xref: /openbmc/linux/fs/ceph/mds_client.c (revision d63670d2)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/ceph/ceph_debug.h>
3 
4 #include <linux/fs.h>
5 #include <linux/wait.h>
6 #include <linux/slab.h>
7 #include <linux/gfp.h>
8 #include <linux/sched.h>
9 #include <linux/debugfs.h>
10 #include <linux/seq_file.h>
11 #include <linux/ratelimit.h>
12 #include <linux/bits.h>
13 #include <linux/ktime.h>
14 #include <linux/bitmap.h>
15 
16 #include "super.h"
17 #include "mds_client.h"
18 
19 #include <linux/ceph/ceph_features.h>
20 #include <linux/ceph/messenger.h>
21 #include <linux/ceph/decode.h>
22 #include <linux/ceph/pagelist.h>
23 #include <linux/ceph/auth.h>
24 #include <linux/ceph/debugfs.h>
25 
26 #define RECONNECT_MAX_SIZE (INT_MAX - PAGE_SIZE)
27 
28 /*
29  * A cluster of MDS (metadata server) daemons is responsible for
30  * managing the file system namespace (the directory hierarchy and
31  * inodes) and for coordinating shared access to storage.  Metadata is
32  * partitioning hierarchically across a number of servers, and that
33  * partition varies over time as the cluster adjusts the distribution
34  * in order to balance load.
35  *
36  * The MDS client is primarily responsible to managing synchronous
37  * metadata requests for operations like open, unlink, and so forth.
38  * If there is a MDS failure, we find out about it when we (possibly
39  * request and) receive a new MDS map, and can resubmit affected
40  * requests.
41  *
42  * For the most part, though, we take advantage of a lossless
43  * communications channel to the MDS, and do not need to worry about
44  * timing out or resubmitting requests.
45  *
46  * We maintain a stateful "session" with each MDS we interact with.
47  * Within each session, we sent periodic heartbeat messages to ensure
48  * any capabilities or leases we have been issues remain valid.  If
49  * the session times out and goes stale, our leases and capabilities
50  * are no longer valid.
51  */
52 
53 struct ceph_reconnect_state {
54 	struct ceph_mds_session *session;
55 	int nr_caps, nr_realms;
56 	struct ceph_pagelist *pagelist;
57 	unsigned msg_version;
58 	bool allow_multi;
59 };
60 
61 static void __wake_requests(struct ceph_mds_client *mdsc,
62 			    struct list_head *head);
63 static void ceph_cap_release_work(struct work_struct *work);
64 static void ceph_cap_reclaim_work(struct work_struct *work);
65 
66 static const struct ceph_connection_operations mds_con_ops;
67 
68 
69 /*
70  * mds reply parsing
71  */
72 
73 static int parse_reply_info_quota(void **p, void *end,
74 				  struct ceph_mds_reply_info_in *info)
75 {
76 	u8 struct_v, struct_compat;
77 	u32 struct_len;
78 
79 	ceph_decode_8_safe(p, end, struct_v, bad);
80 	ceph_decode_8_safe(p, end, struct_compat, bad);
81 	/* struct_v is expected to be >= 1. we only
82 	 * understand encoding with struct_compat == 1. */
83 	if (!struct_v || struct_compat != 1)
84 		goto bad;
85 	ceph_decode_32_safe(p, end, struct_len, bad);
86 	ceph_decode_need(p, end, struct_len, bad);
87 	end = *p + struct_len;
88 	ceph_decode_64_safe(p, end, info->max_bytes, bad);
89 	ceph_decode_64_safe(p, end, info->max_files, bad);
90 	*p = end;
91 	return 0;
92 bad:
93 	return -EIO;
94 }
95 
96 /*
97  * parse individual inode info
98  */
99 static int parse_reply_info_in(void **p, void *end,
100 			       struct ceph_mds_reply_info_in *info,
101 			       u64 features)
102 {
103 	int err = 0;
104 	u8 struct_v = 0;
105 
106 	if (features == (u64)-1) {
107 		u32 struct_len;
108 		u8 struct_compat;
109 		ceph_decode_8_safe(p, end, struct_v, bad);
110 		ceph_decode_8_safe(p, end, struct_compat, bad);
111 		/* struct_v is expected to be >= 1. we only understand
112 		 * encoding with struct_compat == 1. */
113 		if (!struct_v || struct_compat != 1)
114 			goto bad;
115 		ceph_decode_32_safe(p, end, struct_len, bad);
116 		ceph_decode_need(p, end, struct_len, bad);
117 		end = *p + struct_len;
118 	}
119 
120 	ceph_decode_need(p, end, sizeof(struct ceph_mds_reply_inode), bad);
121 	info->in = *p;
122 	*p += sizeof(struct ceph_mds_reply_inode) +
123 		sizeof(*info->in->fragtree.splits) *
124 		le32_to_cpu(info->in->fragtree.nsplits);
125 
126 	ceph_decode_32_safe(p, end, info->symlink_len, bad);
127 	ceph_decode_need(p, end, info->symlink_len, bad);
128 	info->symlink = *p;
129 	*p += info->symlink_len;
130 
131 	ceph_decode_copy_safe(p, end, &info->dir_layout,
132 			      sizeof(info->dir_layout), bad);
133 	ceph_decode_32_safe(p, end, info->xattr_len, bad);
134 	ceph_decode_need(p, end, info->xattr_len, bad);
135 	info->xattr_data = *p;
136 	*p += info->xattr_len;
137 
138 	if (features == (u64)-1) {
139 		/* inline data */
140 		ceph_decode_64_safe(p, end, info->inline_version, bad);
141 		ceph_decode_32_safe(p, end, info->inline_len, bad);
142 		ceph_decode_need(p, end, info->inline_len, bad);
143 		info->inline_data = *p;
144 		*p += info->inline_len;
145 		/* quota */
146 		err = parse_reply_info_quota(p, end, info);
147 		if (err < 0)
148 			goto out_bad;
149 		/* pool namespace */
150 		ceph_decode_32_safe(p, end, info->pool_ns_len, bad);
151 		if (info->pool_ns_len > 0) {
152 			ceph_decode_need(p, end, info->pool_ns_len, bad);
153 			info->pool_ns_data = *p;
154 			*p += info->pool_ns_len;
155 		}
156 
157 		/* btime */
158 		ceph_decode_need(p, end, sizeof(info->btime), bad);
159 		ceph_decode_copy(p, &info->btime, sizeof(info->btime));
160 
161 		/* change attribute */
162 		ceph_decode_64_safe(p, end, info->change_attr, bad);
163 
164 		/* dir pin */
165 		if (struct_v >= 2) {
166 			ceph_decode_32_safe(p, end, info->dir_pin, bad);
167 		} else {
168 			info->dir_pin = -ENODATA;
169 		}
170 
171 		/* snapshot birth time, remains zero for v<=2 */
172 		if (struct_v >= 3) {
173 			ceph_decode_need(p, end, sizeof(info->snap_btime), bad);
174 			ceph_decode_copy(p, &info->snap_btime,
175 					 sizeof(info->snap_btime));
176 		} else {
177 			memset(&info->snap_btime, 0, sizeof(info->snap_btime));
178 		}
179 
180 		/* snapshot count, remains zero for v<=3 */
181 		if (struct_v >= 4) {
182 			ceph_decode_64_safe(p, end, info->rsnaps, bad);
183 		} else {
184 			info->rsnaps = 0;
185 		}
186 
187 		*p = end;
188 	} else {
189 		if (features & CEPH_FEATURE_MDS_INLINE_DATA) {
190 			ceph_decode_64_safe(p, end, info->inline_version, bad);
191 			ceph_decode_32_safe(p, end, info->inline_len, bad);
192 			ceph_decode_need(p, end, info->inline_len, bad);
193 			info->inline_data = *p;
194 			*p += info->inline_len;
195 		} else
196 			info->inline_version = CEPH_INLINE_NONE;
197 
198 		if (features & CEPH_FEATURE_MDS_QUOTA) {
199 			err = parse_reply_info_quota(p, end, info);
200 			if (err < 0)
201 				goto out_bad;
202 		} else {
203 			info->max_bytes = 0;
204 			info->max_files = 0;
205 		}
206 
207 		info->pool_ns_len = 0;
208 		info->pool_ns_data = NULL;
209 		if (features & CEPH_FEATURE_FS_FILE_LAYOUT_V2) {
210 			ceph_decode_32_safe(p, end, info->pool_ns_len, bad);
211 			if (info->pool_ns_len > 0) {
212 				ceph_decode_need(p, end, info->pool_ns_len, bad);
213 				info->pool_ns_data = *p;
214 				*p += info->pool_ns_len;
215 			}
216 		}
217 
218 		if (features & CEPH_FEATURE_FS_BTIME) {
219 			ceph_decode_need(p, end, sizeof(info->btime), bad);
220 			ceph_decode_copy(p, &info->btime, sizeof(info->btime));
221 			ceph_decode_64_safe(p, end, info->change_attr, bad);
222 		}
223 
224 		info->dir_pin = -ENODATA;
225 		/* info->snap_btime and info->rsnaps remain zero */
226 	}
227 	return 0;
228 bad:
229 	err = -EIO;
230 out_bad:
231 	return err;
232 }
233 
234 static int parse_reply_info_dir(void **p, void *end,
235 				struct ceph_mds_reply_dirfrag **dirfrag,
236 				u64 features)
237 {
238 	if (features == (u64)-1) {
239 		u8 struct_v, struct_compat;
240 		u32 struct_len;
241 		ceph_decode_8_safe(p, end, struct_v, bad);
242 		ceph_decode_8_safe(p, end, struct_compat, bad);
243 		/* struct_v is expected to be >= 1. we only understand
244 		 * encoding whose struct_compat == 1. */
245 		if (!struct_v || struct_compat != 1)
246 			goto bad;
247 		ceph_decode_32_safe(p, end, struct_len, bad);
248 		ceph_decode_need(p, end, struct_len, bad);
249 		end = *p + struct_len;
250 	}
251 
252 	ceph_decode_need(p, end, sizeof(**dirfrag), bad);
253 	*dirfrag = *p;
254 	*p += sizeof(**dirfrag) + sizeof(u32) * le32_to_cpu((*dirfrag)->ndist);
255 	if (unlikely(*p > end))
256 		goto bad;
257 	if (features == (u64)-1)
258 		*p = end;
259 	return 0;
260 bad:
261 	return -EIO;
262 }
263 
264 static int parse_reply_info_lease(void **p, void *end,
265 				  struct ceph_mds_reply_lease **lease,
266 				  u64 features)
267 {
268 	if (features == (u64)-1) {
269 		u8 struct_v, struct_compat;
270 		u32 struct_len;
271 		ceph_decode_8_safe(p, end, struct_v, bad);
272 		ceph_decode_8_safe(p, end, struct_compat, bad);
273 		/* struct_v is expected to be >= 1. we only understand
274 		 * encoding whose struct_compat == 1. */
275 		if (!struct_v || struct_compat != 1)
276 			goto bad;
277 		ceph_decode_32_safe(p, end, struct_len, bad);
278 		ceph_decode_need(p, end, struct_len, bad);
279 		end = *p + struct_len;
280 	}
281 
282 	ceph_decode_need(p, end, sizeof(**lease), bad);
283 	*lease = *p;
284 	*p += sizeof(**lease);
285 	if (features == (u64)-1)
286 		*p = end;
287 	return 0;
288 bad:
289 	return -EIO;
290 }
291 
292 /*
293  * parse a normal reply, which may contain a (dir+)dentry and/or a
294  * target inode.
295  */
296 static int parse_reply_info_trace(void **p, void *end,
297 				  struct ceph_mds_reply_info_parsed *info,
298 				  u64 features)
299 {
300 	int err;
301 
302 	if (info->head->is_dentry) {
303 		err = parse_reply_info_in(p, end, &info->diri, features);
304 		if (err < 0)
305 			goto out_bad;
306 
307 		err = parse_reply_info_dir(p, end, &info->dirfrag, features);
308 		if (err < 0)
309 			goto out_bad;
310 
311 		ceph_decode_32_safe(p, end, info->dname_len, bad);
312 		ceph_decode_need(p, end, info->dname_len, bad);
313 		info->dname = *p;
314 		*p += info->dname_len;
315 
316 		err = parse_reply_info_lease(p, end, &info->dlease, features);
317 		if (err < 0)
318 			goto out_bad;
319 	}
320 
321 	if (info->head->is_target) {
322 		err = parse_reply_info_in(p, end, &info->targeti, features);
323 		if (err < 0)
324 			goto out_bad;
325 	}
326 
327 	if (unlikely(*p != end))
328 		goto bad;
329 	return 0;
330 
331 bad:
332 	err = -EIO;
333 out_bad:
334 	pr_err("problem parsing mds trace %d\n", err);
335 	return err;
336 }
337 
338 /*
339  * parse readdir results
340  */
341 static int parse_reply_info_readdir(void **p, void *end,
342 				struct ceph_mds_reply_info_parsed *info,
343 				u64 features)
344 {
345 	u32 num, i = 0;
346 	int err;
347 
348 	err = parse_reply_info_dir(p, end, &info->dir_dir, features);
349 	if (err < 0)
350 		goto out_bad;
351 
352 	ceph_decode_need(p, end, sizeof(num) + 2, bad);
353 	num = ceph_decode_32(p);
354 	{
355 		u16 flags = ceph_decode_16(p);
356 		info->dir_end = !!(flags & CEPH_READDIR_FRAG_END);
357 		info->dir_complete = !!(flags & CEPH_READDIR_FRAG_COMPLETE);
358 		info->hash_order = !!(flags & CEPH_READDIR_HASH_ORDER);
359 		info->offset_hash = !!(flags & CEPH_READDIR_OFFSET_HASH);
360 	}
361 	if (num == 0)
362 		goto done;
363 
364 	BUG_ON(!info->dir_entries);
365 	if ((unsigned long)(info->dir_entries + num) >
366 	    (unsigned long)info->dir_entries + info->dir_buf_size) {
367 		pr_err("dir contents are larger than expected\n");
368 		WARN_ON(1);
369 		goto bad;
370 	}
371 
372 	info->dir_nr = num;
373 	while (num) {
374 		struct ceph_mds_reply_dir_entry *rde = info->dir_entries + i;
375 		/* dentry */
376 		ceph_decode_32_safe(p, end, rde->name_len, bad);
377 		ceph_decode_need(p, end, rde->name_len, bad);
378 		rde->name = *p;
379 		*p += rde->name_len;
380 		dout("parsed dir dname '%.*s'\n", rde->name_len, rde->name);
381 
382 		/* dentry lease */
383 		err = parse_reply_info_lease(p, end, &rde->lease, features);
384 		if (err)
385 			goto out_bad;
386 		/* inode */
387 		err = parse_reply_info_in(p, end, &rde->inode, features);
388 		if (err < 0)
389 			goto out_bad;
390 		/* ceph_readdir_prepopulate() will update it */
391 		rde->offset = 0;
392 		i++;
393 		num--;
394 	}
395 
396 done:
397 	/* Skip over any unrecognized fields */
398 	*p = end;
399 	return 0;
400 
401 bad:
402 	err = -EIO;
403 out_bad:
404 	pr_err("problem parsing dir contents %d\n", err);
405 	return err;
406 }
407 
408 /*
409  * parse fcntl F_GETLK results
410  */
411 static int parse_reply_info_filelock(void **p, void *end,
412 				     struct ceph_mds_reply_info_parsed *info,
413 				     u64 features)
414 {
415 	if (*p + sizeof(*info->filelock_reply) > end)
416 		goto bad;
417 
418 	info->filelock_reply = *p;
419 
420 	/* Skip over any unrecognized fields */
421 	*p = end;
422 	return 0;
423 bad:
424 	return -EIO;
425 }
426 
427 
428 #if BITS_PER_LONG == 64
429 
430 #define DELEGATED_INO_AVAILABLE		xa_mk_value(1)
431 
432 static int ceph_parse_deleg_inos(void **p, void *end,
433 				 struct ceph_mds_session *s)
434 {
435 	u32 sets;
436 
437 	ceph_decode_32_safe(p, end, sets, bad);
438 	dout("got %u sets of delegated inodes\n", sets);
439 	while (sets--) {
440 		u64 start, len, ino;
441 
442 		ceph_decode_64_safe(p, end, start, bad);
443 		ceph_decode_64_safe(p, end, len, bad);
444 
445 		/* Don't accept a delegation of system inodes */
446 		if (start < CEPH_INO_SYSTEM_BASE) {
447 			pr_warn_ratelimited("ceph: ignoring reserved inode range delegation (start=0x%llx len=0x%llx)\n",
448 					start, len);
449 			continue;
450 		}
451 		while (len--) {
452 			int err = xa_insert(&s->s_delegated_inos, ino = start++,
453 					    DELEGATED_INO_AVAILABLE,
454 					    GFP_KERNEL);
455 			if (!err) {
456 				dout("added delegated inode 0x%llx\n",
457 				     start - 1);
458 			} else if (err == -EBUSY) {
459 				pr_warn("ceph: MDS delegated inode 0x%llx more than once.\n",
460 					start - 1);
461 			} else {
462 				return err;
463 			}
464 		}
465 	}
466 	return 0;
467 bad:
468 	return -EIO;
469 }
470 
471 u64 ceph_get_deleg_ino(struct ceph_mds_session *s)
472 {
473 	unsigned long ino;
474 	void *val;
475 
476 	xa_for_each(&s->s_delegated_inos, ino, val) {
477 		val = xa_erase(&s->s_delegated_inos, ino);
478 		if (val == DELEGATED_INO_AVAILABLE)
479 			return ino;
480 	}
481 	return 0;
482 }
483 
484 int ceph_restore_deleg_ino(struct ceph_mds_session *s, u64 ino)
485 {
486 	return xa_insert(&s->s_delegated_inos, ino, DELEGATED_INO_AVAILABLE,
487 			 GFP_KERNEL);
488 }
489 #else /* BITS_PER_LONG == 64 */
490 /*
491  * FIXME: xarrays can't handle 64-bit indexes on a 32-bit arch. For now, just
492  * ignore delegated_inos on 32 bit arch. Maybe eventually add xarrays for top
493  * and bottom words?
494  */
495 static int ceph_parse_deleg_inos(void **p, void *end,
496 				 struct ceph_mds_session *s)
497 {
498 	u32 sets;
499 
500 	ceph_decode_32_safe(p, end, sets, bad);
501 	if (sets)
502 		ceph_decode_skip_n(p, end, sets * 2 * sizeof(__le64), bad);
503 	return 0;
504 bad:
505 	return -EIO;
506 }
507 
508 u64 ceph_get_deleg_ino(struct ceph_mds_session *s)
509 {
510 	return 0;
511 }
512 
513 int ceph_restore_deleg_ino(struct ceph_mds_session *s, u64 ino)
514 {
515 	return 0;
516 }
517 #endif /* BITS_PER_LONG == 64 */
518 
519 /*
520  * parse create results
521  */
522 static int parse_reply_info_create(void **p, void *end,
523 				  struct ceph_mds_reply_info_parsed *info,
524 				  u64 features, struct ceph_mds_session *s)
525 {
526 	int ret;
527 
528 	if (features == (u64)-1 ||
529 	    (features & CEPH_FEATURE_REPLY_CREATE_INODE)) {
530 		if (*p == end) {
531 			/* Malformed reply? */
532 			info->has_create_ino = false;
533 		} else if (test_bit(CEPHFS_FEATURE_DELEG_INO, &s->s_features)) {
534 			info->has_create_ino = true;
535 			/* struct_v, struct_compat, and len */
536 			ceph_decode_skip_n(p, end, 2 + sizeof(u32), bad);
537 			ceph_decode_64_safe(p, end, info->ino, bad);
538 			ret = ceph_parse_deleg_inos(p, end, s);
539 			if (ret)
540 				return ret;
541 		} else {
542 			/* legacy */
543 			ceph_decode_64_safe(p, end, info->ino, bad);
544 			info->has_create_ino = true;
545 		}
546 	} else {
547 		if (*p != end)
548 			goto bad;
549 	}
550 
551 	/* Skip over any unrecognized fields */
552 	*p = end;
553 	return 0;
554 bad:
555 	return -EIO;
556 }
557 
558 static int parse_reply_info_getvxattr(void **p, void *end,
559 				      struct ceph_mds_reply_info_parsed *info,
560 				      u64 features)
561 {
562 	u32 value_len;
563 
564 	ceph_decode_skip_8(p, end, bad); /* skip current version: 1 */
565 	ceph_decode_skip_8(p, end, bad); /* skip first version: 1 */
566 	ceph_decode_skip_32(p, end, bad); /* skip payload length */
567 
568 	ceph_decode_32_safe(p, end, value_len, bad);
569 
570 	if (value_len == end - *p) {
571 	  info->xattr_info.xattr_value = *p;
572 	  info->xattr_info.xattr_value_len = value_len;
573 	  *p = end;
574 	  return value_len;
575 	}
576 bad:
577 	return -EIO;
578 }
579 
580 /*
581  * parse extra results
582  */
583 static int parse_reply_info_extra(void **p, void *end,
584 				  struct ceph_mds_reply_info_parsed *info,
585 				  u64 features, struct ceph_mds_session *s)
586 {
587 	u32 op = le32_to_cpu(info->head->op);
588 
589 	if (op == CEPH_MDS_OP_GETFILELOCK)
590 		return parse_reply_info_filelock(p, end, info, features);
591 	else if (op == CEPH_MDS_OP_READDIR || op == CEPH_MDS_OP_LSSNAP)
592 		return parse_reply_info_readdir(p, end, info, features);
593 	else if (op == CEPH_MDS_OP_CREATE)
594 		return parse_reply_info_create(p, end, info, features, s);
595 	else if (op == CEPH_MDS_OP_GETVXATTR)
596 		return parse_reply_info_getvxattr(p, end, info, features);
597 	else
598 		return -EIO;
599 }
600 
601 /*
602  * parse entire mds reply
603  */
604 static int parse_reply_info(struct ceph_mds_session *s, struct ceph_msg *msg,
605 			    struct ceph_mds_reply_info_parsed *info,
606 			    u64 features)
607 {
608 	void *p, *end;
609 	u32 len;
610 	int err;
611 
612 	info->head = msg->front.iov_base;
613 	p = msg->front.iov_base + sizeof(struct ceph_mds_reply_head);
614 	end = p + msg->front.iov_len - sizeof(struct ceph_mds_reply_head);
615 
616 	/* trace */
617 	ceph_decode_32_safe(&p, end, len, bad);
618 	if (len > 0) {
619 		ceph_decode_need(&p, end, len, bad);
620 		err = parse_reply_info_trace(&p, p+len, info, features);
621 		if (err < 0)
622 			goto out_bad;
623 	}
624 
625 	/* extra */
626 	ceph_decode_32_safe(&p, end, len, bad);
627 	if (len > 0) {
628 		ceph_decode_need(&p, end, len, bad);
629 		err = parse_reply_info_extra(&p, p+len, info, features, s);
630 		if (err < 0)
631 			goto out_bad;
632 	}
633 
634 	/* snap blob */
635 	ceph_decode_32_safe(&p, end, len, bad);
636 	info->snapblob_len = len;
637 	info->snapblob = p;
638 	p += len;
639 
640 	if (p != end)
641 		goto bad;
642 	return 0;
643 
644 bad:
645 	err = -EIO;
646 out_bad:
647 	pr_err("mds parse_reply err %d\n", err);
648 	return err;
649 }
650 
651 static void destroy_reply_info(struct ceph_mds_reply_info_parsed *info)
652 {
653 	if (!info->dir_entries)
654 		return;
655 	free_pages((unsigned long)info->dir_entries, get_order(info->dir_buf_size));
656 }
657 
658 
659 /*
660  * sessions
661  */
662 const char *ceph_session_state_name(int s)
663 {
664 	switch (s) {
665 	case CEPH_MDS_SESSION_NEW: return "new";
666 	case CEPH_MDS_SESSION_OPENING: return "opening";
667 	case CEPH_MDS_SESSION_OPEN: return "open";
668 	case CEPH_MDS_SESSION_HUNG: return "hung";
669 	case CEPH_MDS_SESSION_CLOSING: return "closing";
670 	case CEPH_MDS_SESSION_CLOSED: return "closed";
671 	case CEPH_MDS_SESSION_RESTARTING: return "restarting";
672 	case CEPH_MDS_SESSION_RECONNECTING: return "reconnecting";
673 	case CEPH_MDS_SESSION_REJECTED: return "rejected";
674 	default: return "???";
675 	}
676 }
677 
678 struct ceph_mds_session *ceph_get_mds_session(struct ceph_mds_session *s)
679 {
680 	if (refcount_inc_not_zero(&s->s_ref))
681 		return s;
682 	return NULL;
683 }
684 
685 void ceph_put_mds_session(struct ceph_mds_session *s)
686 {
687 	if (IS_ERR_OR_NULL(s))
688 		return;
689 
690 	if (refcount_dec_and_test(&s->s_ref)) {
691 		if (s->s_auth.authorizer)
692 			ceph_auth_destroy_authorizer(s->s_auth.authorizer);
693 		WARN_ON(mutex_is_locked(&s->s_mutex));
694 		xa_destroy(&s->s_delegated_inos);
695 		kfree(s);
696 	}
697 }
698 
699 /*
700  * called under mdsc->mutex
701  */
702 struct ceph_mds_session *__ceph_lookup_mds_session(struct ceph_mds_client *mdsc,
703 						   int mds)
704 {
705 	if (mds >= mdsc->max_sessions || !mdsc->sessions[mds])
706 		return NULL;
707 	return ceph_get_mds_session(mdsc->sessions[mds]);
708 }
709 
710 static bool __have_session(struct ceph_mds_client *mdsc, int mds)
711 {
712 	if (mds >= mdsc->max_sessions || !mdsc->sessions[mds])
713 		return false;
714 	else
715 		return true;
716 }
717 
718 static int __verify_registered_session(struct ceph_mds_client *mdsc,
719 				       struct ceph_mds_session *s)
720 {
721 	if (s->s_mds >= mdsc->max_sessions ||
722 	    mdsc->sessions[s->s_mds] != s)
723 		return -ENOENT;
724 	return 0;
725 }
726 
727 /*
728  * create+register a new session for given mds.
729  * called under mdsc->mutex.
