fs/ceph/mds_client.c

   1 #include "ceph_debug.h"
   2
   3 #include <linux/wait.h>
   4 #include <linux/slab.h>
   5 #include <linux/sched.h>
   6
   7 #include "mds_client.h"
   8 #include "mon_client.h"
   9 #include "super.h"
  10 #include "messenger.h"
  11 #include "decode.h"
  12 #include "auth.h"
  13 #include "pagelist.h"
  14
  15 /*
  16  * A cluster of MDS (metadata server) daemons is responsible for
  17  * managing the file system namespace (the directory hierarchy and
  18  * inodes) and for coordinating shared access to storage.  Metadata is
  19  * partitioning hierarchically across a number of servers, and that
  20  * partition varies over time as the cluster adjusts the distribution
  21  * in order to balance load.
  22  *
  23  * The MDS client is primarily responsible to managing synchronous
  24  * metadata requests for operations like open, unlink, and so forth.
  25  * If there is a MDS failure, we find out about it when we (possibly
  26  * request and) receive a new MDS map, and can resubmit affected
  27  * requests.
  28  *
  29  * For the most part, though, we take advantage of a lossless
  30  * communications channel to the MDS, and do not need to worry about
  31  * timing out or resubmitting requests.
  32  *
  33  * We maintain a stateful "session" with each MDS we interact with.
  34  * Within each session, we sent periodic heartbeat messages to ensure
  35  * any capabilities or leases we have been issues remain valid.  If
  36  * the session times out and goes stale, our leases and capabilities
  37  * are no longer valid.
  38  */
  39
  40 static void __wake_requests(struct ceph_mds_client *mdsc,
  41                             struct list_head *head);
  42
  43 const static struct ceph_connection_operations mds_con_ops;
  44
  45
  46 /*
  47  * mds reply parsing
  48  */
  49
  50 /*
  51  * parse individual inode info
  52  */
  53 static int parse_reply_info_in(void **p, void *end,
  54                                struct ceph_mds_reply_info_in *info)
  55 {
  56         int err = -EIO;
  57
  58         info->in = *p;
  59         *p += sizeof(struct ceph_mds_reply_inode) +
  60                 sizeof(*info->in->fragtree.splits) *
  61                 le32_to_cpu(info->in->fragtree.nsplits);
  62
  63         ceph_decode_32_safe(p, end, info->symlink_len, bad);
  64         ceph_decode_need(p, end, info->symlink_len, bad);
  65         info->symlink = *p;
  66         *p += info->symlink_len;
  67
  68         ceph_decode_32_safe(p, end, info->xattr_len, bad);
  69         ceph_decode_need(p, end, info->xattr_len, bad);
  70         info->xattr_data = *p;
  71         *p += info->xattr_len;
  72         return 0;
  73 bad:
  74         return err;
  75 }
  76
  77 /*
  78  * parse a normal reply, which may contain a (dir+)dentry and/or a
  79  * target inode.
  80  */
  81 static int parse_reply_info_trace(void **p, void *end,
  82                                   struct ceph_mds_reply_info_parsed *info)
  83 {
  84         int err;
  85
  86         if (info->head->is_dentry) {
  87                 err = parse_reply_info_in(p, end, &info->diri);
  88                 if (err < 0)
  89                         goto out_bad;
  90
  91                 if (unlikely(*p + sizeof(*info->dirfrag) > end))
  92                         goto bad;
  93                 info->dirfrag = *p;
  94                 *p += sizeof(*info->dirfrag) +
  95                         sizeof(u32)*le32_to_cpu(info->dirfrag->ndist);
  96                 if (unlikely(*p > end))
  97                         goto bad;
  98
  99                 ceph_decode_32_safe(p, end, info->dname_len, bad);
 100                 ceph_decode_need(p, end, info->dname_len, bad);
 101                 info->dname = *p;
 102                 *p += info->dname_len;
 103                 info->dlease = *p;
 104                 *p += sizeof(*info->dlease);
 105         }
 106
 107         if (info->head->is_target) {
 108                 err = parse_reply_info_in(p, end, &info->targeti);
 109                 if (err < 0)
 110                         goto out_bad;
 111         }
 112
 113         if (unlikely(*p != end))
 114                 goto bad;
 115         return 0;
 116
 117 bad:
 118         err = -EIO;
 119 out_bad:
 120         pr_err("problem parsing mds trace %d\n", err);
 121         return err;
 122 }
 123
 124 /*
 125  * parse readdir results
 126  */
 127 static int parse_reply_info_dir(void **p, void *end,
 128                                 struct ceph_mds_reply_info_parsed *info)
 129 {
 130         u32 num, i = 0;
 131         int err;
 132
 133         info->dir_dir = *p;
 134         if (*p + sizeof(*info->dir_dir) > end)
 135                 goto bad;
 136         *p += sizeof(*info->dir_dir) +
 137                 sizeof(u32)*le32_to_cpu(info->dir_dir->ndist);
 138         if (*p > end)
 139                 goto bad;
 140
 141         ceph_decode_need(p, end, sizeof(num) + 2, bad);
 142         num = ceph_decode_32(p);
 143         info->dir_end = ceph_decode_8(p);
 144         info->dir_complete = ceph_decode_8(p);
 145         if (num == 0)
 146                 goto done;
 147
 148         /* alloc large array */
 149         info->dir_nr = num;
 150         info->dir_in = kcalloc(num, sizeof(*info->dir_in) +
 151                                sizeof(*info->dir_dname) +
 152                                sizeof(*info->dir_dname_len) +
 153                                sizeof(*info->dir_dlease),
 154                                GFP_NOFS);
 155         if (info->dir_in == NULL) {
 156                 err = -ENOMEM;
 157                 goto out_bad;
 158         }
 159         info->dir_dname = (void *)(info->dir_in + num);
 160         info->dir_dname_len = (void *)(info->dir_dname + num);
 161         info->dir_dlease = (void *)(info->dir_dname_len + num);
 162
 163         while (num) {
 164                 /* dentry */
 165                 ceph_decode_need(p, end, sizeof(u32)*2, bad);
 166                 info->dir_dname_len[i] = ceph_decode_32(p);
 167                 ceph_decode_need(p, end, info->dir_dname_len[i], bad);
 168                 info->dir_dname[i] = *p;
 169                 *p += info->dir_dname_len[i];
 170                 dout("parsed dir dname '%.*s'\n", info->dir_dname_len[i],
 171                      info->dir_dname[i]);
 172                 info->dir_dlease[i] = *p;
 173                 *p += sizeof(struct ceph_mds_reply_lease);
 174
 175                 /* inode */
 176                 err = parse_reply_info_in(p, end, &info->dir_in[i]);
 177                 if (err < 0)
 178                         goto out_bad;
 179                 i++;
 180                 num--;
 181         }
 182
 183 done:
 184         if (*p != end)
 185                 goto bad;
 186         return 0;
 187
 188 bad:
 189         err = -EIO;
 190 out_bad:
 191         pr_err("problem parsing dir contents %d\n", err);
 192         return err;
 193 }
 194
 195 /*
 196  * parse entire mds reply
 197  */
 198 static int parse_reply_info(struct ceph_msg *msg,
 199                             struct ceph_mds_reply_info_parsed *info)
 200 {
 201         void *p, *end;
 202         u32 len;
 203         int err;
 204
 205         info->head = msg->front.iov_base;
 206         p = msg->front.iov_base + sizeof(struct ceph_mds_reply_head);
 207         end = p + msg->front.iov_len - sizeof(struct ceph_mds_reply_head);
 208
 209         /* trace */
 210         ceph_decode_32_safe(&p, end, len, bad);
 211         if (len > 0) {
 212                 err = parse_reply_info_trace(&p, p+len, info);
 213                 if (err < 0)
 214                         goto out_bad;
 215         }
 216
 217         /* dir content */
 218         ceph_decode_32_safe(&p, end, len, bad);
 219         if (len > 0) {
 220                 err = parse_reply_info_dir(&p, p+len, info);
 221                 if (err < 0)
 222                         goto out_bad;
 223         }
 224
 225         /* snap blob */
 226         ceph_decode_32_safe(&p, end, len, bad);
 227         info->snapblob_len = len;
 228         info->snapblob = p;
 229         p += len;
 230
 231         if (p != end)
 232                 goto bad;
 233         return 0;
 234
 235 bad:
 236         err = -EIO;
 237 out_bad:
 238         pr_err("mds parse_reply err %d\n", err);
 239         return err;
 240 }
 241
 242 static void destroy_reply_info(struct ceph_mds_reply_info_parsed *info)
 243 {
 244         kfree(info->dir_in);
 245 }
 246
 247
 248 /*
 249  * sessions
 250  */
 251 static const char *session_state_name(int s)
 252 {
 253         switch (s) {
 254         case CEPH_MDS_SESSION_NEW: return "new";
 255         case CEPH_MDS_SESSION_OPENING: return "opening";
 256         case CEPH_MDS_SESSION_OPEN: return "open";
 257         case CEPH_MDS_SESSION_HUNG: return "hung";
 258         case CEPH_MDS_SESSION_CLOSING: return "closing";
 259         case CEPH_MDS_SESSION_RESTARTING: return "restarting";
 260         case CEPH_MDS_SESSION_RECONNECTING: return "reconnecting";
 261         default: return "???";
 262         }
 263 }
 264
 265 static struct ceph_mds_session *get_session(struct ceph_mds_session *s)
 266 {
 267         if (atomic_inc_not_zero(&s->s_ref)) {
 268                 dout("mdsc get_session %p %d -> %d\n", s,
 269                      atomic_read(&s->s_ref)-1, atomic_read(&s->s_ref));
 270                 return s;
 271         } else {
 272                 dout("mdsc get_session %p 0 -- FAIL", s);
 273                 return NULL;
 274         }
 275 }
 276
 277 void ceph_put_mds_session(struct ceph_mds_session *s)
 278 {
 279         dout("mdsc put_session %p %d -> %d\n", s,
 280              atomic_read(&s->s_ref), atomic_read(&s->s_ref)-1);
 281         if (atomic_dec_and_test(&s->s_ref)) {
 282                 if (s->s_authorizer)
 283                         s->s_mdsc->client->monc.auth->ops->destroy_authorizer(
 284                                 s->s_mdsc->client->monc.auth, s->s_authorizer);
 285                 kfree(s);
 286         }
 287 }
 288
 289 /*
 290  * called under mdsc->mutex
 291  */
 292 struct ceph_mds_session *__ceph_lookup_mds_session(struct ceph_mds_client *mdsc,
 293                                                    int mds)
 294 {
 295         struct ceph_mds_session *session;
 296
 297         if (mds >= mdsc->max_sessions || mdsc->sessions[mds] == NULL)
 298                 return NULL;
 299         session = mdsc->sessions[mds];
 300         dout("lookup_mds_session %p %d\n", session,
 301              atomic_read(&session->s_ref));
 302         get_session(session);
 303         return session;
 304 }
 305
 306 static bool __have_session(struct ceph_mds_client *mdsc, int mds)
 307 {
 308         if (mds >= mdsc->max_sessions)
 309                 return false;
 310         return mdsc->sessions[mds];
 311 }
 312
 313 static int __verify_registered_session(struct ceph_mds_client *mdsc,
 314                                        struct ceph_mds_session *s)
 315 {
 316         if (s->s_mds >= mdsc->max_sessions ||
 317             mdsc->sessions[s->s_mds] != s)
 318                 return -ENOENT;
 319         return 0;
 320 }
 321
 322 /*
 323  * create+register a new session for given mds.
 324  * called under mdsc->mutex.
 325  */
 326 static struct ceph_mds_session *register_session(struct ceph_mds_client *mdsc,
 327                                                  int mds)
 328 {
 329         struct ceph_mds_session *s;
 330
 331         s = kzalloc(sizeof(*s), GFP_NOFS);
 332         if (!s)
 333                 return ERR_PTR(-ENOMEM);
 334         s->s_mdsc = mdsc;
 335         s->s_mds = mds;
 336         s->s_state = CEPH_MDS_SESSION_NEW;
 337         s->s_ttl = 0;
 338         s->s_seq = 0;
 339         mutex_init(&s->s_mutex);
 340
 341         ceph_con_init(mdsc->client->msgr, &s->s_con);
 342         s->s_con.private = s;
 343         s->s_con.ops = &mds_con_ops;
 344         s->s_con.peer_name.type = CEPH_ENTITY_TYPE_MDS;
 345         s->s_con.peer_name.num = cpu_to_le64(mds);
 346
 347         spin_lock_init(&s->s_cap_lock);
 348         s->s_cap_gen = 0;
 349         s->s_cap_ttl = 0;
 350         s->s_renew_requested = 0;
 351         s->s_renew_seq = 0;
 352         INIT_LIST_HEAD(&s->s_caps);
 353         s->s_nr_caps = 0;
 354         s->s_trim_caps = 0;
 355         atomic_set(&s->s_ref, 1);
 356         INIT_LIST_HEAD(&s->s_waiting);
 357         INIT_LIST_HEAD(&s->s_unsafe);
 358         s->s_num_cap_releases = 0;
 359         s->s_cap_iterator = NULL;
 360         INIT_LIST_HEAD(&s->s_cap_releases);
 361         INIT_LIST_HEAD(&s->s_cap_releases_done);
 362         INIT_LIST_HEAD(&s->s_cap_flushing);
 363         INIT_LIST_HEAD(&s->s_cap_snaps_flushing);
 364
 365         dout("register_session mds%d\n", mds);
 366         if (mds >= mdsc->max_sessions) {
 367                 int newmax = 1 << get_count_order(mds+1);
 368                 struct ceph_mds_session **sa;
 369
 370                 dout("register_session realloc to %d\n", newmax);
 371                 sa = kcalloc(newmax, sizeof(void *), GFP_NOFS);
 372                 if (sa == NULL)
 373                         goto fail_realloc;
 374                 if (mdsc->sessions) {
 375                         memcpy(sa, mdsc->sessions,
 376                                mdsc->max_sessions * sizeof(void *));
 377                         kfree(mdsc->sessions);
 378                 }
 379                 mdsc->sessions = sa;
 380                 mdsc->max_sessions = newmax;
 381         }
 382         mdsc->sessions[mds] = s;
 383         atomic_inc(&s->s_ref);  /* one ref to sessions[], one to caller */
 384
 385         ceph_con_open(&s->s_con, ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
 386
 387         return s;
 388
 389 fail_realloc:
 390         kfree(s);
 391         return ERR_PTR(-ENOMEM);
 392 }
 393
 394 /*
 395  * called under mdsc->mutex
 396  */
 397 static void __unregister_session(struct ceph_mds_client *mdsc,
 398                                struct ceph_mds_session *s)
 399 {
 400         dout("__unregister_session mds%d %p\n", s->s_mds, s);
 401         BUG_ON(mdsc->sessions[s->s_mds] != s);
 402         mdsc->sessions[s->s_mds] = NULL;
 403         ceph_con_close(&s->s_con);
 404         ceph_put_mds_session(s);
 405 }
 406
 407 /*
 408  * drop session refs in request.
