ceph: drop messages on unregistered mds sessions; cleanup
[linux-2.6.git] / fs / ceph / mds_client.c
1 #include "ceph_debug.h"
2
3 #include <linux/wait.h>
4 #include <linux/sched.h>
5
6 #include "mds_client.h"
7 #include "mon_client.h"
8 #include "super.h"
9 #include "messenger.h"
10 #include "decode.h"
11 #include "auth.h"
12 #include "pagelist.h"
13
14 /*
15  * A cluster of MDS (metadata server) daemons is responsible for
16  * managing the file system namespace (the directory hierarchy and
17  * inodes) and for coordinating shared access to storage.  Metadata is
18  * partitioning hierarchically across a number of servers, and that
19  * partition varies over time as the cluster adjusts the distribution
20  * in order to balance load.
21  *
22  * The MDS client is primarily responsible to managing synchronous
23  * metadata requests for operations like open, unlink, and so forth.
24  * If there is a MDS failure, we find out about it when we (possibly
25  * request and) receive a new MDS map, and can resubmit affected
26  * requests.
27  *
28  * For the most part, though, we take advantage of a lossless
29  * communications channel to the MDS, and do not need to worry about
30  * timing out or resubmitting requests.
31  *
32  * We maintain a stateful "session" with each MDS we interact with.
33  * Within each session, we sent periodic heartbeat messages to ensure
34  * any capabilities or leases we have been issues remain valid.  If
35  * the session times out and goes stale, our leases and capabilities
36  * are no longer valid.
37  */
38
39 static void __wake_requests(struct ceph_mds_client *mdsc,
40                             struct list_head *head);
41
42 const static struct ceph_connection_operations mds_con_ops;
43
44
45 /*
46  * mds reply parsing
47  */
48
49 /*
50  * parse individual inode info
51  */
52 static int parse_reply_info_in(void **p, void *end,
53                                struct ceph_mds_reply_info_in *info)
54 {
55         int err = -EIO;
56
57         info->in = *p;
58         *p += sizeof(struct ceph_mds_reply_inode) +
59                 sizeof(*info->in->fragtree.splits) *
60                 le32_to_cpu(info->in->fragtree.nsplits);
61
62         ceph_decode_32_safe(p, end, info->symlink_len, bad);
63         ceph_decode_need(p, end, info->symlink_len, bad);
64         info->symlink = *p;
65         *p += info->symlink_len;
66
67         ceph_decode_32_safe(p, end, info->xattr_len, bad);
68         ceph_decode_need(p, end, info->xattr_len, bad);
69         info->xattr_data = *p;
70         *p += info->xattr_len;
71         return 0;
72 bad:
73         return err;
74 }
75
76 /*
77  * parse a normal reply, which may contain a (dir+)dentry and/or a
78  * target inode.
79  */
80 static int parse_reply_info_trace(void **p, void *end,
81                                   struct ceph_mds_reply_info_parsed *info)
82 {
83         int err;
84
85         if (info->head->is_dentry) {
86                 err = parse_reply_info_in(p, end, &info->diri);
87                 if (err < 0)
88                         goto out_bad;
89
90                 if (unlikely(*p + sizeof(*info->dirfrag) > end))
91                         goto bad;
92                 info->dirfrag = *p;
93                 *p += sizeof(*info->dirfrag) +
94                         sizeof(u32)*le32_to_cpu(info->dirfrag->ndist);
95                 if (unlikely(*p > end))
96                         goto bad;
97
98                 ceph_decode_32_safe(p, end, info->dname_len, bad);
99                 ceph_decode_need(p, end, info->dname_len, bad);
100                 info->dname = *p;
101                 *p += info->dname_len;
102                 info->dlease = *p;
103                 *p += sizeof(*info->dlease);
104         }
105
106         if (info->head->is_target) {
107                 err = parse_reply_info_in(p, end, &info->targeti);
108                 if (err < 0)
109                         goto out_bad;
110         }
111
112         if (unlikely(*p != end))
113                 goto bad;
114         return 0;
115
116 bad:
117         err = -EIO;
118 out_bad:
119         pr_err("problem parsing mds trace %d\n", err);
120         return err;
121 }
122
123 /*
124  * parse readdir results
125  */
126 static int parse_reply_info_dir(void **p, void *end,
127                                 struct ceph_mds_reply_info_parsed *info)
128 {
129         u32 num, i = 0;
130         int err;
131
132         info->dir_dir = *p;
133         if (*p + sizeof(*info->dir_dir) > end)
134                 goto bad;
135         *p += sizeof(*info->dir_dir) +
136                 sizeof(u32)*le32_to_cpu(info->dir_dir->ndist);
137         if (*p > end)
138                 goto bad;
139
140         ceph_decode_need(p, end, sizeof(num) + 2, bad);
141         num = ceph_decode_32(p);
142         info->dir_end = ceph_decode_8(p);
143         info->dir_complete = ceph_decode_8(p);
144         if (num == 0)
145                 goto done;
146
147         /* alloc large array */
148         info->dir_nr = num;
149         info->dir_in = kcalloc(num, sizeof(*info->dir_in) +
150                                sizeof(*info->dir_dname) +
151                                sizeof(*info->dir_dname_len) +
152                                sizeof(*info->dir_dlease),
153                                GFP_NOFS);
154         if (info->dir_in == NULL) {
155                 err = -ENOMEM;
156                 goto out_bad;
157         }
158         info->dir_dname = (void *)(info->dir_in + num);
159         info->dir_dname_len = (void *)(info->dir_dname + num);
160         info->dir_dlease = (void *)(info->dir_dname_len + num);
161
162         while (num) {
163                 /* dentry */
164                 ceph_decode_need(p, end, sizeof(u32)*2, bad);
165                 info->dir_dname_len[i] = ceph_decode_32(p);
166                 ceph_decode_need(p, end, info->dir_dname_len[i], bad);
167                 info->dir_dname[i] = *p;
168                 *p += info->dir_dname_len[i];
169                 dout("parsed dir dname '%.*s'\n", info->dir_dname_len[i],
170                      info->dir_dname[i]);
171                 info->dir_dlease[i] = *p;
172                 *p += sizeof(struct ceph_mds_reply_lease);
173
174                 /* inode */
175                 err = parse_reply_info_in(p, end, &info->dir_in[i]);
176                 if (err < 0)
177                         goto out_bad;
178                 i++;
179                 num--;
180         }
181
182 done:
183         if (*p != end)
184                 goto bad;
185         return 0;
186
187 bad:
188         err = -EIO;
189 out_bad:
190         pr_err("problem parsing dir contents %d\n", err);
191         return err;
192 }
193
194 /*
195  * parse entire mds reply
196  */
197 static int parse_reply_info(struct ceph_msg *msg,
198                             struct ceph_mds_reply_info_parsed *info)
199 {
200         void *p, *end;
201         u32 len;
202         int err;
203
204         info->head = msg->front.iov_base;
205         p = msg->front.iov_base + sizeof(struct ceph_mds_reply_head);
206         end = p + msg->front.iov_len - sizeof(struct ceph_mds_reply_head);
207
208         /* trace */
209         ceph_decode_32_safe(&p, end, len, bad);
210         if (len > 0) {
211                 err = parse_reply_info_trace(&p, p+len, info);
212                 if (err < 0)
213                         goto out_bad;
214         }
215
216         /* dir content */
217         ceph_decode_32_safe(&p, end, len, bad);
218         if (len > 0) {
219                 err = parse_reply_info_dir(&p, p+len, info);
220                 if (err < 0)
221                         goto out_bad;
222         }
223
224         /* snap blob */
225         ceph_decode_32_safe(&p, end, len, bad);
226         info->snapblob_len = len;
227         info->snapblob = p;
228         p += len;
229
230         if (p != end)
231                 goto bad;
232         return 0;
233
234 bad:
235         err = -EIO;
236 out_bad:
237         pr_err("mds parse_reply err %d\n", err);
238         return err;
239 }
240
241 static void destroy_reply_info(struct ceph_mds_reply_info_parsed *info)
242 {
243         kfree(info->dir_in);
244 }
245
246
247 /*
248  * sessions
249  */
250 static const char *session_state_name(int s)
251 {
252         switch (s) {
253         case CEPH_MDS_SESSION_NEW: return "new";
254         case CEPH_MDS_SESSION_OPENING: return "opening";
255         case CEPH_MDS_SESSION_OPEN: return "open";
256         case CEPH_MDS_SESSION_HUNG: return "hung";
257         case CEPH_MDS_SESSION_CLOSING: return "closing";
258         case CEPH_MDS_SESSION_RESTARTING: return "restarting";
259         case CEPH_MDS_SESSION_RECONNECTING: return "reconnecting";
260         default: return "???";
261         }
262 }
263
264 static struct ceph_mds_session *get_session(struct ceph_mds_session *s)
265 {
266         if (atomic_inc_not_zero(&s->s_ref)) {
267                 dout("mdsc get_session %p %d -> %d\n", s,
268                      atomic_read(&s->s_ref)-1, atomic_read(&s->s_ref));
269                 return s;
270         } else {
271                 dout("mdsc get_session %p 0 -- FAIL", s);
272                 return NULL;
273         }
274 }
275
276 void ceph_put_mds_session(struct ceph_mds_session *s)
277 {
278         dout("mdsc put_session %p %d -> %d\n", s,
279              atomic_read(&s->s_ref), atomic_read(&s->s_ref)-1);
280         if (atomic_dec_and_test(&s->s_ref)) {
281                 if (s->s_authorizer)
282                         s->s_mdsc->client->monc.auth->ops->destroy_authorizer(
283                                 s->s_mdsc->client->monc.auth, s->s_authorizer);
284                 kfree(s);
285         }
286 }
287
288 /*
289  * called under mdsc->mutex
290  */
291 struct ceph_mds_session *__ceph_lookup_mds_session(struct ceph_mds_client *mdsc,
292                                                    int mds)
293 {
294         struct ceph_mds_session *session;
295
296         if (mds >= mdsc->max_sessions || mdsc->sessions[mds] == NULL)
297                 return NULL;
298         session = mdsc->sessions[mds];
299         dout("lookup_mds_session %p %d\n", session,
300              atomic_read(&session->s_ref));
301         get_session(session);
302         return session;
303 }
304
305 static bool __have_session(struct ceph_mds_client *mdsc, int mds)
306 {
307         if (mds >= mdsc->max_sessions)
308                 return false;
309         return mdsc->sessions[mds];
310 }
311
312 static int __verify_registered_session(struct ceph_mds_client *mdsc,
313                                        struct ceph_mds_session *s)
314 {
315         if (s->s_mds >= mdsc->max_sessions ||
316             mdsc->sessions[s->s_mds] != s)
317                 return -ENOENT;
318         return 0;
319 }
320
321 /*
322  * create+register a new session for given mds.
323  * called under mdsc->mutex.
324  */
325 static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
326                                                  int mds)
327 {
328         struct ceph_mds_session *s;
329
330         s = kzalloc(sizeof(*s), GFP_NOFS);
331         s->s_mdsc = mdsc;
332         s->s_mds = mds;
333         s->s_state = CEPH_MDS_SESSION_NEW;
334         s->s_ttl = 0;
335         s->s_seq = 0;
336         mutex_init(&s->s_mutex);
337
338         ceph_con_init(mdsc->client->msgr, &s->s_con);
339         s->s_con.private = s;
340         s->s_con.ops = &mds_con_ops;
341         s->s_con.peer_name.type = CEPH_ENTITY_TYPE_MDS;
342         s->s_con.peer_name.num = cpu_to_le64(mds);
343
344         spin_lock_init(&s->s_cap_lock);
345         s->s_cap_gen = 0;
346         s->s_cap_ttl = 0;
347         s->s_renew_requested = 0;
348         s->s_renew_seq = 0;
349         INIT_LIST_HEAD(&s->s_caps);
350         s->s_nr_caps = 0;
351         s->s_trim_caps = 0;
352         atomic_set(&s->s_ref, 1);
353         INIT_LIST_HEAD(&s->s_waiting);
354         INIT_LIST_HEAD(&s->s_unsafe);
355         s->s_num_cap_releases = 0;
356         s->s_cap_iterator = NULL;
357         INIT_LIST_HEAD(&s->s_cap_releases);
358         INIT_LIST_HEAD(&s->s_cap_releases_done);
359         INIT_LIST_HEAD(&s->s_cap_flushing);
360         INIT_LIST_HEAD(&s->s_cap_snaps_flushing);
361
362         dout("register_session mds%d\n", mds);
363         if (mds >= mdsc->max_sessions) {
364                 int newmax = 1 << get_count_order(mds+1);
365                 struct ceph_mds_session **sa;
366
367                 dout("register_session realloc to %d\n", newmax);
368                 sa = kcalloc(newmax, sizeof(void *), GFP_NOFS);
369                 if (sa == NULL)
370                         goto fail_realloc;
371                 if (mdsc->sessions) {
372                         memcpy(sa, mdsc->sessions,
373                                mdsc->max_sessions * sizeof(void *));
374                         kfree(mdsc->sessions);
375                 }
376                 mdsc->sessions = sa;
377                 mdsc->max_sessions = newmax;
378         }
379         mdsc->sessions[mds] = s;
380         atomic_inc(&s->s_ref);  /* one ref to sessions[], one to caller */
381
382         ceph_con_open(&s->s_con, ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
383
384         return s;
385
386 fail_realloc:
387         kfree(s);
388         return ERR_PTR(-ENOMEM);
389 }
390
391 /*
392  * called under mdsc->mutex
393  */
394 static void __unregister_session(struct ceph_mds_client *mdsc,
395                                struct ceph_mds_session *s)
396 {
397         dout("__unregister_session mds%d %p\n", s->s_mds, s);
398         BUG_ON(mdsc->sessions[s->s_mds] != s);
399         mdsc->sessions[s->s_mds] = NULL;
400         ceph_con_close(&s->s_con);
401         ceph_put_mds_session(s);
402 }
403
404 /*
405  * drop session refs in request.