730  */
731 static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
732 						 int mds)
733 {
734 	struct ceph_mds_session *s;
735 
736 	if (mds >= mdsc->mdsmap->possible_max_rank)
737 		return ERR_PTR(-EINVAL);
738 
739 	s = kzalloc(sizeof(*s), GFP_NOFS);
740 	if (!s)
741 		return ERR_PTR(-ENOMEM);
742 
743 	if (mds >= mdsc->max_sessions) {
744 		int newmax = 1 << get_count_order(mds + 1);
745 		struct ceph_mds_session **sa;
746 
747 		dout("%s: realloc to %d\n", __func__, newmax);
748 		sa = kcalloc(newmax, sizeof(void *), GFP_NOFS);
749 		if (!sa)
750 			goto fail_realloc;
751 		if (mdsc->sessions) {
752 			memcpy(sa, mdsc->sessions,
753 			       mdsc->max_sessions * sizeof(void *));
754 			kfree(mdsc->sessions);
755 		}
756 		mdsc->sessions = sa;
757 		mdsc->max_sessions = newmax;
758 	}
759 
760 	dout("%s: mds%d\n", __func__, mds);
761 	s->s_mdsc = mdsc;
762 	s->s_mds = mds;
763 	s->s_state = CEPH_MDS_SESSION_NEW;
764 	mutex_init(&s->s_mutex);
765 
766 	ceph_con_init(&s->s_con, s, &mds_con_ops, &mdsc->fsc->client->msgr);
767 
768 	atomic_set(&s->s_cap_gen, 1);
769 	s->s_cap_ttl = jiffies - 1;
770 
771 	spin_lock_init(&s->s_cap_lock);
772 	INIT_LIST_HEAD(&s->s_caps);
773 	refcount_set(&s->s_ref, 1);
774 	INIT_LIST_HEAD(&s->s_waiting);
775 	INIT_LIST_HEAD(&s->s_unsafe);
776 	xa_init(&s->s_delegated_inos);
777 	INIT_LIST_HEAD(&s->s_cap_releases);
778 	INIT_WORK(&s->s_cap_release_work, ceph_cap_release_work);
779 
780 	INIT_LIST_HEAD(&s->s_cap_dirty);
781 	INIT_LIST_HEAD(&s->s_cap_flushing);
782 
783 	mdsc->sessions[mds] = s;
784 	atomic_inc(&mdsc->num_sessions);
785 	refcount_inc(&s->s_ref);  /* one ref to sessions[], one to caller */
786 
787 	ceph_con_open(&s->s_con, CEPH_ENTITY_TYPE_MDS, mds,
788 		      ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
789 
790 	return s;
791 
792 fail_realloc:
793 	kfree(s);
794 	return ERR_PTR(-ENOMEM);
795 }
796 
797 /*
798  * called under mdsc->mutex
799  */
800 static void __unregister_session(struct ceph_mds_client *mdsc,
801 			       struct ceph_mds_session *s)
802 {
803 	dout("__unregister_session mds%d %p\n", s->s_mds, s);
804 	BUG_ON(mdsc->sessions[s->s_mds] != s);
805 	mdsc->sessions[s->s_mds] = NULL;
806 	ceph_con_close(&s->s_con);
807 	ceph_put_mds_session(s);
808 	atomic_dec(&mdsc->num_sessions);
809 }
810 
811 /*
812  * drop session refs in request.
813  *
814  * should be last request ref, or hold mdsc->mutex
815  */
816 static void put_request_session(struct ceph_mds_request *req)
817 {
818 	if (req->r_session) {
819 		ceph_put_mds_session(req->r_session);
820 		req->r_session = NULL;
821 	}
822 }
823 
824 void ceph_mdsc_iterate_sessions(struct ceph_mds_client *mdsc,
825 				void (*cb)(struct ceph_mds_session *),
826 				bool check_state)
827 {
828 	int mds;
829 
830 	mutex_lock(&mdsc->mutex);
831 	for (mds = 0; mds < mdsc->max_sessions; ++mds) {
832 		struct ceph_mds_session *s;
833 
834 		s = __ceph_lookup_mds_session(mdsc, mds);
835 		if (!s)
836 			continue;
837 
838 		if (check_state && !check_session_state(s)) {
839 			ceph_put_mds_session(s);
840 			continue;
841 		}
842 
843 		mutex_unlock(&mdsc->mutex);
844 		cb(s);
845 		ceph_put_mds_session(s);
846 		mutex_lock(&mdsc->mutex);
847 	}
848 	mutex_unlock(&mdsc->mutex);
849 }
850 
851 void ceph_mdsc_release_request(struct kref *kref)
852 {
853 	struct ceph_mds_request *req = container_of(kref,
854 						    struct ceph_mds_request,
855 						    r_kref);
856 	ceph_mdsc_release_dir_caps_no_check(req);
857 	destroy_reply_info(&req->r_reply_info);
858 	if (req->r_request)
859 		ceph_msg_put(req->r_request);
860 	if (req->r_reply)
861 		ceph_msg_put(req->r_reply);
862 	if (req->r_inode) {
863 		ceph_put_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
864 		iput(req->r_inode);
865 	}
866 	if (req->r_parent) {
867 		ceph_put_cap_refs(ceph_inode(req->r_parent), CEPH_CAP_PIN);
868 		iput(req->r_parent);
869 	}
870 	iput(req->r_target_inode);
871 	if (req->r_dentry)
872 		dput(req->r_dentry);
873 	if (req->r_old_dentry)
874 		dput(req->r_old_dentry);
875 	if (req->r_old_dentry_dir) {
876 		/*
877 		 * track (and drop pins for) r_old_dentry_dir
878 		 * separately, since r_old_dentry's d_parent may have
879 		 * changed between the dir mutex being dropped and
880 		 * this request being freed.
881 		 */
882 		ceph_put_cap_refs(ceph_inode(req->r_old_dentry_dir),
883 				  CEPH_CAP_PIN);
884 		iput(req->r_old_dentry_dir);
885 	}
886 	kfree(req->r_path1);
887 	kfree(req->r_path2);
888 	put_cred(req->r_cred);
889 	if (req->r_pagelist)
890 		ceph_pagelist_release(req->r_pagelist);
891 	put_request_session(req);
892 	ceph_unreserve_caps(req->r_mdsc, &req->r_caps_reservation);
893 	WARN_ON_ONCE(!list_empty(&req->r_wait));
894 	kmem_cache_free(ceph_mds_request_cachep, req);
895 }
896 
897 DEFINE_RB_FUNCS(request, struct ceph_mds_request, r_tid, r_node)
898 
899 /*
900  * lookup session, bump ref if found.
901  *
902  * called under mdsc->mutex.
903  */
904 static struct ceph_mds_request *
905 lookup_get_request(struct ceph_mds_client *mdsc, u64 tid)
906 {
907 	struct ceph_mds_request *req;
908 
909 	req = lookup_request(&mdsc->request_tree, tid);
910 	if (req)
911 		ceph_mdsc_get_request(req);
912 
913 	return req;
914 }
915 
916 /*
917  * Register an in-flight request, and assign a tid.  Link to directory
918  * are modifying (if any).
919  *
920  * Called under mdsc->mutex.
921  */
922 static void __register_request(struct ceph_mds_client *mdsc,
923 			       struct ceph_mds_request *req,
924 			       struct inode *dir)
925 {
926 	int ret = 0;
927 
928 	req->r_tid = ++mdsc->last_tid;
929 	if (req->r_num_caps) {
930 		ret = ceph_reserve_caps(mdsc, &req->r_caps_reservation,
931 					req->r_num_caps);
932 		if (ret < 0) {
933 			pr_err("__register_request %p "
934 			       "failed to reserve caps: %d\n", req, ret);
935 			/* set req->r_err to fail early from __do_request */
936 			req->r_err = ret;
937 			return;
938 		}
939 	}
940 	dout("__register_request %p tid %lld\n", req, req->r_tid);
941 	ceph_mdsc_get_request(req);
942 	insert_request(&mdsc->request_tree, req);
943 
944 	req->r_cred = get_current_cred();
945 
946 	if (mdsc->oldest_tid == 0 && req->r_op != CEPH_MDS_OP_SETFILELOCK)
947 		mdsc->oldest_tid = req->r_tid;
948 
949 	if (dir) {
950 		struct ceph_inode_info *ci = ceph_inode(dir);
951 
952 		ihold(dir);
953 		req->r_unsafe_dir = dir;
954 		spin_lock(&ci->i_unsafe_lock);
955 		list_add_tail(&req->r_unsafe_dir_item, &ci->i_unsafe_dirops);
956 		spin_unlock(&ci->i_unsafe_lock);
957 	}
958 }
959 
960 static void __unregister_request(struct ceph_mds_client *mdsc,
961 				 struct ceph_mds_request *req)
962 {
963 	dout("__unregister_request %p tid %lld\n", req, req->r_tid);
964 
965 	/* Never leave an unregistered request on an unsafe list! */
966 	list_del_init(&req->r_unsafe_item);
967 
968 	if (req->r_tid == mdsc->oldest_tid) {
969 		struct rb_node *p = rb_next(&req->r_node);
970 		mdsc->oldest_tid = 0;
971 		while (p) {
972 			struct ceph_mds_request *next_req =
973 				rb_entry(p, struct ceph_mds_request, r_node);
974 			if (next_req->r_op != CEPH_MDS_OP_SETFILELOCK) {
975 				mdsc->oldest_tid = next_req->r_tid;
976 				break;
977 			}
978 			p = rb_next(p);
979 		}
980 	}
981 
982 	erase_request(&mdsc->request_tree, req);
983 
984 	if (req->r_unsafe_dir) {
985 		struct ceph_inode_info *ci = ceph_inode(req->r_unsafe_dir);
986 		spin_lock(&ci->i_unsafe_lock);
987 		list_del_init(&req->r_unsafe_dir_item);
988 		spin_unlock(&ci->i_unsafe_lock);
989 	}
990 	if (req->r_target_inode &&
991 	    test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
992 		struct ceph_inode_info *ci = ceph_inode(req->r_target_inode);
993 		spin_lock(&ci->i_unsafe_lock);
994 		list_del_init(&req->r_unsafe_target_item);
995 		spin_unlock(&ci->i_unsafe_lock);
996 	}
997 
998 	if (req->r_unsafe_dir) {
999 		iput(req->r_unsafe_dir);
1000 		req->r_unsafe_dir = NULL;
1001 	}
1002 
1003 	complete_all(&req->r_safe_completion);
1004 
1005 	ceph_mdsc_put_request(req);
1006 }
1007 
1008 /*
1009  * Walk back up the dentry tree until we hit a dentry representing a
1010  * non-snapshot inode. We do this using the rcu_read_lock (which must be held
1011  * when calling this) to ensure that the objects won't disappear while we're
1012  * working with them. Once we hit a candidate dentry, we attempt to take a
1013  * reference to it, and return that as the result.
1014  */
1015 static struct inode *get_nonsnap_parent(struct dentry *dentry)
1016 {
1017 	struct inode *inode = NULL;
1018 
1019 	while (dentry && !IS_ROOT(dentry)) {
1020 		inode = d_inode_rcu(dentry);
1021 		if (!inode || ceph_snap(inode) == CEPH_NOSNAP)
1022 			break;
1023 		dentry = dentry->d_parent;
1024 	}
1025 	if (inode)
1026 		inode = igrab(inode);
1027 	return inode;
1028 }
1029 
1030 /*
1031  * Choose mds to send request to next.  If there is a hint set in the
1032  * request (e.g., due to a prior forward hint from the mds), use that.
1033  * Otherwise, consult frag tree and/or caps to identify the
1034  * appropriate mds.  If all else fails, choose randomly.
1035  *
1036  * Called under mdsc->mutex.
1037  */
1038 static int __choose_mds(struct ceph_mds_client *mdsc,
1039 			struct ceph_mds_request *req,
1040 			bool *random)
1041 {
1042 	struct inode *inode;
1043 	struct ceph_inode_info *ci;
1044 	struct ceph_cap *cap;
1045 	int mode = req->r_direct_mode;
1046 	int mds = -1;
1047 	u32 hash = req->r_direct_hash;
1048 	bool is_hash = test_bit(CEPH_MDS_R_DIRECT_IS_HASH, &req->r_req_flags);
1049 
1050 	if (random)
1051 		*random = false;
1052 
1053 	/*
1054 	 * is there a specific mds we should try?  ignore hint if we have
1055 	 * no session and the mds is not up (active or recovering).
1056 	 */
1057 	if (req->r_resend_mds >= 0 &&
1058 	    (__have_session(mdsc, req->r_resend_mds) ||
1059 	     ceph_mdsmap_get_state(mdsc->mdsmap, req->r_resend_mds) > 0)) {
1060 		dout("%s using resend_mds mds%d\n", __func__,
1061 		     req->r_resend_mds);
1062 		return req->r_resend_mds;
1063 	}
1064 
1065 	if (mode == USE_RANDOM_MDS)
1066 		goto random;
1067 
1068 	inode = NULL;
1069 	if (req->r_inode) {
1070 		if (ceph_snap(req->r_inode) != CEPH_SNAPDIR) {
1071 			inode = req->r_inode;
1072 			ihold(inode);
1073 		} else {
1074 			/* req->r_dentry is non-null for LSSNAP request */
1075 			rcu_read_lock();
1076 			inode = get_nonsnap_parent(req->r_dentry);
1077 			rcu_read_unlock();
1078 			dout("%s using snapdir's parent %p\n", __func__, inode);
1079 		}
1080 	} else if (req->r_dentry) {
1081 		/* ignore race with rename; old or new d_parent is okay */
1082 		struct dentry *parent;
1083 		struct inode *dir;
1084 
1085 		rcu_read_lock();
1086 		parent = READ_ONCE(req->r_dentry->d_parent);
1087 		dir = req->r_parent ? : d_inode_rcu(parent);
1088 
1089 		if (!dir || dir->i_sb != mdsc->fsc->sb) {
1090 			/*  not this fs or parent went negative */
1091 			inode = d_inode(req->r_dentry);
1092 			if (inode)
1093 				ihold(inode);
1094 		} else if (ceph_snap(dir) != CEPH_NOSNAP) {
1095 			/* direct snapped/virtual snapdir requests
1096 			 * based on parent dir inode */
1097 			inode = get_nonsnap_parent(parent);
1098 			dout("%s using nonsnap parent %p\n", __func__, inode);
1099 		} else {
1100 			/* dentry target */
1101 			inode = d_inode(req->r_dentry);
1102 			if (!inode || mode == USE_AUTH_MDS) {
1103 				/* dir + name */
1104 				inode = igrab(dir);
1105 				hash = ceph_dentry_hash(dir, req->r_dentry);
1106 				is_hash = true;
1107 			} else {
1108 				ihold(inode);
1109 			}
1110 		}
1111 		rcu_read_unlock();
1112 	}
1113 
1114 	dout("%s %p is_hash=%d (0x%x) mode %d\n", __func__, inode, (int)is_hash,
1115 	     hash, mode);
1116 	if (!inode)
1117 		goto random;
1118 	ci = ceph_inode(inode);
1119 
1120 	if (is_hash && S_ISDIR(inode->i_mode)) {
1121 		struct ceph_inode_frag frag;
1122 		int found;
1123 
1124 		ceph_choose_frag(ci, hash, &frag, &found);
1125 		if (found) {
1126 			if (mode == USE_ANY_MDS && frag.ndist > 0) {
1127 				u8 r;
1128 
1129 				/* choose a random replica */
1130 				get_random_bytes(&r, 1);
1131 				r %= frag.ndist;
1132 				mds = frag.dist[r];
1133 				dout("%s %p %llx.%llx frag %u mds%d (%d/%d)\n",
1134 				     __func__, inode, ceph_vinop(inode),
1135 				     frag.frag, mds, (int)r, frag.ndist);
1136 				if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
1137 				    CEPH_MDS_STATE_ACTIVE &&
1138 				    !ceph_mdsmap_is_laggy(mdsc->mdsmap, mds))
1139 					goto out;
1140 			}
1141 
1142 			/* since this file/dir wasn't known to be
1143 			 * replicated, then we want to look for the
1144 			 * authoritative mds. */
1145 			if (frag.mds >= 0) {
1146 				/* choose auth mds */
1147 				mds = frag.mds;
1148 				dout("%s %p %llx.%llx frag %u mds%d (auth)\n",
1149 				     __func__, inode, ceph_vinop(inode),
1150 				     frag.frag, mds);
1151 				if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
1152 				    CEPH_MDS_STATE_ACTIVE) {
1153 					if (!ceph_mdsmap_is_laggy(mdsc->mdsmap,
1154 								  mds))
1155 						goto out;
1156 				}
1157 			}
1158 			mode = USE_AUTH_MDS;
1159 		}
1160 	}
1161 
1162 	spin_lock(&ci->i_ceph_lock);
1163 	cap = NULL;
1164 	if (mode == USE_AUTH_MDS)
1165 		cap = ci->i_auth_cap;
1166 	if (!cap && !RB_EMPTY_ROOT(&ci->i_caps))
1167 		cap = rb_entry(rb_first(&ci->i_caps), struct ceph_cap, ci_node);
1168 	if (!cap) {
1169 		spin_unlock(&ci->i_ceph_lock);
1170 		iput(inode);
1171 		goto random;
1172 	}
1173 	mds = cap->session->s_mds;
1174 	dout("%s %p %llx.%llx mds%d (%scap %p)\n", __func__,
1175 	     inode, ceph_vinop(inode), mds,
1176 	     cap == ci->i_auth_cap ? "auth " : "", cap);
1177 	spin_unlock(&ci->i_ceph_lock);
1178 out:
1179 	iput(inode);
1180 	return mds;
1181 
1182 random:
1183 	if (random)
1184 		*random = true;
1185 
1186 	mds = ceph_mdsmap_get_random_mds(mdsc->mdsmap);
1187 	dout("%s chose random mds%d\n", __func__, mds);
1188 	return mds;
1189 }
1190 
1191 
1192 /*
1193  * session messages
1194  */
1195 struct ceph_msg *ceph_create_session_msg(u32 op, u64 seq)
1196 {
1197 	struct ceph_msg *msg;
1198 	struct ceph_mds_session_head *h;
1199 
1200 	msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h), GFP_NOFS,
1201 			   false);
1202 	if (!msg) {
1203 		pr_err("ENOMEM creating session %s msg\n",
1204 		       ceph_session_op_name(op));
1205 		return NULL;
1206 	}
1207 	h = msg->front.iov_base;
1208 	h->op = cpu_to_le32(op);
1209 	h->seq = cpu_to_le64(seq);
1210 
1211 	return msg;
1212 }
1213 
1214 static const unsigned char feature_bits[] = CEPHFS_FEATURES_CLIENT_SUPPORTED;
1215 #define FEATURE_BYTES(c) (DIV_ROUND_UP((size_t)feature_bits[c - 1] + 1, 64) * 8)
1216 static int encode_supported_features(void **p, void *end)
1217 {
1218 	static const size_t count = ARRAY_SIZE(feature_bits);
1219 
1220 	if (count > 0) {
1221 		size_t i;
1222 		size_t size = FEATURE_BYTES(count);
1223 
1224 		if (WARN_ON_ONCE(*p + 4 + size > end))
1225 			return -ERANGE;
1226 
1227 		ceph_encode_32(p, size);
1228 		memset(*p, 0, size);
1229 		for (i = 0; i < count; i++)
1230 			((unsigned char*)(*p))[i / 8] |= BIT(feature_bits[i] % 8);
1231 		*p += size;
1232 	} else {
1233 		if (WARN_ON_ONCE(*p + 4 > end))
1234 			return -ERANGE;
1235 
1236 		ceph_encode_32(p, 0);
1237 	}
1238 
1239 	return 0;
1240 }
1241 
1242 static const unsigned char metric_bits[] = CEPHFS_METRIC_SPEC_CLIENT_SUPPORTED;
1243 #define METRIC_BYTES(cnt) (DIV_ROUND_UP((size_t)metric_bits[cnt - 1] + 1, 64) * 8)
1244 static int encode_metric_spec(void **p, void *end)
1245 {
1246 	static const size_t count = ARRAY_SIZE(metric_bits);
1247 
1248 	/* header */
1249 	if (WARN_ON_ONCE(*p + 2 > end))
1250 		return -ERANGE;
1251 
1252 	ceph_encode_8(p, 1); /* version */
1253 	ceph_encode_8(p, 1); /* compat */
1254 
1255 	if (count > 0) {
1256 		size_t i;
1257 		size_t size = METRIC_BYTES(count);
1258 
1259 		if (WARN_ON_ONCE(*p + 4 + 4 + size > end))
1260 			return -ERANGE;
1261 
1262 		/* metric spec info length */
1263 		ceph_encode_32(p, 4 + size);
1264 
1265 		/* metric spec */
1266 		ceph_encode_32(p, size);
1267 		memset(*p, 0, size);
1268 		for (i = 0; i < count; i++)
1269 			((unsigned char *)(*p))[i / 8] |= BIT(metric_bits[i] % 8);
1270 		*p += size;
1271 	} else {
1272 		if (WARN_ON_ONCE(*p + 4 + 4 > end))
1273 			return -ERANGE;
1274 
1275 		/* metric spec info length */
1276 		ceph_encode_32(p, 4);
1277 		/* metric spec */
1278 		ceph_encode_32(p, 0);
1279 	}
1280 
1281 	return 0;
1282 }
1283 
1284 /*
1285  * session message, specialization for CEPH_SESSION_REQUEST_OPEN
1286  * to include additional client metadata fields.
1287  */
1288 static struct ceph_msg *create_session_open_msg(struct ceph_mds_client *mdsc, u64 seq)
1289 {
1290 	struct ceph_msg *msg;
1291 	struct ceph_mds_session_head *h;
1292 	int i;
1293 	int extra_bytes = 0;
1294 	int metadata_key_count = 0;
1295 	struct ceph_options *opt = mdsc->fsc->client->options;
1296 	struct ceph_mount_options *fsopt = mdsc->fsc->mount_options;
1297 	size_t size, count;
1298 	void *p, *end;
1299 	int ret;
1300 
1301 	const char* metadata[][2] = {
1302 		{"hostname", mdsc->nodename},
1303 		{"kernel_version", init_utsname()->release},
1304 		{"entity_id", opt->name ? : ""},
1305 		{"root", fsopt->server_path ? : "/"},
1306 		{NULL, NULL}
1307 	};
1308 
1309 	/* Calculate serialized length of metadata */
1310 	extra_bytes = 4;  /* map length */
1311 	for (i = 0; metadata[i][0]; ++i) {
1312 		extra_bytes += 8 + strlen(metadata[i][0]) +
1313 			strlen(metadata[i][1]);
1314 		metadata_key_count++;
1315 	}
1316 
1317 	/* supported feature */
1318 	size = 0;
1319 	count = ARRAY_SIZE(feature_bits);
1320 	if (count > 0)
1321 		size = FEATURE_BYTES(count);
1322 	extra_bytes += 4 + size;
1323 
1324 	/* metric spec */
1325 	size = 0;
1326 	count = ARRAY_SIZE(metric_bits);
1327 	if (count > 0)
1328 		size = METRIC_BYTES(count);
1329 	extra_bytes += 2 + 4 + 4 + size;
1330 
1331 	/* Allocate the message */
1332 	msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h) + extra_bytes,
1333 			   GFP_NOFS, false);
1334 	if (!msg) {
1335 		pr_err("ENOMEM creating session open msg\n");
1336 		return ERR_PTR(-ENOMEM);
1337 	}
1338 	p = msg->front.iov_base;
1339 	end = p + msg->front.iov_len;
1340 
1341 	h = p;
1342 	h->op = cpu_to_le32(CEPH_SESSION_REQUEST_OPEN);
1343 	h->seq = cpu_to_le64(seq);
1344 
1345 	/*
1346 	 * Serialize client metadata into waiting buffer space, using
1347 	 * the format that userspace expects for map<string, string>
1348 	 *
1349 	 * ClientSession messages with metadata are v4
1350 	 */
1351 	msg->hdr.version = cpu_to_le16(4);
1352 	msg->hdr.compat_version = cpu_to_le16(1);
1353 
1354 	/* The write pointer, following the session_head structure */
1355 	p += sizeof(*h);
1356 
1357 	/* Number of entries in the map */
1358 	ceph_encode_32(&p, metadata_key_count);
1359 
1360 	/* Two length-prefixed strings for each entry in the map */
1361 	for (i = 0; metadata[i][0]; ++i) {
1362 		size_t const key_len = strlen(metadata[i][0]);
1363 		size_t const val_len = strlen(metadata[i][1]);
1364 
1365 		ceph_encode_32(&p, key_len);
1366 		memcpy(p, metadata[i][0], key_len);
1367 		p += key_len;
1368 		ceph_encode_32(&p, val_len);
1369 		memcpy(p, metadata[i][1], val_len);
1370 		p += val_len;
1371 	}
1372 
1373 	ret = encode_supported_features(&p, end);
1374 	if (ret) {
1375 		pr_err("encode_supported_features failed!\n");
1376 		ceph_msg_put(msg);
1377 		return ERR_PTR(ret);
1378 	}
1379 
1380 	ret = encode_metric_spec(&p, end);
1381 	if (ret) {
1382 		pr_err("encode_metric_spec failed!\n");
1383 		ceph_msg_put(msg);
1384 		return ERR_PTR(ret);
1385 	}
1386 
1387 	msg->front.iov_len = p - msg->front.iov_base;
1388 	msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
1389 
1390 	return msg;
1391 }
1392 
1393 /*
1394  * send session open request.