 409  *
 410  * should be last request ref, or hold mdsc->mutex
 411  */
 412 static void put_request_session(struct ceph_mds_request *req)
 413 {
 414         if (req->r_session) {
 415                 ceph_put_mds_session(req->r_session);
 416                 req->r_session = NULL;
 417         }
 418 }
 419
 420 void ceph_mdsc_release_request(struct kref *kref)
 421 {
 422         struct ceph_mds_request *req = container_of(kref,
 423                                                     struct ceph_mds_request,
 424                                                     r_kref);
 425         if (req->r_request)
 426                 ceph_msg_put(req->r_request);
 427         if (req->r_reply) {
 428                 ceph_msg_put(req->r_reply);
 429                 destroy_reply_info(&req->r_reply_info);
 430         }
 431         if (req->r_inode) {
 432                 ceph_put_cap_refs(ceph_inode(req->r_inode),
 433                                   CEPH_CAP_PIN);
 434                 iput(req->r_inode);
 435         }
 436         if (req->r_locked_dir)
 437                 ceph_put_cap_refs(ceph_inode(req->r_locked_dir),
 438                                   CEPH_CAP_PIN);
 439         if (req->r_target_inode)
 440                 iput(req->r_target_inode);
 441         if (req->r_dentry)
 442                 dput(req->r_dentry);
 443         if (req->r_old_dentry) {
 444                 ceph_put_cap_refs(
 445                         ceph_inode(req->r_old_dentry->d_parent->d_inode),
 446                         CEPH_CAP_PIN);
 447                 dput(req->r_old_dentry);
 448         }
 449         kfree(req->r_path1);
 450         kfree(req->r_path2);
 451         put_request_session(req);
 452         ceph_unreserve_caps(&req->r_caps_reservation);
 453         kfree(req);
 454 }
 455
 456 /*
 457  * lookup session, bump ref if found.
 458  *
 459  * called under mdsc->mutex.
 460  */
 461 static struct ceph_mds_request *__lookup_request(struct ceph_mds_client *mdsc,
 462                                              u64 tid)
 463 {
 464         struct ceph_mds_request *req;
 465         struct rb_node *n = mdsc->request_tree.rb_node;
 466
 467         while (n) {
 468                 req = rb_entry(n, struct ceph_mds_request, r_node);
 469                 if (tid < req->r_tid)
 470                         n = n->rb_left;
 471                 else if (tid > req->r_tid)
 472                         n = n->rb_right;
 473                 else {
 474                         ceph_mdsc_get_request(req);
 475                         return req;
 476                 }
 477         }
 478         return NULL;
 479 }
 480
 481 static void __insert_request(struct ceph_mds_client *mdsc,
 482                              struct ceph_mds_request *new)
 483 {
 484         struct rb_node **p = &mdsc->request_tree.rb_node;
 485         struct rb_node *parent = NULL;
 486         struct ceph_mds_request *req = NULL;
 487
 488         while (*p) {
 489                 parent = *p;
 490                 req = rb_entry(parent, struct ceph_mds_request, r_node);
 491                 if (new->r_tid < req->r_tid)
 492                         p = &(*p)->rb_left;
 493                 else if (new->r_tid > req->r_tid)
 494                         p = &(*p)->rb_right;
 495                 else
 496                         BUG();
 497         }
 498
 499         rb_link_node(&new->r_node, parent, p);
 500         rb_insert_color(&new->r_node, &mdsc->request_tree);
 501 }
 502
 503 /*
 504  * Register an in-flight request, and assign a tid.  Link to directory
 505  * are modifying (if any).
 506  *
 507  * Called under mdsc->mutex.
 508  */
 509 static void __register_request(struct ceph_mds_client *mdsc,
 510                                struct ceph_mds_request *req,
 511                                struct inode *dir)
 512 {
 513         req->r_tid = ++mdsc->last_tid;
 514         if (req->r_num_caps)
 515                 ceph_reserve_caps(&req->r_caps_reservation, req->r_num_caps);
 516         dout("__register_request %p tid %lld\n", req, req->r_tid);
 517         ceph_mdsc_get_request(req);
 518         __insert_request(mdsc, req);
 519
 520         if (dir) {
 521                 struct ceph_inode_info *ci = ceph_inode(dir);
 522
 523                 spin_lock(&ci->i_unsafe_lock);
 524                 req->r_unsafe_dir = dir;
 525                 list_add_tail(&req->r_unsafe_dir_item, &ci->i_unsafe_dirops);
 526                 spin_unlock(&ci->i_unsafe_lock);
 527         }
 528 }
 529
 530 static void __unregister_request(struct ceph_mds_client *mdsc,
 531                                  struct ceph_mds_request *req)
 532 {
 533         dout("__unregister_request %p tid %lld\n", req, req->r_tid);
 534         rb_erase(&req->r_node, &mdsc->request_tree);
 535         RB_CLEAR_NODE(&req->r_node);
 536
 537         if (req->r_unsafe_dir) {
 538                 struct ceph_inode_info *ci = ceph_inode(req->r_unsafe_dir);
 539
 540                 spin_lock(&ci->i_unsafe_lock);
 541                 list_del_init(&req->r_unsafe_dir_item);
 542                 spin_unlock(&ci->i_unsafe_lock);
 543         }
 544
 545         ceph_mdsc_put_request(req);
 546 }
 547
 548 /*
 549  * Choose mds to send request to next.  If there is a hint set in the
 550  * request (e.g., due to a prior forward hint from the mds), use that.
 551  * Otherwise, consult frag tree and/or caps to identify the
 552  * appropriate mds.  If all else fails, choose randomly.
 553  *
 554  * Called under mdsc->mutex.
 555  */
 556 static int __choose_mds(struct ceph_mds_client *mdsc,
 557                         struct ceph_mds_request *req)
 558 {
 559         struct inode *inode;
 560         struct ceph_inode_info *ci;
 561         struct ceph_cap *cap;
 562         int mode = req->r_direct_mode;
 563         int mds = -1;
 564         u32 hash = req->r_direct_hash;
 565         bool is_hash = req->r_direct_is_hash;
 566
 567         /*
 568          * is there a specific mds we should try?  ignore hint if we have
 569          * no session and the mds is not up (active or recovering).
 570          */
 571         if (req->r_resend_mds >= 0 &&
 572             (__have_session(mdsc, req->r_resend_mds) ||
 573              ceph_mdsmap_get_state(mdsc->mdsmap, req->r_resend_mds) > 0)) {
 574                 dout("choose_mds using resend_mds mds%d\n",
 575                      req->r_resend_mds);
 576                 return req->r_resend_mds;
 577         }
 578
 579         if (mode == USE_RANDOM_MDS)
 580                 goto random;
 581
 582         inode = NULL;
 583         if (req->r_inode) {
 584                 inode = req->r_inode;
 585         } else if (req->r_dentry) {
 586                 if (req->r_dentry->d_inode) {
 587                         inode = req->r_dentry->d_inode;
 588                 } else {
 589                         inode = req->r_dentry->d_parent->d_inode;
 590                         hash = req->r_dentry->d_name.hash;
 591                         is_hash = true;
 592                 }
 593         }
 594         dout("__choose_mds %p is_hash=%d (%d) mode %d\n", inode, (int)is_hash,
 595              (int)hash, mode);
 596         if (!inode)
 597                 goto random;
 598         ci = ceph_inode(inode);
 599
 600         if (is_hash && S_ISDIR(inode->i_mode)) {
 601                 struct ceph_inode_frag frag;
 602                 int found;
 603
 604                 ceph_choose_frag(ci, hash, &frag, &found);
 605                 if (found) {
 606                         if (mode == USE_ANY_MDS && frag.ndist > 0) {
 607                                 u8 r;
 608
 609                                 /* choose a random replica */
 610                                 get_random_bytes(&r, 1);
 611                                 r %= frag.ndist;
 612                                 mds = frag.dist[r];
 613                                 dout("choose_mds %p %llx.%llx "
 614                                      "frag %u mds%d (%d/%d)\n",
 615                                      inode, ceph_vinop(inode),
 616                                      frag.frag, frag.mds,
 617                                      (int)r, frag.ndist);
 618                                 return mds;
 619                         }
 620
 621                         /* since this file/dir wasn't known to be
 622                          * replicated, then we want to look for the
 623                          * authoritative mds. */
 624                         mode = USE_AUTH_MDS;
 625                         if (frag.mds >= 0) {
 626                                 /* choose auth mds */
 627                                 mds = frag.mds;
 628                                 dout("choose_mds %p %llx.%llx "
 629                                      "frag %u mds%d (auth)\n",
 630                                      inode, ceph_vinop(inode), frag.frag, mds);
 631                                 return mds;
 632                         }
 633                 }
 634         }
 635
 636         spin_lock(&inode->i_lock);
 637         cap = NULL;
 638         if (mode == USE_AUTH_MDS)
 639                 cap = ci->i_auth_cap;
 640         if (!cap && !RB_EMPTY_ROOT(&ci->i_caps))
 641                 cap = rb_entry(rb_first(&ci->i_caps), struct ceph_cap, ci_node);
 642         if (!cap) {
 643                 spin_unlock(&inode->i_lock);
 644                 goto random;
 645         }
 646         mds = cap->session->s_mds;
 647         dout("choose_mds %p %llx.%llx mds%d (%scap %p)\n",
 648              inode, ceph_vinop(inode), mds,
 649              cap == ci->i_auth_cap ? "auth " : "", cap);
 650         spin_unlock(&inode->i_lock);
 651         return mds;
 652
 653 random:
 654         mds = ceph_mdsmap_get_random_mds(mdsc->mdsmap);
 655         dout("choose_mds chose random mds%d\n", mds);
 656         return mds;
 657 }
 658
 659
 660 /*
 661  * session messages
 662  */
 663 static struct ceph_msg *create_session_msg(u32 op, u64 seq)
 664 {
 665         struct ceph_msg *msg;
 666         struct ceph_mds_session_head *h;
 667
 668         msg = ceph_msg_new(CEPH_MSG_CLIENT_SESSION, sizeof(*h), 0, 0, NULL);
 669         if (IS_ERR(msg)) {
 670                 pr_err("create_session_msg ENOMEM creating msg\n");
 671                 return ERR_PTR(PTR_ERR(msg));
 672         }
 673         h = msg->front.iov_base;
 674         h->op = cpu_to_le32(op);
 675         h->seq = cpu_to_le64(seq);
 676         return msg;
 677 }
 678
 679 /*
 680  * send session open request.
 681  *
 682  * called under mdsc->mutex
 683  */
 684 static int __open_session(struct ceph_mds_client *mdsc,
 685                           struct ceph_mds_session *session)
 686 {
 687         struct ceph_msg *msg;
 688         int mstate;
 689         int mds = session->s_mds;
 690         int err = 0;
 691
 692         /* wait for mds to go active? */
 693         mstate = ceph_mdsmap_get_state(mdsc->mdsmap, mds);
 694         dout("open_session to mds%d (%s)\n", mds,
 695              ceph_mds_state_name(mstate));
 696         session->s_state = CEPH_MDS_SESSION_OPENING;
 697         session->s_renew_requested = jiffies;
 698
 699         /* send connect message */
 700         msg = create_session_msg(CEPH_SESSION_REQUEST_OPEN, session->s_seq);
 701         if (IS_ERR(msg)) {
 702                 err = PTR_ERR(msg);
 703                 goto out;
 704         }
 705         ceph_con_send(&session->s_con, msg);
 706
 707 out:
 708         return 0;
 709 }
 710
 711 /*
 712  * session caps
 713  */
 714
 715 /*
 716  * Free preallocated cap messages assigned to this session
 717  */
 718 static void cleanup_cap_releases(struct ceph_mds_session *session)
 719 {
 720         struct ceph_msg *msg;
 721
 722         spin_lock(&session->s_cap_lock);
 723         while (!list_empty(&session->s_cap_releases)) {
 724                 msg = list_first_entry(&session->s_cap_releases,
 725                                        struct ceph_msg, list_head);
 726                 list_del_init(&msg->list_head);
 727                 ceph_msg_put(msg);
 728         }
 729         while (!list_empty(&session->s_cap_releases_done)) {
 730                 msg = list_first_entry(&session->s_cap_releases_done,
 731                                        struct ceph_msg, list_head);
 732                 list_del_init(&msg->list_head);
 733                 ceph_msg_put(msg);
 734         }
 735         spin_unlock(&session->s_cap_lock);
 736 }
 737
 738 /*
 739  * Helper to safely iterate over all caps associated with a session, with
 740  * special care taken to handle a racing __ceph_remove_cap().
 741  *
 742  * Caller must hold session s_mutex.
 743  */
 744 static int iterate_session_caps(struct ceph_mds_session *session,
 745                                  int (*cb)(struct inode *, struct ceph_cap *,
 746                                             void *), void *arg)
 747 {
 748         struct list_head *p;
 749         struct ceph_cap *cap;
 750         struct inode *inode, *last_inode = NULL;
 751         struct ceph_cap *old_cap = NULL;
 752         int ret;
 753
 754         dout("iterate_session_caps %p mds%d\n", session, session->s_mds);
 755         spin_lock(&session->s_cap_lock);
 756         p = session->s_caps.next;
 757         while (p != &session->s_caps) {
 758                 cap = list_entry(p, struct ceph_cap, session_caps);
 759                 inode = igrab(&cap->ci->vfs_inode);
 760                 if (!inode) {
 761                         p = p->next;
 762                         continue;
 763                 }
 764                 session->s_cap_iterator = cap;
 765                 spin_unlock(&session->s_cap_lock);
 766
 767                 if (last_inode) {
 768                         iput(last_inode);
 769                         last_inode = NULL;
 770                 }
 771                 if (old_cap) {
 772                         ceph_put_cap(old_cap);
 773                         old_cap = NULL;
 774                 }
 775
 776                 ret = cb(inode, cap, arg);
 777                 last_inode = inode;
 778
 779                 spin_lock(&session->s_cap_lock);
 780                 p = p->next;
 781                 if (cap->ci == NULL) {
 782                         dout("iterate_session_caps  finishing cap %p removal\n",
 783                              cap);
 784                         BUG_ON(cap->session != session);
 785                         list_del_init(&cap->session_caps);
 786                         session->s_nr_caps--;
 787                         cap->session = NULL;
 788                         old_cap = cap;  /* put_cap it w/o locks held */
 789                 }
 790                 if (ret < 0)
 791                         goto out;
 792         }
 793         ret = 0;
 794 out:
 795         session->s_cap_iterator = NULL;
 796         spin_unlock(&session->s_cap_lock);
 797
 798         if (last_inode)
 799                 iput(last_inode);
 800         if (old_cap)
 801                 ceph_put_cap(old_cap);
 802
 803         return ret;
 804 }
 805
 806 static int remove_session_caps_cb(struct inode *inode, struct ceph_cap *cap,
 807                                    void *arg)
 808 {
 809         struct ceph_inode_info *ci = ceph_inode(inode);
 810         dout("removing cap %p, ci is %p, inode is %p\n",
 811              cap, ci, &ci->vfs_inode);
 812         ceph_remove_cap(cap);
 813         return 0;
 814 }
 815
 816 /*
 817  * caller must hold session s_mutex
 818  */
 819 static void remove_session_caps(struct ceph_mds_session *session)
 820 {
 821         dout("remove_session_caps on %p\n", session);
 822         iterate_session_caps(session, remove_session_caps_cb, NULL);
 823         BUG_ON(session->s_nr_caps > 0);
 824         cleanup_cap_releases(session);
 825 }
 826
 827 /*
 828  * wake up any threads waiting on this session's caps.  if the cap is
 829  * old (didn't get renewed on the client reconnect), remove it now.
