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TOMOYO Linux Cross Reference
Linux/fs/ceph/mds_client.c

Version: ~ [ linux-5.9.1 ] ~ [ linux-5.8.16 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.72 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.152 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.202 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.240 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.240 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 #include <linux/ceph/ceph_debug.h>
  2 
  3 #include <linux/fs.h>
  4 #include <linux/wait.h>
  5 #include <linux/slab.h>
  6 #include <linux/gfp.h>
  7 #include <linux/sched.h>
  8 #include <linux/debugfs.h>
  9 #include <linux/seq_file.h>
 10 
 11 #include "super.h"
 12 #include "mds_client.h"
 13 
 14 #include <linux/ceph/ceph_features.h>
 15 #include <linux/ceph/messenger.h>
 16 #include <linux/ceph/decode.h>
 17 #include <linux/ceph/pagelist.h>
 18 #include <linux/ceph/auth.h>
 19 #include <linux/ceph/debugfs.h>
 20 
 21 /*
 22  * A cluster of MDS (metadata server) daemons is responsible for
 23  * managing the file system namespace (the directory hierarchy and
 24  * inodes) and for coordinating shared access to storage.  Metadata is
 25  * partitioning hierarchically across a number of servers, and that
 26  * partition varies over time as the cluster adjusts the distribution
 27  * in order to balance load.
 28  *
 29  * The MDS client is primarily responsible to managing synchronous
 30  * metadata requests for operations like open, unlink, and so forth.
 31  * If there is a MDS failure, we find out about it when we (possibly
 32  * request and) receive a new MDS map, and can resubmit affected
 33  * requests.
 34  *
 35  * For the most part, though, we take advantage of a lossless
 36  * communications channel to the MDS, and do not need to worry about
 37  * timing out or resubmitting requests.
 38  *
 39  * We maintain a stateful "session" with each MDS we interact with.
 40  * Within each session, we sent periodic heartbeat messages to ensure
 41  * any capabilities or leases we have been issues remain valid.  If
 42  * the session times out and goes stale, our leases and capabilities
 43  * are no longer valid.
 44  */
 45 
 46 struct ceph_reconnect_state {
 47         int nr_caps;
 48         struct ceph_pagelist *pagelist;
 49         bool flock;
 50 };
 51 
 52 static void __wake_requests(struct ceph_mds_client *mdsc,
 53                             struct list_head *head);
 54 
 55 static const struct ceph_connection_operations mds_con_ops;
 56 
 57 
 58 /*
 59  * mds reply parsing
 60  */
 61 
 62 /*
 63  * parse individual inode info
 64  */
 65 static int parse_reply_info_in(void **p, void *end,
 66                                struct ceph_mds_reply_info_in *info,
 67                                u64 features)
 68 {
 69         int err = -EIO;
 70 
 71         info->in = *p;
 72         *p += sizeof(struct ceph_mds_reply_inode) +
 73                 sizeof(*info->in->fragtree.splits) *
 74                 le32_to_cpu(info->in->fragtree.nsplits);
 75 
 76         ceph_decode_32_safe(p, end, info->symlink_len, bad);
 77         ceph_decode_need(p, end, info->symlink_len, bad);
 78         info->symlink = *p;
 79         *p += info->symlink_len;
 80 
 81         if (features & CEPH_FEATURE_DIRLAYOUTHASH)
 82                 ceph_decode_copy_safe(p, end, &info->dir_layout,
 83                                       sizeof(info->dir_layout), bad);
 84         else
 85                 memset(&info->dir_layout, 0, sizeof(info->dir_layout));
 86 
 87         ceph_decode_32_safe(p, end, info->xattr_len, bad);
 88         ceph_decode_need(p, end, info->xattr_len, bad);
 89         info->xattr_data = *p;
 90         *p += info->xattr_len;
 91         return 0;
 92 bad:
 93         return err;
 94 }
 95 
 96 /*
 97  * parse a normal reply, which may contain a (dir+)dentry and/or a
 98  * target inode.
 99  */
100 static int parse_reply_info_trace(void **p, void *end,
101                                   struct ceph_mds_reply_info_parsed *info,
102                                   u64 features)
103 {
104         int err;
105 
106         if (info->head->is_dentry) {
107                 err = parse_reply_info_in(p, end, &info->diri, features);
108                 if (err < 0)
109                         goto out_bad;
110 
111                 if (unlikely(*p + sizeof(*info->dirfrag) > end))
112                         goto bad;
113                 info->dirfrag = *p;
114                 *p += sizeof(*info->dirfrag) +
115                         sizeof(u32)*le32_to_cpu(info->dirfrag->ndist);
116                 if (unlikely(*p > end))
117                         goto bad;
118 
119                 ceph_decode_32_safe(p, end, info->dname_len, bad);
120                 ceph_decode_need(p, end, info->dname_len, bad);
121                 info->dname = *p;
122                 *p += info->dname_len;
123                 info->dlease = *p;
124                 *p += sizeof(*info->dlease);
125         }
126 
127         if (info->head->is_target) {
128                 err = parse_reply_info_in(p, end, &info->targeti, features);
129                 if (err < 0)
130                         goto out_bad;
131         }
132 
133         if (unlikely(*p != end))
134                 goto bad;
135         return 0;
136 
137 bad:
138         err = -EIO;
139 out_bad:
140         pr_err("problem parsing mds trace %d\n", err);
141         return err;
142 }
143 
144 /*
145  * parse readdir results
146  */
147 static int parse_reply_info_dir(void **p, void *end,
148                                 struct ceph_mds_reply_info_parsed *info,
149                                 u64 features)
150 {
151         u32 num, i = 0;
152         int err;
153 
154         info->dir_dir = *p;
155         if (*p + sizeof(*info->dir_dir) > end)
156                 goto bad;
157         *p += sizeof(*info->dir_dir) +
158                 sizeof(u32)*le32_to_cpu(info->dir_dir->ndist);
159         if (*p > end)
160                 goto bad;
161 
162         ceph_decode_need(p, end, sizeof(num) + 2, bad);
163         num = ceph_decode_32(p);
164         info->dir_end = ceph_decode_8(p);
165         info->dir_complete = ceph_decode_8(p);
166         if (num == 0)
167                 goto done;
168 
169         BUG_ON(!info->dir_in);
170         info->dir_dname = (void *)(info->dir_in + num);
171         info->dir_dname_len = (void *)(info->dir_dname + num);
172         info->dir_dlease = (void *)(info->dir_dname_len + num);
173         if ((unsigned long)(info->dir_dlease + num) >
174             (unsigned long)info->dir_in + info->dir_buf_size) {
175                 pr_err("dir contents are larger than expected\n");
176                 WARN_ON(1);
177                 goto bad;
178         }
179 
180         info->dir_nr = num;
181         while (num) {
182                 /* dentry */
183                 ceph_decode_need(p, end, sizeof(u32)*2, bad);
184                 info->dir_dname_len[i] = ceph_decode_32(p);
185                 ceph_decode_need(p, end, info->dir_dname_len[i], bad);
186                 info->dir_dname[i] = *p;
187                 *p += info->dir_dname_len[i];
188                 dout("parsed dir dname '%.*s'\n", info->dir_dname_len[i],
189                      info->dir_dname[i]);
190                 info->dir_dlease[i] = *p;
191                 *p += sizeof(struct ceph_mds_reply_lease);
192 
193                 /* inode */
194                 err = parse_reply_info_in(p, end, &info->dir_in[i], features);
195                 if (err < 0)
196                         goto out_bad;
197                 i++;
198                 num--;
199         }
200 
201 done:
202         if (*p != end)
203                 goto bad;
204         return 0;
205 
206 bad:
207         err = -EIO;
208 out_bad:
209         pr_err("problem parsing dir contents %d\n", err);
210         return err;
211 }
212 
213 /*
214  * parse fcntl F_GETLK results
215  */
216 static int parse_reply_info_filelock(void **p, void *end,
217                                      struct ceph_mds_reply_info_parsed *info,
218                                      u64 features)
219 {
220         if (*p + sizeof(*info->filelock_reply) > end)
221                 goto bad;
222 
223         info->filelock_reply = *p;
224         *p += sizeof(*info->filelock_reply);
225 
226         if (unlikely(*p != end))
227                 goto bad;
228         return 0;
229 
230 bad:
231         return -EIO;
232 }
233 
234 /*
235  * parse create results
236  */
237 static int parse_reply_info_create(void **p, void *end,
238                                   struct ceph_mds_reply_info_parsed *info,
239                                   u64 features)
240 {
241         if (features & CEPH_FEATURE_REPLY_CREATE_INODE) {
242                 if (*p == end) {
243                         info->has_create_ino = false;
244                 } else {
245                         info->has_create_ino = true;
246                         info->ino = ceph_decode_64(p);
247                 }
248         }
249 
250         if (unlikely(*p != end))
251                 goto bad;
252         return 0;
253 
254 bad:
255         return -EIO;
256 }
257 
258 /*
259  * parse extra results
260  */
261 static int parse_reply_info_extra(void **p, void *end,
262                                   struct ceph_mds_reply_info_parsed *info,
263                                   u64 features)
264 {
265         if (info->head->op == CEPH_MDS_OP_GETFILELOCK)
266                 return parse_reply_info_filelock(p, end, info, features);
267         else if (info->head->op == CEPH_MDS_OP_READDIR ||
268                  info->head->op == CEPH_MDS_OP_LSSNAP)
269                 return parse_reply_info_dir(p, end, info, features);
270         else if (info->head->op == CEPH_MDS_OP_CREATE)
271                 return parse_reply_info_create(p, end, info, features);
272         else
273                 return -EIO;
274 }
275 
276 /*
277  * parse entire mds reply
278  */
279 static int parse_reply_info(struct ceph_msg *msg,
280                             struct ceph_mds_reply_info_parsed *info,
281                             u64 features)
282 {
283         void *p, *end;
284         u32 len;
285         int err;
286 
287         info->head = msg->front.iov_base;
288         p = msg->front.iov_base + sizeof(struct ceph_mds_reply_head);
289         end = p + msg->front.iov_len - sizeof(struct ceph_mds_reply_head);
290 
291         /* trace */
292         ceph_decode_32_safe(&p, end, len, bad);
293         if (len > 0) {
294                 ceph_decode_need(&p, end, len, bad);
295                 err = parse_reply_info_trace(&p, p+len, info, features);
296                 if (err < 0)
297                         goto out_bad;
298         }
299 
300         /* extra */
301         ceph_decode_32_safe(&p, end, len, bad);
302         if (len > 0) {
303                 ceph_decode_need(&p, end, len, bad);
304                 err = parse_reply_info_extra(&p, p+len, info, features);
305                 if (err < 0)
306                         goto out_bad;
307         }
308 
309         /* snap blob */
310         ceph_decode_32_safe(&p, end, len, bad);
311         info->snapblob_len = len;
312         info->snapblob = p;
313         p += len;
314 
315         if (p != end)
316                 goto bad;
317         return 0;
318 
319 bad:
320         err = -EIO;
321 out_bad:
322         pr_err("mds parse_reply err %d\n", err);
323         return err;
324 }
325 
326 static void destroy_reply_info(struct ceph_mds_reply_info_parsed *info)
327 {
328         if (!info->dir_in)
329                 return;
330         free_pages((unsigned long)info->dir_in, get_order(info->dir_buf_size));
331 }
332 
333 
334 /*
335  * sessions
336  */
337 static const char *session_state_name(int s)
338 {
339         switch (s) {
340         case CEPH_MDS_SESSION_NEW: return "new";
341         case CEPH_MDS_SESSION_OPENING: return "opening";
342         case CEPH_MDS_SESSION_OPEN: return "open";
343         case CEPH_MDS_SESSION_HUNG: return "hung";
344         case CEPH_MDS_SESSION_CLOSING: return "closing";
345         case CEPH_MDS_SESSION_RESTARTING: return "restarting";
346         case CEPH_MDS_SESSION_RECONNECTING: return "reconnecting";
347         default: return "???";
348         }
349 }
350 
351 static struct ceph_mds_session *get_session(struct ceph_mds_session *s)
352 {
353         if (atomic_inc_not_zero(&s->s_ref)) {
354                 dout("mdsc get_session %p %d -> %d\n", s,
355                      atomic_read(&s->s_ref)-1, atomic_read(&s->s_ref));
356                 return s;
357         } else {
358                 dout("mdsc get_session %p 0 -- FAIL", s);
359                 return NULL;
360         }
361 }
362 
363 void ceph_put_mds_session(struct ceph_mds_session *s)
364 {
365         dout("mdsc put_session %p %d -> %d\n", s,
366              atomic_read(&s->s_ref), atomic_read(&s->s_ref)-1);
367         if (atomic_dec_and_test(&s->s_ref)) {
368                 if (s->s_auth.authorizer)
369                         ceph_auth_destroy_authorizer(
370                                 s->s_mdsc->fsc->client->monc.auth,
371                                 s->s_auth.authorizer);
372                 kfree(s);
373         }
374 }
375 
376 /*
377  * called under mdsc->mutex
378  */
379 struct ceph_mds_session *__ceph_lookup_mds_session(struct ceph_mds_client *mdsc,
380                                                    int mds)
381 {
382         struct ceph_mds_session *session;
383 
384         if (mds >= mdsc->max_sessions || mdsc->sessions[mds] == NULL)
385                 return NULL;
386         session = mdsc->sessions[mds];
387         dout("lookup_mds_session %p %d\n", session,
388              atomic_read(&session->s_ref));
389         get_session(session);
390         return session;
391 }
392 
393 static bool __have_session(struct ceph_mds_client *mdsc, int mds)
394 {
395         if (mds >= mdsc->max_sessions)
396                 return false;
397         return mdsc->sessions[mds];
398 }
399 
400 static int __verify_registered_session(struct ceph_mds_client *mdsc,
401                                        struct ceph_mds_session *s)
402 {
403         if (s->s_mds >= mdsc->max_sessions ||
404             mdsc->sessions[s->s_mds] != s)
405                 return -ENOENT;
406         return 0;
407 }
408 
409 /*
410  * create+register a new session for given mds.
411  * called under mdsc->mutex.
412  */
413 static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
414                                                  int mds)
415 {
416         struct ceph_mds_session *s;
417 
418         if (mds >= mdsc->mdsmap->m_max_mds)
419                 return ERR_PTR(-EINVAL);
420 
421         s = kzalloc(sizeof(*s), GFP_NOFS);
422         if (!s)
423                 return ERR_PTR(-ENOMEM);
424         s->s_mdsc = mdsc;
425         s->s_mds = mds;
426         s->s_state = CEPH_MDS_SESSION_NEW;
427         s->s_ttl = 0;
428         s->s_seq = 0;
429         mutex_init(&s->s_mutex);
430 
431         ceph_con_init(&s->s_con, s, &mds_con_ops, &mdsc->fsc->client->msgr);
432 
433         spin_lock_init(&s->s_gen_ttl_lock);
434         s->s_cap_gen = 0;
435         s->s_cap_ttl = jiffies - 1;
436 
437         spin_lock_init(&s->s_cap_lock);
438         s->s_renew_requested = 0;
439         s->s_renew_seq = 0;
440         INIT_LIST_HEAD(&s->s_caps);
441         s->s_nr_caps = 0;
442         s->s_trim_caps = 0;
443         atomic_set(&s->s_ref, 1);
444         INIT_LIST_HEAD(&s->s_waiting);
445         INIT_LIST_HEAD(&s->s_unsafe);
446         s->s_num_cap_releases = 0;
447         s->s_cap_reconnect = 0;
448         s->s_cap_iterator = NULL;
449         INIT_LIST_HEAD(&s->s_cap_releases);
450         INIT_LIST_HEAD(&s->s_cap_releases_done);
451         INIT_LIST_HEAD(&s->s_cap_flushing);
452         INIT_LIST_HEAD(&s->s_cap_snaps_flushing);
453 
454         dout("register_session mds%d\n", mds);
455         if (mds >= mdsc->max_sessions) {
456                 int newmax = 1 << get_count_order(mds+1);
457                 struct ceph_mds_session **sa;
458 
459                 dout("register_session realloc to %d\n", newmax);
460                 sa = kcalloc(newmax, sizeof(void *), GFP_NOFS);
461                 if (sa == NULL)
462                         goto fail_realloc;
463                 if (mdsc->sessions) {
464                         memcpy(sa, mdsc->sessions,
465                                mdsc->max_sessions * sizeof(void *));
466                         kfree(mdsc->sessions);
467                 }
468                 mdsc->sessions = sa;
469                 mdsc->max_sessions = newmax;
470         }
471         mdsc->sessions[mds] = s;
472         atomic_inc(&s->s_ref);  /* one ref to sessions[], one to caller */
473 
474         ceph_con_open(&s->s_con, CEPH_ENTITY_TYPE_MDS, mds,
475                       ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
476 
477         return s;
478 
479 fail_realloc:
480         kfree(s);
481         return ERR_PTR(-ENOMEM);
482 }
483 
484 /*
485  * called under mdsc->mutex
486  */
487 static void __unregister_session(struct ceph_mds_client *mdsc,
488                                struct ceph_mds_session *s)
489 {
490         dout("__unregister_session mds%d %p\n", s->s_mds, s);
491         BUG_ON(mdsc->sessions[s->s_mds] != s);
492         mdsc->sessions[s->s_mds] = NULL;
493         ceph_con_close(&s->s_con);
494         ceph_put_mds_session(s);
495 }
496 
497 /*
498  * drop session refs in request.
