fs/ceph/mds_client.c

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  36  * are no longer valid.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