 830  *
 831  * caller must hold s_mutex.
 832  */
 833 static int wake_up_session_cb(struct inode *inode, struct ceph_cap *cap,
 834                               void *arg)
 835 {
 836         struct ceph_inode_info *ci = ceph_inode(inode);
 837
 838         wake_up(&ci->i_cap_wq);
 839         if (arg) {
 840                 spin_lock(&inode->i_lock);
 841                 ci->i_wanted_max_size = 0;
 842                 ci->i_requested_max_size = 0;
 843                 spin_unlock(&inode->i_lock);
 844         }
 845         return 0;
 846 }
 847
 848 static void wake_up_session_caps(struct ceph_mds_session *session,
 849                                  int reconnect)
 850 {
 851         dout("wake_up_session_caps %p mds%d\n", session, session->s_mds);
 852         iterate_session_caps(session, wake_up_session_cb,
 853                              (void *)(unsigned long)reconnect);
 854 }
 855
 856 /*
 857  * Send periodic message to MDS renewing all currently held caps.  The
 858  * ack will reset the expiration for all caps from this session.
 859  *
 860  * caller holds s_mutex
 861  */
 862 static int send_renew_caps(struct ceph_mds_client *mdsc,
 863                            struct ceph_mds_session *session)
 864 {
 865         struct ceph_msg *msg;
 866         int state;
 867
 868         if (time_after_eq(jiffies, session->s_cap_ttl) &&
 869             time_after_eq(session->s_cap_ttl, session->s_renew_requested))
 870                 pr_info("mds%d caps stale\n", session->s_mds);
 871         session->s_renew_requested = jiffies;
 872
 873         /* do not try to renew caps until a recovering mds has reconnected
 874          * with its clients. */
 875         state = ceph_mdsmap_get_state(mdsc->mdsmap, session->s_mds);
 876         if (state < CEPH_MDS_STATE_RECONNECT) {
 877                 dout("send_renew_caps ignoring mds%d (%s)\n",
 878                      session->s_mds, ceph_mds_state_name(state));
 879                 return 0;
 880         }
 881
 882         dout("send_renew_caps to mds%d (%s)\n", session->s_mds,
 883                 ceph_mds_state_name(state));
 884         msg = create_session_msg(CEPH_SESSION_REQUEST_RENEWCAPS,
 885                                  ++session->s_renew_seq);
 886         if (IS_ERR(msg))
 887                 return PTR_ERR(msg);
 888         ceph_con_send(&session->s_con, msg);
 889         return 0;
 890 }
 891
 892 /*
 893  * Note new cap ttl, and any transition from stale -> not stale (fresh?).
 894  *
 895  * Called under session->s_mutex
 896  */
 897 static void renewed_caps(struct ceph_mds_client *mdsc,
 898                          struct ceph_mds_session *session, int is_renew)
 899 {
 900         int was_stale;
 901         int wake = 0;
 902
 903         spin_lock(&session->s_cap_lock);
 904         was_stale = is_renew && (session->s_cap_ttl == 0 ||
 905                                  time_after_eq(jiffies, session->s_cap_ttl));
 906
 907         session->s_cap_ttl = session->s_renew_requested +
 908                 mdsc->mdsmap->m_session_timeout*HZ;
 909
 910         if (was_stale) {
 911                 if (time_before(jiffies, session->s_cap_ttl)) {
 912                         pr_info("mds%d caps renewed\n", session->s_mds);
 913                         wake = 1;
 914                 } else {
 915                         pr_info("mds%d caps still stale\n", session->s_mds);
 916                 }
 917         }
 918         dout("renewed_caps mds%d ttl now %lu, was %s, now %s\n",
 919              session->s_mds, session->s_cap_ttl, was_stale ? "stale" : "fresh",
 920              time_before(jiffies, session->s_cap_ttl) ? "stale" : "fresh");
 921         spin_unlock(&session->s_cap_lock);
 922
 923         if (wake)
 924                 wake_up_session_caps(session, 0);
 925 }
 926
 927 /*
 928  * send a session close request
 929  */
 930 static int request_close_session(struct ceph_mds_client *mdsc,
 931                                  struct ceph_mds_session *session)
 932 {
 933         struct ceph_msg *msg;
 934         int err = 0;
 935
 936         dout("request_close_session mds%d state %s seq %lld\n",
 937              session->s_mds, session_state_name(session->s_state),
 938              session->s_seq);
 939         msg = create_session_msg(CEPH_SESSION_REQUEST_CLOSE, session->s_seq);
 940         if (IS_ERR(msg))
 941                 err = PTR_ERR(msg);
 942         else
 943                 ceph_con_send(&session->s_con, msg);
 944         return err;
 945 }
 946
 947 /*
 948  * Called with s_mutex held.
 949  */
 950 static int __close_session(struct ceph_mds_client *mdsc,
 951                          struct ceph_mds_session *session)
 952 {
 953         if (session->s_state >= CEPH_MDS_SESSION_CLOSING)
 954                 return 0;
 955         session->s_state = CEPH_MDS_SESSION_CLOSING;
 956         return request_close_session(mdsc, session);
 957 }
 958
 959 /*
 960  * Trim old(er) caps.
 961  *
 962  * Because we can't cache an inode without one or more caps, we do
 963  * this indirectly: if a cap is unused, we prune its aliases, at which
 964  * point the inode will hopefully get dropped to.
 965  *
 966  * Yes, this is a bit sloppy.  Our only real goal here is to respond to
 967  * memory pressure from the MDS, though, so it needn't be perfect.
 968  */
 969 static int trim_caps_cb(struct inode *inode, struct ceph_cap *cap, void *arg)
 970 {
 971         struct ceph_mds_session *session = arg;
 972         struct ceph_inode_info *ci = ceph_inode(inode);
 973         int used, oissued, mine;
 974
 975         if (session->s_trim_caps <= 0)
 976                 return -1;
 977
 978         spin_lock(&inode->i_lock);
 979         mine = cap->issued | cap->implemented;
 980         used = __ceph_caps_used(ci);
 981         oissued = __ceph_caps_issued_other(ci, cap);
 982
 983         dout("trim_caps_cb %p cap %p mine %s oissued %s used %s\n",
 984              inode, cap, ceph_cap_string(mine), ceph_cap_string(oissued),
 985              ceph_cap_string(used));
 986         if (ci->i_dirty_caps)
 987                 goto out;   /* dirty caps */
 988         if ((used & ~oissued) & mine)
 989                 goto out;   /* we need these caps */
 990
 991         session->s_trim_caps--;
 992         if (oissued) {
 993                 /* we aren't the only cap.. just remove us */
 994                 __ceph_remove_cap(cap);
 995         } else {
 996                 /* try to drop referring dentries */
 997                 spin_unlock(&inode->i_lock);
 998                 d_prune_aliases(inode);
 999                 dout("trim_caps_cb %p cap %p  pruned, count now %d\n",
1000                      inode, cap, atomic_read(&inode->i_count));
1001                 return 0;
1002         }
1003
1004 out:
1005         spin_unlock(&inode->i_lock);
1006         return 0;
1007 }
1008
1009 /*
1010  * Trim session cap count down to some max number.
1011  */
1012 static int trim_caps(struct ceph_mds_client *mdsc,
1013                      struct ceph_mds_session *session,
1014                      int max_caps)
1015 {
1016         int trim_caps = session->s_nr_caps - max_caps;
1017
1018         dout("trim_caps mds%d start: %d / %d, trim %d\n",
1019              session->s_mds, session->s_nr_caps, max_caps, trim_caps);
1020         if (trim_caps > 0) {
1021                 session->s_trim_caps = trim_caps;
1022                 iterate_session_caps(session, trim_caps_cb, session);
1023                 dout("trim_caps mds%d done: %d / %d, trimmed %d\n",
1024                      session->s_mds, session->s_nr_caps, max_caps,
1025                         trim_caps - session->s_trim_caps);
1026                 session->s_trim_caps = 0;
1027         }
1028         return 0;
1029 }
1030
1031 /*
1032  * Allocate cap_release messages.  If there is a partially full message
1033  * in the queue, try to allocate enough to cover it's remainder, so that
1034  * we can send it immediately.
1035  *
1036  * Called under s_mutex.
1037  */
1038 static int add_cap_releases(struct ceph_mds_client *mdsc,
1039                             struct ceph_mds_session *session,
1040                             int extra)
1041 {
1042         struct ceph_msg *msg;
1043         struct ceph_mds_cap_release *head;
1044         int err = -ENOMEM;
1045
1046         if (extra < 0)
1047                 extra = mdsc->client->mount_args->cap_release_safety;
1048
1049         spin_lock(&session->s_cap_lock);
1050
1051         if (!list_empty(&session->s_cap_releases)) {
1052                 msg = list_first_entry(&session->s_cap_releases,
1053                                        struct ceph_msg,
1054                                  list_head);
1055                 head = msg->front.iov_base;
1056                 extra += CEPH_CAPS_PER_RELEASE - le32_to_cpu(head->num);
1057         }
1058
1059         while (session->s_num_cap_releases < session->s_nr_caps + extra) {
1060                 spin_unlock(&session->s_cap_lock);
1061                 msg = ceph_msg_new(CEPH_MSG_CLIENT_CAPRELEASE, PAGE_CACHE_SIZE,
1062                                    0, 0, NULL);
1063                 if (!msg)
1064                         goto out_unlocked;
1065                 dout("add_cap_releases %p msg %p now %d\n", session, msg,
1066                      (int)msg->front.iov_len);
1067                 head = msg->front.iov_base;
1068                 head->num = cpu_to_le32(0);
1069                 msg->front.iov_len = sizeof(*head);
1070                 spin_lock(&session->s_cap_lock);
1071                 list_add(&msg->list_head, &session->s_cap_releases);
1072                 session->s_num_cap_releases += CEPH_CAPS_PER_RELEASE;
1073         }
1074
1075         if (!list_empty(&session->s_cap_releases)) {
1076                 msg = list_first_entry(&session->s_cap_releases,
1077                                        struct ceph_msg,
1078                                        list_head);
1079                 head = msg->front.iov_base;
1080                 if (head->num) {
1081                         dout(" queueing non-full %p (%d)\n", msg,
1082                              le32_to_cpu(head->num));
1083                         list_move_tail(&msg->list_head,
1084                                       &session->s_cap_releases_done);
1085                         session->s_num_cap_releases -=
1086                                 CEPH_CAPS_PER_RELEASE - le32_to_cpu(head->num);
1087                 }
1088         }
1089         err = 0;
1090         spin_unlock(&session->s_cap_lock);
1091 out_unlocked:
1092         return err;
1093 }
1094
1095 /*
1096  * flush all dirty inode data to disk.
1097  *
1098  * returns true if we've flushed through want_flush_seq
1099  */
1100 static int check_cap_flush(struct ceph_mds_client *mdsc, u64 want_flush_seq)
1101 {
1102         int mds, ret = 1;
1103
1104         dout("check_cap_flush want %lld\n", want_flush_seq);
1105         mutex_lock(&mdsc->mutex);
1106         for (mds = 0; ret && mds < mdsc->max_sessions; mds++) {
1107                 struct ceph_mds_session *session = mdsc->sessions[mds];
1108
1109                 if (!session)
1110                         continue;
1111                 get_session(session);
1112                 mutex_unlock(&mdsc->mutex);
1113
1114                 mutex_lock(&session->s_mutex);
1115                 if (!list_empty(&session->s_cap_flushing)) {
1116                         struct ceph_inode_info *ci =
1117                                 list_entry(session->s_cap_flushing.next,
1118                                            struct ceph_inode_info,
1119                                            i_flushing_item);
1120                         struct inode *inode = &ci->vfs_inode;
1121
1122                         spin_lock(&inode->i_lock);
1123                         if (ci->i_cap_flush_seq <= want_flush_seq) {
1124                                 dout("check_cap_flush still flushing %p "
1125                                      "seq %lld <= %lld to mds%d\n", inode,
1126                                      ci->i_cap_flush_seq, want_flush_seq,
1127                                      session->s_mds);
1128                                 ret = 0;
1129                         }
1130                         spin_unlock(&inode->i_lock);
1131                 }
1132                 mutex_unlock(&session->s_mutex);
1133                 ceph_put_mds_session(session);
1134
1135                 if (!ret)
1136                         return ret;
1137                 mutex_lock(&mdsc->mutex);
1138         }
1139
1140         mutex_unlock(&mdsc->mutex);
1141         dout("check_cap_flush ok, flushed thru %lld\n", want_flush_seq);
1142         return ret;
1143 }
1144
1145 /*
1146  * called under s_mutex
1147  */
1148 static void send_cap_releases(struct ceph_mds_client *mdsc,
1149                        struct ceph_mds_session *session)
1150 {
1151         struct ceph_msg *msg;
1152
1153         dout("send_cap_releases mds%d\n", session->s_mds);
1154         while (1) {
1155                 spin_lock(&session->s_cap_lock);
1156                 if (list_empty(&session->s_cap_releases_done))
1157                         break;
1158                 msg = list_first_entry(&session->s_cap_releases_done,
1159                                  struct ceph_msg, list_head);
1160                 list_del_init(&msg->list_head);
1161                 spin_unlock(&session->s_cap_lock);
1162                 msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
1163                 dout("send_cap_releases mds%d %p\n", session->s_mds, msg);
1164                 ceph_con_send(&session->s_con, msg);
1165         }
1166         spin_unlock(&session->s_cap_lock);
1167 }
1168
1169 /*
1170  * requests
1171  */
1172
1173 /*
1174  * Create an mds request.