1395  *
1396  * called under mdsc->mutex
1397  */
1398 static int __open_session(struct ceph_mds_client *mdsc,
1399 			  struct ceph_mds_session *session)
1400 {
1401 	struct ceph_msg *msg;
1402 	int mstate;
1403 	int mds = session->s_mds;
1404 
1405 	/* wait for mds to go active? */
1406 	mstate = ceph_mdsmap_get_state(mdsc->mdsmap, mds);
1407 	dout("open_session to mds%d (%s)\n", mds,
1408 	     ceph_mds_state_name(mstate));
1409 	session->s_state = CEPH_MDS_SESSION_OPENING;
1410 	session->s_renew_requested = jiffies;
1411 
1412 	/* send connect message */
1413 	msg = create_session_open_msg(mdsc, session->s_seq);
1414 	if (IS_ERR(msg))
1415 		return PTR_ERR(msg);
1416 	ceph_con_send(&session->s_con, msg);
1417 	return 0;
1418 }
1419 
1420 /*
1421  * open sessions for any export targets for the given mds
1422  *
1423  * called under mdsc->mutex
1424  */
1425 static struct ceph_mds_session *
1426 __open_export_target_session(struct ceph_mds_client *mdsc, int target)
1427 {
1428 	struct ceph_mds_session *session;
1429 	int ret;
1430 
1431 	session = __ceph_lookup_mds_session(mdsc, target);
1432 	if (!session) {
1433 		session = register_session(mdsc, target);
1434 		if (IS_ERR(session))
1435 			return session;
1436 	}
1437 	if (session->s_state == CEPH_MDS_SESSION_NEW ||
1438 	    session->s_state == CEPH_MDS_SESSION_CLOSING) {
1439 		ret = __open_session(mdsc, session);
1440 		if (ret)
1441 			return ERR_PTR(ret);
1442 	}
1443 
1444 	return session;
1445 }
1446 
1447 struct ceph_mds_session *
1448 ceph_mdsc_open_export_target_session(struct ceph_mds_client *mdsc, int target)
1449 {
1450 	struct ceph_mds_session *session;
1451 
1452 	dout("open_export_target_session to mds%d\n", target);
1453 
1454 	mutex_lock(&mdsc->mutex);
1455 	session = __open_export_target_session(mdsc, target);
1456 	mutex_unlock(&mdsc->mutex);
1457 
1458 	return session;
1459 }
1460 
1461 static void __open_export_target_sessions(struct ceph_mds_client *mdsc,
1462 					  struct ceph_mds_session *session)
1463 {
1464 	struct ceph_mds_info *mi;
1465 	struct ceph_mds_session *ts;
1466 	int i, mds = session->s_mds;
1467 
1468 	if (mds >= mdsc->mdsmap->possible_max_rank)
1469 		return;
1470 
1471 	mi = &mdsc->mdsmap->m_info[mds];
1472 	dout("open_export_target_sessions for mds%d (%d targets)\n",
1473 	     session->s_mds, mi->num_export_targets);
1474 
1475 	for (i = 0; i < mi->num_export_targets; i++) {
1476 		ts = __open_export_target_session(mdsc, mi->export_targets[i]);
1477 		ceph_put_mds_session(ts);
1478 	}
1479 }
1480 
1481 void ceph_mdsc_open_export_target_sessions(struct ceph_mds_client *mdsc,
1482 					   struct ceph_mds_session *session)
1483 {
1484 	mutex_lock(&mdsc->mutex);
1485 	__open_export_target_sessions(mdsc, session);
1486 	mutex_unlock(&mdsc->mutex);
1487 }
1488 
1489 /*
1490  * session caps
1491  */
1492 
1493 static void detach_cap_releases(struct ceph_mds_session *session,
1494 				struct list_head *target)
1495 {
1496 	lockdep_assert_held(&session->s_cap_lock);
1497 
1498 	list_splice_init(&session->s_cap_releases, target);
1499 	session->s_num_cap_releases = 0;
1500 	dout("dispose_cap_releases mds%d\n", session->s_mds);
1501 }
1502 
1503 static void dispose_cap_releases(struct ceph_mds_client *mdsc,
1504 				 struct list_head *dispose)
1505 {
1506 	while (!list_empty(dispose)) {
1507 		struct ceph_cap *cap;
1508 		/* zero out the in-progress message */
1509 		cap = list_first_entry(dispose, struct ceph_cap, session_caps);
1510 		list_del(&cap->session_caps);
1511 		ceph_put_cap(mdsc, cap);
1512 	}
1513 }
1514 
1515 static void cleanup_session_requests(struct ceph_mds_client *mdsc,
1516 				     struct ceph_mds_session *session)
1517 {
1518 	struct ceph_mds_request *req;
1519 	struct rb_node *p;
1520 
1521 	dout("cleanup_session_requests mds%d\n", session->s_mds);
1522 	mutex_lock(&mdsc->mutex);
1523 	while (!list_empty(&session->s_unsafe)) {
1524 		req = list_first_entry(&session->s_unsafe,
1525 				       struct ceph_mds_request, r_unsafe_item);
1526 		pr_warn_ratelimited(" dropping unsafe request %llu\n",
1527 				    req->r_tid);
1528 		if (req->r_target_inode)
1529 			mapping_set_error(req->r_target_inode->i_mapping, -EIO);
1530 		if (req->r_unsafe_dir)
1531 			mapping_set_error(req->r_unsafe_dir->i_mapping, -EIO);
1532 		__unregister_request(mdsc, req);
1533 	}
1534 	/* zero r_attempts, so kick_requests() will re-send requests */
1535 	p = rb_first(&mdsc->request_tree);
1536 	while (p) {
1537 		req = rb_entry(p, struct ceph_mds_request, r_node);
1538 		p = rb_next(p);
1539 		if (req->r_session &&
1540 		    req->r_session->s_mds == session->s_mds)
1541 			req->r_attempts = 0;
1542 	}
1543 	mutex_unlock(&mdsc->mutex);
1544 }
1545 
1546 /*
1547  * Helper to safely iterate over all caps associated with a session, with
1548  * special care taken to handle a racing __ceph_remove_cap().
1549  *
1550  * Caller must hold session s_mutex.
1551  */
1552 int ceph_iterate_session_caps(struct ceph_mds_session *session,
1553 			      int (*cb)(struct inode *, struct ceph_cap *,
1554 					void *), void *arg)
1555 {
1556 	struct list_head *p;
1557 	struct ceph_cap *cap;
1558 	struct inode *inode, *last_inode = NULL;
1559 	struct ceph_cap *old_cap = NULL;
1560 	int ret;
1561 
1562 	dout("iterate_session_caps %p mds%d\n", session, session->s_mds);
1563 	spin_lock(&session->s_cap_lock);
1564 	p = session->s_caps.next;
1565 	while (p != &session->s_caps) {
1566 		cap = list_entry(p, struct ceph_cap, session_caps);
1567 		inode = igrab(&cap->ci->vfs_inode);
1568 		if (!inode) {
1569 			p = p->next;
1570 			continue;
1571 		}
1572 		session->s_cap_iterator = cap;
1573 		spin_unlock(&session->s_cap_lock);
1574 
1575 		if (last_inode) {
1576 			iput(last_inode);
1577 			last_inode = NULL;
1578 		}
1579 		if (old_cap) {
1580 			ceph_put_cap(session->s_mdsc, old_cap);
1581 			old_cap = NULL;
1582 		}
1583 
1584 		ret = cb(inode, cap, arg);
1585 		last_inode = inode;
1586 
1587 		spin_lock(&session->s_cap_lock);
1588 		p = p->next;
1589 		if (!cap->ci) {
1590 			dout("iterate_session_caps  finishing cap %p removal\n",
1591 			     cap);
1592 			BUG_ON(cap->session != session);
1593 			cap->session = NULL;
1594 			list_del_init(&cap->session_caps);
1595 			session->s_nr_caps--;
1596 			atomic64_dec(&session->s_mdsc->metric.total_caps);
1597 			if (cap->queue_release)
1598 				__ceph_queue_cap_release(session, cap);
1599 			else
1600 				old_cap = cap;  /* put_cap it w/o locks held */
1601 		}
1602 		if (ret < 0)
1603 			goto out;
1604 	}
1605 	ret = 0;
1606 out:
1607 	session->s_cap_iterator = NULL;
1608 	spin_unlock(&session->s_cap_lock);
1609 
1610 	iput(last_inode);
1611 	if (old_cap)
1612 		ceph_put_cap(session->s_mdsc, old_cap);
1613 
1614 	return ret;
1615 }
1616 
1617 static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
1618 				  void *arg)
1619 {
1620 	struct ceph_inode_info *ci = ceph_inode(inode);
1621 	bool invalidate = false;
1622 	int iputs;
1623 
1624 	dout("removing cap %p, ci is %p, inode is %p\n",
1625 	     cap, ci, &ci->vfs_inode);
1626 	spin_lock(&ci->i_ceph_lock);
1627 	iputs = ceph_purge_inode_cap(inode, cap, &invalidate);
1628 	spin_unlock(&ci->i_ceph_lock);
1629 
1630 	wake_up_all(&ci->i_cap_wq);
1631 	if (invalidate)
1632 		ceph_queue_invalidate(inode);
1633 	while (iputs--)
1634 		iput(inode);
1635 	return 0;
1636 }
1637 
1638 /*
1639  * caller must hold session s_mutex
1640  */
1641 static void remove_session_caps(struct ceph_mds_session *session)
1642 {
1643 	struct ceph_fs_client *fsc = session->s_mdsc->fsc;
1644 	struct super_block *sb = fsc->sb;
1645 	LIST_HEAD(dispose);
1646 
1647 	dout("remove_session_caps on %p\n", session);
1648 	ceph_iterate_session_caps(session, remove_session_caps_cb, fsc);
1649 
1650 	wake_up_all(&fsc->mdsc->cap_flushing_wq);
1651 
1652 	spin_lock(&session->s_cap_lock);
1653 	if (session->s_nr_caps > 0) {
1654 		struct inode *inode;
1655 		struct ceph_cap *cap, *prev = NULL;
1656 		struct ceph_vino vino;
1657 		/*
1658 		 * iterate_session_caps() skips inodes that are being
1659 		 * deleted, we need to wait until deletions are complete.
1660 		 * __wait_on_freeing_inode() is designed for the job,
1661 		 * but it is not exported, so use lookup inode function
1662 		 * to access it.
1663 		 */
1664 		while (!list_empty(&session->s_caps)) {
1665 			cap = list_entry(session->s_caps.next,
1666 					 struct ceph_cap, session_caps);
1667 			if (cap == prev)
1668 				break;
1669 			prev = cap;
1670 			vino = cap->ci->i_vino;
1671 			spin_unlock(&session->s_cap_lock);
1672 
1673 			inode = ceph_find_inode(sb, vino);
1674 			iput(inode);
1675 
1676 			spin_lock(&session->s_cap_lock);
1677 		}
1678 	}
1679 
1680 	// drop cap expires and unlock s_cap_lock
1681 	detach_cap_releases(session, &dispose);
1682 
1683 	BUG_ON(session->s_nr_caps > 0);
1684 	BUG_ON(!list_empty(&session->s_cap_flushing));
1685 	spin_unlock(&session->s_cap_lock);
1686 	dispose_cap_releases(session->s_mdsc, &dispose);
1687 }
1688 
1689 enum {
1690 	RECONNECT,
1691 	RENEWCAPS,
1692 	FORCE_RO,
1693 };
1694 
1695 /*
1696  * wake up any threads waiting on this session's caps.  if the cap is
1697  * old (didn't get renewed on the client reconnect), remove it now.
1698  *
1699  * caller must hold s_mutex.
1700  */
1701 static int wake_up_session_cb(struct inode *inode, struct ceph_cap *cap,
1702 			      void *arg)
1703 {
1704 	struct ceph_inode_info *ci = ceph_inode(inode);
1705 	unsigned long ev = (unsigned long)arg;
1706 
1707 	if (ev == RECONNECT) {
1708 		spin_lock(&ci->i_ceph_lock);
1709 		ci->i_wanted_max_size = 0;
1710 		ci->i_requested_max_size = 0;
1711 		spin_unlock(&ci->i_ceph_lock);
1712 	} else if (ev == RENEWCAPS) {
1713 		if (cap->cap_gen < atomic_read(&cap->session->s_cap_gen)) {
1714 			/* mds did not re-issue stale cap */
1715 			spin_lock(&ci->i_ceph_lock);
1716 			cap->issued = cap->implemented = CEPH_CAP_PIN;
1717 			spin_unlock(&ci->i_ceph_lock);
1718 		}
1719 	} else if (ev == FORCE_RO) {
1720 	}
1721 	wake_up_all(&ci->i_cap_wq);
1722 	return 0;
1723 }
1724 
1725 static void wake_up_session_caps(struct ceph_mds_session *session, int ev)
1726 {
1727 	dout("wake_up_session_caps %p mds%d\n", session, session->s_mds);
1728 	ceph_iterate_session_caps(session, wake_up_session_cb,
1729 				  (void *)(unsigned long)ev);
1730 }
1731 
1732 /*
1733  * Send periodic message to MDS renewing all currently held caps.  The
1734  * ack will reset the expiration for all caps from this session.
1735  *
1736  * caller holds s_mutex
1737  */
1738 static int send_renew_caps(struct ceph_mds_client *mdsc,
1739 			   struct ceph_mds_session *session)
1740 {
1741 	struct ceph_msg *msg;
1742 	int state;
1743 
1744 	if (time_after_eq(jiffies, session->s_cap_ttl) &&
1745 	    time_after_eq(session->s_cap_ttl, session->s_renew_requested))
1746 		pr_info("mds%d caps stale\n", session->s_mds);
1747 	session->s_renew_requested = jiffies;
1748 
1749 	/* do not try to renew caps until a recovering mds has reconnected
1750 	 * with its clients. */
1751 	state = ceph_mdsmap_get_state(mdsc->mdsmap, session->s_mds);
1752 	if (state < CEPH_MDS_STATE_RECONNECT) {
1753 		dout("send_renew_caps ignoring mds%d (%s)\n",
1754 		     session->s_mds, ceph_mds_state_name(state));
1755 		return 0;
1756 	}
1757 
1758 	dout("send_renew_caps to mds%d (%s)\n", session->s_mds,
1759 		ceph_mds_state_name(state));
1760 	msg = ceph_create_session_msg(CEPH_SESSION_REQUEST_RENEWCAPS,
1761 				      ++session->s_renew_seq);
1762 	if (!msg)
1763 		return -ENOMEM;
1764 	ceph_con_send(&session->s_con, msg);
1765 	return 0;
1766 }
1767 
1768 static int send_flushmsg_ack(struct ceph_mds_client *mdsc,
1769 			     struct ceph_mds_session *session, u64 seq)
1770 {
1771 	struct ceph_msg *msg;
1772 
1773 	dout("send_flushmsg_ack to mds%d (%s)s seq %lld\n",
1774 	     session->s_mds, ceph_session_state_name(session->s_state), seq);
1775 	msg = ceph_create_session_msg(CEPH_SESSION_FLUSHMSG_ACK, seq);
1776 	if (!msg)
1777 		return -ENOMEM;
1778 	ceph_con_send(&session->s_con, msg);
1779 	return 0;
1780 }
1781 
1782 
1783 /*
1784  * Note new cap ttl, and any transition from stale -> not stale (fresh?).
1785  *
1786  * Called under session->s_mutex
1787  */
1788 static void renewed_caps(struct ceph_mds_client *mdsc,
1789 			 struct ceph_mds_session *session, int is_renew)
1790 {
1791 	int was_stale;
1792 	int wake = 0;
1793 
1794 	spin_lock(&session->s_cap_lock);
1795 	was_stale = is_renew && time_after_eq(jiffies, session->s_cap_ttl);
1796 
1797 	session->s_cap_ttl = session->s_renew_requested +
1798 		mdsc->mdsmap->m_session_timeout*HZ;
1799 
1800 	if (was_stale) {
1801 		if (time_before(jiffies, session->s_cap_ttl)) {
1802 			pr_info("mds%d caps renewed\n", session->s_mds);
1803 			wake = 1;
1804 		} else {
1805 			pr_info("mds%d caps still stale\n", session->s_mds);
1806 		}
1807 	}
1808 	dout("renewed_caps mds%d ttl now %lu, was %s, now %s\n",
1809 	     session->s_mds, session->s_cap_ttl, was_stale ? "stale" : "fresh",
1810 	     time_before(jiffies, session->s_cap_ttl) ? "stale" : "fresh");
1811 	spin_unlock(&session->s_cap_lock);
1812 
1813 	if (wake)
1814 		wake_up_session_caps(session, RENEWCAPS);
1815 }
1816 
1817 /*
1818  * send a session close request
1819  */
1820 static int request_close_session(struct ceph_mds_session *session)
1821 {
1822 	struct ceph_msg *msg;
1823 
1824 	dout("request_close_session mds%d state %s seq %lld\n",
1825 	     session->s_mds, ceph_session_state_name(session->s_state),
1826 	     session->s_seq);
1827 	msg = ceph_create_session_msg(CEPH_SESSION_REQUEST_CLOSE,
1828 				      session->s_seq);
1829 	if (!msg)
1830 		return -ENOMEM;
1831 	ceph_con_send(&session->s_con, msg);
1832 	return 1;
1833 }
1834 
1835 /*
1836  * Called with s_mutex held.
1837  */
1838 static int __close_session(struct ceph_mds_client *mdsc,
1839 			 struct ceph_mds_session *session)
1840 {
1841 	if (session->s_state >= CEPH_MDS_SESSION_CLOSING)
1842 		return 0;
1843 	session->s_state = CEPH_MDS_SESSION_CLOSING;
1844 	return request_close_session(session);
1845 }
1846 
1847 static bool drop_negative_children(struct dentry *dentry)
1848 {
1849 	struct dentry *child;
1850 	bool all_negative = true;
1851 
1852 	if (!d_is_dir(dentry))
1853 		goto out;
1854 
1855 	spin_lock(&dentry->d_lock);
1856 	list_for_each_entry(child, &dentry->d_subdirs, d_child) {
1857 		if (d_really_is_positive(child)) {
1858 			all_negative = false;
1859 			break;
1860 		}
1861 	}
1862 	spin_unlock(&dentry->d_lock);
1863 
1864 	if (all_negative)
1865 		shrink_dcache_parent(dentry);
1866 out:
1867 	return all_negative;
1868 }
1869 
1870 /*
1871  * Trim old(er) caps.
1872  *
1873  * Because we can't cache an inode without one or more caps, we do
1874  * this indirectly: if a cap is unused, we prune its aliases, at which
1875  * point the inode will hopefully get dropped to.
1876  *
1877  * Yes, this is a bit sloppy.  Our only real goal here is to respond to
1878  * memory pressure from the MDS, though, so it needn't be perfect.
1879  */
1880 static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
1881 {
1882 	int *remaining = arg;
1883 	struct ceph_inode_info *ci = ceph_inode(inode);
1884 	int used, wanted, oissued, mine;
1885 
1886 	if (*remaining <= 0)
1887 		return -1;
1888 
1889 	spin_lock(&ci->i_ceph_lock);
1890 	mine = cap->issued | cap->implemented;
1891 	used = __ceph_caps_used(ci);
1892 	wanted = __ceph_caps_file_wanted(ci);
1893 	oissued = __ceph_caps_issued_other(ci, cap);
1894 
1895 	dout("trim_caps_cb %p cap %p mine %s oissued %s used %s wanted %s\n",
1896 	     inode, cap, ceph_cap_string(mine), ceph_cap_string(oissued),
1897 	     ceph_cap_string(used), ceph_cap_string(wanted));
1898 	if (cap == ci->i_auth_cap) {
1899 		if (ci->i_dirty_caps || ci->i_flushing_caps ||
1900 		    !list_empty(&ci->i_cap_snaps))
1901 			goto out;
1902 		if ((used | wanted) & CEPH_CAP_ANY_WR)
1903 			goto out;
1904 		/* Note: it's possible that i_filelock_ref becomes non-zero
1905 		 * after dropping auth caps. It doesn't hurt because reply
1906 		 * of lock mds request will re-add auth caps. */
1907 		if (atomic_read(&ci->i_filelock_ref) > 0)
1908 			goto out;
1909 	}
1910 	/* The inode has cached pages, but it's no longer used.
1911 	 * we can safely drop it */
1912 	if (S_ISREG(inode->i_mode) &&
1913 	    wanted == 0 && used == CEPH_CAP_FILE_CACHE &&
1914 	    !(oissued & CEPH_CAP_FILE_CACHE)) {
1915 	  used = 0;
1916 	  oissued = 0;
1917 	}
1918 	if ((used | wanted) & ~oissued & mine)
1919 		goto out;   /* we need these caps */
1920 
1921 	if (oissued) {
1922 		/* we aren't the only cap.. just remove us */
1923 		ceph_remove_cap(cap, true);
1924 		(*remaining)--;
1925 	} else {
1926 		struct dentry *dentry;
1927 		/* try dropping referring dentries */
1928 		spin_unlock(&ci->i_ceph_lock);
1929 		dentry = d_find_any_alias(inode);
1930 		if (dentry && drop_negative_children(dentry)) {
1931 			int count;
1932 			dput(dentry);
1933 			d_prune_aliases(inode);
1934 			count = atomic_read(&inode->i_count);
1935 			if (count == 1)
1936 				(*remaining)--;
1937 			dout("trim_caps_cb %p cap %p pruned, count now %d\n",
1938 			     inode, cap, count);
1939 		} else {
1940 			dput(dentry);
1941 		}
1942 		return 0;
1943 	}
1944 
1945 out:
1946 	spin_unlock(&ci->i_ceph_lock);
1947 	return 0;
1948 }
1949 
1950 /*
1951  * Trim session cap count down to some max number.
1952  */
1953 int ceph_trim_caps(struct ceph_mds_client *mdsc,
1954 		   struct ceph_mds_session *session,
1955 		   int max_caps)
1956 {
1957 	int trim_caps = session->s_nr_caps - max_caps;
1958 
1959 	dout("trim_caps mds%d start: %d / %d, trim %d\n",
1960 	     session->s_mds, session->s_nr_caps, max_caps, trim_caps);
1961 	if (trim_caps > 0) {
1962 		int remaining = trim_caps;
1963 
1964 		ceph_iterate_session_caps(session, trim_caps_cb, &remaining);
1965 		dout("trim_caps mds%d done: %d / %d, trimmed %d\n",
1966 		     session->s_mds, session->s_nr_caps, max_caps,
1967 			trim_caps - remaining);
1968 	}
1969 
1970 	ceph_flush_cap_releases(mdsc, session);
1971 	return 0;
1972 }
1973 
1974 static int check_caps_flush(struct ceph_mds_client *mdsc,
1975 			    u64 want_flush_tid)
1976 {
1977 	int ret = 1;
1978 
1979 	spin_lock(&mdsc->cap_dirty_lock);
1980 	if (!list_empty(&mdsc->cap_flush_list)) {
1981 		struct ceph_cap_flush *cf =
1982 			list_first_entry(&mdsc->cap_flush_list,
1983 					 struct ceph_cap_flush, g_list);
1984 		if (cf->tid <= want_flush_tid) {
1985 			dout("check_caps_flush still flushing tid "
1986 			     "%llu <= %llu\n", cf->tid, want_flush_tid);
1987 			ret = 0;
1988 		}
1989 	}
1990 	spin_unlock(&mdsc->cap_dirty_lock);
1991 	return ret;
1992 }
1993 
1994 /*
1995  * flush all dirty inode data to disk.