406  *
407  * should be last request ref, or hold mdsc->mutex
408  */
409 static void put_request_session(struct ceph_mds_request *req)
410 {
411         if (req->r_session) {
412                 ceph_put_mds_session(req->r_session);
413                 req->r_session = NULL;
414         }
415 }
416
417 void ceph_mdsc_release_request(struct kref *kref)
418 {
419         struct ceph_mds_request *req = container_of(kref,
420                                                     struct ceph_mds_request,
421                                                     r_kref);
422         if (req->r_request)
423                 ceph_msg_put(req->r_request);
424         if (req->r_reply) {
425                 ceph_msg_put(req->r_reply);
426                 destroy_reply_info(&req->r_reply_info);
427         }
428         if (req->r_inode) {
429                 ceph_put_cap_refs(ceph_inode(req->r_inode),
430                                   CEPH_CAP_PIN);
431                 iput(req->r_inode);
432         }
433         if (req->r_locked_dir)
434                 ceph_put_cap_refs(ceph_inode(req->r_locked_dir),
435                                   CEPH_CAP_PIN);
436         if (req->r_target_inode)
437                 iput(req->r_target_inode);
438         if (req->r_dentry)
439                 dput(req->r_dentry);
440         if (req->r_old_dentry) {
441                 ceph_put_cap_refs(
442                         ceph_inode(req->r_old_dentry->d_parent->d_inode),
443                         CEPH_CAP_PIN);
444                 dput(req->r_old_dentry);
445         }
446         kfree(req->r_path1);
447         kfree(req->r_path2);
448         put_request_session(req);
449         ceph_unreserve_caps(&req->r_caps_reservation);
450         kfree(req);
451 }
452
453 /*
454  * lookup session, bump ref if found.
455  *
456  * called under mdsc->mutex.
457  */
458 static struct ceph_mds_request *__lookup_request(struct ceph_mds_client *mdsc,
459                                              u64 tid)
460 {
461         struct ceph_mds_request *req;
462         struct rb_node *n = mdsc->request_tree.rb_node;
463
464         while (n) {
465                 req = rb_entry(n, struct ceph_mds_request, r_node);
466                 if (tid < req->r_tid)
467                         n = n->rb_left;
468                 else if (tid > req->r_tid)
469                         n = n->rb_right;
470                 else {
471                         ceph_mdsc_get_request(req);
472                         return req;
473                 }
474         }
475         return NULL;
476 }
477
478 static void __insert_request(struct ceph_mds_client *mdsc,
479                              struct ceph_mds_request *new)
480 {
481         struct rb_node **p = &mdsc->request_tree.rb_node;
482         struct rb_node *parent = NULL;
483         struct ceph_mds_request *req = NULL;
484
485         while (*p) {
486                 parent = *p;
487                 req = rb_entry(parent, struct ceph_mds_request, r_node);
488                 if (new->r_tid < req->r_tid)
489                         p = &(*p)->rb_left;
490                 else if (new->r_tid > req->r_tid)
491                         p = &(*p)->rb_right;
492                 else
493                         BUG();
494         }
495
496         rb_link_node(&new->r_node, parent, p);
497         rb_insert_color(&new->r_node, &mdsc->request_tree);
498 }
499
500 /*
501  * Register an in-flight request, and assign a tid.  Link to directory
502  * are modifying (if any).
503  *
504  * Called under mdsc->mutex.
505  */
506 static void __register_request(struct ceph_mds_client *mdsc,
507                                struct ceph_mds_request *req,
508                                struct inode *dir)
509 {
510         req->r_tid = ++mdsc->last_tid;
511         if (req->r_num_caps)
512                 ceph_reserve_caps(&req->r_caps_reservation, req->r_num_caps);
513         dout("__register_request %p tid %lld\n", req, req->r_tid);
514         ceph_mdsc_get_request(req);
515         __insert_request(mdsc, req);
516
517         if (dir) {
518                 struct ceph_inode_info *ci = ceph_inode(dir);
519
520                 spin_lock(&ci->i_unsafe_lock);
521                 req->r_unsafe_dir = dir;
522                 list_add_tail(&req->r_unsafe_dir_item, &ci->i_unsafe_dirops);
523                 spin_unlock(&ci->i_unsafe_lock);
524         }
525 }
526
527 static void __unregister_request(struct ceph_mds_client *mdsc,
528                                  struct ceph_mds_request *req)
529 {
530         dout("__unregister_request %p tid %lld\n", req, req->r_tid);
531         rb_erase(&req->r_node, &mdsc->request_tree);
532         ceph_mdsc_put_request(req);
533
534         if (req->r_unsafe_dir) {
535                 struct ceph_inode_info *ci = ceph_inode(req->r_unsafe_dir);
536
537                 spin_lock(&ci->i_unsafe_lock);
538                 list_del_init(&req->r_unsafe_dir_item);
539                 spin_unlock(&ci->i_unsafe_lock);
540         }
541 }
542
543 /*
544  * Choose mds to send request to next.  If there is a hint set in the
545  * request (e.g., due to a prior forward hint from the mds), use that.
546  * Otherwise, consult frag tree and/or caps to identify the
547  * appropriate mds.  If all else fails, choose randomly.
548  *
549  * Called under mdsc->mutex.
550  */
551 static int __choose_mds(struct ceph_mds_client *mdsc,
552                         struct ceph_mds_request *req)
553 {
554         struct inode *inode;
555         struct ceph_inode_info *ci;
556         struct ceph_cap *cap;
557         int mode = req->r_direct_mode;
558         int mds = -1;
559         u32 hash = req->r_direct_hash;
560         bool is_hash = req->r_direct_is_hash;
561
562         /*
563          * is there a specific mds we should try?  ignore hint if we have
564          * no session and the mds is not up (active or recovering).
565          */
566         if (req->r_resend_mds >= 0 &&
567             (__have_session(mdsc, req->r_resend_mds) ||
568              ceph_mdsmap_get_state(mdsc->mdsmap, req->r_resend_mds) > 0)) {
569                 dout("choose_mds using resend_mds mds%d\n",
570                      req->r_resend_mds);
571                 return req->r_resend_mds;
572         }
573
574         if (mode == USE_RANDOM_MDS)
575                 goto random;
576
577         inode = NULL;
578         if (req->r_inode) {
579                 inode = req->r_inode;
580         } else if (req->r_dentry) {
581                 if (req->r_dentry->d_inode) {
582                         inode = req->r_dentry->d_inode;
583                 } else {
584                         inode = req->r_dentry->d_parent->d_inode;
585                         hash = req->r_dentry->d_name.hash;
586                         is_hash = true;
587                 }
588         }
589         dout("__choose_mds %p is_hash=%d (%d) mode %d\n", inode, (int)is_hash,
590              (int)hash, mode);
591         if (!inode)
592                 goto random;
593         ci = ceph_inode(inode);
594
595         if (is_hash && S_ISDIR(inode->i_mode)) {
596                 struct ceph_inode_frag frag;
597                 int found;
598
599                 ceph_choose_frag(ci, hash, &frag, &found);
600                 if (found) {
601                         if (mode == USE_ANY_MDS && frag.ndist > 0) {
602                                 u8 r;
603
604                                 /* choose a random replica */
605                                 get_random_bytes(&r, 1);
606                                 r %= frag.ndist;
607                                 mds = frag.dist[r];
608                                 dout("choose_mds %p %llx.%llx "
609                                      "frag %u mds%d (%d/%d)\n",
610                                      inode, ceph_vinop(inode),
611                                      frag.frag, frag.mds,
612                                      (int)r, frag.ndist);
613                                 return mds;
614                         }
615
616                         /* since this file/dir wasn't known to be
617                          * replicated, then we want to look for the
618                          * authoritative mds. */
619                         mode = USE_AUTH_MDS;
620                         if (frag.mds >= 0) {
621                                 /* choose auth mds */
622                                 mds = frag.mds;
623                                 dout("choose_mds %p %llx.%llx "
624                                      "frag %u mds%d (auth)\n",
625                                      inode, ceph_vinop(inode), frag.frag, mds);
626                                 return mds;
627                         }
628                 }
629         }
630
631         spin_lock(&inode->i_lock);
632         cap = NULL;
633         if (mode == USE_AUTH_MDS)
634                 cap = ci->i_auth_cap;
635         if (!cap && !RB_EMPTY_ROOT(&ci->i_caps))
636                 cap = rb_entry(rb_first(&ci->i_caps), struct ceph_cap, ci_node);
637         if (!cap) {
638                 spin_unlock(&inode->i_lock);
639                 goto random;
640         }
641         mds = cap->session->s_mds;
642         dout("choose_mds %p %llx.%llx mds%d (%scap %p)\n",
643              inode, ceph_vinop(inode), mds,
644              cap == ci->i_auth_cap ? "auth " : "", cap);
645         spin_unlock(&inode->i_lock);
646         return mds;
647
648 random:
649         mds = ceph_mdsmap_get_random_mds(mdsc->mdsmap);
650         dout("choose_mds chose random mds%d\n", mds);
651         return mds;
652 }
653
654
655 /*
656  * session messages
657  */
658 static struct ceph_msg *create_session_msg(u32 op, u64 seq)
659 {
660         struct ceph_msg *msg;
661         struct ceph_mds_session_head *h;
662
663         msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h), 0, 0, NULL);
664         if (IS_ERR(msg)) {
665                 pr_err("create_session_msg ENOMEM creating msg\n");
666                 return ERR_PTR(PTR_ERR(msg));
667         }
668         h = msg->front.iov_base;
669         h->op = cpu_to_le32(op);
670         h->seq = cpu_to_le64(seq);
671         return msg;
672 }
673
674 /*
675  * send session open request.
676  *
677  * called under mdsc->mutex
678  */
679 static int __open_session(struct ceph_mds_client *mdsc,
680                           struct ceph_mds_session *session)
681 {
682         struct ceph_msg *msg;
683         int mstate;
684         int mds = session->s_mds;
685         int err = 0;
686
687         /* wait for mds to go active? */
688         mstate = ceph_mdsmap_get_state(mdsc->mdsmap, mds);
689         dout("open_session to mds%d (%s)\n", mds,
690              ceph_mds_state_name(mstate));
691         session->s_state = CEPH_MDS_SESSION_OPENING;
692         session->s_renew_requested = jiffies;
693
694         /* send connect message */
695         msg = create_session_msg(CEPH_SESSION_REQUEST_OPEN, session->s_seq);
696         if (IS_ERR(msg)) {
697                 err = PTR_ERR(msg);
698                 goto out;
699         }
700         ceph_con_send(&session->s_con, msg);
701
702 out:
703         return 0;
704 }
705
706 /*
707  * session caps
708  */
709
710 /*
711  * Free preallocated cap messages assigned to this session
712  */
713 static void cleanup_cap_releases(struct ceph_mds_session *session)
714 {
715         struct ceph_msg *msg;
716
717         spin_lock(&session->s_cap_lock);
718         while (!list_empty(&session->s_cap_releases)) {
719                 msg = list_first_entry(&session->s_cap_releases,
720                                        struct ceph_msg, list_head);
721                 list_del_init(&msg->list_head);
722                 ceph_msg_put(msg);
723         }
724         while (!list_empty(&session->s_cap_releases_done)) {
725                 msg = list_first_entry(&session->s_cap_releases_done,
726                                        struct ceph_msg, list_head);
727                 list_del_init(&msg->list_head);
728                 ceph_msg_put(msg);
729         }
730         spin_unlock(&session->s_cap_lock);
731 }
732
733 /*
734  * Helper to safely iterate over all caps associated with a session.
735  *
736  * caller must hold session s_mutex
737  */
738 static int iterate_session_caps(struct ceph_mds_session *session,
739                                  int (*cb)(struct inode *, struct ceph_cap *,
740                                             void *), void *arg)
741 {
742         struct list_head *p;
743         struct ceph_cap *cap;
744         struct inode *inode, *last_inode = NULL;
745         struct ceph_cap *old_cap = NULL;
746         int ret;
747
748         dout("iterate_session_caps %p mds%d\n", session, session->s_mds);
749         spin_lock(&session->s_cap_lock);
750         p = session->s_caps.next;
751         while (p != &session->s_caps) {
752                 cap = list_entry(p, struct ceph_cap, session_caps);
753                 inode = igrab(&cap->ci->vfs_inode);
754                 if (!inode) {
755                         p = p->next;
756                         continue;
757                 }
758                 session->s_cap_iterator = cap;
759                 spin_unlock(&session->s_cap_lock);
760
761                 if (last_inode) {
762                         iput(last_inode);
763                         last_inode = NULL;
764                 }
765                 if (old_cap) {
766                         ceph_put_cap(old_cap);
767                         old_cap = NULL;
768                 }
769
770                 ret = cb(inode, cap, arg);
771                 last_inode = inode;
772
773                 spin_lock(&session->s_cap_lock);
774                 p = p->next;
775                 if (cap->ci == NULL) {
776                         dout("iterate_session_caps  finishing cap %p removal\n",
777                              cap);
778                         BUG_ON(cap->session != session);
779                         list_del_init(&cap->session_caps);
780                         session->s_nr_caps--;
781                         cap->session = NULL;
782                         old_cap = cap;  /* put_cap it w/o locks held */
783                 }
784                 if (ret < 0)
785                         goto out;
786         }
787         ret = 0;
788 out:
789         session->s_cap_iterator = NULL;
790         spin_unlock(&session->s_cap_lock);
791
792         if (last_inode)
793                 iput(last_inode);
794         if (old_cap)
795                 ceph_put_cap(old_cap);
796
797         return ret;
798 }
799
800 static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
801                                    void *arg)
802 {
803         struct ceph_inode_info *ci = ceph_inode(inode);
804         dout("removing cap %p, ci is %p, inode is %p\n",
805              cap, ci, &ci->vfs_inode);
806         ceph_remove_cap(cap);
807         return 0;
808 }
809
810 /*
811  * caller must hold session s_mutex
812  */
813 static void remove_session_caps(struct ceph_mds_session *session)
814 {
815         dout("remove_session_caps on %p\n", session);
816         iterate_session_caps(session, remove_session_caps_cb, NULL);
817         BUG_ON(session->s_nr_caps > 0);
818         cleanup_cap_releases(session);
819 }
820
821 /*
822  * wake up any threads waiting on this session's caps.  if the cap is
823  * old (didn't get renewed on the client reconnect), remove it now.
