xref: /linux/fs/ceph/mds_client.c (revision 94f17c00d6687993101372f996cf6690ec9adf83)
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 
15 #include "super.h"
16 #include "mds_client.h"
17 
18 #include <linux/ceph/ceph_features.h>
19 #include <linux/ceph/messenger.h>
20 #include <linux/ceph/decode.h>
21 #include <linux/ceph/pagelist.h>
22 #include <linux/ceph/auth.h>
23 #include <linux/ceph/debugfs.h>
24 
25 #define RECONNECT_MAX_SIZE (INT_MAX - PAGE_SIZE)
26 
27 /*
28  * A cluster of MDS (metadata server) daemons is responsible for
29  * managing the file system namespace (the directory hierarchy and
30  * inodes) and for coordinating shared access to storage.  Metadata is
31  * partitioning hierarchically across a number of servers, and that
32  * partition varies over time as the cluster adjusts the distribution
33  * in order to balance load.
34  *
35  * The MDS client is primarily responsible to managing synchronous
36  * metadata requests for operations like open, unlink, and so forth.
37  * If there is a MDS failure, we find out about it when we (possibly
38  * request and) receive a new MDS map, and can resubmit affected
39  * requests.
40  *
41  * For the most part, though, we take advantage of a lossless
42  * communications channel to the MDS, and do not need to worry about
43  * timing out or resubmitting requests.
44  *
45  * We maintain a stateful "session" with each MDS we interact with.
46  * Within each session, we sent periodic heartbeat messages to ensure
47  * any capabilities or leases we have been issues remain valid.  If
48  * the session times out and goes stale, our leases and capabilities
49  * are no longer valid.
50  */
51 
52 struct ceph_reconnect_state {
53 	struct ceph_mds_session *session;
54 	int nr_caps, nr_realms;
55 	struct ceph_pagelist *pagelist;
56 	unsigned msg_version;
57 	bool allow_multi;
58 };
59 
60 static void __wake_requests(struct ceph_mds_client *mdsc,
61 			    struct list_head *head);
62 static void ceph_cap_release_work(struct work_struct *work);
63 static void ceph_cap_reclaim_work(struct work_struct *work);
64 
65 static const struct ceph_connection_operations mds_con_ops;
66 
67 
68 /*
69  * mds reply parsing
70  */
71 
72 static int parse_reply_info_quota(void **p, void *end,
73 				  struct ceph_mds_reply_info_in *info)
74 {
75 	u8 struct_v, struct_compat;
76 	u32 struct_len;
77 
78 	ceph_decode_8_safe(p, end, struct_v, bad);
79 	ceph_decode_8_safe(p, end, struct_compat, bad);
80 	/* struct_v is expected to be >= 1. we only
81 	 * understand encoding with struct_compat == 1. */
82 	if (!struct_v || struct_compat != 1)
83 		goto bad;
84 	ceph_decode_32_safe(p, end, struct_len, bad);
85 	ceph_decode_need(p, end, struct_len, bad);
86 	end = *p + struct_len;
87 	ceph_decode_64_safe(p, end, info->max_bytes, bad);
88 	ceph_decode_64_safe(p, end, info->max_files, bad);
89 	*p = end;
90 	return 0;
91 bad:
92 	return -EIO;
93 }
94 
95 /*
96  * parse individual inode info
97  */
98 static int parse_reply_info_in(void **p, void *end,
99 			       struct ceph_mds_reply_info_in *info,
100 			       u64 features)
101 {
102 	int err = 0;
103 	u8 struct_v = 0;
104 
105 	if (features == (u64)-1) {
106 		u32 struct_len;
107 		u8 struct_compat;
108 		ceph_decode_8_safe(p, end, struct_v, bad);
109 		ceph_decode_8_safe(p, end, struct_compat, bad);
110 		/* struct_v is expected to be >= 1. we only understand
111 		 * encoding with struct_compat == 1. */
112 		if (!struct_v || struct_compat != 1)
113 			goto bad;
114 		ceph_decode_32_safe(p, end, struct_len, bad);
115 		ceph_decode_need(p, end, struct_len, bad);
116 		end = *p + struct_len;
117 	}
118 
119 	ceph_decode_need(p, end, sizeof(struct ceph_mds_reply_inode), bad);
120 	info->in = *p;
121 	*p += sizeof(struct ceph_mds_reply_inode) +
122 		sizeof(*info->in->fragtree.splits) *
123 		le32_to_cpu(info->in->fragtree.nsplits);
124 
125 	ceph_decode_32_safe(p, end, info->symlink_len, bad);
126 	ceph_decode_need(p, end, info->symlink_len, bad);
127 	info->symlink = *p;
128 	*p += info->symlink_len;
129 
130 	ceph_decode_copy_safe(p, end, &info->dir_layout,
131 			      sizeof(info->dir_layout), bad);
132 	ceph_decode_32_safe(p, end, info->xattr_len, bad);
133 	ceph_decode_need(p, end, info->xattr_len, bad);
134 	info->xattr_data = *p;
135 	*p += info->xattr_len;
136 
137 	if (features == (u64)-1) {
138 		/* inline data */
139 		ceph_decode_64_safe(p, end, info->inline_version, bad);
140 		ceph_decode_32_safe(p, end, info->inline_len, bad);
141 		ceph_decode_need(p, end, info->inline_len, bad);
142 		info->inline_data = *p;
143 		*p += info->inline_len;
144 		/* quota */
145 		err = parse_reply_info_quota(p, end, info);
146 		if (err < 0)
147 			goto out_bad;
148 		/* pool namespace */
149 		ceph_decode_32_safe(p, end, info->pool_ns_len, bad);
150 		if (info->pool_ns_len > 0) {
151 			ceph_decode_need(p, end, info->pool_ns_len, bad);
152 			info->pool_ns_data = *p;
153 			*p += info->pool_ns_len;
154 		}
155 
156 		/* btime */
157 		ceph_decode_need(p, end, sizeof(info->btime), bad);
158 		ceph_decode_copy(p, &info->btime, sizeof(info->btime));
159 
160 		/* change attribute */
161 		ceph_decode_64_safe(p, end, info->change_attr, bad);
162 
163 		/* dir pin */
164 		if (struct_v >= 2) {
165 			ceph_decode_32_safe(p, end, info->dir_pin, bad);
166 		} else {
167 			info->dir_pin = -ENODATA;
168 		}
169 
170 		/* snapshot birth time, remains zero for v<=2 */
171 		if (struct_v >= 3) {
172 			ceph_decode_need(p, end, sizeof(info->snap_btime), bad);
173 			ceph_decode_copy(p, &info->snap_btime,
174 					 sizeof(info->snap_btime));
175 		} else {
176 			memset(&info->snap_btime, 0, sizeof(info->snap_btime));
177 		}
178 
179 		*p = end;
180 	} else {
181 		if (features & CEPH_FEATURE_MDS_INLINE_DATA) {
182 			ceph_decode_64_safe(p, end, info->inline_version, bad);
183 			ceph_decode_32_safe(p, end, info->inline_len, bad);
184 			ceph_decode_need(p, end, info->inline_len, bad);
185 			info->inline_data = *p;
186 			*p += info->inline_len;
187 		} else
188 			info->inline_version = CEPH_INLINE_NONE;
189 
190 		if (features & CEPH_FEATURE_MDS_QUOTA) {
191 			err = parse_reply_info_quota(p, end, info);
192 			if (err < 0)
193 				goto out_bad;
194 		} else {
195 			info->max_bytes = 0;
196 			info->max_files = 0;
197 		}
198 
199 		info->pool_ns_len = 0;
200 		info->pool_ns_data = NULL;
201 		if (features & CEPH_FEATURE_FS_FILE_LAYOUT_V2) {
202 			ceph_decode_32_safe(p, end, info->pool_ns_len, bad);
203 			if (info->pool_ns_len > 0) {
204 				ceph_decode_need(p, end, info->pool_ns_len, bad);
205 				info->pool_ns_data = *p;
206 				*p += info->pool_ns_len;
207 			}
208 		}
209 
210 		if (features & CEPH_FEATURE_FS_BTIME) {
211 			ceph_decode_need(p, end, sizeof(info->btime), bad);
212 			ceph_decode_copy(p, &info->btime, sizeof(info->btime));
213 			ceph_decode_64_safe(p, end, info->change_attr, bad);
214 		}
215 
216 		info->dir_pin = -ENODATA;
217 		/* info->snap_btime remains zero */
218 	}
219 	return 0;
220 bad:
221 	err = -EIO;
222 out_bad:
223 	return err;
224 }
225 
226 static int parse_reply_info_dir(void **p, void *end,
227 				struct ceph_mds_reply_dirfrag **dirfrag,
228 				u64 features)
229 {
230 	if (features == (u64)-1) {
231 		u8 struct_v, struct_compat;
232 		u32 struct_len;
233 		ceph_decode_8_safe(p, end, struct_v, bad);
234 		ceph_decode_8_safe(p, end, struct_compat, bad);
235 		/* struct_v is expected to be >= 1. we only understand
236 		 * encoding whose struct_compat == 1. */
237 		if (!struct_v || struct_compat != 1)
238 			goto bad;
239 		ceph_decode_32_safe(p, end, struct_len, bad);
240 		ceph_decode_need(p, end, struct_len, bad);
241 		end = *p + struct_len;
242 	}
243 
244 	ceph_decode_need(p, end, sizeof(**dirfrag), bad);
245 	*dirfrag = *p;
246 	*p += sizeof(**dirfrag) + sizeof(u32) * le32_to_cpu((*dirfrag)->ndist);
247 	if (unlikely(*p > end))
248 		goto bad;
249 	if (features == (u64)-1)
250 		*p = end;
251 	return 0;
252 bad:
253 	return -EIO;
254 }
255 
256 static int parse_reply_info_lease(void **p, void *end,
257 				  struct ceph_mds_reply_lease **lease,
258 				  u64 features)
259 {
260 	if (features == (u64)-1) {
261 		u8 struct_v, struct_compat;
262 		u32 struct_len;
263 		ceph_decode_8_safe(p, end, struct_v, bad);
264 		ceph_decode_8_safe(p, end, struct_compat, bad);
265 		/* struct_v is expected to be >= 1. we only understand
266 		 * encoding whose struct_compat == 1. */
267 		if (!struct_v || struct_compat != 1)
268 			goto bad;
269 		ceph_decode_32_safe(p, end, struct_len, bad);
270 		ceph_decode_need(p, end, struct_len, bad);
271 		end = *p + struct_len;
272 	}
273 
274 	ceph_decode_need(p, end, sizeof(**lease), bad);
275 	*lease = *p;
276 	*p += sizeof(**lease);
277 	if (features == (u64)-1)
278 		*p = end;
279 	return 0;
280 bad:
281 	return -EIO;
282 }
283 
284 /*
285  * parse a normal reply, which may contain a (dir+)dentry and/or a
286  * target inode.
287  */
288 static int parse_reply_info_trace(void **p, void *end,
289 				  struct ceph_mds_reply_info_parsed *info,
290 				  u64 features)
291 {
292 	int err;
293 
294 	if (info->head->is_dentry) {
295 		err = parse_reply_info_in(p, end, &info->diri, features);
296 		if (err < 0)
297 			goto out_bad;
298 
299 		err = parse_reply_info_dir(p, end, &info->dirfrag, features);
300 		if (err < 0)
301 			goto out_bad;
302 
303 		ceph_decode_32_safe(p, end, info->dname_len, bad);
304 		ceph_decode_need(p, end, info->dname_len, bad);
305 		info->dname = *p;
306 		*p += info->dname_len;
307 
308 		err = parse_reply_info_lease(p, end, &info->dlease, features);
309 		if (err < 0)
310 			goto out_bad;
311 	}
312 
313 	if (info->head->is_target) {
314 		err = parse_reply_info_in(p, end, &info->targeti, features);
315 		if (err < 0)
316 			goto out_bad;
317 	}
318 
319 	if (unlikely(*p != end))
320 		goto bad;
321 	return 0;
322 
323 bad:
324 	err = -EIO;
325 out_bad:
326 	pr_err("problem parsing mds trace %d\n", err);
327 	return err;
328 }
329 
330 /*
331  * parse readdir results
332  */
333 static int parse_reply_info_readdir(void **p, void *end,
334 				struct ceph_mds_reply_info_parsed *info,
335 				u64 features)
336 {
337 	u32 num, i = 0;
338 	int err;
339 
340 	err = parse_reply_info_dir(p, end, &info->dir_dir, features);
341 	if (err < 0)
342 		goto out_bad;
343 
344 	ceph_decode_need(p, end, sizeof(num) + 2, bad);
345 	num = ceph_decode_32(p);
346 	{
347 		u16 flags = ceph_decode_16(p);
348 		info->dir_end = !!(flags & CEPH_READDIR_FRAG_END);
349 		info->dir_complete = !!(flags & CEPH_READDIR_FRAG_COMPLETE);
350 		info->hash_order = !!(flags & CEPH_READDIR_HASH_ORDER);
351 		info->offset_hash = !!(flags & CEPH_READDIR_OFFSET_HASH);
352 	}
353 	if (num == 0)
354 		goto done;
355 
356 	BUG_ON(!info->dir_entries);
357 	if ((unsigned long)(info->dir_entries + num) >
358 	    (unsigned long)info->dir_entries + info->dir_buf_size) {
359 		pr_err("dir contents are larger than expected\n");
360 		WARN_ON(1);
361 		goto bad;
362 	}
363 
364 	info->dir_nr = num;
365 	while (num) {
366 		struct ceph_mds_reply_dir_entry *rde = info->dir_entries + i;
367 		/* dentry */
368 		ceph_decode_32_safe(p, end, rde->name_len, bad);
369 		ceph_decode_need(p, end, rde->name_len, bad);
370 		rde->name = *p;
371 		*p += rde->name_len;
372 		dout("parsed dir dname '%.*s'\n", rde->name_len, rde->name);
373 
374 		/* dentry lease */
375 		err = parse_reply_info_lease(p, end, &rde->lease, features);
376 		if (err)
377 			goto out_bad;
378 		/* inode */
379 		err = parse_reply_info_in(p, end, &rde->inode, features);
380 		if (err < 0)
381 			goto out_bad;
382 		/* ceph_readdir_prepopulate() will update it */
383 		rde->offset = 0;
384 		i++;
385 		num--;
386 	}
387 
388 done:
389 	/* Skip over any unrecognized fields */
390 	*p = end;
391 	return 0;
392 
393 bad:
394 	err = -EIO;
395 out_bad:
396 	pr_err("problem parsing dir contents %d\n", err);
397 	return err;
398 }
399 
400 /*
401  * parse fcntl F_GETLK results
402  */
403 static int parse_reply_info_filelock(void **p, void *end,
404 				     struct ceph_mds_reply_info_parsed *info,
405 				     u64 features)
406 {
407 	if (*p + sizeof(*info->filelock_reply) > end)
408 		goto bad;
409 
410 	info->filelock_reply = *p;
411 
412 	/* Skip over any unrecognized fields */
413 	*p = end;
414 	return 0;
415 bad:
416 	return -EIO;
417 }
418 
419 
420 #if BITS_PER_LONG == 64
421 
422 #define DELEGATED_INO_AVAILABLE		xa_mk_value(1)
423 
424 static int ceph_parse_deleg_inos(void **p, void *end,
425 				 struct ceph_mds_session *s)
426 {
427 	u32 sets;
428 
429 	ceph_decode_32_safe(p, end, sets, bad);
430 	dout("got %u sets of delegated inodes\n", sets);
431 	while (sets--) {
432 		u64 start, len, ino;
433 
434 		ceph_decode_64_safe(p, end, start, bad);
435 		ceph_decode_64_safe(p, end, len, bad);
436 		while (len--) {
437 			int err = xa_insert(&s->s_delegated_inos, ino = start++,
438 					    DELEGATED_INO_AVAILABLE,
439 					    GFP_KERNEL);
440 			if (!err) {
441 				dout("added delegated inode 0x%llx\n",
442 				     start - 1);
443 			} else if (err == -EBUSY) {
444 				pr_warn("ceph: MDS delegated inode 0x%llx more than once.\n",
445 					start - 1);
446 			} else {
447 				return err;
448 			}
449 		}
450 	}
451 	return 0;
452 bad:
453 	return -EIO;
454 }
455 
456 u64 ceph_get_deleg_ino(struct ceph_mds_session *s)
457 {
458 	unsigned long ino;
459 	void *val;
460 
461 	xa_for_each(&s->s_delegated_inos, ino, val) {
462 		val = xa_erase(&s->s_delegated_inos, ino);
463 		if (val == DELEGATED_INO_AVAILABLE)
464 			return ino;
465 	}
466 	return 0;
467 }
468 
469 int ceph_restore_deleg_ino(struct ceph_mds_session *s, u64 ino)
470 {
471 	return xa_insert(&s->s_delegated_inos, ino, DELEGATED_INO_AVAILABLE,
472 			 GFP_KERNEL);
473 }
474 #else /* BITS_PER_LONG == 64 */
475 /*
476  * FIXME: xarrays can't handle 64-bit indexes on a 32-bit arch. For now, just
477  * ignore delegated_inos on 32 bit arch. Maybe eventually add xarrays for top
478  * and bottom words?
479  */
480 static int ceph_parse_deleg_inos(void **p, void *end,
481 				 struct ceph_mds_session *s)
482 {
483 	u32 sets;
484 
485 	ceph_decode_32_safe(p, end, sets, bad);
486 	if (sets)
487 		ceph_decode_skip_n(p, end, sets * 2 * sizeof(__le64), bad);
488 	return 0;
489 bad:
490 	return -EIO;
491 }
492 
493 u64 ceph_get_deleg_ino(struct ceph_mds_session *s)
494 {
495 	return 0;
496 }
497 
498 int ceph_restore_deleg_ino(struct ceph_mds_session *s, u64 ino)
499 {
500 	return 0;
501 }
502 #endif /* BITS_PER_LONG == 64 */
503 
504 /*
505  * parse create results
506  */
507 static int parse_reply_info_create(void **p, void *end,
508 				  struct ceph_mds_reply_info_parsed *info,
509 				  u64 features, struct ceph_mds_session *s)
510 {
511 	int ret;
512 
513 	if (features == (u64)-1 ||
514 	    (features & CEPH_FEATURE_REPLY_CREATE_INODE)) {
515 		if (*p == end) {
516 			/* Malformed reply? */
517 			info->has_create_ino = false;
518 		} else if (test_bit(CEPHFS_FEATURE_DELEG_INO, &s->s_features)) {
519 			u8 struct_v, struct_compat;
520 			u32 len;
521 
522 			info->has_create_ino = true;
523 			ceph_decode_8_safe(p, end, struct_v, bad);
524 			ceph_decode_8_safe(p, end, struct_compat, bad);
525 			ceph_decode_32_safe(p, end, len, bad);
526 			ceph_decode_64_safe(p, end, info->ino, bad);
527 			ret = ceph_parse_deleg_inos(p, end, s);
528 			if (ret)
529 				return ret;
530 		} else {
531 			/* legacy */
532 			ceph_decode_64_safe(p, end, info->ino, bad);
533 			info->has_create_ino = true;
534 		}
535 	} else {
536 		if (*p != end)
537 			goto bad;
538 	}
539 
540 	/* Skip over any unrecognized fields */
541 	*p = end;
542 	return 0;
543 bad:
544 	return -EIO;
545 }
546 
547 /*
548  * parse extra results
549  */
550 static int parse_reply_info_extra(void **p, void *end,
551 				  struct ceph_mds_reply_info_parsed *info,
552 				  u64 features, struct ceph_mds_session *s)
553 {
554 	u32 op = le32_to_cpu(info->head->op);
555 
556 	if (op == CEPH_MDS_OP_GETFILELOCK)
557 		return parse_reply_info_filelock(p, end, info, features);
558 	else if (op == CEPH_MDS_OP_READDIR || op == CEPH_MDS_OP_LSSNAP)
559 		return parse_reply_info_readdir(p, end, info, features);
560 	else if (op == CEPH_MDS_OP_CREATE)
561 		return parse_reply_info_create(p, end, info, features, s);
562 	else
563 		return -EIO;
564 }
565 
566 /*
567  * parse entire mds reply
568  */
569 static int parse_reply_info(struct ceph_mds_session *s, struct ceph_msg *msg,
570 			    struct ceph_mds_reply_info_parsed *info,
571 			    u64 features)
572 {
573 	void *p, *end;
574 	u32 len;
575 	int err;
576 
577 	info->head = msg->front.iov_base;
578 	p = msg->front.iov_base + sizeof(struct ceph_mds_reply_head);
579 	end = p + msg->front.iov_len - sizeof(struct ceph_mds_reply_head);
580 
581 	/* trace */
582 	ceph_decode_32_safe(&p, end, len, bad);
583 	if (len > 0) {
584 		ceph_decode_need(&p, end, len, bad);
585 		err = parse_reply_info_trace(&p, p+len, info, features);
586 		if (err < 0)
587 			goto out_bad;
588 	}
589 
590 	/* extra */
591 	ceph_decode_32_safe(&p, end, len, bad);
592 	if (len > 0) {
593 		ceph_decode_need(&p, end, len, bad);
594 		err = parse_reply_info_extra(&p, p+len, info, features, s);
595 		if (err < 0)
596 			goto out_bad;
597 	}
598 
599 	/* snap blob */
600 	ceph_decode_32_safe(&p, end, len, bad);
601 	info->snapblob_len = len;
602 	info->snapblob = p;
603 	p += len;
604 
605 	if (p != end)
606 		goto bad;
607 	return 0;
608 
609 bad:
610 	err = -EIO;
611 out_bad:
612 	pr_err("mds parse_reply err %d\n", err);
613 	return err;
614 }
615 
616 static void destroy_reply_info(struct ceph_mds_reply_info_parsed *info)
617 {
618 	if (!info->dir_entries)
619 		return;
620 	free_pages((unsigned long)info->dir_entries, get_order(info->dir_buf_size));
621 }
622 
623 
624 /*
625  * sessions
626  */
627 const char *ceph_session_state_name(int s)
628 {
629 	switch (s) {
630 	case CEPH_MDS_SESSION_NEW: return "new";
631 	case CEPH_MDS_SESSION_OPENING: return "opening";
632 	case CEPH_MDS_SESSION_OPEN: return "open";
633 	case CEPH_MDS_SESSION_HUNG: return "hung";
634 	case CEPH_MDS_SESSION_CLOSING: return "closing";
635 	case CEPH_MDS_SESSION_CLOSED: return "closed";
636 	case CEPH_MDS_SESSION_RESTARTING: return "restarting";
637 	case CEPH_MDS_SESSION_RECONNECTING: return "reconnecting";
638 	case CEPH_MDS_SESSION_REJECTED: return "rejected";
639 	default: return "???";
640 	}
641 }
642 
643 struct ceph_mds_session *ceph_get_mds_session(struct ceph_mds_session *s)
644 {
645 	if (refcount_inc_not_zero(&s->s_ref)) {
646 		dout("mdsc get_session %p %d -> %d\n", s,
647 		     refcount_read(&s->s_ref)-1, refcount_read(&s->s_ref));
648 		return s;
649 	} else {
650 		dout("mdsc get_session %p 0 -- FAIL\n", s);
651 		return NULL;
652 	}
653 }
654 
655 void ceph_put_mds_session(struct ceph_mds_session *s)
656 {
657 	dout("mdsc put_session %p %d -> %d\n", s,
658 	     refcount_read(&s->s_ref), refcount_read(&s->s_ref)-1);
659 	if (refcount_dec_and_test(&s->s_ref)) {
660 		if (s->s_auth.authorizer)
661 			ceph_auth_destroy_authorizer(s->s_auth.authorizer);
662 		WARN_ON(mutex_is_locked(&s->s_mutex));
663 		xa_destroy(&s->s_delegated_inos);
664 		kfree(s);
665 	}
666 }
667 
668 /*
669  * called under mdsc->mutex
670  */
671 struct ceph_mds_session *__ceph_lookup_mds_session(struct ceph_mds_client *mdsc,
672 						   int mds)
673 {
674 	if (mds >= mdsc->max_sessions || !mdsc->sessions[mds])
675 		return NULL;
676 	return ceph_get_mds_session(mdsc->sessions[mds]);
677 }
678 
679 static bool __have_session(struct ceph_mds_client *mdsc, int mds)
680 {
681 	if (mds >= mdsc->max_sessions || !mdsc->sessions[mds])
682 		return false;
683 	else
684 		return true;
685 }
686 
687 static int __verify_registered_session(struct ceph_mds_client *mdsc,
688 				       struct ceph_mds_session *s)
689 {
690 	if (s->s_mds >= mdsc->max_sessions ||
691 	    mdsc->sessions[s->s_mds] != s)
692 		return -ENOENT;
693 	return 0;
694 }
695 
696 /*
697  * create+register a new session for given mds.
698  * called under mdsc->mutex.