1996  *
1997  * returns true if we've flushed through want_flush_tid
1998  */
1999 static void wait_caps_flush(struct ceph_mds_client *mdsc,
2000 			    u64 want_flush_tid)
2001 {
2002 	dout("check_caps_flush want %llu\n", want_flush_tid);
2003 
2004 	wait_event(mdsc->cap_flushing_wq,
2005 		   check_caps_flush(mdsc, want_flush_tid));
2006 
2007 	dout("check_caps_flush ok, flushed thru %llu\n", want_flush_tid);
2008 }
2009 
2010 /*
2011  * called under s_mutex
2012  */
2013 static void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
2014 				   struct ceph_mds_session *session)
2015 {
2016 	struct ceph_msg *msg = NULL;
2017 	struct ceph_mds_cap_release *head;
2018 	struct ceph_mds_cap_item *item;
2019 	struct ceph_osd_client *osdc = &mdsc->fsc->client->osdc;
2020 	struct ceph_cap *cap;
2021 	LIST_HEAD(tmp_list);
2022 	int num_cap_releases;
2023 	__le32	barrier, *cap_barrier;
2024 
2025 	down_read(&osdc->lock);
2026 	barrier = cpu_to_le32(osdc->epoch_barrier);
2027 	up_read(&osdc->lock);
2028 
2029 	spin_lock(&session->s_cap_lock);
2030 again:
2031 	list_splice_init(&session->s_cap_releases, &tmp_list);
2032 	num_cap_releases = session->s_num_cap_releases;
2033 	session->s_num_cap_releases = 0;
2034 	spin_unlock(&session->s_cap_lock);
2035 
2036 	while (!list_empty(&tmp_list)) {
2037 		if (!msg) {
2038 			msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPRELEASE,
2039 					PAGE_SIZE, GFP_NOFS, false);
2040 			if (!msg)
2041 				goto out_err;
2042 			head = msg->front.iov_base;
2043 			head->num = cpu_to_le32(0);
2044 			msg->front.iov_len = sizeof(*head);
2045 
2046 			msg->hdr.version = cpu_to_le16(2);
2047 			msg->hdr.compat_version = cpu_to_le16(1);
2048 		}
2049 
2050 		cap = list_first_entry(&tmp_list, struct ceph_cap,
2051 					session_caps);
2052 		list_del(&cap->session_caps);
2053 		num_cap_releases--;
2054 
2055 		head = msg->front.iov_base;
2056 		put_unaligned_le32(get_unaligned_le32(&head->num) + 1,
2057 				   &head->num);
2058 		item = msg->front.iov_base + msg->front.iov_len;
2059 		item->ino = cpu_to_le64(cap->cap_ino);
2060 		item->cap_id = cpu_to_le64(cap->cap_id);
2061 		item->migrate_seq = cpu_to_le32(cap->mseq);
2062 		item->seq = cpu_to_le32(cap->issue_seq);
2063 		msg->front.iov_len += sizeof(*item);
2064 
2065 		ceph_put_cap(mdsc, cap);
2066 
2067 		if (le32_to_cpu(head->num) == CEPH_CAPS_PER_RELEASE) {
2068 			// Append cap_barrier field
2069 			cap_barrier = msg->front.iov_base + msg->front.iov_len;
2070 			*cap_barrier = barrier;
2071 			msg->front.iov_len += sizeof(*cap_barrier);
2072 
2073 			msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
2074 			dout("send_cap_releases mds%d %p\n", session->s_mds, msg);
2075 			ceph_con_send(&session->s_con, msg);
2076 			msg = NULL;
2077 		}
2078 	}
2079 
2080 	BUG_ON(num_cap_releases != 0);
2081 
2082 	spin_lock(&session->s_cap_lock);
2083 	if (!list_empty(&session->s_cap_releases))
2084 		goto again;
2085 	spin_unlock(&session->s_cap_lock);
2086 
2087 	if (msg) {
2088 		// Append cap_barrier field
2089 		cap_barrier = msg->front.iov_base + msg->front.iov_len;
2090 		*cap_barrier = barrier;
2091 		msg->front.iov_len += sizeof(*cap_barrier);
2092 
2093 		msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
2094 		dout("send_cap_releases mds%d %p\n", session->s_mds, msg);
2095 		ceph_con_send(&session->s_con, msg);
2096 	}
2097 	return;
2098 out_err:
2099 	pr_err("send_cap_releases mds%d, failed to allocate message\n",
2100 		session->s_mds);
2101 	spin_lock(&session->s_cap_lock);
2102 	list_splice(&tmp_list, &session->s_cap_releases);
2103 	session->s_num_cap_releases += num_cap_releases;
2104 	spin_unlock(&session->s_cap_lock);
2105 }
2106 
2107 static void ceph_cap_release_work(struct work_struct *work)
2108 {
2109 	struct ceph_mds_session *session =
2110 		container_of(work, struct ceph_mds_session, s_cap_release_work);
2111 
2112 	mutex_lock(&session->s_mutex);
2113 	if (session->s_state == CEPH_MDS_SESSION_OPEN ||
2114 	    session->s_state == CEPH_MDS_SESSION_HUNG)
2115 		ceph_send_cap_releases(session->s_mdsc, session);
2116 	mutex_unlock(&session->s_mutex);
2117 	ceph_put_mds_session(session);
2118 }
2119 
2120 void ceph_flush_cap_releases(struct ceph_mds_client *mdsc,
2121 		             struct ceph_mds_session *session)
2122 {
2123 	if (mdsc->stopping)
2124 		return;
2125 
2126 	ceph_get_mds_session(session);
2127 	if (queue_work(mdsc->fsc->cap_wq,
2128 		       &session->s_cap_release_work)) {
2129 		dout("cap release work queued\n");
2130 	} else {
2131 		ceph_put_mds_session(session);
2132 		dout("failed to queue cap release work\n");
2133 	}
2134 }
2135 
2136 /*
2137  * caller holds session->s_cap_lock
2138  */
2139 void __ceph_queue_cap_release(struct ceph_mds_session *session,
2140 			      struct ceph_cap *cap)
2141 {
2142 	list_add_tail(&cap->session_caps, &session->s_cap_releases);
2143 	session->s_num_cap_releases++;
2144 
2145 	if (!(session->s_num_cap_releases % CEPH_CAPS_PER_RELEASE))
2146 		ceph_flush_cap_releases(session->s_mdsc, session);
2147 }
2148 
2149 static void ceph_cap_reclaim_work(struct work_struct *work)
2150 {
2151 	struct ceph_mds_client *mdsc =
2152 		container_of(work, struct ceph_mds_client, cap_reclaim_work);
2153 	int ret = ceph_trim_dentries(mdsc);
2154 	if (ret == -EAGAIN)
2155 		ceph_queue_cap_reclaim_work(mdsc);
2156 }
2157 
2158 void ceph_queue_cap_reclaim_work(struct ceph_mds_client *mdsc)
2159 {
2160 	if (mdsc->stopping)
2161 		return;
2162 
2163         if (queue_work(mdsc->fsc->cap_wq, &mdsc->cap_reclaim_work)) {
2164                 dout("caps reclaim work queued\n");
2165         } else {
2166                 dout("failed to queue caps release work\n");
2167         }
2168 }
2169 
2170 void ceph_reclaim_caps_nr(struct ceph_mds_client *mdsc, int nr)
2171 {
2172 	int val;
2173 	if (!nr)
2174 		return;
2175 	val = atomic_add_return(nr, &mdsc->cap_reclaim_pending);
2176 	if ((val % CEPH_CAPS_PER_RELEASE) < nr) {
2177 		atomic_set(&mdsc->cap_reclaim_pending, 0);
2178 		ceph_queue_cap_reclaim_work(mdsc);
2179 	}
2180 }
2181 
2182 /*
2183  * requests
2184  */
2185 
2186 int ceph_alloc_readdir_reply_buffer(struct ceph_mds_request *req,
2187 				    struct inode *dir)
2188 {
2189 	struct ceph_inode_info *ci = ceph_inode(dir);
2190 	struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
2191 	struct ceph_mount_options *opt = req->r_mdsc->fsc->mount_options;
2192 	size_t size = sizeof(struct ceph_mds_reply_dir_entry);
2193 	unsigned int num_entries;
2194 	int order;
2195 
2196 	spin_lock(&ci->i_ceph_lock);
2197 	num_entries = ci->i_files + ci->i_subdirs;
2198 	spin_unlock(&ci->i_ceph_lock);
2199 	num_entries = max(num_entries, 1U);
2200 	num_entries = min(num_entries, opt->max_readdir);
2201 
2202 	order = get_order(size * num_entries);
2203 	while (order >= 0) {
2204 		rinfo->dir_entries = (void*)__get_free_pages(GFP_KERNEL |
2205 							     __GFP_NOWARN |
2206 							     __GFP_ZERO,
2207 							     order);
2208 		if (rinfo->dir_entries)
2209 			break;
2210 		order--;
2211 	}
2212 	if (!rinfo->dir_entries)
2213 		return -ENOMEM;
2214 
2215 	num_entries = (PAGE_SIZE << order) / size;
2216 	num_entries = min(num_entries, opt->max_readdir);
2217 
2218 	rinfo->dir_buf_size = PAGE_SIZE << order;
2219 	req->r_num_caps = num_entries + 1;
2220 	req->r_args.readdir.max_entries = cpu_to_le32(num_entries);
2221 	req->r_args.readdir.max_bytes = cpu_to_le32(opt->max_readdir_bytes);
2222 	return 0;
2223 }
2224 
2225 /*
2226  * Create an mds request.
2227  */
2228 struct ceph_mds_request *
2229 ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode)
2230 {
2231 	struct ceph_mds_request *req;
2232 
2233 	req = kmem_cache_zalloc(ceph_mds_request_cachep, GFP_NOFS);
2234 	if (!req)
2235 		return ERR_PTR(-ENOMEM);
2236 
2237 	mutex_init(&req->r_fill_mutex);
2238 	req->r_mdsc = mdsc;
2239 	req->r_started = jiffies;
2240 	req->r_start_latency = ktime_get();
2241 	req->r_resend_mds = -1;
2242 	INIT_LIST_HEAD(&req->r_unsafe_dir_item);
2243 	INIT_LIST_HEAD(&req->r_unsafe_target_item);
2244 	req->r_fmode = -1;
2245 	kref_init(&req->r_kref);
2246 	RB_CLEAR_NODE(&req->r_node);
2247 	INIT_LIST_HEAD(&req->r_wait);
2248 	init_completion(&req->r_completion);
2249 	init_completion(&req->r_safe_completion);
2250 	INIT_LIST_HEAD(&req->r_unsafe_item);
2251 
2252 	ktime_get_coarse_real_ts64(&req->r_stamp);
2253 
2254 	req->r_op = op;
2255 	req->r_direct_mode = mode;
2256 	return req;
2257 }
2258 
2259 /*
2260  * return oldest (lowest) request, tid in request tree, 0 if none.
2261  *
2262  * called under mdsc->mutex.
2263  */
2264 static struct ceph_mds_request *__get_oldest_req(struct ceph_mds_client *mdsc)
2265 {
2266 	if (RB_EMPTY_ROOT(&mdsc->request_tree))
2267 		return NULL;
2268 	return rb_entry(rb_first(&mdsc->request_tree),
2269 			struct ceph_mds_request, r_node);
2270 }
2271 
2272 static inline  u64 __get_oldest_tid(struct ceph_mds_client *mdsc)
2273 {
2274 	return mdsc->oldest_tid;
2275 }
2276 
2277 /*
2278  * Build a dentry's path.  Allocate on heap; caller must kfree.  Based
2279  * on build_path_from_dentry in fs/cifs/dir.c.
2280  *
2281  * If @stop_on_nosnap, generate path relative to the first non-snapped
2282  * inode.
2283  *
2284  * Encode hidden .snap dirs as a double /, i.e.
2285  *   foo/.snap/bar -> foo//bar
2286  */
2287 char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase,
2288 			   int stop_on_nosnap)
2289 {
2290 	struct dentry *temp;
2291 	char *path;
2292 	int pos;
2293 	unsigned seq;
2294 	u64 base;
2295 
2296 	if (!dentry)
2297 		return ERR_PTR(-EINVAL);
2298 
2299 	path = __getname();
2300 	if (!path)
2301 		return ERR_PTR(-ENOMEM);
2302 retry:
2303 	pos = PATH_MAX - 1;
2304 	path[pos] = '\0';
2305 
2306 	seq = read_seqbegin(&rename_lock);
2307 	rcu_read_lock();
2308 	temp = dentry;
2309 	for (;;) {
2310 		struct inode *inode;
2311 
2312 		spin_lock(&temp->d_lock);
2313 		inode = d_inode(temp);
2314 		if (inode && ceph_snap(inode) == CEPH_SNAPDIR) {
2315 			dout("build_path path+%d: %p SNAPDIR\n",
2316 			     pos, temp);
2317 		} else if (stop_on_nosnap && inode && dentry != temp &&
2318 			   ceph_snap(inode) == CEPH_NOSNAP) {
2319 			spin_unlock(&temp->d_lock);
2320 			pos++; /* get rid of any prepended '/' */
2321 			break;
2322 		} else {
2323 			pos -= temp->d_name.len;
2324 			if (pos < 0) {
2325 				spin_unlock(&temp->d_lock);
2326 				break;
2327 			}
2328 			memcpy(path + pos, temp->d_name.name, temp->d_name.len);
2329 		}
2330 		spin_unlock(&temp->d_lock);
2331 		temp = READ_ONCE(temp->d_parent);
2332 
2333 		/* Are we at the root? */
2334 		if (IS_ROOT(temp))
2335 			break;
2336 
2337 		/* Are we out of buffer? */
2338 		if (--pos < 0)
2339 			break;
2340 
2341 		path[pos] = '/';
2342 	}
2343 	base = ceph_ino(d_inode(temp));
2344 	rcu_read_unlock();
2345 
2346 	if (read_seqretry(&rename_lock, seq))
2347 		goto retry;
2348 
2349 	if (pos < 0) {
2350 		/*
2351 		 * A rename didn't occur, but somehow we didn't end up where
2352 		 * we thought we would. Throw a warning and try again.
2353 		 */
2354 		pr_warn("build_path did not end path lookup where "
2355 			"expected, pos is %d\n", pos);
2356 		goto retry;
2357 	}
2358 
2359 	*pbase = base;
2360 	*plen = PATH_MAX - 1 - pos;
2361 	dout("build_path on %p %d built %llx '%.*s'\n",
2362 	     dentry, d_count(dentry), base, *plen, path + pos);
2363 	return path + pos;
2364 }
2365 
2366 static int build_dentry_path(struct dentry *dentry, struct inode *dir,
2367 			     const char **ppath, int *ppathlen, u64 *pino,
2368 			     bool *pfreepath, bool parent_locked)
2369 {
2370 	char *path;
2371 
2372 	rcu_read_lock();
2373 	if (!dir)
2374 		dir = d_inode_rcu(dentry->d_parent);
2375 	if (dir && parent_locked && ceph_snap(dir) == CEPH_NOSNAP) {
2376 		*pino = ceph_ino(dir);
2377 		rcu_read_unlock();
2378 		*ppath = dentry->d_name.name;
2379 		*ppathlen = dentry->d_name.len;
2380 		return 0;
2381 	}
2382 	rcu_read_unlock();
2383 	path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
2384 	if (IS_ERR(path))
2385 		return PTR_ERR(path);
2386 	*ppath = path;
2387 	*pfreepath = true;
2388 	return 0;
2389 }
2390 
2391 static int build_inode_path(struct inode *inode,
2392 			    const char **ppath, int *ppathlen, u64 *pino,
2393 			    bool *pfreepath)
2394 {
2395 	struct dentry *dentry;
2396 	char *path;
2397 
2398 	if (ceph_snap(inode) == CEPH_NOSNAP) {
2399 		*pino = ceph_ino(inode);
2400 		*ppathlen = 0;
2401 		return 0;
2402 	}
2403 	dentry = d_find_alias(inode);
2404 	path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
2405 	dput(dentry);
2406 	if (IS_ERR(path))
2407 		return PTR_ERR(path);
2408 	*ppath = path;
2409 	*pfreepath = true;
2410 	return 0;
2411 }
2412 
2413 /*
2414  * request arguments may be specified via an inode *, a dentry *, or
2415  * an explicit ino+path.
2416  */
2417 static int set_request_path_attr(struct inode *rinode, struct dentry *rdentry,
2418 				  struct inode *rdiri, const char *rpath,
2419 				  u64 rino, const char **ppath, int *pathlen,
2420 				  u64 *ino, bool *freepath, bool parent_locked)
2421 {
2422 	int r = 0;
2423 
2424 	if (rinode) {
2425 		r = build_inode_path(rinode, ppath, pathlen, ino, freepath);
2426 		dout(" inode %p %llx.%llx\n", rinode, ceph_ino(rinode),
2427 		     ceph_snap(rinode));
2428 	} else if (rdentry) {
2429 		r = build_dentry_path(rdentry, rdiri, ppath, pathlen, ino,
2430 					freepath, parent_locked);
2431 		dout(" dentry %p %llx/%.*s\n", rdentry, *ino, *pathlen,
2432 		     *ppath);
2433 	} else if (rpath || rino) {
2434 		*ino = rino;
2435 		*ppath = rpath;
2436 		*pathlen = rpath ? strlen(rpath) : 0;
2437 		dout(" path %.*s\n", *pathlen, rpath);
2438 	}
2439 
2440 	return r;
2441 }
2442 
2443 static void encode_timestamp_and_gids(void **p,
2444 				      const struct ceph_mds_request *req)
2445 {
2446 	struct ceph_timespec ts;
2447 	int i;
2448 
2449 	ceph_encode_timespec64(&ts, &req->r_stamp);
2450 	ceph_encode_copy(p, &ts, sizeof(ts));
2451 
2452 	/* gid_list */
2453 	ceph_encode_32(p, req->r_cred->group_info->ngroups);
2454 	for (i = 0; i < req->r_cred->group_info->ngroups; i++)
2455 		ceph_encode_64(p, from_kgid(&init_user_ns,
2456 					    req->r_cred->group_info->gid[i]));
2457 }
2458 
2459 /*
2460  * called under mdsc->mutex
2461  */
2462 static struct ceph_msg *create_request_message(struct ceph_mds_session *session,
2463 					       struct ceph_mds_request *req,
2464 					       bool drop_cap_releases)
2465 {
2466 	int mds = session->s_mds;
2467 	struct ceph_mds_client *mdsc = session->s_mdsc;
2468 	struct ceph_msg *msg;
2469 	struct ceph_mds_request_head_old *head;
2470 	const char *path1 = NULL;
2471 	const char *path2 = NULL;
2472 	u64 ino1 = 0, ino2 = 0;
2473 	int pathlen1 = 0, pathlen2 = 0;
2474 	bool freepath1 = false, freepath2 = false;
2475 	int len;
2476 	u16 releases;
2477 	void *p, *end;
2478 	int ret;
2479 	bool legacy = !(session->s_con.peer_features & CEPH_FEATURE_FS_BTIME);
2480 
2481 	ret = set_request_path_attr(req->r_inode, req->r_dentry,
2482 			      req->r_parent, req->r_path1, req->r_ino1.ino,
2483 			      &path1, &pathlen1, &ino1, &freepath1,
2484 			      test_bit(CEPH_MDS_R_PARENT_LOCKED,
2485 					&req->r_req_flags));
2486 	if (ret < 0) {
2487 		msg = ERR_PTR(ret);
2488 		goto out;
2489 	}
2490 
2491 	/* If r_old_dentry is set, then assume that its parent is locked */
2492 	ret = set_request_path_attr(NULL, req->r_old_dentry,
2493 			      req->r_old_dentry_dir,
2494 			      req->r_path2, req->r_ino2.ino,
2495 			      &path2, &pathlen2, &ino2, &freepath2, true);
2496 	if (ret < 0) {
2497 		msg = ERR_PTR(ret);
2498 		goto out_free1;
2499 	}
2500 
2501 	len = legacy ? sizeof(*head) : sizeof(struct ceph_mds_request_head);
2502 	len += pathlen1 + pathlen2 + 2*(1 + sizeof(u32) + sizeof(u64)) +
2503 		sizeof(struct ceph_timespec);
2504 	len += sizeof(u32) + (sizeof(u64) * req->r_cred->group_info->ngroups);
2505 
2506 	/* calculate (max) length for cap releases */
2507 	len += sizeof(struct ceph_mds_request_release) *
2508 		(!!req->r_inode_drop + !!req->r_dentry_drop +
2509 		 !!req->r_old_inode_drop + !!req->r_old_dentry_drop);
2510 
2511 	if (req->r_dentry_drop)
2512 		len += pathlen1;
2513 	if (req->r_old_dentry_drop)
2514 		len += pathlen2;
2515 
2516 	msg = ceph_msg_new2(CEPH_MSG_CLIENT_REQUEST, len, 1, GFP_NOFS, false);
2517 	if (!msg) {
2518 		msg = ERR_PTR(-ENOMEM);
2519 		goto out_free2;
2520 	}
2521 
2522 	msg->hdr.tid = cpu_to_le64(req->r_tid);
2523 
2524 	/*
2525 	 * The old ceph_mds_request_head didn't contain a version field, and
2526 	 * one was added when we moved the message version from 3->4.
2527 	 */
2528 	if (legacy) {
2529 		msg->hdr.version = cpu_to_le16(3);
2530 		head = msg->front.iov_base;
2531 		p = msg->front.iov_base + sizeof(*head);
2532 	} else {
2533 		struct ceph_mds_request_head *new_head = msg->front.iov_base;
2534 
2535 		msg->hdr.version = cpu_to_le16(4);
2536 		new_head->version = cpu_to_le16(CEPH_MDS_REQUEST_HEAD_VERSION);
2537 		head = (struct ceph_mds_request_head_old *)&new_head->oldest_client_tid;
2538 		p = msg->front.iov_base + sizeof(*new_head);
2539 	}
2540 
2541 	end = msg->front.iov_base + msg->front.iov_len;
2542 
2543 	head->mdsmap_epoch = cpu_to_le32(mdsc->mdsmap->m_epoch);
2544 	head->op = cpu_to_le32(req->r_op);
2545 	head->caller_uid = cpu_to_le32(from_kuid(&init_user_ns,
2546 						 req->r_cred->fsuid));
2547 	head->caller_gid = cpu_to_le32(from_kgid(&init_user_ns,
2548 						 req->r_cred->fsgid));
2549 	head->ino = cpu_to_le64(req->r_deleg_ino);
2550 	head->args = req->r_args;
2551 
2552 	ceph_encode_filepath(&p, end, ino1, path1);
2553 	ceph_encode_filepath(&p, end, ino2, path2);
2554 
2555 	/* make note of release offset, in case we need to replay */
2556 	req->r_request_release_offset = p - msg->front.iov_base;
2557 
2558 	/* cap releases */
2559 	releases = 0;
2560 	if (req->r_inode_drop)
2561 		releases += ceph_encode_inode_release(&p,
2562 		      req->r_inode ? req->r_inode : d_inode(req->r_dentry),
2563 		      mds, req->r_inode_drop, req->r_inode_unless,
2564 		      req->r_op == CEPH_MDS_OP_READDIR);
2565 	if (req->r_dentry_drop)
2566 		releases += ceph_encode_dentry_release(&p, req->r_dentry,
2567 				req->r_parent, mds, req->r_dentry_drop,
2568 				req->r_dentry_unless);
2569 	if (req->r_old_dentry_drop)
2570 		releases += ceph_encode_dentry_release(&p, req->r_old_dentry,
2571 				req->r_old_dentry_dir, mds,
2572 				req->r_old_dentry_drop,
2573 				req->r_old_dentry_unless);
2574 	if (req->r_old_inode_drop)
2575 		releases += ceph_encode_inode_release(&p,
2576 		      d_inode(req->r_old_dentry),
2577 		      mds, req->r_old_inode_drop, req->r_old_inode_unless, 0);
2578 
2579 	if (drop_cap_releases) {
2580 		releases = 0;
2581 		p = msg->front.iov_base + req->r_request_release_offset;
2582 	}
2583 
2584 	head->num_releases = cpu_to_le16(releases);
2585 
2586 	encode_timestamp_and_gids(&p, req);
2587 
2588 	if (WARN_ON_ONCE(p > end)) {
2589 		ceph_msg_put(msg);
2590 		msg = ERR_PTR(-ERANGE);
2591 		goto out_free2;
2592 	}
2593 
2594 	msg->front.iov_len = p - msg->front.iov_base;
2595 	msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
2596 
2597 	if (req->r_pagelist) {
2598 		struct ceph_pagelist *pagelist = req->r_pagelist;
2599 		ceph_msg_data_add_pagelist(msg, pagelist);
2600 		msg->hdr.data_len = cpu_to_le32(pagelist->length);
2601 	} else {
2602 		msg->hdr.data_len = 0;
2603 	}
2604 
2605 	msg->hdr.data_off = cpu_to_le16(0);
2606 
2607 out_free2:
2608 	if (freepath2)
2609 		ceph_mdsc_free_path((char *)path2, pathlen2);
2610 out_free1:
2611 	if (freepath1)
2612 		ceph_mdsc_free_path((char *)path1, pathlen1);
2613 out:
2614 	return msg;
2615 }
2616 
2617 /*
2618  * called under mdsc->mutex if error, under no mutex if
2619  * success.
2620  */
2621 static void complete_request(struct ceph_mds_client *mdsc,
2622 			     struct ceph_mds_request *req)
2623 {
2624 	req->r_end_latency = ktime_get();
2625 
2626 	if (req->r_callback)
2627 		req->r_callback(mdsc, req);
2628 	complete_all(&req->r_completion);
2629 }
2630 
2631 static struct ceph_mds_request_head_old *
2632 find_old_request_head(void *p, u64 features)
2633 {
2634 	bool legacy = !(features & CEPH_FEATURE_FS_BTIME);
2635 	struct ceph_mds_request_head *new_head;
2636 
2637 	if (legacy)
2638 		return (struct ceph_mds_request_head_old *)p;
2639 	new_head = (struct ceph_mds_request_head *)p;
2640 	return (struct ceph_mds_request_head_old *)&new_head->oldest_client_tid;
2641 }
2642 
2643 /*
2644  * called under mdsc->mutex
2645  */
2646 static int __prepare_send_request(struct ceph_mds_session *session,
2647 				  struct ceph_mds_request *req,
2648 				  bool drop_cap_releases)
2649 {
2650 	int mds = session->s_mds;
2651 	struct ceph_mds_client *mdsc = session->s_mdsc;
2652 	struct ceph_mds_request_head_old *rhead;
2653 	struct ceph_msg *msg;
2654 	int flags = 0;
2655 
2656 	req->r_attempts++;
2657 	if (req->r_inode) {
2658 		struct ceph_cap *cap =
2659 			ceph_get_cap_for_mds(ceph_inode(req->r_inode), mds);
2660 
2661 		if (cap)
2662 			req->r_sent_on_mseq = cap->mseq;
2663 		else
2664 			req->r_sent_on_mseq = -1;
2665 	}
2666 	dout("prepare_send_request %p tid %lld %s (attempt %d)\n", req,
2667 	     req->r_tid, ceph_mds_op_name(req->r_op), req->r_attempts);
2668 
2669 	if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
2670 		void *p;
2671 
2672 		/*
2673 		 * Replay.  Do not regenerate message (and rebuild
2674 		 * paths, etc.); just use the original message.
2675 		 * Rebuilding paths will break for renames because
2676 		 * d_move mangles the src name.
2677 		 */
2678 		msg = req->r_request;
2679 		rhead = find_old_request_head(msg->front.iov_base,
2680 					      session->s_con.peer_features);
2681 
2682 		flags = le32_to_cpu(rhead->flags);
2683 		flags |= CEPH_MDS_FLAG_REPLAY;
2684 		rhead->flags = cpu_to_le32(flags);
2685 
2686 		if (req->r_target_inode)
2687 			rhead->ino = cpu_to_le64(ceph_ino(req->r_target_inode));
2688 
2689 		rhead->num_retry = req->r_attempts - 1;
2690 
2691 		/* remove cap/dentry releases from message */
2692 		rhead->num_releases = 0;
2693 
2694 		p = msg->front.iov_base + req->r_request_release_offset;
2695 		encode_timestamp_and_gids(&p, req);
2696 
2697 		msg->front.iov_len = p - msg->front.iov_base;
2698 		msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
2699 		return 0;
2700 	}
2701 
2702 	if (req->r_request) {
2703 		ceph_msg_put(req->r_request);
2704 		req->r_request = NULL;
2705 	}
2706 	msg = create_request_message(session, req, drop_cap_releases);
2707 	if (IS_ERR(msg)) {
2708 		req->r_err = PTR_ERR(msg);
2709 		return PTR_ERR(msg);
2710 	}
2711 	req->r_request = msg;
2712 
2713 	rhead = find_old_request_head(msg->front.iov_base,
2714 				      session->s_con.peer_features);
2715 	rhead->oldest_client_tid = cpu_to_le64(__get_oldest_tid(mdsc));
2716 	if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags))
2717 		flags |= CEPH_MDS_FLAG_REPLAY;
2718 	if (test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags))
2719 		flags |= CEPH_MDS_FLAG_ASYNC;
2720 	if (req->r_parent)
2721 		flags |= CEPH_MDS_FLAG_WANT_DENTRY;
2722 	rhead->flags = cpu_to_le32(flags);
2723 	rhead->num_fwd = req->r_num_fwd;
2724 	rhead->num_retry = req->r_attempts - 1;
2725 
2726 	dout(" r_parent = %p\n", req->r_parent);
2727 	return 0;
2728 }
2729 
2730 /*
2731  * called under mdsc->mutex
2732  */
2733 static int __send_request(struct ceph_mds_session *session,
2734 			  struct ceph_mds_request *req,
2735 			  bool drop_cap_releases)
2736 {
2737 	int err;
2738 
2739 	err = __prepare_send_request(session, req, drop_cap_releases);
2740 	if (!err) {
2741 		ceph_msg_get(req->r_request);
2742 		ceph_con_send(&session->s_con, req->r_request);
2743 	}
2744 
2745 	return err;
2746 }
2747 
2748 /*
2749  * send request, or put it on the appropriate wait list.
