlock(&session->s_mutex);
5633 			ceph_put_mds_session(session);
5634 			mutex_lock(&mdsc->mutex);
5635 		}
5636 	}
5637 	WARN_ON(!list_empty(&mdsc->cap_delay_list));
5638 	mutex_unlock(&mdsc->mutex);
5639 
5640 	ceph_cleanup_snapid_map(mdsc);
5641 	ceph_cleanup_global_and_empty_realms(mdsc);
5642 
5643 	cancel_work_sync(&mdsc->cap_reclaim_work);
5644 	cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
5645 
5646 	doutc(cl, "done\n");
5647 }
5648 
5649 void ceph_mdsc_force_umount(struct ceph_mds_client *mdsc)
5650 {
5651 	struct ceph_mds_session *session;
5652 	int mds;
5653 
5654 	doutc(mdsc->fsc->client, "force umount\n");
5655 
5656 	mutex_lock(&mdsc->mutex);
5657 	for (mds = 0; mds < mdsc->max_sessions; mds++) {
5658 		session = __ceph_lookup_mds_session(mdsc, mds);
5659 		if (!session)
5660 			continue;
5661 
5662 		if (session->s_state == CEPH_MDS_SESSION_REJECTED)
5663 			__unregister_session(mdsc, session);
5664 		__wake_requests(mdsc, &session->s_waiting);
5665 		mutex_unlock(&mdsc->mutex);
5666 
5667 		mutex_lock(&session->s_mutex);
5668 		__close_session(mdsc, session);
5669 		if (session->s_state == CEPH_MDS_SESSION_CLOSING) {
5670 			cleanup_session_requests(mdsc, session);
5671 			remove_session_caps(session);
5672 		}
5673 		mutex_unlock(&session->s_mutex);
5674 		ceph_put_mds_session(session);
5675 
5676 		mutex_lock(&mdsc->mutex);
5677 		kick_requests(mdsc, mds);
5678 	}
5679 	__wake_requests(mdsc, &mdsc->waiting_for_map);
5680 	mutex_unlock(&mdsc->mutex);
5681 }
5682 
5683 static void ceph_mdsc_stop(struct ceph_mds_client *mdsc)
5684 {
5685 	doutc(mdsc->fsc->client, "stop\n");
5686 	/*
5687 	 * Make sure the delayed work stopped before releasing
5688 	 * the resources.
5689 	 *
5690 	 * Because the cancel_delayed_work_sync() will only
5691 	 * guarantee that the work finishes executing. But the
5692 	 * delayed work will re-arm itself again after that.
5693 	 */
5694 	flush_delayed_work(&mdsc->delayed_work);
5695 
5696 	if (mdsc->mdsmap)
5697 		ceph_mdsmap_destroy(mdsc->mdsmap);
5698 	kfree(mdsc->sessions);
5699 	ceph_caps_finalize(mdsc);
5700 	ceph_pool_perm_destroy(mdsc);
5701 }
5702 
5703 void ceph_mdsc_destroy(struct ceph_fs_client *fsc)
5704 {
5705 	struct ceph_mds_client *mdsc = fsc->mdsc;
5706 	doutc(fsc->client, "%p\n", mdsc);
5707 
5708 	if (!mdsc)
5709 		return;
5710 
5711 	/* flush out any connection work with references to us */
5712 	ceph_msgr_flush();
5713 
5714 	ceph_mdsc_stop(mdsc);
5715 
5716 	ceph_metric_destroy(&mdsc->metric);
5717 
5718 	fsc->mdsc = NULL;
5719 	kfree(mdsc);
5720 	doutc(fsc->client, "%p done\n", mdsc);
5721 }
5722 
5723 void ceph_mdsc_handle_fsmap(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
5724 {
5725 	struct ceph_fs_client *fsc = mdsc->fsc;
5726 	struct ceph_client *cl = fsc->client;
5727 	const char *mds_namespace = fsc->mount_options->mds_namespace;
5728 	void *p = msg->front.iov_base;
5729 	void *end = p + msg->front.iov_len;
5730 	u32 epoch;
5731 	u32 num_fs;
5732 	u32 mount_fscid = (u32)-1;
5733 	int err = -EINVAL;
5734 
5735 	ceph_decode_need(&p, end, sizeof(u32), bad);
5736 	epoch = ceph_decode_32(&p);
5737 
5738 	doutc(cl, "epoch %u\n", epoch);