699  */
700 static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
701 						 int mds)
702 {
703 	struct ceph_mds_session *s;
704 
705 	if (mds >= mdsc->mdsmap->possible_max_rank)
706 		return ERR_PTR(-EINVAL);
707 
708 	s = kzalloc(sizeof(*s), GFP_NOFS);
709 	if (!s)
710 		return ERR_PTR(-ENOMEM);
711 
712 	if (mds >= mdsc->max_sessions) {
713 		int newmax = 1 << get_count_order(mds + 1);
714 		struct ceph_mds_session **sa;
715 
716 		dout("%s: realloc to %d\n", __func__, newmax);
717 		sa = kcalloc(newmax, sizeof(void *), GFP_NOFS);
718 		if (!sa)
719 			goto fail_realloc;
720 		if (mdsc->sessions) {
721 			memcpy(sa, mdsc->sessions,
722 			       mdsc->max_sessions * sizeof(void *));
723 			kfree(mdsc->sessions);
724 		}
725 		mdsc->sessions = sa;
726 		mdsc->max_sessions = newmax;
727 	}
728 
729 	dout("%s: mds%d\n", __func__, mds);
730 	s->s_mdsc = mdsc;
731 	s->s_mds = mds;
732 	s->s_state = CEPH_MDS_SESSION_NEW;
733 	s->s_ttl = 0;
734 	s->s_seq = 0;
735 	mutex_init(&s->s_mutex);
736 
737 	ceph_con_init(&s->s_con, s, &mds_con_ops, &mdsc->fsc->client->msgr);
738 
739 	spin_lock_init(&s->s_gen_ttl_lock);
740 	s->s_cap_gen = 1;
741 	s->s_cap_ttl = jiffies - 1;
742 
743 	spin_lock_init(&s->s_cap_lock);
744 	s->s_renew_requested = 0;
745 	s->s_renew_seq = 0;
746 	INIT_LIST_HEAD(&s->s_caps);
747 	s->s_nr_caps = 0;
748 	refcount_set(&s->s_ref, 1);
749 	INIT_LIST_HEAD(&s->s_waiting);
750 	INIT_LIST_HEAD(&s->s_unsafe);
751 	xa_init(&s->s_delegated_inos);
752 	s->s_num_cap_releases = 0;
753 	s->s_cap_reconnect = 0;
754 	s->s_cap_iterator = NULL;
755 	INIT_LIST_HEAD(&s->s_cap_releases);
756 	INIT_WORK(&s->s_cap_release_work, ceph_cap_release_work);
757 
758 	INIT_LIST_HEAD(&s->s_cap_dirty);
759 	INIT_LIST_HEAD(&s->s_cap_flushing);
760 
761 	mdsc->sessions[mds] = s;
762 	atomic_inc(&mdsc->num_sessions);
763 	refcount_inc(&s->s_ref);  /* one ref to sessions[], one to caller */
764 
765 	ceph_con_open(&s->s_con, CEPH_ENTITY_TYPE_MDS, mds,
766 		      ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
767 
768 	return s;
769 
770 fail_realloc:
771 	kfree(s);
772 	return ERR_PTR(-ENOMEM);
773 }
774 
775 /*
776  * called under mdsc->mutex
777  */
778 static void __unregister_session(struct ceph_mds_client *mdsc,
779 			       struct ceph_mds_session *s)
780 {
781 	dout("__unregister_session mds%d %p\n", s->s_mds, s);
782 	BUG_ON(mdsc->sessions[s->s_mds] != s);
783 	mdsc->sessions[s->s_mds] = NULL;
784 	ceph_con_close(&s->s_con);
785 	ceph_put_mds_session(s);
786 	atomic_dec(&mdsc->num_sessions);
787 }
788 
789 /*
790  * drop session refs in request.
791  *
792  * should be last request ref, or hold mdsc->mutex
793  */
794 static void put_request_session(struct ceph_mds_request *req)
795 {
796 	if (req->r_session) {
797 		ceph_put_mds_session(req->r_session);
798 		req->r_session = NULL;
799 	}
800 }
801 
802 void ceph_mdsc_release_request(struct kref *kref)
803 {
804 	struct ceph_mds_request *req = container_of(kref,
805 						    struct ceph_mds_request,
806 						    r_kref);
807 	ceph_mdsc_release_dir_caps_no_check(req);
808 	destroy_reply_info(&req->r_reply_info);
809 	if (req->r_request)
810 		ceph_msg_put(req->r_request);
811 	if (req->r_reply)
812 		ceph_msg_put(req->r_reply);
813 	if (req->r_inode) {
814 		ceph_put_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
815 		/* avoid calling iput_final() in mds dispatch threads */
816 		ceph_async_iput(req->r_inode);
817 	}
818 	if (req->r_parent) {
819 		ceph_put_cap_refs(ceph_inode(req->r_parent), CEPH_CAP_PIN);
820 		ceph_async_iput(req->r_parent);
821 	}
822 	ceph_async_iput(req->r_target_inode);
823 	if (req->r_dentry)
824 		dput(req->r_dentry);
825 	if (req->r_old_dentry)
826 		dput(req->r_old_dentry);
827 	if (req->r_old_dentry_dir) {
828 		/*
829 		 * track (and drop pins for) r_old_dentry_dir
830 		 * separately, since r_old_dentry's d_parent may have
831 		 * changed between the dir mutex being dropped and
832 		 * this request being freed.
833 		 */
834 		ceph_put_cap_refs(ceph_inode(req->r_old_dentry_dir),
835 				  CEPH_CAP_PIN);
836 		ceph_async_iput(req->r_old_dentry_dir);
837 	}
838 	kfree(req->r_path1);
839 	kfree(req->r_path2);
840 	if (req->r_pagelist)
841 		ceph_pagelist_release(req->r_pagelist);
842 	put_request_session(req);
843 	ceph_unreserve_caps(req->r_mdsc, &req->r_caps_reservation);
844 	WARN_ON_ONCE(!list_empty(&req->r_wait));
845 	kmem_cache_free(ceph_mds_request_cachep, req);
846 }
847 
848 DEFINE_RB_FUNCS(request, struct ceph_mds_request, r_tid, r_node)
849 
850 /*
851  * lookup session, bump ref if found.
852  *
853  * called under mdsc->mutex.
854  */
855 static struct ceph_mds_request *
856 lookup_get_request(struct ceph_mds_client *mdsc, u64 tid)
857 {
858 	struct ceph_mds_request *req;
859 
860 	req = lookup_request(&mdsc->request_tree, tid);
861 	if (req)
862 		ceph_mdsc_get_request(req);
863 
864 	return req;
865 }
866 
867 /*
868  * Register an in-flight request, and assign a tid.  Link to directory
869  * are modifying (if any).
870  *
871  * Called under mdsc->mutex.
872  */
873 static void __register_request(struct ceph_mds_client *mdsc,
874 			       struct ceph_mds_request *req,
875 			       struct inode *dir)
876 {
877 	int ret = 0;
878 
879 	req->r_tid = ++mdsc->last_tid;
880 	if (req->r_num_caps) {
881 		ret = ceph_reserve_caps(mdsc, &req->r_caps_reservation,
882 					req->r_num_caps);
883 		if (ret < 0) {
884 			pr_err("__register_request %p "
885 			       "failed to reserve caps: %d\n", req, ret);
886 			/* set req->r_err to fail early from __do_request */
887 			req->r_err = ret;
888 			return;
889 		}
890 	}
891 	dout("__register_request %p tid %lld\n", req, req->r_tid);
892 	ceph_mdsc_get_request(req);
893 	insert_request(&mdsc->request_tree, req);
894 
895 	req->r_uid = current_fsuid();
896 	req->r_gid = current_fsgid();
897 
898 	if (mdsc->oldest_tid == 0 && req->r_op != CEPH_MDS_OP_SETFILELOCK)
899 		mdsc->oldest_tid = req->r_tid;
900 
901 	if (dir) {
902 		struct ceph_inode_info *ci = ceph_inode(dir);
903 
904 		ihold(dir);
905 		req->r_unsafe_dir = dir;
906 		spin_lock(&ci->i_unsafe_lock);
907 		list_add_tail(&req->r_unsafe_dir_item, &ci->i_unsafe_dirops);
908 		spin_unlock(&ci->i_unsafe_lock);
909 	}
910 }
911 
912 static void __unregister_request(struct ceph_mds_client *mdsc,
913 				 struct ceph_mds_request *req)
914 {
915 	dout("__unregister_request %p tid %lld\n", req, req->r_tid);
916 
917 	/* Never leave an unregistered request on an unsafe list! */
918 	list_del_init(&req->r_unsafe_item);
919 
920 	if (req->r_tid == mdsc->oldest_tid) {
921 		struct rb_node *p = rb_next(&req->r_node);
922 		mdsc->oldest_tid = 0;
923 		while (p) {
924 			struct ceph_mds_request *next_req =
925 				rb_entry(p, struct ceph_mds_request, r_node);
926 			if (next_req->r_op != CEPH_MDS_OP_SETFILELOCK) {
927 				mdsc->oldest_tid = next_req->r_tid;
928 				break;
929 			}
930 			p = rb_next(p);
931 		}
932 	}
933 
934 	erase_request(&mdsc->request_tree, req);
935 
936 	if (req->r_unsafe_dir) {
937 		struct ceph_inode_info *ci = ceph_inode(req->r_unsafe_dir);
938 		spin_lock(&ci->i_unsafe_lock);
939 		list_del_init(&req->r_unsafe_dir_item);
940 		spin_unlock(&ci->i_unsafe_lock);
941 	}
942 	if (req->r_target_inode &&
943 	    test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
944 		struct ceph_inode_info *ci = ceph_inode(req->r_target_inode);
945 		spin_lock(&ci->i_unsafe_lock);
946 		list_del_init(&req->r_unsafe_target_item);
947 		spin_unlock(&ci->i_unsafe_lock);
948 	}
949 
950 	if (req->r_unsafe_dir) {
951 		/* avoid calling iput_final() in mds dispatch threads */
952 		ceph_async_iput(req->r_unsafe_dir);
953 		req->r_unsafe_dir = NULL;
954 	}
955 
956 	complete_all(&req->r_safe_completion);
957 
958 	ceph_mdsc_put_request(req);
959 }
960 
961 /*
962  * Walk back up the dentry tree until we hit a dentry representing a
963  * non-snapshot inode. We do this using the rcu_read_lock (which must be held
964  * when calling this) to ensure that the objects won't disappear while we're
965  * working with them. Once we hit a candidate dentry, we attempt to take a
966  * reference to it, and return that as the result.
967  */
968 static struct inode *get_nonsnap_parent(struct dentry *dentry)
969 {
970 	struct inode *inode = NULL;
971 
972 	while (dentry && !IS_ROOT(dentry)) {
973 		inode = d_inode_rcu(dentry);
974 		if (!inode || ceph_snap(inode) == CEPH_NOSNAP)
975 			break;
976 		dentry = dentry->d_parent;
977 	}
978 	if (inode)
979 		inode = igrab(inode);
980 	return inode;
981 }
982 
983 /*
984  * Choose mds to send request to next.  If there is a hint set in the
985  * request (e.g., due to a prior forward hint from the mds), use that.
986  * Otherwise, consult frag tree and/or caps to identify the
987  * appropriate mds.  If all else fails, choose randomly.
988  *
989  * Called under mdsc->mutex.
990  */
991 static int __choose_mds(struct ceph_mds_client *mdsc,
992 			struct ceph_mds_request *req,
993 			bool *random)
994 {
995 	struct inode *inode;
996 	struct ceph_inode_info *ci;
997 	struct ceph_cap *cap;
998 	int mode = req->r_direct_mode;
999 	int mds = -1;
1000 	u32 hash = req->r_direct_hash;
1001 	bool is_hash = test_bit(CEPH_MDS_R_DIRECT_IS_HASH, &req->r_req_flags);
1002 
1003 	if (random)
1004 		*random = false;
1005 
1006 	/*
1007 	 * is there a specific mds we should try?  ignore hint if we have
1008 	 * no session and the mds is not up (active or recovering).
1009 	 */
1010 	if (req->r_resend_mds >= 0 &&
1011 	    (__have_session(mdsc, req->r_resend_mds) ||
1012 	     ceph_mdsmap_get_state(mdsc->mdsmap, req->r_resend_mds) > 0)) {
1013 		dout("%s using resend_mds mds%d\n", __func__,
1014 		     req->r_resend_mds);
1015 		return req->r_resend_mds;
1016 	}
1017 
1018 	if (mode == USE_RANDOM_MDS)
1019 		goto random;
1020 
1021 	inode = NULL;
1022 	if (req->r_inode) {
1023 		if (ceph_snap(req->r_inode) != CEPH_SNAPDIR) {
1024 			inode = req->r_inode;
1025 			ihold(inode);
1026 		} else {
1027 			/* req->r_dentry is non-null for LSSNAP request */
1028 			rcu_read_lock();
1029 			inode = get_nonsnap_parent(req->r_dentry);
1030 			rcu_read_unlock();
1031 			dout("%s using snapdir's parent %p\n", __func__, inode);
1032 		}
1033 	} else if (req->r_dentry) {
1034 		/* ignore race with rename; old or new d_parent is okay */
1035 		struct dentry *parent;
1036 		struct inode *dir;
1037 
1038 		rcu_read_lock();
1039 		parent = READ_ONCE(req->r_dentry->d_parent);
1040 		dir = req->r_parent ? : d_inode_rcu(parent);
1041 
1042 		if (!dir || dir->i_sb != mdsc->fsc->sb) {
1043 			/*  not this fs or parent went negative */
1044 			inode = d_inode(req->r_dentry);
1045 			if (inode)
1046 				ihold(inode);
1047 		} else if (ceph_snap(dir) != CEPH_NOSNAP) {
1048 			/* direct snapped/virtual snapdir requests
1049 			 * based on parent dir inode */
1050 			inode = get_nonsnap_parent(parent);
1051 			dout("%s using nonsnap parent %p\n", __func__, inode);
1052 		} else {
1053 			/* dentry target */
1054 			inode = d_inode(req->r_dentry);
1055 			if (!inode || mode == USE_AUTH_MDS) {
1056 				/* dir + name */
1057 				inode = igrab(dir);
1058 				hash = ceph_dentry_hash(dir, req->r_dentry);
1059 				is_hash = true;
1060 			} else {
1061 				ihold(inode);
1062 			}
1063 		}
1064 		rcu_read_unlock();
1065 	}
1066 
1067 	dout("%s %p is_hash=%d (0x%x) mode %d\n", __func__, inode, (int)is_hash,
1068 	     hash, mode);
1069 	if (!inode)
1070 		goto random;
1071 	ci = ceph_inode(inode);
1072 
1073 	if (is_hash && S_ISDIR(inode->i_mode)) {
1074 		struct ceph_inode_frag frag;
1075 		int found;
1076 
1077 		ceph_choose_frag(ci, hash, &frag, &found);
1078 		if (found) {
1079 			if (mode == USE_ANY_MDS && frag.ndist > 0) {
1080 				u8 r;
1081 
1082 				/* choose a random replica */
1083 				get_random_bytes(&r, 1);
1084 				r %= frag.ndist;
1085 				mds = frag.dist[r];
1086 				dout("%s %p %llx.%llx frag %u mds%d (%d/%d)\n",
1087 				     __func__, inode, ceph_vinop(inode),
1088 				     frag.frag, mds, (int)r, frag.ndist);
1089 				if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
1090 				    CEPH_MDS_STATE_ACTIVE &&
1091 				    !ceph_mdsmap_is_laggy(mdsc->mdsmap, mds))
1092 					goto out;
1093 			}
1094 
1095 			/* since this file/dir wasn't known to be
1096 			 * replicated, then we want to look for the
1097 			 * authoritative mds. */
1098 			if (frag.mds >= 0) {
1099 				/* choose auth mds */
1100 				mds = frag.mds;
1101 				dout("%s %p %llx.%llx frag %u mds%d (auth)\n",
1102 				     __func__, inode, ceph_vinop(inode),
1103 				     frag.frag, mds);
1104 				if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
1105 				    CEPH_MDS_STATE_ACTIVE) {
1106 					if (mode == USE_ANY_MDS &&
1107 					    !ceph_mdsmap_is_laggy(mdsc->mdsmap,
1108 								  mds))
1109 						goto out;
1110 				}
1111 			}
1112 			mode = USE_AUTH_MDS;
1113 		}
1114 	}
1115 
1116 	spin_lock(&ci->i_ceph_lock);
1117 	cap = NULL;
1118 	if (mode == USE_AUTH_MDS)
1119 		cap = ci->i_auth_cap;
1120 	if (!cap && !RB_EMPTY_ROOT(&ci->i_caps))
1121 		cap = rb_entry(rb_first(&ci->i_caps), struct ceph_cap, ci_node);
1122 	if (!cap) {
1123 		spin_unlock(&ci->i_ceph_lock);
1124 		ceph_async_iput(inode);
1125 		goto random;
1126 	}
1127 	mds = cap->session->s_mds;
1128 	dout("%s %p %llx.%llx mds%d (%scap %p)\n", __func__,
1129 	     inode, ceph_vinop(inode), mds,
1130 	     cap == ci->i_auth_cap ? "auth " : "", cap);
1131 	spin_unlock(&ci->i_ceph_lock);
1132 out:
1133 	/* avoid calling iput_final() while holding mdsc->mutex or
1134 	 * in mds dispatch threads */
1135 	ceph_async_iput(inode);
1136 	return mds;
1137 
1138 random:
1139 	if (random)
1140 		*random = true;
1141 
1142 	mds = ceph_mdsmap_get_random_mds(mdsc->mdsmap);
1143 	dout("%s chose random mds%d\n", __func__, mds);
1144 	return mds;
1145 }
1146 
1147 
1148 /*
1149  * session messages
1150  */
1151 static struct ceph_msg *create_session_msg(u32 op, u64 seq)
1152 {
1153 	struct ceph_msg *msg;
1154 	struct ceph_mds_session_head *h;
1155 
1156 	msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h), GFP_NOFS,
1157 			   false);
1158 	if (!msg) {
1159 		pr_err("create_session_msg ENOMEM creating msg\n");
1160 		return NULL;
1161 	}
1162 	h = msg->front.iov_base;
1163 	h->op = cpu_to_le32(op);
1164 	h->seq = cpu_to_le64(seq);
1165 
1166 	return msg;
1167 }
1168 
1169 static const unsigned char feature_bits[] = CEPHFS_FEATURES_CLIENT_SUPPORTED;
1170 #define FEATURE_BYTES(c) (DIV_ROUND_UP((size_t)feature_bits[c - 1] + 1, 64) * 8)
1171 static int encode_supported_features(void **p, void *end)
1172 {
1173 	static const size_t count = ARRAY_SIZE(feature_bits);
1174 
1175 	if (count > 0) {
1176 		size_t i;
1177 		size_t size = FEATURE_BYTES(count);
1178 
1179 		if (WARN_ON_ONCE(*p + 4 + size > end))
1180 			return -ERANGE;
1181 
1182 		ceph_encode_32(p, size);
1183 		memset(*p, 0, size);
1184 		for (i = 0; i < count; i++)
1185 			((unsigned char*)(*p))[i / 8] |= BIT(feature_bits[i] % 8);
1186 		*p += size;
1187 	} else {
1188 		if (WARN_ON_ONCE(*p + 4 > end))
1189 			return -ERANGE;
1190 
1191 		ceph_encode_32(p, 0);
1192 	}
1193 
1194 	return 0;
1195 }
1196 
1197 /*
1198  * session message, specialization for CEPH_SESSION_REQUEST_OPEN
1199  * to include additional client metadata fields.
1200  */
1201 static struct ceph_msg *create_session_open_msg(struct ceph_mds_client *mdsc, u64 seq)
1202 {
1203 	struct ceph_msg *msg;
1204 	struct ceph_mds_session_head *h;
1205 	int i = -1;
1206 	int extra_bytes = 0;
1207 	int metadata_key_count = 0;
1208 	struct ceph_options *opt = mdsc->fsc->client->options;
1209 	struct ceph_mount_options *fsopt = mdsc->fsc->mount_options;
1210 	size_t size, count;
1211 	void *p, *end;
1212 	int ret;
1213 
1214 	const char* metadata[][2] = {
1215 		{"hostname", mdsc->nodename},
1216 		{"kernel_version", init_utsname()->release},
1217 		{"entity_id", opt->name ? : ""},
1218 		{"root", fsopt->server_path ? : "/"},
1219 		{NULL, NULL}
1220 	};
1221 
1222 	/* Calculate serialized length of metadata */
1223 	extra_bytes = 4;  /* map length */
1224 	for (i = 0; metadata[i][0]; ++i) {
1225 		extra_bytes += 8 + strlen(metadata[i][0]) +
1226 			strlen(metadata[i][1]);
1227 		metadata_key_count++;
1228 	}
1229 
1230 	/* supported feature */
1231 	size = 0;
1232 	count = ARRAY_SIZE(feature_bits);
1233 	if (count > 0)
1234 		size = FEATURE_BYTES(count);
1235 	extra_bytes += 4 + size;
1236 
1237 	/* Allocate the message */
1238 	msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h) + extra_bytes,
1239 			   GFP_NOFS, false);
1240 	if (!msg) {
1241 		pr_err("create_session_msg ENOMEM creating msg\n");
1242 		return ERR_PTR(-ENOMEM);
1243 	}
1244 	p = msg->front.iov_base;
1245 	end = p + msg->front.iov_len;
1246 
1247 	h = p;
1248 	h->op = cpu_to_le32(CEPH_SESSION_REQUEST_OPEN);
1249 	h->seq = cpu_to_le64(seq);
1250 
1251 	/*
1252 	 * Serialize client metadata into waiting buffer space, using
1253 	 * the format that userspace expects for map<string, string>
1254 	 *
1255 	 * ClientSession messages with metadata are v3
1256 	 */
1257 	msg->hdr.version = cpu_to_le16(3);
1258 	msg->hdr.compat_version = cpu_to_le16(1);
1259 
1260 	/* The write pointer, following the session_head structure */
1261 	p += sizeof(*h);
1262 
1263 	/* Number of entries in the map */
1264 	ceph_encode_32(&p, metadata_key_count);
1265 
1266 	/* Two length-prefixed strings for each entry in the map */
1267 	for (i = 0; metadata[i][0]; ++i) {
1268 		size_t const key_len = strlen(metadata[i][0]);
1269 		size_t const val_len = strlen(metadata[i][1]);
1270 
1271 		ceph_encode_32(&p, key_len);
1272 		memcpy(p, metadata[i][0], key_len);
1273 		p += key_len;
1274 		ceph_encode_32(&p, val_len);
1275 		memcpy(p, metadata[i][1], val_len);
1276 		p += val_len;
1277 	}
1278 
1279 	ret = encode_supported_features(&p, end);
1280 	if (ret) {
1281 		pr_err("encode_supported_features failed!\n");
1282 		ceph_msg_put(msg);
1283 		return ERR_PTR(ret);
1284 	}
1285 
1286 	msg->front.iov_len = p - msg->front.iov_base;
1287 	msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
1288 
1289 	return msg;
1290 }
1291 
1292 /*
1293  * send session open request.