499  *
500  * should be last request ref, or hold mdsc->mutex
501  */
502 static void put_request_session(struct ceph_mds_request *req)
503 {
504         if (req->r_session) {
505                 ceph_put_mds_session(req->r_session);
506                 req->r_session = NULL;
507         }
508 }
509 
510 void ceph_mdsc_release_request(struct kref *kref)
511 {
512         struct ceph_mds_request *req = container_of(kref,
513                                                     struct ceph_mds_request,
514                                                     r_kref);
515         destroy_reply_info(&req->r_reply_info);
516         if (req->r_request)
517                 ceph_msg_put(req->r_request);
518         if (req->r_reply)
519                 ceph_msg_put(req->r_reply);
520         if (req->r_inode) {
521                 ceph_put_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
522                 iput(req->r_inode);
523         }
524         if (req->r_locked_dir)
525                 ceph_put_cap_refs(ceph_inode(req->r_locked_dir), CEPH_CAP_PIN);
526         if (req->r_target_inode)
527                 iput(req->r_target_inode);
528         if (req->r_dentry)
529                 dput(req->r_dentry);
530         if (req->r_old_dentry)
531                 dput(req->r_old_dentry);
532         if (req->r_old_dentry_dir) {
533                 /*
534                  * track (and drop pins for) r_old_dentry_dir
535                  * separately, since r_old_dentry's d_parent may have
536                  * changed between the dir mutex being dropped and
537                  * this request being freed.
538                  */
539                 ceph_put_cap_refs(ceph_inode(req->r_old_dentry_dir),
540                                   CEPH_CAP_PIN);
541                 iput(req->r_old_dentry_dir);
542         }
543         kfree(req->r_path1);
544         kfree(req->r_path2);
545         put_request_session(req);
546         ceph_unreserve_caps(req->r_mdsc, &req->r_caps_reservation);
547         kfree(req);
548 }
549 
550 /*
551  * lookup session, bump ref if found.
552  *
553  * called under mdsc->mutex.
554  */
555 static struct ceph_mds_request *__lookup_request(struct ceph_mds_client *mdsc,
556                                              u64 tid)
557 {
558         struct ceph_mds_request *req;
559         struct rb_node *n = mdsc->request_tree.rb_node;
560 
561         while (n) {
562                 req = rb_entry(n, struct ceph_mds_request, r_node);
563                 if (tid < req->r_tid)
564                         n = n->rb_left;
565                 else if (tid > req->r_tid)
566                         n = n->rb_right;
567                 else {
568                         ceph_mdsc_get_request(req);
569                         return req;
570                 }
571         }
572         return NULL;
573 }
574 
575 static void __insert_request(struct ceph_mds_client *mdsc,
576                              struct ceph_mds_request *new)
577 {
578         struct rb_node **p = &mdsc->request_tree.rb_node;
579         struct rb_node *parent = NULL;
580         struct ceph_mds_request *req = NULL;
581 
582         while (*p) {
583                 parent = *p;
584                 req = rb_entry(parent, struct ceph_mds_request, r_node);
585                 if (new->r_tid < req->r_tid)
586                         p = &(*p)->rb_left;
587                 else if (new->r_tid > req->r_tid)
588                         p = &(*p)->rb_right;
589                 else
590                         BUG();
591         }
592 
593         rb_link_node(&new->r_node, parent, p);
594         rb_insert_color(&new->r_node, &mdsc->request_tree);
595 }
596 
597 /*
598  * Register an in-flight request, and assign a tid.  Link to directory
599  * are modifying (if any).
600  *
601  * Called under mdsc->mutex.
602  */
603 static void __register_request(struct ceph_mds_client *mdsc,
604                                struct ceph_mds_request *req,
605                                struct inode *dir)
606 {
607         req->r_tid = ++mdsc->last_tid;
608         if (req->r_num_caps)
609                 ceph_reserve_caps(mdsc, &req->r_caps_reservation,
610                                   req->r_num_caps);
611         dout("__register_request %p tid %lld\n", req, req->r_tid);
612         ceph_mdsc_get_request(req);
613         __insert_request(mdsc, req);
614 
615         req->r_uid = current_fsuid();
616         req->r_gid = current_fsgid();
617 
618         if (dir) {
619                 struct ceph_inode_info *ci = ceph_inode(dir);
620 
621                 ihold(dir);
622                 spin_lock(&ci->i_unsafe_lock);
623                 req->r_unsafe_dir = dir;
624                 list_add_tail(&req->r_unsafe_dir_item, &ci->i_unsafe_dirops);
625                 spin_unlock(&ci->i_unsafe_lock);
626         }
627 }
628 
629 static void __unregister_request(struct ceph_mds_client *mdsc,
630                                  struct ceph_mds_request *req)
631 {
632         dout("__unregister_request %p tid %lld\n", req, req->r_tid);
633         rb_erase(&req->r_node, &mdsc->request_tree);
634         RB_CLEAR_NODE(&req->r_node);
635 
636         if (req->r_unsafe_dir) {
637                 struct ceph_inode_info *ci = ceph_inode(req->r_unsafe_dir);
638 
639                 spin_lock(&ci->i_unsafe_lock);
640                 list_del_init(&req->r_unsafe_dir_item);
641                 spin_unlock(&ci->i_unsafe_lock);
642 
643                 iput(req->r_unsafe_dir);
644                 req->r_unsafe_dir = NULL;
645         }
646 
647         complete_all(&req->r_safe_completion);
648 
649         ceph_mdsc_put_request(req);
650 }
651 
652 /*
653  * Choose mds to send request to next.  If there is a hint set in the
654  * request (e.g., due to a prior forward hint from the mds), use that.
655  * Otherwise, consult frag tree and/or caps to identify the
656  * appropriate mds.  If all else fails, choose randomly.
657  *
658  * Called under mdsc->mutex.
659  */
660 static struct dentry *get_nonsnap_parent(struct dentry *dentry)
661 {
662         /*
663          * we don't need to worry about protecting the d_parent access
664          * here because we never renaming inside the snapped namespace
665          * except to resplice to another snapdir, and either the old or new
666          * result is a valid result.
667          */
668         while (!IS_ROOT(dentry) && ceph_snap(dentry->d_inode) != CEPH_NOSNAP)
669                 dentry = dentry->d_parent;
670         return dentry;
671 }
672 
673 static int __choose_mds(struct ceph_mds_client *mdsc,
674                         struct ceph_mds_request *req)
675 {
676         struct inode *inode;
677         struct ceph_inode_info *ci;
678         struct ceph_cap *cap;
679         int mode = req->r_direct_mode;
680         int mds = -1;
681         u32 hash = req->r_direct_hash;
682         bool is_hash = req->r_direct_is_hash;
683 
684         /*
685          * is there a specific mds we should try?  ignore hint if we have
686          * no session and the mds is not up (active or recovering).
687          */
688         if (req->r_resend_mds >= 0 &&
689             (__have_session(mdsc, req->r_resend_mds) ||
690              ceph_mdsmap_get_state(mdsc->mdsmap, req->r_resend_mds) > 0)) {
691                 dout("choose_mds using resend_mds mds%d\n",
692                      req->r_resend_mds);
693                 return req->r_resend_mds;
694         }
695 
696         if (mode == USE_RANDOM_MDS)
697                 goto random;
698 
699         inode = NULL;
700         if (req->r_inode) {
701                 inode = req->r_inode;
702         } else if (req->r_dentry) {
703                 /* ignore race with rename; old or new d_parent is okay */
704                 struct dentry *parent = req->r_dentry->d_parent;
705                 struct inode *dir = parent->d_inode;
706 
707                 if (dir->i_sb != mdsc->fsc->sb) {
708                         /* not this fs! */
709                         inode = req->r_dentry->d_inode;
710                 } else if (ceph_snap(dir) != CEPH_NOSNAP) {
711                         /* direct snapped/virtual snapdir requests
712                          * based on parent dir inode */
713                         struct dentry *dn = get_nonsnap_parent(parent);
714                         inode = dn->d_inode;
715                         dout("__choose_mds using nonsnap parent %p\n", inode);
716                 } else {
717                         /* dentry target */
718                         inode = req->r_dentry->d_inode;
719                         if (!inode || mode == USE_AUTH_MDS) {
720                                 /* dir + name */
721                                 inode = dir;
722                                 hash = ceph_dentry_hash(dir, req->r_dentry);
723                                 is_hash = true;
724                         }
725                 }
726         }
727 
728         dout("__choose_mds %p is_hash=%d (%d) mode %d\n", inode, (int)is_hash,
729              (int)hash, mode);
730         if (!inode)
731                 goto random;
732         ci = ceph_inode(inode);
733 
734         if (is_hash && S_ISDIR(inode->i_mode)) {
735                 struct ceph_inode_frag frag;
736                 int found;
737 
738                 ceph_choose_frag(ci, hash, &frag, &found);
739                 if (found) {
740                         if (mode == USE_ANY_MDS && frag.ndist > 0) {
741                                 u8 r;
742 
743                                 /* choose a random replica */
744                                 get_random_bytes(&r, 1);
745                                 r %= frag.ndist;
746                                 mds = frag.dist[r];
747                                 dout("choose_mds %p %llx.%llx "
748                                      "frag %u mds%d (%d/%d)\n",
749                                      inode, ceph_vinop(inode),
750                                      frag.frag, mds,
751                                      (int)r, frag.ndist);
752                                 if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
753                                     CEPH_MDS_STATE_ACTIVE)
754                                         return mds;
755                         }
756 
757                         /* since this file/dir wasn't known to be
758                          * replicated, then we want to look for the
759                          * authoritative mds. */
760                         mode = USE_AUTH_MDS;
761                         if (frag.mds >= 0) {
762                                 /* choose auth mds */
763                                 mds = frag.mds;
764                                 dout("choose_mds %p %llx.%llx "
765                                      "frag %u mds%d (auth)\n",
766                                      inode, ceph_vinop(inode), frag.frag, mds);
767                                 if (ceph_mdsmap_get_state(mdsc->mdsmap, mds) >=
768                                     CEPH_MDS_STATE_ACTIVE)
769                                         return mds;
770                         }
771                 }
772         }
773 
774         spin_lock(&ci->i_ceph_lock);
775         cap = NULL;
776         if (mode == USE_AUTH_MDS)
777                 cap = ci->i_auth_cap;
778         if (!cap && !RB_EMPTY_ROOT(&ci->i_caps))
779                 cap = rb_entry(rb_first(&ci->i_caps), struct ceph_cap, ci_node);
780         if (!cap) {
781                 spin_unlock(&ci->i_ceph_lock);
782                 goto random;
783         }
784         mds = cap->session->s_mds;
785         dout("choose_mds %p %llx.%llx mds%d (%scap %p)\n",
786              inode, ceph_vinop(inode), mds,
787              cap == ci->i_auth_cap ? "auth " : "", cap);
788         spin_unlock(&ci->i_ceph_lock);
789         return mds;
790 
791 random:
792         mds = ceph_mdsmap_get_random_mds(mdsc->mdsmap);
793         dout("choose_mds chose random mds%d\n", mds);
794         return mds;
795 }
796 
797 
798 /*
799  * session messages
800  */
801 static struct ceph_msg *create_session_msg(u32 op, u64 seq)
802 {
803         struct ceph_msg *msg;
804         struct ceph_mds_session_head *h;
805 
806         msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h), GFP_NOFS,
807                            false);
808         if (!msg) {
809                 pr_err("create_session_msg ENOMEM creating msg\n");
810                 return NULL;
811         }
812         h = msg->front.iov_base;
813         h->op = cpu_to_le32(op);
814         h->seq = cpu_to_le64(seq);
815         return msg;
816 }
817 
818 /*
819  * send session open request.
820  *
821  * called under mdsc->mutex
822  */
823 static int __open_session(struct ceph_mds_client *mdsc,
824                           struct ceph_mds_session *session)
825 {
826         struct ceph_msg *msg;
827         int mstate;
828         int mds = session->s_mds;
829 
830         /* wait for mds to go active? */
831         mstate = ceph_mdsmap_get_state(mdsc->mdsmap, mds);
832         dout("open_session to mds%d (%s)\n", mds,
833              ceph_mds_state_name(mstate));
834         session->s_state = CEPH_MDS_SESSION_OPENING;
835         session->s_renew_requested = jiffies;
836 
837         /* send connect message */
838         msg = create_session_msg(CEPH_SESSION_REQUEST_OPEN, session->s_seq);
839         if (!msg)
840                 return -ENOMEM;
841         ceph_con_send(&session->s_con, msg);
842         return 0;
843 }
844 
845 /*
846  * open sessions for any export targets for the given mds
847  *
848  * called under mdsc->mutex
849  */
850 static struct ceph_mds_session *
851 __open_export_target_session(struct ceph_mds_client *mdsc, int target)
852 {
853         struct ceph_mds_session *session;
854 
855         session = __ceph_lookup_mds_session(mdsc, target);
856         if (!session) {
857                 session = register_session(mdsc, target);
858                 if (IS_ERR(session))
859                         return session;
860         }
861         if (session->s_state == CEPH_MDS_SESSION_NEW ||
862             session->s_state == CEPH_MDS_SESSION_CLOSING)
863                 __open_session(mdsc, session);
864 
865         return session;
866 }
867 
868 struct ceph_mds_session *
869 ceph_mdsc_open_export_target_session(struct ceph_mds_client *mdsc, int target)
870 {
871         struct ceph_mds_session *session;
872 
873         dout("open_export_target_session to mds%d\n", target);
874 
875         mutex_lock(&mdsc->mutex);
876         session = __open_export_target_session(mdsc, target);
877         mutex_unlock(&mdsc->mutex);
878 
879         return session;
880 }
881 
882 static void __open_export_target_sessions(struct ceph_mds_client *mdsc,
883                                           struct ceph_mds_session *session)
884 {
885         struct ceph_mds_info *mi;
886         struct ceph_mds_session *ts;
887         int i, mds = session->s_mds;
888 
889         if (mds >= mdsc->mdsmap->m_max_mds)
890                 return;
891 
892         mi = &mdsc->mdsmap->m_info[mds];
893         dout("open_export_target_sessions for mds%d (%d targets)\n",
894              session->s_mds, mi->num_export_targets);
895 
896         for (i = 0; i < mi->num_export_targets; i++) {
897                 ts = __open_export_target_session(mdsc, mi->export_targets[i]);
898                 if (!IS_ERR(ts))
899                         ceph_put_mds_session(ts);
900         }
901 }
902 
903 void ceph_mdsc_open_export_target_sessions(struct ceph_mds_client *mdsc,
904                                            struct ceph_mds_session *session)
905 {
906         mutex_lock(&mdsc->mutex);
907         __open_export_target_sessions(mdsc, session);
908         mutex_unlock(&mdsc->mutex);
909 }
910 
911 /*
912  * session caps
913  */
914 
915 /*
916  * Free preallocated cap messages assigned to this session
917  */
918 static void cleanup_cap_releases(struct ceph_mds_session *session)
919 {
920         struct ceph_msg *msg;
921 
922         spin_lock(&session->s_cap_lock);
923         while (!list_empty(&session->s_cap_releases)) {
924                 msg = list_first_entry(&session->s_cap_releases,
925                                        struct ceph_msg, list_head);
926                 list_del_init(&msg->list_head);
927                 ceph_msg_put(msg);
928         }
929         while (!list_empty(&session->s_cap_releases_done)) {
930                 msg = list_first_entry(&session->s_cap_releases_done,
931                                        struct ceph_msg, list_head);
932                 list_del_init(&msg->list_head);
933                 ceph_msg_put(msg);
934         }
935         spin_unlock(&session->s_cap_lock);
936 }
937 
938 /*
939  * Helper to safely iterate over all caps associated with a session, with
940  * special care taken to handle a racing __ceph_remove_cap().
941  *
942  * Caller must hold session s_mutex.