5739 
5740 	/* struct_v, struct_cv, map_len, epoch, legacy_client_fscid */
5741 	ceph_decode_skip_n(&p, end, 2 + sizeof(u32) * 3, bad);
5742 
5743 	ceph_decode_32_safe(&p, end, num_fs, bad);
5744 	while (num_fs-- > 0) {
5745 		void *info_p, *info_end;
5746 		u32 info_len;
5747 		u32 fscid, namelen;
5748 
5749 		ceph_decode_need(&p, end, 2 + sizeof(u32), bad);
5750 		p += 2;		// info_v, info_cv
5751 		info_len = ceph_decode_32(&p);
5752 		ceph_decode_need(&p, end, info_len, bad);
5753 		info_p = p;
5754 		info_end = p + info_len;
5755 		p = info_end;
5756 
5757 		ceph_decode_need(&info_p, info_end, sizeof(u32) * 2, bad);
5758 		fscid = ceph_decode_32(&info_p);
5759 		namelen = ceph_decode_32(&info_p);
5760 		ceph_decode_need(&info_p, info_end, namelen, bad);
5761 
5762 		if (mds_namespace &&
5763 		    strlen(mds_namespace) == namelen &&
5764 		    !strncmp(mds_namespace, (char *)info_p, namelen)) {
5765 			mount_fscid = fscid;
5766 			break;
5767 		}
5768 	}
5769 
5770 	ceph_monc_got_map(&fsc->client->monc, CEPH_SUB_FSMAP, epoch);
5771 	if (mount_fscid != (u32)-1) {
5772 		fsc->client->monc.fs_cluster_id = mount_fscid;
5773 		ceph_monc_want_map(&fsc->client->monc, CEPH_SUB_MDSMAP,
5774 				   0, true);
5775 		ceph_monc_renew_subs(&fsc->client->monc);
5776 	} else {
5777 		err = -ENOENT;
5778 		goto err_out;
5779 	}
5780 	return;
5781 
5782 bad:
5783 	pr_err_client(cl, "error decoding fsmap %d. Shutting down mount.\n",
5784 		      err);
5785 	ceph_umount_begin(mdsc->fsc->sb);
5786 	ceph_msg_dump(msg);
5787 err_out:
5788 	mutex_lock(&mdsc->mutex);
5789 	mdsc->mdsmap_err = err;
5790 	__wake_requests(mdsc, &mdsc->waiting_for_map);
5791 	mutex_unlock(&mdsc->mutex);
5792 }
5793 
5794 /*
5795  * handle mds map update.
5796  */
5797 void ceph_mdsc_handle_mdsmap(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
5798 {
5799 	struct ceph_client *cl = mdsc->fsc->client;
5800 	u32 epoch;
5801 	u32 maplen;
5802 	void *p = msg->front.iov_base;
5803 	void *end = p + msg->front.iov_len;
5804 	struct ceph_mdsmap *newmap, *oldmap;
5805 	struct ceph_fsid fsid;
5806 	int err = -EINVAL;
5807 
5808 	ceph_decode_need(&p, end, sizeof(fsid)+2*sizeof(u32), bad);
5809 	ceph_decode_copy(&p, &fsid, sizeof(fsid));
5810 	if (ceph_check_fsid(mdsc->fsc->client, &fsid) < 0)
5811 		return;
5812 	epoch = ceph_decode_32(&p);
5813 	maplen = ceph_decode_32(&p);
5814 	doutc(cl, "epoch %u len %d\n", epoch, (int)maplen);
5815 
5816 	/* do we need it? */
5817 	mutex_lock(&mdsc->mutex);
5818 	if (mdsc->mdsmap && epoch <= mdsc->mdsmap->m_epoch) {
5819 		doutc(cl, "epoch %u <= our %u\n", epoch, mdsc->mdsmap->m_epoch);
5820 		mutex_unlock(&mdsc->mutex);
5821 		return;
5822 	}
5823 
5824 	newmap = ceph_mdsmap_decode(mdsc, &p, end, ceph_msgr2(mdsc->fsc->client));
5825 	if (IS_ERR(newmap)) {
5826 		err = PTR_ERR(newmap);
5827 		goto bad_unlock;
5828 	}
5829 
5830 	/* swap into place */
5831 	if (mdsc->mdsmap) {
5832 		oldmap = mdsc->mdsmap;
5833 		mdsc->mdsmap = newmap;
5834 		check_new_map(mdsc, newmap, oldmap);
5835 		ceph_mdsmap_destroy(oldmap);
5836 	} else {
5837 		mdsc->mdsmap = newmap;  /* first mds map */
5838 	}
5839 	mdsc->fsc->max_file_size = min((loff_t)mdsc->mdsmap->m_max_file_size,
