fs/ceph/mds_client.c

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  41  * are no longer valid.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