943  */
944 static int iterate_session_caps(struct ceph_mds_session *session,
945                                  int (*cb)(struct inode *, struct ceph_cap *,
946                                             void *), void *arg)
947 {
948         struct list_head *p;
949         struct ceph_cap *cap;
950         struct inode *inode, *last_inode = NULL;
951         struct ceph_cap *old_cap = NULL;
952         int ret;
953 
954         dout("iterate_session_caps %p mds%d\n", session, session->s_mds);
955         spin_lock(&session->s_cap_lock);
956         p = session->s_caps.next;
957         while (p != &session->s_caps) {
958                 cap = list_entry(p, struct ceph_cap, session_caps);
959                 inode = igrab(&cap->ci->vfs_inode);
960                 if (!inode) {
961                         p = p->next;
962                         continue;
963                 }
964                 session->s_cap_iterator = cap;
965                 spin_unlock(&session->s_cap_lock);
966 
967                 if (last_inode) {
968                         iput(last_inode);
969                         last_inode = NULL;
970                 }
971                 if (old_cap) {
972                         ceph_put_cap(session->s_mdsc, old_cap);
973                         old_cap = NULL;
974                 }
975 
976                 ret = cb(inode, cap, arg);
977                 last_inode = inode;
978 
979                 spin_lock(&session->s_cap_lock);
980                 p = p->next;
981                 if (cap->ci == NULL) {
982                         dout("iterate_session_caps  finishing cap %p removal\n",
983                              cap);
984                         BUG_ON(cap->session != session);
985                         list_del_init(&cap->session_caps);
986                         session->s_nr_caps--;
987                         cap->session = NULL;
988                         old_cap = cap;  /* put_cap it w/o locks held */
989                 }
990                 if (ret < 0)
991                         goto out;
992         }
993         ret = 0;
994 out:
995         session->s_cap_iterator = NULL;
996         spin_unlock(&session->s_cap_lock);
997 
998         if (last_inode)
999                 iput(last_inode);
1000         if (old_cap)
1001                 ceph_put_cap(session->s_mdsc, old_cap);
1002 
1003         return ret;
1004 }
1005 
1006 static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
1007                                   void *arg)
1008 {
1009         struct ceph_inode_info *ci = ceph_inode(inode);
1010         int drop = 0;
1011 
1012         dout("removing cap %p, ci is %p, inode is %p\n",
1013              cap, ci, &ci->vfs_inode);
1014         spin_lock(&ci->i_ceph_lock);
1015         __ceph_remove_cap(cap, false);
1016         if (!__ceph_is_any_real_caps(ci)) {
1017                 struct ceph_mds_client *mdsc =
1018                         ceph_sb_to_client(inode->i_sb)->mdsc;
1019 
1020                 spin_lock(&mdsc->cap_dirty_lock);
1021                 if (!list_empty(&ci->i_dirty_item)) {
1022                         pr_info(" dropping dirty %s state for %p %lld\n",
1023                                 ceph_cap_string(ci->i_dirty_caps),
1024                                 inode, ceph_ino(inode));
1025                         ci->i_dirty_caps = 0;
1026                         list_del_init(&ci->i_dirty_item);
1027                         drop = 1;
1028                 }
1029                 if (!list_empty(&ci->i_flushing_item)) {
1030                         pr_info(" dropping dirty+flushing %s state for %p %lld\n",
1031                                 ceph_cap_string(ci->i_flushing_caps),
1032                                 inode, ceph_ino(inode));
1033                         ci->i_flushing_caps = 0;
1034                         list_del_init(&ci->i_flushing_item);
1035                         mdsc->num_cap_flushing--;
1036                         drop = 1;
1037                 }
1038                 if (drop && ci->i_wrbuffer_ref) {
1039                         pr_info(" dropping dirty data for %p %lld\n",
1040                                 inode, ceph_ino(inode));
1041                         ci->i_wrbuffer_ref = 0;
1042                         ci->i_wrbuffer_ref_head = 0;
1043                         drop++;
1044                 }
1045                 spin_unlock(&mdsc->cap_dirty_lock);
1046         }
1047         spin_unlock(&ci->i_ceph_lock);
1048         while (drop--)
1049                 iput(inode);
1050         return 0;
1051 }
1052 
1053 /*
1054  * caller must hold session s_mutex
1055  */
1056 static void remove_session_caps(struct ceph_mds_session *session)
1057 {
1058         dout("remove_session_caps on %p\n", session);
1059         iterate_session_caps(session, remove_session_caps_cb, NULL);
1060 
1061         spin_lock(&session->s_cap_lock);
1062         if (session->s_nr_caps > 0) {
1063                 struct super_block *sb = session->s_mdsc->fsc->sb;
1064                 struct inode *inode;
1065                 struct ceph_cap *cap, *prev = NULL;
1066                 struct ceph_vino vino;
1067                 /*
1068                  * iterate_session_caps() skips inodes that are being
1069                  * deleted, we need to wait until deletions are complete.
1070                  * __wait_on_freeing_inode() is designed for the job,
1071                  * but it is not exported, so use lookup inode function
1072                  * to access it.
1073                  */
1074                 while (!list_empty(&session->s_caps)) {
1075                         cap = list_entry(session->s_caps.next,
1076                                          struct ceph_cap, session_caps);
1077                         if (cap == prev)
1078                                 break;
1079                         prev = cap;
1080                         vino = cap->ci->i_vino;
1081                         spin_unlock(&session->s_cap_lock);
1082 
1083                         inode = ceph_find_inode(sb, vino);
1084                         iput(inode);
1085 
1086                         spin_lock(&session->s_cap_lock);
1087                 }
1088         }
1089         spin_unlock(&session->s_cap_lock);
1090 
1091         BUG_ON(session->s_nr_caps > 0);
1092         BUG_ON(!list_empty(&session->s_cap_flushing));
1093         cleanup_cap_releases(session);
1094 }
1095 
1096 /*
1097  * wake up any threads waiting on this session's caps.  if the cap is
1098  * old (didn't get renewed on the client reconnect), remove it now.
1099  *
1100  * caller must hold s_mutex.
1101  */
1102 static int wake_up_session_cb(struct inode *inode, struct ceph_cap *cap,
1103                               void *arg)
1104 {
1105         struct ceph_inode_info *ci = ceph_inode(inode);
1106 
1107         wake_up_all(&ci->i_cap_wq);
1108         if (arg) {
1109                 spin_lock(&ci->i_ceph_lock);
1110                 ci->i_wanted_max_size = 0;
1111                 ci->i_requested_max_size = 0;
1112                 spin_unlock(&ci->i_ceph_lock);
1113         }
1114         return 0;
1115 }
1116 
1117 static void wake_up_session_caps(struct ceph_mds_session *session,
1118                                  int reconnect)
1119 {
1120         dout("wake_up_session_caps %p mds%d\n", session, session->s_mds);
1121         iterate_session_caps(session, wake_up_session_cb,
1122                              (void *)(unsigned long)reconnect);
1123 }
1124 
1125 /*
1126  * Send periodic message to MDS renewing all currently held caps.  The
1127  * ack will reset the expiration for all caps from this session.
1128  *
1129  * caller holds s_mutex
1130  */
1131 static int send_renew_caps(struct ceph_mds_client *mdsc,
1132                            struct ceph_mds_session *session)
1133 {
1134         struct ceph_msg *msg;
1135         int state;
1136 
1137         if (time_after_eq(jiffies, session->s_cap_ttl) &&
1138             time_after_eq(session->s_cap_ttl, session->s_renew_requested))
1139                 pr_info("mds%d caps stale\n", session->s_mds);
1140         session->s_renew_requested = jiffies;
1141 
1142         /* do not try to renew caps until a recovering mds has reconnected
1143          * with its clients. */
1144         state = ceph_mdsmap_get_state(mdsc->mdsmap, session->s_mds);
1145         if (state < CEPH_MDS_STATE_RECONNECT) {
1146                 dout("send_renew_caps ignoring mds%d (%s)\n",
1147                      session->s_mds, ceph_mds_state_name(state));
1148                 return 0;
1149         }
1150 
1151         dout("send_renew_caps to mds%d (%s)\n", session->s_mds,
1152                 ceph_mds_state_name(state));
1153         msg = create_session_msg(CEPH_SESSION_REQUEST_RENEWCAPS,
1154                                  ++session->s_renew_seq);
1155         if (!msg)
1156                 return -ENOMEM;
1157         ceph_con_send(&session->s_con, msg);
1158         return 0;
1159 }
1160 
1161 static int send_flushmsg_ack(struct ceph_mds_client *mdsc,
1162                              struct ceph_mds_session *session, u64 seq)
1163 {
1164         struct ceph_msg *msg;
1165 
1166         dout("send_flushmsg_ack to mds%d (%s)s seq %lld\n",
1167              session->s_mds, session_state_name(session->s_state), seq);
1168         msg = create_session_msg(CEPH_SESSION_FLUSHMSG_ACK, seq);
1169         if (!msg)
1170                 return -ENOMEM;
1171         ceph_con_send(&session->s_con, msg);
1172         return 0;
1173 }
1174 
1175 
1176 /*
1177  * Note new cap ttl, and any transition from stale -> not stale (fresh?).
1178  *
1179  * Called under session->s_mutex
1180  */
1181 static void renewed_caps(struct ceph_mds_client *mdsc,
1182                          struct ceph_mds_session *session, int is_renew)
1183 {
1184         int was_stale;
1185         int wake = 0;
1186 
1187         spin_lock(&session->s_cap_lock);
1188         was_stale = is_renew && time_after_eq(jiffies, session->s_cap_ttl);
1189 
1190         session->s_cap_ttl = session->s_renew_requested +
1191                 mdsc->mdsmap->m_session_timeout*HZ;
1192 
1193         if (was_stale) {
1194                 if (time_before(jiffies, session->s_cap_ttl)) {
1195                         pr_info("mds%d caps renewed\n", session->s_mds);
1196                         wake = 1;
1197                 } else {
1198                         pr_info("mds%d caps still stale\n", session->s_mds);
1199                 }
1200         }
1201         dout("renewed_caps mds%d ttl now %lu, was %s, now %s\n",
1202              session->s_mds, session->s_cap_ttl, was_stale ? "stale" : "fresh",
1203              time_before(jiffies, session->s_cap_ttl) ? "stale" : "fresh");
1204         spin_unlock(&session->s_cap_lock);
1205 
1206         if (wake)
1207                 wake_up_session_caps(session, 0);
1208 }
1209 
1210 /*
1211  * send a session close request
1212  */
1213 static int request_close_session(struct ceph_mds_client *mdsc,
1214                                  struct ceph_mds_session *session)
1215 {
1216         struct ceph_msg *msg;
1217 
1218         dout("request_close_session mds%d state %s seq %lld\n",
1219              session->s_mds, session_state_name(session->s_state),
1220              session->s_seq);
1221         msg = create_session_msg(CEPH_SESSION_REQUEST_CLOSE, session->s_seq);
1222         if (!msg)
1223                 return -ENOMEM;
1224         ceph_con_send(&session->s_con, msg);
1225         return 0;
1226 }
1227 
1228 /*
1229  * Called with s_mutex held.
1230  */
1231 static int __close_session(struct ceph_mds_client *mdsc,
1232                          struct ceph_mds_session *session)
1233 {
1234         if (session->s_state >= CEPH_MDS_SESSION_CLOSING)
1235                 return 0;
1236         session->s_state = CEPH_MDS_SESSION_CLOSING;
1237         return request_close_session(mdsc, session);
1238 }
1239 
1240 /*
1241  * Trim old(er) caps.
1242  *
1243  * Because we can't cache an inode without one or more caps, we do
1244  * this indirectly: if a cap is unused, we prune its aliases, at which
1245  * point the inode will hopefully get dropped to.
1246  *
1247  * Yes, this is a bit sloppy.  Our only real goal here is to respond to
1248  * memory pressure from the MDS, though, so it needn't be perfect.
1249  */
1250 static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
1251 {
1252         struct ceph_mds_session *session = arg;
1253         struct ceph_inode_info *ci = ceph_inode(inode);
1254         int used, wanted, oissued, mine;
1255 
1256         if (session->s_trim_caps <= 0)
1257                 return -1;
1258 
1259         spin_lock(&ci->i_ceph_lock);
1260         mine = cap->issued | cap->implemented;
1261         used = __ceph_caps_used(ci);
1262         wanted = __ceph_caps_file_wanted(ci);
1263         oissued = __ceph_caps_issued_other(ci, cap);
1264 
1265         dout("trim_caps_cb %p cap %p mine %s oissued %s used %s wanted %s\n",
1266              inode, cap, ceph_cap_string(mine), ceph_cap_string(oissued),
1267              ceph_cap_string(used), ceph_cap_string(wanted));
1268         if (cap == ci->i_auth_cap) {
1269                 if (ci->i_dirty_caps | ci->i_flushing_caps)
1270                         goto out;
1271                 if ((used | wanted) & CEPH_CAP_ANY_WR)
1272                         goto out;
1273         }
1274         if ((used | wanted) & ~oissued & mine)
1275                 goto out;   /* we need these caps */
1276 
1277         session->s_trim_caps--;
1278         if (oissued) {
1279                 /* we aren't the only cap.. just remove us */
1280                 __ceph_remove_cap(cap, true);
1281         } else {
1282                 /* try to drop referring dentries */
1283                 spin_unlock(&ci->i_ceph_lock);
1284                 d_prune_aliases(inode);
1285                 dout("trim_caps_cb %p cap %p  pruned, count now %d\n",
1286                      inode, cap, atomic_read(&inode->i_count));
1287                 return 0;
1288         }
1289 
1290 out:
1291         spin_unlock(&ci->i_ceph_lock);
1292         return 0;
1293 }
1294 
1295 /*
1296  * Trim session cap count down to some max number.
1297  */
1298 static int trim_caps(struct ceph_mds_client *mdsc,
1299                      struct ceph_mds_session *session,
1300                      int max_caps)
1301 {
1302         int trim_caps = session->s_nr_caps - max_caps;
1303 
1304         dout("trim_caps mds%d start: %d / %d, trim %d\n",
1305              session->s_mds, session->s_nr_caps, max_caps, trim_caps);
1306         if (trim_caps > 0) {
1307                 session->s_trim_caps = trim_caps;
1308                 iterate_session_caps(session, trim_caps_cb, session);
1309                 dout("trim_caps mds%d done: %d / %d, trimmed %d\n",
1310                      session->s_mds, session->s_nr_caps, max_caps,
1311                         trim_caps - session->s_trim_caps);
1312                 session->s_trim_caps = 0;
1313         }
1314 
1315         ceph_add_cap_releases(mdsc, session);
1316         ceph_send_cap_releases(mdsc, session);
1317         return 0;
1318 }
1319 
1320 /*
1321  * Allocate cap_release messages.  If there is a partially full message
1322  * in the queue, try to allocate enough to cover it's remainder, so that
1323  * we can send it immediately.
1324  *
1325  * Called under s_mutex.
1326  */
1327 int ceph_add_cap_releases(struct ceph_mds_client *mdsc,
1328                           struct ceph_mds_session *session)
1329 {
1330         struct ceph_msg *msg, *partial = NULL;
1331         struct ceph_mds_cap_release *head;
1332         int err = -ENOMEM;
1333         int extra = mdsc->fsc->mount_options->cap_release_safety;
1334         int num;
1335 
1336         dout("add_cap_releases %p mds%d extra %d\n", session, session->s_mds,
1337              extra);
1338 
1339         spin_lock(&session->s_cap_lock);
1340 
1341         if (!list_empty(&session->s_cap_releases)) {
1342                 msg = list_first_entry(&session->s_cap_releases,
1343                                        struct ceph_msg,
1344                                  list_head);
1345                 head = msg->front.iov_base;
1346                 num = le32_to_cpu(head->num);
1347                 if (num) {
1348                         dout(" partial %p with (%d/%d)\n", msg, num,
1349                              (int)CEPH_CAPS_PER_RELEASE);
1350                         extra += CEPH_CAPS_PER_RELEASE - num;
1351                         partial = msg;
1352                 }
1353         }
1354         while (session->s_num_cap_releases < session->s_nr_caps + extra) {
1355                 spin_unlock(&session->s_cap_lock);
1356                 msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPRELEASE, PAGE_CACHE_SIZE,
1357                                    GFP_NOFS, false);
1358                 if (!msg)
1359                         goto out_unlocked;
1360                 dout("add_cap_releases %p msg %p now %d\n", session, msg,
1361                      (int)msg->front.iov_len);
1362                 head = msg->front.iov_base;
1363                 head->num = cpu_to_le32(0);
1364                 msg->front.iov_len = sizeof(*head);
1365                 spin_lock(&session->s_cap_lock);
1366                 list_add(&msg->list_head, &session->s_cap_releases);
1367                 session->s_num_cap_releases += CEPH_CAPS_PER_RELEASE;
1368         }
1369 
1370         if (partial) {
1371                 head = partial->front.iov_base;
1372                 num = le32_to_cpu(head->num);
1373                 dout(" queueing partial %p with %d/%d\n", partial, num,
1374                      (int)CEPH_CAPS_PER_RELEASE);
1375                 list_move_tail(&partial->list_head,
1376                                &session->s_cap_releases_done);
1377                 session->s_num_cap_releases -= CEPH_CAPS_PER_RELEASE - num;
1378         }
1379         err = 0;
1380         spin_unlock(&session->s_cap_lock);
1381 out_unlocked:
1382         return err;
1383 }
1384 
1385 /*
1386  * flush all dirty inode data to disk.