5840 					MAX_LFS_FILESIZE);
5841 
5842 	__wake_requests(mdsc, &mdsc->waiting_for_map);
5843 	ceph_monc_got_map(&mdsc->fsc->client->monc, CEPH_SUB_MDSMAP,
5844 			  mdsc->mdsmap->m_epoch);
5845 
5846 	mutex_unlock(&mdsc->mutex);
5847 	schedule_delayed(mdsc, 0);
5848 	return;
5849 
5850 bad_unlock:
5851 	mutex_unlock(&mdsc->mutex);
5852 bad:
5853 	pr_err_client(cl, "error decoding mdsmap %d. Shutting down mount.\n",
5854 		      err);
5855 	ceph_umount_begin(mdsc->fsc->sb);
5856 	ceph_msg_dump(msg);
5857 	return;
5858 }
5859 
5860 static struct ceph_connection *mds_get_con(struct ceph_connection *con)
5861 {
5862 	struct ceph_mds_session *s = con->private;
5863 
5864 	if (ceph_get_mds_session(s))
5865 		return con;
5866 	return NULL;
5867 }
5868 
5869 static void mds_put_con(struct ceph_connection *con)
5870 {
5871 	struct ceph_mds_session *s = con->private;
5872 
5873 	ceph_put_mds_session(s);
5874 }
5875 
5876 /*
5877  * if the client is unresponsive for long enough, the mds will kill
5878  * the session entirely.
5879  */
5880 static void mds_peer_reset(struct ceph_connection *con)
5881 {
5882 	struct ceph_mds_session *s = con->private;
5883 	struct ceph_mds_client *mdsc = s->s_mdsc;
5884 
5885 	pr_warn_client(mdsc->fsc->client, "mds%d closed our session\n",
5886 		       s->s_mds);
5887 	if (READ_ONCE(mdsc->fsc->mount_state) != CEPH_MOUNT_FENCE_IO &&
5888 	    ceph_mdsmap_get_state(mdsc->mdsmap, s->s_mds) >= CEPH_MDS_STATE_RECONNECT)
5889 		send_mds_reconnect(mdsc, s);
5890 }
5891 
5892 static void mds_dispatch(struct ceph_connection *con, struct ceph_msg *msg)
5893 {
5894 	struct ceph_mds_session *s = con->private;
5895 	struct ceph_mds_client *mdsc = s->s_mdsc;
5896 	struct ceph_client *cl = mdsc->fsc->client;
5897 	int type = le16_to_cpu(msg->hdr.type);
5898 
5899 	mutex_lock(&mdsc->mutex);
5900 	if (__verify_registered_session(mdsc, s) < 0) {
5901 		mutex_unlock(&mdsc->mutex);
5902 		goto out;
5903 	}
5904 	mutex_unlock(&mdsc->mutex);
5905 
5906 	switch (type) {
5907 	case CEPH_MSG_MDS_MAP:
5908 		ceph_mdsc_handle_mdsmap(mdsc, msg);
5909 		break;
5910 	case CEPH_MSG_FS_MAP_USER:
5911 		ceph_mdsc_handle_fsmap(mdsc, msg);
5912 		break;
5913 	case CEPH_MSG_CLIENT_SESSION:
5914 		handle_session(s, msg);
5915 		break;
5916 	case CEPH_MSG_CLIENT_REPLY:
5917 		handle_reply(s, msg);
5918 		break;
5919 	case CEPH_MSG_CLIENT_REQUEST_FORWARD:
5920 		handle_forward(mdsc, s, msg);
5921 		break;
5922 	case CEPH_MSG_CLIENT_CAPS:
5923 		ceph_handle_caps(s, msg);
5924 		break;
5925 	case CEPH_MSG_CLIENT_SNAP:
5926 		ceph_handle_snap(mdsc, s, msg);
5927 		break;
5928 	case CEPH_MSG_CLIENT_LEASE:
5929 		handle_lease(mdsc, s, msg);
5930 		break;
5931 	case CEPH_MSG_CLIENT_QUOTA:
5932 		ceph_handle_quota(mdsc, s, msg);
5933 		break;
5934 
5935 	default:
5936 		pr_err_client(cl, "received unknown message type %d %s\n",
5937 			      type, ceph_msg_type_name(type));
5938 	}
5939 out:
5940 	ceph_msg_put(msg);
5941 }
5942 
5943 /*
5944  * authentication
5945  */
5946 
5947 /*
5948  * Note: returned pointer is the address of a structure that's
5949  * managed separately.  Caller must *not* attempt to free it.
