Pileus Git - ~andy/linux/blob - fs/ceph/mds_client.c

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  42  * are no longer valid.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