824  *
825  * caller must hold s_mutex.
826  */
827 static int wake_up_session_cb(struct inode *inode, struct ceph_cap *cap,
828                               void *arg)
829 {
830         struct ceph_inode_info *ci = ceph_inode(inode);
831
832         wake_up(&ci->i_cap_wq);
833         if (arg) {
834                 spin_lock(&inode->i_lock);
835                 ci->i_wanted_max_size = 0;
836                 ci->i_requested_max_size = 0;
837                 spin_unlock(&inode->i_lock);
838         }
839         return 0;
840 }
841
842 static void wake_up_session_caps(struct ceph_mds_session *session,
843                                  int reconnect)
844 {
845         dout("wake_up_session_caps %p mds%d\n", session, session->s_mds);
846         iterate_session_caps(session, wake_up_session_cb,
847                              (void *)(unsigned long)reconnect);
848 }
849
850 /*
851  * Send periodic message to MDS renewing all currently held caps.  The
852  * ack will reset the expiration for all caps from this session.
853  *
854  * caller holds s_mutex
855  */
856 static int send_renew_caps(struct ceph_mds_client *mdsc,
857                            struct ceph_mds_session *session)
858 {
859         struct ceph_msg *msg;
860         int state;
861
862         if (time_after_eq(jiffies, session->s_cap_ttl) &&
863             time_after_eq(session->s_cap_ttl, session->s_renew_requested))
864                 pr_info("mds%d caps stale\n", session->s_mds);
865
866         /* do not try to renew caps until a recovering mds has reconnected
867          * with its clients. */
868         state = ceph_mdsmap_get_state(mdsc->mdsmap, session->s_mds);
869         if (state < CEPH_MDS_STATE_RECONNECT) {
870                 dout("send_renew_caps ignoring mds%d (%s)\n",
871                      session->s_mds, ceph_mds_state_name(state));
872                 return 0;
873         }
874
875         dout("send_renew_caps to mds%d (%s)\n", session->s_mds,
876                 ceph_mds_state_name(state));
877         session->s_renew_requested = jiffies;
878         msg = create_session_msg(CEPH_SESSION_REQUEST_RENEWCAPS,
879                                  ++session->s_renew_seq);
880         if (IS_ERR(msg))
881                 return PTR_ERR(msg);
882         ceph_con_send(&session->s_con, msg);
883         return 0;
884 }
885
886 /*
887  * Note new cap ttl, and any transition from stale -> not stale (fresh?).
888  *
889  * Called under session->s_mutex
890  */
891 static void renewed_caps(struct ceph_mds_client *mdsc,
892                          struct ceph_mds_session *session, int is_renew)
893 {
894         int was_stale;
895         int wake = 0;
896
897         spin_lock(&session->s_cap_lock);
898         was_stale = is_renew && (session->s_cap_ttl == 0 ||
899                                  time_after_eq(jiffies, session->s_cap_ttl));
900
901         session->s_cap_ttl = session->s_renew_requested +
902                 mdsc->mdsmap->m_session_timeout*HZ;
903
904         if (was_stale) {
905                 if (time_before(jiffies, session->s_cap_ttl)) {
906                         pr_info("mds%d caps renewed\n", session->s_mds);
907                         wake = 1;
908                 } else {
909                         pr_info("mds%d caps still stale\n", session->s_mds);
910                 }
911         }
912         dout("renewed_caps mds%d ttl now %lu, was %s, now %s\n",
913              session->s_mds, session->s_cap_ttl, was_stale ? "stale" : "fresh",
914              time_before(jiffies, session->s_cap_ttl) ? "stale" : "fresh");
915         spin_unlock(&session->s_cap_lock);
916
917         if (wake)
918                 wake_up_session_caps(session, 0);
919 }
920
921 /*
922  * send a session close request
923  */
924 static int request_close_session(struct ceph_mds_client *mdsc,
925                                  struct ceph_mds_session *session)
926 {
927         struct ceph_msg *msg;
928         int err = 0;
929
930         dout("request_close_session mds%d state %s seq %lld\n",
931              session->s_mds, session_state_name(session->s_state),
932              session->s_seq);
933         msg = create_session_msg(CEPH_SESSION_REQUEST_CLOSE, session->s_seq);
934         if (IS_ERR(msg))
935                 err = PTR_ERR(msg);
936         else
937                 ceph_con_send(&session->s_con, msg);
938         return err;
939 }
940
941 /*
942  * Called with s_mutex held.
943  */
944 static int __close_session(struct ceph_mds_client *mdsc,
945                          struct ceph_mds_session *session)
946 {
947         if (session->s_state >= CEPH_MDS_SESSION_CLOSING)
948                 return 0;
949         session->s_state = CEPH_MDS_SESSION_CLOSING;
950         return request_close_session(mdsc, session);
951 }
952
953 /*
954  * Trim old(er) caps.
955  *
956  * Because we can't cache an inode without one or more caps, we do
957  * this indirectly: if a cap is unused, we prune its aliases, at which
958  * point the inode will hopefully get dropped to.
959  *
960  * Yes, this is a bit sloppy.  Our only real goal here is to respond to
961  * memory pressure from the MDS, though, so it needn't be perfect.
962  */
963 static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
964 {
965         struct ceph_mds_session *session = arg;
966         struct ceph_inode_info *ci = ceph_inode(inode);
967         int used, oissued, mine;
968
969         if (session->s_trim_caps <= 0)
970                 return -1;
971
972         spin_lock(&inode->i_lock);
973         mine = cap->issued | cap->implemented;
974         used = __ceph_caps_used(ci);
975         oissued = __ceph_caps_issued_other(ci, cap);
976
977         dout("trim_caps_cb %p cap %p mine %s oissued %s used %s\n",
978              inode, cap, ceph_cap_string(mine), ceph_cap_string(oissued),
979              ceph_cap_string(used));
980         if (ci->i_dirty_caps)
981                 goto out;   /* dirty caps */
982         if ((used & ~oissued) & mine)
983                 goto out;   /* we need these caps */
984
985         session->s_trim_caps--;
986         if (oissued) {
987                 /* we aren't the only cap.. just remove us */
988                 __ceph_remove_cap(cap);
989         } else {
990                 /* try to drop referring dentries */
991                 spin_unlock(&inode->i_lock);
992                 d_prune_aliases(inode);
993                 dout("trim_caps_cb %p cap %p  pruned, count now %d\n",
994                      inode, cap, atomic_read(&inode->i_count));
995                 return 0;
996         }
997
998 out:
999         spin_unlock(&inode->i_lock);
1000         return 0;
1001 }
1002
1003 /*
1004  * Trim session cap count down to some max number.
1005  */
1006 static int trim_caps(struct ceph_mds_client *mdsc,
1007                      struct ceph_mds_session *session,
1008                      int max_caps)
1009 {
1010         int trim_caps = session->s_nr_caps - max_caps;
1011
1012         dout("trim_caps mds%d start: %d / %d, trim %d\n",
1013              session->s_mds, session->s_nr_caps, max_caps, trim_caps);
1014         if (trim_caps > 0) {
1015                 session->s_trim_caps = trim_caps;
1016                 iterate_session_caps(session, trim_caps_cb, session);
1017                 dout("trim_caps mds%d done: %d / %d, trimmed %d\n",
1018                      session->s_mds, session->s_nr_caps, max_caps,
1019                         trim_caps - session->s_trim_caps);
1020                 session->s_trim_caps = 0;
1021         }
1022         return 0;
1023 }
1024
1025 /*
1026  * Allocate cap_release messages.  If there is a partially full message
1027  * in the queue, try to allocate enough to cover it's remainder, so that
1028  * we can send it immediately.
1029  *
1030  * Called under s_mutex.
1031  */
1032 static int add_cap_releases(struct ceph_mds_client *mdsc,
1033                             struct ceph_mds_session *session,
1034                             int extra)
1035 {
1036         struct ceph_msg *msg;
1037         struct ceph_mds_cap_release *head;
1038         int err = -ENOMEM;
1039
1040         if (extra < 0)
1041                 extra = mdsc->client->mount_args->cap_release_safety;
1042
1043         spin_lock(&session->s_cap_lock);
1044
1045         if (!list_empty(&session->s_cap_releases)) {
1046                 msg = list_first_entry(&session->s_cap_releases,
1047                                        struct ceph_msg,
1048                                  list_head);
1049                 head = msg->front.iov_base;
1050                 extra += CEPH_CAPS_PER_RELEASE - le32_to_cpu(head->num);
1051         }
1052
1053         while (session->s_num_cap_releases < session->s_nr_caps + extra) {
1054                 spin_unlock(&session->s_cap_lock);
1055                 msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPRELEASE, PAGE_CACHE_SIZE,
1056                                    0, 0, NULL);
1057                 if (!msg)
1058                         goto out_unlocked;
1059                 dout("add_cap_releases %p msg %p now %d\n", session, msg,
1060                      (int)msg->front.iov_len);
1061                 head = msg->front.iov_base;
1062                 head->num = cpu_to_le32(0);
1063                 msg->front.iov_len = sizeof(*head);
1064                 spin_lock(&session->s_cap_lock);
1065                 list_add(&msg->list_head, &session->s_cap_releases);
1066                 session->s_num_cap_releases += CEPH_CAPS_PER_RELEASE;
1067         }
1068
1069         if (!list_empty(&session->s_cap_releases)) {
1070                 msg = list_first_entry(&session->s_cap_releases,
1071                                        struct ceph_msg,
1072                                        list_head);
1073                 head = msg->front.iov_base;
1074                 if (head->num) {
1075                         dout(" queueing non-full %p (%d)\n", msg,
1076                              le32_to_cpu(head->num));
1077                         list_move_tail(&msg->list_head,
1078                                       &session->s_cap_releases_done);
1079                         session->s_num_cap_releases -=
1080                                 CEPH_CAPS_PER_RELEASE - le32_to_cpu(head->num);
1081                 }
1082         }
1083         err = 0;
1084         spin_unlock(&session->s_cap_lock);
1085 out_unlocked:
1086         return err;
1087 }
1088
1089 /*
1090  * flush all dirty inode data to disk.
1091  *
1092  * returns true if we've flushed through want_flush_seq
1093  */
1094 static int check_cap_flush(struct ceph_mds_client *mdsc, u64 want_flush_seq)
1095 {
1096         int mds, ret = 1;
1097
1098         dout("check_cap_flush want %lld\n", want_flush_seq);
1099         mutex_lock(&mdsc->mutex);
1100         for (mds = 0; ret && mds < mdsc->max_sessions; mds++) {
1101                 struct ceph_mds_session *session = mdsc->sessions[mds];
1102
1103                 if (!session)
1104                         continue;
1105                 get_session(session);
1106                 mutex_unlock(&mdsc->mutex);
1107
1108                 mutex_lock(&session->s_mutex);
1109                 if (!list_empty(&session->s_cap_flushing)) {
1110                         struct ceph_inode_info *ci =
1111                                 list_entry(session->s_cap_flushing.next,
1112                                            struct ceph_inode_info,
1113                                            i_flushing_item);
1114                         struct inode *inode = &ci->vfs_inode;
1115
1116                         spin_lock(&inode->i_lock);
1117                         if (ci->i_cap_flush_seq <= want_flush_seq) {
1118                                 dout("check_cap_flush still flushing %p "
1119                                      "seq %lld <= %lld to mds%d\n", inode,
1120                                      ci->i_cap_flush_seq, want_flush_seq,
1121                                      session->s_mds);
1122                                 ret = 0;
1123                         }
1124                         spin_unlock(&inode->i_lock);
1125                 }
1126                 mutex_unlock(&session->s_mutex);
1127                 ceph_put_mds_session(session);
1128
1129                 if (!ret)
1130                         return ret;
1131                 mutex_lock(&mdsc->mutex);
1132         }
1133
1134         mutex_unlock(&mdsc->mutex);
1135         dout("check_cap_flush ok, flushed thru %lld\n", want_flush_seq);
1136         return ret;
1137 }
1138
1139 /*
1140  * called under s_mutex
1141  */
1142 static void send_cap_releases(struct ceph_mds_client *mdsc,
1143                        struct ceph_mds_session *session)
1144 {
1145         struct ceph_msg *msg;
1146
1147         dout("send_cap_releases mds%d\n", session->s_mds);
1148         while (1) {
1149                 spin_lock(&session->s_cap_lock);
1150                 if (list_empty(&session->s_cap_releases_done))
1151                         break;
1152                 msg = list_first_entry(&session->s_cap_releases_done,
1153                                  struct ceph_msg, list_head);
1154                 list_del_init(&msg->list_head);
1155                 spin_unlock(&session->s_cap_lock);
1156                 msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
1157                 dout("send_cap_releases mds%d %p\n", session->s_mds, msg);
1158                 ceph_con_send(&session->s_con, msg);
1159         }
1160         spin_unlock(&session->s_cap_lock);
1161 }
1162
1163 /*
1164  * requests
1165  */
1166
1167 /*
1168  * Create an mds request.
1169  */
1170 struct ceph_mds_request *
1171 ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode)
1172 {
1173         struct ceph_mds_request *req = kzalloc(sizeof(*req), GFP_NOFS);
1174
1175         if (!req)
1176                 return ERR_PTR(-ENOMEM);
1177
1178         req->r_started = jiffies;
1179         req->r_resend_mds = -1;
1180         INIT_LIST_HEAD(&req->r_unsafe_dir_item);
1181         req->r_fmode = -1;
1182         kref_init(&req->r_kref);
1183         INIT_LIST_HEAD(&req->r_wait);
1184         init_completion(&req->r_completion);
1185         init_completion(&req->r_safe_completion);
1186         INIT_LIST_HEAD(&req->r_unsafe_item);
1187
1188         req->r_op = op;
1189         req->r_direct_mode = mode;
1190         return req;
1191 }
1192
1193 /*
1194  * return oldest (lowest) request, tid in request tree, 0 if none.
1195  *
1196  * called under mdsc->mutex.