1294  *
1295  * called under mdsc->mutex
1296  */
1297 static int __open_session(struct ceph_mds_client *mdsc,
1298 			  struct ceph_mds_session *session)
1299 {
1300 	struct ceph_msg *msg;
1301 	int mstate;
1302 	int mds = session->s_mds;
1303 
1304 	/* wait for mds to go active? */
1305 	mstate = ceph_mdsmap_get_state(mdsc->mdsmap, mds);
1306 	dout("open_session to mds%d (%s)\n", mds,
1307 	     ceph_mds_state_name(mstate));
1308 	session->s_state = CEPH_MDS_SESSION_OPENING;
1309 	session->s_renew_requested = jiffies;
1310 
1311 	/* send connect message */
1312 	msg = create_session_open_msg(mdsc, session->s_seq);
1313 	if (IS_ERR(msg))
1314 		return PTR_ERR(msg);
1315 	ceph_con_send(&session->s_con, msg);
1316 	return 0;
1317 }
1318 
1319 /*
1320  * open sessions for any export targets for the given mds
1321  *
1322  * called under mdsc->mutex
1323  */
1324 static struct ceph_mds_session *
1325 __open_export_target_session(struct ceph_mds_client *mdsc, int target)
1326 {
1327 	struct ceph_mds_session *session;
1328 	int ret;
1329 
1330 	session = __ceph_lookup_mds_session(mdsc, target);
1331 	if (!session) {
1332 		session = register_session(mdsc, target);
1333 		if (IS_ERR(session))
1334 			return session;
1335 	}
1336 	if (session->s_state == CEPH_MDS_SESSION_NEW ||
1337 	    session->s_state == CEPH_MDS_SESSION_CLOSING) {
1338 		ret = __open_session(mdsc, session);
1339 		if (ret)
1340 			return ERR_PTR(ret);
1341 	}
1342 
1343 	return session;
1344 }
1345 
1346 struct ceph_mds_session *
1347 ceph_mdsc_open_export_target_session(struct ceph_mds_client *mdsc, int target)
1348 {
1349 	struct ceph_mds_session *session;
1350 
1351 	dout("open_export_target_session to mds%d\n", target);
1352 
1353 	mutex_lock(&mdsc->mutex);
1354 	session = __open_export_target_session(mdsc, target);
1355 	mutex_unlock(&mdsc->mutex);
1356 
1357 	return session;
1358 }
1359 
1360 static void __open_export_target_sessions(struct ceph_mds_client *mdsc,
1361 					  struct ceph_mds_session *session)
1362 {
1363 	struct ceph_mds_info *mi;
1364 	struct ceph_mds_session *ts;
1365 	int i, mds = session->s_mds;
1366 
1367 	if (mds >= mdsc->mdsmap->possible_max_rank)
1368 		return;
1369 
1370 	mi = &mdsc->mdsmap->m_info[mds];
1371 	dout("open_export_target_sessions for mds%d (%d targets)\n",
1372 	     session->s_mds, mi->num_export_targets);
1373 
1374 	for (i = 0; i < mi->num_export_targets; i++) {
1375 		ts = __open_export_target_session(mdsc, mi->export_targets[i]);
1376 		if (!IS_ERR(ts))
1377 			ceph_put_mds_session(ts);
1378 	}
1379 }
1380 
1381 void ceph_mdsc_open_export_target_sessions(struct ceph_mds_client *mdsc,
1382 					   struct ceph_mds_session *session)
1383 {
1384 	mutex_lock(&mdsc->mutex);
1385 	__open_export_target_sessions(mdsc, session);
1386 	mutex_unlock(&mdsc->mutex);
1387 }
1388 
1389 /*
1390  * session caps
1391  */
1392 
1393 static void detach_cap_releases(struct ceph_mds_session *session,
1394 				struct list_head *target)
1395 {
1396 	lockdep_assert_held(&session->s_cap_lock);
1397 
1398 	list_splice_init(&session->s_cap_releases, target);
1399 	session->s_num_cap_releases = 0;
1400 	dout("dispose_cap_releases mds%d\n", session->s_mds);
1401 }
1402 
1403 static void dispose_cap_releases(struct ceph_mds_client *mdsc,
1404 				 struct list_head *dispose)
1405 {
1406 	while (!list_empty(dispose)) {
1407 		struct ceph_cap *cap;
1408 		/* zero out the in-progress message */
1409 		cap = list_first_entry(dispose, struct ceph_cap, session_caps);
1410 		list_del(&cap->session_caps);
1411 		ceph_put_cap(mdsc, cap);
1412 	}
1413 }
1414 
1415 static void cleanup_session_requests(struct ceph_mds_client *mdsc,
1416 				     struct ceph_mds_session *session)
1417 {
1418 	struct ceph_mds_request *req;
1419 	struct rb_node *p;
1420 	struct ceph_inode_info *ci;
1421 
1422 	dout("cleanup_session_requests mds%d\n", session->s_mds);
1423 	mutex_lock(&mdsc->mutex);
1424 	while (!list_empty(&session->s_unsafe)) {
1425 		req = list_first_entry(&session->s_unsafe,
1426 				       struct ceph_mds_request, r_unsafe_item);
1427 		pr_warn_ratelimited(" dropping unsafe request %llu\n",
1428 				    req->r_tid);
1429 		if (req->r_target_inode) {
1430 			/* dropping unsafe change of inode's attributes */
1431 			ci = ceph_inode(req->r_target_inode);
1432 			errseq_set(&ci->i_meta_err, -EIO);
1433 		}
1434 		if (req->r_unsafe_dir) {
1435 			/* dropping unsafe directory operation */
1436 			ci = ceph_inode(req->r_unsafe_dir);
1437 			errseq_set(&ci->i_meta_err, -EIO);
1438 		}
1439 		__unregister_request(mdsc, req);
1440 	}
1441 	/* zero r_attempts, so kick_requests() will re-send requests */
1442 	p = rb_first(&mdsc->request_tree);
1443 	while (p) {
1444 		req = rb_entry(p, struct ceph_mds_request, r_node);
1445 		p = rb_next(p);
1446 		if (req->r_session &&
1447 		    req->r_session->s_mds == session->s_mds)
1448 			req->r_attempts = 0;
1449 	}
1450 	mutex_unlock(&mdsc->mutex);
1451 }
1452 
1453 /*
1454  * Helper to safely iterate over all caps associated with a session, with
1455  * special care taken to handle a racing __ceph_remove_cap().
1456  *
1457  * Caller must hold session s_mutex.
1458  */
1459 int ceph_iterate_session_caps(struct ceph_mds_session *session,
1460 			      int (*cb)(struct inode *, struct ceph_cap *,
1461 					void *), void *arg)
1462 {
1463 	struct list_head *p;
1464 	struct ceph_cap *cap;
1465 	struct inode *inode, *last_inode = NULL;
1466 	struct ceph_cap *old_cap = NULL;
1467 	int ret;
1468 
1469 	dout("iterate_session_caps %p mds%d\n", session, session->s_mds);
1470 	spin_lock(&session->s_cap_lock);
1471 	p = session->s_caps.next;
1472 	while (p != &session->s_caps) {
1473 		cap = list_entry(p, struct ceph_cap, session_caps);
1474 		inode = igrab(&cap->ci->vfs_inode);
1475 		if (!inode) {
1476 			p = p->next;
1477 			continue;
1478 		}
1479 		session->s_cap_iterator = cap;
1480 		spin_unlock(&session->s_cap_lock);
1481 
1482 		if (last_inode) {
1483 			/* avoid calling iput_final() while holding
1484 			 * s_mutex or in mds dispatch threads */
1485 			ceph_async_iput(last_inode);
1486 			last_inode = NULL;
1487 		}
1488 		if (old_cap) {
1489 			ceph_put_cap(session->s_mdsc, old_cap);
1490 			old_cap = NULL;
1491 		}
1492 
1493 		ret = cb(inode, cap, arg);
1494 		last_inode = inode;
1495 
1496 		spin_lock(&session->s_cap_lock);
1497 		p = p->next;
1498 		if (!cap->ci) {
1499 			dout("iterate_session_caps  finishing cap %p removal\n",
1500 			     cap);
1501 			BUG_ON(cap->session != session);
1502 			cap->session = NULL;
1503 			list_del_init(&cap->session_caps);
1504 			session->s_nr_caps--;
1505 			atomic64_dec(&session->s_mdsc->metric.total_caps);
1506 			if (cap->queue_release)
1507 				__ceph_queue_cap_release(session, cap);
1508 			else
1509 				old_cap = cap;  /* put_cap it w/o locks held */
1510 		}
1511 		if (ret < 0)
1512 			goto out;
1513 	}
1514 	ret = 0;
1515 out:
1516 	session->s_cap_iterator = NULL;
1517 	spin_unlock(&session->s_cap_lock);
1518 
1519 	ceph_async_iput(last_inode);
1520 	if (old_cap)
1521 		ceph_put_cap(session->s_mdsc, old_cap);
1522 
1523 	return ret;
1524 }
1525 
1526 static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
1527 				  void *arg)
1528 {
1529 	struct ceph_fs_client *fsc = (struct ceph_fs_client *)arg;
1530 	struct ceph_inode_info *ci = ceph_inode(inode);
1531 	LIST_HEAD(to_remove);
1532 	bool dirty_dropped = false;
1533 	bool invalidate = false;
1534 
1535 	dout("removing cap %p, ci is %p, inode is %p\n",
1536 	     cap, ci, &ci->vfs_inode);
1537 	spin_lock(&ci->i_ceph_lock);
1538 	__ceph_remove_cap(cap, false);
1539 	if (!ci->i_auth_cap) {
1540 		struct ceph_cap_flush *cf;
1541 		struct ceph_mds_client *mdsc = fsc->mdsc;
1542 
1543 		if (READ_ONCE(fsc->mount_state) == CEPH_MOUNT_SHUTDOWN) {
1544 			if (inode->i_data.nrpages > 0)
1545 				invalidate = true;
1546 			if (ci->i_wrbuffer_ref > 0)
1547 				mapping_set_error(&inode->i_data, -EIO);
1548 		}
1549 
1550 		while (!list_empty(&ci->i_cap_flush_list)) {
1551 			cf = list_first_entry(&ci->i_cap_flush_list,
1552 					      struct ceph_cap_flush, i_list);
1553 			list_move(&cf->i_list, &to_remove);
1554 		}
1555 
1556 		spin_lock(&mdsc->cap_dirty_lock);
1557 
1558 		list_for_each_entry(cf, &to_remove, i_list)
1559 			list_del(&cf->g_list);
1560 
1561 		if (!list_empty(&ci->i_dirty_item)) {
1562 			pr_warn_ratelimited(
1563 				" dropping dirty %s state for %p %lld\n",
1564 				ceph_cap_string(ci->i_dirty_caps),
1565 				inode, ceph_ino(inode));
1566 			ci->i_dirty_caps = 0;
1567 			list_del_init(&ci->i_dirty_item);
1568 			dirty_dropped = true;
1569 		}
1570 		if (!list_empty(&ci->i_flushing_item)) {
1571 			pr_warn_ratelimited(
1572 				" dropping dirty+flushing %s state for %p %lld\n",
1573 				ceph_cap_string(ci->i_flushing_caps),
1574 				inode, ceph_ino(inode));
1575 			ci->i_flushing_caps = 0;
1576 			list_del_init(&ci->i_flushing_item);
1577 			mdsc->num_cap_flushing--;
1578 			dirty_dropped = true;
1579 		}
1580 		spin_unlock(&mdsc->cap_dirty_lock);
1581 
1582 		if (dirty_dropped) {
1583 			errseq_set(&ci->i_meta_err, -EIO);
1584 
1585 			if (ci->i_wrbuffer_ref_head == 0 &&
1586 			    ci->i_wr_ref == 0 &&
1587 			    ci->i_dirty_caps == 0 &&
1588 			    ci->i_flushing_caps == 0) {
1589 				ceph_put_snap_context(ci->i_head_snapc);
1590 				ci->i_head_snapc = NULL;
1591 			}
1592 		}
1593 
1594 		if (atomic_read(&ci->i_filelock_ref) > 0) {
1595 			/* make further file lock syscall return -EIO */
1596 			ci->i_ceph_flags |= CEPH_I_ERROR_FILELOCK;
1597 			pr_warn_ratelimited(" dropping file locks for %p %lld\n",
1598 					    inode, ceph_ino(inode));
1599 		}
1600 
1601 		if (!ci->i_dirty_caps && ci->i_prealloc_cap_flush) {
1602 			list_add(&ci->i_prealloc_cap_flush->i_list, &to_remove);
1603 			ci->i_prealloc_cap_flush = NULL;
1604 		}
1605 	}
1606 	spin_unlock(&ci->i_ceph_lock);
1607 	while (!list_empty(&to_remove)) {
1608 		struct ceph_cap_flush *cf;
1609 		cf = list_first_entry(&to_remove,
1610 				      struct ceph_cap_flush, i_list);
1611 		list_del(&cf->i_list);
1612 		ceph_free_cap_flush(cf);
1613 	}
1614 
1615 	wake_up_all(&ci->i_cap_wq);
1616 	if (invalidate)
1617 		ceph_queue_invalidate(inode);
1618 	if (dirty_dropped)
1619 		iput(inode);
1620 	return 0;
1621 }
1622 
1623 /*
1624  * caller must hold session s_mutex
1625  */
1626 static void remove_session_caps(struct ceph_mds_session *session)
1627 {
1628 	struct ceph_fs_client *fsc = session->s_mdsc->fsc;
1629 	struct super_block *sb = fsc->sb;
1630 	LIST_HEAD(dispose);
1631 
1632 	dout("remove_session_caps on %p\n", session);
1633 	ceph_iterate_session_caps(session, remove_session_caps_cb, fsc);
1634 
1635 	wake_up_all(&fsc->mdsc->cap_flushing_wq);
1636 
1637 	spin_lock(&session->s_cap_lock);
1638 	if (session->s_nr_caps > 0) {
1639 		struct inode *inode;
1640 		struct ceph_cap *cap, *prev = NULL;
1641 		struct ceph_vino vino;
1642 		/*
1643 		 * iterate_session_caps() skips inodes that are being
1644 		 * deleted, we need to wait until deletions are complete.
1645 		 * __wait_on_freeing_inode() is designed for the job,
1646 		 * but it is not exported, so use lookup inode function
1647 		 * to access it.
1648 		 */
1649 		while (!list_empty(&session->s_caps)) {
1650 			cap = list_entry(session->s_caps.next,
1651 					 struct ceph_cap, session_caps);
1652 			if (cap == prev)
1653 				break;
1654 			prev = cap;
1655 			vino = cap->ci->i_vino;
1656 			spin_unlock(&session->s_cap_lock);
1657 
1658 			inode = ceph_find_inode(sb, vino);
1659 			 /* avoid calling iput_final() while holding s_mutex */
1660 			ceph_async_iput(inode);
1661 
1662 			spin_lock(&session->s_cap_lock);
1663 		}
1664 	}
1665 
1666 	// drop cap expires and unlock s_cap_lock
1667 	detach_cap_releases(session, &dispose);
1668 
1669 	BUG_ON(session->s_nr_caps > 0);
1670 	BUG_ON(!list_empty(&session->s_cap_flushing));
1671 	spin_unlock(&session->s_cap_lock);
1672 	dispose_cap_releases(session->s_mdsc, &dispose);
1673 }
1674 
1675 enum {
1676 	RECONNECT,
1677 	RENEWCAPS,
1678 	FORCE_RO,
1679 };
1680 
1681 /*
1682  * wake up any threads waiting on this session's caps.  if the cap is
1683  * old (didn't get renewed on the client reconnect), remove it now.
1684  *
1685  * caller must hold s_mutex.
1686  */
1687 static int wake_up_session_cb(struct inode *inode, struct ceph_cap *cap,
1688 			      void *arg)
1689 {
1690 	struct ceph_inode_info *ci = ceph_inode(inode);
1691 	unsigned long ev = (unsigned long)arg;
1692 
1693 	if (ev == RECONNECT) {
1694 		spin_lock(&ci->i_ceph_lock);
1695 		ci->i_wanted_max_size = 0;
1696 		ci->i_requested_max_size = 0;
1697 		spin_unlock(&ci->i_ceph_lock);
1698 	} else if (ev == RENEWCAPS) {
1699 		if (cap->cap_gen < cap->session->s_cap_gen) {
1700 			/* mds did not re-issue stale cap */
1701 			spin_lock(&ci->i_ceph_lock);
1702 			cap->issued = cap->implemented = CEPH_CAP_PIN;
1703 			spin_unlock(&ci->i_ceph_lock);
1704 		}
1705 	} else if (ev == FORCE_RO) {
1706 	}
1707 	wake_up_all(&ci->i_cap_wq);
1708 	return 0;
1709 }
1710 
1711 static void wake_up_session_caps(struct ceph_mds_session *session, int ev)
1712 {
1713 	dout("wake_up_session_caps %p mds%d\n", session, session->s_mds);
1714 	ceph_iterate_session_caps(session, wake_up_session_cb,
1715 				  (void *)(unsigned long)ev);
1716 }
1717 
1718 /*
1719  * Send periodic message to MDS renewing all currently held caps.  The
1720  * ack will reset the expiration for all caps from this session.
1721  *
1722  * caller holds s_mutex
1723  */
1724 static int send_renew_caps(struct ceph_mds_client *mdsc,
1725 			   struct ceph_mds_session *session)
1726 {
1727 	struct ceph_msg *msg;
1728 	int state;
1729 
1730 	if (time_after_eq(jiffies, session->s_cap_ttl) &&
1731 	    time_after_eq(session->s_cap_ttl, session->s_renew_requested))
1732 		pr_info("mds%d caps stale\n", session->s_mds);
1733 	session->s_renew_requested = jiffies;
1734 
1735 	/* do not try to renew caps until a recovering mds has reconnected
1736 	 * with its clients. */
1737 	state = ceph_mdsmap_get_state(mdsc->mdsmap, session->s_mds);
1738 	if (state < CEPH_MDS_STATE_RECONNECT) {
1739 		dout("send_renew_caps ignoring mds%d (%s)\n",
1740 		     session->s_mds, ceph_mds_state_name(state));
1741 		return 0;
1742 	}
1743 
1744 	dout("send_renew_caps to mds%d (%s)\n", session->s_mds,
1745 		ceph_mds_state_name(state));
1746 	msg = create_session_msg(CEPH_SESSION_REQUEST_RENEWCAPS,
1747 				 ++session->s_renew_seq);
1748 	if (!msg)
1749 		return -ENOMEM;
1750 	ceph_con_send(&session->s_con, msg);
1751 	return 0;
1752 }
1753 
1754 static int send_flushmsg_ack(struct ceph_mds_client *mdsc,
1755 			     struct ceph_mds_session *session, u64 seq)
1756 {
1757 	struct ceph_msg *msg;
1758 
1759 	dout("send_flushmsg_ack to mds%d (%s)s seq %lld\n",
1760 	     session->s_mds, ceph_session_state_name(session->s_state), seq);
1761 	msg = create_session_msg(CEPH_SESSION_FLUSHMSG_ACK, seq);
1762 	if (!msg)
1763 		return -ENOMEM;
1764 	ceph_con_send(&session->s_con, msg);
1765 	return 0;
1766 }
1767 
1768 
1769 /*
1770  * Note new cap ttl, and any transition from stale -> not stale (fresh?).
1771  *
1772  * Called under session->s_mutex
1773  */
1774 static void renewed_caps(struct ceph_mds_client *mdsc,
1775 			 struct ceph_mds_session *session, int is_renew)
1776 {
1777 	int was_stale;
1778 	int wake = 0;
1779 
1780 	spin_lock(&session->s_cap_lock);
1781 	was_stale = is_renew && time_after_eq(jiffies, session->s_cap_ttl);
1782 
1783 	session->s_cap_ttl = session->s_renew_requested +
1784 		mdsc->mdsmap->m_session_timeout*HZ;
1785 
1786 	if (was_stale) {
1787 		if (time_before(jiffies, session->s_cap_ttl)) {
1788 			pr_info("mds%d caps renewed\n", session->s_mds);
1789 			wake = 1;
1790 		} else {
1791 			pr_info("mds%d caps still stale\n", session->s_mds);
1792 		}
1793 	}
1794 	dout("renewed_caps mds%d ttl now %lu, was %s, now %s\n",
1795 	     session->s_mds, session->s_cap_ttl, was_stale ? "stale" : "fresh",
1796 	     time_before(jiffies, session->s_cap_ttl) ? "stale" : "fresh");
1797 	spin_unlock(&session->s_cap_lock);
1798 
1799 	if (wake)
1800 		wake_up_session_caps(session, RENEWCAPS);
1801 }
1802 
1803 /*
1804  * send a session close request
1805  */
1806 static int request_close_session(struct ceph_mds_session *session)
1807 {
1808 	struct ceph_msg *msg;
1809 
1810 	dout("request_close_session mds%d state %s seq %lld\n",
1811 	     session->s_mds, ceph_session_state_name(session->s_state),
1812 	     session->s_seq);
1813 	msg = create_session_msg(CEPH_SESSION_REQUEST_CLOSE, session->s_seq);
1814 	if (!msg)
1815 		return -ENOMEM;
1816 	ceph_con_send(&session->s_con, msg);
1817 	return 1;
1818 }
1819 
1820 /*
1821  * Called with s_mutex held.
1822  */
1823 static int __close_session(struct ceph_mds_client *mdsc,
1824 			 struct ceph_mds_session *session)
1825 {
1826 	if (session->s_state >= CEPH_MDS_SESSION_CLOSING)
1827 		return 0;
1828 	session->s_state = CEPH_MDS_SESSION_CLOSING;
1829 	return request_close_session(session);
1830 }
1831 
1832 static bool drop_negative_children(struct dentry *dentry)
1833 {
1834 	struct dentry *child;
1835 	bool all_negative = true;
1836 
1837 	if (!d_is_dir(dentry))
1838 		goto out;
1839 
1840 	spin_lock(&dentry->d_lock);
1841 	list_for_each_entry(child, &dentry->d_subdirs, d_child) {
1842 		if (d_really_is_positive(child)) {
1843 			all_negative = false;
1844 			break;
1845 		}
1846 	}
1847 	spin_unlock(&dentry->d_lock);
1848 
1849 	if (all_negative)
1850 		shrink_dcache_parent(dentry);
1851 out:
1852 	return all_negative;
1853 }
1854 
1855 /*
1856  * Trim old(er) caps.
1857  *
1858  * Because we can't cache an inode without one or more caps, we do
1859  * this indirectly: if a cap is unused, we prune its aliases, at which
1860  * point the inode will hopefully get dropped to.
1861  *
1862  * Yes, this is a bit sloppy.  Our only real goal here is to respond to
1863  * memory pressure from the MDS, though, so it needn't be perfect.
1864  */
1865 static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
1866 {
1867 	int *remaining = arg;
1868 	struct ceph_inode_info *ci = ceph_inode(inode);
1869 	int used, wanted, oissued, mine;
1870 
1871 	if (*remaining <= 0)
1872 		return -1;
1873 
1874 	spin_lock(&ci->i_ceph_lock);
1875 	mine = cap->issued | cap->implemented;
1876 	used = __ceph_caps_used(ci);
1877 	wanted = __ceph_caps_file_wanted(ci);
1878 	oissued = __ceph_caps_issued_other(ci, cap);
1879 
1880 	dout("trim_caps_cb %p cap %p mine %s oissued %s used %s wanted %s\n",
1881 	     inode, cap, ceph_cap_string(mine), ceph_cap_string(oissued),
1882 	     ceph_cap_string(used), ceph_cap_string(wanted));
1883 	if (cap == ci->i_auth_cap) {
1884 		if (ci->i_dirty_caps || ci->i_flushing_caps ||
1885 		    !list_empty(&ci->i_cap_snaps))
1886 			goto out;
1887 		if ((used | wanted) & CEPH_CAP_ANY_WR)
1888 			goto out;
1889 		/* Note: it's possible that i_filelock_ref becomes non-zero
1890 		 * after dropping auth caps. It doesn't hurt because reply
1891 		 * of lock mds request will re-add auth caps. */
1892 		if (atomic_read(&ci->i_filelock_ref) > 0)
1893 			goto out;
1894 	}
1895 	/* The inode has cached pages, but it's no longer used.
1896 	 * we can safely drop it */
1897 	if (S_ISREG(inode->i_mode) &&
1898 	    wanted == 0 && used == CEPH_CAP_FILE_CACHE &&
1899 	    !(oissued & CEPH_CAP_FILE_CACHE)) {
1900 	  used = 0;
1901 	  oissued = 0;
1902 	}
1903 	if ((used | wanted) & ~oissued & mine)
1904 		goto out;   /* we need these caps */
1905 
1906 	if (oissued) {
1907 		/* we aren't the only cap.. just remove us */
1908 		__ceph_remove_cap(cap, true);
1909 		(*remaining)--;
1910 	} else {
1911 		struct dentry *dentry;
1912 		/* try dropping referring dentries */
1913 		spin_unlock(&ci->i_ceph_lock);
1914 		dentry = d_find_any_alias(inode);
1915 		if (dentry && drop_negative_children(dentry)) {
1916 			int count;
1917 			dput(dentry);
1918 			d_prune_aliases(inode);
1919 			count = atomic_read(&inode->i_count);
1920 			if (count == 1)
1921 				(*remaining)--;
1922 			dout("trim_caps_cb %p cap %p pruned, count now %d\n",
1923 			     inode, cap, count);
1924 		} else {
1925 			dput(dentry);
1926 		}
1927 		return 0;
1928 	}
1929 
1930 out:
1931 	spin_unlock(&ci->i_ceph_lock);
1932 	return 0;
1933 }
1934 
1935 /*
1936  * Trim session cap count down to some max number.
1937  */
1938 int ceph_trim_caps(struct ceph_mds_client *mdsc,
1939 		   struct ceph_mds_session *session,
1940 		   int max_caps)
1941 {
1942 	int trim_caps = session->s_nr_caps - max_caps;
1943 
1944 	dout("trim_caps mds%d start: %d / %d, trim %d\n",
1945 	     session->s_mds, session->s_nr_caps, max_caps, trim_caps);
1946 	if (trim_caps > 0) {
1947 		int remaining = trim_caps;
1948 
1949 		ceph_iterate_session_caps(session, trim_caps_cb, &remaining);
1950 		dout("trim_caps mds%d done: %d / %d, trimmed %d\n",
1951 		     session->s_mds, session->s_nr_caps, max_caps,
1952 			trim_caps - remaining);
1953 	}
1954 
1955 	ceph_flush_cap_releases(mdsc, session);
1956 	return 0;
1957 }
1958 
1959 static int check_caps_flush(struct ceph_mds_client *mdsc,
1960 			    u64 want_flush_tid)
1961 {
1962 	int ret = 1;
1963 
1964 	spin_lock(&mdsc->cap_dirty_lock);
1965 	if (!list_empty(&mdsc->cap_flush_list)) {
1966 		struct ceph_cap_flush *cf =
1967 			list_first_entry(&mdsc->cap_flush_list,
1968 					 struct ceph_cap_flush, g_list);
1969 		if (cf->tid <= want_flush_tid) {
1970 			dout("check_caps_flush still flushing tid "
1971 			     "%llu <= %llu\n", cf->tid, want_flush_tid);
1972 			ret = 0;
1973 		}
1974 	}
1975 	spin_unlock(&mdsc->cap_dirty_lock);
1976 	return ret;
1977 }
1978 
1979 /*
1980  * flush all dirty inode data to disk.