5950  */
5951 static struct ceph_auth_handshake *
5952 mds_get_authorizer(struct ceph_connection *con, int *proto, int force_new)
5953 {
5954 	struct ceph_mds_session *s = con->private;
5955 	struct ceph_mds_client *mdsc = s->s_mdsc;
5956 	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
5957 	struct ceph_auth_handshake *auth = &s->s_auth;
5958 	int ret;
5959 
5960 	ret = __ceph_auth_get_authorizer(ac, auth, CEPH_ENTITY_TYPE_MDS,
5961 					 force_new, proto, NULL, NULL);
5962 	if (ret)
5963 		return ERR_PTR(ret);
5964 
5965 	return auth;
5966 }
5967 
5968 static int mds_add_authorizer_challenge(struct ceph_connection *con,
5969 				    void *challenge_buf, int challenge_buf_len)
5970 {
5971 	struct ceph_mds_session *s = con->private;
5972 	struct ceph_mds_client *mdsc = s->s_mdsc;
5973 	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
5974 
5975 	return ceph_auth_add_authorizer_challenge(ac, s->s_auth.authorizer,
5976 					    challenge_buf, challenge_buf_len);
5977 }
5978 
5979 static int mds_verify_authorizer_reply(struct ceph_connection *con)
5980 {
5981 	struct ceph_mds_session *s = con->private;
5982 	struct ceph_mds_client *mdsc = s->s_mdsc;
5983 	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
5984 	struct ceph_auth_handshake *auth = &s->s_auth;
5985 
5986 	return ceph_auth_verify_authorizer_reply(ac, auth->authorizer,
5987 		auth->authorizer_reply_buf, auth->authorizer_reply_buf_len,
5988 		NULL, NULL, NULL, NULL);
5989 }
5990 
5991 static int mds_invalidate_authorizer(struct ceph_connection *con)
5992 {
5993 	struct ceph_mds_session *s = con->private;
5994 	struct ceph_mds_client *mdsc = s->s_mdsc;
5995 	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
5996 
5997 	ceph_auth_invalidate_authorizer(ac, CEPH_ENTITY_TYPE_MDS);
5998 
5999 	return ceph_monc_validate_auth(&mdsc->fsc->client->monc);
6000 }
6001 
6002 static int mds_get_auth_request(struct ceph_connection *con,
6003 				void *buf, int *buf_len,
6004 				void **authorizer, int *authorizer_len)
6005 {
6006 	struct ceph_mds_session *s = con->private;
6007 	struct ceph_auth_client *ac = s->s_mdsc->fsc->client->monc.auth;
6008 	struct ceph_auth_handshake *auth = &s->s_auth;
6009 	int ret;
6010 
6011 	ret = ceph_auth_get_authorizer(ac, auth, CEPH_ENTITY_TYPE_MDS,
6012 				       buf, buf_len);
6013 	if (ret)
6014 		return ret;
6015 
6016 	*authorizer = auth->authorizer_buf;
6017 	*authorizer_len = auth->authorizer_buf_len;
6018 	return 0;
6019 }
6020 
6021 static int mds_handle_auth_reply_more(struct ceph_connection *con,
6022 				      void *reply, int reply_len,
6023 				      void *buf, int *buf_len,
6024 				      void **authorizer, int *authorizer_len)
6025 {
6026 	struct ceph_mds_session *s = con->private;
6027 	struct ceph_auth_client *ac = s->s_mdsc->fsc->client->monc.auth;
6028 	struct ceph_auth_handshake *auth = &s->s_auth;
6029 	int ret;
6030 
6031 	ret = ceph_auth_handle_svc_reply_more(ac, auth, reply, reply_len,
6032 					      buf, buf_len);
6033 	if (ret)
6034 		return ret;
6035 
6036 	*authorizer = auth->authorizer_buf;
6037 	*authorizer_len = auth->authorizer_buf_len;
6038 	return 0;
6039 }
6040 