1197  */
1198 static struct ceph_mds_request *__get_oldest_req(struct ceph_mds_client *mdsc)
1199 {
1200         if (RB_EMPTY_ROOT(&mdsc->request_tree))
1201                 return NULL;
1202         return rb_entry(rb_first(&mdsc->request_tree),
1203                         struct ceph_mds_request, r_node);
1204 }
1205
1206 static u64 __get_oldest_tid(struct ceph_mds_client *mdsc)
1207 {
1208         struct ceph_mds_request *req = __get_oldest_req(mdsc);
1209
1210         if (req)
1211                 return req->r_tid;
1212         return 0;
1213 }
1214
1215 /*
1216  * Build a dentry's path.  Allocate on heap; caller must kfree.  Based
1217  * on build_path_from_dentry in fs/cifs/dir.c.
1218  *
1219  * If @stop_on_nosnap, generate path relative to the first non-snapped
1220  * inode.
1221  *
1222  * Encode hidden .snap dirs as a double /, i.e.
1223  *   foo/.snap/bar -> foo//bar
1224  */
1225 char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *base,
1226                            int stop_on_nosnap)
1227 {
1228         struct dentry *temp;
1229         char *path;
1230         int len, pos;
1231
1232         if (dentry == NULL)
1233                 return ERR_PTR(-EINVAL);
1234
1235 retry:
1236         len = 0;
1237         for (temp = dentry; !IS_ROOT(temp);) {
1238                 struct inode *inode = temp->d_inode;
1239                 if (inode && ceph_snap(inode) == CEPH_SNAPDIR)
1240                         len++;  /* slash only */
1241                 else if (stop_on_nosnap && inode &&
1242                          ceph_snap(inode) == CEPH_NOSNAP)
1243                         break;
1244                 else
1245                         len += 1 + temp->d_name.len;
1246                 temp = temp->d_parent;
1247                 if (temp == NULL) {
1248                         pr_err("build_path_dentry corrupt dentry %p\n", dentry);
1249                         return ERR_PTR(-EINVAL);
1250                 }
1251         }
1252         if (len)
1253                 len--;  /* no leading '/' */
1254
1255         path = kmalloc(len+1, GFP_NOFS);
1256         if (path == NULL)
1257                 return ERR_PTR(-ENOMEM);
1258         pos = len;
1259         path[pos] = 0;  /* trailing null */
1260         for (temp = dentry; !IS_ROOT(temp) && pos != 0; ) {
1261                 struct inode *inode = temp->d_inode;
1262
1263                 if (inode && ceph_snap(inode) == CEPH_SNAPDIR) {
1264                         dout("build_path_dentry path+%d: %p SNAPDIR\n",
1265                              pos, temp);
1266                 } else if (stop_on_nosnap && inode &&
1267                            ceph_snap(inode) == CEPH_NOSNAP) {
1268                         break;
1269                 } else {
1270                         pos -= temp->d_name.len;
1271                         if (pos < 0)
1272                                 break;
1273                         strncpy(path + pos, temp->d_name.name,
1274                                 temp->d_name.len);
1275                         dout("build_path_dentry path+%d: %p '%.*s'\n",
1276                              pos, temp, temp->d_name.len, path + pos);
1277                 }
1278                 if (pos)
1279                         path[--pos] = '/';
1280                 temp = temp->d_parent;
1281                 if (temp == NULL) {
1282                         pr_err("build_path_dentry corrupt dentry\n");
1283                         kfree(path);
1284                         return ERR_PTR(-EINVAL);
1285                 }
1286         }
1287         if (pos != 0) {
1288                 pr_err("build_path_dentry did not end path lookup where "
1289                        "expected, namelen is %d, pos is %d\n", len, pos);
1290                 /* presumably this is only possible if racing with a
1291                    rename of one of the parent directories (we can not
1292                    lock the dentries above us to prevent this, but
1293                    retrying should be harmless) */
1294                 kfree(path);
1295                 goto retry;
1296         }
1297
1298         *base = ceph_ino(temp->d_inode);
1299         *plen = len;
1300         dout("build_path_dentry on %p %d built %llx '%.*s'\n",
1301              dentry, atomic_read(&dentry->d_count), *base, len, path);
1302         return path;
1303 }
1304
1305 static int build_dentry_path(struct dentry *dentry,
1306                              const char **ppath, int *ppathlen, u64 *pino,
1307                              int *pfreepath)
1308 {
1309         char *path;
1310
1311         if (ceph_snap(dentry->d_parent->d_inode) == CEPH_NOSNAP) {
1312                 *pino = ceph_ino(dentry->d_parent->d_inode);
1313                 *ppath = dentry->d_name.name;
1314                 *ppathlen = dentry->d_name.len;
1315                 return 0;
1316         }
1317         path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
1318         if (IS_ERR(path))
1319                 return PTR_ERR(path);
1320         *ppath = path;
1321         *pfreepath = 1;
1322         return 0;
1323 }
1324
1325 static int build_inode_path(struct inode *inode,
1326                             const char **ppath, int *ppathlen, u64 *pino,
1327                             int *pfreepath)
1328 {
1329         struct dentry *dentry;
1330         char *path;
1331
1332         if (ceph_snap(inode) == CEPH_NOSNAP) {
1333                 *pino = ceph_ino(inode);
1334                 *ppathlen = 0;
1335                 return 0;
1336         }
1337         dentry = d_find_alias(inode);
1338         path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
1339         dput(dentry);
1340         if (IS_ERR(path))
1341                 return PTR_ERR(path);
1342         *ppath = path;
1343         *pfreepath = 1;
1344         return 0;
1345 }
1346
1347 /*
1348  * request arguments may be specified via an inode *, a dentry *, or
1349  * an explicit ino+path.
1350  */
1351 static int set_request_path_attr(struct inode *rinode, struct dentry *rdentry,
1352                                   const char *rpath, u64 rino,
1353                                   const char **ppath, int *pathlen,
1354                                   u64 *ino, int *freepath)
1355 {
1356         int r = 0;
1357
1358         if (rinode) {
1359                 r = build_inode_path(rinode, ppath, pathlen, ino, freepath);
1360                 dout(" inode %p %llx.%llx\n", rinode, ceph_ino(rinode),
1361                      ceph_snap(rinode));
1362         } else if (rdentry) {
1363                 r = build_dentry_path(rdentry, ppath, pathlen, ino, freepath);
1364                 dout(" dentry %p %llx/%.*s\n", rdentry, *ino, *pathlen,
1365                      *ppath);
1366         } else if (rpath) {
1367                 *ino = rino;
1368                 *ppath = rpath;
1369                 *pathlen = strlen(rpath);
1370                 dout(" path %.*s\n", *pathlen, rpath);
1371         }
1372
1373         return r;
1374 }
1375
1376 /*
1377  * called under mdsc->mutex
1378  */
1379 static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
1380                                                struct ceph_mds_request *req,
1381                                                int mds)
1382 {
1383         struct ceph_msg *msg;
1384         struct ceph_mds_request_head *head;
1385         const char *path1 = NULL;
1386         const char *path2 = NULL;
1387         u64 ino1 = 0, ino2 = 0;
1388         int pathlen1 = 0, pathlen2 = 0;
1389         int freepath1 = 0, freepath2 = 0;
1390         int len;
1391         u16 releases;
1392         void *p, *end;
1393         int ret;
1394
1395         ret = set_request_path_attr(req->r_inode, req->r_dentry,
1396                               req->r_path1, req->r_ino1.ino,
1397                               &path1, &pathlen1, &ino1, &freepath1);
1398         if (ret < 0) {
1399                 msg = ERR_PTR(ret);
1400                 goto out;
1401         }
1402
1403         ret = set_request_path_attr(NULL, req->r_old_dentry,
1404                               req->r_path2, req->r_ino2.ino,
1405                               &path2, &pathlen2, &ino2, &freepath2);
1406         if (ret < 0) {
1407                 msg = ERR_PTR(ret);
1408                 goto out_free1;
1409         }
1410
1411         len = sizeof(*head) +
1412                 pathlen1 + pathlen2 + 2*(1 + sizeof(u32) + sizeof(u64));
1413
1414         /* calculate (max) length for cap releases */
1415         len += sizeof(struct ceph_mds_request_release) *
1416                 (!!req->r_inode_drop + !!req->r_dentry_drop +
1417                  !!req->r_old_inode_drop + !!req->r_old_dentry_drop);
1418         if (req->r_dentry_drop)
1419                 len += req->r_dentry->d_name.len;
1420         if (req->r_old_dentry_drop)
1421                 len += req->r_old_dentry->d_name.len;
1422
1423         msg = ceph_msg_new(CEPH_MSG_CLIENT_REQUEST, len, 0, 0, NULL);
1424         if (IS_ERR(msg))
1425                 goto out_free2;
1426
1427         msg->hdr.tid = cpu_to_le64(req->r_tid);
1428
1429         head = msg->front.iov_base;
1430         p = msg->front.iov_base + sizeof(*head);
1431         end = msg->front.iov_base + msg->front.iov_len;
1432
1433         head->mdsmap_epoch = cpu_to_le32(mdsc->mdsmap->m_epoch);
1434         head->op = cpu_to_le32(req->r_op);
1435         head->caller_uid = cpu_to_le32(current_fsuid());
1436         head->caller_gid = cpu_to_le32(current_fsgid());
1437         head->args = req->r_args;
1438
1439         ceph_encode_filepath(&p, end, ino1, path1);
1440         ceph_encode_filepath(&p, end, ino2, path2);
1441
1442         /* cap releases */
1443         releases = 0;
1444         if (req->r_inode_drop)
1445                 releases += ceph_encode_inode_release(&p,
1446                       req->r_inode ? req->r_inode : req->r_dentry->d_inode,
1447                       mds, req->r_inode_drop, req->r_inode_unless, 0);
1448         if (req->r_dentry_drop)
1449                 releases += ceph_encode_dentry_release(&p, req->r_dentry,
1450                        mds, req->r_dentry_drop, req->r_dentry_unless);
1451         if (req->r_old_dentry_drop)
1452                 releases += ceph_encode_dentry_release(&p, req->r_old_dentry,
1453                        mds, req->r_old_dentry_drop, req->r_old_dentry_unless);
1454         if (req->r_old_inode_drop)
1455                 releases += ceph_encode_inode_release(&p,
1456                       req->r_old_dentry->d_inode,
1457                       mds, req->r_old_inode_drop, req->r_old_inode_unless, 0);
1458         head->num_releases = cpu_to_le16(releases);
1459
1460         BUG_ON(p > end);
1461         msg->front.iov_len = p - msg->front.iov_base;
1462         msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
1463
1464         msg->pages = req->r_pages;
1465         msg->nr_pages = req->r_num_pages;
1466         msg->hdr.data_len = cpu_to_le32(req->r_data_len);
1467         msg->hdr.data_off = cpu_to_le16(0);
1468
1469 out_free2:
1470         if (freepath2)
1471                 kfree((char *)path2);
1472 out_free1:
1473         if (freepath1)
1474                 kfree((char *)path1);
1475 out:
1476         return msg;
1477 }
1478
1479 /*
1480  * called under mdsc->mutex if error, under no mutex if
1481  * success.
1482  */
1483 static void complete_request(struct ceph_mds_client *mdsc,
1484                              struct ceph_mds_request *req)
1485 {
1486         if (req->r_callback)
1487                 req->r_callback(mdsc, req);
1488         else
1489                 complete(&req->r_completion);
1490 }
1491
1492 /*
1493  * called under mdsc->mutex
1494  */
1495 static int __prepare_send_request(struct ceph_mds_client *mdsc,
1496                                   struct ceph_mds_request *req,
1497                                   int mds)
1498 {
1499         struct ceph_mds_request_head *rhead;
1500         struct ceph_msg *msg;
1501         int flags = 0;
1502
1503         req->r_mds = mds;
1504         req->r_attempts++;
1505         dout("prepare_send_request %p tid %lld %s (attempt %d)\n", req,
1506              req->r_tid, ceph_mds_op_name(req->r_op), req->r_attempts);
1507
1508         if (req->r_request) {
1509                 ceph_msg_put(req->r_request);
1510                 req->r_request = NULL;
1511         }
1512         msg = create_request_message(mdsc, req, mds);
1513         if (IS_ERR(msg)) {
1514                 req->r_reply = ERR_PTR(PTR_ERR(msg));
1515                 complete_request(mdsc, req);
1516                 return -PTR_ERR(msg);
1517         }
1518         req->r_request = msg;
1519
1520         rhead = msg->front.iov_base;
1521         rhead->oldest_client_tid = cpu_to_le64(__get_oldest_tid(mdsc));
1522         if (req->r_got_unsafe)
1523                 flags |= CEPH_MDS_FLAG_REPLAY;
1524         if (req->r_locked_dir)
1525                 flags |= CEPH_MDS_FLAG_WANT_DENTRY;
1526         rhead->flags = cpu_to_le32(flags);
1527         rhead->num_fwd = req->r_num_fwd;
1528         rhead->num_retry = req->r_attempts - 1;
1529
1530         dout(" r_locked_dir = %p\n", req->r_locked_dir);
1531
1532         if (req->r_target_inode && req->r_got_unsafe)
1533                 rhead->ino = cpu_to_le64(ceph_ino(req->r_target_inode));
1534         else
1535                 rhead->ino = 0;
1536         return 0;
1537 }
1538
1539 /*
1540  * send request, or put it on the appropriate wait list.