2750  */
2751 static void __do_request(struct ceph_mds_client *mdsc,
2752 			struct ceph_mds_request *req)
2753 {
2754 	struct ceph_mds_session *session = NULL;
2755 	int mds = -1;
2756 	int err = 0;
2757 	bool random;
2758 
2759 	if (req->r_err || test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags)) {
2760 		if (test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags))
2761 			__unregister_request(mdsc, req);
2762 		return;
2763 	}
2764 
2765 	if (req->r_timeout &&
2766 	    time_after_eq(jiffies, req->r_started + req->r_timeout)) {
2767 		dout("do_request timed out\n");
2768 		err = -ETIMEDOUT;
2769 		goto finish;
2770 	}
2771 	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_SHUTDOWN) {
2772 		dout("do_request forced umount\n");
2773 		err = -EIO;
2774 		goto finish;
2775 	}
2776 	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_MOUNTING) {
2777 		if (mdsc->mdsmap_err) {
2778 			err = mdsc->mdsmap_err;
2779 			dout("do_request mdsmap err %d\n", err);
2780 			goto finish;
2781 		}
2782 		if (mdsc->mdsmap->m_epoch == 0) {
2783 			dout("do_request no mdsmap, waiting for map\n");
2784 			list_add(&req->r_wait, &mdsc->waiting_for_map);
2785 			return;
2786 		}
2787 		if (!(mdsc->fsc->mount_options->flags &
2788 		      CEPH_MOUNT_OPT_MOUNTWAIT) &&
2789 		    !ceph_mdsmap_is_cluster_available(mdsc->mdsmap)) {
2790 			err = -EHOSTUNREACH;
2791 			goto finish;
2792 		}
2793 	}
2794 
2795 	put_request_session(req);
2796 
2797 	mds = __choose_mds(mdsc, req, &random);
2798 	if (mds < 0 ||
2799 	    ceph_mdsmap_get_state(mdsc->mdsmap, mds) < CEPH_MDS_STATE_ACTIVE) {
2800 		if (test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags)) {
2801 			err = -EJUKEBOX;
2802 			goto finish;
2803 		}
2804 		dout("do_request no mds or not active, waiting for map\n");
2805 		list_add(&req->r_wait, &mdsc->waiting_for_map);
2806 		return;
2807 	}
2808 
2809 	/* get, open session */
2810 	session = __ceph_lookup_mds_session(mdsc, mds);
2811 	if (!session) {
2812 		session = register_session(mdsc, mds);
2813 		if (IS_ERR(session)) {
2814 			err = PTR_ERR(session);
2815 			goto finish;
2816 		}
2817 	}
2818 	req->r_session = ceph_get_mds_session(session);
2819 
2820 	dout("do_request mds%d session %p state %s\n", mds, session,
2821 	     ceph_session_state_name(session->s_state));
2822 	if (session->s_state != CEPH_MDS_SESSION_OPEN &&
2823 	    session->s_state != CEPH_MDS_SESSION_HUNG) {
2824 		/*
2825 		 * We cannot queue async requests since the caps and delegated
2826 		 * inodes are bound to the session. Just return -EJUKEBOX and
2827 		 * let the caller retry a sync request in that case.
2828 		 */
2829 		if (test_bit(CEPH_MDS_R_ASYNC, &req->r_req_flags)) {
2830 			err = -EJUKEBOX;
2831 			goto out_session;
2832 		}
2833 
2834 		/*
2835 		 * If the session has been REJECTED, then return a hard error,
2836 		 * unless it's a CLEANRECOVER mount, in which case we'll queue
2837 		 * it to the mdsc queue.
2838 		 */
2839 		if (session->s_state == CEPH_MDS_SESSION_REJECTED) {
2840 			if (ceph_test_mount_opt(mdsc->fsc, CLEANRECOVER))
2841 				list_add(&req->r_wait, &mdsc->waiting_for_map);
2842 			else
2843 				err = -EACCES;
2844 			goto out_session;
2845 		}
2846 
2847 		if (session->s_state == CEPH_MDS_SESSION_NEW ||
2848 		    session->s_state == CEPH_MDS_SESSION_CLOSING) {
2849 			err = __open_session(mdsc, session);
2850 			if (err)
2851 				goto out_session;
2852 			/* retry the same mds later */
2853 			if (random)
2854 				req->r_resend_mds = mds;
2855 		}
2856 		list_add(&req->r_wait, &session->s_waiting);
2857 		goto out_session;
2858 	}
2859 
2860 	/* send request */
2861 	req->r_resend_mds = -1;   /* forget any previous mds hint */
2862 
2863 	if (req->r_request_started == 0)   /* note request start time */
2864 		req->r_request_started = jiffies;
2865 
2866 	err = __send_request(session, req, false);
2867 
2868 out_session:
2869 	ceph_put_mds_session(session);
2870 finish:
2871 	if (err) {
2872 		dout("__do_request early error %d\n", err);
2873 		req->r_err = err;
2874 		complete_request(mdsc, req);
2875 		__unregister_request(mdsc, req);
2876 	}
2877 	return;
2878 }
2879 
2880 /*
2881  * called under mdsc->mutex
2882  */
2883 static void __wake_requests(struct ceph_mds_client *mdsc,
2884 			    struct list_head *head)
2885 {
2886 	struct ceph_mds_request *req;
2887 	LIST_HEAD(tmp_list);
2888 
2889 	list_splice_init(head, &tmp_list);
2890 
2891 	while (!list_empty(&tmp_list)) {
2892 		req = list_entry(tmp_list.next,
2893 				 struct ceph_mds_request, r_wait);
2894 		list_del_init(&req->r_wait);
2895 		dout(" wake request %p tid %llu\n", req, req->r_tid);
2896 		__do_request(mdsc, req);
2897 	}
2898 }
2899 
2900 /*
2901  * Wake up threads with requests pending for @mds, so that they can
2902  * resubmit their requests to a possibly different mds.
2903  */
2904 static void kick_requests(struct ceph_mds_client *mdsc, int mds)
2905 {
2906 	struct ceph_mds_request *req;
2907 	struct rb_node *p = rb_first(&mdsc->request_tree);
2908 
2909 	dout("kick_requests mds%d\n", mds);
2910 	while (p) {
2911 		req = rb_entry(p, struct ceph_mds_request, r_node);
2912 		p = rb_next(p);
2913 		if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags))
2914 			continue;
2915 		if (req->r_attempts > 0)
2916 			continue; /* only new requests */
2917 		if (req->r_session &&
2918 		    req->r_session->s_mds == mds) {
2919 			dout(" kicking tid %llu\n", req->r_tid);
2920 			list_del_init(&req->r_wait);
2921 			__do_request(mdsc, req);
2922 		}
2923 	}
2924 }
2925 
2926 int ceph_mdsc_submit_request(struct ceph_mds_client *mdsc, struct inode *dir,
2927 			      struct ceph_mds_request *req)
2928 {
2929 	int err = 0;
2930 
2931 	/* take CAP_PIN refs for r_inode, r_parent, r_old_dentry */
2932 	if (req->r_inode)
2933 		ceph_get_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
2934 	if (req->r_parent) {
2935 		struct ceph_inode_info *ci = ceph_inode(req->r_parent);
2936 		int fmode = (req->r_op & CEPH_MDS_OP_WRITE) ?
2937 			    CEPH_FILE_MODE_WR : CEPH_FILE_MODE_RD;
2938 		spin_lock(&ci->i_ceph_lock);
2939 		ceph_take_cap_refs(ci, CEPH_CAP_PIN, false);
2940 		__ceph_touch_fmode(ci, mdsc, fmode);
2941 		spin_unlock(&ci->i_ceph_lock);
2942 	}
2943 	if (req->r_old_dentry_dir)
2944 		ceph_get_cap_refs(ceph_inode(req->r_old_dentry_dir),
2945 				  CEPH_CAP_PIN);
2946 
2947 	if (req->r_inode) {
2948 		err = ceph_wait_on_async_create(req->r_inode);
2949 		if (err) {
2950 			dout("%s: wait for async create returned: %d\n",
2951 			     __func__, err);
2952 			return err;
2953 		}
2954 	}
2955 
2956 	if (!err && req->r_old_inode) {
2957 		err = ceph_wait_on_async_create(req->r_old_inode);
2958 		if (err) {
2959 			dout("%s: wait for async create returned: %d\n",
2960 			     __func__, err);
2961 			return err;
2962 		}
2963 	}
2964 
2965 	dout("submit_request on %p for inode %p\n", req, dir);
2966 	mutex_lock(&mdsc->mutex);
2967 	__register_request(mdsc, req, dir);
2968 	__do_request(mdsc, req);
2969 	err = req->r_err;
2970 	mutex_unlock(&mdsc->mutex);
2971 	return err;
2972 }
2973 
2974 int ceph_mdsc_wait_request(struct ceph_mds_client *mdsc,
2975 			   struct ceph_mds_request *req,
2976 			   ceph_mds_request_wait_callback_t wait_func)
2977 {
2978 	int err;
2979 
2980 	/* wait */
2981 	dout("do_request waiting\n");
2982 	if (wait_func) {
2983 		err = wait_func(mdsc, req);
2984 	} else {
2985 		long timeleft = wait_for_completion_killable_timeout(
2986 					&req->r_completion,
2987 					ceph_timeout_jiffies(req->r_timeout));
2988 		if (timeleft > 0)
2989 			err = 0;
2990 		else if (!timeleft)
2991 			err = -ETIMEDOUT;  /* timed out */
2992 		else
2993 			err = timeleft;  /* killed */
2994 	}
2995 	dout("do_request waited, got %d\n", err);
2996 	mutex_lock(&mdsc->mutex);
2997 
2998 	/* only abort if we didn't race with a real reply */
2999 	if (test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags)) {
3000 		err = le32_to_cpu(req->r_reply_info.head->result);
3001 	} else if (err < 0) {
3002 		dout("aborted request %lld with %d\n", req->r_tid, err);
3003 
3004 		/*
3005 		 * ensure we aren't running concurrently with
3006 		 * ceph_fill_trace or ceph_readdir_prepopulate, which
3007 		 * rely on locks (dir mutex) held by our caller.
3008 		 */
3009 		mutex_lock(&req->r_fill_mutex);
3010 		req->r_err = err;
3011 		set_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags);
3012 		mutex_unlock(&req->r_fill_mutex);
3013 
3014 		if (req->r_parent &&
3015 		    (req->r_op & CEPH_MDS_OP_WRITE))
3016 			ceph_invalidate_dir_request(req);
3017 	} else {
3018 		err = req->r_err;
3019 	}
3020 
3021 	mutex_unlock(&mdsc->mutex);
3022 	return err;
3023 }
3024 
3025 /*
3026  * Synchrously perform an mds request.  Take care of all of the
3027  * session setup, forwarding, retry details.
3028  */
3029 int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
3030 			 struct inode *dir,
3031 			 struct ceph_mds_request *req)
3032 {
3033 	int err;
3034 
3035 	dout("do_request on %p\n", req);
3036 
3037 	/* issue */
3038 	err = ceph_mdsc_submit_request(mdsc, dir, req);
3039 	if (!err)
3040 		err = ceph_mdsc_wait_request(mdsc, req, NULL);
3041 	dout("do_request %p done, result %d\n", req, err);
3042 	return err;
3043 }
3044 
3045 /*
3046  * Invalidate dir's completeness, dentry lease state on an aborted MDS
3047  * namespace request.
3048  */
3049 void ceph_invalidate_dir_request(struct ceph_mds_request *req)
3050 {
3051 	struct inode *dir = req->r_parent;
3052 	struct inode *old_dir = req->r_old_dentry_dir;
3053 
3054 	dout("invalidate_dir_request %p %p (complete, lease(s))\n", dir, old_dir);
3055 
3056 	ceph_dir_clear_complete(dir);
3057 	if (old_dir)
3058 		ceph_dir_clear_complete(old_dir);
3059 	if (req->r_dentry)
3060 		ceph_invalidate_dentry_lease(req->r_dentry);
3061 	if (req->r_old_dentry)
3062 		ceph_invalidate_dentry_lease(req->r_old_dentry);
3063 }
3064 
3065 /*
3066  * Handle mds reply.
3067  *
3068  * We take the session mutex and parse and process the reply immediately.
3069  * This preserves the logical ordering of replies, capabilities, etc., sent
3070  * by the MDS as they are applied to our local cache.
3071  */
3072 static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
3073 {
3074 	struct ceph_mds_client *mdsc = session->s_mdsc;
3075 	struct ceph_mds_request *req;
3076 	struct ceph_mds_reply_head *head = msg->front.iov_base;
3077 	struct ceph_mds_reply_info_parsed *rinfo;  /* parsed reply info */
3078 	struct ceph_snap_realm *realm;
3079 	u64 tid;
3080 	int err, result;
3081 	int mds = session->s_mds;
3082 
3083 	if (msg->front.iov_len < sizeof(*head)) {
3084 		pr_err("mdsc_handle_reply got corrupt (short) reply\n");
3085 		ceph_msg_dump(msg);
3086 		return;
3087 	}
3088 
3089 	/* get request, session */
3090 	tid = le64_to_cpu(msg->hdr.tid);
3091 	mutex_lock(&mdsc->mutex);
3092 	req = lookup_get_request(mdsc, tid);
3093 	if (!req) {
3094 		dout("handle_reply on unknown tid %llu\n", tid);
3095 		mutex_unlock(&mdsc->mutex);
3096 		return;
3097 	}
3098 	dout("handle_reply %p\n", req);
3099 
3100 	/* correct session? */
3101 	if (req->r_session != session) {
3102 		pr_err("mdsc_handle_reply got %llu on session mds%d"
3103 		       " not mds%d\n", tid, session->s_mds,
3104 		       req->r_session ? req->r_session->s_mds : -1);
3105 		mutex_unlock(&mdsc->mutex);
3106 		goto out;
3107 	}
3108 
3109 	/* dup? */
3110 	if ((test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags) && !head->safe) ||
3111 	    (test_bit(CEPH_MDS_R_GOT_SAFE, &req->r_req_flags) && head->safe)) {
3112 		pr_warn("got a dup %s reply on %llu from mds%d\n",
3113 			   head->safe ? "safe" : "unsafe", tid, mds);
3114 		mutex_unlock(&mdsc->mutex);
3115 		goto out;
3116 	}
3117 	if (test_bit(CEPH_MDS_R_GOT_SAFE, &req->r_req_flags)) {
3118 		pr_warn("got unsafe after safe on %llu from mds%d\n",
3119 			   tid, mds);
3120 		mutex_unlock(&mdsc->mutex);
3121 		goto out;
3122 	}
3123 
3124 	result = le32_to_cpu(head->result);
3125 
3126 	if (head->safe) {
3127 		set_bit(CEPH_MDS_R_GOT_SAFE, &req->r_req_flags);
3128 		__unregister_request(mdsc, req);
3129 
3130 		/* last request during umount? */
3131 		if (mdsc->stopping && !__get_oldest_req(mdsc))
3132 			complete_all(&mdsc->safe_umount_waiters);
3133 
3134 		if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
3135 			/*
3136 			 * We already handled the unsafe response, now do the
3137 			 * cleanup.  No need to examine the response; the MDS
3138 			 * doesn't include any result info in the safe
3139 			 * response.  And even if it did, there is nothing
3140 			 * useful we could do with a revised return value.
3141 			 */
3142 			dout("got safe reply %llu, mds%d\n", tid, mds);
3143 
3144 			mutex_unlock(&mdsc->mutex);
3145 			goto out;
3146 		}
3147 	} else {
3148 		set_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags);
3149 		list_add_tail(&req->r_unsafe_item, &req->r_session->s_unsafe);
3150 	}
3151 
3152 	dout("handle_reply tid %lld result %d\n", tid, result);
3153 	rinfo = &req->r_reply_info;
3154 	if (test_bit(CEPHFS_FEATURE_REPLY_ENCODING, &session->s_features))
3155 		err = parse_reply_info(session, msg, rinfo, (u64)-1);
3156 	else
3157 		err = parse_reply_info(session, msg, rinfo, session->s_con.peer_features);
3158 	mutex_unlock(&mdsc->mutex);
3159 
3160 	/* Must find target inode outside of mutexes to avoid deadlocks */
3161 	if ((err >= 0) && rinfo->head->is_target) {
3162 		struct inode *in;
3163 		struct ceph_vino tvino = {
3164 			.ino  = le64_to_cpu(rinfo->targeti.in->ino),
3165 			.snap = le64_to_cpu(rinfo->targeti.in->snapid)
3166 		};
3167 
3168 		in = ceph_get_inode(mdsc->fsc->sb, tvino);
3169 		if (IS_ERR(in)) {
3170 			err = PTR_ERR(in);
3171 			mutex_lock(&session->s_mutex);
3172 			goto out_err;
3173 		}
3174 		req->r_target_inode = in;
3175 	}
3176 
3177 	mutex_lock(&session->s_mutex);
3178 	if (err < 0) {
3179 		pr_err("mdsc_handle_reply got corrupt reply mds%d(tid:%lld)\n", mds, tid);
3180 		ceph_msg_dump(msg);
3181 		goto out_err;
3182 	}
3183 
3184 	/* snap trace */
3185 	realm = NULL;
3186 	if (rinfo->snapblob_len) {
3187 		down_write(&mdsc->snap_rwsem);
3188 		ceph_update_snap_trace(mdsc, rinfo->snapblob,
3189 				rinfo->snapblob + rinfo->snapblob_len,
3190 				le32_to_cpu(head->op) == CEPH_MDS_OP_RMSNAP,
3191 				&realm);
3192 		downgrade_write(&mdsc->snap_rwsem);
3193 	} else {
3194 		down_read(&mdsc->snap_rwsem);
3195 	}
3196 
3197 	/* insert trace into our cache */
3198 	mutex_lock(&req->r_fill_mutex);
3199 	current->journal_info = req;
3200 	err = ceph_fill_trace(mdsc->fsc->sb, req);
3201 	if (err == 0) {
3202 		if (result == 0 && (req->r_op == CEPH_MDS_OP_READDIR ||
3203 				    req->r_op == CEPH_MDS_OP_LSSNAP))
3204 			ceph_readdir_prepopulate(req, req->r_session);
3205 	}
3206 	current->journal_info = NULL;
3207 	mutex_unlock(&req->r_fill_mutex);
3208 
3209 	up_read(&mdsc->snap_rwsem);
3210 	if (realm)
3211 		ceph_put_snap_realm(mdsc, realm);
3212 
3213 	if (err == 0) {
3214 		if (req->r_target_inode &&
3215 		    test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags)) {
3216 			struct ceph_inode_info *ci =
3217 				ceph_inode(req->r_target_inode);
3218 			spin_lock(&ci->i_unsafe_lock);
3219 			list_add_tail(&req->r_unsafe_target_item,
3220 				      &ci->i_unsafe_iops);
3221 			spin_unlock(&ci->i_unsafe_lock);
3222 		}
3223 
3224 		ceph_unreserve_caps(mdsc, &req->r_caps_reservation);
3225 	}
3226 out_err:
3227 	mutex_lock(&mdsc->mutex);
3228 	if (!test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags)) {
3229 		if (err) {
3230 			req->r_err = err;
3231 		} else {
3232 			req->r_reply =  ceph_msg_get(msg);
3233 			set_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags);
3234 		}
3235 	} else {
3236 		dout("reply arrived after request %lld was aborted\n", tid);
3237 	}
3238 	mutex_unlock(&mdsc->mutex);
3239 
3240 	mutex_unlock(&session->s_mutex);
3241 
3242 	/* kick calling process */
3243 	complete_request(mdsc, req);
3244 
3245 	ceph_update_metadata_metrics(&mdsc->metric, req->r_start_latency,
3246 				     req->r_end_latency, err);
3247 out:
3248 	ceph_mdsc_put_request(req);
3249 	return;
3250 }
3251 
3252 
3253 
3254 /*
3255  * handle mds notification that our request has been forwarded.
3256  */
3257 static void handle_forward(struct ceph_mds_client *mdsc,
3258 			   struct ceph_mds_session *session,
3259 			   struct ceph_msg *msg)
3260 {
3261 	struct ceph_mds_request *req;
3262 	u64 tid = le64_to_cpu(msg->hdr.tid);
3263 	u32 next_mds;
3264 	u32 fwd_seq;
3265 	int err = -EINVAL;
3266 	void *p = msg->front.iov_base;
3267 	void *end = p + msg->front.iov_len;
3268 
3269 	ceph_decode_need(&p, end, 2*sizeof(u32), bad);
3270 	next_mds = ceph_decode_32(&p);
3271 	fwd_seq = ceph_decode_32(&p);
3272 
3273 	mutex_lock(&mdsc->mutex);
3274 	req = lookup_get_request(mdsc, tid);
3275 	if (!req) {
3276 		dout("forward tid %llu to mds%d - req dne\n", tid, next_mds);
3277 		goto out;  /* dup reply? */
3278 	}
3279 
3280 	if (test_bit(CEPH_MDS_R_ABORTED, &req->r_req_flags)) {
3281 		dout("forward tid %llu aborted, unregistering\n", tid);
3282 		__unregister_request(mdsc, req);
3283 	} else if (fwd_seq <= req->r_num_fwd) {
3284 		dout("forward tid %llu to mds%d - old seq %d <= %d\n",
3285 		     tid, next_mds, req->r_num_fwd, fwd_seq);
3286 	} else {
3287 		/* resend. forward race not possible; mds would drop */
3288 		dout("forward tid %llu to mds%d (we resend)\n", tid, next_mds);
3289 		BUG_ON(req->r_err);
3290 		BUG_ON(test_bit(CEPH_MDS_R_GOT_RESULT, &req->r_req_flags));
3291 		req->r_attempts = 0;
3292 		req->r_num_fwd = fwd_seq;
3293 		req->r_resend_mds = next_mds;
3294 		put_request_session(req);
3295 		__do_request(mdsc, req);
3296 	}
3297 	ceph_mdsc_put_request(req);
3298 out:
3299 	mutex_unlock(&mdsc->mutex);
3300 	return;
3301 
3302 bad:
3303 	pr_err("mdsc_handle_forward decode error err=%d\n", err);
3304 }
3305 
3306 static int __decode_session_metadata(void **p, void *end,
3307 				     bool *blocklisted)
3308 {
3309 	/* map<string,string> */
3310 	u32 n;
3311 	bool err_str;
3312 	ceph_decode_32_safe(p, end, n, bad);
3313 	while (n-- > 0) {
3314 		u32 len;
3315 		ceph_decode_32_safe(p, end, len, bad);
3316 		ceph_decode_need(p, end, len, bad);
3317 		err_str = !strncmp(*p, "error_string", len);
3318 		*p += len;
3319 		ceph_decode_32_safe(p, end, len, bad);
3320 		ceph_decode_need(p, end, len, bad);
3321 		/*
3322 		 * Match "blocklisted (blacklisted)" from newer MDSes,
3323 		 * or "blacklisted" from older MDSes.
3324 		 */
3325 		if (err_str && strnstr(*p, "blacklisted", len))
3326 			*blocklisted = true;
3327 		*p += len;
3328 	}
3329 	return 0;
3330 bad:
3331 	return -1;
3332 }
3333 
3334 /*
3335  * handle a mds session control message
3336  */
3337 static void handle_session(struct ceph_mds_session *session,
3338 			   struct ceph_msg *msg)
3339 {
3340 	struct ceph_mds_client *mdsc = session->s_mdsc;
3341 	int mds = session->s_mds;
3342 	int msg_version = le16_to_cpu(msg->hdr.version);
3343 	void *p = msg->front.iov_base;
3344 	void *end = p + msg->front.iov_len;
3345 	struct ceph_mds_session_head *h;
3346 	u32 op;
3347 	u64 seq, features = 0;
3348 	int wake = 0;
3349 	bool blocklisted = false;
3350 
3351 	/* decode */
3352 	ceph_decode_need(&p, end, sizeof(*h), bad);
3353 	h = p;
3354 	p += sizeof(*h);
3355 
3356 	op = le32_to_cpu(h->op);
3357 	seq = le64_to_cpu(h->seq);
3358 
3359 	if (msg_version >= 3) {
3360 		u32 len;
3361 		/* version >= 2 and < 5, decode metadata, skip otherwise
3362 		 * as it's handled via flags.