6041 static int mds_handle_auth_done(struct ceph_connection *con,
6042 				u64 global_id, void *reply, int reply_len,
6043 				u8 *session_key, int *session_key_len,
6044 				u8 *con_secret, int *con_secret_len)
6045 {
6046 	struct ceph_mds_session *s = con->private;
6047 	struct ceph_auth_client *ac = s->s_mdsc->fsc->client->monc.auth;
6048 	struct ceph_auth_handshake *auth = &s->s_auth;
6049 
6050 	return ceph_auth_handle_svc_reply_done(ac, auth, reply, reply_len,
6051 					       session_key, session_key_len,
6052 					       con_secret, con_secret_len);
6053 }
6054 
6055 static int mds_handle_auth_bad_method(struct ceph_connection *con,
6056 				      int used_proto, int result,
6057 				      const int *allowed_protos, int proto_cnt,
6058 				      const int *allowed_modes, int mode_cnt)
6059 {
6060 	struct ceph_mds_session *s = con->private;
6061 	struct ceph_mon_client *monc = &s->s_mdsc->fsc->client->monc;
6062 	int ret;
6063 
6064 	if (ceph_auth_handle_bad_authorizer(monc->auth, CEPH_ENTITY_TYPE_MDS,
6065 					    used_proto, result,
6066 					    allowed_protos, proto_cnt,
6067 					    allowed_modes, mode_cnt)) {
6068 		ret = ceph_monc_validate_auth(monc);
6069 		if (ret)
6070 			return ret;
6071 	}
6072 
6073 	return -EACCES;
6074 }
6075 
6076 static struct ceph_msg *mds_alloc_msg(struct ceph_connection *con,
6077 				struct ceph_msg_header *hdr, int *skip)
6078 {
6079 	struct ceph_msg *msg;
6080 	int type = (int) le16_to_cpu(hdr->type);
6081 	int front_len = (int) le32_to_cpu(hdr->front_len);
6082 
6083 	if (con->in_msg)
6084 		return con->in_msg;
6085 
6086 	*skip = 0;
6087 	msg = ceph_msg_new(type, front_len, GFP_NOFS, false);
6088 	if (!msg) {
6089 		pr_err("unable to allocate msg type %d len %d\n",
6090 		       type, front_len);
6091 		return NULL;
6092 	}
6093 
6094 	return msg;
6095 }
6096 
6097 static int mds_sign_message(struct ceph_msg *msg)
6098 {
6099        struct ceph_mds_session *s = msg->con->private;
6100        struct ceph_auth_handshake *auth = &s->s_auth;
6101 
6102        return ceph_auth_sign_message(auth, msg);
6103 }
6104 
6105 static int mds_check_message_signature(struct ceph_msg *msg)
6106 {
6107        struct ceph_mds_session *s = msg->con->private;
6108        struct ceph_auth_handshake *auth = &s->s_auth;
6109 
6110        return ceph_auth_check_message_signature(auth, msg);
6111 }
6112 
6113 static const struct ceph_connection_operations mds_con_ops = {
6114 	.get = mds_get_con,
6115 	.put = mds_put_con,
6116 	.alloc_msg = mds_alloc_msg,
6117 	.dispatch = mds_dispatch,
6118 	.peer_reset = mds_peer_reset,
6119 	.get_authorizer = mds_get_authorizer,
6120 	.add_authorizer_challenge = mds_add_authorizer_challenge,
6121 	.verify_authorizer_reply = mds_verify_authorizer_reply,
6122 	.invalidate_authorizer = mds_invalidate_authorizer,
6123 	.sign_message = mds_sign_message,
6124 	.check_message_signature = mds_check_message_signature,
6125 	.get_auth_request = mds_get_auth_request,
6126 	.handle_auth_reply_more = mds_handle_auth_reply_more,
6127 	.handle_auth_done = mds_handle_auth_done,
6128 	.handle_auth_bad_method = mds_handle_auth_bad_method,
6129 };
6130 
6131 /* eof */
6132