1981  *
1982  * returns true if we've flushed through want_flush_tid
1983  */
1984 static void wait_caps_flush(struct ceph_mds_client *mdsc,
1985 			    u64 want_flush_tid)
1986 {
1987 	dout("check_caps_flush want %llu\n", want_flush_tid);
1988 
1989 	wait_event(mdsc->cap_flushing_wq,
1990 		   check_caps_flush(mdsc, want_flush_tid));
1991 
1992 	dout("check_caps_flush ok, flushed thru %llu\n", want_flush_tid);
1993 }
1994 
1995 /*
1996  * called under s_mutex
1997  */
1998 static void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
1999 				   struct ceph_mds_session *session)
2000 {
2001 	struct ceph_msg *msg = NULL;
2002 	struct ceph_mds_cap_release *head;
2003 	struct ceph_mds_cap_item *item;
2004 	struct ceph_osd_client *osdc = &mdsc->fsc->client->osdc;
2005 	struct ceph_cap *cap;
2006 	LIST_HEAD(tmp_list);
2007 	int num_cap_releases;
2008 	__le32	barrier, *cap_barrier;
2009 
2010 	down_read(&osdc->lock);
2011 	barrier = cpu_to_le32(osdc->epoch_barrier);
2012 	up_read(&osdc->lock);
2013 
2014 	spin_lock(&session->s_cap_lock);
2015 again:
2016 	list_splice_init(&session->s_cap_releases, &tmp_list);
2017 	num_cap_releases = session->s_num_cap_releases;
2018 	session->s_num_cap_releases = 0;
2019 	spin_unlock(&session->s_cap_lock);
2020 
2021 	while (!list_empty(&tmp_list)) {
2022 		if (!msg) {
2023 			msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPRELEASE,
2024 					PAGE_SIZE, GFP_NOFS, false);
2025 			if (!msg)
2026 				goto out_err;
2027 			head = msg->front.iov_base;
2028 			head->num = cpu_to_le32(0);
2029 			msg->front.iov_len = sizeof(*head);
2030 
2031 			msg->hdr.version = cpu_to_le16(2);
2032 			msg->hdr.compat_version = cpu_to_le16(1);
2033 		}
2034 
2035 		cap = list_first_entry(&tmp_list, struct ceph_cap,
2036 					session_caps);
2037 		list_del(&cap->session_caps);
2038 		num_cap_releases--;
2039 
2040 		head = msg->front.iov_base;
2041 		put_unaligned_le32(get_unaligned_le32(&head->num) + 1,
2042 				   &head->num);
2043 		item = msg->front.iov_base + msg->front.iov_len;
2044 		item->ino = cpu_to_le64(cap->cap_ino);
2045 		item->cap_id = cpu_to_le64(cap->cap_id);
2046 		item->migrate_seq = cpu_to_le32(cap->mseq);
2047 		item->seq = cpu_to_le32(cap->issue_seq);
2048 		msg->front.iov_len += sizeof(*item);
2049 
2050 		ceph_put_cap(mdsc, cap);
2051 
2052 		if (le32_to_cpu(head->num) == CEPH_CAPS_PER_RELEASE) {
2053 			// Append cap_barrier field
2054 			cap_barrier = msg->front.iov_base + msg->front.iov_len;
2055 			*cap_barrier = barrier;
2056 			msg->front.iov_len += sizeof(*cap_barrier);
2057 
2058 			msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
2059 			dout("send_cap_releases mds%d %p\n", session->s_mds, msg);
2060 			ceph_con_send(&session->s_con, msg);
2061 			msg = NULL;
2062 		}
2063 	}
2064 
2065 	BUG_ON(num_cap_releases != 0);
2066 
2067 	spin_lock(&session->s_cap_lock);
2068 	if (!list_empty(&session->s_cap_releases))
2069 		goto again;
2070 	spin_unlock(&session->s_cap_lock);
2071 
2072 	if (msg) {
2073 		// Append cap_barrier field
2074 		cap_barrier = msg->front.iov_base + msg->front.iov_len;
2075 		*cap_barrier = barrier;
2076 		msg->front.iov_len += sizeof(*cap_barrier);
2077 
2078 		msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
2079 		dout("send_cap_releases mds%d %p\n", session->s_mds, msg);
2080 		ceph_con_send(&session->s_con, msg);
2081 	}
2082 	return;
2083 out_err:
2084 	pr_err("send_cap_releases mds%d, failed to allocate message\n",
2085 		session->s_mds);
2086 	spin_lock(&session->s_cap_lock);
2087 	list_splice(&tmp_list, &session->s_cap_releases);
2088 	session->s_num_cap_releases += num_cap_releases;
2089 	spin_unlock(&session->s_cap_lock);
2090 }
2091 
2092 static void ceph_cap_release_work(struct work_struct *work)
2093 {
2094 	struct ceph_mds_session *session =
2095 		container_of(work, struct ceph_mds_session, s_cap_release_work);
2096 
2097 	mutex_lock(&session->s_mutex);
2098 	if (session->s_state == CEPH_MDS_SESSION_OPEN ||
2099 	    session->s_state == CEPH_MDS_SESSION_HUNG)
2100 		ceph_send_cap_releases(session->s_mdsc, session);
2101 	mutex_unlock(&session->s_mutex);
2102 	ceph_put_mds_session(session);
2103 }
2104 
2105 void ceph_flush_cap_releases(struct ceph_mds_client *mdsc,
2106 		             struct ceph_mds_session *session)
2107 {
2108 	if (mdsc->stopping)
2109 		return;
2110 
2111 	ceph_get_mds_session(session);
2112 	if (queue_work(mdsc->fsc->cap_wq,
2113 		       &session->s_cap_release_work)) {
2114 		dout("cap release work queued\n");
2115 	} else {
2116 		ceph_put_mds_session(session);
2117 		dout("failed to queue cap release work\n");
2118 	}
2119 }
2120 
2121 /*
2122  * caller holds session->s_cap_lock
2123  */
2124 void __ceph_queue_cap_release(struct ceph_mds_session *session,
2125 			      struct ceph_cap *cap)
2126 {
2127 	list_add_tail(&cap->session_caps, &session->s_cap_releases);
2128 	session->s_num_cap_releases++;
2129 
2130 	if (!(session->s_num_cap_releases % CEPH_CAPS_PER_RELEASE))
2131 		ceph_flush_cap_releases(session->s_mdsc, session);
2132 }
2133 
2134 static void ceph_cap_reclaim_work(struct work_struct *work)
2135 {
2136 	struct ceph_mds_client *mdsc =
2137 		container_of(work, struct ceph_mds_client, cap_reclaim_work);
2138 	int ret = ceph_trim_dentries(mdsc);
2139 	if (ret == -EAGAIN)
2140 		ceph_queue_cap_reclaim_work(mdsc);
2141 }
2142 
2143 void ceph_queue_cap_reclaim_work(struct ceph_mds_client *mdsc)
2144 {
2145 	if (mdsc->stopping)
2146 		return;
2147 
2148         if (queue_work(mdsc->fsc->cap_wq, &mdsc->cap_reclaim_work)) {
2149                 dout("caps reclaim work queued\n");
2150         } else {
2151                 dout("failed to queue caps release work\n");
2152         }
2153 }
2154 
2155 void ceph_reclaim_caps_nr(struct ceph_mds_client *mdsc, int nr)
2156 {
2157 	int val;
2158 	if (!nr)
2159 		return;
2160 	val = atomic_add_return(nr, &mdsc->cap_reclaim_pending);
2161 	if ((val % CEPH_CAPS_PER_RELEASE) < nr) {
2162 		atomic_set(&mdsc->cap_reclaim_pending, 0);
2163 		ceph_queue_cap_reclaim_work(mdsc);
2164 	}
2165 }
2166 
2167 /*
2168  * requests
2169  */
2170 
2171 int ceph_alloc_readdir_reply_buffer(struct ceph_mds_request *req,
2172 				    struct inode *dir)
2173 {
2174 	struct ceph_inode_info *ci = ceph_inode(dir);
2175 	struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
2176 	struct ceph_mount_options *opt = req->r_mdsc->fsc->mount_options;
2177 	size_t size = sizeof(struct ceph_mds_reply_dir_entry);
2178 	unsigned int num_entries;
2179 	int order;
2180 
2181 	spin_lock(&ci->i_ceph_lock);
2182 	num_entries = ci->i_files + ci->i_subdirs;
2183 	spin_unlock(&ci->i_ceph_lock);
2184 	num_entries = max(num_entries, 1U);
2185 	num_entries = min(num_entries, opt->max_readdir);
2186 
2187 	order = get_order(size * num_entries);
2188 	while (order >= 0) {
2189 		rinfo->dir_entries = (void*)__get_free_pages(GFP_KERNEL |
2190 							     __GFP_NOWARN,
2191 							     order);
2192 		if (rinfo->dir_entries)
2193 			break;
2194 		order--;
2195 	}
2196 	if (!rinfo->dir_entries)
2197 		return -ENOMEM;
2198 
2199 	num_entries = (PAGE_SIZE << order) / size;
2200 	num_entries = min(num_entries, opt->max_readdir);
2201 
2202 	rinfo->dir_buf_size = PAGE_SIZE << order;
2203 	req->r_num_caps = num_entries + 1;
2204 	req->r_args.readdir.max_entries = cpu_to_le32(num_entries);
2205 	req->r_args.readdir.max_bytes = cpu_to_le32(opt->max_readdir_bytes);
2206 	return 0;
2207 }
2208 
2209 /*
2210  * Create an mds request.
2211  */
2212 struct ceph_mds_request *
2213 ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode)
2214 {
2215 	struct ceph_mds_request *req;
2216 
2217 	req = kmem_cache_zalloc(ceph_mds_request_cachep, GFP_NOFS);
2218 	if (!req)
2219 		return ERR_PTR(-ENOMEM);
2220 
2221 	mutex_init(&req->r_fill_mutex);
2222 	req->r_mdsc = mdsc;
2223 	req->r_started = jiffies;
2224 	req->r_start_latency = ktime_get();
2225 	req->r_resend_mds = -1;
2226 	INIT_LIST_HEAD(&req->r_unsafe_dir_item);
2227 	INIT_LIST_HEAD(&req->r_unsafe_target_item);
2228 	req->r_fmode = -1;
2229 	kref_init(&req->r_kref);
2230 	RB_CLEAR_NODE(&req->r_node);
2231 	INIT_LIST_HEAD(&req->r_wait);
2232 	init_completion(&req->r_completion);
2233 	init_completion(&req->r_safe_completion);
2234 	INIT_LIST_HEAD(&req->r_unsafe_item);
2235 
2236 	ktime_get_coarse_real_ts64(&req->r_stamp);
2237 
2238 	req->r_op = op;
2239 	req->r_direct_mode = mode;
2240 	return req;
2241 }
2242 
2243 /*
2244  * return oldest (lowest) request, tid in request tree, 0 if none.
2245  *
2246  * called under mdsc->mutex.
2247  */
2248 static struct ceph_mds_request *__get_oldest_req(struct ceph_mds_client *mdsc)
2249 {
2250 	if (RB_EMPTY_ROOT(&mdsc->request_tree))
2251 		return NULL;
2252 	return rb_entry(rb_first(&mdsc->request_tree),
2253 			struct ceph_mds_request, r_node);
2254 }
2255 
2256 static inline  u64 __get_oldest_tid(struct ceph_mds_client *mdsc)
2257 {
2258 	return mdsc->oldest_tid;
2259 }
2260 
2261 /*
2262  * Build a dentry's path.  Allocate on heap; caller must kfree.  Based
2263  * on build_path_from_dentry in fs/cifs/dir.c.
2264  *
2265  * If @stop_on_nosnap, generate path relative to the first non-snapped
2266  * inode.
2267  *
2268  * Encode hidden .snap dirs as a double /, i.e.
2269  *   foo/.snap/bar -> foo//bar
2270  */
2271 char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase,
2272 			   int stop_on_nosnap)
2273 {
2274 	struct dentry *temp;
2275 	char *path;
2276 	int pos;
2277 	unsigned seq;
2278 	u64 base;
2279 
2280 	if (!dentry)
2281 		return ERR_PTR(-EINVAL);
2282 
2283 	path = __getname();
2284 	if (!path)
2285 		return ERR_PTR(-ENOMEM);
2286 retry:
2287 	pos = PATH_MAX - 1;
2288 	path[pos] = '\0';
2289 
2290 	seq = read_seqbegin(&rename_lock);
2291 	rcu_read_lock();
2292 	temp = dentry;
2293 	for (;;) {
2294 		struct inode *inode;
2295 
2296 		spin_lock(&temp->d_lock);
2297 		inode = d_inode(temp);
2298 		if (inode && ceph_snap(inode) == CEPH_SNAPDIR) {
2299 			dout("build_path path+%d: %p SNAPDIR\n",
2300 			     pos, temp);
2301 		} else if (stop_on_nosnap && inode && dentry != temp &&
2302 			   ceph_snap(inode) == CEPH_NOSNAP) {
2303 			spin_unlock(&temp->d_lock);
2304 			pos++; /* get rid of any prepended '/' */
2305 			break;
2306 		} else {
2307 			pos -= temp->d_name.len;
2308 			if (pos < 0) {
2309 				spin_unlock(&temp->d_lock);
2310 				break;
2311 			}
2312 			memcpy(path + pos, temp->d_name.name, temp->d_name.len);
2313 		}
2314 		spin_unlock(&temp->d_lock);
2315 		temp = READ_ONCE(temp->d_parent);
2316 
2317 		/* Are we at the root? */
2318 		if (IS_ROOT(temp))
2319 			break;
2320 
2321 		/* Are we out of buffer? */
2322 		if (--pos < 0)
2323 			break;
2324 
2325 		path[pos] = '/';
2326 	}
2327 	base = ceph_ino(d_inode(temp));
2328 	rcu_read_unlock();
2329 
2330 	if (read_seqretry(&rename_lock, seq))
2331 		goto retry;
2332 
2333 	if (pos < 0) {
2334 		/*
2335 		 * A rename didn't occur, but somehow we didn't end up where
2336 		 * we thought we would. Throw a warning and try again.
2337 		 */
2338 		pr_warn("build_path did not end path lookup where "
2339 			"expected, pos is %d\n", pos);
2340 		goto retry;
2341 	}
2342 
2343 	*pbase = base;
2344 	*plen = PATH_MAX - 1 - pos;
2345 	dout("build_path on %p %d built %llx '%.*s'\n",
2346 	     dentry, d_count(dentry), base, *plen, path + pos);
2347 	return path + pos;
2348 }
2349 
2350 static int build_dentry_path(struct dentry *dentry, struct inode *dir,
2351 			     const char **ppath, int *ppathlen, u64 *pino,
2352 			     bool *pfreepath, bool parent_locked)
2353 {
2354 	char *path;
2355 
2356 	rcu_read_lock();
2357 	if (!dir)
2358 		dir = d_inode_rcu(dentry->d_parent);
2359 	if (dir && parent_locked && ceph_snap(dir) == CEPH_NOSNAP) {
2360 		*pino = ceph_ino(dir);
2361 		rcu_read_unlock();
2362 		*ppath = dentry->d_name.name;
2363 		*ppathlen = dentry->d_name.len;
2364 		return 0;
2365 	}
2366 	rcu_read_unlock();
2367 	path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
2368 	if (IS_ERR(path))
2369 		return PTR_ERR(path);
2370 	*ppath = path;
2371 	*pfreepath = true;
2372 	return 0;
2373 }
2374 
2375 static int build_inode_path(struct inode *inode,
2376 			    const char **ppath, int *ppathlen, u64 *pino,
2377 			    bool *pfreepath)
2378 {
2379 	struct dentry *dentry;
2380 	char *path;
2381 
2382 	if (ceph_snap(inode) == CEPH_NOSNAP) {
2383 		*pino = ceph_ino(inode);
2384 		*ppathlen = 0;
2385 		return 0;
2386 	}
2387 	dentry = d_find_alias(inode);
2388 	path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
2389 	dput(dentry);
2390 	if (IS_ERR(path))
2391 		return PTR_ERR(path);
2392 	*ppath = path;
2393 	*pfreepath = true;
2394 	return 0;
2395 }
2396 
2397 /*
2398  * request arguments may be specified via an inode *, a dentry *, or
2399  * an explicit ino+path.
2400  */
2401 static int set_request_path_attr(struct inode *rinode, struct dentry *rdentry,
2402 				  struct inode *rdiri, const char *rpath,
2403 				  u64 rino, const char **ppath, int *pathlen,
2404 				  u64 *ino, bool *freepath, bool parent_locked)
2405 {
2406 	int r = 0;
2407 
2408 	if (rinode) {
2409 		r = build_inode_path(rinode, ppath, pathlen, ino, freepath);
2410 		dout(" inode %p %llx.%llx\n", rinode, ceph_ino(rinode),
2411 		     ceph_snap(rinode));
2412 	} else if (rdentry) {
2413 		r = build_dentry_path(rdentry, rdiri, ppath, pathlen, ino,
2414 					freepath, parent_locked);
2415 		dout(" dentry %p %llx/%.*s\n", rdentry, *ino, *pathlen,
2416 		     *ppath);
2417 	} else if (rpath || rino) {
2418 		*ino = rino;
2419 		*ppath = rpath;
2420 		*pathlen = rpath ? strlen(rpath) : 0;
2421 		dout(" path %.*s\n", *pathlen, rpath);
2422 	}
2423 
2424 	return r;
2425 }
2426 
2427 /*
2428  * called under mdsc->mutex
2429  */
2430 static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
2431 					       struct ceph_mds_request *req,
2432 					       int mds, bool drop_cap_releases)
2433 {
2434 	struct ceph_msg *msg;
2435 	struct ceph_mds_request_head *head;
2436 	const char *path1 = NULL;
2437 	const char *path2 = NULL;
2438 	u64 ino1 = 0, ino2 = 0;
2439 	int pathlen1 = 0, pathlen2 = 0;
2440 	bool freepath1 = false, freepath2 = false;
2441 	int len;
2442 	u16 releases;
2443 	void *p, *end;
2444 	int ret;
2445 
2446 	ret = set_request_path_attr(req->r_inode, req->r_dentry,
2447 			      req->r_parent, req->r_path1, req->r_ino1.ino,
2448 			      &path1, &pathlen1, &ino1, &freepath1,
2449 			      test_bit(CEPH_MDS_R_PARENT_LOCKED,
2450 					&req->r_req_flags));
2451 	if (ret < 0) {
2452 		msg = ERR_PTR(ret);
2453 		goto out;
2454 	}
2455 
2456 	/* If r_old_dentry is set, then assume that its parent is locked */
2457 	ret = set_request_path_attr(NULL, req->r_old_dentry,
2458 			      req->r_old_dentry_dir,
2459 			      req->r_path2, req->r_ino2.ino,
2460 			      &path2, &pathlen2, &ino2, &freepath2, true);
2461 	if (ret < 0) {
2462 		msg = ERR_PTR(ret);
2463 		goto out_free1;
2464 	}
2465 
2466 	len = sizeof(*head) +
2467 		pathlen1 + pathlen2 + 2*(1 + sizeof(u32) + sizeof(u64)) +
2468 		sizeof(struct ceph_timespec);
2469 
2470 	/* calculate (max) length for cap releases */
2471 	len += sizeof(struct ceph_mds_request_release) *
2472 		(!!req->r_inode_drop + !!req->r_dentry_drop +
2473 		 !!req->r_old_inode_drop + !!req->r_old_dentry_drop);
2474 	if (req->r_dentry_drop)
2475 		len += pathlen1;
2476 	if (req->r_old_dentry_drop)
2477 		len += pathlen2;
2478 
2479 	msg = ceph_msg_new2(CEPH_MSG_CLIENT_REQUEST, len, 1, GFP_NOFS, false);
2480 	if (!msg) {
2481 		msg = ERR_PTR(-ENOMEM);
2482 		goto out_free2;
2483 	}
2484 
2485 	msg->hdr.version = cpu_to_le16(2);
2486 	msg->hdr.tid = cpu_to_le64(req->r_tid);
2487 
2488 	head = msg->front.iov_base;
2489 	p = msg->front.iov_base + sizeof(*head);
2490 	end = msg->front.iov_base + msg->front.iov_len;
2491 
2492 	head->mdsmap_epoch = cpu_to_le32(mdsc->mdsmap->m_epoch);
2493 	head->op = cpu_to_le32(req->r_op);
2494 	head->caller_uid = cpu_to_le32(from_kuid(&init_user_ns, req->r_uid));
2495 	head->caller_gid = cpu_to_le32(from_kgid(&init_user_ns, req->r_gid));
2496 	head->ino = cpu_to_le64(req->r_deleg_ino);
2497 	head->args = req->r_args;
2498 
2499 	ceph_encode_filepath(&p, end, ino1, path1);
2500 	ceph_encode_filepath(&p, end, ino2, path2);
2501 
2502 	/* make note of release offset, in case we need to replay */
2503 	req->r_request_release_offset = p - msg->front.iov_base;
2504 
2505 	/* cap releases */
2506 	releases = 0;
2507 	if (req->r_inode_drop)
2508 		releases += ceph_encode_inode_release(&p,
2509 		      req->r_inode ? req->r_inode : d_inode(req->r_dentry),
2510 		      mds, req->r_inode_drop, req->r_inode_unless,
2511 		      req->r_op == CEPH_MDS_OP_READDIR);
2512 	if (req->r_dentry_drop)
2513 		releases += ceph_encode_dentry_release(&p, req->r_dentry,
2514 				req->r_parent, mds, req->r_dentry_drop,
2515 				req->r_dentry_unless);
2516 	if (req->r_old_dentry_drop)
2517 		releases += ceph_encode_dentry_release(&p, req->r_old_dentry,
2518 				req->r_old_dentry_dir, mds,
2519 				req->r_old_dentry_drop,
2520 				req->r_old_dentry_unless);
2521 	if (req->r_old_inode_drop)
2522 		releases += ceph_encode_inode_release(&p,
2523 		      d_inode(req->r_old_dentry),
2524 		      mds, req->r_old_inode_drop, req->r_old_inode_unless, 0);
2525 
2526 	if (drop_cap_releases) {
2527 		releases = 0;
2528 		p = msg->front.iov_base + req->r_request_release_offset;
2529 	}
2530 
2531 	head->num_releases = cpu_to_le16(releases);
2532 
2533 	/* time stamp */
2534 	{
2535 		struct ceph_timespec ts;
2536 		ceph_encode_timespec64(&ts, &req->r_stamp);
2537 		ceph_encode_copy(&p, &ts, sizeof(ts));
2538 	}
2539 
2540 	if (WARN_ON_ONCE(p > end)) {
2541 		ceph_msg_put(msg);
2542 		msg = ERR_PTR(-ERANGE);
2543 		goto out_free2;
2544 	}
2545 
2546 	msg->front.iov_len = p - msg->front.iov_base;
2547 	msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
2548 
2549 	if (req->r_pagelist) {
2550 		struct ceph_pagelist *pagelist = req->r_pagelist;
2551 		ceph_msg_data_add_pagelist(msg, pagelist);
2552 		msg->hdr.data_len = cpu_to_le32(pagelist->length);
2553 	} else {
2554 		msg->hdr.data_len = 0;
2555 	}
2556 
2557 	msg->hdr.data_off = cpu_to_le16(0);
2558 
2559 out_free2:
2560 	if (freepath2)
2561 		ceph_mdsc_free_path((char *)path2, pathlen2);
2562 out_free1:
2563 	if (freepath1)
2564 		ceph_mdsc_free_path((char *)path1, pathlen1);
2565 out:
2566 	return msg;
2567 }
2568 
2569 /*
2570  * called under mdsc->mutex if error, under no mutex if
2571  * success.
2572  */
2573 static void complete_request(struct ceph_mds_client *mdsc,
2574 			     struct ceph_mds_request *req)
2575 {
2576 	req->r_end_latency = ktime_get();
2577 
2578 	if (req->r_callback)
2579 		req->r_callback(mdsc, req);
2580 	complete_all(&req->r_completion);
2581 }
2582 
2583 /*
2584  * called under mdsc->mutex
2585  */
2586 static int __prepare_send_request(struct ceph_mds_client *mdsc,
2587 				  struct ceph_mds_request *req,
2588 				  int mds, bool drop_cap_releases)
2589 {
2590 	struct ceph_mds_request_head *rhead;
2591 	struct ceph_msg *msg;
2592 	int flags = 0;
2593 
2594 	req->r_attempts++;
2595 	if (req->r_inode) {
2596 		struct ceph_cap *cap =
2597 			ceph_get_cap_for_mds(ceph_inode(req->r_inode), mds);
2598 
2599 		if (cap)
2600 			req->r_sent_on_mseq = cap->mseq;
2601 		else
2602 			req->r_sent_on_mseq = -1;
2603 	}
2604 	dout("prepare_send_request %p tid %lld %s (attempt %d)\n", req,
2605 	     req->r_tid, ceph_mds_op_name(req->r_op), req->r_attempts);
2606 
2607 	if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
2608 		void *p;
2609 		/*
2610 		 * Replay.  Do not regenerate message (and rebuild
2611 		 * paths, etc.); just use the original message.