1175  */
1176 struct ceph_mds_request *
1177 ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode)
1178 {
1179         struct ceph_mds_request *req = kzalloc(sizeof(*req), GFP_NOFS);
1180
1181         if (!req)
1182                 return ERR_PTR(-ENOMEM);
1183
1184         mutex_init(&req->r_fill_mutex);
1185         req->r_started = jiffies;
1186         req->r_resend_mds = -1;
1187         INIT_LIST_HEAD(&req->r_unsafe_dir_item);
1188         req->r_fmode = -1;
1189         kref_init(&req->r_kref);
1190         INIT_LIST_HEAD(&req->r_wait);
1191         init_completion(&req->r_completion);
1192         init_completion(&req->r_safe_completion);
1193         INIT_LIST_HEAD(&req->r_unsafe_item);
1194
1195         req->r_op = op;
1196         req->r_direct_mode = mode;
1197         return req;
1198 }
1199
1200 /*
1201  * return oldest (lowest) request, tid in request tree, 0 if none.
1202  *
1203  * called under mdsc->mutex.
1204  */
1205 static struct ceph_mds_request *__get_oldest_req(struct ceph_mds_client *mdsc)
1206 {
1207         if (RB_EMPTY_ROOT(&mdsc->request_tree))
1208                 return NULL;
1209         return rb_entry(rb_first(&mdsc->request_tree),
1210                         struct ceph_mds_request, r_node);
1211 }
1212
1213 static u64 __get_oldest_tid(struct ceph_mds_client *mdsc)
1214 {
1215         struct ceph_mds_request *req = __get_oldest_req(mdsc);
1216
1217         if (req)
1218                 return req->r_tid;
1219         return 0;
1220 }
1221
1222 /*
1223  * Build a dentry's path.  Allocate on heap; caller must kfree.  Based
1224  * on build_path_from_dentry in fs/cifs/dir.c.
1225  *
1226  * If @stop_on_nosnap, generate path relative to the first non-snapped
1227  * inode.
1228  *
1229  * Encode hidden .snap dirs as a double /, i.e.
1230  *   foo/.snap/bar -> foo//bar
1231  */
1232 char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *base,
1233                            int stop_on_nosnap)
1234 {
1235         struct dentry *temp;
1236         char *path;
1237         int len, pos;
1238
1239         if (dentry == NULL)
1240                 return ERR_PTR(-EINVAL);
1241
1242 retry:
1243         len = 0;
1244         for (temp = dentry; !IS_ROOT(temp);) {
1245                 struct inode *inode = temp->d_inode;
1246                 if (inode && ceph_snap(inode) == CEPH_SNAPDIR)
1247                         len++;  /* slash only */
1248                 else if (stop_on_nosnap && inode &&
1249                          ceph_snap(inode) == CEPH_NOSNAP)
1250                         break;
1251                 else
1252                         len += 1 + temp->d_name.len;
1253                 temp = temp->d_parent;
1254                 if (temp == NULL) {
1255                         pr_err("build_path_dentry corrupt dentry %p\n", dentry);
1256                         return ERR_PTR(-EINVAL);
1257                 }
1258         }
1259         if (len)
1260                 len--;  /* no leading '/' */
1261
1262         path = kmalloc(len+1, GFP_NOFS);
1263         if (path == NULL)
1264                 return ERR_PTR(-ENOMEM);
1265         pos = len;
1266         path[pos] = 0;  /* trailing null */
1267         for (temp = dentry; !IS_ROOT(temp) && pos != 0; ) {
1268                 struct inode *inode = temp->d_inode;
1269
1270                 if (inode && ceph_snap(inode) == CEPH_SNAPDIR) {
1271                         dout("build_path path+%d: %p SNAPDIR\n",
1272                              pos, temp);
1273                 } else if (stop_on_nosnap && inode &&
1274                            ceph_snap(inode) == CEPH_NOSNAP) {
1275                         break;
1276                 } else {
1277                         pos -= temp->d_name.len;
1278                         if (pos < 0)
1279                                 break;
1280                         strncpy(path + pos, temp->d_name.name,
1281                                 temp->d_name.len);
1282                 }
1283                 if (pos)
1284                         path[--pos] = '/';
1285                 temp = temp->d_parent;
1286                 if (temp == NULL) {
1287                         pr_err("build_path corrupt dentry\n");
1288                         kfree(path);
1289                         return ERR_PTR(-EINVAL);
1290                 }
1291         }
1292         if (pos != 0) {
1293                 pr_err("build_path did not end path lookup where "
1294                        "expected, namelen is %d, pos is %d\n", len, pos);
1295                 /* presumably this is only possible if racing with a
1296                    rename of one of the parent directories (we can not
1297                    lock the dentries above us to prevent this, but
1298                    retrying should be harmless) */
1299                 kfree(path);
1300                 goto retry;
1301         }
1302
1303         *base = ceph_ino(temp->d_inode);
1304         *plen = len;
1305         dout("build_path on %p %d built %llx '%.*s'\n",
1306              dentry, atomic_read(&dentry->d_count), *base, len, path);
1307         return path;
1308 }
1309
1310 static int build_dentry_path(struct dentry *dentry,
1311                              const char **ppath, int *ppathlen, u64 *pino,
1312                              int *pfreepath)
1313 {
1314         char *path;
1315
1316         if (ceph_snap(dentry->d_parent->d_inode) == CEPH_NOSNAP) {
1317                 *pino = ceph_ino(dentry->d_parent->d_inode);
1318                 *ppath = dentry->d_name.name;
1319                 *ppathlen = dentry->d_name.len;
1320                 return 0;
1321         }
1322         path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
1323         if (IS_ERR(path))
1324                 return PTR_ERR(path);
1325         *ppath = path;
1326         *pfreepath = 1;
1327         return 0;
1328 }
1329
1330 static int build_inode_path(struct inode *inode,
1331                             const char **ppath, int *ppathlen, u64 *pino,
1332                             int *pfreepath)
1333 {
1334         struct dentry *dentry;
1335         char *path;
1336
1337         if (ceph_snap(inode) == CEPH_NOSNAP) {
1338                 *pino = ceph_ino(inode);
1339                 *ppathlen = 0;
1340                 return 0;
1341         }
1342         dentry = d_find_alias(inode);
1343         path = ceph_mdsc_build_path(dentry, ppathlen, pino, 1);
1344         dput(dentry);
1345         if (IS_ERR(path))
1346                 return PTR_ERR(path);
1347         *ppath = path;
1348         *pfreepath = 1;
1349         return 0;
1350 }
1351
1352 /*
1353  * request arguments may be specified via an inode *, a dentry *, or
1354  * an explicit ino+path.
1355  */
1356 static int set_request_path_attr(struct inode *rinode, struct dentry *rdentry,
1357                                   const char *rpath, u64 rino,
1358                                   const char **ppath, int *pathlen,
1359                                   u64 *ino, int *freepath)
1360 {
1361         int r = 0;
1362
1363         if (rinode) {
1364                 r = build_inode_path(rinode, ppath, pathlen, ino, freepath);
1365                 dout(" inode %p %llx.%llx\n", rinode, ceph_ino(rinode),
1366                      ceph_snap(rinode));
1367         } else if (rdentry) {
1368                 r = build_dentry_path(rdentry, ppath, pathlen, ino, freepath);
1369                 dout(" dentry %p %llx/%.*s\n", rdentry, *ino, *pathlen,
1370                      *ppath);
1371         } else if (rpath) {
1372                 *ino = rino;
1373                 *ppath = rpath;
1374                 *pathlen = strlen(rpath);
1375                 dout(" path %.*s\n", *pathlen, rpath);
1376         }
1377
1378         return r;
1379 }
1380
1381 /*
1382  * called under mdsc->mutex
1383  */
1384 static struct ceph_msg *create_request_message(struct ceph_mds_client *mdsc,
1385                                                struct ceph_mds_request *req,
1386                                                int mds)
1387 {
1388         struct ceph_msg *msg;
1389         struct ceph_mds_request_head *head;
1390         const char *path1 = NULL;
1391         const char *path2 = NULL;
1392         u64 ino1 = 0, ino2 = 0;
1393         int pathlen1 = 0, pathlen2 = 0;
1394         int freepath1 = 0, freepath2 = 0;
1395         int len;
1396         u16 releases;
1397         void *p, *end;
1398         int ret;
1399
1400         ret = set_request_path_attr(req->r_inode, req->r_dentry,
1401                               req->r_path1, req->r_ino1.ino,
1402                               &path1, &pathlen1, &ino1, &freepath1);
1403         if (ret < 0) {
1404                 msg = ERR_PTR(ret);
1405                 goto out;
1406         }
1407
1408         ret = set_request_path_attr(NULL, req->r_old_dentry,
1409                               req->r_path2, req->r_ino2.ino,
1410                               &path2, &pathlen2, &ino2, &freepath2);
1411         if (ret < 0) {
1412                 msg = ERR_PTR(ret);
1413                 goto out_free1;
1414         }
1415
1416         len = sizeof(*head) +
1417                 pathlen1 + pathlen2 + 2*(1 + sizeof(u32) + sizeof(u64));
1418
1419         /* calculate (max) length for cap releases */
1420         len += sizeof(struct ceph_mds_request_release) *
1421                 (!!req->r_inode_drop + !!req->r_dentry_drop +
1422                  !!req->r_old_inode_drop + !!req->r_old_dentry_drop);
1423         if (req->r_dentry_drop)
1424                 len += req->r_dentry->d_name.len;
1425         if (req->r_old_dentry_drop)
1426                 len += req->r_old_dentry->d_name.len;
1427
1428         msg = ceph_msg_new(CEPH_MSG_CLIENT_REQUEST, len, 0, 0, NULL);
1429         if (IS_ERR(msg))
1430                 goto out_free2;
1431
1432         msg->hdr.tid = cpu_to_le64(req->r_tid);
1433
1434         head = msg->front.iov_base;
1435         p = msg->front.iov_base + sizeof(*head);
1436         end = msg->front.iov_base + msg->front.iov_len;
1437
1438         head->mdsmap_epoch = cpu_to_le32(mdsc->mdsmap->m_epoch);
1439         head->op = cpu_to_le32(req->r_op);
1440         head->caller_uid = cpu_to_le32(current_fsuid());
1441         head->caller_gid = cpu_to_le32(current_fsgid());
1442         head->args = req->r_args;
1443
1444         ceph_encode_filepath(&p, end, ino1, path1);
1445         ceph_encode_filepath(&p, end, ino2, path2);
1446
1447         /* cap releases */
1448         releases = 0;
1449         if (req->r_inode_drop)
1450                 releases += ceph_encode_inode_release(&p,
1451                       req->r_inode ? req->r_inode : req->r_dentry->d_inode,
1452                       mds, req->r_inode_drop, req->r_inode_unless, 0);
1453         if (req->r_dentry_drop)
1454                 releases += ceph_encode_dentry_release(&p, req->r_dentry,
1455                        mds, req->r_dentry_drop, req->r_dentry_unless);
1456         if (req->r_old_dentry_drop)
1457                 releases += ceph_encode_dentry_release(&p, req->r_old_dentry,
1458                        mds, req->r_old_dentry_drop, req->r_old_dentry_unless);
1459         if (req->r_old_inode_drop)
1460                 releases += ceph_encode_inode_release(&p,
1461                       req->r_old_dentry->d_inode,
1462                       mds, req->r_old_inode_drop, req->r_old_inode_unless, 0);
1463         head->num_releases = cpu_to_le16(releases);
1464
1465         BUG_ON(p > end);
1466         msg->front.iov_len = p - msg->front.iov_base;
1467         msg->hdr.front_len = cpu_to_le32(msg->front.iov_len);
1468
1469         msg->pages = req->r_pages;
1470         msg->nr_pages = req->r_num_pages;
1471         msg->hdr.data_len = cpu_to_le32(req->r_data_len);
1472         msg->hdr.data_off = cpu_to_le16(0);
1473
1474 out_free2:
1475         if (freepath2)
1476                 kfree((char *)path2);
1477 out_free1:
1478         if (freepath1)
1479                 kfree((char *)path1);
1480 out:
1481         return msg;
1482 }
1483
1484 /*
1485  * called under mdsc->mutex if error, under no mutex if
1486  * success.
1487  */
1488 static void complete_request(struct ceph_mds_client *mdsc,
1489                              struct ceph_mds_request *req)
1490 {
1491         if (req->r_callback)
1492                 req->r_callback(mdsc, req);
1493         else
1494                 complete(&req->r_completion);
1495 }
1496
1497 /*
1498  * called under mdsc->mutex
1499  */
1500 static int __prepare_send_request(struct ceph_mds_client *mdsc,
1501                                   struct ceph_mds_request *req,
1502                                   int mds)
1503 {
1504         struct ceph_mds_request_head *rhead;
1505         struct ceph_msg *msg;
1506         int flags = 0;
1507
1508         req->r_mds = mds;
1509         req->r_attempts++;
1510         dout("prepare_send_request %p tid %lld %s (attempt %d)\n", req,
1511              req->r_tid, ceph_mds_op_name(req->r_op), req->r_attempts);
1512
1513         if (req->r_request) {
1514                 ceph_msg_put(req->r_request);
1515                 req->r_request = NULL;
1516         }
1517         msg = create_request_message(mdsc, req, mds);
1518         if (IS_ERR(msg)) {
1519                 req->r_err = PTR_ERR(msg);
1520                 complete_request(mdsc, req);
1521                 return -PTR_ERR(msg);
1522         }
1523         req->r_request = msg;
1524
1525         rhead = msg->front.iov_base;
1526         rhead->oldest_client_tid = cpu_to_le64(__get_oldest_tid(mdsc));
1527         if (req->r_got_unsafe)
1528                 flags |= CEPH_MDS_FLAG_REPLAY;
1529         if (req->r_locked_dir)
1530                 flags |= CEPH_MDS_FLAG_WANT_DENTRY;
1531         rhead->flags = cpu_to_le32(flags);
1532         rhead->num_fwd = req->r_num_fwd;
1533         rhead->num_retry = req->r_attempts - 1;
1534
1535         dout(" r_locked_dir = %p\n", req->r_locked_dir);
1536
1537         if (req->r_target_inode && req->r_got_unsafe)
1538                 rhead->ino = cpu_to_le64(ceph_ino(req->r_target_inode));
1539         else
1540                 rhead->ino = 0;
1541         return 0;
1542 }
1543
1544 /*
1545  * send request, or put it on the appropriate wait list.