1387  *
1388  * returns true if we've flushed through want_flush_seq
1389  */
1390 static int check_cap_flush(struct ceph_mds_client *mdsc, u64 want_flush_seq)
1391 {
1392         int mds, ret = 1;
1393 
1394         dout("check_cap_flush want %lld\n", want_flush_seq);
1395         mutex_lock(&mdsc->mutex);
1396         for (mds = 0; ret && mds < mdsc->max_sessions; mds++) {
1397                 struct ceph_mds_session *session = mdsc->sessions[mds];
1398 
1399                 if (!session)
1400                         continue;
1401                 get_session(session);
1402                 mutex_unlock(&mdsc->mutex);
1403 
1404                 mutex_lock(&session->s_mutex);
1405                 if (!list_empty(&session->s_cap_flushing)) {
1406                         struct ceph_inode_info *ci =
1407                                 list_entry(session->s_cap_flushing.next,
1408                                            struct ceph_inode_info,
1409                                            i_flushing_item);
1410                         struct inode *inode = &ci->vfs_inode;
1411 
1412                         spin_lock(&ci->i_ceph_lock);
1413                         if (ci->i_cap_flush_seq <= want_flush_seq) {
1414                                 dout("check_cap_flush still flushing %p "
1415                                      "seq %lld <= %lld to mds%d\n", inode,
1416                                      ci->i_cap_flush_seq, want_flush_seq,
1417                                      session->s_mds);
1418                                 ret = 0;
1419                         }
1420                         spin_unlock(&ci->i_ceph_lock);
1421                 }
1422                 mutex_unlock(&session->s_mutex);
1423                 ceph_put_mds_session(session);
1424 
1425                 if (!ret)
1426                         return ret;
1427                 mutex_lock(&mdsc->mutex);
1428         }
1429 
1430         mutex_unlock(&mdsc->mutex);
1431         dout("check_cap_flush ok, flushed thru %lld\n", want_flush_seq);
1432         return ret;
1433 }
1434 
1435 /*
1436  * called under s_mutex
1437  */
1438 void ceph_send_cap_releases(struct ceph_mds_client *mdsc,
1439                             struct ceph_mds_session *session)
1440 {
1441         struct ceph_msg *msg;
1442 
1443         dout("send_cap_releases mds%d\n", session->s_mds);
1444         spin_lock(&session->s_cap_lock);
1445         while (!list_empty(&session->s_cap_releases_done)) {
1446                 msg = list_first_entry(&session->s_cap_releases_done,
1447                                  struct ceph_msg, list_head);
1448                 list_del_init(&msg->list_head);
1449                 spin_unlock(&session->s_cap_lock);
1450                 msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
1451                 dout("send_cap_releases mds%d %p\n", session->s_mds, msg);
1452                 ceph_con_send(&session->s_con, msg);
1453                 spin_lock(&session->s_cap_lock);
1454         }
1455         spin_unlock(&session->s_cap_lock);
1456 }
1457 
1458 static void discard_cap_releases(struct ceph_mds_client *mdsc,
1459                                  struct ceph_mds_session *session)
1460 {
1461         struct ceph_msg *msg;
1462         struct ceph_mds_cap_release *head;
1463         unsigned num;
1464 
1465         dout("discard_cap_releases mds%d\n", session->s_mds);
1466 
1467         if (!list_empty(&session->s_cap_releases)) {
1468                 /* zero out the in-progress message */
1469                 msg = list_first_entry(&session->s_cap_releases,
1470                                         struct ceph_msg, list_head);
1471                 head = msg->front.iov_base;
1472                 num = le32_to_cpu(head->num);
1473                 dout("discard_cap_releases mds%d %p %u\n",
1474                      session->s_mds, msg, num);
1475                 head->num = cpu_to_le32(0);
1476                 msg->front.iov_len = sizeof(*head);
1477                 session->s_num_cap_releases += num;
1478         }
1479 
1480         /* requeue completed messages */
1481         while (!list_empty(&session->s_cap_releases_done)) {
1482                 msg = list_first_entry(&session->s_cap_releases_done,
1483                                  struct ceph_msg, list_head);
1484                 list_del_init(&msg->list_head);
1485 
1486                 head = msg->front.iov_base;
1487                 num = le32_to_cpu(head->num);
1488                 dout("discard_cap_releases mds%d %p %u\n", session->s_mds, msg,
1489                      num);
1490                 session->s_num_cap_releases += num;
1491                 head->num = cpu_to_le32(0);
1492                 msg->front.iov_len = sizeof(*head);
1493                 list_add(&msg->list_head, &session->s_cap_releases);
1494         }
1495 }
1496 
1497 /*
1498  * requests
1499  */
1500 
1501 int ceph_alloc_readdir_reply_buffer(struct ceph_mds_request *req,
1502                                     struct inode *dir)
1503 {
1504         struct ceph_inode_info *ci = ceph_inode(dir);
1505         struct ceph_mds_reply_info_parsed *rinfo = &req->r_reply_info;
1506         struct ceph_mount_options *opt = req->r_mdsc->fsc->mount_options;
1507         size_t size = sizeof(*rinfo->dir_in) + sizeof(*rinfo->dir_dname_len) +
1508                       sizeof(*rinfo->dir_dname) + sizeof(*rinfo->dir_dlease);
1509         int order, num_entries;
1510 
1511         spin_lock(&ci->i_ceph_lock);
1512         num_entries = ci->i_files + ci->i_subdirs;
1513         spin_unlock(&ci->i_ceph_lock);
1514         num_entries = max(num_entries, 1);
1515         num_entries = min(num_entries, opt->max_readdir);
1516 
1517         order = get_order(size * num_entries);
1518         while (order >= 0) {
1519                 rinfo->dir_in = (void*)__get_free_pages(GFP_NOFS | __GFP_NOWARN,
1520                                                         order);
1521                 if (rinfo->dir_in)
1522                         break;
1523                 order--;
1524         }
1525         if (!rinfo->dir_in)
1526                 return -ENOMEM;
1527 
1528         num_entries = (PAGE_SIZE << order) / size;
1529         num_entries = min(num_entries, opt->max_readdir);
1530 
1531         rinfo->dir_buf_size = PAGE_SIZE << order;
1532         req->r_num_caps = num_entries + 1;
1533         req->r_args.readdir.max_entries = cpu_to_le32(num_entries);
1534         req->r_args.readdir.max_bytes = cpu_to_le32(opt->max_readdir_bytes);
1535         return 0;
1536 }
1537 
1538 /*
1539  * Create an mds request.
1540  */
1541 struct ceph_mds_request *
1542 ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode)
1543 {
1544         struct ceph_mds_request *req = kzalloc(sizeof(*req), GFP_NOFS);
1545 
1546         if (!req)
1547                 return ERR_PTR(-ENOMEM);
1548 
1549         mutex_init(&req->r_fill_mutex);
1550         req->r_mdsc = mdsc;
1551         req->r_started = jiffies;
1552         req->r_resend_mds = -1;
1553         INIT_LIST_HEAD(&req->r_unsafe_dir_item);
1554         req->r_fmode = -1;
1555         kref_init(&req->r_kref);
1556         INIT_LIST_HEAD(&req->r_wait);
1557         init_completion(&req->r_completion);
1558         init_completion(&req->r_safe_completion);
1559         INIT_LIST_HEAD(&req->r_unsafe_item);
1560 
1561         req->r_op = op;
1562         req->r_direct_mode = mode;
1563         return req;
1564 }
1565 
1566 /*
1567  * return oldest (lowest) request, tid in request tree, 0 if none.
1568  *
1569  * called under mdsc->mutex.
1570  */
1571 static struct ceph_mds_request *__get_oldest_req(struct ceph_mds_client *mdsc)
1572 {
1573         if (RB_EMPTY_ROOT(&mdsc->request_tree))
1574                 return NULL;
1575         return rb_entry(rb_first(&mdsc->request_tree),
1576                         struct ceph_mds_request, r_node);
1577 }
1578 
1579 static u64 __get_oldest_tid(struct ceph_mds_client *mdsc)
1580 {
1581         struct ceph_mds_request *req = __get_oldest_req(mdsc);
1582 
1583         if (req)
1584                 return req->r_tid;
1585         return 0;
1586 }
1587 
1588 /*
1589  * Build a dentry's path.  Allocate on heap; caller must kfree.  Based
1590  * on build_path_from_dentry in fs/cifs/dir.c.
1591  *
1592  * If @stop_on_nosnap, generate path relative to the first non-snapped
1593  * inode.
1594  *
1595  * Encode hidden .snap dirs as a double /, i.e.
1596  *   foo/.snap/bar -> foo//bar
1597  */
1598 char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *base,
1599                            int stop_on_nosnap)
1600 {
1601         struct dentry *temp;
1602         char *path;
1603         int len, pos;
1604         unsigned seq;
1605 
1606         if (dentry == NULL)
1607                 return ERR_PTR(-EINVAL);
1608 
1609 retry:
1610         len = 0;
1611         seq = read_seqbegin(&rename_lock);
1612         rcu_read_lock();
1613         for (temp = dentry; !IS_ROOT(temp);) {
1614                 struct inode *inode = temp->d_inode;
1615                 if (inode && ceph_snap(inode) == CEPH_SNAPDIR)
1616                         len++;  /* slash only */
1617                 else if (stop_on_nosnap && inode &&
1618                          ceph_snap(inode) == CEPH_NOSNAP)
1619                         break;
1620                 else
1621                         len += 1 + temp->d_name.len;
1622                 temp = temp->d_parent;
1623         }
1624         rcu_read_unlock();
1625         if (len)
1626                 len--;  /* no leading '/' */
1627 
1628         path = kmalloc(len+1, GFP_NOFS);
1629         if (path == NULL)
1630                 return ERR_PTR(-ENOMEM);
1631         pos = len;
1632         path[pos] = 0;  /* trailing null */
1633         rcu_read_lock();
1634         for (temp = dentry; !IS_ROOT(temp) && pos != 0; ) {
1635                 struct inode *inode;
1636 
1637                 spin_lock(&temp->d_lock);
1638                 inode = temp->d_inode;
1639                 if (inode && ceph_snap(inode) == CEPH_SNAPDIR) {
1640                         dout("build_path path+%d: %p SNAPDIR\n",
1641                              pos, temp);
1642                 } else if (stop_on_nosnap && inode &&
1643                            ceph_snap(inode) == CEPH_NOSNAP) {
1644                         spin_unlock(&temp->d_lock);
1645                         break;
1646                 } else {
1647                         pos -= temp->d_name.len;
1648                         if (pos < 0) {
1649                                 spin_unlock(&temp->d_lock);
1650                                 break;
1651                         }
1652                         strncpy(path + pos, temp->d_name.name,
1653                                 temp->d_name.len);
1654                 }
1655                 spin_unlock(&temp->d_lock);
1656                 if (pos)
1657                         path[--pos] = '/';
1658                 temp = temp->d_parent;
1659         }
1660         rcu_read_unlock();
1661         if (pos != 0 || read_seqretry(&rename_lock, seq)) {
1662                 pr_err("build_path did not end path lookup where "
1663                        "expected, namelen is %d, pos is %d\n", len, pos);
1664                 /* presumably this is only possible if racing with a
1665                    rename of one of the parent directories (we can not
1666                    lock the dentries above us to prevent this, but
1667                    retrying should be harmless) */
1668                 kfree(path);
1669                 goto retry;
1670         }
1671 
1672         *base = ceph_ino(temp->d_inode);
1673         *plen = len;
1674         dout("build_path on %p %d built %llx '%.*s'\n",
1675              dentry, d_count(dentry), *base, len, path);
1676         return path;
1677 }
1678 
1679 static int build_dentry_path(struct dentry *dentry,
1680                              const char **ppath, int *ppathlen, u64 *pino,
1681                              int *pfreepath)
1682 {
1683         char *path;
1684 
1685         if (ceph_snap(dentry->d_parent->d_inode) == CEPH_NOSNAP) {
1686                 *pino = ceph_ino(dentry->d_parent->d_inode);
1687                 *ppath = dentry->d_name.name;
1688                 *ppathlen = dentry->d_name.len;
1689                 return 0;
1690         }
1691         path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
1692         if (IS_ERR(path))
1693                 return PTR_ERR(path);
1694         *ppath = path;
1695         *pfreepath = 1;
1696         return 0;
1697 }
1698 
1699 static int build_inode_path(struct inode *inode,
1700                             const char **ppath, int *ppathlen, u64 *pino,
1701                             int *pfreepath)
1702 {
1703         struct dentry *dentry;
1704         char *path;
1705 
1706         if (ceph_snap(inode) == CEPH_NOSNAP) {
1707                 *pino = ceph_ino(inode);
1708                 *ppathlen = 0;
1709                 return 0;
1710         }
1711         dentry = d_find_alias(inode);
1712         path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
1713         dput(dentry);
1714         if (IS_ERR(path))
1715                 return PTR_ERR(path);
1716         *ppath = path;
1717         *pfreepath = 1;
1718         return 0;
1719 }
1720 
1721 /*
1722  * request arguments may be specified via an inode *, a dentry *, or
1723  * an explicit ino+path.
1724  */
1725 static int set_request_path_attr(struct inode *rinode, struct dentry *rdentry,
1726                                   const char *rpath, u64 rino,
1727                                   const char **ppath, int *pathlen,
1728                                   u64 *ino, int *freepath)
1729 {
1730         int r = 0;
1731 
1732         if (rinode) {
1733                 r = build_inode_path(rinode, ppath, pathlen, ino, freepath);
1734                 dout(" inode %p %llx.%llx\n", rinode, ceph_ino(rinode),
1735                      ceph_snap(rinode));
1736         } else if (rdentry) {
1737                 r = build_dentry_path(rdentry, ppath, pathlen, ino, freepath);
1738                 dout(" dentry %p %llx/%.*s\n", rdentry, *ino, *pathlen,
1739                      *ppath);
1740         } else if (rpath || rino) {
1741                 *ino = rino;
1742                 *ppath = rpath;
1743                 *pathlen = rpath ? strlen(rpath) : 0;
1744                 dout(" path %.*s\n", *pathlen, rpath);
1745         }
1746 
1747         return r;
1748 }
1749 
1750 /*
1751  * called under mdsc->mutex
1752  */
1753 static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
1754                                                struct ceph_mds_request *req,
1755                                                int mds)
1756 {
1757         struct ceph_msg *msg;
1758         struct ceph_mds_request_head *head;
1759         const char *path1 = NULL;
1760         const char *path2 = NULL;
1761         u64 ino1 = 0, ino2 = 0;
1762         int pathlen1 = 0, pathlen2 = 0;
1763         int freepath1 = 0, freepath2 = 0;
1764         int len;
1765         u16 releases;
1766         void *p, *end;
1767         int ret;
1768 
1769         ret = set_request_path_attr(req->r_inode, req->r_dentry,
1770                               req->r_path1, req->r_ino1.ino,
1771                               &path1, &pathlen1, &ino1, &freepath1);
1772         if (ret < 0) {
1773                 msg = ERR_PTR(ret);
1774                 goto out;
1775         }
1776 
1777         ret = set_request_path_attr(NULL, req->r_old_dentry,
1778                               req->r_path2, req->r_ino2.ino,
1779                               &path2, &pathlen2, &ino2, &freepath2);
1780         if (ret < 0) {
1781                 msg = ERR_PTR(ret);
1782                 goto out_free1;
1783         }
1784 
1785         len = sizeof(*head) +
1786                 pathlen1 + pathlen2 + 2*(1 + sizeof(u32) + sizeof(u64));
1787 
1788         /* calculate (max) length for cap releases */
1789         len += sizeof(struct ceph_mds_request_release) *
1790                 (!!req->r_inode_drop + !!req->r_dentry_drop +
1791                  !!req->r_old_inode_drop + !!req->r_old_dentry_drop);
1792         if (req->r_dentry_drop)
1793                 len += req->r_dentry->d_name.len;
1794         if (req->r_old_dentry_drop)
1795                 len += req->r_old_dentry->d_name.len;
1796 
1797         msg = ceph_msg_new(CEPH_MSG_CLIENT_REQUEST, len, GFP_NOFS, false);
1798         if (!msg) {
1799                 msg = ERR_PTR(-ENOMEM);
1800                 goto out_free2;
1801         }
1802 
1803         msg->hdr.tid = cpu_to_le64(req->r_tid);
1804 
1805         head = msg->front.iov_base;
1806         p = msg->front.iov_base + sizeof(*head);
1807         end = msg->front.iov_base + msg->front.iov_len;
1808 
1809         head->mdsmap_epoch = cpu_to_le32(mdsc->mdsmap->m_epoch);
1810         head->op = cpu_to_le32(req->r_op);
1811         head->caller_uid = cpu_to_le32(from_kuid(&init_user_ns, req->r_uid));
1812         head->caller_gid = cpu_to_le32(from_kgid(&init_user_ns, req->r_gid));
1813         head->args = req->r_args;
1814 
1815         ceph_encode_filepath(&p, end, ino1, path1);
1816         ceph_encode_filepath(&p, end, ino2, path2);
1817 
1818         /* make note of release offset, in case we need to replay */
1819         req->r_request_release_offset = p - msg->front.iov_base;
1820 
1821         /* cap releases */
1822         releases = 0;
1823         if (req->r_inode_drop)
1824                 releases += ceph_encode_inode_release(&p,
1825                       req->r_inode ? req->r_inode : req->r_dentry->d_inode,
1826                       mds, req->r_inode_drop, req->r_inode_unless, 0);
1827         if (req->r_dentry_drop)
1828                 releases += ceph_encode_dentry_release(&p, req->r_dentry,
1829                        mds, req->r_dentry_drop, req->r_dentry_unless);
1830         if (req->r_old_dentry_drop)
1831                 releases += ceph_encode_dentry_release(&p, req->r_old_dentry,
1832                        mds, req->r_old_dentry_drop, req->r_old_dentry_unless);
1833         if (req->r_old_inode_drop)
1834                 releases += ceph_encode_inode_release(&p,
1835                       req->r_old_dentry->d_inode,
1836                       mds, req->r_old_inode_drop, req->r_old_inode_unless, 0);
1837         head->num_releases = cpu_to_le16(releases);
1838 
1839         BUG_ON(p > end);
1840         msg->front.iov_len = p - msg->front.iov_base;
1841         msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
1842 
1843         if (req->r_data_len) {
1844                 /* outbound data set only by ceph_sync_setxattr() */
1845                 BUG_ON(!req->r_pages);
1846                 ceph_msg_data_add_pages(msg, req->r_pages, req->r_data_len, 0);
1847         }
1848 
1849         msg->hdr.data_len = cpu_to_le32(req->r_data_len);
1850         msg->hdr.data_off = cpu_to_le16(0);
1851 
1852 out_free2:
1853         if (freepath2)
1854                 kfree((char *)path2);
1855 out_free1:
1856         if (freepath1)
1857                 kfree((char *)path1);
1858 out:
1859         return msg;
1860 }
1861 
1862 /*
1863  * called under mdsc->mutex if error, under no mutex if
1864  * success.