2612 		 * Rebuilding paths will break for renames because
2613 		 * d_move mangles the src name.
2614 		 */
2615 		msg = req->r_request;
2616 		rhead = msg->front.iov_base;
2617 
2618 		flags = le32_to_cpu(rhead->flags);
2619 		flags |= CEPH_MDS_FLAG_REPLAY;
2620 		rhead->flags = cpu_to_le32(flags);
2621 
2622 		if (req->r_target_inode)
2623 			rhead->ino = cpu_to_le64(ceph_ino(req->r_target_inode));
2624 
2625 		rhead->num_retry = req->r_attempts - 1;
2626 
2627 		/* remove cap/dentry releases from message */
2628 		rhead->num_releases = 0;
2629 
2630 		/* time stamp */
2631 		p = msg->front.iov_base + req->r_request_release_offset;
2632 		{
2633 			struct ceph_timespec ts;
2634 			ceph_encode_timespec64(&ts, &req->r_stamp);
2635 			ceph_encode_copy(&p, &ts, sizeof(ts));
2636 		}
2637 
2638 		msg->front.iov_len = p - msg->front.iov_base;
2639 		msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
2640 		return 0;
2641 	}
2642 
2643 	if (req->r_request) {
2644 		ceph_msg_put(req->r_request);
2645 		req->r_request = NULL;
2646 	}
2647 	msg = create_request_message(mdsc, req, mds, drop_cap_releases);
2648 	if (IS_ERR(msg)) {
2649 		req->r_err = PTR_ERR(msg);
2650 		return PTR_ERR(msg);
2651 	}
2652 	req->r_request = msg;
2653 
2654 	rhead = msg->front.iov_base;
2655 	rhead->oldest_client_tid = cpu_to_le64(__get_oldest_tid(mdsc));
2656 	if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags))
2657 		flags |= CEPH_MDS_FLAG_REPLAY;
2658 	if (test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags))
2659 		flags |= CEPH_MDS_FLAG_ASYNC;
2660 	if (req->r_parent)
2661 		flags |= CEPH_MDS_FLAG_WANT_DENTRY;
2662 	rhead->flags = cpu_to_le32(flags);
2663 	rhead->num_fwd = req->r_num_fwd;
2664 	rhead->num_retry = req->r_attempts - 1;
2665 
2666 	dout(" r_parent = %p\n", req->r_parent);
2667 	return 0;
2668 }
2669 
2670 /*
2671  * called under mdsc->mutex
2672  */
2673 static int __send_request(struct ceph_mds_client *mdsc,
2674 			  struct ceph_mds_session *session,
2675 			  struct ceph_mds_request *req,
2676 			  bool drop_cap_releases)
2677 {
2678 	int err;
2679 
2680 	err = __prepare_send_request(mdsc, req, session->s_mds,
2681 				     drop_cap_releases);
2682 	if (!err) {
2683 		ceph_msg_get(req->r_request);
2684 		ceph_con_send(&session->s_con, req->r_request);
2685 	}
2686 
2687 	return err;
2688 }
2689 
2690 /*
2691  * send request, or put it on the appropriate wait list.
2692  */
2693 static void __do_request(struct ceph_mds_client *mdsc,
2694 			struct ceph_mds_request *req)
2695 {
2696 	struct ceph_mds_session *session = NULL;
2697 	int mds = -1;
2698 	int err = 0;
2699 	bool random;
2700 
2701 	if (req->r_err || test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags)) {
2702 		if (test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags))
2703 			__unregister_request(mdsc, req);
2704 		return;
2705 	}
2706 
2707 	if (req->r_timeout &&
2708 	    time_after_eq(jiffies, req->r_started + req->r_timeout)) {
2709 		dout("do_request timed out\n");
2710 		err = -ETIMEDOUT;
2711 		goto finish;
2712 	}
2713 	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_SHUTDOWN) {
2714 		dout("do_request forced umount\n");
2715 		err = -EIO;
2716 		goto finish;
2717 	}
2718 	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_MOUNTING) {
2719 		if (mdsc->mdsmap_err) {
2720 			err = mdsc->mdsmap_err;
2721 			dout("do_request mdsmap err %d\n", err);
2722 			goto finish;
2723 		}
2724 		if (mdsc->mdsmap->m_epoch == 0) {
2725 			dout("do_request no mdsmap, waiting for map\n");
2726 			list_add(&req->r_wait, &mdsc->waiting_for_map);
2727 			return;
2728 		}
2729 		if (!(mdsc->fsc->mount_options->flags &
2730 		      CEPH_MOUNT_OPT_MOUNTWAIT) &&
2731 		    !ceph_mdsmap_is_cluster_available(mdsc->mdsmap)) {
2732 			err = -EHOSTUNREACH;
2733 			goto finish;
2734 		}
2735 	}
2736 
2737 	put_request_session(req);
2738 
2739 	mds = __choose_mds(mdsc, req, &random);
2740 	if (mds < 0 ||
2741 	    ceph_mdsmap_get_state(mdsc->mdsmap, mds) < CEPH_MDS_STATE_ACTIVE) {
2742 		if (test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags)) {
2743 			err = -EJUKEBOX;
2744 			goto finish;
2745 		}
2746 		dout("do_request no mds or not active, waiting for map\n");
2747 		list_add(&req->r_wait, &mdsc->waiting_for_map);
2748 		return;
2749 	}
2750 
2751 	/* get, open session */
2752 	session = __ceph_lookup_mds_session(mdsc, mds);
2753 	if (!session) {
2754 		session = register_session(mdsc, mds);
2755 		if (IS_ERR(session)) {
2756 			err = PTR_ERR(session);
2757 			goto finish;
2758 		}
2759 	}
2760 	req->r_session = ceph_get_mds_session(session);
2761 
2762 	dout("do_request mds%d session %p state %s\n", mds, session,
2763 	     ceph_session_state_name(session->s_state));
2764 	if (session->s_state != CEPH_MDS_SESSION_OPEN &&
2765 	    session->s_state != CEPH_MDS_SESSION_HUNG) {
2766 		if (session->s_state == CEPH_MDS_SESSION_REJECTED) {
2767 			err = -EACCES;
2768 			goto out_session;
2769 		}
2770 		/*
2771 		 * We cannot queue async requests since the caps and delegated
2772 		 * inodes are bound to the session. Just return -EJUKEBOX and
2773 		 * let the caller retry a sync request in that case.
2774 		 */
2775 		if (test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags)) {
2776 			err = -EJUKEBOX;
2777 			goto out_session;
2778 		}
2779 		if (session->s_state == CEPH_MDS_SESSION_NEW ||
2780 		    session->s_state == CEPH_MDS_SESSION_CLOSING) {
2781 			err = __open_session(mdsc, session);
2782 			if (err)
2783 				goto out_session;
2784 			/* retry the same mds later */
2785 			if (random)
2786 				req->r_resend_mds = mds;
2787 		}
2788 		list_add(&req->r_wait, &session->s_waiting);
2789 		goto out_session;
2790 	}
2791 
2792 	/* send request */
2793 	req->r_resend_mds = -1;   /* forget any previous mds hint */
2794 
2795 	if (req->r_request_started == 0)   /* note request start time */
2796 		req->r_request_started = jiffies;
2797 
2798 	err = __send_request(mdsc, session, req, false);
2799 
2800 out_session:
2801 	ceph_put_mds_session(session);
2802 finish:
2803 	if (err) {
2804 		dout("__do_request early error %d\n", err);
2805 		req->r_err = err;
2806 		complete_request(mdsc, req);
2807 		__unregister_request(mdsc, req);
2808 	}
2809 	return;
2810 }
2811 
2812 /*
2813  * called under mdsc->mutex
2814  */
2815 static void __wake_requests(struct ceph_mds_client *mdsc,
2816 			    struct list_head *head)
2817 {
2818 	struct ceph_mds_request *req;
2819 	LIST_HEAD(tmp_list);
2820 
2821 	list_splice_init(head, &tmp_list);
2822 
2823 	while (!list_empty(&tmp_list)) {
2824 		req = list_entry(tmp_list.next,
2825 				 struct ceph_mds_request, r_wait);
2826 		list_del_init(&req->r_wait);
2827 		dout(" wake request %p tid %llu\n", req, req->r_tid);
2828 		__do_request(mdsc, req);
2829 	}
2830 }
2831 
2832 /*
2833  * Wake up threads with requests pending for @mds, so that they can
2834  * resubmit their requests to a possibly different mds.
2835  */
2836 static void kick_requests(struct ceph_mds_client *mdsc, int mds)
2837 {
2838 	struct ceph_mds_request *req;
2839 	struct rb_node *p = rb_first(&mdsc->request_tree);
2840 
2841 	dout("kick_requests mds%d\n", mds);
2842 	while (p) {
2843 		req = rb_entry(p, struct ceph_mds_request, r_node);
2844 		p = rb_next(p);
2845 		if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags))
2846 			continue;
2847 		if (req->r_attempts > 0)
2848 			continue; /* only new requests */
2849 		if (req->r_session &&
2850 		    req->r_session->s_mds == mds) {
2851 			dout(" kicking tid %llu\n", req->r_tid);
2852 			list_del_init(&req->r_wait);
2853 			__do_request(mdsc, req);
2854 		}
2855 	}
2856 }
2857 
2858 int ceph_mdsc_submit_request(struct ceph_mds_client *mdsc, struct inode *dir,
2859 			      struct ceph_mds_request *req)
2860 {
2861 	int err = 0;
2862 
2863 	/* take CAP_PIN refs for r_inode, r_parent, r_old_dentry */
2864 	if (req->r_inode)
2865 		ceph_get_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
2866 	if (req->r_parent) {
2867 		struct ceph_inode_info *ci = ceph_inode(req->r_parent);
2868 		int fmode = (req->r_op & CEPH_MDS_OP_WRITE) ?
2869 			    CEPH_FILE_MODE_WR : CEPH_FILE_MODE_RD;
2870 		spin_lock(&ci->i_ceph_lock);
2871 		ceph_take_cap_refs(ci, CEPH_CAP_PIN, false);
2872 		__ceph_touch_fmode(ci, mdsc, fmode);
2873 		spin_unlock(&ci->i_ceph_lock);
2874 		ihold(req->r_parent);
2875 	}
2876 	if (req->r_old_dentry_dir)
2877 		ceph_get_cap_refs(ceph_inode(req->r_old_dentry_dir),
2878 				  CEPH_CAP_PIN);
2879 
2880 	if (req->r_inode) {
2881 		err = ceph_wait_on_async_create(req->r_inode);
2882 		if (err) {
2883 			dout("%s: wait for async create returned: %d\n",
2884 			     __func__, err);
2885 			return err;
2886 		}
2887 	}
2888 
2889 	if (!err && req->r_old_inode) {
2890 		err = ceph_wait_on_async_create(req->r_old_inode);
2891 		if (err) {
2892 			dout("%s: wait for async create returned: %d\n",
2893 			     __func__, err);
2894 			return err;
2895 		}
2896 	}
2897 
2898 	dout("submit_request on %p for inode %p\n", req, dir);
2899 	mutex_lock(&mdsc->mutex);
2900 	__register_request(mdsc, req, dir);
2901 	__do_request(mdsc, req);
2902 	err = req->r_err;
2903 	mutex_unlock(&mdsc->mutex);
2904 	return err;
2905 }
2906 
2907 static int ceph_mdsc_wait_request(struct ceph_mds_client *mdsc,
2908 				  struct ceph_mds_request *req)
2909 {
2910 	int err;
2911 
2912 	/* wait */
2913 	dout("do_request waiting\n");
2914 	if (!req->r_timeout && req->r_wait_for_completion) {
2915 		err = req->r_wait_for_completion(mdsc, req);
2916 	} else {
2917 		long timeleft = wait_for_completion_killable_timeout(
2918 					&req->r_completion,
2919 					ceph_timeout_jiffies(req->r_timeout));
2920 		if (timeleft > 0)
2921 			err = 0;
2922 		else if (!timeleft)
2923 			err = -ETIMEDOUT;  /* timed out */
2924 		else
2925 			err = timeleft;  /* killed */
2926 	}
2927 	dout("do_request waited, got %d\n", err);
2928 	mutex_lock(&mdsc->mutex);
2929 
2930 	/* only abort if we didn't race with a real reply */
2931 	if (test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags)) {
2932 		err = le32_to_cpu(req->r_reply_info.head->result);
2933 	} else if (err < 0) {
2934 		dout("aborted request %lld with %d\n", req->r_tid, err);
2935 
2936 		/*
2937 		 * ensure we aren't running concurrently with
2938 		 * ceph_fill_trace or ceph_readdir_prepopulate, which
2939 		 * rely on locks (dir mutex) held by our caller.
2940 		 */
2941 		mutex_lock(&req->r_fill_mutex);
2942 		req->r_err = err;
2943 		set_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags);
2944 		mutex_unlock(&req->r_fill_mutex);
2945 
2946 		if (req->r_parent &&
2947 		    (req->r_op & CEPH_MDS_OP_WRITE))
2948 			ceph_invalidate_dir_request(req);
2949 	} else {
2950 		err = req->r_err;
2951 	}
2952 
2953 	mutex_unlock(&mdsc->mutex);
2954 	return err;
2955 }
2956 
2957 /*
2958  * Synchrously perform an mds request.  Take care of all of the
2959  * session setup, forwarding, retry details.
2960  */
2961 int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
2962 			 struct inode *dir,
2963 			 struct ceph_mds_request *req)
2964 {
2965 	int err;
2966 
2967 	dout("do_request on %p\n", req);
2968 
2969 	/* issue */
2970 	err = ceph_mdsc_submit_request(mdsc, dir, req);
2971 	if (!err)
2972 		err = ceph_mdsc_wait_request(mdsc, req);
2973 	dout("do_request %p done, result %d\n", req, err);
2974 	return err;
2975 }
2976 
2977 /*
2978  * Invalidate dir's completeness, dentry lease state on an aborted MDS
2979  * namespace request.
2980  */
2981 void ceph_invalidate_dir_request(struct ceph_mds_request *req)
2982 {
2983 	struct inode *dir = req->r_parent;
2984 	struct inode *old_dir = req->r_old_dentry_dir;
2985 
2986 	dout("invalidate_dir_request %p %p (complete, lease(s))\n", dir, old_dir);
2987 
2988 	ceph_dir_clear_complete(dir);
2989 	if (old_dir)
2990 		ceph_dir_clear_complete(old_dir);
2991 	if (req->r_dentry)
2992 		ceph_invalidate_dentry_lease(req->r_dentry);
2993 	if (req->r_old_dentry)
2994 		ceph_invalidate_dentry_lease(req->r_old_dentry);
2995 }
2996 
2997 /*
2998  * Handle mds reply.
2999  *
3000  * We take the session mutex and parse and process the reply immediately.
3001  * This preserves the logical ordering of replies, capabilities, etc., sent
3002  * by the MDS as they are applied to our local cache.
3003  */
3004 static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
3005 {
3006 	struct ceph_mds_client *mdsc = session->s_mdsc;
3007 	struct ceph_mds_request *req;
3008 	struct ceph_mds_reply_head *head = msg->front.iov_base;
3009 	struct ceph_mds_reply_info_parsed *rinfo;  /* parsed reply info */
3010 	struct ceph_snap_realm *realm;
3011 	u64 tid;
3012 	int err, result;
3013 	int mds = session->s_mds;
3014 
3015 	if (msg->front.iov_len < sizeof(*head)) {
3016 		pr_err("mdsc_handle_reply got corrupt (short) reply\n");
3017 		ceph_msg_dump(msg);
3018 		return;
3019 	}
3020 
3021 	/* get request, session */
3022 	tid = le64_to_cpu(msg->hdr.tid);
3023 	mutex_lock(&mdsc->mutex);
3024 	req = lookup_get_request(mdsc, tid);
3025 	if (!req) {
3026 		dout("handle_reply on unknown tid %llu\n", tid);
3027 		mutex_unlock(&mdsc->mutex);
3028 		return;
3029 	}
3030 	dout("handle_reply %p\n", req);
3031 
3032 	/* correct session? */
3033 	if (req->r_session != session) {
3034 		pr_err("mdsc_handle_reply got %llu on session mds%d"
3035 		       " not mds%d\n", tid, session->s_mds,
3036 		       req->r_session ? req->r_session->s_mds : -1);
3037 		mutex_unlock(&mdsc->mutex);
3038 		goto out;
3039 	}
3040 
3041 	/* dup? */
3042 	if ((test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags) && !head->safe) ||
3043 	    (test_bit(CEPH_MDS_R_GOT_SAFE, &req->r_req_flags) && head->safe)) {
3044 		pr_warn("got a dup %s reply on %llu from mds%d\n",
3045 			   head->safe ? "safe" : "unsafe", tid, mds);
3046 		mutex_unlock(&mdsc->mutex);
3047 		goto out;
3048 	}
3049 	if (test_bit(CEPH_MDS_R_GOT_SAFE, &req->r_req_flags)) {
3050 		pr_warn("got unsafe after safe on %llu from mds%d\n",
3051 			   tid, mds);
3052 		mutex_unlock(&mdsc->mutex);
3053 		goto out;
3054 	}
3055 
3056 	result = le32_to_cpu(head->result);
3057 
3058 	/*
3059 	 * Handle an ESTALE
3060 	 * if we're not talking to the authority, send to them
3061 	 * if the authority has changed while we weren't looking,
3062 	 * send to new authority
3063 	 * Otherwise we just have to return an ESTALE
3064 	 */
3065 	if (result == -ESTALE) {
3066 		dout("got ESTALE on request %llu\n", req->r_tid);
3067 		req->r_resend_mds = -1;
3068 		if (req->r_direct_mode != USE_AUTH_MDS) {
3069 			dout("not using auth, setting for that now\n");
3070 			req->r_direct_mode = USE_AUTH_MDS;
3071 			__do_request(mdsc, req);
3072 			mutex_unlock(&mdsc->mutex);
3073 			goto out;
3074 		} else  {
3075 			int mds = __choose_mds(mdsc, req, NULL);
3076 			if (mds >= 0 && mds != req->r_session->s_mds) {
3077 				dout("but auth changed, so resending\n");
3078 				__do_request(mdsc, req);
3079 				mutex_unlock(&mdsc->mutex);
3080 				goto out;
3081 			}
3082 		}
3083 		dout("have to return ESTALE on request %llu\n", req->r_tid);
3084 	}
3085 
3086 
3087 	if (head->safe) {
3088 		set_bit(CEPH_MDS_R_GOT_SAFE, &req->r_req_flags);
3089 		__unregister_request(mdsc, req);
3090 
3091 		/* last request during umount? */
3092 		if (mdsc->stopping && !__get_oldest_req(mdsc))
3093 			complete_all(&mdsc->safe_umount_waiters);
3094 
3095 		if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
3096 			/*
3097 			 * We already handled the unsafe response, now do the
3098 			 * cleanup.  No need to examine the response; the MDS
3099 			 * doesn't include any result info in the safe
3100 			 * response.  And even if it did, there is nothing
3101 			 * useful we could do with a revised return value.
3102 			 */
3103 			dout("got safe reply %llu, mds%d\n", tid, mds);
3104 
3105 			mutex_unlock(&mdsc->mutex);
3106 			goto out;
3107 		}
3108 	} else {
3109 		set_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags);
3110 		list_add_tail(&req->r_unsafe_item, &req->r_session->s_unsafe);
3111 	}
3112 
3113 	dout("handle_reply tid %lld result %d\n", tid, result);
3114 	rinfo = &req->r_reply_info;
3115 	if (test_bit(CEPHFS_FEATURE_REPLY_ENCODING, &session->s_features))
3116 		err = parse_reply_info(session, msg, rinfo, (u64)-1);
3117 	else
3118 		err = parse_reply_info(session, msg, rinfo, session->s_con.peer_features);
3119 	mutex_unlock(&mdsc->mutex);
3120 
3121 	mutex_lock(&session->s_mutex);
3122 	if (err < 0) {
3123 		pr_err("mdsc_handle_reply got corrupt reply mds%d(tid:%lld)\n", mds, tid);
3124 		ceph_msg_dump(msg);
3125 		goto out_err;
3126 	}
3127 
3128 	/* snap trace */
3129 	realm = NULL;
3130 	if (rinfo->snapblob_len) {
3131 		down_write(&mdsc->snap_rwsem);
3132 		ceph_update_snap_trace(mdsc, rinfo->snapblob,
3133 				rinfo->snapblob + rinfo->snapblob_len,
3134 				le32_to_cpu(head->op) == CEPH_MDS_OP_RMSNAP,
3135 				&realm);
3136 		downgrade_write(&mdsc->snap_rwsem);
3137 	} else {
3138 		down_read(&mdsc->snap_rwsem);
3139 	}
3140 
3141 	/* insert trace into our cache */
3142 	mutex_lock(&req->r_fill_mutex);
3143 	current->journal_info = req;
3144 	err = ceph_fill_trace(mdsc->fsc->sb, req);
3145 	if (err == 0) {
3146 		if (result == 0 && (req->r_op == CEPH_MDS_OP_READDIR ||
3147 				    req->r_op == CEPH_MDS_OP_LSSNAP))
3148 			ceph_readdir_prepopulate(req, req->r_session);
3149 	}
3150 	current->journal_info = NULL;
3151 	mutex_unlock(&req->r_fill_mutex);
3152 
3153 	up_read(&mdsc->snap_rwsem);
3154 	if (realm)
3155 		ceph_put_snap_realm(mdsc, realm);
3156 
3157 	if (err == 0) {
3158 		if (req->r_target_inode &&
3159 		    test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
3160 			struct ceph_inode_info *ci =
3161 				ceph_inode(req->r_target_inode);
3162 			spin_lock(&ci->i_unsafe_lock);
3163 			list_add_tail(&req->r_unsafe_target_item,
3164 				      &ci->i_unsafe_iops);
3165 			spin_unlock(&ci->i_unsafe_lock);
3166 		}
3167 
3168 		ceph_unreserve_caps(mdsc, &req->r_caps_reservation);
3169 	}
3170 out_err:
3171 	mutex_lock(&mdsc->mutex);
3172 	if (!test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags)) {
3173 		if (err) {
3174 			req->r_err = err;
3175 		} else {
3176 			req->r_reply =  ceph_msg_get(msg);
3177 			set_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags);
3178 		}
3179 	} else {
3180 		dout("reply arrived after request %lld was aborted\n", tid);
3181 	}
3182 	mutex_unlock(&mdsc->mutex);
3183 
3184 	mutex_unlock(&session->s_mutex);
3185 
3186 	/* kick calling process */
3187 	complete_request(mdsc, req);
3188 
3189 	ceph_update_metadata_latency(&mdsc->metric, req->r_start_latency,
3190 				     req->r_end_latency, err);
3191 out:
3192 	ceph_mdsc_put_request(req);
3193 	return;
3194 }
3195 
3196 
3197 
3198 /*
3199  * handle mds notification that our request has been forwarded.