1546  */
1547 static int __do_request(struct ceph_mds_client *mdsc,
1548                         struct ceph_mds_request *req)
1549 {
1550         struct ceph_mds_session *session = NULL;
1551         int mds = -1;
1552         int err = -EAGAIN;
1553
1554         if (req->r_err || req->r_got_result)
1555                 goto out;
1556
1557         if (req->r_timeout &&
1558             time_after_eq(jiffies, req->r_started + req->r_timeout)) {
1559                 dout("do_request timed out\n");
1560                 err = -EIO;
1561                 goto finish;
1562         }
1563
1564         mds = __choose_mds(mdsc, req);
1565         if (mds < 0 ||
1566             ceph_mdsmap_get_state(mdsc->mdsmap, mds) < CEPH_MDS_STATE_ACTIVE) {
1567                 dout("do_request no mds or not active, waiting for map\n");
1568                 list_add(&req->r_wait, &mdsc->waiting_for_map);
1569                 goto out;
1570         }
1571
1572         /* get, open session */
1573         session = __ceph_lookup_mds_session(mdsc, mds);
1574         if (!session) {
1575                 session = register_session(mdsc, mds);
1576                 if (IS_ERR(session)) {
1577                         err = PTR_ERR(session);
1578                         goto finish;
1579                 }
1580         }
1581         dout("do_request mds%d session %p state %s\n", mds, session,
1582              session_state_name(session->s_state));
1583         if (session->s_state != CEPH_MDS_SESSION_OPEN &&
1584             session->s_state != CEPH_MDS_SESSION_HUNG) {
1585                 if (session->s_state == CEPH_MDS_SESSION_NEW ||
1586                     session->s_state == CEPH_MDS_SESSION_CLOSING)
1587                         __open_session(mdsc, session);
1588                 list_add(&req->r_wait, &session->s_waiting);
1589                 goto out_session;
1590         }
1591
1592         /* send request */
1593         req->r_session = get_session(session);
1594         req->r_resend_mds = -1;   /* forget any previous mds hint */
1595
1596         if (req->r_request_started == 0)   /* note request start time */
1597                 req->r_request_started = jiffies;
1598
1599         err = __prepare_send_request(mdsc, req, mds);
1600         if (!err) {
1601                 ceph_msg_get(req->r_request);
1602                 ceph_con_send(&session->s_con, req->r_request);
1603         }
1604
1605 out_session:
1606         ceph_put_mds_session(session);
1607 out:
1608         return err;
1609
1610 finish:
1611         req->r_err = err;
1612         complete_request(mdsc, req);
1613         goto out;
1614 }
1615
1616 /*
1617  * called under mdsc->mutex
1618  */
1619 static void __wake_requests(struct ceph_mds_client *mdsc,
1620                             struct list_head *head)
1621 {
1622         struct ceph_mds_request *req, *nreq;
1623
1624         list_for_each_entry_safe(req, nreq, head, r_wait) {
1625                 list_del_init(&req->r_wait);
1626                 __do_request(mdsc, req);
1627         }
1628 }
1629
1630 /*
1631  * Wake up threads with requests pending for @mds, so that they can
1632  * resubmit their requests to a possibly different mds.  If @all is set,
1633  * wake up if their requests has been forwarded to @mds, too.
1634  */
1635 static void kick_requests(struct ceph_mds_client *mdsc, int mds, int all)
1636 {
1637         struct ceph_mds_request *req;
1638         struct rb_node *p;
1639
1640         dout("kick_requests mds%d\n", mds);
1641         for (p = rb_first(&mdsc->request_tree); p; p = rb_next(p)) {
1642                 req = rb_entry(p, struct ceph_mds_request, r_node);
1643                 if (req->r_got_unsafe)
1644                         continue;
1645                 if (req->r_session &&
1646                     req->r_session->s_mds == mds) {
1647                         dout(" kicking tid %llu\n", req->r_tid);
1648                         put_request_session(req);
1649                         __do_request(mdsc, req);
1650                 }
1651         }
1652 }
1653
1654 void ceph_mdsc_submit_request(struct ceph_mds_client *mdsc,
1655                               struct ceph_mds_request *req)
1656 {
1657         dout("submit_request on %p\n", req);
1658         mutex_lock(&mdsc->mutex);
1659         __register_request(mdsc, req, NULL);
1660         __do_request(mdsc, req);
1661         mutex_unlock(&mdsc->mutex);
1662 }
1663
1664 /*
1665  * Synchrously perform an mds request.  Take care of all of the
1666  * session setup, forwarding, retry details.
1667  */
1668 int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
1669                          struct inode *dir,
1670                          struct ceph_mds_request *req)
1671 {
1672         int err;
1673
1674         dout("do_request on %p\n", req);
1675
1676         /* take CAP_PIN refs for r_inode, r_locked_dir, r_old_dentry */
1677         if (req->r_inode)
1678                 ceph_get_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN);
1679         if (req->r_locked_dir)
1680                 ceph_get_cap_refs(ceph_inode(req->r_locked_dir), CEPH_CAP_PIN);
1681         if (req->r_old_dentry)
1682                 ceph_get_cap_refs(
1683                         ceph_inode(req->r_old_dentry->d_parent->d_inode),
1684                         CEPH_CAP_PIN);
1685
1686         /* issue */
1687         mutex_lock(&mdsc->mutex);
1688         __register_request(mdsc, req, dir);
1689         __do_request(mdsc, req);
1690
1691         if (req->r_err) {
1692                 err = req->r_err;
1693                 __unregister_request(mdsc, req);
1694                 dout("do_request early error %d\n", err);
1695                 goto out;
1696         }
1697
1698         /* wait */
1699         mutex_unlock(&mdsc->mutex);
1700         dout("do_request waiting\n");
1701         if (req->r_timeout) {
1702                 err = (long)wait_for_completion_interruptible_timeout(
1703                         &req->r_completion, req->r_timeout);
1704                 if (err == 0)
1705                         err = -EIO;
1706         } else {
1707                 err = wait_for_completion_interruptible(&req->r_completion);
1708         }
1709         dout("do_request waited, got %d\n", err);
1710         mutex_lock(&mdsc->mutex);
1711
1712         /* only abort if we didn't race with a real reply */
1713         if (req->r_got_result) {
1714                 err = le32_to_cpu(req->r_reply_info.head->result);
1715         } else if (err < 0) {
1716                 dout("aborted request %lld with %d\n", req->r_tid, err);
1717
1718                 /*
1719                  * ensure we aren't running concurrently with
1720                  * ceph_fill_trace or ceph_readdir_prepopulate, which
1721                  * rely on locks (dir mutex) held by our caller.
1722                  */
1723                 mutex_lock(&req->r_fill_mutex);
1724                 req->r_err = err;
1725                 req->r_aborted = true;
1726                 mutex_unlock(&req->r_fill_mutex);
1727
1728                 if (req->r_locked_dir &&
1729                     (req->r_op & CEPH_MDS_OP_WRITE)) {
1730                         struct ceph_inode_info *ci =
1731                                 ceph_inode(req->r_locked_dir);
1732
1733                         dout("aborted, clearing I_COMPLETE on %p, leases\n",
1734                              req->r_locked_dir);
1735                         spin_lock(&req->r_locked_dir->i_lock);
1736                         ci->i_ceph_flags &= ~CEPH_I_COMPLETE;
1737                         ci->i_release_count++;
1738                         spin_unlock(&req->r_locked_dir->i_lock);
1739
1740                         if (req->r_dentry)
1741                                 ceph_invalidate_dentry_lease(req->r_dentry);
1742                         if (req->r_old_dentry)
1743                                 ceph_invalidate_dentry_lease(req->r_old_dentry);
1744                 }
1745         } else {
1746                 err = req->r_err;
1747         }
1748
1749 out:
1750         mutex_unlock(&mdsc->mutex);
1751         dout("do_request %p done, result %d\n", req, err);
1752         return err;
1753 }
1754
1755 /*
1756  * Handle mds reply.
1757  *
1758  * We take the session mutex and parse and process the reply immediately.
1759  * This preserves the logical ordering of replies, capabilities, etc., sent
1760  * by the MDS as they are applied to our local cache.
1761  */
1762 static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg)
1763 {
1764         struct ceph_mds_client *mdsc = session->s_mdsc;
1765         struct ceph_mds_request *req;
1766         struct ceph_mds_reply_head *head = msg->front.iov_base;
1767         struct ceph_mds_reply_info_parsed *rinfo;  /* parsed reply info */
1768         u64 tid;
1769         int err, result;
1770         int mds = session->s_mds;
1771
1772         if (msg->front.iov_len < sizeof(*head)) {
1773                 pr_err("mdsc_handle_reply got corrupt (short) reply\n");
1774                 ceph_msg_dump(msg);
1775                 return;
1776         }
1777
1778         /* get request, session */
1779         tid = le64_to_cpu(msg->hdr.tid);
1780         mutex_lock(&mdsc->mutex);
1781         req = __lookup_request(mdsc, tid);
1782         if (!req) {
1783                 dout("handle_reply on unknown tid %llu\n", tid);
1784                 mutex_unlock(&mdsc->mutex);
1785                 return;
1786         }
1787         dout("handle_reply %p\n", req);
1788
1789         /* correct session? */
1790         if (req->r_session != session) {
1791                 pr_err("mdsc_handle_reply got %llu on session mds%d"
1792                        " not mds%d\n", tid, session->s_mds,
1793                        req->r_session ? req->r_session->s_mds : -1);
1794                 mutex_unlock(&mdsc->mutex);
1795                 goto out;
1796         }
1797
1798         /* dup? */
1799         if ((req->r_got_unsafe && !head->safe) ||
1800             (req->r_got_safe && head->safe)) {
1801                 pr_warning("got a dup %s reply on %llu from mds%d\n",
1802                            head->safe ? "safe" : "unsafe", tid, mds);
1803                 mutex_unlock(&mdsc->mutex);
1804                 goto out;
1805         }
1806
1807         result = le32_to_cpu(head->result);
1808
1809         /*
1810          * Tolerate 2 consecutive ESTALEs from the same mds.
1811          * FIXME: we should be looking at the cap migrate_seq.
1812          */
1813         if (result == -ESTALE) {
1814                 req->r_direct_mode = USE_AUTH_MDS;
1815                 req->r_num_stale++;
1816                 if (req->r_num_stale <= 2) {
1817                         __do_request(mdsc, req);
1818                         mutex_unlock(&mdsc->mutex);
1819                         goto out;
1820                 }
1821         } else {
1822                 req->r_num_stale = 0;
1823         }
1824
1825         if (head->safe) {
1826                 req->r_got_safe = true;
1827                 __unregister_request(mdsc, req);
1828                 complete(&req->r_safe_completion);
1829
1830                 if (req->r_got_unsafe) {
1831                         /*
1832                          * We already handled the unsafe response, now do the
1833                          * cleanup.  No need to examine the response; the MDS
1834                          * doesn't include any result info in the safe
1835                          * response.  And even if it did, there is nothing
1836                          * useful we could do with a revised return value.
1837                          */
1838                         dout("got safe reply %llu, mds%d\n", tid, mds);
1839                         list_del_init(&req->r_unsafe_item);
1840
1841                         /* last unsafe request during umount? */
1842                         if (mdsc->stopping && !__get_oldest_req(mdsc))
1843                                 complete(&mdsc->safe_umount_waiters);
1844                         mutex_unlock(&mdsc->mutex);
1845                         goto out;
1846                 }
1847         } else {
1848                 req->r_got_unsafe = true;
1849                 list_add_tail(&req->r_unsafe_item, &req->r_session->s_unsafe);
1850         }
1851
1852         dout("handle_reply tid %lld result %d\n", tid, result);
1853         rinfo = &req->r_reply_info;
1854         err = parse_reply_info(msg, rinfo);
1855         mutex_unlock(&mdsc->mutex);
1856
1857         mutex_lock(&session->s_mutex);
1858         if (err < 0) {
1859                 pr_err("mdsc_handle_reply got corrupt reply mds%d\n", mds);
1860                 ceph_msg_dump(msg);
1861                 goto out_err;
1862         }
1863
1864         /* snap trace */
1865         if (rinfo->snapblob_len) {
1866                 down_write(&mdsc->snap_rwsem);
1867                 ceph_update_snap_trace(mdsc, rinfo->snapblob,
1868                                rinfo->snapblob + rinfo->snapblob_len,
1869                                le32_to_cpu(head->op) == CEPH_MDS_OP_RMSNAP);
1870                 downgrade_write(&mdsc->snap_rwsem);
1871         } else {
1872                 down_read(&mdsc->snap_rwsem);
1873         }
1874
1875         /* insert trace into our cache */
1876         mutex_lock(&req->r_fill_mutex);
1877         err = ceph_fill_trace(mdsc->client->sb, req, req->r_session);
1878         if (err == 0) {
1879                 if (result == 0 && rinfo->dir_nr)
1880                         ceph_readdir_prepopulate(req, req->r_session);
1881                 ceph_unreserve_caps(&req->r_caps_reservation);
1882         }
1883         mutex_unlock(&req->r_fill_mutex);
1884
1885         up_read(&mdsc->snap_rwsem);
1886 out_err:
1887         mutex_lock(&mdsc->mutex);
1888         if (!req->r_aborted) {
1889                 if (err) {
1890                         req->r_err = err;
1891                 } else {
1892                         req->r_reply = msg;
1893                         ceph_msg_get(msg);
1894                         req->r_got_result = true;
1895                 }
1896         } else {
1897                 dout("reply arrived after request %lld was aborted\n", tid);
1898         }
1899         mutex_unlock(&mdsc->mutex);
1900
1901         add_cap_releases(mdsc, req->r_session, -1);
1902         mutex_unlock(&session->s_mutex);
1903
1904         /* kick calling process */
1905         complete_request(mdsc, req);
1906 out:
1907         ceph_mdsc_put_request(req);
1908         return;
1909 }
1910
1911
1912
1913 /*
1914  * handle mds notification that our request has been forwarded.