1865  */
1866 static void complete_request(struct ceph_mds_client *mdsc,
1867                              struct ceph_mds_request *req)
1868 {
1869         if (req->r_callback)
1870                 req->r_callback(mdsc, req);
1871         else
1872                 complete_all(&req->r_completion);
1873 }
1874 
1875 /*
1876  * called under mdsc->mutex
1877  */
1878 static int __prepare_send_request(struct ceph_mds_client *mdsc,
1879                                   struct ceph_mds_request *req,
1880                                   int mds)
1881 {
1882         struct ceph_mds_request_head *rhead;
1883         struct ceph_msg *msg;
1884         int flags = 0;
1885 
1886         req->r_attempts++;
1887         if (req->r_inode) {
1888                 struct ceph_cap *cap =
1889                         ceph_get_cap_for_mds(ceph_inode(req->r_inode), mds);
1890 
1891                 if (cap)
1892                         req->r_sent_on_mseq = cap->mseq;
1893                 else
1894                         req->r_sent_on_mseq = -1;
1895         }
1896         dout("prepare_send_request %p tid %lld %s (attempt %d)\n", req,
1897              req->r_tid, ceph_mds_op_name(req->r_op), req->r_attempts);
1898 
1899         if (req->r_got_unsafe) {
1900                 /*
1901                  * Replay.  Do not regenerate message (and rebuild
1902                  * paths, etc.); just use the original message.
1903                  * Rebuilding paths will break for renames because
1904                  * d_move mangles the src name.
1905                  */
1906                 msg = req->r_request;
1907                 rhead = msg->front.iov_base;
1908 
1909                 flags = le32_to_cpu(rhead->flags);
1910                 flags |= CEPH_MDS_FLAG_REPLAY;
1911                 rhead->flags = cpu_to_le32(flags);
1912 
1913                 if (req->r_target_inode)
1914                         rhead->ino = cpu_to_le64(ceph_ino(req->r_target_inode));
1915 
1916                 rhead->num_retry = req->r_attempts - 1;
1917 
1918                 /* remove cap/dentry releases from message */
1919                 rhead->num_releases = 0;
1920                 msg->hdr.front_len = cpu_to_le32(req->r_request_release_offset);
1921                 msg->front.iov_len = req->r_request_release_offset;
1922                 return 0;
1923         }
1924 
1925         if (req->r_request) {
1926                 ceph_msg_put(req->r_request);
1927                 req->r_request = NULL;
1928         }
1929         msg = create_request_message(mdsc, req, mds);
1930         if (IS_ERR(msg)) {
1931                 req->r_err = PTR_ERR(msg);
1932                 complete_request(mdsc, req);
1933                 return PTR_ERR(msg);
1934         }
1935         req->r_request = msg;
1936 
1937         rhead = msg->front.iov_base;
1938         rhead->oldest_client_tid = cpu_to_le64(__get_oldest_tid(mdsc));
1939         if (req->r_got_unsafe)
1940                 flags |= CEPH_MDS_FLAG_REPLAY;
1941         if (req->r_locked_dir)
1942                 flags |= CEPH_MDS_FLAG_WANT_DENTRY;
1943         rhead->flags = cpu_to_le32(flags);
1944         rhead->num_fwd = req->r_num_fwd;
1945         rhead->num_retry = req->r_attempts - 1;
1946         rhead->ino = 0;
1947 
1948         dout(" r_locked_dir = %p\n", req->r_locked_dir);
1949         return 0;
1950 }
1951 
1952 /*
1953  * send request, or put it on the appropriate wait list.
1954  */
1955 static int __do_request(struct ceph_mds_client *mdsc,
1956                         struct ceph_mds_request *req)
1957 {
1958         struct ceph_mds_session *session = NULL;
1959         int mds = -1;
1960         int err = -EAGAIN;
1961 
1962         if (req->r_err || req->r_got_result) {
1963                 if (req->r_aborted)
1964                         __unregister_request(mdsc, req);
1965                 goto out;
1966         }
1967 
1968         if (req->r_timeout &&
1969             time_after_eq(jiffies, req->r_started + req->r_timeout)) {
1970                 dout("do_request timed out\n");
1971                 err = -EIO;
1972                 goto finish;
1973         }
1974 
1975         put_request_session(req);
1976 
1977         mds = __choose_mds(mdsc, req);
1978         if (mds < 0 ||
1979             ceph_mdsmap_get_state(mdsc->mdsmap, mds) < CEPH_MDS_STATE_ACTIVE) {
1980                 dout("do_request no mds or not active, waiting for map\n");
1981                 list_add(&req->r_wait, &mdsc->waiting_for_map);
1982                 goto out;
1983         }
1984 
1985         /* get, open session */
1986         session = __ceph_lookup_mds_session(mdsc, mds);
1987         if (!session) {
1988                 session = register_session(mdsc, mds);
1989                 if (IS_ERR(session)) {
1990                         err = PTR_ERR(session);
1991                         goto finish;
1992                 }
1993         }
1994         req->r_session = get_session(session);
1995 
1996         dout("do_request mds%d session %p state %s\n", mds, session,
1997              session_state_name(session->s_state));
1998         if (session->s_state != CEPH_MDS_SESSION_OPEN &&
1999             session->s_state != CEPH_MDS_SESSION_HUNG) {
2000                 if (session->s_state == CEPH_MDS_SESSION_NEW ||
2001                     session->s_state == CEPH_MDS_SESSION_CLOSING)
2002                         __open_session(mdsc, session);
2003                 list_add(&req->r_wait, &session->s_waiting);
2004                 goto out_session;
2005         }
2006 
2007         /* send request */
2008         req->r_resend_mds = -1;   /* forget any previous mds hint */
2009 
2010         if (req->r_request_started == 0)   /* note request start time */
2011                 req->r_request_started = jiffies;
2012 
2013         err = __prepare_send_request(mdsc, req, mds);
2014         if (!err) {
2015                 ceph_msg_get(req->r_request);
2016                 ceph_con_send(&session->s_con, req->r_request);
2017         }
2018 
2019 out_session:
2020         ceph_put_mds_session(session);
2021 out:
2022         return err;
2023 
2024 finish:
2025         req->r_err = err;
2026         complete_request(mdsc, req);
2027         goto out;
2028 }
2029 
2030 /*
2031  * called under mdsc->mutex
2032  */
2033 static void __wake_requests(struct ceph_mds_client *mdsc,
2034                             struct list_head *head)
2035 {
2036         struct ceph_mds_request *req;
2037         LIST_HEAD(tmp_list);
2038 
2039         list_splice_init(head, &tmp_list);
2040 
2041         while (!list_empty(&tmp_list)) {
2042                 req = list_entry(tmp_list.next,
2043                                  struct ceph_mds_request, r_wait);
2044                 list_del_init(&req->r_wait);
2045                 dout(" wake request %p tid %llu\n", req, req->r_tid);
2046                 __do_request(mdsc, req);
2047         }
2048 }
2049 
2050 /*
2051  * Wake up threads with requests pending for @mds, so that they can
2052  * resubmit their requests to a possibly different mds.
2053  */
2054 static void kick_requests(struct ceph_mds_client *mdsc, int mds)
2055 {
2056         struct ceph_mds_request *req;
2057         struct rb_node *p;
2058 
2059         dout("kick_requests mds%d\n", mds);
2060         for (p = rb_first(&mdsc->request_tree); p; p = rb_next(p)) {
2061                 req = rb_entry(p, struct ceph_mds_request, r_node);
2062                 if (req->r_got_unsafe)
2063                         continue;
2064                 if (req->r_session &&
2065                     req->r_session->s_mds == mds) {
2066                         dout(" kicking tid %llu\n", req->r_tid);
2067                         __do_request(mdsc, req);
2068                 }
2069         }
2070 }
2071 
2072 void ceph_mdsc_submit_request(struct ceph_mds_client *mdsc,
2073                               struct ceph_mds_request *req)
2074 {
2075         dout("submit_request on %p\n", req);
2076         mutex_lock(&mdsc->mutex);
2077         __register_request(mdsc, req, NULL);
2078         __do_request(mdsc, req);
2079         mutex_unlock(&mdsc->mutex);
2080 }
2081 
2082 /*
2083  * Synchrously perform an mds request.  Take care of all of the
2084  * session setup, forwarding, retry details.
2085  */
2086 int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
2087                          struct inode *dir,
2088                          struct ceph_mds_request *req)
2089 {
2090         int err;
2091 
2092         dout("do_request on %p\n", req);
2093 
2094         /* take CAP_PIN refs for r_inode, r_locked_dir, r_old_dentry */
2095         if (req->r_inode)
2096                 ceph_get_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
2097         if (req->r_locked_dir)
2098                 ceph_get_cap_refs(ceph_inode(req->r_locked_dir), CEPH_CAP_PIN);
2099         if (req->r_old_dentry_dir)
2100                 ceph_get_cap_refs(ceph_inode(req->r_old_dentry_dir),
2101                                   CEPH_CAP_PIN);
2102 
2103         /* issue */
2104         mutex_lock(&mdsc->mutex);
2105         __register_request(mdsc, req, dir);
2106         __do_request(mdsc, req);
2107 
2108         if (req->r_err) {
2109                 err = req->r_err;
2110                 __unregister_request(mdsc, req);
2111                 dout("do_request early error %d\n", err);
2112                 goto out;
2113         }
2114 
2115         /* wait */
2116         mutex_unlock(&mdsc->mutex);
2117         dout("do_request waiting\n");
2118         if (req->r_timeout) {
2119                 err = (long)wait_for_completion_killable_timeout(
2120                         &req->r_completion, req->r_timeout);
2121                 if (err == 0)
2122                         err = -EIO;
2123         } else {
2124                 err = wait_for_completion_killable(&req->r_completion);
2125         }
2126         dout("do_request waited, got %d\n", err);
2127         mutex_lock(&mdsc->mutex);
2128 
2129         /* only abort if we didn't race with a real reply */
2130         if (req->r_got_result) {
2131                 err = le32_to_cpu(req->r_reply_info.head->result);
2132         } else if (err < 0) {
2133                 dout("aborted request %lld with %d\n", req->r_tid, err);
2134 
2135                 /*
2136                  * ensure we aren't running concurrently with
2137                  * ceph_fill_trace or ceph_readdir_prepopulate, which
2138                  * rely on locks (dir mutex) held by our caller.
2139                  */
2140                 mutex_lock(&req->r_fill_mutex);
2141                 req->r_err = err;
2142                 req->r_aborted = true;
2143                 mutex_unlock(&req->r_fill_mutex);
2144 
2145                 if (req->r_locked_dir &&
2146                     (req->r_op & CEPH_MDS_OP_WRITE))
2147                         ceph_invalidate_dir_request(req);
2148         } else {
2149                 err = req->r_err;
2150         }
2151 
2152 out:
2153         mutex_unlock(&mdsc->mutex);
2154         dout("do_request %p done, result %d\n", req, err);
2155         return err;
2156 }
2157 
2158 /*
2159  * Invalidate dir's completeness, dentry lease state on an aborted MDS
2160  * namespace request.
2161  */
2162 void ceph_invalidate_dir_request(struct ceph_mds_request *req)
2163 {
2164         struct inode *inode = req->r_locked_dir;
2165 
2166         dout("invalidate_dir_request %p (complete, lease(s))\n", inode);
2167 
2168         ceph_dir_clear_complete(inode);
2169         if (req->r_dentry)
2170                 ceph_invalidate_dentry_lease(req->r_dentry);
2171         if (req->r_old_dentry)
2172                 ceph_invalidate_dentry_lease(req->r_old_dentry);
2173 }
2174 
2175 /*
2176  * Handle mds reply.
2177  *
2178  * We take the session mutex and parse and process the reply immediately.
2179  * This preserves the logical ordering of replies, capabilities, etc., sent
2180  * by the MDS as they are applied to our local cache.
2181  */
2182 static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
2183 {
2184         struct ceph_mds_client *mdsc = session->s_mdsc;
2185         struct ceph_mds_request *req;
2186         struct ceph_mds_reply_head *head = msg->front.iov_base;
2187         struct ceph_mds_reply_info_parsed *rinfo;  /* parsed reply info */
2188         u64 tid;
2189         int err, result;
2190         int mds = session->s_mds;
2191 
2192         if (msg->front.iov_len < sizeof(*head)) {
2193                 pr_err("mdsc_handle_reply got corrupt (short) reply\n");
2194                 ceph_msg_dump(msg);
2195                 return;
2196         }
2197 
2198         /* get request, session */
2199         tid = le64_to_cpu(msg->hdr.tid);
2200         mutex_lock(&mdsc->mutex);
2201         req = __lookup_request(mdsc, tid);
2202         if (!req) {
2203                 dout("handle_reply on unknown tid %llu\n", tid);
2204                 mutex_unlock(&mdsc->mutex);
2205                 return;
2206         }
2207         dout("handle_reply %p\n", req);
2208 
2209         /* correct session? */
2210         if (req->r_session != session) {
2211                 pr_err("mdsc_handle_reply got %llu on session mds%d"
2212                        " not mds%d\n", tid, session->s_mds,
2213                        req->r_session ? req->r_session->s_mds : -1);
2214                 mutex_unlock(&mdsc->mutex);
2215                 goto out;
2216         }
2217 
2218         /* dup? */
2219         if ((req->r_got_unsafe && !head->safe) ||
2220             (req->r_got_safe && head->safe)) {
2221                 pr_warning("got a dup %s reply on %llu from mds%d\n",
2222                            head->safe ? "safe" : "unsafe", tid, mds);
2223                 mutex_unlock(&mdsc->mutex);
2224                 goto out;
2225         }
2226         if (req->r_got_safe && !head->safe) {
2227                 pr_warning("got unsafe after safe on %llu from mds%d\n",
2228                            tid, mds);
2229                 mutex_unlock(&mdsc->mutex);
2230                 goto out;
2231         }
2232 
2233         result = le32_to_cpu(head->result);
2234 
2235         /*
2236          * Handle an ESTALE
2237          * if we're not talking to the authority, send to them
2238          * if the authority has changed while we weren't looking,
2239          * send to new authority
2240          * Otherwise we just have to return an ESTALE
2241          */
2242         if (result == -ESTALE) {
2243                 dout("got ESTALE on request %llu", req->r_tid);
2244                 if (req->r_direct_mode != USE_AUTH_MDS) {
2245                         dout("not using auth, setting for that now");
2246                         req->r_direct_mode = USE_AUTH_MDS;
2247                         __do_request(mdsc, req);
2248                         mutex_unlock(&mdsc->mutex);
2249                         goto out;
2250                 } else  {
2251                         int mds = __choose_mds(mdsc, req);
2252                         if (mds >= 0 && mds != req->r_session->s_mds) {
2253                                 dout("but auth changed, so resending");
2254                                 __do_request(mdsc, req);
2255                                 mutex_unlock(&mdsc->mutex);
2256                                 goto out;
2257                         }
2258                 }
2259                 dout("have to return ESTALE on request %llu", req->r_tid);
2260         }
2261 
2262 
2263         if (head->safe) {
2264                 req->r_got_safe = true;
2265                 __unregister_request(mdsc, req);
2266 
2267                 if (req->r_got_unsafe) {
2268                         /*
2269                          * We already handled the unsafe response, now do the
2270                          * cleanup.  No need to examine the response; the MDS
2271                          * doesn't include any result info in the safe
2272                          * response.  And even if it did, there is nothing
2273                          * useful we could do with a revised return value.
2274                          */
2275                         dout("got safe reply %llu, mds%d\n", tid, mds);
2276                         list_del_init(&req->r_unsafe_item);
2277 
2278                         /* last unsafe request during umount? */
2279                         if (mdsc->stopping && !__get_oldest_req(mdsc))
2280                                 complete_all(&mdsc->safe_umount_waiters);
2281                         mutex_unlock(&mdsc->mutex);
2282                         goto out;
2283                 }
2284         } else {
2285                 req->r_got_unsafe = true;
2286                 list_add_tail(&req->r_unsafe_item, &req->r_session->s_unsafe);
2287         }
2288 
2289         dout("handle_reply tid %lld result %d\n", tid, result);
2290         rinfo = &req->r_reply_info;
2291         err = parse_reply_info(msg, rinfo, session->s_con.peer_features);
2292         mutex_unlock(&mdsc->mutex);
2293 
2294         mutex_lock(&session->s_mutex);
2295         if (err < 0) {
2296                 pr_err("mdsc_handle_reply got corrupt reply mds%d(tid:%lld)\n", mds, tid);
2297                 ceph_msg_dump(msg);
2298                 goto out_err;
2299         }
2300 
2301         /* snap trace */
2302         if (rinfo->snapblob_len) {
2303                 down_write(&mdsc->snap_rwsem);
2304                 ceph_update_snap_trace(mdsc, rinfo->snapblob,
2305                                rinfo->snapblob + rinfo->snapblob_len,
2306                                le32_to_cpu(head->op) == CEPH_MDS_OP_RMSNAP);
2307                 downgrade_write(&mdsc->snap_rwsem);
2308         } else {
2309                 down_read(&mdsc->snap_rwsem);
2310         }
2311 
2312         /* insert trace into our cache */
2313         mutex_lock(&req->r_fill_mutex);
2314         err = ceph_fill_trace(mdsc->fsc->sb, req, req->r_session);
2315         if (err == 0) {
2316                 if (result == 0 && (req->r_op == CEPH_MDS_OP_READDIR ||
2317                                     req->r_op == CEPH_MDS_OP_LSSNAP))
2318                         ceph_readdir_prepopulate(req, req->r_session);
2319                 ceph_unreserve_caps(mdsc, &req->r_caps_reservation);
2320         }
2321         mutex_unlock(&req->r_fill_mutex);
2322 
2323         up_read(&mdsc->snap_rwsem);
2324 out_err:
2325         mutex_lock(&mdsc->mutex);
2326         if (!req->r_aborted) {
2327                 if (err) {
2328                         req->r_err = err;
2329                 } else {
2330                         req->r_reply = msg;
2331                         ceph_msg_get(msg);
2332                         req->r_got_result = true;
2333                 }
2334         } else {
2335                 dout("reply arrived after request %lld was aborted\n", tid);
2336         }
2337         mutex_unlock(&mdsc->mutex);
2338 
2339         ceph_add_cap_releases(mdsc, req->r_session);
2340         mutex_unlock(&session->s_mutex);
2341 
2342         /* kick calling process */
2343         complete_request(mdsc, req);
2344 out:
2345         ceph_mdsc_put_request(req);
2346         return;
2347 }
2348 
2349 
2350 
2351 /*
2352  * handle mds notification that our request has been forwarded.