3363 		 */
3364 		if (msg_version >= 5)
3365 			ceph_decode_skip_map(&p, end, string, string, bad);
3366 		else if (__decode_session_metadata(&p, end, &blocklisted) < 0)
3367 			goto bad;
3368 
3369 		/* version >= 3, feature bits */
3370 		ceph_decode_32_safe(&p, end, len, bad);
3371 		if (len) {
3372 			ceph_decode_64_safe(&p, end, features, bad);
3373 			p += len - sizeof(features);
3374 		}
3375 	}
3376 
3377 	if (msg_version >= 5) {
3378 		u32 flags;
3379 		/* version >= 4, struct_v, struct_cv, len, metric_spec */
3380 	        ceph_decode_skip_n(&p, end, 2 + sizeof(u32) * 2, bad);
3381 		/* version >= 5, flags   */
3382                 ceph_decode_32_safe(&p, end, flags, bad);
3383 		if (flags & CEPH_SESSION_BLOCKLISTED) {
3384 		        pr_warn("mds%d session blocklisted\n", session->s_mds);
3385 			blocklisted = true;
3386 		}
3387 	}
3388 
3389 	mutex_lock(&mdsc->mutex);
3390 	if (op == CEPH_SESSION_CLOSE) {
3391 		ceph_get_mds_session(session);
3392 		__unregister_session(mdsc, session);
3393 	}
3394 	/* FIXME: this ttl calculation is generous */
3395 	session->s_ttl = jiffies + HZ*mdsc->mdsmap->m_session_autoclose;
3396 	mutex_unlock(&mdsc->mutex);
3397 
3398 	mutex_lock(&session->s_mutex);
3399 
3400 	dout("handle_session mds%d %s %p state %s seq %llu\n",
3401 	     mds, ceph_session_op_name(op), session,
3402 	     ceph_session_state_name(session->s_state), seq);
3403 
3404 	if (session->s_state == CEPH_MDS_SESSION_HUNG) {
3405 		session->s_state = CEPH_MDS_SESSION_OPEN;
3406 		pr_info("mds%d came back\n", session->s_mds);
3407 	}
3408 
3409 	switch (op) {
3410 	case CEPH_SESSION_OPEN:
3411 		if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
3412 			pr_info("mds%d reconnect success\n", session->s_mds);
3413 		session->s_state = CEPH_MDS_SESSION_OPEN;
3414 		session->s_features = features;
3415 		renewed_caps(mdsc, session, 0);
3416 		if (test_bit(CEPHFS_FEATURE_METRIC_COLLECT, &session->s_features))
3417 			metric_schedule_delayed(&mdsc->metric);
3418 		wake = 1;
3419 		if (mdsc->stopping)
3420 			__close_session(mdsc, session);
3421 		break;
3422 
3423 	case CEPH_SESSION_RENEWCAPS:
3424 		if (session->s_renew_seq == seq)
3425 			renewed_caps(mdsc, session, 1);
3426 		break;
3427 
3428 	case CEPH_SESSION_CLOSE:
3429 		if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
3430 			pr_info("mds%d reconnect denied\n", session->s_mds);
3431 		session->s_state = CEPH_MDS_SESSION_CLOSED;
3432 		cleanup_session_requests(mdsc, session);
3433 		remove_session_caps(session);
3434 		wake = 2; /* for good measure */
3435 		wake_up_all(&mdsc->session_close_wq);
3436 		break;
3437 
3438 	case CEPH_SESSION_STALE:
3439 		pr_info("mds%d caps went stale, renewing\n",
3440 			session->s_mds);
3441 		atomic_inc(&session->s_cap_gen);
3442 		session->s_cap_ttl = jiffies - 1;
3443 		send_renew_caps(mdsc, session);
3444 		break;
3445 
3446 	case CEPH_SESSION_RECALL_STATE:
3447 		ceph_trim_caps(mdsc, session, le32_to_cpu(h->max_caps));
3448 		break;
3449 
3450 	case CEPH_SESSION_FLUSHMSG:
3451 		send_flushmsg_ack(mdsc, session, seq);
3452 		break;
3453 
3454 	case CEPH_SESSION_FORCE_RO:
3455 		dout("force_session_readonly %p\n", session);
3456 		spin_lock(&session->s_cap_lock);
3457 		session->s_readonly = true;
3458 		spin_unlock(&session->s_cap_lock);
3459 		wake_up_session_caps(session, FORCE_RO);
3460 		break;
3461 
3462 	case CEPH_SESSION_REJECT:
3463 		WARN_ON(session->s_state != CEPH_MDS_SESSION_OPENING);
3464 		pr_info("mds%d rejected session\n", session->s_mds);
3465 		session->s_state = CEPH_MDS_SESSION_REJECTED;
3466 		cleanup_session_requests(mdsc, session);
3467 		remove_session_caps(session);
3468 		if (blocklisted)
3469 			mdsc->fsc->blocklisted = true;
3470 		wake = 2; /* for good measure */
3471 		break;
3472 
3473 	default:
3474 		pr_err("mdsc_handle_session bad op %d mds%d\n", op, mds);
3475 		WARN_ON(1);
3476 	}
3477 
3478 	mutex_unlock(&session->s_mutex);
3479 	if (wake) {
3480 		mutex_lock(&mdsc->mutex);
3481 		__wake_requests(mdsc, &session->s_waiting);
3482 		if (wake == 2)
3483 			kick_requests(mdsc, mds);
3484 		mutex_unlock(&mdsc->mutex);
3485 	}
3486 	if (op == CEPH_SESSION_CLOSE)
3487 		ceph_put_mds_session(session);
3488 	return;
3489 
3490 bad:
3491 	pr_err("mdsc_handle_session corrupt message mds%d len %d\n", mds,
3492 	       (int)msg->front.iov_len);
3493 	ceph_msg_dump(msg);
3494 	return;
3495 }
3496 
3497 void ceph_mdsc_release_dir_caps(struct ceph_mds_request *req)
3498 {
3499 	int dcaps;
3500 
3501 	dcaps = xchg(&req->r_dir_caps, 0);
3502 	if (dcaps) {
3503 		dout("releasing r_dir_caps=%s\n", ceph_cap_string(dcaps));
3504 		ceph_put_cap_refs(ceph_inode(req->r_parent), dcaps);
3505 	}
3506 }
3507 
3508 void ceph_mdsc_release_dir_caps_no_check(struct ceph_mds_request *req)
3509 {
3510 	int dcaps;
3511 
3512 	dcaps = xchg(&req->r_dir_caps, 0);
3513 	if (dcaps) {
3514 		dout("releasing r_dir_caps=%s\n", ceph_cap_string(dcaps));
3515 		ceph_put_cap_refs_no_check_caps(ceph_inode(req->r_parent),
3516 						dcaps);
3517 	}
3518 }
3519 
3520 /*
3521  * called under session->mutex.
3522  */
3523 static void replay_unsafe_requests(struct ceph_mds_client *mdsc,
3524 				   struct ceph_mds_session *session)
3525 {
3526 	struct ceph_mds_request *req, *nreq;
3527 	struct rb_node *p;
3528 
3529 	dout("replay_unsafe_requests mds%d\n", session->s_mds);
3530 
3531 	mutex_lock(&mdsc->mutex);
3532 	list_for_each_entry_safe(req, nreq, &session->s_unsafe, r_unsafe_item)
3533 		__send_request(session, req, true);
3534 
3535 	/*
3536 	 * also re-send old requests when MDS enters reconnect stage. So that MDS
3537 	 * can process completed request in clientreplay stage.
3538 	 */
3539 	p = rb_first(&mdsc->request_tree);
3540 	while (p) {
3541 		req = rb_entry(p, struct ceph_mds_request, r_node);
3542 		p = rb_next(p);
3543 		if (test_bit(CEPH_MDS_R_GOT_UNSAFE, &req->r_req_flags))
3544 			continue;
3545 		if (req->r_attempts == 0)
3546 			continue; /* only old requests */
3547 		if (!req->r_session)
3548 			continue;
3549 		if (req->r_session->s_mds != session->s_mds)
3550 			continue;
3551 
3552 		ceph_mdsc_release_dir_caps_no_check(req);
3553 
3554 		__send_request(session, req, true);
3555 	}
3556 	mutex_unlock(&mdsc->mutex);
3557 }
3558 
3559 static int send_reconnect_partial(struct ceph_reconnect_state *recon_state)
3560 {
3561 	struct ceph_msg *reply;
3562 	struct ceph_pagelist *_pagelist;
3563 	struct page *page;
3564 	__le32 *addr;
3565 	int err = -ENOMEM;
3566 
3567 	if (!recon_state->allow_multi)
3568 		return -ENOSPC;
3569 
3570 	/* can't handle message that contains both caps and realm */
3571 	BUG_ON(!recon_state->nr_caps == !recon_state->nr_realms);
3572 
3573 	/* pre-allocate new pagelist */
3574 	_pagelist = ceph_pagelist_alloc(GFP_NOFS);
3575 	if (!_pagelist)
3576 		return -ENOMEM;
3577 
3578 	reply = ceph_msg_new2(CEPH_MSG_CLIENT_RECONNECT, 0, 1, GFP_NOFS, false);
3579 	if (!reply)
3580 		goto fail_msg;
3581 
3582 	/* placeholder for nr_caps */
3583 	err = ceph_pagelist_encode_32(_pagelist, 0);
3584 	if (err < 0)
3585 		goto fail;
3586 
3587 	if (recon_state->nr_caps) {
3588 		/* currently encoding caps */
3589 		err = ceph_pagelist_encode_32(recon_state->pagelist, 0);
3590 		if (err)
3591 			goto fail;
3592 	} else {
3593 		/* placeholder for nr_realms (currently encoding relams) */
3594 		err = ceph_pagelist_encode_32(_pagelist, 0);
3595 		if (err < 0)
3596 			goto fail;
3597 	}
3598 
3599 	err = ceph_pagelist_encode_8(recon_state->pagelist, 1);
3600 	if (err)
3601 		goto fail;
3602 
3603 	page = list_first_entry(&recon_state->pagelist->head, struct page, lru);
3604 	addr = kmap_atomic(page);
3605 	if (recon_state->nr_caps) {
3606 		/* currently encoding caps */
3607 		*addr = cpu_to_le32(recon_state->nr_caps);
3608 	} else {
3609 		/* currently encoding relams */
3610 		*(addr + 1) = cpu_to_le32(recon_state->nr_realms);
3611 	}
3612 	kunmap_atomic(addr);
3613 
3614 	reply->hdr.version = cpu_to_le16(5);
3615 	reply->hdr.compat_version = cpu_to_le16(4);
3616 
3617 	reply->hdr.data_len = cpu_to_le32(recon_state->pagelist->length);
3618 	ceph_msg_data_add_pagelist(reply, recon_state->pagelist);
3619 
3620 	ceph_con_send(&recon_state->session->s_con, reply);
3621 	ceph_pagelist_release(recon_state->pagelist);
3622 
3623 	recon_state->pagelist = _pagelist;
3624 	recon_state->nr_caps = 0;
3625 	recon_state->nr_realms = 0;
3626 	recon_state->msg_version = 5;
3627 	return 0;
3628 fail:
3629 	ceph_msg_put(reply);
3630 fail_msg:
3631 	ceph_pagelist_release(_pagelist);
3632 	return err;
3633 }
3634 
3635 static struct dentry* d_find_primary(struct inode *inode)
3636 {
3637 	struct dentry *alias, *dn = NULL;
3638 
3639 	if (hlist_empty(&inode->i_dentry))
3640 		return NULL;
3641 
3642 	spin_lock(&inode->i_lock);
3643 	if (hlist_empty(&inode->i_dentry))
3644 		goto out_unlock;
3645 
3646 	if (S_ISDIR(inode->i_mode)) {
3647 		alias = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias);
3648 		if (!IS_ROOT(alias))
3649 			dn = dget(alias);
3650 		goto out_unlock;
3651 	}
3652 
3653 	hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
3654 		spin_lock(&alias->d_lock);
3655 		if (!d_unhashed(alias) &&
3656 		    (ceph_dentry(alias)->flags & CEPH_DENTRY_PRIMARY_LINK)) {
3657 			dn = dget_dlock(alias);
3658 		}
3659 		spin_unlock(&alias->d_lock);
3660 		if (dn)
3661 			break;
3662 	}
3663 out_unlock:
3664 	spin_unlock(&inode->i_lock);
3665 	return dn;
3666 }
3667 
3668 /*
3669  * Encode information about a cap for a reconnect with the MDS.
3670  */
3671 static int reconnect_caps_cb(struct inode *inode, struct ceph_cap *cap,
3672 			  void *arg)
3673 {
3674 	union {
3675 		struct ceph_mds_cap_reconnect v2;
3676 		struct ceph_mds_cap_reconnect_v1 v1;
3677 	} rec;
3678 	struct ceph_inode_info *ci = cap->ci;
3679 	struct ceph_reconnect_state *recon_state = arg;
3680 	struct ceph_pagelist *pagelist = recon_state->pagelist;
3681 	struct dentry *dentry;
3682 	char *path;
3683 	int pathlen = 0, err;
3684 	u64 pathbase;
3685 	u64 snap_follows;
3686 
3687 	dout(" adding %p ino %llx.%llx cap %p %lld %s\n",
3688 	     inode, ceph_vinop(inode), cap, cap->cap_id,
3689 	     ceph_cap_string(cap->issued));
3690 
3691 	dentry = d_find_primary(inode);
3692 	if (dentry) {
3693 		/* set pathbase to parent dir when msg_version >= 2 */
3694 		path = ceph_mdsc_build_path(dentry, &pathlen, &pathbase,
3695 					    recon_state->msg_version >= 2);
3696 		dput(dentry);
3697 		if (IS_ERR(path)) {
3698 			err = PTR_ERR(path);
3699 			goto out_err;
3700 		}
3701 	} else {
3702 		path = NULL;
3703 		pathbase = 0;
3704 	}
3705 
3706 	spin_lock(&ci->i_ceph_lock);
3707 	cap->seq = 0;        /* reset cap seq */
3708 	cap->issue_seq = 0;  /* and issue_seq */
3709 	cap->mseq = 0;       /* and migrate_seq */
3710 	cap->cap_gen = atomic_read(&cap->session->s_cap_gen);
3711 
3712 	/* These are lost when the session goes away */
3713 	if (S_ISDIR(inode->i_mode)) {
3714 		if (cap->issued & CEPH_CAP_DIR_CREATE) {
3715 			ceph_put_string(rcu_dereference_raw(ci->i_cached_layout.pool_ns));
3716 			memset(&ci->i_cached_layout, 0, sizeof(ci->i_cached_layout));
3717 		}
3718 		cap->issued &= ~CEPH_CAP_ANY_DIR_OPS;
3719 	}
3720 
3721 	if (recon_state->msg_version >= 2) {
3722 		rec.v2.cap_id = cpu_to_le64(cap->cap_id);
3723 		rec.v2.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
3724 		rec.v2.issued = cpu_to_le32(cap->issued);
3725 		rec.v2.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
3726 		rec.v2.pathbase = cpu_to_le64(pathbase);
3727 		rec.v2.flock_len = (__force __le32)
3728 			((ci->i_ceph_flags & CEPH_I_ERROR_FILELOCK) ? 0 : 1);
3729 	} else {
3730 		rec.v1.cap_id = cpu_to_le64(cap->cap_id);
3731 		rec.v1.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
3732 		rec.v1.issued = cpu_to_le32(cap->issued);
3733 		rec.v1.size = cpu_to_le64(i_size_read(inode));
3734 		ceph_encode_timespec64(&rec.v1.mtime, &inode->i_mtime);
3735 		ceph_encode_timespec64(&rec.v1.atime, &inode->i_atime);
3736 		rec.v1.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
3737 		rec.v1.pathbase = cpu_to_le64(pathbase);
3738 	}
3739 
3740 	if (list_empty(&ci->i_cap_snaps)) {
3741 		snap_follows = ci->i_head_snapc ? ci->i_head_snapc->seq : 0;
3742 	} else {
3743 		struct ceph_cap_snap *capsnap =
3744 			list_first_entry(&ci->i_cap_snaps,
3745 					 struct ceph_cap_snap, ci_item);
3746 		snap_follows = capsnap->follows;
3747 	}
3748 	spin_unlock(&ci->i_ceph_lock);
3749 
3750 	if (recon_state->msg_version >= 2) {
3751 		int num_fcntl_locks, num_flock_locks;
3752 		struct ceph_filelock *flocks = NULL;
3753 		size_t struct_len, total_len = sizeof(u64);
3754 		u8 struct_v = 0;
3755 
3756 encode_again:
3757 		if (rec.v2.flock_len) {
3758 			ceph_count_locks(inode, &num_fcntl_locks, &num_flock_locks);
3759 		} else {
3760 			num_fcntl_locks = 0;
3761 			num_flock_locks = 0;
3762 		}
3763 		if (num_fcntl_locks + num_flock_locks > 0) {
3764 			flocks = kmalloc_array(num_fcntl_locks + num_flock_locks,
3765 					       sizeof(struct ceph_filelock),
3766 					       GFP_NOFS);
3767 			if (!flocks) {
3768 				err = -ENOMEM;
3769 				goto out_err;
3770 			}
3771 			err = ceph_encode_locks_to_buffer(inode, flocks,
3772 							  num_fcntl_locks,
3773 							  num_flock_locks);
3774 			if (err) {
3775 				kfree(flocks);
3776 				flocks = NULL;
3777 				if (err == -ENOSPC)
3778 					goto encode_again;
3779 				goto out_err;
3780 			}
3781 		} else {
3782 			kfree(flocks);
3783 			flocks = NULL;
3784 		}
3785 
3786 		if (recon_state->msg_version >= 3) {
3787 			/* version, compat_version and struct_len */
3788 			total_len += 2 * sizeof(u8) + sizeof(u32);
3789 			struct_v = 2;
3790 		}
3791 		/*
3792 		 * number of encoded locks is stable, so copy to pagelist
3793 		 */
3794 		struct_len = 2 * sizeof(u32) +
3795 			    (num_fcntl_locks + num_flock_locks) *
3796 			    sizeof(struct ceph_filelock);
3797 		rec.v2.flock_len = cpu_to_le32(struct_len);
3798 
3799 		struct_len += sizeof(u32) + pathlen + sizeof(rec.v2);
3800 
3801 		if (struct_v >= 2)
3802 			struct_len += sizeof(u64); /* snap_follows */
3803 
3804 		total_len += struct_len;
3805 
3806 		if (pagelist->length + total_len > RECONNECT_MAX_SIZE) {
3807 			err = send_reconnect_partial(recon_state);
3808 			if (err)
3809 				goto out_freeflocks;
3810 			pagelist = recon_state->pagelist;
3811 		}
3812 
3813 		err = ceph_pagelist_reserve(pagelist, total_len);
3814 		if (err)
3815 			goto out_freeflocks;
3816 
3817 		ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
3818 		if (recon_state->msg_version >= 3) {
3819 			ceph_pagelist_encode_8(pagelist, struct_v);
3820 			ceph_pagelist_encode_8(pagelist, 1);
3821 			ceph_pagelist_encode_32(pagelist, struct_len);
3822 		}
3823 		ceph_pagelist_encode_string(pagelist, path, pathlen);
3824 		ceph_pagelist_append(pagelist, &rec, sizeof(rec.v2));
3825 		ceph_locks_to_pagelist(flocks, pagelist,
3826 				       num_fcntl_locks, num_flock_locks);
3827 		if (struct_v >= 2)
3828 			ceph_pagelist_encode_64(pagelist, snap_follows);
3829 out_freeflocks:
3830 		kfree(flocks);
3831 	} else {
3832 		err = ceph_pagelist_reserve(pagelist,
3833 					    sizeof(u64) + sizeof(u32) +
3834 					    pathlen + sizeof(rec.v1));
3835 		if (err)
3836 			goto out_err;
3837 
3838 		ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
3839 		ceph_pagelist_encode_string(pagelist, path, pathlen);
3840 		ceph_pagelist_append(pagelist, &rec, sizeof(rec.v1));
3841 	}
3842 
3843 out_err:
3844 	ceph_mdsc_free_path(path, pathlen);
3845 	if (!err)
3846 		recon_state->nr_caps++;
3847 	return err;
3848 }
3849 
3850 static int encode_snap_realms(struct ceph_mds_client *mdsc,
3851 			      struct ceph_reconnect_state *recon_state)
3852 {
3853 	struct rb_node *p;
3854 	struct ceph_pagelist *pagelist = recon_state->pagelist;
3855 	int err = 0;
3856 
3857 	if (recon_state->msg_version >= 4) {
3858 		err = ceph_pagelist_encode_32(pagelist, mdsc->num_snap_realms);
3859 		if (err < 0)
3860 			goto fail;
3861 	}
3862 
3863 	/*
3864 	 * snaprealms.  we provide mds with the ino, seq (version), and
3865 	 * parent for all of our realms.  If the mds has any newer info,
3866 	 * it will tell us.
3867 	 */
3868 	for (p = rb_first(&mdsc->snap_realms); p; p = rb_next(p)) {
3869 		struct ceph_snap_realm *realm =
3870 		       rb_entry(p, struct ceph_snap_realm, node);
3871 		struct ceph_mds_snaprealm_reconnect sr_rec;
3872 
3873 		if (recon_state->msg_version >= 4) {
3874 			size_t need = sizeof(u8) * 2 + sizeof(u32) +
3875 				      sizeof(sr_rec);
3876 
3877 			if (pagelist->length + need > RECONNECT_MAX_SIZE) {
3878 				err = send_reconnect_partial(recon_state);
3879 				if (err)
3880 					goto fail;
3881 				pagelist = recon_state->pagelist;
3882 			}
3883 
3884 			err = ceph_pagelist_reserve(pagelist, need);
3885 			if (err)
3886 				goto fail;
3887 
3888 			ceph_pagelist_encode_8(pagelist, 1);
3889 			ceph_pagelist_encode_8(pagelist, 1);
3890 			ceph_pagelist_encode_32(pagelist, sizeof(sr_rec));
3891 		}
3892 
3893 		dout(" adding snap realm %llx seq %lld parent %llx\n",
3894 		     realm->ino, realm->seq, realm->parent_ino);
3895 		sr_rec.ino = cpu_to_le64(realm->ino);
3896 		sr_rec.seq = cpu_to_le64(realm->seq);
3897 		sr_rec.parent = cpu_to_le64(realm->parent_ino);
3898 
3899 		err = ceph_pagelist_append(pagelist, &sr_rec, sizeof(sr_rec));
3900 		if (err)
3901 			goto fail;
3902 
3903 		recon_state->nr_realms++;
3904 	}
3905 fail:
3906 	return err;
3907 }
3908 
3909 
3910 /*
3911  * If an MDS fails and recovers, clients need to reconnect in order to
3912  * reestablish shared state.  This includes all caps issued through
3913  * this session _and_ the snap_realm hierarchy.  Because it's not
3914  * clear which snap realms the mds cares about, we send everything we
3915  * know about.. that ensures we'll then get any new info the
3916  * recovering MDS might have.
3917  *
3918  * This is a relatively heavyweight operation, but it's rare.
3919  */
3920 static void send_mds_reconnect(struct ceph_mds_client *mdsc,
3921 			       struct ceph_mds_session *session)
3922 {
3923 	struct ceph_msg *reply;
3924 	int mds = session->s_mds;
3925 	int err = -ENOMEM;
3926 	struct ceph_reconnect_state recon_state = {
3927 		.session = session,
3928 	};
3929 	LIST_HEAD(dispose);
3930 
3931 	pr_info("mds%d reconnect start\n", mds);
3932 
3933 	recon_state.pagelist = ceph_pagelist_alloc(GFP_NOFS);
3934 	if (!recon_state.pagelist)
3935 		goto fail_nopagelist;
3936 
3937 	reply = ceph_msg_new2(CEPH_MSG_CLIENT_RECONNECT, 0, 1, GFP_NOFS, false);
3938 	if (!reply)
3939 		goto fail_nomsg;
3940 
3941 	xa_destroy(&session->s_delegated_inos);
3942 
3943 	mutex_lock(&session->s_mutex);
3944 	session->s_state = CEPH_MDS_SESSION_RECONNECTING;
3945 	session->s_seq = 0;
3946 
3947 	dout("session %p state %s\n", session,
3948 	     ceph_session_state_name(session->s_state));
3949 
3950 	atomic_inc(&session->s_cap_gen);
3951 
3952 	spin_lock(&session->s_cap_lock);
3953 	/* don't know if session is readonly */
3954 	session->s_readonly = 0;
3955 	/*
3956 	 * notify __ceph_remove_cap() that we are composing cap reconnect.
3957 	 * If a cap get released before being added to the cap reconnect,
3958 	 * __ceph_remove_cap() should skip queuing cap release.
3959 	 */
3960 	session->s_cap_reconnect = 1;
3961 	/* drop old cap expires; we're about to reestablish that state */
3962 	detach_cap_releases(session, &dispose);
3963 	spin_unlock(&session->s_cap_lock);
3964 	dispose_cap_releases(mdsc, &dispose);
3965 
3966 	/* trim unused caps to reduce MDS's cache rejoin time */
3967 	if (mdsc->fsc->sb->s_root)
3968 		shrink_dcache_parent(mdsc->fsc->sb->s_root);
3969 
3970 	ceph_con_close(&session->s_con);
3971 	ceph_con_open(&session->s_con,
3972 		      CEPH_ENTITY_TYPE_MDS, mds,
3973 		      ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
3974 
3975 	/* replay unsafe requests */
3976 	replay_unsafe_requests(mdsc, session);
3977 
3978 	ceph_early_kick_flushing_caps(mdsc, session);
3979 
3980 	down_read(&mdsc->snap_rwsem);
3981 
3982 	/* placeholder for nr_caps */
3983 	err = ceph_pagelist_encode_32(recon_state.pagelist, 0);
3984 	if (err)
3985 		goto fail;
3986 
3987 	if (test_bit(CEPHFS_FEATURE_MULTI_RECONNECT, &session->s_features)) {
3988 		recon_state.msg_version = 3;
3989 		recon_state.allow_multi = true;
3990 	} else if (session->s_con.peer_features & CEPH_FEATURE_MDSENC) {
3991 		recon_state.msg_version = 3;
3992 	} else {
3993 		recon_state.msg_version = 2;
3994 	}
3995 	/* trsaverse this session's caps */
3996 	err = ceph_iterate_session_caps(session, reconnect_caps_cb, &recon_state);
3997 
3998 	spin_lock(&session->s_cap_lock);
3999 	session->s_cap_reconnect = 0;
4000 	spin_unlock(&session->s_cap_lock);
4001 
4002 	if (err < 0)
4003 		goto fail;
4004 
4005 	/* check if all realms can be encoded into current message */
4006 	if (mdsc->num_snap_realms) {
4007 		size_t total_len =
4008 			recon_state.pagelist->length +
4009 			mdsc->num_snap_realms *
4010 			sizeof(struct ceph_mds_snaprealm_reconnect);
4011 		if (recon_state.msg_version >= 4) {
4012 			/* number of realms */
4013 			total_len += sizeof(u32);
4014 			/* version, compat_version and struct_len */
4015 			total_len += mdsc->num_snap_realms *
4016 				     (2 * sizeof(u8) + sizeof(u32));
4017 		}
4018 		if (total_len > RECONNECT_MAX_SIZE) {
4019 			if (!recon_state.allow_multi) {
4020 				err = -ENOSPC;
4021 				goto fail;
4022 			}
4023 			if (recon_state.nr_caps) {
4024 				err = send_reconnect_partial(&recon_state);
4025 				if (err)
4026 					goto fail;
4027 			}
4028 			recon_state.msg_version = 5;
4029 		}
4030 	}
4031 
4032 	err = encode_snap_realms(mdsc, &recon_state);
4033 	if (err < 0)
4034 		goto fail;
4035 
4036 	if (recon_state.msg_version >= 5) {
4037 		err = ceph_pagelist_encode_8(recon_state.pagelist, 0);
4038 		if (err < 0)
4039 			goto fail;
4040 	}
4041 
4042 	if (recon_state.nr_caps || recon_state.nr_realms) {
4043 		struct page *page =
4044 			list_first_entry(&recon_state.pagelist->head,
4045 					struct page, lru);
4046 		__le32 *addr = kmap_atomic(page);
4047 		if (recon_state.nr_caps) {
4048 			WARN_ON(recon_state.nr_realms != mdsc->num_snap_realms);
4049 			*addr = cpu_to_le32(recon_state.nr_caps);
4050 		} else if (recon_state.msg_version >= 4) {
4051 			*(addr + 1) = cpu_to_le32(recon_state.nr_realms);
4052 		}
4053 		kunmap_atomic(addr);
4054 	}
4055 
4056 	reply->hdr.version = cpu_to_le16(recon_state.msg_version);
4057 	if (recon_state.msg_version >= 4)
4058 		reply->hdr.compat_version = cpu_to_le16(4);
4059 
4060 	reply->hdr.data_len = cpu_to_le32(recon_state.pagelist->length);
4061 	ceph_msg_data_add_pagelist(reply, recon_state.pagelist);
4062 
4063 	ceph_con_send(&session->s_con, reply);
4064 
4065 	mutex_unlock(&session->s_mutex);
4066 
4067 	mutex_lock(&mdsc->mutex);
4068 	__wake_requests(mdsc, &session->s_waiting);
4069 	mutex_unlock(&mdsc->mutex);
4070 
4071 	up_read(&mdsc->snap_rwsem);
4072 	ceph_pagelist_release(recon_state.pagelist);
4073 	return;
4074 
4075 fail:
4076 	ceph_msg_put(reply);
4077 	up_read(&mdsc->snap_rwsem);
4078 	mutex_unlock(&session->s_mutex);
4079 fail_nomsg:
4080 	ceph_pagelist_release(recon_state.pagelist);
4081 fail_nopagelist:
4082 	pr_err("error %d preparing reconnect for mds%d\n", err, mds);
4083 	return;
4084 }
4085 
4086 
4087 /*
4088  * compare old and new mdsmaps, kicking requests
4089  * and closing out old connections as necessary
4090  *
4091  * called under mdsc->mutex.