1915  */
1916 static void handle_forward(struct ceph_mds_client *mdsc,
1917                            struct ceph_mds_session *session,
1918                            struct ceph_msg *msg)
1919 {
1920         struct ceph_mds_request *req;
1921         u64 tid = le64_to_cpu(msg->hdr.tid);
1922         u32 next_mds;
1923         u32 fwd_seq;
1924         int err = -EINVAL;
1925         void *p = msg->front.iov_base;
1926         void *end = p + msg->front.iov_len;
1927
1928         ceph_decode_need(&p, end, 2*sizeof(u32), bad);
1929         next_mds = ceph_decode_32(&p);
1930         fwd_seq = ceph_decode_32(&p);
1931
1932         mutex_lock(&mdsc->mutex);
1933         req = __lookup_request(mdsc, tid);
1934         if (!req) {
1935                 dout("forward %llu to mds%d - req dne\n", tid, next_mds);
1936                 goto out;  /* dup reply? */
1937         }
1938
1939         if (fwd_seq <= req->r_num_fwd) {
1940                 dout("forward %llu to mds%d - old seq %d <= %d\n",
1941                      tid, next_mds, req->r_num_fwd, fwd_seq);
1942         } else {
1943                 /* resend. forward race not possible; mds would drop */
1944                 dout("forward %llu to mds%d (we resend)\n", tid, next_mds);
1945                 req->r_num_fwd = fwd_seq;
1946                 req->r_resend_mds = next_mds;
1947                 put_request_session(req);
1948                 __do_request(mdsc, req);
1949         }
1950         ceph_mdsc_put_request(req);
1951 out:
1952         mutex_unlock(&mdsc->mutex);
1953         return;
1954
1955 bad:
1956         pr_err("mdsc_handle_forward decode error err=%d\n", err);
1957 }
1958
1959 /*
1960  * handle a mds session control message
1961  */
1962 static void handle_session(struct ceph_mds_session *session,
1963                            struct ceph_msg *msg)
1964 {
1965         struct ceph_mds_client *mdsc = session->s_mdsc;
1966         u32 op;
1967         u64 seq;
1968         int mds = session->s_mds;
1969         struct ceph_mds_session_head *h = msg->front.iov_base;
1970         int wake = 0;
1971
1972         /* decode */
1973         if (msg->front.iov_len != sizeof(*h))
1974                 goto bad;
1975         op = le32_to_cpu(h->op);
1976         seq = le64_to_cpu(h->seq);
1977
1978         mutex_lock(&mdsc->mutex);
1979         if (op == CEPH_SESSION_CLOSE)
1980                 __unregister_session(mdsc, session);
1981         /* FIXME: this ttl calculation is generous */
1982         session->s_ttl = jiffies + HZ*mdsc->mdsmap->m_session_autoclose;
1983         mutex_unlock(&mdsc->mutex);
1984
1985         mutex_lock(&session->s_mutex);
1986
1987         dout("handle_session mds%d %s %p state %s seq %llu\n",
1988              mds, ceph_session_op_name(op), session,
1989              session_state_name(session->s_state), seq);
1990
1991         if (session->s_state == CEPH_MDS_SESSION_HUNG) {
1992                 session->s_state = CEPH_MDS_SESSION_OPEN;
1993                 pr_info("mds%d came back\n", session->s_mds);
1994         }
1995
1996         switch (op) {
1997         case CEPH_SESSION_OPEN:
1998                 session->s_state = CEPH_MDS_SESSION_OPEN;
1999                 renewed_caps(mdsc, session, 0);
2000                 wake = 1;
2001                 if (mdsc->stopping)
2002                         __close_session(mdsc, session);
2003                 break;
2004
2005         case CEPH_SESSION_RENEWCAPS:
2006                 if (session->s_renew_seq == seq)
2007                         renewed_caps(mdsc, session, 1);
2008                 break;
2009
2010         case CEPH_SESSION_CLOSE:
2011                 remove_session_caps(session);
2012                 wake = 1; /* for good measure */
2013                 complete(&mdsc->session_close_waiters);
2014                 kick_requests(mdsc, mds, 0);      /* cur only */
2015                 break;
2016
2017         case CEPH_SESSION_STALE:
2018                 pr_info("mds%d caps went stale, renewing\n",
2019                         session->s_mds);
2020                 spin_lock(&session->s_cap_lock);
2021                 session->s_cap_gen++;
2022                 session->s_cap_ttl = 0;
2023                 spin_unlock(&session->s_cap_lock);
2024                 send_renew_caps(mdsc, session);
2025                 break;
2026
2027         case CEPH_SESSION_RECALL_STATE:
2028                 trim_caps(mdsc, session, le32_to_cpu(h->max_caps));
2029                 break;
2030
2031         default:
2032                 pr_err("mdsc_handle_session bad op %d mds%d\n", op, mds);
2033                 WARN_ON(1);
2034         }
2035
2036         mutex_unlock(&session->s_mutex);
2037         if (wake) {
2038                 mutex_lock(&mdsc->mutex);
2039                 __wake_requests(mdsc, &session->s_waiting);
2040                 mutex_unlock(&mdsc->mutex);
2041         }
2042         return;
2043
2044 bad:
2045         pr_err("mdsc_handle_session corrupt message mds%d len %d\n", mds,
2046                (int)msg->front.iov_len);
2047         ceph_msg_dump(msg);
2048         return;
2049 }
2050
2051
2052 /*
2053  * called under session->mutex.
2054  */
2055 static void replay_unsafe_requests(struct ceph_mds_client *mdsc,
2056                                    struct ceph_mds_session *session)
2057 {
2058         struct ceph_mds_request *req, *nreq;
2059         int err;
2060
2061         dout("replay_unsafe_requests mds%d\n", session->s_mds);
2062
2063         mutex_lock(&mdsc->mutex);
2064         list_for_each_entry_safe(req, nreq, &session->s_unsafe, r_unsafe_item) {
2065                 err = __prepare_send_request(mdsc, req, session->s_mds);
2066                 if (!err) {
2067                         ceph_msg_get(req->r_request);
2068                         ceph_con_send(&session->s_con, req->r_request);
2069                 }
2070         }
2071         mutex_unlock(&mdsc->mutex);
2072 }
2073
2074 /*
2075  * Encode information about a cap for a reconnect with the MDS.
2076  */
2077 static int encode_caps_cb(struct inode *inode, struct ceph_cap *cap,
2078                           void *arg)
2079 {
2080         struct ceph_mds_cap_reconnect rec;
2081         struct ceph_inode_info *ci;
2082         struct ceph_pagelist *pagelist = arg;
2083         char *path;
2084         int pathlen, err;
2085         u64 pathbase;
2086         struct dentry *dentry;
2087
2088         ci = cap->ci;
2089
2090         dout(" adding %p ino %llx.%llx cap %p %lld %s\n",
2091              inode, ceph_vinop(inode), cap, cap->cap_id,
2092              ceph_cap_string(cap->issued));
2093         err = ceph_pagelist_encode_64(pagelist, ceph_ino(inode));
2094         if (err)
2095                 return err;
2096
2097         dentry = d_find_alias(inode);
2098         if (dentry) {
2099                 path = ceph_mdsc_build_path(dentry, &pathlen, &pathbase, 0);
2100                 if (IS_ERR(path)) {
2101                         err = PTR_ERR(path);
2102                         BUG_ON(err);
2103                 }
2104         } else {
2105                 path = NULL;
2106                 pathlen = 0;
2107         }
2108         err = ceph_pagelist_encode_string(pagelist, path, pathlen);
2109         if (err)
2110                 goto out;
2111
2112         spin_lock(&inode->i_lock);
2113         cap->seq = 0;        /* reset cap seq */
2114         cap->issue_seq = 0;  /* and issue_seq */
2115         rec.cap_id = cpu_to_le64(cap->cap_id);
2116         rec.pathbase = cpu_to_le64(pathbase);
2117         rec.wanted = cpu_to_le32(__ceph_caps_wanted(ci));
2118         rec.issued = cpu_to_le32(cap->issued);
2119         rec.size = cpu_to_le64(inode->i_size);
2120         ceph_encode_timespec(&rec.mtime, &inode->i_mtime);
2121         ceph_encode_timespec(&rec.atime, &inode->i_atime);
2122         rec.snaprealm = cpu_to_le64(ci->i_snap_realm->ino);
2123         spin_unlock(&inode->i_lock);
2124
2125         err = ceph_pagelist_append(pagelist, &rec, sizeof(rec));
2126
2127 out:
2128         kfree(path);
2129         dput(dentry);
2130         return err;
2131 }
2132
2133
2134 /*
2135  * If an MDS fails and recovers, clients need to reconnect in order to
2136  * reestablish shared state.  This includes all caps issued through
2137  * this session _and_ the snap_realm hierarchy.  Because it's not
2138  * clear which snap realms the mds cares about, we send everything we
2139  * know about.. that ensures we'll then get any new info the
2140  * recovering MDS might have.
2141  *
2142  * This is a relatively heavyweight operation, but it's rare.
2143  *
2144  * called with mdsc->mutex held.
2145  */
2146 static void send_mds_reconnect(struct ceph_mds_client *mdsc, int mds)
2147 {
2148         struct ceph_mds_session *session = NULL;
2149         struct ceph_msg *reply;
2150         struct rb_node *p;
2151         int err = -ENOMEM;
2152         struct ceph_pagelist *pagelist;
2153
2154         pr_info("reconnect to recovering mds%d\n", mds);
2155
2156         pagelist = kmalloc(sizeof(*pagelist), GFP_NOFS);
2157         if (!pagelist)
2158                 goto fail_nopagelist;
2159         ceph_pagelist_init(pagelist);
2160
2161         reply = ceph_msg_new(CEPH_MSG_CLIENT_RECONNECT, 0, 0, 0, NULL);
2162         if (IS_ERR(reply)) {
2163                 err = PTR_ERR(reply);
2164                 goto fail_nomsg;
2165         }
2166
2167         /* find session */
2168         session = __ceph_lookup_mds_session(mdsc, mds);
2169         mutex_unlock(&mdsc->mutex);    /* drop lock for duration */
2170
2171         if (session) {
2172                 mutex_lock(&session->s_mutex);
2173
2174                 session->s_state = CEPH_MDS_SESSION_RECONNECTING;
2175                 session->s_seq = 0;
2176
2177                 ceph_con_open(&session->s_con,
2178                               ceph_mdsmap_get_addr(mdsc->mdsmap, mds));
2179
2180                 /* replay unsafe requests */
2181                 replay_unsafe_requests(mdsc, session);
2182         } else {
2183                 dout("no session for mds%d, will send short reconnect\n",
2184                      mds);
2185         }
2186
2187         down_read(&mdsc->snap_rwsem);
2188
2189         if (!session)
2190                 goto send;
2191         dout("session %p state %s\n", session,
2192              session_state_name(session->s_state));
2193
2194         /* traverse this session's caps */
2195         err = ceph_pagelist_encode_32(pagelist, session->s_nr_caps);
2196         if (err)
2197                 goto fail;
2198         err = iterate_session_caps(session, encode_caps_cb, pagelist);
2199         if (err < 0)
2200                 goto fail;
2201
2202         /*
2203          * snaprealms.  we provide mds with the ino, seq (version), and
2204          * parent for all of our realms.  If the mds has any newer info,
2205          * it will tell us.
2206          */
2207         for (p = rb_first(&mdsc->snap_realms); p; p = rb_next(p)) {
2208                 struct ceph_snap_realm *realm =
2209                         rb_entry(p, struct ceph_snap_realm, node);
2210                 struct ceph_mds_snaprealm_reconnect sr_rec;
2211
2212                 dout(" adding snap realm %llx seq %lld parent %llx\n",
2213                      realm->ino, realm->seq, realm->parent_ino);
2214                 sr_rec.ino = cpu_to_le64(realm->ino);
2215                 sr_rec.seq = cpu_to_le64(realm->seq);
2216                 sr_rec.parent = cpu_to_le64(realm->parent_ino);
2217                 err = ceph_pagelist_append(pagelist, &sr_rec, sizeof(sr_rec));
2218                 if (err)
2219                         goto fail;
2220         }
2221
2222 send:
2223         reply->pagelist = pagelist;
2224         reply->hdr.data_len = cpu_to_le32(pagelist->length);
2225         reply->nr_pages = calc_pages_for(0, pagelist->length);
2226         ceph_con_send(&session->s_con, reply);
2227
2228         session->s_state = CEPH_MDS_SESSION_OPEN;
2229         mutex_unlock(&session->s_mutex);
2230
2231         mutex_lock(&mdsc->mutex);
2232         __wake_requests(mdsc, &session->s_waiting);
2233         mutex_unlock(&mdsc->mutex);
2234
2235         ceph_put_mds_session(session);
2236
2237         up_read(&mdsc->snap_rwsem);
2238         mutex_lock(&mdsc->mutex);
2239         return;
2240
2241 fail:
2242         ceph_msg_put(reply);
2243         up_read(&mdsc->snap_rwsem);
2244         mutex_unlock(&session->s_mutex);
2245         ceph_put_mds_session(session);
2246 fail_nomsg:
2247         ceph_pagelist_release(pagelist);
2248         kfree(pagelist);
2249 fail_nopagelist:
2250         pr_err("error %d preparing reconnect for mds%d\n", err, mds);
2251         mutex_lock(&mdsc->mutex);
2252         return;
2253 }
2254
2255
2256 /*
2257  * compare old and new mdsmaps, kicking requests
2258  * and closing out old connections as necessary
2259  *
2260  * called under mdsc->mutex.
2261  */
2262 static void check_new_map(struct ceph_mds_client *mdsc,
2263                           struct ceph_mdsmap *newmap,
2264                           struct ceph_mdsmap *oldmap)
2265 {
2266         int i;
2267         int oldstate, newstate;
2268         struct ceph_mds_session *s;
2269
2270         dout("check_new_map new %u old %u\n",
2271              newmap->m_epoch, oldmap->m_epoch);
2272
2273         for (i = 0; i < oldmap->m_max_mds && i < mdsc->max_sessions; i++) {
2274                 if (mdsc->sessions[i] == NULL)
2275                         continue;
2276                 s = mdsc->sessions[i];
2277                 oldstate = ceph_mdsmap_get_state(oldmap, i);
2278                 newstate = ceph_mdsmap_get_state(newmap, i);
2279
2280                 dout("check_new_map mds%d state %s -> %s (session %s)\n",
2281                      i, ceph_mds_state_name(oldstate),
2282                      ceph_mds_state_name(newstate),
2283                      session_state_name(s->s_state));
2284
2285                 if (memcmp(ceph_mdsmap_get_addr(oldmap, i),
2286                            ceph_mdsmap_get_addr(newmap, i),
2287                            sizeof(struct ceph_entity_addr))) {
2288                         if (s->s_state == CEPH_MDS_SESSION_OPENING) {
2289                                 /* the session never opened, just close it
2290                                  * out now */
2291                                 __wake_requests(mdsc, &s->s_waiting);
2292                                 __unregister_session(mdsc, s);
2293                         } else {
2294                                 /* just close it */
2295                                 mutex_unlock(&mdsc->mutex);
2296                                 mutex_lock(&s->s_mutex);
2297                                 mutex_lock(&mdsc->mutex);
2298                                 ceph_con_close(&s->s_con);
2299                                 mutex_unlock(&s->s_mutex);
2300                                 s->s_state = CEPH_MDS_SESSION_RESTARTING;
2301                         }
2302
2303                         /* kick any requests waiting on the recovering mds */
2304                         kick_requests(mdsc, i, 1);
2305                 } else if (oldstate == newstate) {
2306                         continue;  /* nothing new with this mds */
2307                 }
2308
2309                 /*
2310                  * send reconnect?