1541  */
1542 static int __do_request(struct ceph_mds_client *mdsc,
1543                         struct ceph_mds_request *req)
1544 {
1545         struct ceph_mds_session *session = NULL;
1546         int mds = -1;
1547         int err = -EAGAIN;
1548
1549         if (req->r_reply)
1550                 goto out;
1551
1552         if (req->r_timeout &&
1553             time_after_eq(jiffies, req->r_started + req->r_timeout)) {
1554                 dout("do_request timed out\n");
1555                 err = -EIO;
1556                 goto finish;
1557         }
1558
1559         mds = __choose_mds(mdsc, req);
1560         if (mds < 0 ||
1561             ceph_mdsmap_get_state(mdsc->mdsmap, mds) < CEPH_MDS_STATE_ACTIVE) {
1562                 dout("do_request no mds or not active, waiting for map\n");
1563                 list_add(&req->r_wait, &mdsc->waiting_for_map);
1564                 goto out;
1565         }
1566
1567         /* get, open session */
1568         session = __ceph_lookup_mds_session(mdsc, mds);
1569         if (!session)
1570                 session = register_session(mdsc, mds);
1571         dout("do_request mds%d session %p state %s\n", mds, session,
1572              session_state_name(session->s_state));
1573         if (session->s_state != CEPH_MDS_SESSION_OPEN &&
1574             session->s_state != CEPH_MDS_SESSION_HUNG) {
1575                 if (session->s_state == CEPH_MDS_SESSION_NEW ||
1576                     session->s_state == CEPH_MDS_SESSION_CLOSING)
1577                         __open_session(mdsc, session);
1578                 list_add(&req->r_wait, &session->s_waiting);
1579                 goto out_session;
1580         }
1581
1582         /* send request */
1583         req->r_session = get_session(session);
1584         req->r_resend_mds = -1;   /* forget any previous mds hint */
1585
1586         if (req->r_request_started == 0)   /* note request start time */
1587                 req->r_request_started = jiffies;
1588
1589         err = __prepare_send_request(mdsc, req, mds);
1590         if (!err) {
1591                 ceph_msg_get(req->r_request);
1592                 ceph_con_send(&session->s_con, req->r_request);
1593         }
1594
1595 out_session:
1596         ceph_put_mds_session(session);
1597 out:
1598         return err;
1599
1600 finish:
1601         req->r_reply = ERR_PTR(err);
1602         complete_request(mdsc, req);
1603         goto out;
1604 }
1605
1606 /*
1607  * called under mdsc->mutex
1608  */
1609 static void __wake_requests(struct ceph_mds_client *mdsc,
1610                             struct list_head *head)
1611 {
1612         struct ceph_mds_request *req, *nreq;
1613
1614         list_for_each_entry_safe(req, nreq, head, r_wait) {
1615                 list_del_init(&req->r_wait);
1616                 __do_request(mdsc, req);
1617         }
1618 }
1619
1620 /*
1621  * Wake up threads with requests pending for @mds, so that they can
1622  * resubmit their requests to a possibly different mds.  If @all is set,
1623  * wake up if their requests has been forwarded to @mds, too.
1624  */
1625 static void kick_requests(struct ceph_mds_client *mdsc, int mds, int all)
1626 {
1627         struct ceph_mds_request *req;
1628         struct rb_node *p;
1629
1630         dout("kick_requests mds%d\n", mds);
1631         for (p = rb_first(&mdsc->request_tree); p; p = rb_next(p)) {
1632                 req = rb_entry(p, struct ceph_mds_request, r_node);
1633                 if (req->r_got_unsafe)
1634                         continue;
1635                 if (req->r_session &&
1636                     req->r_session->s_mds == mds) {
1637                         dout(" kicking tid %llu\n", req->r_tid);
1638                         put_request_session(req);
1639                         __do_request(mdsc, req);
1640                 }
1641         }
1642 }
1643
1644 void ceph_mdsc_submit_request(struct ceph_mds_client *mdsc,
1645                               struct ceph_mds_request *req)
1646 {
1647         dout("submit_request on %p\n", req);
1648         mutex_lock(&mdsc->mutex);
1649         __register_request(mdsc, req, NULL);
1650         __do_request(mdsc, req);
1651         mutex_unlock(&mdsc->mutex);
1652 }
1653
1654 /*
1655  * Synchrously perform an mds request.  Take care of all of the
1656  * session setup, forwarding, retry details.
1657  */
1658 int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
1659                          struct inode *dir,
1660                          struct ceph_mds_request *req)
1661 {
1662         int err;
1663
1664         dout("do_request on %p\n", req);
1665
1666         /* take CAP_PIN refs for r_inode, r_locked_dir, r_old_dentry */
1667         if (req->r_inode)
1668                 ceph_get_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
1669         if (req->r_locked_dir)
1670                 ceph_get_cap_refs(ceph_inode(req->r_locked_dir), CEPH_CAP_PIN);
1671         if (req->r_old_dentry)
1672                 ceph_get_cap_refs(
1673                         ceph_inode(req->r_old_dentry->d_parent->d_inode),
1674                         CEPH_CAP_PIN);
1675
1676         /* issue */
1677         mutex_lock(&mdsc->mutex);
1678         __register_request(mdsc, req, dir);
1679         __do_request(mdsc, req);
1680
1681         /* wait */
1682         if (!req->r_reply) {
1683                 mutex_unlock(&mdsc->mutex);
1684                 if (req->r_timeout) {
1685                         err = (long)wait_for_completion_interruptible_timeout(
1686                                 &req->r_completion, req->r_timeout);
1687                         if (err == 0)
1688                                 req->r_reply = ERR_PTR(-EIO);
1689                         else if (err < 0)
1690                                 req->r_reply = ERR_PTR(err);
1691                 } else {
1692                         err = wait_for_completion_interruptible(
1693                                 &req->r_completion);
1694                         if (err)
1695                                 req->r_reply = ERR_PTR(err);
1696                 }
1697                 mutex_lock(&mdsc->mutex);
1698         }
1699
1700         if (IS_ERR(req->r_reply)) {
1701                 err = PTR_ERR(req->r_reply);
1702                 req->r_reply = NULL;
1703
1704                 if (err == -ERESTARTSYS) {
1705                         /* aborted */
1706                         req->r_aborted = true;
1707
1708                         if (req->r_locked_dir &&
1709                             (req->r_op & CEPH_MDS_OP_WRITE)) {
1710                                 struct ceph_inode_info *ci =
1711                                         ceph_inode(req->r_locked_dir);
1712
1713                                 dout("aborted, clearing I_COMPLETE on %p\n", 
1714                                      req->r_locked_dir);
1715                                 spin_lock(&req->r_locked_dir->i_lock);
1716                                 ci->i_ceph_flags &= ~CEPH_I_COMPLETE;
1717                                 ci->i_release_count++;
1718                                 spin_unlock(&req->r_locked_dir->i_lock);
1719                         }
1720                 } else {
1721                         /* clean up this request */
1722                         __unregister_request(mdsc, req);
1723                         if (!list_empty(&req->r_unsafe_item))
1724                                 list_del_init(&req->r_unsafe_item);
1725                         complete(&req->r_safe_completion);
1726                 }
1727         } else if (req->r_err) {
1728                 err = req->r_err;
1729         } else {
1730                 err = le32_to_cpu(req->r_reply_info.head->result);
1731         }
1732         mutex_unlock(&mdsc->mutex);
1733
1734         dout("do_request %p done, result %d\n", req, err);
1735         return err;
1736 }
1737
1738 /*
1739  * Handle mds reply.
1740  *
1741  * We take the session mutex and parse and process the reply immediately.
1742  * This preserves the logical ordering of replies, capabilities, etc., sent
1743  * by the MDS as they are applied to our local cache.
1744  */
1745 static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
1746 {
1747         struct ceph_mds_client *mdsc = session->s_mdsc;
1748         struct ceph_mds_request *req;
1749         struct ceph_mds_reply_head *head = msg->front.iov_base;
1750         struct ceph_mds_reply_info_parsed *rinfo;  /* parsed reply info */
1751         u64 tid;
1752         int err, result;
1753         int mds = session->s_mds;
1754
1755         if (msg->front.iov_len < sizeof(*head)) {
1756                 pr_err("mdsc_handle_reply got corrupt (short) reply\n");
1757                 ceph_msg_dump(msg);
1758                 return;
1759         }
1760
1761         /* get request, session */
1762         tid = le64_to_cpu(msg->hdr.tid);
1763         mutex_lock(&mdsc->mutex);
1764         req = __lookup_request(mdsc, tid);
1765         if (!req) {
1766                 dout("handle_reply on unknown tid %llu\n", tid);
1767                 mutex_unlock(&mdsc->mutex);
1768                 return;
1769         }
1770         dout("handle_reply %p\n", req);
1771
1772         /* correct session? */
1773         if (!req->r_session && req->r_session != session) {
1774                 pr_err("mdsc_handle_reply got %llu on session mds%d"
1775                        " not mds%d\n", tid, session->s_mds,
1776                        req->r_session ? req->r_session->s_mds : -1);
1777                 mutex_unlock(&mdsc->mutex);
1778                 goto out;
1779         }
1780
1781         /* dup? */
1782         if ((req->r_got_unsafe && !head->safe) ||
1783             (req->r_got_safe && head->safe)) {
1784                 pr_warning("got a dup %s reply on %llu from mds%d\n",
1785                            head->safe ? "safe" : "unsafe", tid, mds);
1786                 mutex_unlock(&mdsc->mutex);
1787                 goto out;
1788         }
1789
1790         result = le32_to_cpu(head->result);
1791
1792         /*
1793          * Tolerate 2 consecutive ESTALEs from the same mds.
1794          * FIXME: we should be looking at the cap migrate_seq.
1795          */
1796         if (result == -ESTALE) {
1797                 req->r_direct_mode = USE_AUTH_MDS;
1798                 req->r_num_stale++;
1799                 if (req->r_num_stale <= 2) {
1800                         __do_request(mdsc, req);
1801                         mutex_unlock(&mdsc->mutex);
1802                         goto out;
1803                 }
1804         } else {
1805                 req->r_num_stale = 0;
1806         }
1807
1808         if (head->safe) {
1809                 req->r_got_safe = true;
1810                 __unregister_request(mdsc, req);
1811                 complete(&req->r_safe_completion);
1812
1813                 if (req->r_got_unsafe) {
1814                         /*
1815                          * We already handled the unsafe response, now do the
1816                          * cleanup.  No need to examine the response; the MDS
1817                          * doesn't include any result info in the safe
1818                          * response.  And even if it did, there is nothing
1819                          * useful we could do with a revised return value.
1820                          */
1821                         dout("got safe reply %llu, mds%d\n", tid, mds);
1822                         list_del_init(&req->r_unsafe_item);
1823
1824                         /* last unsafe request during umount? */
1825                         if (mdsc->stopping && !__get_oldest_req(mdsc))
1826                                 complete(&mdsc->safe_umount_waiters);
1827                         mutex_unlock(&mdsc->mutex);
1828                         goto out;
1829                 }
1830         }
1831
1832         BUG_ON(req->r_reply);
1833
1834         if (!head->safe) {
1835                 req->r_got_unsafe = true;
1836                 list_add_tail(&req->r_unsafe_item, &req->r_session->s_unsafe);
1837         }
1838
1839         dout("handle_reply tid %lld result %d\n", tid, result);
1840         rinfo = &req->r_reply_info;
1841         err = parse_reply_info(msg, rinfo);
1842         mutex_unlock(&mdsc->mutex);
1843
1844         mutex_lock(&session->s_mutex);
1845         if (err < 0) {
1846                 pr_err("mdsc_handle_reply got corrupt reply mds%d\n", mds);
1847                 ceph_msg_dump(msg);
1848                 goto out_err;
1849         }
1850
1851         /* snap trace */
1852         if (rinfo->snapblob_len) {
1853                 down_write(&mdsc->snap_rwsem);
1854                 ceph_update_snap_trace(mdsc, rinfo->snapblob,
1855                                rinfo->snapblob + rinfo->snapblob_len,
1856                                le32_to_cpu(head->op) == CEPH_MDS_OP_RMSNAP);
1857                 downgrade_write(&mdsc->snap_rwsem);
1858         } else {
1859                 down_read(&mdsc->snap_rwsem);
1860         }
1861
1862         /* insert trace into our cache */
1863         err = ceph_fill_trace(mdsc->client->sb, req, req->r_session);
1864         if (err == 0) {
1865                 if (result == 0 && rinfo->dir_nr)
1866                         ceph_readdir_prepopulate(req, req->r_session);
1867                 ceph_unreserve_caps(&req->r_caps_reservation);
1868         }
1869
1870         up_read(&mdsc->snap_rwsem);
1871 out_err:
1872         if (err) {
1873                 req->r_err = err;
1874         } else {
1875                 req->r_reply = msg;
1876                 ceph_msg_get(msg);
1877         }
1878
1879         add_cap_releases(mdsc, req->r_session, -1);
1880         mutex_unlock(&session->s_mutex);
1881
1882         /* kick calling process */
1883         complete_request(mdsc, req);
1884 out:
1885         ceph_mdsc_put_request(req);
1886         return;
1887 }
1888
1889
1890
1891 /*
1892  * handle mds notification that our request has been forwarded.