4092  */
4093 static void check_new_map(struct ceph_mds_client *mdsc,
4094 			  struct ceph_mdsmap *newmap,
4095 			  struct ceph_mdsmap *oldmap)
4096 {
4097 	int i, j, err;
4098 	int oldstate, newstate;
4099 	struct ceph_mds_session *s;
4100 	unsigned long targets[DIV_ROUND_UP(CEPH_MAX_MDS, sizeof(unsigned long))] = {0};
4101 
4102 	dout("check_new_map new %u old %u\n",
4103 	     newmap->m_epoch, oldmap->m_epoch);
4104 
4105 	if (newmap->m_info) {
4106 		for (i = 0; i < newmap->possible_max_rank; i++) {
4107 			for (j = 0; j < newmap->m_info[i].num_export_targets; j++)
4108 				set_bit(newmap->m_info[i].export_targets[j], targets);
4109 		}
4110 	}
4111 
4112 	for (i = 0; i < oldmap->possible_max_rank && i < mdsc->max_sessions; i++) {
4113 		if (!mdsc->sessions[i])
4114 			continue;
4115 		s = mdsc->sessions[i];
4116 		oldstate = ceph_mdsmap_get_state(oldmap, i);
4117 		newstate = ceph_mdsmap_get_state(newmap, i);
4118 
4119 		dout("check_new_map mds%d state %s%s -> %s%s (session %s)\n",
4120 		     i, ceph_mds_state_name(oldstate),
4121 		     ceph_mdsmap_is_laggy(oldmap, i) ? " (laggy)" : "",
4122 		     ceph_mds_state_name(newstate),
4123 		     ceph_mdsmap_is_laggy(newmap, i) ? " (laggy)" : "",
4124 		     ceph_session_state_name(s->s_state));
4125 
4126 		if (i >= newmap->possible_max_rank) {
4127 			/* force close session for stopped mds */
4128 			ceph_get_mds_session(s);
4129 			__unregister_session(mdsc, s);
4130 			__wake_requests(mdsc, &s->s_waiting);
4131 			mutex_unlock(&mdsc->mutex);
4132 
4133 			mutex_lock(&s->s_mutex);
4134 			cleanup_session_requests(mdsc, s);
4135 			remove_session_caps(s);
4136 			mutex_unlock(&s->s_mutex);
4137 
4138 			ceph_put_mds_session(s);
4139 
4140 			mutex_lock(&mdsc->mutex);
4141 			kick_requests(mdsc, i);
4142 			continue;
4143 		}
4144 
4145 		if (memcmp(ceph_mdsmap_get_addr(oldmap, i),
4146 			   ceph_mdsmap_get_addr(newmap, i),
4147 			   sizeof(struct ceph_entity_addr))) {
4148 			/* just close it */
4149 			mutex_unlock(&mdsc->mutex);
4150 			mutex_lock(&s->s_mutex);
4151 			mutex_lock(&mdsc->mutex);
4152 			ceph_con_close(&s->s_con);
4153 			mutex_unlock(&s->s_mutex);
4154 			s->s_state = CEPH_MDS_SESSION_RESTARTING;
4155 		} else if (oldstate == newstate) {
4156 			continue;  /* nothing new with this mds */
4157 		}
4158 
4159 		/*
4160 		 * send reconnect?
4161 		 */
4162 		if (s->s_state == CEPH_MDS_SESSION_RESTARTING &&
4163 		    newstate >= CEPH_MDS_STATE_RECONNECT) {
4164 			mutex_unlock(&mdsc->mutex);
4165 			clear_bit(i, targets);
4166 			send_mds_reconnect(mdsc, s);
4167 			mutex_lock(&mdsc->mutex);
4168 		}
4169 
4170 		/*
4171 		 * kick request on any mds that has gone active.
4172 		 */
4173 		if (oldstate < CEPH_MDS_STATE_ACTIVE &&
4174 		    newstate >= CEPH_MDS_STATE_ACTIVE) {
4175 			if (oldstate != CEPH_MDS_STATE_CREATING &&
4176 			    oldstate != CEPH_MDS_STATE_STARTING)
4177 				pr_info("mds%d recovery completed\n", s->s_mds);
4178 			kick_requests(mdsc, i);
4179 			mutex_unlock(&mdsc->mutex);
4180 			mutex_lock(&s->s_mutex);
4181 			mutex_lock(&mdsc->mutex);
4182 			ceph_kick_flushing_caps(mdsc, s);
4183 			mutex_unlock(&s->s_mutex);
4184 			wake_up_session_caps(s, RECONNECT);
4185 		}
4186 	}
4187 
4188 	/*
4189 	 * Only open and reconnect sessions that don't exist yet.
4190 	 */
4191 	for (i = 0; i < newmap->possible_max_rank; i++) {
4192 		/*
4193 		 * In case the import MDS is crashed just after
4194 		 * the EImportStart journal is flushed, so when
4195 		 * a standby MDS takes over it and is replaying
4196 		 * the EImportStart journal the new MDS daemon
4197 		 * will wait the client to reconnect it, but the
4198 		 * client may never register/open the session yet.
4199 		 *
4200 		 * Will try to reconnect that MDS daemon if the
4201 		 * rank number is in the export targets array and
4202 		 * is the up:reconnect state.
4203 		 */
4204 		newstate = ceph_mdsmap_get_state(newmap, i);
4205 		if (!test_bit(i, targets) || newstate != CEPH_MDS_STATE_RECONNECT)
4206 			continue;
4207 
4208 		/*
4209 		 * The session maybe registered and opened by some
4210 		 * requests which were choosing random MDSes during
4211 		 * the mdsc->mutex's unlock/lock gap below in rare
4212 		 * case. But the related MDS daemon will just queue
4213 		 * that requests and be still waiting for the client's
4214 		 * reconnection request in up:reconnect state.
4215 		 */
4216 		s = __ceph_lookup_mds_session(mdsc, i);
4217 		if (likely(!s)) {
4218 			s = __open_export_target_session(mdsc, i);
4219 			if (IS_ERR(s)) {
4220 				err = PTR_ERR(s);
4221 				pr_err("failed to open export target session, err %d\n",
4222 				       err);
4223 				continue;
4224 			}
4225 		}
4226 		dout("send reconnect to export target mds.%d\n", i);
4227 		mutex_unlock(&mdsc->mutex);
4228 		send_mds_reconnect(mdsc, s);
4229 		ceph_put_mds_session(s);
4230 		mutex_lock(&mdsc->mutex);
4231 	}
4232 
4233 	for (i = 0; i < newmap->possible_max_rank && i < mdsc->max_sessions; i++) {
4234 		s = mdsc->sessions[i];
4235 		if (!s)
4236 			continue;
4237 		if (!ceph_mdsmap_is_laggy(newmap, i))
4238 			continue;
4239 		if (s->s_state == CEPH_MDS_SESSION_OPEN ||
4240 		    s->s_state == CEPH_MDS_SESSION_HUNG ||
4241 		    s->s_state == CEPH_MDS_SESSION_CLOSING) {
4242 			dout(" connecting to export targets of laggy mds%d\n",
4243 			     i);
4244 			__open_export_target_sessions(mdsc, s);
4245 		}
4246 	}
4247 }
4248 
4249 
4250 
4251 /*
4252  * leases
4253  */
4254 
4255 /*
4256  * caller must hold session s_mutex, dentry->d_lock
4257  */
4258 void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry)
4259 {
4260 	struct ceph_dentry_info *di = ceph_dentry(dentry);
4261 
4262 	ceph_put_mds_session(di->lease_session);
4263 	di->lease_session = NULL;
4264 }
4265 
4266 static void handle_lease(struct ceph_mds_client *mdsc,
4267 			 struct ceph_mds_session *session,
4268 			 struct ceph_msg *msg)
4269 {
4270 	struct super_block *sb = mdsc->fsc->sb;
4271 	struct inode *inode;
4272 	struct dentry *parent, *dentry;
4273 	struct ceph_dentry_info *di;
4274 	int mds = session->s_mds;
4275 	struct ceph_mds_lease *h = msg->front.iov_base;
4276 	u32 seq;
4277 	struct ceph_vino vino;
4278 	struct qstr dname;
4279 	int release = 0;
4280 
4281 	dout("handle_lease from mds%d\n", mds);
4282 
4283 	/* decode */
4284 	if (msg->front.iov_len < sizeof(*h) + sizeof(u32))
4285 		goto bad;
4286 	vino.ino = le64_to_cpu(h->ino);
4287 	vino.snap = CEPH_NOSNAP;
4288 	seq = le32_to_cpu(h->seq);
4289 	dname.len = get_unaligned_le32(h + 1);
4290 	if (msg->front.iov_len < sizeof(*h) + sizeof(u32) + dname.len)
4291 		goto bad;
4292 	dname.name = (void *)(h + 1) + sizeof(u32);
4293 
4294 	/* lookup inode */
4295 	inode = ceph_find_inode(sb, vino);
4296 	dout("handle_lease %s, ino %llx %p %.*s\n",
4297 	     ceph_lease_op_name(h->action), vino.ino, inode,
4298 	     dname.len, dname.name);
4299 
4300 	mutex_lock(&session->s_mutex);
4301 	inc_session_sequence(session);
4302 
4303 	if (!inode) {
4304 		dout("handle_lease no inode %llx\n", vino.ino);
4305 		goto release;
4306 	}
4307 
4308 	/* dentry */
4309 	parent = d_find_alias(inode);
4310 	if (!parent) {
4311 		dout("no parent dentry on inode %p\n", inode);
4312 		WARN_ON(1);
4313 		goto release;  /* hrm... */
4314 	}
4315 	dname.hash = full_name_hash(parent, dname.name, dname.len);
4316 	dentry = d_lookup(parent, &dname);
4317 	dput(parent);
4318 	if (!dentry)
4319 		goto release;
4320 
4321 	spin_lock(&dentry->d_lock);
4322 	di = ceph_dentry(dentry);
4323 	switch (h->action) {
4324 	case CEPH_MDS_LEASE_REVOKE:
4325 		if (di->lease_session == session) {
4326 			if (ceph_seq_cmp(di->lease_seq, seq) > 0)
4327 				h->seq = cpu_to_le32(di->lease_seq);
4328 			__ceph_mdsc_drop_dentry_lease(dentry);
4329 		}
4330 		release = 1;
4331 		break;
4332 
4333 	case CEPH_MDS_LEASE_RENEW:
4334 		if (di->lease_session == session &&
4335 		    di->lease_gen == atomic_read(&session->s_cap_gen) &&
4336 		    di->lease_renew_from &&
4337 		    di->lease_renew_after == 0) {
4338 			unsigned long duration =
4339 				msecs_to_jiffies(le32_to_cpu(h->duration_ms));
4340 
4341 			di->lease_seq = seq;
4342 			di->time = di->lease_renew_from + duration;
4343 			di->lease_renew_after = di->lease_renew_from +
4344 				(duration >> 1);
4345 			di->lease_renew_from = 0;
4346 		}
4347 		break;
4348 	}
4349 	spin_unlock(&dentry->d_lock);
4350 	dput(dentry);
4351 
4352 	if (!release)
4353 		goto out;
4354 
4355 release:
4356 	/* let's just reuse the same message */
4357 	h->action = CEPH_MDS_LEASE_REVOKE_ACK;
4358 	ceph_msg_get(msg);
4359 	ceph_con_send(&session->s_con, msg);
4360 
4361 out:
4362 	mutex_unlock(&session->s_mutex);
4363 	iput(inode);
4364 	return;
4365 
4366 bad:
4367 	pr_err("corrupt lease message\n");
4368 	ceph_msg_dump(msg);
4369 }
4370 
4371 void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
4372 			      struct dentry *dentry, char action,
4373 			      u32 seq)
4374 {
4375 	struct ceph_msg *msg;
4376 	struct ceph_mds_lease *lease;
4377 	struct inode *dir;
4378 	int len = sizeof(*lease) + sizeof(u32) + NAME_MAX;
4379 
4380 	dout("lease_send_msg identry %p %s to mds%d\n",
4381 	     dentry, ceph_lease_op_name(action), session->s_mds);
4382 
4383 	msg = ceph_msg_new(CEPH_MSG_CLIENT_LEASE, len, GFP_NOFS, false);
4384 	if (!msg)
4385 		return;
4386 	lease = msg->front.iov_base;
4387 	lease->action = action;
4388 	lease->seq = cpu_to_le32(seq);
4389 
4390 	spin_lock(&dentry->d_lock);
4391 	dir = d_inode(dentry->d_parent);
4392 	lease->ino = cpu_to_le64(ceph_ino(dir));
4393 	lease->first = lease->last = cpu_to_le64(ceph_snap(dir));
4394 
4395 	put_unaligned_le32(dentry->d_name.len, lease + 1);
4396 	memcpy((void *)(lease + 1) + 4,
4397 	       dentry->d_name.name, dentry->d_name.len);
4398 	spin_unlock(&dentry->d_lock);
4399 	/*
4400 	 * if this is a preemptive lease RELEASE, no need to
4401 	 * flush request stream, since the actual request will
4402 	 * soon follow.
4403 	 */
4404 	msg->more_to_follow = (action == CEPH_MDS_LEASE_RELEASE);
4405 
4406 	ceph_con_send(&session->s_con, msg);
4407 }
4408 
4409 /*
4410  * lock unlock the session, to wait ongoing session activities
4411  */
4412 static void lock_unlock_session(struct ceph_mds_session *s)
4413 {
4414 	mutex_lock(&s->s_mutex);
4415 	mutex_unlock(&s->s_mutex);
4416 }
4417 
4418 static void maybe_recover_session(struct ceph_mds_client *mdsc)
4419 {
4420 	struct ceph_fs_client *fsc = mdsc->fsc;
4421 
4422 	if (!ceph_test_mount_opt(fsc, CLEANRECOVER))
4423 		return;
4424 
4425 	if (READ_ONCE(fsc->mount_state) != CEPH_MOUNT_MOUNTED)
4426 		return;
4427 
4428 	if (!READ_ONCE(fsc->blocklisted))
4429 		return;
4430 
4431 	pr_info("auto reconnect after blocklisted\n");
4432 	ceph_force_reconnect(fsc->sb);
4433 }
4434 
4435 bool check_session_state(struct ceph_mds_session *s)
4436 {
4437 	struct ceph_fs_client *fsc = s->s_mdsc->fsc;
4438 
4439 	switch (s->s_state) {
4440 	case CEPH_MDS_SESSION_OPEN:
4441 		if (s->s_ttl && time_after(jiffies, s->s_ttl)) {
4442 			s->s_state = CEPH_MDS_SESSION_HUNG;
4443 			pr_info("mds%d hung\n", s->s_mds);
4444 		}
4445 		break;
4446 	case CEPH_MDS_SESSION_CLOSING:
4447 		/* Should never reach this when not force unmounting */
4448 		WARN_ON_ONCE(s->s_ttl &&
4449 			     READ_ONCE(fsc->mount_state) != CEPH_MOUNT_SHUTDOWN);
4450 		fallthrough;
4451 	case CEPH_MDS_SESSION_NEW:
4452 	case CEPH_MDS_SESSION_RESTARTING:
4453 	case CEPH_MDS_SESSION_CLOSED:
4454 	case CEPH_MDS_SESSION_REJECTED:
4455 		return false;
4456 	}
4457 
4458 	return true;
4459 }
4460 
4461 /*
4462  * If the sequence is incremented while we're waiting on a REQUEST_CLOSE reply,
4463  * then we need to retransmit that request.
4464  */
4465 void inc_session_sequence(struct ceph_mds_session *s)
4466 {
4467 	lockdep_assert_held(&s->s_mutex);
4468 
4469 	s->s_seq++;
4470 
4471 	if (s->s_state == CEPH_MDS_SESSION_CLOSING) {
4472 		int ret;
4473 
4474 		dout("resending session close request for mds%d\n", s->s_mds);
4475 		ret = request_close_session(s);
4476 		if (ret < 0)
4477 			pr_err("unable to close session to mds%d: %d\n",
4478 			       s->s_mds, ret);
4479 	}
4480 }
4481 
4482 /*
4483  * delayed work -- periodically trim expired leases, renew caps with mds.  If
4484  * the @delay parameter is set to 0 or if it's more than 5 secs, the default
4485  * workqueue delay value of 5 secs will be used.
4486  */
4487 static void schedule_delayed(struct ceph_mds_client *mdsc, unsigned long delay)
4488 {
4489 	unsigned long max_delay = HZ * 5;
4490 
4491 	/* 5 secs default delay */
4492 	if (!delay || (delay > max_delay))
4493 		delay = max_delay;
4494 	schedule_delayed_work(&mdsc->delayed_work,
4495 			      round_jiffies_relative(delay));
4496 }
4497 
4498 static void delayed_work(struct work_struct *work)
4499 {
4500 	struct ceph_mds_client *mdsc =
4501 		container_of(work, struct ceph_mds_client, delayed_work.work);
4502 	unsigned long delay;
4503 	int renew_interval;
4504 	int renew_caps;
4505 	int i;
4506 
4507 	dout("mdsc delayed_work\n");
4508 
4509 	if (mdsc->stopping)
4510 		return;
4511 
4512 	mutex_lock(&mdsc->mutex);
4513 	renew_interval = mdsc->mdsmap->m_session_timeout >> 2;
4514 	renew_caps = time_after_eq(jiffies, HZ*renew_interval +
4515 				   mdsc->last_renew_caps);
4516 	if (renew_caps)
4517 		mdsc->last_renew_caps = jiffies;
4518 
4519 	for (i = 0; i < mdsc->max_sessions; i++) {
4520 		struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
4521 		if (!s)
4522 			continue;
4523 
4524 		if (!check_session_state(s)) {
4525 			ceph_put_mds_session(s);
4526 			continue;
4527 		}
4528 		mutex_unlock(&mdsc->mutex);
4529 
4530 		mutex_lock(&s->s_mutex);
4531 		if (renew_caps)
4532 			send_renew_caps(mdsc, s);
4533 		else
4534 			ceph_con_keepalive(&s->s_con);
4535 		if (s->s_state == CEPH_MDS_SESSION_OPEN ||
4536 		    s->s_state == CEPH_MDS_SESSION_HUNG)
4537 			ceph_send_cap_releases(mdsc, s);
4538 		mutex_unlock(&s->s_mutex);
4539 		ceph_put_mds_session(s);
4540 
4541 		mutex_lock(&mdsc->mutex);
4542 	}
4543 	mutex_unlock(&mdsc->mutex);
4544 
4545 	delay = ceph_check_delayed_caps(mdsc);
4546 
4547 	ceph_queue_cap_reclaim_work(mdsc);
4548 
4549 	ceph_trim_snapid_map(mdsc);
4550 
4551 	maybe_recover_session(mdsc);
4552 
4553 	schedule_delayed(mdsc, delay);
4554 }
4555 
4556 int ceph_mdsc_init(struct ceph_fs_client *fsc)
4557 
4558 {
4559 	struct ceph_mds_client *mdsc;
4560 	int err;
4561 
4562 	mdsc = kzalloc(sizeof(struct ceph_mds_client), GFP_NOFS);
4563 	if (!mdsc)
4564 		return -ENOMEM;
4565 	mdsc->fsc = fsc;
4566 	mutex_init(&mdsc->mutex);
4567 	mdsc->mdsmap = kzalloc(sizeof(*mdsc->mdsmap), GFP_NOFS);
4568 	if (!mdsc->mdsmap) {
4569 		err = -ENOMEM;
4570 		goto err_mdsc;
4571 	}
4572 
4573 	init_completion(&mdsc->safe_umount_waiters);
4574 	init_waitqueue_head(&mdsc->session_close_wq);
4575 	INIT_LIST_HEAD(&mdsc->waiting_for_map);
4576 	mdsc->quotarealms_inodes = RB_ROOT;
4577 	mutex_init(&mdsc->quotarealms_inodes_mutex);
4578 	init_rwsem(&mdsc->snap_rwsem);
4579 	mdsc->snap_realms = RB_ROOT;
4580 	INIT_LIST_HEAD(&mdsc->snap_empty);
4581 	spin_lock_init(&mdsc->snap_empty_lock);
4582 	mdsc->request_tree = RB_ROOT;
4583 	INIT_DELAYED_WORK(&mdsc->delayed_work, delayed_work);
4584 	mdsc->last_renew_caps = jiffies;
4585 	INIT_LIST_HEAD(&mdsc->cap_delay_list);
4586 	INIT_LIST_HEAD(&mdsc->cap_wait_list);
4587 	spin_lock_init(&mdsc->cap_delay_lock);
4588 	INIT_LIST_HEAD(&mdsc->snap_flush_list);
4589 	spin_lock_init(&mdsc->snap_flush_lock);
4590 	mdsc->last_cap_flush_tid = 1;
4591 	INIT_LIST_HEAD(&mdsc->cap_flush_list);
4592 	INIT_LIST_HEAD(&mdsc->cap_dirty_migrating);
4593 	spin_lock_init(&mdsc->cap_dirty_lock);
4594 	init_waitqueue_head(&mdsc->cap_flushing_wq);
4595 	INIT_WORK(&mdsc->cap_reclaim_work, ceph_cap_reclaim_work);
4596 	err = ceph_metric_init(&mdsc->metric);
4597 	if (err)
4598 		goto err_mdsmap;
4599 
4600 	spin_lock_init(&mdsc->dentry_list_lock);
4601 	INIT_LIST_HEAD(&mdsc->dentry_leases);
4602 	INIT_LIST_HEAD(&mdsc->dentry_dir_leases);
4603 
4604 	ceph_caps_init(mdsc);
4605 	ceph_adjust_caps_max_min(mdsc, fsc->mount_options);
4606 
4607 	spin_lock_init(&mdsc->snapid_map_lock);
4608 	mdsc->snapid_map_tree = RB_ROOT;
4609 	INIT_LIST_HEAD(&mdsc->snapid_map_lru);
4610 
4611 	init_rwsem(&mdsc->pool_perm_rwsem);
4612 	mdsc->pool_perm_tree = RB_ROOT;
4613 
4614 	strscpy(mdsc->nodename, utsname()->nodename,
4615 		sizeof(mdsc->nodename));
4616 
4617 	fsc->mdsc = mdsc;
4618 	return 0;
4619 
4620 err_mdsmap:
4621 	kfree(mdsc->mdsmap);
4622 err_mdsc:
4623 	kfree(mdsc);
4624 	return err;
4625 }
4626 
4627 /*
4628  * Wait for safe replies on open mds requests.  If we time out, drop
4629  * all requests from the tree to avoid dangling dentry refs.
4630  */
4631 static void wait_requests(struct ceph_mds_client *mdsc)
4632 {
4633 	struct ceph_options *opts = mdsc->fsc->client->options;
4634 	struct ceph_mds_request *req;
4635 
4636 	mutex_lock(&mdsc->mutex);
4637 	if (__get_oldest_req(mdsc)) {
4638 		mutex_unlock(&mdsc->mutex);
4639 
4640 		dout("wait_requests waiting for requests\n");
4641 		wait_for_completion_timeout(&mdsc->safe_umount_waiters,
4642 				    ceph_timeout_jiffies(opts->mount_timeout));
4643 
4644 		/* tear down remaining requests */
4645 		mutex_lock(&mdsc->mutex);
4646 		while ((req = __get_oldest_req(mdsc))) {
4647 			dout("wait_requests timed out on tid %llu\n",
4648 			     req->r_tid);
4649 			list_del_init(&req->r_wait);
4650 			__unregister_request(mdsc, req);
4651 		}
4652 	}
4653 	mutex_unlock(&mdsc->mutex);
4654 	dout("wait_requests done\n");
4655 }
4656 
4657 void send_flush_mdlog(struct ceph_mds_session *s)
4658 {
4659 	struct ceph_msg *msg;
4660 
4661 	/*
4662 	 * Pre-luminous MDS crashes when it sees an unknown session request
4663 	 */
4664 	if (!CEPH_HAVE_FEATURE(s->s_con.peer_features, SERVER_LUMINOUS))
4665 		return;
4666 
4667 	mutex_lock(&s->s_mutex);
4668 	dout("request mdlog flush to mds%d (%s)s seq %lld\n", s->s_mds,
4669 	     ceph_session_state_name(s->s_state), s->s_seq);
4670 	msg = ceph_create_session_msg(CEPH_SESSION_REQUEST_FLUSH_MDLOG,
4671 				      s->s_seq);
4672 	if (!msg) {
4673 		pr_err("failed to request mdlog flush to mds%d (%s) seq %lld\n",
4674 		       s->s_mds, ceph_session_state_name(s->s_state), s->s_seq);
4675 	} else {
4676 		ceph_con_send(&s->s_con, msg);
4677 	}
4678 	mutex_unlock(&s->s_mutex);
4679 }
4680 
4681 /*
4682  * called before mount is ro, and before dentries are torn down.