2311                  */
2312                 if (s->s_state == CEPH_MDS_SESSION_RESTARTING &&
2313                     newstate >= CEPH_MDS_STATE_RECONNECT)
2314                         send_mds_reconnect(mdsc, i);
2315
2316                 /*
2317                  * kick requests on any mds that has gone active.
2318                  *
2319                  * kick requests on cur or forwarder: we may have sent
2320                  * the request to mds1, mds1 told us it forwarded it
2321                  * to mds2, but then we learn mds1 failed and can't be
2322                  * sure it successfully forwarded our request before
2323                  * it died.
2324                  */
2325                 if (oldstate < CEPH_MDS_STATE_ACTIVE &&
2326                     newstate >= CEPH_MDS_STATE_ACTIVE) {
2327                         pr_info("mds%d reconnect completed\n", s->s_mds);
2328                         kick_requests(mdsc, i, 1);
2329                         ceph_kick_flushing_caps(mdsc, s);
2330                         wake_up_session_caps(s, 1);
2331                 }
2332         }
2333 }
2334
2335
2336
2337 /*
2338  * leases
2339  */
2340
2341 /*
2342  * caller must hold session s_mutex, dentry->d_lock
2343  */
2344 void __ceph_mdsc_drop_dentry_lease(struct dentry *dentry)
2345 {
2346         struct ceph_dentry_info *di = ceph_dentry(dentry);
2347
2348         ceph_put_mds_session(di->lease_session);
2349         di->lease_session = NULL;
2350 }
2351
2352 static void handle_lease(struct ceph_mds_client *mdsc,
2353                          struct ceph_mds_session *session,
2354                          struct ceph_msg *msg)
2355 {
2356         struct super_block *sb = mdsc->client->sb;
2357         struct inode *inode;
2358         struct ceph_inode_info *ci;
2359         struct dentry *parent, *dentry;
2360         struct ceph_dentry_info *di;
2361         int mds = session->s_mds;
2362         struct ceph_mds_lease *h = msg->front.iov_base;
2363         struct ceph_vino vino;
2364         int mask;
2365         struct qstr dname;
2366         int release = 0;
2367
2368         dout("handle_lease from mds%d\n", mds);
2369
2370         /* decode */
2371         if (msg->front.iov_len < sizeof(*h) + sizeof(u32))
2372                 goto bad;
2373         vino.ino = le64_to_cpu(h->ino);
2374         vino.snap = CEPH_NOSNAP;
2375         mask = le16_to_cpu(h->mask);
2376         dname.name = (void *)h + sizeof(*h) + sizeof(u32);
2377         dname.len = msg->front.iov_len - sizeof(*h) - sizeof(u32);
2378         if (dname.len != get_unaligned_le32(h+1))
2379                 goto bad;
2380
2381         mutex_lock(&session->s_mutex);
2382         session->s_seq++;
2383
2384         /* lookup inode */
2385         inode = ceph_find_inode(sb, vino);
2386         dout("handle_lease '%s', mask %d, ino %llx %p\n",
2387              ceph_lease_op_name(h->action), mask, vino.ino, inode);
2388         if (inode == NULL) {
2389                 dout("handle_lease no inode %llx\n", vino.ino);
2390                 goto release;
2391         }
2392         ci = ceph_inode(inode);
2393
2394         /* dentry */
2395         parent = d_find_alias(inode);
2396         if (!parent) {
2397                 dout("no parent dentry on inode %p\n", inode);
2398                 WARN_ON(1);
2399                 goto release;  /* hrm... */
2400         }
2401         dname.hash = full_name_hash(dname.name, dname.len);
2402         dentry = d_lookup(parent, &dname);
2403         dput(parent);
2404         if (!dentry)
2405                 goto release;
2406
2407         spin_lock(&dentry->d_lock);
2408         di = ceph_dentry(dentry);
2409         switch (h->action) {
2410         case CEPH_MDS_LEASE_REVOKE:
2411                 if (di && di->lease_session == session) {
2412                         h->seq = cpu_to_le32(di->lease_seq);
2413                         __ceph_mdsc_drop_dentry_lease(dentry);
2414                 }
2415                 release = 1;
2416                 break;
2417
2418         case CEPH_MDS_LEASE_RENEW:
2419                 if (di && di->lease_session == session &&
2420                     di->lease_gen == session->s_cap_gen &&
2421                     di->lease_renew_from &&
2422                     di->lease_renew_after == 0) {
2423                         unsigned long duration =
2424                                 le32_to_cpu(h->duration_ms) * HZ / 1000;
2425
2426                         di->lease_seq = le32_to_cpu(h->seq);
2427                         dentry->d_time = di->lease_renew_from + duration;
2428                         di->lease_renew_after = di->lease_renew_from +
2429                                 (duration >> 1);
2430                         di->lease_renew_from = 0;
2431                 }
2432                 break;
2433         }
2434         spin_unlock(&dentry->d_lock);
2435         dput(dentry);
2436
2437         if (!release)
2438                 goto out;
2439
2440 release:
2441         /* let's just reuse the same message */
2442         h->action = CEPH_MDS_LEASE_REVOKE_ACK;
2443         ceph_msg_get(msg);
2444         ceph_con_send(&session->s_con, msg);
2445
2446 out:
2447         iput(inode);
2448         mutex_unlock(&session->s_mutex);
2449         return;
2450
2451 bad:
2452         pr_err("corrupt lease message\n");
2453         ceph_msg_dump(msg);
2454 }
2455
2456 void ceph_mdsc_lease_send_msg(struct ceph_mds_session *session,
2457                               struct inode *inode,
2458                               struct dentry *dentry, char action,
2459                               u32 seq)
2460 {
2461         struct ceph_msg *msg;
2462         struct ceph_mds_lease *lease;
2463         int len = sizeof(*lease) + sizeof(u32);
2464         int dnamelen = 0;
2465
2466         dout("lease_send_msg inode %p dentry %p %s to mds%d\n",
2467              inode, dentry, ceph_lease_op_name(action), session->s_mds);
2468         dnamelen = dentry->d_name.len;
2469         len += dnamelen;
2470
2471         msg = ceph_msg_new(CEPH_MSG_CLIENT_LEASE, len, 0, 0, NULL);
2472         if (IS_ERR(msg))
2473                 return;
2474         lease = msg->front.iov_base;
2475         lease->action = action;
2476         lease->mask = cpu_to_le16(CEPH_LOCK_DN);
2477         lease->ino = cpu_to_le64(ceph_vino(inode).ino);
2478         lease->first = lease->last = cpu_to_le64(ceph_vino(inode).snap);
2479         lease->seq = cpu_to_le32(seq);
2480         put_unaligned_le32(dnamelen, lease + 1);
2481         memcpy((void *)(lease + 1) + 4, dentry->d_name.name, dnamelen);
2482
2483         /*
2484          * if this is a preemptive lease RELEASE, no need to
2485          * flush request stream, since the actual request will
2486          * soon follow.
2487          */
2488         msg->more_to_follow = (action == CEPH_MDS_LEASE_RELEASE);
2489
2490         ceph_con_send(&session->s_con, msg);
2491 }
2492
2493 /*
2494  * Preemptively release a lease we expect to invalidate anyway.
2495  * Pass @inode always, @dentry is optional.
2496  */
2497 void ceph_mdsc_lease_release(struct ceph_mds_client *mdsc, struct inode *inode,
2498                              struct dentry *dentry, int mask)
2499 {
2500         struct ceph_dentry_info *di;
2501         struct ceph_mds_session *session;
2502         u32 seq;
2503
2504         BUG_ON(inode == NULL);
2505         BUG_ON(dentry == NULL);
2506         BUG_ON(mask != CEPH_LOCK_DN);
2507
2508         /* is dentry lease valid? */
2509         spin_lock(&dentry->d_lock);
2510         di = ceph_dentry(dentry);
2511         if (!di || !di->lease_session ||
2512             di->lease_session->s_mds < 0 ||
2513             di->lease_gen != di->lease_session->s_cap_gen ||
2514             !time_before(jiffies, dentry->d_time)) {
2515                 dout("lease_release inode %p dentry %p -- "
2516                      "no lease on %d\n",
2517                      inode, dentry, mask);
2518                 spin_unlock(&dentry->d_lock);
2519                 return;
2520         }
2521
2522         /* we do have a lease on this dentry; note mds and seq */
2523         session = ceph_get_mds_session(di->lease_session);
2524         seq = di->lease_seq;
2525         __ceph_mdsc_drop_dentry_lease(dentry);
2526         spin_unlock(&dentry->d_lock);
2527
2528         dout("lease_release inode %p dentry %p mask %d to mds%d\n",
2529              inode, dentry, mask, session->s_mds);
2530         ceph_mdsc_lease_send_msg(session, inode, dentry,
2531                                  CEPH_MDS_LEASE_RELEASE, seq);
2532         ceph_put_mds_session(session);
2533 }
2534
2535 /*
2536  * drop all leases (and dentry refs) in preparation for umount
2537  */
2538 static void drop_leases(struct ceph_mds_client *mdsc)
2539 {
2540         int i;
2541
2542         dout("drop_leases\n");
2543         mutex_lock(&mdsc->mutex);
2544         for (i = 0; i < mdsc->max_sessions; i++) {
2545                 struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
2546                 if (!s)
2547                         continue;
2548                 mutex_unlock(&mdsc->mutex);
2549                 mutex_lock(&s->s_mutex);
2550                 mutex_unlock(&s->s_mutex);
2551                 ceph_put_mds_session(s);
2552                 mutex_lock(&mdsc->mutex);
2553         }
2554         mutex_unlock(&mdsc->mutex);
2555 }
2556
2557
2558
2559 /*
2560  * delayed work -- periodically trim expired leases, renew caps with mds
2561  */
2562 static void schedule_delayed(struct ceph_mds_client *mdsc)
2563 {
2564         int delay = 5;
2565         unsigned hz = round_jiffies_relative(HZ * delay);
2566         schedule_delayed_work(&mdsc->delayed_work, hz);
2567 }
2568
2569 static void delayed_work(struct work_struct *work)
2570 {
2571         int i;
2572         struct ceph_mds_client *mdsc =
2573                 container_of(work, struct ceph_mds_client, delayed_work.work);
2574         int renew_interval;
2575         int renew_caps;
2576
2577         dout("mdsc delayed_work\n");
2578         ceph_check_delayed_caps(mdsc);
2579
2580         mutex_lock(&mdsc->mutex);
2581         renew_interval = mdsc->mdsmap->m_session_timeout >> 2;
2582         renew_caps = time_after_eq(jiffies, HZ*renew_interval +
2583                                    mdsc->last_renew_caps);
2584         if (renew_caps)
2585                 mdsc->last_renew_caps = jiffies;
2586
2587         for (i = 0; i < mdsc->max_sessions; i++) {
2588                 struct ceph_mds_session *s = __ceph_lookup_mds_session(mdsc, i);
2589                 if (s == NULL)
2590                         continue;
2591                 if (s->s_state == CEPH_MDS_SESSION_CLOSING) {
2592                         dout("resending session close request for mds%d\n",
2593                              s->s_mds);
2594                         request_close_session(mdsc, s);
2595                         ceph_put_mds_session(s);
2596                         continue;
2597                 }
2598                 if (s->s_ttl && time_after(jiffies, s->s_ttl)) {
2599                         if (s->s_state == CEPH_MDS_SESSION_OPEN) {
2600                                 s->s_state = CEPH_MDS_SESSION_HUNG;
2601                                 pr_info("mds%d hung\n", s->s_mds);
2602                         }
2603                 }
2604                 if (s->s_state < CEPH_MDS_SESSION_OPEN) {
2605                         /* this mds is failed or recovering, just wait */
2606                         ceph_put_mds_session(s);
2607                         continue;
2608                 }
2609                 mutex_unlock(&mdsc->mutex);
2610
2611                 mutex_lock(&s->s_mutex);
2612                 if (renew_caps)
2613                         send_renew_caps(mdsc, s);
2614                 else
2615                         ceph_con_keepalive(&s->s_con);
2616                 add_cap_releases(mdsc, s, -1);
2617                 send_cap_releases(mdsc, s);
2618                 mutex_unlock(&s->s_mutex);
2619                 ceph_put_mds_session(s);
2620
2621                 mutex_lock(&mdsc->mutex);
2622         }
2623         mutex_unlock(&mdsc->mutex);
2624
2625         schedule_delayed(mdsc);
2626 }
2627
2628
2629 int ceph_mdsc_init(struct ceph_mds_client *mdsc, struct ceph_client *client)
2630 {
2631         mdsc->client = client;
2632         mutex_init(&mdsc->mutex);
2633         mdsc->mdsmap = kzalloc(sizeof(*mdsc->mdsmap), GFP_NOFS);
2634         init_completion(&mdsc->safe_umount_waiters);
2635         init_completion(&mdsc->session_close_waiters);
2636         INIT_LIST_HEAD(&mdsc->waiting_for_map);
2637         mdsc->sessions = NULL;
2638         mdsc->max_sessions = 0;
2639         mdsc->stopping = 0;
2640         init_rwsem(&mdsc->snap_rwsem);
2641         mdsc->snap_realms = RB_ROOT;
2642         INIT_LIST_HEAD(&mdsc->snap_empty);
2643         spin_lock_init(&mdsc->snap_empty_lock);
2644         mdsc->last_tid = 0;
2645         mdsc->request_tree = RB_ROOT;
2646         INIT_DELAYED_WORK(&mdsc->delayed_work, delayed_work);
2647         mdsc->last_renew_caps = jiffies;
2648         INIT_LIST_HEAD(&mdsc->cap_delay_list);
2649         spin_lock_init(&mdsc->cap_delay_lock);
2650         INIT_LIST_HEAD(&mdsc->snap_flush_list);
2651         spin_lock_init(&mdsc->snap_flush_lock);
2652         mdsc->cap_flush_seq = 0;
2653         INIT_LIST_HEAD(&mdsc->cap_dirty);
2654         mdsc->num_cap_flushing = 0;
2655         spin_lock_init(&mdsc->cap_dirty_lock);
2656         init_waitqueue_head(&mdsc->cap_flushing_wq);
2657         spin_lock_init(&mdsc->dentry_lru_lock);
2658         INIT_LIST_HEAD(&mdsc->dentry_lru);
2659         return 0;
2660 }
2661
2662 /*
2663  * Wait for safe replies on open mds requests.  If we time out, drop
2664  * all requests from the tree to avoid dangling dentry refs.