3200  */
3201 static void handle_forward(struct ceph_mds_client *mdsc,
3202 			   struct ceph_mds_session *session,
3203 			   struct ceph_msg *msg)
3204 {
3205 	struct ceph_mds_request *req;
3206 	u64 tid = le64_to_cpu(msg->hdr.tid);
3207 	u32 next_mds;
3208 	u32 fwd_seq;
3209 	int err = -EINVAL;
3210 	void *p = msg->front.iov_base;
3211 	void *end = p + msg->front.iov_len;
3212 
3213 	ceph_decode_need(&p, end, 2*sizeof(u32), bad);
3214 	next_mds = ceph_decode_32(&p);
3215 	fwd_seq = ceph_decode_32(&p);
3216 
3217 	mutex_lock(&mdsc->mutex);
3218 	req = lookup_get_request(mdsc, tid);
3219 	if (!req) {
3220 		dout("forward tid %llu to mds%d - req dne\n", tid, next_mds);
3221 		goto out;  /* dup reply? */
3222 	}
3223 
3224 	if (test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags)) {
3225 		dout("forward tid %llu aborted, unregistering\n", tid);
3226 		__unregister_request(mdsc, req);
3227 	} else if (fwd_seq <= req->r_num_fwd) {
3228 		dout("forward tid %llu to mds%d - old seq %d <= %d\n",
3229 		     tid, next_mds, req->r_num_fwd, fwd_seq);
3230 	} else {
3231 		/* resend. forward race not possible; mds would drop */
3232 		dout("forward tid %llu to mds%d (we resend)\n", tid, next_mds);
3233 		BUG_ON(req->r_err);
3234 		BUG_ON(test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags));
3235 		req->r_attempts = 0;
3236 		req->r_num_fwd = fwd_seq;
3237 		req->r_resend_mds = next_mds;
3238 		put_request_session(req);
3239 		__do_request(mdsc, req);
3240 	}
3241 	ceph_mdsc_put_request(req);
3242 out:
3243 	mutex_unlock(&mdsc->mutex);
3244 	return;
3245 
3246 bad:
3247 	pr_err("mdsc_handle_forward decode error err=%d\n", err);
3248 }
3249 
3250 static int __decode_session_metadata(void **p, void *end,
3251 				     bool *blacklisted)
3252 {
3253 	/* map<string,string> */
3254 	u32 n;
3255 	bool err_str;
3256 	ceph_decode_32_safe(p, end, n, bad);
3257 	while (n-- > 0) {
3258 		u32 len;
3259 		ceph_decode_32_safe(p, end, len, bad);
3260 		ceph_decode_need(p, end, len, bad);
3261 		err_str = !strncmp(*p, "error_string", len);
3262 		*p += len;
3263 		ceph_decode_32_safe(p, end, len, bad);
3264 		ceph_decode_need(p, end, len, bad);
3265 		if (err_str && strnstr(*p, "blacklisted", len))
3266 			*blacklisted = true;
3267 		*p += len;
3268 	}
3269 	return 0;
3270 bad:
3271 	return -1;
3272 }
3273 
3274 /*
3275  * handle a mds session control message
3276  */
3277 static void handle_session(struct ceph_mds_session *session,
3278 			   struct ceph_msg *msg)
3279 {
3280 	struct ceph_mds_client *mdsc = session->s_mdsc;
3281 	int mds = session->s_mds;
3282 	int msg_version = le16_to_cpu(msg->hdr.version);
3283 	void *p = msg->front.iov_base;
3284 	void *end = p + msg->front.iov_len;
3285 	struct ceph_mds_session_head *h;
3286 	u32 op;
3287 	u64 seq, features = 0;
3288 	int wake = 0;
3289 	bool blacklisted = false;
3290 
3291 	/* decode */
3292 	ceph_decode_need(&p, end, sizeof(*h), bad);
3293 	h = p;
3294 	p += sizeof(*h);
3295 
3296 	op = le32_to_cpu(h->op);
3297 	seq = le64_to_cpu(h->seq);
3298 
3299 	if (msg_version >= 3) {
3300 		u32 len;
3301 		/* version >= 2, metadata */
3302 		if (__decode_session_metadata(&p, end, &blacklisted) < 0)
3303 			goto bad;
3304 		/* version >= 3, feature bits */
3305 		ceph_decode_32_safe(&p, end, len, bad);
3306 		ceph_decode_64_safe(&p, end, features, bad);
3307 		p += len - sizeof(features);
3308 	}
3309 
3310 	mutex_lock(&mdsc->mutex);
3311 	if (op == CEPH_SESSION_CLOSE) {
3312 		ceph_get_mds_session(session);
3313 		__unregister_session(mdsc, session);
3314 	}
3315 	/* FIXME: this ttl calculation is generous */
3316 	session->s_ttl = jiffies + HZ*mdsc->mdsmap->m_session_autoclose;
3317 	mutex_unlock(&mdsc->mutex);
3318 
3319 	mutex_lock(&session->s_mutex);
3320 
3321 	dout("handle_session mds%d %s %p state %s seq %llu\n",
3322 	     mds, ceph_session_op_name(op), session,
3323 	     ceph_session_state_name(session->s_state), seq);
3324 
3325 	if (session->s_state == CEPH_MDS_SESSION_HUNG) {
3326 		session->s_state = CEPH_MDS_SESSION_OPEN;
3327 		pr_info("mds%d came back\n", session->s_mds);
3328 	}
3329 
3330 	switch (op) {
3331 	case CEPH_SESSION_OPEN:
3332 		if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
3333 			pr_info("mds%d reconnect success\n", session->s_mds);
3334 		session->s_state = CEPH_MDS_SESSION_OPEN;
3335 		session->s_features = features;
3336 		renewed_caps(mdsc, session, 0);
3337 		wake = 1;
3338 		if (mdsc->stopping)
3339 			__close_session(mdsc, session);
3340 		break;
3341 
3342 	case CEPH_SESSION_RENEWCAPS:
3343 		if (session->s_renew_seq == seq)
3344 			renewed_caps(mdsc, session, 1);
3345 		break;
3346 
3347 	case CEPH_SESSION_CLOSE:
3348 		if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
3349 			pr_info("mds%d reconnect denied\n", session->s_mds);
3350 		session->s_state = CEPH_MDS_SESSION_CLOSED;
3351 		cleanup_session_requests(mdsc, session);
3352 		remove_session_caps(session);
3353 		wake = 2; /* for good measure */
3354 		wake_up_all(&mdsc->session_close_wq);
3355 		break;
3356 
3357 	case CEPH_SESSION_STALE:
3358 		pr_info("mds%d caps went stale, renewing\n",
3359 			session->s_mds);
3360 		spin_lock(&session->s_gen_ttl_lock);
3361 		session->s_cap_gen++;
3362 		session->s_cap_ttl = jiffies - 1;
3363 		spin_unlock(&session->s_gen_ttl_lock);
3364 		send_renew_caps(mdsc, session);
3365 		break;
3366 
3367 	case CEPH_SESSION_RECALL_STATE:
3368 		ceph_trim_caps(mdsc, session, le32_to_cpu(h->max_caps));
3369 		break;
3370 
3371 	case CEPH_SESSION_FLUSHMSG:
3372 		send_flushmsg_ack(mdsc, session, seq);
3373 		break;
3374 
3375 	case CEPH_SESSION_FORCE_RO:
3376 		dout("force_session_readonly %p\n", session);
3377 		spin_lock(&session->s_cap_lock);
3378 		session->s_readonly = true;
3379 		spin_unlock(&session->s_cap_lock);
3380 		wake_up_session_caps(session, FORCE_RO);
3381 		break;
3382 
3383 	case CEPH_SESSION_REJECT:
3384 		WARN_ON(session->s_state != CEPH_MDS_SESSION_OPENING);
3385 		pr_info("mds%d rejected session\n", session->s_mds);
3386 		session->s_state = CEPH_MDS_SESSION_REJECTED;
3387 		cleanup_session_requests(mdsc, session);
3388 		remove_session_caps(session);
3389 		if (blacklisted)
3390 			mdsc->fsc->blacklisted = true;
3391 		wake = 2; /* for good measure */
3392 		break;
3393 
3394 	default:
3395 		pr_err("mdsc_handle_session bad op %d mds%d\n", op, mds);
3396 		WARN_ON(1);
3397 	}
3398 
3399 	mutex_unlock(&session->s_mutex);
3400 	if (wake) {
3401 		mutex_lock(&mdsc->mutex);
3402 		__wake_requests(mdsc, &session->s_waiting);
3403 		if (wake == 2)
3404 			kick_requests(mdsc, mds);
3405 		mutex_unlock(&mdsc->mutex);
3406 	}
3407 	if (op == CEPH_SESSION_CLOSE)
3408 		ceph_put_mds_session(session);
3409 	return;
3410 
3411 bad:
3412 	pr_err("mdsc_handle_session corrupt message mds%d len %d\n", mds,
3413 	       (int)msg->front.iov_len);
3414 	ceph_msg_dump(msg);
3415 	return;
3416 }
3417 
3418 void ceph_mdsc_release_dir_caps(struct ceph_mds_request *req)
3419 {
3420 	int dcaps;
3421 
3422 	dcaps = xchg(&req->r_dir_caps, 0);
3423 	if (dcaps) {
3424 		dout("releasing r_dir_caps=%s\n", ceph_cap_string(dcaps));
3425 		ceph_put_cap_refs(ceph_inode(req->r_parent), dcaps);
3426 	}
3427 }
3428 
3429 void ceph_mdsc_release_dir_caps_no_check(struct ceph_mds_request *req)
3430 {
3431 	int dcaps;
3432 
3433 	dcaps = xchg(&req->r_dir_caps, 0);
3434 	if (dcaps) {
3435 		dout("releasing r_dir_caps=%s\n", ceph_cap_string(dcaps));
3436 		ceph_put_cap_refs_no_check_caps(ceph_inode(req->r_parent),
3437 						dcaps);
3438 	}
3439 }
3440 
3441 /*
3442  * called under session->mutex.
3443  */
3444 static void replay_unsafe_requests(struct ceph_mds_client *mdsc,
3445 				   struct ceph_mds_session *session)
3446 {
3447 	struct ceph_mds_request *req, *nreq;
3448 	struct rb_node *p;
3449 
3450 	dout("replay_unsafe_requests mds%d\n", session->s_mds);
3451 
3452 	mutex_lock(&mdsc->mutex);
3453 	list_for_each_entry_safe(req, nreq, &session->s_unsafe, r_unsafe_item)
3454 		__send_request(mdsc, session, req, true);
3455 
3456 	/*
3457 	 * also re-send old requests when MDS enters reconnect stage. So that MDS
3458 	 * can process completed request in clientreplay stage.
3459 	 */
3460 	p = rb_first(&mdsc->request_tree);
3461 	while (p) {
3462 		req = rb_entry(p, struct ceph_mds_request, r_node);
3463 		p = rb_next(p);
3464 		if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags))
3465 			continue;
3466 		if (req->r_attempts == 0)
3467 			continue; /* only old requests */
3468 		if (!req->r_session)
3469 			continue;
3470 		if (req->r_session->s_mds != session->s_mds)
3471 			continue;
3472 
3473 		ceph_mdsc_release_dir_caps_no_check(req);
3474 
3475 		__send_request(mdsc, session, req, true);
3476 	}
3477 	mutex_unlock(&mdsc->mutex);
3478 }
3479 
3480 static int send_reconnect_partial(struct ceph_reconnect_state *recon_state)
3481 {
3482 	struct ceph_msg *reply;
3483 	struct ceph_pagelist *_pagelist;
3484 	struct page *page;
3485 	__le32 *addr;
3486 	int err = -ENOMEM;
3487 
3488 	if (!recon_state->allow_multi)
3489 		return -ENOSPC;
3490 
3491 	/* can't handle message that contains both caps and realm */
3492 	BUG_ON(!recon_state->nr_caps == !recon_state->nr_realms);
3493 
3494 	/* pre-allocate new pagelist */
3495 	_pagelist = ceph_pagelist_alloc(GFP_NOFS);
3496 	if (!_pagelist)
3497 		return -ENOMEM;
3498 
3499 	reply = ceph_msg_new2(CEPH_MSG_CLIENT_RECONNECT, 0, 1, GFP_NOFS, false);
3500 	if (!reply)
3501 		goto fail_msg;
3502 
3503 	/* placeholder for nr_caps */
3504 	err = ceph_pagelist_encode_32(_pagelist, 0);
3505 	if (err < 0)
3506 		goto fail;
3507 
3508 	if (recon_state->nr_caps) {
3509 		/* currently encoding caps */
3510 		err = ceph_pagelist_encode_32(recon_state->pagelist, 0);
3511 		if (err)
3512 			goto fail;
3513 	} else {
3514 		/* placeholder for nr_realms (currently encoding relams) */
3515 		err = ceph_pagelist_encode_32(_pagelist, 0);
3516 		if (err < 0)
3517 			goto fail;
3518 	}
3519 
3520 	err = ceph_pagelist_encode_8(recon_state->pagelist, 1);
3521 	if (err)
3522 		goto fail;
3523 
3524 	page = list_first_entry(&recon_state->pagelist->head, struct page, lru);
3525 	addr = kmap_atomic(page);
3526 	if (recon_state->nr_caps) {
3527 		/* currently encoding caps */
3528 		*addr = cpu_to_le32(recon_state->nr_caps);
3529 	} else {
3530 		/* currently encoding relams */
3531 		*(addr + 1) = cpu_to_le32(recon_state->nr_realms);
3532 	}
3533 	kunmap_atomic(addr);
3534 
3535 	reply->hdr.version = cpu_to_le16(5);
3536 	reply->hdr.compat_version = cpu_to_le16(4);
3537 
3538 	reply->hdr.data_len = cpu_to_le32(recon_state->pagelist->length);
3539 	ceph_msg_data_add_pagelist(reply, recon_state->pagelist);
3540 
3541 	ceph_con_send(&recon_state->session->s_con, reply);
3542 	ceph_pagelist_release(recon_state->pagelist);
3543 
3544 	recon_state->pagelist = _pagelist;
3545 	recon_state->nr_caps = 0;
3546 	recon_state->nr_realms = 0;
3547 	recon_state->msg_version = 5;
3548 	return 0;
3549 fail:
3550 	ceph_msg_put(reply);
3551 fail_msg:
3552 	ceph_pagelist_release(_pagelist);
3553 	return err;
3554 }
3555 
3556 /*
3557  * Encode information about a cap for a reconnect with the MDS.
3558  */
3559 static int reconnect_caps_cb(struct inode *inode, struct ceph_cap *cap,
3560 			  void *arg)
3561 {
3562 	union {
3563 		struct ceph_mds_cap_reconnect v2;
3564 		struct ceph_mds_cap_reconnect_v1 v1;
3565 	} rec;
3566 	struct ceph_inode_info *ci = cap->ci;
3567 	struct ceph_reconnect_state *recon_state = arg;
3568 	struct ceph_pagelist *pagelist = recon_state->pagelist;
3569 	int err;
3570 	u64 snap_follows;
3571 
3572 	dout(" adding %p ino %llx.%llx cap %p %lld %s\n",
3573 	     inode, ceph_vinop(inode), cap, cap->cap_id,
3574 	     ceph_cap_string(cap->issued));
3575 
3576 	spin_lock(&ci->i_ceph_lock);
3577 	cap->seq = 0;        /* reset cap seq */
3578 	cap->issue_seq = 0;  /* and issue_seq */
3579 	cap->mseq = 0;       /* and migrate_seq */
3580 	cap->cap_gen = cap->session->s_cap_gen;
3581 
3582 	/* These are lost when the session goes away */
3583 	if (S_ISDIR(inode->i_mode)) {
3584 		if (cap->issued & CEPH_CAP_DIR_CREATE) {
3585 			ceph_put_string(rcu_dereference_raw(ci->i_cached_layout.pool_ns));
3586 			memset(&ci->i_cached_layout, 0, sizeof(ci->i_cached_layout));
3587 		}
3588 		cap->issued &= ~CEPH_CAP_ANY_DIR_OPS;
3589 	}
3590 
3591 	if (recon_state->msg_version >= 2) {
3592 		rec.v2.cap_id = cpu_to_le64(cap->cap_id);
3593 		rec.v2.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
3594 		rec.v2.issued = cpu_to_le32(cap->issued);
3595 		rec.v2.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
3596 		rec.v2.pathbase = 0;
3597 		rec.v2.flock_len = (__force __le32)
3598 			((ci->i_ceph_flags & CEPH_I_ERROR_FILELOCK) ? 0 : 1);
3599 	} else {
3600 		rec.v1.cap_id = cpu_to_le64(cap->cap_id);
3601 		rec.v1.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
3602 		rec.v1.issued = cpu_to_le32(cap->issued);
3603 		rec.v1.size = cpu_to_le64(inode->i_size);
3604 		ceph_encode_timespec64(&rec.v1.mtime, &inode->i_mtime);
3605 		ceph_encode_timespec64(&rec.v1.atime, &inode->i_atime);
3606 		rec.v1.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
3607 		rec.v1.pathbase = 0;
3608 	}
3609 
3610 	if (list_empty(&ci->i_cap_snaps)) {
3611 		snap_follows = ci->i_head_snapc ? ci->i_head_snapc->seq : 0;
3612 	} else {
3613 		struct ceph_cap_snap *capsnap =
3614 			list_first_entry(&ci->i_cap_snaps,
3615 					 struct ceph_cap_snap, ci_item);
3616 		snap_follows = capsnap->follows;
3617 	}
3618 	spin_unlock(&ci->i_ceph_lock);
3619 
3620 	if (recon_state->msg_version >= 2) {
3621 		int num_fcntl_locks, num_flock_locks;
3622 		struct ceph_filelock *flocks = NULL;
3623 		size_t struct_len, total_len = sizeof(u64);
3624 		u8 struct_v = 0;
3625 
3626 encode_again:
3627 		if (rec.v2.flock_len) {
3628 			ceph_count_locks(inode, &num_fcntl_locks, &num_flock_locks);
3629 		} else {
3630 			num_fcntl_locks = 0;
3631 			num_flock_locks = 0;
3632 		}
3633 		if (num_fcntl_locks + num_flock_locks > 0) {
3634 			flocks = kmalloc_array(num_fcntl_locks + num_flock_locks,
3635 					       sizeof(struct ceph_filelock),
3636 					       GFP_NOFS);
3637 			if (!flocks) {
3638 				err = -ENOMEM;
3639 				goto out_err;
3640 			}
3641 			err = ceph_encode_locks_to_buffer(inode, flocks,
3642 							  num_fcntl_locks,
3643 							  num_flock_locks);
3644 			if (err) {
3645 				kfree(flocks);
3646 				flocks = NULL;
3647 				if (err == -ENOSPC)
3648 					goto encode_again;
3649 				goto out_err;
3650 			}
3651 		} else {
3652 			kfree(flocks);
3653 			flocks = NULL;
3654 		}
3655 
3656 		if (recon_state->msg_version >= 3) {
3657 			/* version, compat_version and struct_len */
3658 			total_len += 2 * sizeof(u8) + sizeof(u32);
3659 			struct_v = 2;
3660 		}
3661 		/*
3662 		 * number of encoded locks is stable, so copy to pagelist
3663 		 */
3664 		struct_len = 2 * sizeof(u32) +
3665 			    (num_fcntl_locks + num_flock_locks) *
3666 			    sizeof(struct ceph_filelock);
3667 		rec.v2.flock_len = cpu_to_le32(struct_len);
3668 
3669 		struct_len += sizeof(u32) + sizeof(rec.v2);
3670 
3671 		if (struct_v >= 2)
3672 			struct_len += sizeof(u64); /* snap_follows */
3673 
3674 		total_len += struct_len;
3675 
3676 		if (pagelist->length + total_len > RECONNECT_MAX_SIZE) {
3677 			err = send_reconnect_partial(recon_state);
3678 			if (err)
3679 				goto out_freeflocks;
3680 			pagelist = recon_state->pagelist;
3681 		}
3682 
3683 		err = ceph_pagelist_reserve(pagelist, total_len);
3684 		if (err)
3685 			goto out_freeflocks;
3686 
3687 		ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
3688 		if (recon_state->msg_version >= 3) {
3689 			ceph_pagelist_encode_8(pagelist, struct_v);
3690 			ceph_pagelist_encode_8(pagelist, 1);
3691 			ceph_pagelist_encode_32(pagelist, struct_len);
3692 		}
3693 		ceph_pagelist_encode_string(pagelist, NULL, 0);
3694 		ceph_pagelist_append(pagelist, &rec, sizeof(rec.v2));
3695 		ceph_locks_to_pagelist(flocks, pagelist,
3696 				       num_fcntl_locks, num_flock_locks);
3697 		if (struct_v >= 2)
3698 			ceph_pagelist_encode_64(pagelist, snap_follows);
3699 out_freeflocks:
3700 		kfree(flocks);
3701 	} else {
3702 		u64 pathbase = 0;
3703 		int pathlen = 0;
3704 		char *path = NULL;
3705 		struct dentry *dentry;
3706 
3707 		dentry = d_find_alias(inode);
3708 		if (dentry) {
3709 			path = ceph_mdsc_build_path(dentry,
3710 						&pathlen, &pathbase, 0);
3711 			dput(dentry);
3712 			if (IS_ERR(path)) {
3713 				err = PTR_ERR(path);
3714 				goto out_err;
3715 			}
3716 			rec.v1.pathbase = cpu_to_le64(pathbase);
3717 		}
3718 
3719 		err = ceph_pagelist_reserve(pagelist,
3720 					    sizeof(u64) + sizeof(u32) +
3721 					    pathlen + sizeof(rec.v1));
3722 		if (err) {
3723 			goto out_freepath;
3724 		}
3725 
3726 		ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
3727 		ceph_pagelist_encode_string(pagelist, path, pathlen);
3728 		ceph_pagelist_append(pagelist, &rec, sizeof(rec.v1));
3729 out_freepath:
3730 		ceph_mdsc_free_path(path, pathlen);
3731 	}
3732 
3733 out_err:
3734 	if (err >= 0)
3735 		recon_state->nr_caps++;
3736 	return err;
3737 }
3738 
3739 static int encode_snap_realms(struct ceph_mds_client *mdsc,
3740 			      struct ceph_reconnect_state *recon_state)
3741 {
3742 	struct rb_node *p;
3743 	struct ceph_pagelist *pagelist = recon_state->pagelist;
3744 	int err = 0;
3745 
3746 	if (recon_state->msg_version >= 4) {
3747 		err = ceph_pagelist_encode_32(pagelist, mdsc->num_snap_realms);
3748 		if (err < 0)
3749 			goto fail;
3750 	}
3751 
3752 	/*
3753 	 * snaprealms.  we provide mds with the ino, seq (version), and
3754 	 * parent for all of our realms.  If the mds has any newer info,
3755 	 * it will tell us.
3756 	 */
3757 	for (p = rb_first(&mdsc->snap_realms); p; p = rb_next(p)) {
3758 		struct ceph_snap_realm *realm =
3759 		       rb_entry(p, struct ceph_snap_realm, node);
3760 		struct ceph_mds_snaprealm_reconnect sr_rec;
3761 
3762 		if (recon_state->msg_version >= 4) {
3763 			size_t need = sizeof(u8) * 2 + sizeof(u32) +
3764 				      sizeof(sr_rec);
3765 
3766 			if (pagelist->length + need > RECONNECT_MAX_SIZE) {
3767 				err = send_reconnect_partial(recon_state);
3768 				if (err)
3769 					goto fail;
3770 				pagelist = recon_state->pagelist;
3771 			}
3772 
3773 			err = ceph_pagelist_reserve(pagelist, need);
3774 			if (err)
3775 				goto fail;
3776 
3777 			ceph_pagelist_encode_8(pagelist, 1);
3778 			ceph_pagelist_encode_8(pagelist, 1);
3779 			ceph_pagelist_encode_32(pagelist, sizeof(sr_rec));
3780 		}
3781 
3782 		dout(" adding snap realm %llx seq %lld parent %llx\n",
3783 		     realm->ino, realm->seq, realm->parent_ino);
3784 		sr_rec.ino = cpu_to_le64(realm->ino);
3785 		sr_rec.seq = cpu_to_le64(realm->seq);
3786 		sr_rec.parent = cpu_to_le64(realm->parent_ino);
3787 
3788 		err = ceph_pagelist_append(pagelist, &sr_rec, sizeof(sr_rec));
3789 		if (err)
3790 			goto fail;
3791 
3792 		recon_state->nr_realms++;
3793 	}
3794 fail:
3795 	return err;
3796 }
3797 
3798 
3799 /*
3800  * If an MDS fails and recovers, clients need to reconnect in order to
3801  * reestablish shared state.  This includes all caps issued through
3802  * this session _and_ the snap_realm hierarchy.  Because it's not
3803  * clear which snap realms the mds cares about, we send everything we
3804  * know about.. that ensures we'll then get any new info the
3805  * recovering MDS might have.
3806  *
3807  * This is a relatively heavyweight operation, but it's rare.
3808  */
3809 static void send_mds_reconnect(struct ceph_mds_client *mdsc,
3810 			       struct ceph_mds_session *session)
3811 {
3812 	struct ceph_msg *reply;
3813 	int mds = session->s_mds;
3814 	int err = -ENOMEM;
3815 	struct ceph_reconnect_state recon_state = {
3816 		.session = session,
3817 	};
3818 	LIST_HEAD(dispose);
3819 
3820 	pr_info("mds%d reconnect start\n", mds);
3821 
3822 	recon_state.pagelist = ceph_pagelist_alloc(GFP_NOFS);
3823 	if (!recon_state.pagelist)
3824 		goto fail_nopagelist;
3825 
3826 	reply = ceph_msg_new2(CEPH_MSG_CLIENT_RECONNECT, 0, 1, GFP_NOFS, false);
3827 	if (!reply)
3828 		goto fail_nomsg;
3829 
3830 	xa_destroy(&session->s_delegated_inos);
3831 
3832 	mutex_lock(&session->s_mutex);
3833 	session->s_state = CEPH_MDS_SESSION_RECONNECTING;
3834 	session->s_seq = 0;
3835 
3836 	dout("session %p state %s\n", session,
3837 	     ceph_session_state_name(session->s_state));
3838 
3839 	spin_lock(&session->s_gen_ttl_lock);
3840 	session->s_cap_gen++;
3841 	spin_unlock(&session->s_gen_ttl_lock);
3842 
3843 	spin_lock(&session->s_cap_lock);
3844 	/* don't know if session is readonly */
3845 	session->s_readonly = 0;
3846 	/*
3847 	 * notify __ceph_remove_cap() that we are composing cap reconnect.