1893  */
1894 static void handle_forward(struct ceph_mds_client *mdsc,
1895                            struct ceph_mds_session *session,
1896                            struct ceph_msg *msg)
1897 {
1898         struct ceph_mds_request *req;
1899         u64 tid;
1900         u32 next_mds;
1901         u32 fwd_seq;
1902         u8 must_resend;
1903         int err = -EINVAL;
1904         void *p = msg->front.iov_base;
1905         void *end = p + msg->front.iov_len;
1906         int state;
1907
1908         ceph_decode_need(&p, end, sizeof(u64)+2*sizeof(u32), bad);
1909         tid = ceph_decode_64(&p);
1910         next_mds = ceph_decode_32(&p);
1911         fwd_seq = ceph_decode_32(&p);
1912         must_resend = ceph_decode_8(&p);
1913
1914         WARN_ON(must_resend);  /* shouldn't happen. */
1915
1916         mutex_lock(&mdsc->mutex);
1917         req = __lookup_request(mdsc, tid);
1918         if (!req) {
1919                 dout("forward %llu dne\n", tid);
1920                 goto out;  /* dup reply? */
1921         }
1922
1923         if (next_mds >= mdsc->max_sessions)
1924                 goto out;
1925
1926         state = mdsc->sessions[next_mds]->s_state;
1927         if (fwd_seq <= req->r_num_fwd) {
1928                 dout("forward %llu to mds%d - old seq %d <= %d\n",
1929                      tid, next_mds, req->r_num_fwd, fwd_seq);
1930         } else {
1931                 /* resend. forward race not possible; mds would drop */
1932                 dout("forward %llu to mds%d (we resend)\n", tid, next_mds);
1933                 req->r_num_fwd = fwd_seq;
1934                 req->r_resend_mds = next_mds;
1935                 put_request_session(req);
1936                 __do_request(mdsc, req);
1937         }
1938         ceph_mdsc_put_request(req);
1939 out:
1940         mutex_unlock(&mdsc->mutex);
1941         return;
1942
1943 bad:
1944         pr_err("mdsc_handle_forward decode error err=%d\n", err);
1945 }
1946
1947 /*
1948  * handle a mds session control message
1949  */
1950 static void handle_session(struct ceph_mds_session *session,
1951                            struct ceph_msg *msg)
1952 {
1953         struct ceph_mds_client *mdsc = session->s_mdsc;
1954         u32 op;
1955         u64 seq;
1956         int mds = session->s_mds;
1957         struct ceph_mds_session_head *h = msg->front.iov_base;
1958         int wake = 0;
1959
1960         /* decode */
1961         if (msg->front.iov_len != sizeof(*h))
1962                 goto bad;
1963         op = le32_to_cpu(h->op);
1964         seq = le64_to_cpu(h->seq);
1965
1966         mutex_lock(&mdsc->mutex);
1967         if (op == CEPH_SESSION_CLOSE)
1968                 __unregister_session(mdsc, session);
1969         /* FIXME: this ttl calculation is generous */
1970         session->s_ttl = jiffies + HZ*mdsc->mdsmap->m_session_autoclose;
1971         mutex_unlock(&mdsc->mutex);
1972
1973         mutex_lock(&session->s_mutex);
1974
1975         dout("handle_session mds%d %s %p state %s seq %llu\n",
1976              mds, ceph_session_op_name(op), session,
1977              session_state_name(session->s_state), seq);
1978
1979         if (session->s_state == CEPH_MDS_SESSION_HUNG) {
1980                 session->s_state = CEPH_MDS_SESSION_OPEN;
1981                 pr_info("mds%d came back\n", session->s_mds);
1982         }
1983
1984         switch (op) {
1985         case CEPH_SESSION_OPEN:
1986                 session->s_state = CEPH_MDS_SESSION_OPEN;
1987                 renewed_caps(mdsc, session, 0);
1988                 wake = 1;
1989                 if (mdsc->stopping)
1990                         __close_session(mdsc, session);
1991                 break;
1992
1993         case CEPH_SESSION_RENEWCAPS:
1994                 if (session->s_renew_seq == seq)
1995                         renewed_caps(mdsc, session, 1);
1996                 break;
1997
1998         case CEPH_SESSION_CLOSE:
1999                 remove_session_caps(session);
2000                 wake = 1; /* for good measure */
2001                 complete(&mdsc->session_close_waiters);
2002                 kick_requests(mdsc, mds, 0);      /* cur only */
2003                 break;
2004
2005         case CEPH_SESSION_STALE:
2006                 pr_info("mds%d caps went stale, renewing\n",
2007                         session->s_mds);
2008                 spin_lock(&session->s_cap_lock);
2009                 session->s_cap_gen++;
2010                 session->s_cap_ttl = 0;
2011                 spin_unlock(&session->s_cap_lock);
2012                 send_renew_caps(mdsc, session);
2013                 break;
2014
2015         case CEPH_SESSION_RECALL_STATE:
2016                 trim_caps(mdsc, session, le32_to_cpu(h->max_caps));
2017                 break;
2018
2019         default:
2020                 pr_err("mdsc_handle_session bad op %d mds%d\n", op, mds);
2021                 WARN_ON(1);
2022         }
2023
2024         mutex_unlock(&session->s_mutex);
2025         if (wake) {
2026                 mutex_lock(&mdsc->mutex);
2027                 __wake_requests(mdsc, &session->s_waiting);
2028                 mutex_unlock(&mdsc->mutex);
2029         }
2030         return;
2031
2032 bad:
2033         pr_err("mdsc_handle_session corrupt message mds%d len %d\n", mds,
2034                (int)msg->front.iov_len);
2035         ceph_msg_dump(msg);
2036         return;
2037 }
2038
2039
2040 /*
2041  * called under session->mutex.
2042  */
2043 static void replay_unsafe_requests(struct ceph_mds_client *mdsc,
2044                                    struct ceph_mds_session *session)
2045 {
2046         struct ceph_mds_request *req, *nreq;
2047         int err;
2048
2049         dout("replay_unsafe_requests mds%d\n", session->s_mds);
2050
2051         mutex_lock(&mdsc->mutex);
2052         list_for_each_entry_safe(req, nreq, &session->s_unsafe, r_unsafe_item) {
2053                 err = __prepare_send_request(mdsc, req, session->s_mds);
2054                 if (!err) {
2055                         ceph_msg_get(req->r_request);
2056                         ceph_con_send(&session->s_con, req->r_request);
2057                 }
2058         }
2059         mutex_unlock(&mdsc->mutex);
2060 }
2061
2062 /*
2063  * Encode information about a cap for a reconnect with the MDS.
2064  */
2065 static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap,
2066                           void *arg)
2067 {
2068         struct ceph_mds_cap_reconnect rec;
2069         struct ceph_inode_info *ci;
2070         struct ceph_pagelist *pagelist = arg;
2071         char *path;
2072         int pathlen, err;
2073         u64 pathbase;
2074         struct dentry *dentry;
2075
2076         ci = cap->ci;
2077
2078         dout(" adding %p ino %llx.%llx cap %p %lld %s\n",
2079              inode, ceph_vinop(inode), cap, cap->cap_id,
2080              ceph_cap_string(cap->issued));
2081         err = ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
2082         if (err)
2083                 return err;
2084
2085         dentry = d_find_alias(inode);
2086         if (dentry) {
2087                 path = ceph_mdsc_build_path(dentry, &pathlen, &pathbase, 0);
2088                 if (IS_ERR(path)) {
2089                         err = PTR_ERR(path);
2090                         BUG_ON(err);
2091                 }
2092         } else {
2093                 path = NULL;
2094                 pathlen = 0;
2095         }
2096         err = ceph_pagelist_encode_string(pagelist, path, pathlen);
2097         if (err)
2098                 goto out;
2099
2100         spin_lock(&inode->i_lock);
2101         cap->seq = 0;        /* reset cap seq */
2102         cap->issue_seq = 0;  /* and issue_seq */
2103         rec.cap_id = cpu_to_le64(cap->cap_id);
2104         rec.pathbase = cpu_to_le64(pathbase);
2105         rec.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
2106         rec.issued = cpu_to_le32(cap->issued);
2107         rec.size = cpu_to_le64(inode->i_size);
2108         ceph_encode_timespec(&rec.mtime, &inode->i_mtime);
2109         ceph_encode_timespec(&rec.atime, &inode->i_atime);
2110         rec.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
2111         spin_unlock(&inode->i_lock);
2112
2113         err = ceph_pagelist_append(pagelist, &rec, sizeof(rec));
2114
2115 out:
2116         kfree(path);
2117         dput(dentry);
2118         return err;
2119 }
2120
2121
2122 /*
2123  * If an MDS fails and recovers, clients need to reconnect in order to
2124  * reestablish shared state.  This includes all caps issued through
2125  * this session _and_ the snap_realm hierarchy.  Because it's not
2126  * clear which snap realms the mds cares about, we send everything we
2127  * know about.. that ensures we'll then get any new info the
2128  * recovering MDS might have.
2129  *
2130  * This is a relatively heavyweight operation, but it's rare.
2131  *
2132  * called with mdsc->mutex held.
2133  */
2134 static void send_mds_reconnect(struct ceph_mds_client *mdsc, int mds)
2135 {
2136         struct ceph_mds_session *session = NULL;
2137         struct ceph_msg *reply;
2138         struct rb_node *p;
2139         int err;
2140         struct ceph_pagelist *pagelist;
2141
2142         pr_info("reconnect to recovering mds%d\n", mds);
2143
2144         pagelist = kmalloc(sizeof(*pagelist), GFP_NOFS);
2145         if (!pagelist)
2146                 goto fail_nopagelist;
2147         ceph_pagelist_init(pagelist);
2148
2149         reply = ceph_msg_new(CEPH_MSG_CLIENT_RECONNECT, 0, 0, 0, NULL);
2150         if (IS_ERR(reply)) {
2151                 err = PTR_ERR(reply);
2152                 goto fail_nomsg;
2153         }
2154
2155         /* find session */
2156         session = __ceph_lookup_mds_session(mdsc, mds);
2157         mutex_unlock(&mdsc->mutex);    /* drop lock for duration */
2158
2159         if (session) {
2160                 mutex_lock(&session->s_mutex);
2161
2162                 session->s_state = CEPH_MDS_SESSION_RECONNECTING;
2163                 session->s_seq = 0;
2164
2165                 ceph_con_open(&session->s_con,
2166                               ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
2167
2168                 /* replay unsafe requests */
2169                 replay_unsafe_requests(mdsc, session);
2170         } else {
2171                 dout("no session for mds%d, will send short reconnect\n",
2172                      mds);
2173         }
2174
2175         down_read(&mdsc->snap_rwsem);
2176
2177         if (!session)
2178                 goto send;
2179         dout("session %p state %s\n", session,
2180              session_state_name(session->s_state));
2181
2182         /* traverse this session's caps */
2183         err = ceph_pagelist_encode_32(pagelist, session->s_nr_caps);
2184         if (err)
2185                 goto fail;
2186         err = iterate_session_caps(session, encode_caps_cb, pagelist);
2187         if (err < 0)
2188                 goto out;
2189
2190         /*
2191          * snaprealms.  we provide mds with the ino, seq (version), and
2192          * parent for all of our realms.  If the mds has any newer info,
2193          * it will tell us.
2194          */
2195         for (p = rb_first(&mdsc->snap_realms); p; p = rb_next(p)) {
2196                 struct ceph_snap_realm *realm =
2197                         rb_entry(p, struct ceph_snap_realm, node);
2198                 struct ceph_mds_snaprealm_reconnect sr_rec;
2199
2200                 dout(" adding snap realm %llx seq %lld parent %llx\n",
2201                      realm->ino, realm->seq, realm->parent_ino);
2202                 sr_rec.ino = cpu_to_le64(realm->ino);
2203                 sr_rec.seq = cpu_to_le64(realm->seq);
2204                 sr_rec.parent = cpu_to_le64(realm->parent_ino);
2205                 err = ceph_pagelist_append(pagelist, &sr_rec, sizeof(sr_rec));
2206                 if (err)
2207                         goto fail;
2208         }
2209
2210 send:
2211         reply->pagelist = pagelist;
2212         reply->hdr.data_len = cpu_to_le32(pagelist->length);
2213         reply->nr_pages = calc_pages_for(0, pagelist->length);
2214         ceph_con_send(&session->s_con, reply);
2215
2216         if (session) {
2217                 session->s_state = CEPH_MDS_SESSION_OPEN;
2218                 __wake_requests(mdsc, &session->s_waiting);
2219         }
2220
2221 out:
2222         up_read(&mdsc->snap_rwsem);
2223         if (session) {
2224                 mutex_unlock(&session->s_mutex);
2225                 ceph_put_mds_session(session);
2226         }
2227         mutex_lock(&mdsc->mutex);
2228         return;
2229
2230 fail:
2231         ceph_msg_put(reply);
2232 fail_nomsg:
2233         ceph_pagelist_release(pagelist);
2234         kfree(pagelist);
2235 fail_nopagelist:
2236         pr_err("ENOMEM preparing reconnect for mds%d\n", mds);
2237         goto out;
2238 }
2239
2240
2241 /*
2242  * compare old and new mdsmaps, kicking requests
2243  * and closing out old connections as necessary
2244  *
2245  * called under mdsc->mutex.
2246  */
2247 static void check_new_map(struct ceph_mds_client *mdsc,
2248                           struct ceph_mdsmap *newmap,
2249                           struct ceph_mdsmap *oldmap)
2250 {
2251         int i;
2252         int oldstate, newstate;
2253         struct ceph_mds_session *s;
2254
2255         dout("check_new_map new %u old %u\n",
2256              newmap->m_epoch, oldmap->m_epoch);
2257
2258         for (i = 0; i < oldmap->m_max_mds && i < mdsc->max_sessions; i++) {
2259                 if (mdsc->sessions[i] == NULL)
2260                         continue;
2261                 s = mdsc->sessions[i];
2262                 oldstate = ceph_mdsmap_get_state(oldmap, i);
2263                 newstate = ceph_mdsmap_get_state(newmap, i);
2264
2265                 dout("check_new_map mds%d state %s -> %s (session %s)\n",
2266                      i, ceph_mds_state_name(oldstate),
2267                      ceph_mds_state_name(newstate),
2268                      session_state_name(s->s_state));
2269
2270                 if (memcmp(ceph_mdsmap_get_addr(oldmap, i),
2271                            ceph_mdsmap_get_addr(newmap, i),
2272                            sizeof(struct ceph_entity_addr))) {
2273                         if (s->s_state == CEPH_MDS_SESSION_OPENING) {
2274                                 /* the session never opened, just close it
2275                                  * out now */
2276                                 __wake_requests(mdsc, &s->s_waiting);
2277                                 __unregister_session(mdsc, s);
2278                         } else {
2279                                 /* just close it */
2280                                 mutex_unlock(&mdsc->mutex);
2281                                 mutex_lock(&s->s_mutex);
2282                                 mutex_lock(&mdsc->mutex);
2283                                 ceph_con_close(&s->s_con);
2284                                 mutex_unlock(&s->s_mutex);
2285                                 s->s_state = CEPH_MDS_SESSION_RESTARTING;
2286                         }
2287
2288                         /* kick any requests waiting on the recovering mds */
2289                         kick_requests(mdsc, i, 1);
2290                 } else if (oldstate == newstate) {
2291                         continue;  /* nothing new with this mds */
2292                 }
2293
2294                 /*
2295                  * send reconnect?
2296                  */
2297                 if (s->s_state == CEPH_MDS_SESSION_RESTARTING &&
2298                     newstate >= CEPH_MDS_STATE_RECONNECT)
2299                         send_mds_reconnect(mdsc, i);
2300
2301                 /*
2302                  * kick requests on any mds that has gone active.