2353  */
2354 static void handle_forward(struct ceph_mds_client *mdsc,
2355                            struct ceph_mds_session *session,
2356                            struct ceph_msg *msg)
2357 {
2358         struct ceph_mds_request *req;
2359         u64 tid = le64_to_cpu(msg->hdr.tid);
2360         u32 next_mds;
2361         u32 fwd_seq;
2362         int err = -EINVAL;
2363         void *p = msg->front.iov_base;
2364         void *end = p + msg->front.iov_len;
2365 
2366         ceph_decode_need(&p, end, 2*sizeof(u32), bad);
2367         next_mds = ceph_decode_32(&p);
2368         fwd_seq = ceph_decode_32(&p);
2369 
2370         mutex_lock(&mdsc->mutex);
2371         req = __lookup_request(mdsc, tid);
2372         if (!req) {
2373                 dout("forward tid %llu to mds%d - req dne\n", tid, next_mds);
2374                 goto out;  /* dup reply? */
2375         }
2376 
2377         if (req->r_aborted) {
2378                 dout("forward tid %llu aborted, unregistering\n", tid);
2379                 __unregister_request(mdsc, req);
2380         } else if (fwd_seq <= req->r_num_fwd) {
2381                 dout("forward tid %llu to mds%d - old seq %d <= %d\n",
2382                      tid, next_mds, req->r_num_fwd, fwd_seq);
2383         } else {
2384                 /* resend. forward race not possible; mds would drop */
2385                 dout("forward tid %llu to mds%d (we resend)\n", tid, next_mds);
2386                 BUG_ON(req->r_err);
2387                 BUG_ON(req->r_got_result);
2388                 req->r_num_fwd = fwd_seq;
2389                 req->r_resend_mds = next_mds;
2390                 put_request_session(req);
2391                 __do_request(mdsc, req);
2392         }
2393         ceph_mdsc_put_request(req);
2394 out:
2395         mutex_unlock(&mdsc->mutex);
2396         return;
2397 
2398 bad:
2399         pr_err("mdsc_handle_forward decode error err=%d\n", err);
2400 }
2401 
2402 /*
2403  * handle a mds session control message
2404  */
2405 static void handle_session(struct ceph_mds_session *session,
2406                            struct ceph_msg *msg)
2407 {
2408         struct ceph_mds_client *mdsc = session->s_mdsc;
2409         u32 op;
2410         u64 seq;
2411         int mds = session->s_mds;
2412         struct ceph_mds_session_head *h = msg->front.iov_base;
2413         int wake = 0;
2414 
2415         /* decode */
2416         if (msg->front.iov_len != sizeof(*h))
2417                 goto bad;
2418         op = le32_to_cpu(h->op);
2419         seq = le64_to_cpu(h->seq);
2420 
2421         mutex_lock(&mdsc->mutex);
2422         if (op == CEPH_SESSION_CLOSE)
2423                 __unregister_session(mdsc, session);
2424         /* FIXME: this ttl calculation is generous */
2425         session->s_ttl = jiffies + HZ*mdsc->mdsmap->m_session_autoclose;
2426         mutex_unlock(&mdsc->mutex);
2427 
2428         mutex_lock(&session->s_mutex);
2429 
2430         dout("handle_session mds%d %s %p state %s seq %llu\n",
2431              mds, ceph_session_op_name(op), session,
2432              session_state_name(session->s_state), seq);
2433 
2434         if (session->s_state == CEPH_MDS_SESSION_HUNG) {
2435                 session->s_state = CEPH_MDS_SESSION_OPEN;
2436                 pr_info("mds%d came back\n", session->s_mds);
2437         }
2438 
2439         switch (op) {
2440         case CEPH_SESSION_OPEN:
2441                 if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
2442                         pr_info("mds%d reconnect success\n", session->s_mds);
2443                 session->s_state = CEPH_MDS_SESSION_OPEN;
2444                 renewed_caps(mdsc, session, 0);
2445                 wake = 1;
2446                 if (mdsc->stopping)
2447                         __close_session(mdsc, session);
2448                 break;
2449 
2450         case CEPH_SESSION_RENEWCAPS:
2451                 if (session->s_renew_seq == seq)
2452                         renewed_caps(mdsc, session, 1);
2453                 break;
2454 
2455         case CEPH_SESSION_CLOSE:
2456                 if (session->s_state == CEPH_MDS_SESSION_RECONNECTING)
2457                         pr_info("mds%d reconnect denied\n", session->s_mds);
2458                 remove_session_caps(session);
2459                 wake = 1; /* for good measure */
2460                 wake_up_all(&mdsc->session_close_wq);
2461                 kick_requests(mdsc, mds);
2462                 break;
2463 
2464         case CEPH_SESSION_STALE:
2465                 pr_info("mds%d caps went stale, renewing\n",
2466                         session->s_mds);
2467                 spin_lock(&session->s_gen_ttl_lock);
2468                 session->s_cap_gen++;
2469                 session->s_cap_ttl = jiffies - 1;
2470                 spin_unlock(&session->s_gen_ttl_lock);
2471                 send_renew_caps(mdsc, session);
2472                 break;
2473 
2474         case CEPH_SESSION_RECALL_STATE:
2475                 trim_caps(mdsc, session, le32_to_cpu(h->max_caps));
2476                 break;
2477 
2478         case CEPH_SESSION_FLUSHMSG:
2479                 send_flushmsg_ack(mdsc, session, seq);
2480                 break;
2481 
2482         default:
2483                 pr_err("mdsc_handle_session bad op %d mds%d\n", op, mds);
2484                 WARN_ON(1);
2485         }
2486 
2487         mutex_unlock(&session->s_mutex);
2488         if (wake) {
2489                 mutex_lock(&mdsc->mutex);
2490                 __wake_requests(mdsc, &session->s_waiting);
2491                 mutex_unlock(&mdsc->mutex);
2492         }
2493         return;
2494 
2495 bad:
2496         pr_err("mdsc_handle_session corrupt message mds%d len %d\n", mds,
2497                (int)msg->front.iov_len);
2498         ceph_msg_dump(msg);
2499         return;
2500 }
2501 
2502 
2503 /*
2504  * called under session->mutex.
2505  */
2506 static void replay_unsafe_requests(struct ceph_mds_client *mdsc,
2507                                    struct ceph_mds_session *session)
2508 {
2509         struct ceph_mds_request *req, *nreq;
2510         int err;
2511 
2512         dout("replay_unsafe_requests mds%d\n", session->s_mds);
2513 
2514         mutex_lock(&mdsc->mutex);
2515         list_for_each_entry_safe(req, nreq, &session->s_unsafe, r_unsafe_item) {
2516                 err = __prepare_send_request(mdsc, req, session->s_mds);
2517                 if (!err) {
2518                         ceph_msg_get(req->r_request);
2519                         ceph_con_send(&session->s_con, req->r_request);
2520                 }
2521         }
2522         mutex_unlock(&mdsc->mutex);
2523 }
2524 
2525 /*
2526  * Encode information about a cap for a reconnect with the MDS.
2527  */
2528 static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap,
2529                           void *arg)
2530 {
2531         union {
2532                 struct ceph_mds_cap_reconnect v2;
2533                 struct ceph_mds_cap_reconnect_v1 v1;
2534         } rec;
2535         size_t reclen;
2536         struct ceph_inode_info *ci;
2537         struct ceph_reconnect_state *recon_state = arg;
2538         struct ceph_pagelist *pagelist = recon_state->pagelist;
2539         char *path;
2540         int pathlen, err;
2541         u64 pathbase;
2542         struct dentry *dentry;
2543 
2544         ci = cap->ci;
2545 
2546         dout(" adding %p ino %llx.%llx cap %p %lld %s\n",
2547              inode, ceph_vinop(inode), cap, cap->cap_id,
2548              ceph_cap_string(cap->issued));
2549         err = ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
2550         if (err)
2551                 return err;
2552 
2553         dentry = d_find_alias(inode);
2554         if (dentry) {
2555                 path = ceph_mdsc_build_path(dentry, &pathlen, &pathbase, 0);
2556                 if (IS_ERR(path)) {
2557                         err = PTR_ERR(path);
2558                         goto out_dput;
2559                 }
2560         } else {
2561                 path = NULL;
2562                 pathlen = 0;
2563         }
2564         err = ceph_pagelist_encode_string(pagelist, path, pathlen);
2565         if (err)
2566                 goto out_free;
2567 
2568         spin_lock(&ci->i_ceph_lock);
2569         cap->seq = 0;        /* reset cap seq */
2570         cap->issue_seq = 0;  /* and issue_seq */
2571         cap->mseq = 0;       /* and migrate_seq */
2572         cap->cap_gen = cap->session->s_cap_gen;
2573 
2574         if (recon_state->flock) {
2575                 rec.v2.cap_id = cpu_to_le64(cap->cap_id);
2576                 rec.v2.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
2577                 rec.v2.issued = cpu_to_le32(cap->issued);
2578                 rec.v2.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
2579                 rec.v2.pathbase = cpu_to_le64(pathbase);
2580                 rec.v2.flock_len = 0;
2581                 reclen = sizeof(rec.v2);
2582         } else {
2583                 rec.v1.cap_id = cpu_to_le64(cap->cap_id);
2584                 rec.v1.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
2585                 rec.v1.issued = cpu_to_le32(cap->issued);
2586                 rec.v1.size = cpu_to_le64(inode->i_size);
2587                 ceph_encode_timespec(&rec.v1.mtime, &inode->i_mtime);
2588                 ceph_encode_timespec(&rec.v1.atime, &inode->i_atime);
2589                 rec.v1.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
2590                 rec.v1.pathbase = cpu_to_le64(pathbase);
2591                 reclen = sizeof(rec.v1);
2592         }
2593         spin_unlock(&ci->i_ceph_lock);
2594 
2595         if (recon_state->flock) {
2596                 int num_fcntl_locks, num_flock_locks;
2597                 struct ceph_filelock *flocks;
2598 
2599 encode_again:
2600                 spin_lock(&inode->i_lock);
2601                 ceph_count_locks(inode, &num_fcntl_locks, &num_flock_locks);
2602                 spin_unlock(&inode->i_lock);
2603                 flocks = kmalloc((num_fcntl_locks+num_flock_locks) *
2604                                  sizeof(struct ceph_filelock), GFP_NOFS);
2605                 if (!flocks) {
2606                         err = -ENOMEM;
2607                         goto out_free;
2608                 }
2609                 spin_lock(&inode->i_lock);
2610                 err = ceph_encode_locks_to_buffer(inode, flocks,
2611                                                   num_fcntl_locks,
2612                                                   num_flock_locks);
2613                 spin_unlock(&inode->i_lock);
2614                 if (err) {
2615                         kfree(flocks);
2616                         if (err == -ENOSPC)
2617                                 goto encode_again;
2618                         goto out_free;
2619                 }
2620                 /*
2621                  * number of encoded locks is stable, so copy to pagelist
2622                  */
2623                 rec.v2.flock_len = cpu_to_le32(2*sizeof(u32) +
2624                                     (num_fcntl_locks+num_flock_locks) *
2625                                     sizeof(struct ceph_filelock));
2626                 err = ceph_pagelist_append(pagelist, &rec, reclen);
2627                 if (!err)
2628                         err = ceph_locks_to_pagelist(flocks, pagelist,
2629                                                      num_fcntl_locks,
2630                                                      num_flock_locks);
2631                 kfree(flocks);
2632         } else {
2633                 err = ceph_pagelist_append(pagelist, &rec, reclen);
2634         }
2635 
2636         recon_state->nr_caps++;
2637 out_free:
2638         kfree(path);
2639 out_dput:
2640         dput(dentry);
2641         return err;
2642 }
2643 
2644 
2645 /*
2646  * If an MDS fails and recovers, clients need to reconnect in order to
2647  * reestablish shared state.  This includes all caps issued through
2648  * this session _and_ the snap_realm hierarchy.  Because it's not
2649  * clear which snap realms the mds cares about, we send everything we
2650  * know about.. that ensures we'll then get any new info the
2651  * recovering MDS might have.
2652  *
2653  * This is a relatively heavyweight operation, but it's rare.
2654  *
2655  * called with mdsc->mutex held.
2656  */
2657 static void send_mds_reconnect(struct ceph_mds_client *mdsc,
2658                                struct ceph_mds_session *session)
2659 {
2660         struct ceph_msg *reply;
2661         struct rb_node *p;
2662         int mds = session->s_mds;
2663         int err = -ENOMEM;
2664         int s_nr_caps;
2665         struct ceph_pagelist *pagelist;
2666         struct ceph_reconnect_state recon_state;
2667 
2668         pr_info("mds%d reconnect start\n", mds);
2669 
2670         pagelist = kmalloc(sizeof(*pagelist), GFP_NOFS);
2671         if (!pagelist)
2672                 goto fail_nopagelist;
2673         ceph_pagelist_init(pagelist);
2674 
2675         reply = ceph_msg_new(CEPH_MSG_CLIENT_RECONNECT, 0, GFP_NOFS, false);
2676         if (!reply)
2677                 goto fail_nomsg;
2678 
2679         mutex_lock(&session->s_mutex);
2680         session->s_state = CEPH_MDS_SESSION_RECONNECTING;
2681         session->s_seq = 0;
2682 
2683         ceph_con_close(&session->s_con);
2684         ceph_con_open(&session->s_con,
2685                       CEPH_ENTITY_TYPE_MDS, mds,
2686                       ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
2687 
2688         /* replay unsafe requests */
2689         replay_unsafe_requests(mdsc, session);
2690 
2691         down_read(&mdsc->snap_rwsem);
2692 
2693         dout("session %p state %s\n", session,
2694              session_state_name(session->s_state));
2695 
2696         spin_lock(&session->s_gen_ttl_lock);
2697         session->s_cap_gen++;
2698         spin_unlock(&session->s_gen_ttl_lock);
2699 
2700         spin_lock(&session->s_cap_lock);
2701         /*
2702          * notify __ceph_remove_cap() that we are composing cap reconnect.
2703          * If a cap get released before being added to the cap reconnect,
2704          * __ceph_remove_cap() should skip queuing cap release.
2705          */
2706         session->s_cap_reconnect = 1;
2707         /* drop old cap expires; we're about to reestablish that state */
2708         discard_cap_releases(mdsc, session);
2709         spin_unlock(&session->s_cap_lock);
2710 
2711         /* traverse this session's caps */
2712         s_nr_caps = session->s_nr_caps;
2713         err = ceph_pagelist_encode_32(pagelist, s_nr_caps);
2714         if (err)
2715                 goto fail;
2716 
2717         recon_state.nr_caps = 0;
2718         recon_state.pagelist = pagelist;
2719         recon_state.flock = session->s_con.peer_features & CEPH_FEATURE_FLOCK;
2720         err = iterate_session_caps(session, encode_caps_cb, &recon_state);
2721         if (err < 0)
2722                 goto fail;
2723 
2724         spin_lock(&session->s_cap_lock);
2725         session->s_cap_reconnect = 0;
2726         spin_unlock(&session->s_cap_lock);
2727 
2728         /*
2729          * snaprealms.  we provide mds with the ino, seq (version), and
2730          * parent for all of our realms.  If the mds has any newer info,
2731          * it will tell us.
2732          */
2733         for (p = rb_first(&mdsc->snap_realms); p; p = rb_next(p)) {
2734                 struct ceph_snap_realm *realm =
2735                         rb_entry(p, struct ceph_snap_realm, node);
2736                 struct ceph_mds_snaprealm_reconnect sr_rec;
2737 
2738                 dout(" adding snap realm %llx seq %lld parent %llx\n",
2739                      realm->ino, realm->seq, realm->parent_ino);
2740                 sr_rec.ino = cpu_to_le64(realm->ino);
2741                 sr_rec.seq = cpu_to_le64(realm->seq);
2742                 sr_rec.parent = cpu_to_le64(realm->parent_ino);
2743                 err = ceph_pagelist_append(pagelist, &sr_rec, sizeof(sr_rec));
2744                 if (err)
2745                         goto fail;
2746         }
2747 
2748         if (recon_state.flock)
2749                 reply->hdr.version = cpu_to_le16(2);
2750 
2751         /* raced with cap release? */
2752         if (s_nr_caps != recon_state.nr_caps) {
2753                 struct page *page = list_first_entry(&pagelist->head,
2754                                                      struct page, lru);
2755                 __le32 *addr = kmap_atomic(page);
2756                 *addr = cpu_to_le32(recon_state.nr_caps);
2757                 kunmap_atomic(addr);
2758         }
2759 
2760         reply->hdr.data_len = cpu_to_le32(pagelist->length);
2761         ceph_msg_data_add_pagelist(reply, pagelist);
2762         ceph_con_send(&session->s_con, reply);
2763 
2764         mutex_unlock(&session->s_mutex);
2765 
2766         mutex_lock(&mdsc->mutex);
2767         __wake_requests(mdsc, &session->s_waiting);
2768         mutex_unlock(&mdsc->mutex);
2769 
2770         up_read(&mdsc->snap_rwsem);
2771         return;
2772 
2773 fail:
2774         ceph_msg_put(reply);
2775         up_read(&mdsc->snap_rwsem);
2776         mutex_unlock(&session->s_mutex);
2777 fail_nomsg:
2778         ceph_pagelist_release(pagelist);
2779         kfree(pagelist);
2780 fail_nopagelist:
2781         pr_err("error %d preparing reconnect for mds%d\n", err, mds);
2782         return;
2783 }
2784 
2785 
2786 /*
2787  * compare old and new mdsmaps, kicking requests
2788  * and closing out old connections as necessary
2789  *
2790  * called under mdsc->mutex.