3848 	 * If a cap get released before being added to the cap reconnect,
3849 	 * __ceph_remove_cap() should skip queuing cap release.
3850 	 */
3851 	session->s_cap_reconnect = 1;
3852 	/* drop old cap expires; we're about to reestablish that state */
3853 	detach_cap_releases(session, &dispose);
3854 	spin_unlock(&session->s_cap_lock);
3855 	dispose_cap_releases(mdsc, &dispose);
3856 
3857 	/* trim unused caps to reduce MDS's cache rejoin time */
3858 	if (mdsc->fsc->sb->s_root)
3859 		shrink_dcache_parent(mdsc->fsc->sb->s_root);
3860 
3861 	ceph_con_close(&session->s_con);
3862 	ceph_con_open(&session->s_con,
3863 		      CEPH_ENTITY_TYPE_MDS, mds,
3864 		      ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
3865 
3866 	/* replay unsafe requests */
3867 	replay_unsafe_requests(mdsc, session);
3868 
3869 	ceph_early_kick_flushing_caps(mdsc, session);
3870 
3871 	down_read(&mdsc->snap_rwsem);
3872 
3873 	/* placeholder for nr_caps */
3874 	err = ceph_pagelist_encode_32(recon_state.pagelist, 0);
3875 	if (err)
3876 		goto fail;
3877 
3878 	if (test_bit(CEPHFS_FEATURE_MULTI_RECONNECT, &session->s_features)) {
3879 		recon_state.msg_version = 3;
3880 		recon_state.allow_multi = true;
3881 	} else if (session->s_con.peer_features & CEPH_FEATURE_MDSENC) {
3882 		recon_state.msg_version = 3;
3883 	} else {
3884 		recon_state.msg_version = 2;
3885 	}
3886 	/* trsaverse this session's caps */
3887 	err = ceph_iterate_session_caps(session, reconnect_caps_cb, &recon_state);
3888 
3889 	spin_lock(&session->s_cap_lock);
3890 	session->s_cap_reconnect = 0;
3891 	spin_unlock(&session->s_cap_lock);
3892 
3893 	if (err < 0)
3894 		goto fail;
3895 
3896 	/* check if all realms can be encoded into current message */
3897 	if (mdsc->num_snap_realms) {
3898 		size_t total_len =
3899 			recon_state.pagelist->length +
3900 			mdsc->num_snap_realms *
3901 			sizeof(struct ceph_mds_snaprealm_reconnect);
3902 		if (recon_state.msg_version >= 4) {
3903 			/* number of realms */
3904 			total_len += sizeof(u32);
3905 			/* version, compat_version and struct_len */
3906 			total_len += mdsc->num_snap_realms *
3907 				     (2 * sizeof(u8) + sizeof(u32));
3908 		}
3909 		if (total_len > RECONNECT_MAX_SIZE) {
3910 			if (!recon_state.allow_multi) {
3911 				err = -ENOSPC;
3912 				goto fail;
3913 			}
3914 			if (recon_state.nr_caps) {
3915 				err = send_reconnect_partial(&recon_state);
3916 				if (err)
3917 					goto fail;
3918 			}
3919 			recon_state.msg_version = 5;
3920 		}
3921 	}
3922 
3923 	err = encode_snap_realms(mdsc, &recon_state);
3924 	if (err < 0)
3925 		goto fail;
3926 
3927 	if (recon_state.msg_version >= 5) {
3928 		err = ceph_pagelist_encode_8(recon_state.pagelist, 0);
3929 		if (err < 0)
3930 			goto fail;
3931 	}
3932 
3933 	if (recon_state.nr_caps || recon_state.nr_realms) {
3934 		struct page *page =
3935 			list_first_entry(&recon_state.pagelist->head,
3936 					struct page, lru);
3937 		__le32 *addr = kmap_atomic(page);
3938 		if (recon_state.nr_caps) {
3939 			WARN_ON(recon_state.nr_realms != mdsc->num_snap_realms);
3940 			*addr = cpu_to_le32(recon_state.nr_caps);
3941 		} else if (recon_state.msg_version >= 4) {
3942 			*(addr + 1) = cpu_to_le32(recon_state.nr_realms);
3943 		}
3944 		kunmap_atomic(addr);
3945 	}
3946 
3947 	reply->hdr.version = cpu_to_le16(recon_state.msg_version);
3948 	if (recon_state.msg_version >= 4)
3949 		reply->hdr.compat_version = cpu_to_le16(4);
3950 
3951 	reply->hdr.data_len = cpu_to_le32(recon_state.pagelist->length);
3952 	ceph_msg_data_add_pagelist(reply, recon_state.pagelist);
3953 
3954 	ceph_con_send(&session->s_con, reply);
3955 
3956 	mutex_unlock(&session->s_mutex);
3957 
3958 	mutex_lock(&mdsc->mutex);
3959 	__wake_requests(mdsc, &session->s_waiting);
3960 	mutex_unlock(&mdsc->mutex);
3961 
3962 	up_read(&mdsc->snap_rwsem);
3963 	ceph_pagelist_release(recon_state.pagelist);
3964 	return;
3965 
3966 fail:
3967 	ceph_msg_put(reply);
3968 	up_read(&mdsc->snap_rwsem);
3969 	mutex_unlock(&session->s_mutex);
3970 fail_nomsg:
3971 	ceph_pagelist_release(recon_state.pagelist);
3972 fail_nopagelist:
3973 	pr_err("error %d preparing reconnect for mds%d\n", err, mds);
3974 	return;
3975 }
3976 
3977 
3978 /*
3979  * compare old and new mdsmaps, kicking requests
3980  * and closing out old connections as necessary
3981  *
3982  * called under mdsc->mutex.
3983  */
3984 static void check_new_map(struct ceph_mds_client *mdsc,
3985 			  struct ceph_mdsmap *newmap,
3986 			  struct ceph_mdsmap *oldmap)
3987 {
3988 	int i;
3989 	int oldstate, newstate;
3990 	struct ceph_mds_session *s;
3991 
3992 	dout("check_new_map new %u old %u\n",
3993 	     newmap->m_epoch, oldmap->m_epoch);
3994 
3995 	for (i = 0; i < oldmap->possible_max_rank && i < mdsc->max_sessions; i++) {
3996 		if (!mdsc->sessions[i])
3997 			continue;
3998 		s = mdsc->sessions[i];
3999 		oldstate = ceph_mdsmap_get_state(oldmap, i);
4000 		newstate = ceph_mdsmap_get_state(newmap, i);
4001 
4002 		dout("check_new_map mds%d state %s%s -> %s%s (session %s)\n",
4003 		     i, ceph_mds_state_name(oldstate),
4004 		     ceph_mdsmap_is_laggy(oldmap, i) ? " (laggy)" : "",
4005 		     ceph_mds_state_name(newstate),
4006 		     ceph_mdsmap_is_laggy(newmap, i) ? " (laggy)" : "",
4007 		     ceph_session_state_name(s->s_state));
4008 
4009 		if (i >= newmap->possible_max_rank) {
4010 			/* force close session for stopped mds */
4011 			ceph_get_mds_session(s);
4012 			__unregister_session(mdsc, s);
4013 			__wake_requests(mdsc, &s->s_waiting);
4014 			mutex_unlock(&mdsc->mutex);
4015 
4016 			mutex_lock(&s->s_mutex);
4017 			cleanup_session_requests(mdsc, s);
4018 			remove_session_caps(s);
4019 			mutex_unlock(&s->s_mutex);
4020 
4021 			ceph_put_mds_session(s);
4022 
4023 			mutex_lock(&mdsc->mutex);
4024 			kick_requests(mdsc, i);
4025 			continue;
4026 		}
4027 
4028 		if (memcmp(ceph_mdsmap_get_addr(oldmap, i),
4029 			   ceph_mdsmap_get_addr(newmap, i),
4030 			   sizeof(struct ceph_entity_addr))) {
4031 			/* just close it */
4032 			mutex_unlock(&mdsc->mutex);
4033 			mutex_lock(&s->s_mutex);
4034 			mutex_lock(&mdsc->mutex);
4035 			ceph_con_close(&s->s_con);
4036 			mutex_unlock(&s->s_mutex);
4037 			s->s_state = CEPH_MDS_SESSION_RESTARTING;
4038 		} else if (oldstate == newstate) {
4039 			continue;  /* nothing new with this mds */
4040 		}
4041 
4042 		/*
4043 		 * send reconnect?
4044 		 */
4045 		if (s->s_state == CEPH_MDS_SESSION_RESTARTING &&
4046 		    newstate >= CEPH_MDS_STATE_RECONNECT) {
4047 			mutex_unlock(&mdsc->mutex);
4048 			send_mds_reconnect(mdsc, s);
4049 			mutex_lock(&mdsc->mutex);
4050 		}
4051 
4052 		/*
4053 		 * kick request on any mds that has gone active.
4054 		 */
4055 		if (oldstate < CEPH_MDS_STATE_ACTIVE &&
4056 		    newstate >= CEPH_MDS_STATE_ACTIVE) {
4057 			if (oldstate != CEPH_MDS_STATE_CREATING &&
4058 			    oldstate != CEPH_MDS_STATE_STARTING)
4059 				pr_info("mds%d recovery completed\n", s->s_mds);
4060 			kick_requests(mdsc, i);
4061 			mutex_unlock(&mdsc->mutex);
4062 			mutex_lock(&s->s_mutex);
4063 			mutex_lock(&mdsc->mutex);
4064 			ceph_kick_flushing_caps(mdsc, s);
4065 			mutex_unlock(&s->s_mutex);
4066 			wake_up_session_caps(s, RECONNECT);
4067 		}
4068 	}
4069 
4070 	for (i = 0; i < newmap->possible_max_rank && i < mdsc->max_sessions; i++) {
4071 		s = mdsc->sessions[i];
4072 		if (!s)
4073 			continue;
4074 		if (!ceph_mdsmap_is_laggy(newmap, i))
4075 			continue;
4076 		if (s->s_state == CEPH_MDS_SESSION_OPEN ||
4077 		    s->s_state == CEPH_MDS_SESSION_HUNG ||
4078 		    s->s_state == CEPH_MDS_SESSION_CLOSING) {
4079 			dout(" connecting to export targets of laggy mds%d\n",
4080 			     i);
4081 			__open_export_target_sessions(mdsc, s);
4082 		}
4083 	}
4084 }
4085 
4086 
4087 
4088 /*
4089  * leases
4090  */
4091 
4092 /*
4093  * caller must hold session s_mutex, dentry->d_lock
4094  */
4095 void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry)
4096 {
4097 	struct ceph_dentry_info *di = ceph_dentry(dentry);
4098 
4099 	ceph_put_mds_session(di->lease_session);
4100 	di->lease_session = NULL;
4101 }
4102 
4103 static void handle_lease(struct ceph_mds_client *mdsc,
4104 			 struct ceph_mds_session *session,
4105 			 struct ceph_msg *msg)
4106 {
4107 	struct super_block *sb = mdsc->fsc->sb;
4108 	struct inode *inode;
4109 	struct dentry *parent, *dentry;
4110 	struct ceph_dentry_info *di;
4111 	int mds = session->s_mds;
4112 	struct ceph_mds_lease *h = msg->front.iov_base;
4113 	u32 seq;
4114 	struct ceph_vino vino;
4115 	struct qstr dname;
4116 	int release = 0;
4117 
4118 	dout("handle_lease from mds%d\n", mds);
4119 
4120 	/* decode */
4121 	if (msg->front.iov_len < sizeof(*h) + sizeof(u32))
4122 		goto bad;
4123 	vino.ino = le64_to_cpu(h->ino);
4124 	vino.snap = CEPH_NOSNAP;
4125 	seq = le32_to_cpu(h->seq);
4126 	dname.len = get_unaligned_le32(h + 1);
4127 	if (msg->front.iov_len < sizeof(*h) + sizeof(u32) + dname.len)
4128 		goto bad;
4129 	dname.name = (void *)(h + 1) + sizeof(u32);
4130 
4131 	/* lookup inode */
4132 	inode = ceph_find_inode(sb, vino);
4133 	dout("handle_lease %s, ino %llx %p %.*s\n",
4134 	     ceph_lease_op_name(h->action), vino.ino, inode,
4135 	     dname.len, dname.name);
4136 
4137 	mutex_lock(&session->s_mutex);
4138 	session->s_seq++;
4139 
4140 	if (!inode) {
4141 		dout("handle_lease no inode %llx\n", vino.ino);
4142 		goto release;
4143 	}
4144 
4145 	/* dentry */
4146 	parent = d_find_alias(inode);
4147 	if (!parent) {
4148 		dout("no parent dentry on inode %p\n", inode);
4149 		WARN_ON(1);
4150 		goto release;  /* hrm... */
4151 	}
4152 	dname.hash = full_name_hash(parent, dname.name, dname.len);
4153 	dentry = d_lookup(parent, &dname);
4154 	dput(parent);
4155 	if (!dentry)
4156 		goto release;
4157 
4158 	spin_lock(&dentry->d_lock);
4159 	di = ceph_dentry(dentry);
4160 	switch (h->action) {
4161 	case CEPH_MDS_LEASE_REVOKE:
4162 		if (di->lease_session == session) {
4163 			if (ceph_seq_cmp(di->lease_seq, seq) > 0)
4164 				h->seq = cpu_to_le32(di->lease_seq);
4165 			__ceph_mdsc_drop_dentry_lease(dentry);
4166 		}
4167 		release = 1;
4168 		break;
4169 
4170 	case CEPH_MDS_LEASE_RENEW:
4171 		if (di->lease_session == session &&
4172 		    di->lease_gen == session->s_cap_gen &&
4173 		    di->lease_renew_from &&
4174 		    di->lease_renew_after == 0) {
4175 			unsigned long duration =
4176 				msecs_to_jiffies(le32_to_cpu(h->duration_ms));
4177 
4178 			di->lease_seq = seq;
4179 			di->time = di->lease_renew_from + duration;
4180 			di->lease_renew_after = di->lease_renew_from +
4181 				(duration >> 1);
4182 			di->lease_renew_from = 0;
4183 		}
4184 		break;
4185 	}
4186 	spin_unlock(&dentry->d_lock);
4187 	dput(dentry);
4188 
4189 	if (!release)
4190 		goto out;
4191 
4192 release:
4193 	/* let's just reuse the same message */
4194 	h->action = CEPH_MDS_LEASE_REVOKE_ACK;
4195 	ceph_msg_get(msg);
4196 	ceph_con_send(&session->s_con, msg);
4197 
4198 out:
4199 	mutex_unlock(&session->s_mutex);
4200 	/* avoid calling iput_final() in mds dispatch threads */
4201 	ceph_async_iput(inode);
4202 	return;
4203 
4204 bad:
4205 	pr_err("corrupt lease message\n");
4206 	ceph_msg_dump(msg);
4207 }
4208 
4209 void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
4210 			      struct dentry *dentry, char action,
4211 			      u32 seq)
4212 {
4213 	struct ceph_msg *msg;
4214 	struct ceph_mds_lease *lease;
4215 	struct inode *dir;
4216 	int len = sizeof(*lease) + sizeof(u32) + NAME_MAX;
4217 
4218 	dout("lease_send_msg identry %p %s to mds%d\n",
4219 	     dentry, ceph_lease_op_name(action), session->s_mds);
4220 
4221 	msg = ceph_msg_new(CEPH_MSG_CLIENT_LEASE, len, GFP_NOFS, false);
4222 	if (!msg)
4223 		return;
4224 	lease = msg->front.iov_base;
4225 	lease->action = action;
4226 	lease->seq = cpu_to_le32(seq);
4227 
4228 	spin_lock(&dentry->d_lock);
4229 	dir = d_inode(dentry->d_parent);
4230 	lease->ino = cpu_to_le64(ceph_ino(dir));
4231 	lease->first = lease->last = cpu_to_le64(ceph_snap(dir));
4232 
4233 	put_unaligned_le32(dentry->d_name.len, lease + 1);
4234 	memcpy((void *)(lease + 1) + 4,
4235 	       dentry->d_name.name, dentry->d_name.len);
4236 	spin_unlock(&dentry->d_lock);
4237 	/*
4238 	 * if this is a preemptive lease RELEASE, no need to
4239 	 * flush request stream, since the actual request will
4240 	 * soon follow.
4241 	 */
4242 	msg->more_to_follow = (action == CEPH_MDS_LEASE_RELEASE);
4243 
4244 	ceph_con_send(&session->s_con, msg);
4245 }
4246 
4247 /*
4248  * lock unlock sessions, to wait ongoing session activities
4249  */
4250 static void lock_unlock_sessions(struct ceph_mds_client *mdsc)
4251 {
4252 	int i;
4253 
4254 	mutex_lock(&mdsc->mutex);
4255 	for (i = 0; i < mdsc->max_sessions; i++) {
4256 		struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
4257 		if (!s)
4258 			continue;
4259 		mutex_unlock(&mdsc->mutex);
4260 		mutex_lock(&s->s_mutex);
4261 		mutex_unlock(&s->s_mutex);
4262 		ceph_put_mds_session(s);
4263 		mutex_lock(&mdsc->mutex);
4264 	}
4265 	mutex_unlock(&mdsc->mutex);
4266 }
4267 
4268 static void maybe_recover_session(struct ceph_mds_client *mdsc)
4269 {
4270 	struct ceph_fs_client *fsc = mdsc->fsc;
4271 
4272 	if (!ceph_test_mount_opt(fsc, CLEANRECOVER))
4273 		return;
4274 
4275 	if (READ_ONCE(fsc->mount_state) != CEPH_MOUNT_MOUNTED)
4276 		return;
4277 
4278 	if (!READ_ONCE(fsc->blacklisted))
4279 		return;
4280 
4281 	if (fsc->last_auto_reconnect &&
4282 	    time_before(jiffies, fsc->last_auto_reconnect + HZ * 60 * 30))
4283 		return;
4284 
4285 	pr_info("auto reconnect after blacklisted\n");
4286 	fsc->last_auto_reconnect = jiffies;
4287 	ceph_force_reconnect(fsc->sb);
4288 }
4289 
4290 bool check_session_state(struct ceph_mds_session *s)
4291 {
4292 	if (s->s_state == CEPH_MDS_SESSION_CLOSING) {
4293 		dout("resending session close request for mds%d\n",
4294 				s->s_mds);
4295 		request_close_session(s);
4296 		return false;
4297 	}
4298 	if (s->s_ttl && time_after(jiffies, s->s_ttl)) {
4299 		if (s->s_state == CEPH_MDS_SESSION_OPEN) {
4300 			s->s_state = CEPH_MDS_SESSION_HUNG;
4301 			pr_info("mds%d hung\n", s->s_mds);
4302 		}
4303 	}
4304 	if (s->s_state == CEPH_MDS_SESSION_NEW ||
4305 	    s->s_state == CEPH_MDS_SESSION_RESTARTING ||
4306 	    s->s_state == CEPH_MDS_SESSION_REJECTED)
4307 		/* this mds is failed or recovering, just wait */
4308 		return false;
4309 
4310 	return true;
4311 }
4312 
4313 /*
4314  * delayed work -- periodically trim expired leases, renew caps with mds
4315  */
4316 static void schedule_delayed(struct ceph_mds_client *mdsc)
4317 {
4318 	int delay = 5;
4319 	unsigned hz = round_jiffies_relative(HZ * delay);
4320 	schedule_delayed_work(&mdsc->delayed_work, hz);
4321 }
4322 
4323 static void delayed_work(struct work_struct *work)
4324 {
4325 	int i;
4326 	struct ceph_mds_client *mdsc =
4327 		container_of(work, struct ceph_mds_client, delayed_work.work);
4328 	int renew_interval;
4329 	int renew_caps;
4330 
4331 	dout("mdsc delayed_work\n");
4332 
4333 	if (mdsc->stopping)
4334 		return;
4335 
4336 	mutex_lock(&mdsc->mutex);
4337 	renew_interval = mdsc->mdsmap->m_session_timeout >> 2;
4338 	renew_caps = time_after_eq(jiffies, HZ*renew_interval +
4339 				   mdsc->last_renew_caps);
4340 	if (renew_caps)
4341 		mdsc->last_renew_caps = jiffies;
4342 
4343 	for (i = 0; i < mdsc->max_sessions; i++) {
4344 		struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
4345 		if (!s)
4346 			continue;
4347 
4348 		if (!check_session_state(s)) {
4349 			ceph_put_mds_session(s);
4350 			continue;
4351 		}
4352 		mutex_unlock(&mdsc->mutex);
4353 
4354 		mutex_lock(&s->s_mutex);
4355 		if (renew_caps)
4356 			send_renew_caps(mdsc, s);
4357 		else
4358 			ceph_con_keepalive(&s->s_con);
4359 		if (s->s_state == CEPH_MDS_SESSION_OPEN ||
4360 		    s->s_state == CEPH_MDS_SESSION_HUNG)
4361 			ceph_send_cap_releases(mdsc, s);
4362 		mutex_unlock(&s->s_mutex);
4363 		ceph_put_mds_session(s);
4364 
4365 		mutex_lock(&mdsc->mutex);
4366 	}
4367 	mutex_unlock(&mdsc->mutex);
4368 
4369 	ceph_check_delayed_caps(mdsc);
4370 
4371 	ceph_queue_cap_reclaim_work(mdsc);
4372 
4373 	ceph_trim_snapid_map(mdsc);
4374 
4375 	maybe_recover_session(mdsc);
4376 
4377 	schedule_delayed(mdsc);
4378 }
4379 
4380 int ceph_mdsc_init(struct ceph_fs_client *fsc)
4381 
4382 {
4383 	struct ceph_mds_client *mdsc;
4384 	int err;
4385 
4386 	mdsc = kzalloc(sizeof(struct ceph_mds_client), GFP_NOFS);
4387 	if (!mdsc)
4388 		return -ENOMEM;
4389 	mdsc->fsc = fsc;
4390 	mutex_init(&mdsc->mutex);
4391 	mdsc->mdsmap = kzalloc(sizeof(*mdsc->mdsmap), GFP_NOFS);
4392 	if (!mdsc->mdsmap) {
4393 		err = -ENOMEM;
4394 		goto err_mdsc;
4395 	}
4396 
4397 	fsc->mdsc = mdsc;
4398 	init_completion(&mdsc->safe_umount_waiters);
4399 	init_waitqueue_head(&mdsc->session_close_wq);
4400 	INIT_LIST_HEAD(&mdsc->waiting_for_map);
4401 	mdsc->sessions = NULL;
4402 	atomic_set(&mdsc->num_sessions, 0);
4403 	mdsc->max_sessions = 0;
4404 	mdsc->stopping = 0;
4405 	atomic64_set(&mdsc->quotarealms_count, 0);
4406 	mdsc->quotarealms_inodes = RB_ROOT;
4407 	mutex_init(&mdsc->quotarealms_inodes_mutex);
4408 	mdsc->last_snap_seq = 0;
4409 	init_rwsem(&mdsc->snap_rwsem);
4410 	mdsc->snap_realms = RB_ROOT;
4411 	INIT_LIST_HEAD(&mdsc->snap_empty);
4412 	mdsc->num_snap_realms = 0;
4413 	spin_lock_init(&mdsc->snap_empty_lock);
4414 	mdsc->last_tid = 0;
4415 	mdsc->oldest_tid = 0;
4416 	mdsc->request_tree = RB_ROOT;
4417 	INIT_DELAYED_WORK(&mdsc->delayed_work, delayed_work);
4418 	mdsc->last_renew_caps = jiffies;
4419 	INIT_LIST_HEAD(&mdsc->cap_delay_list);
4420 	INIT_LIST_HEAD(&mdsc->cap_wait_list);
4421 	spin_lock_init(&mdsc->cap_delay_lock);
4422 	INIT_LIST_HEAD(&mdsc->snap_flush_list);
4423 	spin_lock_init(&mdsc->snap_flush_lock);
4424 	mdsc->last_cap_flush_tid = 1;
4425 	INIT_LIST_HEAD(&mdsc->cap_flush_list);
4426 	INIT_LIST_HEAD(&mdsc->cap_dirty_migrating);
4427 	mdsc->num_cap_flushing = 0;
4428 	spin_lock_init(&mdsc->cap_dirty_lock);
4429 	init_waitqueue_head(&mdsc->cap_flushing_wq);
4430 	INIT_WORK(&mdsc->cap_reclaim_work, ceph_cap_reclaim_work);
4431 	atomic_set(&mdsc->cap_reclaim_pending, 0);
4432 	err = ceph_metric_init(&mdsc->metric);
4433 	if (err)
4434 		goto err_mdsmap;
4435 
4436 	spin_lock_init(&mdsc->dentry_list_lock);
4437 	INIT_LIST_HEAD(&mdsc->dentry_leases);
4438 	INIT_LIST_HEAD(&mdsc->dentry_dir_leases);
4439 
4440 	ceph_caps_init(mdsc);
4441 	ceph_adjust_caps_max_min(mdsc, fsc->mount_options);
4442 
4443 	spin_lock_init(&mdsc->snapid_map_lock);
4444 	mdsc->snapid_map_tree = RB_ROOT;
4445 	INIT_LIST_HEAD(&mdsc->snapid_map_lru);
4446 
4447 	init_rwsem(&mdsc->pool_perm_rwsem);
4448 	mdsc->pool_perm_tree = RB_ROOT;
4449 
4450 	strscpy(mdsc->nodename, utsname()->nodename,
4451 		sizeof(mdsc->nodename));
4452 	return 0;
4453 
4454 err_mdsmap:
4455 	kfree(mdsc->mdsmap);
4456 err_mdsc:
4457 	kfree(mdsc);
4458 	return err;
4459 }
4460 
4461 /*
4462  * Wait for safe replies on open mds requests.  If we time out, drop
4463  * all requests from the tree to avoid dangling dentry refs.