2303                  *
2304                  * kick requests on cur or forwarder: we may have sent
2305                  * the request to mds1, mds1 told us it forwarded it
2306                  * to mds2, but then we learn mds1 failed and can't be
2307                  * sure it successfully forwarded our request before
2308                  * it died.
2309                  */
2310                 if (oldstate < CEPH_MDS_STATE_ACTIVE &&
2311                     newstate >= CEPH_MDS_STATE_ACTIVE) {
2312                         pr_info("mds%d reconnect completed\n", s->s_mds);
2313                         kick_requests(mdsc, i, 1);
2314                         ceph_kick_flushing_caps(mdsc, s);
2315                         wake_up_session_caps(s, 1);
2316                 }
2317         }
2318 }
2319
2320
2321
2322 /*
2323  * leases
2324  */
2325
2326 /*
2327  * caller must hold session s_mutex, dentry->d_lock
2328  */
2329 void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry)
2330 {
2331         struct ceph_dentry_info *di = ceph_dentry(dentry);
2332
2333         ceph_put_mds_session(di->lease_session);
2334         di->lease_session = NULL;
2335 }
2336
2337 static void handle_lease(struct ceph_mds_client *mdsc,
2338                          struct ceph_mds_session *session,
2339                          struct ceph_msg *msg)
2340 {
2341         struct super_block *sb = mdsc->client->sb;
2342         struct inode *inode;
2343         struct ceph_inode_info *ci;
2344         struct dentry *parent, *dentry;
2345         struct ceph_dentry_info *di;
2346         int mds = session->s_mds;
2347         struct ceph_mds_lease *h = msg->front.iov_base;
2348         struct ceph_vino vino;
2349         int mask;
2350         struct qstr dname;
2351         int release = 0;
2352
2353         dout("handle_lease from mds%d\n", mds);
2354
2355         /* decode */
2356         if (msg->front.iov_len < sizeof(*h) + sizeof(u32))
2357                 goto bad;
2358         vino.ino = le64_to_cpu(h->ino);
2359         vino.snap = CEPH_NOSNAP;
2360         mask = le16_to_cpu(h->mask);
2361         dname.name = (void *)h + sizeof(*h) + sizeof(u32);
2362         dname.len = msg->front.iov_len - sizeof(*h) - sizeof(u32);
2363         if (dname.len != get_unaligned_le32(h+1))
2364                 goto bad;
2365
2366         mutex_lock(&session->s_mutex);
2367         session->s_seq++;
2368
2369         /* lookup inode */
2370         inode = ceph_find_inode(sb, vino);
2371         dout("handle_lease '%s', mask %d, ino %llx %p\n",
2372              ceph_lease_op_name(h->action), mask, vino.ino, inode);
2373         if (inode == NULL) {
2374                 dout("handle_lease no inode %llx\n", vino.ino);
2375                 goto release;
2376         }
2377         ci = ceph_inode(inode);
2378
2379         /* dentry */
2380         parent = d_find_alias(inode);
2381         if (!parent) {
2382                 dout("no parent dentry on inode %p\n", inode);
2383                 WARN_ON(1);
2384                 goto release;  /* hrm... */
2385         }
2386         dname.hash = full_name_hash(dname.name, dname.len);
2387         dentry = d_lookup(parent, &dname);
2388         dput(parent);
2389         if (!dentry)
2390                 goto release;
2391
2392         spin_lock(&dentry->d_lock);
2393         di = ceph_dentry(dentry);
2394         switch (h->action) {
2395         case CEPH_MDS_LEASE_REVOKE:
2396                 if (di && di->lease_session == session) {
2397                         h->seq = cpu_to_le32(di->lease_seq);
2398                         __ceph_mdsc_drop_dentry_lease(dentry);
2399                 }
2400                 release = 1;
2401                 break;
2402
2403         case CEPH_MDS_LEASE_RENEW:
2404                 if (di && di->lease_session == session &&
2405                     di->lease_gen == session->s_cap_gen &&
2406                     di->lease_renew_from &&
2407                     di->lease_renew_after == 0) {
2408                         unsigned long duration =
2409                                 le32_to_cpu(h->duration_ms) * HZ / 1000;
2410
2411                         di->lease_seq = le32_to_cpu(h->seq);
2412                         dentry->d_time = di->lease_renew_from + duration;
2413                         di->lease_renew_after = di->lease_renew_from +
2414                                 (duration >> 1);
2415                         di->lease_renew_from = 0;
2416                 }
2417                 break;
2418         }
2419         spin_unlock(&dentry->d_lock);
2420         dput(dentry);
2421
2422         if (!release)
2423                 goto out;
2424
2425 release:
2426         /* let's just reuse the same message */
2427         h->action = CEPH_MDS_LEASE_REVOKE_ACK;
2428         ceph_msg_get(msg);
2429         ceph_con_send(&session->s_con, msg);
2430
2431 out:
2432         iput(inode);
2433         mutex_unlock(&session->s_mutex);
2434         return;
2435
2436 bad:
2437         pr_err("corrupt lease message\n");
2438         ceph_msg_dump(msg);
2439 }
2440
2441 void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
2442                               struct inode *inode,
2443                               struct dentry *dentry, char action,
2444                               u32 seq)
2445 {
2446         struct ceph_msg *msg;
2447         struct ceph_mds_lease *lease;
2448         int len = sizeof(*lease) + sizeof(u32);
2449         int dnamelen = 0;
2450
2451         dout("lease_send_msg inode %p dentry %p %s to mds%d\n",
2452              inode, dentry, ceph_lease_op_name(action), session->s_mds);
2453         dnamelen = dentry->d_name.len;
2454         len += dnamelen;
2455
2456         msg = ceph_msg_new(CEPH_MSG_CLIENT_LEASE, len, 0, 0, NULL);
2457         if (IS_ERR(msg))
2458                 return;
2459         lease = msg->front.iov_base;
2460         lease->action = action;
2461         lease->mask = cpu_to_le16(CEPH_LOCK_DN);
2462         lease->ino = cpu_to_le64(ceph_vino(inode).ino);
2463         lease->first = lease->last = cpu_to_le64(ceph_vino(inode).snap);
2464         lease->seq = cpu_to_le32(seq);
2465         put_unaligned_le32(dnamelen, lease + 1);
2466         memcpy((void *)(lease + 1) + 4, dentry->d_name.name, dnamelen);
2467
2468         /*
2469          * if this is a preemptive lease RELEASE, no need to
2470          * flush request stream, since the actual request will
2471          * soon follow.
2472          */
2473         msg->more_to_follow = (action == CEPH_MDS_LEASE_RELEASE);
2474
2475         ceph_con_send(&session->s_con, msg);
2476 }
2477
2478 /*
2479  * Preemptively release a lease we expect to invalidate anyway.
2480  * Pass @inode always, @dentry is optional.
2481  */
2482 void ceph_mdsc_lease_release(struct ceph_mds_client *mdsc, struct inode *inode,
2483                              struct dentry *dentry, int mask)
2484 {
2485         struct ceph_dentry_info *di;
2486         struct ceph_mds_session *session;
2487         u32 seq;
2488
2489         BUG_ON(inode == NULL);
2490         BUG_ON(dentry == NULL);
2491         BUG_ON(mask != CEPH_LOCK_DN);
2492
2493         /* is dentry lease valid? */
2494         spin_lock(&dentry->d_lock);
2495         di = ceph_dentry(dentry);
2496         if (!di || !di->lease_session ||
2497             di->lease_session->s_mds < 0 ||
2498             di->lease_gen != di->lease_session->s_cap_gen ||
2499             !time_before(jiffies, dentry->d_time)) {
2500                 dout("lease_release inode %p dentry %p -- "
2501                      "no lease on %d\n",
2502                      inode, dentry, mask);
2503                 spin_unlock(&dentry->d_lock);
2504                 return;
2505         }
2506
2507         /* we do have a lease on this dentry; note mds and seq */
2508         session = ceph_get_mds_session(di->lease_session);
2509         seq = di->lease_seq;
2510         __ceph_mdsc_drop_dentry_lease(dentry);
2511         spin_unlock(&dentry->d_lock);
2512
2513         dout("lease_release inode %p dentry %p mask %d to mds%d\n",
2514              inode, dentry, mask, session->s_mds);
2515         ceph_mdsc_lease_send_msg(session, inode, dentry,
2516                                  CEPH_MDS_LEASE_RELEASE, seq);
2517         ceph_put_mds_session(session);
2518 }
2519
2520 /*
2521  * drop all leases (and dentry refs) in preparation for umount
2522  */
2523 static void drop_leases(struct ceph_mds_client *mdsc)
2524 {
2525         int i;
2526
2527         dout("drop_leases\n");
2528         mutex_lock(&mdsc->mutex);
2529         for (i = 0; i < mdsc->max_sessions; i++) {
2530                 struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
2531                 if (!s)
2532                         continue;
2533                 mutex_unlock(&mdsc->mutex);
2534                 mutex_lock(&s->s_mutex);
2535                 mutex_unlock(&s->s_mutex);
2536                 ceph_put_mds_session(s);
2537                 mutex_lock(&mdsc->mutex);
2538         }
2539         mutex_unlock(&mdsc->mutex);
2540 }
2541
2542
2543
2544 /*
2545  * delayed work -- periodically trim expired leases, renew caps with mds
2546  */
2547 static void schedule_delayed(struct ceph_mds_client *mdsc)
2548 {
2549         int delay = 5;
2550         unsigned hz = round_jiffies_relative(HZ * delay);
2551         schedule_delayed_work(&mdsc->delayed_work, hz);
2552 }
2553
2554 static void delayed_work(struct work_struct *work)
2555 {
2556         int i;
2557         struct ceph_mds_client *mdsc =
2558                 container_of(work, struct ceph_mds_client, delayed_work.work);
2559         int renew_interval;
2560         int renew_caps;
2561
2562         dout("mdsc delayed_work\n");
2563         ceph_check_delayed_caps(mdsc);
2564
2565         mutex_lock(&mdsc->mutex);
2566         renew_interval = mdsc->mdsmap->m_session_timeout >> 2;
2567         renew_caps = time_after_eq(jiffies, HZ*renew_interval +
2568                                    mdsc->last_renew_caps);
2569         if (renew_caps)
2570                 mdsc->last_renew_caps = jiffies;
2571
2572         for (i = 0; i < mdsc->max_sessions; i++) {
2573                 struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
2574                 if (s == NULL)
2575                         continue;
2576                 if (s->s_state == CEPH_MDS_SESSION_CLOSING) {
2577                         dout("resending session close request for mds%d\n",
2578                              s->s_mds);
2579                         request_close_session(mdsc, s);
2580                         ceph_put_mds_session(s);
2581                         continue;
2582                 }
2583                 if (s->s_ttl && time_after(jiffies, s->s_ttl)) {
2584                         if (s->s_state == CEPH_MDS_SESSION_OPEN) {
2585                                 s->s_state = CEPH_MDS_SESSION_HUNG;
2586                                 pr_info("mds%d hung\n", s->s_mds);
2587                         }
2588                 }
2589                 if (s->s_state < CEPH_MDS_SESSION_OPEN) {
2590                         /* this mds is failed or recovering, just wait */
2591                         ceph_put_mds_session(s);
2592                         continue;
2593                 }
2594                 mutex_unlock(&mdsc->mutex);
2595
2596                 mutex_lock(&s->s_mutex);
2597                 if (renew_caps)
2598                         send_renew_caps(mdsc, s);
2599                 else
2600                         ceph_con_keepalive(&s->s_con);
2601                 add_cap_releases(mdsc, s, -1);
2602                 send_cap_releases(mdsc, s);
2603                 mutex_unlock(&s->s_mutex);
2604                 ceph_put_mds_session(s);
2605
2606                 mutex_lock(&mdsc->mutex);
2607         }
2608         mutex_unlock(&mdsc->mutex);
2609
2610         schedule_delayed(mdsc);
2611 }
2612
2613
2614 int ceph_mdsc_init(struct ceph_mds_client *mdsc, struct ceph_client *client)
2615 {
2616         mdsc->client = client;
2617         mutex_init(&mdsc->mutex);
2618         mdsc->mdsmap = kzalloc(sizeof(*mdsc->mdsmap), GFP_NOFS);
2619         init_completion(&mdsc->safe_umount_waiters);
2620         init_completion(&mdsc->session_close_waiters);
2621         INIT_LIST_HEAD(&mdsc->waiting_for_map);
2622         mdsc->sessions = NULL;
2623         mdsc->max_sessions = 0;
2624         mdsc->stopping = 0;
2625         init_rwsem(&mdsc->snap_rwsem);
2626         mdsc->snap_realms = RB_ROOT;
2627         INIT_LIST_HEAD(&mdsc->snap_empty);
2628         spin_lock_init(&mdsc->snap_empty_lock);
2629         mdsc->last_tid = 0;
2630         mdsc->request_tree = RB_ROOT;
2631         INIT_DELAYED_WORK(&mdsc->delayed_work, delayed_work);
2632         mdsc->last_renew_caps = jiffies;
2633         INIT_LIST_HEAD(&mdsc->cap_delay_list);
2634         spin_lock_init(&mdsc->cap_delay_lock);
2635         INIT_LIST_HEAD(&mdsc->snap_flush_list);
2636         spin_lock_init(&mdsc->snap_flush_lock);
2637         mdsc->cap_flush_seq = 0;
2638         INIT_LIST_HEAD(&mdsc->cap_dirty);
2639         mdsc->num_cap_flushing = 0;
2640         spin_lock_init(&mdsc->cap_dirty_lock);
2641         init_waitqueue_head(&mdsc->cap_flushing_wq);
2642         spin_lock_init(&mdsc->dentry_lru_lock);
2643         INIT_LIST_HEAD(&mdsc->dentry_lru);
2644         return 0;
2645 }
2646
2647 /*
2648  * Wait for safe replies on open mds requests.  If we time out, drop
2649  * all requests from the tree to avoid dangling dentry refs.