2791  */
2792 static void check_new_map(struct ceph_mds_client *mdsc,
2793                           struct ceph_mdsmap *newmap,
2794                           struct ceph_mdsmap *oldmap)
2795 {
2796         int i;
2797         int oldstate, newstate;
2798         struct ceph_mds_session *s;
2799 
2800         dout("check_new_map new %u old %u\n",
2801              newmap->m_epoch, oldmap->m_epoch);
2802 
2803         for (i = 0; i < oldmap->m_max_mds && i < mdsc->max_sessions; i++) {
2804                 if (mdsc->sessions[i] == NULL)
2805                         continue;
2806                 s = mdsc->sessions[i];
2807                 oldstate = ceph_mdsmap_get_state(oldmap, i);
2808                 newstate = ceph_mdsmap_get_state(newmap, i);
2809 
2810                 dout("check_new_map mds%d state %s%s -> %s%s (session %s)\n",
2811                      i, ceph_mds_state_name(oldstate),
2812                      ceph_mdsmap_is_laggy(oldmap, i) ? " (laggy)" : "",
2813                      ceph_mds_state_name(newstate),
2814                      ceph_mdsmap_is_laggy(newmap, i) ? " (laggy)" : "",
2815                      session_state_name(s->s_state));
2816 
2817                 if (i >= newmap->m_max_mds ||
2818                     memcmp(ceph_mdsmap_get_addr(oldmap, i),
2819                            ceph_mdsmap_get_addr(newmap, i),
2820                            sizeof(struct ceph_entity_addr))) {
2821                         if (s->s_state == CEPH_MDS_SESSION_OPENING) {
2822                                 /* the session never opened, just close it
2823                                  * out now */
2824                                 __wake_requests(mdsc, &s->s_waiting);
2825                                 __unregister_session(mdsc, s);
2826                         } else {
2827                                 /* just close it */
2828                                 mutex_unlock(&mdsc->mutex);
2829                                 mutex_lock(&s->s_mutex);
2830                                 mutex_lock(&mdsc->mutex);
2831                                 ceph_con_close(&s->s_con);
2832                                 mutex_unlock(&s->s_mutex);
2833                                 s->s_state = CEPH_MDS_SESSION_RESTARTING;
2834                         }
2835 
2836                         /* kick any requests waiting on the recovering mds */
2837                         kick_requests(mdsc, i);
2838                 } else if (oldstate == newstate) {
2839                         continue;  /* nothing new with this mds */
2840                 }
2841 
2842                 /*
2843                  * send reconnect?
2844                  */
2845                 if (s->s_state == CEPH_MDS_SESSION_RESTARTING &&
2846                     newstate >= CEPH_MDS_STATE_RECONNECT) {
2847                         mutex_unlock(&mdsc->mutex);
2848                         send_mds_reconnect(mdsc, s);
2849                         mutex_lock(&mdsc->mutex);
2850                 }
2851 
2852                 /*
2853                  * kick request on any mds that has gone active.
2854                  */
2855                 if (oldstate < CEPH_MDS_STATE_ACTIVE &&
2856                     newstate >= CEPH_MDS_STATE_ACTIVE) {
2857                         if (oldstate != CEPH_MDS_STATE_CREATING &&
2858                             oldstate != CEPH_MDS_STATE_STARTING)
2859                                 pr_info("mds%d recovery completed\n", s->s_mds);
2860                         kick_requests(mdsc, i);
2861                         ceph_kick_flushing_caps(mdsc, s);
2862                         wake_up_session_caps(s, 1);
2863                 }
2864         }
2865 
2866         for (i = 0; i < newmap->m_max_mds && i < mdsc->max_sessions; i++) {
2867                 s = mdsc->sessions[i];
2868                 if (!s)
2869                         continue;
2870                 if (!ceph_mdsmap_is_laggy(newmap, i))
2871                         continue;
2872                 if (s->s_state == CEPH_MDS_SESSION_OPEN ||
2873                     s->s_state == CEPH_MDS_SESSION_HUNG ||
2874                     s->s_state == CEPH_MDS_SESSION_CLOSING) {
2875                         dout(" connecting to export targets of laggy mds%d\n",
2876                              i);
2877                         __open_export_target_sessions(mdsc, s);
2878                 }
2879         }
2880 }
2881 
2882 
2883 
2884 /*
2885  * leases
2886  */
2887 
2888 /*
2889  * caller must hold session s_mutex, dentry->d_lock
2890  */
2891 void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry)
2892 {
2893         struct ceph_dentry_info *di = ceph_dentry(dentry);
2894 
2895         ceph_put_mds_session(di->lease_session);
2896         di->lease_session = NULL;
2897 }
2898 
2899 static void handle_lease(struct ceph_mds_client *mdsc,
2900                          struct ceph_mds_session *session,
2901                          struct ceph_msg *msg)
2902 {
2903         struct super_block *sb = mdsc->fsc->sb;
2904         struct inode *inode;
2905         struct dentry *parent, *dentry;
2906         struct ceph_dentry_info *di;
2907         int mds = session->s_mds;
2908         struct ceph_mds_lease *h = msg->front.iov_base;
2909         u32 seq;
2910         struct ceph_vino vino;
2911         struct qstr dname;
2912         int release = 0;
2913 
2914         dout("handle_lease from mds%d\n", mds);
2915 
2916         /* decode */
2917         if (msg->front.iov_len < sizeof(*h) + sizeof(u32))
2918                 goto bad;
2919         vino.ino = le64_to_cpu(h->ino);
2920         vino.snap = CEPH_NOSNAP;
2921         seq = le32_to_cpu(h->seq);
2922         dname.name = (void *)h + sizeof(*h) + sizeof(u32);
2923         dname.len = msg->front.iov_len - sizeof(*h) - sizeof(u32);
2924         if (dname.len != get_unaligned_le32(h+1))
2925                 goto bad;
2926 
2927         mutex_lock(&session->s_mutex);
2928         session->s_seq++;
2929 
2930         /* lookup inode */
2931         inode = ceph_find_inode(sb, vino);
2932         dout("handle_lease %s, ino %llx %p %.*s\n",
2933              ceph_lease_op_name(h->action), vino.ino, inode,
2934              dname.len, dname.name);
2935         if (inode == NULL) {
2936                 dout("handle_lease no inode %llx\n", vino.ino);
2937                 goto release;
2938         }
2939 
2940         /* dentry */
2941         parent = d_find_alias(inode);
2942         if (!parent) {
2943                 dout("no parent dentry on inode %p\n", inode);
2944                 WARN_ON(1);
2945                 goto release;  /* hrm... */
2946         }
2947         dname.hash = full_name_hash(dname.name, dname.len);
2948         dentry = d_lookup(parent, &dname);
2949         dput(parent);
2950         if (!dentry)
2951                 goto release;
2952 
2953         spin_lock(&dentry->d_lock);
2954         di = ceph_dentry(dentry);
2955         switch (h->action) {
2956         case CEPH_MDS_LEASE_REVOKE:
2957                 if (di->lease_session == session) {
2958                         if (ceph_seq_cmp(di->lease_seq, seq) > 0)
2959                                 h->seq = cpu_to_le32(di->lease_seq);
2960                         __ceph_mdsc_drop_dentry_lease(dentry);
2961                 }
2962                 release = 1;
2963                 break;
2964 
2965         case CEPH_MDS_LEASE_RENEW:
2966                 if (di->lease_session == session &&
2967                     di->lease_gen == session->s_cap_gen &&
2968                     di->lease_renew_from &&
2969                     di->lease_renew_after == 0) {
2970                         unsigned long duration =
2971                                 le32_to_cpu(h->duration_ms) * HZ / 1000;
2972 
2973                         di->lease_seq = seq;
2974                         dentry->d_time = di->lease_renew_from + duration;
2975                         di->lease_renew_after = di->lease_renew_from +
2976                                 (duration >> 1);
2977                         di->lease_renew_from = 0;
2978                 }
2979                 break;
2980         }
2981         spin_unlock(&dentry->d_lock);
2982         dput(dentry);
2983 
2984         if (!release)
2985                 goto out;
2986 
2987 release:
2988         /* let's just reuse the same message */
2989         h->action = CEPH_MDS_LEASE_REVOKE_ACK;
2990         ceph_msg_get(msg);
2991         ceph_con_send(&session->s_con, msg);
2992 
2993 out:
2994         iput(inode);
2995         mutex_unlock(&session->s_mutex);
2996         return;
2997 
2998 bad:
2999         pr_err("corrupt lease message\n");
3000         ceph_msg_dump(msg);
3001 }
3002 
3003 void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
3004                               struct inode *inode,
3005                               struct dentry *dentry, char action,
3006                               u32 seq)
3007 {
3008         struct ceph_msg *msg;
3009         struct ceph_mds_lease *lease;
3010         int len = sizeof(*lease) + sizeof(u32);
3011         int dnamelen = 0;
3012 
3013         dout("lease_send_msg inode %p dentry %p %s to mds%d\n",
3014              inode, dentry, ceph_lease_op_name(action), session->s_mds);
3015         dnamelen = dentry->d_name.len;
3016         len += dnamelen;
3017 
3018         msg = ceph_msg_new(CEPH_MSG_CLIENT_LEASE, len, GFP_NOFS, false);
3019         if (!msg)
3020                 return;
3021         lease = msg->front.iov_base;
3022         lease->action = action;
3023         lease->ino = cpu_to_le64(ceph_vino(inode).ino);
3024         lease->first = lease->last = cpu_to_le64(ceph_vino(inode).snap);
3025         lease->seq = cpu_to_le32(seq);
3026         put_unaligned_le32(dnamelen, lease + 1);
3027         memcpy((void *)(lease + 1) + 4, dentry->d_name.name, dnamelen);
3028 
3029         /*
3030          * if this is a preemptive lease RELEASE, no need to
3031          * flush request stream, since the actual request will
3032          * soon follow.
3033          */
3034         msg->more_to_follow = (action == CEPH_MDS_LEASE_RELEASE);
3035 
3036         ceph_con_send(&session->s_con, msg);
3037 }
3038 
3039 /*
3040  * Preemptively release a lease we expect to invalidate anyway.
3041  * Pass @inode always, @dentry is optional.
3042  */
3043 void ceph_mdsc_lease_release(struct ceph_mds_client *mdsc, struct inode *inode,
3044                              struct dentry *dentry)
3045 {
3046         struct ceph_dentry_info *di;
3047         struct ceph_mds_session *session;
3048         u32 seq;
3049 
3050         BUG_ON(inode == NULL);
3051         BUG_ON(dentry == NULL);
3052 
3053         /* is dentry lease valid? */
3054         spin_lock(&dentry->d_lock);
3055         di = ceph_dentry(dentry);
3056         if (!di || !di->lease_session ||
3057             di->lease_session->s_mds < 0 ||
3058             di->lease_gen != di->lease_session->s_cap_gen ||
3059             !time_before(jiffies, dentry->d_time)) {
3060                 dout("lease_release inode %p dentry %p -- "
3061                      "no lease\n",
3062                      inode, dentry);
3063                 spin_unlock(&dentry->d_lock);
3064                 return;
3065         }
3066 
3067         /* we do have a lease on this dentry; note mds and seq */
3068         session = ceph_get_mds_session(di->lease_session);
3069         seq = di->lease_seq;
3070         __ceph_mdsc_drop_dentry_lease(dentry);
3071         spin_unlock(&dentry->d_lock);
3072 
3073         dout("lease_release inode %p dentry %p to mds%d\n",
3074              inode, dentry, session->s_mds);
3075         ceph_mdsc_lease_send_msg(session, inode, dentry,
3076                                  CEPH_MDS_LEASE_RELEASE, seq);
3077         ceph_put_mds_session(session);
3078 }
3079 
3080 /*
3081  * drop all leases (and dentry refs) in preparation for umount
3082  */
3083 static void drop_leases(struct ceph_mds_client *mdsc)
3084 {
3085         int i;
3086 
3087         dout("drop_leases\n");
3088         mutex_lock(&mdsc->mutex);
3089         for (i = 0; i < mdsc->max_sessions; i++) {
3090                 struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
3091                 if (!s)
3092                         continue;
3093                 mutex_unlock(&mdsc->mutex);
3094                 mutex_lock(&s->s_mutex);
3095                 mutex_unlock(&s->s_mutex);
3096                 ceph_put_mds_session(s);
3097                 mutex_lock(&mdsc->mutex);
3098         }
3099         mutex_unlock(&mdsc->mutex);
3100 }
3101 
3102 
3103 
3104 /*
3105  * delayed work -- periodically trim expired leases, renew caps with mds
3106  */
3107 static void schedule_delayed(struct ceph_mds_client *mdsc)
3108 {
3109         int delay = 5;
3110         unsigned hz = round_jiffies_relative(HZ * delay);
3111         schedule_delayed_work(&mdsc->delayed_work, hz);
3112 }
3113 
3114 static void delayed_work(struct work_struct *work)
3115 {
3116         int i;
3117         struct ceph_mds_client *mdsc =
3118                 container_of(work, struct ceph_mds_client, delayed_work.work);
3119         int renew_interval;
3120         int renew_caps;
3121 
3122         dout("mdsc delayed_work\n");
3123         ceph_check_delayed_caps(mdsc);
3124 
3125         mutex_lock(&mdsc->mutex);
3126         renew_interval = mdsc->mdsmap->m_session_timeout >> 2;
3127         renew_caps = time_after_eq(jiffies, HZ*renew_interval +
3128                                    mdsc->last_renew_caps);
3129         if (renew_caps)
3130                 mdsc->last_renew_caps = jiffies;
3131 
3132         for (i = 0; i < mdsc->max_sessions; i++) {
3133                 struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
3134                 if (s == NULL)
3135                         continue;
3136                 if (s->s_state == CEPH_MDS_SESSION_CLOSING) {
3137                         dout("resending session close request for mds%d\n",
3138                              s->s_mds);
3139                         request_close_session(mdsc, s);
3140                         ceph_put_mds_session(s);
3141                         continue;
3142                 }
3143                 if (s->s_ttl && time_after(jiffies, s->s_ttl)) {
3144                         if (s->s_state == CEPH_MDS_SESSION_OPEN) {
3145                                 s->s_state = CEPH_MDS_SESSION_HUNG;
3146                                 pr_info("mds%d hung\n", s->s_mds);
3147                         }
3148                 }
3149                 if (s->s_state < CEPH_MDS_SESSION_OPEN) {
3150                         /* this mds is failed or recovering, just wait */
3151                         ceph_put_mds_session(s);
3152                         continue;
3153                 }
3154                 mutex_unlock(&mdsc->mutex);
3155 
3156                 mutex_lock(&s->s_mutex);
3157                 if (renew_caps)
3158                         send_renew_caps(mdsc, s);
3159                 else
3160                         ceph_con_keepalive(&s->s_con);
3161                 ceph_add_cap_releases(mdsc, s);
3162                 if (s->s_state == CEPH_MDS_SESSION_OPEN ||
3163                     s->s_state == CEPH_MDS_SESSION_HUNG)
3164                         ceph_send_cap_releases(mdsc, s);
3165                 mutex_unlock(&s->s_mutex);
3166                 ceph_put_mds_session(s);
3167 
3168                 mutex_lock(&mdsc->mutex);
3169         }
3170         mutex_unlock(&mdsc->mutex);
3171 
3172         schedule_delayed(mdsc);
3173 }
3174 
3175 int ceph_mdsc_init(struct ceph_fs_client *fsc)
3176 
3177 {
3178         struct ceph_mds_client *mdsc;
3179 
3180         mdsc = kzalloc(sizeof(struct ceph_mds_client), GFP_NOFS);
3181         if (!mdsc)
3182                 return -ENOMEM;
3183         mdsc->fsc = fsc;
3184         fsc->mdsc = mdsc;
3185         mutex_init(&mdsc->mutex);
3186         mdsc->mdsmap = kzalloc(sizeof(*mdsc->mdsmap), GFP_NOFS);
3187         if (mdsc->mdsmap == NULL) {
3188                 kfree(mdsc);
3189                 return -ENOMEM;
3190         }
3191 
3192         init_completion(&mdsc->safe_umount_waiters);
3193         init_waitqueue_head(&mdsc->session_close_wq);
3194         INIT_LIST_HEAD(&mdsc->waiting_for_map);
3195         mdsc->sessions = NULL;
3196         mdsc->max_sessions = 0;
3197         mdsc->stopping = 0;
3198         init_rwsem(&mdsc->snap_rwsem);
3199         mdsc->snap_realms = RB_ROOT;
3200         INIT_LIST_HEAD(&mdsc->snap_empty);
3201         spin_lock_init(&mdsc->snap_empty_lock);
3202         mdsc->last_tid = 0;
3203         mdsc->request_tree = RB_ROOT;
3204         INIT_DELAYED_WORK(&mdsc->delayed_work, delayed_work);
3205         mdsc->last_renew_caps = jiffies;
3206         INIT_LIST_HEAD(&mdsc->cap_delay_list);
3207         spin_lock_init(&mdsc->cap_delay_lock);
3208         INIT_LIST_HEAD(&mdsc->snap_flush_list);
3209         spin_lock_init(&mdsc->snap_flush_lock);
3210         mdsc->cap_flush_seq = 0;
3211         INIT_LIST_HEAD(&mdsc->cap_dirty);
3212         INIT_LIST_HEAD(&mdsc->cap_dirty_migrating);
3213         mdsc->num_cap_flushing = 0;
3214         spin_lock_init(&mdsc->cap_dirty_lock);
3215         init_waitqueue_head(&mdsc->cap_flushing_wq);
3216         spin_lock_init(&mdsc->dentry_lru_lock);
3217         INIT_LIST_HEAD(&mdsc->dentry_lru);
3218 
3219         ceph_caps_init(mdsc);
3220         ceph_adjust_min_caps(mdsc, fsc->min_caps);
3221 
3222         return 0;
3223 }
3224 
3225 /*
3226  * Wait for safe replies on open mds requests.  If we time out, drop
3227  * all requests from the tree to avoid dangling dentry refs.