2665  */
2666 static void wait_requests(struct ceph_mds_client *mdsc)
2667 {
2668         struct ceph_mds_request *req;
2669         struct ceph_client *client = mdsc->client;
2670
2671         mutex_lock(&mdsc->mutex);
2672         if (__get_oldest_req(mdsc)) {
2673                 mutex_unlock(&mdsc->mutex);
2674
2675                 dout("wait_requests waiting for requests\n");
2676                 wait_for_completion_timeout(&mdsc->safe_umount_waiters,
2677                                     client->mount_args->mount_timeout * HZ);
2678
2679                 /* tear down remaining requests */
2680                 mutex_lock(&mdsc->mutex);
2681                 while ((req = __get_oldest_req(mdsc))) {
2682                         dout("wait_requests timed out on tid %llu\n",
2683                              req->r_tid);
2684                         __unregister_request(mdsc, req);
2685                 }
2686         }
2687         mutex_unlock(&mdsc->mutex);
2688         dout("wait_requests done\n");
2689 }
2690
2691 /*
2692  * called before mount is ro, and before dentries are torn down.
2693  * (hmm, does this still race with new lookups?)
2694  */
2695 void ceph_mdsc_pre_umount(struct ceph_mds_client *mdsc)
2696 {
2697         dout("pre_umount\n");
2698         mdsc->stopping = 1;
2699
2700         drop_leases(mdsc);
2701         ceph_flush_dirty_caps(mdsc);
2702         wait_requests(mdsc);
2703 }
2704
2705 /*
2706  * wait for all write mds requests to flush.
2707  */
2708 static void wait_unsafe_requests(struct ceph_mds_client *mdsc, u64 want_tid)
2709 {
2710         struct ceph_mds_request *req = NULL, *nextreq;
2711         struct rb_node *n;
2712
2713         mutex_lock(&mdsc->mutex);
2714         dout("wait_unsafe_requests want %lld\n", want_tid);
2715 restart:
2716         req = __get_oldest_req(mdsc);
2717         while (req && req->r_tid <= want_tid) {
2718                 /* find next request */
2719                 n = rb_next(&req->r_node);
2720                 if (n)
2721                         nextreq = rb_entry(n, struct ceph_mds_request, r_node);
2722                 else
2723                         nextreq = NULL;
2724                 if ((req->r_op & CEPH_MDS_OP_WRITE)) {
2725                         /* write op */
2726                         ceph_mdsc_get_request(req);
2727                         if (nextreq)
2728                                 ceph_mdsc_get_request(nextreq);
2729                         mutex_unlock(&mdsc->mutex);
2730                         dout("wait_unsafe_requests  wait on %llu (want %llu)\n",
2731                              req->r_tid, want_tid);
2732                         wait_for_completion(&req->r_safe_completion);
2733                         mutex_lock(&mdsc->mutex);
2734                         ceph_mdsc_put_request(req);
2735                         if (!nextreq)
2736                                 break;  /* next dne before, so we're done! */
2737                         if (RB_EMPTY_NODE(&nextreq->r_node)) {
2738                                 /* next request was removed from tree */
2739                                 ceph_mdsc_put_request(nextreq);
2740                                 goto restart;
2741                         }
2742                         ceph_mdsc_put_request(nextreq);  /* won't go away */
2743                 }
2744                 req = nextreq;
2745         }
2746         mutex_unlock(&mdsc->mutex);
2747         dout("wait_unsafe_requests done\n");
2748 }
2749
2750 void ceph_mdsc_sync(struct ceph_mds_client *mdsc)
2751 {
2752         u64 want_tid, want_flush;
2753
2754         dout("sync\n");
2755         mutex_lock(&mdsc->mutex);
2756         want_tid = mdsc->last_tid;
2757         want_flush = mdsc->cap_flush_seq;
2758         mutex_unlock(&mdsc->mutex);
2759         dout("sync want tid %lld flush_seq %lld\n", want_tid, want_flush);
2760
2761         ceph_flush_dirty_caps(mdsc);
2762
2763         wait_unsafe_requests(mdsc, want_tid);
2764         wait_event(mdsc->cap_flushing_wq, check_cap_flush(mdsc, want_flush));
2765 }
2766
2767
2768 /*
2769  * called after sb is ro.
2770  */
2771 void ceph_mdsc_close_sessions(struct ceph_mds_client *mdsc)
2772 {
2773         struct ceph_mds_session *session;
2774         int i;
2775         int n;
2776         struct ceph_client *client = mdsc->client;
2777         unsigned long started, timeout = client->mount_args->mount_timeout * HZ;
2778
2779         dout("close_sessions\n");
2780
2781         mutex_lock(&mdsc->mutex);
2782
2783         /* close sessions */
2784         started = jiffies;
2785         while (time_before(jiffies, started + timeout)) {
2786                 dout("closing sessions\n");
2787                 n = 0;
2788                 for (i = 0; i < mdsc->max_sessions; i++) {
2789                         session = __ceph_lookup_mds_session(mdsc, i);
2790                         if (!session)
2791                                 continue;
2792                         mutex_unlock(&mdsc->mutex);
2793                         mutex_lock(&session->s_mutex);
2794                         __close_session(mdsc, session);
2795                         mutex_unlock(&session->s_mutex);
2796                         ceph_put_mds_session(session);
2797                         mutex_lock(&mdsc->mutex);
2798                         n++;
2799                 }
2800                 if (n == 0)
2801                         break;
2802
2803                 if (client->mount_state == CEPH_MOUNT_SHUTDOWN)
2804                         break;
2805
2806                 dout("waiting for sessions to close\n");
2807                 mutex_unlock(&mdsc->mutex);
2808                 wait_for_completion_timeout(&mdsc->session_close_waiters,
2809                                             timeout);
2810                 mutex_lock(&mdsc->mutex);
2811         }
2812
2813         /* tear down remaining sessions */
2814         for (i = 0; i < mdsc->max_sessions; i++) {
2815                 if (mdsc->sessions[i]) {
2816                         session = get_session(mdsc->sessions[i]);
2817                         __unregister_session(mdsc, session);
2818                         mutex_unlock(&mdsc->mutex);
2819                         mutex_lock(&session->s_mutex);
2820                         remove_session_caps(session);
2821                         mutex_unlock(&session->s_mutex);
2822                         ceph_put_mds_session(session);
2823                         mutex_lock(&mdsc->mutex);
2824                 }
2825         }
2826
2827         WARN_ON(!list_empty(&mdsc->cap_delay_list));
2828
2829         mutex_unlock(&mdsc->mutex);
2830
2831         ceph_cleanup_empty_realms(mdsc);
2832
2833         cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
2834
2835         dout("stopped\n");
2836 }
2837
2838 void ceph_mdsc_stop(struct ceph_mds_client *mdsc)
2839 {
2840         dout("stop\n");
2841         cancel_delayed_work_sync(&mdsc->delayed_work); /* cancel timer */
2842         if (mdsc->mdsmap)
2843                 ceph_mdsmap_destroy(mdsc->mdsmap);
2844         kfree(mdsc->sessions);
2845 }
2846
2847
2848 /*
2849  * handle mds map update.
2850  */
2851 void ceph_mdsc_handle_map(struct ceph_mds_client *mdsc, struct ceph_msg *msg)
2852 {
2853         u32 epoch;
2854         u32 maplen;
2855         void *p = msg->front.iov_base;
2856         void *end = p + msg->front.iov_len;
2857         struct ceph_mdsmap *newmap, *oldmap;
2858         struct ceph_fsid fsid;
2859         int err = -EINVAL;
2860
2861         ceph_decode_need(&p, end, sizeof(fsid)+2*sizeof(u32), bad);
2862         ceph_decode_copy(&p, &fsid, sizeof(fsid));
2863         if (ceph_check_fsid(mdsc->client, &fsid) < 0)
2864                 return;
2865         epoch = ceph_decode_32(&p);
2866         maplen = ceph_decode_32(&p);
2867         dout("handle_map epoch %u len %d\n", epoch, (int)maplen);
2868
2869         /* do we need it? */
2870         ceph_monc_got_mdsmap(&mdsc->client->monc, epoch);
2871         mutex_lock(&mdsc->mutex);
2872         if (mdsc->mdsmap && epoch <= mdsc->mdsmap->m_epoch) {
2873                 dout("handle_map epoch %u <= our %u\n",
2874                      epoch, mdsc->mdsmap->m_epoch);
2875                 mutex_unlock(&mdsc->mutex);
2876                 return;
2877         }
2878
2879         newmap = ceph_mdsmap_decode(&p, end);
2880         if (IS_ERR(newmap)) {
2881                 err = PTR_ERR(newmap);
2882                 goto bad_unlock;
2883         }
2884
2885         /* swap into place */
2886         if (mdsc->mdsmap) {
2887                 oldmap = mdsc->mdsmap;
2888                 mdsc->mdsmap = newmap;
2889                 check_new_map(mdsc, newmap, oldmap);
2890                 ceph_mdsmap_destroy(oldmap);
2891         } else {
2892                 mdsc->mdsmap = newmap;  /* first mds map */
2893         }
2894         mdsc->client->sb->s_maxbytes = mdsc->mdsmap->m_max_file_size;
2895
2896         __wake_requests(mdsc, &mdsc->waiting_for_map);
2897
2898         mutex_unlock(&mdsc->mutex);
2899         schedule_delayed(mdsc);
2900         return;
2901
2902 bad_unlock:
2903         mutex_unlock(&mdsc->mutex);
2904 bad:
2905         pr_err("error decoding mdsmap %d\n", err);
2906         return;
2907 }
2908
2909 static struct ceph_connection *con_get(struct ceph_connection *con)
2910 {
2911         struct ceph_mds_session *s = con->private;
2912
2913         if (get_session(s)) {
2914                 dout("mdsc con_get %p ok (%d)\n", s, atomic_read(&s->s_ref));
2915                 return con;
2916         }
2917         dout("mdsc con_get %p FAIL\n", s);
2918         return NULL;
2919 }
2920
2921 static void con_put(struct ceph_connection *con)
2922 {
2923         struct ceph_mds_session *s = con->private;
2924
2925         ceph_put_mds_session(s);
2926         dout("mdsc con_put %p (%d)\n", s, atomic_read(&s->s_ref));
2927 }
2928
2929 /*
2930  * if the client is unresponsive for long enough, the mds will kill
2931  * the session entirely.
2932  */
2933 static void peer_reset(struct ceph_connection *con)
2934 {
2935         struct ceph_mds_session *s = con->private;
2936
2937         pr_err("mds%d gave us the boot.  IMPLEMENT RECONNECT.\n",
2938                s->s_mds);
2939 }
2940
2941 static void dispatch(struct ceph_connection *con, struct ceph_msg *msg)
2942 {
2943         struct ceph_mds_session *s = con->private;
2944         struct ceph_mds_client *mdsc = s->s_mdsc;
2945         int type = le16_to_cpu(msg->hdr.type);
2946
2947         mutex_lock(&mdsc->mutex);
2948         if (__verify_registered_session(mdsc, s) < 0) {
2949                 mutex_unlock(&mdsc->mutex);
2950                 goto out;
2951         }
2952         mutex_unlock(&mdsc->mutex);
2953
2954         switch (type) {
2955         case CEPH_MSG_MDS_MAP:
2956                 ceph_mdsc_handle_map(mdsc, msg);
2957                 break;
2958         case CEPH_MSG_CLIENT_SESSION:
2959                 handle_session(s, msg);
2960                 break;
2961         case CEPH_MSG_CLIENT_REPLY:
2962                 handle_reply(s, msg);
2963                 break;
2964         case CEPH_MSG_CLIENT_REQUEST_FORWARD:
2965                 handle_forward(mdsc, s, msg);
2966                 break;
2967         case CEPH_MSG_CLIENT_CAPS:
2968                 ceph_handle_caps(s, msg);
2969                 break;
2970         case CEPH_MSG_CLIENT_SNAP:
2971                 ceph_handle_snap(mdsc, s, msg);
2972                 break;
2973         case CEPH_MSG_CLIENT_LEASE:
2974                 handle_lease(mdsc, s, msg);
2975                 break;
2976
2977         default:
2978                 pr_err("received unknown message type %d %s\n", type,
2979                        ceph_msg_type_name(type));
2980         }
2981 out:
2982         ceph_msg_put(msg);
2983 }
2984
2985 /*
2986  * authentication
2987  */
2988 static int get_authorizer(struct ceph_connection *con,
2989                           void **buf, int *len, int *proto,
2990                           void **reply_buf, int *reply_len, int force_new)
2991 {
2992         struct ceph_mds_session *s = con->private;
2993         struct ceph_mds_client *mdsc = s->s_mdsc;
2994         struct ceph_auth_client *ac = mdsc->client->monc.auth;
2995         int ret = 0;
2996
2997         if (force_new && s->s_authorizer) {
2998                 ac->ops->destroy_authorizer(ac, s->s_authorizer);
2999                 s->s_authorizer = NULL;
3000         }
3001         if (s->s_authorizer == NULL) {
3002                 if (ac->ops->create_authorizer) {
3003                         ret = ac->ops->create_authorizer(
3004                                 ac, CEPH_ENTITY_TYPE_MDS,
3005                                 &s->s_authorizer,
3006                                 &s->s_authorizer_buf,
3007                                 &s->s_authorizer_buf_len,
3008                                 &s->s_authorizer_reply_buf,
3009                                 &s->s_authorizer_reply_buf_len);
3010                         if (ret)
3011                                 return ret;
3012                 }
3013         }
3014
3015         *proto = ac->protocol;
3016         *buf = s->s_authorizer_buf;
3017         *len = s->s_authorizer_buf_len;
3018         *reply_buf = s->s_authorizer_reply_buf;
3019         *reply_len = s->s_authorizer_reply_buf_len;
3020         return 0;
3021 }
3022
3023
3024 static int verify_authorizer_reply(struct ceph_connection *con, int len)
3025 {
3026         struct ceph_mds_session *s = con->private;
3027         struct ceph_mds_client *mdsc = s->s_mdsc;
3028         struct ceph_auth_client *ac = mdsc->client->monc.auth;
3029
3030         return ac->ops->verify_authorizer_reply(ac, s->s_authorizer, len);
3031 }
3032
3033 static int invalidate_authorizer(struct ceph_connection *con)
3034 {
3035         struct ceph_mds_session *s = con->private;
3036         struct ceph_mds_client *mdsc = s->s_mdsc;
3037         struct ceph_auth_client *ac = mdsc->client->monc.auth;
3038
3039         if (ac->ops->invalidate_authorizer)
3040                 ac->ops->invalidate_authorizer(ac, CEPH_ENTITY_TYPE_MDS);
3041
3042         return ceph_monc_validate_auth(&mdsc->client->monc);
3043 }
3044
3045 const static struct ceph_connection_operations mds_con_ops = {
3046         .get = con_get,
3047         .put = con_put,
3048         .dispatch = dispatch,
3049         .get_authorizer = get_authorizer,
3050         .verify_authorizer_reply = verify_authorizer_reply,
3051         .invalidate_authorizer = invalidate_authorizer,
3052         .peer_reset = peer_reset,
3053 };
3054
3055
3056
3057
3058 /* eof */