2650  */
2651 static void wait_requests(struct ceph_mds_client *mdsc)
2652 {
2653         struct ceph_mds_request *req;
2654         struct ceph_client *client = mdsc->client;
2655
2656         mutex_lock(&mdsc->mutex);
2657         if (__get_oldest_req(mdsc)) {
2658                 mutex_unlock(&mdsc->mutex);
2659
2660                 dout("wait_requests waiting for requests\n");
2661                 wait_for_completion_timeout(&mdsc->safe_umount_waiters,
2662                                     client->mount_args->mount_timeout * HZ);
2663
2664                 /* tear down remaining requests */
2665                 mutex_lock(&mdsc->mutex);
2666                 while ((req = __get_oldest_req(mdsc))) {
2667                         dout("wait_requests timed out on tid %llu\n",
2668                              req->r_tid);
2669                         __unregister_request(mdsc, req);
2670                 }
2671         }
2672         mutex_unlock(&mdsc->mutex);
2673         dout("wait_requests done\n");
2674 }
2675
2676 /*
2677  * called before mount is ro, and before dentries are torn down.
2678  * (hmm, does this still race with new lookups?)
2679  */
2680 void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc)
2681 {
2682         dout("pre_umount\n");
2683         mdsc->stopping = 1;
2684
2685         drop_leases(mdsc);
2686         ceph_flush_dirty_caps(mdsc);
2687         wait_requests(mdsc);
2688 }
2689
2690 /*
2691  * wait for all write mds requests to flush.
2692  */
2693 static void wait_unsafe_requests(struct ceph_mds_client *mdsc, u64 want_tid)
2694 {
2695         struct ceph_mds_request *req = NULL;
2696         struct rb_node *n;
2697
2698         mutex_lock(&mdsc->mutex);
2699         dout("wait_unsafe_requests want %lld\n", want_tid);
2700         req = __get_oldest_req(mdsc);
2701         while (req && req->r_tid <= want_tid) {
2702                 if ((req->r_op & CEPH_MDS_OP_WRITE)) {
2703                         /* write op */
2704                         ceph_mdsc_get_request(req);
2705                         mutex_unlock(&mdsc->mutex);
2706                         dout("wait_unsafe_requests  wait on %llu (want %llu)\n",
2707                              req->r_tid, want_tid);
2708                         wait_for_completion(&req->r_safe_completion);
2709                         mutex_lock(&mdsc->mutex);
2710                         n = rb_next(&req->r_node);
2711                         ceph_mdsc_put_request(req);
2712                 } else {
2713                         n = rb_next(&req->r_node);
2714                 }
2715                 if (!n)
2716                         break;
2717                 req = rb_entry(n, struct ceph_mds_request, r_node);
2718         }
2719         mutex_unlock(&mdsc->mutex);
2720         dout("wait_unsafe_requests done\n");
2721 }
2722
2723 void ceph_mdsc_sync(struct ceph_mds_client *mdsc)
2724 {
2725         u64 want_tid, want_flush;
2726
2727         dout("sync\n");
2728         mutex_lock(&mdsc->mutex);
2729         want_tid = mdsc->last_tid;
2730         want_flush = mdsc->cap_flush_seq;
2731         mutex_unlock(&mdsc->mutex);
2732         dout("sync want tid %lld flush_seq %lld\n", want_tid, want_flush);
2733
2734         ceph_flush_dirty_caps(mdsc);
2735
2736         wait_unsafe_requests(mdsc, want_tid);
2737         wait_event(mdsc->cap_flushing_wq, check_cap_flush(mdsc, want_flush));
2738 }
2739
2740
2741 /*
2742  * called after sb is ro.
2743  */
2744 void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc)
2745 {
2746         struct ceph_mds_session *session;
2747         int i;
2748         int n;
2749         struct ceph_client *client = mdsc->client;
2750         unsigned long started, timeout = client->mount_args->mount_timeout * HZ;
2751
2752         dout("close_sessions\n");
2753
2754         mutex_lock(&mdsc->mutex);
2755
2756         /* close sessions */
2757         started = jiffies;
2758         while (time_before(jiffies, started + timeout)) {
2759                 dout("closing sessions\n");
2760                 n = 0;
2761                 for (i = 0; i < mdsc->max_sessions; i++) {
2762                         session = __ceph_lookup_mds_session(mdsc, i);
2763                         if (!session)
2764                                 continue;
2765                         mutex_unlock(&mdsc->mutex);
2766                         mutex_lock(&session->s_mutex);
2767                         __close_session(mdsc, session);
2768                         mutex_unlock(&session->s_mutex);
2769                         ceph_put_mds_session(session);
2770                         mutex_lock(&mdsc->mutex);
2771                         n++;
2772                 }
2773                 if (n == 0)
2774                         break;
2775
2776                 if (client->mount_state == CEPH_MOUNT_SHUTDOWN)
2777                         break;
2778
2779                 dout("waiting for sessions to close\n");
2780                 mutex_unlock(&mdsc->mutex);
2781                 wait_for_completion_timeout(&mdsc->session_close_waiters,
2782                                             timeout);
2783                 mutex_lock(&mdsc->mutex);
2784         }
2785
2786         /* tear down remaining sessions */
2787         for (i = 0; i < mdsc->max_sessions; i++) {
2788                 if (mdsc->sessions[i]) {
2789                         session = get_session(mdsc->sessions[i]);
2790                         __unregister_session(mdsc, session);
2791                         mutex_unlock(&mdsc->mutex);
2792                         mutex_lock(&session->s_mutex);
2793                         remove_session_caps(session);
2794                         mutex_unlock(&session->s_mutex);
2795                         ceph_put_mds_session(session);
2796                         mutex_lock(&mdsc->mutex);
2797                 }
2798         }
2799
2800         WARN_ON(!list_empty(&mdsc->cap_delay_list));
2801
2802         mutex_unlock(&mdsc->mutex);
2803
2804         ceph_cleanup_empty_realms(mdsc);
2805
2806         cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
2807
2808         dout("stopped\n");
2809 }
2810
2811 void ceph_mdsc_stop(struct ceph_mds_client *mdsc)
2812 {
2813         dout("stop\n");
2814         cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
2815         if (mdsc->mdsmap)
2816                 ceph_mdsmap_destroy(mdsc->mdsmap);
2817         kfree(mdsc->sessions);
2818 }
2819
2820
2821 /*
2822  * handle mds map update.
2823  */
2824 void ceph_mdsc_handle_map(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
2825 {
2826         u32 epoch;
2827         u32 maplen;
2828         void *p = msg->front.iov_base;
2829         void *end = p + msg->front.iov_len;
2830         struct ceph_mdsmap *newmap, *oldmap;
2831         struct ceph_fsid fsid;
2832         int err = -EINVAL;
2833
2834         ceph_decode_need(&p, end, sizeof(fsid)+2*sizeof(u32), bad);
2835         ceph_decode_copy(&p, &fsid, sizeof(fsid));
2836         if (ceph_check_fsid(mdsc->client, &fsid) < 0)
2837                 return;
2838         epoch = ceph_decode_32(&p);
2839         maplen = ceph_decode_32(&p);
2840         dout("handle_map epoch %u len %d\n", epoch, (int)maplen);
2841
2842         /* do we need it? */
2843         ceph_monc_got_mdsmap(&mdsc->client->monc, epoch);
2844         mutex_lock(&mdsc->mutex);
2845         if (mdsc->mdsmap && epoch <= mdsc->mdsmap->m_epoch) {
2846                 dout("handle_map epoch %u <= our %u\n",
2847                      epoch, mdsc->mdsmap->m_epoch);
2848                 mutex_unlock(&mdsc->mutex);
2849                 return;
2850         }
2851
2852         newmap = ceph_mdsmap_decode(&p, end);
2853         if (IS_ERR(newmap)) {
2854                 err = PTR_ERR(newmap);
2855                 goto bad_unlock;
2856         }
2857
2858         /* swap into place */
2859         if (mdsc->mdsmap) {
2860                 oldmap = mdsc->mdsmap;
2861                 mdsc->mdsmap = newmap;
2862                 check_new_map(mdsc, newmap, oldmap);
2863                 ceph_mdsmap_destroy(oldmap);
2864         } else {
2865                 mdsc->mdsmap = newmap;  /* first mds map */
2866         }
2867         mdsc->client->sb->s_maxbytes = mdsc->mdsmap->m_max_file_size;
2868
2869         __wake_requests(mdsc, &mdsc->waiting_for_map);
2870
2871         mutex_unlock(&mdsc->mutex);
2872         schedule_delayed(mdsc);
2873         return;
2874
2875 bad_unlock:
2876         mutex_unlock(&mdsc->mutex);
2877 bad:
2878         pr_err("error decoding mdsmap %d\n", err);
2879         return;
2880 }
2881
2882 static struct ceph_connection *con_get(struct ceph_connection *con)
2883 {
2884         struct ceph_mds_session *s = con->private;
2885
2886         if (get_session(s)) {
2887                 dout("mdsc con_get %p ok (%d)\n", s, atomic_read(&s->s_ref));
2888                 return con;
2889         }
2890         dout("mdsc con_get %p FAIL\n", s);
2891         return NULL;
2892 }
2893
2894 static void con_put(struct ceph_connection *con)
2895 {
2896         struct ceph_mds_session *s = con->private;
2897
2898         ceph_put_mds_session(s);
2899         dout("mdsc con_put %p (%d)\n", s, atomic_read(&s->s_ref));
2900 }
2901
2902 /*
2903  * if the client is unresponsive for long enough, the mds will kill
2904  * the session entirely.
2905  */
2906 static void peer_reset(struct ceph_connection *con)
2907 {
2908         struct ceph_mds_session *s = con->private;
2909
2910         pr_err("mds%d gave us the boot.  IMPLEMENT RECONNECT.\n",
2911                s->s_mds);
2912 }
2913
2914 static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
2915 {
2916         struct ceph_mds_session *s = con->private;
2917         struct ceph_mds_client *mdsc = s->s_mdsc;
2918         int type = le16_to_cpu(msg->hdr.type);
2919
2920         mutex_lock(&mdsc->mutex);
2921         if (__verify_registered_session(mdsc, s) < 0) {
2922                 mutex_unlock(&mdsc->mutex);
2923                 goto out;
2924         }
2925         mutex_unlock(&mdsc->mutex);
2926
2927         switch (type) {
2928         case CEPH_MSG_MDS_MAP:
2929                 ceph_mdsc_handle_map(mdsc, msg);
2930                 break;
2931         case CEPH_MSG_CLIENT_SESSION:
2932                 handle_session(s, msg);
2933                 break;
2934         case CEPH_MSG_CLIENT_REPLY:
2935                 handle_reply(s, msg);
2936                 break;
2937         case CEPH_MSG_CLIENT_REQUEST_FORWARD:
2938                 handle_forward(mdsc, s, msg);
2939                 break;
2940         case CEPH_MSG_CLIENT_CAPS:
2941                 ceph_handle_caps(s, msg);
2942                 break;
2943         case CEPH_MSG_CLIENT_SNAP:
2944                 ceph_handle_snap(mdsc, s, msg);
2945                 break;
2946         case CEPH_MSG_CLIENT_LEASE:
2947                 handle_lease(mdsc, s, msg);
2948                 break;
2949
2950         default:
2951                 pr_err("received unknown message type %d %s\n", type,
2952                        ceph_msg_type_name(type));
2953         }
2954 out:
2955         ceph_msg_put(msg);
2956 }
2957
2958 /*
2959  * authentication
2960  */
2961 static int get_authorizer(struct ceph_connection *con,
2962                           void **buf, int *len, int *proto,
2963                           void **reply_buf, int *reply_len, int force_new)
2964 {
2965         struct ceph_mds_session *s = con->private;
2966         struct ceph_mds_client *mdsc = s->s_mdsc;
2967         struct ceph_auth_client *ac = mdsc->client->monc.auth;
2968         int ret = 0;
2969
2970         if (force_new && s->s_authorizer) {
2971                 ac->ops->destroy_authorizer(ac, s->s_authorizer);
2972                 s->s_authorizer = NULL;
2973         }
2974         if (s->s_authorizer == NULL) {
2975                 if (ac->ops->create_authorizer) {
2976                         ret = ac->ops->create_authorizer(
2977                                 ac, CEPH_ENTITY_TYPE_MDS,
2978                                 &s->s_authorizer,
2979                                 &s->s_authorizer_buf,
2980                                 &s->s_authorizer_buf_len,
2981                                 &s->s_authorizer_reply_buf,
2982                                 &s->s_authorizer_reply_buf_len);
2983                         if (ret)
2984                                 return ret;
2985                 }
2986         }
2987
2988         *proto = ac->protocol;
2989         *buf = s->s_authorizer_buf;
2990         *len = s->s_authorizer_buf_len;
2991         *reply_buf = s->s_authorizer_reply_buf;
2992         *reply_len = s->s_authorizer_reply_buf_len;
2993         return 0;
2994 }
2995
2996
2997 static int verify_authorizer_reply(struct ceph_connection *con, int len)
2998 {
2999         struct ceph_mds_session *s = con->private;
3000         struct ceph_mds_client *mdsc = s->s_mdsc;
3001         struct ceph_auth_client *ac = mdsc->client->monc.auth;
3002
3003         return ac->ops->verify_authorizer_reply(ac, s->s_authorizer, len);
3004 }
3005
3006 static int invalidate_authorizer(struct ceph_connection *con)
3007 {
3008         struct ceph_mds_session *s = con->private;
3009         struct ceph_mds_client *mdsc = s->s_mdsc;
3010         struct ceph_auth_client *ac = mdsc->client->monc.auth;
3011
3012         if (ac->ops->invalidate_authorizer)
3013                 ac->ops->invalidate_authorizer(ac, CEPH_ENTITY_TYPE_MDS);
3014
3015         return ceph_monc_validate_auth(&mdsc->client->monc);
3016 }
3017
3018 const static struct ceph_connection_operations mds_con_ops = {
3019         .get = con_get,
3020         .put = con_put,
3021         .dispatch = dispatch,
3022         .get_authorizer = get_authorizer,
3023         .verify_authorizer_reply = verify_authorizer_reply,
3024         .invalidate_authorizer = invalidate_authorizer,
3025         .peer_reset = peer_reset,
3026 };
3027
3028
3029
3030
3031 /* eof */