3228  */
3229 static void wait_requests(struct ceph_mds_client *mdsc)
3230 {
3231         struct ceph_mds_request *req;
3232         struct ceph_fs_client *fsc = mdsc->fsc;
3233 
3234         mutex_lock(&mdsc->mutex);
3235         if (__get_oldest_req(mdsc)) {
3236                 mutex_unlock(&mdsc->mutex);
3237 
3238                 dout("wait_requests waiting for requests\n");
3239                 wait_for_completion_timeout(&mdsc->safe_umount_waiters,
3240                                     fsc->client->options->mount_timeout * HZ);
3241 
3242                 /* tear down remaining requests */
3243                 mutex_lock(&mdsc->mutex);
3244                 while ((req = __get_oldest_req(mdsc))) {
3245                         dout("wait_requests timed out on tid %llu\n",
3246                              req->r_tid);
3247                         __unregister_request(mdsc, req);
3248                 }
3249         }
3250         mutex_unlock(&mdsc->mutex);
3251         dout("wait_requests done\n");
3252 }
3253 
3254 /*
3255  * called before mount is ro, and before dentries are torn down.
3256  * (hmm, does this still race with new lookups?)
3257  */
3258 void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc)
3259 {
3260         dout("pre_umount\n");
3261         mdsc->stopping = 1;
3262 
3263         drop_leases(mdsc);
3264         ceph_flush_dirty_caps(mdsc);
3265         wait_requests(mdsc);
3266 
3267         /*
3268          * wait for reply handlers to drop their request refs and
3269          * their inode/dcache refs
3270          */
3271         ceph_msgr_flush();
3272 }
3273 
3274 /*
3275  * wait for all write mds requests to flush.
3276  */
3277 static void wait_unsafe_requests(struct ceph_mds_client *mdsc, u64 want_tid)
3278 {
3279         struct ceph_mds_request *req = NULL, *nextreq;
3280         struct rb_node *n;
3281 
3282         mutex_lock(&mdsc->mutex);
3283         dout("wait_unsafe_requests want %lld\n", want_tid);
3284 restart:
3285         req = __get_oldest_req(mdsc);
3286         while (req && req->r_tid <= want_tid) {
3287                 /* find next request */
3288                 n = rb_next(&req->r_node);
3289                 if (n)
3290                         nextreq = rb_entry(n, struct ceph_mds_request, r_node);
3291                 else
3292                         nextreq = NULL;
3293                 if ((req->r_op & CEPH_MDS_OP_WRITE)) {
3294                         /* write op */
3295                         ceph_mdsc_get_request(req);
3296                         if (nextreq)
3297                                 ceph_mdsc_get_request(nextreq);
3298                         mutex_unlock(&mdsc->mutex);
3299                         dout("wait_unsafe_requests  wait on %llu (want %llu)\n",
3300                              req->r_tid, want_tid);
3301                         wait_for_completion(&req->r_safe_completion);
3302                         mutex_lock(&mdsc->mutex);
3303                         ceph_mdsc_put_request(req);
3304                         if (!nextreq)
3305                                 break;  /* next dne before, so we're done! */
3306                         if (RB_EMPTY_NODE(&nextreq->r_node)) {
3307                                 /* next request was removed from tree */
3308                                 ceph_mdsc_put_request(nextreq);
3309                                 goto restart;
3310                         }
3311                         ceph_mdsc_put_request(nextreq);  /* won't go away */
3312                 }
3313                 req = nextreq;
3314         }
3315         mutex_unlock(&mdsc->mutex);
3316         dout("wait_unsafe_requests done\n");
3317 }
3318 
3319 void ceph_mdsc_sync(struct ceph_mds_client *mdsc)
3320 {
3321         u64 want_tid, want_flush;
3322 
3323         if (mdsc->fsc->mount_state == CEPH_MOUNT_SHUTDOWN)
3324                 return;
3325 
3326         dout("sync\n");
3327         mutex_lock(&mdsc->mutex);
3328         want_tid = mdsc->last_tid;
3329         want_flush = mdsc->cap_flush_seq;
3330         mutex_unlock(&mdsc->mutex);
3331         dout("sync want tid %lld flush_seq %lld\n", want_tid, want_flush);
3332 
3333         ceph_flush_dirty_caps(mdsc);
3334 
3335         wait_unsafe_requests(mdsc, want_tid);
3336         wait_event(mdsc->cap_flushing_wq, check_cap_flush(mdsc, want_flush));
3337 }
3338 
3339 /*
3340  * true if all sessions are closed, or we force unmount
3341  */
3342 static bool done_closing_sessions(struct ceph_mds_client *mdsc)
3343 {
3344         int i, n = 0;
3345 
3346         if (mdsc->fsc->mount_state == CEPH_MOUNT_SHUTDOWN)
3347                 return true;
3348 
3349         mutex_lock(&mdsc->mutex);
3350         for (i = 0; i < mdsc->max_sessions; i++)
3351                 if (mdsc->sessions[i])
3352                         n++;
3353         mutex_unlock(&mdsc->mutex);
3354         return n == 0;
3355 }
3356 
3357 /*
3358  * called after sb is ro.
3359  */
3360 void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc)
3361 {
3362         struct ceph_mds_session *session;
3363         int i;
3364         struct ceph_fs_client *fsc = mdsc->fsc;
3365         unsigned long timeout = fsc->client->options->mount_timeout * HZ;
3366 
3367         dout("close_sessions\n");
3368 
3369         /* close sessions */
3370         mutex_lock(&mdsc->mutex);
3371         for (i = 0; i < mdsc->max_sessions; i++) {
3372                 session = __ceph_lookup_mds_session(mdsc, i);
3373                 if (!session)
3374                         continue;
3375                 mutex_unlock(&mdsc->mutex);
3376                 mutex_lock(&session->s_mutex);
3377                 __close_session(mdsc, session);
3378                 mutex_unlock(&session->s_mutex);
3379                 ceph_put_mds_session(session);
3380                 mutex_lock(&mdsc->mutex);
3381         }
3382         mutex_unlock(&mdsc->mutex);
3383 
3384         dout("waiting for sessions to close\n");
3385         wait_event_timeout(mdsc->session_close_wq, done_closing_sessions(mdsc),
3386                            timeout);
3387 
3388         /* tear down remaining sessions */
3389         mutex_lock(&mdsc->mutex);
3390         for (i = 0; i < mdsc->max_sessions; i++) {
3391                 if (mdsc->sessions[i]) {
3392                         session = get_session(mdsc->sessions[i]);
3393                         __unregister_session(mdsc, session);
3394                         mutex_unlock(&mdsc->mutex);
3395                         mutex_lock(&session->s_mutex);
3396                         remove_session_caps(session);
3397                         mutex_unlock(&session->s_mutex);
3398                         ceph_put_mds_session(session);
3399                         mutex_lock(&mdsc->mutex);
3400                 }
3401         }
3402         WARN_ON(!list_empty(&mdsc->cap_delay_list));
3403         mutex_unlock(&mdsc->mutex);
3404 
3405         ceph_cleanup_empty_realms(mdsc);
3406 
3407         cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
3408 
3409         dout("stopped\n");
3410 }
3411 
3412 static void ceph_mdsc_stop(struct ceph_mds_client *mdsc)
3413 {
3414         dout("stop\n");
3415         cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
3416         if (mdsc->mdsmap)
3417                 ceph_mdsmap_destroy(mdsc->mdsmap);
3418         kfree(mdsc->sessions);
3419         ceph_caps_finalize(mdsc);
3420 }
3421 
3422 void ceph_mdsc_destroy(struct ceph_fs_client *fsc)
3423 {
3424         struct ceph_mds_client *mdsc = fsc->mdsc;
3425 
3426         dout("mdsc_destroy %p\n", mdsc);
3427         ceph_mdsc_stop(mdsc);
3428 
3429         /* flush out any connection work with references to us */
3430         ceph_msgr_flush();
3431 
3432         fsc->mdsc = NULL;
3433         kfree(mdsc);
3434         dout("mdsc_destroy %p done\n", mdsc);
3435 }
3436 
3437 
3438 /*
3439  * handle mds map update.
3440  */
3441 void ceph_mdsc_handle_map(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
3442 {
3443         u32 epoch;
3444         u32 maplen;
3445         void *p = msg->front.iov_base;
3446         void *end = p + msg->front.iov_len;
3447         struct ceph_mdsmap *newmap, *oldmap;
3448         struct ceph_fsid fsid;
3449         int err = -EINVAL;
3450 
3451         ceph_decode_need(&p, end, sizeof(fsid)+2*sizeof(u32), bad);
3452         ceph_decode_copy(&p, &fsid, sizeof(fsid));
3453         if (ceph_check_fsid(mdsc->fsc->client, &fsid) < 0)
3454                 return;
3455         epoch = ceph_decode_32(&p);
3456         maplen = ceph_decode_32(&p);
3457         dout("handle_map epoch %u len %d\n", epoch, (int)maplen);
3458 
3459         /* do we need it? */
3460         ceph_monc_got_mdsmap(&mdsc->fsc->client->monc, epoch);
3461         mutex_lock(&mdsc->mutex);
3462         if (mdsc->mdsmap && epoch <= mdsc->mdsmap->m_epoch) {
3463                 dout("handle_map epoch %u <= our %u\n",
3464                      epoch, mdsc->mdsmap->m_epoch);
3465                 mutex_unlock(&mdsc->mutex);
3466                 return;
3467         }
3468 
3469         newmap = ceph_mdsmap_decode(&p, end);
3470         if (IS_ERR(newmap)) {
3471                 err = PTR_ERR(newmap);
3472                 goto bad_unlock;
3473         }
3474 
3475         /* swap into place */
3476         if (mdsc->mdsmap) {
3477                 oldmap = mdsc->mdsmap;
3478                 mdsc->mdsmap = newmap;
3479                 check_new_map(mdsc, newmap, oldmap);
3480                 ceph_mdsmap_destroy(oldmap);
3481         } else {
3482                 mdsc->mdsmap = newmap;  /* first mds map */
3483         }
3484         mdsc->fsc->sb->s_maxbytes = mdsc->mdsmap->m_max_file_size;
3485 
3486         __wake_requests(mdsc, &mdsc->waiting_for_map);
3487 
3488         mutex_unlock(&mdsc->mutex);
3489         schedule_delayed(mdsc);
3490         return;
3491 
3492 bad_unlock:
3493         mutex_unlock(&mdsc->mutex);
3494 bad:
3495         pr_err("error decoding mdsmap %d\n", err);
3496         return;
3497 }
3498 
3499 static struct ceph_connection *con_get(struct ceph_connection *con)
3500 {
3501         struct ceph_mds_session *s = con->private;
3502 
3503         if (get_session(s)) {
3504                 dout("mdsc con_get %p ok (%d)\n", s, atomic_read(&s->s_ref));
3505                 return con;
3506         }
3507         dout("mdsc con_get %p FAIL\n", s);
3508         return NULL;
3509 }
3510 
3511 static void con_put(struct ceph_connection *con)
3512 {
3513         struct ceph_mds_session *s = con->private;
3514 
3515         dout("mdsc con_put %p (%d)\n", s, atomic_read(&s->s_ref) - 1);
3516         ceph_put_mds_session(s);
3517 }
3518 
3519 /*
3520  * if the client is unresponsive for long enough, the mds will kill
3521  * the session entirely.
3522  */
3523 static void peer_reset(struct ceph_connection *con)
3524 {
3525         struct ceph_mds_session *s = con->private;
3526         struct ceph_mds_client *mdsc = s->s_mdsc;
3527 
3528         pr_warning("mds%d closed our session\n", s->s_mds);
3529         send_mds_reconnect(mdsc, s);
3530 }
3531 
3532 static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
3533 {
3534         struct ceph_mds_session *s = con->private;
3535         struct ceph_mds_client *mdsc = s->s_mdsc;
3536         int type = le16_to_cpu(msg->hdr.type);
3537 
3538         mutex_lock(&mdsc->mutex);
3539         if (__verify_registered_session(mdsc, s) < 0) {
3540                 mutex_unlock(&mdsc->mutex);
3541                 goto out;
3542         }
3543         mutex_unlock(&mdsc->mutex);
3544 
3545         switch (type) {
3546         case CEPH_MSG_MDS_MAP:
3547                 ceph_mdsc_handle_map(mdsc, msg);
3548                 break;
3549         case CEPH_MSG_CLIENT_SESSION:
3550                 handle_session(s, msg);
3551                 break;
3552         case CEPH_MSG_CLIENT_REPLY:
3553                 handle_reply(s, msg);
3554                 break;
3555         case CEPH_MSG_CLIENT_REQUEST_FORWARD:
3556                 handle_forward(mdsc, s, msg);
3557                 break;
3558         case CEPH_MSG_CLIENT_CAPS:
3559                 ceph_handle_caps(s, msg);
3560                 break;
3561         case CEPH_MSG_CLIENT_SNAP:
3562                 ceph_handle_snap(mdsc, s, msg);
3563                 break;
3564         case CEPH_MSG_CLIENT_LEASE:
3565                 handle_lease(mdsc, s, msg);
3566                 break;
3567 
3568         default:
3569                 pr_err("received unknown message type %d %s\n", type,
3570                        ceph_msg_type_name(type));
3571         }
3572 out:
3573         ceph_msg_put(msg);
3574 }
3575 
3576 /*
3577  * authentication
3578  */
3579 
3580 /*
3581  * Note: returned pointer is the address of a structure that's
3582  * managed separately.  Caller must *not* attempt to free it.
3583  */
3584 static struct ceph_auth_handshake *get_authorizer(struct ceph_connection *con,
3585                                         int *proto, int force_new)
3586 {
3587         struct ceph_mds_session *s = con->private;
3588         struct ceph_mds_client *mdsc = s->s_mdsc;
3589         struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
3590         struct ceph_auth_handshake *auth = &s->s_auth;
3591 
3592         if (force_new && auth->authorizer) {
3593                 ceph_auth_destroy_authorizer(ac, auth->authorizer);
3594                 auth->authorizer = NULL;
3595         }
3596         if (!auth->authorizer) {
3597                 int ret = ceph_auth_create_authorizer(ac, CEPH_ENTITY_TYPE_MDS,
3598                                                       auth);
3599                 if (ret)
3600                         return ERR_PTR(ret);
3601         } else {
3602                 int ret = ceph_auth_update_authorizer(ac, CEPH_ENTITY_TYPE_MDS,
3603                                                       auth);
3604                 if (ret)
3605                         return ERR_PTR(ret);
3606         }
3607         *proto = ac->protocol;
3608 
3609         return auth;
3610 }
3611 
3612 
3613 static int verify_authorizer_reply(struct ceph_connection *con, int len)
3614 {
3615         struct ceph_mds_session *s = con->private;
3616         struct ceph_mds_client *mdsc = s->s_mdsc;
3617         struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
3618 
3619         return ceph_auth_verify_authorizer_reply(ac, s->s_auth.authorizer, len);
3620 }
3621 
3622 static int invalidate_authorizer(struct ceph_connection *con)
3623 {
3624         struct ceph_mds_session *s = con->private;
3625         struct ceph_mds_client *mdsc = s->s_mdsc;
3626         struct ceph_auth_client *ac = mdsc->fsc->client->monc.auth;
3627 
3628         ceph_auth_invalidate_authorizer(ac, CEPH_ENTITY_TYPE_MDS);
3629 
3630         return ceph_monc_validate_auth(&mdsc->fsc->client->monc);
3631 }
3632 
3633 static struct ceph_msg *mds_alloc_msg(struct ceph_connection *con,
3634                                 struct ceph_msg_header *hdr, int *skip)
3635 {
3636         struct ceph_msg *msg;
3637         int type = (int) le16_to_cpu(hdr->type);
3638         int front_len = (int) le32_to_cpu(hdr->front_len);
3639 
3640         if (con->in_msg)
3641                 return con->in_msg;
3642 
3643         *skip = 0;
3644         msg = ceph_msg_new(type, front_len, GFP_NOFS, false);
3645         if (!msg) {
3646                 pr_err("unable to allocate msg type %d len %d\n",
3647                        type, front_len);
3648                 return NULL;
3649         }
3650 
3651         return msg;
3652 }
3653 
3654 static const struct ceph_connection_operations mds_con_ops = {
3655         .get = con_get,
3656         .put = con_put,
3657         .dispatch = dispatch,
3658         .get_authorizer = get_authorizer,
3659         .verify_authorizer_reply = verify_authorizer_reply,
3660         .invalidate_authorizer = invalidate_authorizer,
3661         .peer_reset = peer_reset,
3662         .alloc_msg = mds_alloc_msg,
3663 };
3664 
3665 /* eof */
3666 

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