4464  */
4465 static void wait_requests(struct ceph_mds_client *mdsc)
4466 {
4467 	struct ceph_options *opts = mdsc->fsc->client->options;
4468 	struct ceph_mds_request *req;
4469 
4470 	mutex_lock(&mdsc->mutex);
4471 	if (__get_oldest_req(mdsc)) {
4472 		mutex_unlock(&mdsc->mutex);
4473 
4474 		dout("wait_requests waiting for requests\n");
4475 		wait_for_completion_timeout(&mdsc->safe_umount_waiters,
4476 				    ceph_timeout_jiffies(opts->mount_timeout));
4477 
4478 		/* tear down remaining requests */
4479 		mutex_lock(&mdsc->mutex);
4480 		while ((req = __get_oldest_req(mdsc))) {
4481 			dout("wait_requests timed out on tid %llu\n",
4482 			     req->r_tid);
4483 			list_del_init(&req->r_wait);
4484 			__unregister_request(mdsc, req);
4485 		}
4486 	}
4487 	mutex_unlock(&mdsc->mutex);
4488 	dout("wait_requests done\n");
4489 }
4490 
4491 /*
4492  * called before mount is ro, and before dentries are torn down.
4493  * (hmm, does this still race with new lookups?)
4494  */
4495 void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc)
4496 {
4497 	dout("pre_umount\n");
4498 	mdsc->stopping = 1;
4499 
4500 	lock_unlock_sessions(mdsc);
4501 	ceph_flush_dirty_caps(mdsc);
4502 	wait_requests(mdsc);
4503 
4504 	/*
4505 	 * wait for reply handlers to drop their request refs and
4506 	 * their inode/dcache refs
4507 	 */
4508 	ceph_msgr_flush();
4509 
4510 	ceph_cleanup_quotarealms_inodes(mdsc);
4511 }
4512 
4513 /*
4514  * wait for all write mds requests to flush.
4515  */
4516 static void wait_unsafe_requests(struct ceph_mds_client *mdsc, u64 want_tid)
4517 {
4518 	struct ceph_mds_request *req = NULL, *nextreq;
4519 	struct rb_node *n;
4520 
4521 	mutex_lock(&mdsc->mutex);
4522 	dout("wait_unsafe_requests want %lld\n", want_tid);
4523 restart:
4524 	req = __get_oldest_req(mdsc);
4525 	while (req && req->r_tid <= want_tid) {
4526 		/* find next request */
4527 		n = rb_next(&req->r_node);
4528 		if (n)
4529 			nextreq = rb_entry(n, struct ceph_mds_request, r_node);
4530 		else
4531 			nextreq = NULL;
4532 		if (req->r_op != CEPH_MDS_OP_SETFILELOCK &&
4533 		    (req->r_op & CEPH_MDS_OP_WRITE)) {
4534 			/* write op */
4535 			ceph_mdsc_get_request(req);
4536 			if (nextreq)
4537 				ceph_mdsc_get_request(nextreq);
4538 			mutex_unlock(&mdsc->mutex);
4539 			dout("wait_unsafe_requests  wait on %llu (want %llu)\n",
4540 			     req->r_tid, want_tid);
4541 			wait_for_completion(&req->r_safe_completion);
4542 			mutex_lock(&mdsc->mutex);
4543 			ceph_mdsc_put_request(req);
4544 			if (!nextreq)
4545 				break;  /* next dne before, so we're done! */
4546 			if (RB_EMPTY_NODE(&nextreq->r_node)) {
4547 				/* next request was removed from tree */
4548 				ceph_mdsc_put_request(nextreq);
4549 				goto restart;
4550 			}
4551 			ceph_mdsc_put_request(nextreq);  /* won't go away */
4552 		}
4553 		req = nextreq;
4554 	}
4555 	mutex_unlock(&mdsc->mutex);
4556 	dout("wait_unsafe_requests done\n");
4557 }
4558 
4559 void ceph_mdsc_sync(struct ceph_mds_client *mdsc)
4560 {
4561 	u64 want_tid, want_flush;
4562 
4563 	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_SHUTDOWN)
4564 		return;
4565 
4566 	dout("sync\n");
4567 	mutex_lock(&mdsc->mutex);
4568 	want_tid = mdsc->last_tid;
4569 	mutex_unlock(&mdsc->mutex);
4570 
4571 	ceph_flush_dirty_caps(mdsc);
4572 	spin_lock(&mdsc->cap_dirty_lock);
4573 	want_flush = mdsc->last_cap_flush_tid;
4574 	if (!list_empty(&mdsc->cap_flush_list)) {
4575 		struct ceph_cap_flush *cf =
4576 			list_last_entry(&mdsc->cap_flush_list,
4577 					struct ceph_cap_flush, g_list);
4578 		cf->wake = true;
4579 	}
4580 	spin_unlock(&mdsc->cap_dirty_lock);
4581 
4582 	dout("sync want tid %lld flush_seq %lld\n",
4583 	     want_tid, want_flush);
4584 
4585 	wait_unsafe_requests(mdsc, want_tid);
4586 	wait_caps_flush(mdsc, want_flush);
4587 }
4588 
4589 /*
4590  * true if all sessions are closed, or we force unmount
4591  */
4592 static bool done_closing_sessions(struct ceph_mds_client *mdsc, int skipped)
4593 {
4594 	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_SHUTDOWN)
4595 		return true;
4596 	return atomic_read(&mdsc->num_sessions) <= skipped;
4597 }
4598 
4599 /*
4600  * called after sb is ro.
4601  */
4602 void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc)
4603 {
4604 	struct ceph_options *opts = mdsc->fsc->client->options;
4605 	struct ceph_mds_session *session;
4606 	int i;
4607 	int skipped = 0;
4608 
4609 	dout("close_sessions\n");
4610 
4611 	/* close sessions */
4612 	mutex_lock(&mdsc->mutex);
4613 	for (i = 0; i < mdsc->max_sessions; i++) {
4614 		session = __ceph_lookup_mds_session(mdsc, i);
4615 		if (!session)
4616 			continue;
4617 		mutex_unlock(&mdsc->mutex);
4618 		mutex_lock(&session->s_mutex);
4619 		if (__close_session(mdsc, session) <= 0)
4620 			skipped++;
4621 		mutex_unlock(&session->s_mutex);
4622 		ceph_put_mds_session(session);
4623 		mutex_lock(&mdsc->mutex);
4624 	}
4625 	mutex_unlock(&mdsc->mutex);
4626 
4627 	dout("waiting for sessions to close\n");
4628 	wait_event_timeout(mdsc->session_close_wq,
4629 			   done_closing_sessions(mdsc, skipped),
4630 			   ceph_timeout_jiffies(opts->mount_timeout));
4631 
4632 	/* tear down remaining sessions */
4633 	mutex_lock(&mdsc->mutex);
4634 	for (i = 0; i < mdsc->max_sessions; i++) {
4635 		if (mdsc->sessions[i]) {
4636 			session = ceph_get_mds_session(mdsc->sessions[i]);
4637 			__unregister_session(mdsc, session);
4638 			mutex_unlock(&mdsc->mutex);
4639 			mutex_lock(&session->s_mutex);
4640 			remove_session_caps(session);
4641 			mutex_unlock(&session->s_mutex);
4642 			ceph_put_mds_session(session);
4643 			mutex_lock(&mdsc->mutex);
4644 		}
4645 	}
4646 	WARN_ON(!list_empty(&mdsc->cap_delay_list));
4647 	mutex_unlock(&mdsc->mutex);
4648 
4649 	ceph_cleanup_snapid_map(mdsc);
4650 	ceph_cleanup_empty_realms(mdsc);
4651 
4652 	cancel_work_sync(&mdsc->cap_reclaim_work);
4653 	cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
4654 
4655 	dout("stopped\n");
4656 }
4657 
4658 void ceph_mdsc_force_umount(struct ceph_mds_client *mdsc)
4659 {
4660 	struct ceph_mds_session *session;
4661 	int mds;
4662 
4663 	dout("force umount\n");
4664 
4665 	mutex_lock(&mdsc->mutex);
4666 	for (mds = 0; mds < mdsc->max_sessions; mds++) {
4667 		session = __ceph_lookup_mds_session(mdsc, mds);
4668 		if (!session)
4669 			continue;
4670 
4671 		if (session->s_state == CEPH_MDS_SESSION_REJECTED)
4672 			__unregister_session(mdsc, session);
4673 		__wake_requests(mdsc, &session->s_waiting);
4674 		mutex_unlock(&mdsc->mutex);
4675 
4676 		mutex_lock(&session->s_mutex);
4677 		__close_session(mdsc, session);
4678 		if (session->s_state == CEPH_MDS_SESSION_CLOSING) {
4679 			cleanup_session_requests(mdsc, session);
4680 			remove_session_caps(session);
4681 		}
4682 		mutex_unlock(&session->s_mutex);
4683 		ceph_put_mds_session(session);
4684 
4685 		mutex_lock(&mdsc->mutex);
4686 		kick_requests(mdsc, mds);
4687 	}
4688 	__wake_requests(mdsc, &mdsc->waiting_for_map);
4689 	mutex_unlock(&mdsc->mutex);
4690 }
4691 
4692 static void ceph_mdsc_stop(struct ceph_mds_client *mdsc)
4693 {
4694 	dout("stop\n");
4695 	/*
4696 	 * Make sure the delayed work stopped before releasing
4697 	 * the resources.
4698 	 *
4699 	 * Because the cancel_delayed_work_sync() will only
4700 	 * guarantee that the work finishes executing. But the
4701 	 * delayed work will re-arm itself again after that.
4702 	 */
4703 	flush_delayed_work(&mdsc->delayed_work);
4704 
4705 	if (mdsc->mdsmap)
4706 		ceph_mdsmap_destroy(mdsc->mdsmap);
4707 	kfree(mdsc->sessions);
4708 	ceph_caps_finalize(mdsc);
4709 	ceph_pool_perm_destroy(mdsc);
4710 }
4711 
4712 void ceph_mdsc_destroy(struct ceph_fs_client *fsc)
4713 {
4714 	struct ceph_mds_client *mdsc = fsc->mdsc;
4715 	dout("mdsc_destroy %p\n", mdsc);
4716 
4717 	if (!mdsc)
4718 		return;
4719 
4720 	/* flush out any connection work with references to us */
4721 	ceph_msgr_flush();
4722 
4723 	ceph_mdsc_stop(mdsc);
4724 
4725 	ceph_metric_destroy(&mdsc->metric);
4726 
4727 	fsc->mdsc = NULL;
4728 	kfree(mdsc);
4729 	dout("mdsc_destroy %p done\n", mdsc);
4730 }
4731 
4732 void ceph_mdsc_handle_fsmap(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
4733 {
4734 	struct ceph_fs_client *fsc = mdsc->fsc;
4735 	const char *mds_namespace = fsc->mount_options->mds_namespace;
4736 	void *p = msg->front.iov_base;
4737 	void *end = p + msg->front.iov_len;
4738 	u32 epoch;
4739 	u32 map_len;
4740 	u32 num_fs;
4741 	u32 mount_fscid = (u32)-1;
4742 	u8 struct_v, struct_cv;
4743 	int err = -EINVAL;
4744 
4745 	ceph_decode_need(&p, end, sizeof(u32), bad);
4746 	epoch = ceph_decode_32(&p);
4747 
4748 	dout("handle_fsmap epoch %u\n", epoch);
4749 
4750 	ceph_decode_need(&p, end, 2 + sizeof(u32), bad);
4751 	struct_v = ceph_decode_8(&p);
4752 	struct_cv = ceph_decode_8(&p);
4753 	map_len = ceph_decode_32(&p);
4754 
4755 	ceph_decode_need(&p, end, sizeof(u32) * 3, bad);
4756 	p += sizeof(u32) * 2; /* skip epoch and legacy_client_fscid */
4757 
4758 	num_fs = ceph_decode_32(&p);
4759 	while (num_fs-- > 0) {
4760 		void *info_p, *info_end;
4761 		u32 info_len;
4762 		u8 info_v, info_cv;
4763 		u32 fscid, namelen;
4764 
4765 		ceph_decode_need(&p, end, 2 + sizeof(u32), bad);
4766 		info_v = ceph_decode_8(&p);
4767 		info_cv = ceph_decode_8(&p);
4768 		info_len = ceph_decode_32(&p);
4769 		ceph_decode_need(&p, end, info_len, bad);
4770 		info_p = p;
4771 		info_end = p + info_len;
4772 		p = info_end;
4773 
4774 		ceph_decode_need(&info_p, info_end, sizeof(u32) * 2, bad);
4775 		fscid = ceph_decode_32(&info_p);
4776 		namelen = ceph_decode_32(&info_p);
4777 		ceph_decode_need(&info_p, info_end, namelen, bad);
4778 
4779 		if (mds_namespace &&
4780 		    strlen(mds_namespace) == namelen &&
4781 		    !strncmp(mds_namespace, (char *)info_p, namelen)) {
4782 			mount_fscid = fscid;
4783 			break;
4784 		}
4785 	}
4786 
4787 	ceph_monc_got_map(&fsc->client->monc, CEPH_SUB_FSMAP, epoch);
4788 	if (mount_fscid != (u32)-1) {
4789 		fsc->client->monc.fs_cluster_id = mount_fscid;
4790 		ceph_monc_want_map(&fsc->client->monc, CEPH_SUB_MDSMAP,
4791 				   0, true);
4792 		ceph_monc_renew_subs(&fsc->client->monc);
4793 	} else {
4794 		err = -ENOENT;
4795 		goto err_out;
4796 	}
4797 	return;
4798 
4799 bad:
4800 	pr_err("error decoding fsmap\n");
4801 err_out:
4802 	mutex_lock(&mdsc->mutex);
4803 	mdsc->mdsmap_err = err;
4804 	__wake_requests(mdsc, &mdsc->waiting_for_map);
4805 	mutex_unlock(&mdsc->mutex);
4806 }
4807 
4808 /*
4809  * handle mds map update.
4810  */
4811 void ceph_mdsc_handle_mdsmap(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
4812 {
4813 	u32 epoch;
4814 	u32 maplen;
4815 	void *p = msg->front.iov_base;
4816 	void *end = p + msg->front.iov_len;
4817 	struct ceph_mdsmap *newmap, *oldmap;
4818 	struct ceph_fsid fsid;
4819 	int err = -EINVAL;
4820 
4821 	ceph_decode_need(&p, end, sizeof(fsid)+2*sizeof(u32), bad);
4822 	ceph_decode_copy(&p, &fsid, sizeof(fsid));
4823 	if (ceph_check_fsid(mdsc->fsc->client, &fsid) < 0)
4824 		return;
4825 	epoch = ceph_decode_32(&p);
4826 	maplen = ceph_decode_32(&p);
4827 	dout("handle_map epoch %u len %d\n", epoch, (int)maplen);
4828 
4829 	/* do we need it? */
4830 	mutex_lock(&mdsc->mutex);
4831 	if (mdsc->mdsmap && epoch <= mdsc->mdsmap->m_epoch) {
4832 		dout("handle_map epoch %u <= our %u\n",
4833 		     epoch, mdsc->mdsmap->m_epoch);
4834 		mutex_unlock(&mdsc->mutex);
4835 		return;
4836 	}
4837 
4838 	newmap = ceph_mdsmap_decode(&p, end);
4839 	if (IS_ERR(newmap)) {
4840 		err = PTR_ERR(newmap);
4841 		goto bad_unlock;
4842 	}
4843 
4844 	/* swap into place */
4845 	if (mdsc->mdsmap) {
4846 		oldmap = mdsc->mdsmap;
4847 		mdsc->mdsmap = newmap;
4848 		check_new_map(mdsc, newmap, oldmap);
4849 		ceph_mdsmap_destroy(oldmap);
4850 	} else {
4851 		mdsc->mdsmap = newmap;  /* first mds map */
4852 	}
4853 	mdsc->fsc->max_file_size = min((loff_t)mdsc->mdsmap->m_max_file_size,
4854 					MAX_LFS_FILESIZE);
4855 
4856 	__wake_requests(mdsc, &mdsc->waiting_for_map);
4857 	ceph_monc_got_map(&mdsc->fsc->client->monc, CEPH_SUB_MDSMAP,
4858 			  mdsc->mdsmap->m_epoch);
4859 
4860 	mutex_unlock(&mdsc->mutex);
4861 	schedule_delayed(mdsc);
4862 	return;
4863 
4864 bad_unlock:
4865 	mutex_unlock(&mdsc->mutex);
4866 bad:
4867 	pr_err("error decoding mdsmap %d\n", err);
4868 	return;
4869 }
4870 
4871 static struct ceph_connection *con_get(struct ceph_connection *con)
4872 {
4873 	struct ceph_mds_session *s = con->private;
4874 
4875 	if (ceph_get_mds_session(s))
4876 		return con;
4877 	return NULL;
4878 }
4879 
4880 static void con_put(struct ceph_connection *con)
4881 {
4882 	struct ceph_mds_session *s = con->private;
4883 
4884 	ceph_put_mds_session(s);
4885 }
4886 
4887 /*
4888  * if the client is unresponsive for long enough, the mds will kill
4889  * the session entirely.
4890  */
4891 static void peer_reset(struct ceph_connection *con)
4892 {
4893 	struct ceph_mds_session *s = con->private;
4894 	struct ceph_mds_client *mdsc = s->s_mdsc;
4895 
4896 	pr_warn("mds%d closed our session\n", s->s_mds);
4897 	send_mds_reconnect(mdsc, s);
4898 }
4899 
4900 static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
4901 {
4902 	struct ceph_mds_session *s = con->private;
4903 	struct ceph_mds_client *mdsc = s->s_mdsc;
4904 	int type = le16_to_cpu(msg->hdr.type);
4905 
4906 	mutex_lock(&mdsc->mutex);
4907 	if (__verify_registered_session(mdsc, s) < 0) {
4908 		mutex_unlock(&mdsc->mutex);
4909 		goto out;
4910 	}
4911 	mutex_unlock(&mdsc->mutex);
4912 
4913 	switch (type) {
4914 	case CEPH_MSG_MDS_MAP:
4915 		ceph_mdsc_handle_mdsmap(mdsc, msg);
4916 		break;
4917 	case CEPH_MSG_FS_MAP_USER:
4918 		ceph_mdsc_handle_fsmap(mdsc, msg);
4919 		break;
4920 	case CEPH_MSG_CLIENT_SESSION:
4921 		handle_session(s, msg);
4922 		break;
4923 	case CEPH_MSG_CLIENT_REPLY:
4924 		handle_reply(s, msg);
4925 		break;
4926 	case CEPH_MSG_CLIENT_REQUEST_FORWARD:
4927 		handle_forward(mdsc, s, msg);
4928 		break;
4929 	case CEPH_MSG_CLIENT_CAPS:
4930 		ceph_handle_caps(s, msg);
4931 		break;
4932 	case CEPH_MSG_CLIENT_SNAP:
4933 		ceph_handle_snap(mdsc, s, msg);
4934 		break;
4935 	case CEPH_MSG_CLIENT_LEASE:
4936 		handle_lease(mdsc, s, msg);
4937 		break;
4938 	case CEPH_MSG_CLIENT_QUOTA:
4939 		ceph_handle_quota(mdsc, s, msg);
4940 		break;
4941 
4942 	default:
4943 		pr_err("received unknown message type %d %s\n", type,
4944 		       ceph_msg_type_name(type));
4945 	}
4946 out:
4947 	ceph_msg_put(msg);
4948 }
4949 
4950 /*
4951  * authentication
4952  */
4953 
4954 /*
4955  * Note: returned pointer is the address of a structure that's
4956  * managed separately.  Caller must *not* attempt to free it.
4957  */
4958 static struct ceph_auth_handshake *get_authorizer(struct ceph_connection *con,
4959 					int *proto, int force_new)
4960 {
4961 	struct ceph_mds_session *s = con->private;
4962 	struct ceph_mds_client *mdsc = s->s_mdsc;
4963 	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
4964 	struct ceph_auth_handshake *auth = &s->s_auth;
4965 
4966 	if (force_new && auth->authorizer) {
4967 		ceph_auth_destroy_authorizer(auth->authorizer);
4968 		auth->authorizer = NULL;
4969 	}
4970 	if (!auth->authorizer) {
4971 		int ret = ceph_auth_create_authorizer(ac, CEPH_ENTITY_TYPE_MDS,
4972 						      auth);
4973 		if (ret)
4974 			return ERR_PTR(ret);
4975 	} else {
4976 		int ret = ceph_auth_update_authorizer(ac, CEPH_ENTITY_TYPE_MDS,
4977 						      auth);
4978 		if (ret)
4979 			return ERR_PTR(ret);
4980 	}
4981 	*proto = ac->protocol;
4982 
4983 	return auth;
4984 }
4985 
4986 static int add_authorizer_challenge(struct ceph_connection *con,
4987 				    void *challenge_buf, int challenge_buf_len)
4988 {
4989 	struct ceph_mds_session *s = con->private;
4990 	struct ceph_mds_client *mdsc = s->s_mdsc;
4991 	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
4992 
4993 	return ceph_auth_add_authorizer_challenge(ac, s->s_auth.authorizer,
4994 					    challenge_buf, challenge_buf_len);
4995 }
4996 
4997 static int verify_authorizer_reply(struct ceph_connection *con)
4998 {
4999 	struct ceph_mds_session *s = con->private;
5000 	struct ceph_mds_client *mdsc = s->s_mdsc;
5001 	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
5002 
5003 	return ceph_auth_verify_authorizer_reply(ac, s->s_auth.authorizer);
5004 }
5005 
5006 static int invalidate_authorizer(struct ceph_connection *con)
5007 {
5008 	struct ceph_mds_session *s = con->private;
5009 	struct ceph_mds_client *mdsc = s->s_mdsc;
5010 	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
5011 
5012 	ceph_auth_invalidate_authorizer(ac, CEPH_ENTITY_TYPE_MDS);
5013 
5014 	return ceph_monc_validate_auth(&mdsc->fsc->client->monc);
5015 }
5016 
5017 static struct ceph_msg *mds_alloc_msg(struct ceph_connection *con,
5018 				struct ceph_msg_header *hdr, int *skip)
5019 {
5020 	struct ceph_msg *msg;
5021 	int type = (int) le16_to_cpu(hdr->type);
5022 	int front_len = (int) le32_to_cpu(hdr->front_len);
5023 
5024 	if (con->in_msg)
5025 		return con->in_msg;
5026 
5027 	*skip = 0;
5028 	msg = ceph_msg_new(type, front_len, GFP_NOFS, false);
5029 	if (!msg) {
5030 		pr_err("unable to allocate msg type %d len %d\n",
5031 		       type, front_len);
5032 		return NULL;
5033 	}
5034 
5035 	return msg;
5036 }
5037 
5038 static int mds_sign_message(struct ceph_msg *msg)
5039 {
5040        struct ceph_mds_session *s = msg->con->private;
5041        struct ceph_auth_handshake *auth = &s->s_auth;
5042 
5043        return ceph_auth_sign_message(auth, msg);
5044 }
5045 
5046 static int mds_check_message_signature(struct ceph_msg *msg)
5047 {
5048        struct ceph_mds_session *s = msg->con->private;
5049        struct ceph_auth_handshake *auth = &s->s_auth;
5050 
5051        return ceph_auth_check_message_signature(auth, msg);
5052 }
5053 
5054 static const struct ceph_connection_operations mds_con_ops = {
5055 	.get = con_get,
5056 	.put = con_put,
5057 	.dispatch = dispatch,
5058 	.get_authorizer = get_authorizer,
5059 	.add_authorizer_challenge = add_authorizer_challenge,
5060 	.verify_authorizer_reply = verify_authorizer_reply,
5061 	.invalidate_authorizer = invalidate_authorizer,
5062 	.peer_reset = peer_reset,
5063 	.alloc_msg = mds_alloc_msg,
5064 	.sign_message = mds_sign_message,
5065 	.check_message_signature = mds_check_message_signature,
5066 };
5067 
5068 /* eof */
5069