4683  * (hmm, does this still race with new lookups?)
4684  */
4685 void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc)
4686 {
4687 	dout("pre_umount\n");
4688 	mdsc->stopping = 1;
4689 
4690 	ceph_mdsc_iterate_sessions(mdsc, send_flush_mdlog, true);
4691 	ceph_mdsc_iterate_sessions(mdsc, lock_unlock_session, false);
4692 	ceph_flush_dirty_caps(mdsc);
4693 	wait_requests(mdsc);
4694 
4695 	/*
4696 	 * wait for reply handlers to drop their request refs and
4697 	 * their inode/dcache refs
4698 	 */
4699 	ceph_msgr_flush();
4700 
4701 	ceph_cleanup_quotarealms_inodes(mdsc);
4702 }
4703 
4704 /*
4705  * wait for all write mds requests to flush.
4706  */
4707 static void wait_unsafe_requests(struct ceph_mds_client *mdsc, u64 want_tid)
4708 {
4709 	struct ceph_mds_request *req = NULL, *nextreq;
4710 	struct rb_node *n;
4711 
4712 	mutex_lock(&mdsc->mutex);
4713 	dout("wait_unsafe_requests want %lld\n", want_tid);
4714 restart:
4715 	req = __get_oldest_req(mdsc);
4716 	while (req && req->r_tid <= want_tid) {
4717 		/* find next request */
4718 		n = rb_next(&req->r_node);
4719 		if (n)
4720 			nextreq = rb_entry(n, struct ceph_mds_request, r_node);
4721 		else
4722 			nextreq = NULL;
4723 		if (req->r_op != CEPH_MDS_OP_SETFILELOCK &&
4724 		    (req->r_op & CEPH_MDS_OP_WRITE)) {
4725 			/* write op */
4726 			ceph_mdsc_get_request(req);
4727 			if (nextreq)
4728 				ceph_mdsc_get_request(nextreq);
4729 			mutex_unlock(&mdsc->mutex);
4730 			dout("wait_unsafe_requests  wait on %llu (want %llu)\n",
4731 			     req->r_tid, want_tid);
4732 			wait_for_completion(&req->r_safe_completion);
4733 			mutex_lock(&mdsc->mutex);
4734 			ceph_mdsc_put_request(req);
4735 			if (!nextreq)
4736 				break;  /* next dne before, so we're done! */
4737 			if (RB_EMPTY_NODE(&nextreq->r_node)) {
4738 				/* next request was removed from tree */
4739 				ceph_mdsc_put_request(nextreq);
4740 				goto restart;
4741 			}
4742 			ceph_mdsc_put_request(nextreq);  /* won't go away */
4743 		}
4744 		req = nextreq;
4745 	}
4746 	mutex_unlock(&mdsc->mutex);
4747 	dout("wait_unsafe_requests done\n");
4748 }
4749 
4750 void ceph_mdsc_sync(struct ceph_mds_client *mdsc)
4751 {
4752 	u64 want_tid, want_flush;
4753 
4754 	if (READ_ONCE(mdsc->fsc->mount_state) >= CEPH_MOUNT_SHUTDOWN)
4755 		return;
4756 
4757 	dout("sync\n");
4758 	mutex_lock(&mdsc->mutex);
4759 	want_tid = mdsc->last_tid;
4760 	mutex_unlock(&mdsc->mutex);
4761 
4762 	ceph_flush_dirty_caps(mdsc);
4763 	spin_lock(&mdsc->cap_dirty_lock);
4764 	want_flush = mdsc->last_cap_flush_tid;
4765 	if (!list_empty(&mdsc->cap_flush_list)) {
4766 		struct ceph_cap_flush *cf =
4767 			list_last_entry(&mdsc->cap_flush_list,
4768 					struct ceph_cap_flush, g_list);
4769 		cf->wake = true;
4770 	}
4771 	spin_unlock(&mdsc->cap_dirty_lock);
4772 
4773 	dout("sync want tid %lld flush_seq %lld\n",
4774 	     want_tid, want_flush);
4775 
4776 	wait_unsafe_requests(mdsc, want_tid);
4777 	wait_caps_flush(mdsc, want_flush);
4778 }
4779 
4780 /*
4781  * true if all sessions are closed, or we force unmount
4782  */
4783 static bool done_closing_sessions(struct ceph_mds_client *mdsc, int skipped)
4784 {
4785 	if (READ_ONCE(mdsc->fsc->mount_state) == CEPH_MOUNT_SHUTDOWN)
4786 		return true;
4787 	return atomic_read(&mdsc->num_sessions) <= skipped;
4788 }
4789 
4790 /*
4791  * called after sb is ro.
4792  */
4793 void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc)
4794 {
4795 	struct ceph_options *opts = mdsc->fsc->client->options;
4796 	struct ceph_mds_session *session;
4797 	int i;
4798 	int skipped = 0;
4799 
4800 	dout("close_sessions\n");
4801 
4802 	/* close sessions */
4803 	mutex_lock(&mdsc->mutex);
4804 	for (i = 0; i < mdsc->max_sessions; i++) {
4805 		session = __ceph_lookup_mds_session(mdsc, i);
4806 		if (!session)
4807 			continue;
4808 		mutex_unlock(&mdsc->mutex);
4809 		mutex_lock(&session->s_mutex);
4810 		if (__close_session(mdsc, session) <= 0)
4811 			skipped++;
4812 		mutex_unlock(&session->s_mutex);
4813 		ceph_put_mds_session(session);
4814 		mutex_lock(&mdsc->mutex);
4815 	}
4816 	mutex_unlock(&mdsc->mutex);
4817 
4818 	dout("waiting for sessions to close\n");
4819 	wait_event_timeout(mdsc->session_close_wq,
4820 			   done_closing_sessions(mdsc, skipped),
4821 			   ceph_timeout_jiffies(opts->mount_timeout));
4822 
4823 	/* tear down remaining sessions */
4824 	mutex_lock(&mdsc->mutex);
4825 	for (i = 0; i < mdsc->max_sessions; i++) {
4826 		if (mdsc->sessions[i]) {
4827 			session = ceph_get_mds_session(mdsc->sessions[i]);
4828 			__unregister_session(mdsc, session);
4829 			mutex_unlock(&mdsc->mutex);
4830 			mutex_lock(&session->s_mutex);
4831 			remove_session_caps(session);
4832 			mutex_unlock(&session->s_mutex);
4833 			ceph_put_mds_session(session);
4834 			mutex_lock(&mdsc->mutex);
4835 		}
4836 	}
4837 	WARN_ON(!list_empty(&mdsc->cap_delay_list));
4838 	mutex_unlock(&mdsc->mutex);
4839 
4840 	ceph_cleanup_snapid_map(mdsc);
4841 	ceph_cleanup_global_and_empty_realms(mdsc);
4842 
4843 	cancel_work_sync(&mdsc->cap_reclaim_work);
4844 	cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
4845 
4846 	dout("stopped\n");
4847 }
4848 
4849 void ceph_mdsc_force_umount(struct ceph_mds_client *mdsc)
4850 {
4851 	struct ceph_mds_session *session;
4852 	int mds;
4853 
4854 	dout("force umount\n");
4855 
4856 	mutex_lock(&mdsc->mutex);
4857 	for (mds = 0; mds < mdsc->max_sessions; mds++) {
4858 		session = __ceph_lookup_mds_session(mdsc, mds);
4859 		if (!session)
4860 			continue;
4861 
4862 		if (session->s_state == CEPH_MDS_SESSION_REJECTED)
4863 			__unregister_session(mdsc, session);
4864 		__wake_requests(mdsc, &session->s_waiting);
4865 		mutex_unlock(&mdsc->mutex);
4866 
4867 		mutex_lock(&session->s_mutex);
4868 		__close_session(mdsc, session);
4869 		if (session->s_state == CEPH_MDS_SESSION_CLOSING) {
4870 			cleanup_session_requests(mdsc, session);
4871 			remove_session_caps(session);
4872 		}
4873 		mutex_unlock(&session->s_mutex);
4874 		ceph_put_mds_session(session);
4875 
4876 		mutex_lock(&mdsc->mutex);
4877 		kick_requests(mdsc, mds);
4878 	}
4879 	__wake_requests(mdsc, &mdsc->waiting_for_map);
4880 	mutex_unlock(&mdsc->mutex);
4881 }
4882 
4883 static void ceph_mdsc_stop(struct ceph_mds_client *mdsc)
4884 {
4885 	dout("stop\n");
4886 	/*
4887 	 * Make sure the delayed work stopped before releasing
4888 	 * the resources.
4889 	 *
4890 	 * Because the cancel_delayed_work_sync() will only
4891 	 * guarantee that the work finishes executing. But the
4892 	 * delayed work will re-arm itself again after that.
4893 	 */
4894 	flush_delayed_work(&mdsc->delayed_work);
4895 
4896 	if (mdsc->mdsmap)
4897 		ceph_mdsmap_destroy(mdsc->mdsmap);
4898 	kfree(mdsc->sessions);
4899 	ceph_caps_finalize(mdsc);
4900 	ceph_pool_perm_destroy(mdsc);
4901 }
4902 
4903 void ceph_mdsc_destroy(struct ceph_fs_client *fsc)
4904 {
4905 	struct ceph_mds_client *mdsc = fsc->mdsc;
4906 	dout("mdsc_destroy %p\n", mdsc);
4907 
4908 	if (!mdsc)
4909 		return;
4910 
4911 	/* flush out any connection work with references to us */
4912 	ceph_msgr_flush();
4913 
4914 	ceph_mdsc_stop(mdsc);
4915 
4916 	ceph_metric_destroy(&mdsc->metric);
4917 
4918 	fsc->mdsc = NULL;
4919 	kfree(mdsc);
4920 	dout("mdsc_destroy %p done\n", mdsc);
4921 }
4922 
4923 void ceph_mdsc_handle_fsmap(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
4924 {
4925 	struct ceph_fs_client *fsc = mdsc->fsc;
4926 	const char *mds_namespace = fsc->mount_options->mds_namespace;
4927 	void *p = msg->front.iov_base;
4928 	void *end = p + msg->front.iov_len;
4929 	u32 epoch;
4930 	u32 num_fs;
4931 	u32 mount_fscid = (u32)-1;
4932 	int err = -EINVAL;
4933 
4934 	ceph_decode_need(&p, end, sizeof(u32), bad);
4935 	epoch = ceph_decode_32(&p);
4936 
4937 	dout("handle_fsmap epoch %u\n", epoch);
4938 
4939 	/* struct_v, struct_cv, map_len, epoch, legacy_client_fscid */
4940 	ceph_decode_skip_n(&p, end, 2 + sizeof(u32) * 3, bad);
4941 
4942 	ceph_decode_32_safe(&p, end, num_fs, bad);
4943 	while (num_fs-- > 0) {
4944 		void *info_p, *info_end;
4945 		u32 info_len;
4946 		u32 fscid, namelen;
4947 
4948 		ceph_decode_need(&p, end, 2 + sizeof(u32), bad);
4949 		p += 2;		// info_v, info_cv
4950 		info_len = ceph_decode_32(&p);
4951 		ceph_decode_need(&p, end, info_len, bad);
4952 		info_p = p;
4953 		info_end = p + info_len;
4954 		p = info_end;
4955 
4956 		ceph_decode_need(&info_p, info_end, sizeof(u32) * 2, bad);
4957 		fscid = ceph_decode_32(&info_p);
4958 		namelen = ceph_decode_32(&info_p);
4959 		ceph_decode_need(&info_p, info_end, namelen, bad);
4960 
4961 		if (mds_namespace &&
4962 		    strlen(mds_namespace) == namelen &&
4963 		    !strncmp(mds_namespace, (char *)info_p, namelen)) {
4964 			mount_fscid = fscid;
4965 			break;
4966 		}
4967 	}
4968 
4969 	ceph_monc_got_map(&fsc->client->monc, CEPH_SUB_FSMAP, epoch);
4970 	if (mount_fscid != (u32)-1) {
4971 		fsc->client->monc.fs_cluster_id = mount_fscid;
4972 		ceph_monc_want_map(&fsc->client->monc, CEPH_SUB_MDSMAP,
4973 				   0, true);
4974 		ceph_monc_renew_subs(&fsc->client->monc);
4975 	} else {
4976 		err = -ENOENT;
4977 		goto err_out;
4978 	}
4979 	return;
4980 
4981 bad:
4982 	pr_err("error decoding fsmap %d. Shutting down mount.\n", err);
4983 	ceph_umount_begin(mdsc->fsc->sb);
4984 err_out:
4985 	mutex_lock(&mdsc->mutex);
4986 	mdsc->mdsmap_err = err;
4987 	__wake_requests(mdsc, &mdsc->waiting_for_map);
4988 	mutex_unlock(&mdsc->mutex);
4989 }
4990 
4991 /*
4992  * handle mds map update.
4993  */
4994 void ceph_mdsc_handle_mdsmap(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
4995 {
4996 	u32 epoch;
4997 	u32 maplen;
4998 	void *p = msg->front.iov_base;
4999 	void *end = p + msg->front.iov_len;
5000 	struct ceph_mdsmap *newmap, *oldmap;
5001 	struct ceph_fsid fsid;
5002 	int err = -EINVAL;
5003 
5004 	ceph_decode_need(&p, end, sizeof(fsid)+2*sizeof(u32), bad);
5005 	ceph_decode_copy(&p, &fsid, sizeof(fsid));
5006 	if (ceph_check_fsid(mdsc->fsc->client, &fsid) < 0)
5007 		return;
5008 	epoch = ceph_decode_32(&p);
5009 	maplen = ceph_decode_32(&p);
5010 	dout("handle_map epoch %u len %d\n", epoch, (int)maplen);
5011 
5012 	/* do we need it? */
5013 	mutex_lock(&mdsc->mutex);
5014 	if (mdsc->mdsmap && epoch <= mdsc->mdsmap->m_epoch) {
5015 		dout("handle_map epoch %u <= our %u\n",
5016 		     epoch, mdsc->mdsmap->m_epoch);
5017 		mutex_unlock(&mdsc->mutex);
5018 		return;
5019 	}
5020 
5021 	newmap = ceph_mdsmap_decode(&p, end, ceph_msgr2(mdsc->fsc->client));
5022 	if (IS_ERR(newmap)) {
5023 		err = PTR_ERR(newmap);
5024 		goto bad_unlock;
5025 	}
5026 
5027 	/* swap into place */
5028 	if (mdsc->mdsmap) {
5029 		oldmap = mdsc->mdsmap;
5030 		mdsc->mdsmap = newmap;
5031 		check_new_map(mdsc, newmap, oldmap);
5032 		ceph_mdsmap_destroy(oldmap);
5033 	} else {
5034 		mdsc->mdsmap = newmap;  /* first mds map */
5035 	}
5036 	mdsc->fsc->max_file_size = min((loff_t)mdsc->mdsmap->m_max_file_size,
5037 					MAX_LFS_FILESIZE);
5038 
5039 	__wake_requests(mdsc, &mdsc->waiting_for_map);
5040 	ceph_monc_got_map(&mdsc->fsc->client->monc, CEPH_SUB_MDSMAP,
5041 			  mdsc->mdsmap->m_epoch);
5042 
5043 	mutex_unlock(&mdsc->mutex);
5044 	schedule_delayed(mdsc, 0);
5045 	return;
5046 
5047 bad_unlock:
5048 	mutex_unlock(&mdsc->mutex);
5049 bad:
5050 	pr_err("error decoding mdsmap %d. Shutting down mount.\n", err);
5051 	ceph_umount_begin(mdsc->fsc->sb);
5052 	return;
5053 }
5054 
5055 static struct ceph_connection *mds_get_con(struct ceph_connection *con)
5056 {
5057 	struct ceph_mds_session *s = con->private;
5058 
5059 	if (ceph_get_mds_session(s))
5060 		return con;
5061 	return NULL;
5062 }
5063 
5064 static void mds_put_con(struct ceph_connection *con)
5065 {
5066 	struct ceph_mds_session *s = con->private;
5067 
5068 	ceph_put_mds_session(s);
5069 }
5070 
5071 /*
5072  * if the client is unresponsive for long enough, the mds will kill
5073  * the session entirely.
5074  */
5075 static void mds_peer_reset(struct ceph_connection *con)
5076 {
5077 	struct ceph_mds_session *s = con->private;
5078 	struct ceph_mds_client *mdsc = s->s_mdsc;
5079 
5080 	pr_warn("mds%d closed our session\n", s->s_mds);
5081 	send_mds_reconnect(mdsc, s);
5082 }
5083 
5084 static void mds_dispatch(struct ceph_connection *con, struct ceph_msg *msg)
5085 {
5086 	struct ceph_mds_session *s = con->private;
5087 	struct ceph_mds_client *mdsc = s->s_mdsc;
5088 	int type = le16_to_cpu(msg->hdr.type);
5089 
5090 	mutex_lock(&mdsc->mutex);
5091 	if (__verify_registered_session(mdsc, s) < 0) {
5092 		mutex_unlock(&mdsc->mutex);
5093 		goto out;
5094 	}
5095 	mutex_unlock(&mdsc->mutex);
5096 
5097 	switch (type) {
5098 	case CEPH_MSG_MDS_MAP:
5099 		ceph_mdsc_handle_mdsmap(mdsc, msg);
5100 		break;
5101 	case CEPH_MSG_FS_MAP_USER:
5102 		ceph_mdsc_handle_fsmap(mdsc, msg);
5103 		break;
5104 	case CEPH_MSG_CLIENT_SESSION:
5105 		handle_session(s, msg);
5106 		break;
5107 	case CEPH_MSG_CLIENT_REPLY:
5108 		handle_reply(s, msg);
5109 		break;
5110 	case CEPH_MSG_CLIENT_REQUEST_FORWARD:
5111 		handle_forward(mdsc, s, msg);
5112 		break;
5113 	case CEPH_MSG_CLIENT_CAPS:
5114 		ceph_handle_caps(s, msg);
5115 		break;
5116 	case CEPH_MSG_CLIENT_SNAP:
5117 		ceph_handle_snap(mdsc, s, msg);
5118 		break;
5119 	case CEPH_MSG_CLIENT_LEASE:
5120 		handle_lease(mdsc, s, msg);
5121 		break;
5122 	case CEPH_MSG_CLIENT_QUOTA:
5123 		ceph_handle_quota(mdsc, s, msg);
5124 		break;
5125 
5126 	default:
5127 		pr_err("received unknown message type %d %s\n", type,
5128 		       ceph_msg_type_name(type));
5129 	}
5130 out:
5131 	ceph_msg_put(msg);
5132 }
5133 
5134 /*
5135  * authentication
5136  */
5137 
5138 /*
5139  * Note: returned pointer is the address of a structure that's
5140  * managed separately.  Caller must *not* attempt to free it.
5141  */
5142 static struct ceph_auth_handshake *
5143 mds_get_authorizer(struct ceph_connection *con, int *proto, int force_new)
5144 {
5145 	struct ceph_mds_session *s = con->private;
5146 	struct ceph_mds_client *mdsc = s->s_mdsc;
5147 	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
5148 	struct ceph_auth_handshake *auth = &s->s_auth;
5149 	int ret;
5150 
5151 	ret = __ceph_auth_get_authorizer(ac, auth, CEPH_ENTITY_TYPE_MDS,
5152 					 force_new, proto, NULL, NULL);
5153 	if (ret)
5154 		return ERR_PTR(ret);
5155 
5156 	return auth;
5157 }
5158 
5159 static int mds_add_authorizer_challenge(struct ceph_connection *con,
5160 				    void *challenge_buf, int challenge_buf_len)
5161 {
5162 	struct ceph_mds_session *s = con->private;
5163 	struct ceph_mds_client *mdsc = s->s_mdsc;
5164 	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
5165 
5166 	return ceph_auth_add_authorizer_challenge(ac, s->s_auth.authorizer,
5167 					    challenge_buf, challenge_buf_len);
5168 }
5169 
5170 static int mds_verify_authorizer_reply(struct ceph_connection *con)
5171 {
5172 	struct ceph_mds_session *s = con->private;
5173 	struct ceph_mds_client *mdsc = s->s_mdsc;
5174 	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
5175 	struct ceph_auth_handshake *auth = &s->s_auth;
5176 
5177 	return ceph_auth_verify_authorizer_reply(ac, auth->authorizer,
5178 		auth->authorizer_reply_buf, auth->authorizer_reply_buf_len,
5179 		NULL, NULL, NULL, NULL);
5180 }
5181 
5182 static int mds_invalidate_authorizer(struct ceph_connection *con)
5183 {
5184 	struct ceph_mds_session *s = con->private;
5185 	struct ceph_mds_client *mdsc = s->s_mdsc;
5186 	struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
5187 
5188 	ceph_auth_invalidate_authorizer(ac, CEPH_ENTITY_TYPE_MDS);
5189 
5190 	return ceph_monc_validate_auth(&mdsc->fsc->client->monc);
5191 }
5192 
5193 static int mds_get_auth_request(struct ceph_connection *con,
5194 				void *buf, int *buf_len,
5195 				void **authorizer, int *authorizer_len)
5196 {
5197 	struct ceph_mds_session *s = con->private;
5198 	struct ceph_auth_client *ac = s->s_mdsc->fsc->client->monc.auth;
5199 	struct ceph_auth_handshake *auth = &s->s_auth;
5200 	int ret;
5201 
5202 	ret = ceph_auth_get_authorizer(ac, auth, CEPH_ENTITY_TYPE_MDS,
5203 				       buf, buf_len);
5204 	if (ret)
5205 		return ret;
5206 
5207 	*authorizer = auth->authorizer_buf;
5208 	*authorizer_len = auth->authorizer_buf_len;
5209 	return 0;
5210 }
5211 
5212 static int mds_handle_auth_reply_more(struct ceph_connection *con,
5213 				      void *reply, int reply_len,
5214 				      void *buf, int *buf_len,
5215 				      void **authorizer, int *authorizer_len)
5216 {
5217 	struct ceph_mds_session *s = con->private;
5218 	struct ceph_auth_client *ac = s->s_mdsc->fsc->client->monc.auth;
5219 	struct ceph_auth_handshake *auth = &s->s_auth;
5220 	int ret;
5221 
5222 	ret = ceph_auth_handle_svc_reply_more(ac, auth, reply, reply_len,
5223 					      buf, buf_len);
5224 	if (ret)
5225 		return ret;
5226 
5227 	*authorizer = auth->authorizer_buf;
5228 	*authorizer_len = auth->authorizer_buf_len;
5229 	return 0;
5230 }
5231 
5232 static int mds_handle_auth_done(struct ceph_connection *con,
5233 				u64 global_id, void *reply, int reply_len,
5234 				u8 *session_key, int *session_key_len,
5235 				u8 *con_secret, int *con_secret_len)
5236 {
5237 	struct ceph_mds_session *s = con->private;
5238 	struct ceph_auth_client *ac = s->s_mdsc->fsc->client->monc.auth;
5239 	struct ceph_auth_handshake *auth = &s->s_auth;
5240 
5241 	return ceph_auth_handle_svc_reply_done(ac, auth, reply, reply_len,
5242 					       session_key, session_key_len,
5243 					       con_secret, con_secret_len);
5244 }
5245 
5246 static int mds_handle_auth_bad_method(struct ceph_connection *con,
5247 				      int used_proto, int result,
5248 				      const int *allowed_protos, int proto_cnt,
5249 				      const int *allowed_modes, int mode_cnt)
5250 {
5251 	struct ceph_mds_session *s = con->private;
5252 	struct ceph_mon_client *monc = &s->s_mdsc->fsc->client->monc;
5253 	int ret;
5254 
5255 	if (ceph_auth_handle_bad_authorizer(monc->auth, CEPH_ENTITY_TYPE_MDS,
5256 					    used_proto, result,
5257 					    allowed_protos, proto_cnt,
5258 					    allowed_modes, mode_cnt)) {
5259 		ret = ceph_monc_validate_auth(monc);
5260 		if (ret)
5261 			return ret;
5262 	}
5263 
5264 	return -EACCES;
5265 }
5266 
5267 static struct ceph_msg *mds_alloc_msg(struct ceph_connection *con,
5268 				struct ceph_msg_header *hdr, int *skip)
5269 {
5270 	struct ceph_msg *msg;
5271 	int type = (int) le16_to_cpu(hdr->type);
5272 	int front_len = (int) le32_to_cpu(hdr->front_len);
5273 
5274 	if (con->in_msg)
5275 		return con->in_msg;
5276 
5277 	*skip = 0;
5278 	msg = ceph_msg_new(type, front_len, GFP_NOFS, false);
5279 	if (!msg) {
5280 		pr_err("unable to allocate msg type %d len %d\n",
5281 		       type, front_len);
5282 		return NULL;
5283 	}
5284 
5285 	return msg;
5286 }
5287 
5288 static int mds_sign_message(struct ceph_msg *msg)
5289 {
5290        struct ceph_mds_session *s = msg->con->private;
5291        struct ceph_auth_handshake *auth = &s->s_auth;
5292 
5293        return ceph_auth_sign_message(auth, msg);
5294 }
5295 
5296 static int mds_check_message_signature(struct ceph_msg *msg)
5297 {
5298        struct ceph_mds_session *s = msg->con->private;
5299        struct ceph_auth_handshake *auth = &s->s_auth;
5300 
5301        return ceph_auth_check_message_signature(auth, msg);
5302 }
5303 
5304 static const struct ceph_connection_operations mds_con_ops = {
5305 	.get = mds_get_con,
5306 	.put = mds_put_con,
5307 	.alloc_msg = mds_alloc_msg,
5308 	.dispatch = mds_dispatch,
5309 	.peer_reset = mds_peer_reset,
5310 	.get_authorizer = mds_get_authorizer,
5311 	.add_authorizer_challenge = mds_add_authorizer_challenge,
5312 	.verify_authorizer_reply = mds_verify_authorizer_reply,
5313 	.invalidate_authorizer = mds_invalidate_authorizer,
5314 	.sign_message = mds_sign_message,
5315 	.check_message_signature = mds_check_message_signature,
5316 	.get_auth_request = mds_get_auth_request,
5317 	.handle_auth_reply_more = mds_handle_auth_reply_more,
5318 	.handle_auth_done = mds_handle_auth_done,
5319 	.handle_auth_bad_method = mds_handle_auth_bad_method,
5320 };
5321 
5322 /* eof */
5323